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Summary Mutation induction was investigated in wild-type haploid yeastSacchaomyces cerevisiae after split-dose UV-irradiation. Cells were exposed to fractionated 254 nm-UV-doses separated by intervals from 0 to 6 h with incubation either on non-nutrient or nutrient agar between. The test parameter was resistance to canavanine. If modifications of sensitivity due to incubation are appropriately taken into account there is no change of mutation frequency. 相似文献
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Jürgen Bohn Vlad Coroamă Marc Langheinrich Friedemann Mattern Michael Rohs 《人类与生态风险评估》2004,10(5):763-785
Visions of Pervasive Computing and ambient intelligence involve integrating tiny microelectronic processors and sensors into everyday objects in order to make them “smart.” Smart things can explore their environment, communicate with other smart things, and interact with humans, therefore helping users to cope with their tasks in new, intuitive ways. Although many concepts have already been tested out as prototypes in field trials, the repercussions of such extensive integration of computer technology into our everyday lives are difficult to predict. This article is a first attempt to classify the social, economic, and ethical implications of this development. 相似文献
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We present the autopsy report of a liveborn triploid female, born after 36 weeks of gestation, who died at the age of 20 hours. External features were diagnostic: fetal hypoplasia, hypertelorism, microstomia, micro-and retrognathia, preauricular skin tag, low-set ears, and 3-4 syndactylia. All internal organs were hypoplastic. There were atrial and ventricular septal defects. Adrenals and kidneys were fused, the gallbladder was absent, and ovarian hilum cell were found to be hyperplastic. Triploidy, 69xxx, was confirmed cytogenetically. The placenta was hypoplastic and, microscopically, revealed a peculiar type of immaturity, so-called hydatidiform villous hypoplasia, findings which have not been previously reported. We suggest that the generalized fetal and placental hypoplasia and the severe hypoplasia of all internal organs are caused by a proliferative deficiency of the triploid cells. In addition, the nuclear DNA content was determined by cytophotometrically from placental stromal cells and was found to be about 50% above the normal diploid DNA value; i.e., a triploid DNA value was confirmed. 相似文献
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Falk Kiefer Miguel Angel Jiménez-Arriero Oliver Klein Alexander Diehl Gabriel Rubio 《Addiction biology》2008,13(1):124-129
Naltrexone is an opiate receptor antagonist mainly at the micro-receptor that is thought to reduce the positively reinforcing, pleasurable effects of alcohol and to reduce craving. An increase in time to first relapse to heavy drinking has been the most consistent finding obtained with naltrexone, although not all trials including two of the largest have been positive. Inconsistent outcome data suggest that effectiveness varies among different subgroups of patients. This paper re-evaluates recent data on the effectiveness of naltrexone in subjects differentiated according to Cloninger Type I and II. Moreover, it combines and cross-validates results of two recent European studies that found naltrexone treatment more beneficial in alcohol-dependent patients with early age at onset of drinking problems (Cloninger Type II). It is discussed whether especially these subjects should be targeted for pharmacological relapse prevention treatment with naltrexone. 相似文献