998 resultados para 25-248
Resumo:
Altas concentrações plasmáticas de leptina têm sido relacionadas ao aumento da formação de espécies reativas de oxigênio (ROS) que podem desempenhar um papel regulador central em eventos inflamatórios e cardiovasculares. Estudos recentes têm demonstrado que a vitamina D é capaz de reduzir marcadores do estresse oxidativo, bem como modular a produção de citocinas inflamatórias. O objetivo do presente estudo foi avaliar o efeito do pré-tratamento com concentração fisiológica (10-10 M) e suprafisiológica(10-7 M) de 1,25(OH)2D3 na produção do ânion superóxido (O2) e nos fatores de transcrição NF-κB e Nrf2,em células endoteliais humanas estimuladas com diferentes concentrações de leptina (1 e 10 ng/mL). Quando as células foram pré-tratadas com 1,25(OH)2D3, e estimuladas com leptina (1 e 10 ng/mL), a 1,25(OH)2D3 reduziu (p<0,05) a produção de ânion superóxido (O ), principalmente na concentração de 10-7 M. O fator de transcrição NF-κB foi positivamente ativado em células incubadas com 10 ng/mL de leptina, entretanto, quando se realizou o pré-tratamento com 1,25(OH)2D3 houve redução da translocação do NF-κB, assim como a produção de citocinas reguladas por este fator de transcrição. Também foi observado que o pré-tratamento com 10-7 M de 1,25(OH)2D3 aumentou de forma significativa (p<0,05) a expressão do fator de transcrição Nrf2 na fração nuclear em comparação ao controle, principalmente quando associada à 10 ng/mL de leptina (p<0,05). Tomados em conjunto, nossos resultados indicam que o tratamento com ambas as concentrações, 10-10 e 10-7 M de 1,25(OH)2D3 em células endoteliais humanas, foram eficazes em inibir a produção do ânion superóxido (O2), citocinas pró-inflamatórias, bem como inibir a translocação nuclear do fator de transcrição NF-κB, e ativar a via antioxidante Nrf2. Estes achados sugerem que o pré-tratamento com ambas as concentrações (fisiológica e suprafisiológica) de 1,25(OH)2D3 na presença de alta concentração de leptina, pode ter um efeito positivo no endotélio através da regulação de marcadores de inflamação e atividade antioxidante
Resumo:
The Adaptive Collaborative Management of Fisheries Training workshop was held in Sekondi, Western Region of Ghana as part of the project “Integrated Coastal and Fisheries Governance Initiative” locally referred to as “H n Mpoano”. The aim of the project is to support the government of Ghana achieve its development objective of poverty reduction, food security, sustainable fisheries management and biodiversity conservation and contributes to its vision: Ghana’s coastal and marine ecosystems are sustainably managed to provide goods and services that generate long-term socioeconomic benefit to communities while sustaining biodiversity.
Resumo:
In this paper we report the development of 1.4 kV 25 A PT and NPT Trench IGBTs with ultra-low on-resistance, latch-up free operation and highly superior overall performance when compared to previously reported DMOS IGBTs in the same class. We have fabricated both PT and transparent anode NPT devices to cover a wide range of applications which require very low on-state losses or very fast time with ultra-low switching losses. The minimum forward voltage drop at the standard current density of 100A/cm2 was 1.1 V for PT non-irradiated devices and 2.1 V for 16 MRad PT irradiated devices. The non-irradiated transparent emitter NPT structure has a typical forward voltage drop of 2.2 V, a turn-off time below 100 ns and turn-off energy losses of 11.2 mW/cm2 at 125 C. The maximum controllable current density was in excess of 1000A/cm2.
