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1
Bruce, Henrik. "Formulation of Model Problem for Chirality Induced Spin Selectivity Effect." Thesis, Uppsala universitet, Materialteori, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-414026.
Abstract:
Spin dependent electron transport in chiral molecules, the so-called chirality induced spin selectivity (CISS) effect, have attracted much attention over the past few years. Experimentally the spin polarization has been detected, and there is a theoretical consensus on the necessity of both spin-orbit coupling and geometrical helicity in order to get a non-vanishing spin polarization. Several model Hamiltonians has been proposed to describe the CISSS effect, and while they can yield spin polarization agreeing with the experimentally observed magnitudes, they are relying on unrealistic values of the spin orbit interaction parameters. In recent years the importance of electron correlation has been emphasized. Thus, this thesis presents the general theory on how to treat the CISS effect as a many body problem, taking electron correlation into account. The Hamiltonian modelling is described and one approach on how to treat the helical structure of the molecule and the spin-orbit coupling is presented. Building on this thesis, further studies will hopefully lead to a first principle understanding of the CISS effect.
2
Tieriekhov, Kostiantyn. "Applications non-conventionnelles de champs magnétiques à séparation chirale et aux systèmes électrochimiques dynamiques." Electronic Thesis or Diss., Bordeaux, 2023. http://www.theses.fr/2023BORD0502.
Abstract:
L’énantioséparation de précision est essentielle pour les industries pharmaceutiques et alimentaires. Les techniques conventionnelles de séparation chirale offrent un large éventail de méthodes, qui reposent toutes sur des sélecteurs chiraux - des phases stationnaires ou des molécules qui distinguent les énantiomères par une interaction stéréospécifique. Malgré le grand nombre de sélecteurs naturels et synthétiques actuellement utilisés, la demande croissante d’énantiopurité stimule la recherche de nouvelles méthodes polyvalentes.Le but de cette thèse est d'étudier des méthodes alternatives de séparation chirale impliquant l'application de champs magnétiques dans diverses configurations. Une idée est centrée sur le concept de vraie et fausse chiralité, introduit par L. Barron pour les systèmes dynamiques d'objets individuels et de grandeurs physiques vectorielles. Sa discussion indique explicitement que ni les champs magnétiques ni électriques statiques, ni aucune combinaison de ceux-ci, ne possèdent une véritable chiralité, la caractéristique requise pour induire une discrimination énantiomérique. Cependant, sa théorie suggère l’existence d’un analogue moléculaire de l’effet Faraday bien connu sous forme de l’application colinéaire d’un champ magnétique à un flux moléculaire.Alternativement, une configuration perpendiculaire au flux moléculaire impliquant un substrat ferromagnétique a démontré des interactions de spin énantiospécifiques, également connues sous le nom d'effet CISS. À cet égard, notre objectif principal était d’explorer une telle interaction dans des conditions dynamiques d’électrophorèse capillaire, qui permet une détection simple et rapide, tout en introduisant des substrats de Ni le long du flux de molécules et en appliquant un champ magnétique orthogonal.Enfin, la configuration orthogonale du champ magnétique a été exploitée pour étudier le comportement dynamique d'objets électropolarisés. Il a été démontré que la rotation présenté par différents objets sous l'effet magnétohydrodynamique induit par la force de Lorentz dépendent de la polarité du champ magnétique. Leur comportement dynamique en fonction du temps ressemble à celui de systèmes faussement chirauxHigh-purity enantioseparation is essential for the pharmaceutical and food industries. Conventional chiral separation techniques provide a wide range of methods, all of which rely on chiral selectors - stationary phases or molecules that discriminate enantiomers through stereospecific interaction. Despite the vast number of natural and synthetic selectors currently in use, the increasing demand for enantiopurity is driving research for new and versatile methods.The aim of this thesis is to investigate alternative methods of chiral separation that involve the application of magnetic fields in various configurations. One idea centers around the concept of true and false chirality, which was introduced by L. Barron for dynamic systems of individual objects and physical vector quantities. His discussion explicitly states that neither static magnetic nor electric fields, nor any combination of those, possess true chirality, the feature required to induce enantiomeric discimination. However, his theory suggests a molecular analog of the well-known Faraday effect based on the collinear application of magnetic field to a molecular flow.Alternatively, a perpendicular configuration with the molecular flow involving a ferromagnetic substrate has demonstrated enantiospecific spin interactions, otherwise known as the CISS effect. In this regard, our main objective was the further exploration of such interactions in dynamic conditions of capillary electrophoresis, which provides simple and fast detection, while introducing Ni substrates along the flow of molecules and applying an orthogonal magnetic field.Lastly, the orthogonal configuration of the magnetic field was exploited to study the dynamic behavior of electropolarized objects. The patterns of the resulting rotation, exhibited by different objects under the influence of a magnetohydrodynamic effect, originating from the induced Lorentz force, are shown to be dependent on magnetic field polarity. Their dynamic behavior as a function of time resembles those of falsely chiral systems
3
Stanley, Mishael. "Développement de Cellules Photovoltaiques à base de CIGS de haute performance sur substrats métalliques." Electronic Thesis or Diss., Paris Sciences et Lettres (ComUE), 2019. http://www.theses.fr/2019PSLEC023.
Abstract:
L’objectif de cette thèse est l’optimisation de cellules solaires à base de Cu(In,Ga)Se2 (CIGS) sur substrat métallique à très haut rendement (>20%). Les métaux ont généralement une meilleure tenue mécanique que le verre qui est un matériau fragile. Cela permet par exemple de réduire fortement leur épaisseur et d’obtenir des dispositifs photovoltaïques plus légers. De plus, si leur épaisseur est suffisamment réduite, ils deviennent conformables voire flexibles. Cependant, les substrats métalliques ont leurs propres inconvénients. Ils peuvent contenir des impuretés (ex : Fe) qui dégradent les propriétés électroniques du matériau absorbeur. De plus, leur coefficient de dilatation thermique n’est pas toujours adapté aux procédés d’élaboration à haute température du CIGS. Enfin les cellules CIGS déposées sur substrat verre bénéficient d’un apport de sodium, élément connu pour améliorer les propriétés du CIGS, et apporté par la diffusion de cet élément depuis le verre via le molybdène. L’objectif principal de cette thèse consiste à réaliser des cellules solaire à base de CIGS par la technique de coévaporation sur substrats métalliques ayant des performances les plus proches possibles des cellules sur substrats en verre sodocalcique (>20%). Les problématiques auxquelles cette thèse doit répondre sont le choix du substrat métallique, le blocage de la diffusion des impuretés contenues dans les substrats métalliques, l’assurance d’une adhésion forte au substrat, la réduction des contraintes résiduelles (permettant de garantir l’adhésion) et surtout l’optimisation de la couche de Mo adéquate permettant l’apport nécessaire d’élément alcalin (Na/K,…) pour un CIGS de haute performance et l’adaptation de l’absorbeur à ce type de substrat. En effet la qualité du CIGS sera fortement dépendante de la température de dépôt, de l’apport d’élément alcalin provenant du substrat et des gradients de composition In/Ga du contact arrière vers la surface du CIGS. Il est connu qu’il est nécessaire d’avoir un gradient de gallium dans la couche de CIGS afin d’obtenir des cellules à haut. Le dépôt de couches de CIGS par co-évaporation se fera par la méthode du « three-stage process ». Celle-ci consiste à déposer la couche en trois étapes bien définies. Il est important de bien maîtriser ce procédé afin de pouvoir obtenir un absorbeur de qualité pour les cellules solairesThe objective of this thesis is the optimization of solar cells based on Cu (In, Ga) Se 2 (CIGS) on high performance metal substrate (> 20%). Metals generally have better mechanical strength than glass which is a brittle material. This allows for example to significantly reduce their thickness and get lighter photovoltaic devices. Moreover, if their thickness is sufficiently reduced, they become conformable or flexible. However, the metal substrates have their own drawbacks. They may contain impurities (eg Fe) that degrade the electronic properties of the absorber material. Furthermore, their thermal expansion coefficient is not always suitable for methods of making high temperature CIGS. Finally CIGS cells on glass substrate have a sodium intake, known element for improving the properties of the CIGS, and brought by the spread of this element from the glass through the molybdenum. The main objective of this thesis is to make solar cells based on CIGS by co-evaporation technique on metal substrates having the closest possible performance of the cells on substrates of soda lime glass (> 20%). The problems that this thesis must meet are the choice of the metal substrate, blocking the diffusion of impurities in the metallic substrates, ensuring strong adhesion to the substrate, reducing residual stresses (to ensure adherence ) and especially the optimization of the Mo adequate layer allowing necessary intake of alkali metal element (Na / K, ...) for a high performance and adaptation CIGS absorber to this type of substrate. Indeed the quality of CIGS will be highly dependent on the deposition temperature of the intake of alkaline element from the substrate and composition gradients In / Ga the back contact to the surface of CIGS. It is known that it is necessary to have a gradient gallium in the CIGS layer in order to obtain cells high. The deposition of CIGS layers by co-evaporation method will be by the "three-stage process." This involves depositing the layer of three well-defined stages. It is important to control this process in order to get a quality absorber for solar cells
4
Dority, Tyler Maxwell. "The Effect of CIBS Participation and Gender on Adolescent Residential Treatment Duration." ScholarWorks, 2016. https://scholarworks.waldenu.edu/dissertations/2533.
Abstract:
Additional out-of-home placement rates for adolescents in long-term regional treatment center (LTRT) programs in the United States are between 50% and 75%. There appears to be a failure to generalize treatment to home and community in programs that do not fully integrate family involvement. The collaborative intensive bridging services (CIBS) treatment model uses intensive family therapy and brief residential treatment center (RTC) placement to reduce or eliminate use of LTRT. Using family systems theory, the purpose of this study was to determine whether participation in CIBS provided better outcomes than LTRT programs. The study used archival data collected by Family Adolescents and Children's Family Services, Inc. and children's mental health providers in a certain Minnesota county over approximately 5 years. There were 33 adolescents in the CIBS group and 33 in the LTRT group. The 3 research questions were (1) did the CIBS group have significantly fewer total out-of-home placements than the LTRT group, (2) did gender have any effect on this, and (3) were there any interaction effects on total out-of-home placement days from the combination of gender and program participation. Results of two-way ANOVA analyses showed a significant main effect for the first research question (p = .00, partial ɳ-² = .40), no significant main effect for the second (p = .46, partial ɳ-² = .01), and no significant main effect for the third (p = .15, partial ɳ-² = .03). These findings supported the position that participation in CIBS treatment resulted in statistically fewer total out-of-home placement days (TPD) than participation in LTRT. Social change implications include improved individual and family functioning for families in need as well as reduced financial expenditure for treatment.
5
Cowen, Jonathan Eric. "Liquid Phase Deposition of Copper Indium Diselenide and the Effects of Sodium." Case Western Reserve University School of Graduate Studies / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=case1373302614.
6
CIZEAU, JEANNICK. "Effet mutagene du cis-dichlorodiammineplatine(ii) chez drosophila melanogaster." Orléans, 1994. http://www.theses.fr/1994ORLE2014.
