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  • 51.
    Abrikosov, Igor
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska högskolan.
    Liot, Francois
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska högskolan.
    Marten, Tobias
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska högskolan.
    Smirnova, E. A.
    Theoretical Physics Department, Moscov Steel and Alloys Institute, Moscow, Russia.
    Magnetism in systems with reduced dimensionality and chemical disorder: the local environment effects2006Ingår i: Journal of Magnetism and Magnetic Materials, ISSN 0304-8853, E-ISSN 1873-4766, Vol. 300, nr 1, s. 211-215Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We study influence of the local chemical environment, the so-called local environment effects, on the electronic structure and properties of magnetic systems with reduced dimensionality and chemical disorder, and show that they play a crucial role in a vicinity of magnetic instability. As a model, we consider Fe–Ni Invar. We present results obtained from ab initio calculations of the electronic structure, magnetic moments, and exchange interactions in random fcc Fe–Ni alloy, for a single monolayer alloy film on a Cu (0 0 1) substrate as well as in the bulk. We analyze the difference between the film and the bulk magnetization, which is found to be most pronounced for dilute alloys. We also analyze a sensitivity of the individual magnetic moments and effective exchange parameters to the local chemical environment of the atoms.

  • 52.
    Abrikosov, Igor
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska högskolan.
    Marten, Tobias
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska högskolan.
    Olovsson, Weine
    Condensed Matter Theory Group, Department of Physics, Uppsala University, SE-751 21 Uppsala, Sweden.
    Local environment effects in random metallic alloys2005Ingår i: The Science of Complex Alloy Phases: proceedings of a symposium held during the TMS Annual Meeting and Exhibition in San Francisco, California, USA, February 13-17, 2005, to honor the Wiliam Hume-Rothery Award recipient Professor Uichiro Mizutani / [ed] Thaddeus B. Massalski and Patrice E. A. Turchi, USA: TMS , 2005, 1, s. 87-108Kapitel i bok, del av antologi (Övrigt vetenskapligt)
    Abstract [en]

    This book is published in honor of the 2005 Hume-Rothery Award Recipient, Uichiro Mizutani. It emphasizes both theoretical and experimental aspects of electronic, structural, and thermodynamic properties of complex alloy phases. Leading experts provide an assessment of our current understanding of the structural properties of complex materials, including quasicrystalline and amorphous alloys. Special emphasis is placed on our understanding of why nature is able to stabilize complex atomic arrangements and on recent results related to structurally complex alloy phases. These topics, in the spirit of the work carried out by U. Mizutani, constitute the main theme of the book

  • 53.
    Abrikosov, Igor
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik.
    Marten, Tobias
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik.
    Olsson, P.
    Uppsala University.
    Simak, Sergey
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik.
    Electronic theory of materials properties: from fundamental understanding towards materials design2006Rapport (Övrigt vetenskapligt)
    Abstract [en]

           

  • 54.
    Abrikosov, Igor
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik.
    Mikhaylushkin, Arkady
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik.
    Asker, Christian
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik.
    Simak, Sergey
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik.
    Ab initio modeling of alloying effects at extreme conditions2008Ingår i: Second EuroMinScI Conference,2008, France: ESF , 2008Konferensbidrag (Refereegranskat)
    Abstract [en]

       

  • 55.
    Abrikosov, Igor
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska högskolan.
    Nikonov, A. Yu
    Russian Academic Science, Russia .
    Ponomareva, A. V.
    National University of Science and Technology MISiS, Russia .
    Dmitriev, A. I.
    Russian Academic Science, Russia National Research Tomsk State University, Russia .
    Barannikova, S. A.
    Russian Academic Science, Russia National Research Tomsk State University, Russia .
    Theoretical Modeling of Thermodynamic and Mechanical Properties of the Pure Components of Ti and Zr Based Alloys Using the Exact Muffin-Tin Orbitals Method2014Ingår i: Russian Physics Journal, ISSN 1064-8887, E-ISSN 1573-9228, Vol. 56, nr 9, s. 1030-1038Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The exact muffin-tin orbitals (EMTO) method belongs to the third and latest generation of first-principles methods of calculating the electronic structure of materials in the so-called approximation of muffin-tin (MT) orbitals within the framework of the density functional theory. A study has been performed of its applicability for modeling the thermodynamic and mechanical properties of the pure components of Ti and Zr based alloys. The total energies of Ti, Zr, Nb, V, Mo, and Al are calculated in three crystal structures - face-centered cubic (FCC), body-centered cubic (BCC), and hexagonal close-packed (HCP). For all of these elements and crystal structures, we have calculated the theoretical values of the lattice constants, elastic constants, and equations of state. The stable crystal structures have been determined. In all cases, calculations by the EMTO method predict the correct structure of the ground state. For stable structures we compared the obtained results with experiment and with calculations using full potential methods. We have demonstrated the reliability of the EMTO method and conclude that its further application for effective modeling of the properties of disordered alloys based on Ti and Zr is possible.

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  • 56.
    Abrikosov, Igor
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska högskolan.
    Olovsson, W.
    Uppsala University.
    Wallenius, J.
    Royal Institute of Technology.
    Ab initio simuleringar av materialegenskaper: från grundläggande teori mot design av material2004Ingår i: Nytt från NSC, nr 19, s. 3-5Artikel i tidskrift (Övrig (populärvetenskap, debatt, mm))
  • 57.
    Abrikosov, Igor
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska högskolan. NUST MISIS, Russia.
    Ponomareva, A. V.
    NUST MISIS, Russia.
    Nikonov, A. Yu.
    National Research Tomsk State University, Russia; SB RAS, Russia.
    Zharmukhambetova, A. M.
    National Research Tomsk State University, Russia.
    Mosyagin, Igor
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska högskolan. NUST MISIS, Russia.
    Lugovskoy, A. V.
    NUST MISIS, Russia.
    Hellman, Olle
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska högskolan.
    Lind, Hans
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska högskolan.
    Dmitriev, A. I.
    National Research Tomsk State University, Russia; SB RAS, Russia.
    Barannikova, S. A.
    National Research Tomsk State University, Russia; SB RAS, Russia.
    Theoretical description of pressure-induced phase transitions: a case study of Ti-V alloys2015Ingår i: High Pressure Research, ISSN 0895-7959, E-ISSN 1477-2299, Vol. 35, nr 1, s. 42-48Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We discuss theoretical description of pressure-induced phase transitions by means of first-principles calculations in the framework of density functional theory. We illustrate applications of theoretical tools that allow one to take into account configurational and vibrational disorders, considering Ti-V alloys as a model system. The universality of the first-principles theory allows us to apply it in studies of different phenomena that occur in the Ti-V system upon compression. Besides the transitions between different crystal structures, we discuss isostructural transitions in bcc Ti-V alloys. Moreover, we present arguments for possible electronic transitions in this system, which may explain peculiar behaviour of elastic properties of V upon compression.

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  • 58.
    Abrikosov, Igor
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska fakulteten. National University of Science and Technology MISIS, Russia.
    Ponomareva, A. V.
    National University of Science and Technology MISIS, Russia.
    Steneteg, Peter
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Barannikova, S. A.
    National University of Science and Technology MISIS, Russia; National Research Tomsk State University, Russia; SB RAS, Russia.
    Alling, Björn
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Recent progress in simulations of the paramagnetic state of magnetic materials2016Ingår i: Current opinion in solid state & materials science, ISSN 1359-0286, E-ISSN 1879-0348, Vol. 20, nr 2, s. 85-106Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    We review recent developments in the field of first-principles simulations of magnetic materials above the magnetic order disorder transition temperature, focusing mainly on 3d-transition metals, their alloys and compounds. We review theoretical tools, which allow for a description of a system with local moments, which survive, but become disordered in the paramagnetic state, focusing on their advantages and limitations. We discuss applications of these theories for calculations of thermodynamic and mechanical properties of paramagnetic materials. The presented examples include, among others, simulations of phase stability of Fe, Fe-Cr and Fe-Mn alloys, formation energies of vacancies, substitutional and interstitial impurities, as well as their interactions in Fe, calculations of equations of state and elastic moduli for 3d-transition metal alloys and compounds, like CrN and steels. The examples underline the need for a proper treatment of magnetic disorder in these systems. (C) 2015 Elsevier Ltd. All rights reserved.

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  • 59. Beställ onlineKöp publikationen >>
    Abrikossova, Natalia
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär ytfysik och nanovetenskap. Linköpings universitet, Tekniska fakulteten.
    Investigation of nanoparticle-cell interactions for development of next generation of biocompatible MRI contrast agents2018Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    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.

    Delarbeten
    1. Effects of gadolinium oxide nanoparticles on the oxidative burst from human neutrophil granulocytes
    Öppna denna publikation i ny flik eller fönster >>Effects of gadolinium oxide nanoparticles on the oxidative burst from human neutrophil granulocytes
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    2012 (Engelska)Ingår i: Nanotechnology, ISSN 0957-4484, E-ISSN 1361-6528, Vol. 23, nr 27, s. 275101-Artikel i tidskrift (Refereegranskat) 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.

    Ort, förlag, år, upplaga, sidor
    Institute of Physics, 2012
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:liu:diva-79667 (URN)10.1088/0957-4484/23/27/275101 (DOI)000305802000001 ()
    Tillgänglig från: 2012-08-14 Skapad: 2012-08-13 Senast uppdaterad: 2022-02-07
    2. Synthesis and Characterization of PEGylated Gd2O3 Nanoparticles for MRI Contrast Enhancement
    Öppna denna publikation i ny flik eller fönster >>Synthesis and Characterization of PEGylated Gd2O3 Nanoparticles for MRI Contrast Enhancement
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    2010 (Engelska)Ingår i: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 26, nr 8, s. 5753-5762Artikel i tidskrift (Refereegranskat) 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.

    Ort, förlag, år, upplaga, sidor
    American Chemical Society (ACS), 2010
    Nationell ämneskategori
    Naturvetenskap
    Identifikatorer
    urn:nbn:se:liu:diva-54946 (URN)10.1021/la903566y (DOI)000276562300061 ()
    Tillgänglig från: 2010-04-23 Skapad: 2010-04-23 Senast uppdaterad: 2022-02-07Bibliografiskt granskad
    3. Gd2O3 nanoparticles in hematopoietic cells for MRI contrast enhancement
    Öppna denna publikation i ny flik eller fönster >>Gd2O3 nanoparticles in hematopoietic cells for MRI contrast enhancement
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    2011 (Engelska)Ingår i: International journal of nano medicine, ISSN 1178-2013, Vol. 6, s. 3233-3240Artikel i tidskrift (Refereegranskat) 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.

    Ort, förlag, år, upplaga, sidor
    Manchester, UK: Dove Medical Press Ltd, 2011
    Nyckelord
    gadolinium oxide, magnetic resonance imaging, contrast agent, cell labeling, Ba/F3 cells, THP-1 cells
    Nationell ämneskategori
    Medicin och hälsovetenskap
    Identifikatorer
    urn:nbn:se:liu:diva-72275 (URN)10.2147/IJN.S23940 (DOI)000298164300001 ()
    Anmärkning

    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)||

    Tillgänglig från: 2011-11-24 Skapad: 2011-11-24 Senast uppdaterad: 2021-10-13
    4. Synthesis and Characterization of Tb3+-Doped Gd2O3 Nanocrystals: A Bifunctional Material with Combined Fluorescent Labeling and MRI Contrast Agent Properties
    Öppna denna publikation i ny flik eller fönster >>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 (Engelska)Ingår i: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 113, nr 17, s. 6913-6920Artikel i tidskrift (Refereegranskat) 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.

