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  • 1.
    A. Strumpfer, Johan
    et al.
    University of Illinois at Urbana Champaign, Urbana, IL, USA; Beckman Institute, Urbana, IL, USA.
    von Castelmur, Eleonore
    Institute of Integrative Biology, University of Liverpool, Liverpool, IL, USA.
    Franke, Barbara
    Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom.
    Barbieri, Sonia
    Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom.
    Bogomolovas, Julijus
    Universitätsmedizin Mannheim, Mannheim, Germany.
    Qadota, Hiroshi
    Department of Pathology, Emory University, Atlanta, GA, USA.
    Konarv, Petr
    European Molecular Biology Laboratory, Hamburg, Germany.
    Svergun, Dmitri
    European Molecular Biology Laboratory, Hamburg, Germany.
    Labeit, Siegfried
    Department for Integrative Pathophysiology, Universitätsmedizin Mannheim, Mannheim, Germany.
    Schulten, Klaus
    University of Illinois at Urbana Champaign, Urbana, IL, USA Beckman Institute, Urbana, IL, USA.
    Benian, Guy
    Department of Pathology, Emory University, Atlanta, GA, USA.
    Mayans, Olga
    Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom.
    Stretching of Twitchin Kinase2012In: Biophysical Journal, ISSN 0006-3495, E-ISSN 1542-0086, Vol. 102, no 3 Supplement 1, p. 361a-362aArticle in journal (Refereed)
    Abstract [en]

    The giant proteins from the titin family, that form cytoskeletal filaments, have emerged as key mechanotransducers in the sarcomere. These proteins contain a conserved kinase region, which is auto-inhibited by a C-terminal tail domain. The inhibitory tail domain occludes the active sites of the kinases, thus preventing ATP from binding. It was proposed that through application of a force, such as that arising during muscle contraction, the inhibitory tail becomes detached, lifting inhibition. The force-sensing ability of titin kinase was demonstrated in AFM experiments and simulations [Puchner, et al., 2008, PNAS:105, 13385], which showed indeed that mechanical forces can remove the autoinhibitory tail of titin kinase. We report here steered molecular dynamics simulations (SMD) of the very recently resolved crystal structure of twitchin kinase, containing the kinase region and flanking fibronectin and immuniglobulin domains, that show a variant mechanism. Despite the significant structural and sequence similarity to titin kinase, the autoinhibitory tail of twitchin kinase remains in place upon stretching, while the N-terminal lobe of the kinase unfolds. The SMD simulations also show that the detachment and stretching of the linker between fibronectin and kinase regions, and the partial extension of the autoinhibitory tail, are the primary force-response. We postulate that this stretched state, where all structural elements are still intact, may represent the physiologically active state.

  • 2.
    Abbasy, Leila
    et al.
    Tabriz University of Medical Sciences, Iran.
    Mohammadzadeh, Arezoo
    Tabriz University of Medical Sciences, Iran.
    Hasanzadeh, Mohammad
    Tabriz University of Medical Sciences, Iran.
    Razmi, Nasrin
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, Faculty of Science & Engineering.
    Development of a reliable bioanalytical method based on prostate specific antigen trapping on the cavity of molecular imprinted polymer towards sensing of PSA using binding affinity of PSA-MIP receptor: A novel biosensor2020In: Journal of Pharmaceutical and Biomedical Analysis, ISSN 0731-7085, E-ISSN 1873-264X, Vol. 188, article id 113447Article in journal (Refereed)
    Abstract [en]

    In this study, electrically-conducting poly [Toluidine Blue (PTB)] was applied as artificial receptor. It was organized by molecular imprinting approaches and via electrochemical technique for the sensitive monitoring of prostate-specific antigen (PSA). The protein-imprinted PTB was electropolymerized in a pre-formed glutaraldehyde-cysteamine (GA-Cys A) matrix on the surface of gold electrode, which significantly boosted the stability against degradation of the Molecular Imprinted Polymer (MIP) on the surface of pre-modified gold electrode. Moreover, the MIP bio-receptor ability towards protein recognition was explored by some electrochemical techniques. The binding affinity of MIP system was considerably upper than that of non-imprinted polymer (NIP) system, indicating the success of the method in generating imprinted materials that was specifically use to PSA protein. The incubation of the MIP modified electrode in various concentration of PSA (from 1-60 μg/L) resulted in the increase of the Fe (CN)63-/4- redox peak current. The bio-device also showed linear response from 1-60 μg/L and LLOQ of 1 μg/L by using DPV technique, leading to PSA monitoring in clinical samples. The proposed MIP-based biosensor was satisfactorily applied to the determination of PSA in human plasma samples. Therefore, the developed bio-device provides a new approach for sensitive, simple, rapid, and cost-effective monitoring of 1 μg/L of PSA. Notably, this approach could appear as an appropriate candidate for point-of-care (POC) use in clinical and biomedical analyses.

  • 3.
    Abdala, Esraa
    et al.
    Department of Chemical Engineering, University of Khartoum, Khartoum, Sudan.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, Faculty of Science & Engineering.
    Mustafa, Mustafa A.
    Materials and Nanotechnology Research Centre, University of Khartoum, Khartoum, Sudan.
    Efficient Biodiesel Production from Algae Oil Using Ca-Doped ZnO Nanocatalyst2020In: Industrial & Engineering Chemistry Research, ISSN 0888-5885, E-ISSN 1520-5045, Vol. 59, no 43, p. 19235-19243Article in journal (Refereed)
    Abstract [en]

    Biodiesel is a sustainable alternative to petroleum diesel produced by transesterification of vegetable oils in the presence of a catalyst. The present study investigates heterogeneous transesterification of algal oil to biodiesel using novel calcium-doped zinc oxide nanocatalysts synthesized using a UV shaker. The developed catalyst was under different light sources, UV and non-UV; different calcium concentrations (0.01, 0.03, 0.05 M); and different calcination temperatures (600, 700, 800 degrees C). The catalyst has been characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, and energy-dispersive spectroscopy (EDS). The effects of the different parameters used in catalyst preparation were studied for transesterification of algal oil. The catalyst of 0.05 M calcium loading and 700 degrees C calcination temperature synthesized in UV light is considered as the most suitable nanocatalyst, which achieved 99.18% yield of biodiesel. The catalyst was used three times effectively with 76% yield. The chemical properties of biodiesel have been investigated using gas chromatography (GC).

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  • 4. Order onlineBuy this publication >>
    Abrahamsson, Tobias
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Synthetic Functionalities for Ion and Electron Conductive Polymers: Applications in Organic Electronics and Biological Interfaces2021Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In the search for understanding and communicating with all biological systems, in humans, animals, plants, and even microorganisms, we find a common language of all communicating via electrons, ions and molecules. Since the discovery of organic electronics, the ability to bridge the gap and communicate be-tween modern technology and biology has emerged. Organic chemistry pro-vides us with tools for understanding and a material platform of polymer electronics for communication. Such insights give us not only the ability to observe fundamental phenomenon but to actively design and construct materials with chemical functionalities towards better interfaces and applications. Organic electronic materials and devices have found their way to be implemented in the field of medicine for diagnostic and therapeutic purposes, but also in water purification and to help tackle the monumental task in creating the next generation of sustainable energy production and storage. Ultimately it’s safe to say that organic electronics are not going to replace our traditional technology based on inorganic materials but rather the two fields can find a way to complement each other for various purposes and applications. Compared to conventional silicon based technology, production of carbon-based organic electronic polymer materials are extremely cheap and devices can even be made flexible and soft with great compatibility towards biology.  

    The main focus of this thesis has been developing and synthesizing new types of organic electronic and ionic conductive polymeric materials. Rational chemical design and modifications of the materials have been utilized to introduce specific functionalities to the materials. The functionalities serving the purpose to facilitate ion and electron conductive charge transport for organic electronics and with biological interface implementation of the polymer materials. 

    Multi-functional ionic conductive hyperbranched polyglycerol polyelectrolytes (dendrolytes) were developed comprising both ionically charged groups and cross-linkable groups. The hyperbranched polyglycerol core structure of the material possesses a hydrophilic solvating platform for both ions and maintenance of solvent molecules, while being a biocompatible structure. Coupled with the peripheral charged ionic functionalities of the polymer, the dendrolyte materials are highly ionic conductive and selective towards cationic and anionic charged atoms and large molecules when implemented as ion-exchange membranes. Homogenous ion-exchange membrane casting has been achieved by the implementation of cross-linkable functionalities in the dendrolytes, utilizing robust click-chemistry for efficient micro and macro fabrication processing of the ion-ex-change membranes for organic electronic devices. The ion-exchange membrane material was implemented in electrophoretic drug delivery devices (organic electronic ion pumps), which are used for delivery of ions and neurotransmitters with spatiotemporal resolution and are able to communicate and be used for therapeutic drug delivery purposes in biological interfaces. The dendrolyte materials were also able to form free-standing membranes, making it possible for implementation in fuel cell and desalination purposes. 

    Trimeric conjugated thiophene pre-polymer structures were also developed in the thesis and synthesized for the purpose of implementation of the material in vivo to form electrically conductive polymer structures, and in such manner to be able to create electrodes and ultimately to connect with the central nervous system. The conjugated pre-polymers being both water soluble and enzymatically polymerizable serve as a platform to realize such a concept. Also, modifying the trimeric structure with cross-linkable functionality created the capability to form better interfaces and stability towards biological environments.   

    List of papers
    1. Formation of Monolithic Ion-Selective Transport Media Based on "Click" Cross-Linked Hyperbranched Polyglycerol
    Open this publication in new window or tab >>Formation of Monolithic Ion-Selective Transport Media Based on "Click" Cross-Linked Hyperbranched Polyglycerol
    Show others...
    2019 (English)In: Frontiers in Chemistry, E-ISSN 2296-2646, Vol. 7, article id 484Article in journal (Refereed) Published
    Abstract [en]

    In the emerging field of organic bioelectronics, conducting polymers and ion-selective membranes are combined to form resistors, diodes, transistors, and circuits that transport and process both electronic and ionic signals. Such bioelectronics concepts have been explored in delivery devices that translate electronic addressing signals into the transport and dispensing of small charged biomolecules at high specificity and spatiotemporal resolution. Manufacturing such "iontronic" devices generally involves classical thin film processing of polyelectrolyte layers and insulators followed by application of electrolytes. This approach makes miniaturization and integration difficult, simply because the ion selective polyelectrolytes swell after completing the manufacturing. To advance such bioelectronics/iontronics and to enable applications where relatively larger molecules can be delivered, it is important to develop a versatile material system in which the charge/size selectivity can be easily tailormade at the same time enabling easy manufacturing of complex and miniaturized structures. Here, we report a one-pot synthesis approach with minimal amount of organic solvent to achieve cationic hyperbranched polyglycerol films for iontronics applications. The hyperbranched structure allows for tunable pre multi-functionalization, which combines available unsaturated groups used in crosslinking along with ionic groups for electrolytic properties, to achieve a one-step process when applied in devices for monolithic membrane gel formation with selective electrophoretic transport of molecules.

    Place, publisher, year, edition, pages
    FRONTIERS MEDIA SA, 2019
    Keywords
    hyperbranched polyglycerol; polyelectrolyte; multi-functionalization; thiol-ene; cross-linking; ion-selective; electrophoretic transport
    National Category
    Materials Chemistry
    Identifiers
    urn:nbn:se:liu:diva-159146 (URN)10.3389/fchem.2019.00484 (DOI)000474717900001 ()
    Note

    Funding Agencies|Swedish Foundation for Strategic Research; Swedish Government Strategic Research Area in Materials Science on Advanced Functional Materials at Linkoping University; Onnesjo Foundation; Knut and AliceWallenberg Foundation

    Available from: 2019-07-30 Created: 2019-07-30 Last updated: 2024-01-10
    2. Capillary-Fiber Based Electrophoretic Delivery Device
    Open this publication in new window or tab >>Capillary-Fiber Based Electrophoretic Delivery Device
    Show others...
    2019 (English)In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 11, no 15, p. 14200-14207Article in journal (Refereed) Published
    Abstract [en]

    Organic electronic ion pumps (OEIPs) are versatile tools for electrophoretic delivery of substances with high spatiotemporal resolution. To date, OEIPs and similar iontronic components have been fabricated using thin-film techniques and often rely on laborious, multistep photolithographic processes. OEIPs have been demonstrated in a variety of in vitro and in vivo settings for controlling biological systems, but the thin-film form factor and limited repertoire of polyelectrolyte materials and device fabrication techniques unnecessarily constrain the possibilities for miniaturization and extremely localized substance delivery, e.g., the greater range of pharmaceutical compounds, on the scale of a single cell. Here, we demonstrate an entirely new OEIP form factor based on capillary fibers that include hyperbranched polyglycerols (dPGs) as the selective electrophoretic membrane. The dPGs enable electrophoretic channels with a high concentration of fixed charges and well-controlled cross-linking and can be realized using a simple one-pot fluidic manufacturing protocol. Selective electrophoretic transport of cations and anions of various sizes is demonstrated, including large substances that are difficult to transport with other OEIP technologies. We present a method for tailoring and characterizing the electrophoretic channels fixed charge concentration in the operational state. Subsequently, we compare the experimental performance of these capillary OEIPs to a computational model and explain unexpected features in the ionic current for the transport and delivery of larger, lower-mobility ionic compounds. From this model, we are able to elucidate several operational and design principles relevant to miniaturized electrophoretic drug delivery technologies in general. Overall, the compactness of the capillary OEIP enables electrophoretic delivery devices with probelike geometries, suitable for a variety of ionic compounds, paving the way for less-invasive implantation into biological systems and for healthcare applications.

    Place, publisher, year, edition, pages
    AMER CHEMICAL SOC, 2019
    Keywords
    electrophoresis; polyelectrolyte; iontronics; hyperbranched polymer; bioelectronics; substance delivery
    National Category
    Other Physics Topics
    Identifiers
    urn:nbn:se:liu:diva-157207 (URN)10.1021/acsami.8b022680 (DOI)000465189000042 ()
    Note

    Funding Agencies|Swedish Foundation for Strategic Research; Swedish Government Strategic Research Area in Materials Science on Advanced Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009-00971]; Onnesjo Foundation; Knut and Alice Wallenberg Foundation

    Available from: 2019-06-14 Created: 2019-06-14 Last updated: 2024-01-10
    3. Investigating the role of polymer size on ionic conductivity in free-standing hyperbranched polyelectrolyte membranes
    Open this publication in new window or tab >>Investigating the role of polymer size on ionic conductivity in free-standing hyperbranched polyelectrolyte membranes
    Show others...
    2021 (English)In: Polymer, ISSN 0032-3861, E-ISSN 1873-2291, Vol. 223, article id 123664Article in journal (Refereed) Published
    Abstract [en]

    Polymer-based ion exchange membranes (IEMs) are utilized for many applications such as in water desalination, energy storage, fuel cells and in electrophoretic drug delivery devices, exemplified by the organic electronic ion pump (OEIP). The bulk of current research is primarily focused on finding highly conductive and stable IEM materials. Even though great progress has been made, a lack of fundamental understanding of how specific polymer properties affect ionic transport capabilities still remains. This leads to uncertainty in how to proceed with synthetic approaches for designing better IEM materials. In this study, an investigation of the structure-property relationship between polymer size and ionic conductivity was performed by comparing a series of membranes, based on ionically charged hyperbranched polyglycerol of different polymer sizes. Observing an increase in ionic conductivity associated with increasing polymer size and greater electrolyte exclusion, indi-cating an ionic transportation phenomenon not exclusively based on membrane electrolyte uptake. These findings further our understanding of ion transport phenomena in semi-permeable membranes and indicate a strong starting point for future design and synthesis of IEM polymers to achieve broader capabilities for a variety of ion transport-based applications.

    Place, publisher, year, edition, pages
    Elsevier, 2021
    Keywords
    Ion-exchange membrane; Polymer size dependant ionic conductivity; Hyperbranched polyelectrolyte; Multi-functionalization; Click cross-linking
    National Category
    Polymer Chemistry
    Identifiers
    urn:nbn:se:liu:diva-175830 (URN)10.1016/j.polymer.2021.123664 (DOI)000643930300006 ()
    Note

    Funding Agencies|Swiss Society for Biomaterials and Regenerative Medicine, SSB + RM; Swedish Foundation for Strategic ResearchSwedish Foundation for Strategic Research; Swedish Research CouncilSwedish Research CouncilEuropean Commission; European UnionEuropean Commission [834677]

    Available from: 2021-05-26 Created: 2021-05-26 Last updated: 2023-12-28
    4. Seamless integration of bioelectronic interface in an animal model via in vivo polymerization of conjugated oligomers
    Open this publication in new window or tab >>Seamless integration of bioelectronic interface in an animal model via in vivo polymerization of conjugated oligomers
    Show others...
    2022 (English)In: Bioactive Materials, ISSN 2452-199X, Vol. 10, p. 107-116Article in journal (Refereed) Published
    Abstract [en]

    Leveraging the biocatalytic machinery of living organisms for fabricating functional bioelectronic interfaces, in vivo, defines a new class of micro-biohybrids enabling the seamless integration of technology with living biological systems. Previously, we have demonstrated the in vivo polymerization of conjugated oligomers forming conductors within the structures of plants. Here, we expand this concept by reporting that Hydra, an invertebrate animal, polymerizes the conjugated oligomer ETE-S both within cells that expresses peroxidase activity and within the adhesive material that is secreted to promote underwater surface adhesion. The resulting conjugated polymer forms electronically conducting and electrochemically active μm-sized domains, which are inter-connected resulting in percolative conduction pathways extending beyond 100 μm, that are fully integrated within the Hydra tissue and the secreted mucus. Furthermore, the introduction and in vivo polymerization of ETE-S can be used as a biochemical marker to follow the dynamics of Hydra budding (reproduction) and regeneration. This work paves the way for well-defined self-organized electronics in animal tissue to modulate biological functions and in vivo biofabrication of hybrid functional materials and devices.

