• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 12
  • 3
  • 1
  • 1
  • Tagged with
  • 17
  • 17
  • 9
  • 6
  • 5
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 2
  • 2
  • 2
  • 2
  • 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.
11

Design, synthesis, and characterization of bivalent glutathione S-transferase inhibitors using combinatorial chemistry /

Mahajan, Sumit S., January 2006 (has links)
Thesis (Ph. D.)--University of Washington, 2006. / Vita. Includes bibliographical references (leaves 121-140).
12

Evaluating the inter and intra batch variability of protein aggregation behaviour using Taylor dispersion analysis and dynamic light scattering

Hulse, W.L., Gray, J., Forbes, Robert T. January 2013 (has links)
No / Biosimilar pharmaceuticals are complex biological molecules that have similar physicochemical properties to the originator therapeutic protein. They are produced by complex multi-stage processes and are not truly equivalent. Therefore, for a biosimilar to be approved for market it is important to demonstrate that the biological product is highly similar to a reference product. This includes its primary and higher order structures and its aggregation behaviour. Representative lots of both the proposed biosimilar and the reference product are analysed to understand the lot-to-lot variability of both drug substances in the manufacturing processes. Whilst it is not easy to characterise every variation of a protein structure at present additional analytical technologies need to be utilised to ensure the safety and efficacy of any potential biosimilar product. We have explored the use of Taylor dispersion analysis (TDA) to analyse such batch to batch variations in the model protein, bovine serum albumin (BSA) and compared the results to that obtained by conventional dynamic light scattering analysis (DLS). Inter and intra batch differences were evident in all grades of BSA analysed. However, the reproducibility of the TDA measurements, enabled the stability and reversibility of BSA aggregates to be more readily monitored. This demonstrates that Taylor dispersion analysis is a very sensitive technique to study higher order protein states and aggregation. The results, here, also indicate a correlation between protein purity and the physical behaviour of the samples after heat shocking. Here, the protein with the highest quoted purity resulted in a reduced increase in the measured hydrodynamic radius after heat stressing, indicating that less unfolding/aggregation had occurred. Whilst DLS was also able to observe the presence of aggregates, its bias towards larger aggregates indicated a much larger increase in hydrodynamic radii and is less sensitive to small changes in hydrodynamic radii. TDA was also able to identify low levels of larger aggregates that were not observed by DLS. Therefore, given the potential for immunogenicity effects that may result from such aggregates it is suggested that TDA may be suitable in the evaluating detailed batch to batch variability and process induced physical changes of biopharmaceuticals and biosimilars.
13

Avaliação do praguicida aldicarbe e seus produtos de transformação em matriz ambiental -- desenvolvimento e comparação de técnicas analíticas / Evaluation of aldicarb pesticide and its transformation products in environmental matrix - development and comparison of analytical techniques

