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1.
A Smith  C Folsome  K Bahadur 《Experientia》1981,37(4):357-359
Organo-molybdenum microstructures were prepared by visible light irradiation of ammonium molybdate, formaldehyde, ammonium phosphate and a mineral solution. These microstructures are shown to be capable of carbon dioxide photoreduction, nitrogenase activity, and water decomposition, and may represent a metabolic stage between the nonliving and the living.  相似文献   

2.
Résumé La dépolarisation de la membrane des cellules adipeuses brunes, produite par l'administration in vivo de noradrénaline, est aussi accompagnée d'une augmentation de la perméabilité mesurée par une augmentation de la résistance membranaire.

Supported in part by research grant NASA No. NGR-05-004-035.  相似文献   

3.
Zusammenfassung Nachweis, dass die alkalische Hydrolyse des Phthalimids durch eine N-Succinimidgruppe erhöht wird. Während der alkalischen Hydrolyse des Polysuccinimids fällt die Reaktionsgeschwindigkeit infolge Auftretens negativer Ladungen ab.

Contribution No. 251 of the Institute for Space Biosciences. The Florida State University, Tallahassee, Florida, financial support by NASA grant No. NsG-173-62. We thank Dr.M. Kasha for use of facilities of the Institute for Molecular Biophysics. We thank Mr. Ch.R. Windsor for performing amino acid analyses.  相似文献   

4.
Zusammenfassung 20 h nach Bestrahlung mit letaler Röntgenstrahlendosis (2000 r) zeigten winterschlafendeCitellus tridecemlineatus Herabsetzung der Konzentration von Catecholaminen in Leber und Niere. Werden Veränderungen des Wassergehaltes im Gewebe mitberücksichtigt, so erscheint der Gehalt an myokardialen Catecholaminen unverändert.

Acknowledgments. This research was aided by Grants HE-06312, USPHS; and Ns G-271-62, NASA. The authors are grateful to DoctorD. E. Smith, Division of Biological and Medical Research, Argonne National Laboratory, for providing the ground squirrels and the facilities for their hibernation and radiation.  相似文献   

5.
Résumé La réduction de l'effet calorigénique de la noradrénaline chez des rats adaptés au froid, dont la veine de Sulzer a été ligaturée et sectionnée, est semblable à celle obtenue chez des rats sans graisse brune interscapulaire. Etant donné l'absence de signe de nécrose de la graisse brune chez les rats à veine ligaturée, cette observation ne parle pas en faveur d'une fonction endocrine de ce tissu.

Supported in part by research grant NASA No. NGR-05-004-035. A preliminary report of this work was presented at the 1971 meeting of the Federation of American Societies of Experimental Biology; and an abstract of this talk is contained in Federation Proceedings30, 319 (1971).  相似文献   

6.
研究美国登月火箭的项目管理有助于我国探月工程的规划。2004年美国公布重返月球计划。为实现这一目标,美国国家航空航天局决定以航天飞机推进系统为基础研制新型运载火箭。新火箭于2006年被命名为“战神”,包括“战神”-1乘员运载火箭和“战神”-5货物运载火箭两种型号。目前,“战神”-1火箭已完成系统需求评审,进入设计评审阶段。火箭第一级、上面级、上面级发动机以及电子设备的研制合同都已于2007年授出。预计2009年5月进行首次试验飞行,2015年3月进行首次载人飞行。而“战神”-5火箭还处于早期研究阶段。由于预算调整和航天项目的复杂性,“战神”火箭的研制已经有所拖延。虽然大型航天集团和国家航空航天局努力争取更多预算,但“战神”火箭未来的研制不排除进一步拖延的可能。  相似文献   

7.
Résumé Chez des rats adaptés au froid, non anesthésiés, placés brièvement dans une atmosphère de 12% d'oxygène, on observer un arrêt immédiat de la thermogénèse de la graisse brune. Cet effet semble s'expliquer par l'absence d'activation par le système sympathique. L'absence d'une réaction de thermogénèse en réponse à une injection de noradrénaline chez des rats soumins au froid et dans des conditions hypoxiques plaide en faveur de cette explication.Supported by research grant NASA No. NGR-05-004-035. The counsel and assistance given by Dr.R. Em. Smith, Dr.J. M. Horowitz and Dr.B. A. Horwitz is gratefully acknowledged.  相似文献   

