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41.
Watson is a fully developed suburb of some 30 years in Canberra (the capital city of Australia). A plunge dip using arsenical pesticides for tick control was operated there between 1946 and 1960. Chemical investigations revealed that many soil samples obtained from the study area contained levels of arsenic exceeding the current health-based investigation levels of 100 mg kg-1 set by the National Healthy and Medical Research Council in Australia. For the speciation study, nine composite samples of surface and sub-surface soils and a composite samples of rocks were selected. ICP-MS analysis showed that arsenic levels in these samples ranged from 32 to 1597 mg kg-1. Chemical speciation of arsenic showed that the arsenite (trivalent) components were 0.32-56% in the soil and 44.8% in the rock composite samples. Using a rat model, the absolute bioavailability of these contaminated soils relative to As3+ or As5+ ranged from 1.02 to 9.87% and 0.26 to 2.98%, respectively. An attempt was made to develop a suitable leachate test as an index of bioavailability. However, the results indicated that there was no significant correlation between the bioavailability and leachates using neutral pH water or 1M HC1. Our results indicate that speciation is highly significant for the interpretation of bioavailability and risk assessment data; the bioavailability fractions of arsenic in soils from Watson are small and therefore the healthy impact upon the environment and humans due to this element is limited.  相似文献   
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We reviewed the literature on the Mg++ cation with special attention on the clinico-therapeutical, physiopathogenic, and biochemical aspects. We extended the survey to some pathologies such as cardiovascular diseases and diabetes mellitus, given our understanding that a deficiency of this ion may constitute a primary cardiovascular risk factor. The dissociation present between the levels of intracellular and serum Mg++ is shown, since it may invalidate results that follow. We place special emphasis on the necessity to treat certain pathologies with magnesium salts and to quantify, with successive studies, the amount to administer.  相似文献   
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BACKGROUND: A rapid, selective and sensitive gas chromatographic method is described for the analysis of four fungicides—pyrimethanil, metalaxyl, penconazol and dichlofluanid, widely used in vineyards—in must and wine, as well as samples during alcoholic fermentation. The effect of alcoholic fermentation on pyrimethanil concentration in synthetic and real musts was studied. RESULTS: The proposed method was based on liquid–liquid extraction followed by gas chromatography with nitrogen–phosphorus detector. n‐Hexane was the most appropriate solvent for extracting the target fungicides in synthetic and real samples. Quality parameters of the proposed method presented good recovery (ca 78.3% for almost all compounds) and precision (between 1.4% and 6.1%), and quantification limits lower than maximum residue limits. However, for dichlofluanid recovery levels of well over 100% were found. CONCLUSIONS: There was no matrix effect in the analysis of pyrimethanil, metalaxyl or penconazol, but this effect was observed for dichlofluanid in synthetic and real matrices. The application of the fermentative process on pyrimethanil fungicide caused a high decrease in the concentration of this compound, and no product appeared in degradation. The decrease of pyrimethanil in fermented samples was similar in both synthetic and real samples. Copyright © 2009 Society of Chemical Industry  相似文献   
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Vitis vinifera (variety Tempranillo) grapes were processed by pulsed light (PL) at several treatment conditions before fermentation. The effect on grape external structure, wild microbial populations, phenol extraction and wine composition was monitored. PL treatments decreased significantly microbial loads in grapes. After treatment, the grapes were inoculated and fermented with Saccharomyces cerevisiae following fermentation during 2 weeks with skins and seeds. Temperature was set at 22 °C. PL treatments control wild microorganisms, especially yeasts, facilitating the growth and development of the yeast starter affecting wine quality. PL treatments of grapes can help to increase the shelf-life in postharvest technology but also improve fermentative purity and wine quality. PL is cheaper and easier to scale-up at winery than high hydrostatic pressure, pulsed electric fields or e-beam irradiation.  相似文献   
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Protein tyrosine phosphatase 1B (PTP1B) is a very promising target for the treatment of metabolic disorders such as type II diabetes mellitus. Although it was validated as a promising target for this disease more than 30 years ago, as yet there is no drug in advanced clinical trials, and its biochemical mechanism and functions are still being studied. In the present study, based on our experience generating PTP1B inhibitors, we have developed and implemented a scaffold-hopping approach to vary the pyrrole ring of the pyrrolo[1,2-a]quinoxaline core, supported by extensive computational techniques aimed to explain the molecular interaction with PTP1B. Using a combination of docking, molecular dynamics and end-point free-energy calculations, we have rationally designed a hypothesis for new PTP1B inhibitors, supporting their recognition mechanism at a molecular level. After the design phase, we were able to easily synthesize proposed candidates and their evaluation against PTP1B was found to be in good concordance with our predictions. Moreover, the best candidates exhibited glucose uptake increments in cellulo model, thus confirming their utility for PTP1B inhibition and validating this approach for inhibitors design and molecules thus obtained.  相似文献   
47.
