851 resultados para Block random copolymers


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Sixty-three Paracoccidioides brasiliensis isolates obtained from three nine-banded armadillos (Dasypus novem-cinctus), one Amazonian armadillo's and 19 clinical isolates were compared by random amplified polymorphic DNA analysis with the primer OPG-19. The isolates were divided into three major clusters, I, II and III. Coincidences between human and armadillo isolates were observed in clusters I and II. Cluster III consisted only of armadillos' isolates. The results suggested that (I) humans may acquire P. brasiliensis infection by contact with armadillo's environment, (II) there may be P. brasiliensis genotypes peculiar to the animal, and (III) individual armadillos may be infected with P brasiliensis cells with different genotypes.

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Agaricus blazei (Ab) has become popularly known for its medicinal properties. Scientifically, it has been tested with regard to its capacity to protect genetic material against damage. We examined different organic extracts (methanolic extract-ME, hexanic extract-HE and n-butanolic extract-BE) and an aqueous extract (AE) of Ab, for their capacity to induce DNA damage as well as for their protective effect. Genetic damage was determined by the chromosomal aberration assay (CA) in CHO-k1 cells for all extracts and the cytokinesis block micronucleus assay (CBMN) in non drug-metabolizing (CHO-k1) and drug-metabolizing (HTC) cell lines for extract BE only. The extracts did not show clastogenicity but showed anticlastogenicity. The greatest percent reduction obtained were with BE (105%) and AE (126%) treatments in CA. BE treatment did not display genotoxicity in CHO-k1, but was genotoxic in HTC. However, BE was shown to be antigenotoxic causing decreased micronucleus frequency in HTC and CHO-k1 cells. These results suggest that all the extracts contained protective substances, but in some cases they could show a genotoxic effect with regard to metabolism. Therefore, these findings warrant caution in the use of this mushroom by the population. (c) 2005 Elsevier Ltd. All rights reserved.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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This study aimed at evaluating performance and egg quality of Japanese quails fed feeds containing different corn and limestone particle sizes. A total number of 648 birds in the peak of production was distributed in a random complete block experimental design, using a 2x3 factorial arrangement (2 corn particle sizes and 3 limestone particle sizes). Birds were designated to one of two blocks, with six replicates of 18 birds each. Mean geometric diameter (MGD) values used were 0.617mm and 0.723mm (corn fine and coarse particle sizes, respectively), and 0.361mm, 0.721mm, and 0.947mm (limestone fine, intermediate and coarse particle sizes, respectively). The following treatments were applied: T1: fine corn feed, with 100% fine limestone; T2: fine corn feed, with 50% fine limestone and 50% intermediate limestone; T3: fine corn feed, with 50% fine limestone and 50% coarse limestone; T4: coarse corn feed, with 100% fine limestone; T5: coarse corn feed, with 50% fine limestone and 50% intermediate limestone; T6: coarse corn feed, with 50% fine limestone and 50% coarse limestone. The experiment lasted 112 days, consisting of 4 cycles of 28 days. No significant interaction was observed among corn and limestone particle sizes for any of the analyzed parameters. There were no significant effects (p>0.05) of the tested corn particle sizes on quail performance or egg quality. There were significant (p<0.05) isolated effects of limestone particle size only on the percentage of cracked eggs, which was reduced when birds fed 50% coarse limestone (0.947mm) and 50% fine limestone (0.361mm) as compared to those fed 100% fine limestone. Therefore, the inclusion of 50% coarse limestone (0.947mm) is recommended for quail egg production.

