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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.
71

Immunomodulatory actions of vitamin D in the protection against acute respiratory infections

Greiller, Claire Louise January 2014 (has links)
Introduction: Vitamin D is a micronutrient that possesses immunomodulatory actions. Higher vitamin D status has been associated with decreased incidence of acute respiratory infections (ARI) in a number of observational studies. However, mechanistic in vitro work investigating effects of vitamin D on the immune response to ARIs is lacking, especially for rhinovirus, which is the most common respiratory pathogen. Results of clinical trials of vitamin D supplementation in the prevention of ARIs have also been conflicting, in that some demonstrate a protective effect of this intervention against ARI, while others do not. Methods: An immunological assay of ex vivo stimulation with TLR ligands and pathogens in blood samples from participants with asthma, COPD or neither condition in three randomised controlled trials of vitamin D supplementation for the prevention of ARI and exacerbations was developed. This assay was used in conjunction with cellular profiling of clinical trial blood and sputum samples, and a rhinovirus-infected human alveolar cell line (A549 cells) to determine the effects of vitamin D in the protection against acute respiratory infections. Results: The main finding of cell culture experiments was that A549 cells pre-treated with physiological concentrations of 25-hydroxyvitamin D (25[OH]D, the major circulating vitamin D metabolite) had increased resistance to rhinovirus infection, which was associated with attenuation of rhinovirus-induced intercellular adhesion molecule-1 (ICAM-1) and platelet-activating factor receptor (PafR) expression. Immunological analysis of clinical trial samples did not demonstrate any consistent effect of bolus-dose vitamin D supplementation on circulating or pathogen-stimulated inflammatory profiles, or on inflammatory indices in induced sputum. Conclusions: Co-incubation with 25(OH)D was associated with transient protection against rhinovirus infection in a respiratory epithelial cell line in vitro, but these findings did not translate to any changes in cellular profile or inflammatory mediator release in clinical trials samples following in vivo vitamin D supplementation.
72

Ponto de corte para adequação da concentração sérica de 25 hidroxivitamina D em adultos e idosos: estudo de base populacional - ISA-Capital / Cutoff or adequacy of serum 25-hydroxyvitamin D in adults and elderly: populationbased study ISA-Capital.