    Nationell ämneskategori
    Naturvetenskap
    Identifikatorer
    urn:nbn:se:liu:diva-12944 (URN)10.1021/jp808708m (DOI)000265529700009 ()
    Anmärkning

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

    Tillgänglig från: 2008-02-21 Skapad: 2008-02-21 Senast uppdaterad: 2021-10-13Bibliografiskt granskad
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    Investigation of nanoparticle-cell interactions for development of next generation of biocompatible MRI contrast agents
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  • 60.
    Abrikossova, Natalia
    Linköpings universitet, Institutionen för fysik, kemi och biologi.
    In-vitro studier av inflammatorisk svar från helblod och neutrofila granulocyter vid aktivering med nanopartiklar2007Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats
    Abstract [sv]

    Syftet med detta arbete var att studera inflammatoriska effekter i mänskligt helblod och neutrofila granulocyter exponerade och stimulerade av nanopartiklar av gadoliniumoxid. Projektet utreder den toxiska potentialen hos nanopartiklar med olika kemiska och morfologiska egenskaper.

    I experimenten undersöktes cellresponsen hos blodceller exponerade med ofunktionaliserade och funktionaliserade nanopartiklarna. Effekterna av funktionaliserade och ofunktionaliserade nanopartiklarna på aggregation och syreradikalproduktion i helblod och hos neutrofila granulocyter studerades med hjälp av lumi-aggregometri.

    Studier har visat att varken ofunktionaliserade eller funktionaliserade nanopartiklarna ger aggregation i blodet. Syreradikalproduktionen ökar däremot. Resultaten av studier i helblod visar att stimulering med spädnings serier av funktionaliserade nanopartiklar ger mindre frisättning av syreradikaler än spädnings serier med ofunktionaliserade nanopartiklar. Detta bekräftas med studier av morfologiska skillnader i neutrofila granulocyter som var stimulerade med olika typer av nanopartiklar. Detta gjordes med hjälp av fluorescensmikroskopi. Resultaten från studierna tyder på att funktionaliserade nanopartiklar är mindre inflammatoriska än ofunktionaliserade nanopartiklar.

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  • 61.
    Abrikossova, Natalia
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär ytfysik och nanovetenskap. Linköpings universitet, Tekniska fakulteten.
    Skoglund, Caroline
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär ytfysik och nanovetenskap. Linköpings universitet, Tekniska högskolan.
    Ahrén, Maria
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär ytfysik och nanovetenskap. Linköpings universitet, Tekniska fakulteten.
    Bengtsson, Torbjorn
    University of Örebro, Sweden .
    Uvdal, Kajsa
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär ytfysik och nanovetenskap. Linköpings universitet, Tekniska fakulteten.
    Effects of gadolinium oxide nanoparticles on the oxidative burst from human neutrophil granulocytes2012Ingår i: Nanotechnology, ISSN 0957-4484, E-ISSN 1361-6528, Vol. 23, nr 27, s. 275101-Artikel i tidskrift (Refereegranskat)
    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.

  • 62.
    Abtahi, Jahan
    et al.
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Ortopedi och idrottsmedicin. Linköpings universitet, Hälsouniversitetet.
    Tengvall, Pentti
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad Fysik. Linköpings universitet, Tekniska högskolan. Department of Biomaterials, Institute of Clinical Sciences, Sahlgrenska Academy, Gothenburg, Sweden.
    Aspenberg, Per
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Ortopedi och idrottsmedicin. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Ortopedicentrum, Ortopedkliniken Linköping.
    Bisphosphonate coating might improve fixation of dental implants in the maxilla: A pilot study2010Ingår i: International Journal of Oral and Maxillofacial Surgery, ISSN 0901-5027, E-ISSN 1399-0020, Vol. 39, nr 7, s. 673-677Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This pilot study evaluates the clinical stability of bisphosphonate-coated dental implants placed using a two-stage surgical procedure in five patients. Each patient received seven regular Branemark implants, one of which was coated with bisphosphonate in a fibrinogen matrix. The coated implant was inserted where the bone was expected to have the least favourable quality. The level of the marginal bone around each implant was measured by intraoral periapical radiographs and implant stability was recorded using resonance frequency measurements. Frequency values (ISQ) were obtained peroperatively before flap closure and after 6 months at abutment connection. At abutment connection the bisphosphonate-coated implants were removed en bloc in two patients for histological examination. An animal experiment had previously confirmed that gamma-sterilization did not reduce bioactivity of the bisphosphonate coating. In each patient, the bisphosphonate-coated implant showed the largest improvement in ISQ level of all implants. Their values at the start tended to be lower, and the absolute value at 6 months did not differ. No complications occurred with the coated implants. Histology showed no abnormalities. Improvement in ISQ values was an expected effect of the bisphosphonate coating, but could be due to the choice of insertion site. This finding warrants a randomized blinded study.

  • 63.
    Acevedo, Juan Pablo
    et al.
    Univ Los Andes, Chile; Cells Cells, Chile.
    Angelopoulos, Ioannis
    Univ Los Andes, Chile; Cells Cells, Chile.
    van Noort, Danny
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teknisk biologi. Linköpings universitet, Tekniska fakulteten. Univ Los Andes, Chile.
    Khoury, Maroun
    Univ Los Andes, Chile; Cells Cells, Chile; Consorcio Regenero, Chile.
    Microtechnology applied to stem cells research and development2018Ingår i: Regenerative Medicine, ISSN 1746-0751, E-ISSN 1746-076X, Vol. 13, nr 2, s. 233-248Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    Microfabrication and microfluidics contribute to the research of cellular functions of cells and their interaction with their environment. Previously, it has been shown that microfluidics can contribute to the isolation, selection, characterization and migration of cells. This review aims to provide stem cell researchers with a toolkit of microtechnology (mT) instruments for elucidating complex stem cells functions which are challenging to decipher with traditional assays and animal models. These microdevices are able to investigate about the differentiation and niche interaction, stem cells transcriptomics, therapeutic functions and the capture of their secreted microvesicles. In conclusion, microtechnology will allow a more realistic assessment of stem cells properties, driving and accelerating the translation of regenerative medicine approaches to the clinic.

  • 64.
    Ackelid, Ulf
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad Fysik. Linköpings universitet, Tekniska högskolan.
    Armgarth, M.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad Fysik. Linköpings universitet, Tekniska högskolan.
    Spetz, Anita
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad Fysik. Linköpings universitet, Tekniska högskolan.
    Lundström, Ingemar
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad Fysik. Linköpings universitet, Tekniska högskolan.
    Ethanol sensitivity of palladium-gate metal-oxide-semiconductor structures1986Ingår i: IEEE Electron Device Letters, ISSN 0741-3106, E-ISSN 1558-0563, Vol. 7, nr 6, s. 353-355Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Hydrogen-sensitive palladium-gate MOS structures heated above 150°C show sensitivity to ethanol vapor. The effect is probably due to catalytic dehydrogenation of adsorbed ethanol molecules on the surface of the palladium gate.

  • 65.
    Ackelman, Emma
    Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Cognitive Judgement Bias as an Indicator for Animal Welfare2020Självständigt arbete på grundnivå (kandidatexamen), 10,5 poäng / 16 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Animal welfare has long been a subject under debate. Since animals are unable to voice concerns about their living standards it is of interest to find other ways to secure their wellbeing. A new measurement has been introduced where animals’ own judgement can act as an indicator for their emotional state and welfare. This study summarizes key elements from previous literature and research in order to explain the connection between welfare and judgement bias. Emotions have been defined as either an observable reaction to a stimulus or a subjective conscious experience of the stimulus. The second has been difficult to assess in animals since they cannot vocalise their own interpretations, hence emotions in animals are assessed based on the first definition. The study of animal welfare is in short the study of animal’s judgement of the world, which in turn indicate how animals feel. Cognitive judgement bias has been defined as whether an animal assess an ambiguous stimulus as negative or positive, a common method used to demonstrate this concept is the go no-go method. Animals learn to discriminate between two stimuli and is then presented with an ambiguous stimulus. The response to the ambiguous stimulus is recorded and determine if the animal is optimistic or pessimistic in its judgement. Research has been rather successful in determining factors which can affect animal welfare, opening up for deeper discussions concerning animal cognition, awareness and their effect on welfare, but further refinements are required to assess the influence of judgement bias.

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    fulltext
  • 66.
    Ackelman, Jenny
    Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Alternative splicing and its regulation under normal and abnormal conditions2010Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    During the maturation of pre-mRNA introns are removed and exons are spliced together, to form a primary transcript, a reaction that is catalyzed by the spliceosome. Alternative splicing is a complex reaction that mainly utilizes one of four mechanisms; exon skipping, 5’ splice site choice, 3’ splice site choice and intron retention. To achieve accurate splicing four sequence elements are essential, two of which are located in the splice sites themselves; 5’ splice sites and 3’ splice sites, but also the polypyrimidine tract and the branch point sequence. Alternative splicing can be regulated by histone or chromatin modulations, siRNA, transcription efficiency and various proteins, many of which belong to either the SR protein family or the hnRNP family of proteins. SR proteins usually promote exon inclusion, while hnRNP proteins usually promote exon skipping. There are also regulatory elements that are called exonic splicing enhancers or silencers depending on if they promote or inhibit the inclusion of the exon they reside in. These elements also exist in introns and are then called intronic splicing enhancers or silencers. The enhancer elements are most commonly targeted by SR proteins and the silencer elements are usually targeted by hnRNP proteins. This paper will mainly focus on the regulation of alternative splicing and the role of alternative splicing under abnormal conditions, such as when mutations cause disease.

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    FULLTEXT01
  • 67.
    Adair, R.K.
    et al.
    Department of Physics, Yale University, PO Box 208121, New Haven, CT 06520-8121, United States.
    Sernelius, Bo
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik.
    Balzano, Q.
    Dept. of Elec. and Comp. Engineering, A.V. Williams Building, University of Maryland, College Park, MD 20742, United States.
    Comment on "Possible induced enhancement of dispersion forces by cellular phones" by B. E. Sernelius, Phys. Chem. Chem. Phys., 2004, 6, 13632004Ingår i: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 6, nr 14, s. 3915-3918s. 1363-Artikel i tidskrift (Övrigt vetenskapligt)
    Abstract [en]

    [No abstract available]

  • 68.
    Adam, Rania Elhadi
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik, elektroteknik och matematik. Linköpings universitet, Tekniska fakulteten.
    Alnoor, Hatim
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska fakulteten.
    Pozina, Galia
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Liu, Xianjie
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Willander, Magnus
    Linköpings universitet, Tekniska fakulteten. Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik, elektroteknik och matematik.
    Nur, Omer
    Linköpings universitet, Tekniska fakulteten. Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik, elektroteknik och matematik.
    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 light2020Ingår i: Solid State Sciences, ISSN 1293-2558, E-ISSN 1873-3085, Vol. 99, artikel-id 106053Artikel i tidskrift (Refereegranskat)
    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.

