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The properties of the semiquinone radicals produced for 2,5-bis(carboethoxyamino)-3,6-diaziridinyl-1,4-benzoquinone (AZQ) and 2,5-bis(2-hydroxyethylamino)-3,6-diaziridinyl-1,4-benzoquinone (BZQ), have been investigated. AZQ semiquinone radicals can be produced from the reduction of AZQ by superoxide radicals, whereas BZQ semiquinone radicals are unstable in the presence of oxygen. The one-electron reduction potentials of the couples Q/Q-. at pH 7.0 were determined as -70 +/- 10 mV for AZQ and -376 +/- 15 mV for BZQ. The difference in these potentials is explained. As a consequence of ESR studies on the enzymatically produced radicals, we have considered the factors which determine the detection of ESR signals for reduced quinones produced in a biological system. 相似文献
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The claim that list sizes in general practice should continue to fall towards a national average of 1700 patients rests heavily on the assumption that the extra time available to doctors would be used mainly for longer consultations, resulting in better standards of care. Evidence suggests, however, that the time is more likely to be used to increase rates of consultation in surgeries and home visits and to reduce the length of the working week. A national, random sample of 2104 principals in general practice in England and Wales were questioned about their allocation and use of time. The response rate was 67%, and no large biases in response were detected. The smaller their personal list size the less time general practitioners spent on all aspects of their work and the higher their rates of consultation and home visiting. The effects of further reductions in list sizes would be haphazard, being differentially distributed across the range of list sizes. Longer consultations would probably result, but most of the extra time would probably be used in higher rates of consultation in surgeries and home visits and some would be taken as free time. 相似文献
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This study analyzes fertility determinants in the oil region of Mexico, consisting of the states of Veracruz, Tabasco, and Campeche. Data are from the 1980 Mexican census and the unit of analysis is the municipio. The regression models, in which the dependent variables of children ever born and child-woman ratio are examined, reveal religious variables to be most significant, with greater fertility for non-Catholics and persons with no religion than for Catholics. Also of great importance are economic variables. Literacy and urbanization, both "classical" Mexican fertility variables, reduce fertility. There are major differences among three urban/rural and three indigenous language subsamples. Results are discussed vis-a-vis demographic theories and prior research. 相似文献
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Purdy LM 《Bioethics》1989,3(1):18-34
The morality of surrogate mothering is analyzed from a "consequentialist" framework which attempts to separate those consequences that invariably accompany a given act from those that accompany it only in particular circumstances. Critics of surrogacy argue that it transfers the burden and risk of pregnancy onto another woman, separates sex and reproduction, and separates reproduction and childrearing; none of these acts is necessarily wrong, either morally or for women's or society's basic interests. While surrogate mothering can be rendered immoral if women are coerced into the practice or become victims of subordinating or penalizing contracts, it has the potential to empower women and increase their status in society by providing a job that is less risky and more enjoyable than other jobs women are forced to take and by achieving greater social recognition for reproductive labor. 相似文献
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Butler NC 《Bioethics》1989,3(3):181-199
Resolution of the question of pain relief in neonates and infants has been hampered by hesitation on the part of medical personnel to assign a high priority to consideration of the issue. Butler provides a partial explanation for this hesitation based on resistance to changes in belief and practice stemming from the history of neonatology and an epistemological need for coherence. She argues for suspension of both the hesitation and the resistance, and for quickly implementing changes in infant care practices. Showing that traditional reasons for denying or diminishing infant pain perception and its control have lost their persuasive power, she offers ethical arguments for recasting traditional concerns and adopting a new perspective. 相似文献