• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 74
  • 26
  • 8
  • 4
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 148
  • 142
  • 30
  • 21
  • 21
  • 15
  • 14
  • 13
  • 13
  • 11
  • 11
  • 9
  • 9
  • 9
  • 9
  • 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.
101

Altered distribution of inhibitory synaptic terminals in reeler cerebellum with special reference to malposition of GABAergic neurons / リーラーマウス小脳における抑制性神経回路の改変とGABA作動性ニューロンの位置異常との関係

高山, 千利 30 September 1994 (has links)
Hokkaido University (北海道大学) / 博士 / 医学
102

Surgery for aortic stenosis : with special reference to myocardial metabolism, postoperative heart failure and long-term outcome /

Vánky, Farkas, January 2006 (has links)
Diss. (sammanfattning) Linköping : Linköpings universitet, 2006. / Härtill 6 uppsatser.
103

Modeling and treatment of rat cervical spinal cord injury

Gensel, John Carib, January 2007 (has links)
Thesis (Ph. D.)--Ohio State University, 2007. / Title from first page of PDF file. Includes bibliographical references (p. 174-200).
104

Cristais de ácido glutâmico: crescimento, caracterização e cálculos ab initio / Crystals of glutamic acid: growth, characterization and calculations ab initio.

Pinheiro, José Auri January 2006 (has links)
PINHEIRO, José Auri. Cristais de ácido glutâmico: crescimento, caracterização e cálculos ab initio. 2006. 114 f. : Tese (Doutorado em Bioquímica) - Universidade Federal do Ceará, Centro de Ciências, Fortaleza-CE, 2006. / Submitted by Eric Santiago (erichhcl@gmail.com) on 2016-07-20T14:46:59Z No. of bitstreams: 1 2006_tese_japinheiro.pdf: 1742642 bytes, checksum: ea49b7e21bdd91f790bdc04ac6f5f777 (MD5) / Approved for entry into archive by José Jairo Viana de Sousa (jairo@ufc.br) on 2016-08-02T20:36:49Z (GMT) No. of bitstreams: 1 2006_tese_japinheiro.pdf: 1742642 bytes, checksum: ea49b7e21bdd91f790bdc04ac6f5f777 (MD5) / Made available in DSpace on 2016-08-02T20:36:49Z (GMT). No. of bitstreams: 1 2006_tese_japinheiro.pdf: 1742642 bytes, checksum: ea49b7e21bdd91f790bdc04ac6f5f777 (MD5) Previous issue date: 2006 / Done the work accomplish in this thesis it seeks the crystallization of the glutamic acid, favoring the obtaining of the phase α (metastable) in relation to the polymorph β. After the obtaining of the crystals they did take place the experimental measures of fluorescence, with views the comparison with the obtained theoretical data, considering the limitations of the method of simulation used ab-initio. Were the calculations of first principles accomplished to study the properties of the crystal of the glutamic acid in the modifications α and β in what she refers to the aspect structural, electronic (structure of bands) and optical (function of the dieletric complex), everything this in relation to the polymorphism conformational. The theory of the functional of the density (TFD) is it considered using a base of plane waves, pseudo potential ultrasoft, and the correlation-change potential inside of the Generalized-Gradient Approximation (GGA). Are the net parameters in agreement with the experimental results, although in the form α is it foreseen to have an indirect gap between the points of high symmetry and X, equal to 4.69 eV, for the form β a conclusion cannot be reached on the direct gap (-), due to imprecision of the calculation. The function dieletric of both polymorph are very similar in the case of a sample polycrystal, but it differs strongly in the case of the polarization of the light of the faces of the crystal 100 and 010 / O trabalho realizado nesta tese visa a cristalização do ácido glutâmico, favorecendo a obtenção da fase α (metaestável) em relação ao polimorfo β. Após a obtenção dos cristais realizaram-se as medidas experimentais de fluorescência, com vistas a comparação com os dados teóricos obtidos, considerando as limitações do método de simulação ab-initio utilizado. Os cálculos de primeiros princípios foram realizados para estudar as propriedades do cristal do ácido glutâmico nas modificações α e β no que se refere ao aspecto estrutural, eletrônico (estrutura de bandas) e óptico (função do complexo dielétrico), tudo isto em relação ao polimorfismo conformacional. A teoria do funcional da densidade (TFD) é considerada usando uma base de ondas planas, pseudopotenciais ultramacios, e o potencial de correlação-troca dentro do Generalized-Gradient Approximation (GGA). Os parâmetros de rede estão de acordo com os resultados experimentais, embora na forma α é previsto ter um gap indireto entre os pontos de alta simetria  e X, igual a 4.69 eV, para a forma β não pode-se tirar uma conclusão sobre o gap direto (-), devido a imprecisão do cálculo. A função dielétrica de ambos os polimorfos são muito semelhantes no caso de uma amostra policristalina, mas difere fortemente no caso da polarização da luz das faces do cristal 100 e 010.
105