Abstract:
Le cis-dichlorodiammineplatine(ii) ou cis-ddp est une drogue antitumorale largement utilisee dans certaines therapies anticancereuses. Il reagit avec l'adn en formant des pontages intrabrins et interbrins avec les n7 des purines. Le cis-ddp a egalement une activite mutagene qui a ete determinee chez des bacteries et des cellules d'eucaryotes en culture. Le cis-ddp induit principalement des mutations ponctuelles. Nous avons etudie cet effet sur un organisme entier: drosophila melanogaster. Deux genes, white et vermilion, situes sur le chromosome x ont ete choisis comme cible de mutagenese car leur phenotype mute est facilement selectionnable. Afin d'etudier l'influence de la sequence homologue sur le spectre de mutagenese, deux experiences ont ete realisees dans deux contextes genetiques differents: male et femelle. Dans le contexte genetique male, les mutants obtenus (28 w et 4 v) correspondent a des deletions intralocus (de 4 a 109 nucleotides). Dans le contexte genetique femelle, sur 42 mutants w, 24 sont dus a des deletions intralocus (de 1 a 353 paires de bases), 18 proviennent de deletions de grande taille pouvant etre estimee a plusieurs centaines de milliers de paires de bases. Le sequencage de deux jonctions issues de large deletions montre que des sequences caracteristiques de la recombinaison illegitime sont proches des points de cassure. L'analyse de la sequence des mutations intralocus suggerent que la plupart d'entre eux resultent d'evenements de recombinaison non homologue entre deux sequences repetees situees aux bornes de la deletion, l'une etant conservee au niveau de la nouvelle jonction. De plus, la comparaison de la nature des mutations intralocus entre les deux contextes genetiques montre que la presence de la sequence homologue n'a pas d'influence sur le spectre de mutagenese du cis-ddp. Cette etude indique que le spectre de mutagenese du cis-ddp, en majorite des deletions, dans un organisme entier est tres different de celui obtenu chez des procaryotes et des cellules d'eucaryotes en culture
7
Maclear, Athlee. "Identification of cis-elements and transacting factors involved in the abiotic stress responses of plants." Thesis, Rhodes University, 2005. http://hdl.handle.net/10962/d1007236.
Abstract:
Many stress situations limit plant growth, resulting in crop production difficulties. Population growth, limited availability and over-utilization of arable land, and intolerant crop species have resulted in tremendous strain being placed on agriculturalists to produce enough to sustain the world's population. An understanding of the principles involved in plant resistance to environmental stress will enable scientists to harness these mechanisms to create stress-tolerant crop species, thus increasing crop production, and enabling the farming of previously unproductive land. This research project uses computational and bioinformatics techniques to explore the promoter regions of genes, encoding proteins that are up- or down-regulated in response to specific abiotic stresses, with the aim of identifying common patterns in the cis-elements governing the regulation of these abiotic stress responsive genes. An initial dataset of fifty known genes encoding for proteins reported to be up- or down-regulated in response to plant stresses that result in water-deficit at the cellular level viz. drought, low temperature, and salinity, were identified, and a postgreSQL database created to store relevant information pertaining to these genes and the proteins encoded by them. The genomic DNA was obtained where possible, and the promoter and intron regions identified. The Neural Network Promoter Prediction (NNPP) software package was used to predict the transcription start signal (TSS) and the promoter searching software tool, TESS (Transcription Element Search Software) used to identify known and user-defined cis-elements within the promoter regions of these genes. Currently available promoter prediction software analysis tools are reported to predict one promoter per kilobase of DNA, whilst functional promoters are thought to only occur one in 30-40 kilobases, which indicates that a large perccntage of predictions are likely to be false positives (pedersen et. al., 1999). NNPP was chosen as it was rated as the highest performing promoter prediction software tool by Fickett and Hatzigeorgiou (1997) in a thorough review of eukaryotic promoter prediction algorithms, however results were less than promising as very few predicted TSS were identified in the area 50 bps up- and downstream of the gene start site, where biologically functional TSSs are known to occur (Reese, 2000; Fickett and Hatzigeorgiou, 1997). TESS results seemed to support the hypothesis that drought, low-temperature and high salinity plant stress response proteins have similar as-elements in their promoter regions, and suggested links to various other gene regulation mechanisms viz. gibberellin-, light-, auxin- and development-regulated gene expression, highlighting the vast complexity of plant stress response processes. Although far from conclusive, results provide a valuable basis for future comparative promoter studies that will attempt to deduce possible common transcriptional initiation of abiotic stress response genes.KMBT_363
Adobe Acrobat 9.54 Paper Capture Plug-in
8
Xiao, Meisheng [Verfasser]. "Dissecting cis-regulatory effect on alternative polyadenylation using hybrid mice / Meisheng Xiao." Berlin : Freie Universität Berlin, 2016. http://d-nb.info/1117541819/34.
9
Le, Tulzo Harold. "Exploration de procédés tout-ALD via la synthèse de couches minces à base de sulfures et d’oxydes pour l’élaboration de cellules photovoltaïques de type CIGS." Electronic Thesis or Diss., Paris Sciences et Lettres (ComUE), 2018. http://www.theses.fr/2018PSLEC011.
Abstract:
Ce projet s’inscrit dans le champ thématique «Production durable et énergies renouvelables » de l’ADEME et plus particulièrement dans l’axe « Production, gestion et stockage de vecteurs énergétiques issus de sources renouvelables ». Il est proposé d’utiliser les atouts de la technique de dépôt chimique en phase vapeur par flux alternés (ALD) pour la synthèse de matériaux de haute qualité pour initier des transferts vers des procédés ALD optimisés pour l’industrialisation ainsi que permettre l’élaboration de cellules tout-ALD. Soucieux de comprendre les mécanismes de croissance impliqués, faire avancer les connaissances fondamentales liées à l’ALD et afin d’optimiser au mieux le matériau au dispositif, ce projet possède également un fort caractère exploratoire. Il s’inscrit dans les grands projets de recherches communs de l’IPVF (projet II.B en particulier), et profitera directement des ressources et compétences de l’IRDEP. L’objectif de cette thèse est d’utiliser les atouts de la technique ALD pour la synthèse de matériaux pour applications dans les futures générations de cellules solaires en couches minces CIGS. Cette technique permet le dépôt de films uniformes, couvrants et d’épaisseur contrôlée à l’échelle de la monocouche dans des conditions douces. Grâce à ses caractéristiques, elle connaît un développement spectaculaire dans le domaine industriel pour la microélectronique. Dans le domaine du photovoltaïque, le contrôle à une échelle de plus en plus précise des épaisseurs et des interfaces va également dans le sens d’une utilisation accrue de l’ALD dans les années à venir. Le cœur du projet portera sur la synthèse de matériaux et l’ingénierie fine des interfaces pour à la fois l’intégration dans des dispositifs CIGS, mais aussi l’élaboration de cellules tout-ALD. Le doctorant devra non seulement prendre en main un réacteur de dépôt ALD nouveau au laboratoire, mais surtout mettre à profit ses fonctionnalités pour la synthèse de matériaux par l’utilisation de précurseurs chimiques innovants. En parallèle, il utilisera un autre réacteur ALD équipé d’une assistance plasma qui permettra de diversifier les réactivités et le travail d’optimisation des interfaces. La compréhension des mécanismes réactionnels mises en jeu via des études in-situ (dont deux outils seront implémentés par le doctorant durant ce projet) et les caractérisations des matériaux synthétisés (DRX, MEB/EDX, transmission optique, ...) sera primordiale. En effet, cette dernière combinée à une stratégie adaptée de design des molécules permettront la synthèse de nouveaux matériaux de compositions et structures bien définies et des ingénieries d’interface à l’échelle de la monocouche atomique. Enfin, ces matériaux seront directement intégrés aux cellules CIGS, et testés pour valider les concepts et permettre le développement de dispositifs photovoltaïques plus performants et plus économes en matériau. Ils seront par ailleurs les composants fondamentaux d’une première cellule CIGS tout-ALDThe goal of this doctoral research project is to use the advantages of the ALD (Atomic Layer Deposition) technique for the synthesis of innovative materials to be used in the future generations of CIGS thin film solar cells. ALD technique allows the deposition in smooth conditions (low temperature, mbar pressure level) of conformal and uniform films, with a high control of the thickness at the atomic layer scale. Due its unique features, it is now widely applied in the field of microelectronics. In photovoltaics, the need to control at smaller scale and more accurately the thickness and the interfaces of the films implies a wide development of ALD in the next years. The main focus of this project is the synthesis of new materials with a fine interface engineering that will be integrated in CIGS devices and allows the elaboration of all-ALD solar cell. The doctoral candidate will pilot a new ALD reactor, and use its new functionalities to synthesize materials from innovative chemical precursors. In parallel, a second ALD reactor equipped with a plasma module will give access to other reactivities and allow further optimization of the interfaces. Understanding the reaction mechanisms involved via in-situ studies (for which two new analytical tools will be implemented by the student during the project) and materials characterization (XRD, SEM/EDX, optical transmission ...) will be compulsory for the success of this project. Finally, those materials will be integrated in CIGS devices, and tested to validate new concepts and allow the development of more efficient photovoltaic devices with reduced cost of atoms. In addition to this, they will be the building blocks of a first all-ALD solar cell
10
ATMANI, LOUISA. "Effet des donneurs d'electrons sur la fluorescence et l'isomerisation photochimiquetrans--cis et cis--trans des n, n'-diacylindigos." Paris 6, 1989. http://www.theses.fr/1989PA066015.
11
Eeles, Alexander. "Performance characterisation of photovoltaic devices : managing the effects of high capacitance and metastability." Thesis, Loughborough University, 2016. https://dspace.lboro.ac.uk/2134/23254.
Abstract:
It is essential to make performance measurements of photovoltaics modules in order to quantify the power they will produce under operational conditions. Performance measurements are fundamental throughout the photovoltaic industry, from product development to quality control in manufacturing and installation in the field. Rapid and economic evaluation of photovoltaic performance requires measurements using pulsed illumination solar simulators. However some devices have characteristics which can cause difficulties making these measurements. The aim of this thesis is to overcome these measurement problems focusing particularly on two of the most prevalent and pressing of these problematic characteristics: high capacitance and metastability. A new method for measuring high capacitance modules in a pulsed simulator, based on tailor made voltage ramps, was developed. The voltage ramp is tailor made such that the measurement time is minimised while maintaining high accuracy (0.5 %), allowing the measurement of high capacitance modules in a single 10ms illumination pulse. The necessary inputs for this method are the capacitance and dark current as a function of voltage for each module. In order to make these measurements, at the high forward bias voltages required, a new system was developed. The tailored voltage ramp can be created individually for each module, since the process is rapid an automatic. This makes the method applicable to a production line or to test house measurements. In addition to their use as inputs for the voltage ramp design, the capacitance and dark current also contain other valuable information, including effective minority carrier lifetime. In several thin film technologies, such as CIGS, the efficiency is not a fixed value, rather the module is metastable and the efficiency changes depending on the previous exposure /preconditioning of the device. Preconditioning is normally applied to these devices before measurement in order to put them in a specific state that is repeatable and representative of outdoor operation. Improved preconditioning practices are vital for performance measurements in CIGS modules. Therefore the preconditioning behaviour of a variety of CIGS modules from different manufacturers was investigated. The effect of preconditioning varied for different modules, commonly the fill factor improved substantially, but often changes in open circuit voltage were also seen and in some cases also substantial changes in short circuit current. The rates of preconditioning and relaxation were found to follow stretched exponential behaviour, such that the changes occur linearly on a logarithmic timescale over several orders of magnitude in time. The total time for performance stabilisation was found to vary significantly between different types of module. Because of this stretched exponential behaviour, even though the module took days to fully relax to the dark state, there was significant relaxation within the tens of minutes that it would normally take a module to cool down after light soaking before it could be measured. The major implication of observed kinetics is that in order to achieve repeatable measurement the timing in each element of a preconditioning routine should be controlled such that the fractional error in the duration of each step is small. During the investigation an unexpectedly short timescale preconditioning effect was observed, which occurs on a millisecond timescale and relaxes in seconds. It was shown that the measurement artefacts introduced using this method can be eliminated by using electrical forward bias until immediately before the measurement. Another measurement system was developed to track the dark current and C-V characteristic of the modules during electrical bias preconditioning and subsequent relaxation. These measurements demonstrate that more than one process involved during preconditioning in CIGS. Changes occur both in the doping in the bulk of the absorber and also in charge accumulation occurring near to the absorber / buffer interface. The theoretical models for preconditioning in CIGS were reviewed and compared to the experimental results. A rate model was developed based on the theory of the metastable VSe-VCu defect. This model was shown to correspond well to the rates of preconditioning and relaxation in CIGS. The non-exponential behaviour was shown to be compatible with a distribution of activation energies for the transition between different defect states. The difference in the time taken for modules to stabilise is explained by differences in doping density and the density of VSe-VCu defects. The work presented facilitates more accurate, economical performance measurements for high capacitance devices and CIGS devices, thereby contributing to the large scale implementation of photovoltaics as power source.
