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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.
451

Desenvolvimento de formulações contendo voriconazol encapsulado em nanopartículas lipídicas e promotores químicos de absorção para aplicação tópica na unha / Development of formulations containing voriconazole encapsulated in lipid nanoparticles and chemical absorption promoters for topical nail application

Rocha, Kamilla Amaral David 18 August 2015 (has links)
Submitted by Liliane Ferreira (ljuvencia30@gmail.com) on 2018-02-28T14:49:21Z No. of bitstreams: 2 Dissertação - Kamilla Amaral David Rocha - 2015.pdf: 3193387 bytes, checksum: 6cc146ed197535b6a21627e8ffa4891c (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2018-02-28T16:16:32Z (GMT) No. of bitstreams: 2 Dissertação - Kamilla Amaral David Rocha - 2015.pdf: 3193387 bytes, checksum: 6cc146ed197535b6a21627e8ffa4891c (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-02-28T16:16:32Z (GMT). No. of bitstreams: 2 Dissertação - Kamilla Amaral David Rocha - 2015.pdf: 3193387 bytes, checksum: 6cc146ed197535b6a21627e8ffa4891c (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2015-08-18 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The voriconazole (VOR) is an antifungal from the thiazole class, which has a proven action against dermatophytes, main cause of onychomycosis. Topical treatment of pathologies located in the nail is highly desirable, since oral administration of antifungal agents have been shown ineffective. Thus, the goal is the work was the development of nanostructured lipid carriers (NLC) for nail topical administration of the VOR. To quantify VOR in the nail plate, an analytical method was developed and validated by high-performance liquid chromatography (HPLC) with detection in the UV-vis. CLNs were obtained with glyceryl behenate, Miglyol®, polysorbate 80, sorbitan trioleate surfactant, and a cationic cetilpiridíneo chloride (CPC) and different drug loading. Nanoparticles were characterized for medium size, PdI, zeta potential, encapsulation efficiency and recovery, morphology by scanning electron microscopy (SEM), and the stability. Hydration factor of the formulations and permeation enhancers was performed. Analysis of dry and hydrated hooves treated with NLC were achieved by SEM. Release and in vitro permeation studies were performed with unloaded drug (VOR-free) and VOR loaded NLC. The drug quantification method was linear in the concentration range from 0.4 to 40 mg / mL. The limit of quantitation was 400 ng/mL. Furthermore, the method was able to analyze the VOR without suffering interference from components of the nail and NLC. The NLC (n = 3) loaded with drug showed positive surface charge (around +25 mV) and average size of 230 nm. The NLC obtained had 1.75% of drug load, with encapsulation efficiency of 74.52 (+ 2.13)%. Hydration factor studies showed that the formulation with the highest amount of Miglyol was able to hydrate the nail more as well as the urea, which was the best promotor enhancer for nail hydration. NLC developed with and without addition of promoters were stable for a period of 150 days. In vitro release studies showed that the release VOR from the NLC occurs in a controlled manner from the lipid matrix. There was no significant difference in drug penetration when applied CLNs with and without promoter, for the VOR-Free. Although amounts of drug were found more deeply with the use of the CLN in the sample depletion assays, which can facilitate treatment of nail affected by onychomycosis. / O voriconazol (VOR) é um antifúngico da classe tiazol, que possui ação comprovada contra os dermatófitos, principais causadores da onicomicose. O tratamento tópico localizado de patologias na unha é altamente desejado, visto que a administração oral de antifúngicos têm se demonstrado ineficiente. Desta forma, o objetivo deste trabalho consiste no desenvolvimento de carreadores lipídicos nanoestruturados (CLN) para administração tópica do VOR na unha. Para a quantificação do VOR na placa ungueal foi desenvolvido e validado um método analítico por cromatografia líquida de alta eficiência (CLAE) com detecção no UV-vis. Os CLN foram obtidos com behenato de glicerila, Miglyol®, polissorbato 80, trioleato de sorbitano e tensoativo catiônico cloreto de cetilpiridnío (CPC), com diferentes cargas do fármaco. As nanopartículas foram caracterizadas quanto ao tamanho, PdI, potencial zeta, eficiência de encapsulação e recuperação, morfologia por microscopia eletrônica de varredura (MEV), e a estabilidade das mesmas. Avaliação do fator de hidratação das formulações e de promotores de permeação foi realizada. Análises dos cascos secos e hidratados com os CLN foram feitas por MEV. Estudos de liberação e permeação passiva in vitro do VOR livre e encapsulado em CLN foram realizados. O método de quantificação do fármaco mostrou-se linear na faixa de concentração de 0,4 a 40 μg/mL. O limite de quantificação foi de 400 ng/mL. Ainda, o método foi capaz de analisar o VOR sem sofrer interferência dos componentes da unha e dos CLN. Os CLN (n=3) carregados com fármaco apresentaram carga superficial positiva (em torno de +25 mV) e tamanho médio de 230 nm. Obtiveram-se carreadores com 1,75% de carga de fármaco e com eficiência de encapsulação de 74,52 (+ 2,13) %. A avaliação do fator de hidratação mostrou que a formulação com maior quantidade de Miglyol® foi capaz de hidratar mais a unha, assim como o promotor que apresentou melhor resultado foi a uréia (10%). Os CLN desenvolvidos com e sem adição de promotores se mostraram estáveis por um período de 150 dias. Os estudos de liberação in vitro demonstraram que a liberação do VOR a partir dos CLN ocorre de forma controlada a partir da matriz lipídica. Não houve diferença significativa na penetração do fármaco quando aplicado os CLN com e sem promotor, em relação ao VOR-Livre. Embora, quantidades de fármacos foram encontradas mais profundamente com uso dos CLN em ensaios de esgotamento da amostra, o que pode favorecer o tratamento de unhas acometidas pela onicomicose.
452

