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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.
71

Nardilysin in adipocytes regulates UCP1 expression and body temperature homeostasis / 脂肪細胞のナルディライジンはUCP1の発現と体温恒常性を調節する

Saijo, Sayaka 23 May 2022 (has links)
京都大学 / 新制・論文博士 / 博士(医学) / 乙第13490号 / 論医博第2258号 / 新制||医||1059(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 渡邉 大, 教授 稲垣 暢也, 教授 長船 健二 / 学位規則第4条第2項該当 / Doctor of Medical Science / Kyoto University / DFAM
72

Experimental substructuring of an A600 wind turbine blade  : A study of the influence of interface loading

Santos, Judas, Al-Mahdi, Nidaa January 2016 (has links)
Dynamic Substructuring is a powerful tool for simplification of the analysis of complex structures and it has been well established along the years in analytical calculations by means of the Craig-Bampton technique. Recently, a new branch of substructuring, the Experimental Dynamic Substrucuring, appeared as a promising field of research for the engineering community. This area presents several intrinsic difficulties, evincing a need to develop the traditional substructuring methods towards obtaining better results using the experimental approach. In this scenery, the Transmission Simulator technique emerges as an instrument for potential improvement of the achieved results. This work represents a study on the use of the Transmission Simulator technique in the analysis of an Ampair A600 wind turbine blade subjected to loads at the interface to the hub, and it is a part of the benchmarking studies of SEM (Society of Experimental Mechanics). The work consisted of collecting experimental data via vibration tests of a single blade connected to different sizes of transmission simulators. After that, a mathematical representation of the blade was obtained via subtraction of the effect of the transmission simulators via substructuring technique. The computed model was subsequently coupled to a model of the remainder of the wind turbine (the hub plus two blades), and the results were compared to data acquired in tests of the whole assembly. The final findings did not reflect the theory prospects and further investigation is necessary to evaluate the effectiveness of the used methodology.
73

Distribuce mitochondriálních odpřahujících proteinů ve vybraných tkáních myši a potkana / Distribution of mitochondrial uncoupling proteins in selected tissues from mice and rat

Alán, Lukáš January 2010 (has links)
Mitochondrial uncoupling proteins (UCPs) belong to the superfamily of mitochondrial anion-carriers. The longest known is UCP1, predominantly expressed in brown adipose tissue, where it takes part in nonshivering thermogenesis. In the late 1990s were discovered other sequence homologs of UCP1 with tissue specific distribution. The Function of these "new" uncoupling proteins is still uncertain. It is assumed that each of the isoforms has a specific function depending on the type of tissue. This thesis showed differences in tissue transcription pattern between rat and mice using RT-PCR absolute quantification. Significant differences in pattern were found in lungs, brain and muscle. In each case UCP expression was higher in mice tissues. Mice lungs express mainly UCP2. The difference in mice brain is caused by ucp4 and ucp5 genes transcription and finally in muscle is highest content of UCP3 mRNA. We investigated whether any of ucp transcript can complement ucp2 transcripton in spleen or lungs of ucp2 -/- mice. We did not find any difference which can explain, that in isolated lung mitochondria of fasted ucp2-/- mice were uncoupled in state 4. In the last project, we found relationship between ucp2 transcription in insulinoma INS-1E cells and oxygen levels of the cultivation atmosphere.
74

Význam metabolismu tukové tkáně pro celotělovou energetickou rovnováhu / Importance of adipose tissue metabolism for whole-body energy balance

Zouhar, Petr January 2015 (has links)
Adipose tissue plays a crucial role in nutrient and energy homeostasis. At the time of worldwide pandemy of obesity and consequent metabolic syndrome, a great effort is made to find new treatments with potential to preserve insulin sensitivity, or even counteract development of obesity and type 2 diabetes. There are three principal possibilities how the adipose tissue biology can contribute to this goal: 1) induction of UCP1-dependent energy dissipation in brown adipose tissue; 2) conversion of white adipose depots to brown-like tissue (i.e. "browning"); and 3) stimulation of UCP1-independent thermogenesis in white adipose tissue. This thesis is based on two published works and one article under preparation. Generaly, it is focused on three different approaches targeting the above mentioned processes in adipose tissue of laboratory mouse: 1) diet supplementation with bile acids; 2) combination treatment of ω-3 polyunsaturated fatty acids and calorie restriction; and 3) cold exposure. In the experiments with administration of bile (specifically chenodeoxycholic) acid to mice, we confirm specific induction of UCP1 in both brown and subcutaneous white adipose tissue, as well as reversion of obesity in the response to the treatment. Nevertheless, most of the acute beneficial effects are mediated by...
75