Estudo da sinalização glutamatérgica, estresse oxidativo e morte celular em cérebros de ratos durante o envelhecimento

Ureshino, Rodrigo Portes [UNIFESP] 25 June 2008 (has links) (PDF)
Made available in DSpace on 2015-07-22T20:50:06Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-06-25. Added 1 bitstream(s) on 2015-08-11T03:25:52Z : No. of bitstreams: 1 Publico-10947.pdf: 1984469 bytes, checksum: 2cce63c3d607e63adb499e8742f10eed (MD5) / O envelhecimento é um processo multi-fatorial associado a déficits funcionais, sendo que o cérebro é um dos órgãos com maior susceptibilidade a doenças crônico-degenerativas. Dentre essas, as doenças de Alzheimer e de Parkinson apresentam maior prevalência na população global e levam à incapacitação severa do indivíduo. Assim, o entendimento dos mecanismos dessas doenças que estão relacionados com o envelhecimento é importante para a busca de alternativas de tratamento. Há evidências de que, em doenças neurodegenerativas, ocorrem alterações na homeostase do cálcio (Ca2+), o que pode contribuir para a morte celular por apoptose. No presente trabalho, buscamos investigar fenômenos envolvidos com a tríade Ca2+ -mitocondria- EROs (espécies reativas do oxigênio) (TOESCU, 2005) e a apoptose em corpo estriado de ratos no envelhecimento. Foram avaliadas a sinalização intracelular dinâmica (em tempo real) e estática (biologia molecular), a morfologia celular e ultraestrutural, a morfometria e bioenergética. Utilizando fatias cerebrais de ratos, observamos que os anmais senescentes apresentaram um aumento de Ca2+ citosólico maior que os animais jovens, após a estimulação glutamatérgica. Em seguida, utilizamos antagonistas parciais das duas classes de receptores, os metabotrópicos do grupo I e os ionotrópicos (NMDAR), para estudar os componentes desse aumento de Ca2+. Avaliamos também o aumento de Ca2+ citosólico mediado por agentes que mobilizam esse íon do retículo endoplasmático e da mitocôndria, mostrando que esses estoques de Ca2+ podem estar aumentados no envelhecimento. As medidas do ∆ψm basal mostraram que hei urna diminuição deste parâmetro no envelhecimento, sendo estas alterações condizentes com a inibição mais acentuada do complexo I da cadeia transportadora de elétrons e do aumento na produção de EROs. As alterações funcionais não implicaram em mudanças ultraestruturais da mitocôndria. Foram investigados a expressão gênica e o conteúdo proteíco de Bax e Bcl-2, mostrando um aumento da expressão de bax e uma redução de proteínas Bcl-2, o que pode ter uma relação com o aumento de apoptose encontrado no estriado dos animais senescentes. Desse modo, os resultados indicam que, no envelhecimento, existem alterações no controle intracelular de sinalização de Ca2+ e na bioenergética, que podem contribuir para o aumento de apoptose. / TEDE / BV UNIFESP: Teses e dissertações
106

Estudo do comportamento térmico de alguns aditivos alimentares por TG/DTG, DTA e DSC / Thermal behavior studies of some food additives by TG/STG, STA and DSC