    Place, publisher, year, edition, pages
    Elsevier, 2022
    Keywords
    polymerization, Bioelectronics interfaces, Conjugated oligomers, Model organism
    National Category
    Neurosciences
    Identifiers
    urn:nbn:se:liu:diva-181716 (URN)10.1016/j.bioactmat.2021.08.025 (DOI)000743377900002 ()34901533 (PubMedID)
    Note

    Funding agencies: European Unions Horizon 2020 research and innovation programme [800926]; Swedish Research CouncilSwedish Research CouncilEuropean Commission [VR-2017-04910]; Knut and Alice Wallenberg FoundationKnut & Alice Wallenberg Foundation; Swedish Foundation for Strategic Research (SSF)Swedish Foundation for Strategic Research; European Research Council (ERC)European Research Council (ERC)European Commission [834677]; Swedish Government Strategic Research Area in Materials Science on Advanced Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009-00971]; MultiPark - A Strategic Research Area at Lund University; MIURMinistry of Education, Universities and Research (MIUR) [SHARID - ARS01-01270]

    Available from: 2021-12-07 Created: 2021-12-07 Last updated: 2022-10-12Bibliographically approved
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  • 5.
    Abrahamsson, Tobias
    et al.
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Poxson, David
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Gabrielsson, Erik
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Sandberg, Mats
    RISE Acreo AB, Sweden.
    Simon, Daniel T
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Formation of Monolithic Ion-Selective Transport Media Based on "Click" Cross-Linked Hyperbranched Polyglycerol2019In: Frontiers in Chemistry, E-ISSN 2296-2646, Vol. 7, article id 484Article in journal (Refereed)
    Abstract [en]

    In the emerging field of organic bioelectronics, conducting polymers and ion-selective membranes are combined to form resistors, diodes, transistors, and circuits that transport and process both electronic and ionic signals. Such bioelectronics concepts have been explored in delivery devices that translate electronic addressing signals into the transport and dispensing of small charged biomolecules at high specificity and spatiotemporal resolution. Manufacturing such "iontronic" devices generally involves classical thin film processing of polyelectrolyte layers and insulators followed by application of electrolytes. This approach makes miniaturization and integration difficult, simply because the ion selective polyelectrolytes swell after completing the manufacturing. To advance such bioelectronics/iontronics and to enable applications where relatively larger molecules can be delivered, it is important to develop a versatile material system in which the charge/size selectivity can be easily tailormade at the same time enabling easy manufacturing of complex and miniaturized structures. Here, we report a one-pot synthesis approach with minimal amount of organic solvent to achieve cationic hyperbranched polyglycerol films for iontronics applications. The hyperbranched structure allows for tunable pre multi-functionalization, which combines available unsaturated groups used in crosslinking along with ionic groups for electrolytic properties, to achieve a one-step process when applied in devices for monolithic membrane gel formation with selective electrophoretic transport of molecules.

    Download full text (pdf)
    fulltext
  • 6.
    Abrahamsson, Tobias
    et al.
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Vagin, Mikhail
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Seitanidou, Maria S
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Roy, Arghyamalya
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Phopase, Jaywant
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Petsagkourakis, Ioannis
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Moro, Nathalie
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering. Empa, Switzerland.
    Tybrandt, Klas
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Crispin, Xavier
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Simon, Daniel
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Investigating the role of polymer size on ionic conductivity in free-standing hyperbranched polyelectrolyte membranes2021In: Polymer, ISSN 0032-3861, E-ISSN 1873-2291, Vol. 223, article id 123664Article in journal (Refereed)
    Abstract [en]

    Polymer-based ion exchange membranes (IEMs) are utilized for many applications such as in water desalination, energy storage, fuel cells and in electrophoretic drug delivery devices, exemplified by the organic electronic ion pump (OEIP). The bulk of current research is primarily focused on finding highly conductive and stable IEM materials. Even though great progress has been made, a lack of fundamental understanding of how specific polymer properties affect ionic transport capabilities still remains. This leads to uncertainty in how to proceed with synthetic approaches for designing better IEM materials. In this study, an investigation of the structure-property relationship between polymer size and ionic conductivity was performed by comparing a series of membranes, based on ionically charged hyperbranched polyglycerol of different polymer sizes. Observing an increase in ionic conductivity associated with increasing polymer size and greater electrolyte exclusion, indi-cating an ionic transportation phenomenon not exclusively based on membrane electrolyte uptake. These findings further our understanding of ion transport phenomena in semi-permeable membranes and indicate a strong starting point for future design and synthesis of IEM polymers to achieve broader capabilities for a variety of ion transport-based applications.

    Download full text (pdf)
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  • 7.
    Abramavicius, V.
    et al.
    Vilnius University, Lithuania; Centre Phys Science and Technology, Lithuania.
    Pranculis, V.
    Centre Phys Science and Technology, Lithuania.
    Melianas, Armantas
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Gulbinas, V.
    Centre Phys Science and Technology, Lithuania.
    Abramavicius, D.
    Vilnius University, Lithuania.
    Role of coherence and delocalization in photo-induced electron transfer at organic interfaces2016In: Scientific Reports, E-ISSN 2045-2322, Vol. 6, no 32914Article in journal (Refereed)
    Abstract [en]

    Photo-induced charge transfer at molecular heterojunctions has gained particular interest due to the development of organic solar cells (OSC) based on blends of electron donating and accepting materials. While charge transfer between donor and acceptor molecules can be described by Marcus theory, additional carrier delocalization and coherent propagation might play the dominant role. Here, we describe ultrafast charge separation at the interface of a conjugated polymer and an aggregate of the fullerene derivative PCBM using the stochastic Schrodinger equation (SSE) and reveal the complex time evolution of electron transfer, mediated by electronic coherence and delocalization. By fitting the model to ultrafast charge separation experiments, we estimate the extent of electron delocalization and establish the transition from coherent electron propagation to incoherent hopping. Our results indicate that even a relatively weak coupling between PCBM molecules is sufficient to facilitate electron delocalization and efficient charge separation at organic interfaces.

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  • 8.
    Abrikosov, Alexei I.
    et al.
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Science & Engineering.
    Veryazov, Valera
    Theoretical Chemistry, Lund University, Lund, Sweden.
    Multiscale Modelling of Atomistic Structure of Calcium Silicate Hydrate2022In: Solid State Phenomena, ISSN 1012-0394, E-ISSN 1662-9779, Solid State Phenomena, Vol. 338, p. 123-128Article in journal (Refereed)
    Abstract [en]

    The atomistic structure of calcium-silicate-hydrate (C-S-H) has been studied by applying force field simulations and quantum mechanical methods. Large number of crystallographically equivalent structures were used to account for the disordered nature of C-S-H. An extensive set of periodic structures of C-S-H (with a variation of chemical composition) has been generated and optimised. Special attention has been paid to two crystallographic models for tobermorite, which are used for the construction of C-S-H models. Re-optimisation of atomic structures, initially optimised with ReaxFF force field, by quantum chemical methods (semiempirical and Density functional theory) have been performed. Although the main structural characteristics of C-S-H remain the same in all calculations, the balance between the amount of OH groups and water in the structure is different. The obtained structures (optimised with a different level of theory) are combined into an on-line database and can be used for a future simulation of C-S-H materials.

  • 9.
    Abrikosov, Igor A.
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, Faculty of Science & Engineering.
    Alling, Björn
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Steneteg, Peter
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Science & Engineering.
    Hultberg, Lasse
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, Faculty of Science & Engineering.
    Hellman, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, Faculty of Science & Engineering.
    Yu Mosyagin, Igor
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, Faculty of Science & Engineering. Department of Theoretical Physics and Quantum Technologies, National Research, Technological University MISiS, Moscow, Russia.
    Lugovskoy, Andrey V.
    Department of Theoretical Physics and Quantum Technologies, National Research, Technological University MISiS, Russia.
    Barannikova, Svetlana A.
    Institute of Strength Physics and Materials Science, Siberian Branch of Russian Academy of Science, Tomsk, Russia; Department of Physics and Engineering, Tomsk State University, Tomsk, Russia.
    Finite Temperature, Magnetic, and Many-Body Effects in Ab Initio Simulations of Alloy Thermodynamics2013In: TMS2013 Supplemental Proceedings, John Wiley & Sons, 2013, p. 617-626Chapter in book (Refereed)
    Abstract [en]

    Ab initio electronic structure theory is known as a useful tool for prediction of materials properties. However, majority of simulations still deal with calculations in the framework of density functional theory with local or semi-local functionals carried out at zero temperature. We present new methodological solution.s, which go beyond this approach and explicitly take finite temperature, magnetic, and many-body effects into account. Considering Ti-based alloys, we discuss !imitations of the quasiharmonic approximation for the treatment of lattice vibrations, and present an accurate and easily extendable method to calculate free ,energies of strongly anharmonic solids. We underline the necessity to going beyond the state-of-the-art techniques for the determination of effective cluster interactions in systems exhibiting mctal-to-insulator transition, and describe a unified cluster expansion approach developed for this class of materials. Finally, we outline a first-principles method, disordered local moments molecular dynamics, for calculations of thermodynamic properties of magnetic alloys, like Cr1-x,.AlxN, in their high-temperature paramagnetic state. Our results unambiguously demonstrate importance of finite temperature effects in theoretical calculations ofthermodynamic properties ofmaterials.

  • 10. Order onlineBuy this publication >>
    Abrikossova, Natalia
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Investigation of nanoparticle-cell interactions for development of next generation of biocompatible MRI contrast agents2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Progress in synthesis technologies and advances in fundamental understanding of materials with low dimensionality has led to the birth of a new scientific field, nanoscience, and to strong expectations of multiple applications of nanomaterials. The physical properties of small particles are unique, bridging the gap between atoms and molecules, on one side, and bulk materials on the other side. The work presented in this thesis investigates the potential of using magnetic nanoparticles as the next generation of contrast agents for biomedical imaging. The focus is on gadolinium-based nanoparticles and cellular activity including the uptake, morphology and production of reactive oxygen species.

    Gd ion complexes, like Gd chelates, are used today in the clinic, world-wide. However, there is a need for novel agents, with improved contrast capabilities and increased biocompatibility. One avenue in their design is based on crystalline nanoparticles. It allows to reduce the total number of Gd ions needed for an examination. This can be done by nanotechnology, which allows one to improve and fine tune the physico- chemical properties on the nanomaterial in use, and to increase the number of Gd atoms at a specific site that interact with protons and thereby locally increase the signal. In the present work, synthesis, purification and surface modification of crystalline Gd2O3-based nanoparticles have been performed. The nanoparticles are selected on the basis of their physical properties, that is they show enhanced magnetic properties and therefore may be of high potential interest for applications as contrast agents.

    The main synthesis method of Gd2O3 nanoparticles in this work was the modified “polyol” route, followed by purification of as-synthesized DEG-Gd2O3 nanoparticles suspensions. In most cases the purification step involved dialysis of the nanoparticle samples. In this thesis, organosilane were chosen as an exchange agent for further functionalization. Moreover, several paths have been explored for modification of the nanoparticles, including Tb3+ doping and capping with sorbitol.

    Biocompatibility of the newly designed nanoparticles is a prerequisite for their use in medical applications. Its evaluation is a complex process involving a wide range of biological phenomena. A promising path adopted in this work is to study of nanoparticle interactions with isolated blood cells. In this way one could screen nanomaterial prior to animal studies.

    The primary cell type considered in the thesis are polymorphonuclear neutrophils (PMN) which represent a type of the cells of human blood belonging to the granulocyte family of leukocytes. PMNs act as the first defense of the immune system against invading pathogens, which makes them valuable for studies of biocompatibility of newly synthesized nanoparticles. In addition, an immortalized murine alveolar macrophage cell line (MH-S), THP-1 cell line, and Ba/F3 murine bone marrow-derived cell line were considered to investigate the optimization of the cell uptake and to examine the potential of new intracellular contrast agent for magnetic resonance imaging.

    In paper I, the nanoparticles were investigated in a cellular system, as potential probes for visualization and targeting intended for bioimaging applications. The production of reactive oxygen species (ROS) by means of luminol-dependent chemiluminescence from human neutrophils was studied in presence of Gd2O3 nanoparticles. In paper II, a new design of functionalized ultra-small rare earth-based nanoparticles was reported. The synthesis was done using polyol method followed by PEGylation, and dialysis. Supersmall gadolinium oxide (DEG-Gd2O3) nanoparticles, in the range of 3-5 nm were obtained and carefully characterized. Neutrophil activation after exposure to this nanomaterial was studied by means of fluorescence microscopy. In paper III, cell labeling with Gd2O3 nanoparticles in hematopoietic cells was monitored by magnetic resonance imaging (MRI). In paper IV, ultra-small gadolinium oxide nanoparticles doped with terbium ions were synthesized as a potentially bifunctional material with both fluorescent and magnetic contrast agent properties. Paramagnetic behavior was studied. MRI contrast enhancement was received, and the luminescent/ fluorescent property of the particles was attributable to the Tb3+ ion located on the crystal lattice of the Gd2O3 host. Fluorescent labeling of living cells was obtained. In manuscript V, neutrophil granulocytes were investigated with rapid cell signaling communicative processes in time frame of minutes, and their response to cerium-oxide based nanoparticles were monitored using capacitive sensors based on Lab-on-a-chip technology. This showed the potential of label free method used to measure oxidative stress of neutrophil granulocytes. In manuscript VI, investigations of cell-(DEGGd2O3) nanoparticle interactions were carried out. Plain (DEG-Gd2O3) nanoparticles, (DEG-Gd2O3) nanoparticles in presence of sorbitol and (DEG-Gd2O3) nanoparticles capped with sorbitol were studied. Relaxation studies and measurements of the reactive oxygen species production by neutrophils were based on chemiluminescence. Cell morphology was evaluated as a parameter of the nanoparticle induced inflammatory response by means of the fluorescence microscopy.

    The thesis demonstrates high potential of novel Gd2O3-based nanoparticles for development of the next generation contrast agents, that is to find biocompatible compounds with high relaxivity that can be detected at lower doses, and in the future enable targeting to provide great local contrast.

    List of papers
    1. Effects of gadolinium oxide nanoparticles on the oxidative burst from human neutrophil granulocytes
    Open this publication in new window or tab >>Effects of gadolinium oxide nanoparticles on the oxidative burst from human neutrophil granulocytes
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    2012 (English)In: Nanotechnology, ISSN 0957-4484, E-ISSN 1361-6528, Vol. 23, no 27, p. 275101-Article in journal (Refereed) Published
    Abstract [en]

    We have previously shown that gadolinium oxide (Gd2O3) nanoparticles are promising candidates to be used as contrast agents in magnetic resonance (MR) imaging applications. In this study, these nanoparticles were investigated in a cellular system, as possible probes for visualization and targeting intended for bioimaging applications. We evaluated the impact of the presence of Gd2O3 nanoparticles on the production of reactive oxygen species (ROS) from human neutrophils, by means of luminol-dependent chemiluminescence. Three sets of Gd2O3 nanoparticles were studied, i.e. as synthesized, dialyzed and both PEG-functionalized and dialyzed Gd2O3 nanoparticles. In addition, neutrophil morphology was evaluated by fluorescent staining of the actin cytoskeleton and fluorescence microscopy. We show that surface modification of these nanoparticles with polyethylene glycol (PEG) is essential in order to increase their biocompatibility. We observed that the as synthesized nanoparticles markedly decreased the ROS production from neutrophils challenged with prey (opsonized yeast particles) compared to controls without nanoparticles. After functionalization and dialysis, more moderate inhibitory effects were observed at a corresponding concentration of gadolinium. At lower gadolinium concentration the response was similar to that of the control cells. We suggest that the diethylene glycol (DEG) present in the as synthesized nanoparticle preparation is responsible for the inhibitory effects on the neutrophil oxidative burst. Indeed, in the present study we also show that even a low concentration of DEG, 0.3%, severely inhibits neutrophil function. In summary, the low cellular response upon PEG-functionalized Gd2O3 nanoparticle exposure indicates that these nanoparticles are promising candidates for MR-imaging purposes.

    Place, publisher, year, edition, pages
    Institute of Physics, 2012
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-79667 (URN)10.1088/0957-4484/23/27/275101 (DOI)000305802000001 ()
    Available from: 2012-08-14 Created: 2012-08-13 Last updated: 2022-02-07
    2. Synthesis and Characterization of PEGylated Gd2O3 Nanoparticles for MRI Contrast Enhancement
    Open this publication in new window or tab >>Synthesis and Characterization of PEGylated Gd2O3 Nanoparticles for MRI Contrast Enhancement
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    2010 (English)In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 26, no 8, p. 5753-5762Article in journal (Refereed) Published
    Abstract [en]

    Recently, much attention has been given to the development of biofunctionalized nanoparticles with magnetic properties for novel biomedical imaging. Guided, smart, targeting nanoparticulate magnetic resonance imaging (MRI) contrast agents inducing high MRI signal will be valuable tools for future tissue specific imaging and investigation of molecular and cellular events. In this study, we report a new design of functionalized ultrasmall rare earth based nanoparticles to be used as a positive contrast agent in MRI. The relaxivity is compared to commercially available Gd based chelates. The synthesis, PEGylation, and dialysis of small (3−5 nm) gadolinium oxide (DEG-Gd2O3) nanoparticles are presented. The chemical and physical properties of the nanomaterial were investigated with Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, and dynamic light scattering. Neutrophil activation after exposure to this nanomaterial was studied by means of fluorescence microscopy. The proton relaxation times as a function of dialysis time and functionalization were measured at 1.5 T. A capping procedure introducing stabilizing properties was designed and verified, and the dialysis effects were evaluated. A higher proton relaxivity was obtained for as-synthesized diethylene glycol (DEG)-Gd2O3 nanoparticles compared to commercial Gd-DTPA. A slight decrease of the relaxivity for as-synthesized DEG-Gd2O3 nanoparticles as a function of dialysis time was observed. The results for functionalized nanoparticles showed a considerable relaxivity increase for particles dialyzed extensively with r1 and r2 values approximately 4 times the corresponding values for Gd-DTPA. The microscopy study showed that PEGylated nanoparticles do not activate neutrophils in contrast to uncapped Gd2O3. Finally, the nanoparticles are equipped with Rhodamine to show that our PEGylated nanoparticles are available for further coupling chemistry, and thus prepared for targeting purposes. The long term goal is to design a powerful, directed contrast agent for MRI examinations with specific targeting possibilities and with properties inducing local contrast, that is, an extremely high MR signal at the cellular and molecular level.

    Place, publisher, year, edition, pages
    American Chemical Society (ACS), 2010
    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:liu:diva-54946 (URN)10.1021/la903566y (DOI)000276562300061 ()
    Available from: 2010-04-23 Created: 2010-04-23 Last updated: 2022-02-07Bibliographically approved
    3. Gd2O3 nanoparticles in hematopoietic cells for MRI contrast enhancement
    Open this publication in new window or tab >>Gd2O3 nanoparticles in hematopoietic cells for MRI contrast enhancement
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    2011 (English)In: International journal of nano medicine, ISSN 1178-2013, Vol. 6, p. 3233-3240Article in journal (Refereed) Published
    Abstract [en]

    As the utility of magnetic resonance imaging (MRI) broadens, the importance of having specific and efficient contrast agents increases and in recent time there has been a huge development in the fields of molecular imaging and intracellular markers. Previous studies have shown that gadolinium oxide (Gd2O3) nanoparticles generate higher relaxivity than currently available Gd chelates: In addition, the Gd2O3 nanoparticles have promising properties for MRI cell tracking. The aim of the present work was to study cell labeling with Gd2O3 nanoparticles in hematopoietic cells and to improve techniques for monitoring hematopoietic stem cell migration by MRI. Particle uptake was studied in two cell lines: the hematopoietic progenitor cell line Ba/F3 and the monocytic cell line THP-1. Cells were incubated with Gd2O3 nanoparticles and it was investigated whether the transfection agent protamine sulfate increased the particle uptake. Treated cells were examined by electron microscopy and MRI, and analyzed for particle content by inductively coupled plasma sector field mass spectrometry. Results showed that particles were intracellular, however, sparsely in Ba/F3. The relaxation times were shortened with increasing particle concentration. Relaxivities, r1 and r2 at 1.5 T and 21°C, for Gd2O3 nanoparticles in different cell samples were 3.6–5.3 s-1 mM-1 and 9.6–17.2 s-1 mM-1, respectively. Protamine sulfate treatment increased the uptake in both Ba/F3 cells and THP-1 cells. However, the increased uptake did not increase the relaxation rate for THP-1 as for Ba/F3, probably due to aggregation and/or saturation effects. Viability of treated cells was not significantly decreased and thus, it was concluded that the use of Gd2O3 nanoparticles is suitable for this type of cell labeling by means of detecting and monitoring hematopoietic cells. In conclusion, Gd2O3 nanoparticles are a promising material to achieve positive intracellular MRI contrast; however, further particle development needs to be performed.