Detecção de adutos de trans,trans-2,4-decadienal em citocromo c. Efeitos em mitocôndrias isoladas / Detection of trans,trans-2,4-decadienal adducts in cytochrome c. Effects on isolated mitochondrial functions

Sigolo, Carlos Alexandre Oliveira 28 September 2007 (has links)
A atividade biológica de aldeídos α,Β-insaturados tem sido associada a diversos processos incluindo regulação gênica, envelhecimento Alzheimer e disfunções mitocondriais. Neste trabalho investigamos a formação de adutos do trans,trans-2,4-decadienal (DDE), um aldeído produzido endogenamente e presente como contaminante em alimentos e água, em lisina, histidina e citocromo c. Avaliamos também alterações na função de mitocôndrias de fígado de rato expostas ao aldeído. As análises por espectrometria de massas, LC-ESI/MS, indicaram a formação de diversos tipos de adutos de DDE nos aminoácidos lisina e histidina, entre eles bases de Schiff e enaminas. Os resultados obtidos por espectrometria de massas, MALDI-Tof, indicaram a formação de adutos de DDE formados via base de Schiff de maneira concentração do aldeído, tempo e pH dependentes. As análises da proteína digerida por ESI-Q-ToF, indicaram que os adutos foram formados nos resíduos H-33, K-39, 72 e 100, localizados em regiões ricas em resíduos básicos, cuja interação com membranas e citocromo e oxidase tem sido postulada. Observamos também o deslocamento da banda Soret (λ = 409 nm) e o desaparecimento da banda em λ = 695 nm, relativa a coordenação do sexto ligante do grupo heme (M-80). Este fenômeno está associado a abertura da cavidade do grupo heme e o deslocamento do ligante, indicando alterações nas estruturas secundária e terciária da proteína. Os experimentos realizados com mitocôndrias isoladas indicaram que DDE promove danos à membrana interna mitocondrial, demonstrando i pelo aumento no consumo de O2 em mitocôndrias em estado 4. Em decorrência destas lesões observamos também o intenso inchamento mitocondrial, indicado por experimentos de espalhamento de luz e microscopia eletrônica de transmissão. O inchamento não foi bloqueado por ciclosporina A, um inibidor do poro de transição mitocondrial. DDE também induziu a perda do potencial de membrana da organela, demonstrado pelo monitoramento do indicador fluorescente safranina O e aumento da peroxidação lipídica atestado pela quantificação de malondialdeido (MDA). Estes resultados indicam que DDE promove alterações estruturais no citocromo e podendo levar ao comprometimento da atividade da proteína, além de promover alterações em parâmetros mitocondriais, indicando um possível envolvimento na disfunção mitocondrial promovida por estresse oxidativo. / Lipid hydroperoxide-derived α,β-unsaturated aldehydes are involved in several cellular processes such as gene expression, aging, Alzheimer disease and mitochondrial dysfunction. In this work we have investigated adduct formation in lysine, histidine and cytochrome c by trans,trans-2,4-decadienal (DDE), an endogenously lipoperoxidation product. DDE is also a widespread environment aldehyde found, for example, in food and as a contaminant in water. Alterations in rat liver mitochondrial parameters such as oxygen consumption, membrane potentials, swelling and lipoperoxidation were also investigated. LC-ESI/MS experiments indicated that DDE react with aminoacids lysine and histidine producing adducts. In addition, MALDI-TOF experiments indicated increases in the molecular weight of cytochrome c consistent with the formation of DDE adducts via the Schiff base mechanism. Our data shows that the protein modification was time, pH and DDE-concentration dependent, leading to the formation of at least six adducts after 2 h incubation at pH 7.4. ESI-Q-TOF MS analysis of tryptic digests indicated that H-33, K-39, K-72 and K-100 were modified by DDE. These adducts are present in clusters of basic amino acid residues, which are believed to participate in the interaction of cytochrome c with mitochondrial membrane and cytochrome c oxidase. A blue shift in the Soret band from 409 to 406 nm was also observed, indicating heme crevice opening and displacement of heme sixth ligand (Met-80) coordination in modified protein. DDE (180 µM) treatment increases the rate of mitochondrial oxygen consumption, suggesting a partial mitochondrial uncoupling. Moreover, extensive mitochondrial swelling upon treatment with DDE (900 nM-162 &#181M) was observed by light scattering and transmission electron microscopy experiments. These effects were not prevented by the mitochondrial permeability transition inhibitor cyclosporin A. A DDE concentration-dependent loss in the inner mitocondrial membrane potential, monitored by safranin O fluorescence and an increase in lipoperoxidation were also observed. All together, these results suggest that reactive aldehydes can induce inner mitochondrial membrane damage playing a role in mitochondrial dysfunction associated with oxidative stress.
76