  • 69.
    Adam, Rania Elhadi
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik, elektroteknik och matematik. Linköpings universitet, Tekniska fakulteten.
    Chalangar, Ebrahim
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik, elektroteknik och matematik. Linköpings universitet, Tekniska fakulteten. School of Information Technology, Halmstad University, Halmstad, Sweden.
    Pirhashemi, Mahsa
    Department of Chemistry, Faculty of Sciences, University of Mohaghegh Ardabili, Ardabil, Iran.
    Pozina, Galia
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Liu, Xianjie
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ytors Fysik och Kemi. Linköpings universitet, Tekniska fakulteten.
    Palisaitis, Justinas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Pettersson, Håkan
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik, elektroteknik och matematik. Linköpings universitet, Tekniska fakulteten. School of Information Technology, Halmstad University, Halmstad, Sweden; Solid State Physics and NanoLund, Lund University, Lund, Sweden.
    Willander, Magnus
    Linköpings universitet, Tekniska fakulteten. Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik, elektroteknik och matematik.
    Nur, Omer
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik, elektroteknik och matematik. Linköpings universitet, Tekniska fakulteten.
    Graphene-based plasmonic nanocomposites for highly enhanced solar-driven photocatalytic activities2019Ingår i: RSC Advances, E-ISSN 2046-2069, Vol. 9, nr 52, s. 30585-30598Artikel i tidskrift (Refereegranskat)
    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.

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  • 70.
    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
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten. 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 systems2017Ingår i: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 421, s. 843-851Artikel i tidskrift (Refereegranskat)
    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.

  • 71. Beställ onlineKöp publikationen >>
    Adamovic, Dragan
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska högskolan.
    Molecular Dynamics Studies of Low-Energy Atom Impact Phenomena on Metal Surfaces during Crystal Growth2006Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    It is a well-known fact in the materials science community that the use of low-energy atom impacts during thin film deposition is an effective tool for altering the growth behavior and for increasing the crystallinity of the films. However, the manner in which the incident atoms affect the growth kinetics and surface morphology is quite complicated and still not fully understood. This provides a strong incentive for further investigations of the interaction among incident atoms and surface atoms on the atomic scale. These impact-induced energetic events are non-equilibrium, transient processes which complete in picoseconds. The only accessible technique today which permits direct observation of these events is molecular dynamics (MD) simulations.

    This thesis deals with MD simulations of low-energy atom impact phenomena on metal surfaces during crystal growth. Platinum is chosen as a model system given that it has seen extended use as a model surface over the past few decades, both in experiments and simulations. In MD, the classical equations of motion are solved numerically for a set of interacting atoms. The atomic interactions are calculated using the embedded atom method (EAM). The EAM is a semi-empirical, pair-functional interatomic potential based on density functional theory. This potential provides a physical picture that includes many-atom effects while retaining computational efficiency needed for larger systems.

    Single adatoms residing on a surface constitute the smallest possible clusters and are the fundamental components controlling nucleation kinetics. Small two-dimensional clusters on a surface are the result of nucleation and are present during the early stages of growth. These surface structures are chosen as targets in the simulations (papers I and II) to provide further knowledge of the atomistic processes which occur during deposition, to investigate at which impact energies the different kinetic pathways open up, and how they may affect growth behavior. Some of the events observed are adatom scattering, dimer formation, cluster disruption, formation of three-dimensional clusters, and residual vacancy formation. Given the knowledge obtained, papers III and IV deal with growth of several layers with the aim to study the underlying mechanisms responsible for altering growth behavior and how the overall intra- and interlayer atomic migration can be controlled by low-energy atom impacts.

    Delarbeten
    1. Low-energy ion irradiation during film growth: Kinetic pathways leading to enhanced adatom migration rates
    Öppna denna publikation i ny flik eller fönster >>Low-energy ion irradiation during film growth: Kinetic pathways leading to enhanced adatom migration rates
    Visa övriga...
    2005 (Engelska)Ingår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 86, s. 211915-Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Embedded-atom molecular dynamics simulations are used to investigate the effects of low-energy self-ion irradiation of Pt adatoms on Pt(111). Here, we concentrate on self-bombardment dynamics, i.e., isolating and monitoring the atomic processes, induced by normally incident Pt atoms with energies E ranging from 5 to 50 eV, that can affect intra- and interlayer mass transport.. We find that adatom scattering, surface channeling, and dimer formation occur at all energies. Atomic intermixing events involving incident and terrace atoms are observed at energies 15  eV, while the collateral formation of residual surface vacancies is observed only with E>40  eV. The overall effect of low-energy self-ion irradiation is to enhance lateral adatom and terrace atom migration. ©2005 American Institute of Physics

    Nyckelord
    platinum, adsorbed layers, ion beam effects, molecular dynamics method, channelling, vacancies (crystal), diffusion, metallic thin films, surface structure
    Nationell ämneskategori
    Naturvetenskap
    Identifikatorer
    urn:nbn:se:liu:diva-13934 (URN)10.1063/1.1940122 (DOI)
    Tillgänglig från: 2006-08-29 Skapad: 2006-08-29 Senast uppdaterad: 2017-12-13
    2. Enhanced intra- and interlayer mass transport on Pt(111) via 5 - 50 eV Pt atom impacts on two-dimensional Pt clusters
    Öppna denna publikation i ny flik eller fönster >>Enhanced intra- and interlayer mass transport on Pt(111) via 5 - 50 eV Pt atom impacts on two-dimensional Pt clusters
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    2006 (Engelska)Ingår i: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 515, nr 4, s. 2235-2243Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Embedded-atom molecular dynamics simulations were used to investigate the effects of low-energy (5–50 eV) normally-incident self-ion irradiation of two-dimensional compact Pt3, Pt7, Pt19, and Pt37 clusters on Pt(111). We follow atomistic pathways leading to bombardment-induced intra- and interlayer mass transport. The results can be described in terms of three impact energy regimes. With E ≤ 20 eV, we observe an increase in 2D island dimensions and negligible residual point defect formation. As the impact energy is raised above 20 eV, we observe an increase in irradiation-induced lateral mass transport, a decrease in island size, and the activation of interlayer processes. For E ≥ 35 eV, this trend continues, but point defects, in the form of surface vacancies, are also formed. The results illustrate the richness of the dynamical interaction mechanisms occurring among incident energetic species, target clusters, and substrate atoms, leading to island preservation, reconfiguration, disruption and/or residual point defects formation. We discuss the significance of these results in terms of thin film growth.

    Nyckelord
    Ion bombardment; Platinum; Clusters; Atomistic dynamics
    Nationell ämneskategori
    Naturvetenskap
    Identifikatorer
    urn:nbn:se:liu:diva-13935 (URN)10.1016/j.tsf.2006.05.028 (DOI)
    Tillgänglig från: 2006-08-29 Skapad: 2006-08-29 Senast uppdaterad: 2017-12-13
    3. Kinetic pathways leading to layer-by-layer growth from hyperthermal atoms: A Multibillion time step molecular dynamics study
    Öppna denna publikation i ny flik eller fönster >>Kinetic pathways leading to layer-by-layer growth from hyperthermal atoms: A Multibillion time step molecular dynamics study
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    2007 (Engelska)Ingår i: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 76, s. 115418-115425Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    We employ multibillion time step embedded-atom molecular dynamics simulations to investigate the homoepitaxial growth of Pt(111) from hyperthermal Pt atoms (EPt=0.2–50eV) using deposition fluxes approaching experimental conditions. Calculated antiphase diffraction intensity oscillations, based on adatom coverages as a function of time, reveal a transition from a three-dimensional multilayer growth mode with EPt<20eV to a layer-by-layer growth with EPt≥20eV. We isolate the effects of irradiation-induced processes and thermally activated mass transport during deposition in order to identify the mechanisms responsible for promoting layer-by-layer growth. Direct evidence is provided to show that the observed transition in growth modes is primarily due to irradiation-induced processes which occur during the 10ps following the arrival of each hyperthermal atom. The kinetic pathways leading to the transition involve both enhanced intralayer and interlayer adatom transport, direct incorporation of energetic atoms into clusters, and cluster disruption leading to increased terrace supersaturation.

    Ort, förlag, år, upplaga, sidor
    American Physical Society, 2007
    Nationell ämneskategori
    Naturvetenskap
    Identifikatorer
    urn:nbn:se:liu:diva-38795 (URN)10.1103/PhysRevB.76.115418 (DOI)45667 (Lokalt ID)45667 (Arkivnummer)45667 (OAI)
    Anmärkning

    The previous status of this article was Manuscript.

    Tillgänglig från: 2009-10-10 Skapad: 2009-10-10 Senast uppdaterad: 2017-12-13Bibliografiskt granskad
    4. Controlled intra- and interlayer mass transport during low-energy Pt(111) homoepitaxy
    Öppna denna publikation i ny flik eller fönster >>Controlled intra- and interlayer mass transport during low-energy Pt(111) homoepitaxy
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    (Engelska)Manuskript (Övrigt vetenskapligt)
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:liu:diva-13937 (URN)
    Tillgänglig från: 2006-08-29 Skapad: 2006-08-29 Senast uppdaterad: 2014-04-14
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  • 72.
    Adamovic, Dragan
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik.
    Chirita, Valeriu
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik.
    Münger, Peter
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik.
    Hultman, Lars
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik.
    Greene, J.E.
    Materials Science Department and the Frederick Seitz Materials Research Laboratory, University of Illinois, Urbana, USA.
    Kinetic pathways leading to layer-by-layer growth from hyperthermal atoms: A Multibillion time step molecular dynamics study2007Ingår i: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 76, s. 115418-115425Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We employ multibillion time step embedded-atom molecular dynamics simulations to investigate the homoepitaxial growth of Pt(111) from hyperthermal Pt atoms (EPt=0.2–50eV) using deposition fluxes approaching experimental conditions. Calculated antiphase diffraction intensity oscillations, based on adatom coverages as a function of time, reveal a transition from a three-dimensional multilayer growth mode with EPt<20eV to a layer-by-layer growth with EPt≥20eV. We isolate the effects of irradiation-induced processes and thermally activated mass transport during deposition in order to identify the mechanisms responsible for promoting layer-by-layer growth. Direct evidence is provided to show that the observed transition in growth modes is primarily due to irradiation-induced processes which occur during the 10ps following the arrival of each hyperthermal atom. The kinetic pathways leading to the transition involve both enhanced intralayer and interlayer adatom transport, direct incorporation of energetic atoms into clusters, and cluster disruption leading to increased terrace supersaturation.

  • 73.
    Adamovic, Dragan
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Chirita, Valeriu
    Münger, Peter
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska högskolan.
    Hultman, Lars
    Greene, Joe
    Controlled intra- and interlayer mass transport during low-energy Pt(111) homoepitaxyManuskript (Övrigt vetenskapligt)
  • 74.
    Adamovic, Dragan
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska högskolan.
    Chirita, Valeriu
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Münger, Peter
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska högskolan.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Greene, Joe
    University of Illinois.
    Enhanced intra- and interlayer mass transport on Pt(111) via 5 - 50 eV Pt atom impacts on two-dimensional Pt clusters2006Ingår i: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 515, nr 4, s. 2235-2243Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Embedded-atom molecular dynamics simulations were used to investigate the effects of low-energy (5–50 eV) normally-incident self-ion irradiation of two-dimensional compact Pt3, Pt7, Pt19, and Pt37 clusters on Pt(111). We follow atomistic pathways leading to bombardment-induced intra- and interlayer mass transport. The results can be described in terms of three impact energy regimes. With E ≤ 20 eV, we observe an increase in 2D island dimensions and negligible residual point defect formation. As the impact energy is raised above 20 eV, we observe an increase in irradiation-induced lateral mass transport, a decrease in island size, and the activation of interlayer processes. For E ≥ 35 eV, this trend continues, but point defects, in the form of surface vacancies, are also formed. The results illustrate the richness of the dynamical interaction mechanisms occurring among incident energetic species, target clusters, and substrate atoms, leading to island preservation, reconfiguration, disruption and/or residual point defects formation. We discuss the significance of these results in terms of thin film growth.