Frota, Karine de Holanda 29 August 2012 (has links)
Introdução - A concentração sérica de vitamina D pode variar em indivíduos de diferentes grupos etários e de diversas regiões geográficas e pode ser influenciada pela exposição solar, estação do ano, bem como pelos valores de IMC e paratormônio (PTH). A classificação utilizada para definir concentração sérica adequada de vitamina D refere valores de 25(OH)D acima de 30 ng/mL. Porém, essa classificação pode estar inapropriada para a população brasileira, devido às particularidades climáticas e alimentares. Objetivo - Verificar as concentrações séricas médias de 25(OH)D e PTH e sua relação com IMC, exposição solar e estação do ano e identificar os valores de corte da 25(OH)D associados à elevação do paratormônio (PTH) em adultos e idosos de amostra representativa da população do município de São Paulo. Métodos - Para esta dissertação foi desenvolvido um artigo original. O artigo original descreve o estudo transversal realizado com indivíduos do estudo ISA-Capital, estudo multicêntrico e de base populacional, onde foram investigados 589 indivíduos, de ambos os sexos, dos grupos etários: 20 a 59 (adultos) e 60 e mais (idosos). Foram coletadas amostras de sangue, para dosagens de 25(OH)D e PTH. Os indivíduos que aceitaram participar da coleta de sangue, também responderam um questionário sobre exposição solar. A análise estatística incluiu a curva ROC, testes t de Student, correlação e ANOVA. Os cálculos foram realizados pelo software SPSS versão 17.0. e p 0,05 foi considerado significante. Resultados - No artigo original observou-se idade média de 54,83 (19,21) anos, sendo 61,3 por cento do sexo feminino e 38,7 por cento do sexo masculino. A concentração sérica média de 25(OH)D foi 50,02 (22,69) ng/mL, já entre os grupos foi de 47,48 (23,03) (adultos) e 52,68 (22,06) ng/mL (idosos) havendo diferença significativa entre eles (p=0,005). Observou-se variação sazonal da concentração sérica de 25(OH)D e correlação positiva entre 25(OH)D e IMC (r = 0,114, p = 0,006). O novo valor de corte 55.8 ng/mL, determinado pela análise da curva ROC, encontrou 67,6 por cento dos indivíduos insuficientes de 25(OH)D e entre os grupos 72,1 por cento (adultos) e 62,8 por cento (idosos). Conclusão - Os resultados demonstram a presença de variação sazonal nas concentrações séricas de 25(OH)D no municipio de São Paulo. O ponto de corte proposto para nossa população indicou elevada prevalência de insuficiência de vitamina D. Portanto, se faz necessário políticas públicas de prevenção de insuficiência de vitamina D visando os efeitos benéficos na saúde e qualidade de vida desta população. / Introduction - The serum concentration of vitamin D may vary in individuals of different age groups and geographic regions and may be influenced by sun exposure, season and by BMI and parathyroid hormone (PTH). The classification widely used as a cut-off for appropriate vitamin D status refers serum 25 (OH) D above 30 ng/mL. However, this classification may be inappropriate for the Brazilian population, due to the particular food and the climate of our population. Objective - To determine the mean serum concentrations of 25(OH)D and PTH and correlate them with BMI, sunlight exposure and season and to identify the cutoff values of 25 (OH) D associated with elevation in PTH. Methods For this dissertation, one original article were developed. Original article describe cross-sectional study performed with subjects from the ISA Capital, multicenter population-based. We investigated 589 individuals were of both sexes, age groups: 20-59 (adults) and 60 (elderly). Blood samples for laboratory measurements of 25(OH)D and PTH were collected. Individuals, who agreed to participate in blood collection, also answered a questionnaire on sunlight exposure. Statistical analysis included ROC curve, Student t test, correlation tests, ANOVA. The calculations were performed by the software SPSS version 17.0. and p 0.05 was considered significant. Results - In the original article, the mean age of participants was 54.83 (19.21) years, 61.3 per cent female and 38.7 per cent were male. The mean serum 25 (OH) D was 50.02 (22.69) ng/mL, between the groups was 47.48 (23.03) (adults) and 52.68 (22.06) ng/ mL (elderly) and significant difference between them (p = 0.005). A seasonal variation in serum 25 (OH) D was observed and positive correlation between 25(OH)D and BMI (r = 0.114, p = 0.006). The new cutoff value 55.8 ng / mL, determined by ROC curve analysis found 67.6 per cent of subjects insufficient 25 (OH) D and between groups 72.1 per cent (adults) and 62.8 per cent (elderly). Conclusion - The results demonstrate the presence of seasonal variation in serum 25 (OH) D in the municipality of Sao Paulo. The cutoff point proposed for our population showed a high prevalence of insufficient vitamin D. Therefore, public policy is needed to prevent vitamin D insufficiency in order to beneficial effects on health and quality of life in this population.
73

Projeto de um conversor analógico-digital para um receptor Bluetooth em tecnologia CMOS. / Analog to digital converter design for a Bluetooth receiver in CMOS technology.