8.
本文研究栅极动态信号在功率器件故障预测上的应用.首先介绍了功率器件栅极动态信号反映的相关失效机制,并分析了栅极动态信号的老化特征及影响因素.提出了老化特征提取方法,选定动态过程时间,动态过程面积比率作为老化特征.使用降频错位采样的方法还原高频采样下计算的老化特征,降低利用动态信号进行故障预测的采样频率,以提高方法可行性.通过NASA公布的数据集进行实验验证,提取的老化特征明显,降频采样达到了预期效果.  相似文献   

9.
Résumé Les effets de l'ablation des ganglions cervicals supérieurs deCoturnix coturnix japonica font l'objet de cet exposé. Chez le mâle la gangliectomie bilatérale n'affecte pas l'activité testiculaire. Par contre chez les femelles la quantité d'ufs pondus est nettement réduite et l'interruption post-opératoire de la pondaison est prolongée; de plus la première ponte des jeunes femelles est retardée. LesCoturnix qui ont subi l'ablation des ganglions ont un taux de mortalité plus élevé lorsque les oiseaux sont exposés à des abaissements de température et des changements de photopériodisme.

This work was supported in part by USPHS research grant No. NB 04171-83 and by NASA research grant No. NGR 05-004-028.  相似文献   

10.
Zusammenfassung Adrenalinzufuhr wie auch hochfrequente elektrische Reizung am pontinischen Gehirnstamm führen zu Potentialverstärkung, wenn diese nicht visuell, sondern auditiv geweckt wurde. Entsprechende Versuche mit Acetylcholin führten zu keinem Erfolg, was für die Spezifität der retikularen Einflüsse spricht.

Supported by NSF grant No. GB 4706-X to J. S. and NASA predoctoral fellowship to T.D.L.  相似文献   

11.
J D Desai  V V Modi 《Experientia》1977,33(12):1592-1593
The ammonia uptake in A. nidulans was found to be linear for about 20 min, and was proportional up to 1.5 mg/ml dry cell density. The transport of ammonia does not involve energy. Normal and biotin deficient A. nidulans showed an identical Km-values of 10.26 X 10(-5) M ammonia for uptake. The uptake of ammonium ion has been shown to be regulated by the intracellular concentration of ammonia.  相似文献   

12.
The question of whether ammonium uptake influences the occurrence of ureides in legumes has been addressed in this study by investigating threeP. vulgaris genotypes as well as one cultivar ofGlycine max. All plants were raised in sand culture during the dry season in northern Thailand and irrigated daily with nitrogen-free nutrient solution, or the same solution containing 12 mol m–3 nitrogen in the form of (NH4)2SO4 or KNO3, each treatment consisting of different proportions of either compound. Regression analyses of xylem sap composition relative to ammonium vs. nitrate supply of plants harvested at V4, R1 and R6 indicated close positive correlations of xylem amino nitrogen content and negative correlations with xylem nitrate content and ammonium supply. Statistically significant correlations between relative xylem ureide content and ammonium availability could be established for theP. vulgaris cultivar Brilliant up to stage R1, but not for the other plants investigated. It was concluded that at least for some genotypes of common bean a relationship exists between ureide production and ammonium uptake by the root system. Since the extent to which ureide production is stimulated remains quite small, its relevance to the xylem solute technique for measurement of N2 fixation may be limited. Nevertheless, due to the possibility of large genotypic differences in the impact of ammonium on ureide production, this factor must be considered in calculations if N2 fixation is to be determined in soils containing significant amounts of ammonium, e.g. in paddy fields.  相似文献   

13.
新型脱氮工艺及其可控因素的分析   总被引:2,自引:0,他引:2  
简要的回顾了传统的生物脱氮工艺。介绍了基于亚硝化及其厌氧氨氧化的新型微生物脱氮工艺SHARON工艺、ANAMMOX工艺、SHARON和ANAMMOX组合工艺、CANON工艺,并对过程的原理及其影响因素进行了探讨,为高浓度的氨氮废水提供了可操作性发展前景。  相似文献   

14.
Summary Of several quaternary ammonium derivatives tested, 1-allyl-1-(3,7-dimethyloctyl)piperidinium bromide showed the best growth-retarding activity. OnChrysanthemum morifolium the growth retardation obtained with a single application of 100–200 ppm compared favourably with that obtained from 2–3 applications of 3400 ppm of N-dimethylaminosuccinamic acid (daminozide).  相似文献   

