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51.
J. D. T. Arruda-Neto A. C. Cestari C. B. Zamboni M. Saiki G. P. Nogueira L. E. C. Fonseca M. V. Manso-Guevara A. Deppman V. P. Likhachev J. Mesa O. A. M. Helene S. A. C. Jorge M. N. Martins A. N. Gouveia O. Rodriguez F. Guzmán F. Garcia 《Journal of Radioanalytical and Nuclear Chemistry》2005,263(2):287-289
Summary Neutron activation analysis has been used to study uranium incorporation in poultry bones as function of chow doped with: (a) uranium (20 ppm); (b) U-doped food (20 ppm) plus phytase (120 ppm) and (c) U-doped food (20 ppm) plus phytase (180 ppm). To investigate this situation experiments involving several groups of Cobb broilers was performed. Two animals per group were sacrificed weekly up to their adultness and uranium concentration in the tibia was measured. It was observed that the concentration of uranium (µg U/g bone) is decreasing all along the animal life spanning period of 14-42 days. This behavior suggests that the skeleton mass is growing faster than the corresponding accumulation of uranium. The administration of phytase seems not to alter this scenario. 相似文献
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Eduardo J. Nassar Evelisy C. de O. Nassor Lilian R. Ávila Paula F. S. Pereira Alexandre Cestari Luiz M. Luz Katia J. Ciuffi Paulo S. Calefi 《Journal of Sol-Gel Science and Technology》2007,42(1):21-26
Organic–inorganic hybrid materials have been used as fillers to reinforce dental resin composites, which require strengthening
to improve their performance in large stress-bearing applications such as crowns and multiple-unit restorations. Homogeneous
organic–inorganic hybrid materials with high performance were prepared by mixing 3-methacryloxypropyltrimethoxysilane (MPTS)
and tetraethylorthosilicate (TEOS) synthesized by the sol–gel route. The matrix was prepared by hydrolyzing and condensing
the TEOS and MPTS, using basic catalysis and excess water. The resulting xerogel was treated at 50, 100, 150, and 200 °C for
4 h, and the structure was analyzed by thermogravimetry (TG/DTA), photoluminescence (PL), nuclear magnetic resonance (NMR
29Si and 13C), transmission electron microscopy (TEM), infrared spectroscopy (IR), and Raman spectroscopy. The PL spectra displayed the
Eu3+ lines characteristic of 5D0 → 7FJ (J = 0, 1, 2, 3, 4) ions, and the blue emission was ascribed to the silica matrix. TG, MNR and infrared spectroscopy analyses indicated the hybrid
silica was stable, with the organic part present up to 150 °C. Increasing the temperature of the heat treatment was found
to increase the degree of hydrolysis. The size and morphology of the silica particles were identified by TEM. 相似文献
53.
Interaction of indigo carmine dye with chitosan evaluated by adsorption and thermochemical data 总被引:3,自引:0,他引:3
Chitosan can use its protonated amine groups to adsorb strongly anionic species from diluted solutions. In this work, adsorption and thermochemical data on the interaction of the dye indigo carmine with chitosan in aqueous medium were found, in order to obtain new adsorption data on this relatively unexplored chitosan field. The studies were carried out by the batch method from 35 to 50 degrees C. The adsorption results were well fitted to both Langmuir and Freundlich adsorption models. The increase in the temperature decreased the adsorption of the dye. The enthalpy of interaction, when a monolayer of the dye was formed on the chitosan surface, delta(int)H, of -23.2 kJ mol(-1) was encountered for all temperature ranges studied. The spontaneity of the interaction is indicated by the delta(int)G values from -9.1 to -8.2 kJ mol(-1). Other thermodynamic quantities were also calculated and are discussed. 相似文献
54.
Natlia Cestari Moreno Camila Carrio Machado Garcia Clarissa Ribeiro Reily Rocha Veridiana Munford Carlos Frederico Martins Menck 《Photochemistry and photobiology》2019,95(1):345-354
The crucial role of DNA polymerase eta in protecting against sunlight‐induced tumors is evidenced in Xeroderma Pigmentosum Variant (XP‐V) patients, who carry mutations in this protein and present increased frequency of skin cancer. XP‐V cellular phenotypes may be aggravated if proteins of DNA damage response (DDR) pathway are blocked, as widely demonstrated by experiments with UVC light and caffeine. However, little is known about the participation of DDR in XP‐V cells exposed to UVA light, the wavelengths patients are mostly exposed. Here, we demonstrate the participation of ATR kinase in protecting XP‐V cells after receiving low UVA doses using a specific inhibitor, with a remarkable increase in sensitivity and γH2AX signaling. Corroborating ATR participation in UVA‐DDR, a significant increase in Chk1 protein phosphorylation, as well as S‐phase cell cycle arrest, is also observed. Moreover, the participation of oxidative stress is supported by the antioxidant action of N‐acetylcysteine (NAC), which significantly protects XP‐V cells from UVA light, even in the presence of the ATR inhibitor. These findings indicate that the ATR/Chk1 pathway is activated to control UVA‐induced oxidatively generated DNA damage and emphasizes the role of ATR kinase as a mediator of genomic stability in pol eta defective cells. 相似文献
55.
A 2(4-1) fractional factorial design is employed to study Cu(II) desorption on organofunctionalized silicas. Two types of silicas, at amounts of 100 and 200 mg and two acidic levels, and contact times were employed. Our study indicates that the effects of HCl and contact time on the percentage number of moles of copper are 13.23 and 18.53, respectively. However, the binary interaction of these factors is very small. Three important antagonistic and synergistic binary effects involving the silica type, acidic quantity, and contact time factors are found. The silica mass showed an insignificant principal effect. The desorption data are compared with those previously published concerning adsorption processes on both functionalized silicas. Copyright 2000 Academic Press. 相似文献
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