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1.
D. I. T. Fávaro D. Mafra V. A. Maihara L. Cuppari M. B. A. Vasconcellos S. M. F. Cozzolino 《Journal of Radioanalytical and Nuclear Chemistry》2004,259(3):533-536
Having in mind the importance of Fe and Zn content in the diets of nondialyzed patients with chronic renal failure, diets
of 39 patients with ages varying from 18 to 79 years under a conservative treatment were analyzed by INAA. The 24-hour recall
method was used for sample collection. The content of proximate composition was also determined. The average daily dietary
intake was compared to the new recommended values by the Food and Nutrition Board. It was observed that the diets were deficient
for these elements and, therefore, there should be a nutritional follow-up to avoid possible negative effects.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
2.
The United States Geological Survey reference sample AGV-1 andesite, and three alkaline rocks from the apatite mine of Jacupiranga, Brasil, were analyzed by thermal neutron activation analysis using destructive and non-destructive methods, and high resolution Ge(Li) gamma-ray detectors. One of the rocks, a carbonatite, was also analyzed by instrumental activation analysis with epithermal neutrons. A greater number of elements can be determined using the radiochemical separation, but the precision and accuracy attained by INAA and RNAA were of the same order for most of the elements analyzed. Epithermal activation was more advantageous for tantalum, terbium and holmium. Comparison of the analytical results for USGS reference sample (AGV-1) with the data published by others gave good agreement. Statistical tests used for comparison of the results of destructive and non-destructive methods, as well as other results are presented. 相似文献
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Jane Luiza Nogueira Fernandes Rodrigo Octavio Mendonça Alves de Souza Rodrigo Bagueira de Vasconcellos Azeredo 《Magnetic resonance in chemistry : MRC》2012,50(6):424-428
In the present investigation, we studied the enzymatic synthesis of monoacylglycerols (MAG) and diacylglycerols (DAG) via the esterification of saturated fatty acids (stearic, palmitic and an industrial residue containing 87% palmitic acid) and glycerol in a solvent‐free system. Three immobilized lipases (Lipozyme RM IM, Lipozyme TL IM and Novozym 435) and different reaction conditions were evaluated. Under the optimal reaction conditions, esterifications catalyzed by Lipozyme RM IM resulted in a mixture of MAG and DAG at high conversion rates for all of the substrates. In addition, except for the reaction of industrial residue at atmospheric pressure, all of these products met the World Health Organization and European Union directives for acylglycerol mixtures for use in food applications. The products were quantified by 13C NMR, with the aid of an external reference signal which was generated from a sealed coaxial tube filled with acetonitrile‐d3. After calibrating the area of this signal using the classical external reference method, the same coaxial tube was used repeatedly to quantify the reaction products. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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E. C. C. Vasconcellos F. R. Petersen K. M. Evenson 《International Journal of Infrared and Millimeter Waves》1981,2(4):705-711
We report for the first time wavelength, relative polarization, and frequency measurements for 47 new cw FIR laser lines in the wavelength region from 120 to 1714 m, all obtained by optically pumping CD2F2 with a CO2 laser. Relative output powers were also measured. For comparison, the 189.8 m line pumped by RI(34) is nearly five times as efficient as the 118.8 m methyl alcohol line.Contribution of the U.S. Government, not subject to copyright. 相似文献
8.
E. C. C. Vasconcellos A. Scalabrin F. R. Petersen K. M. Evenson 《International Journal of Infrared and Millimeter Waves》1981,2(3):533-539
Twenty-four new submillimeter laser lines in fully deuterated methyl alcohol (CD3OD) in the wavelength range from 52 to 328 m have been obtained in a Fabry-Perot FIR resonator by optically pumping the methanol with a cw CO2 laser. We have made accurate wavelength measurements and have determined the relative polarization of most of the known CD3OD laser lines. The frequencies of 13 of the strongest lines were also measured.Contribution of the U.S. Government, not subject to copyright. 相似文献
9.
E. C. C. Vasconcellos S. C. Zerbetto L.-H. Xu R. M. Lees L. R. Zink K. M. Evenson 《International Journal of Infrared and Millimeter Waves》1998,19(5):719-726
Eight far-infrared laser lines have been obtained by optically pumping acetaldehyde (CH3CHO) and nine by pumping vinyl fluoride (CH2CHF) with a cw CO2 laser. The far-infrared laser structure used a metal-dielectric waveguide cavity. This is the first reported observation of four of the laser lines in acetaldehyde. In this work, we measure the frequency, optimum pressure of operation, relative intensity, relative polarization, and pump offset from CO2 laser-line center. 相似文献
10.
M. J. A. Armelin M. B. A. Vasconcellos E. B. Pereira F. Sircilli Neto 《Journal of Radioanalytical and Nuclear Chemistry》1989,132(2):261-267
A radiochemical neutron activation analysis procedure is described for the determination of concentration levels of iridium in sedimentary rocks and in the geochemical standard PCC-1. After irradiation, the powdered rock samples and standard are dissolved with a mixture of HF, HNO3 and HClO4 in a teflon bomb. The final solution obtained, in dilute HCl, is passed through a column containing the cationic resin Bio Rad AG 50W-X8. The interfening radionuclides are sorbed by the resin. The effluent solution containing iridium is concentrated for counting by evaporation. Experiments with radioactive tracer for checking radiochemical separation yield are carried out. The accuracy of the method is evaluated by means of analysis of the USGS “standard rock” peridotite, PCC-1. The precision is about 25% in the ppb range. The method is used for the determination of iridium in 16 samples of sedimentary rocks collected at different depths in the “Campos” basin-RJ (BRAZIL). 相似文献