15.
在沈阳市郊浑河和蒲河两岸开展不同植被配置方式下,开展河岸植被缓冲带对地表径流中铵氮污染消减研究。结果表明:河岸植被缓冲带越宽,水中铵氮浓度越高,其对地表径流中铵氮的消减作用越明显;天然植被比人工植被能更好的去除铵氮污染物;当污染浓度升高时,林草混合配置的植被带对铵氮表现出较好的消减率;人工林草地和天然林草地对铵氮的平均消减率分别为31%和25.9%,最高消减率分别为57.9%和63.3%,最高消减率均发生在7m宽度河岸带上,而人工林地对铵氮的消减效果较差。实验结果能够应用于指导自然河岸带的生态保护与人工河岸植被带的建设。  相似文献   

16.
J J Stragand  R F Hagemann 《Experientia》1975,31(11):1375-1376
An improvement in the technique for the radioimmunoassay of cyclic-AMP, wherein ammonium sulfate precipitation is replaced with zirconyl phosphate gel, is presented. This substitution produces a more stable pellet than that obtained with ammonium sulfate. This greatly reduces a potential source of error due to pellet instability.  相似文献   

17.
Zusammenfassung Norepinephrin fördert in vitro die Tätigkeit einer Ouabain empfindlichen Na+/K+ ATPase. Diese Wirkung, durch eine geringe Dosis eines-adrenergischen Antagonisten eingeschränkt, scheint offenbar von einer 3,5-zyklischen AMP unabhängig zu sein. Die Tätigkeit der Brenzkatechin-induzierten ATPase stimmt mit der Auffassung überein, dass im aktivierten braunen Fettgewebe der Energieumsatz zusammen mit dem vermehrten Sauerstoffverbrauch ansteigt.

Supported in part by research grants NASA No. NGR-05-004-035 and USPHS No. HD-03268. P.A.H. is a PHS predoctoral fellow (No. 1-GM-33, 505-04). A preliminary report of this work was presented at the 1969 Fall meeting of the Am. Physiol. Society; an abstract of this talk is contained in The Physiologist12, 257 (1969). We thank J. F.Detrick for his technical assistance.  相似文献   

18.
Summary After 7 days of space flight house flies,Musca domestica, exhibited similar longevity, but a reduction in reproductive output as compared to earthbound controls. This reduction was not observed in later generations. These data suggest that space flight directly alters the rate of ovarian development, but that this effect is not genetically transmitted.Acknowledgment. We thank Todd E. Nelson, student participant in the Space Shuttle Student Involvement Project, John T. Jackson, NASA/Johnson Space Center, and James R. Peterson, Honeywell, Inc. for providing us with the flies and information related to the in-flight experiments.  相似文献   

19.
The microstructures of the magnesium billets could be improved markedly by low-frequency electromagnetic casting(LFEC)processing.In fact,the low-frequency electromagnetic field(LFEF)also has favorite effect on the surface quality of billet.However,few public reports on the surface quality of LFEC magnesium billets could be found.Therefore,a new crystallizer with a metal internal sleeve together with a kind of lubricant was designed aiming at lowing surface turning quantity,and the effects of casting velocit...  相似文献   

20.
以十二烷基苯磺酸(DBSA)为掺杂剂和乳化剂,过硫酸铵(APS)为引发剂,采用乳液插层聚合(emulsion intercalated polymerization)方法合成了十二烷基苯磺酸掺杂聚苯胺/有机蒙脱土纳米复合材料(简称PANI-DBSA/organo-MMT).研究表明,在苯胺、DBSA、APS三者物质量比为1:1:1时,苯胺与有机蒙脱土(organo-MMT)质量比为1:3时,复合材料的电导率最高可达2.63 ×10-2 s/cm.用XRD、FT-IR、TGA和SEM对复合材料进行了表征,结果表明PANI-DBSA能够有效地插层到有机蒙脱土层间,并在蒙脱土表面形成包覆结构,形成连续的导电相,从而使复合材料具有良好的导电性.TGA试验结果表明复合材料的热性能较本体聚合物得到有效改善.  相似文献   

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