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991.
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993.
The effect of single allele substitutions into an isogenic background in Oregon-R inbred lines of Drosophila melanogaster on courtship and mating patterns has been studied. A comparison has been made between the white locus w, wco, we, the wild type w+, cn, bw, and cn bw to test the effect of eye pigmentation in influencing courtship and mating patterns. It was found that w, we, wco, cn, and bw females were more successful in mating than were wild-type and cn bw females, cn bw females being less successful than wild-type females. Also, w and cn bw males were equally successful in mating but less successful than wild-type males during the 20-min test period. The mutant males performed as well as the wild-type after courtship was initiated. The behavioral parameters measured were (1) courtship latency, the time from exposure of male to female until orientation; (2) mating speed, the time from beginning of orientation of male to female until successful copulation, and (3) copulation time.  相似文献   
994.
作为当今业界流行的模块化硬件平台标准——AdvanedTCA标准的补充,MicroTCA硬件技术标准主要针对的是网络通信、医疗影像处理、嵌入式控制、军工等市场的中低端应用。其高带宽、模块化、灵活性、高性价比等优势使其能够被运用到较为广泛的应用领域,成为当今构建高性价比模块化标准硬件平台的优选标准。众所周知,MicroTCA平台中承载的是Advanced-MC(AMC)模块。  相似文献   
995.
OBJECTIVE: Before balloon dilation, failure of compensatory enlargement and even arterial shrinkage are frequently observed at the lesion site in response to plaque accumulation. Balloon angioplasty may be regarded as artificial remodeling to enlarge the artery. The prevalence of the different types of arterial wall remodeling after applied stretch by balloon angioplasty is unknown. METHODS AND RESULTS: In 181 patients an intravascular ultrasound study was performed after coronary balloon angioplasty (n = 200 lesions). The vessel area was measured at a proximal and distal reference site and at the lesion site. Subsequently, the relative vessel area [(Vessel area lesion site)/Vessel area reference site) x 100] was calculated. Lesions were classified in three groups on the basis of their relative vessel areas: > or =105%, <105% but >95%, and < or =95%. A relative vessel area > or =105%, indicating enlargement compared with the reference site, was observed in 84 (44%) lesions. A relative vessel area <105% but >95% was observed in 43 (22%) lesions. A relative vessel area < or =95%, indicating "shrinkage" compared with the reference site, was observed in 66 (34%) lesions. CONCLUSIONS: After balloon angioplasty, the vessel area was found to be smaller compared with the reference site in 34% of the lesions. This small vessel area at the lesion site compared with a reference site may be a reflection of insufficient stretch by balloon angioplasty.  相似文献   
996.
997.
BACKGROUND: Numerous clinicians and researchers have expressed concern about the necessity and potential adverse consequences of many cesarean births in the United States. The purpose of this study was to explore college students' attitudes and beliefs about cesarean section. METHODS: One hundred two college students (66% women) completed a 20-item questionnaire that asked if they viewed cesarean delivery as a potentially negative experience, as a normal or acceptable method of childbirth, and as medically necessary, and asked about their beliefs concerning risk and prevention of cesarean birth. RESULTS: The number of "undecided" responses in the study was striking (7.8% to 69.6% across the 20 items). In general, women and men responded similarly, although women were significantly more likely than men to say they would be profoundly disappointed if their babies had to be delivered by cesarean section. Despite expressing cynicism about the cesarean birth rate (40% agreed that many unnecessary cesarean births occurred) and not viewing the procedure as a normal way of giving birth (47%), most respondents (over 70%) disagreed that giving birth by cesarean would be a negative experience or would make a woman feel like a failure. CONCLUSION: A high level of uncertainty exists about certain aspects of cesarean birth among young women and men, highlighting the need for information for prospective parents. Most college students did not view the cesarean birth experience as either potentially negative or normal. Future research should explore coverage of cesarean birth in childbirth education classes and the roles physicians, nurses, and midwives play in preparing expectant parents for the possibility of cesarean delivery.  相似文献   
998.
