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111.
The impact of high temperatures (24 to 39 degrees C) and low to moderately high humidities (20 to 70%) on the applicability of TLC systems for drug identification was studied during a 6 month climatologic cycle in Burkina Faso (West Africa). In general, the Rf values as observed on the plates were found to be substantially affected as compared with values obtained at temperate climates. Some TLC systems were more affected than others and the largest deviations of up to 30 Rf units were at low humidities. Tropical conditions also had a negative effect on the reproducibility of Rf values. However, when an Rf-correction procedure was applied, using reference mixtures of known drugs on each plate, accuracy as well as reproducibility of the resulting Rfc values were drastically improved and data thus corrected were found to be compatible with existing TLC data bases developed under moderate climatological conditions. The impact of high to extremely high humidities (70 to 100%) remains to be investigated. 相似文献
112.
Washington University v. Catalona revolves around ownership of tissue samples provided by patients for research purposes, raising significant ethical and legal questions concerning patient rights, current human research practices, and the treatment of samples as capital resources by the research institution. 相似文献
113.
In this study, a new method was developed for the impurity profiling of illicit MDMA tablets. The extraction efficiency, linearity, repeatability and reproducibility of the method were evaluated. Eighty two MDMA tablets coming from presumed unrelated large seizures in 2004 (n >500 tablets) were analyzed by gas chromatography mass spectrometry (GC-MS) in order to assess the discrimination power of the method. The latter was found to be practical, robust, relatively easy to perform, highly discriminative and yielding good chromatography. In addition, some new impurities were detected and identified. Their chemical structures and mass spectra are reported. 相似文献
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C. Haedrich C. Ortmann O.R. Hofmann J. Seilwinder A. Klein 《Forensic Science International Supplement Series》2006,160(2-3):173-177
In a case of suicidal application of electricity differences between the rectal temperature of the body and the suspected time of death were observed.In order to answer the question whether an electric current from hand to hand over >30 min led to a rise in body temperature FEM-based computer simulations and animal experiments were carried out. Both resulted in a warming of the soft parts in the arm without warming the body core. Thus a temperature-based estimation of the time since death can also be used in cases with electricity as the cause of death. Besides, in the animal experiment we found a spontaneous rise in the body core temperature even without application of electricity which may be a reason for the typical temperature plateau after death. 相似文献
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Silvina J. Vilas-Ghiso Diana M. Liverman 《International Environmental Agreements: Politics, Law and Economics》2007,7(2):137-169
More than a decade after NAFTA (North American Free Trade Agreement) entered into force, the environmental effects of agricultural
trade liberalization in Mexico are still controversial, emerging, and not fully understood. This paper contributes to the
literature that aims to explore trends in input use in the agricultural sector in Mexico during the post-NAFTA period among
both commercial/industrial and traditional/rainfed farmers, and examines the influence of the national and multilateral institutional
framework on these outcomes. We decompose the post-NAFTA agricultural production data into scale, technique and composition
effects to estimate the impact that trade liberalization has had on the use of fertilizer and land use, two key agricultural
inputs for which reliable aggregate data is available. We conclude that among commercial farmers patterns of crop type specialization
and significant technological improvements have led to some declines in fertilizer use but they have been offset by growth
in fertilizer use associated with growing agricultural output. Among traditional farmers increased output and specialization
in land-intensive grain crops are contributing to an increase in land under cultivation and technological improvements show
the potential, but not yet not the strength, to counteract these effects. We analyse the environmental institutional framework
and rural development plans, observing that institutional weaknesses have, in several instances, reduced the environmental
benefit of technique and composition effects. We conclude with recommendations about how the Mexican agricultural sector might
reap the environmental benefits of international agricultural trade. 相似文献
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