Buparvaquone nanostructured lipid carrier development: physicochemical and in vitro leishmanicidal performances / Desenvolvimento de carreadores lipídicos nanoestruturados contendo buparvaquona: caracterização físico-química e avaliação da atividade leishmanicida in vitro

Lis Marie Monteiro 05 October 2017 (has links)
Leishmaniases is a group of diseases caused by parasites of the genus Leishmania. The estimated number of deaths from visceral leishmaniases ranges from 20,000 to 50,000 annually. The most common treatment over the past 60 years has been pentavalent antimonials. Besides the doubtful effectiveness, they present several disadvantages such as the need for parenteral administration, large doses, long treatment, severe toxicity and parasite resistance. Buparvaquone (BPQ), a drug used for veterinary treatment of theileriosis, showed promising activity against Leishmania spp. However, due to its low aqueous solubility and bioavailability, it has failed in in vivo tests. The use of nanotechnologies has the potential to overcome these drawbacks due to the following advantages: increase in drug water-solubility, increase in therapeutic efficacy and treatment toxicity reduction. Therefore, the present work aimed the development, optimization, physical-chemical evaluation and in vitro performances of nanostructured lipid carriers (NLC) for BPQ encapsulation. The NLC preparation was performed by high pressure homogenization, and surface response and factorial design were applied to formulation optimization. In vitro dissolution profiles were evaluated in phosphate buffer pH 7.4 with tween 80 0.07% w/v or sodium dodecyl sulfate 1% w/v and simulated body fluid pH 7.4. Cytotoxicity was evaluated in mouse peritoneal macrophages and leishmanicidal activity in L. infantum amastigotes. Six optimized NCL were prepared and they showed solubility improvement from 1.5- fold to 611-fold when compared with free BPQ, depending on the formulation and medium. Dissolution profiles showed the NLC formulation suitability for BPQ regarding oral administration, the release could reach 83.29% of a 4mg dose in 30 minutes for formulation of 175.1 nm, while the free drug could be dissolved only 2.89% of the same dose after 4 hours. Moreover, formulation of 230.7 nm showed 81.42% of drug release in in phosphate buffer pH 7.4 with dodecyl sulfate 1.0% w/v after 30 minutes, while BPQ did not dissolved. Cytotoxicity assay showed the safety of all formulations. The iv CC50 values were close to 500 µM, while the IC50 against amastigotes was only 456.5 nM for free BPQ. Developed NLCs showed an increase in IC50 from 2.0 to 3.1-fold when compared to free drug in the in vitro leishmanicidal evaluation. Therefore, the NLC containing BPQ are a promising alternative for the treatment of leishmaniases as oral and parenteral drug dosage forms. Additionally, they have a potential use for lymphatic targeted drug delivery, which can be an innovative approach for this neglected disease. / Leishmanioses são um grupo de doenças causadas por parasitas do gênero Leishmania. O número estimado de óbitos por leishmaniose visceral varia entre 20.000 e 50.000 por ano. O tratamento mais comum nos últimos 60 anos tem sido os antimônios pentavalentes. Além da eficácia duvidosa, eles apresentam várias desvantagens, como a necessidade de administração parenteral, altas doses, tratamento prolongado, toxicidade severa e resistência parasitária. Buparvaquona (BPQ), um fármaco usado para tratamento veterinário da teileriose, mostrou atividade promissora contra Leishmania donovani. No entanto, devido à sua baixa solubilidade e biodisponibilidade aquosa, falhou em testes in vivo. O uso das nanotecnologias tem o potencial de superar esses obstáculos devido às seguintes vantagens: aumento da solubilidade em água, aumento da eficácia terapêutica e redução da toxicidade do tratamento. Portanto, o presente trabalho objetivou o desenvolvimento, otimização, avaliação físico-química e avaliação do desempenho in vitro de carreadores lipídicos nanoestruturados (NLC) para o encapsulação da BPQ. A preparação do NLC foi realizada por homogeneização de alta pressão e superfície de resposta e planejamento fatorial foram aplicados à otimização das formulações. Os perfis de dissolução in vitro foram avaliados em tampão fosfato pH 7.4 com tween 80 a 0.07% p/v ou dodecilsulfato de sódio 1.0% p/v e fluido corporal simulado pH 7.4. A citotoxicidade foi avaliada em macrófagos peritoneais de camundongos e atividade leishmanicida em amastigotas de L. infantum. Foram preparados quatro NCL otimizados e mostraram melhora da solubilidade de 1,5 a 611 vezes quando comparado com a BPQ livre, dependendo da formulação e do meio. Os perfis de dissolução mostraram a adequação da formulação NLC para BPQ em relação à administração oral. A dissolução pode atingir 83,29% de uma dose de 4.0 mg em 30 minutos para a formulação de 175,1 nm, enquanto o fármaco livre dissolveu apenas vi 2,89% da mesma dose após 4 horas. Além disso, a formulação de 230,7 nm mostrou 81,42% de liberação do fármaco em tampão fosfato pH 7.4 com dodecil sulfato de sódio 1.0% p/v após 30 minutos, enquanto o BPQ não se dissolveu. O teste de citotoxicidade mostrou a segurança de todas as formulações. Os valores CC50 foram próximos de 500 µM, enquanto o IC50 em amastigotas foi de apenas 456,5 nM para BPQ livre. Os NLC desenvolvidos mostraram um aumento no IC50 de 2,0 a 3,1 vezes quando comparado ao;fármaco livre na avaliação leishmanicida in vitro. Logo, as NLC contendo BPQ são uma alternativa promissora para o tratamento de leishmanioses como formas farmacêuticas oral e parenteral. Além disso, eles têm um uso potencial para a sítio-específico ao sistema linfático, o que pode ser uma abordagem inovadora para esta doença negligenciada.
453

