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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.
61

A potencialidade do agente protetor do grupo amino na síntese de quitosana quimicamente modificada para o uso em sorção, liberação de fármaco e calorimetria / The potentialy of protective agent in the amino group to synthesize chemically modified chitosan for use in sorption, drug release and calorimetry

Oliveira, Cintia dos Santos, 1985- 10 September 2014 (has links)
Orientador: Claudio Airoldi / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Química / Made available in DSpace on 2018-08-26T11:26:42Z (GMT). No. of bitstreams: 1 Oliveira_CintiadosSantos_D.pdf: 3684874 bytes, checksum: 818c9e07a2f155ac52889f6ddcf9deab (MD5) Previous issue date: 2014 / Resumo: O biopolímero quitosana foi quimicamente modificado com aminas após a prévia proteção do grupo amino com benzaldeído. A reação de proteção forneceu o biopolímero BZL, que foi ativado com epicloridrina (EAC). A presença do grupo epóxido, proveniente da interação com a epicloridrina permitiu a inclusão de 2-aminometilpiridina, 2-aminopiridina, 4-aminopiridina, tetraetilenopentamina, 1,3-(aminopropilimidazol), 1-(2-aminoetil)piperazina e 1,4-bis(3-aminopropil) piperazina. Após a remoção do benzaldeído foram obtidos os biopolímeros CTN, C2MF, C4MF, TETF, IZLF, 2PPF e 3PPF, respectivamente, os quais foram caracterizados por análise elementar, difração de raios X, ressonância magnética nuclear do núcleo de carbono no estado sólido e espectroscopia na região do infravermelho. As caracterizações comprovaram o sucesso da reação de proteção dos grupos amino, bem como da remoção do benzaldeído. Os biopolímeros foram aplicados na remoção dos cátions metálicos cobre e cádmio, bem como na remoção dos corantes azul reativo 15 (RB-15), verde brilhante (BG), amarelo reativo (RY) e azul reativo (RB). Os experimentos foram realizados pelo método de batelada e os resultados obtidos foram ajustados à regressão não linear dos modelos de Langmuir, Freundlich e Sips, obtendo-se melhores ajustes ao último modelo. Os biopolímeros demonstraram uma melhor afinidade pelo cobre e dentre os corantes utilizados, uma melhor afinidade por RY. Os biopolímeros C2MF, C4MF, CTN, IZLF e TETF também foram carregados com os fármacos ibuprofenato de sódio (IBU) e diclofenaco de sódio (DCLO). Os estudos de liberação foram realizados em fluidos corpóreos simulados, obtendo-se perfis de liberação mais lentos para o DCLO. Através da calorimetria isotérmica foi investigado o processo de interação IBU ou Cu2+ com os biopolímeros. Os resultados indicaram processos endotérmicos, espontâneos e entropicamente favoráveis para o fármaco e exotérmicos, espontâneos e entalpicamente favoráveis para o cátion / Abstract: The chitosan biopolymer was chemically modified with amines after prior protection of the amino groups with benzaldehyde. The protection reaction provided the BZL biopolymer, which was activated with epichlorohydrin (EAC). The presence of epoxide groups derived from the epichlorohydrin allowed the inclusion of 2-aminomethylpyridine, 2-aminopyridine, 4-aminopyridine, tetraethylenepentamine, 1,3-(aminopropylimidazole), 1-(2-aminoethyl) piperazine and 1,4-bis(3-aminopropyl) piperazine. After bezaldehyde removal CTN, C2MF, C4MF, TETF, IZLF, 2PPF and 3PPF biopolymers were obtained, respectively, which were characterized by elemental analysis, X-ray diffraction, nuclear magnetic resonance of carbon nucleus in the solid state and infrared spectroscopy. The characterizations confirmed the success of protective reaction of amino groups as well as the benzaldehyde removal. The biopolymers were applied for the removal of copper and cadmium and also for reactive blue 15 (RB-15), brilliant green (BG), reactive yellow (RY) and reactive blue (RB) dyes. The experiments were carried out by batch method and the results were fitted with non-linear regression of the models of Langmuir, Freundlich and Sips, where the better fit was obtained using the last model. The biopolymers demonstrated better affinity for copper and among the dyes used, the best affinity was observed for RY. The C2MF, C4MF, CTN, TETF and IZLF biopolymers were also loaded with sodium ibuprofen (IBU) and diclofenac (DCLO) drugs. The release investigations were performed in simulated body fluids, resulting in slower release profile for DCLO. Through isothermal calorimetry processes, the interaction of IBU or Cu2+ with biopolymers was studied. The results indicated endothermic, spontaneous and entropically favorable processes for the drug and exothermic, spontaneous and favorable enthalpy process for the cation / Doutorado / Quimica Inorganica / Doutora em Ciências
62

