998 resultados para Vigas celulares


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Breast cancer has received an increasing attention because it is one of the most common cancer type and a leading cause of morbity and mortality among women worldwide. This disease has been considered as a heterogeneous condition, demonstrating a large spectrum of clinical and histopathological variability. In the last two decades, several studies have been conducted to identify new molecular markers of cancer cells, including the alterations of DNA methylation, which is the major epigenetic mechanism associated with the control of gene expression. The hypermethylation of promoter-associated CpG islands contributes to the loss of function of several cancer-related genes, including those encoding to the estrogen receptor (ESR) and progesterone receptor (PGR). This study aimed to determine the methylation patterns of CpG islands of the genes encoding the estrogen receptor α (ESR1 gene, promoters A and B), estrogen receptor β (ESR2 gene) and progesterone receptor (PGR gene, promoter A and B) in 15 cell lines derived from breast cancer. The DNA methylation analysis was based on the “Methylation Specific-Polymerase Chain Reaction” (MSP), which provides a qualitative assessment of the methylation status of a specific CpG island. The results revealed heterogeneous data: the promoter region of ESR1A showed complete methylation in one cell line (BT549) and only two cell lines showed partial methylation (MDA-MB-231 and MDA-MB-453), while the others lineages presented unmethylated alleles. The promoter region of isoform ESR1B was unmethylated in the cell lines BT549, SKBR3 and T47D; partial methylation were observed in the cell lines MDA-MB- 231, MCF-7 and ZR-75-30, while the others cell lines presented complete methylation. All lineages showed complete or partial methylation of the ESR2 gene. The methylation pattern of the promoter A of the PGR ...(Complete abstract click electronic access below)

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Os carrapatos são ectoparasitas hematófagos que apresentam grande importância econômica e médico-veterinária por transmitirem patógenos para os diversos hospedeiros, bem como por causarem redução na qualidade da carne, couro e leite devido à sua ação espoliativa. A espécie Rhipicephalus sanguineus (Ixodidae), conhecida popularmente como “carrapato do cão” tem ampla distribuição geográfica e é a principal responsável pela transmissão de patógenos aos cães domésticos, além de ser potencial transmissora destes para a espécie humana. A espécie Ornithodoros rostratus (Argasidae) conhecida como “carrapato do chão” é encontrada principalmente na região centro-oeste do Brasil e tem causado problemas, tais como grandes hematomas na pele do hospedeiro, principalmente dos suínos e dos animais silvestres, além de humanos, devido a sua fixação. O tecido fluído desses animais é a hemolinfa, a qual é composta por plasma linfático e por diversos tipos de células, ainda pouco estudadas. A hemolinfa é responsável pelo transporte de diversas substâncias importantes para a sobrevivência do animal, tais como enzimas, hormônios e resíduos a serem excretados pelo organismo. O objetivo deste trabalho foi o de realizar uma descrição comparativa e detalhada das células encontradas na hemolinfa das duas espécies de carrapatos citadas

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Brazil is a major world producer and exporter of agricultural products like soybeans, sugar, coffee, orange and tobacoo. However, the action of phytopathogenic fungi has been one of the largest challenges encountered in the field as they are responsible for approximately 25 to 50 per cent of losses in crops of fruits and vegetables. The presence of these pathogens is always a problem, because the damage on the tissues and organs promote lesions which decreses growth vegetation and often leads the individual (host) to death. Therefore, it is crucial to understand the process of spreading of these pathogens in the field to develop strategies which prevent the epidemics caused by them. In this study, the dispersal of fungi phytopathogenic in the field was modeled using the automata cellular formalism. The growth rate of infected plants population was measured by the radius of gyration and the influence of host different susceptibility degrees into the disease spread was assessed. The spatial anisotropy related to the plant-to-plant space and the system’s response to distinct seasonal patterns were also evaluated. The results obtained by a mean field model (spatially implicit models) emphasized the importance of the spatial structure on the spreading process, and dispersal patterns obtained by simulation (using a cellular automata) were in agreement with thse observed in data. All computational implementation was held in language Cl

