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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
91

Fluorescent Probes to Investigate Homologous Recombination Dynamics

Davenport, Eric Parker 01 May 2016 (has links)
There are multiple mechanisms by which DNA can become damaged. Such damage must be repaired for the cell to avoid ill-health consequences. Homologous recombination (HR) is a means of repairing one specific type of damage, a double-strand break (DSB). This complex pathway includes the Rad51-DNA nucleoprotein filament as its primary machinery. Current methodology for studying HR proteins includes the use of fluorescently labeled DNA to probe for HR dynamics. This technique limits the number of proteins that can be involved in experimentation, and often only works as an end reporter. The work here aims at improving upon standard techniques by creating two fluorescent protein probes. The first probe was developed by directly attaching a fluorophore to Saccharomyces cerevisiae Rad51 with the use of click chemistry and the incorporation of unnatural amino acids. This probe could function as a primary reporter on the formation and dissociation of the Rad51-DNA filament in the presence of pro- and anti- HR mediator proteins. The second probe was created by labeling the exterior cysteine residues of Plasmodium falciparum single strand DNA binding protein (SSB) with a fluorophore via maleimide chemistry. This probe acts as a secondary reporter for HR dynamics by signaling for when free single stranded DNA (ssDNA) is available.
92

The myth of Total Incorporation? : The case-study of French migrants in Sweden

Geiger, Nicolas January 2010 (has links)
<p>The myth of total incorporation ? The study-case of French immigrants in Sweden.</p><p>French individuals cannot be gathered into a « specific » migration pattern, and they are all affected by the process of incorporation into the receiving country. The concept of incorporation refers to the linkages between migrants and institutions of the receiving country as well as the receiving society. French migrants are the studied population because of their particular position in Sweden, perceived as « incorporated » and « privileged » populations. The focus is made on the incorporation process, deconstructed into four key points of analysis such as the working conditions, language, housing conditions and finally the culture. Linking theories to the reality of incorporation is possible through this empirical research, where the first part is dealing with the theories and concepts and the second part relates these concepts and theories with the reality of French migrants via interviews.The outcomes are showing that incorporation is a personal process that cannot be forced, and the tendencies are that migrants unconsciously adopt points from assimilation and integration policies, challenging the myth of total incorporation which classically defines population as incorporated/non-incorporated without taking in account that migrants can be incorporated/non-incorporated according to specific points.</p><p>Key words: Incorporation, Assimilation, Integration, Sweden, intra-European migration, international migration.</p>
93

Étude des transferts du tritium atmosphérique chez la laitue: étude cinétique, état d'équilibre et intégration du tritium sous forme organique lors d'une exposition atmosphérique continue

Boyer, Cécile 30 November 2009 (has links) (PDF)
Ce travail de thèse a concerné l'étude des phénomènes d'absorption et d'incorporation sous forme organique du tritium dans un végétal de consommation courante, la laitue (Lactuca sativa L.), en réponse à une exposition atmosphérique. Il apparaît que la voie foliaire joue un rôle primordial dans l'absorption du tritium au sein de l'eau tissulaire des plants. Quels que soient le stade de développement des plants et les conditions d'éclairement, le temps nécessaire pour atteindre l'équilibre des concentrations dans l'eau libre et dans la vapeur d'eau de l'air est de plusieurs heures ; le rapport des concentrations est alors de l'ordre de 0,4. Dans le sol, le temps de mise à l'équilibre dépasse généralement 24 heures ; le rapport des concentrations à l'état stationnaire est compris entre 0,01 et 0,26. Le taux d'incorporation du tritium de l'eau tissulaire sous forme organique est de l'ordre de 0,13 à 0,16 % h-1 en moyenne sur la durée de vie entière de la plante. Cependant, l'incorporation de l'OBT dépend fortement du stade de développement du végétal. La période de plus forte intégration du tritium sous forme organique correspond à la phase de croissance exponentielle des végétaux. Le dépôt et la diffusion du tritium dans le sol entrainent des activités significatives dans la fraction organique du sol. Les résultats obtenus vont globalement dans le sens d'une mise à l'équilibre des concentrations du tritium dans le végétal (eau libre et tritium organique) avec celles de l'environnement (atmosphère, sol). Certaines expériences ont néanmoins révélé des activités OBT anormalement élevées dans les laitues au regard des niveaux d'exposition et posent la question d'un possible phénomène d'accumulation locale du tritium dans la matière organique pour des conditions particulières d'exposition.
94

