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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
561

TRPV4-TRPC1- BKca tri-complex mediates epoxyeicosatrienoic acid-induced membrane hyperpolarization. / Transient receptor potential vanilloid 4- transient receptor potential channel 1- large conductance calcium activated potassium channels tri-complex mediates epoxyeicosatrienoic acid-induced membrane hyperpolarization / CUHK electronic theses & dissertations collection

January 2011 (has links)
Ma, Yan. / "Ca" in the title is subscript. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 143-166). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.
562

Le ferrate (VI) de potassium : optimisation de sa synthèse par voie hétérogène à une échelle semi-industrielle et applications au traitement des eaux, de polluants modèles aux effluents réels / Potassium ferrate (VI) : optimization of its semi-industrial synthesis by heterogeneous method and applications for water treatments, from model pollutants to real effluents

Vanessa, Peings 17 December 2014 (has links)
Le ferrate (VI) de potassium est un produit prometteur dans la filière du traitement des eaux de par ses propriétés oxydantes, coagulantes et désinfectantes. S’il n’est pas largement employé aujourd’hui, c’est à cause de son coût de production. Un objectif majeur de ce travail est de développer la synthèse du ferrate (VI) au sein du sel double K2(Fe0,5,S0,5)O4 solide et stable. L’étude de la synthèse à l’échelle du laboratoire a permis de comprendre les mécanismes physico-chimiques régissant la synthèse et d’établir un cahier des charges pour la conception d’un pilote semi-industriel. En l’état actuel des recherches, un produit contenant 28-34% de K2(Fe0,5,S0,5)O4 est obtenu. L’étude de l’action du ferrate (VI) sur des molécules organiques (pharmaceutiques, toxines, bactéries…) et inorganiques (cyanures, métaux…) a été réalisée. Un mécanisme d’oxydation par transfert électronique à 1 électron a été observé lors du traitement du phénol. Le potentiel du produit à être utilisé pour une dépollution de l’eau est confirmé sur des polluants modèles et sur des effluents réels et lui assure un large domaine d’application. / Potassium ferrate (VI) is a new challenging product in the field of water treatment. The world interest in this high-valent iron is explained by its properties of chemical oxidant, coagulant and disinfectant. However, high cost of its production restricts its big scale applications. Thus, the main objective of this study is focused on ferrate synthesis in a solid form more stable K2(Fe0,5,S0,5)O4. At first, synthesis has been developed at lab scale to improve understanding of its mechanisms and define the conception of a small industrial pilot. At the moment, a product with 28-34% of K2(Fe0,5,S0,5)O4 is obtained. The removal of organics (pharmaceuticals, toxins, bacteria…) and inorganics (cyanides, metals…) in water by ferrate (VI) has been explored. An oxidation mechanism which consists in a single electron transfer has been highlighted for phenol treatment. Finally, the results confirm the real ability of the product synthesized to treat both contaminants in water and industrial effluents.
563

Modulation of porcine coronary artery BKCa and IKATP channels gatings by 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase inhibitor. / Modulation of porcine coronary artery on calcium-activated and ATP-sensitive potassium channels gatings by 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase inhibitor / CUHK electronic theses & dissertations collection

