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  • 251.
    Filippini, Daniel
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Suska, Anke
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Lundström, Ingemar
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Natural nanosystems2007In: International Symposium on Biomolecular Nanoscale Assemblies,2007, 2007Conference paper (Refereed)
  • 252.
    Filippini, Daniel
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Tejle, Katarina
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology.
    Lundström, Ingemar
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    ELISA test for anti-neutrophil cytoplasm antibodies detection evaluated by a computer screen photo-assisted technique2005In: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 21, no 2, p. 266-272Article in journal (Refereed)
    Abstract [en]

    The computer screen photo-assisted technique (CSPT), a method for substance classification based on spectral fingerprinting, which involves just a computer screen and a web camera as measuring platform is used here for the evaluation of a prospective enzyme-linked immunosorbent assay (ELISA). A anti-neutrophil cytoplasm antibodies (ANCA-ELISA) test, typically used for diagnosing patients suffering from chronic inflammatory disorders in the skin, joints, blood vessels and other tissues is comparatively tested with a standard microplate reader and CSPT, yielding equivalent results at a fraction of the instrumental costs. The CSPT approach is discussed as a distributed measuring platform allowing decentralized measurements in routine applications, whereas keeping centralized information management due to its natural network embedded operation. © 2004 Elsevier B.V. All rights reserved.

  • 253.
    Filippini, Daniel
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Winquist, Fredrik
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Lundström, Ingemar
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Computer screen photo-excited surface plasmon resonance imaging2008In: Analytica Chimica Acta, ISSN 0003-2670, E-ISSN 1873-4324, Vol. 625, no 2, p. 207-214Article in journal (Refereed)
    Abstract [en]

    Angle and spectra resolved surface plasmon resonance (SPR) images of gold and silver thin films with protein deposits is demonstrated using a regular computer screen as light source and a web camera as detector. The screen provides multiple-angle illumination, p-polarized light and controlled spectral radiances to excite surface plasmons in a Kretchmann configuration. A model of the SPR reflectances incorporating the particularities of the source and detector explain the observed signals and the generation of distinctive SPR landscapes is demonstrated. The sensitivity and resolution of the method, determined in air and solution, are 0.145 nm pixel-1, 0.523 nm, 5.13 × 10-3 RIU degree-1 and 6.014 × 10-4 RIU, respectively, encouraging results at this proof of concept stage and considering the ubiquity of the instrumentation. © 2008 Elsevier B.V. All rights reserved.

  • 254.
    Filippini, Daniel
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Åsberg, Peter
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Nilsson, Peter
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Lundström, Ingemar
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Computer screen photo-assisted spectral fingerprinting of luminescent polythiophene pH reporter2004In: IEEE Sensors. Proceedings, ISSN 1930-0395, E-ISSN 2168-9229, Vol. 3, p. 1377-1380Article in journal (Refereed)
    Abstract [en]

    The capability of the computer screen photo-assisted technique (CSPT)for the spectral fingerprinting of a photoactive polythiophene derivative (POWT) used as pH reporter is demonstrated. POWT is part of a family of industrial scalable materials, well established for organic electronics and biomedical applications, which is used here to demonstrate the capability of CSPT for tracing key spectral features. The ability of CSPTfor substance classification, corroborated by principal component analysis (PCA), successfully compares to standard spectroscopy, especially considering the involved equipments: CSPT is only a computer set and a web camera.

  • 255.
    Filippini, Daniel
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Åsberg, Peter
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics .
    Nilsson, Peter
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics .
    Inganäs, Olle
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics .
    Lundström, Ingemar
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Computer screen photo-asssited detection of complementary DNA strands using a luminescent zwitterionic polythiophene derivative2006In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 1132006, p. 410-418Article in journal (Refereed)
  • 256. Fogelberg, J.
    et al.
    Dannetun, Helen
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Lundström, Ingemar
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Petersson, L.-G.
    A hydrogen sensitive palladium metal-oxide-semiconductor device as sensor for dissociating NO in H2-atmospheres1990In: Vacuum, ISSN 0042-207X, E-ISSN 1879-2715, Vol. 41, p. 705-Article in journal (Refereed)
    Abstract [en]

    A Pd-MOS structure can be used as a sensitive analytical tool in the study of dissociating oxygen containing molecules. Nitric oxide has been studied as a test case. Initially NO adsorbs very effectively and dissociatively on polycrystalline Pd at temperatures above 473 K. At this temperature H2O, N2O and N2 desorbs during an NO exposure in a hydrogen background. After such exposure the surface is probably left with only residual nitrogen atoms adsorbed on the surface. Below 390 K the dissociation probability is insignificant.

  • 257.
    Fogelberg, J.
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Eriksson, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Dannetun, Helen
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Petersson, L.-G.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    H2-D2 exchange on an oxygen covered Pd-film: A study of the backreaction on a hydrogen sensitive MOS device1992Conference paper (Refereed)
  • 258. Fogelberg, J.
    et al.
    Eriksson, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Dannetun, Helen
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Petersson, L.-G.
    Kinetic modelling of hydrogen ad/absorption in thin films of hydrogen sensitive field effect devices: Observation of large hydrogen induced dipoles at the Pd/SiO2 interface1995In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, ISSN 0021-8979, Vol. 78, p. 988-Article in journal (Refereed)
    Abstract [en]

    A kinetic modeling of the hydrogen interaction with a Pd‐SiO2‐Si (Pd‐MOS) device is reported. The model is fitted to a number of experimental results, mainly from mass spectrometric desorption measurements. The new results verify an older description of the energetics of hydrogen adsorption states at the Pd/SiO2 interface in the sense that the adsorption may be described by a so‐called Temkin isotherm; however, several new findings have to be incorporated into the model in order to obtain a consistent picture. The initial heat of adsorption at the interface is around 0.8 eV/hydrogen atom. The number of adsorption sites at the interface is considerably smaller than at the surface, 6×1017 m−2 versus 1.5×1019 m−2. Furthermore, the interface hydrogen atoms are strongly polarized. An average value of 2 Debye is obtained. It is the large hydrogen polarization at the Pd/SiO2 interface and not a large concentration of adsorbed hydrogen atoms per se which accounts for the very high sensitivity of a Pd‐MOS device as hydrogen sensor

  • 259.
    Fornander, H.
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Dannetun, Helen
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics . Linköping University, The Institute of Technology.
    Ekedahl, L.-G.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    A comparison of the CO and D2 oxidation reactions on Pd supported on MgO(100), MgO(110) and MgO(111)1999In: Surface Science, ISSN 0039-6028, E-ISSN 1879-2758, Vol. 440, no 3, p. 375-386Article in journal (Refereed)
    Abstract [en]

    Oxidation of D2 and CO on oxygen pre-exposed 200 nm thick Pd films, epitaxially grown on MgO(100), MgO(110) and MgO(111), has been investigated in the temperature range 100–300°C. Oxygen initial sticking coefficients have been determined to be close to 1 for the 100 and 110 films, and around 0.8 for the 111 film. The sticking coefficient and reactive sticking coefficient for CO oxidation on Pd/MgO(100) is also close to 1, and the maximum reactive sticking coefficient for hydrogen oxidation is determined to be around 0.9 at temperatures above 200°C. It is shown that the reactivities for the different surfaces vary strongly with surface and oxygen coverage, and the consequence of this for supported particle catalysts is pointed out.

  • 260.
    Fornander, H.
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Ekedahl, L.-G.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Dannetun, Helen
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics . Linköping University, The Institute of Technology.
    Oxidation of carbon monoxide and deuterium on a Pd (100) film1999In: Catalysis Letters, ISSN 1011-372X, E-ISSN 1572-879X, Vol. 59, p. 107-113Article in journal (Refereed)
    Abstract [en]

    For Pd/MgO(100) pre-exposed to oxygen, the catalytic oxidation of CO and D2, respectively, has been studied in the temperature range 100–300 _C. At temperatures >200 _C, the CO2 desorption rate is independent of oxygen coverage, _O, and the reactive sticking coefficient for CO is close to unity. The D2O desorption rate is strongly dependent on _O. D2 adsorption is blocked by adsorbed oxygen and the maximum D2O desorption rate is reached when almost all oxygen has been consumed (_O < 0:03). The formation of an oxygen c(2 _ 2) structure, coexisting with the initial p(2 _ 2) phase, is reflected in the oxidation rates.