    Place, publisher, year, edition, pages
    Manchester, UK: Dove Medical Press Ltd, 2011
    Keywords
    gadolinium oxide, magnetic resonance imaging, contrast agent, cell labeling, Ba/F3 cells, THP-1 cells
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-72275 (URN)10.2147/IJN.S23940 (DOI)000298164300001 ()
    Note

    funding agencies|Swedish Research Council| 621-2007-3810 621-2009-5148 521-2009-3423 |VINNOVA| 2009-00194 |Center in Nanoscience and Technology at LiTH (CeNano)||

    Available from: 2011-11-24 Created: 2011-11-24 Last updated: 2021-10-13
    4. Synthesis and Characterization of Tb3+-Doped Gd2O3 Nanocrystals: A Bifunctional Material with Combined Fluorescent Labeling and MRI Contrast Agent Properties
    Open this publication in new window or tab >>Synthesis and Characterization of Tb3+-Doped Gd2O3 Nanocrystals: A Bifunctional Material with Combined Fluorescent Labeling and MRI Contrast Agent Properties
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    2009 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 113, no 17, p. 6913-6920Article in journal (Refereed) Published
    Abstract [en]

    Ultrasmall gadolinium oxide nanoparticles doped with terbium ions were synthesized by the polyol route and characterized as a potentially bifunctional material with both fluorescent and magnetic contrast agent properties. The structural, optical, and magnetic properties of the organic-acid-capped and PEGylated Gd2O3:Tb3+ nanocrystals were studied by HR-TEM, XPS, EDX, IR, PL, and SQUID. The luminescent/fluorescent property of the particles is attributable to the Tb3+ ion located on the crystal lattice of the Gd2O3 host. The paramagnetic behavior of the particles is discussed. Pilot studies investigating the capability of the nanoparticles for fluorescent labeling of living cells and as a MRI contrast agent were also performed. Cells of two cell lines (THP-1 cells and fibroblasts) were incubated with the particles, and intracellular particle distribution was visualized by confocal microscopy. The MRI relaxivity of the PEGylated nanoparticles in water at low Gd concentration was assessed showing a higher T-1 relaxation rate compared to conventional Gd-DTPA chelates and comparable to that of undoped Gd2O3 nanoparticles.

    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:liu:diva-12944 (URN)10.1021/jp808708m (DOI)000265529700009 ()
    Note

    On the day of the defence date the status of this article was Submitted

    Available from: 2008-02-21 Created: 2008-02-21 Last updated: 2021-10-13Bibliographically approved
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    Investigation of nanoparticle-cell interactions for development of next generation of biocompatible MRI contrast agents
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  • 11.
    Abutalib, M. M.
    et al.
    Univ Jeddah, Saudi Arabia.
    Alghamdi, Haifa Mohammed
    Univ Jeddah, Saudi Arabia.
    Rajeh, A.
    Amran Univ, Yemen.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, Faculty of Science & Engineering.
    Hezma, A. M.
    Natl Res Ctr, Egypt.
    Mannaa, Mohammed A.
    Amran Univ, Yemen.
    Fe3O4/Co3O4-TiO2 S-scheme photocatalyst for degradation of organic pollutants and H-2 production under natural sunlight2022In: Journal of Materials Research and Technology, ISSN 2238-7854, Vol. 20, p. 1043-1056Article in journal (Refereed)
    Abstract [en]

    Sunlight responsible mono-and co-doped TiO2 nanoparticles (Con+ and Fen+) were prepared via sol-gel technique. The X-ray diffraction (XRD) results showed no phase change of TiO2 was observed after the addition of Con+ and Fen+ ions. Diffuse reflectance spectra (DRS) results showed a significant red-shift of the absorption edge after doping TiO2 by Co(n )and Fen+ and the band gap energy reduced sharply from 3.10 to 1.72 eV. X-ray photoelectron spectroscopy (XPS) results emphasized the existence of multivalent states of Co2+, Co3+, Fe2+ and Fe3+. The results of ultraviolet photoelectron spectroscopy (UPS), work function, electron spin resonance (ESR) illustrated the Fe3O4/Co3O4-TiO2 formed of ternary hetero-junctions. The photocatalytic performance of the prepared photocatalysts was determined for photodegradation of tetracycline (TC) and phenol (Pl) and production of hydrogen. The results illustrated the existence of multivalent states of Fe and Co ions (Co2+, Co3+, Fe2+ and Fe3+) together improved the solar light absorption, inhibited the recombination of photo -generated charges and consequently enhanced the photocatalytic efficiency of TiO2 compared with mono-doped TiO2 (Co3O4/TiO2 and Fe3O4/TiO2). The sample with 5%Fe3O4/ Co(3)O(4)4-TiO2 showed the highest photoactivity. The mineralization (TOC), photodegradation mechanism and reusability of prepared photocatalysts were also studied. The Fe3O4/Co3O4-TiO2 nanoparticles showed high photoactivity and stability and can be adopted as a promising materials for different environmental and H-2 production applications. (C) 2022 The Author(s). Published by Elsevier B.V.

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    fulltext
  • 12.
    Abutalib, M. M.
    et al.
    Univ Jeddah, Saudi Arabia.
    Alghamdi, Haifa Mohammed
    Univ Jeddah, Saudi Arabia.
    Rajeh, A.
    Amran Univ, Yemen.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, Faculty of Science & Engineering.
    Hezmad, A. M.
    Natl Res Ctr, Egypt.
    Mannaa, Mohammed A.
    Amran Univ, Yemen.
    Preparation of rGO/FeMoO4 as high-performance photocatalyst for degradation of malachite green, phenol and H2 evolution under natural sunlight2022In: International journal of hydrogen energy, ISSN 0360-3199, E-ISSN 1879-3487, Vol. 47, no 77, p. 32955-32968Article in journal (Refereed)
    Abstract [en]

    FeMoO4 and rGO/FeMoO4 nanocomposites were successfully prepared by a facile hydro-thermal method. The XRD results confirmed that the FeMoO4 has a monometallic b-FeMoO4 crystalline phase while the rGO/FeMoO4 showed both monometallic a-and b-FeMoO4 phases where b-FeMoO4 is the predominant phase. The reduction of graphene oxide (GO) to reduced graphene oxide (rGO) was performed without using any chemical reductions. UV-Vis results showed that the visible light absorption and band gap energy were enhanced after the addition of rGO. The prepared samples were successfully applied for degradation of malachite green (MG) and phenol (Ph) and for H2 evolution under natural solar light irradiation. All the nanocomposites showed higher photocatalytic activities compared with pure FeMoO4 photocatalyst, and the 10%rGO/FeMoO4 gave the highest photodegradation performance for MG and Ph and for H2 evolution. The photodegradation results revealed that the rGO content played the crucial factor in the photodegradation of MG and Ph, and H2 evolution. The mineralization (TOC), photodegradation mechanism and degradation kinetics of MG and Ph were discussed.

    The full text will be freely available from 2024-08-19 09:27
  • 13. Order onlineBuy this publication >>
    Adam, Rania Elhadi
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, Faculty of Science & Engineering.
    Synthesis and Characterization of Some Nanostructured Materials for Visible Light-driven Photo Processes2020Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Nanostructured materials for visible light driven photo-processes such as photodegradation of organic pollutants and photoelectrochemical (PEC) water oxidation for hydrogen production are very attractive because of the positive impact on the environment. Metal oxides-based nanostructures are widely used in these photoprocesses due to their unique properties. But single nanostructured metal oxide material might suffer from low efficiency and instability in aqueous solutions under visible light. These facts make it important to have an efficient and reliable nanocomposite for the photo-processes. The combination of different nanomaterials to form a composite configuration can produce a material with new properties. The new properties which are due to the synergetic effect, are a combination of the properties of all the counterparts of the nanocomposite. Zinc oxides (ZnO) have unique optical and electrical properties which grant it to be used in optoelectronics, sensors, solar cells, nanogenerators, and photocatalysis activities. Although ZnO absorbs visible light from the sun due to the deep level band, it mainly absorbs ultraviolet wavelengths which constitute a small portion of the whole solar spectrum range. Also, ZnO has a problem with the high recombination rate of the photogenerated electrons. These problems might reduce its applicability to the photo-process. Therefore, our aim is to develop and investigate different nanocomposites materials based on the ZnO nanostructures for the enhancement of photocatalysis processes using the visible solar light as a green source of energy. Two photo-processes were applied to examine the developed nanocomposites through photocatalysis: (1) the photodegradation of organic dyes, (2) PEC water splitting. In the first photo-process, we used the ZnO nanoparticles (NPs), Magnesium (Mg)-doped ZnO NPs, and plasmonic ZnO/graphene-based nanocomposite for the decomposition of some organic dyes that have been used in industries. For the second photo-process, ZnO photoelectrode composite with different silver-based semiconductors to enhance the performance of the ZnO photoelectrode was used for PEC reaction analysis to perform water splitting. The characterization and photocatalysis experiment results showed remarkable enhancement in the photocatalysis efficiency of the synthesized nanocomposites. The observed improved properties of the ZnO are due to the synergetic effects are caused by the addition of the other nanomaterials. Hence, the present thesis attends to the synthesis and characterization of some nanostructured materials composite with ZnO that are promising candidates for visible light-driven photo-processes.  

    List of papers
    1. Synthesis of ZnO nanoparticles by co-precipitation method for solar driven photodegradation of Congo red dye at different pH
    Open this publication in new window or tab >>Synthesis of ZnO nanoparticles by co-precipitation method for solar driven photodegradation of Congo red dye at different pH
    2018 (English)In: PHOTONICS AND NANOSTRUCTURES-FUNDAMENTALS AND APPLICATIONS, ISSN 1569-4410, Vol. 32, p. 11-18Article in journal (Refereed) Published
    Abstract [en]

    Solar driven photocatalytic processes to remove organic pollutants from wastewater and other aqueous solutions is very important and useful due to its environmental benefits regarding sustainability aspect. In this article, we report a study on the use of bare zinc oxide (ZnO) nanoparticles (NPs) prepared by the chemical low temperature co-precipitation method and used as a catalyst to degrade the Congo red dye from aqueous solution using solar radiation. We performed the photocatalytic experiments for degradation of Congo red dye under solar radiation at different pH values. The results showed that the ZnO NPs are effective under solar radiation for degradation of Congo red dye. Even when the pH was varied down to 4 or raised to 10, the degradation was observed to be slightly improved. This result is due to the excess of radicals species, which enhance the photocatalytic process. In general, the observed degradation efficiency of the ZnO NPs is due to the deep level defects within the band gap that were introduced during the growth process of the ZnO NPs, which enhance the absorption wavelength band towards the visible light region. Recycling of the ZnO NPs for 3 successive runs have indicated the feasibility of reusing the NPs for several times. This implies that by using bare ZnO NPs an efficient approach for degradation of toxic waste can be achieved. Radical scavengers were used to evaluate the role of the radicals in the reaction mechanism.

    Place, publisher, year, edition, pages
    ELSEVIER SCIENCE BV, 2018
    Keywords
    ZnO nanoparticles; Point defects; Photocatalytic
    National Category
    Atom and Molecular Physics and Optics
    Identifiers
    urn:nbn:se:liu:diva-153525 (URN)10.1016/j.photonics.2018.08.005 (DOI)000451653700003 ()
    Note

    Funding Agencies|department of Science and Technology, Linkoping University, Sweden

    Available from: 2018-12-20 Created: 2018-12-20 Last updated: 2024-01-08
    2. Synthesis of Mg-doped ZnO NPs via a chemical low-temperature method and investigation of the efficient photocatalytic activity for the degradation of dyes under solar light
    Open this publication in new window or tab >>Synthesis of Mg-doped ZnO NPs via a chemical low-temperature method and investigation of the efficient photocatalytic activity for the degradation of dyes under solar light
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    2020 (English)In: Solid State Sciences, ISSN 1293-2558, E-ISSN 1873-3085, Vol. 99, article id 106053Article in journal (Refereed) Published
    Abstract [en]

    Doped semiconductors nanostructures (NSs) have shown great interest as a potential for green and efficient photocatalysis activities. Magnesium (Mg)-doped zinc oxide (ZnO) nanoparticles (NPs) has been synthesized by a one-step chemical low temperature (60 °C) co-precipitation method without further calcination and their photocatalytic performance for photodegradation of Methylene blue (MB) dye under the illumination of solar light is investigated. The crystal structure of the synthesized NPs is examined by X-ray diffraction (XRD). XRD data indicates a slight shift towards higher 2θ angle in Mg-doped samples as compared to the pure ZnO NPs which suggest the incorporation of Mg2+ into ZnO crystal lattice. X-ray photoelectron spectroscopy (XPS), UV–Vis spectrophotometer and cathodoluminescence (CL) spectroscopy, were used to study electronics, and optical properties, respectively. The XPS analysis confirms the substitution of the Zn2+ by the Mg2+ into the ZnO crystal lattice in agreement with the XRD data. The photocatalytic activities showed a significant enhancement of the Mg-doped ZnO NPs in comparison with pure ZnO NPs. Hole/radical scavengers were used to reveal the mechanism of the photodegradation. It was found that the addition of the Mg to the ZnO lattices increases the absorption of the hydroxyl ions at the surface of the NPs and hence acts as a trap site leading to decrease the electron-hole pair and consequently enhancing the photodegradation.

    Place, publisher, year, edition, pages
    Elsevier, 2020
    Keywords
    ZnO nanoparticles, Mg-doped ZnO NPs, Photocatalytic, Photodegradation, Methylene blue, Congo red
    National Category
    Materials Chemistry
    Identifiers
    urn:nbn:se:liu:diva-164333 (URN)10.1016/j.solidstatesciences.2019.106053 (DOI)000516720100024 ()2-s2.0-85074706430 (Scopus ID)
    Available from: 2020-03-18 Created: 2020-03-18 Last updated: 2024-01-08Bibliographically approved
    3. Graphene-based plasmonic nanocomposites for highly enhanced solar-driven photocatalytic activities
    Open this publication in new window or tab >>Graphene-based plasmonic nanocomposites for highly enhanced solar-driven photocatalytic activities
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    2019 (English)In: RSC Advances, E-ISSN 2046-2069, Vol. 9, no 52, p. 30585-30598Article in journal (Refereed) Published
    Abstract [en]

    High-efficiency photocatalysts are crucial for the removal of organic pollutants and environmental sustainability. In the present work, we report on a new low-temperature hydrothermal chemical method, assisted by ultrasonication, to synthesize disruptive plasmonic ZnO/graphene/Ag/AgI nanocomposites for solar-driven photocatalysis. The plasmonic nanocomposites were investigated by a wide range of characterization techniques, confirming successful formation of photocatalysts with excellent degradation efficiency. Using Congo red as a model dye molecule, our experimental results demonstrated a photocatalytic reactivity exceeding 90% efficiency after one hour simulated solar irradiation. The significantly enhanced degradation efficiency is attributed to improved electronic properties of the nanocomposites by hybridization of the graphene and to the addition of Ag/AgI which generates a strong surface plasmon resonance effect in the metallic silver further improving the photocatalytic activity and stability under solar irradiation. Scavenger experiments suggest that superoxide and hydroxyl radicals are responsible for the photodegradation of Congo red. Our findings are important for the fundamental understanding of the photocatalytic mechanism of ZnO/graphene/Ag/AgI nanocomposites and can lead to further development of novel efficient photocatalyst materials.

