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1.
Two types of carbonate substitution in the apatite structure   总被引:2,自引:0,他引:2  
Zusammenfassung Um die Art des Karbonateinbaues in die Apatitstruktur zu klären, wurden zwei Typen von synthetischen Karbonatapatiten untersucht: solche, die sich in wässrigen Medien bildeten, und andere, die bei hohen Temperaturen und unter Ausschluss von Wasser entstanden.  相似文献   

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Two types of viruslike particles in Drosophila midgut   总被引:1,自引:0,他引:1  
L P Gartner 《Experientia》1971,27(5):562-564
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Résumé On a trouvé des particules hexagonales, comme des virus, de deux grandeurs, dans les cellules de la partie centrale de l'intestin de laDrosophile. Les particules les plus grosses étaient dans le cytoplasme et les plus petites dans le noyau. L'apparence de la distribution de ces particules sont en fonction de l'âge de la mouche.

Part of this work was supported by research grant No. AM 12818 of the National Institute of Arthritis and Metabolic Diseases.  相似文献   

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Muscarinic acetylcholine receptors (mAChRs) play a central role in the mammalian nervous system. These receptors are G protein-coupled receptors (GPCRs), which are activated by the agonists acetylcholine and muscarine, and blocked by a variety of antagonists. Mammals have five mAChRs (m1–m5). In this study, we cloned two structurally related GPCRs from the fruit fly Drosophila melanogaster, which, after expression in Chinese hamster ovary cells, proved to be muscarinic acetylcholine receptors. One mAChR (the A-type; encoded by gene CG4356) is activated by acetylcholine (EC50, 5 × 10?8 M) and muscarine (EC50, 6 × 10?8 M) and blocked by the classical mAChR antagonists atropine, scopolamine, and 3-quinuclidinyl-benzilate (QNB), while the other (the B-type; encoded by gene CG7918) is also activated by acetylcholine, but has a 1,000-fold lower sensitivity to muscarine, and is not blocked by the antagonists. A- and B-type mAChRs were also cloned and functionally characterized from the red flour beetle Tribolium castaneum. Recently, Haga et al. (Nature 2012, 482: 547–551) published the crystal structure of the human m2 mAChR, revealing 14 amino acid residues forming the binding pocket for QNB. These residues are identical between the human m2 and the D. melanogaster and T. castaneum A-type mAChRs, while many of them are different between the human m2 and the B-type receptors. Using bioinformatics, one orthologue of the A-type and one of the B-type mAChRs could also be found in all other arthropods with a sequenced genome. Protostomes, such as arthropods, and deuterostomes, such as mammals and other vertebrates, belong to two evolutionarily distinct lineages of animal evolution that split about 700 million years ago. We found that animals that originated before this split, such as cnidarians (Hydra), had two A-type mAChRs. From these data we propose a model for the evolution of mAChRs.  相似文献   

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给出了衡量模糊推理鲁棒性的度量应有的结构,建立了基于左连续三角模的4类模糊度量空间,证明了基于Lukasiewicz蕴涵和Goguen乘积蕴涵的模糊度量空间是最适宜于展开模糊推理的两类模糊度量空间.  相似文献   

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Two types of 5-hydroxytryptamine release from isolated blood platelets   总被引:5,自引:0,他引:5  
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Zusammenfassung Durch cytologische Untersuchungen von Tumorzellen des experimentell beim MolchTriturus alpestris erzeugten Darmcarcinoms kann gezeigt werden, das der Nucleolus dieser Tumorzellen zwei Typen von Ribonucleoprotein enthält.  相似文献   

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Résumé Deux Types de réponses apparaissent dans des cellules ganglionnaires du chat soumises à des stimuli mobiles. Ils correspondent aux unités répondant de façon transitoire ou durable et proviennent d'une différence dans la disposition spatiale du centre et de la périphérie du champ récepteur.

This investigation was supported by a Public Health Research Grant No. EY00376 from the National Eye Institute, National Institutes of Health, Bethesda, Md.  相似文献   

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Summary The thermogenic response to injections of noradrenaline at thermoneutrality was substituted by thermogenesis at low ambient temperatures. This demonstrates that noradrenaline-induced heat production is equivalent to physiologically induced nonshivering thermogenesis during cold exposure.Supported by the Deutsche Forschungsgemeinschaft (He 990).  相似文献   

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Summary 4,6-Dibromoindole and 4,6-dibromo-2-methylindole have been isolated from the acorn wormGlossobalanus sp. The biosynthetic implications of this finding are discussed.We wish to thank Prof. Paul J. Scheuer, University of Hawaii for his encouragement and for use of his facilities during spectroscopic work. T.H. gratefully acknowledges the giving of a travel grant by the University of the Ryukyus Foundation for International Exchange.  相似文献   

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Zusammenfassung Morphologische Befunde an Nervenzellen der Retina von Hühnerembryonen werden mitgeteilt. Mit der Bodian-Silberimprägnation in Langzeit-Gewebekulturen konnten multipolare Ganglienzellen, bipolare und Horizontalzellen, Amakrine und Synapsen identifiziert werden.

This work was supported by the Medical Research Council of Canada.  相似文献   

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