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111.
Parathyroid hormone and 1,25-dihydroxyvitamin D3 had opposite effects on calf renal 25-hydroxyvitamin D3 24-, 23-, and 1 alpha-hydroxylase activities. Parathyroid hormone administration increased renal 25-hydroxyvitamin D3-1 alpha-hydroxylase activity 7-fold while 25-hydroxyvitamin D3-23- and 24-hydroxylase activities were essentially the same as controls. Administration of 1,25-dihydroxyvitamin D3 increased 25-hydroxyvitamin D3-23-hydroxylase and 24-hydroxylase activities 4-fold and decreased 25-hydroxyvitamin D3-1 alpha-hydroxylase activity to undetectable concentrations. Vitamin D deficiency increased 25-hydroxyvitamin D3-1 alpha -hydroxylase activity 13-fold, and 25-hydroxyvitamin D3-23-hydroxylase and 24-hydroxylase activities were undetectable. These results confirm previous reports with regard to control of renal 25-hydroxyvitamin D3-24-hydroxylase and 1 alpha -hydroxylase in other species and represent new findings relative to the control of 25-hydroxyvitamin D3-23-hydroxylase. Plasma P was lower and 1,25-dihydroxyvitamin D3 higher in calves treated with parathyroid hormone, and Ca and 1,25-dihydroxyvitamin D3 were lower in the vitamin D-deficient calves. 1,25-Dihydroxyvitamin D3-treated calves had higher plasma P and lower Mg than controls. Further studies using this calf model should lead to better understanding of Ca-regulating hormones control of vitamin D metabolism. 相似文献
112.
1,10-diaze [8]crown-6, their N,N'-dibutyl- and dioctyl-substituted derivatives and the structure analogous open-chein tetreoxedieza slkanee have been synthesized in order to examine the extraction properties for Na+, K+, Sr2+ and Hg2+. It wes found, that the extraction of strontium, potassium and sodium picratee with azacrown compounds ie much higher than that with open-chein oxaaze alkanes. 1,10-diaze [18] erown-6 has a good selectivity for the extraction of Sr2+ over K+ and Na in alkaline solution. In the case of Sr2+ the diffarencea between tha various azacrown compounds are email, whereea in the caee of K+ and Na the substituted derivativee are better extractante. Theserssulte correspond qualitativsly with tha order of stebility conetantB in protic solvsnts. The extrectebility of N,N'-dioctyl-l, 10-dieze[18]crown-6 for HgCl2 is very high. Contrerv to the order of stability conetants the uneubetituted conpound do not extract mercury under the choeen experimental condition*. The extraction power of open-chain conpounde ie aleo high and strong Influenced by the alkyl eubatltuente at the nitrogen donor stons, 相似文献
113.
Image segmentation or registration approaches that rely on a local search paradigm (e.g, Active Appearance Models, Active Contours) require an initialization that provides for considerable overlap or a coarse localization of the object to be segmented or localized. In this paper we propose an approach that does not need such an initialization, but localizes anatomical structures in a global manner by formulating the localization task as the solution of a Markov Random Field (MRF). 相似文献
114.
Horst Brodowsky Matthias Albus Qiyuan Chen Zhongliang Xiao Zhoulan Yin 《Journal of Electronic Materials》2011,40(5):907-914
The thermoelectric power of Rh and Ir was redetermined between 100 K and 1400 K. It varies almost linearly from +1.7 μV K−1 to −3.8 μV K−1 for Rh and from +1.5 μV K−1 to −2.2 μV K−1 for Ir. The diffusive part of the thermopower could be calculated from the density of states. It is approximately equal to
the temperature dependence of the electrochemical potential of the electrons divided by the electronic charge. This is attributed
to the approximate establishment of local equilibrium between electrons and lattice atoms above 400 K—a condition not fulfilled
in the phonon-drag regime below 300 K. 相似文献
115.
In a series of 3 experiments modeled after infant studies, 3- to- 6-year-old children’s intuitive knowledge about support was assessed. Different objects were shown either sufficiently supported or not. Children had to predict whether a block would remain standing on a platform upon release or make perceptual judgments about the possibility of a shown block-on-platform configuration. Overall, performance was strongly age-related and independent of task context. Sensitivity for the amount of contact between object and support was clearly evidenced for each of the age-groups tested and was almost perfect in 5- and 6-year-olds. By contrast, sensitivity for the proportion of an object’s volume positioned over the support was only marginally reliable in 3-year-olds and still far from perfect in 6-year-olds. It is concluded that basic intuitions about support undergo distinct developmental change beyond infancy and are not yet fully developed in kindergartners. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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Zusammenfassung In diesem Beitrag wird ein Überblic über die Probleme vermittelt, die sich bei der Konfiguration und dem Betrieb eines flexiblen Fertigungssystems stellen. Die zur Behandlung der wichtigsten Problemtypen verfügbaren Modellierungsansätze werden systematisch beschrieben und auf ihren möglichen Einsatz zur Entscheidungsunterstützung für die betriebliche Praxis hin untersucht. 相似文献
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