Carvajal Ossa, Wilmar 03 December 2010 (has links)
Neste trabalho aborda-se o projeto de um conversor analógico-digital (ADC) que deve atingir as especificações do padrão Bluetooth. Este bloco faz parte do estágio de recepção de um transceptor sem fio integrado em tecnologia CMOS. Inicialmente é feita a análise do ADC como sistema, ao mesmo tempo que as especificações nesse nível são desenvolvidas. A arquitetura adaptada da literatura é conhecida como time-interleaved pipeline. Os seus principais blocos, o S&H e o estágio básico incluindo o sub-ADC e o MDAC, são explicados posteriormente junto com a estratégia de correção digital através do bit de redundância entre estágios consecutivos. Seguindo essa ordem de ideias, é estudada a implementação com portas digitais da estratégia anterior e da geração das fases de relógio necessárias para os blocos da cadeia pipeline. Os dois circuitos mais elementares, o amplificador operacional de transcondutância (OTA) e o comparador de tensão, também são apresentados antes de introduzir a programação geométrica como ferramenta de projeto auxiliar. Tal ferramenta permite otimizar o consumo de potência desses circuitos básicos e, portanto, descobrir uma nova perspectiva no projeto de circuitos analógicos do estado da arte. Finalmente, os resultados obtidos e as simulações dos diferentes blocos e circuitos que constituem o ADC são mostrados. Esses resultados também incluem as medições e testes feitos em um OTA projetado com PG e fabricado em tecnologia CMOS 0,35 micrômetros. A conclusão mais importante deste trabalho se deriva da aplicação simultânea da programação geométrica e a análise cuidadosa dos requisitos reais dos circuitos, levando portanto à otimização do desempenho global do ADC projetado. / In this work, an Analog to Digital Converter (ADC) fulfilling the Bluetooth standard specifications is designed. This block stays at the reception side of an integrated wireless transceiver in CMOS technology. Initially, an analysis of the ADC as a system is carried out, at the same time that the specifications at that level are developed. The architecture adapted from the literature is known as time-interleaved pipeline. Its main blocks, the S&H and the basic cell including sub-ADC and MDAC circuits, are then explained together with the digital correction strategy based on the bit of redundancy between consecutive stages. Furthermore, digital gate implementation of previous strategy and generation of the different clock phases required by pipeline chain blocks, are covered. The two most elementary circuits, operational transconductance amplifier (OTA) and voltage comparator, are also presented before introducing geometric programming (PG) as an auxiliary design tool. Such a tool allows the power consumption optimization of these basic circuits and thus leads to a new perspective in analog circuit design for the state of the art. Finally, the reached results and the different ADC block simulations are presented. Those results include tests and measurements of an OTA designed using PG and fabricated in a CMOS 0,35 micrometers technology. The most important conclusion of this work is derived from the joint application of geometric programming and careful analysis of the real circuit requirements, allowing the global performance optimization in the designed ADC.
74

Outsiders in Red Rock Country : the Kaiparowits Project and the reputation of American environmentalism

Blower, Nicholas January 2018 (has links)
This dissertation interrogates the ways in which a series of critical newspapers, federal agencies, and private industries sought to re-shape and negatively frame the public image of post-war conservation and environmental groups in Utah and the Intermountain West. It traces, through a series of environmental-energy conflicts located around southern Utah's Kaiparowits Plateau, how commentators employed attacks on public image to de-legitimise and contain what was seen as the escalating spread of a political and cultural force: environmentalism. Beginning in the early 1950s and proceeding through much of the United States' 'environmental decade,' I detail the mutating nature and variable efficacy of these attacks as environmentalists were alternately associated with Communism, Middle Eastern oil cartels, and the counterculture. Recognising environmental groups as co-producers in this shifting public image, I also account for their counter-attempts at defending their reputations using advertising, photography, and promotional materials. This project offers a revisionist approach to standard narratives of the ascendancy of environmental organisations. Historical accounts have typically focused on the increasing competency, professionalism, and popularity of these advocacy groups. However, few explorations have focused on the way public understandings of the movement were shaped by a range of hostile critics that constructed environmentalists in a series of decidedly pejorative frames. I argue that even as several environmental organisations achieved increased political access and potency in the years 1950-1980, their reputations in the same period experienced a comparable decline. This resultant divisive reputation in the Intermountain states would come to play a central factor in the movement's subsequent loss of political and cultural agency in the region in the 1980s.
75