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A síntese de hipusina é uma modificação pós-traducional única e essencial que ocorre somente no provável fator de início de tradução de eucariotos 5A (eIF5A). Enquanto que a enzima desoxi-hipusina sintase catalisa a formação de desoxi-hipusina no precursor de eIF5A, posterior hidroxilação deste intermediário pela enzima desoxi-hipusina hidroxilase gera a forma madura hipusinada. Apesar da essencialidade de eIF5A e hipusina no crescimento celular, a função biológica desempenhada por este fator intrigante permaneceu obscura por décadas. Recentemente, novas evidências fortaleceram o envolvimento de eIF5A na tradução, mas o seu mecanismo de ação ainda precisa ser elucidado. Com o objetivo de identificar proteínas que interagem com eIF5A que pudessem contribuir para a elucidação de sua função, foi realizado um rastreamento de duplo-híbrido através do qual um novo parceiro físico foi revelado, a proteína codificada pelo gene YJR070C, denominado LIA1 (Ligante de eIF5A) pelo nosso laboratório. Entretanto, este dado não contribuiu para a determinação do papel de eIF5A dentro da célula, pois a função exercida por Lia1 era naquele momento desconhecida. Em 2006, a clonagem de LIA1 como o gene codificador da enzima desoxi-hipusina hidroxilase culminou na completa identificação das enzimas da via de síntese de hipusina no precursor de eIF5A. No entanto, o mecanismo pelo qual eIF5A contendo desoxi-hipusina é hidroxilado não é completamente conhecido. Como o rastreamento por duplo-híbrido tem-se revelado de grande importância para a compreensão dos processos biológicos que ocorrem em uma célula, pois vem sendo amplamente empregado na elucidação da função de diferentes fatores celulares através da análise de interações proteína-proteína, o presente trabalho visou à busca de ligantes físicos de Lia1 através do emprego desta técnica... (Resumo completo, clicar acesso eletrônico abaixo)

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In this paper, a computational analysis, using a cellular automata model, has been developed to analyze post-feeding dispersal behavior of blow y larvae. This model aimed to: simulate the exponential decline of pupal number in relation to the feed source and spatial oscillation due to larval interaction during dispersal; study whether the prior pupal presence in uences distribution patterns of larval frequency; and compare obtained unidirectional dispersal patterns to the cross-dimensional ones. The cellular automata (CA) model was able to successfully reproduce the essential features of the larval dispersal process and, thus, show the importance of local interaction in the studied dispersal process dynamics. Oscillations could be explained by the interaction among dispersing larvae and intrinsic pupation time. The box size and the initial larval density were important factors for the experiment because they in uenced the results. Results showed that the unidirectional dispersal could be used to simulate the larval dispersion that occurs in the natural environment, because both models had a similar result. These results are important to understand how di erent factors can in uence the dynamics of blow y larval dispersal, bringing important results for behavioral ecology and forensic entomology

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In civil engineering, a structure is the whole sustainment of a construction and, thus, it is important that it remains intact throughout its lifetime. An engineering construction must last for decades without losing its functionality. However its purpose may be altered and several times the original structure does not meet the new needs of use. Still, in new buildings, the functionality is altered due to possible flaws in execution and the structure, invariably does not reach the desired solicitation needs. In cases like this, the commonly adopted solutions are, basically, the demolishment followed by the reconstruction of the desired mold or the structural reinforcement. This second option, for long years, has not been put to practice due to certain factors such as the high costs for its implantation, use of inadequate reinforcement execution techniques, and the culture of people involved in the area regarding its use and, in this case, the option would always be the reconstruction. Thoughtout the years, some techniques were developed to allow the execution of structural reinforcements with low costs and in efficient ways. An interesting, fast, efficient and economical technique is the structural reinforcement through metal sheets put together with epoxy resin that can be applied in beams, slabs and pillars. In the present work the different behavior of beams reinforced with this technique. Steel is a very recommended material for these reinforcements due to its characteristics related to traction, compression and the effectiveness of the technique related to its cost. For the attachment the epoxy resin is recommended, since it allows the joining of two materials, in this case, steel and concrete. The efficiency of this union is so considerably high that it rarely produces any flaws in adherence and, normally, when it happens it is due to problems in the execution process, not in the union of materials