Diagnostic de défauts des systèmes contrôlés via un réseau / Fault diagnosis of networked control systems

Chabir, Karim 09 July 2011 (has links)
Aujourd'hui, les réseaux de communications sont largement utilisés pour relier les points de ressources, qui permettent la transmission de données à distance, de réduire la complexité dans le cadre de câblage et les coûts de support et de fournir l'aide dans la maintenance. En raison de ces avantages, les réseaux ont été introduits dans les systèmes automatiques au cours de ces dernières décennies et de nouveaux protocoles de réseau industriel ont été également développés pour assurer le contrôle à distance. Les systèmes contrôlés en réseau SCR (Networked Control System NCS) sont des systèmes automatiques traditionnels où les actionneurs, les capteurs, les contrôleurs et des autres composants sont distribués autour d'un réseau de communication, qui peut être partagé ou non avec d'autres applications. Les données de commande et de diagnostic sont échangées entre les composants du système (capteur, contrôleur, actionneur) via ce réseau partagé. Cette nouvelle architecture de système de contrôle introduit des problèmes originaux, en termes de retard variable affectant la transmission, des pertes de paquets, etc. Dans l'objectif de maintenir de bonnes performances du module de diagnostic face à des éventuelles variations introduites par le réseau, il est intéressant d'introduire des nouvelles approches. Nous avons rapporté les résultats relatifs aux techniques d'estimation optimale à base de filtre de Kalman, de façon à constituer un document aussi complet que possible traitant la génération de résidus et l'isolation des défauts dans SCR. Notre contribution consiste, dans un premier temps, à développer un modèle d'état d'un système contrôlé via un réseau. En deuxième temps, nous proposons un générateur de résidus en se basant sur les hypothèses simulant le retard induit par le réseau. Finalement, nous développons un filtre isolateur pour identifier directement les défauts affectant les actionneurs dans un SCR / Today's communications networks are widely used to connect the resources, enabling the remote data transmission, reducing the cabling complexity, minimizing costs and providing easy maintenance. Because of these advantages, the networks have been introduced in automatic systems during recent decades and new industrial network protocols were also developed for the remote control. The systems controlled by networks, the term "Networked Control Systems (NCS)" are automatic traditional systems where the actuators, the sensors, the controllers and other components are distributed around a communication network that can be shared or not with other applications. The data of both control and diagnostic are exchanged between system components (sensor, controller and actuator) via the shared network. This new architecture of control system introduces new problems in terms of variable delay affecting the transmission, the packet loss, etc. With the aim to maintain good performance of diagnostic module face of possible changes introduced by the network, it is interesting to introduce new approaches. We have reported results for the optimal estimation techniques based on Kalman filter, thus creating a report as complete as possible, treating the residual generation and fault isolation in NCS. Our contribution consists, firstly, to develop a state space model of a system controlled via a network. Secondly, we propose a residual generator based on the delay models induced by the network. Finally, we develop a isolation filter in order to directly identify in the actuators faults in a SCR
77

