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Imaging surface plasmon resonanceAndersson, Olof January 2008 (has links)
The central theme of this thesis is the use of imaging Surface Plasmon Resonance (iSPR) as a tool in the characterization of surfaces with laterally varying properties. Within the scope of this work, an instrument for iSPR analysis was designed and built. SPR is a very sensitive technique for monitoring changes in optical properties in the immediate vicinity of a sensor surface, which is very useful in biosensing and surface science research. We have employed SPR in the Kretschmann configuration, wherein surface plasmons are excited by means of an evanescent field arising from total internal reflection from the backside of the sensor surface. In iSPR, the signal is the reflectivity of TM-polarized light which is measured using an imaging detector, typically a CCD camera. Advantages of this technique include extreme surface sensitivity and, because detection is done from the backside, compatibility with complex samples. In addition, SPR is a non-labeling technique, and in imaging mode, a lateral resolution in the µm range can be attained. The imaging SPR instrument could be operated in either wavelength interrogation mode or in intensity mode. In the former case, the objective is to find the SPR wave-length, λSPR, which is the wavelength at which the reflected intensity is at a minimum. In intensity mode, a snapshot of the intensity reflectance is taken at a fixed wavelength hand incidence angle. In biosensor science, the use of an imaging technique offers a major advantage by enabling parallelization and thereby increasing throughput. We have, for example, used iSPR in biochemical interaction analysis to monitor immobilization and specific binding to protein and synthetic polypeptide micro arrays. The primary interest has been the study of soft matter surfaces that possess properties interesting in the field of biomimetics or for applications in biosensing. Specifically, the surfaces studied in this thesis include patterned self-assembled monolayers of thiolates on gold, a graft polymerized poly(ethylene glycol) (PEG) based hydrogel, a dextran hydrogel, and a polyelectrolyte charge gradient. Our results show that the PEG-based hydrogel is very well suited for use as a platform in protein immobilization in an array format, owing to the very low unspecific binding. In addition, well defined microarray templates were designed by patterning of hydrophobic barriers on dextran and monolayer surfaces. A polypeptide affinity microarray was further designed and immobilized on such a patterned monolayer substrate, in order to demonstrate the potential of analyte quantification with high sensitivity over a large dynamic range. Furthermore, iSPR was combined with electrochemistry to enable laterally resolved studies of electrochemical surface reactions. Using this combination, the electrochemical properties of surfaces patterned with self assembled monolayers can be studied in parallel, with a spatial resolution in the µm regime. We have also employed electrochemistry and iSPR for the investigation of potential and current density gradients on bipolar electrodes. The imaging SPR instrument could be operated in either wavelength interrogation mode or in intensity mode. In the former case, the objective is to find the SPR wave-length, λSPR, which is the wavelength at which the reflected intensity is at a minimum. In intensity mode, a snapshot of the intensity reflectance is taken at a fixed wavelength hand incidence angle.In biosensor science, the use of an imaging technique offers a major advantage by enabling parallelization and thereby increasing throughput. We have, for example, used iSPR in biochemical interaction analysis to monitor immobilization and specific binding to protein and synthetic polypeptide micro arrays. The primary interest has been the study of soft matter surfaces that possess properties interesting in the field of biomimetics or for applications in biosensing. Specifically, the surfaces studied in this thesis include patterned self-assembled monolayers of thiolates on gold, a graft polymerized poly(ethylene glycol) (PEG) based hydrogel, a dextran hydrogel, and a polyelectrolyte charge gradient. Our results show that the PEG-based hydrogel is very well suited for use as a platform in protein immobilization in an array format, owing to the very low unspecific binding. In addition, well defined microarray templates were designed by patterning of hydrophobic barriers on dextran and monolayer surfaces. A polypeptide affinity microarray was further designed and immobilized on such a patterned monolayer substrate, in order to demonstrate the potential of analyte quantification with high sensitivity over a large dynamic range.Furthermore, iSPR was combined with electrochemistry to enable laterally resolved studies of electrochemical surface reactions. Using this combination, the electrochemical properties of surfaces patterned with self assembled monolayers can be studied in parallel, with a spatial resolution in the µm regime. We have also employed electrochemistry and iSPR for the investigation of potential and current density gradients on bipolar electrodes.