Vitamin D status and cardiometabolic risk factors in black African and Indian populations of South Africa

George, Jaya Anna 09 September 2014 (has links)
Background: South Africa is in the midst of a health transition that is characterized by a high burden of both infectious diseases and non-communicable diseases. One of the drivers of non-communicable diseases in South Africa is the current epidemic of obesity. Vitamin D deficiency, which is defined by 25(OH)D levels in blood, has been reported to be a risk factor for cardiovascular disease and shares a number of risk factors with those traditionally linked to non-communicable diseases. Osteoporosis is another non-communicable disease that is reportedly increasing in prevalence worldwide and may be linked to vitamin D levels and to body fat. There is limited data on 25(OH)D levels in South Africa and its association with cardiovascular risk factors. There is also limited data on body composition including bone mineral density. Aims: The aims of this thesis were to describe 25(OH)D levels in healthy Black African and Indian subjects recruited from the greater Johannesburg metropolis and to determine if differences in 25(OH)D levels contributed to differences in cardiovascular risk. A further aim was to describe body composition in both ethnic groups and to see if differences in body composition contribute to differences in 25(OH)D levels or to differences in bone mineral density and to determine if differences in bone mineral density are mediated by differences in 25(OH)D. Methods: This was a cross sectional study carried out from July 2011 to March 2012 on 714 male and female subjects (male: female=340:374) of whom 371 were Black African and 343 were Indian. Subjects were recruited via the caregivers of the Birth to Twenty cohort. The first step was a descriptive analysis of 25(OH)D as well as its predictors including whole body fat, visceral and subcutaneous adiposity. This was followed by examining the associations of 25(OH)D and parathyroid hormone with cardiovascular risk factors that comprise the metabolic syndrome. Final analysis was description of bone mineral density according to ethnicity and gender and the contribution of lean mass, sub-total fat mass, visceral and subcutaneous adiposity to bone mineral density in each ethnic group. Results: Vitamin D deficiency was very prevalent in Indians, 28.6% in comparison to 5.1% in the Black African group (p<0.0001). In both groups season of collection was a positive predictor and PTH was negatively associated with 25(OH)D. Neither whole body fat nor visceral or subcutaneous adiposity was predictive of 25(OH)D in either group. Using the harmonized definition of the metabolic syndrome (Met S), was diagnosed in 29% of the Black African and 46% of the Indian subjects (p<0.0001). Subjects with Met S had higher PTH than those without (p<0.0001), whilst 25(OH)D levels were not significantly different (p=0.50). Logistic regression analysis showed that Indian ethnicity (OR 2.24; 95% CIs 1.57, 3.18; p<0.0001) and raised PTH (OR 2.48; 95% CIs 1.01, 6.08; p=0.04) adjusted for 25(OH)D) produced an increased risk of Met S but 25(OH)D did not (OR 1.25; 95% CIs 0.67, 2.24; p=0.48). Whole body, hip, femoral neck and lumbar spine bone mineral density were significantly higher in Black African than Indian subjects (p<0.001 for all). Whole body lean mass positively associated with bone mineral density at all sites in both ethnic groups (p<0.001 for all), and partially explained the higher bone mineral density in Black African females compared to Indian females. Whole body fat mass correlated positively with lumbar bone mineral density in Black African (p=0.001) and inversely with sub-total bone mineral density in Indian subjects (p<0.0001). Visceral adiposity correlated inversely with sub-total bone mineral density in the Black African subjects (p=0.037) and with lumbar bone mineral density in the Indian group (p=0.005). No association was found between serum 25(OH)D and bone mineral density. PTH was inversely associated with hip bone mineral density in the Black African group (p=0.01) and with sub-total (p=0.002), hip (p=0.001) and femoral bone mineral density (p<0.0001) in the Indian group. Conclusions: This study highlighted the high prevalence of vitamin D deficiency in the Indian population and the fact that local conditions such as sunshine exposure and season of collection of blood are important determinants of 25(OH)D levels. It also showed that Indian ethnicity and PTH are risk factors for the Met S, but differences in risk between both ethnic groups are not due to differences in 25(OH)D levels. The thesis also showed that there are significant differences in bone mineral density across ethnicity, with lean mass an important contributor to bone mineral density across race and gender.
76