  • 261.
    Fornander, H.
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Ekedahl, L.-G.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Dannetun, Helen
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics . Linköping University, The Institute of Technology.
    Structural effects of supported Pd particles in D2 and CO oxidation experiments1999In: Surface Science, ISSN 0039-6028, E-ISSN 1879-2758, Vol. 441, no 2-3, p. 479-492Article in journal (Refereed)
    Abstract [en]

    In the temperature range 100–300°C, isothermic D2 and CO titration experiments have been performed on oxygen pre-exposed 1.5, 4, 20 and 200 nm thick Pd films, epitaxially cube-on-cube grown on MgO(100). The oxygen pre-exposures varied from 0.2 to 150 L. The three thinnest films consisted of faceted particles, mainly bounded by Pd(111) and Pd(100) surfaces, while the 200 nm sample was a continuous, flat Pd(100) film with atomic steps. Atomic force microscopy demonstrated that the titration experiment did not affect the structure of the (large) Pd particles in the 20 nm film. The reaction behavior of the 1.5 nm film can be understood by assuming that the film consists of (111)-bounded Pd particles, where O2 and D2 dissociate and spill over to the oxide support, whereas CO adsorbs and reacts both on the Pd and on the oxide. The CO oxidation thus occurs in parallel on Pd and on MgO, while the D2 oxidation is sequential, first occurring on the Pd and then on the MgO. To explain the D2O desorption curves for the 4 and 20 nm films, spillover to the MgO support as well as reactions on the Pd(111) and Pd(100) facets have to be taken into account. The greater the oxygen pre-exposure, the higher the probability that the D2 molecules dissociate primarily on the Pd(111) surfaces.

  • 262.
    Forsgren, Gunnar
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Winquist, Fredrik
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics . Linköping University, The Institute of Technology.
    Andersson, Thorbjörn
    Tetra Pak Packaging Solutions AB, Development & Engineering Material Innovation, Ruben Rausings gata, SE-221 86 Lund, Sweden.
    Flavour interactions in aqueous solutions of an aldehyde, a ketone and a carboxylic acid2009Article in journal (Other academic)
    Abstract [en]

    Flavour impressions of aqueous solutions of nonanoic acid, octan-2-one and octanal were investigated. In a pre-study, the psychophysical functions of single component solutions were estimated and good agreements to Fechner’s law were obtained. The findings guided the choice of concentrations used in the main flavour interaction study. In this study, binary mixture interactions of nonanoic acid – octanal and octan-2-one – octanal were investigated in terms of perceived intensity and quality. Ten assessors judged the mixture solutions for flavour intensity by applying a free magnitude estimation procedure and describing their perceived quality impressions. The five assessors who were able to describe the perceived qualities in a consistent and logic way considered both mixtures being heterogeneous. Only three assessors scored intensities of the included single component solutions well in agreement with Fechner’s law. These three assessors’ intensity scorings of the mixtures did not deviate from those of a hypothetic additive model in a clear way. The intensity scorings of most of the other assessors were strongly dominated by one of the two components whereas some assessor did not score systematic at all.

  • 263.
    Forsgren, Gunnar
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Winquist, Fredrik
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics . Linköping University, The Institute of Technology.
    Öström, Åsa
    Department of Restaurant and Culinary Arts, Örebro University, Sörälgsvägen 2, Grythyttan, Sweden.
    Analysis of volatile compounds of aqueous thyme solutions by headspace gas chromatography, gas sensor arrays ("electronic nose") and a sensory odour panel2010Article in journal (Other academic)
    Abstract [en]

    The ability of a commercial emission analysis system to evaluate a sensory related attribute was investigated. Since food applications are very complex, a simplified model system consisting of aqueous thyme solutions was evaluated. Sensory odour assessments were made as well as instrumental analysis applying the emission analyser, based on gas sensor arrays, (a so called electronic nose) and headspace gas chromatography. The operation of the emission analyser was found critical and could be optimised thanks to the detailed chemical information obtained by the chromatography. This information also guided a proper evaluation of the emission analyser raw data and predictions of the relative thyme concentrations of the solutions. In that way the emission analyser separated the thyme solutions even better than the assessors applying sensory odour analysis. Since the results seem encouraging the strategy developed and knowledge gained may well be used for investigating more complex systems closer to real applications.

  • 264.
    Francioso, L.
    et al.
    University Campus, Lecce, Italy.
    Bjorklund, Robert
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Krantz-Rülcker, Tina
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Siciliano, P.
    University Campus, Lecce, Italy.
    Classification of multiple defect concentrations in white wine by platinum microelectrode voltammetry2007In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 125, no 2, p. 462-467Article in journal (Refereed)
    Abstract [en]

    Concentrations of defect pairs added to a white wine were classified by voltammetric measurements on interdigitated platinum microelectrodes using principal component analysis of the current responses. Combinations of 0, 1, 2 and 3 mM concentrations were investigated. The defect pair ascorbic acid/acetaldehyde exhibited little interaction with each other and the pair-wise concentrations were symmetrically positioned in a score plot around a center axis of equimolar concentrations. The ascorbic acid/sulfur dioxide pair exhibited a center axis for the equimolar concentrations shifted toward the 3 mM sulfur dioxide sample. The defect pair having the strongest interaction through complex formation, acetaldehyde/sulfur dioxide, had the equimolar concentrations in score plots located near the white wine control sample. © 2007 Elsevier B.V. All rights reserved.

  • 265.
    Fröjd, Victoria
    et al.
    Department of Prosthodontics, Malmö University, Malmö, Sweden .
    Linderbäck, Paula
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Wennerberg, Ann
    Department of Prosthodontics, Malmo University, Malmo and Department of Biomaterials, Institute of Clinical Sciences, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden.
    de Paz, Luis Chavez
    Department of Oral Biology, Malmö University, Malmö, Sweden .
    Svensäter, Gunnel
    Department of Oral Biology, Malmö University, Malmö, Sweden.
    Davies, Julia R.
    Department of Oral Biology, Malmö University, Malmö, Sweden .
    Effect of nanoporous TiO2 coating and anodized Ca2+ modification of titanium surfaces on early microbial biofilm formation2011In: BMC Oral Health, ISSN 1472-6831, E-ISSN 1472-6831, Vol. 11, p. 8-Article in journal (Refereed)
    Abstract [en]

    Background: The soft tissue around dental implants forms a barrier between the oral environment and the peri-implant bone and a crucial factor for long-term success of therapy is development of a good abutment/soft-tissue seal. Sol-gel derived nanoporous TiO2 coatings have been shown to enhance soft-tissue attachment but their effect on adhesion and biofilm formation by oral bacteria is unknown. Methods: We have investigated how the properties of surfaces that may be used on abutments: turned titanium, sol-gel nanoporous TiO2 coated surfaces and anodized Ca2+ modified surfaces, affect biofilm formation by two early colonizers of the oral cavity: Streptococcus sanguinis and Actinomyces naeslundii. The bacteria were detected using 16S rRNA fluorescence in situ hybridization together with confocal laser scanning microscopy. Results: Interferometry and atomic force microscopy revealed all the surfaces to be smooth (S-a = 0.22 mu m). Incubation with a consortium of S. sanguinis and A. naeslundii showed no differences in adhesion between the surfaces over 2 hours. After 14 hours, the level of biofilm growth was low and again, no differences between the surfaces were seen. The presence of saliva increased the biofilm biovolume of S. sanguinis and A. naeslundii ten-fold compared to when saliva was absent and this was due to increased adhesion rather than biofilm growth. Conclusions: Nano-topographical modification of smooth titanium surfaces had no effect on adhesion or early biofilm formation by S. sanguinis and A. naeslundii as compared to turned surfaces or those treated with anodic oxidation in the presence of Ca2+. The presence of saliva led to a significantly greater biofilm biovolume but no significant differences were seen between the test surfaces. These data thus suggest that modification with sol-gel derived nanoporous TiO2, which has been shown to improve osseointegration and soft-tissue healing in vivo, does not cause greater biofilm formation by the two oral commensal species tested than the other surfaces.

  • 266.
    Garvin, Peter
    et al.
    Linköping University, Department of Medical and Health Sciences, Social Medicine and Public Health Science. Linköping University, Faculty of Health Sciences.
    Suska, Anke
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Kristenson, Margareta
    Linköping University, Department of Medical and Health Sciences, Social Medicine and Public Health Science. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Public Health Sciences.
    Lundström, Ingemar
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Ernerudh, Jan
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Immunology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Immunology and Transfusion Medicine.
    SALIVARY ALPHA-AMYLASE IN A POPULATION BASED SAMPLE. ASSOCIATIONS WITH PSYCHOSOCIAL FACTORS, SELF RATED HEALTH AND INFLAMMATORY MARKERS2010In: International Journal of Behavioral Medicine, ISSN 1070-5503, E-ISSN 1532-7558, Vol. 17, no 1 Supplement, p. S181-S181Article in journal (Other academic)
    Abstract [en]

    Objective: In recent years, salivary alpha-amylase (sAA) has beenproposed as a reliable proxy for sympathetic activity. This study aimed at testing the association between sAA to a broad range of psychosocial factors, self rated health, cardiovascular risk factors and inflammatory markers in a normal population sample.