January 2008 (has links)
3-Hydroxy-3-Methylglutaryl Coenzyme A (HMG CoA) reductase is a 97 kDa glycoprotein located in the endoplasmic reticulum responsible for cholesterol biosynthesis in mammalian liver and intestine. HMG CoA reductase inhibitors (statins) (e.g. simvastatin, mevastatin and parvastatin) are used clinically to treat and prevent coronary artery diseases by reducing plasma LDL-cholesterol level. Recent studies have demonstrated that statins can provide beneficial effects (pleiotropic effects) beyond its lipid-lowering activity. However, the modulatory effects of statins on ion channels activities have not been fully explored. Hence, this study is designed to demonstrate the existence of the HMG CoA reductase in various human isolate cardiovascular preparations and the modulatory effect(s) of simvastatin on both large-conductance calcium-activated (BKCa) and ATP-sensitive (IKATP) potassium channels of porcine isolated coronary vascular smooth muscle cells. / In conclusion, our results demonstrated the biochemical existence of HMG CoA reductase in various human isolated cardiovascular preparations and porcine isolated coronary artery. Simvastatin modulates the BKCa and IKATP channels of the porcine isolated coronary artery via different and multiple cellular mechanisms. / In this study, we demonstrated the biochemical existence of the HMG CoA reductase in various human isolated cardiovascular preparations and porcine isolated coronary artery. In addition, we demonstrated that simvastatin modulates both the BKCa channels and IKATP channels of porcine isolated coronary artery via different mechanisms. Acute application of simvastatin (100 nM) slightly enhanced whereas simvastatin (≥ 1 muM) inhibited the BKCa amplitude of porcine coronary artery smooth muscle cells. The classical HMG CoA reductase-mevalonate cascade is important in mediating the inhibitory effect of simvastatin observed at low concentrations (1 and 3 muM), whereas an increased PKC-delta protein expression and activation is important in simvastatin (10 muM)-mediated inhibition of BKCa channels. In contrast, the basal activity of the IKATP channels was not affected by simvastatin (1, 3 and 10 muM). However, acute application of simvastatin (1, 3 and 10 muM) inhibited the opening of the IKATP channels by cromakalim and pinacidil in a PP2A-dependent manner (sensitive to okadaic acid, a PP2A inhibitor). The okadaic acid-sensitive, simvastatin-mediated inhibitory effect on IKATP channel is mediated by an activation of AMPK in a Ca2+-dependent manner. Activation of AMPK probably increased the activity of the Na+/K+ ATPase and subsequently caused an influx of glucose via the SGLT1 down the Na + concentration gradient for the ouabain-sensitive, glucose-dependent activation of PP2A. / Seto, Sai Wang. / Adviser: Yiu-Wa Kwan. / Source: Dissertation Abstracts International, Volume: 70-06, Section: B, page: 3456. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 221-254). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.
564

Effect of hyperkalemia and ischemia on large conductance calcium-activated potassium channels in porcine coronary arterial smooth muscle: relevance to cardioplegic arrest. / 高鉀和缺血對豬冠狀動脈平滑肌大電導鈣激活鉀通道的影響--與心臟手術的相關性 / Gao jia he que xue dui zhu guan zhuang dong mai ping hua ji da dian dao gai ji huo jia tong dao de ying xiang -- yu xin zang shou shu de xiang guan xing