SiC Homoepitaxial Growth at High Rate by Chloride-based CVD

Lin, Yuan-Chih January 2010 (has links)
<p>SiC is an attractive material since it has remarkable properties. For several years efforts have been put primarily in electronic applications. High power and high frequency devices can be fabricated on SiC due to its wide band gap, high breakdown field and high thermal conductivity. SiC devices can be used in harsh environment since its operation temperature is significantly high (about 1200 ). SiC bulk growth has been improved by seeded physical vapour transport (PVT) during last decades. However, the quality and doping concentration of SiC bulk are not good enough to be used as an active layer for devices. SiC epilayer growth by chemical vapour deposition (CVD) was established in the last three decades. Only about 5 µm/h growth rate is achieved by CVD with a standard process. Long deposition time is required to grow ≥100µm thick epilayer for high voltage devices. The main problem in standard CVD is the formation of silicon (Si) droplets due to supersaturation of Si-species on the growth surface or in the gas-phase, which is detrimental for devices performance. To solve the problem of Si-droplets, chloride-based CVD was introduced. Chlorinated species can dissolve the silicon aggregates through the formation of strong bonds to silicon species compared to Si-Si bonds. Typical chlorinated precursors are hydrogen chloride (HCl) and methyltrichlorosilane (MTS). In this thesis study, HCl was mainly used as chlorinated precursors. Distinct chlorinated precursors result in different chemical reactions which affect the epilayer growth appreciably. The Cl/Si ratio, which is the ratio of the amount of chlorinated precursors to silicon precursors, is a very critical growth parameter for morphology, growth rate and background doping concentration. The C/Si ratio and Si/H<sub>2</sub> ratio also affect the epilayer growth appreciably. Besides, growth temperature, growth pressure and temperature ramp up condition are other important growth parameters. In the CVD reaction chamber, the temperature profile and gas species distribution are not uniform along the whole susceptor length, which leads to different thickness of epilayer, morphology and doping concentration at different area of the reaction chamber. The polarity and off-angle of substrates can bring about complete different grown epilayers. Epitaxial defects are mainly replicated from the substrate. Therefore, the quality of substrates is very important as well. Deep energy levels can be introduced by adding transition metal such as vanadium (V), chromium (Cr) or tungsten (W). There are some limits which are needed to be overcome for a complete development of SiC. 4” SiC wafers are commercially available on the market, larger diameter would be very useful for the industrial development of SiC. High growth rate and good quality with controlled uniformity are desired for electronic applications. In this thesis, the influences of growth parameters such as C/Si and Cl/Si ratios, comparison between different precursors, growth condition in different areas of reaction chamber and effects of substrate polarity are discussed. Intentional incorporation of tungsten atoms is investigated by deep-level transient spectroscopy measurement and thermodynamic analysis.</p>
95

Consumer perceptions on the incorporation of established brands : The acquisition of Body Shop by L’Oréal

Robens, Catherine January 2007 (has links)
<p>This thesis aims at investigating consumers’ perceptions on the incorporation of an established brand and how the general attitude and buying behaviour is altered in the course of an acquisition. The combination of two or more brands in a newly formed conglomerate implies a combination of values, principles and associations that might affect a company’s appeal. Therefore, underlying reasons for M&As will be elaborated upon as well as branding concepts based on brand image, loyalty and reputation in order to bridge the two theoretical areas with a case study. The acquisition of Body Shop International by L’Oréal represents the practical case, which will be analysed in reference to consumers’ reactions towards it. Quantitative consumer questionnaires will be conducted in order to collect representative data on consumers’ perceptions and associations of the brand Body Shop. Moreover, an expert interview with a Body Shop representative will be executed in order to add the company’s perspective. By analysing the results of the questionnaire, the thesis reveals an observable trend towards a correlation of the awareness of the acquisition and a negative shift in customer perception. The buying behaviour is however not found to be influenced by the combination of the two firms. In conclusion, it can be stated that the need for pre-acquisition analysis regarding strategic fit and compatibility of values and associations is assured. The study clearly identifies that brand dilution is a possible threat for established brands and implies the risk of lost credibility and loyalty.</p>
96