Ronaldo Spezia Nunes 13 April 2009 (has links)
Estudos termoanalíticos de alguns aditivos alimentares da classe dos realçadores de sabor foram desenvolvidos visando avaliar sua estabilidade e resistência durante o preparo de alimentos a quente assim como investigar os eventuais intermediários de decomposição que poderiam resultar destes processos. Os sais foram obtidos de fontes industriais ou sintetizados e submetidos à caracterização por análise elementar, espectrometria vibracional na região do infra-vermelho, termogravimetria/termogravimetria derivada, análise térmica diferencial e em alguns casos, calorimetria exploratória diferencial. Foram estudados o ácido glutâmico e seus sais de amônio, lítio e sódio mono e dissubstituídos. Em todos os casos observou-se uma conversão a piroglutamato após desidratação dos sais monossubstituídos, a qual ocorre via a a-carboxila. A estabilidade térmica destes sais foi da ordem de 190-200 °C. No caso dos sais dissubstituídos de lítio e sódio não houve conversão ao piroglutamato pois as duas carboxilas estão salificadas. Os glutamatos de magnésio, cálcio estrôncio e bário, também foram preparados e investigados quanto ao seu comportamento térmico. Os sais se formaram na estequiometria 2:1 (ligante:metal), apresentando águas de hidratação em número característico e foram estáveis até 190- 200 °C. Finalmente foram estudados os mecanismos de decomposição térmica do inosinato-monofosfato de sódio e do guanilato-monofosfato de sódio, dois nucleotídeos que apresentam a propriedade de realçar o sabor de alimentos. Ambos apresentaram elevado grau de hidratação, para o qual foi possível distinguir mecanismos característicos de desidratação. A decomposição dos sais anidros ocorreu com saída do grupo purínico, seguida da decomposição do restante da molécula e formação de pirofosfato de sódio como resíduo final. / Thermal analytical studies of some food addictives of the flavor enhancer class were developed in order to evaluate their stability and resistance to the hot cooking process, as well as to identify the intermediaries of thermal decomposition that could remain at the end of such processes. The salts were obtained from industrial sources or synthesized and characterized by elemental analysis, infra-red spectroscopy, thermogravimetry/derivative thermogravimetry, differential thermal analysis and in some opportunities to differential scanning calorimetry. The glutamic acid and its ammonium, lithium and sodium salts mono and disubstituted were investigated. In all cases a conversion to pyroglutamate has been observed in the free acid and its monosubstituted salts after dehydration. The conversion undergoes by the ?-carboxyl group. The thermal stability was observed to be as high as 190-200 °C. In the case of the lithiu m and sodium dissubstituted salts any conversions to pyroglutamates were observed, once both carboxyl groups were salified. Magnesium, calcium, strontium and barium glutamates has also been synthesized and investigated in relation to its thermal behavior. The salts were formed in the 2:1 stoichiometry (ligand:metal), presenting hydration waters in a characteristic content and showed to be stable up to 190-200 °C. Finally the thermal decomposition mechanisms of dissodium inosinatemonophosphate and dissodium guanilate-monophosphate two nucleotides with flavor enhancement properties in food were also investigated. Both presented high degree of hydration, to which it was possible to propose a water release mechanism. The decomposition of the anhydrous salts occurred with release of the purine group followed by the decomposition of the rest of the molecule generating sodium pyrophosphate as residue.
107

Adsorção de aminoácidos em hidróxidos duplos lamelares: efeito da temperatura, pH e força iônica do meio / Adsorption of amino acids in layered double hydroxides: temperature, pH and ionic strength effects