    Methods: 30 participants, all men between 50 and 54 years old, were randomly selected from a normal population based study. Saliva samples were collected at awakening, 30 minutes after awakening and just before going to bed. sAA was measured by a calorimetric method using Phadebas amylase test. Linear regression models were used to test associations between sAA levels and a broad spectrum of psychosocial factors (e.g. depressive symptamology, vital exhaustion, mastery and sense of coherence) self rated health and inflammatory markers (e.g. C-reactive protein). Adjustments were made for physical exercise, smoking, blood  lipids and  time point  when  sample was collected.

    Results: sAA levels at awakening were positively associated with depressive symptamology (p = 0.046), vital exhaustion (p = 0.025) and negatively associated with sense of coherence (p = 0.034). It was further associated positively associated with levels of C-reactive protein (p = 0.024)  and  negatively associated with  self  reported general health (p = 0.010). Samples taken just before going to bed were showing similar results, whereas samples taken 30 minutes after awakening only showed a few significant associations.

    Conclusions: The associations found give further support for the use of salivary alpha amylase as a psychoneuroendocrinological bio- marker. Assessment just after awakening or just before going to bed seems to be more reliable than samples 30 minutes after awakening.

  • 267.
    Gatto, E.
    et al.
    Department of Chemical Sciences and Technologies, University of Rome Tor Vergata, Via della Ricerca Scientifica, 00133 Rome, Italy.
    Malik, Muhammad Ali
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Di, Natale C.
    Di Natale, C., Department of Electronic Engineering, University of Rome Tor Vergata, Via del Politecnico 1, 00133 Rome, Italy.
    Paolesse, R.
    Department of Chemical Sciences and Technologies, University of Rome Tor Vergata, Via della Ricerca Scientifica, 00133 Rome, Italy.
    D'Amico, A.
    Department of Electronic Engineering, University of Rome Tor Vergata, Via del Politecnico 1, 00133 Rome, Italy.
    Lundström, Ingemar
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Filippini, Daniel
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Polychromatic fingerprinting of excitation emission matrices2008In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 14, no 20, p. 6057-6060Article in journal (Refereed)
    Abstract [en]

    The ability of a ubiquitous polychromatic excitation to support the fingerprinting of the Excitation Emission Matrices (EEM) of fluorescent indicators was reported. Solutions of fluorescent molecules, with concentration of 2µM for the absorption and 10µM for the emission measurements were prepared. Spectroscopic grade THF and distilled water passed through Milli-Q purification system were used as solvents. EEM measurements were carried out on a spectrofluorimeter, operating in the 390-700 nm detection range, with excitations at 20 nm intervals within the same range. During the measurement, the screen displayed a sequence of 50 colors and for every color, the transmission and emission spectrum of both the reference and the sample were recorded. Illuminating colors in the red region are not able to excite fluorescence and this can be seen in the spectra for red light.

  • 268.
    Goransson, A.
    et al.
    Göransson, A., Department of Biomaterial Science, Institute of Surgical Science, Göteborg University, Göteborg, Sweden, Department of Prosthetic Dentistry/Dental Material Science, Sahlgrenska Academy, Göteborg University, Göteborg, Sweden, Department of Biomaterial Science, Department of Prosthetic Dentistry/Dental Material Science, Göteborg University, SE 405 30 Göteborg, Sweden.
    Gretzer, C.
    Department of Biomaterial Science, Institute of Surgical Science, Göteborg University, Göteborg, Sweden.
    Tengvall, Pentti
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Wennerberg, A.
    Department of Biomaterial Science, Institute of Surgical Science, Göteborg University, Göteborg, Sweden, Department of Prosthetic Dentistry/Dental Material Science, Sahlgrenska Academy, Göteborg University, Göteborg, Sweden.
    Inflammatory response to titanium surfaces with fibrinogen and catalase coatings: An in vitro study2007In: Journal of Biomedical Materials Research - Part A, ISSN 1549-3296, Vol. 80, no 3, p. 693-699Article in journal (Refereed)
    Abstract [en]

    The aim of the present study was to evaluate the possibility to modulate the early inflammatory response in vitro by coating titanium surfaces with candidate proinflammatory (fibrinogen coated turned titanium "Fib") and antiinflammatory proteins (catalase on top of fibrinogen coated turned titanium "Cat"). Additionally, turned titanium surfaces (Ti) were used as controls. The discs were incubated with human mononuclear cells. Adhered cells were investigated with respect to number, viability, differentiation (acute marker 27E10 vs. chronic marker RM3/1), and cytokine production (TNF-a and IL-10), after 24 and 72 h. The results indicated that it is possible to modulate the inflammatory response with protein coatings. However, the strongest inflammatory response, indicated by increased number of adhered cells and release of pro and antiinflammatory mediators, was induced by Cat. Furthermore, the cytokine production on this surface was not sensitive to LPS stimulation. Differentiation measured as the expression of the chronic cell surface marker, dominated after 72 h for all surface modifications and Cat displayed an increased number compared to the others. A decrease in the total number of adhered cells and amounts of TNF-a were observed on all surfaces over time. The cell viability was, in general, high for all tested surfaces. In conclusion, the study proved it possible to influence the early inflammatory response in vitro by immobilizing protein coatings to titanium surfaces. However, the catalase surface demonstrated the strongest inflammatory response, and the possibility to selectively use the potent antiinflammatory capacity of catalase needs to be further evaluated. © 2006 Wiley Periodicals, Inc.

  • 269.
    Goransson, A.
    et al.
    Göransson, A., Department of Biomaterial Science, Institute of Surgical Science, Göteborg University, Göteborg 40530, Sweden, Department of Prosthetic Dentistry/Dental Material Science, Box 412, Göteborg University, Göteborg 40530, Sweden.
    Jansson, Eva
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Tengvall, Pentti
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Wennerberg, A.
    Department of Biomaterial Science, Institute of Surgical Science, Göteborg University, Göteborg 40530, Sweden, Department of Prosthetic Dentistry/Dental Material Science, Box 412, Göteborg University, Göteborg 40530, Sweden.
    Bone formation after 4 weeks around blood-plasma-modified titanium implants with varying surface topographies: An in vivo study2003In: Biomaterials, ISSN 0142-9612, E-ISSN 1878-5905, Vol. 24, no 2, p. 197-205Article in journal (Refereed)
    Abstract [en]

    The aim of the present study was to investigate and compare the stability and bone ingrowth capacity to screw-shaped titanium implants with five different surface treatments. The implants were: (1) standard turned with a thin blood plasma coat (TP), (2) NaOH-etched dito with pore size 0.2-0.3µm (E), (3) NaOH-etched with pore size 0.2-0.3µm and a thin blood plasma coat (EP), (4) electrochemically oxidised with pore size 1-2µm (O), (5) electrochemically oxidised with pore size 1-2µm and a thin blood plasma coat (OP). A total of 66 implants were divided into the above-described five groups and inserted for 4 weeks into tibia and femur of 11 rabbits. The implants were evaluated by resonance frequency (RF) measurements at the time of insertion and removal, and analysed histomorphometrically at removal. The RF measurements showed that the implant stability was lower in soft bone compared to dense and increased with time. No significant differences were observed between the different surface modifications. The histomorphometric analysis revealed no statistically significant differences between the implants regarding bone-to-metal contact (BMC) and bone area inside the threads (BA). The above results indicate that thin blood plasma-coated and non-coated screw-shaped titanium implants with turned, NaOH-etched and electrochemically etched surface profiles integrate similarly to bone at 1 month of implantation. © 2002 Elsevier Science Ltd. All rights reserved.

  • 270.
    Granlund, Thomas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Theander, Mathias
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Berggren, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Andersson, M
    Chalmers Tekniska Högskola.
    Ruzeckas, A
    Lunds universitet.
    Sundström, V
    Lunds universitet.
    Björk, G
    KTH.
    Granström, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    A polythiophene microcavity laser1998In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 288, no 5-6, p. 879-884Article in journal (Refereed)
    Abstract [en]

    We report photopumped lasing in a microcavity device with a polythiophene layer as the emitter. These microcavity devices are built by joining two polymer coated dielectric mirrors at elevated temperature. When photopumping the film, a lasing threshold is observed at 120 nJ/cm(2). Comparative studies with fast pump-probe spectroscopy of thin polythiophene films and the same polymer in photopumped lasing studies, indicate that the gain coefficient is 80 +/- 20 cm(-1), and that the exciton concentration is 2 X 10(17) cm(-3) at the lasing transition, well below the exciton-exciton recombination level. (C) 1998 Elsevier Science B.V. All rights reserved.