12
Duffett, Rodger Vincent. "The effect of cis-platinum alone or in combination with radiation on mouse lung." Master's thesis, University of Cape Town, 1999. http://hdl.handle.net/11427/26352.
Abstract:
Cis-platinum is a widely used cytotoxic agent with known radiosensitising properties. It is used in the treatment of various types of lung cancer that may include radiation to the lung as part of the treatment protocol. There is little evidence and some conflict as to whether it sensitises pulmonary tissue to the effects of radiation treatment. This project investigates the effect of cis-platinum alone or in combination with radiation on mouse lung. Four end points were used to evaluate treatments. They were: the release of pulmonary surfactant, changes in breathing rate, a histology based score of damage and changes in TGF-β - a cytokine important in the development of fibrosis. Single doses of either cis-platinum or radiation, cis-platinum given immediately before a single dose of radiation, cis-platinum given immediately before the first of two fractions of radiation and cis-platinum given at various times before and after a single dose of radiation were investigated. Cis-platinum alone was observed to cause an increase in the phospholipid content of lavaged surfactant. Cis-platinum was observed to cause an early release in surfactant and a trend existed for it to induce an early increase in breathing rates as compared to that induced by radiation alone. Cis-platinum was observed to increase radiation damage as assessed using a histology based scoring system. Higher TGF-β levels in lavaged surfactant were observed in C57 /Bl mice as compared to Balb/C. No difference in TGF-β levels was seen in homogenised lung between the strains. Cis-platinum may cause changes in TGF-β in C57/Bl mice but further work is necessary to confirm this.
13
Kulkarni, Sachin. "EFFECT OF COMPOSITION, MORPHOLOGY AND SEMICONDUCTING PROPERTIES ON THE EFFICIENCY OF CUIN1-XGAXSE2-YSY THIN-FILM SOLAR CELLS PRE." Doctoral diss., University of Central Florida, 2008. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2938.
Abstract:
A rapid thermal processing (RTP) reactor for the preparation of graded CuIn1-xGaxSe2-ySy (CIGSeS) thin-film solar cells has been designed, assembled and is being used at the Photovoltaic Materials Laboratory of the Florida Solar Energy Center. CIGSeS films having the optimum composition, morphology, and semiconducting properties were prepared using RTP. Initially films having various Cu/(In+Ga) ratios were prepared. In the next step selenium incorporation in these films was optimized, followed by sulfur incorporation in the surface to increase the bandgap at the surface. The compositional gradient of sulfur was fine-tuned so as to increase the conversion efficiency. Materials properties of these films were characterized by optical microscopy, SEM, AFM, EDS, XRD, GIXRD, AES, and EPMA. The completed cells were extensively studied by electrical characterization. Current-voltage (I-V), external and internal quantum efficiency (EQE and IQE), capacitance-voltage (C-V), and light beam induced current (LBIC) analysis were carried out. Current Density (J)-Voltage (V) curves were obtained at different temperatures. The temperature dependence of the open circuit voltage and fill factor has been estimated. The bandgap value calculated from the intercept of the linear extrapolation was ~1.1-1.2 eV. Capacitance-voltage analysis gave a carrier density of ~4.0 x 1015 cm-3. Semiconductor properties analysis of CuIn1-xGaxSe2-ySy (CIGSeS) thin-film solar cells has been carried out. The values of various PV parameters determined using this analysis were as follows: shunt resistance (Rp) of ~510 Ohms-cm2 under illumination and ~1300 Ohms-cm2 in dark, series resistance (Rs) of ~0.8 Ohms-cm2 under illumination and ~1.7 Ohms-cm2 in dark, diode quality factor (A) of 1.87, and reverse saturation current density (Jo) of 1.5 x 10-7A cm-2. The efficiency of 12.78% obtained during this research is the highest efficiency obtained by any University or National Lab for copper chalcopyrite solar cells prepared by RTP. CIGS2 cells have a better match to the solar spectrum due to their comparatively higher band-gap as compared to CIGS cells. However, they are presently limited to efficiencies below 13% which is considerably lower than that of CIGS cells of 19.9%. One of the reasons for this lower efficiency is the conduction band offset between the CIGS2 absorber layer and the CdS heterojunction partner layer. The band offset value between CIGS2 and CdS was estimated by a combination of ultraviolet photoelectron spectroscopy (UPS) and Inverse Photoemission Spectroscopy (IPES) to be -0.45 eV, i.e. a cliff is present between these two layers, enhancing the recombination at the junction, this limits the efficiency of CIGS2 wide-gap chalcopyrite solar cells.Ph.D.
Department of Mechanical, Materials and Aerospace Engineering
Engineering and Computer Science
Materials Science & Engr PhD
14
Steige, Kim A. "Cis-regulatory variation and divergence in Capsella." Doctoral thesis, Uppsala universitet, Evolutionsbiologi, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-268953.
Abstract:
Cis-regulatory changes in e.g. promoters or enhancers that affect the expression of a linked focal gene have long been thought to be important for adaptation. In this thesis, I investigate the selective importance and genomic correlates of cis-regulatory variation and divergence in the genus Capsella, using massively parallel sequencing data. This genus provides an opportunity to investigate cis-regulatory changes in response to polyploidization and mating system shifts, as it harbors three diploid species, the outcrosser Capsella grandiflora and the selfers Capsella orientalis and Capsella rubella, as well as the tetraploid Capsella bursa-pastoris. We first identify cis-regulatory changes associated with adaptive floral evolution in connection with the recent switch to self-fertilization in C. rubella and show that cis-regulatory changes between C. rubella and its outcrossing close relative C. grandiflora are associated with differences in transposable element content. Second, we show that variation in positive and purifying selection is important for the distribution of cis-regulatory variation across the genome of C. grandiflora. Interestingly, the presence of polymorphic transposable elements is strongly associated with cis-regulatory variation in C. grandiflora. Third, we show that the tetraploid C. bursa-pastoris is of hybrid origin and investigate the contribution of both parental species to gene expression. We show that gene expression in the tetraploid is partly explained by cis-regulatory divergence between the parental species. Nonetheless, within C. bursa-pastoris there is a great deal of variation in homeolog expression. In summary, this thesis explores the role of cis-regulatory changes for adaptive morphological changes in connection to a shift in mating system, the role of cis-regulatory divergence between progenitor species for an allopolyploid as well as the impact of positive and purifying selection on cis-regulatory variation within a species.
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Chandrasekaran, Vinodh. "Effect of heat treatments and reduced absorber layer thickness on cu(in,ga)se2 thin film solar cells." [Tampa, Fla.] : University of South Florida, 2005. http://purl.fcla.edu/fcla/etd/SFE0001316.
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Moua, Pachai Susan. "The effects of cis- and trans-acting mutations on recombinant protein secretion in Pichia pastoris." Scholarly Commons, 2014. https://scholarlycommons.pacific.edu/uop_etds/185.
Abstract:
Pichia pastoris is a methylotrophic yeast that has been used in both research and industrial settings for recombinant protein expression due to the ease of genetically modifying its genome, its ability to grow to large densities in inexpensive media, and its capability to perform posttranslational modifications. Multiple tools such as the cis -acting factors MATα secretion signal and MBP fusion partners, and trans-acting modifications such as the bgs mutants have increased heterologous protein secretion. Although these techniques have already been used, their effects on the protein secretory pathway have yet to be elucidated. In this study, fluorescence microscopy was used to compare the localization of proteins expressed with the mutated MATα with the deletion of amino acids 57-70 to the wild type MATα secretion signal. Additional fluorescence microscopy was completed to visualize the localization of MBP-EGFP and EGFP-MBP fusion proteins and their spatial relativity to organelle markers. EGFP-MBP was used to further distinguish the properties of multiple bgs mutants. Additionally, secreted lipase activity levels were evaluated in bgs13 strains expressing either the wild type or the mutated MAT&agr; signal peptide. The results indicated that regardless of their differences, the MATα secretion signals and bgs mutants transported their cargo proteins through similar pathways within the cells. The results of the MBP fusion proteins suggest that the arrangement of MBP significantly influences protein secretion and localization. Lastly, the bgs13 mutant with MATα secretion signals demonstrated that lipase activity increased additively when cis- and trans -acting mutations were combined. Ultimately, these results can provide better understanding of each modified factor and the protein sorting pathway, leading to potential techniques that optimize protein secretion in P. pastoris .
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Prater, Mary Renee. "Immunotoxicity of Dermal Permethrin and Cis-Urocanic Acid: Effects of Chemical Mixtures in Environmental Health." Diss., Virginia Tech, 2002. http://hdl.handle.net/10919/11047.
Abstract:
The present study examined adverse effects of sunlight exposure (mimicked by intradermal cis-urocanic acid, cUCA) on local and systemic immune responses, with or without co-exposure to the immunotoxic insecticide permethrin. A single exposure to cUCA caused diminished splenic macrophage phagocytosis that was persistent up to 30 days post-exposure. Five-day exposure to cUCA subtly increased splenocyte proliferation in response to the T cell mitogen Concanavalin A. Four-week exposure to cUCA caused increased splenic lymphocyte cellularity, thymic hypocellularity, and enhanced hydrogen peroxide production by splenic leukocytes. Single exposure to topical permethrin resulted in decreased thymic and splenic weight and cellularity, and inhibited antibody production by splenic B cells. cUCA worsened the negative effect of permethrin on both thymic weight and cellularity, and depressed splenocyte blastogenesis, hydrogen peroxide production, and antibody production. Five-day exposure to either cUCA or permethrin also caused persistent decreased contact hypersensitivity responses, an effect that became more than additive when the chemicals were administered concurrently. Defects in antigen processing and presentation by cutaneous Langerhans cells were evaluated as possible contributing mechanisms to the cutaneous immunosuppression, using mice with deleted genes. Vehicle-exposed IFNg knockout mice displayed approximately a 22.1% depression in the ear swelling response as compared to control C57BL/6N mice, suggesting that this cytokine may be required for mounting a control-level hypersensitivity response. Ear swelling in cUCA-exposed IFNg knockout mice displayed a 21.4% depressed response as compared to cUCA-exposed wild-type C57BL/6N mice, again suggesting that IFNg is an important cytokine in the contact hypersensitivity (CH) response. TNFaR knockout mice exposed to cUCA displayed 33.9% greater ear swelling than cUCA-exposed wild-type C57BL/6N mice, suggesting that increased TNFa may be involved in inhibited CH by cUCA. TNFaR knockout mice exposed to permethrin displayed 33.9% greater ear swelling than permethrin-exposed C57BL/6N mice, suggesting that increased TNFa may also be involved in inhibited CH by permethrin. C57BL/6N mice exposed to cUCA + permethrin displayed severe reduction of the CH response to 8.7% of the control level. IFNg knockout mice exposed to permethrin + cUCA showed essentially identical depression of the CH response as IFNg knockout mice exposed to either permethrin or cUCA alone. These results suggest that IFNg is required for the greater than additive immunotoxic effect that occurred when these two agents were co-administered. TNFaR knockout mice exposed to cUCA + permethrin displayed 8.7 fold greater ear swelling than similarly exposed C57BL/6N mice, again suggesting that increased TNFa is involved in inhibited CH by both cUCA and permethrin.Ph. D.
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Roger, Charles. "Developpement de cellules photovoltaïques à base de CIGS sur substrats métalliques." Phd thesis, Université de Grenoble, 2013. http://tel.archives-ouvertes.fr/tel-00965592.