Fabiano Silvério 28 January 2005 (has links)
Hidróxidos Duplos Lamelares (HDLs), são materiais lamelares constituídos de camadas positivamente carregadas de um hidróxido misto de dois metais (um di e um trivalente), com ânions hidratados no domínio interlamelar. Apesar de serem potenciais adsorventes, o estudo da adsorção de aminoácidos sobre estes sólidos ainda não foi realizado. Este é importante, pois abre caminho para a aplicação de HDLs na remoção e recuperação de aminoácidos de soluções aquosas, provenientes de processos industriais. Este trabalho teve por objetivo estudar a adsorção e a sorção dos aminoácidos: Ácido Aspártico (Asp), Ácido Glutâmico (Glu) e Fenilalanina (Phe), a partir de soluções aquosas, em HDLs do sistema [Mg-Al-CO3], verificando o efeito de variáveis como temperatura, pH e força iônica (FI) do meio. O adsorvente foi preparado pelo método de coprecipitação a pH variável e caracterizado quanto à composição, organização estrutural, textura e morfologia. A adsorção de Asp, Glu e Phe no HDL não calcinado indicaram que não ocorre a substituição do ânion interlamelar (CO32-), mas sim a adsorção por interação do aminoácido com as cargas residuais na superfície do HDL. O processo mostrou uma grande dependência das variáveis estudadas. A adsorção de Asp e Glu tem comportamento semelhante, embora o aumento da força iônica, seja mais pronunciado em pH 7 para o Asp, e em pH 10 para o Glu. Sem aumento da força iônica, as isotermas atingem ou se aproximam do patamar de adsorção destes aminoácidos, e o aumento na temperatura diminui a quantidade máxima adsorvida. A adsorção de Phe apresentou comportamento similar aos anteriores, exceto pelo fato do aumento da força iônica causar uma diminuição na adsorção. Os resultados obtidos para a sorção no HDL calcinado mostraram que inicialmente o HDL é reconstituído contendo ânions OH- intercalados que são deslocados pelo aminoácido conforme a concentração deste aumenta. Neste caso, Asp e Glu também apresentaram comportamentos semelhantes: as isotermas atingem um patamar onde a sorção torna-se constante e o aumento da temperatura diminui a quantidade sorvida. Para a Phe, a quantidade sorvida é muito maior que para os demais e não se observa o patamar de sorção constante. A temperatura não causa alteração significativa na quantidade sorvida. Os resultados de remoção dos aminoácidos, obtidos para o HDL calcinado se mostraram mais eficientes do que àqueles observados no HDL não calcinado. / Layered Double Hydroxides (LDHs), are lamellar materials constituted of positively charged layers of two cations mixed hydroxide (a bi and a trivalent one), with hydrated anions in the interlayer domain. In spite of they being potential adsorbents, the study of the adsorption of amino acids on these solids has not been done yet. This is important, because it opens the perspective for the application of LDHs to remove and to recover amino acids from aqueous solutions, resultant from industrial processes. The aim of this work was to study the adsorption and the sorption of the amino acids: Aspartic Acid (Asp), Glutamic Acid (Glu) and Phenylalanine (Phe), from aqueous solutions, in [Mg-Al-CO3] LDHs, verifying the effect of the variables: temperature, pH and ionic strength of the medium. The adsorbent was prepared by the coprecipitation method and characterized with respect to their composition, structural organization, texture and morphology. The adsorption of Asp, Glu and Phe in LDH indicated that the substitution of the interlayer anion (CO32-) doesn\'t occur, but the adsorption process occurs by the interaction of the amino acid with the residual charges on the LDH surface. The process showed a dependence on the parameters studied. The adsorption of Asp and Glu presented similar behavior, although the ionic strength effect is more pronounced in pH 7 for Asp, and in pH 10 for Glu. Without the increase in ionic strength, the isotherms reach or approach a plateau, and the increasing in the temperature reduces the maximum amount adsorbed. The adsorption of Phe has similar behavior to the previous ones, except at higher ionic strength, in which a decrease in the adsorption was observed. The results for the sorption in calcined LDH showed that the LDH are reconstituted with the OH- anions intercalated at low amino acid concentrations. The intercalation of amino acid becomes important as their concentration increase. In this case, Asp and Glu also presented similar behaviors: the isotherms reach a plateau where the sorption becomes constant and the increase of the temperature reduces the amount of sorbed amino acid. For Phe, the amount sorbed is higher than those for the others amino acids and the plateau of constant sorption was not observed. The temperature doesn\'t cause any significant alteration in the sorbed amount. The results of removing the amino acids on calcined LDH showed to be more efficient than those observed for the adsorption in LDH.
108

Root Yields, Sucrose, and Glutamic Acid Content of Sugar Beets as Influenced by Soil Moisture, Nitrogen Fertilization, Variety, and Harvest Date