The Role of Tumor and Tumor Microenvironment on Breast Cancer-Associated Adipocyte Plasticity

Pearce, Janina V 01 January 2019 (has links)
Cancer-associated cachexia is a condition defined by a sustained net-negative energy imbalance. Although the different types of adipose tissue – white, beige, and brown – have been implicated in contributing to cancer-associated cachexia, the mechanisms of these maladaptive changes and their impact on whole-body energy expenditure have not been fully elucidated. Using breast cancer as our model, we demonstrate white adipose tissue browning in murine and human breast cancer; furthermore, we demonstrate that this effect is extremely localized and takes place early in tumor progression. We utilized in vitro cell culture techniques and demonstrate that cancer secreted factors and cross-talk with white adipocytes decrease expression of classic white adipose tissue-related genes. We also demonstrate in murine and human culture models that cancer secreted factors reduce white adipocyte lipid droplet size, and cross-talk between cancer cells and adipocytes results in an increase in lipolysis-related gene expression. Interestingly, our results strongly suggest that in mice, neither cancer secreted factors nor cross talk with adipocytes can induce white adipose tissue browning, indicate that this process likely occurs independently of direct cancer interactions with local white adipocytes. We demonstrate that interleukin 6, a cytokine with previous implications in white adipose tissue browning, induces interleukin 6-mediated signaling; however, that signaling alone is not enough to directly induce white adipose tissue browning. We present preliminary data suggesting that immune cell population shifts within the white adipose tissue of mice with breast cancer tumors may be source of white adipose tissue browning. We show that the Virginia Commonwealth University Health System has an identifiable population of patients with cancer with what we hypothesize as maladaptive thermogenic adipose tissue activity, and discuss ongoing experiments aimed at understanding the implications of these changes on whole body energy expenditure in human patients. Lastly, in a case of autoimmune diabetes mellitus in the setting of an extra-adrenal paraganglioma, we demonstrate that the interaction between cancer and whole-body metabolism is multifaceted. Together, these experiments demonstrate that adipose tissue plasticity occurs in breast cancer (and other cancers), and that different drivers for individual changes exist within the tumor microenvironment. We predict that further exploration of the exact mechanisms and translational implications will provide useful information to lead to new therapeutic treatments for patients with cancer-associated cachexia.
78

Experimental studies of proton translocation reactions in biological systems : Electrogenic events in heme-copper oxidases

Lepp, Håkan January 2008 (has links)
<p>Terminal heme-copper oxidases (HCuOs) are transmembrane proteins that catalyze the final step in the respiratory chain - the reduction of O<sub>2</sub> to H<sub>2</sub>O, coupled to energy conservation by generation of an electrochemical proton gradient. The most extensively investigated of the HCuOs are the <i>aa</i><sub>3</sub>-type oxidases, to which cytochrome <i>c</i> oxidase (Cyt<i>c</i>O) belongs, which uses energy released in the O<sub>2</sub>-reduction for proton pumping. The bacterial nitric oxide reductases (NORs) have been identified as divergent members of the HCuO-superfamily and are involved in the denitrification pathway where they catalyze the reduction of NO to NO<sub>2</sub>. Although as exergonic as O<sub>2</sub>-reduction, this reaction is completely non-electrogenic. Among the traditional HCuOs, the <i>cbb</i><sub>3</sub>-type oxidases are the closest relatives to the NORs and as such provide a link between the <i>aa</i><sub>3</sub> oxidases and the NORs. The <i>cbb</i><sub>3</sub> oxidases have been shown to pump protons with nearly the same efficiency as the <i>aa</i><sub>3</sub> oxidases, despite low sequence similarity.</p><p>This thesis is focused on measurements of membrane potential generating reactions during catalysis in the Cyt<i>c</i>O and the <i>cbb</i><sub>3</sub> oxidase from <i>Rhodobacter sphaeroides</i>, and the NOR from <i>Paracoccus</i> <i>denitrificans</i>, using a time resolved electrometric technique. The pH dependence of the membrane potential generation in Cyt<i>c</i>O showed that only one proton is taken up and that no protons are pumped, at high pH. An additional kinetic phase was also detected at high pH that presumably originates to from charge-transfer within the K-pathway. Possible reasons for uncoupling, and the extent of charge-transfer, were studied using structural variants of Cyt<i>c</i>O. The measurements established that electrons and protons are taken up from the same side of the membrane in NOR. In addition, the directionality for proton uptake in <i>cbb</i><sub>3</sub> oxidase appeared to be dependent on the choice of substrate while proton pumping was indicated to occur only during O<sub>2</sub>-reduction.</p>
79