Souza, Erica Rodrigues de 02 April 2009 (has links)
Os praguicidas carbamatos surgiram na década de 70. Este grupo de substâncias possui atividade anticolinesterásica, com variado grau de toxicidade. São solúveis em água e termicamente instáveis. O praguicida aldicarbe faz parte do grupo dos carbamatos, sendo um metil carbamato de oxima. Contaminações de águas subterrâneas e superficiais pelo aldicarbe já foram demonstradas, devido a alta solubilidade deste composto em água e sua alta capacidade de lixiviação em solo. Este trabalho visa o desenvolvimento de métodos analíticos para separação e quantificação de aldicarbe, aldicarbe sulfóxido e aldicarbe sulfona, por cromatografia líquida de alta eficiência, cromatografia líquida acoplada à espectrometria de massas e eletroforese capilar. O trabalho objetiva ainda avaliar a toxicidade aguda das três substâncias utilizando a bactéria marinha luminescente Vibrio fischeri. Amostras de água ultrapura, superficial e subterrânea foram submetidas a etapas de extração em diferentes cartuchos de fase sólida para avaliação da recuperação dos analitos e a realização da pré concentração dos mesmos. No método proposto por cromatografia líquida acoplada a espectrometria de massas, obteve-se limite de quantificação de 10 &#181;g.L-1, sendo que o alcançado no método proposto por cromatografia líquida com detecção por arranjo de diodos foi de 2 &#181;g.L-1. Já o método desenvolvido por eletroforese capilar com detecção por arranjo de diodos teve um limite de quantificação de 10 mg.L-1. Os resultados de CE50 obtida para o aldicarbe, aldicarbe sulfona e aldicarbe sulfóxido, no teste de toxicidade com a bactéria luminescente Vibrio fischeri foram respectivamente: 56,0 mg.L-1, 47,0 mg.L-1 e 7,8 mg.L-1. O método desenvolvido por cromatografia líquida se mostrou com sensibilidade satisfatória para análise de aldicarbe e seus produtos de transformação em água com níveis de quantificação dos compostos abaixo do limite determinado pela OMS (10 &#181;g.L-1. O método por eletroforese capilar não se mostrou com sensibilidade ideal para detecção dos analitos em níveis de traços. No teste de toxicidade aguda, observou-se que o aldicarbe sulfóxido é cerca de 7 vezes mais tóxico para a bactéria que o próprio aldicarbe, o que já é descrito na literatura para outras espécies. / Carbamates pesticides first appeared in the 1970s. This group of substances possesses anticholinesterasic activity, with varied toxicity degree. They are soluble in water and thermally unstable. The aldicarb pesticide belongs to the carbamates group, being an oxime methyl carbamate. Contaminations of underground and superficial waters by aldicarb have been demonstrated, due to the high solubility of this compound in water and its high capacity of lixiviation in soil. This dissertation aims to develop analytical methods for separation and quantification of aldicarb, aldicarb sulfoxide, and aldicarb sulfona, by high efficiency liquid chromatography, liquid chromatography-tandem mass spectrometry and capillary electrophoresis. The dissertation also focuses on evaluating the acute toxicity of the three substances using the luminescent marine bacterium Vibrio fischeri. Samples of ultrapure water, superficial and underground, were submitted to extraction stages in different cartridges of solid phase for evaluating the recovery of analytes and conducting their pre-concentration. In the method proposed by liquid chromatography-tandem mass spectrometry, a quantification limit of 10 &#181;g.L-1 was obtained, in comparison with the 2 &#181;g.L-1 achieved in the method proposed by liquid chromatography with diode-array detection. The method developed by capillary electrophoresis with diode-array detection had a quantification limit of 10 mg L-1. The results of CE50 obtained for the aldicarb, aldicarb sulfone and aldicarb sulfoxide, in the toxicity test with the luminescent bacterium Vibrio fischeri were respectively: 56.0 mg.L-1, 47.0 mg.L-1 e 7.8 mg.L-1 The method developed by liquid chromatography showed satisfactory sensitivity for analysis of aldicarb and its transformation products in water with quantification levels of the compounds below the limit determined by OMS (10 &#181;g.L-1</sup) . The method by capillary electrophoresis did not show ideal sensitivity for trace level detection of analytes. In the acute toxicity test, it was observed that the aldicarb sulfoxide is nearly 7 times more toxic for the bacterium than the aldicarb itself, which is already described in the literature for other species.
14

Avaliação do praguicida aldicarbe e seus produtos de transformação em matriz ambiental -- desenvolvimento e comparação de técnicas analíticas / Evaluation of aldicarb pesticide and its transformation products in environmental matrix - development and comparison of analytical techniques