January 2008 (has links)
Han, Jianguo. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 66-76). / Abstracts in English and Chinese. / Declaration --- p.i / Acknowledgement --- p.□ / Publication --- p.□ / Abstract (English) --- p.□xi / Abstract (Chinese) --- p.□ / Abbreviations --- p.ix / List of figures / tables --- p.x / Chapter Chapter 1. --- General Introduction / Chapter 1.1 --- Role of vascular smooth muscle cells in the control of coronary circulation --- p.1 / Chapter 1.1.1 --- Potassium channels in the coronary smooth muscle cells --- p.2 / Chapter 1.1.1.1 --- Voltage -dependent potassium (Kv) channels --- p.3 / Chapter 1.1.1.2 --- Inward rectifier K+ (Kir) channels --- p.4 / Chapter 1.1.1.3 --- ATP-sensitive potassium (Katp) channels --- p.4 / Chapter 1.1.2 --- BKCa channels in the regulation of vascular function --- p.6 / Chapter 1.1.2.1 --- The structure of BKCa channels --- p.6 / Chapter 1.1.2.2 --- Role of BKCa channels in the regulation of vascular function --- p.6 / Chapter 1.2 --- Functional alteration of the coronary SMCs during cardiac surgery --- p.7 / Chapter 1.2.1 --- Effect of ischemia on the function of SMCs in the coronary circulation --- p.8 / Chapter 1.2.2 --- Effect of cardioplegic/organ preservation solutions on the function of SMCs in the coronary circulation --- p.11 / Chapter Chapter 2. --- Materials and Methods --- p.14 / Chapter 2.1 --- Isometric force study in small coronary arteries --- p.14 / Chapter 2.1.1 --- Preparation of porcine small coronary arteries --- p.14 / Chapter 2.1.2 --- Experiment procedure --- p.15 / Chapter 2.1.2.1 --- Mounting of small coronary arteries --- p.15 / Chapter 2.1.2.2 --- Normalization procedure for small coronary arteries --- p.16 / Chapter 2.1.2.3 --- Precontraction and relaxation --- p.17 / Chapter 2.1.3 --- Data acquisition and analysis --- p.17 / Chapter 2.2 --- Patch-clamp electrophysiology --- p.18 / Chapter 2.2.1 --- Preparation of porcine coronary arteries --- p.18 / Chapter 2.2.2 --- Enzymatic dissociation of coronary arterial SMCs --- p.18 / Chapter 2.2.3 --- Primary cell culture --- p.19 / Chapter 2.2.4 --- Recording of BKca channel currents --- p.19 / Chapter 2.3 --- Statistical analysis --- p.21 / Chapter 2.4 --- Chemicals --- p.21 / Chapter Chapter 3. --- The Effect of Ischemia on BKCa channels in the Isolated SMCs of Coronary Arteries --- p.22 / Chapter 3.1 --- Abstract --- p.22 / Chapter 3.2 --- Introduction --- p.23 / Chapter 3.3 --- Experimental design and analysis --- p.25 / Chapter 3.3.1 --- Isometric force study in small coronary arteries --- p.25 / Chapter 3.3.2 --- Effect of ischemia on NS1619-induced relaxation in small coronary arteries --- p.26 / Chapter 3.3.3 --- Effect of ischemia on smooth muscle BKca channel currents --- p.27 / Chapter 3.3.3.1 --- Preparation of porcine coronary artery --- p.27 / Chapter 3.3.3.2 --- Enzymatic dissociation of coronary arterial SMCs --- p.27 / Chapter 3.3.3.3 --- Recording of BKCa channel currents --- p.27 / Chapter 3.3.4 --- Data acquisition and analysis --- p.28 / Chapter 3.4 --- Results --- p.28 / Chapter 3.4.1 --- Electrophysiological studies --- p.28 / Chapter 3.4.1.1 --- Effect of IBTX on the whole cell outward currents --- p.29 / Chapter 3.4.1.2 --- Effect of ischemia on the IBTX-sensitive BKca currents --- p.30 / Chapter 3.4.2 --- Relaxation studies --- p.30 / Chapter 3.4.2.1 --- Resting force --- p.30 / Chapter 3.4.2.2 --- U46619-induced contraction force --- p.31 / Chapter 3.4.2.3 --- Effect of IBTX on the NS1619-induced relaxation --- p.31 / Chapter 3.4.2.4 --- Effect of ischemia on the NS1619-induced relaxation --- p.31 / Chapter 3.5 --- Discussion --- p.32 / Chapter 3.5.1 --- Functional changes of the coronary smooth muscle BKca channels after ischemic exposure --- p.33 / Chapter 3.5.2 --- Role of BKca channels in SMCs during ischemia --- p.33 / Chapter 3.5.3 --- Clinical implications --- p.35 / Chapter Chapter 4. --- The Effect of Hyperkalemia on BKCa channels in the Isolated SMCs of Coronary Arteries --- p.41 / Chapter 4.1 --- Abstract --- p.41 / Chapter 4.2 --- Introduction --- p.42 / Chapter 4.3 --- Experimental design and analysis --- p.44 / Chapter 4.3.1 --- Isometric force study in small coronary arteries --- p.44 / Chapter 4.3.1.1 --- Effect of hyperkalemia on NS1619-mediated relaxation in small coronary arteries --- p.44 / Chapter 4.3.2. --- Effect of hyperkalemia on BKCa currents of SMCs --- p.45 / Chapter 4.3.2.1 --- Preparation of porcine coronary arteries --- p.45 / Chapter 4.3.2.2 --- Enzymatic dissociation of coronary arterial SMCs --- p.45 / Chapter 4.3.2.3 --- Recording of BKca channel currents --- p.46 / Chapter 4.3.3. --- Data acquisition and analysis --- p.46 / Chapter 4.4 --- Results --- p.47 / Chapter 4.4.1 --- Effect of hyperkalemia on the iberiotoxin-sensitive BKCa channel currents --- p.47 / Chapter 4.4.2 --- Relaxation studies --- p.48 / Chapter 4.4.2.1 --- Resting force --- p.48 / Chapter 4.4.2.2 --- U46619- and high K+-induced contraction force --- p.48 / Chapter 4.4.2.3 --- Effect of high K+ on the NS1619-induced relaxation --- p.48 / Chapter 4.4.2.4 --- Effect of IBTX on the NS1619-induced relaxation --- p.49 / Chapter 4.5 --- Discussion --- p.49 / Chapter 4.5.1 --- Role of BKCa channels in the isolated SMCs in hyperkalemic solution --- p.50 / Chapter 4.5.2 --- Functional changes of BKCa channels in coronary SMCs in hyperkalemia exposure --- p.51 / Chapter 4.5.3 --- Clinical implications --- p.52 / Chapter Chapter 5. --- General Discussion --- p.58 / Chapter 5.1 --- BKCa channels in porcine coronary SMCs --- p.59 / Chapter 5.2 --- Alteration of BKCa function related to ischemia in porcine coronary SMCs --- p.60 / Chapter 5.3 --- Alteration of BKCa function related to hyperkalemia in porcine coronary SMCs --- p.61 / Chapter 5.4 --- Limitation of the study --- p.62 / Chapter 5.5 --- Future investigations --- p.63 / Chapter 5.6 --- Conclusions --- p.63 / References --- p.66
565

