904 resultados para Absorption of light
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A simple method for calculating the asymptotic D-state observables for light nuclei is suggested. The method exploits the dominant clusters of the light nuclei. The method is applied to calculate the He-4 asymptotic D to S normalization ratio rho(alpha) and the closely related D-state parameter D2alpha. The study predicts a correlation between D2alpha and B(alpha), and between rho(alpha) and B(alpha), where B(alpha) is the binding energy of He-4. The present study yields rho(alpha) congruent-to -0.14 and D2alpha congruent-to -0.12 fm2 consistent with the correct experimental eta(d) and the binding energies of the deuteron, triton, and the alpha particle, where eta(d) is the deuteron D-state to S-state normalization ratio.
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This in vitro study evaluated the cytotoxic effects of a restorative resin composite applied to an immortalized odontoblast-cell line (MDPC-23). Seventy-two round resin discs (2-mm thick and 4 mm in diameter) were light-cured for 20 or 40 seconds and rinsed, or not, with PBS and culture medium. The resin discs were divided into four experimental groups: Group 1: Z-100/20 seconds; Group 2: Z-100/20 seconds/rinsed; Group 3: Z100/40 seconds; Group 4: Z-100/40 seconds/rinsed. Circular filter paper was used as a control material (Group 5). The round resin discs and filter papers were placed in the bottom of wells of four 24-well dishes (18 wells for each experimental and control group). MDPC-23 cells (30,000 cells/cm(2)) were plated in the wells and allowed to incubate for 72 hours. The zone of inhibition around the resin discs was measured under inverted light microscopy; the MTT assay was carried out for mitochondrial respiration and cell morphology was measured under SEM. The scores obtained from inhibition zone and MTT assay were analyzed with the Kruskal-Wallis followed by Dunnett tests. In Groups 1, 2, 3 and 4, the thickness of the inhibition zone was 1,593 +/- 12.82 mum, 403 +/- 15.49 mum, 1,516 +/- 9.81 mum and 313 +/- 13.56 mum, respectively. There was statistically significant difference among the experimental and control groups at the 0.05 level of significance. The MTT assay demonstrated that the resin discs of the experimental groups 1, 2, 3 and 4 reduced the cell metabolism by 83%, 40.1%, 75.5% and 24.5%. Only between the Groups 2 and 4 was there no statistically significant difference for mitochondrial respiration. Close to the resin discs, the MDPC-23 cells exhibited rounded shapes, with only a few cellular processes keeping the cells attached to the substrate or, even disruption of plasma membrane. Adjacent to the inhibition zone, the cultured cells exhibited multiple fine cellular processes on the cytoplasmic membrane organized in epithelioid nodules, similar to the morphology observed to the control group. Based on the results, the authors may conclude that the Z-100 resin composite light cured for 20 seconds was more cytopathic to MDPC-23 cells than Z-100 light cured for 40 seconds. The cytotoxic effects of the resin discs decreased after rinsing them with PBS and culture medium. This was confirmed by MTT assay and upon evaluation of the inhibition zone, which was narrower following rinsing of the resin discs.
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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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We tested the effects of monochromatic light on the specific growth rate (SGR), feed intake and feed efficiency (FE) of juvenile pikeperch, Sander lucioperca (L.). Pikeperch were reared individually for 42 days in aquaria covered with blue, green, yellow or red gelatin filters or white paper (control; n=5). Linear regression analysis indicated a significant positive effect of longer wavelengths of light on the condition factor (CF), FE and SGR. The final weight, SGR and CF were significantly higher in fish reared under red than under white light, and FE was better under green, yellow and red light than under white light (Dunnett's post hoc test, P < 0.05) while blue was comparable to white light in terms of the measured parameters. After the growth trial, the spectral sensitivity of photoreceptor cells in the retina was tested using microspectrophotometry, which revealed the presence of rods with lambda(max) at ca. 530 nm and two cone classes, absorbing maximally at ca. 535 and 603 nm, all containing a porphyropsin-based pigment. These results suggest that the presence of mid and long wavelength-sensitive cones enhances visual sensitivity under mid-wavelength and long-wavelength environments, and thus supports the finding that longer wavelengths of incoming light can improve FE and SGR of the cultivated pikeperch.
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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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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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It is shown that three-body non-Borromean halo nuclei like 12Be, 18C, 20C, considered as neutron-neutron-core systems, have p-wave virtual states with energy of about 1.7 times the corresponding neutron-core binding energy. We use a renormalizable model that guarantees the general validity of our results in the context of short range interactions.
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The present assay had as objective evaluating spore germination of Blechnum brasiliense in relation to light, plant density and disinfection. The assay was carried out at Jaboticabal, Sào Paulo State, Brazil, from February, 22 to June, 30, 1996. The experimental design was randomized blocks on a factorial scheme (3x2x2), consisting of 12 treatments, three environments (shade-house, dark-house and germination camera), 2 densities (0.005 grs and 0.010 grs of spores/treatment) and presence or absence of disinfection. The leaf coverage area (130 days) and the number of days necessary to germinate were evaluated. The germination camera data were not analysed because they were insignificant; consequently, the remining data were analysed on a 2×2×2 scheme. The shade-house provided larger green covering area and a faster germination. The density of 0.0 lOg of spore/treatments presented the largest green covering area. The supply of partial light was necessary for good germination. The interaction between the environment and the density had significant effect on the green covering area.
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Nile tilapia Oreochromis niloticus fingerlings were fed with purified or practical diets, supplemented with 150 Ing Zn/kg, from different sources. Dry matter (DM), crude protein (CP), ether extract (EE), and gross energy (GE) apparent digestibility coefficients (ADC), as well as zinc, copper, calcium, and phosphorus apparent absorption coefficients (AAC) were determined by the addition of 0.1% chromic oxide to the diets. The supplemental zinc sources utilized were commercial grade zinc sulfate monohydrate (ZnSO 4), zinc oxide (ZnO) and a zinc amino acid complex (Zn-AA). Analytical grade zinc sulfate heptahydrate was also utilized as a standard reference zinc source. There was a significant difference between purified (74.9%) and practical (41.3%) zinc AAC for the ZnO supplemented diets (P < 0.05). The supplemental zinc sources presented similar AAC when purified diets were utilized. However, ZnSO 4 was the best supplemental zinc source when practical type diets were used. There were no significant differences between supplemental zinc AAC from ZnS0 4 (68.9%), and supplemental zinc AAC from Zn-AA (61.3%) in practical diets, but Zn-AA diet showed a statistically lower zinc AAC when compared with the standard zinc source diet (75.6%). The practical diet supplemented with ZnO had the worst supplemental zinc AAC (41.3%). Dietary copper (74.21%), calcium (70.9%), and phosphorus (71.9%) AAC of the practical diets supplemented with ZnO were statistically lower (P < 0.05) than the respective AAC of the practical ZnSO 4 supplemented diets (83.6%, 84.1%, 87.1%).The ADC of the practical ZnO supplemented diet for DM (76.3%), CP (88.6%), EE (82.4%), and GE (81.6%) were statiscally lower than the respective ADC of the ZnSO 4 practical diet (86.0, 92.7, 93.6, 89.6%, respectively) and those ADC of the Zn-AA practical diet (84.7, 92.7, 93.7, 88.2%, respectively) (P < 0.05). Hence, these results indicate that ZnSO 4 and Zn-AA have equivalent intestinal absorption as supplemental zinc sources for Nile tilapia juveniles and both are superior to ZnO. © Copyright by the World Aquaculture Society 2005.