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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.
31

Estudos da eletro-oxidação de etanol em nanocatalisadores de PdNi e PdCu / Study of ethanol electro-oxidation on PdNi and PdCu nanocatalysts

Milian, Rosendo Parra [UNESP] 07 March 2017 (has links)
Submitted by ROSENDO PARRA MILIAN null (rparram71289@gmail.com) on 2017-03-29T21:23:46Z No. of bitstreams: 1 Dissertação_Mestrado Quimica ROSENDO2017.pdf: 7139645 bytes, checksum: 4a067eda23c61d350682552eab51a0e4 (MD5) / Approved for entry into archive by Luiz Galeffi (luizgaleffi@gmail.com) on 2017-03-30T18:26:38Z (GMT) No. of bitstreams: 1 milian_rp_me_araiq.pdf: 7139645 bytes, checksum: 4a067eda23c61d350682552eab51a0e4 (MD5) / Made available in DSpace on 2017-03-30T18:26:38Z (GMT). No. of bitstreams: 1 milian_rp_me_araiq.pdf: 7139645 bytes, checksum: 4a067eda23c61d350682552eab51a0e4 (MD5) Previous issue date: 2017-03-07 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Esse trabalho consistiu em sintetizar, caracterizar e avaliar o desempenho catalítico para a oxidação de etanol de catalisadores contendo nanopartículas de PdCu e PdNi com diferente conteúdo do segundo metal (Cu e Ni em 10, 20, 30, 40 e 50%). A síntese foi realizada pelo método do poliol modificado e as nanopartículas foram suportadas em carbono de alta área superficial. Os catalisadores de PdCu e PdNi sintetizados foram caracterizados por difração de raios-X (DRX), microscopia eletrônica de transmissão em modo varredura (STEM), espectroscopia fotoeletrônica de raios-X (XPS) e espectroscopia de absorção de raios-X (XAS). A caracterização eletroquímica foi feita por voltametria cíclica em meio ácido e alcalino. A atividade catalítica foi avaliada por cronoamperometria em solução alcalina contendo etanol. De forma geral, os dados mostraram a incorporação do segundo metal (Cu e Ni) na estrutura cristalina do Pd que resulta na contração da rede cristalina, nanopartículas pequenas (menores que 5 nm) e presença de aglomerados. Tanto para PdCu quanto para PdNi, a formação de liga com o segundo metal produz um aumento da ocupação eletrônica da banda 4d do Pd. A presença de espécies oxidadas tem efeito oposto, ou seja, produz uma diminuição do preenchimento da banda. No caso de PdCu, os dados de XPS indicaram uma diminuição da quantidade de Pd metálico na superfície. O efeito contrário foi observado para PdNi. As atividades catalíticas para a oxidação de etanol foram menores que para Pd, diferentemente do que mostram a maioria dos dados da literatura. Resultados de espectroscopia de absorção-reflexão no infravermelho por transformada de Fourier (FTIRAS) mostraram que em todos os casos o principal produto da oxidação de etanol é acetato. PdCu/C (70:30) e PdNi/C (90:10) foram os catalisadores que apresentaram maior atividade catalítica para a oxidação de etanol em meio alcalino no seus respetivos conjuntos. / This work consisted in the synthesis, characterization and evaluation of the catalytic performance for the oxidation of ethanol of catalysts containing PdCu and PdNi nanoparticles with different contents of the second metal (Cu and Ni at 10, 20, 30, 40 and 50%). The synthesis was carried out by a modified polyol method and the nanoparticles were supported on high surface area carbon. Catalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy scanning mode (STEM), X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS). The electrochemical characterization was done by cyclic voltammetry in acid and alkaline medium. The catalytic activity was evaluated by chronoamperometry in alkaline solution containing ethanol. In general, data showed incorporation of the second metal (Cu and Ni) into the crystal structure of Pd that results in the contraction of the Crystal lattice, small particles (smaller than 5 nm) and the presence of agglomerates. For PdCu as well as for PdNi, the formation of alloy with the second metal produces an increase in the electronic occupancy of the Pd 4d band. The presence of oxidized species has the opposite effect, i.e., produces a decrease in the band filling. For PdCu, XPS data indicated a decrease in the percentage of metallic Pd on the surface. The opposite was observed for PdNi. The catalytic activities for the oxidation of ethanol were lower than for Pd, differently from what most data in the literature show. Results of measurements by Fourier transformed absorption-reflection infrared spectroscopy showed that the main product of the oxidation of ethanol is, in all cases, acetate. The PdCu/C (70:30) and PdNi/C (90:10) exhibited the highest catalytic activity for ethanol oxidation in alkaline solution of the corresponding set of catalysts.
32

Implication of immune system in chondrosarcoma progression and therapeutic response : Could immunotherapy play a role in chondrosarcoma treatment ? / L’implication du système immunitaire dans la progression et la réponse thérapeutique du chondrosarcome : Est-ce que l’immunothérapie peut jouer un rôle dans le traitement du chondrosarcome ?

