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排序方式: 共有1383条查询结果,搜索用时 15 毫秒
21.
CE Verrijt MJ Kroos MI Huijskes-Heins HG van Eijk JP van Dijk 《Canadian Metallurgical Quarterly》1998,19(7):525-530
BACKGROUND: Glucocorticoids have been linked to self-administration of a wide range of drugs in animals and are increased endogenously by chronic nicotine intake. Corticosteroids have also been shown to regulate nicotine receptor sensitivity and to be involved in behavioral sensitization to nicotine. METHODS: Cortisol levels and cortisol suppression in response to dexamethasone were measured in a sample of smokers participating in a smoking cessation treatment trial. RESULTS: Cortisol levels dropped significantly during the early quitting process (2 weeks post-quit) and returned to a level below baseline 1 month post-quit. The magnitude of the initial drop in cortisol was strongly related to post-quit distress and marginally predictive of abstinence. Neither baseline nor post-quit changes in percent cortisol suppression after dexamethasone were related to abstinence success or withdrawal distress. CONCLUSIONS: Withdrawal from cigarette smoking is marked by a reduction in cortisol levels that appears to be related to the degree of distress experienced during the early quitting period. Further work is needed to determine whether withdrawal-related cortisol changes or distress are predictive of abstinence success. 相似文献
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We describe the case of a young woman with pain on turning her head attributable to a malformation of the hyoid bone. Diagnosis was established using spiral computed tomography with the patient's neck in the position of greatest discomfort and with 3-dimensional reconstruction of the hyoid bone. Prior conventional radiography and magnetic resonance imaging did not aid in finding a diagnosis. After surgical removal of both greater cornua of the hyoid bone there was a complete relief of symptoms. 相似文献
23.
When European laboratories decided to develop a digital sound broadcasting system (DSB), they specified three main conditions to fulfil:
- quality improvement up to the level of ‘CD’ sound, even in difficult reception conditions (mobile vehicles, etc)
- additional significant digital data transmissions in order to transform sound broadcasting into a really new service
- the possibility of a common system for satellite and terrestrial transmissions.
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T. Koltai M. Macaud A. Milenkovic E. Schultz M. Lemaire M. Vrinat 《Catalysis Letters》2002,83(3-4):143-148
While deep hydrodesulfurization of gas oil is more and more important, elimination of sulfur compounds such as 4,6-dialkyldibenzothio-phenes still attracts considerable attention. A new process based on the association of a separation process by charge-transfer complex (CTC) formation and classical catalytic hydrotreating (HDT) was evaluated. The results indicated that a CTC pretreatment allows the rate of hydrodesulfurization (HDS) to increase and the final sulfur level to decrease. This process is even more efficient for feeds difficult to desulfurize. 相似文献
27.
Stefano Panebianco Klara Berg Jean-Christophe David Mohamed Eid Uwe Filges Friedrich Gröschel Arnaud Guertin Alexander Yu Konobeyev Christian Latgé Sébastien Lemaire Sylvie Leray Alain Letourneau Markus Lüthy Franco Michel-Sendis Selene Scazzi Gediminas Stankunas Nicolas Thiollière Leonhard Tobler Luca Zanini 《Annals of Nuclear Energy》2009
The MEGAPIE project aimed to design, build and operate a liquid metal spallation neutron target of about 1 MW beam power in the SINQ facility at the Paul Scherrer Institut (Villigen, Switzerland). This project is an important step in the roadmap towards the demonstration of the accelerator driven system (ADS) concept and high power liquid metal targets in general. Following the design phase, an experimental program was defined to provide a complete characterization of the facility by performing a “mapping” of the neutron flux at different points, from the center of the target to the beam lines. The neutronic performance of the target was studied using different experimental techniques with the goals of validating the Monte Carlo codes used in the design of the target; additionally, the performance was compared with the solid lead targets used before and after the MEGAPIE experiment. 相似文献
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Hox genes are expressed in dynamic patterns during embryogenesis consistent with their role in axial specifications. To study the distribution of mouse Hoxc8, a homeodomain containing protein, we raised monoclonal antibodies against the least conserved portion of Hoxc8. Using these antibodies, we have examined early and mid-gestation embryos for the distribution of the protein. At the end of gastrulation Hoxc8 is expressed in the caudal portion of the embryo. In the neural tube, an early phase when all cells express Hoxc8 is distinguished from a late phase with predominant expression in differentiating neurons. A comparison of this expression pattern with that of a reporter gene under the control of the early Hoxc8 enhancer demarcates three separate regulatory components: (1) initiation and establishment; (2) maintenance; and (3) downregulation. We propose that Hoxc8 expression during embryogenesis is established in multiple phases. Possible regulatory mechanisms involved in generating such a complex domain of Hox gene expression are discussed. 相似文献
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HG Klein 《Canadian Metallurgical Quarterly》1996,33(4):275-276