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Objetivou-se neste estudo avaliar as características nutricionais e a digestibilidade in vitro de silagens de diferentes cultivares de milho colhidas em duas alturas de corte. Foram avaliadas 11 cultivares (Dina 766, Dina 657, Dina 1000, P 3021, P 3041, C 805, C 333, AG 5011, FO 01, Dina co 9621 e BR 205) colhidas 5 cm acima do solo (baixa) e 5 cm abaixo da inserção da primeira espiga (alta). O experimento foi delineado em blocos casualizados (três blocos), arranjados em esquema fatorial 11 × 2. As silagens das plantas colhidas na altura de corte alta apresentaram teor médio de matéria seca significativamente superior às silagens das plantas colhidas na altura de corte baixa. As cultivares FO 01, AG 5011, Dina co 9621 e Dina 766 apresentaram maior teor de proteína bruta, que as cultivares C 805, P 3041 e P 3021, as quais apresentaram os menores teores deste nutriente. A elevação da altura de corte aumentou os coeficientes de digestibilidade verdadeira in vitro da matéria seca e digestibilidade in vitro da matéria seca das silagens avaliadas. O aumento da altura de corte melhorou o valor nutritivo das silagens, diminuindo as concentrações das frações fibrosas e aumentando a digestibilidade in vitro da matéria seca.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Purpose: The aim of this study was to evaluate quantitatively and qualitatively the influence of estrogen deficiency on autogenous bone block grafts in aged variectomized rats. Materials and Methods: Fifty 12-month-old female Wistar rats were used in the study. They were divided into 2 groups, an ovariectomized group and a sham-operated group. After 30 days the animals received autogenous block bone grafts on the angle of the mandible, harvested from the calvaria. The animals were euthanized at 7, 14, or 28 days postoperatively. Results: Histologic analysis showed that at 7 days postsurgery, the interface between graft and recipient site in the sham-operated group appeared filled by a granulation tissue with angiogenic activity, whereas the ovariectomized group still exhibited a blood clot and a granulation tissue in organization. on the 14th postoperative day, the interface in the shamoperated group was partially filled by newly formed bone establishing a union between the graft and the recipient site. The interface in the ovariectomized group was typically filled by granulation tissue with discrete osteogenic activity in most specimens. on the 28th postoperative day, the graft in the sham-operated group appeared histologically integrated to the mandible. However, the interface in the ovariectomized group appeared partially filled by newly formed bone, with areas of interposed connective tissue. The statistical analysis revealed that bone neoformation was significantly greater in the sham-operated group (57.41% at 14 days and 68.35 at 28 days) in comparison with the ovariectomized group (40.82% at 14 days and 53.09 at 28 days) at the 5% level. Conclusion: The estrogen depletion caused by the ovariectomy hindered the healing process of autogenous block bone grafts placed in the mandibles of aged rats.

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This study investigated the effects of 670 nm laser, at different fluences, on the viability of skin flap in rats. One hundred male animals were used. The animals were divided into control group; group treated with 3 J/cm(2); group treated with 6 J/cm(2); group treated with 12 J/cm(2) and group treated with 24 J/cm(2). The skin flap was made on the backs of all animals studied, with a plastic sheet interposed between the flap and the donor site. Laser irradiation was done immediately after the surgery and on days 1, 2, 3 and 4 after surgery. The percentage of necrosis of the flap was calculated at the 7th postoperative day. Additionally, a sample of each flap was collected to enable us to count the blood vessels. Treated animals showed a statistically significant smaller area of necrosis than did the control group. The necrosis in the treated groups was 41.82% (group 2), 36.51% (group 3), 29.45% (group 4) and 20.37% (group 5). We also demonstrated that laser irradiation at 670 nm, at all doses used, had a stimulatory effect on angiogenesis. Our study showed that the 670 nm laser was efficient to increase the viability of the skin flap, at all fluences used, with a tendency of reaching better results at higher doses.

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

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Two Brazilian populations of Psammolestes tertius (Ceara and Minas Gerais) collected from thornbird nests (Furnariidae) were compared by male genital morphology, morphametry, isoenzymes, and random amplified polymorphic DNA (RAPD). Merle genitalia showed no difference between the populations. In contrast, morphometry, isoenzyme, and RAPD clearly distinguished the two populations. Possible mechanisms of dispersal and the origin of Psammolestes are discussed.

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The patterns of genetic variation of samples of Candida spp. isolated from patients infected with human immunodeficiency virus in Vitória, state of Espírito Santo, Brazil, were examined. Thirty-seven strains were isolated from different anatomical sites obtained from different infection episodes of 11 patients infected with the human immunodeficiency virus (HIV). These samples were subjected to randomly amplified polymorphic DNA (RAPD) analysis using 9 different primers. Reproducible and complex DNA banding patterns were obtained. The experiments indicated evidence of dynamic process of yeast colonization in HIV-infected patients, and also that certain primers are efficient in the identification of species of the Candida genus. Thus, we conclude that RAPD analysis may be useful in providing genotypic characters for Candida species typing in epidemiological investigations, and also for the rapid identification of pathogenic fungi.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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