Abstract:
Ces travaux de thèse ont pour but de développer des cellules photovoltaïques à base de Cu(In,Ga)Se2 (CIGS) sur des substrats métalliques. L'objectif principal consiste à résoudre les différentes problématiques liées à l'utilisation de ces substrats (Ti et acier inoxydable) en s'appuyant sur une adaptation de l'électrode arrière. L'étude est focalisée sur l'élaboration de contacts arrière en Mo par pulvérisation cathodique. Dans un premier temps, des contacts arrières en monocouches et en bicouches sont comparés, démontrant les intérêts des structures en bicouches. Ces dernières sont obtenues en utilisant successivement deux pressions différentes pendant le dépôt du contact arrière. Nous montrons que la pression utilisée pendant le dépôt de la couche inférieure influe sur la morphologie de la couche supérieure. Il en résulte des modifications de l'orientation cristalline du CIGS et des performances photovoltaïques. Dans une seconde étude, la couche inférieure est déposée à partir d'une cible de molybdène contenant du sodium (Mo:Na) afin d'apporter du Na dans le CIGS. Les différences entre le Mo et le Mo:Na sont d'abord étudiées. Nous montrons ensuite que la diffusion du sodium vers le CIGS dépend de la pression de dépôt de la couche de Mo:Na. Dans le cas de substrats en Ti, des rendements équivalents aux substrats en verre sodo-calcique sont obtenus en utilisant le molybdène dopé au sodium. Nous montrons aussi qu'en présence de sodium, l'effet de la pression de dépôt de la couche inférieure sur les performances est minimisé.
19
Gerthoffer, Arnaud. "Propriétés mécaniques des cellules photovoltaïques à base de CIGS sur substrats en verre ultra-fin." Thesis, Université Grenoble Alpes (ComUE), 2016. http://www.theses.fr/2016GREAI077/document.
Abstract:
L’objectif de ces travaux est d’étudier et de développer des cellules solaires à base de couches minces de CIGS élaborées sur un substrat innovant : le verre ultra-fin. Ce matériau possède des propriétés avantageuses, liées notamment à sa résistance aux températures élevées, à sa légèreté, à son aptitude à bloquer l’humidité, à sa transparence et à une certaine flexibilité mécanique. Nous avons ici cherché à exploiter ces propriétés pour la fabrication de cellules CIGS légères et conformables. D’abord, nous montrons la faisabilité de cellules CIGS sur des substrats en verre ultra-fin de 100 mm d’épaisseur. Nous obtenons un rendement de 12,1 % en utilisant une électrode arrière en bicouche composée d’une couche de Mo pure et d’une couche contenant du sodium, ce qui constitue le record actuel pour la technologie CIGS sur verre ultra-fin. Nous montrons ensuite que les performances des cellules peuvent se détériorer sous l’effet de flexions mécaniques répétées avec un rayon de courbure de 5 cm, en partie en raison de la formation de fissures dans les cellules. Nous présentons ensuite une étude sur les propriétés mécaniques du Mo et du CIGS, réalisée à partir d’essais de nanoindentation. La dureté et le module de Young de ces deux couches sont reportés ainsi que, pour la première fois, la ténacité et les contraintes résiduelles du CIGS. Ces résultats sont ensuite utilisés pour calculer les contraintes générées dans le CIGS lors de la flexion des cellules. Enfin, nous proposons une structure bi-verre optimisée pour limiter les contraintes dans le CIGS en flexionThe goal of this work is to study and to develop CIGS thin-film solar cells on an innovative substrate: the ultra-thin glass. This material has advantageous properties, mainly attributed to its high temperature resistance, its lightweight, its barrier property against moisture, its transparency and its mechanical flexibility. Here we tried to use these properties for the fabrication of lightweight and conformable CIGS solar cells. First, we demonstrate the feasibility of CIGS solar cells on 100 mm-thick ultra-thin glass substrates. We reached 12.1 % efficiency by using a bilayer back contact consisting of a pure Mo layer and a sodium doped Mo layer, which is up to now the record efficiency for CIGS solar cells on ultra-thin glass substrate. Then we show that solar cell performances can deteriorate under cyclic bending fatigue conditions with a radius of curvature of 5 cm. This is partially explained by the formation of cracks in the cells. Then, we report on the mechanical properties of the Mo and the CIGS layers measured by nanoindentation. The hardness and the Young’s modulus of each layer is given and, for the first time, the toughness and the residual stresses of the CIGS. These results are then used to calculate the CIGS internal stresses when the cells are bent. Finaly, we propose a glass-glass structure optimized to lower the CIGS internal stresses under bending
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Hansson, Henrik. "Understanding interfaces in thin-film solar cells using photo electron spectroscopy. : Effect of post-deposition treatment on composition of the solar cell absorber." Thesis, Uppsala universitet, Institutionen för fysik och astronomi, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-399623.
Abstract:
The increasing demand of renewable energy is the big driving force for the research and development of more efficient solar energy conversion solutions. Solar cells, which use the photovoltaic effect to convert the photon energy to electrical current, are an important solar energy conversion technique. One solar cell technology is thin-film solar cells. Thin-film solar cells use an absorption layer with a direct band gap. A direct band gap has the advantage that the photons will penetrate less deep until a photoexcitation occur compared to semiconductors with an indirect band gap (e.g. silicon). For this reason the thin-film solar cells can be made very thin.CIGS is a common thin-film solar cell absorber material containing copper (Cu), indium (In), gallium (Ga) and selenium (Se). One objective of this work has been to determine element concentrations of CIGS absorption layers from sample measurements. The GGI ratio determines the band gap, which is an important factor for optimising the efficiency of the solar cell.1 The copper vacancy is the main acceptor dopant in CIGS. The Cu concentration has shown to be important for the efficiency and for other properties of the absorber [2].The measuring technique used in this work has been photoelectron spectroscopy (PES). PES produces a spectrum showing distinct peaks corresponding to electron binding energy levels for specific element subshells. Measurements with different photon energies have been performed on samples with and without post deposition treatment (PDT). A great deal of the effort has been to calculate relative element concentrations based on the PES peak intensities. Two important parameters when performing the calculations are the photoionization cross section (including the angular dependence of the cross section) and the inelastic mean free path of the photoelectrons.The results show that the GGI and the corresponding band gap will be almost the same with and without PDT except for close to the surface where PDT lowers the GGI.The calculations showed that the copper concentration is lowest at the surface. Moreover, PDT with RbF results in lower copper concentration closer to the junction.The results show a discrepancy of the GGI and CGI ratios when using the angular dependent cross sections in [10] and [11] compared to using the cross sections in [6] and [7].Det ökande behovet av förnybar energi gör att forskning och utveckling av solenergilösningar är av största vikt. Solceller, vilka utnyttjar den fotovoltaiska effekten, är den vanligaste tekniken för omvandling av solenergi till elektricitet. Tunnfilmssolceller är en typ av solceller vars absorbent har ett direkt bandgap, till skillnad från kisel som har ett indirekt bandgap. Fördelen med ett direkt bandgap är att det ljusabsorberande materialet kan göras mycket tunt.En vanlig tunnfilmssolcell är CIGS. Det är en komposit bestående av koppar (Cu), indium (In), gallium (Ga) och selen (Se). Ett syfte med detta självständiga arbete har varit att beräkna koncentrationerna av de ingående ämnena i halvledarskiktet av CIGS. GGI-kvoten bestämmer bandgapet, vilket är en viktig faktor för solcellens verkningsgrad. Kopparvakansen är den huvudsakliga halvledaracceptorn i CIGS. Kopparkoncentrationen har visat sig vara viktig för bl.a. solcellens verkningsgrad [2].Mättekniken som används i detta arbete kallas fotoelektronspektroskopi (PES). PES-mätningar ger ett spektrum där spektrallinjerna representerar olika nivåer av elektroners bindningsenergi för olika grundämnen. Mätningar med olika fotonenergier, på prover med och utan ytbehandling (PDT), har utförts. En stor del av arbetet har varit att beräkna relativa koncentrationer av de olika grundämnena från spektrallinjerna i spektrumet. Viktiga parametrar som man behöver ta hänsyn till i uträkningarna är sannolikheten för en fotoemissionsprocess hos fotonerna, vinkelberoendet och den fria medelväglängden hos fotoelektronerna.Resultaten visar att GGI-kvot och bandgap blir nästan detsamma med eller utan PDT, förutom närmast ytan där PDT minskar GGI-kvoten.Resultaten visar också att kopparkoncentrationen är lägst på ytan och att PDT med RbF minskar kopparkoncentrationen närmast ytan.Resultaten visar att det blir skillnader mellan GGI- och CGI-kvoterna beroende på om beräkningarna baserats på vinkelberoende träffytor enligt [10] och [11] eller baserats på träffytor enligt [6] och [7].
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Lim, Herlina. "Multiple Substituent Effects on the Rate Constants for N(2)-N(3) Restricted Rotation of cis-1,3-Diphenyltriazenes." Thesis, University of Waterloo, 2006. http://hdl.handle.net/10012/2962.
Abstract:
Triazenes represent an interesting class of organic photochromic materials based on cis-trans isomerization around a nitrogen-containing double bond, and of potential use in optical memory devices. One structural property of triazenes related to cis-trans isomerization is restricted rotation around the N(2)-N(3) bond. The purpose of the study presented in this thesis is to investigate the influence of aryl substitution on the N(2)-N(3) rotational barrier of meta and/or para substituted cis-1,3-diphenyltriazenes. Rate constants for restricted rotation in cis-triazenes were measured by means of a laser-flash photolysis system, via trans-to-cis photoisomerization of corresponding trans-triazenes (which were synthesized either by classical or non-classical diazonium coupling reactions). A quantitative structure-reactivity correlation analysis of rate constants for restricted rotation of cis-triazenes was carried out in terms of an extended Hammett equation. Resulting Hammett reaction contants for restricted rotation rotation are -1. 88 ± 0. 08 and 0. 70 ± 0. 08 for N(1) and N(3), respectively, indicating that restricted rotation of cis-triazenes is more sensitive to the electronic character of the aryl group at N(1) than to than at N(3). Interestingly, the observed rate constants for restricted rotation in cyano-containing substrates are found to be pH-dependent. The latter is attributed to a change in the ionization state of the substrate, which is supported by solvent isotope effects. Furthermore, the pH dependence observed for unsymmetrical cyano-containing substrates indicates that upon deprotonation of the amino group, the negative charge concentrates either on the 4-CN substituent attached to the phenyl ring at N(3) or on the triazeno moiety. Thus, the primary cis-anionic 4-cyano-containing forms are not the same ions and do not equilibrate rapidly, since they undergo cis-to-trans isomerization. Finally, an extended Hammett equation was employed in the analysis of pKa values of trans-triazenes. The results show that there is a direct mesomeric interaction between the charge at N(3) in the triazeno moiety with 4-CN and 4-NO2 groups in the systerms studied. Consequently, the Yukawa-Tsuno modification of the Hammett equation is introduce to correlate pKa values and Hammett substituent constants
22
Metzger-Petersen, Katrin [Verfasser]. "Supplementation of a rumen-protected conjugated linoleic acid mixture (cis-9, trans-11; trans-10, cis-12) to early lactation dairy cows : effects on feed intake and performance / Katrin Metzger-Petersen." Bonn : Universitäts- und Landesbibliothek Bonn, 2013. http://d-nb.info/1043057145/34.
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Matinyenya, Patience. "South frica’s non-ratification of the United Nations convention on Contracts for the International Sale of Goods (CISG), wisdom or folly, considering the effect of the status quo on international trade." University of the Western Cape, 2011. http://hdl.handle.net/11394/2926.
