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51.
HM Jin NG Copeland DJ Gilbert NA Jenkins RB Kirkpatrick M Rosenberg 《Canadian Metallurgical Quarterly》1998,54(2):316-322
The induction of Fos protein was examined within LHRH neurons of guinea pigs; the aim was to delineate relationships between subgroups of LHRH neurons during an LH surge in a laboratory rodent in which the distribution of LHRH neurons and the presence of a true luteal phase in the reproductive cycle resemble those in primates. Approximately one third of the forebrain population of LHRH neurons was examined in ovariectomized steroid-treated guinea pigs killed either before or during a steroid-induced LH surge. LHRH/Fos double-labeled neurons were more abundant in surging compared to presurge guinea pigs (p = 0.008) and were most abundant within the preoptic area and anterior hypothalamus. Nonetheless, double-labeled LHRH/Fos neurons were observed throughout the remainder of the population of LHRH neurons in surging guinea pigs. A relative loss of LHRH reaction product was detected by image analysis in the LHRH terminals in the median eminence of surging guinea pigs, consistent with augmented LHRH release. Thus, there appears to be a coordinated increase in Fos expression in subgroups of LHRH neurons, more pronounced in rostral, as compared to caudal, regions in guinea pigs killed after the peak of the steroid-induced LH surge. 相似文献
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Bahman Sheikh Philip N. Storrs Thomas J. Jones Joyce S. Hsiao William R. Kirkpatrick 《Desalination》1981
The Monterey Wastewater Reclamation Study for Agriculture (MWRSA) has Completed its first year of a five-year pilot effort to investigate and to demonstrate feasibility of food crop irrigation with reclaimed municipal effluent. The project comprises a 96-plot field trial for statistical comparison of three water treatments: an eight-hectare commercial scale farm for demonstration of water reclamation for growing lettuce, broccoli, cauliflower, celery, and artichokes; an aerosol study, a virus assay, market studies, and other ancillary investigations. First year results preliminarily indicate that the main hypothesis of the study will prove to be true, i.e. “raw-eaten food crops irrigated with properly treated municipal wastewater effluent are safe for human consumption”. 相似文献
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Convective heat transfer through apertures such as doorways can be an important process by which thermal energy is transferred from one zone to another zone of a building. In this article, interzonal natural and forced convection in a two- and a three-zone, full-scale building are examined. Aperture velocity and temperature distributions are measured and the experimental interzonal mass flow rate and heat transfer are determined. A model based on zone temperature distributions is derived to predict the interzonal mass flow rate and heat transfer. The measured and predicted interzonal flow rate and heat transfer are compared and found to be in good agreement. 相似文献
55.
M. Kirkpatrick N.L. Shields T.R. Malone R.G. Brye P.N. Frederick 《Mechanism and Machine Theory》1977,12(5):439-450
This paper presents results of man-in-the-loop tests of manipulator systems. These tests were performed as part of an effort to specify man-machine interface requirements for earth orbital teleoperator systems. The entire test sequence was designed to permit quantitative evaluation of a manipulator system in terms of general manipulative tasks and tasks specifically required for remote servicing of satellites. Comparison tests were carried out using two existing manipulators and control systems to perform a fine positioning task. 相似文献
56.
DL Kirkpatrick M Kuperus M Dowdeswell N Potier LJ Donald M Kunkel M Berggren M Angulo G Powis 《Canadian Metallurgical Quarterly》1998,55(7):987-994
The interactions of a series of 2-imidazolyl disulfide antitumor compounds with the thioredoxin reductase(TR)/thioredoxin (hTrx) redox system have been studied. Disulfides III-2 (n-butyl 2-mercaptoimidazolyl disulfide) and VI-2 (ethyl 2-mercaptoimidazolyl disulfide) were substrates for reduction by TR with Km values of 43 and 48 microM. Disulfides IV-2 (1-methylpropyl 2-mercaptoimidazolyl disulfide) and DLK-36 (benzyl 2-mercaptoimidazolyl disulfide) were competitive inhibitors of the reduction of hTrx by TR with Ki values of 31 microM. None of the disulfides were substrates for reduction by human glutathione reductase. The disulfides caused reversible thioalkylation of hTrx at the redox catalytic site as shown by the fact that there was no thioalkylation of a mutant hTrx where both the catalytic site Cys32 and Cys35 residues were replaced by Ser. In addition, the disulfides caused a slower irreversible inactivation of hTrx as a substrate for reduction by TR, with half-lives for III-2 of 30 min, for IV-2 of 4 hr, and for IX-2 (t-butyl 2-mercaptoimidazolyl disulfide) of 24 hr. This irreversible inactivation of hTrx occurred at concentrations of the disulfides an order of magnitude below those that inhibited TR, and involved the Cys73 of hTrx, which is outside the conserved redox catalytic site, as shown by the resistance to inactivation of a mutant hTrx where Cys73 was replaced by Ser. Electrophoretic and mass spectral analyses of the products of the reaction between the disulfides and hTrx show that modification of 1-3 Cys residues of the protein occurred in a concentration-dependent fashion. The disulfides inhibited the hTrx-dependent proliferation of MCF-7 breast cancer cells with IC50 values for III-2 and IV-2 of 0.2 and 1.2 microM, respectively. The results show that although the catalytic sites of TR and hTrx are reversibly inhibited by the 2-imidazolyl disulfides, it is the irreversible thioalkylation of Cys73 of hTrx by the disulfides that most probably accounts for the inhibition of thioredoxin-dependent cell growth by the disulfides. 相似文献
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Chlorambucil N-oxide (CHLN-O) was synthesized and evaluated for in vitro bioreductive antitumor activity. A time-dependent hypoxic differential was observed when EMT6 cells were exposed to CHLN-O in the presence of rat liver microsomes and reducing equivalents. The cytotoxicity of the N-oxide was potentiated under hypoxia, and augmented further by a combination of low pH and hypoxia. Metabolic studies were also undertaken, which utilized previously described HPLC methodology for the analysis of CHLN-O loss from biological fluids. These demonstrated the requirement for microsomal enzymes and reducing equivalents, and also illustrated the time-dependent manner of CHLN-O loss from isolated microsomal preparations. 相似文献