  • 271.
    Granlund, Thomas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Theander, Mathias
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Berggren, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Andersson, Mats
    Chalmers Tekniska Högskola.
    Ruzeckas, A
    Lunds universitet.
    Sundström, V
    Lunds universitet.
    Björk, G
    KTH.
    Granström, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Lasing in substituted polythiophene between dielectric mirrors1999In: Synthetic metals, ISSN 0379-6779, E-ISSN 1879-3290, Vol. 102, no 1-3, p. 1038-1041Article in journal (Refereed)
    Abstract [en]

    We report photopumped lasing in a microcavity device with a polythiophene layer as emitter. The microcavity is made of a polymer film between two dielectric Bragg reflecting mirrors (DBR). The:microcavity devices is built by joining two polymer coated DBR mirrors at elevated temperature. When photopumping the film,a lasing threshold is observed at 120 nJ/cm(2). Comparative studies with fast pump-probe spectroscopy of thin polythiophene films, and the same polymer in photopumped lasing studies, indicate that the gain coefficient is 80 +/- 20 cm(2) and that the exciton concentration is 2X10(17) cm(2) at the lasing transition, well below the exciton-exciton recombination level.

  • 272.
    Granström, Magnus
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Berggren, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Micrometer- and Nanometer-Sized Polymeric Light-Emitting Diodes1995In: Science, ISSN 0036-8075, E-ISSN 1095-9203, Vol. 267, no 5203, p. 1479-1481Article in journal (Refereed)
    Abstract [en]

    A method for the fabrication of micrometer- and submicrometer-sized polymeric light-emitting diodes is presented. Such diodes have a variety of applications. Light sources of dimensions around 100 nanometers are required for subwavelength, near-field optical microscopy. Another possible application is patterning on the micrometer and nanometer scale. The diodes have been made in the form of a sandwich structure, with the conductive polymer poly(3,4-ethylene-dioxythiophene) polymerized in the pores of commercially available microfiltration membranes defining the hole-injecting contacts, poly[3-(4-octylphenyl)-2,2-bithiophene] as the light-omitting layer, and a thin film of calcium-aluminum as the electron injector.

  • 273.
    Granström, Magnus
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Berggren, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Polymeric light-emitting diodes of submicron size - Structures and developments1996In: Synthetic metals, ISSN 0379-6779, E-ISSN 1879-3290, Vol. 76, no 1-3, p. 141-143Article in journal (Refereed)
    Abstract [en]

    Micron- and submicron-sized light-emitting diodes (LEDs) made using conjugated polymers as electroluminescent layers and contact materials are presented. Two different routes to make arrays of such small light sources have been developed. The benefits and drawbacks of the use of the conjugated polymer poly(2,3-ethylene-dioxythiophene) (PEDOT) as hole injector in polymer LEDs are also discussed.

  • 274.
    Granström, Magnus
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Berggren, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Andersson, Mats R.
    Chalmers Tekniska Högskola.
    Hjertberg, T.
    Chalmers Tekniska Högskola.
    Wennerström, O.
    Chalmers Tekniska Högskola.
    Phase separation of conjugated polymers - Tools for new functions in polymer LEDs1997In: Synthetic metals, ISSN 0379-6779, E-ISSN 1879-3290, Vol. 85, no 1-3, p. 1193-1194Article in journal (Refereed)
    Abstract [en]

    Within the single family of substituted poly(thiophenes) it is possible to realize such diverse device designs as voltage controlled colours from polymer LEDs, sub-micron size LEDs, and white light emitters. Many of these features become possible by the use of polymer blends in which one or more poly(thiophenes) are mixed with a matrix polymer (PMMA). The phase structure in these blends can be controlled by stoichiometry and mode of formation. That phase structure can be used to prevent exciton transfer, and to define new colours in polymer LEDs. It also allows us to make anisotropic conductors suitable for contacting optical devices.

  • 275.
    Granström, Magnus
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Berggren, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Pede, Danilo
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Andersson, Mats R.
    Chalmers Tekniska Högskola.
    Hjertberg, T.
    Chalmers Tekniska Högskola.
    Wennerström, O.
    Chalmers Tekniska Högskola.
    Self organizing polymer films - a route to novel electronic devices based on conjugated polymers1997In: Supramolecular science, ISSN 0968-5677, E-ISSN 1873-4146, Vol. 4, no 1-2, p. 27-34Article in journal (Refereed)
    Abstract [en]

    Polymer blends are often used in polymer light emitting diodes as a tool to increase the efficiency of the devices. In this report, we show the necessity to take the phase separation properties of such blends into account, as the miscibility of the involved polymers drastically affects the resulting film structure. By using phase separated polymer blends involving conjugated poly(thiophenes) and different nonconjugated polymers as matrices, different types of applications, such as light emitting diodes with improved voltage control of emitted colour, sub-micron size LEDs and anisotropic conductors are demonstrated. (C) 1997 Elsevier Science Ltd. All rights reserved.

  • 276.
    Gutes, A.
    et al.
    Gutés, A., Sensors and Biosensors Group, Department of Chemistry, Autonomous University of Barcelona, Edifici Cn, 08193 Bellaterra, Spain.
    Cespedes, F.
    Sensors and Biosensors Group, Department of Chemistry, Autonomous University of Barcelona, Edifici Cn, 08193 Bellaterra, Spain.
    del, Valle M.
    del Valle, M., Sensors and Biosensors Group, Department of Chemistry, Autonomous University of Barcelona, Edifici Cn, 08193 Bellaterra, Spain.
    Louthander, D.
    Krantz-Rülcher, Christina
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Winquist, Fredrik
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    A flow injection voltammetric electronic tongue applied to paper mill industrial waters2006In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 115, no 1, p. 390-395Article in journal (Refereed)
    Abstract [en]

    A voltammetric electronic tongue with automated operation based on the flow injection (FIA) technique was applied to the characterization of wastewaters coming from the paper mill industry. A metallic multielectrode array - formed by platinum, gold and rhodium electrodes - was employed as the detection system, while the measurements were based on large amplitude pulse voltammetry (LAPV). LAPV consisted in scans of pulses from to 0 to 1.8 V at 0.2 V steps. Five current values were recorded for each pulse, so a set of 300 current values (three electrodes × 20 pulses × five values) was recorded for each sample. Samples were first discriminated using Principal Component Analysis (PCA), while Artificial Neural Networks were used for the characterization and prediction of chemical oxygen demand, conductivity and pH. The system may be used for the quick identification and monitoring of the quality of used waters in these industrial facilities. © 2005 Elsevier B.V. All rights reserved.

  • 277.
    H Labrador, Roberto
    et al.
    Molecular Chemistry Applied Institute, Polytechnical University of Valencia. Camino de Vera, s/n. þ34 963877343, 46022 Valencia, Spain.
    Olsson, John
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics . Linköping University, The Institute of Technology.
    Winquist, Fredrik
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics . Linköping University, The Institute of Technology.
    Martinez-Manez, Ramon
    University Politecn Valencia.
    Sotoa, Juan
    Molecular Chemistry Applied Institute, Polytechnical University of Valencia. Camino de Vera, s/n. þ34 963877343, 46022 Valencia, Spain.
    Determination of Bisulfites in Wines with an Electronic Tongue Based on Pulse Voltammetry2009In: Electroanalysis, ISSN 1040-0397, E-ISSN 1521-4109, Vol. 21, no 3-5, p. 612-617Article in journal (Refereed)
    Abstract [en]

    An electronic tongue (ET) based on pulse voltammetry is used to predict concentrations of bisulfites in wine samples. The ET array consists of four working electrodes (gold, rhodium, platinum and stainless steel) encapsulated into a stainless steel cylinder used at the same time as both the body of the ET system and the pseudoreference/counter electrode. The ET device is additionally equipped with a self-polishing system. Multivariate analysis including Cross validation and partial least square (PLS) techniques are applied for data management and prediction models building. Ascorbic acid and histamine have also been included in the predictive analysis.

