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71.
The stereoelectronic requirements for interaction of the southern aliphatic hydroxyl of cannabimimetic pharmacophores with the CB1 and CB2 receptors are explored. The stereoselective syntheses of three series of classical/nonclassical hybrid cannabinoids are described. These compounds were designed to investigate the importance of the southern aliphatic hydroxyl (SAH) pharmacophore for cannabimimetic activity. Variation in the chain length of the SAH moiety in these 6beta-(hydroxyalkyl)dihydrobenzopyran analogues, from 6beta-hydroxymethyl to 6beta-(omega-hydroxyethyl) and 6beta-(omega-hydroxypropyl), and the effects of replacing the hydroxyl functionality by hydride and iodide are reported. Our results indicate that the SAH pharmacophore has less pronounced effects than the C-3 aliphatic chain on cannabinoid activity. Furthermore, it appears that this southern molecular component is capable of interacting with two different subsites on the receptor and that the nature of this interaction is determined by the terminal substituent on the C-6beta alkyl group. One of the subsites can accommodate the relatively polar SAH pharmacophore, while the second subsite interacts with more hydrophobic C-6beta substituents and can accommodate large spherical pharmacophores separated by three methylene carbons from the tricyclic cannabinoid template.  相似文献   
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Recent work has identified negative-acting DNA regulatory elements that function to prevent the expression of neuronal genes in non-neuronal cell types or in inappropriate neuronal subtypes. In some cases, the protein factors that interact with these silencer elements have been isolated and characterized. For example, the recently cloned silencer-binding factor NRSF/REST is a novel zinc-finger protein that interacts with silencer elements in a number of neuron-specific genes. These data suggest that negative regulation plays a major role in determining the diverse patterns of gene expression within the nervous system.  相似文献   
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Our research team is involved in ongoing research in both worksites and medical office settings. These settings offer great potential for reaching individuals who would not otherwise participate in health promotion, but they also place considerable constraints on assessment time and efforts, especially if one's goal is to attract a high and representative proportion of employees or patients. This paper reports on our experience with measures of dietary behavior in these two settings. We found it problematic to collect detailed assessments such as 4-day food records or comprehensive food frequency/history checklists in worksites or medical office settings using population-based samples. Instead, we recommend and provide data on the utility of a dietary-fat screening instrument, and on the Food Habits Questionnaire (FHQ-Kristal, Shattuck, & Henry, 1990), a brief measure of dietary behaviors associated with high-fat eating patterns. The FHQ, in particular, was found to correlate well with other more costly and time-consuming methods of assessment, to be reliable and responsive to intervention effects, and to provide behavioral targets for intervention. The strengths and limitations of these measures for tailoring intervention and assessing outcomes are discussed.  相似文献   
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BACKGROUND: Despite concerns about its prevalence and ramifications, harassment has not been well quantified among physicians. Previous published studies have been small, have surveyed only 1 site or a convenience sample, and have suffered from selection bias. METHODS: Our database is the Women Physicians' Health Study, a large (4501 respondents; response rate, 59%), nationally distributed questionnaire study. We analyzed responses concerning gender-based and sexual harassment. RESULTS: Overall, 47.7% of women physicians reported ever experiencing gender-based harassment, and 36.9% reported sexual harassment. Harassment was more common while in medical school (31% of gender-based and 20% for sexual harassment) or during internship, residency, or fellowship (29% for gender-based and 19% for sexual harassment) than in practice (25% for gender-based and 11% for sexual harassment). Respondents more likely to report gender-based harassment were physicians who were now divorced or separated and those specializing in historically male specialties, whereas those of Asian and other (nonwhite, nonblack, non-Asian, non-Hispanic) ethnicity, those living in the East, and those self-characterized as politically very conservative were less likely to report gender-based harassment. Being younger, born in the United States, or divorced or separated were correlated with reporting ever experiencing sexual harassment; those who were Asian or who were currently working in group or government settings were less likely to report it. Those who felt in control of their work environments, were satisfied with their careers, and would choose again to become physicians reported lower prevalences of ever experiencing harassment. Those with histories of depression or suicide attempts were more likely to report ever having been harassed. CONCLUSIONS: Women physicians commonly perceive that they have been harassed. Experiences of and sensitivity to harassment differ among individuals, and there may be substantial professional and personal consequences of harassment. Since reported rates of sexual harassment are higher among younger physicians, the situation may not be improving.  相似文献   
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Although it is well established that a low-circulating level of high-density lipoprotein (HDL) cholesterol is strongly associated with the likelihood of developing atherosclerotic coronary heart disease (CHD), the causal nature of this association has not been shown. Low levels of HDL cholesterol frequently are associated with other CHD risk factors, whose correction, often by hygienic means, may reduce CHD risk with minimal risk of adverse side-effects. However, other recommended hygienic interventions may lower HDL cholesterol levels. Specific safe and effective drugs for correcting a low HDL cholesterol level are not available and the potential value of specific pharmacologic treatment of this condition in the treatment or prevention of CHD remains unproven. Thus, while HDL measurement should be incorporated routinely in risk-assessment, intervention efforts should focus primarily on lowering low-density lipoprotein cholesterol.  相似文献   
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Spin-glass models of neural networks   总被引:1,自引:0,他引:1  
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