The myth of Total Incorporation? : The case-study of French migrants in Sweden

Geiger, Nicolas January 2010 (has links)
The myth of total incorporation ? The study-case of French immigrants in Sweden. French individuals cannot be gathered into a « specific » migration pattern, and they are all affected by the process of incorporation into the receiving country. The concept of incorporation refers to the linkages between migrants and institutions of the receiving country as well as the receiving society. French migrants are the studied population because of their particular position in Sweden, perceived as « incorporated » and « privileged » populations. The focus is made on the incorporation process, deconstructed into four key points of analysis such as the working conditions, language, housing conditions and finally the culture. Linking theories to the reality of incorporation is possible through this empirical research, where the first part is dealing with the theories and concepts and the second part relates these concepts and theories with the reality of French migrants via interviews.The outcomes are showing that incorporation is a personal process that cannot be forced, and the tendencies are that migrants unconsciously adopt points from assimilation and integration policies, challenging the myth of total incorporation which classically defines population as incorporated/non-incorporated without taking in account that migrants can be incorporated/non-incorporated according to specific points. Key words: Incorporation, Assimilation, Integration, Sweden, intra-European migration, international migration.
97

SiC Homoepitaxial Growth at High Rate by Chloride-based CVD

Lin, Yuan-Chih January 2010 (has links)
SiC is an attractive material since it has remarkable properties. For several years efforts have been put primarily in electronic applications. High power and high frequency devices can be fabricated on SiC due to its wide band gap, high breakdown field and high thermal conductivity. SiC devices can be used in harsh environment since its operation temperature is significantly high (about 1200 ). SiC bulk growth has been improved by seeded physical vapour transport (PVT) during last decades. However, the quality and doping concentration of SiC bulk are not good enough to be used as an active layer for devices. SiC epilayer growth by chemical vapour deposition (CVD) was established in the last three decades. Only about 5 µm/h growth rate is achieved by CVD with a standard process. Long deposition time is required to grow ≥100µm thick epilayer for high voltage devices. The main problem in standard CVD is the formation of silicon (Si) droplets due to supersaturation of Si-species on the growth surface or in the gas-phase, which is detrimental for devices performance. To solve the problem of Si-droplets, chloride-based CVD was introduced. Chlorinated species can dissolve the silicon aggregates through the formation of strong bonds to silicon species compared to Si-Si bonds. Typical chlorinated precursors are hydrogen chloride (HCl) and methyltrichlorosilane (MTS). In this thesis study, HCl was mainly used as chlorinated precursors. Distinct chlorinated precursors result in different chemical reactions which affect the epilayer growth appreciably. The Cl/Si ratio, which is the ratio of the amount of chlorinated precursors to silicon precursors, is a very critical growth parameter for morphology, growth rate and background doping concentration. The C/Si ratio and Si/H2 ratio also affect the epilayer growth appreciably. Besides, growth temperature, growth pressure and temperature ramp up condition are other important growth parameters. In the CVD reaction chamber, the temperature profile and gas species distribution are not uniform along the whole susceptor length, which leads to different thickness of epilayer, morphology and doping concentration at different area of the reaction chamber. The polarity and off-angle of substrates can bring about complete different grown epilayers. Epitaxial defects are mainly replicated from the substrate. Therefore, the quality of substrates is very important as well. Deep energy levels can be introduced by adding transition metal such as vanadium (V), chromium (Cr) or tungsten (W). There are some limits which are needed to be overcome for a complete development of SiC. 4” SiC wafers are commercially available on the market, larger diameter would be very useful for the industrial development of SiC. High growth rate and good quality with controlled uniformity are desired for electronic applications. In this thesis, the influences of growth parameters such as C/Si and Cl/Si ratios, comparison between different precursors, growth condition in different areas of reaction chamber and effects of substrate polarity are discussed. Intentional incorporation of tungsten atoms is investigated by deep-level transient spectroscopy measurement and thermodynamic analysis.
98

Consumer perceptions on the incorporation of established brands : The acquisition of Body Shop by L’Oréal

