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1.
An experimental study is made of the time decay of activity of the CO–NO reaction on a Pd/Al2O3 looking at the effect on reaction order and apparent activation energy. The optimum kinetics parameters fitting the steady state data at moderate pressures are determined. The time decay curves are analyzed through various catalyst deactivation models.  相似文献   
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Estolides are a group of FA polyesters resulting from ester bond formation between a hydroxyl or olefinic group of one FA and the terminal carboxyl group of a second FA. These products are commonly found in trace amounts, forming tetraglycerides in several oil seed plants, and have been produced by acid clay and enzymatic catalysis in vitro. In this study, natural estolides produced by a bacterial culture are presented for the first time. Pseudomonas sp. 42A2 produced (E)-10-hydroxy-8-octadecenoic acid and (E)-7,10-dihydroxy-8-octadecenoic acid when grown on oleic acid. It is suggested that these FA were polymerized in culture by a lipase produced by the bacterial strain, resulting in a mixture of estolides. These compounds amounted to 3.8 g/L after 72 h of incubation. LC-MS analysis indicated that the types of estolides formed were dimers (m/z 560–610), trimers (m/z 845–906), tetramers (m/z 1122–1202), pentamers (m/z 1328–1424), and hexamers (m/z 1554–1788), with a relative abundance of 27.5, 19.4, 15, 9.7, and 11%, respectively. This is the first report in which hexamers were detected in a bacterial culture.  相似文献   
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The purpose of this study was to characterize and compare the carcass characteristics, cholesterol concentration, fatty acid composition of intramuscular fat and subcutaneous fat, and meat quality of Criollo Argentino and Braford steers reared in an extensive system, without supplementation, and slaughtered at approximately 400 kg live weight. The Braford steers had greater (P < 0.05) carcass weight, yield, conformation score, marbling degree, fat thickness and fatness score than Criollo Argentino steers. The tissue composition of the 10th rib was: 68.1% vs. 63.6% muscle, 23.9% vs. 20.4% bone and 8.2% vs. 16.3% fat for the Criollo Argentino and Braford breeds, respectively. The meat of Longissimus muscle from Braford steers was lighter, redder, yellower and more tender than that from Criollo Argentino steers. The meat of Longissimus muscle from Braford steers had a higher fat content, similar protein and ash contents and a lower (P ? 0.001) cholesterol concentration than that from Criollo Argentino steers.  相似文献   
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The influence of the Rh loading on the surface properties and catalytic behaviour of Rh/γ-Al2O3 catalysts has been studied. The series of catalysts presents differences in metal dispersion, reducibility, surface composition and catalytic activity. All the data reported suggest that the differences in catalytic behaviour in the methylcyclohexane dehydrogenation reaction can be explained in terms of electron-deficient rhodium clusters, essentially when the metal particle size becomes smaller than 15 Å.  相似文献   
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The Piracicaba, Capivari, and Jundiaí River Basins (RB-PCJ) are mainly located in the State of São Paulo, Brazil. Using a dynamics systems simulation model (WRM-PCJ) to assess water resources sustainability, five 50-year simulations were run. WRM-PCJ was developed as a tool to aid decision and policy makers on the RB-PCJ Watershed Committee. The model has 254 variables. The model was calibrated and validated using available information from the 80s. Falkenmark Water Stress Index went from 1,403 m3 person???1 year???1 in 2004 to 734 m3 P???1 year???1 in 2054, and Xu Sustainability Index from 0.44 to 0.20. In 2004, the Keller River Basin Development Phase was Conservation, and by 2054 was Augmentation. The three criteria used to evaluate water resources showed that the watershed is at crucial water resources management turning point. The WRM-PCJ performed well, and it proved to be an excellent tool for decision and policy makers at RB-PCJ.  相似文献   
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OBJECTIVE: To examine the effects of vitamin E on total serum protein glycation (fructosamine), hemoglobin glycation (HbA1c), and serum levels of glucose, total cholesterol, triglycerides, LDL-C, HDL-C, apolipoprotein A1 and apolipoprotein B. MATERIAL AND METHODS: Sixty poorly controlled diabetic patients were randomly assigned to receive either 1200 mg/day of vitamin E or identical placebo capsules during a two month period following a double blind cross-over design with a four week wash-out period between regimens. RESULTS: Seven patients were excluded from the study because of reasons not related to the medication. In the remaining 53 patients, the levels of serum glucose, fructosamine, HbA1c, total cholesterol, HDL-C, LDL-C, Apo A1 and Apo B did not vary significantly with vitamin E as compared with placebo. CONCLUSIONS: No significant effects of vitamin E on any of the parameters evaluated were observed in poorly controlled diabetic patients.  相似文献   
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Heparan sulfate is a highly sulfated carbohydrate polymer that binds to and modulates the activities of numerous proteins. The formation of these protein-binding domains in heparan sulfate is dependent on a series of biosynthetic reactions that modify the polysaccharide backbone; the initiating and rate-limiting steps of this process are the N-deacetylation and N-sulfation of N-acetylglucosamine residues in the polymer. We now report that in the rat liver, biosynthesis of heparan sulfate utilizes a single protein that possesses both N-deacetylase and N-sulfotransferase activities. This was accomplished by demonstrating that both activities resided in a purified soluble fusion protein containing the Golgi-lumenal portion of the enzyme. We propose that this protein be renamed the rat liver Golgi heparan sulfate N-deacetylase/N-sulfotransferase.  相似文献   
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Fluorescence immunoassays are popular for achieving high sensitivity, but they display limitations in biological samples due to strong absorption of light, background fluorescence from matrix components, or light scattering by the biomacromolecules. A powerful strategy to overcome these problems is introduced here by using fluorescent magnetic nanobeads doped with two boron‐dipyrromethane dyes displaying intense emission in the visible and near‐infrared regions, respectively. Careful matching of the emission and absorption features of the dopants leads to a virtual Stokes shift larger than 150 nm achieved by an intraparticle Förster resonance energy transfer (FRET) process between the donor and the acceptor dyes. Additionally, the magnetic properties of the fluorescent beads allow preconcentration of the sample. To illustrate the usefulness of this approach to increase the sensitivity of fluorescence immunoassays, the novel nanoparticles are employed as labels for quantification of the widely used Tacrolimus (FK506) immunosuppressive drug. The FRET‐based competitive inhibition immunoassay yields a limit of detection (LOD) of 0.08 ng mL?1, with a dynamic range (DR) of 0.15–2.0 ng mL?1, compared to a LOD of 2.7 ng mL?1 and a DR between 4.1 and 130 ng mL?1 for the immunoassay carried out with direct excitation of the acceptor dye.  相似文献   
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