987 resultados para Covalent cross-link
Resumo:
Nephrolithiasis is one of the most common diseases in the Western world. The disease manifests itself with intensive pain, sporadic infections, and, sometimes, renal failure. The symptoms are due to the appearance of urinary stones (calculi) which are formed mainly by calcium salts. These calcium salts precipitate in the renal papillae and/or within the collecting ducts. Inherited forms of nephrolithiasis related to chromosome X (X-linked hypercalciuric nephrolithiasis or XLN) have been recently described. Hypercalciuria, nephrocalcinosis, and male predominance are the major characteristics of these diseases. The gene responsible for the XLN forms of kidney stones was cloned and characterized as a chloride channel called ClC-5. The ClC-5 chloride channel belongs to a superfamily of voltage-gated chloride channels, whose physiological roles are not completely understood. The objective of the present review is to identify recent advances in the molecular pathology of nephrolithiasis, with emphasis on XLN. We also try to establish a link between a chloride channel like ClC-5, hypercalciuria, failure in urine acidification and protein endocytosis, which could explain the symptoms exhibited by XLN patients.
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Development of suitable membranes is a fundamental requisite for tissue and biomedical engineering applications. This work presents fish gelatin random and aligned electrospun membranes cross-linked with glutaraldehyde (GA). It was observed that the fiber average diameter and the morphology is not influenced by the GA exposure time and presents fibers with an average diameter around 250 nm. Moreover, when the gelatin mats are immersed in a phosphate buffered saline solution (PBS), they can retain as much as 12 times its initial weight of solution almost instantaneously, but the material microstructure of the fiber mats changes from the characteristic fibrous to an almost spherical porous structure. Cross-linked gelatin electrospun fiber mats and films showed a water vapor permeability of 1.37 ± 0.02 and 0.13 ± 0.10 (g.mm)/(m2.h.kPa), respectively. Finally, the processing technique and cross-linking process does not inhibit MC-3T3-E1 cell adhesion. Preliminary cell culture results showed good cell adhesion and proliferation in the cross-linked random and aligned gelatin fiber mats.
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Thermal degradation of as electrospun chitosan membranes and samples subsequently treated with ethanol and cross-linked with glutaraldehyde (GA) have been studied by thermogravimetry (TG) coupled with an infrared spectrometer (FTIR). The influence of the electrospinning process and cross-linking in the electrospun chitosan thermal stability was evaluated. Up to three degradation steps were observed in the TG data, corresponding to water dehydration reaction at temperatures below 100 ºC, loss of side groups formed between the amine groups of chitosan and trifluoroacetic acid between 150 – 270 ºC and chitosan thermal degradation that starts around 250 ºC and goes up to 400 ºC. The Kissinger model was employed to evaluate the activation energies of the electrospun membranes during isothermal experiments and revealed that thermal degradation activation energy increases for the samples processed by electrospinning and subsequent neutralization and cross-linking treatments with respect to the neat chitosan powder.
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Tourism is a phenomenon that moves millions of people around the world, taking as a major driver of the global economy. Such relevance is reflected in the proliferation of studies in the overall area known as tourism, under various perspectives and backgrounds. In the light of such multitude of insights our study aims at gaining a deeper understanding of customer profiling and behavior in cross-border tourism destinations. Previous studies conducted in such contexts suggest that cross-border regions (CBRs) are an attractive and desirable idea, yet requiring further theoretical and empirical research. The new configuration of many CBRs calls for a debate on issues concerning its development, raising up important dimensions, such as, organization and planning of common tourism destinations. There is still a gap in the understanding of destination management in CBRs and the customer profile and motivations. Overall this research aims at attaining a deeper understanding of the profile and behavior of consumers in tourism settings, addressing the predisposition for the destination. The study addresses the following research question: “What factors influence customer behavior and attitudes in a CBRs tourism destination?” To address our question we will take an interdisciplinary perspective bringing together inputs from marketing, tourism and local economics. When addressing consumer behavior in tourism previous studies considered the following constructs: involvement, place attachment, satisfaction and destination loyalty. In order to establish the causal relationships in our theoretical model, we intend to develop a predominant quantitative design, yet we plan to conduct exploratory interviews. In the analysis and discussion of results, we intend to use Structural Equation Modeling. It will further allow understanding how the constructs in the research model relate to each other in the specified context. Results are also expected to have managerial implications. Consequently our results may assist decision makers in developing their local policies.