Chemical looping combustion : a multi-scale analysis

Schnellmann, Matthias Anthony January 2018 (has links)
Chemical looping combustion (CLC) is a technique for separating pure carbon dioxide from the combustion of fuels. The oxygen to burn the fuel comes from the lattice oxygen contained in solid particles of an inorganic oxide (the 'oxygen carrier'), instead of from oxygen in the air. Thus only CO2 and water leave the combustor, or fuel reactor. Next, the water is condensed, leaving pure CO2. The oxygen carrier is regenerated by oxidising it in air in a second reactor, called the air reactor. Accordingly, a stream of pure carbon dioxide can be produced, uncontaminated with gases such as nitrogen, normally present when the fuel burns in air. This intrinsic separation with CLC enables CO2 to be separated more efficiently than with other techniques, such as post-combustion scrubbing of carbon dioxide from stack gases with amine-based solvents. The design of a CLC system and its performance within an electricity system represents a multi-scale problem, ranging from the behaviour of single particles of oxygen carrier within a reactor to how a CLC-based power plant would perform in an electricity grid. To date, these scales have been studied in isolation, with little regard for the vital interactions and dependences amongst them. This Dissertation addresses this problem by considering CLC holistically for the first time, using a multi-scale approach. A stochastic model was developed, combining the particle-and reactor-scales of CLC. It included an appropriate particle model and can be coupled to a detailed reactor model. The combination represented a significant change from existing approaches, uniquely accounting for all the important factors affecting the assemblage of particles performing in the CLC reactors. It was used to determine the regimes of operation in which CLC is sensitive to factors such as the manner in which the particles are reacting, the residence time distribution of particles in the two reactors, the particle size distribution and the reaction history of particles. To demonstrate that the approach could simulate specific configurations of CLC, as well as a general system, the model was compared with results from experiments in which CLC with methane was conducted in a laboratory-scale circulating fluidised bed. The long-term performance of oxygen carrier materials is important, because, in an industrial process, they would be expected to function satisfactorily for many thousands of hours of operation. Long-term experiments were conducted to evaluate the resistance of different oxygen carrier materials to physical and chemical attrition. The evolution of their chemical kinetics was also determined. The results were used to evaluate the impact of different oxygen carrier materials in a fuel reactor at industrial-scale. Finally, a theoretical approach was developed to simulate how a fleet of CLC-based power plants would perform within the UK's national grid. By understanding how different parameters such as capital cost, operating cost and measures of efficiency, compared with other methods of generation offering carbon reduction, desirable design modifications and needs for improvement for CLC were identified by utilising the theoretical and experimental work conducted at the particle- and reactor-scales.
454

A novel amplification gene SLC12A5 promotes cell proliferation and tumor metastasis in colorectal cancer / CUHK electronic theses & dissertations collection