  • 278.
    Hammarström, Per
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biochemistry. Linköping University, The Institute of Technology.
    Ali, Malik M
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Mishra, Rajesh
    Linköping University, Department of Physics, Chemistry and Biology, Biochemistry. Linköping University, The Institute of Technology.
    Salagic, Belma
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Svensson, Samuel
    AstraZeneca RandD.
    Tengvall, Pentti
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Lundström, Ingemar
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    An Auto-Catalytic Surface for Conformational Replication of Amyloid Fibrils-Genesis of an Amyloid World?2011In: Origins of life and evolution of the biosphere, ISSN 0169-6149, E-ISSN 1573-0875, Vol. 41, no 4, p. 373-383Article in journal (Refereed)
    Abstract [en]

    Amyloid fibrils are composed of self assembled stacked peptide or protein molecules folded and trapped in a stable cross-beta-sheet conformation. The amyloid fibrillation mechanism represents an intriguing self-catalyzed process rendering replication of a molecular conformational memory of interest for prebiotic chemistry. Herein we describe how a solid surface can be rendered auto-catalytic for fibrillation of a protein solution. We have discovered that a hydrophobic silicon or glass surface can be made to continuously fibrillate solutions of insulin monomers under stressed conditions (pH 1.6, 65 degrees C). It was found that the surface acts as a platform for the formation of nascent seeds that induce fibril replication on and at the surface. This autocatalytic effect stems from a layer a few insulin molecules thick representing an oligomeric layer of misfolded, conformationally trapped, insulin molecules that rapidly through epitaxial growth catalyze the rate determining step (nucleation) during fibril replication. This autocatalytic layer is generated by the protein-solid surface interaction and conformational changes of the adsorbed protein during exposure at the air-water interface. The resulting autocatalytic surface thus both initiates local conformational molecular self-replication and acts as a reservoir for fibril seeds budding off into solution spreading fibril replication entities to the surrounding medium. The possibility of catalysis of the conformational replication process by minute amounts of nucleation sites located on a recruiting surface can evade the issue of dramatic concentration dependence of amyloidogenesis.

  • 279.
    Hammarström, Per
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biochemistry. Linköping University, The Institute of Technology.
    Ali Malik, Muhammad
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Mishra, Rajesh
    Linköping University, Department of Physics, Chemistry and Biology, Biochemistry. Linköping University, The Institute of Technology.
    Svensson, Samuel
    Linköping University, Department of Medicine and Health Sciences, Pharmacology . Linköping University, Faculty of Health Sciences.
    Tengvall, Pentti
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics . Linköping University, The Institute of Technology.
    Lundström, Ingemar
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics . Linköping University, The Institute of Technology.
    A catalytic surface for amyloid fibril formation2008In: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 100Article in journal (Refereed)
    Abstract [en]

    A hydrophobic surface incubated in a solution of protein molecules (insulin monomers) was made into a catalytic surface for amyloid fibril formation by repeatedly incubate, rinse and dry the surface. The present contribution describes how this unexpected transformation occurred and its relation to rapid fibrillation of insulin solutions in contact with the surface. A tentative model of the properties of the catalytic surface is given, corroborated by ellipsometric measurements of the thickness of the organic layer on the surface and by atomic force microscopy. The surfaces used were spontaneously oxidized silicon made hydrophobic through treatment in dichlorodimethylsilane.

  • 280.
    Hansson, Kenny
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Johansen, Knut
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Wetterö, Jonas
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Rheumatology.
    Klenkar, Goran
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics.
    Benesch, Johan
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Lundström, Ingemar
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics.
    Lindahl, Tomas
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Division of clinical chemistry. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Chemistry.
    Tengvall, Pentti
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics.
    Surface plasmon resonance detection of blood coagulation and platelet adhesion under venous and arterial shear conditions2007In: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 23, no 2, p. 261-268Article in journal (Refereed)
    Abstract [en]

    A surface plasmon resonance (SPR) based flow chamber device was designed for real time detection of blood coagulation and platelet adhesion in platelet rich plasma (PRP) and whole blood. The system allowed the detection of surface interactions throughout the 6 mm length of the flow chamber. After deposition of thromboplastin onto a section of the sensor surface near the inlet of the flow chamber, coagulation was detected downstream of this position corresponding to a SPR signal of 7 to 8 mRIU (7 to 8 ng/mm2). A nonmodified control surface induced coagulation 3.5 times slower. Platelet adhesion to gold and fibrinogen coated surfaces in the magnitude of 1.25 and 1.66 mRIU was also shown with platelets in buffer, respectively. SPR responses obtained with PRP and whole blood on surfaces that were methylated or coated with von Willebrand factor (vWF), fibrinogen, or collagen, coincided well with platelet adhesion as observed with fluorescence microscopy in parallel experiments. The present SPR detection equipped flow chamber system is a promising tool for studies on coagulation events and blood cell adhesion under physiological flow conditions, and allows monitoring of short-range surface processes in whole blood. © 2007 Elsevier B.V. All rights reserved.

  • 281.
    Hansson, Kenny M.
    et al.
    Linköping University, Department of Biomedicine and Surgery, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Tengvall, Pentti
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Lundström, Ingemar
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Rånby, Mats
    Linköping University, Department of Biomedicine and Surgery, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Lindahl, Tomas L.
    Linköping University, Department of Biomedicine and Surgery, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Surface plasmon resonance and free oscillation rheometry in combination: A new approach forstudies on haemostasis and biomaterialsManuscript (preprint) (Other academic)
    Abstract [en]

    In haemostasis and biomaterial research it is important to be able to study biological processes at surfaces and in the bulk. Surface plasmon resonance (SPR) is sensitive to changes at surface and free oscillation rheometry (FOR) probes the bulk. The present work demonstrates the usefulness of the combination of the techniques for simultaneous real-time measurements on coagulation and fibrinolysis of blood plasma, as well as coagulation of whole blood. SFLLRN stimulated coagulation of native whole blood presented a higher SPR signal with a different appearance than for plasma coagulation, while the FOR signals corresponding to plasma and whole blood coagulation were similar. This result indicated that the SPR technique was more sensitive to cell-surface interactions than to fibrin formation in whole blood, while the FOR technique were equally sensitive to coagulation in whole blood and plasma. Spontaneous coagulation of native whole blood in contact with methyland hydroxyl-terminated self-assembled monolayers on gold and gold surfaces regenerated after coagulation by degradation of adsorbed proteins with trypsin and SOS were also studied. The regenerated gold surfaces displayed the shortest coagulation times, although the contact-activation of blood coagulation was found to be low. The methylated and hydroxylated surfaces were comparable in terms of coagulation activation, while the hydroxylated surfaces presented FOR signals that indicated difficulties for the coagulum to attach to the surface. The combination of SPR and FOR may be suited for studies of cell-surface interactions, and may find applications in studies of blood cell defects in patients and testing of medical substances.

  • 282.
    Hansson, Kenny
    et al.
    Linköping University, Department of Biomedicine and Surgery, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Tengvall, Pentti
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Lundström, Ingemar
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Rånby, Mats
    Linköping University, Department of Biomedicine and Surgery, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Lindahl, Tomas
    Linköping University, Department of Biomedicine and Surgery, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Comparative studies with surface plasmon resonance and free oscillation rheometry on the inhibition of platelets with cytochalasin E and monoclonal antibodies towards GPIIb/IIIa2002In: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 17, no 9, p. 761-771Article in journal (Refereed)
    Abstract [en]

    In the haemostatic system a multitude of processes are intertwined in fine-tuned interactions that arrest bleeding, keep the circulatory system open, and the blood flowing. The occurrence of both surface and bulk interactions adds an additional dimension of complexity. These insights have led to the belief that global overall procedures can inform on the likely behaviour of the system in health and disease. Two sensing procedures: surface plasmon resonance (SPR), which senses surface interactions, and free oscillation rheometry (FOR), which senses interactions within the bulk, have been combined and evaluated. The contribution of blood cells, mainly platelets, to the SPR and FOR signals was explored by simultaneous SPR and FOR measurement during native whole blood coagulation, accelerated via the platelets through addition of SFLLRN peptide and inhibition of platelet aggregation with abciximab (ReoPro®) and of shape change with cytochalasin E. The SPR technique was found to be sensitive to inhibition of blood cell functions such as adhesion to and spreading on surfaces, as well as platelet aggregation. SPR seemed not to be directly sensitive to fibrin polymerisation in coagulating whole blood. The FOR technique detected the coagulation as a bulk phenomenon, i.e. the gelation of the blood due to fibrin formation was detected. The combination of SPR and FOR may therefore be suitable for studies on blood cell functions during coagulation.