Amélioration de la tenue au flux laser des composants optiques du laser Mégajoules par traitement chimique / Laser-induced damage resistance improvement of fused silica optics by wet etching process.

Pfiffer, Mathilde 17 October 2017 (has links)
Cette thèse porte sur l’amélioration de la résistance au flux laser de la surface descomposants optiques en silice en régime nanoseconde. Ce matériau est utilisé sur lesinstallations de laser de puissance telles que le Laser Mégajoule. Pour augmenter la durée de viedes composants optiques et garantir le fonctionnement nominal de cette installation,l’endommagement laser doit être maîtrisé. Il s’agit d’une dégradation irréversible de la surfacedes composants causée par l’interaction entre le faisceau laser et des défauts précurseurs. Cesderniers sont une conséquence de la synthèse de la silice puis du polissage des composants etleur présence peut être limitée par une action de traitement chimique réalisée à l’issue dupolissage qui consiste à éroder la surface de silice à l’aide d’une solution chimique. Cette érosionne doit cependant pas dégrader la qualité de la surface polie et ses propriétés optiques. Cettethèse se concentre sur la réalisation de cette étape de traitement chimique et se décompose entrois études. La première porte sur la caractérisation de la pollution induite en surface par lepolissage et sa suppression par le traitement chimique. La seconde et la troisième analysentl’impact des traitements chimiques respectivement sur les propriétés optiques de la surface etsur les rayures de polissage. Ces études nous permettent d’évaluer l’influence des différentsparamètres du traitement chimique, tels que la solution, le système de mise en oeuvre etl’épaisseur érodée, sur les performances apportées aux composants optiques. Finalement,l’ensemble de ces connaissances nous conduit à proposer un traitement chimique optimisé quiaméliore la tenue au flux des composants optiques sans dégrader leurs propriétés optiques. / In this thesis, laser-induced damage resistance improvement of fused silica opticsis investigated in the nanosecond regime. This material is used on high power laser facilitiessuch as the Laser Mégajoule. In order to improve the optics life time and to ensure the nominaloperation of this facility, laser induced damage has to be controlled. This phenomenon is anirreversible modification of the components surface because of the interaction between the laserbeam and precursors defects. These defects are a consequence of the synthesis of silica and thepolishing of the optics and their presence can be reduced by a wet etching. This process consistsin an erosion of the surface using a chemical solution however optical properties must remainunchanged. In this thesis, we focus on the wet etching process and we conduct three studies. Thefirst one is about the characterization of the polishing induced contamination and the capabilityof a wet etching to remove it from the surface. The second and the third analyzes are about theimpact of the wet etching respectively on the surface and on the scratches. These studies allowus to evaluate the influence of the wet etching parameters as the chemical solution, the systemused and the deep etched. Finally, the highlights obtained thanks to these studies enable tooptimize the wet etching process and improve the laser induced damage resistance ofcomponents without compromising their optical properties.
566