January 2014 (has links)
Background & Aims: By whole genome sequencing, we identified for the first time that solute carrier family 12 member 5 (SLC12A5) gene located on chromosome 20q13.12 was amplified in colorectal cancer (CRC). We aimed to determine the amplification status of SLC12A5 and its clinical implication in CRC, and characterize the functional mechanisms of SLC12A5 in colorectal carcinogenesis. / Materials and Methods: Protein expression level of SLC12A5 was evaluated by immunohistochemistry. SLC12A5 amplification was verified by fluorescence in situ hybridization (FISH). The correlations between SLC12A5 expression and clinicopathologic parameters as well as the prognosis impact of SLC12A5 were analyzed in 195 CRC patients. The biological function of SLC12A5 in CRC cell lines were determined by cell viability, colony formation, invasion, migration, flow cytometry and in vivo tumorigenicity assays. Standard tail vein metastatic assay was performed to examine the effect of SLC12A5 in lung metastasis in nude mice. Western blot, luciferase reporter assays and human tumor metastasis PCR array were performed to evaluate SLC12A5 downstream effectors and related pathways. / Results: RT-PCR showed SLC12A5 was readily expressed in 7 of 9 CRC cell lines, but was absent in normal colorectal tissues. The mean protein expression level of SLC12A5 was significantly higher in primary CRCs as compared to their adjacent normal tissues. Amplification of SLC12A5 was detected in 40.8% (78/191) of primary CRCs by FISH, which was positively correlated with its protein overexpression (P < 0.001). Overexpression of SLC12A5 was positively associated with a more advanced TNM stage (P < 0.05). Multivariate Cox regression analysis showed that SLC12A5 overexpression was an independent predictor of poorer survival of CRC patients (P = 0.018). We further tested the biological function of SLC12A5 in human colon cancer cells. Ectopic expression of SLC12A5 in colon cancer cells SW480 and SW1116 increased proliferation and colony formation. Silencing SLC12A5 expression in HCT116 by siRNA had the opposite effects in vitro, and knockdown of SLC12A5 by shRNA significantly inhibited xenograft tumor growth in nude mice. We further revealed that SLC12A5 inhibited apoptosis of colon cancer cells by mediating apoptosis-inducing factor (AIF) and endonuclease G (EndoG) -dependent apoptotic signaling pathway. Moreover, gain-and loss-of-function experiments showed that SLC12A5 enhanced cell invasion and migration in vitro. Knockdown of SLC12A5 by shRNA significantly inhibited lung metastasis in nude mice. SLC12A5 promoted tumor metastasis through regulating key elements of the matrix architecture, such as matrix metallopeptidase and fibronectin. / Conclusion: We have identified a novel amplification gene SLC12A5 which is overexpressed in CRC. SLC12A5 may be an independent prognostic marker for CRC and may play a pivotal oncogenic role in colorectal carcinogenesis by inhibiting apoptosis and promoting metastasis. / 背景和目的:通過對結直腸癌進行全基因組測序,我們首次發現位於染色體20q13.12的SLC12A5基因在結直腸中擴增。本研究旨在探索SLC12A5在結直腸癌中的擴增情況和臨床意義,并進一步研究SLC12A5在結直腸癌發生發展中的作用機制。 / 材料和方法:採用免疫组化方法檢測SLC12A5的蛋白表达水平。應用熒光原位雜交方法驗證SLC12A5基因的擴增情況。在195例結直腸癌患者中对SLC12A5表达與临床病理關係及其對預後的影響其进行分析。通过檢測細胞活力、細胞集落形成實驗、侵襲實驗、遷移實驗、流式細胞術和體內成瘤實驗以研究SLC12A5在結直腸癌中的生物学功能。進而通過免疫印跡、熒光素酶報告實驗和人腫瘤轉移的PCR陣列,探索SLC12A5調控的基因和相关途径。 / 结果:我們採用RT-PCR方法檢測SLC12A5在9株結直腸癌細胞株的表達情況,SLC12A5在7株結直腸癌細胞株中穩定表達,但是在正常大腸組織中表達沉默。SLC12A5在結直腸中的平均蛋白表達水平顯著高於其鄰近的正常組織。通過熒光原位雜交方法,在40.8% (78/ 191)的結直腸癌中檢測到SLC12A5的擴增,該基因的擴增與其蛋白高表達水平呈正相關關係。SLC12A5高表達水平跟晚期TNM分期密切相關(P <0.05)。多因素Cox回歸分析表明,SLC12A5高表達是結直腸癌患者較差的生存的獨立預測因子(P = 0.018)。我們進一步在人結腸癌細胞株中檢測SLC12A5的生物功能。在結腸癌細胞SW480和SW1116中過度表達SLC12A5促進細胞增殖和集落形成。siRNA敲低HCT116 細胞SLC12A5的表達在體外實驗中有相反的效果。此外,shRNA敲低SLC12A5的表達顯著抑制裸鼠移植瘤的生長。我們進一步發現,SLC12A5通過介導凋亡誘導因子(AIF)和核酸內切酶G(EndoG)-依賴的細胞凋亡信號轉導通路抑制結腸癌細胞的凋亡。此外,功能獲得性和功能缺失性的體外實驗表明,SLC12A5促進腫瘤細胞的侵襲和遷移。尾靜脈注射實驗表明shRNA敲低SLC12A5的表達顯著抑制裸鼠肺轉移。SLC12A5通過調節基質結構的關鍵因子,如基質金屬蛋白酶和纖維連接蛋白,促進腫瘤轉移。 / 结论:我們發現了一個新的擴增基因SLC12A5,該基因在結直腸癌中高表達。SLC12A5是結直腸癌的一個獨立的預後標誌物。SLC12A5通過抑制細胞凋亡和促進腫瘤轉移,在結直腸癌的發生發展中起了舉足輕重的致癌作用。 / Xu, Lixia. / Thesis Ph.D. Chinese University of Hong Kong 2014. / Includes bibliographical references (leaves 107-120). / Abstracts also in Chinese. / Title from PDF title page (viewed on 05, October, 2016). / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only.
455

Indução do estado de portador renal e genital pela Leptospira interrogans sorovar Canicola, estirpe LO4 em hamster (Mesocricetus auratus). Influência da concentração, da virulência da estirpe, da via de inoculação e da vacinação / Induction of renal and genital carrier for Leptospira interrogans serovar Canicola, strain LO4, in hamster (Mesocricetus auratus). Influence of concentration, strain virulence, inoculation via and vaccination

