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A review is presented of the various intermolecular forces important in stabilizing protein structure and association. Emphasis is put on entropic as well as enthalpic contributions to the free energy. The factors affecting size and size distribution in protein aggregates are discussed. A theory is presented for the size distribution of casein micelles, taking into account the spherical nature of the micelles and the importance of surface repulsive forces in limiting size.  相似文献   
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In this study, we examined the effects of moral reasoning level and sex role orientation on social influence in group decision making. We predicted that these two individual difference constructs would have an interactive effect such that people who are compatible or nonconflicted on the two dimensions would have more influence on a group task with moral implications than would people who are conflicted. All subjects individually completed a distributive decision task that required ranking terminally ill patients for access to a life-saving kidney machine. They then met in small groups and reached a group decision on the same task. The subjects' moral reasoning level and sex role orientation—assessed via the Rest Defining Issues Test (Rest, 1979) and the Bem Sex Role Inventory (Bem, 1974), respectively—were used to predict influence on the group decision. Influence was measured in three ways: similarity between individual and group ranks, self-rated influence, and selection of the most influential group member. The results of all three influence measures provided support for the interactive hypothesis. In the discussion we consider the implications of the data for individual difference models of moral reasoning, the need for further understanding of goal competition and personality conflict, and the importance of considering the impact of moral factors on group decision-making processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
55.
Lymphography of 123 newly diagnosed patients with lymphoma was followed by staging laparotomy without intra-operative abdominal roentgenography. These patients were retrospectively evaluated for residual abnormal nodes with postoperative abdominal roentgenography. Sixteen patients with pathologically normal nodes at laparotomy had residual lymphographically abnormal nodes at postoperative roentgenography. Nine patients received less extensive irradiation than they would have if the remaining abnormal nodes had been biopsied and found to contain tumor. Two had shortened survivals as an apparent consequence.  相似文献   
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The problem of minimising the heat input into an intermittently heated building can be transformed to a standard problem in mathematical programming. Previous limitations of this transformation to systems with constant efficiency are removed and the general formulation of the problem for a system with a monotonically varying efficiency is discussed. As an example of the technique, the optimal intermittent heating strategy for an electric heat pump with resistive heating booster is derived.  相似文献   
57.
Pretreatment of rats with aminooxyacetic acid (AOAA; 40 mg/kg) raised the concentration of rat brain GABA and inhibited the hyperactivity produced by increasing brain 5-hydroxytryptamine (5-HT) concentration by administration of tranylcypromine and L-tryptophan. The maximum effect was seen 90 min after AOAA injection with smaller effects 30 and 180 min after injection. AOAA did not affect the rate of 5-HT accumulation in the brain, but did inhibit the hyperactivity response which follows injection of the 5-HT agonist 5-methoxy-N,N-dimethyltryptamine, suggesting that post-synaptic 5-HT responses were being inhibited. AOAA also inhibited the locomotor activity which follows administration of tranylcypromine and L-dopa. Blockade of GABA receptors by injection of picrotoxin (2.5 mg/kg) enhanced the dopamine hyperactivity. Since a dopaminergic system has been shown to be involved in the 5-HT hyperactivity syndrome and appears to act post-synaptically to the 5-HT neurones initiating the syndrome it is suggested that inhibition of the 5-HT hyperactivity syndrome may be due to accumulation of GABA distal to the dopaminergic receptors.  相似文献   
58.
When electroshcok therapy was administered to male psychiatric patients without anticonvulsive premedication, serum growth hormone (GH) increased; the increase was not prevented by an infusion of 20% glucose (5 ml per min) 20 min prior to electroshock. Therefore, the GH rise is not caused by muscle exercise during convulsions. Infusing 30 mg of phentolamine 40 min prior to electroshcok inhibited the GH response. Phentolamine's effect shows that the stress-induced GH release that follows electroconvulsive therapy is mediated by alpha-adrenergic neurons.  相似文献   
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This paper reviews the potential impacts of climate change on nitrate concentrations in groundwater of the UK using a Source-Pathway-Receptor framework. Changes in temperature, precipitation quantity and distribution, and atmospheric carbon dioxide concentrations will affect the agricultural nitrate source term through changes in both soil processes and agricultural productivity. Non-agricultural source terms, such as urban areas and atmospheric deposition, are also expected to be affected. The implications for the rate of nitrate leaching to groundwater as a result of these changes are not yet fully understood but predictions suggest that leaching rate may increase under future climate scenarios. Climate change will affect the hydrological cycle with changes to recharge, groundwater levels and resources and flow processes. These changes will impact on concentrations of nitrate in abstracted water and other receptors, such as surface water and groundwater-fed wetlands. The implications for nitrate leaching to groundwater as a result of climate changes are not yet well enough understood to be able to make useful predictions without more site-specific data. The few studies which address the whole cycle show likely changes in nitrate leaching ranging from limited increases to a possible doubling of aquifer concentrations by 2100. These changes may be masked by nitrate reductions from improved agricultural practices, but a range of adaption measures need to be identified. Future impact may also be driven by economic responses to climate change.  相似文献   
60.
This work considers the need for both the amplitude and phase to fully characterize polyvinylidene fluoride (PVDF) membrane hydrophones and presents a comprehensive discussion of the nonlinear acoustic measurements utilized to extract the phase information and the experimental results taken with two widely used PVDF membrane hydrophones up to 100 MHz. A semi-empirical computer model utilized the hyperbolic propagation operator to predict the nonlinear pressure field and provide the complex frequency response of the corresponding source transducer. The PVDF hydrophone phase characteristics, which were obtained directly from the difference between the computer-modeled nonlinear field simulation and the corresponding measured harmonic frequency phase values, agree to within 10% with the phase predictions obtained from receive-transfer-function simulations based on software modeling of the membrane's physical properties. Cable loading effects and membrane hydrophone resonances were distinguished and identified through a series of impedance measurements and receive transfer function simulations on the hydrophones including their hard-wired coaxial cables. The results obtained indicate that the PVDF membrane hydrophone's phase versus frequency plot exhibits oscillations about a monotonically decreasing line. The maxima and minima inflection point slopes occur at the membrane thickness resonances and antiresonances, respectively. A cable resonance was seen at 100 MHz for the hydrophone with a 1-m cable attached, but not seen for the hydrophone with a shorter 0.65-m cable.  相似文献   
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