Resumo:
Tourism is a phenomenon that moves millions of people around the world, taking as a major driver of the global economy. Such relevance is reflected in the proliferation of studies in the overall area known as tourism, under various perspectives and backgrounds. In the light of such multitude of insights our study aims at gaining a deeper understanding of customer profiling and behavior in cross-border tourism destinations. Previous studies conducted in such contexts suggest that cross-border regions (CBRs) are an attractive and desirable idea, yet requiring further theoretical and empirical research. The new configuration of many CBRs calls for a debate on issues concerning its development, raising up important dimensions, such as, organization and planning of common tourism destinations. There is still a gap in the understanding of destination management in CBRs and the customer profile and motivations. Overall this research aims at attaining a deeper understanding of the profile and behavior of consumers in tourism settings, addressing the predisposition for the destination. The study addresses the following research question: “What factors influence customer behavior and attitudes in a CBRs tourism destination?” To address our question we will take an interdisciplinary perspective bringing together inputs from marketing, tourism and local economics. When addressing consumer behavior in tourism previous studies considered the following constructs: involvement, place attachment, satisfaction and destination loyalty. In order to establish the causal relationships in our theoretical model, we intend to develop a predominant quantitative design, yet we plan to conduct exploratory interviews. In the analysis and discussion of results, we intend to use Structural Equation Modeling. It will further allow understanding how the constructs in the research model relate to each other in the specified context. Results are also expected to have managerial implications. Consequently our results may assist decision makers in developing their local policies.
Resumo:
This study aims at gaining a deeper understanding of customer profiling and behaviour in cross-border tourism destinations. The study is developed under a niche marketing perspective. It is our view that niche marketing is not confined to the limits of national markets. Previous studies suggest that cross-border regions are an attractive notion, yet they require further theoretical and empirical research. There is still a gap in the understanding of destination management in cross-border regions and the customer profile and motivations. Overall this research attempts to produce a deeper understanding of the profile and behaviour of consumers in tourism settings, addressing the predisposition for the destination in specific contexts (cross-border tourism regions).
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Este artigo tem suas raízes em algumas questões relacionadas à "forma" e ao "conteúdo" do que nós, professores, ensinamos na área de Administração da Produção e Operações. Inicialmente, descrevo a evolução histórica desse campo no Brasil. Em seguida, discuto a crise de identidade que o campo está sofrendo. Com o objetivo de apresentar respostas para essa situação, apresento seis propostas para o desenvolvimento e consolidação do campo. Finalmente, descrevo uma iniciativa prática, envolvendo uma disciplina específica da área, ensinada para alunos de pós-graduação. Essa iniciativa enfatiza a "dimensão do conteúdo" (de uma abordagem técnico-operacional para uma abordagem estratégico-gerencial) como também a "dimensão da forma" (do foco no ensino para o foco no aprendizado). O sucesso dessa experiência em curso confirma a coerência da agenda proposta e induz futuros aperfeiçoamentos.
Resumo:
Multi-national enterprises often attempt to replicate successful management practices in "foreign" environments. However, such practices may be ethnocentric because they fit the assumptions, behaviors, expectations, and values of the home cultural environment. Unless the underlying assumptions are shared, transfer to a differing environment may fail. Even if the focus is shifted from cultural differences to implementation, implementation approaches may also be criticized as ethnocentric for the same reasons. In this article, a non-ethnocentric model is expanded and used to test the portability of one management practice, performance appraisal, from the USA to Brazil. This "Test of Portability" may help managers understand which management practices are portable, and, perhaps even more valuable, provide a rationale for adaptation or rejection.