  • 75.
    Adamovic, Dragan
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska högskolan.
    Münger, Peter
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska högskolan.
    Chirita, Valeriu
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Greene, Joe
    University of Illinois.
    Low-energy ion irradiation during film growth: Kinetic pathways leading to enhanced adatom migration rates2005Ingår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 86, s. 211915-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Embedded-atom molecular dynamics simulations are used to investigate the effects of low-energy self-ion irradiation of Pt adatoms on Pt(111). Here, we concentrate on self-bombardment dynamics, i.e., isolating and monitoring the atomic processes, induced by normally incident Pt atoms with energies E ranging from 5 to 50 eV, that can affect intra- and interlayer mass transport.. We find that adatom scattering, surface channeling, and dimer formation occur at all energies. Atomic intermixing events involving incident and terrace atoms are observed at energies 15  eV, while the collateral formation of residual surface vacancies is observed only with E>40  eV. The overall effect of low-energy self-ion irradiation is to enhance lateral adatom and terrace atom migration. ©2005 American Institute of Physics

  • 76.
    Adams, David A.
    et al.
    Department of Biology, Middle Tennessee State University, USA.
    Walck, Jeffery L.
    Department of Biology, Middle Tennessee State University, USA.
    Howard, R. Stephen
    Department of Biology, Middle Tennessee State University, USA.
    Milberg, Per
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ekologi. Linköpings universitet, Tekniska högskolan.
    Forest Composition and Structure onGlade-forming Limestones in Middle Tennessee2012Ingår i: Castanea, ISSN 0008-7475, Vol. 77, nr 4, s. 335-347Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Within a successional context, the vegetation associated with the cedar gladeecosystem in middle Tennessee develops from bare limestone bedrock to subclimax redcedar,preclimax oak-hickory, and climax mixed hardwood forests. Studies on the composition andstructure of forests associated with cedar glade–forming limestones (Lebanon, Ridley) are rare.We sampled the canopy and understory of six forest stands in middle Tennessee on theselimestones. Observed number of canopy species was 14–24 across stands; estimated richnesswas greater by 1–3 species (bootstrap) or 3–6 species (first-order jackknife) than observedrichness. With the exception of Ailanthus altissima in one stand, all other canopy species werenative. Juniperus virginiana, Fraxinus americana, Carya ovata, and Quercus muehlenbergii wereprimary canopy components in 4 or 6 stands, and C. glabra, Q. shumardii, Ulmus alata, F.quadrangulata, Q. alba, and Q. velutina in 2–3 stands. When we included stands from apreviously published study (most on the non-glade Carters Limestone) with our data, aprincipal components analysis identified three groups with the axes approximating a moisturebedrockgradient and a time-successional gradient. An examination of regeneration in ourstands predicts that (1) mesophytes and/or fire-sensitive species (Acer saccharum, Fraxinus spp.,Celtis spp.) will increase and (2) xerophytes and/or fire-adapted species (Quercus spp., Caryaspp.) will decrease. Altogether, our results strongly suggest that the oak-hickory stage shown insuccessional outlines of vegetation development associated with the cedar glade ecosystem maynot occur in its current state in the future.

  • 77.
    Admassie, S.
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Inganäs, Olle
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Electrochromism in diffractive conducting polymer gratings2004Ingår i: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 151, nr 6Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The electrochromic polymer poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate) (PEDOT-PSS) spin-coated on ITO/glass was patterned with a soft lithographic method in order to diffract the incident light and thereby modify absorption of light by the film to improve the electrochromic efficiency of the polymer. The absorbance peak at around 610 nm was found to be much higher in the patterned PEDOT-PSS film than the one observed in the unpatterned film. Values of coloration efficiencies varying from 107 to 174 cm2/C were obtained for three different unpatterned PEDOT-PSS films, whereas for three different patterned PEDOT-PSS films higher values ranging from 211 to 371 cm2/C were found. These increased values of the electrochromic efficiencies are attributed to diffraction. © 2004 The Electrochemical Society. All rights reserved.

  • 78.
    Admassie, Shimelis
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten. University of Addis Ababa, Ethiopia.
    Ajjan, Fátima
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Elfwing, Anders
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Inganäs, Olle
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Biopolymer hybrid electrodes for scalable electricity storage2016Ingår i: Materials Horizons, ISSN 2051-6347, E-ISSN 2051-6355, Vol. 3, nr 3, s. 174-185Artikel, forskningsöversikt (Refereegranskat)
    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.

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    fulltext
  • 79.
    Admassie, Shimelis
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Elfwing, Anders
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Jager, Edwin
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biosensorer och bioelektronik. Linköpings universitet, Tekniska högskolan.
    Bao, Qinye
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ytors Fysik och Kemi. Linköpings universitet, Tekniska högskolan.
    Inganäs, Olle
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    A renewable biopolymer cathode with multivalent metal ions for enhanced charge storage2014Ingår i: JOURNAL OF MATERIALS CHEMISTRY A, ISSN 2050-7488, Vol. 2, nr 6, s. 1974-1979Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A ternary composite supercapacitor electrode consisting of phosphomolybdic acid (HMA), a renewable biopolymer, lignin, and polypyrrole was synthesized by a simple one-step simultaneous electrochemical deposition and characterized by electrochemical methods. It was found that the addition of HMA increased the specific capacitance of the polypyrrole-lignin composite from 477 to 682 F g(-1) ( at a discharge current of 1 A g(-1)) and also significantly improved the charge storage capacity from 6(to 128 mA h g(-1).

  • 80.
    Admassie, Shimelis
    et al.
    Addis Ababa University.
    Inganäs, Olle
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik.
    Mammo, Wendimagegn
    Chalmers university of Technology.
    Perzon, Erik
    Chalmers university of Technology.
    Andersson, Mats R
    Chalmers university of Technology.
    Electrochemical and optical studies of the band gaps of alternating polyfluorene copolymers2006Ingår i: Synthetic metals, ISSN 0379-6779, E-ISSN 1879-3290, Vol. 156, nr 7-8, s. 614-623Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The electrochemical and optical properties of a series of alternating polyfluorene copolymers with low band gaps were determined. These polymers incorporated fluorene units alternating with groups including electron-withdrawing (A) and electron-donating (D) groups in donor-acceptor-donor (DAD) sequence to achieve the lowering of band gaps. The polymers were solvent-casted on platinum disk electrode and the band gaps were estimated from cyclic voltammetry (CV). These values were compared with values obtained from optical absorption measurements. Although the electrochemically determined band gaps were found to be slightly higher than the optical band gap in most cases, values are well correlated. The values of the band gaps determined range from 2.1 to 1.3 eV. © 2006 Elsevier B.V. All rights reserved.

  • 81. Admassie, Shimelis
    et al.
    Yacob, Zekarias
    Zhang, Fengling
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik.
    Mammo, Wendimagegn
    Yohannes, Teketel
    Solomon, Theodros
    Synthesis, optical and electrochemical characterization of anthrancene and benzothiadiazole-containing polyfluorene copolymers2006Ingår i: Bulletin of the Chemical Society of Ethiopia, ISSN 1011-3924, E-ISSN 1726-801X, Vol. 20, nr 2, s. 309-317Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    New solution-processable, anthrancene- and benzothiadiazole-containing polyfluorene copolymers (P1-P3) have been synthesized and characterized. The preparation and characterization of the corresponding blue light-emitting devices are also reported. Polymers P2 and P3 show high photoluminescence efficiency while polymer P2 does not show any significant light emission up to 8.0 V. The results show the need for balance of electron and hole transport in polymer light emitting diodes.

  • 82.
    Admassie, Shimelis
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Yang Nilsson, Ting
    University of Addis Ababa, Ethiopia.
    Inganas, Olle
    University of Addis Ababa, Ethiopia.
    Charge storage properties of biopolymer electrodes with (sub)tropical lignins2014Ingår i: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 16, nr 45, s. 24681-24684Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The electrochemical and charge storage properties of different lignins inside biopolymer electrodes were studied and correlated with the chemical variations of the lignins as indicated from the nuclear magnetic resonance (NMR) spectroscopic data. The varying fractions of monolignols were found to correlate with charge storage properties. It was found that as the sinapyl to guaiacyl (S/G) ratio increased both the specific capacitance and charge capacity increased considerably. This indicates that quinones generated on S-units can contribute more to charge storage in the biopolymer electrodes.

  • 83.
    Admassie, Shimelis
    et al.
    IFM Linköpings universitet.
    Zhang, Fengling
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik.
    Manoj, A.G.
    IFM Linköpings universitet.
    Svensson, Mattias
    Chalmers university of Technology.
    Andersson, Mats R
    Chalmers university of Technology.
    Inganäs, Olle
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik.
    A polymer photodiode using vapour-phase polymerized PEDOT as an anode2005Ingår i: Solar Energy Materials and Solar Cells, ISSN 0927-0248, E-ISSN 1879-3398, Vol. 90, s. 133-141Artikel i tidskrift (Refereegranskat)
    Abstract [en]

      

  • 84.
    Adnane, Bouchaib
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Yt- och Halvledarfysik. Linköpings universitet, Tekniska högskolan.
    Optical characterization of Silicon-based self-assembled nanostructures2010Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    This PhD thesis summarizes the work carried on the optical characterizations of some Si-based self-assembled nanostructures, particularly SiGe/Si quantum dots (QDs) and nanocrystalline (nc)-Si embedded in mesoporous silica (MS) using photoconductivity (PC), photoluminescence (PL), and photoluminescence excitation (PLE) measurements.

    The spectroscopic studies of SiGe/Si QDs grown on Si by molecular beam epitaxy revealed for the first time well-resolved PLE resonances. When correlated with numerical analysis, these resonances were directly related to the co-existence of spatially direct (inside the SiGe dot) and indirect (across the Si/Ge interface) recombination processes involving different dot populations selected by the monitored detection energy for PLE acquisition. The characteristics of these two transitions were further studied in detail by PLE (in some case implemented together with selective PL) on various samples, which contained either only one Ge dot layer or multiple Gedot/Si stacks, grown at substrate temperatures ranging from 430 to 580 °C; especially the temperature- and excitation power-dependence of the excitation properties. The results illustrated that the electronic structure of SiGe dots are influenced by size, Ge composition, as well as strain connected, and sometimes a mixed effect.

    Another attempt of the project was the fabrication of lateral transport mid-infrared photodetectors based on multiple Ge-dot/Si stacked structures. A broadband photoresponsivity of the processed multi-finger detectors was estimated to be about 90 mA/W over 3-15 μm range at 20 K, and the peaked photoresponse was measured at ~10 μm. The origin of the measured photocurrent, as elucidated by photoluminescence and photoluminescence excitation spectroscopies, was related to intersubband absorption of normal incidence infrared radiation corresponding to energies between the ground states of the heavy hole and the light hole in the valence band of the SiGe/Si QDs, and subsequent charge transfer to the Ge 2D wetting layer acting as a conduction channel. The absence of photocurrent in the energy range expected for a transition from the ground state to the first excited state of the heavy hole indicated that the holes in the SiGe dots behave essentially as 2D in character rather than a truly 3D confinement, where the transitions between heavy holes states are not allowed for TE polarized radiation (normal incidence).

    Finally, Si(or Ge) nanocrystals embedded in mesoporous silica samples prepared by spincoating and atomic layer chemical vapor deposition were optically investigated by means of PL with various excitation powers, together with several attempts using different post rapid thermal annealing processes. The shape and energy position of the PL spectra of the nc-Si embedded in MS samples and a reference MS template without nc incorporation were rather similar, but the luminescence was much more intense for those embedded with nanocrystals. This implies that the emission mechanism for MS samples with or without nc-Si could be the same, i.e., the light emission was governed by the surface properties of silica. The semiconductor nanocrystals played a role by sensitizing the luminescence emission through generating more photo-excited carriers. These carriers were then trapped in the defect state e.g. the interfacial oxygen defect sites and subsequently recombine to increase the PL intensity.