Development of chemical labeling methods for organelle molecule analysis / オルガネラ分子の化学的修飾法の開発

Fujisawa, Alma 23 July 2019 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第22015号 / 工博第4627号 / 新制||工||1721(附属図書館) / 京都大学大学院工学研究科合成・生物化学専攻 / (主査)教授 浜地 格, 教授 梅田 眞郷, 教授 跡見 晴幸 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM
63

Synthèse et caractérisation de dérivés amphiphiles du xanthane : application à la stabilisation d'émulsions / Synthesis and characterization of amphiphilic xanthan derivatives : application as emulsions stabilizers

Fantou, Céline 14 December 2018 (has links)
Les polysaccharides amphiphiles sont constitués d’un squelette hydrophile sur lequel sont greffés des groupements hydrophobes. Ils possèdent des propriétés rhéologiques accrues dues à leur capacité d’auto-organisation en solution aqueuse mais également interfaciales dues à leurs propriétés d’adsorption aux interfaces eau/huile. Néanmoins, peu d’études s’intéressent à conférer ce type de propriétés à des polysaccharides complexes en termes de structure ou de conformation, comme le xanthane. En effet, ce polymère adopte en solution deux conformations distinctes selon les conditions expérimentales : une forme ordonnée hélicoïdale rigide et une forme désordonnée de type pelote flexible.Partant de ce constat, l’objectif de ce travail de thèse est de déterminer l’impact de la rigidité du squelette du xanthane modifié hydrophobiquement sur les propriétés amphiphiles en solution mais également sur les propriétés stabilisantes en émulsion.Il s’avère que la conformation adoptée par le polymère pendant le processus de greffage a un impact majeur sur ses propriétés rhéologiques : le xanthane modifié sous forme désordonnée possède un caractère associatif, contrairement au xanthane modifié sous forme ordonnée.De plus, le xanthane modifié hydrophobiquement est capable, sous certaines conditions, de former et de stabiliser des émulsions H/E, sans ajout de tensioactif moléculaire, en se partitionnant entre stabilisation de l’interface eau/huile et maintien de la viscosité de la phase aqueuse continue. / Amphiphilic polysaccharides are composed of a hydrophilic backbone grafted with hydrophobic moieties. They show specific rheological properties due to their capacity to self-associate in solution, but also interfacial properties due to their ability to adsorb at the water/oil interface. However, only few studies describe the chemical modification of complex heteropolysaccharides regarding their structure or their conformation, such as xanthan. Indeed, this polysaccharide can adopt in solution two distinct conformations depending on experimental conditions: an ordered rigid helix or a disordered flexible coil.The objective of this work is to determine the impact of the chain stiffness of hydrophobically modified xanthan on associative properties in solution, but also on stabilizing properties in emulsion.The conformation adopted by the polymer during the grafting procedure has a major impact on the rheological properties: xanthan modified under disordered conformation is an associative polysaccharide, contrary to xanthan modified under its ordered conformation.In addition, hydrophobically modified xanthan is able, under certain conditions, to form and stabilize O/W emulsion, without further addition of molecular surfactant, by partitioning between stabilization of the water/oil interface and viscosifying the continuous aqueous phase.
64

Site-specific chemical modification of mitochondrial respiratory complex I / ミトコンドリア呼吸鎖複合体Iの位置特異的化学修飾に関する研究

Masuya, Takahiro 23 March 2017 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第20418号 / 農博第2203号 / 新制||農||1047(附属図書館) / 学位論文||H29||N5039(農学部図書室) / 京都大学大学院農学研究科応用生命科学専攻 / (主査)教授 三芳 秀人, 教授 宮川 恒, 教授 森 直樹 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DGAM
65

Molecular mechanisms underlying treatment of acute type 1 diabetes with an anti-TLR4/MD2 antibody