Concentrações séricas de vitamina D em lactentes saudáveis / Serum vitamin D concentrations in healthy infants

Almeida, Ane Cristina Fayão 26 January 2018 (has links)
Introdução: Uma elevada prevalência de deficiência de vitamina D (DVD) em crianças tem sido observada em todo o mundo, mas poucos são os estudos com relação ao estado nutricional da vitamina D (VD) em lactentes saudáveis. A principal causa da deficiência em crianças saudáveis é o aleitamento materno sem suplementação e a falta ou insuficiência de exposição solar. Objetivos: Determinar as concentrações séricas de VD e verificar sua associação com concentrações de paratormônio (PTH), fosfatase alcalina (FA), cálcio (Ca), fósforo (P) e albumina e uso da suplementação de VD em lactentes saudáveis com idades entre >= 6 e <= 24 meses atendidos em duas Unidades Básicas de Saúde do município de Ribeirão Preto, SP, Brasil. Métodos: Estudo transversal, observacional e analítico em que foram determinadas as concentrações séricas de 25 (OH)D, PTH, FA, Ca, P e albumina de 155 lactentes saudáveis. Informações sobre exposição solar, aspectos sociodemográficos das mães e características clínico-nutricionais dos lactentes foram obtidas por entrevistas com os responsáveis dos lactentes. Concentrações séricas de 25(OH)D maiores que 20ng/ml foram consideradas adequadas, entre 12 a 20ng/ml insuficientes e < 12ng/ml deficientes. Resultados: Dez lactentes (6,5%, Intervalo de Confiança 95% 3,5-11,4) apresentaram insuficiência de VD e nenhum apresentou DVD. Nenhuma alteração nas concentrações séricas de P, Ca e albumina foram detectadas. Apenas um lactente apresentou aumento nas concentrações séricas de PTH e 35,5% dos lactentes apresentaram FA elevada, porém nenhum apresentou DVD ou insuficiência de VD. Não foram encontradas associações entre as concentrações séricas de 25(OH)D e as de FA, Ca e albumina. Houve associação entre concentrações séricas de 25(OH)D e PTH mesmo após ajuste para sexo, idade e Índice de Massa Corporal; também foi observada associação entre concentrações séricas de 25(OH)D e P apenas após o ajuste pelas covariáveis. Não foram verificadas associações entre insuficiência de VD, exposição solar e suplementação de VD. Conclusões: Uma baixa prevalência de concentrações insuficientes de 25(OH)D foi observada. Não foram encontradas associações entre as concentrações séricas de 25(OH)D e PTH, FA, Ca, P e albumina. Da mesma forma, não foram encontradas associações entre de concentrações séricas de 25(OH)D, exposição solar e suplementação de VD. / Introduction: A high prevalence of vitamin D deficiency (VDD) in children has been observed worldwide, but there are few studies on the nutritional status of vitamin D (VD) in healthy infants. The main cause of deficiency in healthy children is breastfeeding without supplementation and lack or insufficiency of sun exposure. Objective: To determine serum concentrations of VD and verify its association with parathyroid hormone (PTH) levels and use of VD supplementation in healthy infants aged >= 6 to <= 24 months attended at two Basic Health Units in Ribeirão Preto city, São Paulo, Brazil. Methods: A cross-sectional, observational and analytical study was performed in which were determined serum concentrations of 25 (OH) D, PTH, alkaline phosphatase (AP), calcium (Ca), phosphorus (P) and albumin of 155 healthy infants. Information of sun exposure, sociodemographic aspects of mothers and clinical and nutritional characteristics of infants were obtained through interviews with responsible for infants. Serum concentrations of 25(OH)D greater than 20ng / ml were considered adequate, between 12 to 20ng / ml insufficient and <12ng/ml, deficient. Results: Ten infants (6.5%, 95% Confidence Interval 3.5-11.4) presented VD insufficiency and none presented DVD. Only one infant had an increase in PTH serum concentrations and 35.5% of infants had high AP but none presented DVD or VD insufficiency. No changes in serum P, Ca and albumin concentrations were detected. No associations were found between serum concentrations of 25 (OH) D and AP, Ca and albumin. There was an association between serum concentrations of 25(OH)D and PTH even after adjusting for sex, age and body mass index; an association between serum concentrations of 25(OH)D and P was observed only after adjustment for covariates. There were no associations between VD insufficiency, sun exposure and VD supplementation. Conclusions: A low prevalence of insufficient concentrations of 25 (OH)D was observed. No associations were found between serum concentrations of 25 (OH)D and PTH, FA, Ca, P and albumin. Likewise, no associations were found between serum concentrations of 25 (OH)D, sun exposure and VD supplementation.
77