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Novel Route of Oxynitride Glass Synthesis and Characterisation of Glasses in the Ln-Si-O-N and Ln-Si-Al-O-N SystemsHakeem, Abbas Saeed January 2007 (has links)
<p>The present work has been primarily focused on the glass forming region in the La-Si-O-N system, and attempts have been made to find glass forming regions by adopting a new synthesis route to produce glasses in oxynitride system. This goal can be attained by adding a network modifier in its metallic form instead of as an oxide. In this kind of synthesis, the metallic modifier reacts with nitrogen, which gives a strongly exothermic reaction at particular temperature. The resulting sudden increase in the temperature of the system enables the mixture to react with other components at an early stage of the synthesis. This also provides a high degree of mixing in the melt, and results in larger glass forming regions than reported until now (Figure A shows La from 30 to 62 e/o and nitrogen from 9 of 68 e/o in the La-Si-O-N system). The better property values (Tg-Tc, hardness and refractive index) were achieved over the whole compositional range in the systems.</p><p>Similarly, glasses containing Al were prepared in the Ln-Si-Al-O-N system, where Ln = La, Sm, Gd, Ho, Dy, and in the Ln-Si-O-N system, with Ln = Pr, Sm, Gd, Dy. Both systems were examined to study the properties at various nitrogen contents, which can be as high as 70 e/o. Glasses were prepared from one particular glass composition in the Pr-Si-O-N system by replacing Pr with various other La components, in order to study the effect of lanthanide substitution on the properties.</p><p>Figure A. The solid line encloses the glass forming region in the La-Si-O-N system, as determined in the present work. The dotted line represent the glass forming region according to the literature; details are given in figure 11.</p><p>A new synthesis route has extended the glass forming region, allowing a detailed study of properties such as hardness, glass transition temperature (Tg), glass crystallization temperature (Tc), density and refractive index. Comprehensive studies of properties may give better understanding of the glass structure. The glass transition temperatures range from 950 to 1100°C, and crystallization temperatures from 1050 to 1250°C; the hardness can be as high as 12 GPa and the refractive index attains the value 2.3 in the La-Si-O-N system. Hardness and refractive index were measured in both glass systems (Ln-Si-O-N and Ln-Si-Al-O-N) when substituting cations, and a detailed study of replacing La with Pr in the La-Si-O-N system yielded substantial effects on the properties of the glasses.</p><p>Higher values of hardness were found: ~13 GPa when applying load of one kg, and an increase with decreasing cation radius was noted in both the Ln-Si-O-N and the Ln-Si-Al-O-N system, containing of 63 and 61 e/o nitrogen, respectively. The hardness increases as the lanthanide ionic radius decreases, and becomes as high as 13.5 GPa in the Dy-Si-O-N system, and the refractive index is 2.3 in the La-Si-O-N system. A linear increase in the properties Tg-Tc, hardness and refractive index with increasing Pr content was found in the Pr-(La)-Si-O-N system.</p>
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Från kärna till ölWinge, Emelie January 2007 (has links)
<p>Korn, vatten, humle och jäst är råvarorna för att göra ett gott öl. Innan man kan använda kornet blöts det i vatten och får ligga under värme för att gro. Detta kallas mältning och enzymet för att ombilda stärkelse i kornet till socker bildas. </p><p>I kölnan torkas malten (kornet) med varmluft och transporteras till bryggeriet för bryggning. Malten krossas och blandas med vatten till en mäsk som värms upp. Detta är mäskningen där enzymet ombildar stärkelse till socker. </p><p>När man silat blandningen, som nu kallas vört, kokas den kraftigt tillsammans med humlen som ger ölet smak. Sedan silar man bort humleresterna.</p><p>Vörten går vidare till jäsning där de förjäsbara sockerarterna omvandlas till alkohol och när ölet jäst färdigt måste det lagras en tid, beroende på doft och smak.</p><p>Slutligen filtrerar man ölet och tappar det på flaskor, burkar eller fat. Samtidigt pastöriserar man ölet dvs. tar kål på jästresterna och andra organismer som kan skada ölet.</p>
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Comparison of flavour compounds in juices from different blackcurrant varietiesOhlsson, Anna January 2009 (has links)
No description available.