Abstract:
Magister Legum - LLMThe United Nations Convention on Contracts for the International Sale of Goods 1980 (CISG) seeks to provide a standard uniform law for international sales contracts. This research paper analyses the rationale behind South Africa’s delay in deciding whether to ratify the CISG, and its possible effect on trade with other nations. The CISG drafters hoped that uniformity would remove barriers to international sales thereby facilitating international trade. Ratification of the convention is only the beginning of uniformity; uniformity must then be extended to its application and interpretation. Not all countries have ratified the Convention yet they engage in international trade in goods: this state of affairs presents challenges since traders have to choose a national law that applies to their contract where CISG does not apply. This takes traders back to the undesirable pre-CISG era. On the other hand, those States that have ratified the convention face different challenges, the biggest one being a lack of uniformity in its interpretation. The problem of differing interpretations arises because some CISG Articles are vague leading to varied interpretations by national courts. Further, the CISG is still largely misunderstood and some traders from States that have ratified CISG exclude it from application. South Africa can only ratify an international instrument such as the CISG, after it has been tabled before Parliament, and debated upon in accordance with the Constitution. CISG’s shortcomings, particularly regarding interpretation, make it far from certain that CISG would pass the rigorous legislative process. Nonetheless, the Constitution of South Africa requires the South African courts and legislature to promote principles of international law. The paper, therefore, examines, whether the Legislature has a constitutional obligation to ratify CISG. South Africa’s membership of the WTO requires that it promote international trade by removing trade barriers. It is, therefore, vital for South Africa to be seen to be actively facilitating international trade. Even though the trade benefits which flow from ratification are not always visible in States that have ratified the CISG, there is some doubt whether South Africa can sustain its trade relations without ratifying the CISG. The paper shows that the formation of contracts under the South African common law is very similar to formation as set out under Part II of the CISG and if the CISG were to be adopted in South Africa, no major changes would be needed in this regard. International commercial principles as an alternative to the CISG still require a domestic law to govern the contract and would, therefore, leave South African traders in the same position they are in currently, where their trading relations are often governed by foreign laws. Ratifying CISG would certainly simplify contract negotiations particularly with regard to governing law provisions. Overall the advantages of ratification for South Africa far outweigh the shortcomings of the CISG, and ratification will assist in ensuring that South African traders get an opportunity to enter the international trade arena on an equal platform with traders from other nations.
South Africa
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Lavoie, Monique V. "Characterisation of a conserved motif found within the Dlx cis-regulatory element URE2 and its effect on mouse URE2-lacZ activity in transgenic mice." Thesis, University of Ottawa (Canada), 2010. http://hdl.handle.net/10393/28433.
Abstract:
The Distal-less-like genes, commonly referred to as Dlx genes, encode homeodomain transcription factors essential for the establishment of GABAergic interneurons in the ventral forebrain as well as their migration to the cortex. The cis-regulatory element URE2 (enhancer) is located upstream of Dlx1 and is thought to regulate the transcription of Dlx1 and/or Dlx2. The objective of this study was to examine a short conserved sequence within the URE2 element, corresponding to nucleotides 699-719, and to evaluate its contribution to URE2 activity in transgenic mouse forebrain. My results showed that a mutant version of the URE2 element, in which nucleotides 699-719 were modified, was active in the cortex and the ventricular zone of forebrain of the transgenic mice produced with the mutant enhancer, where Dlx1/Dlx2 are not usually expressed. This indicated a loss of binding by a protein with a transcriptional repressor function. Previous analyses suggested that mURE2nt699-719 would be a good candidate for a REST repressor binding site. However, we were not able to observe any transcriptional regulation by REST in co-transfection experiments performed in cultured cells. This, as well as revised bioinformatical information, led us to identify four new candidates possibly using mURE2nt699-719 as a binding site, namely the Nuclear- Factor-1 proteins: NFIA, NFIB, NFIC and NFIX. These genes are associated with transcriptional regulation, being repressors and/or activators of gene expression in the brain. We showed that NFIC was able to utilize the mURE2nt699-719 sequence to reduce the luciferase reporter expression in neuronal cells, which would explain the loss of repression in our transgenic mice at embryonic days E11.5 and E13.5. These preliminary results also allowed us to suggest that a heterodimer between NFIC/NFIB and NFIC/NFIX binds to the mURE2699-719 sequence at embryonic day E15.5 and postnatal day 0 (P0) of the transgenic mice since the mutated enhancer's activity seems to indicate a loss of an activator at those stages. These results suggest that these factors could possibly be required for the regulation of the Dlx genes by URE2. These results will also help clarify the role of URE2 by identifying transcription factors that contribute to the genetic program involved in the cellular organization of the developing forebrain in vertebrates.
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So, Hon-hon, and 蘇漢匡. "Effects of dietary TRANS-10, CIS-12 conjugated linoleic acid on food intake and body weight regulation via central and peripheralmechanisms." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B4175816X.
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Cowie, Philip David. "Analysis of the effects of disease-associated variation within a cis-regulatory element of the CNR1 locus on CNR1 promoter dynamics." Thesis, University of Aberdeen, 2014. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=225652.
Abstract:
Genetic variation within the cannabinoid 1 receptor (CB1R) locus (CNR1) has been repeatedly associated with drug addiction pathologies. Genomic annotation of CNR1 indicates the vast majority of this genetic variation likely results in altered transcriptional regulation of the CNR1 gene as a mechanistic link to the disease phenotype. There is a lack of information describing the regulation of CNR1 transcription and the potential impact of disease-associated variation within the CNR1 locus on its transcriptional regulation. This study investigates the impact of an evolutionary conserved regulatory region of CNR1, termed ECR1, and the disease-associated variation contained within, on the transcriptional activity of the cognate CNR1 promoter region. Reporter assays conducted in primary hippocampal cells demonstrate that CNR1 promoter exhibits variable transcriptional activity during periods of CB1R signalling and cell depolarisation. Coupled to allelic variants of ECR1, the CNR1 promoter shows significant changes in transcriptional activity under resting conditions indicating that disease-associated variation within ECR1 may decrease CNR1 transcription. Further, alleles of ECR1 can drive allele-specific transcriptional responses from the CNR1 promoter during periods of CB1R stimulation and cell depolarisation. The results highlight the potential for disease-associated regulatory variation of the CNR1 locus to create stratified transcriptional responses to specific cell signalling scenarios and putatively to clinical strategies employing pharmacological agents. Furthermore, investigation of DNA-protein interactions at the allelic ECR1 region demonstrate that disease-associated variation within ECR1 alters DNA-protein interactions within the nucleus consistent with a decrease in transcriptional activity in the disease-associated allele variant. Collectively the current work supports the hypothesis that disease-associated variation within the ECR1 regulatory region of the CNR1 locus has the capacity to significantly impact on CNR1 promoter transcriptional activity. It is posited that allele-specific transcriptional effects may have a major impact on the susceptibility of individuals to drug addiction or on responses to clinical pharmacological treatments.
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Honorato, Sara Braga. "Antioxidant effect of components of the latex from seringueira (Hevea brasiliensis)and mangabeira(Hancoria speciosa)on thermo-oxidative degradatiion of synthesic Poly (1,4-cis-isoprene." Universidade Federal do CearÃ, 2005. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=1429.
Abstract:
FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgicoFundaÃÃo de Amparo à Pesquisa do Estado do CearÃ
Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico
This work is divided into two parts: The first is associated with the isolation of non-isoprenic components from the natural rubber (NR) latex from seringueira (Hevea brasiliensis) and mangabeira (Hancornia speciosa) by centrifugation. In the first centrifugation the phase serum was isolated (MAT 1). The rubber phase was treated with the surfactant sodium dodecyl sulphate (SDS) and isolated after the third centrifugation (MAT 2). The other materials tested in the synthetic rubber (PIS) were CENT 1, CENT 2 and the NR extract. These were kindly provided by Prof Jean Marinho from UNESP. The second part is associated with the possible antioxidant effect of the isolated latex components on the thermo-oxidative degradation of synthetic poly(1,4-cis-isoprene) carried out via infrared (FT-IR), thermogravimetric analysis (TG) and Nuclear Magnetic Resonance (RMN). It was observed that, from the substances obtained from the purification of the latex and tested on synthetic PIS, both MAT 1 and CENT 1 have pro-oxidant effects. The remain can be ordered in the following sequence in regards to their antioxidant capabilities: PIS + MAT 2 > PIS + NR EXTRACT > PIS + CENT 2 The calculation of the activation energy of the thermal degradation of PIS in synthetic air containing 2.0% of MAT 2 confirms that the stabilizer effect of PIS increases with the increase of this material, as all Ea of pure polymer are inferior to that of the doped sample. The NMR spectra for MAT 2 showed, in addition to the characteristic bands of cis-1,4-polyisoprene, also bands associated with fatty acids and/or SDS. The spectra of NR extract showed bands that are characteristic of oligosaccharides and minoritary cis-1,4-polyisoprene.
O presente trabalho à dividido em duas partes: A primeira està relacionada com o isolamento dos componentes nÃo-isoprÃnicos do lÃtex da borracha natural (BN) da seringueira (Hevea brasiliensis) e mangabeira (Hancornia speciosa) por centrifugaÃÃo. Na primeira centrifugaÃÃo foi isolada a fase serum (MAT 1). A fase borracha foi tratada com o surfactante dodecil sulfato de sÃdio (SDS) e isolada apÃs a terceira centrifugaÃÃo, (MAT 2). Os outros materiais testados à borracha sintÃtica (PIS) foram o CENT 1, CENT 2 e o extrato de BN, os quais foram gentilmente cedidos pelo Prof. Jean Marinho da UNESP. A segunda parte refere-se ao possÃvel efeito antioxidante dos componentes do lÃtex isolados sobre a degradaÃÃo termo-oxidativa do poli (1,4-cis-isopreno) sintÃtico realizada atravÃs das tÃcnicas de Infravermelho (FT-IR), AnÃlise TermogravimÃtrica (TG) e RessonÃncia MagnÃtica Nuclear (RMN). Foi observado que, das substÃncias obtidas da purificaÃÃo do lÃtex e testadas no PIS sintÃtico, tanto o MAT 1 quanto o CENT 1 tÃm efeitos prÃ-oxidantes. Os demais podem ser ordenados na seguinte seqÃÃncia quanto ao poder antioxidante: PIS + MAT 2 > PIS + EXTRATO DE BN > PIS + CENT 2 O cÃlculo da energia de ativaÃÃo (Ea) da degradaÃÃo tÃrmica do PIS em ar sintÃtico contendo 2,0% do MAT 2 confirma que o acrÃscimo desse material exerce um efeito estabilizante ao PIS, pois todas as Ea do polÃmero puro sÃo inferiores à da amostra dopada. Os espectros de RessonÃncia MagnÃtica Nuclear para o MAT 2 exibiram, alÃm de sinais caracterÃsticos do cis-1,4-poliisopreno, sinais relativos a Ãcidos graxos e/ou SDS, enquanto que os espectros do Extrato de BN exibiram sinais caracterÃsticos de oligossacarÃdeos e poli (1,4-cis-isopreno) como componentes minoritÃrios.
28
Bretherton, Nicola. "The effect of cis-5,8,11,14,17-eicosapentaenoic acid upon the contractile mechanisms linked to calcium influx and the mobilisation of intracellular calcium in aortic smooth muscle." Thesis, Aston University, 1998. http://publications.aston.ac.uk/10988/.