Marchiori Filho, Moacir 14 December 2007 (has links)
Em decorrência da importância da leptospirose nas criações zootécnicas pelos prejuízos econômicos, principalmente pelas infecções crônicas, forma mais importante na propagação e permanência da bactéria no ambiente, este trabalho pretendeu estudar o curso da leptospirose e a formação do portador pela infecção experimental de hamsters com Leptospira interrogans sorvar Canicola, estirpe LO4, autóctone, pelas vias conjuntiva-nasal (CN) e cérvico-vaginal (CV) comparadas a via controle, intraperitonial (IP) com duas concentrações de inóculo (20-30 e 100-200 leptospiras/campo microscópico) e ainda estabelecer a eficácia conferida por cinco vacinas experimentais formuladas com dois tipos de adjuvantes (saponina e hidróxido de alumínio), pelo desafio de hamster. No preparo das vacinas foi considerada a virulência da estirpe LO4 submetida a duas e cinco passagens in vitro, que foi comparada com duas vacinas controle produzidas com a estirpe de referência, Hond Utrecht IV, com indeterminado número de passagens in vitro. Foram também avaliadas a indução de anticorpos aglutinantes e neutralizantes e as lesões histopatológicas por HE e Warthin-Starry. A detecção das leptospiras nos órgãos de hamsters mortos pela leptospirose ou eutanasiados foi realizada pela visualização direta, cultivo e PCR, considerando qualquer um dos resultados positivo. A visualização direta foi o melhor método de detecção na suspensão de órgãos. A via CN mostrou-se tão letal quanto IP na maior concentração de inóculo (p<0,01) e também mais letal que CV nas duas concentrações (p<0,01). A via CV induziu o portador renal e genital, não havendo diferença entre as duas concentrações. Pela via CN, não houve diferença entre sexos na indução da letalidade e da formação do portador, para ambos os inóculos. Todos os hamsters que morreram pós-inoculação apresentaram grande quantidade de leptospiras nos rins e genitais com necrose e hemorragias. Os animais eutanasiados após 21 dias de infecção, apresentaram leptospiras em rins e genitais sem lesões aparentes, caracterizando o portador. Pela SAM, tanto os animais que vieram a óbito, quanto os sobreviventes à inoculação com ambas as concentrações de leptospiras pelas vias CN, CV e IP, mostraram-se não reagentes na SAM (<25) para as estirpes LO4 e Hond Utrecht IV. As vacinas com ambas as estirpes e adjuvantes induziram baixos títulos de anticorpos aglutinantes e neutralizantes. Os maiores títulos de anticorpos neutralizantes e aglutinantes foram observados nos animais vacinados com a estirpe referência, Hond Utrecht IV. Os anticorpos neutralizantes não tiveram correspondência com o teste desafio em hamsters. As vacinas produzidas com ambas as estirpes protegeram os animais contra a letalidade da leptospirose causada pela infecção com a estirpe LO4, e, portanto a virulência da estirpe não interferiu na eficácia, porém as bacterinas não foram capazes de proteger os hamsters contra a formação do portador renal e genital. / Leptospirosis is important in production systems due to its negative economic impact, and chronic infections are the most relevant type of propagation and permanence of the bacteria in the environment. The objectives of this study were to study the occurrence of leptospirosis, and the formation of carriers animals, by the experimental infection of hamsters with Leptospira interrogans serovar Canicola, LO4 autochthon strain through conjunctive-nasal (CN) and cervix-vaginal (CV) via versus control and intra-peritoneum (IP) via with two inoculum concentrations (20-30 and 100-200 leptospiras/microscopic area). In addition, the efficacy of five experimental vaccines formulated with two types of adjuvants (saponine and aluminum hydroxide) was evaluated. In the vaccine preparation, the virulence of LO4 autochthon strain manipulated in two and five in vitro passages was compared with two control vaccines produced with the reference strain, Hond Utrecht IV with undeterminated number of in vitro passages. It was also evaluated the induction of agglutinating and neutralizing antibody production and the histopathological lesions by HE and Warthin-Starry. The leptospira detection in the hamsters organs killed by the leptospira or euthanized was done by direct visualization or culture or PCR. The direct visualization was the best method of detection in the organs suspensions. The CN via has shown to be as lethal as IP in the highest inoculum concentration (p<0.01) and also more lethal than the CV in the two concentrations (p<0.01). The CV via has induced the occurrence of renal and genital carrier with no difference between the two concentrations. By the CN via, with the two inoculum, there has no difference detected between sex in the lethality induction as well as in the formation of carrier. All hamsters that died following inoculation presented a great amount of leptospiras in the kidneys and genitals with necrosis and hemorrhage. After 21 days of infection, the euthanized animals presented leptospiras in the kidneys and genitals without any apparent lesion, characterizing a carrier. By the SAM, the animals that died, as well as the ones that survived the inoculations by CN, CV and IP via with the two inoculum concentrations were not reactive to the SAM (<25) to the strain LO4 and Hond Utrecht IV. The two vaccines for the two strains and adjuvant have induced low agglutinating and neutralizing antibody titers. The highest agglutinating and neutralizing antibody titers were observed in animals vaccinated with the reference strain, Hond Utrecht IV. The neutralizing antibodies did not correspond to the hamster challenge test. The two vaccines produced with the two strains protected the animals against the leptospira lethality caused by the LO4 strain; therefore, the strain virulence did not affect the efficacy. However, the bacterines were not capable to protect the hamsters against the formation of renal and genital carrier.
456

Characterization of phase state, morphological, mechanical and electrical properties of nano- and macro-dimensional materials