Locker, Kathryn CS January 2020 (has links)
No description available.
66

Surfactant-Aided Matrix Assisted Laser Desorption/Ionization Mass Spectrometry (SA-MALDI MS)

Tummala, Manorama January 2004 (has links)
No description available.
67

Modification Reactivity Analysis of Human Replication Protein A in Biologically Important States

Yoakum, Ryan James 17 May 2016 (has links)
No description available.
68

Mucin preparation and assembly into new biomaterials

Zhong, Xueying January 2016 (has links)
Mucins, the main macromolecular constituent responsible for gel-forming property in mucus, have great potential to act as new biological hydrogel for medical applications. Click chemistry reaction is an attractive tool to be applied in both bioconjugation and material science to form covalent bonds between molecules. Herein the click chemistry reaction of tetrazine-norbornene ligation was adapted to form click mucin hydrogel using purified commercial available bovine submaxillary mucin (BSM). This study included the characterization, purification and chemical modification of commercial available BSM. The flow filtration purification was chosen after investigating the effectiveness and yields of four different purification strategies. The reactivity of tetrazine and norbornene-functionalized BSM was evident from the formation of robust mucin hydrogel within minutes after mixing the two components. / Mucin, den viktigaste makromolekylära beståndsdel som ansvarar för den gelbildande egenskapen i slem, har stor potential att fungera som en ny biologisk hydrogel för medicinska tillämpningar. Klick-kemi reaktioner är attraktiva verktyg som kan användas i både biokonjugering och materialvetenskap för att bilda kovalenta bindningar mellan molekyler. I detta projekt användes renat kommersiellt köpt bovint submaxillärt mucin (BSM) i en klick-kemi reaktion för att sammanlänka tetrazin och norbornylen. Denna reaktion anpassades för att bilda en mucin hydrogel. Detta projekt inkluderade karakterisering, rening och kemisk modifiering av kommersiellt köpt BSM. Flödesfiltrering valdes som reningsmetod efter undersöking av effektivitet och utbyte av fyra olika reningsstrategier. Reaktiviteten hos tetrazin och norbornen-funktionaliserad BSM var uppenbar från bildandet av robust mucin hydrogel inom några minuter efter de två komponenterna sammanblandats.
69

Role of methionine sulfoxide reductase in thermal-induced spreading depression coma in Drosophila melanogaster

Unknown Date (has links)
Drosophila melanogaster encounter periods of increased temperature or decreased oxygen in its native environment. One consequence of these environmental stresses is increased production of reactive oxygen species that damage major molecules within cells. Another consequence is that flies fall into a protective coma where biological functions are minimized to conserve energy expenditures. This biological phenomenon is called spreading depression. The overarching aim of this project is to determine if methionine sulfoxide reductases affect entrance or exit from the protective coma induced by acute thermal stress. The data revealed that complete deficiency of Msr in young flies causes a faster induction of the coma. In both young and old flies, Msr does not affect average recovery time but does affect the pattern of recovery from coma. Entrance into the coma is age dependent with young flies maintaining activity longer than before entering into the coma as compared to old flies. / by Karin Schey. / Thesis (M.S.)--Florida Atlantic University, 2012. / Includes bibliography. / Mode of access: World Wide Web. / System requirements: Adobe Reader.
70

Studies on the mechanism by which sulindac sensitizes cancer cells to oxidative stress

Unknown Date (has links)
by Alexander Kreymerman. / Thesis (M.S.)--Florida Atlantic University, 2011. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2011. Mode of access: World Wide Web. / Sulindac is a known NSAID that has also been shown to have anti-cancer activity that is not related to its ability to inhibit COX 1 and 2. During the past 15 years there have been a large number of studies attempting to elucidate its mechanism of action. Our laboratory has shown that sulindac can both protect normal cells and enhance the killing of cancer cells under oxidative stress from H2O2 and TBHP. However, except for mitochondrial dysfunction and ROS production, the mechanism by which sulindac sensitized the cancer cells to oxidative stress remains unknown. Results of this research project suggest that the effect of sulindac and oxidative stress not only involves mitochondrial ROS production, but also aspects of the preconditioning response. In normal cells this leads to survival by a preconditioning pathway, likely involving PKCε. . However, cancer cells react by initiating a pathway leading to apoptosis involving PKCδ.

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