    Place, publisher, year, edition, pages
    Royal Meteorological Society, 2019
    National Category
    Condensed Matter Physics
    Identifiers
    urn:nbn:se:liu:diva-160568 (URN)10.1039/C9RA06273D (DOI)000487989300064 ()
    Note

    Funding agencies: Department of Science and Technology (ITN) at Campus Norrkoping, Linkoping University, Sweden; Knut and Alice Wallenberg FoundationKnut & Alice Wallenberg Foundation

    Available from: 2019-09-30 Created: 2019-09-30 Last updated: 2024-01-08Bibliographically approved
    4. n–n ZnO–Ag2CrO4 heterojunction photoelectrodes with enhanced visible-light photoelectrochemical properties
    Open this publication in new window or tab >>n–n ZnO–Ag2CrO4 heterojunction photoelectrodes with enhanced visible-light photoelectrochemical properties
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    2019 (English)In: RSC Advances, E-ISSN 2046-2069, Vol. 9, no 14, p. 7992-8001Article in journal (Refereed) Published
    Abstract [en]

    In this study, ZnO nanorods (NRs) were hydrothermally grown on an Au-coated glass substrate at a relatively low temperature (90 °C), followed by the deposition of Ag2CrO4 particles via a successive ionic layer adsorption and reaction (SILAR) route. The content of the Ag2CrO4 particles on ZnO NRs was controlled by changing the number of SILAR cycles. The fabricated ZnO–Ag2CrO4 heterojunction photoelectrodes were subjected to morphological, structural, compositional, and optical property analyses; their photoelectrochemical (PEC) properties were investigated under simulated solar light illumination. The photocurrent responses confirmed that the ability of the ZnO–Ag2CrO4 heterojunction photoelectrodes to separate the photo-generated electron–hole pairs is stronger than that of bare ZnO NRs. Impressively, the maximum photocurrent density of about 2.51 mA cm−2 at 1.23 V (vs. Ag/AgCl) was measured for the prepared ZnO–Ag2CrO4 photoelectrode with 8 SILAR cycles (denoted as ZnO–Ag2CrO4-8), which exhibited about 3-fold photo-enhancement in the current density as compared to bare ZnO NRs (0.87 mA cm−2) under similar conditions. The improvement in photoactivity was attributed to the ideal band gap and high absorption coefficient of the Ag2CrO4 particles, which resulted in improved solar light absorption properties. Furthermore, an appropriate annealing treatment was proven to be an efficient process to increase the crystallinity of Ag2CrO4 particles deposited on ZnO NRs, which improved the charge transport characteristics of the ZnO–Ag2CrO4-8 photoelectrode annealed at 200 °C and increased the performance of the photoelectrode. The results achieved in the present work present new insights for designing n–n heterojunction photoelectrodes for efficient and cost-effective PEC applications and solar-to-fuel energ

    Place, publisher, year, edition, pages
    Royal Society of Chemistry, 2019
    National Category
    Physical Sciences
    Identifiers
    urn:nbn:se:liu:diva-155657 (URN)10.1039/C9RA00639G (DOI)000462646000051 ()2-s2.0-85062919263 (Scopus ID)
    Note

    Funding agencies: University of Mohaghegh Ardabili-Iran and Linkoping University-Sweden; AForsk [17-457

    Available from: 2019-03-22 Created: 2019-03-22 Last updated: 2024-01-08Bibliographically approved
    5. ZnO/Ag/Ag2WO4 photo-electrodes with plasmonic behavior for enhanced photoelectrochemical water oxidation
    Open this publication in new window or tab >>ZnO/Ag/Ag2WO4 photo-electrodes with plasmonic behavior for enhanced photoelectrochemical water oxidation
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    2019 (English)In: RSC Advances, E-ISSN 2046-2069, Vol. 9, no 15, p. 8271-8279Article in journal (Refereed) Published
    Abstract [en]

    Ag-based compounds are excellent co-catalyst that can enhance harvesting visible light and increase photo-generated charge carrier separation owing to its surface plasmon resonance (SPR) effect in photoelectrochemical (PEC) applications. However, the PEC performance of a ZnO/Ag/Ag2WO4 heterostructure with SPR behavior has not been fully studied so far. Here we report the preparation of a ZnO/Ag/Ag2WO4 photo-electrode with SPR behavior by a low temperature hydrothermal chemical growth method followed by a successive ionic layer adsorption and reaction (SILAR) method. The properties of the prepared samples were investigated by different characterization techniques, which confirm that Ag/Ag2WO4 was deposited on the ZnO NRs. The Ag2WO4/Ag/ZnO photo-electrode showed an enhancement in PEC performance compared to bare ZnO NRs. The observed enhancement is attributed to the red shift of the optical absorption spectrum of the Ag2WO4/Ag/ZnO to the visible region (>400 nm) and to the SPR effect of surface metallic silver (Ag0) particles from the Ag/Ag2WO4 that could generate electron–hole pairs under illumination of low energy visible sun light. Finally, we proposed the PEC mechanism of the Ag2WO4/Ag/ZnO photo-electrode with an energy band structure and possible electron–hole separation and transportation in the ZnO/Ag/Ag2WO4 heterostructure with SPR effect for water oxidation. ER

    Place, publisher, year, edition, pages
    Royal Society of Chemistry, 2019
    National Category
    Physical Sciences
    Identifiers
    urn:nbn:se:liu:diva-155655 (URN)10.1039/C8RA10141H (DOI)000461445300016 ()
    Available from: 2019-03-22 Created: 2019-03-22 Last updated: 2024-01-08Bibliographically approved
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  • 14.
    Adam, Rania Elhadi
    et al.
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, Faculty of Science & Engineering.
    Alnoor, Hatim
    Linköping University, Department of Science and Technology. Linköping University, Faculty of Science & Engineering.
    Pozina, Galia
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Liu, Xianjie
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Willander, Magnus
    Linköping University, Faculty of Science & Engineering. Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics.
    Nur, Omer
    Linköping University, Faculty of Science & Engineering. Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics.
    Synthesis of Mg-doped ZnO NPs via a chemical low-temperature method and investigation of the efficient photocatalytic activity for the degradation of dyes under solar light2020In: Solid State Sciences, ISSN 1293-2558, E-ISSN 1873-3085, Vol. 99, article id 106053Article in journal (Refereed)
    Abstract [en]

    Doped semiconductors nanostructures (NSs) have shown great interest as a potential for green and efficient photocatalysis activities. Magnesium (Mg)-doped zinc oxide (ZnO) nanoparticles (NPs) has been synthesized by a one-step chemical low temperature (60 °C) co-precipitation method without further calcination and their photocatalytic performance for photodegradation of Methylene blue (MB) dye under the illumination of solar light is investigated. The crystal structure of the synthesized NPs is examined by X-ray diffraction (XRD). XRD data indicates a slight shift towards higher 2θ angle in Mg-doped samples as compared to the pure ZnO NPs which suggest the incorporation of Mg2+ into ZnO crystal lattice. X-ray photoelectron spectroscopy (XPS), UV–Vis spectrophotometer and cathodoluminescence (CL) spectroscopy, were used to study electronics, and optical properties, respectively. The XPS analysis confirms the substitution of the Zn2+ by the Mg2+ into the ZnO crystal lattice in agreement with the XRD data. The photocatalytic activities showed a significant enhancement of the Mg-doped ZnO NPs in comparison with pure ZnO NPs. Hole/radical scavengers were used to reveal the mechanism of the photodegradation. It was found that the addition of the Mg to the ZnO lattices increases the absorption of the hydroxyl ions at the surface of the NPs and hence acts as a trap site leading to decrease the electron-hole pair and consequently enhancing the photodegradation.

  • 15.
    Adam, Stefan
    et al.
    Leibniz Institute Polymerforsch eV, Germany; Technical University of Dresden, Germany.
    Koenig, Meike
    Leibniz Institute Polymerforsch eV, Germany; Technical University of Dresden, Germany; Karlsruhe Institute Technology, Germany.
    Rodenhausen, Keith Brian
    University of Nebraska, NE 68588 USA; Biolin Science Inc, NJ 07652 USA.
    Eichhorn, Klaus-Jochen
    Leibniz Institute Polymerforsch eV, Germany.
    Oertel, Ulrich
    Leibniz Institute Polymerforsch eV, Germany.
    Schubert, Mathias
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering. Leibniz Institute Polymerforsch eV, Germany; University of Nebraska, NE 68588 USA; University of Nebraska, NE 68588 USA.
    Stamm, Manfred
    Leibniz Institute Polymerforsch eV, Germany; Technical University of Dresden, Germany.
    Uhlmann, Petra
    Leibniz Institute Polymerforsch eV, Germany; University of Nebraska, NE 68588 USA.
    Quartz crystal microbalance with coupled Spectroscopic Ellipsometry-study of temperature-responsive polymer brush systems2017In: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 421, p. 843-851Article in journal (Refereed)
    Abstract [en]

    Using a combined setup of quartz crystal microbalance with dissipation monitoring together with spectroscopic ellipsometry, the thermo-responsive behavior of two different brush systems (poly(N-isopropyl acrylamide) and poly(2-oxazoline)s) was investigated and compared to the behavior of the free polymer in solution. Poly(2-oxazoline)s with three different hydrophilicities were prepared by changing the content of a hydrophilic comonomer. While both polymer types exhibit a sharp, discontinuous thermal transition in solution, in the brush state the transition gets broader in the case of poly(N-isopropyl acrylamide) and is transformed into a continuous transition for poly(2-oxazoline)s. The position of the transition in solution is influenced by the degree of hydrophilicity of the poly(2-oxazoline). The difference in areal mass detected by quartz crystal microbalance and by spectroscopic ellipsometry, has been attributed to the chain segment density profile of the polymer brushes. Applying this density profile information, for poly(N-isopropyl acrylamide) two different swelling stages could be identified, while for poly(2-oxazoline) the transition between a parabolic and more step-wise profile is found continuous. The different swelling characteristics were attributed to the different miscibility behavior types, with the brush state acting similar to a crosslinked system. (C) 2017 Elsevier B.V. All rights reserved.

  • 16.
    Adranno, Brando
    et al.
    Stockholm Univ, Sweden.
    Renier, Olivier
    Stockholm Univ, Sweden.
    Bousrez, Guillaume
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering. Stockholm Univ, Sweden.
    Paterlini, Veronica
    Stockholm Univ, Sweden.
    Baryshnikov, Glib
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Smetana, Volodymyr
    Stockholm Univ, Sweden.
    Tang, Shi
    Umea Univ, Sweden.
    agren, Hans
    Uppsala Univ, Sweden.
    Metlen, Andreas
    Queens Univ Belfast, North Ireland.
    Edman, Ludvig
    Umea Univ, Sweden.
    Anja-Verena, Mudring
    Stockholm Univ, Sweden; Aarhus Univ, Denmark.
    Rogers, Robin D.
    Stockholm Univ, Sweden; Queens Univ Belfast, North Ireland; Univ Alabama, AL 35487 USA.
    The 8-Hydroxyquinolinium Cation as a Lead Structure for Efficient Color-Tunable Ionic Small Molecule Emitting Materials2023In: ADVANCED PHOTONICS RESEARCH, ISSN 2699-9293, Vol. 4, no 3, article id 2200279Article in journal (Refereed)
    Abstract [en]

    Albeit tris(8-hydroxyquinolinato) aluminum (Alq(3)) and its derivatives are prominent emitter materials for organic lighting devices, and the optical transitions occur among ligand-centered states, the use of metal-free 8-hydroxyquinoline is impractical as it suffers from strong nonradiative quenching, mainly through fast proton transfer. Herein, it is shown that the problem of rapid proton exchange and vibration quenching of light emission can be overcome not only by complexation, but also by organization of the 8-hydroxyquinolinium cations into a solid rigid network with appropriate counter-anions (here bis(trifluoromethanesulfonyl)imide). The resulting structure is stiffened by secondary bonding interactions such as pi-stacking and hydrogen bonds, which efficiently block rapid proton transfer quenching and reduce vibrational deactivation. Additionally, the optical properties are tuned through methyl substitution from deep blue (455 nm) to blue-green (488 nm). Time-dependent density functional theory (TDFT) calculations reveal the emission to occur from which an unexpectedly long-lived S-1 level, unusual for organic fluorophores. All compounds show comparable, even superior photoluminescence compared to Alq(3) and related materials, both as solids and thin films with quantum yields (QYs) up to 40-50%. In addition, all compounds show appreciable thermal stability with decomposition temperatures above 310 degrees C.

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  • 17.
    Aftab, Umair
    et al.
    Mehran Univ Engn & Technol, Pakistan.
    Tahira, Aneela
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, Faculty of Science & Engineering.
    Gradone, Alessandro
    CNR IMM, Italy; Univ Bologna, Italy.
    Morandi, Vittorio
    CNR IMM, Italy.
    Abro, Muhammad Ishaq
    Mehran Univ Engn & Technol, Pakistan.
    Baloch, Muhammad Moazam
    Mehran Univ Engn & Technol, Pakistan.
    Bhatti, Adeel Liaquat
    Univ Sindh, Pakistan.
    Nafady, Ayman
    King Saud Univ, Saudi Arabia.
    Vomiero, Alberto
    Lulea Univ Technol, Sweden; Ca Foscari Univ Venice, Italy.
    Ibupoto, Zafar Hussain
    Univ Sindh, Pakistan.
    Two step synthesis of TiO2-Co3O4 composite for efficient oxygen evolution reaction2021In: International journal of hydrogen energy, ISSN 0360-3199, E-ISSN 1879-3487, Vol. 46, no 13, p. 9110-9122Article in journal (Refereed)
    Abstract [en]

    For an active hydrogen gas generation through water dissociation, the sluggish oxygen evolution reaction (OER) kinetics due to large overpotential is a main hindrance. Herein, a simple approach is used to produce composite material based on TiO2/Co3O4 for efficient OER and overpotential is linearly reduced with increasing amount of TiO2. The scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM) investigations reveal the wire like morphology of composite materials, formed by the self-assembly of nanoparticles. The titania nanoparticles were homogenously distributed on the larger Co3O4 nanoparticles. The powder x-ray diffraction revealed a tetragonal phase of TiO2 and the cubic phase of Co3O4 in the composite materials. Composite samples with increasing TiO2 content were obtained (18%, 33%, 41% and 65% wt.). Among the composites, cobalt oxide-titanium oxide with the highest TiO2 content (CT-20) possesses the lowest overpotential for OER with a Tafel slope of 60 mV dec(-1) and an exchange current density of 2.98 x 10(-3)A/cm(2). The CT-20 is highly durable for 45 h at different current densities of 10, 20 and 30 mA/cm(2). Electrochemical impedance spectroscopy (EIS) confirmed the fast charge transport for the CT-20 sample, which potentially accelerated the OER kinetics. These results based on a two-step methodology for the synthesis of TiO2/Co3O4 material can be useful and interesting for various energy storage and energy conversion systems. (C) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

  • 18.
    Aftab, Umair
    et al.
    Mehran Univ Engn and Technol, Pakistan.
    Tahira, Aneela
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, Faculty of Science & Engineering.
    Mazzaro, Raffaello
    Italian Natl Res Council, Italy.
    Abro, Muhammad Ishaq
    Mehran Univ Engn and Technol, Pakistan.
    Baloch, Muhammad Moazam
    Mehran Univ Engn and Technol, Pakistan.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, Faculty of Science & Engineering.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, Faculty of Science & Engineering.
    Yu, Cong
    Chinese Acad Sci, Peoples R China.
    Ibupoto, Zafar Hussain
    Univ Sindh, Pakistan.
    The chemically reduced CuO-Co3O4 composite as a highly efficient electrocatalyst for oxygen evolution reaction in alkaline media2019In: Catalysis Science & Technology, ISSN 2044-4753, E-ISSN 2044-4761, Vol. 9, no 22, p. 6274-6284Article in journal (Refereed)
    Abstract [en]

    The fabrication of efficient, alkaline-stable and nonprecious electrocatalysts for the oxygen evolution reaction is highly needed; however, it is a challenging task. Herein, we report a noble metal-free advanced catalyst, i.e. the chemically reduced mixed transition metal oxide CuO-Co3O4 composite, with outstanding oxygen evolution reaction activity in alkaline media. Sodium borohydride (NaBH4) was used as a reducing agent for the mixed transition metal oxide CuO-Co3O4. The chemically reduced composite carried mixed valence states of Cu and Co, which played a dynamic role in driving an excellent oxygen evolution reaction process. The X-ray photo-electron spectroscopy (XPS) study confirmed high density of active sites in the treated sample with a large number of oxygen vacancies. The developed electrocatalyst showed the lowest overpotential of 144.5 mV vs. the reversible hydrogen electrode (RHE) to achieve the current density of 40 mA cm(-2) and remained stable for 40 hours throughout the chronoamperometry test at the constant potential of 1.39 V vs. RHE. Moreover, the chemically reduced composite was highly durable. Electrochemical impedance spectroscopy (EIS) confirmed the low charge transfer resistance of 13.53 ohms for the chemically reduced composite, which was 50 and 26 times smaller than that of Co3O4 and untreated CuO-Co3O4, respectively. The electrochemically active surface area for the chemically reduced composite was found to be greater than that for pristine CuO, Co3O4 and untreated pristine CuO-Co3O4. These findings reveal the possibility of a new gateway for the capitalization of a chemically reduced sample into diverse energy storage and conversion systems such as lithium-ion batteries and supercapacitors.

  • 19.
    Aftab, Umair
    et al.
    Mehran Univ Engn and Technol, Pakistan.
    Tahira, Aneela
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, Faculty of Science & Engineering.
    Mazzaro, Raffaello
    Italian Natl Res Council, Italy.
    Morandi, Vittorio
    Italian Natl Res Council, Italy.
    Abro, Muhammad Ishaq
    Mehran Univ Engn and Technol, Pakistan.
    Baloch, Muhammad Moazam
    Mehran Univ Engn and Technol, Pakistan.
    Yu, Cong
    Chinese Acad Sci, Peoples R China.
    Ibupoto, Zafar Hussain
    Univ Sindh, Pakistan.
    Nickel-cobalt bimetallic sulfide NiCo(2)S(4)nanostructures for a robust hydrogen evolution reaction in acidic media2020In: RSC Advances, E-ISSN 2046-2069, RSC ADVANCES, Vol. 10, no 37, p. 22196-22203Article in journal (Refereed)
    Abstract [en]

    There are many challenges associated with the fabrication of efficient, inexpensive, durable and very stable nonprecious metal catalysts for the hydrogen evolution reaction (HER). In this study, we have designed a facile strategy by tailoring the concentration of precursors to successfully obtain nickel-cobalt bimetallic sulfide (NiCo2S4) using a simple hydrothermal method. The morphology of the newly prepared NiCo(2)S(4)comprised a mixture of microparticles and nanorods, which were few microns in dimension. The crystallinity of the composite sample was found to be excellent with a cubic phase. The sample that contained a higher amount of cobalt compared to nickel and produced single-phase NiCo(2)S(4)exhibited considerably improved HER performance. The variation in the salt precursor concentration during the synthesis of a material is a simple methodology to produce a scalable platinum-free catalyst for HER. The advantageous features of the multiple active sites of cobalt in the CN-21 sample as compared to that for pristine CoS and NiS laid the foundation for the provision of abundant active edges for HER. The composite sample produced a current density of 10 mA cm(-2)at an overpotential of 345 mV. Also, it exhibited a Tafel value of 60 mV dec(-1), which predominantly ensured rapid charge transfer kinetics during HER. CN-21 was highly durable and stable for 30 hours. Electrochemical impedance spectroscopy showed that the charge transfer resistance was 21.88 ohms, which further validated the HER polarization curves and Tafel results. CN-21 exhibited a double layer capacitance of 4.69 mu F cm(-2)and a significant electrochemically active surface area of 134.0 cm(2), which again supported the robust efficiency for HER. The obtained results reveal that our developed NiCo(2)S(4)catalyst has a high density of active edges, and it is a non-noble metal catalyst for the hydrogen evolution reaction. The present findings provide an alternative strategy and an active nonprecious material for the development of energy-related applications.

