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11.
A fusion protein was constructed between the porcine alpha2A-adrenoceptor and a pertussis toxin-insensitive (Cys351Gly) form of the alpha subunit of the G protein Gi1. Addition of agonist ligands to membranes of COS-7 cells transiently transfected to express this construct, and treated with pertussis toxin prior to cell harvest, resulted in stimulation of both high affinity GTPase activity and enhanced binding of [35S]GTPgammaS. By considering the fusion protein as an agonist-activated enzyme and measuring Vmax of GTP hydrolysis a range of agonist ligands displayed varying efficacy in their capacity to activate the receptor-associated G protein with adrenaline = noradrenaline = alpha-methylnoradrenaline > UK14304 > BHT933 > or = xylazine = clonidine. A similar rank order was observed following independent co-expression of the alpha2A-adrenoceptor and Cys351Gly-Gi1alpha. These data demonstrate the utility and applicability of using a receptor-G protein fusion protein approach, in which the stoichiometry of receptor and G protein is fixed at 1:1, to measure and further understand the nature of agonist efficacy.  相似文献   
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正如2007版国际半导体技术蓝图(ITRS)所提到的,自动测试设备(ATE)所面临的最紧迫的技术挑战便是“促进良率提高的测试”,特别是对于90、65、45nm和未来工艺节点上的晶圆工艺和器件良率学习。  相似文献   
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在测试、组装和封装TechXPOT的“成品率管理”分会上,很多与会者展示了降低不断飞升的测试成本的重要性。总的来说,与会者都能就下述观点达成一致,即随着芯片复杂性的不断提高以及器件平均售价(ASP)的不断降低,  相似文献   
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Disaster response to manmade and natural events involves the quick evacuation of the affected population to safer areas. Given the potential for large-scale loss of life and property, there is a need for effective emergency strategies to mitigate the adverse effects of these disasters. Most existing evacuation traffic management strategies focus on increasing network capacity along the evacuation direction such as contraflow lanes, but other information or routing strategies have not been fully explored. Optimal routing strategies can be presented to evacuees as recommended routes. Advising evacuees that take system-optimal routes help balance the distribution of evacuation flows among multiple evacuation routes. However, a critical aspect in evaluating the effectiveness of such strategies is to properly account for the possible evacuation route-choice behavior. This study analyzed the situation in which evacuees are given a set of system-optimal paths; evacuees choose their evacuation routes, following a certain route-choice behavior (rational, panic, etc.). Discussions focus on the extent to which the routing effectiveness can be properly estimated, subject to the route-choice behavior. This paper further proposes a behavior-robust feedback information routing (FIR) strategy to further improve system performance. The FIR is based on the concept of closed-loop control that reacts to the system state and updates the advised routes. The FIR that targets the system-optimal routing strategy has been shown to be effective and robust for real-time evacuation traffic management.  相似文献   
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Brownian motion of the hairs (stereocilia) of amphibian hair cells has been shown in experiments to be in the range of some nm. Our models of the Brownian motion of coupled harmonic oscillators with mechanical properties of stereocilia lead to similar displacements. Computer simulation shows that stochastic fluctuations enhance the encoding of low level acoustic signals. Stochastic resonance lowers the detection threshold of auditory signals to amplitudes one order of magnitude lower than that of the Brownian motion.  相似文献   
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Chronic hematic cysts are rare conditions that usually present to the ophthalmic surgeons with displacement of the globe. There is usually no, or minimal, bone involvement. Two patients with unusual presentations of chronic orbital hematic cysts are reported. These cysts resulted in significant expansion and erosion of the bony orbits. The presentation, operative findings, and reconstruction are reported and discussed.  相似文献   
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BACKGROUND: Solitary rectal ulcer syndrome is a rare disorder characterized by erythema or ulceration of the rectal wall, associated with typical histological features, and disturbed defaecatory behaviour with the passage of blood and mucus. METHODS: This is a review based on a literature search using a computer database (Medline) and manual cross-referencing. RESULTS: The pathogenesis is likely to vary in different patients; it includes trauma from straining, direct digital trauma and possibly primary neuromuscular pathology. The histological findings of extension of the muscularis mucosa between crypts and muscularis propria disorganization on full-thickness specimens are characteristic. Biofeedback defaecation retraining, including habit training, can lead to symptom improvement and return to work in a majority of patients. Abdominal rectopexy offers long-term symptom improvement in approximately 50 per cent of patients. Rectal ulceration may persist after any treatment, even if symptoms improve. CONCLUSION: Behavioural therapy and carefully considered operations offer the best treatment results. Further work on psychological factors and neuromuscular and vascular pathology is required.  相似文献   
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