Effect of KCNE1 and KCNE3 Accessory Subunits on KCNQ1 Potassium Channel Function: A Dissertation

Rocheleau, Jessica Marie 02 December 2008 (has links)
The KCNE1 and KCNE3 type I transmembrane-spanning β-subunits assemble with the KCNQ1 voltage-gated K+ channel to afford membrane-embedded complexes with dramatically different properties. Assembly with KCNE1 produces the very slowly activating and deactivating IKs current that shapes the repolarization phase of cardiac action potentials. Genetic mutations in KCNQ1 or KCNE1 that reduce IKs current cause long QT syndrome and predispose affected individuals to potentially fatal cardiac arrhythmias. In contrast, complexes formed between KCNQ1 and KCNE3 produce rapidly activating and mostly voltage-independent currents, properties that are essential for function in K+ recycling and Cl−secretion in gastrointestinal epithelia. This thesis addresses how these two homologous accessory peptides impart their distinctive effects on KCNQ1 channel gating by examining two important protein regions: 1) a conserved C-terminal motif in the β-subunits themselves, and 2) the voltage sensing domain of KCNQ1 channels. Sequences in both the transmembrane domain and C-terminus of KCNE1 and KCNE3 have been identified as contributing to the divergent modulatory effects that these β-subunits exert. The homology of transmembrane-abutting C-terminal residues within the KCNE family and the presence of long QT-causing mutations in this region highlight its importance. A bipartite model of modulation was proposed that suggests the transmembrane domain of KCNE1 is passive, allowing the C-terminal domain to control modulation. Chapter II builds on this model by investigating the effect of mutating specific amino acids in the KCNE1 C-terminal domain. Point mutants that produce ‘high impact’ perturbations in gating were shown to cluster in a periodic fashion, suggesting an alpha-helical secondary structure that is kinked by a conserved proline residue and interacts with the Q1 channel complex. In Chapter III, the voltage sensing domain of Q1 channels is examined in the presence of either KCNE1 or KCNE3. To determine the influence of these two peptides on voltage sensing, the position of the S4 voltage sensor was monitored using cysteine accessibility experiments. In the slowly opening KCNQ1/KCNE1 complexes, voltage sensor activation appears to occur much faster than the onset of current, suggesting that slow channel activation is not due to slowly moving voltage sensors. KCNE3, on the other hand, shifts the voltage sensor equilibrium to favor the active state, producing open channels even at negative voltages. Taken together, these findings provide mechanistic detail to illustrate how two homologous peptides radically alter the gating properties of the same K+ channel and present a structural scaffold to map protein-protein interactions.
567

Nitrogênio e potássio em cobertura na nutrição e produtividade do alho vernalizado livre de vírus e qualidade do alho minimamente processado / Yield and mineral nutrition of garlic in response to source of nitrogen and sources of potash and quality changes in fresh-peeled garlic

