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It was shown that adrenergic drugs, which increase the intracellular levels of cAMP, inhibit the rosette formation by T-lymphocytes, but stimulate the rosettes produced by B-lymphocytes. Cholinergic drugs, which increase the levels of cGMP, on the contrary, stimulate the formation of rosettes by T-lymphocytes but inhibit those produced by B-lymphocytes.  相似文献   
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The purpose of this article is to analyze systemically the Brazilian production chain of semiconductors. The specific objectives of this article are to represent the chain systemically and to identify key variables and leverage points that can increase the overall performance of the semiconductor industry. The research method is qualitative modelling. Eleven practitioners of the industry answered a questionnaire approaching various aspects of the semiconductor industry in Brazil. By a systemic approach, the complex behavior present in the industry was considered. By content analysis, we identified patterns in the speech of the respondents. Texts fragments allowed the identification of key themes and variables present in the system. The association among key variables and complex behavior helped to build a systemic structure, aimed at representing the main relationships in the system. From the systemic structure, eight leverage points were identified and discussed. The key implications of the findings are the damage that cheap imports make in the local market; the need of strong public policies that include more than tax reduction, but also local conditions, like clusters or technological parks, for the high-tech manufacture; and the promotion of conditions that stimulate private investment in the industry.  相似文献   
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Transmissible spongiform encephalopathies (TSEs) are neurodegenerative diseases associated with progressive oligo- and multimerization of the prion protein (PrPC), its conformational conversion, aggregation and precipitation. We recently proposed that PrPC serves as a cell surface scaffold protein for a variety of signaling modules, the effects of which translate into wide-range functional consequences. Here we review evidence for allosteric functions of PrPC, which constitute a common property of scaffold proteins. The available data suggest that allosteric effects among PrPC and its partners are involved in the assembly of multi-component signaling modules at the cell surface, impose upon both physiological and pathological conformational responses of PrPC, and that allosteric dysfunction of PrPC has the potential to entail progressive signal corruption. These properties may be germane both to physiological roles of PrPC, as well as to the pathogenesis of the TSEs and other degenerative/non-communicable diseases.  相似文献   
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Antennation can play several roles in hymenopteran copulation, mainly in wasps. The digger wasp Sphex ingens Smith has a very peculiar sexual behaviour, in which forced copulation is a striking element. However, communication through antennation during the pre-copulation and copulation phases and the relationship between the sexual performance of males and the final result of copulation require further clarification. The sexual behaviour of wild populations of S. ingens was filmed during the breeding season in a site between the beaches Meros and Aventureiro, Ilha Grande, southeastern Brazil. We assessed antennation behaviour, courtship duration, sexual performance, and genital clasping. Only successful males had the genital clasping assessed. Evidence found so far points out that the successful males showed better sexual performance – that is, they antennated more in a shorter courtship duration. Also, genital clasping in successful males did not depend on antennation, courtship duration, or sexual performance. Our results shed light on some aspects of the sexual behaviour of wasps, as they explain part of the sexual selection mechanisms adopted by the species.  相似文献   
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Polydora websteri belongs to a group of the Spionidae known as the Polydora complex, members of which are known for building tubes within the shells of mussels and for their ability to infest commercially valuable bivalves, which causes serious losses for malacoculture. P. websteri is a species subjected to increasing research due to the global scale at which these infestations occur. In this paper, we describe the larval development of P.cf. websteri associated with the oyster Crassostrea cf. brasiliana in a tropical region of north-east Brazil. The main structures of all stages of development were analysed and compared to other populations of P. websteri. Ovigerous capsules of P.cf. websteri were cultured in the laboratory and the larval stages were analysed until metamorphosis. Ovigerous capsules were present in all sampling intervals, indicating that this population exhibits continuous reproduction. Up to 21 capsules per tube were found, and the number of eggs per capsule varied from 20 to 40. All observed eggs developed into larvae. Larval development from egg to recruitment stage did not exceed 13 days. Metamorphosis occurred when larvae attained 17 chaetigers, at which stage important diagnostic characteristics were revealed, such as the spines on chaetiger 5. The developmental stages of P.cf. websteri larvae, and the morphological features found at each stage, are in accordance with what has been recorded for temperate populations. In our study, the planktonic stage was found to be of shorter duration than elsewhere, which might be associated with the higher temperatures at which larvae were cultured compared to previous studies.  相似文献   
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Bronchial asthma is a common inflammatory disease caused by the interaction of genetic and environmental factors. Through a genome-wide association study and a replication study consisting of a total of 7,171 individuals with adult asthma (cases) and 27,912 controls in the Japanese population, we identified five loci associated with susceptibility to adult asthma. In addition to the major histocompatibility complex and TSLP-WDR36 loci previously reported, we identified three additional loci: a USP38-GAB1 locus on chromosome 4q31 (combined P = 1.87 × 10(-12)), a locus on chromosome 10p14 (P = 1.79 × 10(-15)) and a gene-rich region on chromosome 12q13 (P = 2.33 × 10(-13)). We observed the most significant association with adult asthma at rs404860 in the major histocompatiblity complex region (P = 4.07 × 10(-23)), which is close to rs2070600, a SNP previously reported for association with FEV(1)/FVC in genome-wide association studies for lung function. Our findings offer a better understanding of the genetic contribution to asthma susceptibility.  相似文献   
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