    Delarbeten
    1. Mid/far-infrared detection using a MESFET with B-modulation doped Ge-dot/SiGe-well multiple stacks in the channel region
    Öppna denna publikation i ny flik eller fönster >>Mid/far-infrared detection using a MESFET with B-modulation doped Ge-dot/SiGe-well multiple stacks in the channel region
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    2004 (Engelska)Konferensbidrag, Publicerat paper (Refereegranskat)
    Abstract [en]

    Multiple modulation-doped Ge-dot/SiGe-QW stack structures were grown using MBE, and processed as FET devices for mid/far infrared detection. From a non-optimized device, a broadband photoresponse has been observed in the mid-infrared range of 3-15 μm. A peak responsivity was estimated to be as high as 100 mA/W at T= 20 K. This work indicates that SiGE QD/QW structures using the lateral transport geometry can be a potential candidate for photodetectors operating in far-infrared range.

    Ort, förlag, år, upplaga, sidor
    IEEE, 2004
    Nationell ämneskategori
    Naturvetenskap
    Identifikatorer
    urn:nbn:se:liu:diva-53202 (URN)10.1109/GROUP4.2004.1416702 (DOI)0-7803-8474-1 (ISBN)
    Konferens
    First IEEE International Conference on Group IV Photonics
    Tillgänglig från: 2010-01-19 Skapad: 2010-01-19 Senast uppdaterad: 2010-04-28
    2. Origin of photoresponse at 8-14 μm in stacks of self-assembled SiGe/Si quantum dots
    Öppna denna publikation i ny flik eller fönster >>Origin of photoresponse at 8-14 μm in stacks of self-assembled SiGe/Si quantum dots
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    2009 (Engelska)Ingår i: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235XArtikel i tidskrift (Övrigt vetenskapligt) Submitted
    Abstract [en]

    A normal incidence photodetector operating at 8-14 μm is demonstrated using p-type δ-doped SiGe dot multilayer structures grown by molecular beam epitaxy on Si(001) substrates. Based on the experimental results of photoluminescence and photoluminescence excitation spectroscopies together with numerical analysis, the origin of the measured photocurrent was attributed to intersubband optical transitions between the heavy hole and light hole states of the valence band of the self-assembled SiGe dots and subsequent lateral transport of photo-excited carriers in the conduction channels formed by Ge wetting layers.

    Nationell ämneskategori
    Naturvetenskap
    Identifikatorer
    urn:nbn:se:liu:diva-53203 (URN)
    Tillgänglig från: 2010-01-19 Skapad: 2010-01-19 Senast uppdaterad: 2017-12-12
    3. Spatially direct and indirect transitions of self-assembled SiGe/Si quantum dots studied by photoluminescence excitation spectroscopy
    Öppna denna publikation i ny flik eller fönster >>Spatially direct and indirect transitions of self-assembled SiGe/Si quantum dots studied by photoluminescence excitation spectroscopy
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    2010 (Engelska)Ingår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 96, nr 18, s. 181107-Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Well-resolved photoluminescence excitation (PLE) spectra are reported for selfassembled SiGe dots grown on Si(100) by molecular beam epitaxy. The observation of two excitation resonance peaks is attributed to two different excitation/de-excitation routes of interband optical transitions connected to the spatially direct and indirect recombination processes. It is concluded that two dot populations are addressed by each monitored luminescence energy for the PLE acquisition.

    Nyckelord
    Ge-Si alloys, luminescence, molecular beam epitaxial growth, self-assembly, semiconductor quantum dots
    Nationell ämneskategori
    Naturvetenskap
    Identifikatorer
    urn:nbn:se:liu:diva-53204 (URN)10.1063/1.3424789 (DOI)000277422000007 ()
    Anmärkning
    Original Publication: Bouchaib Adnane, Fredrik Karlsson, Göran Hansson, Per-Olof Holtz and Wei-Xin Ni, Spatially direct and indirect transitions of self-assembled SiGe/Si quantum dots studied by photoluminescence excitation spectroscopy, 2010, Applied Physics Letters, (96), 18, 181107. http://dx.doi.org/10.1063/1.3424789 Copyright: American Institute of Physics http://www.aip.org/ Tillgänglig från: 2010-01-19 Skapad: 2010-01-19 Senast uppdaterad: 2017-12-12
    4. Photoluminescence excitation spectroscopy of self-assembled SiGe/Si quantum dots
    Öppna denna publikation i ny flik eller fönster >>Photoluminescence excitation spectroscopy of self-assembled SiGe/Si quantum dots
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    2009 (Engelska)Manuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    Photoluminescence excitation (PLE) experiments are reported for various self-assembled SiGe/Si dot samples grown on Si(001) by molecular beam epitaxy at substrate temperatures ranging from 430 to 580 C. Two excitation peaks were observed, and the characteristics of the involved optical transitions were studied in detail by PLE (in one case implemented together with selective photoluminescence, SPL) on different samples containing either only one SiGe dot layer or multiple SiGe-dot/Si stacks. The temperature- and power-dependence of the excitation properties together with the results of six-band k.p calculations support the assignment of the observed PLE peaks to spatially direct and indirect transitions collected from two different SiGe dot populations.

    Nationell ämneskategori
    Naturvetenskap
    Identifikatorer
    urn:nbn:se:liu:diva-53205 (URN)
    Tillgänglig från: 2010-01-19 Skapad: 2010-01-19 Senast uppdaterad: 2015-01-23
    5. Photoluminescence study of nanocrystalline-Si(Ge) embedded in mesoporous silica
    Öppna denna publikation i ny flik eller fönster >>Photoluminescence study of nanocrystalline-Si(Ge) embedded in mesoporous silica
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    2009 (Engelska)Ingår i: Solid-State Electronics, ISSN 0038-1101, E-ISSN 1879-2405, Vol. 53, nr 8, s. 862-864Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Photoluminescence (PL) properties of mesoporous silica (MS) samples incorporated with Si or Ge nanocrystals (nc) have been investigated with various excitation powers and post-RTA processes. The analysis of experimental results revealed a superlinear intensity dependence (m = 1.7) in the MS reference sample without nanocrystals, while a sublinear behavior (m = 0.8) is observed for the nc-Si in MS. It thus suggests the same recombination responsible for the luminescence at similar to 2.75 eV for both samples, but different kinetic limitations for the carrier transfer processes. Si nanocrystals play in this case an important role in generating more photo-excited carriers, enhancing the PL intensity.

    Nyckelord
    Mesoporous silica, Nanocrystals, Photoluminescence, Power dependence, Thermal annealing
    Nationell ämneskategori
    Naturvetenskap
    Identifikatorer
    urn:nbn:se:liu:diva-19884 (URN)10.1016/j.sse.2009.04.014 (DOI)
    Anmärkning
    Original Publication: Bouchaib Adnane, Yi-Fan Lai, Jia-Min Shieh, Per-Olof Holtz and Wei-Xin Ni, Photoluminescence study of nanocrystalline-Si(Ge) embedded in mesoporous silica, 2009, SOLID-STATE ELECTRONICS, (53), 8, 862-864. http://dx.doi.org/10.1016/j.sse.2009.04.014 Copyright: Elsevier Science B.V., Amsterdam. http://www.elsevier.com/ Tillgänglig från: 2009-08-14 Skapad: 2009-08-14 Senast uppdaterad: 2017-12-13
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    COVER01
  • 85.
    Adnane, Bouchaib
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Yt- och Halvledarfysik. Linköpings universitet, Tekniska högskolan.
    Elfving, Anders
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Yt- och Halvledarfysik. Linköpings universitet, Tekniska högskolan.
    Zhao, Ming
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Yt- och Halvledarfysik. Linköpings universitet, Tekniska högskolan.
    Larsson, Mats
    Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska högskolan.
    Magnuson, Bengt
    Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska högskolan.
    Ni, Wei-Xin
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Yt- och Halvledarfysik. Linköpings universitet, Tekniska högskolan.
    Mid/far-infrared detection using a MESFET with B-modulation doped Ge-dot/SiGe-well multiple stacks in the channel region2004Konferensbidrag (Refereegranskat)
    Abstract [en]

    Multiple modulation-doped Ge-dot/SiGe-QW stack structures were grown using MBE, and processed as FET devices for mid/far infrared detection. From a non-optimized device, a broadband photoresponse has been observed in the mid-infrared range of 3-15 μm. A peak responsivity was estimated to be as high as 100 mA/W at T= 20 K. This work indicates that SiGE QD/QW structures using the lateral transport geometry can be a potential candidate for photodetectors operating in far-infrared range.

  • 86.
    Adnane, Bouchaib
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Yt- och Halvledarfysik. Linköpings universitet, Tekniska högskolan.
    Karlsson, Fredrik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Hansson, Göran
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Yt- och Halvledarfysik. Linköpings universitet, Tekniska högskolan.
    Holtz, Per-Olof
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Ni, Wei-Xin
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Yt- och Halvledarfysik. Linköpings universitet, Tekniska högskolan.
    Photoluminescence excitation spectroscopy of self-assembled SiGe/Si quantum dots2009Manuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    Photoluminescence excitation (PLE) experiments are reported for various self-assembled SiGe/Si dot samples grown on Si(001) by molecular beam epitaxy at substrate temperatures ranging from 430 to 580 C. Two excitation peaks were observed, and the characteristics of the involved optical transitions were studied in detail by PLE (in one case implemented together with selective photoluminescence, SPL) on different samples containing either only one SiGe dot layer or multiple SiGe-dot/Si stacks. The temperature- and power-dependence of the excitation properties together with the results of six-band k.p calculations support the assignment of the observed PLE peaks to spatially direct and indirect transitions collected from two different SiGe dot populations.

  • 87.
    Adnane, Bouchaib
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Yt- och Halvledarfysik. Linköpings universitet, Tekniska högskolan.
    Karlsson, Fredrik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Hansson, Göran
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Yt- och Halvledarfysik. Linköpings universitet, Tekniska högskolan.
    Holtz, Per-Olof
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Ni, Wei-Xin
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Yt- och Halvledarfysik. Linköpings universitet, Tekniska högskolan.
    Spatially direct and indirect transitions of self-assembled SiGe/Si quantum dots studied by photoluminescence excitation spectroscopy2010Ingår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 96, nr 18, s. 181107-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Well-resolved photoluminescence excitation (PLE) spectra are reported for selfassembled SiGe dots grown on Si(100) by molecular beam epitaxy. The observation of two excitation resonance peaks is attributed to two different excitation/de-excitation routes of interband optical transitions connected to the spatially direct and indirect recombination processes. It is concluded that two dot populations are addressed by each monitored luminescence energy for the PLE acquisition.

    Ladda ner fulltext (pdf)
    FULLTEXT01
  • 88.
    Adnane, Bouchaib
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Yt- och Halvledarfysik. Linköpings universitet, Tekniska högskolan.
    Karlsson, Fredrik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Zhao, Ming
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Yt- och Halvledarfysik. Linköpings universitet, Tekniska högskolan.
    Hansson, Göran
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Yt- och Halvledarfysik. Linköpings universitet, Tekniska högskolan.
    Holtz, Per-Olof
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Ni, Wei-Xin
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Yt- och Halvledarfysik. Linköpings universitet, Tekniska högskolan.
    Origin of photoresponse at 8-14 μm in stacks of self-assembled SiGe/Si quantum dots2009Ingår i: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235XArtikel i tidskrift (Övrigt vetenskapligt)
    Abstract [en]

    A normal incidence photodetector operating at 8-14 μm is demonstrated using p-type δ-doped SiGe dot multilayer structures grown by molecular beam epitaxy on Si(001) substrates. Based on the experimental results of photoluminescence and photoluminescence excitation spectroscopies together with numerical analysis, the origin of the measured photocurrent was attributed to intersubband optical transitions between the heavy hole and light hole states of the valence band of the self-assembled SiGe dots and subsequent lateral transport of photo-excited carriers in the conduction channels formed by Ge wetting layers.