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Este artigo tem como objetivo investigar se as aquisições realizadas por empresas brasileiras fora do País nos últimos 15 anos têm aumentado o desempenho financeiro dessas empresas. Além disso, é realizada uma análise empírica dos fatores determinantes desse sucesso, com base nas teorias institucional, sociocultural e de aprendizagem organizacional. Os resultados indicam que, de fato, as investidas cross border de companhias do Brasil melhoram o desempenho, que é positivamente impactado quando a distância cultural entre os países da adquirida e da adquirente é baixa ou média e quando o ambiente institucional no qual a empresa-alvo se encontra é desenvolvido. Já a relação entre as experiências anteriores das brasileiras em fusões ou aquisições internacionais e o desempenho de uma nova aquisição fora do País segue o formato de U invertido, enfatizando a relevância de se considerar a experiência com fusões e aquisições da empresa compradora além das características institucionais dos seus países-alvo.
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ABSTRACTBank failures affect owners, employees, and customers, possibly causing large-scale economic distress. Thus, banks must evaluate operational risks and develop early warning systems. This study investigates bank failures in the Organization for Economic Co-operation and Development, the North America Free Trade Area (NAFTA), the Association of Southeast Asian Nations, the European Union, newly industrialized countries, the G20, and the G8. We use financial ratios to analyze and explore the appropriateness of prediction models. Results show that capital ratios, interest income compared to interest expenses, non-interest income compared to non-interest expenses, return on equity, and provisions for loan losses have significantly negative correlations with bank failure. However, loan ratios, non-performing loans, and fixed assets all have significantly positive correlations with bank failure. In addition, the accuracy of the logistic model for banks from NAFTA countries provides the best prediction accuracy regarding bank failure.
Resumo:
Given the heterogeneity of effect sizes within the population for any treatment, identifying moderators of outcomes is critical [1]. In weight management programs, there is a high individual variability in terms of weight loss and an overall modest success [2]. Some people will adopt and sustain attitudes and behaviors associated with weight loss, while others won’t [3]. To predict weight loss outcome just from the subject’s baseline information would be very valuable [4,5]. It would allow to: - Better match between treatments and individuals - Identify the participants with less probability of success (or potential dropouts) in a given treatment and direct them to alternative therapies - Target limited resources to those most likely to succeed - Increase cost-effectiveness and improve success rates of the programs Few studies have been dedicated to describe baseline predictors of treatment success. The Healthy Weight for Life (USA) study is one of the few. Its findings are now being cross-validated in Portuguese samples. This paper describes these cross-cultural comparisons.
Resumo:
Avaliar a força de preensão é fundamental pela sua relação com a capacidade funcional dos indivíduos, permitindo determinar níveis de risco para incapacidade futura e assim estabelecer estratégias de prevenção. Grande parte dos estudos utiliza o dinamómetro hidráulico JAMAR que fornece o valor da força isométrica obtida durante a execução do movimento de preensão palmar. Contudo, existem outros dinamómetros disponíveis, como é o caso do dinamómetro portátil computorizado E-Link (Biometrics), que fornece o valor da força máxima (peak force), mas também outras variáveis relacionadas, como por exemplo a taxa de fadiga. Não existem, contudo, estudos de análise de concordância que nos permitam aceitar e comparar ou não os valores obtidos com os dois equipamentos e porventura utilizá-los indistintamente.
Resumo:
INTRODUCTION: In spite of general agreement that cross-cultural research is needed in the health area, most existing investigations of children's development of health and illness-related concepts have involved samples from developed countries. The study examined the development of the concepts of health and illness as a function of subject's age, socio-economic status (SES), gender and grade level in a Brazilian sample of 96 elementary and junior high school students. METHODS: Subjects were interviewed individually and their ideas of health and illness were assessed through open-ended questions. Participants' answers were transcribed verbatim and subjected to content analysis. RESULTS: Chi-square analyses revealed significant age, school grade and SES-related differences in participants' concepts of health and illness. DISCUSSION AND CONCLUSION: The themes employed by subjects to define both health and illness were broadly consistent with those found by previous research. The study showed a predictable relationship between subject's age and school grade level and increasingly more highly differentiated and multidimensional concepts of health and illness. This investigation suggests that, for the most part, cross-cultural similarities in children's concepts of health and illness may be more striking than the differences.