Simard, François 14 June 2016 (has links)
Le chondrosarcome (CHS) est caractérisé par une grande chimio et radiorésistance ; il y a un besoin urgent de nouvelles stratégies thérapeutiques pour cette tumeur. Parmi celles-ci, certaines approches d'immunothérapie pourraient être d'un grand intérêt. Nous étudions actuellement l'implication du système immunitaire dans la progression du CHS et la réponse thérapeutique à la fois sur des échantillons humains et dans le modèle de chondrosarcome de rat (SRC).Dans le CHS humain et de rat, des infiltrats immunitaires composés de lymphocytes et macrophages ont été identifiés dans la zone péritumorale. L’infiltration immunitaire est en corrélation avec l’évolution de la tumeur (grade, envahissement et taille). L'expression de PD1 et PDL1 ont été détectée dans les infiltrats immunitaires et cellules tumorales du CHS chez l’homme et le rat. Le niveau d'expression PD-L1 en corrélation avec la survie des patients et le taux de rechute. Dans le model SRC, la déplétion sélective de lymphocytes T a entrainé une accélération de la progression tumorale, tandis que la déplétion de macrophages l’a ralenti. Les splénocytes isolés de rats porteurs de CHS ont montré une cytotoxicité spécifique dirigée contre les cellules de chondrosarcome (27%), qui a diminué de manière significative avec des rats appauvrie en CD3 (11%). La voie de signalisation PI3K/mTOR ne peut pas être associée à une immunothérapie car elle induit une action immunosuppressive in vivo.L'environnement immunitaire contribue à la progression du CHS à la fois chez l’homme et chez le rat, ce qui suggère que une approche immunomodulatrice avec des anticorps bloquant PDL1 pourrait être testée pour le CHS / Chondrosarcoma is highly resistant to chemotherapy and radiation and there is an urgent need in developing new therapeutic strategies for this malignancy; among these, some immunotherapy approaches could be of great interest. We are currently investigating the immune system implication in chondrosarcoma progression and therapeutic response both on human samples and in rat chondrosarcoma model (SRC). In human and rat chondrosarcoma, immune infiltrates composed of lymphocytes and macrophages were identified in the peritumoral area. Immune infiltrates composition was found correlated with tumors characteristics and evolution (grade, invasiveness and size). Expression of PD-1 and PD-L1 was detected in CHS immune infiltrates, both in human and rat (and on tumor cells). PD-L1 expression level correlated with patients survival and relapse rate. In SRC, T lymphocytes depletion resulted in an accelerated tumor progression, while CD163+ macrophages depletion slowed down tumor progression. Splenocytes isolated from CHS bearing SRC showed a specific cytotoxicity directed against chondrosarcoma cells (27%), which significantly decreased in CD3 depleted SRC (11%). The immune environment contributes to CHS progression in both human and animal models, this associated with expression of immune checkpoint PD1/PDL1 suggest that immunomodulatory approaches with PD-L1 blocking antibody could be applied in CHS; this approach is currently being tested in SRC
33

Statistisk analys av partiella urladdningar / Statistical analysis of partial discharges

