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qm -3- , 4° 0,15M NaCl, 5M , 4M - pH=7,6, ( 275–295 , –b o , A 193 , –A225). , +20° 0.15M H2PO4.  相似文献   

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Zusammenfassung Die Synthese von 7-Hydroxy-5,6-dimethoxybenzofurano[3,2:3,4]coumarin aus 7,2-Dihydroxy-oder 7-Benzyloxy-2-hydroxy-4,5-dimethoxyisoflavon wird beschrieben.  相似文献   

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Summary Starting from 17-hydroxy-17-hydroxymethyl-4-androsten-3-one, we synthesized 4-chloro-17-hydroxy-17-hydroxymethyl-4-androsten-3-one-17, 20-acetonide and 17-hydroxy-17-hydroxymethyl-1, 4-androstadien-3-one. 11, 17-dihydroxy-17-hydroxymethyl-4-androsten-3-one was obtained from cortisone via methyl-17-hydroxy-3, 11-dioxo-4-etienate.  相似文献   

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- . Ovis musimon (2n=54) O. orientalis (2n=54) - - -O. canadensis mexicana (2n=54) O. musimon x O. canadensis 12 - . 2 27 . - .

Supported by National Science Foundation Grant no. GB 32114X and the Sprague Foundation. We thank Dr. T. C. Hsu for assistance in making the chromosome preparations and for advice and encouragement. The Trustees of the Rachelwood Wildlife Research Preserve generously allowed the biopsy of specimens of their custody. Mr.Arthur Popham kindly provided the specimens from Iran while Dr.R. M. Robinson obtained biopsies from the desert sheep.  相似文献   

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Summary Over three years, theAdh and -Gpdh loci have been studied in two cellar populations ofDrosophila melanogaster and in two field populations which were each near to one of the cellars. Analyses of gene frequencies indicate that the divergence among subpopulations is greater in theAdh locus than in the -Gpdh locus. Selection for or againstAdh S allele acting on theIn(2L)t inversion influences of the -Gpdh alleles. This phenomenon may contribute to explain the maintenance of theAdh and -Gpdh polymorphism and of theIn(2L)t inversion.  相似文献   

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rII T2L , rII T4B. rII T2L rII T4B. T2L rII T4B.  相似文献   

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Although there is widespread agreement that many cancers have environmental causes we are often unable to see associations between specific cancers and exposure to environmental chemicals. One might also speulate that the more widespread, common-place and normal a chemical exposure is perceived to be then the less likely it will be that the exposure is recognised, let alone be considered to cause cancer. Widespread contamination of air by chemicals associated with internal combustion may be an example of one such invisible carcinogenic exposure. Yet evidence is available which suggests that many leukaemia and lymphoma cases, as well as other cancers, may be caused by this mundane and ubiquitous environmental contamination. The hypothesis is developed that leukaemia clustering as well as national leukaemia incidence may be related to non-occupational exposure to benzene formed by petrol combustion and resulting from petrol evaporation1. The possible association between exposure to fuel vapours, internal combustion products and cancer merits much closer examination than it receives at present.  相似文献   

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Conclusion Changes of the vessel capacity resulted from the pressor synocarotid reflexes, intestinal chemoreflexes and reflexes from the right atrium or ventricle and electric stimulation of the somatic nerve afferents can be either similarly or differently directed as compared with the responses of the resistance vessels.
, , , .
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Zusammenfassung Während unserer Untersuchungen über die mikrobiologische Dehydrierung verschiedener 16-Methylsteroide durch Bakterienkulturen vonCorynebacterium simplex, wurde eine neue Art von Umwandlung beobachtet. Von 16-Methyl-9(11)-pregnen-17, 21-diol-3, 20-dion-21-acetat ausgehend, gelang es aus den Kulturfiltraten 16-Methyl-1, 4-pregnadien-9, 11-epoxy-17, 21-diol-3, 20-dion zu isolieren. In einigen Fällen wurde auch das4-Derivat dieser Verbindung als Nebenprodukt erhalten.  相似文献   

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a aaa a aa aa a a E. coli aa, a aa aa a , a a aa - a .

Laboratory of Biological Investigations.

Laboratory for Chemistry of Antibiotics.  相似文献   

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Conclusion (1) The maximal reactions of cerebral resistance vessels arise at the stimulation frequency of 30 cps, the maximal reactions of capacitance vessels at the frequency of 10 cps. (2) Reactions of resistance vessels in the pulmonary lobe increase in the range of stimulation frequencies from 11–50 cps, maximal reactions of pulmonary capacitance vessels are observed at the frequency of 30–40 cps. (3) Reactions of resistance vessels situated below the abdominal aorta bifurcation increase progressively in the range of frequencies from 6–50 cps, the magnitude of capacitance vessel reaction reaching its maximum value at 20 cps.
30 /, — 10 /. 50 /. 30–40 /, 20 /.
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Zusammenfassung Es wird über die Herstellung des 16-Methylprednisons berichtet, welche vom Hecogenin ausgehend über ca. 15 Stufen durchgeführt wird. Als wichtige Zwischenstufe treten 5-Pregn-16-en-3-ol-11, 20-dion-Acetat und 16-Methylen-5-pregnan-3, 17-diol-11, 20-dion auf: letzteres wird durch eine stereospezifische katalytische Reduktion in das entsprechende 16-Methyl-derivat umgewandelt.  相似文献   

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