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Zusammenfassung In der Arbeit wird nachgewiesen, da\ durch Röntgenbestrahlung des N-Acetyl-DL-valins und des Glycyl-DL-valins ebenso wie beim Valin freie Radikale der Form (CH3)2C-R gebildet werden, die sich durch Abtrennen eines H-Atoms ergeben. Au\erdem wird über das Vorkommen mehrerer Radikalarten bei den einzelnen Substanzen berichtet. Für mehrere Radikale sind die Werte für den isotropen Anteil der Hyperfeinstrukturaufspaltung der Linien des ESR-Spektrums angegeben.
Electron spin resonance spectroscopy of free radicals produced in DL-valine, D-valine, N-Acetyl-DL-valine, and Glycyl-DL-valine by X-irradiation
Summary Free radicals produced in polycrystalline DL-Valine, D-Valine, N-Acetyl-DL-valine, and Glycyl-DL-valine by X-irradiation were studied by electron spin resonance spectroscopy. The structure of some of them was found to be (CH3)2C-R, formed by loss of the H as known already in the case of valine. Additionally we have to conclude from our results presented in this paper the existence of several types of radicals in the named substances X-irradiated. For the unpaired spin of some radicals the values of isotropic hyperfine coupling constants are given.


Herrn Prof. Dr. A. Schraub zum 60. Geburtstag gewidmet.  相似文献   

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小穗发育是决定水稻产量的主要农艺性状,鉴定控制小穗发育的关键基因对研究和分析调控农艺性状的分子机理是至关重要的.本文中,我们鉴定了一组小穗数目明显减少的突变体,命名为decteased spikelets(des),这里详细研究des2和des5两个突变体.结果显示des2是由单基因隐性位点控制,图位克隆将此位点定位到6号染色体的长臂上,并最终克隆了此基因,发现des2是moc1的一个新的等位突变体.定位克隆和序列分析显示在des5中,LAX基因的编码HLH(螺旋一环一螺旋)结构域的区域发生了一个点突变,暗示des5是lax的一个新的等位突变体.我们的结果暗示小穗和水稻叶腋分枝的发育受相同的遗传途径调控.  相似文献   

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Ohne Zusammenfassung  相似文献   

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Aus dem Andesitgebiet des Kremnitzer Gebirges (Mittelslowakei) wird eine vegetationskundliche Analyse der wichtigsten Weidegesellschaften dargelegt. Die Talweiden stellt die AssoziationLolio-Cynosuretum Tx. 1933 dar. Sie ist nur wenig verbreitet u. zw. in der Subassoziationtypicum. Eine ähnliche Gesellschaft wird in der Form einer Sammeltabelle aus dem Tal des Slaná-Flusses angeführt. Am meisten sind die Bergweiden verbreitet, die durch die AssoziationAnthoxantho-Agrostietum Sillinger 1933 em.Jurko 1969 repräsentiert werden. Die für niedrigere Lagen charakteristische SubassoziationA.—A. typicum kann in zwei Varianten gegliedert werden, eine oligotrophe mitOnonis spinosa und eine eutrophe (gemäht und beweidet) mitRhinanthus minor. Die SubassoziationA.—A. nardetosum subass. nova ist in Höhen von über 700 m anzutreffen. Die bisher veröffentlicheten Tabellen dieses Typs wurden einer syntaxonomischen Revision unterzogen und im Rahmen dieser Subassoziation mehrere Varianten herausgestellt. Die selteneren Halbtrockenrasen im Kremnitzer Gebirge werden provisorisch nur alsBrachypodium pinnatum-Gesellschaft dargestellt. In zwei Aufnahmen aus diesem Gebiet wird dasNardetum montanum Sillinger 1933 dokumentiert. Endlich wird ganz kurz eine wirtschaftliche Bewertung dieser Gesellschaften angeführt.  相似文献   

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Analysis of the setal system was conducted on the maxillipeds of Gonodactyloidea, which includes the smashers, a functional group of stomatopods. Generally, the homogeneity of the setal system is demonstrated in stomatopods. However, examination of maxillipeds of Gonodactyloidea reveals that some setal types are systematic characters at levels of families or species. The smashers group has a very homogeneous setal system in three families: Gonodactylidae, Odontodactylidae and Protosquillidae. The setal analysis of maxillipeds confirms the functional role of these appendages. Like other morphological characters, the setal system of stomatopods has co-evolved with behavioral patterns in both groups: spearers and smashers.  相似文献   

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The study of polyelectrolytes in solution by small-angle x-ray scattering techniques involves special problems, raised by the presence of several species: solvent, macroions, counterions, and possibly the ions of an additional electrolyte. A theoretical treatment of this problem is developed, based upon geometric concepts; the treatment applies to globular and to rodlike particles for the case of x-ray experiments carried out on an absolute scale. The equation obtained involves several parameters: mass and radius of gyration for globular particles; mass per unit length and axial radius of gyration for rodlike particles; partial specific volumes of the neutral macromolecular component of the counterions and of the added electrolyte; solvation of the macromolecular species; fraction of the counterions osmotically free. The equation is used to interpret a series of experiments performed with the Li, Na, and Cs salts of DNA in solution in water containing variable amounts of the chlorides of each cation. The effects of concentration are first eliminated by extrapolating to infinite dilution the experiments carried out at different concentrations; then the effects of the solvation are eliminated by extrapolating to pure water the results obtained at different electrolyte concentration. The parameters still involved at this stage are the mass per unit length, the partial specific volumes of the DNA and of the counterions, and the fraction of the counterions osmotically free. If the partial specific volumes are chosen in agreement with other data of the literature, and if the fraction of the counterions osmotically free is assumed to be 0.30 for the three salts, as suggested by other workers, the structure of the DNA molecules turns out to be the same for three cations, and to agree with the Watson-Crick model. These results are confirmed by the study of the liquid–crystalline gels, obtained at higher concentration, that lead to a direct determination of the mass per unit length of the rods. Moreover the solvation of the DNA molecules is determined as is shown to be different for each of the three cations. These results are in excellent agreement with those obtained by other techniques.  相似文献   

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