  • 20.
    Aftab, Umair
    et al.
    Mehran Univ Engn and Technol, Pakistan.
    Tahira, Aneela
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, Faculty of Science & Engineering.
    Samo, Abdul Hanan
    Mehran Univ Engn and Technol, Pakistan.
    Abro, Muhammad Ishaq
    Mehran Univ Engn and Technol, Pakistan.
    Baloch, Muhammad Moazam
    Mehran Univ Engn and Technol, Pakistan.
    Kumar, Mukesh
    Mehran Univ Engn and Technol, Pakistan.
    Sirajuddin,
    Univ Sindh Jamshoro, Pakistan.
    Ibupoto, Zafar Hussain
    Univ Sindh Jamshoro, Pakistan.
    Mixed CoS2@Co3O4 composite material: An efficient nonprecious electrocatalyst for hydrogen evolution reaction2020In: International journal of hydrogen energy, ISSN 0360-3199, E-ISSN 1879-3487, Vol. 45, no 27, p. 13805-13813Article in journal (Refereed)
    Abstract [en]

    Hydrogen evolution reaction (HER) has been identified as a sustainable and environment friendly technology for a wide range of energy conversion and storage applications. The big barrier in realizing this green technology requires a highly efficient, earth-abundant, and low-cost electrocatalyst for HER. Various HER catalysts have been designed and reported, still, their performance is not up to the mark of Pt. Among them, cobalt-based, especially cobalt disulfide (CoS2) has shown significant HER activity and found suitable candidature for HER due to its low cost, simple to prepare, and exhibits good stability. Herein, we synthesized various nanostructured materials including pure CoS2, Co3O4 and their composites by wet chemical methods and found them active for HER. The scanning electron microscopy (SEM) has revealed a morphology of composite as a mixture of nanowires and round shape spherical nanoparticles with several microns in dimension. The X-ray diffraction (XRD) confirmed the cubic phase of CoS2 and cubic phase of Co3O4 in the composite materials. The chemical deposition of CoS2 onto Co3O4 has tailored the HER activity of CoS2@Co3O4 composite material. Two CoS2@Co3O4 composite materials were produced with varying amounts of Co3O4 and labeled as samples 1 and 2. The Co3O4 reduced the adsorption energy for hydrogen, decreased the aggregation of CoS2 and uplifted the stability of CoS2@Co3O4 a composite material in alkaline media. Sample 1 requires an overpotential of 320 mV to reach a current density of 10 mA/cm(2) and it exhibits a Tafel slope of 42 mVdec(-1) which is the key indicator for the fast HER kinetics on sample 1. The sample 1 is highly durable for 50 h and also it has excellent stability. The electrochemical impedance spectroscopy (EIS) revealed a small charge transfer resistance of 28.81 Ohms for the sample 1 with high capacitance double-layer value of 0.81 mF. EIS has supported polarization and Tafel slope results. Based on the partial physical characterization and the electrochemical results, the as-obtained sample 1 (CoS2@Co3O4 composite material) will find potential applications in an extended range of energy conversion and storage devices owing to its low cost, high abundance, and excellent efficiency. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

  • 21.
    Afzali, Maryam
    et al.
    Cardiff Univ, Wales.
    Pieciak, Tomasz
    AGH Univ Sci & Technol, Poland; Univ Valladolid, Spain.
    Newman, Sharlene
    Indiana Univ, IN 47405 USA; Indiana Univ, IN 47405 USA.
    Garyfallidis, Eleftherios
    Indiana Univ, IN 47405 USA; Indiana Univ, IN 47408 USA.
    Özarslan, Evren
    Linköping University, Department of Biomedical Engineering, Division of Biomedical Engineering. Linköping University, Faculty of Science & Engineering. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Cheng, Hu
    Indiana Univ, IN 47405 USA; Indiana Univ, IN 47405 USA.
    Jones, Derek K.
    Cardiff Univ, Wales.
    The sensitivity of diffusion MRI to microstructural properties and experimental factors2021In: Journal of Neuroscience Methods, ISSN 0165-0270, E-ISSN 1872-678X, Vol. 347, article id 108951Article, review/survey (Refereed)
    Abstract [en]

    Diffusion MRI is a non-invasive technique to study brain microstructure. Differences in the microstructural properties of tissue, including size and anisotropy, can be represented in the signal if the appropriate method of acquisition is used. However, to depict the underlying properties, special care must be taken when designing the acquisition protocol as any changes in the procedure might impact on quantitative measurements. This work reviews state-of-the-art methods for studying brain microstructure using diffusion MRI and their sensitivity to microstructural differences and various experimental factors. Microstructural properties of the tissue at a micrometer scale can be linked to the diffusion signal at a millimeter-scale using modeling. In this paper, we first give an introduction to diffusion MRI and different encoding schemes. Then, signal representation-based methods and multi-compartment models are explained briefly. The sensitivity of the diffusion MRI signal to the microstructural components and the effects of curvedness of axonal trajectories on the diffusion signal are reviewed. Factors that impact on the quality (accuracy and precision) of derived metrics are then reviewed, including the impact of random noise, and variations in the acquisition parameters (i.e., number of sampled signals, b-value and number of acquisition shells). Finally, yet importantly, typical approaches to deal with experimental factors are depicted, including unbiased measures and harmonization. We conclude the review with some future directions and recommendations on this topic.

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  • 22.
    Ahlinder, Jon
    et al.
    Totalförsvarets Forskningsinstitut, FOI, Stockholm, Sweden.
    Nordgaard, Anders
    Swedish National Forensic Centre (NFC), Linköping, Sweden.
    Wiklund Lindström, Susanne
    Totalförsvarets Forskningsinstitut, FOI, Stockholm, Sweden.
    Chemometrics comes to court: evidence evaluation of chem–bio threat agent attacks2015In: Journal of Chemometrics, ISSN 0886-9383, E-ISSN 1099-128X, Vol. 29, no 5, p. 267-276Article in journal (Refereed)
    Abstract [en]

    Forensic statistics is a well-established scientific field whose purpose is to statistically analyze evidence in order to support legal decisions. It traditionally relies on methods that assume small numbers of independent variables and multiple samples. Unfortunately, such methods are less applicable when dealing with highly correlated multivariate data sets such as those generated by emerging high throughput analytical technologies. Chemometrics is a field that has a wealth of methods for the analysis of such complex data sets, so it would be desirable to combine the two fields in order to identify best practices for forensic statistics in the future. This paper provides a brief introduction to forensic statistics and describes how chemometrics could be integrated with its established methods to improve the evaluation of evidence in court.

    The paper describes how statistics and chemometrics can be integrated, by analyzing a previous know forensic data set composed of bacterial communities from fingerprints. The presented strategy can be applied in cases where chemical and biological threat agents have been illegally disposed.

  • 23. Order onlineBuy this publication >>
    Ahlner, Alexandra
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, The Institute of Technology.
    Improved Methods for Characterization of Protein Dynamics by NMR spectroscopy and Studies of the EphB2 Kinase Domain2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Proteins are essential for all known forms of life and in many lethal diseases protein failure is the cause of the disease. To understand proteins and the processes they are involved in, it is valuable to know their structures as well as their dynamics and interactions. The structures may not be directly inspected because proteins are too small to be visible in a light microscope, which is why indirect methods such as nuclear magnetic resonance (NMR) spectroscopy have to be utilized. This method provides atomic information about the protein and, in contrast to other methods with similar resolution, the measurements are performed in solution resulting in more physiological conditions, enabling analysis of dynamics. Important dynamical processes are the ones on the millisecond timeframe, which may contribute to interactions of proteins and their catalysis of chemical reactions, both of significant value for the function of the proteins.

    To better understand proteins, not only do we need to study them, but also develop the methods we are using. This thesis presents four papers about improved NMR techniques as well as a fifth where the kinase domain of ephrinB receptor 2 (EphB2) has been studied regarding the importance of millisecond dynamics and interactions for the activation process. The first paper presents the software COMPASS, which combines statistics and the calculation power of a computer with the flexibility and experience of the user to facilitate and speed up the process of assigning NMR signals to the atoms in the protein. The computer program PINT has been developed for easier and faster evaluation of NMR experiments, such as those that evaluate protein dynamics. It is especially helpful for NMR signals that are difficult to distinguish, so called overlapped peaks, and the soft- ware also converts the detected signals to the indirectly measured physical quantities, such as relaxation rate constants, principal for dynamics. Next are two new versions of the Carr-Purcell-Maiboom-Gill (CPMG) dispersion pulse sequences, designed to measure millisecond dynamics in a way so that the signals are more separated than in standard experiments, to reduce problems with overlaps. To speed up the collection time of the data set, a subset is collected and the entire data set is then reconstructed, by multi-dimensional decomposition co-processing. Described in the thesis is also a way to produce suitably labeled proteins, to detect millisecond dynamics at Cα positions in proteins, using the CPMG dispersion relaxation experiment at lower protein concentrations. Lastly, the kinase domain of EphB2 is shown to be more dynamic on the millisecond time scale as well as more prone to interact with itself in the active form than in the inactive one. This is important for the receptor function of the protein, when and how it mediates signals.

    To conclude, this work has extended the possibilities to study protein dynamics by NMR spectroscopy and contributed to increased understanding of the activation process of EphB2 and its signaling mechanism. 

    List of papers
    1. Fast and Accurate Resonance Assignment of Small-to-Large Proteins by Combining Automated and Manual Approaches
    Open this publication in new window or tab >>Fast and Accurate Resonance Assignment of Small-to-Large Proteins by Combining Automated and Manual Approaches
    Show others...
    2015 (English)In: PloS Computational Biology, ISSN 1553-734X, E-ISSN 1553-7358, Vol. 11, no 1, p. e1004022-Article in journal (Refereed) Published
    Abstract [en]

    The process of resonance assignment is fundamental to most NMR studies of protein structure and dynamics. Unfortunately, the manual assignment of residues is tedious and time-consuming, and can represent a significant bottleneck for further characterization. Furthermore, while automated approaches have been developed, they are often limited in their accuracy, particularly for larger proteins. Here, we address this by introducing the software COMPASS, which, by combining automated resonance assignment with manual intervention, is able to achieve accuracy approaching that from manual assignments at greatly accelerated speeds. Moreover, by including the option to compensate for isotope shift effects in deuterated proteins, COMPASS is far more accurate for larger proteins than existing automated methods. COMPASS is an open-source project licensed under GNU General Public License and is available for download from http://www.liu.se/forskning/foass/tidigare-foass/patrik-lundstrom/software?l=en. Source code and binaries for Linux, Mac OS X and Microsoft Windows are available.

    Place, publisher, year, edition, pages
    Public Library of Science, 2015
    National Category
    Chemical Sciences
    Identifiers
    urn:nbn:se:liu:diva-115010 (URN)10.1371/journal.pcbi.1004022 (DOI)000349309400013 ()25569628 (PubMedID)
    Note

    Funding Agencies|Swedish Research Council [Dnr. 2012-5136]

    Available from: 2015-03-09 Created: 2015-03-06 Last updated: 2021-12-28
    2. PINT: a software for integration of peak volumes and extraction of relaxation rates
    Open this publication in new window or tab >>PINT: a software for integration of peak volumes and extraction of relaxation rates
    2013 (English)In: Journal of Biomolecular NMR, ISSN 0925-2738, E-ISSN 1573-5001, Vol. 56, no 3, p. 191-202Article in journal (Refereed) Published
    Abstract [en]

    We present the software Peak INTegration (PINT), designed to perform integration of peaks in NMR spectra. The program is very simple to run, yet powerful enough to handle complicated spectra. Peaks are integrated by fitting predefined line shapes to experimental data and the fitting can be customized to deal with, for instance, heavily overlapped peaks. The results can be inspected visually, which facilitates systematic optimization of the line shape fitting. Finally, integrated peak volumes can be used to extract parameters such as relaxation rates and information about low populated states. The utility of PINT is demonstrated by applications to the 59 residue SH3 domain of the yeast protein Abp1p and the 289 residue kinase domain of murine EphB2.

    Place, publisher, year, edition, pages
    Springer Verlag (Germany), 2013
    Keywords
    Peak integration, Overlapped peaks, Relaxation rates, Protein dynamics
    National Category
    Cell and Molecular Biology
    Identifiers
    urn:nbn:se:liu:diva-95951 (URN)10.1007/s10858-013-9737-7 (DOI)000321544600001 ()
    Note

    Funding Agencies|Swedish Research Council||

    Available from: 2013-08-19 Created: 2013-08-12 Last updated: 2021-12-28Bibliographically approved
    3. Measurement of Protein Backbone 13CO and 15N Relaxation Dispersion at High Resolution
    Open this publication in new window or tab >>Measurement of Protein Backbone 13CO and 15N Relaxation Dispersion at High Resolution
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    Three-dimensional pulse sequences for the measurement of Carr-Purcell-Meiboom-Gill relaxation dispersions and new methods for co-processing non-uniformly sampled data are presented. The new methodology was validated for the disordered protein IgA and for an SH3 domain from Abp1p in exchange between its free form and bound to a peptide from the protein Ark1p. We show that the results are similar to ones obtained using traditional experiments and that accurate excited state chemical shifts can be determined. Furthermore, we show that jackknife analysis of down sampled spectra yields robust estimates of peak intensities errors, eliminating the need for recording duplicate data points. The methodology should be useful for characterization of millisecond dynamics in small to medium-sized proteins with poorly dispersed spectra.

    National Category
    Chemical Sciences
    Identifiers
    urn:nbn:se:liu:diva-117070 (URN)
    Available from: 2015-04-15 Created: 2015-04-15 Last updated: 2021-12-28Bibliographically approved
    4. Fractional enrichment of proteins using [2-13C]-glycerol as the carbon source facilitates measurement of excited state 13Cα chemical shifts with improved sensitivity
    Open this publication in new window or tab >>Fractional enrichment of proteins using [2-13C]-glycerol as the carbon source facilitates measurement of excited state 13Cα chemical shifts with improved sensitivity
    Show others...
    2015 (English)In: Journal of Biomolecular NMR, ISSN 0925-2738, E-ISSN 1573-5001, Vol. 62, no 3, p. 341-351Article in journal (Refereed) Published
    Abstract [en]

    A selective isotope labeling scheme based on the utilization of [2-13C]-glycerol as the carbon source during protein overexpression has been evaluated for the measurement of excited state 13Cα chemical shifts using Carr–Purcell–Meiboom–Gill (CPMG) relaxation dispersion (RD) experiments. As expected, the fractional incorporation of label at the Cα positions is increased two-fold relative to labeling schemes based on [2-13C]-glucose, effectively doubling the sensitivity of NMR experiments. Applications to a binding reaction involving an SH3 domain from the protein Abp1p and a peptide from the protein Ark1p establish that accurate excited state 13Cα chemical shifts can be obtained from RD experiments, with errors on the order of 0.06 ppm for exchange rates ranging from 100 to 1000 s−1, despite the small fraction of 13Cα–13Cβ spin-pairs that are present for many residue types. The labeling approach described here should thus be attractive for studies of exchanging systems using 13Cα spin probes.

    Place, publisher, year, edition, pages
    Springer Netherlands, 2015
    Keywords
    CPMG, 13Cα labeling, [2-13C]-Glycerol, Excited states
    National Category
    Chemical Sciences
    Identifiers
    urn:nbn:se:liu:diva-117073 (URN)10.1007/s10858-015-9948-1 (DOI)000357489200010 ()
    Note

    At the time for thesis presentation publication was in status: Manuscript

    At the time for thesis presentation name of publication was: Fractional enrichment using [2-13C]-glycerol as the carbon source facilitates measurements of excited state 13Cα chemical shifts with improved sensitivity

    Available from: 2015-04-15 Created: 2015-04-15 Last updated: 2021-12-28Bibliographically approved
    5. Conformational Dynamics and Multimerization of Active Forms of the EphrinB Receptor 2 Kinase Domain
    Open this publication in new window or tab >>Conformational Dynamics and Multimerization of Active Forms of the EphrinB Receptor 2 Kinase Domain
    Show others...
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    Active and autoinhibited forms of the ephrinB receptor 2 (EphB2) kinase domain have been studied using NMR spectroscopy. The project was initiated because of the finding that the crystal structures of active forms of the kinase domain and previous NMR studies suggested that a change in inter-lobe flexibility and the sampling of catalytically competent excited states conformations are responsible for activity. Using Carr-Purcell-Meiboom-Gill relaxation dispersion experiments, we have measured millisecond dynamics to identify such states. We have also performed concentration dependent relaxation experiments and analytical ultracentrifugation experiments that report on the effective protein size to look for possible differences in self-association for active and autoinhibited forms of the EphB2 kinase domain. We show that the active but not autoinhibited forms exchange between a ground state and an excited state at a rate of 1900 s-1. Similar results were found for the S677/680A mutant of the protein. The nature and importance of the excited state is still unknown. Our most important finding is that active forms of the kinase domain self-associate in a concentration dependent manner and form tetramers and possibly larger oligomers. Multimerization of the kinase domain may enable the assembly of complexes of downstream proteins and could be important for Eph signaling.

    Keywords
    Kinase activation | Eph receptors | chemical exchange | nmr spectroscopy | protein dynamics | self-association
    National Category
    Chemical Sciences
    Identifiers
    urn:nbn:se:liu:diva-117071 (URN)
    Available from: 2015-04-15 Created: 2015-04-15 Last updated: 2021-12-28Bibliographically approved
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  • 24.
    Ahlner, Alexandra
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, The Institute of Technology.
    Andresen, Cecilia
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, The Institute of Technology.
    Khan, Shahid N.
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, The Institute of Technology.
    Kay, Lewis E.
    Departments of Medical Genetics, Biochemistry and Chemistry, The University of Toronto, Canada.
    Lundström, Patrik
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, The Institute of Technology.
    Fractional enrichment of proteins using [2-13C]-glycerol as the carbon source facilitates measurement of excited state 13Cα chemical shifts with improved sensitivity2015In: Journal of Biomolecular NMR, ISSN 0925-2738, E-ISSN 1573-5001, Vol. 62, no 3, p. 341-351Article in journal (Refereed)
    Abstract [en]

    A selective isotope labeling scheme based on the utilization of [2-13C]-glycerol as the carbon source during protein overexpression has been evaluated for the measurement of excited state 13Cα chemical shifts using Carr–Purcell–Meiboom–Gill (CPMG) relaxation dispersion (RD) experiments. As expected, the fractional incorporation of label at the Cα positions is increased two-fold relative to labeling schemes based on [2-13C]-glucose, effectively doubling the sensitivity of NMR experiments. Applications to a binding reaction involving an SH3 domain from the protein Abp1p and a peptide from the protein Ark1p establish that accurate excited state 13Cα chemical shifts can be obtained from RD experiments, with errors on the order of 0.06 ppm for exchange rates ranging from 100 to 1000 s−1, despite the small fraction of 13Cα–13Cβ spin-pairs that are present for many residue types. The labeling approach described here should thus be attractive for studies of exchanging systems using 13Cα spin probes.

    Download full text (pdf)
    fulltext
  • 25.
    Ahlner, Alexandra
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, The Institute of Technology.
    Khan, Shahid N.
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, The Institute of Technology.
    Forman-Kay, Julie D.
    Molecular Structure and Function Program, Hospital for Sick Children; Department and Biochemistry, University of Toronto, Canada.
    Sicheri, Frank
    cDepartment and Biochemistry, University of Toronto; Department of Molecular Genetics, University of Toronto; Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Canada.
    Lundström, Patrik
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, The Institute of Technology.
    Conformational Dynamics and Multimerization of Active Forms of the EphrinB Receptor 2 Kinase DomainManuscript (preprint) (Other academic)
    Abstract [en]

    Active and autoinhibited forms of the ephrinB receptor 2 (EphB2) kinase domain have been studied using NMR spectroscopy. The project was initiated because of the finding that the crystal structures of active forms of the kinase domain and previous NMR studies suggested that a change in inter-lobe flexibility and the sampling of catalytically competent excited states conformations are responsible for activity. Using Carr-Purcell-Meiboom-Gill relaxation dispersion experiments, we have measured millisecond dynamics to identify such states. We have also performed concentration dependent relaxation experiments and analytical ultracentrifugation experiments that report on the effective protein size to look for possible differences in self-association for active and autoinhibited forms of the EphB2 kinase domain. We show that the active but not autoinhibited forms exchange between a ground state and an excited state at a rate of 1900 s-1. Similar results were found for the S677/680A mutant of the protein. The nature and importance of the excited state is still unknown. Our most important finding is that active forms of the kinase domain self-associate in a concentration dependent manner and form tetramers and possibly larger oligomers. Multimerization of the kinase domain may enable the assembly of complexes of downstream proteins and could be important for Eph signaling.