  • 283.
    Hansson, Kenny
    et al.
    Linköping University, Department of Biomedicine and Surgery, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Tengvall, Pentti
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Lundström, Ingemar
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Rånby, Mats
    Linköping University, Department of Biomedicine and Surgery, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Lindahl, Tomas
    Linköping University, Department of Biomedicine and Surgery, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Surface plasmon resonance and free oscillation rheometry in combination: a useful approach for studies on haemostasis and interactions between whole blood and artificial surfaces2002In: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 17, no 9, p. 747-759Article in journal (Refereed)
    Abstract [en]

    In haemostatic and biomaterial research biological processes at surfaces and in the bulk phase of the surface-contacting medium are important. The present work demonstrates the usefulness of the combination of surface plasmon resonance (SPR), sensitive to changes in refractive index at surfaces, and free oscillation rheometry (FOR), sensitive to rheological properties of the bulk, for simultaneous real-time measurements on coagulation and fibrinolysis of blood plasma and coagulation of whole blood. SFLLRN stimulated coagulation of native whole blood presented a higher SPR signal with different appearance than plasma coagulation, while the FOR signals corresponding to plasma and whole blood coagulation were similar. This indicated that the SPR technique was more sensitive to cell-surface interactions than to fibrin formation in whole blood during coagulation, while the FOR technique were equally sensitive to coagulation in whole blood and plasma. Spontaneous coagulation of native whole blood in contact with methyl- and hydroxyl-terminated self-assembled monolayers (SAM) on gold and gold surfaces regenerated after coagulation were also studied. The regenerated gold surfaces displayed the shortest coagulation times, although the contact-activation of blood coagulation for these surfaces was low. The methylated and hydroxylated surfaces were comparable in terms of coagulation activation, while the hydroxylated surfaces presented FOR signals that indicated detaching of the coagulum from the surface. The combination of SPR and FOR is well suited for studies of cell– and protein–surface interactions and simultaneous bulk processes. Possible applications are investigations of blood cell defects in patients and monitoring of native whole blood interactions with artificial surfaces.

  • 284.
    Hansson, Kenny
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Tosatti, Samuele
    Isaksson, Joakim
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology.
    Wetterö, Jonas
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology.
    Textor, Marcus
    Lindahl, Tomas
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Division of clinical chemistry. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Chemistry.
    Tengvall, Pentti
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics.
    Whole blood coagulation on protein adsorption-resistant PEG and peptide functionalised PEG-coated titanium surfaces2005In: Biomaterials, ISSN 0142-9612, E-ISSN 1878-5905, Vol. 26, no 8, p. 861-872Article in journal (Refereed)
    Abstract [en]

    The aim of this study was to investigate whole blood coagulation on low blood plasma protein adsorbing surfaces. For this purpose, the polycationic graft copolymer poly(L-lysine)-g-poly(ethylene glycol) (PLL-g-PEG), PLL-g-PEG grafted with a cell adhesive peptide containing the amino acid sequence -Arg-Gly-Asp- (RGD), and PLL-g-PEG with a control peptide -Arg-Asp-Gly- (RDG) were adsorbed onto titanium (oxide), forming stable monomolecular adlayers through electrostatic attraction. Free oscillation rheometry and complementary techniques were used to measure the coagulation time (CT) and other interactions of the surfaces with native whole blood, recalcified platelet-rich plasma (PRP), and recalcified citrated platelet-free plasma (PFP). The results show that the uncoated titanium surfaces (reference) activated platelets and quickly triggered the coagulation cascade via the intrinsic pathway, whereas the PLL-g-PEG surfaces displayed a prolonged CT, approximately 2-3 times longer compared to uncoated titanium. We hypothesise that blood coagulates outside the vascular system independent of low protein adsorption to or activation by surfaces, due to the absence of an active down-regulation of procoagulative processes by the vascular endothelium.

  • 285.
    Hansson, Kenny
    et al.
    Linköping University, Department of Biomedicine and Surgery, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Vikinge, T. P.
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, Faculty of Health Sciences.
    Rånby, M.
    Linköping University, Department of Biomedicine and Surgery, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Tengvall, Pentti
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Lundström, Ingemar
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Johansen, Knut
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, Faculty of Health Sciences.
    Lindahl, Tomas
    Linköping University, Department of Biomedicine and Surgery, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Surface plasmon resonance (SPR) analysis of coagulation in whole blood with application in prothrombin time assay1999In: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 14, no 8-9, p. 671-682Article in journal (Refereed)
    Abstract [en]

    It is previously shown that surface plasmon resonance (SPR) can be used to study blood plasma coagulation. This work explores the use of this technique for the analysis of tissue factor induced coagulation, i.e. prothrombin time (PT) analysis, of whole blood and plasma. The reference method was nephelometry. The prothrombin time analysis by SPR was performed by mixing two volumes of blood/plasma, one volume of thromboplastin, and one volume of CaCl2 solution directly on a sensor surface. The measurements show good agreement between nephelometry and SPR plasma analysis and also between SPR plasma and whole blood analysis. The effect of anticoagulant treatment on the clotting times was significant both quantitatively and qualitatively. The impact on the SPR signal of different physiological events in the coagulation process is discussed, and tentative interpretations of the sensorgram features are given. The major advantage of the SPR method compared to nephelometry is the possibility to perform analysis on whole blood instead of plasma. In conclusion, SPR is a promising method for whole blood coagulation analysis.

  • 286. Hansson, KM
    et al.
    Vikinge, TP
    Linkoping Univ Hosp, Dept Clin Chem, S-58185 Linkoping, Sweden Linkoping Univ, Forum Scientum Grad Sch, Linkoping, Sweden.
    Ranby, M
    Linkoping Univ Hosp, Dept Clin Chem, S-58185 Linkoping, Sweden Linkoping Univ, Forum Scientum Grad Sch, Linkoping, Sweden.
    Tengvall, Pentti
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Lundström, Ingemar
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Lindahl, Tomas
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry.
    Surface plasmon resonance (SPR) analysis of coagulation in whole blood with application in prothrombin time assay1999In: Thrombosis and Haemostasis, ISSN 0340-6245, p. 917-Conference paper (Other academic)
  • 287.
    Hedborg, Eva
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Spetz, Anita
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Winquist, Fredrik
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Lundström, Ingemar
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Polymer membranes for modification of the selectivity of field-effect gas sensors1992In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 7, no 1-3, p. 661-664Article in journal (Refereed)
    Abstract [en]

    Polymer membranes are used to increase the selectivity to certain gases of metal silicon dioxide-semiconductor (MOS) structures. Other parameters which influence the selectivity of MOS structures are the type of gate metal, its microstructure (dense or porous) and the operating temperature of the device. Photoresists as membranes can be patterned by photolithographic methods. Membranes, 1-2-mu-m thick, of positive and negative photoresist are applied on MOS capacitors with 6 nm iridium as the gate metal, operated at 150-degrees-C. The influence of the membranes on the response to three gases, hydrogen, ammonia and ethanol, has been investigated. The hydrogen response decreases bv about half with the use of a photoresist membrane. The ammonia response shows a characteristic change in the kinetics, while the ethanol response almost disappears. Positive and negative resist influence the gas response in similar ways, in spite of their different molecular structures.

  • 288.
    Holmberg, Martin
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Gustafsson, Fredrik
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Hörnsten, Gunnar
    SIK, The Swedish Institute for Food and Biotechnology, Ideon Lund.
    Winquist, Fredrik
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Nilsson, Lennart E.
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Microbiology. Linköping University, Faculty of Health Sciences.
    Ljung, Lennart
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Lundström, Ingemar
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Bacteria classification based on feature extraction from sensor data1998In: Biotechnology techniques, ISSN 0951-208X, E-ISSN 1573-6784, Vol. 12, no 4, p. 319-324Article in journal (Refereed)
    Abstract [en]

    Data evaluation and classification have been made on measurements by an electronic nose on the headspace of samples of different types of bacteria growing on petri dishes. The chosen groups were: Escherichia coli, Enterococcus sp., Proteus mirabilis, Pseudomonas aeruginosa, and Staphylococcus saprophytica. An approximation of the response curve by time was made and the parameters in the curve fit were taken as important features of the data set. A classification tree was used to extract the most important features. These features were then used in an artificial neural network for classification. Using the ‘leave-one-out’ method for validating the model, a classification rate of 76% was obtained

  • 289.
    Holmin, Susanne
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Björefors, Fredrik
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Eriksson, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Krantz-Rulcker, Christina
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Winquist, Fredrik
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Investigation of Electrode Materials as Sensors in a Voltammetric Electronic Tongue2002In: Electroanalysis, ISSN 1040-0397, E-ISSN 1521-4109, Vol. 14, no 12, p. 839-847Article in journal (Refereed)
    Abstract [en]

    In this work different electrode materials were investigated as sensors in a voltammetric electronic tongue. Basically, the electronic tongue is based on the combination of nonspecific sensors (electrodes) and pattern recognition tools, for example principal component analysis (PCA). Copper. glassy carbon, nickel, palladium, silver, tin, titanium and zirconium together with more traditional electrode materials such as gold, iridium, and platinum were studied. Cyclic voitammetry was applied to study typical model reactions in solutions containing different electroactive compounds, like ascorbic acid, glucose, histidine and potassium hexacyanoferrate(II). Different sensitivity and selectivity were obtained with the electrodes. Large responses were for example found for the amino acid and the carbohydrate using the copper, nickel and silver electrode. Some of the electrodes were employed in multicomponent solutions, i.e., liquid washing detergents from different suppliers together with differential pulse voltammetry. Responses from the electrodes in combination with PCA showed that they separated the detergents to different extents. This was further used when information from the sensors was merged together for successful discrimination of the detergents. It was found that two detergents close to each other in the score plot were from the same supplier. Furthermore. scanning electron microscopy (SEM) was used to monitor surface changes at the nonnoble electrodes (copper, nickel, and silver).