Woolley, Donald G. 01 May 1956 (has links)
The United States produces about 1.8 million tons of sugar annually. Approximately 75 per cent of this production is derived from sugar beets. The importance of the sugar beet crop in national and world economy is justification for research effort as a means to more economical production. It is desirable that sugar beet processing be carried out in the most efficient manner. More effective utilization of the sugar beet and its by-products will add stability to the sugar beet industry. For the past 170 years, since Achard found that sugar could be used for human consumption and that pulp might be fed to cattle, sugar processors have made limited use of the non-sugar constituents of the sugar beet. These materials have been disposed of almost exclusively as livestock ration supplements. The non-sugar constituents have been largely responsible for failure to extract all of the sugar from the beet (13). As a result they have been viewed with suspicion by most sugar beet processors. However, recent development suggest that the utilization of sugar beet by-products will constitute a more important phase of the sugar beet industry in the future. At this critical period in the sugar beet industry, it is difficult to overemphasize the need for a better understanding of the chemical constituents of the sugar beet and the effects of various physiological factors upon them. One of the non-sugar constituents of the sugar beet which has recently received attention is glutamic acid. This has been brought about primarily by the discovery that the salt, monosodium glutamate, has an enhancing effect upon the flavor and palatability of many foods. Using the sugar beet as almost the exclusive source of glutamic acid, a new industry (utilizing over 100 tons of beet molasses daily) has developed to manufacture and market this food seasoner (28). Preliminary investigations at the Utah Experiment Station (14) showed that of all the chemical constituents determined, glutamic acid was the most variable. This agreed with earlier work in this field (16, 42). Being highly variable this constituent is a chief contributor to difficulties in sugar processing. The purpose of this study was to determine the effect of some of the major agronomic factors, such as moisture, fertility, variety, and sampling date, upon the glutamic acid content of the sugar beet.
109

Dubious Role Of Mycobacterium Paratuberculosis In Pathogenesis Of Type I Diabetes

Thanigachalam, Saisathya 01 January 2012 (has links)
Background: Type 1 Diabetes mellitus (TIDM) is a chronic disorder in which the insulin producing beta cells are selectively self-destroyed. Although the etiology of the disease has not been determined, genetic dispositions such as SLC11A1 polymorphism in suffering patients have been reported. The role of pathogenic microorganisms such as Mycobacterium avium subspecies paratuberculosis (MAP) in TIDM has also been recently debated. MAP is already known to cause paratuberculosis in cattle and now it is a strong suspect of causing autoimmune diseases in humans such as Crohn’s disease, multiple sclerosis, autoimmune Thyroiditis, rheumatoid arthritis and autoimmune diabetes. We hypothesis that molecular mimicry between MAP Heat shock protein 65K (Hsp65) and human Glutamic Acid Decarboxylase 65K (GAD65) can be the trigger which leads to the autoimmune destruction of beta cell in patients exposed to MAP . Method: To test the hypothesis, peptide sequences of MAP Hsp65 and human GAD65 were investigated using BLAST and PyMOL bioinformatics tools. Moreover, 18 blood samples from humans with TIDM and controls, and 100 sera samples from cattle with paratuberculosis and controls were evaluated for the presence of MAP, MAP DNA and its antibodies. Glucose, insulin and GAD65 antibodies were also determined in some of the clinical samples. Results: Peptide BLAST analysis revealed 44% identity between the two proteins with 75% positive identities in a 16 amino acid region. PyMOL structural analysis identified possible shared epitope regions of the proteins in its 3D conformation. Immunoblot analysis revealed a strong cross reactivity between lysate of E.coli recombinant of MAP Hsp65 and plasma from human subject with TIDM. A weak cross reactivity was also observed between healthy rat pancreatic homogenate and rabbit anti MAP IgG. Nested PCR using IS900-specific iv oligonucleotide primers did not detect MAP DNA in peripheral blood from 18 subjects with Type I Diabetes, Type II Diabetes and non-diabetic controls. Long term culture of leukocytes from blood samples from same subjects resulted in the presence of MAP in 3/10 (30%) TIDM and 4/8 (50%) control subjects. However anti MAP IgG were detected in 5/10 (50 %) TIDM samples compared to 3/8 (37.5 %) controls. Insulin level was measured in sera from paratuberculosis cattle and controls. In MAP infected cattle, insulin level ranged from below 0.1ng/ml to 2.456 ng/ml with an average of 0.36 +/- 0.57ng/ml compared to below 0.1ng/ml to 13.47ng/ml with an average of 2.86 +/- 3.00ng/ml in healthy cattle. Conclusion: Bioinformatics analysis between MAP Hsp65 and human GAD65 through BLAST and PyMOL analysis revealed a homology of 16 amino acid motif and possible shared epitope regions; immunohistochemistry analysis revealed a cross reactivity between rabbit antiMAP IgG and pancreatic cell homogenate from a healthy rat. Moreover, plasma from patient with TIDM (TD8), who was confirmed to be positive for MAP DNA and MAP IgG, reacted strongly with MAP Hsp65 in MAP protein lysate and MAP Hsp65 recombinant clone pmptb20. Culture of MAP from human leukocytes is significant despite the lack of correlation between MAP in samples from TIDM and controls. It is worth noting that some of the control subjects have not been evaluated for other autoimmune diseases possible MAP role. Additionally, antiMAP IgG levels in TIDM subjects compared to controls have raised a suspicion on the involvement of MAP in TIDM. The poor correlation of MAP in blood versus either the antiMAP IgG or the insulin level may be related with the fastidious nature of MAP and in vitro cultivation. Since MAP is the sole causative agent of Johne’s disease, it is significant that the insulin level is 8 folds less in MAP infected cattle compared to MAP free cattle. Overall, the data v is mixed and suggest that further study is needed to investigate the intriguing question to whether MAP is involved in TIDM or not.
110