Abstract:
Epidemiological studies previously identified cis-5,8,11,14,17-eicosapentaenoic acid (EPA) as the biologically active component of fish oil of benefit to the cardiovascular system. Although clinical investigations demonstrated its usefulness in surgical procedures, its mechanism of action still remained unclear. It was shown in this thesis, that EPA partially blocked the contraction of aortic smooth muscle cells to the vasoactive agents KCl and noradrenaline. The latter effect was likely caused by reducing calcium influx through receptor-operated channels, supporting a recent suggestion by Asano et al (1997). Consistently, EPA decreased noradrenaline-induced contractures in aortic tissue, in support of previous reports (Engler, 1992b). The observed effect of EPA on cell contractions to KCl was not simple due to blocking calcium influx through L-type channels, consistent with a previous suggestion by Hallaq et al (1992). Moreover, EPA caused a transient increase in [Ca2+]i in the absence of extracellular calcium. To resolve this it was shown that EPA increased inositol phosphate formation which, it is suggested, caused the release of calcium from an inositol phosphate-dependent internal binding site, possibly that of an intracellular membrane or superficial sarcoplasmic reticulum, producing the transient increase in [Ca2+]i. As it was shown that the cellular contractile filaments were not desensitised to calcium by EPA, it is suggested that the transient increase in [Ca2+]i subsequently blocks further cell contraction to KCl by activating membrane-associated potassium channels. Activation of potassium channels induces the cellular efflux of potassium ions, thereby hyperpolarising the plasma membrane and moving the membrane potential farther from the activation range for calcium channels. This would prevent calcium influx in the longer term and could explain the initial observed effect of EPA to block cell contraction to KCl.
29
So, Hon-hon. "Effects of dietary TRANS-10, CIS-12 conjugated linoleic acid on food intake and body weight regulation via central and peripheral mechanisms." Click to view the E-thesis via HKUTO, 2009. http://sunzi.lib.hku.hk/hkuto/record/B4175816X.
30
Petit, Jean-Marie. "Effet hypnogène de l'acide 13-cis-rétinoïque chez le rat : arguments en faveur de l'implication du VIP : approches polygraphique, immunohistochimique et biochimique." Lyon 1, 1995. http://www.theses.fr/1995LYO1T207.
31
Mata, Xavier. "Analyse structurale et fonctionnelle de gènes voisins du "locus" de l'α-lactalbumine caprine : application à la recherche d'éléments "cis"-régulateurs à effet dominant." Limoges, 2003. http://www.theses.fr/2003LIMO0033.
Abstract:
L'utilisation récente de grands fragments d'ADN (BACs et YACs) a permis de s'affranchir de " l' effet de position "en transgénèse. Cela a été le cas pour un BAC caprin de 160 kb contenant le gène de l'a-lactalbumine (BAC 41), suggérant la présence d'éléments cis-régulateurs dominants. Mon sujet de thèse visait à analyser plus finement cet insert. Des expériences de transgénèse utilisant un BAC raccourci dérivé (BAC 6) nous a permis d'effectuer une primo-localisation de ces éléments. Dans cette région deux loci ont été identifiés : celui de la cycline T1 et FLJ20436. Leur caractérisation fonctionnelle a permis de montrer qu'ils sont actifs au sein du BAC et à expression ubiquiste. De façon inattendue, l'utilisation du promoteur de la cycline T1 en transgénèse a conduit à unessur-expression dans la lignée germinale mâle. Le gène FLJ20436 présente un épissage complexe. Ces études nous ont amenés à suspecter la présence de deux domaines chromatiniens putatifs séparant ces gènes à expression ubiquiste de celui de l'a-lactalbumine. L'analyse structurale de ces loci a permis de dresser une carte précise du BAC 41 et de délimiter une région frontière séparant les deux domaines chromatiniens putatifs. Une recherche en son sein d'éléments cis-régulateurs dominants a été initiée. L'identification et l'association de tels éléments au promoteur du gène de l'a-lactalbumine devraient contribuer à la mise au point de vecteurs d'expression efficients pour la transgénèse mammaireThe recent use of large genomic fragment (BACs or YACs) has allowed to avoid this "position effect". This has been observed with a vector that was developed in our laboratory that consists of a 160 kb goat BAC insert (BAC 41) encompassing the a-lactalbumin gene, suggesting the occurrence of dominant cis-regulatory elements. The aim of this thesis was to further analyse this insert. Transgenic experiments using a derived shorter BAC of 60 kb allowed us to localise these regulatory elements in a 5' distal region of the a-lactalbumin locus. In this region two loci were identified: the cyclin T1 and FLJ20436. Characterisation of these genes revealed that they were functional within the BAC 41 and ubiquitously expressed. Surprisingly, the use of the cyclin T1 promoter in transgenics resulted in an ubiquitous expression unexpectedly high only in male germ cells. FLJ20436 pre-mRNA has a very complex splicing pattern that is conserved during evolution. These observations led us to suspect the occurrence of two chromatin domains separating these ubiquitously expressed genes from the a-lactalbumin one. Structural analysis of these genes has allowed to define a precise restriction map of the BAC 41 and to precise the location of the potential border region within the two chromatin domains. Search for cis-regulatory elements within this region was initiated. There identification and association with the a-lactalbumin promoter should contribute to the creation of efficient mammary specific expression vectors
32
Lapeyre, Pascale. "Nouveaux aspects anatomo-fonctionnels des cellules ciliées vestibulaires de type 1 : morphologie des touffes ciliaires, motilité cellulaire réversible et modulation GABAergique de l'excitabilité des cellules de type 1 du cobaye." Bordeaux 2, 1992. http://www.theses.fr/1992BOR28206.
33
House, Ralph Lee. "Functional Genomic Characterization of the Anti-Adipogenic Effects of trans 10, cis 12-Conjugated Linoleic Acid (t10c12-CLA) in a Polygenic Obese Line of Mice." NCSU, 2004. http://www.lib.ncsu.edu/theses/available/etd-07292004-115209/.
Abstract:
We analyzed gene expression during t10c12-CLA-induced body fat reduction in a polygenic obese line of mice. Adult mice (N=185) were allotted to a 2x2 factorial experiment consisting of a non-obese (ICR-control) and an obese (M16-selected) line of mice fed a 7% fat, purified diet containing either 1% linoleic acid (LA) or 1% t10c12-CLA. Body weight (BW) gain by day 14 was 12% lower in CLA compared to LA fed mice (P<0.0001). By day 14, t10c12-CLA reduced weights of epididymal, mesenteric and brown adipose tissues as a percentage of BW in both lines by 30, 27 and 58%, respectively, and increased liver weight/BW by 34% (P<0.0001). Total RNA was isolated and pooled (4-5 mice per composite) from epididymal adipose (day 5 & 14) and liver (day 14) of the obese mice to analyze gene expression profiles using Agilent mouse oligo microarray slides (4 per tissue?day) representing >20,000 genes. Numbers of genes differentially expressed by ≥ two fold in epididymal adipose (day 5 & 14) and liver (day 14) were 29, 125, and 80, respectively. Of particular interest in adipose, CLA putatively increased expression of the uncoupling proteins (1 and 2), carnitine palmitoyltransferase (L and M), and carnitine translocase, but decreased expression of PPAR-gamma, GLUT-4, perilipin, caveolin-1, adiponectin and resistin (P<0.01). In conclusion, this experiment has revealed candidate genes that will be useful in elucidating mechanisms underlying the potent anti-adipogenic effects of t10c12-CLA.
34
Betz, Helene [Verfasser], and Sebastian [Akademischer Betreuer] Sauerbier. "Effekt von Trans-8-tert-butyl-GABA-Pentin-Lactam und Cis-8-tert-butyl-GABA-Pentin-Lactam auf das Proliferations-und Differenzierungsverhalten von humanen mesenchymalen Stammzellen." Freiburg : Universität, 2013. http://d-nb.info/1123475741/34.
35
Donaldson, Kathryn Marie. "Relationships between chromosome structure and long distance regulation of gene expression : a study of cis and trans modifiers of terminal deficiency-associated position effect variegation in a Drosophila melanogastor minichromosome /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2000. http://wwwlib.umi.com/cr/ucsd/fullcit?p9987530.
36
Pereira, André Luiz Araújo 1981. "Identificação de genes de Citrus sinensis com expressão dependente da proteína PthA de Xanthomonas citri e isolamento de elementos cis regulatórios ligantes de PthA." [s.n.], 2011. http://repositorio.unicamp.br/jspui/handle/REPOSIP/314050.
Abstract:
Orientador: Celso Eduardo BenedettiTese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia
Made available in DSpace on 2018-08-19T05:56:46Z (GMT). No. of bitstreams: 1 Pereira_AndreLuizAraujo_D.pdf: 43759919 bytes, checksum: 379266575f1db46c7d620232efb9ba13 (MD5) Previous issue date: 2011
Resumo: O cancro cítrico resulta da interação compatível entre a bactéria Xanthomonas axonopodis pv. citri e Citrus spp. A doença não tem cura, é de fácil disseminação e difícil controle. O cenário é preocupante, pois a doença diminui drasticamente o rendimento e a qualidade dos frutos de plantas infectadas, ocasionando um forte impacto econômico na citricultura mundial. Os principais sintomas do cancro cítrico, resultantes dos processos de hipertrofia (aumento do volume celular) e hiperplasia (aumento da divisão celular), são dependentes da proteína efetora PthA de X. citri. PthA integra a família de fatores de transcrição conhecida como efetores ativadores de transcrição (transcription activator-like ou TAL). O principal homólogo de PthA é o efetor AvrBs3 de X. campestris pv. vesicatoria que atua regulando a transcrição de genes do hospedeiro em benefício do patógeno. A similaridade entre estas proteínas gira em torno de 97%, sugerindo, portanto, função semelhante para PthA. Através de uma série de microarranjos, investigou-se o perfil de expressão gênica de laranja doce (Citrus sinensis) dependente de PthA (X. citri) e de PthCs de X. aurantifolii, uma bactéria que causa cancro cítrico apenas no limão galego e que, em laranja doce, induz uma reação de hipersensibilidade. Desta forma, verificou-se a regulação positiva ou negativa de uma série de genes. Os PthCs regularam negativamente genes associados à sinalização por auxina e induziram a expressão de genes de defesa e silenciamento gênico. Em contrapartida, PthAs induziram uma série de genes intimamente relacionados aos sintomas de cancrose, incluindo: genes associados aos processos de aumento e divisão celular, síntese e remodelamento de parede celular, bem como genes envolvidos na sinalização por auxina e giberelina. Neste sentido, efetuou-se o isolamento de regiões promotoras de cinco genes, os quais são potencialmente regulados por PthA. A análise destas regiões revelou a presença de um possível TATA-box notavelmente semelhante àquele encontrado no gene upa20, denominado UPA-box (up-regulated por AvrBs3), sugerindo que estes genes poderiam ser transativados por PthA em citros. De fato, ensaios de retardamento de mobilidade eletroforética (electrophoretic mobility shift assay ou EMSA), demonstraram a ligação específica de PthA2 e 4 ao TATA-box encontrado na região promotora do gene que codifica uma proteínas relacionada à patogênese (pathogenesis-related proteins ou PR). Este resultado corrobora com a hipótese de que os efetores TAL atuam como proteínas ligadoras de elementos TATA. Finalmente, experimentos de co-imunoprecipitação de cromatina (ChIP) e cotransformação demonstraram, ainda que em resultados preliminares, que particularmente PthA4 é capaz de transativar pr5 in planta. Embora o cancro cítrico ainda não seja completamente entendido a nível molecular, os dados aqui apresentados sugerem fortemente a ação de PthAs como fatores de transcrição, bem como aponta candidatos à regulação positiva intimamente associados aos processos de hipertrofia e hiperplasia. Além disso, as regiões promotoras aqui isoladas podem ajudar no desenvolvimento de novas estratégias para a geração de plantas resistentes à cancrose
Abstract: Citrus canker is a result of a compatible interaction between Xanthomonas axonopodis pv. citri and Citrus spp. There is no cure for citrus canker, and the disease is easily spread and difficult to be managed. The scenario is threatening since the disease dramatically diminishes the quality of fruits in infected plants leading to great economic losses for the world citrus producers. The main citrus canker symptoms known as hypertrophy (cell enlargement) and hyperplasia (cell division) are PthA-dependent. PthA is an effector protein from X. citri which belongs to the TAL effectors (transcription activatorlike) family. The closest homologue of PthA is AvrBs3 from Xanthomonas campestris pv. vesicatoria, a TAL effector that acts as a transcriptional factor to modulate host transcription to the pathogen's benefit. Similarity shared by these two proteins is around 97%, suggesting that PthA plays a similar role in the citrus host. Through a number of microarray experiments, we investigate the gene transcription in sweet orange (Citrus sinensis) in response to the transient expression of PthA from X. citri or PthC from X. aurantifolii, pathotype C, a bacteria that causes citrus canker in Mexican lime but in orange trigger a hypersensitive response in sweet orange. We observed that PthCs down-regulated various auxin signaling genes and induced the expression of genes involved in defense and gene silencing. On the other hand, PthAs induces several genes implicated in canker development such as cell division and elongation, cell-wall synthesis and remodeling, synthesis, mobilization and signaling of auxin and gibberellin. Promoter regions of PthA-induced genes were isolated and shown to have predicted PthA and PthC binding sites at or near their putative TATA boxes. Moreover, competition gel shift assays confirmed that PthA4 shows preferential binding to the TATA box of the pathogenesis-related (pr5) gene promoter, supporting the idea that TAL effectors may act as general TATA-binding proteins. Finally, both chromatin immunoprecipitation (ChIP) and co-transformation assays demonstrated however as preliminary results, that PthA4 is able to transactivate pr5 in planta. Albeit the molecular mechanism by which citrus canker develop remains elusive at the molecular level, we provided data supporting the notion that PthA acts as a transcriptional factor, as well as identified PthA-induced genes associated with hypertrophy and hyperplasia. Furthermore, the promoter regions isolated here might be useful to obtain citrus plants resistant to the canker bacteria
Doutorado
Bioquimica
Doutor em Biologia Funcional e Molecular
37
Lee, Heekyoung Verfasser], Johann Josef [Akademischer Betreuer] [Gutachter] Hauner, and de Angelis Martin [Gutachter] [Hrabé. "Understanding the molecular mechanism underlying the effect of cis-regulatory variants on gene expression at T2D associated loci / Heekyoung Lee ; Gutachter: Martin Hrabé de Angelis, Johann Josef Hauner ; Betreuer: Johann Josef Hauner." München : Universitätsbibliothek der TU München, 2016. http://d-nb.info/1135724830/34.