Prostaglandin and Vitamin D - some model studies.

Wong, Henry She Lai. January 1970 (has links)
No description available.
78

D - Brane charge groups and fusion rings in Wess - Zumino - Witten models

Ridout, D. January 2005 (has links)
This thesis presents the computation and investigation of the charges and the corresponding charge groups for untwisted symmetry - preserving D - branes in a Wess - Zumino - Witten model over a compact, connected, simply - connected, simple Lie group. First, some general ideas from conformal field theory are reviewed and applied to Wess - Zumino - Witten models. Boundary conformal field theory is then introduced with the aim of deriving the Cardy constraint relating the consistent boundary conditions to fusion. This is used to justify certain dynamical processes for branes, called condensation, which lead to a conserved charge and constraints on the corresponding charge group ( following Fredenhagen and Schomerus ). These constraints are then used to determine the charge groups for untwisted symmetry - preserving branes over all compact, connected, simply - connected, simple Lie groups. Rigorous proofs are detailed for the Lie groups SU ( r + 1 ) and Sp ( 2r ) for all ranks r, and the relevance of these results to K - theory is discussed. These proofs rely on an explicit presentation of the corresponding fusion rings ( over Z ), which are also rigorously derived for the first time. This computation is followed by a careful treatment of the Wess - Zumino - Wittenmodel actions ; the point being that the consistent quantisation paradigm developed can also be applied to brane charges to determine the charge groups. The usual ( string - theoretic ) D - brane charges are introduced, and are proved to exactly reproduce the charges of Fredenhagen and Schomerus when certain quantisation effects are brought into play. This is followed by a detailed investigation of the constraints induced on the corresponding charge groups by insisting that the string - theoretic charges be well-defined. These constraints are demonstrated to imply those of Fredenhagen and Schomerus except when the Wess - Zumino - Witten model is over a symplectic Lie group, Sp ( 2r ). In the symplectic case, numerical computation shows that these constraints can be strictly stronger than those of Fredenhagen and Schomerus. A possible resolution is offered indicating why this need not contradict the K - theoretic interpretation. / Thesis (Ph.D.)--School of Chemistry and Physics, 2005.
79

Agrippa d'Aubigné's Histoire universelle : objectivity and partisanship /

Acquario, Thomas Joseph, January 1900 (has links)
Thesis--Ohio State University. / Bibliography: leaves 223-228. Available online via OhioLINK's ETD Center
80

D.H. Lawrence as revolutionary his quarrels with industrialization and World War I /

Melchione, Barbara A. January 1983 (has links)
Thesis (M.A.)--Kutztown University. / Source: Masters Abstracts International, Volume: 45-06, page: 2845. Typescript. Abstract precedes thesis as preliminary leaves [i]-iv. Includes bibliographical references (leaves 118-120).

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