  • 26.
    Ahlner, Alexandra
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, The Institute of Technology.
    Mayzel, Maxim
    The Swedish NMR Centre, University of Gothenburg, Sweden.
    Lundström, Patrik
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, The Institute of Technology.
    Orekhov, Vladislav Y.
    The Swedish NMR Centre, University of Gothenburg, Sweden.
    Measurement of Protein Backbone 13CO and 15N Relaxation Dispersion at High ResolutionManuscript (preprint) (Other academic)
    Abstract [en]

    Three-dimensional pulse sequences for the measurement of Carr-Purcell-Meiboom-Gill relaxation dispersions and new methods for co-processing non-uniformly sampled data are presented. The new methodology was validated for the disordered protein IgA and for an SH3 domain from Abp1p in exchange between its free form and bound to a peptide from the protein Ark1p. We show that the results are similar to ones obtained using traditional experiments and that accurate excited state chemical shifts can be determined. Furthermore, we show that jackknife analysis of down sampled spectra yields robust estimates of peak intensities errors, eliminating the need for recording duplicate data points. The methodology should be useful for characterization of millisecond dynamics in small to medium-sized proteins with poorly dispersed spectra.

  • 27.
    Ahmadkhaniha, D.
    et al.
    Jonkoping Univ, Sweden.
    Eriksson, Fredrik
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Leisner, P.
    Jonkoping Univ, Sweden; RISE Res Inst Sweden, Sweden.
    Zanella, C.
    Jonkoping Univ, Sweden.
    Effect of SiC particle size and heat-treatment on microhardness and corrosion resistance of NiP electrodeposited coatings2018In: Journal of Alloys and Compounds, ISSN 0925-8388, E-ISSN 1873-4669, Vol. 769, p. 1080-1087Article in journal (Refereed)
    Abstract [en]

    Electrodeposition of NiP composite coatings with nano and sub-micron sized SiC has been carried out to investigate the possibility of replacing hard chromium coatings. The composition and structure of the coatings were evaluated by energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD) analysis, respectively. Microhardness was measured by Vickers indentation and polarization measurements were carried out to study the corrosion behavior of the coatings. The results showed that submicron particles can be codeposited with a higher content as compared to nano sized ones. However, even if a smaller amount of the nano-sized SiC particles are incorporated in the coating, the contribution to an increasing microhardness was comparable with the submicron sized particles, which can be related to the higher density of codeposited particles. SiC particles did not change the anodic polarization behavior of NiP coatings in a 3.5% NaCl solution. Finally, the effect of heat-treatment on the coatings properties at 400 degrees C for 1 h was studied to investigate the contribution of particles and heat-treatment on hardness and corrosion properties. It was found that the heat-treatment doubled the microhardness and changed the anodic polarization behavior of the coatings from passive to active with respect to the asplated conditions. (C) 2018 Elsevier B.V. All rights reserved.

  • 28.
    Ahmed, Bilal
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Materials design. Linköping University, Faculty of Science & Engineering.
    El Ghazaly, Ahmed
    Linköping University, Department of Physics, Chemistry and Biology, Materials design. Linköping University, Faculty of Science & Engineering.
    Halim, Joseph
    Linköping University, Department of Physics, Chemistry and Biology, Materials design. Linköping University, Faculty of Science & Engineering.
    Rosén, Johanna
    Linköping University, Department of Physics, Chemistry and Biology, Materials design. Linköping University, Faculty of Science & Engineering.
    Electrochemical activation of commercial graphite sheets for supercapacitive applications2022In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 431, article id 140882Article in journal (Refereed)
    Abstract [en]

    Carbon-based substrates are widely used as current collectors for high-performance energy storage materials in supercapacitors. However, these substrates exhibit negligible charge storage due to inferior electrochemical activity and small surface area. Herein, electrochemical activation is utilized to enhance the electrochemical activity of - inherently inactive - commercial graphite sheets for supercapacitive applications. The results reveal that the electrochemically activated graphite sheets render a 30-fold increase in areal capacitance, i.e., from 22 to 447 mF cm(-2), which can be ascribed to the activation of graphite oxide functional groups on the surface. Also, the influence of electrochemical activation time on electrochemical performance is explored in detail, followed by the fabrication and characterization of symmetric supercapacitors based on the optimum process parameters in single-cell and tandem configurations, demonstrating the potential of electrochemically activated graphite sheets in practical applications.

  • 29.
    Ahmed, Heba
    et al.
    RMIT Univ, Australia.
    Alijani, Hossein
    RMIT Univ, Australia.
    El Ghazaly, Ahmed
    Linköping University, Department of Physics, Chemistry and Biology, Materials design. Linköping University, Faculty of Science & Engineering.
    Halim, Joseph
    Linköping University, Department of Physics, Chemistry and Biology, Materials design. Linköping University, Faculty of Science & Engineering.
    Murdoch, Billy J.
    RMIT Univ, Australia.
    Ehrnst, Yemima
    RMIT Univ, Australia.
    Massahud, Emily
    RMIT Univ, Australia.
    Rezk, Amgad R.
    RMIT Univ, Australia.
    Rosén, Johanna
    Linköping University, Department of Physics, Chemistry and Biology, Materials design. Linköping University, Faculty of Science & Engineering.
    Yeo, Leslie Y.
    RMIT Univ, Australia.
    Recovery of oxidized two-dimensional MXenes through high frequency nanoscale electromechanical vibration2023In: Nature Communications, E-ISSN 2041-1723, Vol. 14, no 1, article id 3Article in journal (Refereed)
    Abstract [en]

    MXenes hold immense potential given their superior electrical properties. The practical adoption of these promising materials is, however, severely constrained by their oxidative susceptibility, leading to significant performance deterioration and lifespan limitations. Attempts to preserve MXenes have been limited, and it has not been possible thus far to reverse the materials performance. In this work, we show that subjecting oxidized micron or nanometer thickness dry MXene films-even those constructed from nanometer-order solution-dispersed oxidized flakes-to just one minute of 10 MHz nanoscale electromechanical vibration leads to considerable removal of its surface oxide layer, whilst preserving its structure and characteristics. Importantly, electrochemical performance is recovered close to that of their original state: the pseudocapacitance, which decreased by almost 50% due to its oxidation, reverses to approximately 98% of its original value, with good capacitance retention ( approximate to 93%) following 10,000 charge-discharge cycles at 10 A g(-1). These promising results allude to the exciting possibility for rejuvenating the material for reuse, therefore offering a more economical and sustainable route that improves its potential for practical translation. Despite their vast potential, the practical deployment of MXenes has been hampered by their tendency to be oxidized. Here, the authors show that simply vibrating MXene films in just a minute can remove the oxide layer formed and restore their electrochemical performance close to its original state.

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    fulltext
  • 30.
    Ahmed, Heba
    et al.
    RMIT Univ, Australia.
    Yang, Xinci
    RMIT Univ, Australia.
    Ehrnst, Yemima
    RMIT Univ, Australia.
    Jeorje, Ninweh N.
    RMIT Univ, Australia.
    Marqus, Susan
    RMIT Univ, Australia.
    Sherrell, Peter C.
    RMIT Univ, Australia; Univ Melbourne, Australia.
    El Ghazaly, Ahmed
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Rosén, Johanna
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Rezk, Amgad R.
    RMIT Univ, Australia.
    Yeo, Leslie Y.
    RMIT Univ, Australia.
    Ultrafast assembly of swordlike Cu-3(1,3,5-benzenetricarboxylate)(n) metal-organic framework crystals with exposed active metal sites2020In: Nanoscale Horizons, ISSN 2055-6764, E-ISSN 2055-6756, Vol. 5, no 7, p. 1050-1057Article in journal (Refereed)
    Abstract [en]

    Owing to their large surface area and high uptake capacity, metal-organic frameworks (MOFs) have attracted considerable attention as potential materials for gas storage, energy conversion, and electrocatalysis. Various strategies have recently been proposed to manipulate the MOF surface chemistry to facilitate exposure of the embedded metal centers at the crystal surface to allow more effective binding of target molecules to these active sites. Nevertheless, such strategies remain complex, often requiring strict control over the synthesis conditions to avoid blocking pore access, reduction in crystal quality, or even collapse of the entire crystal structure. In this work, we exploit the hydrodynamics and capillary resonance associated with acoustically-driven dynamically spreading and nebulizing thin films as a new method for ultrafast synthesis of swordlike Cu-3(1,3,5-benzenetricarboxylate)(n) (Cu-BTC) MOFs with unique monoclinic crystal structures (P2(1)/n) distinct to that obtained via conventional bulk solvothermal synthesis, with swordlike morphologies whose lengths far exceed their thicknesses. Through pulse modulation and taking advantage of the rapid solvent evaporation associated with the high nebulisation rates, we are also able to control the thicknesses of these large aspect ratio (width and length with respect to the thickness) crystals by arresting their vertical growth, which, in turn, allows exposure of the metal active sites at the crystal surface. An upshot of such active site exposure on the crystal surface is the concomitant enhancement in the conductivity of the MOF, evident from the improvement in its current density by two orders of magnitude.

  • 31.
    Ahmed Khand, Aftab
    et al.
    Tsinghua Univ Beijing, Peoples R China; Univ Sindh Jamshoro, Pakistan.
    Ahmed Lakho, Saeed
    Univ Karachi, Pakistan.
    Tahira, Aneela
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, Faculty of Science & Engineering.
    Ahmed, Mansoor
    Univ Karachi, Pakistan.
    Aftab, Umair
    MUET, Pakistan.
    Abro, Muhammad Ishaq
    MUET, Pakistan.
    Juno, Awais Ahmed
    Ziauddin Univ, Pakistan.
    Nafady, Ayman
    King Saud Univ, Saudi Arabia.
    Ibupoto, Zafar Hussain
    Univ Sindh Jamshoro, Pakistan.
    Synthesis of Sheet Like Nanostructures of NiO Using Potassium Dichromate as Surface Modifying Agent for the Sensitive and Selective Determination of Amlodipine Besylate (ADB) Drug2021In: Electroanalysis, ISSN 1040-0397, E-ISSN 1521-4109, Vol. 33, no 5, p. 1121-1128Article in journal (Refereed)
    Abstract [en]

    The monitoring of hypertension drugs is very critical and important to sustain a healthy life. In this study, we have synthesized nickel oxide (NiO) nanostructures using potassium dichromate as surface modifying agent by hydrothermal method. These NiO nanostructures were found highly active for the oxidation of ADB besylate (ADB). The unit cell structure and morphology were investigated by scanning electron microscopy (SEM) and powder X-ray diffraction (XRD) techniques. The SEM study has confirmed the nano sheet like morphology and XRD analysis has described the cubic unit arrays of NiO. After the physical characterization, NiO nanostructures were used to modify the surface of glassy carbon electrode (GCE) by drop casting method. Then cyclic voltammetry (CV) was used to characterize the electrochemical activity of NiO nanostructures in the0.1 M phosphate buffer solution of pH 10.0 and a well resolved oxidation peak was identified at 0.70 V. The linear range for the NiO nanostructures was observed from 20-90 nM with a regression coefficient of 0.99 using CV. The calculated limit of detection (LOD) was 2.125 nM and the limit of quantification (LOQ) was 4.08 nM. Further to validate the CV calibration plot, an amperometry experiment was performed on the NiO nanostructures and sensors exhibited a linear range of 10 nM to 115 nM with LOD of 1.15 nM. The proposed approach was successfully used for the determination of ADB from commercial tablets and it reveals that the sensor could be capitalized to monitor ADB concentrations from pharmaceutical products. The use of potassium dichromate as a surface modifying agent for the metal oxide nanostructures may be of great interest to manipulate their crystal and surface properties for the extended range of biomedical and energy related applications.

  • 32.
    Ahsan, Aisha
    et al.
    Univ Basel, Switzerland.
    Mousavi, S. Fatemeh
    Univ Basel, Switzerland.
    Nijs, Thomas
    Univ Basel, Switzerland.
    Nowakowska, Sylwia
    Univ Basel, Switzerland.
    Popova, Olha
    Univ Basel, Switzerland.
    Wackerlin, Aneliia
    Univ Basel, Switzerland.
    Björk, Jonas
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Gade, Lutz H.
    Heidelberg Univ, Germany.
    Jung, Thomas A.
    Univ Basel, Switzerland; Paul Scherrer Inst, Switzerland.
    Watching nanostructure growth: kinetically controlled diffusion and condensation of Xe in a surface metal organic network2019In: Nanoscale, ISSN 2040-3364, E-ISSN 2040-3372, Vol. 11, no 11, p. 4895-4903Article in journal (Refereed)
    Abstract [en]

    Diffusion, nucleation and growth provide the fundamental access to control nanostructure growth. In this study, the temperature activated diffusion of Xe at and between different compartments of an on-surface metal organic coordination network on Cu(111) has been visualized in real space. Xe atoms adsorbed at lower energy sites become mobile with increased temperature and gradually populate energetically more favourable binding sites or remain in a delocalized fluid form confined to diffusion along a topological subset of the on-surface network. These diffusion pathways can be studied individually under kinetic control via the chosen thermal energy kT of the sample and are determined by the network and sample architecture. The spatial distribution of Xe in its different modes of mobility and the time scales of the motion is revealed by Scanning Tunneling Microscopy (STM) at variable temperatures up to 40 K and subsequent cooling to 4 K. The system provides insight into the diffusion of a van der Waals gas on a complex structured surface and its nucleation and coarsening/growth into larger condensates at elevated temperature under thermodynamic conditions.

  • 33.
    Ahvenniemi, Esko
    et al.
    Aalto University, Finland.
    Akbashev, Andrew R.
    Stanford University, CA 94305 USA.
    Ali, Saima
    Aalto University, Finland.
    Bechelany, Mikhael
    University of Montpellier, France.
    Berdova, Maria
    University of Twente, Netherlands.
    Boyadjiev, Stefan
    Bulgarian Academic Science, Bulgaria.
    Cameron, David C.
    Masaryk University, Czech Republic.
    Chen, Rong
    Huazhong University of Science and Technology, Peoples R China.
    Chubarov, Mikhail
    University of Grenoble Alpes, France.
    Cremers, Veronique
    University of Ghent, Belgium.
    Devi, Anjana
    Ruhr University of Bochum, Germany.
    Drozd, Viktor
    St Petersburg State University, Russia.
    Elnikova, Liliya
    Institute Theoret and Expt Phys, Russia.
    Gottardi, Gloria
    Fdn Bruno Kessler, Italy.
    Grigoras, Kestutis
    VTT Technical Research Centre Finland, Finland.
    Hausmann, Dennis M.
    Lam Research Corp, OR 97062 USA.
    Seong Hwang, Cheol
    Seoul National University, South Korea; Seoul National University, South Korea.
    Jen, Shih-Hui
    Globalfoundries, NY 12203 USA.
    Kallio, Tanja
    Aalto University, Finland.
    Kanervo, Jaana
    Aalto University, Finland; Abo Akad University, Finland.
    Khmelnitskiy, Ivan
    St Petersburg Electrotech University of LETI, Russia.
    Han Kim, Do
    MIT, MA 02139 USA.
    Klibanov, Lev
    Techinsights, Canada.
    Koshtyal, Yury
    Ioffe Institute, Russia.
    Krause, A. Outi I.
    Aalto University, Finland.
    Kuhs, Jakob
    University of Ghent, Belgium.
    Kaerkkaenen, Irina
    Sentech Instruments GmbH, Germany.
    Kaariainen, Marja-Leena
    NovaldMedical Ltd Oy, Finland.
    Kaariainen, Tommi
    NovaldMedical Ltd Oy, Finland; University of Helsinki, Finland.
    Lamagna, Luca
    STMicroelectronics, Italy.
    Lapicki, Adam A.
    Seagate Technology Ireland, North Ireland.
    Leskela, Markku
    University of Helsinki, Finland.
    Lipsanen, Harri
    Aalto University, Finland.
    Lyytinen, Jussi
    Aalto University, Finland.
    Malkov, Anatoly
    Technical University, Russia.
    Malygin, Anatoly
    Technical University, Russia.
    Mennad, Abdelkader
    CDER, Algeria.
    Militzer, Christian
    Technical University of Chemnitz, Germany.
    Molarius, Jyrki
    Summa Semicond Oy, Finland.
    Norek, Malgorzata
    Mil University of Technology, Poland.
    Ozgit-Akgun, Cagla
    ASELSAN Inc, Turkey.
    Panov, Mikhail
    St Petersburg Electrotech University of LETI, Russia.
    Pedersen, Henrik
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    Piallat, Fabien
    KOBUS, France.
    Popov, Georgi
    University of Helsinki, Finland.
    Puurunen, Riikka L.
    VTT Technical Research Centre Finland, Finland.
    Rampelberg, Geert
    University of Ghent, Belgium.
    Ras, Robin H. A.
    Aalto University, Espoo, Finland.
    Rauwel, Erwan
    Tallinn University of Technology, Estonia.
    Roozeboom, Fred
    Eindhoven University of Technology, Netherlands; TNO, Netherlands.
    Sajavaara, Timo
    University of Jyvaskyla, Finland.
    Salami, Hossein
    University of Maryland, MD 20742 USA.
    Savin, Hele
    Aalto University, Finland.
    Schneider, Nathanaelle
    IRDEP CNRS, France; IPVF, France.
    Seidel, Thomas E.
    Seitek50, FL 32135 USA.
    Sundqvist, Jonas
    Fraunhofer Institute Ceram Technology and Syst IKTS, Germany.
    Suyatin, Dmitry B.
    Lund University, Sweden; Lund University, Sweden.
    Torndahl, Tobias
    Uppsala University, Sweden.
    van Ommen, J. Ruud
    Delft University of Technology, Netherlands.
    Wiemer, Claudia
    CNR, Italy.
    Ylivaara, Oili M. E.
    VTT Technical Research Centre Finland, Finland.
    Yurkevich, Oksana
    Immanuel Kant Balt Federal University, Russia.
    Recommended reading list of early publications on atomic layer deposition-Outcome of the "Virtual Project on the History of ALD"2017In: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 35, no 1, article id 010801Article, review/survey (Refereed)
    Abstract [en]

    Atomic layer deposition (ALD), a gas-phase thin film deposition technique based on repeated, self-terminating gas-solid reactions, has become the method of choice in semiconductor manufacturing and many other technological areas for depositing thin conformal inorganic material layers for various applications. ALD has been discovered and developed independently, at least twice, under different names: atomic layer epitaxy (ALE) and molecular layering. ALE, dating back to 1974 in Finland, has been commonly known as the origin of ALD, while work done since the 1960s in the Soviet Union under the name "molecular layering" (and sometimes other names) has remained much less known. The virtual project on the history of ALD (VPHA) is a volunteer-based effort with open participation, set up to make the early days of ALD more transparent. In VPHA, started in July 2013, the target is to list, read and comment on all early ALD academic and patent literature up to 1986. VPHA has resulted in two essays and several presentations at international conferences. This paper, based on a poster presentation at the 16th International Conference on Atomic Layer Deposition in Dublin, Ireland, 2016, presents a recommended reading list of early ALD publications, created collectively by the VPHA participants through voting. The list contains 22 publications from Finland, Japan, Soviet Union, United Kingdom, and United States. Up to now, a balanced overview regarding the early history of ALD has been missing; the current list is an attempt to remedy this deficiency. (C) 2016 Author(s).