  • 89.
    Adnane, Bouchaib
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Yt- och Halvledarfysik. Linköpings universitet, Tekniska högskolan.
    Lai, Yi-Fan
    National Nano Device Labs, Taiwan.
    Shieh, Jia-Min
    National Nano Device Labs, Taiwan.
    Holtz, Per-Olof
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Ni, Wei-Xin
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Yt- och Halvledarfysik. Linköpings universitet, Tekniska högskolan.
    Photoluminescence study of nanocrystalline-Si(Ge) embedded in mesoporous silica2009Ingår i: Solid-State Electronics, ISSN 0038-1101, E-ISSN 1879-2405, Vol. 53, nr 8, s. 862-864Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Photoluminescence (PL) properties of mesoporous silica (MS) samples incorporated with Si or Ge nanocrystals (nc) have been investigated with various excitation powers and post-RTA processes. The analysis of experimental results revealed a superlinear intensity dependence (m = 1.7) in the MS reference sample without nanocrystals, while a sublinear behavior (m = 0.8) is observed for the nc-Si in MS. It thus suggests the same recombination responsible for the luminescence at similar to 2.75 eV for both samples, but different kinetic limitations for the carrier transfer processes. Si nanocrystals play in this case an important role in generating more photo-excited carriers, enhancing the PL intensity.

    Ladda ner fulltext (pdf)
    FULLTEXT01
  • 90. af Forselles, J.
    et al.
    von Eckardstein, S.
    Stegeryd, Y.
    Svanström, M.
    Ansell, Ricky
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär genetik. Linköpings universitet, Tekniska högskolan.
    Integration of rape case related information in the electronic communication between the Swedish police and the forensic laboratory2009Ingår i: Book of Abstracts, 2009, s. 126-Konferensbidrag (Refereegranskat)
  • 91.
    Afghahi, Morteza
    Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska högskolan.
    Clocking of high speed CMOS VLSI systems1991Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Two consequences of high level circuit integration may be increasing cost of design and cost of interconnections. Interconnection is expensive in terms of silicon area, speed and power. As far as timing is concerned. schemes of future VLSI systems may not be a simple extension of those used in the existing LSI circuits. This is because the relative importance of clock skew increases as the MOS technology develops and interconnections become slower and slower. Clock skew makes the design of VLSI synchronous circuits ineffective, complicated and failure prone. For a synchronous scheme to be useful in the VLSI environment and enjoy the experiences gained by designers, it must develop to a fast, simple, structured and robust scheme.

    To alleviate the adverse effects of clock skew, technological as well as circuit techniques may be employed. We have proposed a technological solution. It is suggested that a special interconnection metal layer should be introduced into the VLSI process and used for long interconnections. It is shown that by using this technique, the interconnection delay will not be a limiting factor for the performance of synchronous systems.

    We have also considered circuit solutions. To this end, physical causes of clock skew are investigated. It is shown that even for optimized interconnections, traditional modes of clocking results in unacceptable time performance for high speed synchronous systems. Then a new mode of clocking is presented and analysed in detail. By using this mode of clocking, the performance of synchronous systems scales with scaling the minimum feature size of MOS transistors.

    We have developed a synchronous scheme that is structured, simple and general. These factors also make the CMOS systems well suited for design compilation. A circuit technique is proposed that makes the design of synchronous schemes robust. Performance of different asynchronous schemes in VLSI environment is also investigated. It is shown that synchronous schemes outperforms standard asynchronous schemes for a wide range of important applications.

    Finally, in order to test some of the developed rules and principles, a chip has been designed as an example. In this design, a new hardware algorithm is presented for sorting. This algorithm is based on bit-serial data processing. It is shown that this design can operate at a clock frequency determined by the computational module delays and not by the clock skew.

  • 92.
    Afzal, Adeel
    et al.
    University of Bari Aldo Moro, Italy; King Fahd University of Petr and Minerals, Saudi Arabia; University of Hafr Al Batin, Saudi Arabia.
    Andersson, Mike
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad sensorvetenskap. Linköpings universitet, Tekniska fakulteten.
    Di Franco, Cinzia
    CNR IFN UOS Bari, Italy.
    Ditaranto, Nicoletta
    University of Bari Aldo Moro, Italy.
    Cioffi, Nicola
    University of Bari Aldo Moro, Italy; University of Bari Aldo Moro, Italy.
    Scamarcio, Gaetano
    CNR IFN UOS Bari, Italy; University of Bari Aldo Moro, Italy.
    Lloyd Spetz, Anita
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad sensorvetenskap. Linköpings universitet, Tekniska fakulteten. University of Oulu, Finland.
    Torsi, Luisa
    University of Bari Aldo Moro, Italy; University of Bari Aldo Moro, Italy.
    Electrochemical deposition of gold on indium zirconate (InZrOx with In/Zr atomic ratio 1.0) for high temperature automobile exhaust gas sensors2015Ingår i: Journal of Solid State Electrochemistry, ISSN 1432-8488, E-ISSN 1433-0768, Vol. 19, nr 9, s. 2859-2868Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Automobile exhaust gas emissions are causing serious damage to urban air quality in and around major cities of the world, which demands continuous monitoring of exhaust emissions. The chief components of automobile exhaust include carbon monoxide (CO), nitrogen oxides (NOx), and hydrocarbons. Indium zirconate (InZrOx) and gold/indium zirconate (Au/InZrOx) composite nanopowders are believed to be interesting materials to detect these substances. To this end, characterization and gas sensing properties of InZrOx and Au/InZrOx composite nanopowders are discussed. InZrOx nanoparticles with In/Zr atomic ratio of 1.00 (+/- 0.05) are synthesized via pH-controlled co-precipitation of In and Zr salts in aqueous ammonia. Gold (Au) nanoparticles are subsequently deposited on InZrOx using an in situ sacrificial Au electrolysis procedure. The products are characterized by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The gas sensing performance of Au/InZrOx composite nanopowder is studied by depositing a thick powder film on interdigitated electrode structures patterned on SiC substrate to facilitate high temperature operation. The resistivity of the Au/InZrOx layer is the sensor signal, and the sensors could be operated at 500-600 A degrees C, which is a suitable temperature range for engine exhaust measurements. The control sensing measurements reveal that Au/InZrOx composite nanopowder exhibits higher response towards 2-20 % O-2 gas as compared to pristine InZrOx nanoparticles. Further studies show that when applied to exhaust gases such as CO and nitric oxide (NO), the response of Au/InZrOx sensors is significantly higher towards NO in this temperature range. Thus, sensor performance characteristics of Au/InZrOx composite nanopowder are promising in terms of their applications in automobile exhaust emission control.

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    fulltext
  • 93.
    Agekyan, V F
    et al.
    n/a.
    Holtz, P O
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Materiefysik. Linköpings universitet, Tekniska högskolan.
    Karczewski, G
    n/a.
    Moskalenko, E S
    n/a.
    Yu, A
    n/a.
    Serov, x
    n/a.
    Filosofov, N G
    n/a.
    Exciton localization and sp-d energy transfer in CdMnTe/CdMgTe nanostructures with ultrathin narrow-gap magnetic layers2009Ingår i: 17th Int. Symp. “Nanostructures: Physics and Technology”, 2009Konferensbidrag (Refereegranskat)
  • 94.
    Agekyan, V F
    et al.
    St Petersburg State University.
    Holtz, Per-Olof
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Karczewski, G
    Polish Acadamy of Science.
    Moskalenko, E S
    Russian Acadamy of Science.
    Yu Serov, A
    St Petersburg State University.
    Filosofov, N G
    St Petersburg State University.
    Effect of a magnetic field on energy transfer of band states to the Mn2+ 3d shell in the CdMgTe matrix with ultrathin CdMnTe layers2010Ingår i: PHYSICS OF THE SOLID STATE, ISSN 1063-7834, Vol. 52, nr 1, s. 27-31Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The effect of external magnetic fields on two radiative (band-to-band and on-site) recombination channels in II-VI dilute magnetic semiconductors and related nanostructures has been considered. The 3d on-site emission of manganese ions in CdMgTe matrices containing periodic inclusions of CdMnTe narrow-band-gap layers with thicknesses of 0.5, 1.5, and 3.0 monolayers has been investigated in magnetic fields of up to 6 T. It has been shown that, in a magnetic field, luminescence of manganese ions weakens because of the decrease in the rate of spin-dependent excitation transfer from band states to the Mn2+ 3d shell. The maximum suppression of 3d luminescence has been observed in the matrix with a CdMnTe layer 3.0 monolayers thick. This indicates that the main factor responsible for the energy transfer is the internal field near the CdMnTe layers, which determines the magnetic splitting and spin polarization of band states.

  • 95.
    Agekyan, V F
    et al.
    St Petersburg State University.
    Holtz, Per-Olof
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Karczewski, G
    Polish Academy of Science.
    N Katz, V
    St Petersburg State University.
    Moskalenko, E S
    Russian Academy of Science.
    Yu Serov, A
    St Petersburg State University.
    Filosofov, N G
    St Petersburg State University.
    Magnetoluminescence of CdTe/MnTe/CdMgTe heterostructures with ultrathin MnTe layers2011Ingår i: Semiconductors (Woodbury, N.Y.), ISSN 1063-7826, E-ISSN 1090-6479, Vol. 45, nr 10, s. 1301-1305Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    CdTe/MnTe/CdMgTe quantum-well structures with one or two monolayers of MnTe inserted at CdTe/CdMgTe interfaces were fabricated. The spectra of the excitonic luminescence from CdTe quantum wells and their variation with temperature indicate that introduction of ultrathin MnTe layers improves the interface quality. The effect of a magnetic field in the Faraday configuration on the spectral position of the exciton-emission peaks indicates that frustration of magnetic moments in one-monolayer MnTe insertions is weaker than in two-monolayer insertions. The effect of a magnetic field on the exciton localization can be explained in terms of the exciton wave-function shrinkage and obstruction of the photoexcited charge-carrier motion in the quantum well.