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This paper analyzes the risk-return trade-off in European equities considering both temporal and cross-sectional dimensions. In our analysis, we introduce not only the market portfolio but also 15 industry portfolios comprising the entire market. Several bivariate GARCH models are estimated to obtain the covariance matrix between excess market returns and the industrial portfolios and the existence of a risk-return trade-off is analyzed through a cross-sectional approach using the information in all portfolios. It is obtained evidence for a positive and significant risk-return trade-off in the European market. This conclusion is robust for different GARCH specifications and is even more evident after controlling for the main financial crisis during the sample period.
Resumo:
Introdução – Avaliar a força de preensão mostrou ser de primordial importância pela sua relação com a capacidade funcional dos indivíduos, permitindo determinar níveis de risco para incapacidade futura e, assim, estabelecer estratégias de prevenção. Grande parte dos estudos utiliza o dinamómetro hidráulico JAMAR que fornece o valor da força isométrica obtida durante a execução do movimento de preensão palmar. Contudo, existem outros dinamómetros disponíveis, como é o caso do dinamómetro portátil computorizado E‑Link (Biometrics) que fornece o valor da força máxima (peak force), para além de outras variáveis, como a taxa de fadiga. Não existem, contudo, estudos que nos permitam aceitar e comparar ou não os valores obtidos com os dois equipamentos e porventura utilizá‑los indistintamente. Objetivos – Avaliar a concordância entre as medições da força de preensão (força máxima ou peak force em Kg) obtida a partir de dois equipamentos diferentes (dinamómetros portáteis): um computorizado (E‑Link, Biometrics) e outro hidráulico (JAMAR). Metodologia – Foram avaliados 29 indivíduos (13H; 16M; 22±7 anos; 23,2±3,3 kg/m2) em 2 dias consecutivos, na mesma altura do dia. A posição de teste escolhida foi a recomendada pela Associação Americana de Terapeutas Ocupacionais e foi escolhido o melhor resultado de entre 3 tentativas para a mão dominante. Realizou‑se uma análise correlacional entre os valores obtidos na variável analisada em cada equipamento (coeficiente de Spearman) e uma análise de Bland & Altman para verificar a concordância entre as duas medições. Resultados – O coeficiente de correlação entre as duas medições foi elevado (rS= 0,956; p<0,001) e, pela análise de Bland & Altman, os valores obtidos encontram‑se todos dentro do intervalo da média±2SD. Conclusões – As duas medições mostraram ser concordantes, revelando que os dinamómetros testados podem ser comparáveis ou utilizados indistintamente em diferentes estudos e populações. ABSTRACT: Introduction – Assess grip strength has proved to be of vital importance because of its relationship with functional capacity of individuals, in order to determine levels of risk for future disability and thereby establish prevention strategies. Most studies use the JAMAR Hydraulic dynamometer that provides the value of isometric force obtained during the performance of grip movement. However, there are other dynamometers available, such as portable computerized dynamometer E‑Link (Biometrics), which provides the value of maximum force (peak force) in addition to other variables as the rate of fatigue. There are no studies that allow us to accept or not and compare values obtained with both devices and perhaps use them interchangeably. Purpose – To evaluate the agreement between the measurements of grip strength (peak force or maximum force in kg) obtained from two different devices (portable dynamometers): a computerized (E‑Link, Biometrics) and a hydraulic (JAMAR). Methodology – 29 subjects (13H, 16M, 22 ± 7 years, 23.2 ± 3.3 kg/m2) were assessed on two consecutive days at the same time of day. The test position chosen was recommended by the American Association of Occupational Therapists and was considered the best result from three attempts for the dominant hand. A correlation was studied between values obtained in the variable analyzed in each equipment (Spearman coefficient) and Bland‑Altman analysis to assess the agreement between the two measurements. Results – The correlation coefficient between the two measurements was high (rs = 0,956, p <0,001) and Bland & Altman analysis of the values obtained are all within the range of mean±2SD. Conclusions – The two measurements were shown to be concordant, revealing that the tested dynamometers can be comparable or used interchangeably in different studies and populations.