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  • 34.
    Aijaz, Asim
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Plasma and Coating Physics. Linköping University, The Institute of Technology. Uppsala University, Sweden.
    Louring, Sascha
    Aarhus University, Denmark; Danish Technology Institute, Denmark.
    Lundin, Daniel
    University of Paris Saclay, France.
    Kubart, Tomas
    Uppsala University, Sweden.
    Jensen, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Sarakinos, Kostas
    Linköping University, Department of Physics, Chemistry and Biology, Nanoscale engineering. Linköping University, Faculty of Science & Engineering.
    Helmersson, Ulf
    Linköping University, Department of Physics, Chemistry and Biology, Plasma and Coating Physics. Linköping University, Faculty of Science & Engineering.
    Synthesis of hydrogenated diamondlike carbon thin films using neon-acetylene based high power impulse magnetron sputtering discharges2016In: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 34, no 6, article id 061504Article in journal (Refereed)
    Abstract [en]

    Hydrogenated diamondlike carbon (DLC:H) thin films exhibit many interesting properties that can be tailored by controlling the composition and energy of the vapor fluxes used for their synthesis. This control can be facilitated by high electron density and/or high electron temperature plasmas that allow one to effectively tune the gas and surface chemistry during film growth, as well as the degree of ionization of the film forming species. The authors have recently demonstrated by adding Ne in an Ar-C high power impulse magnetron sputtering (HiPIMS) discharge that electron temperatures can be effectively increased to substantially ionize C species [Aijaz et al., Diamond Relat. Mater. 23, 1 (2012)]. The authors also developed an Ar-C2H2 HiPIMS process in which the high electron densities provided by the HiPIMS operation mode enhance gas phase dissociation reactions enabling control of the plasma and growth chemistry [Aijaz et al., Diamond Relat. Mater. 44, 117 (2014)]. Seeking to further enhance electron temperature and thereby promote electron impact induced interactions, control plasma chemical reaction pathways, and tune the resulting film properties, in this work, the authors synthesize DLC: H thin films by admixing Ne in a HiPIMS based Ar/C2H2 discharge. The authors investigate the plasma properties and discharge characteristics by measuring electron energy distributions as well as by studying discharge current characteristics showing an electron temperature enhancement in C2H2 based discharges and the role of ionic contribution to the film growth. These discharge conditions allow for the growth of thick (amp;gt;1 mu m) DLC: H thin films exhibiting low compressive stresses (similar to 0.5 GPa), high hardness (similar to 25 GPa), low H content (similar to 11%), and density in the order of 2.2 g/cm(3). The authors also show that film densification and change of mechanical properties are related to H removal by ion bombardment rather than subplantation. (C) 2016 American Vacuum Society.

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  • 35.
    Ail, Ujwala
    et al.
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Backe, Jakob
    Ligna Energy AB, Kallvindsgatan 5, S-60240 Norrkoping, Sweden.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Crispin, Xavier
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Phopase, Jaywant
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Lignin Functionalized with Catechol for Large-Scale Organic Electrodes in Bio-Based Batteries2023In: ADVANCED ENERGY AND SUSTAINABILITY RESEARCH, ISSN 2699-9412Article in journal (Refereed)
    Abstract [en]

    Lignin, obtained as a waste product in huge quantities from the large-scale cellulose processing industries, holds a great potential to be used as sustainable electrode material for large-scale electroactive energy storage systems. The fixed number of redox-active phenolic groups present within the lignin structure limits the electrochemical performance and the total energy storage capacity of the lignin-based electrodes. Herein, the way to enhance the charge storage capacity of lignin by incorporating additional small catechol molecules into the lignin structure is demonstrated. The catechol derivatives are covalently attached to the lignin via aromatic electrophilic substitution reaction. The increased phenolic groups in all functionalized lignin derivatives notably increase the values of capacitance compared to pristine lignin. Further, solvent fractionation of lignin followed by functionalization using catechol boosts three times the charge capacity of lignin electrode. Herein, a scalable, cost-effective method to enhance the electrochemical performance of lignin electrodes via incorporation of small redox active moieties into the lignin structure is demonstrated. Solvent fractionation of lignin followed by functionalization using catechol increases the charge storage capacity of the lignin-carbon composite electrode by a factor of 3 reaching record high charge capacity above 100 mAh g-1.

  • 36.
    Ail, Ujwala
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Jafari, Mohammad Javad
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Physics. Linköping University, Faculty of Science & Engineering.
    Wang, Hui
    Linköping University, Department of Science and Technology. Linköping University, Faculty of Science & Engineering.
    Ederth, Thomas
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Physics. Linköping University, Faculty of Science & Engineering.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Crispin, Xavier
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Thermoelectric Properties of Polymeric Mixed Conductors2016In: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 26, no 34, p. 6288-6296Article in journal (Refereed)
    Abstract [en]

    The thermoelectric (TE) phenomena are intensively explored by the scientific community due to the rather inefficient way energy resources are used with a large fraction of energy wasted in the form of heat. Among various materials, mixed ion-electron conductors (MIEC) are recently being explored as potential thermoelectrics, primarily due to their low thermal conductivity. The combination of electronic and ionic charge carriers in those inorganic or organic materials leads to complex evolution of the thermovoltage (Voc) with time, temperature, and/or humidity. One of the most promising organic thermoelectric materials, poly(3,4-ethyelenedioxythiophene)-polystyrene sulfonate (PEDOT-PSS), is an MIEC. A previous study reveals that at high humidity, PEDOT-PSS undergoes an ionic Seebeck effect due to mobile protons. Yet, this phenomenon is not well understood. In this work, the time dependence of the Voc is studied and its behavior from the contribution of both charge carriers (holes and protons) is explained. The presence of a complex reorganization of the charge carriers promoting an internal electrochemical reaction within the polymer film is identified. Interestingly, it is demonstrated that the time dependence behavior of Voc is a way to distinguish between three classes of polymeric materials: electronic conductor, ionic conductor, and mixed ionic–electronic conductor

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  • 37.
    Ail, Ujwala
    et al.
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Nilsson, Jakob
    Ligna Energy AB, Sweden.
    Jansson, Mattias
    Linköping University, Department of Physics, Chemistry and Biology, Electronic and photonic materials. Linköping University, Faculty of Science & Engineering.
    Buyanova, Irina A
    Linköping University, Department of Physics, Chemistry and Biology, Electronic and photonic materials. Linköping University, Faculty of Science & Engineering.
    Wu, Zhixing
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering.
    Björk, Emma
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Crispin, Xavier
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Optimization of Non-Pyrolyzed Lignin Electrodes for Sustainable Batteries2023In: ADVANCED SUSTAINABLE SYSTEMS, ISSN 2366-7486, Vol. 7, no 2, article id 2200396Article in journal (Refereed)
    Abstract [en]

    Lignin, a byproduct from the pulp industry, is one of the redox active biopolymers being investigated as a component in the electrodes for sustainable energy storage applications. Due to its insulating nature, it needs to be combined with a conductor such as carbon or conducting polymer for efficient charge storage. Here, the lignin/carbon composite electrodes manufactured via mechanical milling (ball milling) are reported. The composite formation, correlation between performance and morphology is studied by comparison with manual mixing and jet milling. Superior charge storage capacity with approximate to 70% of the total contribution from the Faradaic process involving the redox functionality of lignin is observed in a mechanically milled composite. In comparison, manual mix shows only approximate to 30% from the lignin storage participation while the rest is due to the electric double layer at the carbon-electrolyte interface. The significant participation of lignin in the ball milled composite is attributed to the homogeneous, intimate mixing of the carbon and the lignin leading the electronic carrier transported in the carbon phase to reach most of the redox group of lignin. A maximum capacity of 49 mAh g(-1) is obtained at charge/discharge rate of 0.25 A g(-1) for the sample milled for 60 min.

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  • 38.
    Ail, Ujwala
    et al.
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Phopase, Jaywant
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Nilsson, Jakob
    Ligna Energy AB, Sweden.
    Khan, Zia
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Electronic and photonic materials. Linköping University, Faculty of Science & Engineering.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Crispin, Xavier
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Effect of Sulfonation Level on Lignin/Carbon Composite Electrodes for Large-Scale Organic Batteries2020In: ACS Sustainable Chemistry and Engineering, E-ISSN 2168-0485, Vol. 8, no 49, p. 17933-17944Article in journal (Refereed)
    Abstract [en]

    The key figure-of-merit for materials in stationary energy storage applications, such as large-scale energy storage for buildings and grids, is the cost per kilo per electrochemical cycle, rather than the energy density. In this regard, forest-based biopolymers such as lignin, are attractive, as they are abundant on Earth. Here, we explored lignin as an electroactive battery material, able to store two electrons per hydroquinone aromatic ring, with the targeted operation in aqueous electrolytes. The impact of the sulfonation level of lignin on the performance of its composite electrode with carbon was investigated by considering three lignin derivatives: lignosulfonate (LS), partially desulfonated lignosulfonate (DSLS), and fully desulfonated lignin (KL, lignin produced by the kraft process). Partial desulfonation helped in better stability of the composite in aqueous media, simultaneously favoring its water processability. In this way, a route to promote ionic conductivity within the lignin/carbon composite electrodes was developed, facilitating the access to the entire bulk of the volumetric electrodes. Electrochemical performance of DSLS/C showed highly dominant Faradaic contribution (66%) towards the total capacity, indicating an efficient mixed ionic-electronic transport within the lignin-carbon phase, displaying a capacity of 38 mAh/g at 0.25 A/g and 69% of capacity retention after 2200 cycles at a rate of 1 A/g.

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  • 39.
    Ail, Ujwala
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Ullah Khan, Zia
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Granberg, Hjalmar
    Innventia AB, Sweden.
    Berthold, Fredrik
    Innventia AB, Sweden.
    Parasuraman, Rajasekar
    Mat Research Centre, India.
    Urnarji, Arun M.
    Mat Research Centre, India.
    Slettengren, Kerstin
    Innventia AB, Sweden.
    Pettersson, Henrik
    Innventia AB, Sweden.
    Crispin, Xavier
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Room temperature synthesis of transition metal silicide-conducting polymer micro-composites for thermoelectric applications2017In: Synthetic metals, ISSN 0379-6779, E-ISSN 1879-3290, Vol. 225, p. 55-63Article in journal (Refereed)
    Abstract [en]

    Organic polymer thermoelectrics (TE) as well as transition metal (TM) silicides are two thermoelectric class of materials of interest because they are composed of atomic elements of high abundatice; which is a prerequisite for mass implementation of thermoelectric (TE) solutions for solar and waste heat recovery. But both materials have drawbacks when it comes to finding low-cost manufacturing. The metal silicide needs high temperature (amp;gt;1000 degrees C) for creating TE legs in a device from solid powder, but it is easy to achieve long TE legs in this case. On the contrary, organic TEs are synthesized at low temperature from solution. However, it is difficult to form long legs or thick films because of their low solubility. In this work, we propose a novel method for the room temperature synthesis of TE composite containing the microparticles of chromium disilicide; CrSi2 (inorganic filler) in an organic matrix of nanofibrillated cellulose-poly(3,4-ethyelenedioxythiophene)-polystyrene sulfonate (NFC-PEDOT:PSS). With this method, it is easy to create long TE legs in a room temperature process. The originality of the approach is the use of conducting polymer aerogel microparticles mixed with CrSi2 microparticles to obtain a composite solid at room temperature under pressure. We foresee that the method can be scaled up to fabricate and pattern TE modules. The composite has an electrical conductivity (sigma) of 5.4 +/- 0.5 S/cm and the Seebeck coefficient (a) of 88 +/- 9 mu V/K, power factor (alpha(2)sigma) of 4 +/- 1 mu Wm(-1) K-2 at room temperature. At a temperature difference of 32 degrees C, the output power/unit area drawn across the load, with the resistance same as the internal resistance of the device is 0.6 +/- 0.1 mu W/cm(2). (C) 2017 Elsevier B.V. All rights reserved.

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  • 40.
    Aili, Daniel
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics . Linköping University, The Institute of Technology.
    Enander, Karin
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics . Linköping University, The Institute of Technology.
    Baltzer, Lars
    Division of Organic Chemistry, Department of Biochemistry and Organic Chemistry, BMC, Box 576, Uppsala UniVersity, SE-751 23 Uppsala, Sweden.
    Liedberg, Bo
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics . Linköping University, The Institute of Technology.
    Assembly of Polypeptide-Functionalized Gold Nanoparticles through a Heteroassociation- and Folding-Dependent Bridging2008In: Nano letters (Print), ISSN 1530-6984, E-ISSN 1530-6992, Vol. 8, no 8, p. 2473-2478Article in journal (Refereed)
    Abstract [en]

    Gold nanoparticles were functionalized with a synthetic polypeptide, de novo-designed to associate with a charge complementary linker polypeptide in a folding-dependent manner. A heterotrimeric complex that folds into two disulphide-linked four-helix bundles is formed when the linker polypeptide associates with two of the immobilized peptides. The heterotrimer forms in between separate particles and induces a rapid and extensive aggregation with a well-defined interparticle spacing. The aggregated particles are redispersed when the disulphide bridge in the linker polypeptide is reduced.

  • 41.
    Aili, Daniel
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Physics. Linköping University, Faculty of Science & Engineering.
    Selegård, Robert
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Physics. Linköping University, Faculty of Science & Engineering.
    Baltzer, Lars
    Division of Organic Chemistry, Department of Biochemistry and Organic Chemistry, BMC, Box 576, Uppsala University, SE-751 23 Uppsala, Sweden.
    Enander, Karin
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Physics. Linköping University, Faculty of Science & Engineering.
    Liedberg, Bo
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Physics. Linköping University, Faculty of Science & Engineering.
    Colorimetric Protein Sensing by Controlled Assembly of Gold Nanoparticles Functionalized with Synthetic Receptors2009In: Small, ISSN 1613-6810, Vol. 5, no 21, p. 2445-2452Article in journal (Refereed)
    Abstract [en]

    A strategy for colorimetric sensing of proteins, based on the induced assembly of polypeptide-functionalized gold nanoparticles, is described. Recognition was accomplished using a polypeptide sensor scaffold designed to specifically bind the model analyte, human carbonic anhydrase II (HCAII). The extent of particle aggregation, induced by the Zn2+-triggered dimerization and folding of a second polypeptide also present on the surface of the gold nanoparticle, gave a readily detectable colorimetric shift that was dependent on the concentration of the target protein. In the absence of HCAII, particle aggregation resulted in a major redshift of the plasmon peak whereas analyte binding prevented formation of dense aggregates, significantly reducing the magnitude of the redshift. The limit of detection of HCAII was estimated to be around 15 nM. The versatility of the technique was demonstrated using a second model system based on the recognition of a peptide sequence from the tobacco mosaic virus coat protein (TMVP by a recombinant antibody fragment. This strategy is proposed as a generic platform for robust and specific protein analysis that can be further developed for monitoring a wide range of target proteins.

  • 42.
    Ait-Mammar, Walid
    et al.
    Univ Paris Diderot, France.
    Zrig, Samia
    Univ Paris Diderot, France.
    Bridonneau, Nathalie
    Univ Paris Diderot, France.
    Noel, Vincent
    Univ Paris Diderot, France.
    Stavrinidou, Eleni
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Piro, Benoit
    Univ Paris Diderot, France.
    Mattana, Giorgio
    Univ Paris Diderot, France.
    All-Inkjet-Printed Humidity Sensors for the Detection of Relative Humidity in Air and Soil-Towards the Direct Fabrication on Plant Leaves2020In: MRS Advances, E-ISSN 2059-8521, Vol. 5, no 18-19, p. 965-973Article in journal (Refereed)
    Abstract [en]

    We demonstrate the fabrication, by exclusive means of inkjet-printing, of capacitive relative humidity sensors on flexible, plastic substrate. These sensors can be successfully used for the measurement of relative-humidity in both air and common soil. We also show that the same technique may be used for the fabrication of the same type of sensors on the surface of the leaves of El AE gnus Ebbingei (silverberry).Our results demonstrate the suitability of leaves as substrate for printed electronics and pave the way to the next generation of sensors to be used in fields such as agriculture and flower farming.