Tanamati, Fábio Yomei [UNESP] 02 June 2016 (has links)
Submitted by FÁBIO YOMEI TANAMATI null (fabioyomei@hotmail.com) on 2016-12-21T18:02:23Z No. of bitstreams: 1 Tese- Fábio Final.pdf: 1752648 bytes, checksum: f9b77e3ee591fdbadfb4e16551e1bfc3 (MD5) / Approved for entry into archive by Felipe Augusto Arakaki (arakaki@reitoria.unesp.br) on 2016-12-22T13:34:23Z (GMT) No. of bitstreams: 1 tanamati_fy_dr_bot.pdf: 1752648 bytes, checksum: f9b77e3ee591fdbadfb4e16551e1bfc3 (MD5) / Made available in DSpace on 2016-12-22T13:34:23Z (GMT). No. of bitstreams: 1 tanamati_fy_dr_bot.pdf: 1752648 bytes, checksum: f9b77e3ee591fdbadfb4e16551e1bfc3 (MD5) Previous issue date: 2016-06-02 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O alho é uma hortaliça utilizada como condimento e como planta medicinal. O Brasil é um importante produtor/consumidor desta hortaliça, entretanto a produção nacional é insuficiente e portanto importa de quase 60% do alho consumido. Práticas precisas de manejo na produção e pós-colheita precisas podem resultar em economia na produção, aumento da produtividade e qualidade. Entre as práticas de manejo destaca-se a fertilização destaca-se pela influência direta na produção do alho e constituir um dos principais itens do custo de produção. Após a colheita a deterioração do alho minimamente processado (produto com maior valor agregado) pode ser diminuída através do armazenamento em temperatura controlada e atmosfera modificada. Com o objetivo de avaliar e documentar as melhores fontes e doses de nitrogênio e fontes potássio, bem como o melhor método para o armazenamento do alho minimamente processado foram conduzidos três ensaios que serão apresentados em três capítulos, sendo o primeiro intitulado “Fontes de nitrogênio e potássio sob a produtividade e nutrição mineral do alho”, o segundo capítulo intitulado “Produtividade e nutrição mineral do alho sob diferentes doses de nitrogênio e fontes de potássio”, e o terceiro capítulo intitulado “Efeito de diferentes temperaturas e atmosfera modificada sob as características qualitativas do alho minimamente processado”. Concluiu- se a) Diferentes fontes de N e K podem ser combinadas para a obtenção de máxima produção de alho comercial, b) o teor de nutrientes do alho não é influenciado pelas fontes de N e K ao ponto de constituir um fator crítico à produtividade do alho, c) Recomenda-se a dose 80 kg ha -1 de N como forma de obtenção de máxima eficiência do fertilizante e produtiva do alho vernalizado livre de vírus cv. Caçador, d) Não houve diferenças significativas na produção do alho acima da dose 80 kg ha -1 de N, a partir desta dose, o acúmulo de nutrientes no bulbo, de forma geral, foi inferior nos tratamentos K2SO4, e) baixa temperatura e atmosfera modificada contribuem significativamente para a manutenção da qualidade do alho minimamente processado, f) embalagem a vácuo mantém uma atmosfera consistentes em uma maior gama de temperaturas, g) as atmosferas modificadas com alto teor de CO2 podem influenciar a diminuição do valor de L* durante o armazenamento, h) a pungência do alho é mais bem conservada em embalagens a vácuo. / Garlic is used as a spice and as a medicinal plant, Brazil is an important producer/ consumer of this herb, however small domestic production stimulates import of about 60% the garlic consumed in this country. Management practices in the production and accurate post-harvest can result in savings in production and increasing in yield and quality. Among the management practices, fertilization is distinguished by its direct influence on the production of garlic and constitute one of the main cost items of production and postharvest deterioration of minimally processed garlic (product with higher added value) can be reduced by storing in controlled and modified atmosphere temperature. In order to assess and document the best sources and doses of nitrogen and potassium sources, as well as the more suitable storage method for fresh-peeled garlic we carried out three tests that will be presented in three chapters, the first entitled "Yield and mineral nutrition of vernalized virus free garlic in response to nitrogen and potassium sources topdressing" the second chapter entitled "Yield and mineral nutrition of garlic in response to nitrogen doses and potassium sources topdressing”, "Quality changes in fresh-peeled garlic cloves in relation to storage temperatures and modified atmospheres". From these assays we concluded that a) Different sources of N and K may be combined to obtain maximum production of commercial garlic, b) the garlic mineral content is not influenced by the sources of N and K to be considered a critical factor to garlic productivity, c) 80 kg ha -1 of N is the best way to obtain both maximum fertilizer efficiency and productive of virus free vernalizated garlic cultivar Caçador, d) from the dose 80 kg ha -1 , the lowest accumulation of nutrients in the bulb in SKO treatments suggests that potassium sulfate, alleviates possible effects of toxicity caused by excess NH4 + and reduces minerals export for bulb and thereby the ground, e) both low temperature and modified atmosphere significantly contribute to the maintenance of the quality of fresh-peeled garlic, f) vacuum packaging maintains an atmosphere consistent across a wider range of temperatures, g) modified atmospheres with high CO2 content can influence the decrease in L* value during storage, h) garlic pungency is better preserved in vacuum packaging.
568