  • 290.
    Holmin, Susanne
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Krantz-Rülcher, Christina
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Lundström, Ingemar
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Winquist, Fredrik
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Drift correction of electronic tongue responses2001In: Measurement science and technology, ISSN 0957-0233, E-ISSN 1361-6501, Vol. 12, no 8, p. 1348-1354Article in journal (Refereed)
    Abstract [en]

    In this article, drift correction algorithms were used in order to remove linear drift in multivariate spaces of two data sets obtained by an electronic tongue based on voltammetry. The electronic tongue consisted of various metal electrodes (Au, Ir, Pt, Rh) combined with pattern recognition tools, such as principal component analysis. The first data set contained different types of liquid, from well defined to more complex solutions. The second data set contained different black and green teas. Component correction (CC) was compared to a simple additive correction. In CC, the drift direction of measured reference solutions in a multivariate space was subtracted from other types of solution. In additive correction, responses from reference samples were subtracted from other samples. CC showed similar or better performance in reducing drift compared to additive correction for the two data sets. The additive correction method was dependent on the fact that the differences in between samples of a reference solution were similar to the changes in between samples of other liquids, which was not the case with CC.

  • 291.
    Holmin, Susanne
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Krantz-Rülcher, Christina
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Winquist, Fredrik
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Multivariate optimisation of electrochemically pre-treated electrodes used in a voltammetric electronic tongue2004In: Analytica Chimica Acta, ISSN 0003-2670, E-ISSN 1873-4324, Vol. 519, no 1, p. 39-46Article in journal (Refereed)
    Abstract [en]

    The use of experimental design as a tool to optimise electrochemically cleaned electrodes applied in a voltammetric electronic tongue is described. A simple and quick activation of electrode surfaces is essential for this type of device, especially for on-line applications in industrial processes. The electronic tongue consisted of four metal electrodes, e.g. Au, Ir, Pt, and Rh in a three-electrode configuration. Current was measured as a function of large potential pulses of decreasing amplitude applied to each electrode. Preliminary results showed that electrochemical cleaning activated the electrode surfaces to similar extent as polishing. Settings of potential and time for each electrode was determined with experimental design in a solution containing 1.0 mM K 4[Fe(CN)6] in 0.1 M phosphate buffer (pH 6.8). Electrode surfaces were deactivated in-between measurements in a complex liquid, like tea. Optimal settings for potential and time in the electrochemical cleaning procedure at each electrode were chosen at recoveries of 100% (compared to polished electrodes). The recoveries were larger than 100% when too large potentials and times were applied. This could be explained by the fact that the electrode areas increased and therefore also the current responses. Principal component analysis (PCA) was used to investigate the stability of the electrode settings at 100% recoveries. No obvious trends of drift in the signals were found. © 2004 Elsevier B.V. All rights reserved.

  • 292.
    Holmin, Susanne
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Spångéus, Per
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Krantz-Rülcher, Christina
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Winquist, Fredrik
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Compression of electronic tongue data based on voltammetry - A comparative study2001In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 76, no 1-3, p. 455-464Conference paper (Other academic)
    Abstract [en]

    In this paper, three data compression methods are investigated to determine their ability to reduce large data sets obtained by a voltammetric electronic tongue without loss of information, since compressed data sets will save data storage and computational time. The electronic tongue is based on a combination of non-specific sensors and pattern recognition tools, such as principal component analysis (PCA). A series of potential pulses of decreasing amplitude are applied to one working electrode at a time and resulting current transients are collected at each potential step. Voltammograms containing up to 8000 variables are subsequently obtained. The methods investigated are wavelet transformation (WT) and hierarchical principal component analysis (HPCA). Also, a new chemical/physical model based on voltammetric theory is developed in order to extract interesting features of the current transients, revealing different information about species in solutions. Two model experiments are performed, one containing solutions of different electroactive compounds and the other containing complex samples, such as juices from fruits and tomatoes. It is shown that WT and HPCA compress the data sets without loss of information, and the chemical/physical model improves the separations slightly. HPCA is able to compress the two data sets to the largest extent, from 8000 to 16 variables. When data sets are scaled to unit variance, the separation ability improves even further for HPCA and the chemical/physical model. © 2001 Elsevier Science B.V.

  • 293.
    Hook, F.F
    et al.
    Department of Applied Physics, Chalmers Institute of Technology, SE-412 96 Göteborg, Sweden.
    Voros, J.
    Vörös, J., Laboratory for Surface Science and Technology, Department of Materials, Swiss Federal Institute of Technology, CH-8092 Zürich, Switzerland.
    Rodahl, M.
    Department of Applied Physics, Chalmers Institute of Technology, SE-412 96 Göteborg, Sweden.
    Kurrat, R.
    Laboratory for Surface Science and Technology, Department of Materials, Swiss Federal Institute of Technology, CH-8092 Zürich, Switzerland.
    Boni, P.
    Böni, P., Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland.
    Ramsden, J.J.
    Department of Biophysical Chemistry, Biocenter of the University, CH-4056 Basel, Switzerland.
    Textor, M.
    Laboratory for Surface Science and Technology, Department of Materials, Swiss Federal Institute of Technology, CH-8092 Zürich, Switzerland.
    Spencer, N.D.
    Laboratory for Surface Science and Technology, Department of Materials, Swiss Federal Institute of Technology, CH-8092 Zürich, Switzerland.
    Tengvall, Pentti
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Gold, J.
    Department of Applied Physics, Chalmers Institute of Technology, SE-412 96 Göteborg, Sweden.
    Kasemo, B.
    Department of Applied Physics, Chalmers Institute of Technology, SE-412 96 Göteborg, Sweden.
    A comparative study of protein adsorption on titanium oxide surfaces using in situ ellipsometry, optical waveguide lightmode spectroscopy, and quartz crystal microbalance/dissipation2002In: Colloids and Surfaces B: Biointerfaces, ISSN 0927-7765, E-ISSN 1873-4367, Vol. 24, no 2, p. 155-170Article in journal (Refereed)
    Abstract [en]

    The adsorption kinetics of three model proteins - human serum albumin, fibrinogen and hemoglobin - has been measured and compared using three different experimental techniques: optical waveguide lightmode spectroscopy (OWLS), ellipsometry (ELM) and quartz crystal microbalance (QCM-D). The studies were complemented by also monitoring the corresponding antibody interactions with the pre-adsorbed protein layer. All measurements were performed with identically prepared titanium oxide coated substrates. All three techniques are suitable to follow in-situ kinetics of protein-surface and protein-antibody interactions, and provide quantitative values of the adsorbed adlayer mass. The results have, however, different physical contents. The optical techniques OWLS and ELM provide in most cases consistent and comparable results, which can be straightforwardly converted to adsorbed protein molar ('dry') mass. QCM-D, on the other hand, produces measured values that are generally higher in terms of mass. This, in turn, provides valuable, complementary information in two respects: (i) the mass calculated from the resonance frequency shift includes both protein mass and water that binds or hydrodynamically couples to the protein adlayer, and (ii) analysis of the energy dissipation in the adlayer and its magnitude in relation to the frequency shift (c.f. adsorbed mass) provides insight about the mechanical/structural properties such as viscoelasticity. © 2002 Elsevier Science B.V. All rights reserved.

  • 294.
    Häggblad, Erik
    et al.
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Petersson, Henrik
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Ilias, Michail A.
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Anderson, Chris D
    Linköping University, Department of Clinical and Experimental Medicine, Dermatology and Venerology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Centre, Department of Dermatology and Venerology in Östergötland.
    Salerud, Göran
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    A diffuse reflectance spectroscopic study of UV-induced erythematous reaction across well-defined borders in human skin2010In: Skin research and technology, ISSN 0909-752X, E-ISSN 1600-0846, Vol. 16, no 3, p. 283-290Article in journal (Refereed)
    Abstract [en]

    Introduction The colour of tissue is often of clinicaluse in the diagnosis of tissue homeostasis andphysiological responses to various stimuli.Determining tissue colour changes and borders,however, often poses an intricate problem and visualexamination, constituting clinical praxis, does notallow them to be objectively characterized orquantified. Demands for increased inter- and intraobserverreproducibility have been incentives for theintroduction of objective methods and techniques fortissue colour (e.g. erythema) evaluation. The aim ofthe present paper was to study the border zone of anUVB provoked erythematous response of humanskin in terms of blood volume and oxygenationmeasured by means of diffuse reflectancespectroscopy using a commercial probe.