  • 96.
    Aghda, Soheil Karimi
    et al.
    Rhein Westfal TH Aachen, Germany.
    Bogdanovski, Dimitri
    Rhein Westfal TH Aachen, Germany.
    Lo, Lukas
    Sua, Heng Han
    Rhein Westfal TH Aachen, Germany.
    Patterer, Lena
    Rhein Westfal TH Aachen, Germany.
    Holzapfel, Damian M.
    Rhein Westfal TH Aachen, Germany.
    Le Febvrier, Arnaud
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Hans, Marcus
    Rhein Westfal TH Aachen, Germany.
    Primetzhofer, Daniel
    Uppsala Univ, Sweden.
    Schneider, Jochen M.
    Rhein Westfal TH Aachen, Germany.
    Valence electron concentration- and N vacancy-induced elasticity in cubic early transition metal nitrides2023Ingår i: Acta Materialia, ISSN 1359-6454, E-ISSN 1873-2453, Vol. 255, artikel-id 119078Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Motivated by frequently reported deviations from stoichiometry in cubic transition metal nitride (TMNx) thin films, the effect of N-vacancy concentration on the elastic properties of cubic TiNx, ZrNx, VNx, NbNx, and MoNx (0.72 & LE; x & LE; 1.00) is systematically studied by density functional theory (DFT) calculations. The predictions are validated experimentally for VNx (0.77 & LE; x & LE; 0.97). The DFT results indicate that the elastic behavior of the TMNx depends on both the N-vacancy concentration and the valence electron concentration (VEC) of the transition metal: While TiNx and ZrNx exhibit vacancy-induced reductions in elastic modulus, VNx and NbNx show an increase. These trends can be rationalized by considering vacancy-induced changes in elastic anisotropy and bonding. While introduction of N-vacancies in TiNx results in a significant reduction of elastic modulus along all directions and a lower average bond strength of Ti-N, the vacancy-induced reduction in [001] direction of VNx is overcompensated by the higher stiffness along [011] and [111] directions, resulting in a higher average bond strength of V-N. To validate the predicted vacancy-induced changes in elasticity experimentally, close-to-singlecrystal VNx (0.77 & LE; x & LE; 0.97) are grown on MgO(001) substrates. As the N-content is reduced, the relaxed lattice parameter a0, as probed by X-ray diffraction, decreases from 4.128 & ANGS; to 4.096 & ANGS;. This reduction in lattice parameter is accompanied by an anomalous 11% increase in elastic modulus, as determined by nanoindentation. As the experimental data agree with the predictions, the elasticity enhancement in VNx upon N-vacancy formation can be understood based on the concomitant changes in elastic anisotropy and bonding.

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  • 97.
    Agirre, Jon
    et al.
    Univ York, England.
    Atanasova, Mihaela
    Univ York, England.
    Bagdonas, Haroldas
    Univ York, England.
    Ballard, Charles B.
    Rutherford Appleton Lab, England; Rutherford Appleton Lab, England.
    Basle, Arnaud
    Newcastle Univ, England.
    Beilsten-Edmands, James
    Diamond Light Source, England.
    Borges, Rafael J.
    Univ Campinas UNICAMP, Brazil.
    Brown, David G.
    Lab Servier SAS Inst Rech, France.
    Burgos-Marmol, J. Javier
    Univ Liverpool, England.
    Berrisford, John M.
    European Mol Biol Lab, England.
    Bond, Paul S.
    Univ York, England.
    Caballero, Iracema
    CSIC, Spain.
    Catapano, Lucrezia
    MRC Lab Mol Biol, England; Kings Coll London, England.
    Chojnowski, Grzegorz
    European Mol Biol Lab, Germany.
    Cook, Atlanta G.
    Univ Edinburgh, Scotland.
    Cowtan, Kevin D.
    Univ York, England.
    Croll, Tristan I.
    Univ Cambridge, England; Altos Labs, England.
    Debreczeni, Judit E.
    AstraZeneca, England.
    Devenish, Nicholas E.
    Diamond Light Source, England.
    Dodson, Eleanor J.
    Univ York, England.
    Drevon, Tarik R.
    Rutherford Appleton Lab, England; Rutherford Appleton Lab, England.
    Emsley, Paul
    MRC Lab Mol Biol, England.
    Evans, Gwyndaf
    Diamond Light Source, England; Rosalind Franklin Inst, England.
    Evans, Phil R.
    MRC Lab Mol Biol, England.
    Fando, Maria
    Rutherford Appleton Lab, England; Rutherford Appleton Lab, England.
    Foadi, James
    Univ Bath, England.
    Fuentes-Montero, Luis
    Diamond Light Source, England.
    Garman, Elspeth F.
    Univ Oxford, England.
    Gerstel, Markus
    Diamond Light Source, England.
    Gildea, Richard J.
    Diamond Light Source, England.
    Hatti, Kaushik
    Univ Cambridge, England.
    Hekkelman, Maarten L.
    Netherlands Canc Inst, Netherlands; Netherlands Canc Inst, Netherlands.
    Heuser, Philipp
    DESY, Germany.
    Hoh, Soon Wen
    Univ York, England.
    Hough, Michael A.
    Diamond Light Source, England; Univ Essex, England.
    Jenkins, Huw T.
    Univ York, England.
    Jimenez, Elisabet
    CSIC, Spain.
    Joosten, Robbie P.
    Netherlands Canc Inst, Netherlands; Netherlands Canc Inst, Netherlands.
    Keegan, Ronan M.
    Rutherford Appleton Lab, England; Rutherford Appleton Lab, England; Univ Liverpool, England.
    Keep, Nicholas
    Birkbeck Coll, England.
    Krissinel, Eugene B.
    Rutherford Appleton Lab, England; Rutherford Appleton Lab, England.
    Kolenko, Petr
    Czech Tech Univ, Czech Republic; Czech Acad Sci, Czech Republic.
    Kovalevskiy, Oleg
    Rutherford Appleton Lab, England; Rutherford Appleton Lab, England.
    Lamzin, Victor S.
    European Mol Biol Lab, Germany.
    Lawson, David M.
    John Innes Ctr, England.
    Lebedev, Andrey A.
    Rutherford Appleton Lab, England; Rutherford Appleton Lab, England.
    Leslie, Andrew G. W.
    MRC Lab Mol Biol, England.
    Lohkamp, Bernhard
    Karolinska Inst, Sweden.
    Long, Fei
    MRC Lab Mol Biol, England.
    Maly, Martin
    Czech Tech Univ, Czech Republic; Czech Acad Sci, Czech Republic; Univ Southampton, England.
    McCoy, Airlie J.
    Univ Cambridge, England.
    McNicholas, Stuart J.
    Univ York, England.
    Medina, Ana
    CSIC, Spain.
    Millan, Claudia
    Univ Cambridge, England.
    Murray, James W.
    Imperial Coll London, England.
    Murshudov, Garib N.
    MRC Lab Mol Biol, England.
    Nicholls, Robert A.
    MRC Lab Mol Biol, England.
    Noble, Martin E. M.
    Newcastle Univ, England.
    Oeffner, Robert
    Univ Cambridge, England.
    Pannu, Navraj S.
    Leiden Univ, Netherlands.
    Parkhurst, James M.
    Diamond Light Source, England; Rosalind Franklin Inst, England.
    Pearce, Nicholas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Bioinformatik. Linköpings universitet, Tekniska fakulteten.
    Pereira, Joana
    Univ Basel, Switzerland; Univ Basel, Switzerland.
    Perrakis, Anastassis
    Netherlands Canc Inst, Netherlands; Netherlands Canc Inst, Netherlands.
    Powell, Harold R.
    Imperial Coll London, England.
    Read, Randy J.
    Univ Cambridge, England.
    Rigden, Daniel J.
    Univ Liverpool, England.
    Rochira, William
    Univ York, England.
    Sammito, Massimo
    Univ Cambridge, England; AstraZeneca, England.
    Rodriguez, Filomeno Sanchez
    Univ York, England; Diamond Light Source, England; Univ Liverpool, England.
    Sheldrick, George M.
    Georg August Univ Gottingen, Germany.
    Shelley, Kathryn L.
    Univ Washington, WA 98195 USA.
    Simkovic, Felix
    Univ Liverpool, England.
    Simpkin, Adam J.
    Lab Servier SAS Inst Rech, France.
    Skubak, Pavol
    Leiden Univ, Netherlands.
    Sobolev, Egor
    DESY, Germany.
    Steiner, Roberto A.
    European Mol Biol Lab, England; Univ Padua, Italy.
    Stevenson, Kyle
    Rutherford Appleton Lab, England.
    Tews, Ivo
    Univ Southampton, England.
    Thomas, Jens M. H.
    Univ Liverpool, England.
    Thorn, Andrea
    Univ Hamburg, Germany.
    Trivino Valls, Josep
    CSIC, Spain.
    Uski, Ville
    Rutherford Appleton Lab, England; Rutherford Appleton Lab, England.
    Uson, Isabel
    CSIC, Spain; ICREA, Spain.
    Vagin, Alexei
    Univ York, England.
    Velankar, Sameer
    European Mol Biol Lab, England.
    Vollmar, Melanie
    European Mol Biol Lab, England.
    Walden, Helen
    Univ Glasgow, Scotland.
    Waterman, David
    Rutherford Appleton Lab, England; Rutherford Appleton Lab, England.
    Wilson, Keith S.
    Univ York, England.
    Winn, Martyn D.
    Sci & Technol Facil Council, England.
    Winter, Graeme
    Diamond Light Source, England.
    Wojdyr, Marcin
    Global Phasing Ltd, England.
    Yamashita, Keitaro
    MRC Lab Mol Biol, England.
    The CCP4 suite: integrative software for macromolecular crystallography2023Ingår i: Acta Crystallographica Section D: Structural Biology , E-ISSN 2059-7983, Vol. 79, s. 449-461Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Collaborative Computational Project No. 4 (CCP4) is a UK-led international collective with a mission to develop, test, distribute and promote software for macromolecular crystallography. The CCP4 suite is a multiplatform collection of programs brought together by familiar execution routines, a set of common libraries and graphical interfaces. The CCP4 suite has experienced several considerable changes since its last reference article, involving new infrastructure, original programs and graphical interfaces. This article, which is intended as a general literature citation for the use of the CCP4 software suite in structure determination, will guide the reader through such transformations, offering a general overview of the new features and outlining future developments. As such, it aims to highlight the individual programs that comprise the suite and to provide the latest references to them for perusal by crystallographers around the world.

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  • 98. Beställ onlineKöp publikationen >>
    Agnvall, Beatrix
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biologi. Linköpings universitet, Tekniska fakulteten.
    Early domestication?: Phenotypic alterations of Red Junglefowl selected for divergent fear of humans2016Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [sv]

    Den här avhandlingen är ett resultat av ett projekt där vi avlat djur på tamhet för att undersöka egenskapens roll i den tidiga domesticeringen. De domesticerade djur som vi har i vår närhet har alla genomgått en process där de har anpassats för vår miljö. Det skulle kunna liknas vid en snabb evolution, där ett djurs utseende och beteende förändras under en relativt sett kort tid genom avel av människan. Domesticerade djur skiljer sig från sina vilda släktingar på många olika sätt, de kan vara både mindre och större är ursprunget, finnas i olika färgvariationer, ha ändrade kroppsproportioner och de skiljer sig även åt i tröskelvärden för beteende från de vilda djuren. Skillnaderna mellan domesticerade djur och ursprunget är förvånansvärt lika mellan djurarter och man brukar kalla detta för den domesticerade fenotypen.

    I det här projektet ville vi se om den domesticerade fenotypen egentligen är en biprodukt som uppkommer om man avlar djur på tamhet, på så sätt skulle rädslan för människor vara en nyckelegenskap för domesticeringen. För att undersöka detta använde vi det röda djungelhönset (RJF) som alla domesticerade höns härstammar ifrån. I sex generationer avlades RJF som antingen hade hög eller låg rädsla för människor. Eftersom vi bara har ett avelskriterium kan vi dra slutsatsen att om dessa djur kommer att skilja sig åt på fler sätt så beror det på korrelerade selektionseffekter. Det vill säga, man avlar på en egenskap och andra egenskaper följer med.

    I varje generation har vi utfört beteendetester på djuren som främst varit kopplade till rädsla, utforskande och sociala beteenden. Utöver beteendetesterna har vi undersökt djurens kroppsvikt, äggvikt, metabolism, födointag, fjäderdräkt och tagit blodprov för att mäta kortikosteron och serotonin. När djuren har avlivats har vi vägt hjärnan, hjärtat, levern, mjälten och testiklarna.