Erica Rodrigues de Souza 02 April 2009 (has links)
Os praguicidas carbamatos surgiram na década de 70. Este grupo de substâncias possui atividade anticolinesterásica, com variado grau de toxicidade. São solúveis em água e termicamente instáveis. O praguicida aldicarbe faz parte do grupo dos carbamatos, sendo um metil carbamato de oxima. Contaminações de águas subterrâneas e superficiais pelo aldicarbe já foram demonstradas, devido a alta solubilidade deste composto em água e sua alta capacidade de lixiviação em solo. Este trabalho visa o desenvolvimento de métodos analíticos para separação e quantificação de aldicarbe, aldicarbe sulfóxido e aldicarbe sulfona, por cromatografia líquida de alta eficiência, cromatografia líquida acoplada à espectrometria de massas e eletroforese capilar. O trabalho objetiva ainda avaliar a toxicidade aguda das três substâncias utilizando a bactéria marinha luminescente Vibrio fischeri. Amostras de água ultrapura, superficial e subterrânea foram submetidas a etapas de extração em diferentes cartuchos de fase sólida para avaliação da recuperação dos analitos e a realização da pré concentração dos mesmos. No método proposto por cromatografia líquida acoplada a espectrometria de massas, obteve-se limite de quantificação de 10 &#181;g.L-1, sendo que o alcançado no método proposto por cromatografia líquida com detecção por arranjo de diodos foi de 2 &#181;g.L-1. Já o método desenvolvido por eletroforese capilar com detecção por arranjo de diodos teve um limite de quantificação de 10 mg.L-1. Os resultados de CE50 obtida para o aldicarbe, aldicarbe sulfona e aldicarbe sulfóxido, no teste de toxicidade com a bactéria luminescente Vibrio fischeri foram respectivamente: 56,0 mg.L-1, 47,0 mg.L-1 e 7,8 mg.L-1. O método desenvolvido por cromatografia líquida se mostrou com sensibilidade satisfatória para análise de aldicarbe e seus produtos de transformação em água com níveis de quantificação dos compostos abaixo do limite determinado pela OMS (10 &#181;g.L-1. O método por eletroforese capilar não se mostrou com sensibilidade ideal para detecção dos analitos em níveis de traços. No teste de toxicidade aguda, observou-se que o aldicarbe sulfóxido é cerca de 7 vezes mais tóxico para a bactéria que o próprio aldicarbe, o que já é descrito na literatura para outras espécies. / Carbamates pesticides first appeared in the 1970s. This group of substances possesses anticholinesterasic activity, with varied toxicity degree. They are soluble in water and thermally unstable. The aldicarb pesticide belongs to the carbamates group, being an oxime methyl carbamate. Contaminations of underground and superficial waters by aldicarb have been demonstrated, due to the high solubility of this compound in water and its high capacity of lixiviation in soil. This dissertation aims to develop analytical methods for separation and quantification of aldicarb, aldicarb sulfoxide, and aldicarb sulfona, by high efficiency liquid chromatography, liquid chromatography-tandem mass spectrometry and capillary electrophoresis. The dissertation also focuses on evaluating the acute toxicity of the three substances using the luminescent marine bacterium Vibrio fischeri. Samples of ultrapure water, superficial and underground, were submitted to extraction stages in different cartridges of solid phase for evaluating the recovery of analytes and conducting their pre-concentration. In the method proposed by liquid chromatography-tandem mass spectrometry, a quantification limit of 10 &#181;g.L-1 was obtained, in comparison with the 2 &#181;g.L-1 achieved in the method proposed by liquid chromatography with diode-array detection. The method developed by capillary electrophoresis with diode-array detection had a quantification limit of 10 mg L-1. The results of CE50 obtained for the aldicarb, aldicarb sulfone and aldicarb sulfoxide, in the toxicity test with the luminescent bacterium Vibrio fischeri were respectively: 56.0 mg.L-1, 47.0 mg.L-1 e 7.8 mg.L-1 The method developed by liquid chromatography showed satisfactory sensitivity for analysis of aldicarb and its transformation products in water with quantification levels of the compounds below the limit determined by OMS (10 &#181;g.L-1</sup) . The method by capillary electrophoresis did not show ideal sensitivity for trace level detection of analytes. In the acute toxicity test, it was observed that the aldicarb sulfoxide is nearly 7 times more toxic for the bacterium than the aldicarb itself, which is already described in the literature for other species.
15

Studies of protein structure, dynamics and protein-ligand interactions using NMR spectroscopy /

Tengel, Tobias, January 2007 (has links)
Diss. (sammanfattning) Umeå : Univ., 2008. / Härtill 4 uppsatser.
16

Estudo mecânico e microestrutural em dois sistemas de fixação interna usados em osteotomia sagital mandibular / Mechanical and microstructural evaluation of two internal fixation systems used in mandibular sagittal split ramus osteotomy