Caractérisation du transport moléculaire vésical : applications cliniques et pharmacologiques / Characterization of molecular transport through the bladder : clinical and pharmacological applications

Moch, Céline 14 February 2014 (has links)
Les pathologies vésicales sont nombreuses et nécessitent la plupart du temps un traitement médicamenteux. Il peut alors être administré par voie intravésicale, augmentant son efficience et limitant les effets indésirables systémiques. Nous nous sommes intéressés à quatre thérapeutiques : l’alun de potassium, le chlorhydrate de lidocaïne, l’hemisuccinate de méthylprednisolone, la mitomycine C et le bacille de Calmette et Guérin (BCG) en application locale directement dans la vessie. La perméabilité de l’aluminium à travers la vessie a été étudiée au travers d’un cas clinique et des expériences ex vivo ont été réalisées pour définir les paramètres de perméabilité et proposer un algorithme de prédiction de la quantité d’aluminium absorbée dans l’organisme après irrigation intravésicale à l’alun de potassium. Cet algorithme dépend du poids du patient, de la durée de l’irrigation et du volume de la solution utilisée en irrigation vésicale. Des études de perméation ont aussi été réalisées pour le chlorhydrate de lidocaïne, l’hemisuccinate de méthylprednisolone, la mitomycine C et le BCG afin de sécuriser l’emploi de ces thérapeutiques par voie intravésicale. Les études réalisées permettent de prédire, selon les caractères physico-chimiques des molécules, la pénétration dans la membrane vésicale. Une nouvelle formulation galénique réalisée à base d’un gel thermosensible a été étudiée pour optimiser les thérapeutiques intravésicales. Des études de perméation ont été faites avec la nouvelle formulation galénique. Pour finir, une culture de cellules cancéreuses urothéliales a été mise au point et un test de viabilité a été réalisé pour la mitomycine C et le BCG / Bladder diseases are numerous and mostly require medication. Drugs can be administered by intravesical route, thereby increasing efficiency and reducing systemic side effects. We are interested in four drugs: potassium alum, lidocaine hydrochloride, methylprednisolone hemisuccinate, mitomycin C and bacillus Calmette- Guérin (BCG). Mathematical modelling of drug transport through bladder wall is proposed considering scarce literature on this route of administration. The permeability of aluminum through bladder wall was studied through a clinical case and ex vivo experiments were performed to propose a simplified algorithm for the calculation of aluminium dose absorbed in patient with impaired renal function as function of volume of 1% alum solution in the bladder, duration of intravesical irrigation and patient body weight. Permeation studies were also conducted for lidocaine hydrochloride, methylprednisolone hemisuccinate, mitomycin C and BCG to secure intravesical administration of these drugs. Practical outcome of this study could drive compounding optimisation towards improvement of safety and efficacy in patient undergoing intravesical administration. A new pharmaceutical formulation including hrydrogel has been studied in an attempt to improve treatment administered by intravesical route. Permeation studies were made with the new formulation. Finally, an urothelial cancer cells culture has been developed and a viability test was performed with mitomycin C and BCG
569

Mise en évidence et rôle potentiel des canaux potassium ATP-dépendants dans la fonction de reproduction