Synthesis and Characterization of Novel Polyethers and Polypeptides for Use in Biomedicine and Magnetic Resonance Imaging

Liang, Jue 24 January 2014 (has links)
Copolymers that contain terminal or pendent functional groups have great potential in the biomedical area due to their biocompatibility and tunable properties.1-3 In this research, two vinyl functional epoxides, vinyldimethylsilylpropyl glycidyl ether (VSiGE) and ethoxy vinyl glycidyl ether (EVGE), were synthesized. These heterobifunctional monomers were polymerizable via the epoxide groups and can be functionalized via thiol-ene reactions through the pendent vinyl groups. A series of amphiphilic block copolyethers based on poly(ethylene oxide) and poly(1,2-butylene oxide) that incorporate VSiGE or EVGE were synthesized and characterized. The vinyl ether and vinyl silane functional groups were functionalized after polymerization and the functional polymers formed pH-sensitive micelles in aqueous medium. The copolyethers were loaded with ritonavir yielding well-controlled nanoparticles. Poly(L-glutamic acid) is comprised of naturally occurring L-glutamic acid repeating units that are linked together with amide bonds. In this research, we have prepared magnetic block ionomer complexes based on poly(ethylene oxide)-b-poly(L-glutamic acid) copolymers. This is of interest due to the biocompatibility and biodegradable nature of the poly(L-glutamic acid) component of the backbone. Allyl- and thiol-functional poly(ethylene oxide)-b-poly(L-glutamic acid) copolymers were also synthesized and coated onto the surface of iron oxide nanoparticles. Allyl- and thiol-tipped single particles were reacted with each other to prepare magnetic clusters. Transverse relaxivities of the clusters were found to be significantly higher than that of single particles. One major problem in commercial development of therapeutic proteins is their poor transport across cellular membranes and biological barriers such as the blood-brain barrier (BBB). One solution to this problem is to modify proteins with amphiphilic block copolymers such as PEO-b-PPO-b-PEO, Pluronics®. However, it isn't possible to independently tune the two PEO block lengths with commercial Pluronics® since a difunctional PPO macroinitator is utilized to grow both PEO blocks simultaneously (HO-EOn-b-POm-b-EOn-OH). Another challenge is introducing functional group which allows post-polymerization functionalization for specific applications. In this study, a series of heterobifunctional asymmetric amino-EOn1-b-POm-b-EOn2-OH block copolymers (APs) with different molecular weights of each block were synthesized and the amino terminal group was conjugated to an antioxidant enzyme, Cu/Zn superoxide dismutase (SOD1). The conjugates were characterized and their cellular uptake was investigated. / Ph. D.

Page generated in 0.0664 seconds