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排序方式: 共有699条查询结果,搜索用时 15 毫秒
1.
E Kievit FB van Gog HM Schlüper GA van Dongen HM Pinedo E Boven 《Canadian Metallurgical Quarterly》1997,38(4):813-823
The effects of arginine vasopressin (AVP) and oxytocin (OT) upon thyroid-stimulating hormone (TSH), free thyroxine (FT4) and free triiodothyronine (FT3) release were studied in euthyroid rats. Intracerebroventricular (i.c.v.) infusion of AVP in doses of 0.5 ng or 5 ng led to significant increases in plasma levels of TSH as well as FT4 and FT3. The effects of OT injected i.c.v. in similar doses were not consistent (there was no parallel between the changes of respective hormones plasma levels). It may be concluded that vasopressin modulate the pituitary-thyroid system function; AVP is probably a physiological stimulator of TSH and thyroid hormones secretion. 相似文献
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Hurst P.J. Lewis S.H. Keane J.P. Aram F. Dyer K.C. 《IEEE transactions on circuits and systems. I, Regular papers》2004,51(2):275-285
Several Miller compensation schemes using a current buffer in series with the compensation capacitor to modify the right-half-plane zero in fully differential two-stage CMOS operational amplifiers are analyzed. One scheme uses a current mirror as a current buffer, while the rest use a common-gate transistor as a current buffer. The gain transfer functions are derived for each topology, and approximate transfer-function coefficients are found that allow accurate estimation of the zero(s) and poles. 相似文献
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SL Nyberg HJ Mann MY Hu WD Payne WS Hu FB Cerra RP Remmel 《Canadian Metallurgical Quarterly》1996,24(6):643-648
OBJECTIVE: The initially well-fixed implants of total hip replacement (THR) are in the long-term subject to aseptic loosening. Many cytokines can contribute to osteolysis due to osteoclast recruitment and/or activation. However, in this respect tumor necrosis factor-alpha (TNF-alpha) plays a pivotal role, because it upregulates interleukin-1 and 6 and granulocyte-macrophage colony stimulating factor. The aim of this study was to assess the eventual presence, cellular localization and extent of expression of TNF-alpha in the synovial-like membrane at the implant or at the cement to bone interface compared to control synovial membrane. METHODS: Twenty samples from the synovial-like membrane of the periprosthetic tissues were compared to control samples. TNF-alpha containing cells were visualized using an avidin-biotin-peroxidase complex (ABC) method and analyzed by light microscopy, double labelling and image analysis. RESULTS: TNF-alpha was found in the periprosthetic tissues in fibroblasts and vascular endothelial cells, but mainly in the macrophages was it found to coincide with areas containing implant-derived debris. TNF-alpha containing cells were more numerous in the synovial-like membrane in the interface tissue from the proximal stem area (2816 +/- 318 cells) than in the control synovial membrane (565 +/- 93 cells, p < 0.01). Interestingly, similarly high TNF-alpha expression (3452 +/- 582 cells) was also seen in the synovial-like membrane of the pseudocapsule. CONCLUSION: These findings suggest that the foreign body-type host reaction caused by THR is characterized by the high expression of TNF-alpha. Because such expression occurred in the interface tissue between the implant and surrounding bone, TNF-alpha, due to its pivotal direct and indirect role in the activation and recruitment of osteoclasts, may contribute to periprosthetic osteolysis and to the loosening of THR. 相似文献
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P Demoly D Jaffuel KF Chung J Bousquet FB Michel P Godard 《Canadian Metallurgical Quarterly》1996,25(40):2025-2030
The efficacy of corticosteroids in asthma has been recognized over 40 years ago. Since that time, the advent of inhaled forms has further improved the therapeutic of these drugs which are now recognized as the fundamental treatment for asthma, and described in detail by national and international consensus. Based on a large body of literature, it can now be recommended to prescribe inhaled corticosteroids for symptomatic asthma patients. Long-term treatment is required and dosage not exceeding 1000 micrograms/d (beclometasone dipropionate equivalent) in adults are safe. Differences in the pharmacological characteristics of the various systematic and inhaled corticosteroids can be used to adapt treatment and administration route to each patient and achieve good patient compliance with optimal therapeutic efficacy. 相似文献
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UV absorbance spectroscopy is the most common method for detecting nucleic acid structural transitions and obtaining thermodynamic parameters. UV-detected melting has been used to determine stabilities of nucleic acid hairpins, duplexes, triplexes, and higher order structures and to determine thermodynamic effects of unusual or modified bases and mismatched base-pairs. We report that in some cases UV absorbance spectroscopy is an inadequate analytical technique for these purposes. Some critical transitions are invisible to UV absorbance spectroscopy. For example, the conversion of dodecamer d(CGCAAATTCGCG) from hairpin to random coil is not accompanied by hyperchromism. Circular dichroism (CD) spectroscopy (263 nm) clearly detects two transitions for this dodecamer, each giving a pronounced change in ellipiticity. The concentration dependence of the low-temperature transition and the concentration independence of the high-temperature transition indicate that the predominant state converts from duplex to hairpin to random coil as the temperature increases. These assignments are confirmed by comparison to oligonucleotides of similar sequence that undergo a hairpin to coil transition only. In contrast to CD spectroscopy, UV absorbance spectroscopy shows only a single transition. The transition detected by UV absorbance spectroscopy corresponds to the low-temperature transition detected by CD. UV absorbance spectroscopy does not detect the second transition at any wavelength (from 218 to 310 nm) (by changes) in either absorbance or its derivative with temperature. 相似文献
10.
Mena, a relative of VASP and Drosophila Enabled, is implicated in the control of microfilament dynamics 总被引:3,自引:0,他引:3
FB Gertler K Niebuhr M Reinhard J Wehland P Soriano 《Canadian Metallurgical Quarterly》1996,87(2):227-239
This paper examines the effects of exposure to mass media messages promoting family planning on the reproductive behaviour of married women in Nigeria using cross-sectional data. Longitudinal data are also used to ensure that exposure to media messages pre-dates the indicators of reproductive behaviour. Cross-sectional analysis suggests that: (1) contraceptive use and intention are positively associated with exposure to mass media messages, and (2) women who are exposed to media messages are more likely to desire fewer children than those who are not exposed to such messages. Similarly, analysis of the longitudinal data shows that exposure to mass media messages is a significant predictor of contraceptive use. Thus, exposure to mass media messages about family planning may be a powerful tool for influencing reproductive behaviour in Nigeria. 相似文献