The complete nucleotide sequence of RNA 3 of a Spanish isolate of cucumber mosaic virus (CMV-24) has been determined. The encoded putative cell-to-cell movement protein (3a protein) and the coat protein are 279 and 218 amino acids long, respectively. The 3a protein was expressed in Escherichia coli using the vector pT7-7 and was used to raise an immunoserum. We have followed the time course of accumulation of the 3a protein, in parallel to that of the coat protein, and its subcellular localization as a function of time after CMV-24 infection on tobacco plants. The maximum accumulation level of the 3a protein was reached at early stages of infection, being detected in the cytosolic and the cell wall fractions. At later stages of infection, a decline in accumulation levels of the 3a protein was observed, and the protein was essentially associated with the cell wall fractions. These data were corroborated by immunocytochemistry performed in both infected and 3a-expressing transgenic tobacco plants.  相似文献   
48.
A prospective study of 116 consecutive Kinemax cemented posterior cruciate ligament-retaining total knee arthroplasties was carried out. Similar surgical technique was used with a single variable: 61 were implanted using intramedullary guides on the tibia and 55 were implanted using extramedullary guides on the tibia. A radiographic study was performed after at least 1 year of follow-up to evaluate postoperative component position and compare the difference in the accuracy of positioning of the femoral and tibial components. Radiographic analysis showed that satisfactory position was achieved using both types of instrumentation. No statistically significant difference was observed in either the coronal or sagittal plane of the femoral component and the sagittal plane positioning of the tibial component. However, the coronal plane positioning of the tibial component revealed a statistically significant difference (P < .01), with intramedullary guides being superior to extramedullary guides. Also observed, was that using either technique, patients with less accurate postoperative positioning tended to be obese, with wide intramedullary canals. Patients with significant extraarticular deformities, marked bowing, and those with prior surgery or fractures may not be suitable for intramedullary guides, and they may require the use of extramedullary guides and intraoperative radiographic control. The ideal indication for the use of intramedullary instrumentation is in the patient who is not obese, with no extraarticular deformity, and with a well-defined, but not excessively wide, tibial medullary canal. Since tibial component malalignment in general, and coronal plane malalignment in particular, may adversely affect the long-term survival of total knee arthroplasties, the use of intramedullary alignment instrumentation is recommended when possible.  相似文献   
49.
BACKGROUND: A quantitative, selective and sensitive high‐performance liquid chromatographic method is described for the analysis of new fungicides cyprodinil, fludioxonil and their commercial formulation Switch in model solutions of must and wine, as well as samples during alcoholic fermentation. A study of the dissipation of residues was carried out. RESULTS: The proposed method is based on liquid–liquid extraction (LLE) followed by high‐performance liquid chromatography and diode array detection. Dichloromethane was the most appropriate solvent for extracting cyprodinil and fludioxonil in samples. Quality parameters of the proposed method presented good recovery (ca. 97% for almost all compounds) and precision (between 4.8% and 5.4%), and limits of quantification were lower than maximum residue limits (MRLs) in grapes. CONCLUSIONS: There is no matrix effect in the analysis of cyprodinil and fludioxonil. The application of the fermentative process on cyprodinil and fludioxonil fungicides causes a decrease in the concentrations of these compounds. This decrease is slightly higher, the higher the initial concentration, without observing the appearance of any product in degradation. Fludioxonil shows a higher reduction when the compounds are presented together in Switch. Copyright © 2008 Society of Chemical Industry  相似文献   
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