  • 43.
    Ajjan, Fátima
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Ambrogi, Martina
    Max Planck Institute Colloids and Interfaces, Germany.
    Ayalneh Tiruye, Girum
    IMDEA Energy Institute, Spain.
    Cordella, Daniela
    University of Liege ULg, Belgium.
    Fernandes, Ana M.
    POLYMAT University of Basque Country UPV EHU, Spain.
    Grygiel, Konrad
    Max Planck Institute Colloids and Interfaces, Germany.
    Isik, Mehmet
    POLYMAT University of Basque Country UPV EHU, Spain.
    Patil, Nagaraj
    University of Liege ULg, Belgium.
    Porcarelli, Luca
    POLYMAT University of Basque Country UPV EHU, Spain.
    Rocasalbas, Gillem
    KIOMedPharma, Belgium.
    Vendramientto, Giordano
    University of Bordeaux, France.
    Zeglio, Erica
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Antonietti, Markus
    Max Planck Institute Colloids and Interfaces, Germany.
    Detrembleur, Cristophe
    University of Liege ULg, Belgium.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Jerome, Christine
    University of Liege ULg, Belgium.
    Marcilla, Rebeca
    IMDEA Energy Institute, Spain.
    Mecerreyes, David
    POLYMAT University of Basque Country UPV EHU, Spain; Basque Fdn Science, Spain.
    Moreno, Monica
    POLYMAT University of Basque Country UPV EHU, Spain.
    Taton, Daniel
    University of Bordeaux, France.
    Solin, Niclas
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Yuan, Jiayin
    Max Planck Institute Colloids and Interfaces, Germany.
    Innovative polyelectrolytes/poly(ionic liquid)s for energy and the environment2017In: Polymer international, ISSN 0959-8103, E-ISSN 1097-0126, Vol. 66, no 8, p. 1119-1128Article, review/survey (Refereed)
    Abstract [en]

    This paper presents the work carried out within the European project RENAISSANCE-ITN, which was dedicated to the development of innovative polyelectrolytes for energy and environmental applications. Within the project different types of innovative polyelectrolytes were synthesized such as poly(ionic liquid)s coming from renewable or natural ions, thiazolium cations, catechol functionalities or from a new generation of cheap deep eutectic monomers. Further, macromolecular architectures such as new poly(ionic liquid) block copolymers and new (semi)conducting polymer/polyelectrolyte complexes were also developed. As the final goal, the application of these innovative polymers in energy and the environment was investigated. Important advances in energy storage technologies included the development of new carbonaceous materials, new lignin/conducting polymer biopolymer electrodes, new iongels and single-ion conducting polymer electrolytes for supercapacitors and batteries and new poly(ionic liquid) binders for batteries. On the other hand, the use of innovative polyelectrolytes in sustainable environmental technologies led to the development of new liquid and dry water, new materials for water cleaning technologies such as flocculants, oil absorbers, new recyclable organocatalyst platforms and new multifunctional polymer coatings with antifouling and antimicrobial properties. All in all this paper demonstrates the potential of poly(ionic liquid)s for high-value applications in energy and enviromental areas. (c) 2017 Society of Chemical Industry

  • 44.
    Ajjan, Fátima
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Javad Jafari, Mohammad
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Physics. Linköping University, Faculty of Science & Engineering.
    Rebis, T.
    Poznan University of Tech, Poland.
    Ederth, Thomas
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Physics. Linköping University, Faculty of Science & Engineering.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Spectroelectrochemical investigation of redox states in a polypyrrole/lignin composite electrode material2015In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 3, no 24, p. 12927-12937Article in journal (Refereed)
    Abstract [en]

    We report spectroelectrochemical studies to investigate the charge storage mechanism of composite polypyrrole/lignin electrodes. Renewable bioorganic electrode materials were produced by electropolymerization of pyrrole in the presence of a water-soluble lignin derivative acting as a dopant. The resulting composite exhibited enhanced charge storage abilities due to a lignin-based faradaic process, which was expressed after repeated electrochemical redox of the material. The in situ FTIR spectroelectrochemistry results show the formation of quinone groups, and reversible oxidation-reduction of these groups during charge-discharge experiments in the electrode materials. The most significant IR bands include carbonyl absorption near 1705 cm(-1), which is attributed to the creation of quinone moieties during oxidation, and absorption at 1045 cm(-1) which is due to hydroquinone moieties.

  • 45.
    Ajjan, Fátima
    et al.
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Khan, Ziyauddin
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Riera-Galindo, Sergi
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Lienemann, Samuel
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Vagin, Mikhail
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Petsagkourakis, Ioannis
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Gabrielsson, Roger
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Braun, Slawomir
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Fahlman, Mats
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Crispin, Xavier
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Doped Conjugated Polymer Enclosing a Redox Polymer: Wiring Polyquinones with Poly(3,4‐Ethylenedioxythiophene)2020In: Advanced Energy and Sustainability Research, E-ISSN 2699-9412, Vol. 1, no 2, article id 2000027Article in journal (Refereed)
    Abstract [en]

    The mass implementation of renewable energies is limited by the absence of efficient and affordable technology to store electrical energy. Thus, the development of new materials is needed to improve the performance of actual devices such as batteries or supercapacitors. Herein, the facile consecutive chemically oxidative polymerization of poly(1-amino-5-chloroanthraquinone) (PACA) and poly(3,4-ethylenedioxythiophene (PEDOT) resulting in a water dispersible material PACA-PEDOT is shown. The water-based slurry made of PACA-PEDOT nanoparticles can be processed as film coated in ambient atmosphere, a critical feature for scaling up the electrode manufacturing. The novel redox polymer electrode is a nanocomposite that withstands rapid charging (16 A g−1) and delivers high power (5000 W kg−1). At lower current density its storage capacity is high (198 mAh g−1) and displays improved cycling stability (60% after 5000 cycles). Its great electrochemical performance results from the combination of the redox reversibility of the quinone groups in PACA that allows a high amount of charge storage via Faradaic reactions and the high electronic conductivity of PEDOT to access to the redox-active sites. These promising results demonstrate the potential of PACA-PEDOT to make easily organic electrodes from a water-coating process, without toxic metals, and operating in non-flammable aqueous electrolyte for large scale pseudocapacitors. 

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  • 46.
    Ajjan, Fátima
    et al.
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Mecerreyes, David
    Univ Basque Country UPV EHU, Spain.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Enhancing Energy Storage Devices with Biomacromolecules in Hybrid Electrodes2019In: Biotechnology Journal, ISSN 1860-6768, E-ISSN 1860-7314, Vol. 14, no 12, article id 1900062Article, review/survey (Refereed)
    Abstract [en]

    The development of energy storage devices with higher energy and power outputs, and long cycling stability is urgently required in the pursuit of the expanding challenges of electrical energy storage. The utilization of biologically renewable redox compounds holds a great potential in designing sustainable energy storage systems and contributes in reducing the dependence on fossil fuels for energy materials. Quinones are the principal redox centers in natural organic materials and play a key role as charge storage electrode materials because of their abundance, multiple forms and integration into the materials flow through the biosphere. Electrical energy storage devices and systems can be significantly improved by the combination of scalable quinone-based biomaterials with good electronic conductors. This review uses recent examples to show how biopolymers are providing new directions in the development of renewable biohybrid electrodes for energy storage devices.

  • 47.
    Ajjan, Fátima
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Vagin, Mikhail
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Rebis, Tomasz
    Poznan Univ Tech, Poland.
    Ever Aguirre, Luis
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Ouyang, Liangqi
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Electronic and photonic materials. Linköping University, Faculty of Science & Engineering.
    Scalable Asymmetric Supercapacitors Based on Hybrid Organic/Biopolymer Electrodes2017In: ADVANCED SUSTAINABLE SYSTEMS, ISSN 2366-7486, Vol. 1, no 8, article id 1700054Article in journal (Refereed)
    Abstract [en]

    A trihybrid bioelectrode composed of lignin, poly(3,4-ethylenedioxythiophene) (PEDOT), and poly(aminoanthraquinone) (PAAQ) is prepared by a two-step galvanostatic electropolymerization, and characterized for supercapacitor applications. Using PEDOT/Lignin as a base layer, followed by the consecutive deposition of PAAQ, the hybrid electrode PEDOT/Lignin/PAAQ shows a high specific capacitance of 418 F g(-1) with small self-discharge. This trihybrid electrode material can be assembled into symmetric and asymmetric super-capacitors. The asymmetric supercapacitor uses PEDOT + Lignin/PAAQ as positive electrode and PEDOT/PAAQ as negative electrode, and exhibits superior electrochemical performance due to the synergistic effect of the two electrodes, which leads to a specific capacitance of 74 F g(-1). It can be reversibly cycled in the voltage range of 0-0.7 V. More than 80% capacitance is retained after 10 000 cycles. These remarkable features reveal the exciting potential of a full organic energy storage device with long cycle life.

  • 48.
    Ajjan Godoy, Fátima Nadia
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Biohybrid Polymer Electrodes for Renewable Energy Storage2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Daily and seasonally fluctuating energy supply and demand requires adequate energy storage solutions. In recent years electrochemical supercapacitors have attracted considerable attention due to their ability to both store and deliver electrical energy efficiently. Our efforts are focused on developing and optimizing sustainable organic electrode materials for supercapacitors based on renewable bioorganic materials, offering a cheap, environmentally friendly and scalable alternative to store energy. In particular, we are using the second most abundant biopolymer in nature, lignin (Lig), which is an insulating material. However, when used in combination with electroactive and conducting polymers such as polypyrrole (PPy) and poly(3,4-ethylenedioxythiophene) (PEDOT), the biohybrid electrodes PPy/Lig and PEDOT/Lig display significantly enhanced energy storage performance as compared to the pristine conducting polymers without the lignin. Redox cyclic voltammetry and galvanostatic charge/discharge measurements indicate that the enhanced performance is due to the additional pseudocapacitance generated by the quinone moieties in lignin. Moreover, a conjugated redoxpolymer poly(aminoanthraquinone) PAAQ, with intrinsic quinone functions and excellentstability, has been combined with lignin and PEDOT resulting in a trihybrid bioelectrode. PEDOT compensates the low conductivity of PAAQ and provides electrical pathways to the quinone groups. The electrochemically generated quinones undergo a two electron, two protonredox process within the biohybrid electrodes as revealed by FTIR spectroelectrochemistry.These remarkable features reveal the exciting potential of a full organic energy storage device with long cycle life. Therefore, supercapacitor devices were designed in symmetric or asymmetric two electrode configuration. The best electrochemical performance was achieved by the asymmetric supercapacitor based on PEDOT+Lignin/PAAQ as the positive electrode and PEDOT/PAAQ as the negative electrode. This device exhibits superior electrochemical performance and outstanding stability after 10000 charge/discharge cycles due to the synergistic effect of the two electrodes. Finally, we have characterized the response of this supercapacitor device when charged with the intermittent power supply from an organic photovoltaic module. We have designed charging/discharging conditions such that reserve power was available in the storage device at all times. This work has resulted in an inexpensive fully organic system witht he dual function of energy conversion and storage.

    List of papers
    1. Biopolymer hybrid electrodes for scalable electricity storage
    Open this publication in new window or tab >>Biopolymer hybrid electrodes for scalable electricity storage
    2016 (English)In: Materials Horizons, ISSN 2051-6347, E-ISSN 2051-6355, Vol. 3, no 3, p. 174-185Article, review/survey (Refereed) Published
    Abstract [en]

    Powering the future, while maintaining a cleaner environment and a strong socioeconomic growth, is going to be one of the biggest challenges faced by mankind in the 21st century. The first step in overcoming the challenge for a sustainable future is to use energy more efficiently so that the demand for fossil fuels can be reduced drastically. The second step is a transition from the use of fossil fuels to renewable energy sources. In this sense, organic electrode materials are becoming increasingly attractive compared to inorganic electrode materials which have reached a plateau regarding performance and have severe drawbacks in terms of cost, safety and environmental friendliness. Using organic composites based on conducting polymers, such as polypyrrole, and abundant, cheap and naturally occurring biopolymers rich in quinones, such as lignin, has recently emerged as an interesting alternative. These materials, which exhibit electronic and ionic conductivity, provide challenging opportunities in the development of new charge storage materials. This review presents an overview of recent developments in organic biopolymer composite electrodes as renewable electroactive materials towards sustainable, cheap and scalable energy storage devices.

    Place, publisher, year, edition, pages
    ROYAL SOC CHEMISTRY, 2016
    National Category
    Other Environmental Engineering
    Identifiers
    urn:nbn:se:liu:diva-128741 (URN)10.1039/c5mh00261c (DOI)000375296600002 ()
    Note

    Funding Agencies|Knut and Alice Wallenberg Foundation; Wallenberg Scholar grant

    Available from: 2016-05-31 Created: 2016-05-30 Last updated: 2017-11-30
    2. Spectroelectrochemical investigation of redox states in a polypyrrole/lignin composite electrode material
    Open this publication in new window or tab >>Spectroelectrochemical investigation of redox states in a polypyrrole/lignin composite electrode material
    Show others...
    2015 (English)In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 3, no 24, p. 12927-12937Article in journal (Refereed) Published
    Abstract [en]

    We report spectroelectrochemical studies to investigate the charge storage mechanism of composite polypyrrole/lignin electrodes. Renewable bioorganic electrode materials were produced by electropolymerization of pyrrole in the presence of a water-soluble lignin derivative acting as a dopant. The resulting composite exhibited enhanced charge storage abilities due to a lignin-based faradaic process, which was expressed after repeated electrochemical redox of the material. The in situ FTIR spectroelectrochemistry results show the formation of quinone groups, and reversible oxidation-reduction of these groups during charge-discharge experiments in the electrode materials. The most significant IR bands include carbonyl absorption near 1705 cm(-1), which is attributed to the creation of quinone moieties during oxidation, and absorption at 1045 cm(-1) which is due to hydroquinone moieties.

    Place, publisher, year, edition, pages
    ROYAL SOC CHEMISTRY, 2015
    National Category
    Materials Chemistry
    Identifiers
    urn:nbn:se:liu:diva-120069 (URN)10.1039/c5ta00788g (DOI)000356022800044 ()
    Note

    Funding Agencies|Knut and Alice Wallenberg foundation; Marie Curie network Renaissance; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009-00971]

    Available from: 2015-07-06 Created: 2015-07-06 Last updated: 2017-12-04
    3. High performance PEDOT/lignin biopolymer composites for electrochemical supercapacitors
    Open this publication in new window or tab >>High performance PEDOT/lignin biopolymer composites for electrochemical supercapacitors
    Show others...
    2016 (English)In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 4, no 5, p. 1838-1847Article in journal (Refereed) Published
    Abstract [en]

    Developing sustainable organic electrode materials for energy storage applications is an urgent task. We present a promising candidate based on the use of lignin, the second most abundant biopolymer in nature. This polymer is combined with a conducting polymer, where lignin as a polyanion can behave both as a dopant and surfactant. The synthesis of PEDOT/Lig biocomposites by both oxidative chemical and electrochemical polymerization of EDOT in the presence of lignin sulfonate is presented. The characterization of PEDOT/Lig was performed by UV-Vis-NIR spectroscopy, FTIR infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy, cyclic voltammetry and galvanostatic charge-discharge. PEDOT doped with lignin doubles the specific capacitance (170.4 F g(-1)) compared to reference PEDOT electrodes (80.4 F g(-1)). The enhanced energy storage performance is a consequence of the additional pseudocapacitance generated by the quinone moieties in lignin, which give rise to faradaic reactions. Furthermore PEDOT/Lig is a highly stable biocomposite, retaining about 83% of its electroactivity after 1000 charge/discharge cycles. These results illustrate that the redox doping strategy is a facile and straightforward approach to improve the electroactive performance of PEDOT.

    Place, publisher, year, edition, pages
    ROYAL SOC CHEMISTRY, 2016
    National Category
    Biological Sciences
    Identifiers
    urn:nbn:se:liu:diva-125323 (URN)10.1039/c5ta10096h (DOI)000368839200035 ()
    Note

    Funding Agencies|Power Papers project from the Knut and Alice Wallenberg foundation; Wallenberg Scholar grant from the Knut and Alice Wallenberg foundation; Marie Curie network Renaissance (NA); European Research Council by Starting Grant Innovative Polymers for Energy Storage (iPes) [306250]; Basque Government

    Available from: 2016-02-23 Created: 2016-02-19 Last updated: 2017-11-30
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  • 49.
    Akbar, Fariia Iasmin
    et al.
    Univ Bayreuth, Germany; Univ Bayreuth, Germany.
    Aslandukova, Alena
    Univ Bayreuth, Germany.
    Aslandukov, Andrey
    Univ Bayreuth, Germany; Univ Bayreuth, Germany.
    Yin, Yuqing
    Univ Bayreuth, Germany; Shandong Univ, Peoples R China.
    Trybel, Florian
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, Faculty of Science & Engineering.
    Khandarkhaeva, Saiana
    Univ Bayreuth, Germany.
    Fedotenko, Timofey
    Deutsch Elektronen Synchrotron DESY, Germany.
    Laniel, Dominique
    Univ Edinburgh, Scotland; Univ Edinburgh, Scotland.
    Bykov, Maxim
    Univ Cologne, Germany.
    Bykova, Elena
    Univ Bayreuth, Germany.
    Doubrovinckaia, Natalia
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, Faculty of Science & Engineering. Univ Bayreuth, Germany.
    Dubrovinsky, Leonid
    Univ Bayreuth, Germany.
    High-pressure synthesis of dysprosium carbides2023In: Frontiers in Chemistry, E-ISSN 2296-2646, Vol. 11, article id 1210081Article in journal (Refereed)
    Abstract [en]

    Chemical reactions between dysprosium and carbon were studied in laser-heated diamond anvil cells at pressures of 19, 55, and 58 GPa and temperatures of similar to 2500 K. In situ single-crystal synchrotron X-ray diffraction analysis of the reaction products revealed the formation of novel dysprosium carbides, Dy4C3 and Dy3C2, and dysprosium sesquicarbide Dy2C3 previously known only at ambient conditions. The structure of Dy4C3 was found to be closely related to that of dysprosium sesquicarbide Dy2C3 with the Pu2C3-type structure. Ab initio calculations reproduce well crystal structures of all synthesized phases and predict their compressional behavior in agreement with our experimental data. Our work gives evidence that high-pressure synthesis conditions enrich the chemistry of rare earth metal carbides.

  • 50.
    Aleckovic, Ehlimana
    et al.
    Linköping University, Department of Physics, Chemistry and Biology.
    Andersson, Linnea
    Linköping University, Department of Physics, Chemistry and Biology.
    Chamoun, Sherley
    Linköping University, Department of Physics, Chemistry and Biology.
    Einarsson, Ellen
    Linköping University, Department of Physics, Chemistry and Biology.
    Ekstedt, Ebba
    Linköping University, Department of Physics, Chemistry and Biology.
    Eriksen, Emma
    Linköping University, Department of Physics, Chemistry and Biology.
    Madan-Andersson, Maria
    Linköping University, Department of Physics, Chemistry and Biology.
    Method Development for Determining the Stability of Heat Stable Proteins Combined with Biophysical Characterization of Human Calmodulin and the Disease Associated Variant D130G2016Independent thesis Basic level (degree of Bachelor), 10,5 credits / 16 HE creditsStudent thesis
    Abstract [en]

    Calmodulin is a highly conserved calcium ion binding protein expressed in all eukaryotic species. The 149 amino acid residues in the primary structure are organized in seven α helices with the highly flexible central α helix connecting the two non-cooperative domains of calmodulin. Each domain contains two EF-hand motifs to which calcium ions bind in a cooperative manner, hence the binding of four calcium ions saturate one calmodulin molecule. In the cardiovascular area calmodulin is involved in the activation of cardiac muscle contraction, and mutations that arise in the genetic sequence of the protein often have severe consequences. One such consequential mutation that can arise brings about the replacement of the highly conserved aspartic acid with glycine at position 130 in the amino acid sequence. In this research, the thermal and chemical stability within the C domain of the D130G variant of human calmodulin was investigated using a new method only requiring circular dichroism spectroscopic measurements. Affinity studies within the C domain of the D130G variant of human calmodulin were performed using fluorescence spectroscopy, and the ligands chosen for this purpose were trifluoperazine and p- HTMI. All analytical experiments were performed with the C domain of wild type human calmodulin as a reference. From the new method, it was concluded that the C domain of the D130G variant of human calmodulin has a slightly decreased stability in terms of Tm and Cm values compared to the C domain of wild type human calmodulin. The affinity analyses indicated that neither trifluoperazine nor p-HTMI discriminates between the C domain of the D130G variant of human calmodulin and the C domain of wild type human calmodulin in terms of dissociation constants. The pivotal outcome from this research is that the new method is applicable for determination of the stability parameters Tm and Cm of heat stable proteins. 

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