Cellular aspects of remodeling in intact arteries have not been fully investigated, mainly due to the lack of an appropriate methodology that allows for simple measurements. The aim of this study was to develop a method based on laser scanning confocal microscopy (LSCM), compare it with previous methodology, and apply it to the study of remodeling in hypertension. The morphology of mesenteric resistance arteries from stroke-prone spontaneously hypertensive rats (SHRSP) and Wistar-Kyoto rats (WKY) was determined with wire myography on one segment with a standardized diameter setting (0.9[d100]) and with perfusion myography on a second segment from the same artery at the calculated equivalent pressure. The second segments were stained with the nuclear dye Hoechst 33342 (live tissue) or propidium iodide (fixed tissue) and measured with LSCM and MetaMorph software. Compared with wire myography, perfusion myography showed similar differences from those previously reported. Compared with LSCM, perfusion myography showed a similar lumen but significantly smaller wall thickness in both live and fixed tissue, probably due to measurement underestimation. In the study with LSCM, arteries from SHRSP compared with those from WKY showed (1) reduced lumen, (2) altered cell density that was significantly increased in the adventitia, decreased in the media, and unchanged in the intima, (3) significantly increased medial volume, (4) significantly smaller endothelial cell nuclei, and (5) adventitial-like cells in the media. We conclude that (1) LSCM is a reliable and straightforward method to study morphology in intact vessels, (2) it provides new information on the cellular changes in remodeling, (3) adventitia might play an active role in the process of remodeling in hypertension, and (4) endothelium "remodels" in hypertension.  相似文献   
999.
Previous studies have shown that as rat cerebellar granule cell cultures differentiate in the presence of 25 mM KCl, they "up-regulate" their ability to form inositol phosphates and release Ca2+ from internal stores in response to the activation of phosphoinositidase C-linked muscarinic and metabotropic receptors. Here we show that they simultaneously up-regulate their ability to respond to inositol 1,4,5-trisphosphate (InsP3) by increasing InsP3 receptor (InsP3R) expression. In contrast, if granule cells are maintained at the more physiological KCl concentration of 5 mM, most cells undergo apoptosis, although a significant number survive. The surviving cells, however, express few InsP3Rs, suggesting that an influx of Ca2+ through voltage-dependent channels is required for InsP3R up-regulation. In addition, we have determined that these cultures express two genetically distinct InsP3R types, but that only one, the type I receptor, is expressed in granule cells. Type II receptors are also present but are found exclusively in astrocytes, which are a minor contaminant of granule cell cultures. This segregation of InsP3R types explains a previous observation, showing that the muscarinic agonist carbachol causes the reduction or "down-regulation" of type I but not type II InsP3Rs.  相似文献   
1000.
Adolescent's reasons for not using drugs were examined for evidence of factors that might lead to differential resistance to drug use. Six thousand eight-hundred and forty-one sixth, eighth, tenth, and twelfth grade students were administered a comprehensive drug survey which included: 1) demographic information, 2) reasons not to use drugs, and 3) self-reports of lifetime and current (30-day) drug use across sixteen drug categories. The reasons for not using drugs were then factor analyzed and the results compared to a "Depth of Acceptance" (DOA) model consisting of four orientations: External Outcome, Social, and Personal. These orientations are thought both to represent distinct immunization factors and to be differentially related in strength to lifetime and current drug use. Confirmatory factor analysis revealed a close fit between the hypothesized orientations and factor loadings among the sixteen items. Collectively, the sixteen items were also found to be excellent predictors of both lifetime and current drug use. While multiple stepwise regression analyses did reveal differential predictive strengths between orientation and drug use, the misclassification of a single item apparently attenuated the results for Social Orientation. The DOA model appears to provide a useful framework for "fine-tuning" prevention messages based on factors that immunize against drug use.  相似文献   
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