38
Ceddia, Ryan Patrick. "Genomic Characterization of Two Models of Obesity in Mice: Divergent Selection for Epididymal Fat and the Effects of trans-10, cis-12-Conjugated Linoleic Acid." NCSU, 2007. http://www.lib.ncsu.edu/theses/available/etd-08072007-120016/unrestricted/etd.pdf.
39
Muller, Fabrice. "Mémoire présenté en vue de l'obtention de L'Habilitation à Diriger des Recherches." Habilitation à diriger des recherches, Université d'Orléans, 2004. http://tel.archives-ouvertes.fr/tel-00067858.
Abstract:
L'étude des propriétés des minéraux argileux et en particulier des phyllosilicates 2:1 dioctaédriques nécessite une analyse à différentes échelles de leurs caractéristiques. Les résultats exposés concernent l'échelle locale (organisation structurale interne du feuillet, interaction cation - feuillet) et semi-locale (nature des empilements). Dans un premier temps sont présentés des travaux centrés sur les relations d'ordre-désordre dans l'organisation des cations octaédriques majeurs (Al, Fe, Mg). La distribution des cations n'est pas aléatoire mais structurée en domaines qui peuvent être monocationiques (Fe ou Al) ou de composition cationique mixte. Dans ce dernier cas, la tendance est à l'homogénéisation des déficits de charges. Dans un second temps sont étudiées des transformations structurales induites par des traitements thermiques (déshydroxylation) et hydrothermaux (réhydroxylation). Des modèles de migration cationique à l'intérieur des couches octaédriques sont proposés pour expliquer les évolutions de structure. La composition et la distribution cationique des couches octaédriques jouent un rôle primordial dans les processus. Les traitements sont responsables, dans le cas des smectites, d'une augmentation du désordre dans la distribution des feuillets à différentes couches d'eau et d'une diminution des propriétés d'hydratation pour certains feuillets.
Les projets en cours, sur les interactions molécules organiques - argiles, sont présentés dans une dernière partie. Les aspects structuraux sont principalement développés (organisation de l'espace interfoliaire, rôle sur l'organisation micro-texturale de la phase argileuse).
40
Blanchet, Christophe. "Caractérisation de la réponse cholinergique des cellules ciliées externes cochléaires." Bordeaux 2, 1997. http://www.theses.fr/1997BOR28490.
41
Zervos, Michel. "Réactivité des aminonitriles vis à vis des cyclénones et comparaison avec celle des éthers de cyanhydrines : stéréochimie et conformation des cyclanones 2,3 disubstituées." Paris 11, 1986. http://www.theses.fr/1986PA112007.
Abstract:
Cette thèse décrit l'addition conjuguée des dérivés lithiés équivalents d'acyle tels que les éthers de cyanhydrines et les aminonitriles aux α-cyclénones diversement substituées suivie de la protonation des énolates formés. L'action des équivalents de benzoyle sur les α-cyclénones α-substituées conduit aux adduits 1,4 de stéréochimie cis. D'autre part, contrairement aux éthers de cyanhydrines, les aminonitriles ne réagissent pas avec des α-cyclénones β-substituées. Par contre, en présence d'acides de Lewis leur réactivité vis à vis d'αénones encombrées est largement augmentée. Le piégeage des énolates formés par différents électrophiles a été aussi examiné. Dans le cas des éthers de cyanhydrines l'alkylation par l'iodure de méthyle conduit aux adduits trans quelle que soit la taille du cycle. Par contre, avec les aminonitriles cette réaction est limitée à la série cyclopentanique. Néanmoins avec un électrophile très réactif tel que le bromacétate d'éthyle on obtient des cyclohexanones 2,3 disubstituées trans. Contrairement aux aminonitriles équivalents de formyle ceux d'acétyle réagissent vis à vis des α-cyclénones α-substituées d'une manière comparable à celle des équivalents de benzoyle. Dans tous les cas les acyl-3 cyclanones substituées en position 2 ont été obtenues avec conservation de la stéréochimie cis ou trans des adduits de départ sauf en série cyclopentanique. L'étude conformationnelle par H RMN 2D des sélénophényl-2 cyclo hexanones 3-substituées a révélé une préférence du groupe PhSe pour la position axiale. Une stabilisation résultant d'un recouvrement des orbitales σ* de la liaison C-SePh et des orbitales π du carbonyle a été proposéeThe present work describes the conjugate addition of latent acyl anion equivalents such as protected cyanohydrines and N-dialkyl aminonitriles to cyclic α,β unsaturated enones diversely substituted followed by protonation of the intermediate formed enolates. The reaction of benzoyl equivalents on α-substituted α-cyclénones leads to 1,4 adducts possessing a cis stereochemistry. The aminonitriles don't react with the β,β-disubstituted α-enones and these results are in contradiction with the literature data concerning similar reactions with the corresponding cyanohydrin ethers. Nevertheless, their reactivity towards sterically hindered α-enones is largely increased in the presence of Lewis acids. The trapping of the intermediate enolates with various electrophiles is also examined. In the case of protected cyanohydrines the alkylation with methyl iodide leads to the trans adducts whatever the ring size may be. On the contrary, when using an aminonitrile this reaction is limited to the five membered ring series. However, with a more reactive electrophile such as the ethyl bromoacetate we obtain the 2,3-disubstituted trans cyclohexanones. The reaction of aminonitriles acetyl equivalents on a-substituted a-cyclenones gives results comparable with those of the benzoyl equivalents while masked formyl anions lead to cis-trans mixtures. From all 1,4 adducts the corresponding 2-substituted 3-acyl cyclanones were prepared preserving their cis or trans stereochemistry except for the cyclopentanone series. The 1H NMR 2D configurational and conformational study of the 3-substituted 2-phenylseleno cyclohexanones showed a preference of the SePh group for the axial position. To explain these results we propose a stabilization resulting from an overlap of the σ* orbitals of the C-SePh bond with the π orbitals of the neighboring carbonyl
42
Perny, Sébastien. "Alignement de cristaux liquides par irradiation en lumière linéairement polarisée de film minces de polymères photoréticulables." Cachan, Ecole normale supérieure, 1998. http://www.theses.fr/1998DENS0042.
Abstract:
L'objectif de ce travail de thèse a été en premier lieu de concevoir et de synthétiser quatre polymères photosensibles utilisables industriellement comme films d'alignement des cristaux liquides. Dans un deuxième temps, des études par spectroscopie UV et IR ont permis de caractériser l'anisotropie et l'évolution de la composition de ces matériaux en cours d'irradiation en lumière linéairement polarisée. Dans le cas général, il a ainsi été possible de mettre en évidence la compétition de deux photo réactions : la cycloaddition 2+2 et l'isomérisation trans/cis. Ainsi, trois espèces cohabitent au sein du film de polymère irradié : les dimères, produits de la cycloaddition de chromophores agrégés ; les isomères cis, issus de l'isomérisation des chromophores isoles ; les chromophores initiaux qui n'ont pas réagi. De plus, nous avons pu constater que l'orientation préférentielle des chromophores inchangés était perpendiculaire a l'axe de polarisation et que, dans certains cas, les dimères étaient préférentiellement formes parallèlement a l'axe de polarisation. Enfin les propriétés d'alignement de ces matériaux ont été étudiés en confinant des cristaux liquides entre deux films de photopolymères irradies. Leur comportement a ensuite été compare a ceux du pvci et du poly(7-methacryloyloxycoumarine) afin de clarifier le mécanisme de photo alignement. Deux mécanismes ont du être envisages. Dans un cas, la sélectivité axiale des réactions photochimiques en lumière polarisée consomme les chromophores préférentiellement orientes le long de l'axe de polarisation. L'anisotropie du film est donc uniquement due à la présence de chromophores inchangés, initialement perpendiculaires à l'axe de polarisation, et le film induit un alignement homogène planaire suivant cet axe. Dans le deuxième cas, l'anisotropie du film est essentiellement due à la formation de dimères le long de l'axe de polarisation, et le film induit un alignement homogène planaire suivant l'axe de polarisation.
43
Lin, Jhih-Yu, and 林芷羽. "Effect of Precursors on the formation of crystalline phase of CIS and CIGS powders." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/60966841405130469960.
Abstract:
碩士中原大學
化學研究所
97
Solar cells with chalocopyrite structure have two major types: copper indium selenium series, CuInSe2[CIS], and copper indium gallium selenium series, Cu(In1-xGax)(Se1-ySy)[CIGS]. Due to the advantages of high photoelectric efficiency and low materials cost, it is worth to keep studying these two material systems. In this experiment, three kinds of different precursors were used to synthesize CIS and CIGS powder. XRD, SEM, EDS, and TEM were then used to analyze crystallization, composition, particle size, and morphology of powder products. The composition of the product can be adjusted when salts of CuCl2, InCl3, and SeCl4 were used to synthesize the CIS powder. The product can be single phase if precursors of [Cu4{Se2P(O’Pr) 2}4] and [In{Se2P(O’Pr) 2}3] were used. It is hard to synthesize CIGS powder by using Cu, In, Ga, and Se powder directly, because all these powder can not be completely dissolved into the solvent used in this experiment. The composition of the product can be adjusted when salts of CuCl2, InCl3, GaCl3 and SeCl4 were used to synthesize the CIGS powder. The product can be almost single phase if precursors of [Cu4{Se2P(O’Pr) 2}4], [In{Se2P(O’Pr) 2}3], and GaCl3 were used.
44
Zhu, Xiaobo, and 朱曉波. "CIGS TFT and inhomogeneity effects on CIGS solar cells." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/13757512392852824787.