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New Techniques for Sample Preparation in Analytical ChemistryAltun, Zeki January 2005 (has links)
<p>Sample preparation is often a bottleneck in systems for chemical analysis. The aim of this work was to investigate and develop new techniques to address some of the shortcomings of current sample preparation methods. The goal has been to provide full automation, on-line coupling to detection systems, short sample preparation times and high-throughput.</p><p>A new technique for sample preparation that can be connected on-line to liquid chromatography (LC) and gas chromatography (GC) has been developed. Microextraction in packed syringe (MEPS) is a new solid-phase extraction (SPE) technique that is miniaturized and can be fully automated. In MEPS approximately 1 mg of sorbent material is inserted into a gas tight syringe (100-250 μL) as a plug. Sample preparation takes place on the packed bed. Evaluation of the technique was done by the determination of local anaesthetics in human plasma samples using MEPS on-line with LC and tandem mass spectrometry (MS-MS). MEPS connected to an autosampler was fully automated and clean-up of the samples took one minute. In addition, in the case of plasma samples the same plug of sorbent could be used for about 100 extractions before it was discarded.</p><p>A further aim of this work was to increase sample preparation throughput. To do that disposable pipette tips were packed with a plug of porous polymer monoliths as sample adsorbent and were then used in connection with 96-well plates and LC-MS-MS. When roscovitine in human plasma and water samples was used as model substance, a 96-plate was handled in two minutes.</p>
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Single-chain antibody construction and functional mapping of the monoclonal antibody TS1 : Its interaction with the antigen and the anti-idiotypeHolm, Patrik January 2005 (has links)
<p>The aims of this study are to synthesize and produce a single-chain antibody (scFv) of the anti-cytokeratin 8 monoclonal IgG antibody TS1 and to functionally map amino acid residues important for the interaction with its antigen and the anti-idiotypic antibody TS1. The TS1 antibody has been shown to be effective in binding cytokeratin 8 (CK8) expressed in tumors in vivo and is proposed to be useful in immunotargeting and/or immunotherapy. The anti-idiotypic antibody TS1 can be used to regulate the tumor:non-tumor ratio. Mutagenesis of certain amino acid residues can be used to alter the affinity to improve the tumor:non-tumor ratio further.</p><p>In the present study, the TS1 IgG was chemically modified to specify groups of residues important for interaction with both CK8 and TS1. If important residues were found in the CDRs, they were mutated in the TS1 scFv construct and the effect was studied using ELISA.</p><p>The main conclusions drawn from this study are that the important amino acid residues in TS1 for the interaction with both CK8 and TS1 are mainly tyrosines, charged residues and a tryptophan. A central interacting interface was identified with the somewhat unusual participation of residues in the CDR 2 of the light chain. Mutations which resulted in increased affinity to both CK8 and TS1 were also identified.</p>
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New Techniques for Sample Preparation in Analytical ChemistryAltun, Zeki January 2005 (has links)
Sample preparation is often a bottleneck in systems for chemical analysis. The aim of this work was to investigate and develop new techniques to address some of the shortcomings of current sample preparation methods. The goal has been to provide full automation, on-line coupling to detection systems, short sample preparation times and high-throughput. A new technique for sample preparation that can be connected on-line to liquid chromatography (LC) and gas chromatography (GC) has been developed. Microextraction in packed syringe (MEPS) is a new solid-phase extraction (SPE) technique that is miniaturized and can be fully automated. In MEPS approximately 1 mg of sorbent material is inserted into a gas tight syringe (100-250 μL) as a plug. Sample preparation takes place on the packed bed. Evaluation of the technique was done by the determination of local anaesthetics in human plasma samples using MEPS on-line with LC and tandem mass spectrometry (MS-MS). MEPS connected to an autosampler was fully automated and clean-up of the samples took one minute. In addition, in the case of plasma samples the same plug of sorbent could be used for about 100 extractions before it was discarded. A further aim of this work was to increase sample preparation throughput. To do that disposable pipette tips were packed with a plug of porous polymer monoliths as sample adsorbent and were then used in connection with 96-well plates and LC-MS-MS. When roscovitine in human plasma and water samples was used as model substance, a 96-plate was handled in two minutes.
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Nanoparticles in capillary electrophoresis : what are the benefits?Malmström, David January 2011 (has links)
Capillary electrophoresis is a technique that separate compounds based on charge and size. During the last two decades capillary electrophoresis (CE) and mass spectrometry (MS) has gained in interest, become more robust to use and able to separate neutral analytes. The separation of neutral analytes was first achieved with packed columns, but several disadvantages can be obtained with a stationary phase and the method of packing capillaries. Therefore, pseudostationary phases became a good alternative. The risk of clogging, memory effects and lower efficiency could be minimized with pseudophases. However, since mass spectrometry has become the most important analytical detector, and play a key role in the search for biomarkers in clinical applications, it is important that CE can successfully be combined with MS. To obtain this hyphenation several types of interfaces for the vital ion source exist. In paper I an atmospheric pressure photoionization interface was investigated in order to accomplish an improved detection sensitivity. The knowledge attained with this type of interface could then be transferred to the one used in paper II, the electrospray ionization interface (ESI), where the use of a MS friendly nanoparticle based pseudostationary phase was investigated. Both studies showed that it is still possible to improve the separation technique and modify the ion source in order to improve the detection sensitivity for capillary electrophoresis hyphenated with mass spectrometry.