Robens, Catherine January 2007 (has links)
This thesis aims at investigating consumers’ perceptions on the incorporation of an established brand and how the general attitude and buying behaviour is altered in the course of an acquisition. The combination of two or more brands in a newly formed conglomerate implies a combination of values, principles and associations that might affect a company’s appeal. Therefore, underlying reasons for M&amp;As will be elaborated upon as well as branding concepts based on brand image, loyalty and reputation in order to bridge the two theoretical areas with a case study. The acquisition of Body Shop International by L’Oréal represents the practical case, which will be analysed in reference to consumers’ reactions towards it. Quantitative consumer questionnaires will be conducted in order to collect representative data on consumers’ perceptions and associations of the brand Body Shop. Moreover, an expert interview with a Body Shop representative will be executed in order to add the company’s perspective. By analysing the results of the questionnaire, the thesis reveals an observable trend towards a correlation of the awareness of the acquisition and a negative shift in customer perception. The buying behaviour is however not found to be influenced by the combination of the two firms. In conclusion, it can be stated that the need for pre-acquisition analysis regarding strategic fit and compatibility of values and associations is assured. The study clearly identifies that brand dilution is a possible threat for established brands and implies the risk of lost credibility and loyalty.
99

Design de nouveaux catalyseurs par incorporation d'hétéropolyanion dans une matrice mésostructurée

Colbeau-Justin, Frédéric 24 September 2012 (has links) (PDF)
Cette étude décrit le développement de nouveaux catalyseurs d'hydrotraitement (HDT) et d'hydrocraquage (HCK) par couplage de la chimie sol gel au procédé aérosol. Les matériaux synthétisés sont des silices et des aluminosilicates (rapport molaire Si/Al = 12) à porosité mésostructurée, dans lesquels une phase oxométallique composée de cobalt et de molybdène est incorporée. Les synthèses ont été effectuées à partir de précurseurs inorganiques (tétraéthylorthosilicate et chlorure d'aluminium), de tensioactif Pluronic P123 ([EO]30-[PO]70-[EO]30), d'hétéropolyanions (HPA) de molybdène, de structure Keggin ([PMo12O40]3-) ou de structure Strandberg ([P2Mo5O23]6-), ainsi que d'hydroxyde de cobalt (Co(OH)2). La teneur en molybdène, la nature de l'HPA initialement utilisé et la température de calcination visant libérer la porosité, sont des paramètres qui influencent grandement la structure des matériaux. Ainsi, l'étude des propriétés texturales et structurales de la matrice par volumétrie à l'azote, SAXS, MET, ainsi que l'étude de la phase oxométallique par RMN 31P, IRTF et Raman a permis de proposer une modélisation structurale des matériaux. La structure, la dispersion ainsi que la localisation de la phase oxométallique au sein de la matrice poreuse mésostructurée est également discutée en détail. Les matériaux ont été étudiés par XPS et MET après sulfuration et les performances catalytiques en hydrogénation du toluène ont été testées. L'activité catalytique est dépendante de la morphologie des feuillets sulfure, cette dernière étant conditionnée par l'incorporation des précurseurs oxométallique dans une matrice mésostructurée
100

Growth and characterization of HfON thin films with the crystal structures of HfO2

Lü, Bo January 2011 (has links)
HfO2 is a popular replacement for SiO2 in modern CMOS technology. It is used as the gate dielectric layer isolating the transistor channel from the gate. For this application, certain material property demands need to be met, most importantly, a high static dielectric constant is desirable as this positively influences the effectiveness and reliability of the device. Previous theoretical calculations have found that this property varies with the crystal structure of HfO2; specifically, the tetragonal structure possesses the highest dielectric constant (~70 from theoretical calculations) out of all possible stable structures at atmospheric pressure, with the cubic phase a far second (~29, also calculated). Following the results from previous experimental work on the phase formation of sputtered HfO2, this study investigates the possibility of producing thin films of HfO2 with the cubic or tetragonal structure by the addition of nitrogen to a reactive sputtering process at various deposition temperatures. Also, a new physical vapor deposition method known as High Power Impulse Magnetron Sputtering (HiPIMS) is employed for its reported deposition stability in the transition zone of metal-oxide compounds and increased deposition rate. Structural characterization of the produced films shows that films deposited at room temperature with a low N content (~6 at%) are mainly composed of amorphous HfO2 with mixed crystallization into t-HfO2 and c-HfO2, while pure HfO2 is found to be composed of amorphous HfO2 with signs of crystallization into m-HfO2. At 400o C deposition temperature, the crystalline quality is enhanced and the structure of N incorporated HfO2 is found to be c-HfO2 only, due to further ordering of atoms in the crystal lattice. Optical and dielectric characterization revealed films with low N incorporation (&lt; 6 at%) to be insulating while these became conductive for higher N contents. For the insulating films, a trend of increasing static dielectric constant with increasing N incorporation is found.

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