Abstract:
博士國立臺灣大學
電子工程學研究所
104
Cu(Ga, In)Se2 (CIGS) thin film transistors and the inhomogeneity effects on CIGS solar modules are investigated. CIGS is one of the best candidate materials for thin film solar cell due to its strong light absorption as well as its relatively high mobility. It also has the advantage to reduce production cost for photovoltaics devices, and nowadays, the fabrication of CIGS solar cell is mature and commercial. But some problems like uniformity, morphology, and yield still affect the quality of CIGS solar cell and reduce its market in the competition with other kinds of solar cell like Si based solar cell, CdTe solar cell and CZTS solar cell. Besides the application in thin film solar cell, CIGS also has the potential to have a role in other fields, like light sensor, telecommunication, and thin film transistor (TFT). By solving the problems occurred in the fabrication of CIGS solar cell and achieving its application in other fields will promote the value of CIGS. In the first part of this dissertation, CIGS TFT is investigated. The fabricated CIGS TFT achieves a saturation mobility of ~1.8 cm2/V-s, and the on-off ratio over 3 orders of magnitude for the first time. We use a special ring pattern to simplify the fabrication process and avoided the problems occurred in the traditional TFTs. In the structure of CIGS TFT, Al2O3 is deposited by atomic layer deposition (ALD) on CIGS film as the dielectric layer. With the help of Al2O3 layer, the on current is high due to its high dielectric constant, and moreover, the channel can be passivated by Al2O3 layer, so that defects on the interface of CIGS/Al2O3 decrease, and eventually increase the saturation mobility. We also have applied thin-down process on the CIGS thin film, which was prepared for solar cell fabrication, to meet the required conditions for CIGS TFT. The characteristics of CIGS TFT are investigated consequently, and the improvement of saturation mobility after thin down process is found. This might be due to the different qualities of different layers in CIGS thin film, and is justified by the measurements of photoluminescence (PL) and X-ray diffraction (XRD). Moreover, the performances of CIGS TFTs with different content in CIGS films are investigated. TFT with high Cu/(Ga+In) ratio tends to have both high carrier concentration and saturation mobility. Sodium atoms might play important roles in these properties. In the second part of this dissertation, the inhomogeneity effects on CIGS solar modules are investigated. We firstly demonstrate the impact of residual strain on the CIGS solar module with Ga content fluctuation using first principle calculations. The simulation results show that the inhomogeneity effect is magnified by residual strain due to the enhanced band gap fluctuations. Then the 3D simulation results of CIGS solar cells are obtained with the residual strain effect incorporated. The parameters used in the model for the simulation are the same to those used in the commercial CIGS solar cell. A module consists of 3 cells in series, while each cell is divided into 3 sections. Intracell inhomo, intercell inhomo, and combined intracell+intercell inhomo are considered within a module, and the effects of both Ga content and thickness fluctuation are investigated. Among these three distributions, intracell+intercell inhomo is closest to the real distribution of inhomogeneity in the fabrication of CIGS solar module. In reality, Ga content fluctuation is serious and thickness fluctuation can be well controlled. The simulation results show that in terms of Ga content fluctuation, Intracell fluctuation causes VOC degradation, and intercell fluctuation causes JSC and fill factor degradations, and in terms of thickness fluctuation, VOC remains the same due to the constant Ga content, JSC is degraded due to the increase of excess carrier recombination, and the tendency of fill factor degradation is similar to Ga content fluctuation.
45
Fu, Jinlong. "Thermal cis-to-trans isomerization mechanism of N-(phenylazo)-substituted nitrogen heterocycles." Thesis, 2008. http://hdl.handle.net/10012/4134.
Abstract:
Triazenes, compounds containing a diazoamino moiety (–N(1)=N(2)–N(3)<), are known for their reversible cis-trans isomerization character and hence, have the potential to be used in photoswitchable devices and photostorage media. However, little is known about their cis-trans isomerization mechanism. In this thesis, kinetic studies on the thermal cis-to-trans isomerization of N-(phenylazo)-substituted nitrogen heterocycles are presented. It is shown that the isomerization rate constant increases as the size and electron-donating character of the cyclic amine increases, as the electron-withdrawing character of the para substituent group on the phenyl ring increases, and as the polarity of the solvent increases. All these trends are interpreted in terms of a rotational isomerization mechanism involving a dipolar transition state. In addition, photolytic cleavage of the N(2)–N(3) bond of target substrates is shown to be affected as well by the size and electronic character of the cyclic amine, the electronic character of the phenyl ring substituent, and the polarity of the solvent, with the result that the photolysis yield increases as the isomerization rate decreases.
Theoretical calculations on target substrates both in the gas phase and various solvents were also performed based on DFT-B3LYP/6-31+G* method. Overall, the cis-to-trans isomerization is predicted to take place through rotation around the N(1)=N(2) bond. Furthermore, the calculated energy barriers are found to be influenced by the size and electronic character of the cyclic amine, the electronic character of the phenyl ring substituent, and the polarity of the solvent, consistent with the effects obtained experimentally from the kinetic studies.
46
Chen, Jun Yu, and 陳俊宇. "Defect Related Effects of CIGS and." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/90619720768354920320.
Abstract:
碩士國立臺灣大學
電機工程學研究所
99
In this thesis, the photoluminescence, external quantum efficiency and J-V curve measurement are used to characterize defect information for Cu(In,Ga)Se2 and α-Si based thin film solar cells. First, the photoluminescence of defect-related Cu(In,Ga)Se2 thin film solar cells show the donor-acceptor transition and band-impurity transition. The donor level and acceptor level can be extracted. The negative temperature coefficient of the short circuit current of Cu(In,Ga)Se2 solar cells may cause more degradation of power conversion efficiency at high temperature due to defects. In CIGS thin film solar cell standard process, it needs many patterning to complete process. The edge of the patterning is very rough and may have a lot of recombination in surface region. For the reason, atomic layer deposited (ALD) Al2O3 is used to passivated the CIGS and the effect of the passivation. For α-Si based solar cells, light-induced degradation is a significant issue. In order to investigate the lifetime of the α-Si based solar cells, we have to do reliability test.
47
Liu, Zhi-Hong, and 劉志鴻. "The Effect of Substrate Concentrations on Cis,Cis-Muconate Production from Benzoate by Pseudomonas sp." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/43052231740546749953.
Abstract:
碩士義守大學
生物技術與化學工程研究所
101
Muconic acid (MA) can be transformed to adipic acid by using the Pt as catalytic agent at 50 psi and room temperature. Adipic acid is an important raw material for producing plastics such as nylon 6,6 which is produced through chemical synthesis; however, that chemical manufacturing will cause a lot of greenhouse gases of NOx to be discharged during the process thus adding to the greenhouse effect. Energy consumption and environmental pollution can be reduced if white biotechnology is used to replace the chemical synthesis to produce the MA. Our laboratory obtained a bacterial strain from the sludge of industrial wastewater treament. The strain, identified to be Pseudomonas sp., has been mutated to a high-yield MA strain by chemical mutagens and proper screening strategy. We found the compositions of the complete medium by using the response surface methodology, further discussed the impacts of the mass transfer of oxygen in fermentation batch on the generation of MA, and the comparison of the compound nutrition assembly used in fed-batch cultivation. The goal of this study is to discuss how to improve the efficiency of product accumulation and cell growth after amplifying the MA procedure by adjusting the concentrations of substrate and improving the procedures. We studied the inhibition level of the product concentration on the MA produced by cells, the test found that the speed of cell growth was reduced by 40% and the productivity was decreased by 50% when the MA concentration was higher than 10g/L; and the cellular productivity could be improved to 1.2 g MA /g DCW/hr by keeping the dissolved oxygen value above 30% during transference of the benzoic acid to generate MA. In the aspect of procedural improvement, variable feeding is chosen to replace periodic feeding. It can not only improve the specific growth rate by 380%, but also increase the original productivity by 140%. In the aspect of substrate concentrations, the proper glucose concentration and C/N ratio are used to achieve the aims of cell growth and productivity improvement: When the glucose concentration is 10 g/L with 0.5 of C/N ratio, the specific growth rate can reach 0.63 hr-1 and the cellular productivity is 0.86 g MA /g DCW/hr. Finally, this process verifies that the addition of benzoic acid in the batch stage can induce the activity of the genes used to regulate and control the metabolism pathway of MA production in Pseudomonas sp., which is conducive to the accumulation of MA in the fed-batch fermentation.
48
Huang, Wei-Yuan, and 黃威元. "Effects of ZnS Material Parameters on CIGS Solar Cells." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/44018805603407012938.
Abstract:
碩士國立東華大學
電機工程學系
97
Some device properties of effects upon the performance of copper indium gallium diselenide solar cells are analyed by means of the device simulation tool of AMPS-1D (Analysis of Microelectronic and Photonic Structures). First, the modeling and material parameters of all layers in CIGS solar cells are established. The effects of doping density and thickness of various CdS buffer layer, bandgap energy of high-recombination interface, thickness of Cd-doping surface layer, and hole density, thickness, and electron and hole mobility of CIGS absorber on the CIGS solar cells. We also investigate how the material parameters affect the performance of CIGS solar cells. High-efficiency CIGS solar cells employ the CdS buffers layer typically. However, the use of cadmium is not accepted from the viewpoint of environmental safety. Cd-free buffer layers such as ZnS are the attractive alternative. CIGS solar cells with the ZnS buffer layers have higher quantum efficiency at short wavelengths, but Voc and FF are lower. The various electron affinity, thickness and doping density of ZnS buffer layer of CIGS solar cells are simulated by the device simulation tool of AMPS-1D. With the simulation results, the high-efficiency CIGS solar cells with the ZnS buffer could be achieved by applying the proper band alignment.
49
Liu, Yu-Wei, and 劉郁緯. "The Effect of Selenization Parameter on CIGS Solar Cell Absorber Layer." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/26781765088337059444.
Abstract:
碩士龍華科技大學
工程技術研究所
101
In this work, copper indium gallium diselenide (CIGS) solar cells were deposited on soda-lime glass substrates by two-step method. Firstly, the Cu/Ga/In alloy precursors of approximately 750 nm thickness were deposited sequentially on glass substrates using Cu–Ga alloy and In targets by direct current magnetic sputtering system. Secondly, the metallic precursors were then selenized (about 2 μm thick) with solid Se pellets in a closed vacuum furnace. To study the effect of annealing on the chalcopyrite CIGS structure properties, the films have been annealed in vacuum. The influence of various annealing process parameters (annealing temperature, chamber pressure, heating rate and holding time) on the structural, morphological and properties of CIGS films were investigated.
50
Hei-Sheng, Tsai, and 蔡輝昇. "A STUDY OF EFFECT FOR CHT CONDUCTION OF CIS." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/32049858240957576390.
Abstract:
碩士國立臺灣科技大學
工程技術研究所
86
Corporate Identity System (CIS) is a total communication system which contains mind identity, behavior identity and visual identity; meanwhile, CIS has become a powerful strategy for managing current enterprise successfully. In order to alter former conservative corporation image and to establish a new、cordial、sincere and effective image for enterprise, CHT conducts CIS formally when reorganized. This study applies objective and scientific method of investigation to predict effect of CHT conduction of CIS1. By the Interview Survey, we found out that due to there is no exclusive administrative department for building up enterprise image for CHT, CHT had difficulty of executing identification of organization；meanwhile, because of lack of sampling when making enterprise image, CHT had problems of deficiency, mistake and misuse of regulations. 2. Compared with other private telecommunications companies, CHT had a negative comment of conservation, however, CHT also got positive appraise with powerful enterprise character and made internationally magnificent performance.3. The Questionnaire Survey shows that the investigated people are sure of that the effect of CHT conducting of corporation identification. 4. After reviewing the research, it is no doubt that the factors affecting the effect of use of CIS are emotional、rational、traditional and modern concepts, these parts play important roles and influence others mutually. The main cause influencing recognizing of particular styling (Mascots) is because of the design of corporation mark、 the characteristics of professions and the attributes of enterprises. Therefore, CI offers opportunities for enterprise to deliberate、evaluate and design strategies for im5. This study utilizes the modified method of SD for finding out the efficiency of conducting CI. Is the modified method more effective or not depends on further detailed and long researches for verification.