    Material and Methods A provocation model, basedon partial masking of irradiated skin areas, definestwo erythema edges at every skin site responding tothe UV irradiation. In every subject, 5 test sites wereexposed with a constant UV light irradiance (14mW/cm2), but with different exposures times (0, 3,6, 9, 12 seconds). An analysis of the spectral datameasured across the two edges was performed for every scan line. The oxygenized and deoxygenizedhemoglobin contents were estimated in everymeasurement point, using a modified Beer-Lambertmodel.

    Results The fit of the experimental data to the model derived by the modified Beer-Lambert law was excellent (R2>0.95). Analyzing data for the chromophore content showed that the erythematous response in provoked areas is dominated by the increase in oxyhemoglobin. The width for the left and right border zone was estimated to 1.81±0.93 mm and 1.90±0.88 mm respectively (M±SD). The unprovoked area between the two edges was estimated to 0.77±0.68 mm.

    Conclusion While the chosen data analysis performed satisfactory, the ability of the probe design to differentiate spatial aspects of a reaction with abrupt borders was found to be suboptimal resulting in a probable overestimation of the erythematous edge slope. Probe modification or imaging are possible solutions.

  • 295.
    Ieva, Eliana
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Buchholt, Kristina
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Colaianni, L
    University of Bari.
    Cioffi, N
    University of Bari.
    Sabbatini, L
    University of Bari.
    Capitani, G C
    University of Bari.
    Lloyd Spetz, Anita
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Käll, Per-Olov
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Physical Chemistry.
    Torsi, L
    University of Bari.
    Au Nanoparticles as Gate Material for NOx Field Effect Capacitive Sensors2008In: Sensor letters, ISSN 1546-198X, Vol. 6, no 4, p. 577-584Article in journal (Refereed)
    Abstract [en]

    Gold nanoparticles (Au-NPs) are electrochemically synthesized in the presence of tetra-alkylammonium stabilizers and used as active element in Field Effect capacitive gas sensors. Before use, the sensing area is treated by a relatively mild annealing procedure aimed to partially remove the organic stabilizer without loosing the nano-structured character of the particles. Both pristine and annealed materials have been subjected to a spectroscopic and morphological characterization (by means of UV-Vis, XPS, TEM, SEM techniques). Preliminary results on the application of AuNPs as gate material for NO, sensing are reported. The sensor is able to detect NO, with appreciable selectivity and low response towards the other tested gases (C3H6, CO, H-2, NH3).

  • 296.
    Ieva, Eliana
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Buchholt, Kristina
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Colaianni, L
    Dipartimento di Chimica, Università degli Studi di Bari, Italy .
    van der Werf, I.D.
    Dipartimento di Chimica, Università degli Studi di Bari, Italy .
    Lloyd Spetz, Anita
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Käll, Per-Olov
    Linköping University, Department of Physics, Chemistry and Biology, Physical Chemistry. Linköping University, The Institute of Technology.
    Torsi, L
    Dipartimento di Chimica, Università degli Studi di Bari, Bari, Italy .
    Gold Nanoparticle Sensors For Environmental Pollutant Monitoring2007In: Proceedings of the 2007 2nd IEEE International Workshop on Advances in Sensors and Interfaces, June 26-27, 2007 Bari, Italy, IEEE , 2007, p. 1-4Conference paper (Other academic)
    Abstract [en]

         Gold nanoparticles (Au-NPs) have been synthesised using a sacrificial anode electrolysis in the presence of tetra-alkyl-ammonium halides, employed as cationic stabilizers. Catalytic NPs have been then deposited on top of Field Effect (FE) gas sensing devices and subjected to mild annealing procedures. Transmission Electron Microscopy (TEM) shows that the NP average core diameter is around 5 nm. X-Ray Photoelectron Spectroscopy (XPS) and Scanning Electron Microscopy (SEM) have been applied to the surface characterization of the annealed NP films used as active sensing layers. Morphological and spectroscopic results demonstrate that the annealed inorganic nano-clusters are finely dispersed and maintain a metallic oxidation state. Au-NPs can be proficiently employed as gate material in Si-Field Effect Gas Sensors. Preliminary results show interesting selectivity and sensitivity sensing features towards NOx detection.

  • 297.
    Immerstrand, Charlotte
    et al.
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Jager, Edwin W.H.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Magnusson, Karl-Eric
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Sundqvist, Tommy
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Lundström, Ingemar
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Peterson, K.H.
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Altered impedance during pigment aggregation in Xenopus laevis melanophores2003In: Medical and Biological Engineering and Computing, ISSN 0140-0118, E-ISSN 1741-0444, Vol. 41, no 3, p. 357-364Article in journal (Refereed)
    Abstract [en]

    Melanophores are dark-brown pigment cells located in the skin of amphibia, fish and many invertebrates. The skin colour of these organisms is regulated by the translocation of pigment organelles, and the pigment distribution can be altered by external stimuli. The ability to change colour in response to stimuli makes these cells of interest for biosensing applications. It was investigated whether pigment aggregation in Xenopus laevis melanophores can be detected by impedance measurements performed in transparent microvials. The results show that cell attachment, cell spreading and pigment aggregation all resulted in impedance changes, seen particularly at the highest frequency tested (10 kHz). The mechanisms behind the impedance changes were investigated by the addition of latrunculin or melatonin, both of which cause pigment aggregation. The latrunculin-induced aggregation was associated with cell area decrease and filamentous actin (F-actin) breakdown, processes that can influence the impedance. Lack of F-actin breakdown and an increase in cell area during melatonin-induced aggregation suggest that some other intracellular process also contributes to the impedance decrease seen for melatonin. It was shown that impedance measurements reflect not only cell attachment and cell spreading, but also intracellular events.

  • 298.
    Inganäs, Olle
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Berggren, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Andersson, Mats R.
    Chalmers Tekniska Högskola.
    Gustafsson, Göran
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Hjertberg, T.
    Chalmers Tekniska Högskola.
    Wennerström, O.
    Chalmers Tekniska Högskola.
    Dyreklev, Peter
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Granström, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Thiophene polymers in light emitting diodes: Making multicolour devices1995In: Synthetic metals, ISSN 0379-6779, E-ISSN 1879-3290, Vol. 71, no 1-3, p. 2121-2124Article in journal (Refereed)
    Abstract [en]

    We can control the bandgap of thiophene polymers over 2 eV by choosing the nature, position and regularity of side chain substitutions. Electroluminescence from these polymers cover the full visible spectrum, from the blue into the near infra-red. Blends of these polymer materials allow us to construct voltage controlled variable colour light sources. A newly developed transfer technique allow us to mount thin oriented films of the polymers in polymer LEDs to obtain polarised light sources giving polarisation anisotropys of up to 3. Sub-lambda light sources have been constructed from these polymer materials using nanometer polymer electrodes.

  • 299.
    Inganäs, Olle
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Granlund, T
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Theander, M
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Berggren, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Andersson, MR
    Chalmers Tekniska Högskola.
    Ruseckas, A
    Lunds universitet.
    Sundström, V
    Lunds universitet.
    Optical emission from confined poly(thiophene) chains1998In: Optical materials (Amsterdam), ISSN 0925-3467, E-ISSN 1873-1252, Vol. 9, no 1-4, p. 104-108Article in journal (Refereed)
    Abstract [en]

    We discuss the stages of the luminescence processes in substituted and soluble poly(thiophenes), using results from determinations of absolute quantum yields of photoluminescence, fast pump-probe experiments and microcavity devices. Enhancement of the quantum yield of photoluminescence, with poly(thiophenes) in the solid state, call be obtained by dispersing the conjugated chain in a molecularly dispersed polymer blend, or by adding side chains designed for forcing the conjugated main chains apart. At the wavelength of stimulated emission, we observe a narrow bandwidth emission in the high-Q one-dimensional microcavity devices prepared by sandwiching two dielectric mirrors around a thin polymer film, A strong enhancement of the power efficiency is observed at a pump power of 1 mu W/cm(2), but does not conclusively show lasing characteristics. (C) 1998 Elsevier Science B.V.

  • 300.
    Inoue, Hirofumi
    et al.
    Kyushu University, Fukuoka.
    Andersson, Mike
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics . Linköping University, The Institute of Technology.
    Yuasa, M
    Kyushu University, Fukuoka.
    Kida, T
    Kyushu University, Fukuoka.
    Lloyd Spetz, Anita
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics . Linköping University, The Institute of Technology.
    Shimanoe, Kengo
    Kyushu University, Fukuoka.
    Capacitor type CO2 gas sensor combined MISiC and solid electrolyte2010In: IMCS13, 2010, p. 235-Conference paper (Refereed)
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