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Experimental models composed by human and animal cell lines are simplified and informative, allowing them to be widely used for biomedical research. Most laboratories that use in vitro cultivated cells maintain a variation of cell lines stored and cultivated. Therefore, misidentification and cross-contamination events can happen during cell lines handling. This problem can generate a repertoire of dubious results and papers, which may prejudice biomedical research. Recently it was created the International Cell Line Authentication Committee (ICLAC), which aims to spread knowledge about cross-contamination and misidentification of in vitro cell lines. Despite of the efforts spent trying to aware scientific community about the importance of the correct identification of cells, the number of papers based on misidentified cell lines it´s still worrying, compromising the reliability of out coming results and conclusions regarding them. The present study aims to analyze and discuss the main advantages and limitations of eukaryote in vitro cell lines use, characterizing the cell lines authentication problems. Therefore, compilation and critical analyses of literature data was realized, aiming to improve the understanding about this subject. Based on information about 445 cell lines with issues published by ICLAC it´s clear that contamination in human cell lines represented 89,2 % of mentioned problems. HeLa cell line was the responsible for most contamination, especially in 92 normal tissue cell lines, representing 44,6% of the contamination. These results reinforce the importance of periodic maintenance of cell lines cultures by labs and implementation of authentication methods as polymorphic STRs, besides obtaining cell lines from reliable sources and cell banks

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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The objective of the present work was to evaluate Pinus’ glued laminated timber (glulam) beams and steel reinforced glulam beams, using PU mono-component adhesive in lamination step and epoxy adhesive to bond steel bars. The mechanical performance was verified through bending test, and the adopted method based on homogenized section, to considerate the differences between wood and steel mechanical properties. The homogenization section method proved itself effective in obtaining the stiffness of the parts in MLCA. The stiffness of reinforced beams increased 91% in comparison with glulam beams, differing only 5.5 % from value of stiffness calculated

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Os carrapatos são considerados um dos mais importantes grupos dentre os artrópodes, por serem vetores de agentes patogênicos, que podem atacar animais, bem como o próprio homem. Dentre as diversas espécies de carrapato destaca-se a do Rhipicephalus sanguineus, pertencente à família Ixodidae e com ampla distribuição em todos os continentes. Atualmente esta espécie é considerada uma praga urbana, de grande importância médico-veterinária, que parasita principalmente o cão doméstico. Os ovários de carrapatos são considerados órgãos vitais para o sucesso biológico deste grupo de animais. Neste sentido, desenvolver pesquisas para se conhecer a ação de produtos naturais com reconhecida ação repelente ou acaricida, sobre o sistema reprodutor feminino de carrapatos, traria importantes informações para um melhor entendimento dos efeitos da ação destes produtos nos ovócitos desses ectoparasitas, contribuindo principalmente para o desenvolvimento de métodos de controle alternativos menos tóxicos para os organismos não-alvo e menos poluentes para o meio ambiente. Dessa forma, o presente estudo analisou as alterações morfofisiológicas causadas por diferentes concentrações do óleo de andiroba no ovário de fêmeas semiingurgitadas de carrapatos R. sanguineus

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Pós-graduação em Engenharia Mecânica - FEB

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Pós-graduação em Engenharia Civil - FEIS

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Osseointegration involves a cascade of biological events, which can be accelerated by modifying the micro and/or nanometric topography of dental implant surfaces. Considering that different treatment types modify the titanium surface giving it a more pronounced rough topography, and physicochemical changes that appear to positively influence the osseointegration process, a literature review was made on the main types of surface treatments and their influence on the biological and cellular aspects of osseointegration, with publications dating from 1969 until the present moment. Although the precise role of the implant surface on the osseointegration of dental implants is not completely clear, the specific effects of implant surface on bone regeneration, initial kinetics, and evolution of mechanical properties have shown to be quite promising. Thus, based on dental implant surface modifications, osseointegration can be defined as a process by which rigid asymptomatic fixation of an alloplastic material can be achieved and kept in close contact with bone tissue, being resistant to early and late functional loads. This process can be modulated by an appropriate treatment of the alloplastic material surface.

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The aim of this research study was to evaluate the structural behaviour of the wood and concrete composite system for bridge decks with emphasis on the metal shear connectors. Experimental tests were performed on composite specimens and wood and concrete beams with a metallic connector system in an X position, using CS100900-type screws. All specimens and beams were submitted to static loads until failure in order to obtain the strength and stiffness of the connection system. The experimental results for the stiffness of the beams were compared with the analytical results obtained through the Mohler model, presenting good equivalence for service loads. The experimental results obtained demonstrate that the most significant damage in composite systems occurred in the connectors' areas.