Experimental studies of proton translocation reactions in biological systems : Electrogenic events in heme-copper oxidases

Lepp, Håkan January 2008 (has links)
Terminal heme-copper oxidases (HCuOs) are transmembrane proteins that catalyze the final step in the respiratory chain - the reduction of O2 to H2O, coupled to energy conservation by generation of an electrochemical proton gradient. The most extensively investigated of the HCuOs are the aa3-type oxidases, to which cytochrome c oxidase (CytcO) belongs, which uses energy released in the O2-reduction for proton pumping. The bacterial nitric oxide reductases (NORs) have been identified as divergent members of the HCuO-superfamily and are involved in the denitrification pathway where they catalyze the reduction of NO to NO2. Although as exergonic as O2-reduction, this reaction is completely non-electrogenic. Among the traditional HCuOs, the cbb3-type oxidases are the closest relatives to the NORs and as such provide a link between the aa3 oxidases and the NORs. The cbb3 oxidases have been shown to pump protons with nearly the same efficiency as the aa3 oxidases, despite low sequence similarity. This thesis is focused on measurements of membrane potential generating reactions during catalysis in the CytcO and the cbb3 oxidase from Rhodobacter sphaeroides, and the NOR from Paracoccus denitrificans, using a time resolved electrometric technique. The pH dependence of the membrane potential generation in CytcO showed that only one proton is taken up and that no protons are pumped, at high pH. An additional kinetic phase was also detected at high pH that presumably originates to from charge-transfer within the K-pathway. Possible reasons for uncoupling, and the extent of charge-transfer, were studied using structural variants of CytcO. The measurements established that electrons and protons are taken up from the same side of the membrane in NOR. In addition, the directionality for proton uptake in cbb3 oxidase appeared to be dependent on the choice of substrate while proton pumping was indicated to occur only during O2-reduction.
80

CaracterizaÃÃo bioquÃmica e molecular da oxidase terminal da plastoquinona (PTOX) em Zea mays / Molecular and biochemical characterization of plastoquinone terminal oxidase (PTOX) in Zea mays