Mendes, Marcelo Breno Meneses, 1984- 24 August 2018 (has links)
Orientador: Roger William Fernandes Moreira / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-24T03:19:50Z (GMT). No. of bitstreams: 1 Mendes_MarceloBrenoMeneses_D.pdf: 3820602 bytes, checksum: 7c13797c10676481e3ebfd0492c570a9 (MD5) Previous issue date: 2014 / Resumo: O objetivo deste estudo foi avaliar, através da análise de rugosidade superficial, microscopia eletrônica de varredura (MEV), análise de composição através de espectroscopia de raios-X e análise de resistência mecânica, dois diferentes sistemas de fixação interna usados em fixação de osteotomia sagital do ramo mandibular. Foram selecionadas cinco placas retas do sistema 2,0 mm com quatro furos e 20 parafusos de 6 mm de comprimento de dois sistemas de fixação interna, grupo I: Tóride (Tóride Indústria e Comércio Ltda. -Mogi Mirim, São Paulo -Brasil) e grupo II: Medartis (Medartis AG -Basel, Suíça). Para os testes mecânicos, foram selecionadas dez hemimandíbulas de poliuretano, dividindo-as igualmente entre os grupos I e II. Inicialmente, foi realizada análise de rugosidade superficial em todas as placas dos dois sistemas, e os dados foram submetidos à análise de variância e teste de Tukey (p>0,05) para a comparação entre as médias. Em seguida, as mesmas placas foram avaliadas no espectrômetro por meio de difração de raios-X e logo após foram analisadas no MEV. Por último, foi realizado o teste mecânico, no qual as hemimandíbulas de poliuretano foram fixadas e submetidas ao teste de carregamento (1mm/min). Os dados foram analisados quanto à carga de pico (em Newtons) e o deslocamento de pico (em mm) para todos os grupos estudados, e posteriormente submetidos ao teste t. Os grupos testados apresentaram vestígios superficiais dos processos de usinagem, principalmente nas margens dos elos. O grupo II apresentou revestimento com uma camada de nitreto de titânio. A análise da rugosidade revelou diferença entre as regiões de centro e margem da placa para o grupo I; diferente do grupo II, o qual apresentou valor de rugosidade menor e mais uniforme. O teste mecânico revelou que o grupo II apresentou maior carga de pico. Os dados demonstraram que há diferença microestrutural e mecânica entre os grupos testados. / Abstract: The aim of this study was to evaluate, through surface roughness analysis, scanning electron microscopy (SEM), composition analysis by X-ray spectroscopy and analysis of mechanical strength, two different systems used in internal fixation of mandibular sagittal split osteotomy fixation. Five straight 2.0 mm system plates with four holes and 20 screws 6 mm length of two internal fixation systems were selected, group I: Toride (Toride Indústria e Comércio Ltda -Mogi Mirim, São Paulo -Brazil.) and group II: Medartis (Medartis AG -Basel, Switzerland). For mechanical testing, ten polyurethane hemimandibles were used, distributing them equally into groups I and II. Initially, surface roughness analysis was performed on all plates of the two systems, and the data were subjected to analysis of variance and Tukey's test (p> 0.05) for comparison between means. Then, the same plates were evaluated in the spectrometer by means of X-ray diffraction and after this evaluation, they were subjected to SEM. Finally, mechanical testing was performed, in which the polyurethane mandibles were fixed and subjected to the load (1mm/min) test on an Instron testing machine, Model 4411 (Instron Corp., Norwood, MA). Data were analyzed for peak load (in Newtons) and peak displacement (in mm) for all groups, and then subjected to t test. The groups tested showed superficial traces of machining processes, especially on links periphery. Group II had coated with a layer of titanium nitride. The roughness analysis revealed differences among the regions of the center and edge of the plate for group I; group II showed roughness value smaller and more uniform, than group I.The mechanical test showed that group II had higher peak load. The data demonstrated that there are microstructural and mechanical differences between the tested groups. / Doutorado / Cirurgia e Traumatologia Buco-Maxilo-Faciais / Doutor em Clínica Odontológica
17

Biološki potencijal i hemijska analiza vrsta roda Salix L. (Salicaceae) sa teritorije Republike Srbije / Biological potential and chemical analysis of species from the genus Salix L. (Salicaceae) from the territory of Republic of Serbia

