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提出了在对命题题材进行恰当地描述的基础上计算机自动命题的思想;并给出了一种具体的题材描述模型,以及在该模型上基于集合和逻辑运算的机器命题规则,试用结果表明:机器命题是可行的且具有很好的开放性、多样性和实时性。  相似文献   

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Sera of healthy students (from Academy of Paris) aged between 18 and 30 years were collected with a view to routine clinical testing. 50 samples each representing the pooled sera of 400 individuals were investigated by evaluating 7 proteins for each pooled sample. Calculations of standard deviations showed that there existed a significant reproductibility of less than 2% for the population as a whole. These pooled sera representing 20 000 individual blood samples are proposed as a standard of human serum proteins.  相似文献   

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The principle amatoxin, alpha-amanitin, is found to be extremely sensitive toward lactoperoxidase catalyzed degradation, rather than iodination, of the indole nucleus. Extensive attenuation of inhibitor potency against eukaryotic DNA-dependent RNA polymerase II accompanies the treatment of alpha-amanitin with lactoperoxidase, iodide and hydrogen peroxide.  相似文献   

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Zusammenfassung Bei einem den bovinen Thrombozyten anliegenden Mikroorganismus werden elektronenmikroskopisch beschrieben: Polymorphe 1.5·0.4 µ messende Gebilde mit feiner Plasmamembran an der Oberfläche und ribosomenähnlichen Strukturen im Innern, die Ähnlichkeit mit Mycoplasma, Eperythrozoen und Haemobartonellen zeigen.  相似文献   

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In an attempt to gain information about the identity of the Golgi apparatus casein kinase(s) (G-CK), responsible for the phosphorylation of caseins in lactating mammary gland, the proteins present in fractions enriched in G-CK activity eluted from DEAE-Sepharose and heparin-Sepharose columns were resolved by two-dimensional electrophoresis and analyzed by mass spectrometry. This led to the identification of 47 proteins altogether, none of which is a bona fide protein kinase. At least 9 of the identified proteins however, are readily phosphorylated by co-purifying G-CK activity, and 7 are physically associated with it to give supramolecular complex(es) of about 500 kDa as judged from Superdex S200 gel fitration and glycerol gradient ultracentrifugation experiments. In contrast, the apparent molecular weight of G-CK estimated from an in gel activity assay after SDSPAGE and renaturation is about 41 kDa. Many of the proteins phosphorylated by and/or associated with G-CK belong to the category of chaperonines, including HSP90, GRP-94 and −78, and various isoforms of protein disulfide isomerases, suggesting a global role of this kinase in the modulation of protein folding. Received 21 October 2005; received after revision 30 November 2005; accepted 6 December 2005 †These authors contributed equally to this work.  相似文献   

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Summary Pyrolysis of cannabidiol, one of the major constituents of Cannabis sativa, yields a mixture of components. Next to previously identified products, a major conversion product has now been isolated and identified. The unusual and stereospecific route of formation of this compound with altered chromophore is discussed.Acknowledgments. This research was supported by the Dutch Department of Public Health and Environmental Hygienics. Thanks are due to R. D. van Ooyen who provided technical assistance, Dr M. J. A. de Bie and Dr W. Heerma for valuable discussions, Drs J. W. Marsman and Ir T. Spoormaker for performing PMR experiments.  相似文献   

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Résumé Le nouveau diterpène galdosol (I) a été isolé de laSalvia canariensis L. et sa structure déterminée comme 7-oxo-11, 12-dihydroxy-8, 11, 13-abiétatrién-20, 6-olide.  相似文献   

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Targeted polymeric micelles for delivery of poorly soluble drugs   总被引:17,自引:0,他引:17  
Polymeric micelles (micelles formed by amphiphilic block copolymers) demonstrate a series of attractive properties as drug carriers, such as high stability both in vitro and in vivo and good biocompatibility, and can be successfully used for the solubilization of various poorly soluble pharmaceuticals. These micelles can also be used as targeted drug delivery systems. The targeting can be achieved via the enhanced permeability and retention effect (into the areas with the compromised vasculature), by making micelles of stimuli-responsive amphiphilic block copolymers, or by attaching specific targeting ligand molecules to the micelle surface. Immunomicelles prepared by coupling monoclonal antibody molecules to p-nitrophenylcarbonyl groups on the water-exposed termini of the micelle corona-forming blocks demonstrate high binding specificity and targetability. Immunomicelles prepared with cancer-specific monoclonal antibody 2C5 specifically bind to different cancer cells in vitro and demonstrate increased therapeutic activity in vivo. This new family of pharmaceutical carriers can be used for the solubilization and targeted delivery of poorly soluble drugs to various pathological sites in the body.  相似文献   

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Epidermal homeostasis - a numerical model. Kinetics of epidermal cells   总被引:1,自引:0,他引:1  
E Aschheim 《Experientia》1968,24(1):94-98
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Résumé Un modèle cinétique simple a été développé pour l'épiderme; les lois cinétiques de premier ordre peuvent lui être appliquées fructueusement. Il est envisagé que la régulation homéostatique de l'épiderme peut se faire par l'ajustement des quantités de nourriture qui lui parviennent. Le flux nutritif atteignant l'épiderme est composé du flux de diffusion, qui prédomine normalement, et du flux actionné par l'évaporation, à la surface de la peau, de l'eau provenant de l'ultra-filtrat du sérum. Ce dernier pourrait prédominer quand l'épiderme aurait été lésé, et serait augmenté quand la peau ne constituerait pas une barrière suffisante au passage de l'eau.Par analogie avec les cultures de microbes en «steady state», il est envisagé que le nombre total de cellules épidermiques par unité de surface cutanée et leur taux de croissance sont des fonctions du taux du transfert de nourriture à l'épiderme. L'équation hyperbolique deMonod est donc modifiée et appliquée à l'épiderme. Une évaluation approximative de cette équation suggère que le flux nutritif vers l'épiderme est augmenté en cas de psoriasis aussi bien que dans la peau normale lorsqu'elle est dépouillée du stratum corneum. On considère que dans le psoriasis le dérangement cinétique de l'épiderme et le dérangement fonctionnel de la barrière de la peau au passage de l'eau sont intimement liés.

This research was supported by N.L.H. Research Grant No. HE 03833-08. The author is a recipient of N.I.H. Research Career Development Award No. HE 12,476-03.  相似文献   

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Résumé La glande surrénale bovine contient un enzyme qui réagit avec l'angiotensinogène pour former de l'angiotensine. L'enzyme est distribué dans toute la glande surrénale, en plus grande quantité dans la médullosurrénale et dans la veine centrale. Vu les effects bien connus de l'angiotensine sur la sécrétion de l'aldostérone et sur les catécholamines de la médullosurrénale, il est possible que l'enzyme «rénine-semblable» influence les fonctions spécifiques de la glande surrénale.  相似文献   

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D A Lightner  C S Pak 《Experientia》1976,32(9):1107-1109
An oxodipyrromethene model compound for bilirubin is found to undergo oxidation to a blue tetrapyrrole and a water-propentdyopent on a silica gel thin layer chromatography plate. The reaction involves ground state oxygen and requires silica gel, although the propentdyopent is an expected product from reaction with singlet oxygen.  相似文献   

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W H Boyd  A Peters  G Morris 《Experientia》1978,34(8):1090-1092
Cells of the anterior lobe of the bovine hypophysis, show an affinity for immunoglobulins IgG, IgA and IgM. The phenomenon either provides a message to stimulate cellular secretion or to excite mechanisms associated with the synthesis and release of Ig's or their determinants.  相似文献   

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