Francisco Yuri Maia de Sousa 28 October 2008 (has links)
Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / O cloroplasto à uma organela caracterÃstica dos organismos fotossintetizantes sendo seu papel primordial na geraÃÃo de energia a partir de gÃs carbÃnico e Ãgua. Essa organela pode ter seu funcionamento comprometido quando submetida a estresses ambientais devido a fragilidade e complexidade do sistema. Para evitar perdas provocadas pelo estresse existem vÃrios mecanismos de adaptaÃÃo e regulaÃÃo das reaÃÃes que ocorrem no cloroplasto. Recentemente caracterizou-se mais um desses provÃveis mecanismos que foi chamado de clororespiraÃÃo. A clororespiraÃÃo foi esclarecida com a descoberta de uma enzima similar a oxidase alternativa da mitocondria que chamou-se de oxidase terminal do plastÃdeo (PTOX). A funÃÃo dessa respiraÃÃo do cloroplasto permanece incerta, mas uma das hipÃteses mais aceitas à que o funcionamento da clororespiraÃÃo poderia prevenir a formaÃÃo de espÃcies reativas de oxigÃnio atravÃs da reciclagem dos intermediÃrios redutores do cloroplasto. No presente trabalho foi caracterizado a presenÃa de dois genes que codificam para a oxidase terminal do plastÃdeo em plantas de Zea mays. Estudou-se tambÃm a expressÃo diferencial de ambos genes da PTOX em resposta ou estresse hÃdrico, alÃm da caracterizaÃÃo da clororespiraÃÃo atravÃs da atividade da NADH desidrogenase plastidial (NDH) em gel de poliacrilamida. A caracterizaÃÃo molecular dos genes da PTOX mostrou homologia de 60% quando comparadas as sequÃncias dos genes e de 79% quando comparadas as prÃ-proteÃnas traduzidas. Os genes dessa proteÃna tÃm estruturas similares, sendo compostos por oito introns e 9 Ãxons. Um estudo das regiÃes dos promotores dos genes mostrou que existiam elementos comuns porÃm a presenÃa de elementos diferentes como, o elementos cis MBS que à responssivo à seca, poderia revelar uma regulaÃÃo diferencial dos genes. A resposta diferencial foi confirmada atravÃs de RT-PCR semiquantitativo. O gene chamado de ptox1 teve sua expressÃo estÃvel, podendo ser considerado um gene constitutivo, enquanto que o gene chamado de ptox2 teve um aumento da expressÃo proporcional ao estresse aplicado tanto em folhas como em raÃzes de plantas de milho. A anÃlise da atividade da NDH em gel (zimograma) revelou a presenÃa dessa enzima em cloroplastos de milho confirmando a presenÃa das enzimas da clororespiraÃÃo. O estudo filogenÃtico de sequencias de cDNA de bancos de dados mostraram que milho e sorgo pertencentes ao grupo das monocotiledÃneas, sÃo espÃcies muito prÃximas e que compartilham dois genes ortÃlogos da PTOX identificados como ptox1 e ptox2. Concluiu-se pela primeira vez a presenÃa de dois genes da PTOX no genoma do milho, uma monocotiledÃena de metabolismo C4. Os genes foram denominados de ptox1 e ptox2. Eles foram encontrados em raÃzes e folhas e apenas o gene da ptox2 pareceu ser induzido em resposta ao estresse osmÃtico. / The chloroplast is an organelle characteristic of photosynthetic organisms and their role in generating energy from carbon dioxide and water. This organelle may be functionally compromised when subjected to environmental stress due to the fragility and complexity of the system. To avoid losses caused by stresses plants have evolved various coping mechanisms, as well as, regulation of the reactions that occur in the chloroplast. Most recently it was characterized one of these mechanisms that was called chlororespiration. The chlororespiration was bring to light with the discovery of an enzyme, similar to the alternative oxidase of mitochondria, that was called the plastid terminal oxidase (PTOX). The function of this chloroplast respiration remains uncertain, but one of the most accepted hypothesis is that the operation of chlororespiration could prevent the formation of reactive oxygen species by recycling the reducing intermediates of the chloroplast. The present study characterized the presence of two genes encoding the plastid terminal oxidase in plants of Zea mays., and its differential expression in response to water stress. It was also characterized the chlororespiration through the activity of plastidial NADH dehydrogenase (NDH) in polyacrylamide gel. The molecular characterization of PTOX genes showed 60% homology when compared sequences of genes, but 79% when compared to pretranslated proteins. The genes of this protein have similar structures, being composed of nine exons and eight introns. A study of regions of the promoters of the genes showed that there were common elements, but the presence of different elements such as the cis elements that MBS responsive to drought, could reveal a differential regulation of genes. The differential response was confirmed by semiquantitative RT-PCR. The gene called ptox1 had its expression level stable and could be considered a constitutive gene, while the gene called ptox2 had an increased expression proportional to the applied stress in both leaves and roots of maize plants. The analysis of NDH activity gel (zimograms) revealed the presence of this enzyme in maize chloroplasts suggesting the existence of the chlororespiratory pathway. The phylogenetic analysis of cDNA sequences from NCBI databases showed that maize and sorghum, being closely related species, share two genes )identified as orthologs of PTOX (ptox1 and ptox2). It was confirmed for the first time the presence of two PTOX genes in the genome of maize, a C4-metabolism monocotyledon and its differential expression under drought stress.

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