Gligorić Emilia 18 January 2019 (has links)
<p>Rod Salix pripada porodici Salicaceae i obuhvata oko 450 vrsta &scaron;irom sveta, od kojih u Republici Srbiji raste oko 18. Kora vrbe ispoljava antiinflamatorno, antireumatsko, analgetičko i antipiretičko delovanje sinergističkim efektom njenih glavnih aktivnih supstanci &ndash; glikozida salicina, fenolnih i flavonoidnih jedinjenja. Ciljevi ovog rada bili su ispitivanje uticaja klasične i savremenih metoda ekstrakcije na hemijski sastav i biolo&scaron;ke aktivnosti ekstrakata različitih vrsta vrba, utvrđivanje razlika u sadržaju aktivnih komponenti i biolo&scaron;kom potencijalu između ekstrakata kore i ekstrakata lista iste vrste vrbe, kao i utvrđivanje razlika u sadržaju sekundarnih metabolita i antioksidantnoj aktivnosti kod ekstrakata različitih vrsta vrba. Ispitivanja su uključivala analizu 92 ekstrakta kore i lista osam predstavnika roda Salix, dobijenih različitim metodama (maceracija, ultrazvučna i mikrotalasna ekstrakcija) i pri različitim uslovima ekstrakcije (rastvarač, vreme, veličina čestica). Sadržaj ukupnih fenola i flavonoida, kao i antioksidativna aktivnost određeni su spektrofotometrijski. Hemijska karakterizacija ekstrakata vr&scaron;ena je primenom visokoefikasne tečne hromatografije (HPLC). Metodom in silico molekularnog dokinga ispitan je inhibitorni potencijal sastojaka ekstrakata prema enzimima ciklooksigenaze (COX-1 i COX-2) i acetilholinesterazi (AChE). Savremenim metodama ekstrakcije izolovan je veći broj pojedinačnih komponenata u najvećoj koncentraciji i dobijeni su ekstrakti sa jačim potencijalom neutralizacije hidroksilnih radikala. Klasična metoda maceracije 70% etanolom (v/v) bila je pogodnija za dobijanje ekstrakata sa jačim antioksidativnim potencijalom prema DPPH radikalu kod gotovo svih ispitivanih Salix vrsta. Kod većine Salix vrsta jači antioksidantni potencijal prema DPPH radikalu ispoljili su ekstrakti kore. Kod polovine ispitivanih vrsta ekstrakti lista su inhibisali hidroksilne radikale u većoj meri. Veći sadržaj pojedinačnih jedinjenja u ekstraktima kore ili lista zavisio je od same vrste vrbe. Najjaču antioksidantu aktivnost ispoljila je vrsta S. alba, dok je u pogledu hemijskog sastava najraznovrsnija vrsta bila S. fragilis. In silico analizom metodom molekularnog dokinga utvrđen je jak inhibitorni potencijal flavonoidnih jedinjenja kvercetina, naringenina i epikatehina, kao i hlorogenske kiseline među fenolnim kiselinama prema enzimima COX-1 i COX-2. Epikatehin, salicin i hlorogenska kiselina ispoljili su značajno inhibitorno delovanje na enzim AChE u doking studijama. Dobijeni rezultati ukazuju da pored kore i list vrbe ima veliki potencijal primene kao izvor značajnih fitokomponenata, kao i na mogućnost eksploatacije vrsta vrba koje nisu u komercijalnoj upotrebi kao lekovitih sirovina za izolovanje antioksidanasa i farmakolo&scaron;ki aktivnih supstanci.</p> / <p>The genus Salix belongs to the family Salicaceae and comprises about 450 species worldwide, out of which 18 grow in the Republic of Serbia. Willow bark exhibits anti-inflammatory, anti-rheumatic, analgesic and antipyretic effects through synergistic action of its main ingredients -glycosidesalicin, phenolic and flavonoid compounds. Aims of this paper were to analyse the impact of classical and modern extraction methods on chemical composition and biological activities of extracts of different willow species, determine the differences in the amount of active compounds and biological potential between bark and leaf extracts within the same willow species, as well as between extracts of various species. The analysis included 92 bark and leaf extracts of eight species from the genus Salix, obtained by different extraction methods (maceration, ulrasound and microwave assisted extraction) and conditions (solvent, time, particle size). Total phenolics and flavonoids content, as well as antioxidant activity were determined spectrophotometrically. Chemical characterization was carried out by high performance liquid chromatography (HPLC). Cyclooxygenase (COX-1 and COX-2) and acetylcholine esterase (AChE) inhibitory potential of compounds isolated from the extracts was examined by in silico method of molecular docking. Greater number of individual components in highest concentration, as well as exracts with stronger hydroxyl radical scavenging potential were obtained by modern extraction methods. Classical method of maceration with 70% ethanol (v/v) was more suitable for obtaining extracts with higher DPPH radical scavenging activity in the vast majority of tested species. In half of the analysed species leaf extracts inhibited hydroxyl radicals more than bark. Higher amount of individual compounds in bark or leaf extracts depended on the species itself. S. alba exhibited the strongest antioxidant activity, whereas S. fragilis had the most diverse chemical composition. Strong COX-1 and COX-2 inhibitory potential of flavonoids quercetin, naringenin and epicatechin, as well as chlorogenic acid among phenolic acids was determined by in silico molecular docking analysis. Molecular docking studies also demonstrated the inhibitory activity of epicatechin, salicin and chlorogenic acid toward AChE. The obtained results indicate that not only bark, but willow leaf as well could be used as source of significant phytochemicals and also the possibility of exploitation of willow species that are not commercially used as medicinal raw material for isolation of antioxidants and pharmacologycally active substances.</p>

Page generated in 0.0606 seconds