Backström, Kristoffer January 2010 (has links)
<p>This thesis concerns partial discharges in stator windings and the possibility of analyzing data using statistical methods. Partial discharges, or PD, are a physical phenomenon in which discharges occur locally due to large electric fields. PD can occur in or adjacent to the insulation of stator windings and causes breakdown of the insulating materials. PD measurement can provide an idea of how widespread the PD activity is. A technique to measure and analyze PD that has become very popular over the last few decades is phase resolved PD patterns. These patterns supplies a "fingerprint" of the PD activity and by visually interpreting this patterns one can, in addition to read the intensity of the PD, also get a picture of what type of PD that is active. The problem with phase resolved PD patterns is that they are very complex and difficult to interpret. By applying statistical methods to PD patterns it has been investigated in this thesis whether the interpretation of the PD patterns can be simplified. The results show that the proposed methods have some advantages as they can quantify trends in the patterns. The methods have also shown to have severe limitations due to the fundamental properties of the PD patterns.</p> / <p>Detta examensarbete berör partiella urladdningar i statorlindningar och möjligheten att analysera mätdata med hjälp av statistiska metoder. Partiella urladdningar, eller PD, är ett fysikaliskt fenomen som innebär att urladdningar sker lokalt på grund av stora elektriska fältstyrkor. PD kan ske i eller intill isoleringen i statorlindningar och medför att isoleringsmaterialen bryts ner. Genom att mäta aktiviteten av PD kan man få en uppfattningav hur utbredd förekomsten av PD är. En teknik för att mäta och analysera PD som blivit mycket populär senaste decennierna är fasupplösta PD-mönster. Med dessa fås ett ”fingeravtryck” av PD-aktiviteten och genom att visuellt tolka det mönster som åskådliggörs kan man förutom intensitet av PD även få en god bild av vilken typ av PD somär aktiv. Problemet med fasupplösta PD-mönster är att de är mycket komplexa och svårtolkade. Genom att applicera statistiska metoder på fasupplösta PD-mönster har det i detta examensarbete undersökts om tolkningen kan förenklas. Resultaten visar på att de föreslagna metoderna har vissa fördelar då de kan kvantifiera tendenser som finns i mönstren. Metoderna har även stora begränsningar då egenskaperna i fasupplösta PDmönster ofta beror på många andra faktorer än bara de partiella urladdningarna i sig.</p>
34

MCNP modeling of prostate brachytherapy and organ dosimetry

Usgaonker, Susrut Rajanikant 30 September 2004 (has links)
Using the computer code Monte Carlo N-Particle (MCNP), doses were calculated for organs of interest such as the large intestine, urinary bladder, testes, and kidneys while patients were undergoing prostate brachytherapy. This research is important because the doses delivered to the prostate are extremely high and the organs near the prostate are potentially at risk for receiving high doses of radiation, leading to increased probabilities of adverse health effects such as cancer. In this research, two MCNP version 4C codes were used to calculate the imparted energies to the organs of interest delivered by 125I and 103Pd. As expected, the organs nearest to the prostate received the highest energy depositions and the organs farthest from the prostate received the lowest energy depositions. Once the energy depositions were calculated, the doses to the organs were calculated using the known volumes and densities of the organs. Finally, the doses to the organs over an infinite time period were calculated.
35

Statistisk analys av partiella urladdningar / Statistical analysis of partial discharges

Backström, Kristoffer January 2010 (has links)
This thesis concerns partial discharges in stator windings and the possibility of analyzing data using statistical methods. Partial discharges, or PD, are a physical phenomenon in which discharges occur locally due to large electric fields. PD can occur in or adjacent to the insulation of stator windings and causes breakdown of the insulating materials. PD measurement can provide an idea of how widespread the PD activity is. A technique to measure and analyze PD that has become very popular over the last few decades is phase resolved PD patterns. These patterns supplies a "fingerprint" of the PD activity and by visually interpreting this patterns one can, in addition to read the intensity of the PD, also get a picture of what type of PD that is active. The problem with phase resolved PD patterns is that they are very complex and difficult to interpret. By applying statistical methods to PD patterns it has been investigated in this thesis whether the interpretation of the PD patterns can be simplified. The results show that the proposed methods have some advantages as they can quantify trends in the patterns. The methods have also shown to have severe limitations due to the fundamental properties of the PD patterns. / Detta examensarbete berör partiella urladdningar i statorlindningar och möjligheten att analysera mätdata med hjälp av statistiska metoder. Partiella urladdningar, eller PD, är ett fysikaliskt fenomen som innebär att urladdningar sker lokalt på grund av stora elektriska fältstyrkor. PD kan ske i eller intill isoleringen i statorlindningar och medför att isoleringsmaterialen bryts ner. Genom att mäta aktiviteten av PD kan man få en uppfattningav hur utbredd förekomsten av PD är. En teknik för att mäta och analysera PD som blivit mycket populär senaste decennierna är fasupplösta PD-mönster. Med dessa fås ett ”fingeravtryck” av PD-aktiviteten och genom att visuellt tolka det mönster som åskådliggörs kan man förutom intensitet av PD även få en god bild av vilken typ av PD somär aktiv. Problemet med fasupplösta PD-mönster är att de är mycket komplexa och svårtolkade. Genom att applicera statistiska metoder på fasupplösta PD-mönster har det i detta examensarbete undersökts om tolkningen kan förenklas. Resultaten visar på att de föreslagna metoderna har vissa fördelar då de kan kvantifiera tendenser som finns i mönstren. Metoderna har även stora begränsningar då egenskaperna i fasupplösta PDmönster ofta beror på många andra faktorer än bara de partiella urladdningarna i sig.
36

