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A novel biocatalytic reaction of transamidation of non-activated amides with amines is reported. Among 45 different lipolytic and proteolytic enzymes tested, only the lipase from Candida antarcticawas able to catalyze this reaction. The reaction proceeded with up to ca. 80% conversion in anhydrous methyl tert-butyl ether and worked with both N-substituted and unsubstituted amides. The biocatalytic transamidation is an equilibrium process and, therefore, higher conversions to the desired amide were achieved by using increased concentrations of the amine nucleophile.  相似文献   
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Illicit trade carries the potential to magnify existing tobacco-related health care costs through increased availability of untaxed and inexpensive cigarettes. What is known with respect to the magnitude of illicit trade for Vietnam is produced primarily by the industry, and methodologies are typically opaque. Independent assessment of the illicit cigarette trade in Vietnam is vital to tobacco control policy. This paper measures the magnitude of illicit cigarette trade for Vietnam between 1998 and 2010 using two methods, discrepancies between legitimate domestic cigarette sales and domestic tobacco consumption estimated from surveys, and trade discrepancies as recorded by Vietnam and trade partners. The results indicate that Vietnam likely experienced net smuggling in during the period studied. With the inclusion of adjustments for survey respondent under-reporting, inward illicit trade likely occurred in three of the four years for which surveys were available. Discrepancies in trade records indicate that the value of smuggled cigarettes into Vietnam ranges from $100 million to $300 million between 2000 and 2010 and that these cigarettes primarily originate in Singapore, Hong Kong, Macao, Malaysia, and Australia. Notable differences in trends over time exist between the two methods, but by comparison, the industry estimates consistently place the magnitude of illicit trade at the upper bounds of what this study shows. The unavailability of annual, survey-based estimates of consumption may obscure the true, annual trend over time. Second, as surveys changed over time, estimates relying on them may be inconsistent with one another. Finally, these two methods measure different components of illicit trade, specifically consumption of illicit cigarettes regardless of origin and smuggling of cigarettes into a particular market. However, absent a gold standard, comparisons of different approaches to illicit trade measurement serve efforts to refine and improve measurement approaches and estimates.  相似文献   
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J. Martin  J. B. Ross 《CMAJ》1984,130(4):421-422
A newborn child was noted to have an ulcerated lesion on the vertex of her scalp, which was diagnosed as aplasia cutis congenita. As this disorder is relatively rare and frequently misdiagnosed, this case is reported and the relevant literature reviewed.  相似文献   
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Epithelial ovarian carcinoma (EOC), the major cause of gynaecological cancer death, is a heterogeneous disease classified into five subtypes. Each subtype has distinct clinical characteristics and is associated with different genetic risk factors and molecular events, but all are treated with surgery and platinum/taxane regimes. Tumour progression and chemoresistance is generally associated with major metabolic alterations, notably altered mitochondrial function(s). Here, we report for the first time that the expression of the mitochondrial regulators PGC1α and TFAM varies between EOC subtypes; furthermore, we have identified a profile in clear-cell carcinoma consisting of undetectability of PGC1α/TFAM, and low ERα/Ki-67. By contrast, high-grade serous carcinomas were characterised by a converse state of PGC1α/TFAM, ERα positivity and a high Ki-67 index. Interestingly, loss of PGC1α/TFAM and ERα was found also in a non-clear cell EOC cell line made highly resistant to platinum in vitro. Similar to clear-cell carcinomas, these resistant cells also showed accumulation of glycogen. Altogether, our data provide mechanistic insights into the chemoresistant nature of ovarian clear-cell carcinomas. Furthermore, these findings corroborate the need to take into account the diversity of EOC and to develop subtype specific treatment strategies.  相似文献   
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Despite considerable progress in recent years in the promotion of flowering in conifers, relatively little is known about the endogenous control of sex expression or its practical manipulation to aid pollen and crop management in seed orchards. Well defined patterns of sexual zonation exist within the tree crown and shoot, and these appear to be associated with hormonal and possibly nutritional gradients. No firm conclusions, however, are possible regarding the specific role(s) of different PGRs in sex expression, this being as much as a problem of lack of critical study as the complexity of the process itself. Whether a PGR such as gibberellins or auxins, or a cultural treatment that itself may influence endogenous hormone levels, primarily promotes female or male flowering often depends on the position within the crown of the shoot being treated, and its timing in relation to stage of primordia development. Photoperiod also may be involved- short days favoring females and long days males, at least in some species- although its role in controlling sex expression is by no means clear. Practical manipulation of sex expression may be possible through selective crown pruning, different PGR combinations, treatment timing and/or photoperiod control, but the development of such techniques for operational use will require a better basic understanding of the endogenous regulatory mechanisms involved.  相似文献   
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