Ray, Kamal Kanti 01 August 2019 (has links)
The importance of studying the physico-chemical properties of nano-dimensional materials has gained significant attention in the fields of semiconductors, pharmaceuticals, materials science, and atmospheric chemistry owing to the differences in physical properties between macro- and nano-dimensional solids. Nonetheless, direct studies of physical properties of materials at nanoscale is limited in part due to their inherent size constraints and experimental limitations. However, development of atomic force microscopy (AFM) led to the implementation of methods to characterize a wide range of physical properties, including – but not limited to – mechanical properties, electrical properties, viscoelastic properties, and surface tension. Herein, the dissertation focuses on AFM-based method development for characterization of atmospheric particles as well as understanding the relationship between structure and physical properties of organic solids at both macro- and nano-dimensions. In the atmospheric chemistry realm, the combined aerosol effect on the climate and environment has significant uncertainty in part due to lack of direct characterization of their physico-chemical properties. The difficulty in assessing the physical and chemical properties arises due to the presence of diversified aerosol sources, which in turn influences the size, morphology, phase states and chemical compositions. Sea spray aerosols (SSAs) are the second-largest source of aerosols in the atmosphere. Studying SSAs – especially in submicrometer-dimensions – requires high-resolution microscopy techniques such as AFM. AFM can be used for imaging of individual aerosols, quantifying organic volume fraction for core-shell morphologies, measuring water uptake, quantifying surface tension of individual droplets, and measuring mechanical and viscoelastic properties of materials. Herein, we employed AFM-based morphology and force spectroscopy studies to correlate the 3D morphology, phase state, and viscoelastic properties of selected single-component chemical systems found in sea spray aerosol (SSA). We established a quantitative framework toward differentiation of the solid, semisolid and liquid phase states of individual particles by utilizing both relative indentation depth (RID) and viscoelastic response distance (VRD) data obtained from the force−distance plots. Moreover, we established a semi-quantitative and quick phase assessment by measuring the aspect ratio (AR) that refers the extent of particle spreading as a result of impaction. Overall, the established AFM-based quantitative and semi-quantitative phase identification method can be utilized to assess the phases of aerosols irrespective of chemical identity. Next, we investigated the factors that may control the electrical and mechanical properties of pharmaceutical and organic semiconducting materials in nano- and macro-dimensions. Understanding the structure-property relationship of materials, especially in the nano-dimension, is necessary for proper drug design and development of organic semiconducting materials. In this context, cocrystals provide a means to modulate the physico-chemical properties of organic solids. For example, the modulation of the mechanical properties is important in the pharmaceutical industry for improving the tabletability. The mechanical properties may be affected by packing arrangement, interaction strength and type, and atomic and chemical composition. Herein, we report the influence of alkane and alkene functional groups on the mechanical properties of organic solids based on salicylic acid (SA). The approach affords both isostructural and polymorphic solids. The isostructural alkane functional solid exhibits a two-fold larger Young’s modulus (YM) compared to the cocrystal with the alkene, where the YM refers to the stiffness of the material. Here, the higher YM values are attributed to the presence of a bifurcated weak C-H···O interactions involving the alkane and neighboring SA molecules. On the other hand, in the case of alkene polymorphisms, molecular packing with column arrangement shows higher YM values compared to the herringbone arrangements. Thus, functional groups and crystal arrangements influence the stiffness of the solid organic cocrystals. Moreover, we report the modulation of mechanical properties of salicylic acid (SA) through cocrystallization by variation of propane and butane functionality with bipyridine coformers. We show that the variation of propane and butane functionality in bipyridine coformer with salicylic acid leads to synthesis of cocrystal and salt-cocrystal, respectively. The AFM nanoindentation study revealed that the Young’s modulus values follow the order salicylic acid < cocrystal << salt-cocrystal. The highest Young’s modulus values of the salt-cocrystal, among the studied systems, are attributed to the presence of strong N+–H···O– and O–H···O– interactions. On the other hand, higher Young’s modulus values of the propane-based cocrystal compared to the macro-dimensional salicylic acid are attributed to the stronger O–H ···N hydrogen bonding. Thus, homologous alkane functional groups can influence the mechanical properties of the organic solid crystals. Additionally, in situ solid-solid polymorphic phase transformation and nucleation of a metastable and elusive polymorph of SA cocrystals in combination with 4,4’-bipyridine were studied. Understanding the solid-solid phase transformations and nucleation mechanisms are important for proper control over the parameters associated with the synthesis of targeted crystalline solids with desired crystal structure. Using in situ powder X-ray diffraction (PXRD) and terahertz time domain spectroscopy (THz-TDS) data we showed that the Form II polymorph transforms to Form I over time. AFM imaging and nanoindentation techniques were utilized to follow and quantify in real-time the solid-solid polymorphic transformation of the metastable Form II to the thermodynamically stable Form I on a single crystal basis. AFM in situ single crystal data revealed that the metastable Form II has a rod-shaped morphology and relatively high elasticity (Young’s modulus), which transforms to prism-shaped nanocrystals of much smaller sizes with significantly reduced elasticity. The AFM imaging reveals that the single crystals on the order of 80-150 nm to undergo catastrophic changes in morphology that are consistent with cracking and popping owing to a release of mechanical stress during the transformation. The nucleation mechanism for the polymorphic transformation is not spatially localized and occurs over the entire crystal surface. The higher mechanical properties of the metastable Form II is due to the presence of the additional interlayer C-H···O interactions. Furthermore, we have studied the electrical properties of boron-based cocrystals. More specifically, cocrystallization of a nonconductive 2,4-difluorophenylboronic ester catechol adduct of a 4,4’-bipyridine (BEA) host with two aromatic semiconducting guests (pyrene and tetrathiafulvalene) generated conductive cocrystals with variable charge carrier mobilities. Charge carrier mobilities of the cocrystals with either pyrene or tetrathiafulvalene were measured using conducting probe AFM (CP-AFM). The incorporation of π-rich aromatic guests through face-to-face and edge-to-face π-contacts results in electrically conductive cocrystals. The cocrystal with tetrathiafulvalene as a guest shows approximately 7 times higher charge carrier mobility than the cocrystal with pyrene. Overall, the current dissertation demonstrates the AFM-based method development and applications towards materials characterization to measure the morphological, electrical, mechanical, and phase-states at both nano- and macro-dimensions. The high spatial precision of the methods developed enables us to better understand the controlling factors for materials design and processing across nano- and macro-dimensions.
457

Photocatalysis and Grazing-Ion Beam Surface Modifications of Planar TiO2 Model Systems

Luttrell, Timothy 04 April 2014 (has links)
This dissertation is related to the understanding of catalytic reactions of metal oxides. For several decades, the surfaces and bulk of materials have been probed to determine additional properties that relate to photocatalytic applications. This investigation furthers these efforts by the (a) modification of a metal oxide surface to isolate known influences of chemical properties and (b) proposing and utilizing a novel methodology for attribution of photocatalytic activity to a discernable influence. For the first effort, by effectively utilizing a known technique for a new application on a metal oxide, such isolations can be made despite unfavorable states. For the second effort, a reduction in the influence of surface states for metal oxides is effectively performed, providing the isolation of influences originating from the bulk. The challenge with such a proposal is verifying such bulk states have been adequately isolated as external influences would obviously distort any conclusions. Thus, techniques to both create such bulk states and eliminate unwanted combinations thereof are additionally required and must be provided for. Lastly, a determination of the photocatalytic activity is made to these states and results are provided.
458