Lybaert, Pascale 10 June 2009 (has links)
Parmi les différents types de canaux ioniques, les canaux potassium (K+) sont très largement exprimés au niveau des cellules eucaryotes. Ils se répartissent en plusieurs familles et sous-familles. Parmi celles-ci, les canaux K+ ATP-dépendants (KATP) représentent une classe tout à fait particulière. En effet, ils ont la particularité d’être sensibles à la concentration cytosolique d’ATP et permettent ainsi de coupler le potentiel membranaire de la cellule à son statut métabolique.<p>Le canal KATP est un complexe hétéro-octamérique constitué de 2 sous-unités :une sous-unité Kir6.x (Kir6.1 ou Kir6.2) formant le pore du canal et appartenant à la famille des canaux potassiques de type « inward rectifier », et une sous-unité régulatrice SURx (SUR 1 ou SUR2A/B) faisant partie des protéines ABC (ATP-binding cassette). L’expression hétérologue des sous-unités Kir6.x et SURx suivant différentes combinaisons conduit à la formation de plusieurs types de canaux KATP possédant des propriétés électro-physiologiques et des sensibilités aux nucléotides et aux agents pharmacologiques distinctes. \ / Doctorat en sciences biomédicales / info:eu-repo/semantics/nonPublished
570

Surface composition of cobalt catalysts for steam reforming of ethanol / Étude de la composition de la surface des catalyseurs à base de cobalt pour le reformage des vapeurs d'éthanol

Turczyniak, Sylwia 28 September 2016 (has links)
L’objectif de cette thèse de doctorat a consisté à déterminer l’influence des conditions réactionnelles du vaporeformage de l’éthanol (ESR), de la dispersion du catalyseur et de la promotion par le potassium sur l’état de la surface. Ce travail a aussi aidé à comprendre l’influence de ces facteurs sur les propriétés catalytiques. Nous avons utilisé les catalyseurs à base de cobalt (promus et non promus par le potassium) supportés à l’oxyde de cérium et à l’oxyde de zirconium à faible et à forte dispersion. Les changements de l’état de la surface des catalyseurs pendant la réaction d’ERS ont été étudiés à travers la spectrométrie photoélectronique X (XPS), alors que les changements des produits ont été analisés en utilisant la spectrométrie de masse et la chromatographie en phase gazeuse. Le catalyseur supporté sur oxyde de cérium à forte dispersion a été caractérisé sous une basse pression (0.2-20 mbar) avec le rapport molaire eau/éthanol de 3/1 (420ºC). Les autres tests ont été faits sur tous les catalyseurs sous une pression totale de 1 atm avec les rapports molaires de 3/1, 9/1, 12/1 (420ºC). Nous avons utilisé un mélange eau/éthanol dans un rapport molaire de 12/1 pour étudier les changements de l’état de la surface de tous les catalyseurs dans le temps. Il a été démontré que la sélectivité d’ESR des catalyseurs pour produire des gaz et pour déposer le carbone est réglée par la concentration des groupes hydroxyles sur la surface. Quant aux catalyseurs promus, elle dépend aussi de la concentration Kδ+–Osurfδ-. / The aim of the thesis was determination the influence of the ethanol steam reforming (ESR) reaction conditions, catalyst’s dispersion and potassium promotion on a surface’s composition and understanding the influence of these changes on catalysts’ performance. Cobalt-based catalysts (unpromoted and promoted with potassium) with low- and high-dispersed ceria and zirconia supports were used. The changes of the surface state of catalysts during the ESR were studied by means of X-ray photoelectron spectroscopy, whereas the reaction products evolution was followed by mass spectrometer or gas chromatograph. Highly-dispersed ceria-supported catalyst was characterized under low pressure conditions (0.2–20 mbar) with the water/ethanol molar ratio equal to 3/1 (at 420ºC). The other tests were carried out over all catalysts under total pressure of 1 atm with 3/1, 9/1 and 12/1 molar ratios (at 420ºC). The water/ethanol ratio of 12/1 was chosen for studies of the surface state of all catalysts with time-on-stream. It was found that the ESR selectivity to gaseous products and carbon deposition is governed mainly by surface hydroxyl species concentration; in the promoted catalysts together with Kδ+–Osurfδ- surface sites.

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