Development of an Underwater Vehicle Simulation Platform

Du, Jiun-Hua 15 November 2011 (has links)
In the development of underwater vehicles, it is necessary to conduct performance test in the water tank. However, different factors need to be considered depending on different cases. The purpose of this paper is to construct a simulation platform in the air to study the scenarios like side current or constant height profiling. Although these tests are difficult to be performed in the water tank, we can get some solutions from observing the dynamics of simulation platform. The simulation platform we used consists of three links to constraint the motion in a polar coordinate system. It carries a wireless micro-camera, and two DC motor-driven propellers. At the end of the distal link and metal disk is attached on the other side of the pivot of the last link to provide counter-weight which can simulate different status of the "buoyancy" of the platform. The encoder which is uses to trace the motion of the simulation platform, is mounted at each join between two links. The control program has two parts: servo control of propellers and target tracking. In order to approach to the real-time searching, we derived image with gray scale instead of color form to increase image refreshing rate during the tracking process. For the current experiment, the target is at dot generated by an LED. The location of the bright dot is detected by a histogram-based threshold, and the actual location is further refined with intensity-weighted algorithm. The offset between of the target and the center of the image is used as the feedback to command the propellers to drive the platform. The goal is to keep the target at the center of the image as close as possible. A linear PD control (proportional - derivative) is implemented to drive the propellers. Preliminary experiments show that the simulation platform can track a target with about 15 frames per second refreshing rate under the condition that the target does not move too fast and vanishes in the image. When ROV with laser scanner syetem, seafloor away from ROV's accuracy is necessary. In this eassay, we use tracking angle and tracking bright dot to qualify and quantify the influence of buoyancy and propeller on the altitude control in different cases.
37

none

Lin, Chi-sung 06 July 2005 (has links)
none
38

none

Shin, Trey 10 February 2006 (has links)
none
39

Role of angiotensinergic neurotransmission at nucleus reticularis ventrolateralis during experimental endotoxemia

Ou, Ching-Ju 26 June 2001 (has links)
In this study, we investigated the role of angiotensinergic neurotransmission at nucleus reticularis ventrolateralis (NRVL), and the subtype of angiotensin receptors involved, during experimental endotoxemia induced by E. coli lipopolysaccharide (LPS). In adult male Sprague-Dawley rats maintained under propofol anesthesia (30 mg/kg/h), paralyzed with pancuronium (2 mg/kg/h) and mechanically ventilated (85-95 stroke/min, 2.5-3 ml/stroke), intravenous administration of LPS (15 or 30 mg/kg) induced an immediate hypotension, followed by a rebound increase and a secondary decrease in systemic arterial pressure (SAP). LPS also reduced the power density of the very low-frequency (0-0.25 Hz) and low-frequency (0.25-0.8 Hz) components of SAP signals (Phase ¢¹), which represented the sympathetic vasomotor tone, followed by an increase (Phase ¢º) and a secondary decrease (Phase ¢»). Pretreatment with microinjection of the selective non-peptide AT1 receptor antagonist, losartan (1.6 nmol), or the selective non-peptide AT2 receptor antagonist, PD-123319 (1.6 nmol), into the bilateral NRVL significantly reduced the survival time after the induction of acute experimental endotoxemia. Both pretreatments shortened the duration of Phase ¢º and Phase ¢» in acute endotoxemia, accelerated the secondary hypotension, and excited the power density of the very low-frequency. We conclude that endogenous angiotensin ¢º at the NRVL may play a crucial role in the maintenance of SAP during acute experimental endotoxemia, possibly via an action on both AT1 and AT2 subtype receptors on the very low-frequency component of SAP spectrum.
40

MCNP modeling of prostate brachytherapy and organ dosimetry

Usgaonker, Susrut Rajanikant 30 September 2004 (has links)
Using the computer code Monte Carlo N-Particle (MCNP), doses were calculated for organs of interest such as the large intestine, urinary bladder, testes, and kidneys while patients were undergoing prostate brachytherapy. This research is important because the doses delivered to the prostate are extremely high and the organs near the prostate are potentially at risk for receiving high doses of radiation, leading to increased probabilities of adverse health effects such as cancer. In this research, two MCNP version 4C codes were used to calculate the imparted energies to the organs of interest delivered by 125I and 103Pd. As expected, the organs nearest to the prostate received the highest energy depositions and the organs farthest from the prostate received the lowest energy depositions. Once the energy depositions were calculated, the doses to the organs were calculated using the known volumes and densities of the organs. Finally, the doses to the organs over an infinite time period were calculated.

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