Visualizing Carrier Aggregation Combinations

Helders, Fredrik January 2019 (has links)
As wireless communications is becoming an increasingly important part of ourevery day lives, the amount of transmitted data is constantly growing, creating ademand for ever-increasing data rates. One of the technologies used for boostingdata rates is carrier aggregation, which allows for wireless units to combine multipleconnections to the cellular network. However, there is a limited number ofpossible combinations defined, meaning that there is a need to search for the bestcombination in any given setup. This thesis introduces software capable of organizingthe defined combinations into tree structures, simplifying the search foroptimal combinations as well as allowing for visualizations of the connectionspossible. In the thesis, a proposed method of creating these trees is presented,together with suggestions on how to visualize important combination characteristics.Studies has also been made on different tree traversal algorithms, showingthat there is little need for searching through all possible combinations, but thata greedy approach has a high performance while substantially limiting the searchcomplexity. / I samband med att trådlösa kommunikationssystem blir en allt större del av våraliv och mängden data som skickas fortsätter att stiga, skapas en efterfrågan förökade datatakter. En av teknologierna som används för att skapa högre datatakterär bäraraggregering (carrier aggregation), som möjliggör för trådlösa enheteratt kombinera flertalet uppkopplingar mot det mobila nätverket. Det finns dockbara ett begränsat antal kombinationer definierade, vilket skapar ett behov av attsöka upp den bästa kombinationen i varje givet tillfälle. Detta arbete introducerarmjukvara som organiserar dessa kombinationer i trädstrukturer, vilket förenklarsökning efter optimala kombinationer tillsammans med möjligheten att visualiserade potentiella uppkopplingarna. I arbetet presenteras en föreslagen metodför att skapa dessa träd, tillsammans med uppslag på hur viktiga egenskaperhos kombinationerna kan visualiseras. Olika trädsökningsalgoritmer har ocksåundersökts, och det visas att det inte är nödvändigt att söka igenom hela träd.Istället visar sig giriga algoritmer ha hög prestanda, samtidigt som sökstorlekenkan hållas kraftigt begränsad.
459

Carrier Dynamics in InGaAs/GaAs Quantum Dots Excited by Femtosecond Laser Pulses

Chauhan, Kripa Nidhan 01 May 2013 (has links)
Ultrafast carrier dynamics studies have been carried out on samples with single layers of self-assembled In0.4Ga0.6As/GaAs quantum dots (QDs). Measurements were made using femtosecond degenerate pump-probe differential reflectivity with an 800-nm, 28-fs Ti-sapphire oscillator as the source. The QDs were grown via modified Stranski-Krastanov growth. This modified growth process consists of two steps: low-temperature growth and high-temperature annealing. Specifically, the InGaAs QD structures are fabricated on n-type GaAs(001) using molecular beam epitaxy. The InGaAs layer is deposited at 350-3700C followed by QD self assembly at 420-4900C. Finally, these QDs are capped with 10 nm or 100 nm of GaAs. The measured width and height of these QDs are typically 25 nm and 8 nm, respectively. Dots annealed at higher temperature have larger base area (width and length) and reduced height, as compared to those annealed at lower temperature. We have used a model consisting of a linear combination of an exponential decaying function to describe the carrier dynamics and fit the reflectivity data, revealing trends in the carrier capture and relaxation times associated with the InGaAs layer versus laser excitation level and QD morphology. Capture times are ~ 1 ps for the 100-nm capped samples, but slightly shorter for the 10-nm capped thin samples, indicating carrier transport plays a role in dynamics. The carrier dynamics in 10-nm capped samples are correlated with sample annealing temperature, indicating QD morphology affects carrier capture. Versus laser intensity, and thus carrier excitation level, the dynamics generally become slower, suggesting state filling is important in both the capture and relaxation of excited carriers in these samples.
460

Die Rolle der Glukosetransporter an der Blut-Hirn-Schranke nach einem Schädel-Hirn-Trauma und deren eventueller Einfluss auf die Entwicklung eines sekundären Hirnödems / The role of the glucose transporters after traumatic brain injury and their influence on the development of secondary brain edema