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Studies of Oxygen Deficient Complex Cobaltates with Perovskite Related StructuresLindberg, Fredrik January 2006 (has links)
The present thesis deals with the investigation of some perovskite related complex cobaltates. The phases Sr2Co2-xGaxO5 (0.3 ≤ x ≤ 0.7), Sr2Co2-xAlxO5 (0.3 ≤ x ≤ 0.5), Sr1-xBixCoO3-y (0.1 ≤ x ≤ 0.2), Sr0.75Y0.25Co1-xGaxO2.625 (0.125 ≤ x ≤ 0.375) and Sr0.75Y0.25Co1-xFexO2.625+δ (0.125 ≤ x ≤ 0.625) were synthesised and characterised. All these compounds crystallises with similar structures, they are all composed by altering layers of octahedra and tetrahedra although in the two former, the tetrahedra are organised in chains (the Brownmillerite structure), while in the latter three the tetrahedra arranges as segregated Co4O12 units (the 314 type structure). The techniques X-ray and neutron diffraction, transmission electron microscopy, thermal analysis and magnetic measurements were used to track structural and important physical properties.
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Novel Route of Oxynitride Glass Synthesis and Characterisation of Glasses in the Ln-Si-O-N and Ln-Si-Al-O-N SystemsHakeem, Abbas Saeed January 2007 (has links)
The present work has been primarily focused on the glass forming region in the La-Si-O-N system, and attempts have been made to find glass forming regions by adopting a new synthesis route to produce glasses in oxynitride system. This goal can be attained by adding a network modifier in its metallic form instead of as an oxide. In this kind of synthesis, the metallic modifier reacts with nitrogen, which gives a strongly exothermic reaction at particular temperature. The resulting sudden increase in the temperature of the system enables the mixture to react with other components at an early stage of the synthesis. This also provides a high degree of mixing in the melt, and results in larger glass forming regions than reported until now (Figure A shows La from 30 to 62 e/o and nitrogen from 9 of 68 e/o in the La-Si-O-N system). The better property values (Tg-Tc, hardness and refractive index) were achieved over the whole compositional range in the systems. Similarly, glasses containing Al were prepared in the Ln-Si-Al-O-N system, where Ln = La, Sm, Gd, Ho, Dy, and in the Ln-Si-O-N system, with Ln = Pr, Sm, Gd, Dy. Both systems were examined to study the properties at various nitrogen contents, which can be as high as 70 e/o. Glasses were prepared from one particular glass composition in the Pr-Si-O-N system by replacing Pr with various other La components, in order to study the effect of lanthanide substitution on the properties. Figure A. The solid line encloses the glass forming region in the La-Si-O-N system, as determined in the present work. The dotted line represent the glass forming region according to the literature; details are given in figure 11. A new synthesis route has extended the glass forming region, allowing a detailed study of properties such as hardness, glass transition temperature (Tg), glass crystallization temperature (Tc), density and refractive index. Comprehensive studies of properties may give better understanding of the glass structure. The glass transition temperatures range from 950 to 1100°C, and crystallization temperatures from 1050 to 1250°C; the hardness can be as high as 12 GPa and the refractive index attains the value 2.3 in the La-Si-O-N system. Hardness and refractive index were measured in both glass systems (Ln-Si-O-N and Ln-Si-Al-O-N) when substituting cations, and a detailed study of replacing La with Pr in the La-Si-O-N system yielded substantial effects on the properties of the glasses. Higher values of hardness were found: ~13 GPa when applying load of one kg, and an increase with decreasing cation radius was noted in both the Ln-Si-O-N and the Ln-Si-Al-O-N system, containing of 63 and 61 e/o nitrogen, respectively. The hardness increases as the lanthanide ionic radius decreases, and becomes as high as 13.5 GPa in the Dy-Si-O-N system, and the refractive index is 2.3 in the La-Si-O-N system. A linear increase in the properties Tg-Tc, hardness and refractive index with increasing Pr content was found in the Pr-(La)-Si-O-N system.
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