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61.
62.
Some unique predictions of a dual-process priming model of morphine analgesic tolerance were tested. Two experiments in which morphine injections during a tolerance acquisition phase were accompanied by nociceptive testing on a hot plate, confirmed the predictions that tolerance acquisition, retention, and environment-specificity would be augmented under signaled drug conditions when low doses or long interdose intervals (IDIs) were used but not when high doses or short IDIs were used. The implications for current alternative theories of morphine tolerance are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
63.
Haemolytic anaemia as a complication of acute hepatitis has been reported in up to 23% of patients. However, the incidence may rise up to 70-87% in patients who have glucose-6-phosphate dehydrogenase (G6PD) deficiency. Massive intravascular haemolysis with renal failure, hepatic encephalopathy and even death have been reported. In our retrospective study of patients with acute viral hepatitis, the overall incidence of acute haemolysis was 4% (17/434). Only 53% (9/17) of them had G6PD deficiency. Patients with acute haemolysis had a significantly higher peak bilirubin level and required more prolonged hospitalization. Since hepatitis A virus vaccination, unlike hepatitis B virus vaccination, is not yet recommended for routine immunization, we suggest subjects who are G6PD-deficient should be vaccinated against hepatitis A. In endemic areas of hepatitis A virus infection, universal immunization remains the definitive answer. 相似文献
64.
65.
Yang C.-C. Chen J.J.-Y. Chau H.L. 《IEEE transactions on pattern analysis and machine intelligence》1989,15(6):760-770
Two algorithms for constructing minimal deduction graphs (MDG) for inferring rules and facts in an extended version of the Horn clause logic are described. A deduction graph (DG) is minimal if the number of arcs in the graph is minimized. Horn clauses (HC) are extended to Horn formulas (HF), such that the head or the body of an HF can be a conjunction of positive literals or a disjunction of the bodies of some rule instances, respectively. Each algorithm constructs an MDG from its source to its sink, whose arcs infer the HF `if source then sink'. The construction of an MDG is based on a sound and complete set of inference rules of reflexivity, transitivity, and conjunction for HFs which proceeds by expanding a tree rooted at its sink until its source has a successful backtracking to the root. Then the MDG is extracted from the tree. The nodes being expanded in such a tree are classified into seven types, which are assigned by different priorities for their growing into subtrees or for their pruning to reduce the tree space 相似文献
66.
By applying the new boundary integral formulation proposed recently by Chau and Wang (1997) for two-dimensional elastic bodies
containing cracks and holes, a new boundary element method for calculating the interaction between cracks and holes is presented
in this paper. Singular interpolation functions of order r-1/2 (where r is the distance measured from the crack tip) are introduced for the discretization of the crack near the crack tips,
such that stress singularity can be modeled appropriately. A nice feature for our implementation is that singular integrands
involved at the element level are integrated analytically. For each of the hole boundaries, an additional unknown constant
is introduced such that the displacement compatibility condition can be satisfied exactly by the complex boundary function
H(t), which is a combination of the traction and displacement density. Another nice feature of the present formulation is
that the stress intensity factors (both K_I and K_II) at crack tips are expressed in terms of the nodal unknown of H(t) exactly, and no extrapolation of numerical data is required.
To demonstrate the accuracy of the present boundary element method, various crack problems are considered: (i) the Griffith
crack problem, (ii) the interaction problem between a circular hole and a straight crack subject to both far field tension
and compression, and (iii) the interaction problem between a circular hole and a kinked crack subject to far field uniaxial
tension. Excellent agreement with existing results is observed for the first two problems and also for the last problem if
the crack-hole interaction is negligible.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
67.
In this paper, a joint spectrum sensing and accessing optimization framework for a multiuser cognitive network is proposed to significantly improve spectrum efficiency. For such a cognitive network, there are two important and limited resources that should be distributed in a comprehensive manner, namely feedback bits and time duration. First, regarding the feedback bits, there are two components: sensing component (used to convey various users' sensing results) and accessing component (used to feedback channel state information). A large sensing component can support more users to perform cooperative sensing, which results in high sensing precision. However, a large accessing component is preferred as well, as it has a direct impact on the performance in the multiuser cognitive network when multi‐antenna technique, such as zero‐forcing beamforming, is utilized. Second, the tradeoff of sensing and accessing duration in a transmission interval needs to be determined, so that the sum transmission rate is optimized while satisfying the interference constraint. In addition, the aforementioned two resources are interrelated and inversive under some conditions. Specifically, sensing time can be saved by utilizing more sensing feedback bits for a given performance objective. Hence, the resources should be allocation in a jointly manner. Based on the joint optimization framework and the intrinsic relationship between the two resources, we propose two joint resource allocation schemes by maximizing the average sum transmission rate in a multiuser multi‐antenna cognitive network. Simulation results show that, by adopting the joint resource allocation schemes, obvious performance gain can be obtained over the traditional fixed strategies.Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
68.
Dr. Ahmad H. Al‐Mestarihi Dr. Atefeh Garzan Josephine M. Kim Dr. Sylvie Garneau‐Tsodikova 《Chembiochem : a European journal of chemical biology》2015,16(9):1307-1313
Naturally produced pyrrolamides, such as congocidine, are nonribosomal peptides that bind to the minor groove of DNA. Efforts to delineate the biosynthetic machinery responsible for their assembly have mainly employed genetic methods, and the enzymes responsible for their biosynthesis remain largely uncharacterized. We report the biochemical characterization of four proteins involved in congocidine formation: the adenylation‐thiolation (A–T) di‐domain Cgc18(1–610), its MbtH‐like partner SAMR0548, the AMP‐binding enzyme Cgc3*, and the T domain Cgc19. We assayed the ATP‐dependent activation of various commercially available and chemically synthesized compounds with Cgc18(1–610) and Cgc3*. We report the revised substrate specificities of Cgc18(1–610) and Cgc3*, and loading of 4‐acetamidopyrrole‐2‐carboxylic acid onto Cgc19. Based on these biochemical studies, we suggest a revised congocidine biosynthetic pathway. 相似文献
69.
As the number and complexities of green building developments are mainly driven by market demands, understanding of end-user behaviors towards their development eventually should play a crucial role on determining their successes. However, very few studies have been attempted to explore end-user behaviors towards green building development. This study successfully applied discrete choice experiments to reveal whether residents with green experience will have different preference and willingness-to-pay values for enhancements on various aspects of environmental performance in green buildings. Generally, both green and conventional residents had strong preferences and were willing to pay more for improving various aspects of environmental performance in green residential developments. They are found to be willing to pay more for energy conservation, than indoor air quality improvement, noise level reduction, landscape area enlargement, or water conservation. No significant differences are found in the preferences between green and conventional residents for energy conservation, indoor air quality improvement, indoor noise reduction, or water conservation, However, green residents were found to be willing to pay significantly less than the conventional residents for enlarging the landscape area within a residential development, despite it was perceived by green residents as one of the major elements that differentiate a green from a conventional development. 相似文献
70.
Wheatgerm is one of the main by‐products of the wheat milling industry, and is generally used for animal feed or oil production. With wheatgerm containing anywhere up to 14% oil, extraction of this oil via pressing and solvent extraction has had some success. The resulting oil is rich in the essential omega‐6 fatty acids and vitamin E, thus making it a speciality oil. The resulting stabilised de‐fatted wheatgerm has an increased protein content enabling it to be a very viable ingredient within the bakery and cereal industry. 相似文献