Resumo:
Teeth of 71 estuarine dolphins (Sotalia guianensis) incidentally caught on the coast of Paraná State, southern Brazil, were used to estimate age. The oldest male and female dolphins were 29 and 30 years, respectively. The mean distance from the neonatal line to the end of the first growth layer group (GLG) was 622.4 ±19.1 μm (n=48). One or two accessory layers were observed between the neonatal line and the end of the first GLG. One of the accessory layers, which was not always present, was located at a mean of 248.9 ±32.6 μm (n=25) from the neonatal line, and its interpretation remains uncertain.The other layer, located at a mean of 419.6 ±44.6 μm (n=54) from the neonatal line, was always present and was first observed between 6.7 and 10.3 months of age. This accessory layer could be a record of weaning in this dolphin. Although no differences in age estimates were observed between teeth sectioned in the anterior-posterior and buccal-lingual planes, we recommend sectioning the teeth in the buccal-lingual plane in order to obtain on-center sections more easily. We also recommend not using teeth from the most anterior part of the mandibles for age estimation. The number of GLGs counted in those teeth was 50% less than the number of GLGs counted in the teeth from the median part of the mandible of the same animal. Although no significant difference (P>0.05) was found between the total lengths of adult male and female estuarine dolphins, we observed that males exhibited a second growth spurt around five years of age. This growth spurt would require that separate growth curves be calculated for the sexes. The asymptotic length (TL∞), k, and t0 obtained by the von Bertalanffy growth model were 177.3 cm, 0.66, and –1.23, respectively, for females and 159.6 cm, 2.02, and –0.38, respectively, for males up to five years, and 186.4 cm, 0.53 and –1.40, respectively, for males older than five years. The total weight (TW)/total length (TL) equations obtained for male and female estuarine dolphins were TW = 3.156 × 10−6 × TL 3.2836 (r=0.96), and TW = 8.974 × 10−5 × TL 2.6182 (r=0.95), respectively.
Resumo:
Selectivity studies using cod end and cover to determine the optimum cod end mesh size for commercial size groups of shrimps was carried out at Cochin during 1963-64 fishing season. The normality of the result was checked by trouser cod end method. Although the present investigation was mainly aimed to find out suitable cod end mesh size for commercial varieties of shrimps, five commonly occurring species of fishes were also taken. The 50% escape level, co-efficient of selectivity and selection factor for all the species were worked out. From the findings, the authors stress the necessity of increasing the cod end mesh size from the present condition (25.4 to 31.70 mm) to 41.65 mm fabricated mesh size to avoid depletion of the natural population.
Resumo:
The primary objective in doing this work was to become acquainted with as many forms as possible of the marine fauna of the intertidal zone and if possible to determine some of the environmental relationships which exist in as many different types of habitats as possible. Due to limited amount of time spent in this study no very intensive work could be done and only a general survey was made of the more conspicuous forms of life which were encountered. Most of the work consisted of collecting and observing animals in the tide pools during periods of low tides. The animals collected were then taken to the laboratory and observed and determined as to species. Notes were taken as to place, time, and situation under which the animals were found. As many different types of habitats as possible were visited which included rocky intertidal areas of Mussel Point, Point Pinos, Lighthouse Point, Pescadero Point and Carmel Point just east of Carmel Beach. Sandy beaches were visited at Monterey Beach, Carmel Beach and Asilomar Beach. A marine estuary habitat was visited at Elkhorn Slough. More than two hundred species were identified and observed during this six-week period. A rather hasty population study was made of the eelgrass, Phyllospadix, of the intertidal zone at Mussel Point and of an algae, Gigartina caniculata, which grows at the level just above the eelgrass.
Resumo:
A complete comparative chromosome map of the white-browed gibbon (Hylobates hoolock, 2n = 38), white-cheeked gibbon (Hylobates leucogenys, 2n = 52), and human has been established by hybridising H. leucogenys chromosome-specific paints and human 24-colour paints onto H. hoolock metaphase chromosomes. In the 18 H. hoolock autosomes, we identified 62 conserved segments that showed DNA homology to regions of the 25 H. leucogenys autosomes, Numerous interchromosomal rearrangements differentiate the karyotypes of H. leucogenys and H. hoolock. Only H. hoolock chromosome 10 showed homology to one entire autosome of H. leucogenys. The hybridisation of human 24-colour paints not only confirmed most of the chromosome correspondences between human and H. hoolock established previously but also helped to correct five erroneous assignments and revealed three new segments. Our results demonstrate that the karyotypes of the extant gibbons have arisen mainly through extensive translocation events and that the karyotype of H. hoolock more closely resembles the ancestral karyotype of Hylobates, rather than the karyotype of H. leucogenys. Copyright (C) 2001 S. Karger AG, Basel.