Wais, Sebastian January 2012 (has links) (PDF)
Laut der Weltgesundheitsorganisation (WHO) waren in Deutschland 2006 akute ischämische Ereignisse des Zentralen Nervensystems (ZNS) die fünfthäufigste Todesursache. Zu diesen ischämischen Ereignissen zählen Schlaganfall, Kardiopulmonale Reanimation, traumatische Hirnverletzungen, sowie perioperative ischämische Komplikationen. Aufgrund der schwerwiegenden Folgen, die ein Verlust von Nervenzellen für den Patienten bedeutet, muss die weitere medizinische Akutversorgung den sekundären neuronalen Schaden verhindern oder ihn reduzieren. Vor dieser Arbeit konnten Glukosetransporter-1 (GLUT-1) und Natrium-Glukose-Kotransporter-1 (SGLT1) an der Blut-Hirn-Schranke (BHS) identifiziert werden. Ziel dieser Arbeit war es, das Expressionsverhalten der Glukosetransporter nach einem Schädel-Hirn-Trauma (SHT) in vivo und in vitro zu untersuchen, um so den Einfluss und die funktionellen Folgen durch die veränderte Expression der zerebralen Glukosetransporter in der BHS infolge eines SHT zu identifizieren und deren eventuellen Einfluss auf die Entwicklung eines sekundären Hirnödems zu erkennen. Hierfür wurde als in vivo-Modell das Controlled Cortical Impact Injury (CCII) gewählt, da bei diesem Tierversuchsmodell die Aspekte der traumatischen Kontusion und die damit verbundenen intraparenchymalen Blutungen durch ein epidurales oder subdurales Hämatom im Vordergrund stehen. Es wurden Gehirnschnitte zu fest definierten Zeitpunkten angefertigt (kein CCII (Kontrolle), 15 Minuten Überleben nach CCII (Primärschaden), 24 Stunden Überleben nach CCII und 72 Stunden Überleben nach CCII). Die Darstellung des primären Schadens im Mäusehirn erfolgte durch die Immunfluoreszenzmikroskopie. Um einen Gewebeschaden, wie es bei einem Hirntrauma der Fall ist, in vitro zu simulieren, wurde das Modell des Sauerstoff-Glukose-Entzuges (OGD) gewählt, da es bei diesem Modell neben einer Nekrose auch zur Apoptose der Nervenzellen kommt, welche ebenfalls bei einem SHT stattfindet. Als geeignetes Zellkulturmodell wurde die cerebralen Endothelzelllinie (cEND) gewählt. Bei dieser Zelllinie handelte es sich um eine Hirnendothelzelllinie aus der Maus. In den in vivo-Versuchen konnte bei GLUT-1 bereits 15 Minuten nach CCII eine gesteigerte Expression festgestellt werden. Dennoch verminderte GLUT-1 im weiteren Verlauf seine Expression auf ein Minimum, welches unterhalb des Ausgangswertes lag. SGLT1, der auch in der BHS identifiziert wurde, reagierte auf einen Primärschaden erst in den Hirnschnitten, die 24 Stunden nach CCI behandelt wurden. In den Hirnschnitten, die 15 Minuten nach CCII behandelt wurden, veränderte sich die SGLT1-Expression zunächst nicht. Erst 24 Stunden nach CCII konnte eine gesteigerte Expression von SGLT1 erkannt werden, die aber bei 72 Stunden nach CCII wieder abgenommen hatte. Ein weiterer Glukosetransporter konnte erstmals in der BHS identifiziert werden. SGLT2 zeigte erst 72 Stunden nach CCII eine gesteigerte Expression, in den Hirnschnitten ohne CCII, 15 Minuten nach CCII und 24 Stunden nach CCII konnte keine Veränderung der SGLT2-Expression festgestellt werden. Diese Expressionsreaktion, besonders der Expressions-Höhepunkt der einzelnen Glukosetransporter, konnte auch in vitro gezeigt werden. Besonders die Identifizierung von SGLT2 in der BHS und die generelle Steigerung der Expressionsrate von GLUT-1, SGLT1 und SGLT2 könnte neue Ansatzpunkte in der Pathophysiologie des diffusen Hirnödems nach einem SHT ergeben. Die genaue Rolle der Natriumgekoppelten Glukosetransporter in der BHS muss noch weiter erforscht werden. Bestätigen weitere Versuche eine zentrale Rolle der SGLTs bei der Entstehung des sekundären Hirnschadens, speziell SGLT2, als hochpotenter Glukosetransporter, so könnte über neue Therapien nachgedacht werden, durch welche spezifisch die Expression der SGLTs, besonders SGLT2, wie es bei Dapagliflozin, Canagliflozin oder Ipragliflozin der Fall wäre, unterdrücken würden. / According to the World Health Organization (WHO) the acute ischemic events of the central nervous system (CNS) were the fifth most common mortality in Germany in 2006. To this belong stroke, cardiopulmonary resuscitation, traumatic brain injuries, as well as perioperative ischemic complications. Because of the fatal consequences for a patient which means a death of nerve the medical acute care must be prevent the secondary neuronal damage. Before this work the glucose transporter 1 (GLUT-1) and sodium-glucose cotransporter-1 (SGLT1) are identified at the blood-brain barrier (BBB). The aim of this study was to analyze the expression characteristics of the glucose transporters after a traumatic brain injury (TBI) in vivo and in vitro. These results may show the influence and the functional consequences of the altered expression of cerebral glucose transporters in the BBB as a result of TBI. This allows to recognize a potential impact on the development of cerebral edema. We use for this the model of the controlled cortical impact injury (CCII) as an in vivo model. Brain trauma was induced and animals were randomly assigned to three survival groups: 15 min, 24 h and 72 h, which were compared to native – no CCII – animals. The depiction of the primary damage in mouse brain was performed by immunofluorescence microscopy. To simulate the tissue damage in vitro we use the model of oxygen-glucose deprivation (OGD). As a suitable cell culture model of the cerebral endothelial cell line (cEND) was chosen. In this cell line, there was a cerebrum endothelium cells of the capillary endothelium from the mouse brain. In summary, immunofluorescence images revealed presence of sglt1 and sglt2 in the blood-brain barrier which was inducible by CCII. Strongest expression of sglt1 in the brain endothelium was found after 24 hours and of sglt2 after 72 hours after CCII suggesting different and time dependent roles of these two transporters during edema formation. This expression, especially the expression peak of the individual glucose transporter could be also demonstrated in vitro model. In particular, the identification of SGLT2 in the BBB and the general increase of the expression of GLUT-1, SGLT1 and SGLT2 might be a new starting point in the pathophysiology of diffuse cerebral edema. Indicate further experiments a central role of SGLTs in the development of secondary brain damage, particularly SGLT2, as an highly potent glucose transporter, it could be given to new therapies through which suppress specific the expression of SGLT2.

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