    Efter sex generationer av selekterad avel hade hönsen i projektet förändrats på olika sätt. Först och främst konstaterade vi att rädslan för människa är möjlig att avla på då den har en signifikant genetisk arvbarhet. De djuren som har en låg rädsla för människor har blivit större, socialt dominanta, lägger större ägg och får större avkomma. Metabolismen har påverkats så att de höns som har låg rädsla för människor har högre metabolism och omsätter även maten mer till tillväxt än de djuren med hög rädsla. Aveln har även påverkat djurens morfologi, de djuren som har hög rädsla för människor och alltså kan anses vara mer som ursprunget har större hjärna, hjärta, lever och mjälte. Många av dessa förändringar som uppkommit redan efter sex generationer korrelerar med de skillnader man ser mellan vilda och domesticerade djur vilket påvisar vikten av egenskapen för domesticeringsprocessen.

    Delarbeten
    1. Heritability and Genetic Correlations of Fear-Related Behaviour in Red Jungelfowl -Possible Implications for Early Domestication
    Öppna denna publikation i ny flik eller fönster >>Heritability and Genetic Correlations of Fear-Related Behaviour in Red Jungelfowl -Possible Implications for Early Domestication
    2012 (Engelska)Ingår i: PLOS ONE, E-ISSN 1932-6203, Vol. 7, nr 4, s. e35162-Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Domesticated species differ from their wild ancestors in a number of traits, generally referred to as the domesticated phenotype. Reduced fear of humans is assumed to have been an early prerequisite for the successful domestication of virtually all species. We hypothesized that fear of humans is linked to other domestication related traits. For three generations, we selected Red Junglefowl (ancestors of domestic chickens) solely on the reaction in a standardized Fear of Human-test. In this, the birds were exposed for a gradually approaching human, and their behaviour was continuously scored. This generated three groups of animals, high (H), low (L) and intermediate (I) fearful birds. The birds in each generation were additionally tested in a battery of behaviour tests, measuring aspects of fearfulness, exploration, and sociality. The results demonstrate that the variation in fear response of Red Junglefowl towards humans has a significant genetic component and is genetically correlated to behavioural responses in other contexts, of which some are associated with fearfulness and others with exploration. Hence, selection of Red Junglefowl on low fear for humans can be expected to lead to a correlated change of other behavioural traits over generations. It is therefore likely that domestication may have caused an initial suite of behavioural modifications, even without selection on anything besides tameness.

    Nationell ämneskategori
    Naturvetenskap
    Identifikatorer
    urn:nbn:se:liu:diva-76833 (URN)10.1371/journal.pone.0035162 (DOI)000305336200026 ()
    Tillgänglig från: 2012-04-20 Skapad: 2012-04-20 Senast uppdaterad: 2023-12-28
    2. Red Junglefowl (Gallus gallus) selected for low fear of humans are larger, more dominant and produce larger offspring
    Öppna denna publikation i ny flik eller fönster >>Red Junglefowl (Gallus gallus) selected for low fear of humans are larger, more dominant and produce larger offspring
    2014 (Engelska)Ingår i: animal, ISSN 1751-7311, Vol. 8, nr 9, s. 1498-1505Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Many traits associated with domestication are suggested to have developed as correlated responses to reduced fear of humans. Tameness may have reduced the stress of living in human proximity and improved welfare in captivity. We selected Red Junglefowl (ancestors of all domestic chickens) for four generations on high or low fear towards humans, mimicking an important aspect of the earliest period of domestication, and tested birds from the third and fourth generation in three different social tests. Growth and plumage condition, as well as size of eggs and offspring were also recorded, as indicators of some aspects of welfare. Birds selected for low fear had higher weight, laid larger eggs and generated larger offspring, and had a better plumage condition. In a social dominance test they also performed more aggressive behaviour and received less of the same, regardless of whether the restricted resource was feed or not. Hence, dominance appeared to increase as a consequence of reduced fear of humans. Furthermore, egg size and the weight of the offspring were larger in the less fearful birds, and plumage condition better, which could be interpreted as the less fearful animals being better adapted to the environment in which they were selected.

    Ort, förlag, år, upplaga, sidor
    Cambridge University Press, 2014
    Nyckelord
    Red Junglefowl, domestication, fearfulness, selection, social behaviour
    Nationell ämneskategori
    Biologiska vetenskaper
    Identifikatorer
    urn:nbn:se:liu:diva-109499 (URN)10.1017/S1751731114001426 (DOI)000342219000013 ()24910136 (PubMedID)
    Tillgänglig från: 2014-08-20 Skapad: 2014-08-20 Senast uppdaterad: 2023-12-28
    3. Is domestication driven by reduced fear of humans? Boldness, metabolism and serotonin levels in divergently selected red junglefowl (Gallus gallus)
    Öppna denna publikation i ny flik eller fönster >>Is domestication driven by reduced fear of humans? Boldness, metabolism and serotonin levels in divergently selected red junglefowl (Gallus gallus)
    2015 (Engelska)Ingår i: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 11, nr 9, artikel-id 20150509Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Domesticated animals tend to develop a coherent set of phenotypic traits. Tameness could be a central underlying factor driving this, and we therefore selected red junglefowl, ancestors of all domestic chickens, for high or low fear of humans during six generations. We measured basal metabolic rate (BMR), feed efficiency, boldness in a novel object (NO) test, corticosterone reactivity and basal serotonin levels (related to fearfulness) in birds from the fifth and sixth generation of the high- and low-fear lines, respectively (44-48 individuals). Corticosterone response to physical restraint did not differ between selection lines. However, BMR was higher in low-fear birds, as was feed efficiency. Low-fear males had higher plasma levels of serotonin and both low-fear males and females were bolder in an NO test. The results show that many aspects of the domesticated phenotype may have developed as correlated responses to reduced fear of humans, an essential trait for successful domestication.

    Ort, förlag, år, upplaga, sidor
    ROYAL SOC, 2015
    Nyckelord
    genetics; domestication; stress
    Nationell ämneskategori
    Zoologi Evolutionsbiologi
    Identifikatorer
    urn:nbn:se:liu:diva-123162 (URN)10.1098/rsbl.2015.0509 (DOI)000364772300009 ()26382075 (PubMedID)
    Anmärkning

    Funding Agencies|research council Formas; ERC [322206]

    Tillgänglig från: 2015-12-07 Skapad: 2015-12-04 Senast uppdaterad: 2023-12-28Bibliografiskt granskad
    4. Effects of Divergent Selection for Fear of Humans on Behaviour in Red Junglefowl
    Öppna denna publikation i ny flik eller fönster >>Effects of Divergent Selection for Fear of Humans on Behaviour in Red Junglefowl
    2016 (Engelska)Ingår i: PLOS ONE, E-ISSN 1932-6203, Vol. 11, nr 11, s. 1-12Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Domestication has caused a range of similar phenotypic changes across taxa, relating to physiology, morphology and behaviour. It has been suggested that this recurring domesticated phenotype may be a result of correlated responses to a central trait, namely increased tameness. We selected Red Junglefowl, the ancestors of domesticated chickens, during five generations for reduced fear of humans. This caused a marked and significant response in tameness, and previous studies have found correlated effects on growth, metabolism, reproduction, and some behaviour not directly selected for. Here, we report the results from a series of behavioural tests carried out on the initial parental generation (P0) and the fifth selected generation (S5), focusing on behaviour not functionally related to tameness, in order to study any correlated effects. Birds were tested for fear of humans, social reinstatement tendency, open field behaviour at two different ages, foraging/exploration, response to a simulated aerial predator attack and tonic immobility. In S5, there were no effects of selection on foraging/exploration or tonic immobility, while in the social reinstatement and open field tests there were significant interactions between selection and sex. In the aerial predator test, there were significant main effects of selection, indicating that fear of humans may represent a general wariness towards predators. In conclusion, we found only small correlated effects on behaviours not related to the tameness trait selected for, in spite of them showing high genetic correlations to fear of humans in a previous study on the same population. This suggests that species-specific behaviour is generally resilient to changes during domestication.

    Ort, förlag, år, upplaga, sidor
    PLOS, 2016
    Nationell ämneskategori
    Utvecklingsbiologi Genetik
    Identifikatorer
    urn:nbn:se:liu:diva-132742 (URN)10.1371/journal.pone.0166075 (DOI)000387909300035 ()27851792 (PubMedID)
    Anmärkning

    European Research Council [322206]; FORMAS [221-2007-838]; Vetenskapsradet [621-2008-5437]

    Tillgänglig från: 2016-11-22 Skapad: 2016-11-22 Senast uppdaterad: 2023-12-28Bibliografiskt granskad
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    Early domestication?: Phenotypic alterations of Red Junglefowl selected for divergent fear of humans
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  • 99.
    Agnvall, Beatrix
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biologi. Linköpings universitet, Tekniska högskolan.
    Ali, A.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biologi. Linköpings universitet, Tekniska högskolan.
    Olby, S.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biologi. Linköpings universitet, Tekniska högskolan.
    Jensen, Per
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biologi. Linköpings universitet, Tekniska högskolan.
    Red Junglefowl (Gallus gallus) selected for low fear of humans are larger, more dominant and produce larger offspring2014Ingår i: animal, ISSN 1751-7311, Vol. 8, nr 9, s. 1498-1505Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Many traits associated with domestication are suggested to have developed as correlated responses to reduced fear of humans. Tameness may have reduced the stress of living in human proximity and improved welfare in captivity. We selected Red Junglefowl (ancestors of all domestic chickens) for four generations on high or low fear towards humans, mimicking an important aspect of the earliest period of domestication, and tested birds from the third and fourth generation in three different social tests. Growth and plumage condition, as well as size of eggs and offspring were also recorded, as indicators of some aspects of welfare. Birds selected for low fear had higher weight, laid larger eggs and generated larger offspring, and had a better plumage condition. In a social dominance test they also performed more aggressive behaviour and received less of the same, regardless of whether the restricted resource was feed or not. Hence, dominance appeared to increase as a consequence of reduced fear of humans. Furthermore, egg size and the weight of the offspring were larger in the less fearful birds, and plumage condition better, which could be interpreted as the less fearful animals being better adapted to the environment in which they were selected.

    Ladda ner fulltext (pdf)
    fulltext
  • 100.
    Agnvall, Beatrix
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biologi. Linköpings universitet, Tekniska fakulteten.
    Bélteky, Johan
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biologi. Linköpings universitet, Tekniska fakulteten.
    Jensen, Per
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biologi. Linköpings universitet, Tekniska fakulteten.
    Brain size is reduced by selectionfor tameness in Red Junglefowl–correlated effects in vital organs2017Ingår i: Scientific Reports, E-ISSN 2045-2322, Vol. 7, artikel-id 3306Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    During domestication animals have undergone changes in size of brain and other vital organs. We hypothesize that this could be a correlated effect to increased tameness. Red Junglefowl (ancestors of domestic chickens) were selected for divergent levels of fear of humans for five generations. The parental (P0) and the fifth selected generation (S5) were culled when 48–54 weeks old and the brains were weighed before being divided into telencephalon, cerebellum, mid brain and optic lobes. Each single brain part as well as the liver, spleen, heart and testicles were also weighed. Brains of S5 birds with high fear scores (S5 high) were heavier both in absolute terms and when corrected for body weight. The relative weight of telencephalon (% of brain weight) was significantly higher in S5 high and relative weight of cerebellum was lower. Heart, liver, testes and spleen were all relatively heavier (% of body weight) in S5 high. Hence, selection for tameness has changed the size of the brain and other vital organs in this population and may have driven the domesticated phenotype as a correlated response.

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