312 resultados para Rompimento de barreira
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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In a general way, in an electric power utility the current transformers (CT) are used to measurement and protection of transmission lines (TL) 1 The Power Line Carriers systems (PLC) are used for communication between electrical substations and transmission line protection. However, with the increasing use of optical fiber to communication (due mainly to its high data transmission rate and low signal-noise relation) this application loses potentiality. Therefore, other functions must be defined to equipments that are still in using, one of them is detecting faults (short-circuits) and transmission lines insulator strings damages 2. The purpose of this paper is to verify the possibility of using the path to the ground offered by the CTs instead of capacitive couplings / capacitive potential transformers to detect damaged insulators, since the current transformers are always present in all transmission lines (TL's) bays. To this a comparison between this new proposal and the PLC previous proposed system 2 is shown, evaluating the economical and technical points of view. ©2010 IEEE.
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Despite the fact that the processes of embryo development and implantation of mammals do not occur in atmospheric tension in vivo, it is common practice in laboratories for in vitro fertilization (IVF) the culture of embryos in an oxygen tension of 20%. The discrepancy between the tensions of oxygen leads to important discussions about their effects in vitro embryo development. It is believed that the culture of embryo in atmospheric oxygen tension can be detrimental to the quality of the data for predisposing them to the negative interference of reactive oxygen species (ROS), resulting in oxidative stress, leading to deleterious effects on metabolism embryo gene expression and blastocysts grown in those conditions. Faced with arguments for and against the culture of embryos in vitro oxygen tensions similar to those found in vivo, this revies article aims to condense and discuss the literature concerning the influence of oxygen tension on the quality of in vitro culture.
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Background: Neuromyelitis optica (NMO) is considered relatively more common in non-Whites, whereas multiple sclerosis (MS) presents a high prevalence rate, particularly in Whites from Western countries populations. However, no study has used ancestry informative markers (AIMs) to estimate the genetic ancestry contribution to NMO patients. Methods: Twelve AIMs were selected based on the large allele frequency differences among European, African, and Amerindian populations, in order to investigate the genetic contribution of each ancestral group in 236 patients with MS and NMO, diagnosed using the McDonald and Wingerchuck criteria, respectively. All 128 MS patients were recruited at the Faculty of Medicine of Ribeirão Preto (MS-RP), Southeastern Brazil, as well as 108 healthy bone marrow donors considered as healthy controls. A total of 108 NMO patients were recruited from five Neurology centers from different Brazilian regions, including Ribeirão Preto (NMO-RP). Principal Findings: European ancestry contribution was higher in MS-RP than in NMO-RP (78.5% vs. 68.7%) patients. In contrast, African ancestry estimates were higher in NMO-RP than in MS-RP (20.5% vs. 12.5%) patients. Moreover, principal component analyses showed that groups of NMO patients from different Brazilian regions were clustered close to the European ancestral population. Conclusions: Our findings demonstrate that European genetic contribution predominates in NMO and MS patients from Brazil. © 2013 Brum et al.
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Recent reports on the prevalence of multiple sclerosis (MS) have described discrepancies between the rates in cities in the northeastern and southeastern regions of Brazil, representing a north-south gradient. European immigrants settled in southeastern and southern Brazil at the beginning of the twentieth century. In this study, we report the frequency of European ancestors among Brazilian MS patients in four cities in the southern and southeastern regions of Brazil. Methods: A total of 652 consecutive patients with confirmed MS diagnoses seen at four centers in Belo Horizonte, Ribeirão Preto, Londrina and Santos were asked about the origin of their ancestors, going back three generations. Results: 287 (44%) reported Italian ancestry, 211 (32%) reported that all ancestors were born in Brazil, 49 (7.5%) had Portuguese ancestry and 70 (10%) had Spanish ancestry. The patients in Belo Horizonte and Londrina reported higher proportions of Italian ancestry than the proportions estimated for the populations of their respective States. Conclusion: Brazil has a north-south gradient of 0.91/100,000 per degree of latitude, which is higher than the gradient for Latin America. Since the largest immigrant group that settled in southern and southeastern Brazil was from Italy, it is possible that Italian immigration was one of the factors that have contributed toward increasing the prevalence of MS in these regions. © 2013 Elsevier B.V. All rights reserved.
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The lectin Artin M has been shown to accelerate the wound-healing process. The aims of this study were to evaluate the effects of Artin M on wound healing in the palatal mucosa of rats and to investigate the effects of Artin M on transforming growth factor beta (TGF-β) and vascular endothelial growth factor (VEGF) secretion by rat gingival fibroblasts. A surgical wound was created on the palatal mucosa of 72 rats divided into three groups according to treatment: C - Control (nontreated), A - Artin M gel, and V - Vehicle. Eight animals per group were sacrificed at 3, 5, and 7 days postsurgery for histology, immunohistochemistry and determination of the levels of cytokines, and growth factors. Gingival fibroblasts were incubated with 2.5 μg/mL of Artin M for 24, 48, and 72 hours. The expression of VEGF and TGF-β was determined by enzyme-linked immunosorbent assay. Histologically, at day 7, the Artin M group showed earlier reepithelialization, milder inflammatory infiltration, and increased collagen fiber formation, resulting in faster maturation of granular tissue than in the other groups (p < 0.05). Artin M-induced cell proliferation in vivo and promoted a greater expression of TGF-β and VEGF in both experiments (p < 0.05). Artin M was effective in healing oral mucosa wounds in rats and was associated with increased TGF-β and VEGF release, cell proliferation, reepithelialization, and collagen deposition and arrangement of fibers. © 2013 by the Wound Healing Society.
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Risk factors for development of multiple sclerosis (MS) are still a matter of debate. Latitude gradient, vitamin D deficiency and season of birth are among the most investigated environmental factors associated with the disease. Several international studies suggest that birth in spring is a substantial risk factor for MS. We investigated the season of birth as a potential risk for MS in different geographical regions of Brazil. We conducted a cross-sectional retrospective study with 2257 clinically definite MS patients enrolled in 13 Brazilian MS clinics in the south, southeast, and northeast regions of Brazil. Demographic and clinical data relating to date of birth and clinical features of the disease were collected and analysed, and subsequently compared with birth date among the general Brazilian population. The distribution of date of birth of MS patients showed an increase in spring and a decrease in autumn, with no difference being observed in the other seasons. In conclusion, season of birth is a probable risk factor for MS in most parts of Brazil. These findings may be related to the role that vitamin D plays in MS pathogenesis. © 2013 Elsevier B.V. All rights reserved.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Pós-graduação em Estudos Linguísticos - IBILCE
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Pós-graduação em Artes - IA
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Pós-graduação em Engenharia Elétrica - FEB