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41.
Pharmacological and expectancy effects of 0.3 mg/kg methylphenidate on the behavior and attributions of boys with attention-deficit/hyperactivity disorder were evaluated. In a within-subject, balanced-placebo design, 136 boys received 4 medication-expectancy conditions. Attributions for success and failure on a daily report card were gathered. Assessments took place within the setting of a summer treatment program and were repeated in boys' regular classrooms. Expectancy did not affect the boys' behavior; only active medication improved their behavior. Boys attributed their success to their effort and ability and attributed failure to task difficulty and the pill, regardless of medication and expectancy. Results were generally equivalent across the two settings; where there were differences, beneficial effects of medication were more apparent in the school setting. The findings were unaffected by individual difference factors. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
42.
43.
Intraperitoneal injection of two doses of vinblastine (10 mg/kg and 50 mg/kg) induced a prominent formation of autophagic vacuoles in mouse liver parenchymal cells in 4 h. Clearly recognizable organelles were seen inside these vacuoles. The amount of autophagy was dependent on doses in that autophagosomes almost disappeared within 12 h with the low dose, whereas with the high dose the -ells were filled with residual bodies. Defecation of lysosomal material was ovserved into the sinusoidal lumen 12 h after injection with high dose. The total activities of lysosomal enzymes acid phosphatase, beta-galactosidase, and beta-acetylglucosaminidase did not change in the liver after vinblastine administration. The soluble activities of beta-galactosidase and beta-glucosaminidase were elevated with the high dose 12 h after injection, indicating labilization of the lysosomal membranes. Simultaneously the activities of the three lysosomal enzymes were elevated in the serum. The injurious effect of VBL appeared in light-and electron microscopic levels indicating diffuse necrosis of the liver lobules with the high gose within 12 h, fat accumulation in the cells, accumulation of secretory vesicles containing very low density lipoprotein particles, partial dilatation, vesiculation of endoplasmic reticulum and dilatation of Golgi cisternae. The serum GOT and CPK levels were also elevated  相似文献   
44.
Complex (second-order) channels have been useful in explaining many of the phenomena of perceived texture segregation. These channels contain two stages of linear filtering with an intermediate pointwise nonlinearity. One unanswered question about these hypothetical channels is that of the relationship between the preferred orientations of the two stages of filtering. Is a particular orientation at the second stage equally likely to occur with all orientations at the first stage, or is there a bias in the "mapping" between the two stages' preferred orientations? In this study we consider two possible mappings: that where the orientations at the two stages are identical (called "consistent" here) and that where the orientations at the two stages are perpendicular ("inconsistent"). We explore these mappings using a texture-segregation task with textures composed of arrangements of grating-patch elements. The results imply that, to explain perceived texture segregation, complex channels with a consistent orientation mapping must be either somewhat more prevalent or more effective than those with an inconsistent mapping.  相似文献   
45.
A special experimental technique capable of excluding the influence of differences between sources, substrate crystals, and growth process parameters has been employed to correctly compare the quality of homoepitaxial AlN layers grown by sublimation on Al and N surfaces of the substrate crystal with 〈0001〉 orientation. It has been found that, in most cases, the quality of layers grown on the N surface is somewhat higher; however, no differences have been observed in separate cases. Hence the conclusion follows that the range of growth process parameters is substantially wider for the N side compared with the Al side.  相似文献   
46.
OBJECTIVES: To determine the extent and nature of local ordinances to regulate tobacco sales to minors, the level of enforcement of local and state laws concerning tobacco availability to minors, and sanctions applied as a result of enforcement. DESIGN: Tobacco control ordinances were collected in 1993 from 222 of the 229 cities greater than or equal to 2000 population in Minnesota, United States. In addition a telephone survey with the head of the agency responsible for enforcement of the tobacco ordinances was conducted. MAIN OUTCOME MEASURES: Presence or absence of legislative provisions dealing with youth and tobacco, including licensure of tobacco retailers, sanctions for selling tobacco products to minors, and restrictions on cigarette vending machines, self-service merchandising, and point-of-purchase advertising; and enforcement of these laws (use of inspections and "sting" operations, and sanctions imposed on businesses and minors). RESULTS: Almost 94% of cities required tobacco licences for retailers. However, 57% of the cities specified licences for cigarettes only. Annual licence fees ranged from $10 to $250, with the higher fees adopted in the previous four years. More than 25% of the cities had adopted some kind of restriction on cigarette vending machines, but only six communities had banned self-service cigarette displays. Three cities specified a minimum age for tobacco sales staff. Fewer than 25% of police officials reported having conducted compliance checks with minors or in-store observations of tobacco sales to determine if minors were being sold tobacco during the current year. Police carrying out compliance checks with youth were almost four times as likely to issue citations as those doing in-store observations. More than 90% of police reported enforcement of the law against tobacco purchase or possession by minors, and nearly 40% reported application of penalties against minors. CONCLUSIONS: Almost 75% of the cities have done nothing to change policies or enforcement practices to encourage compliance with tobacco age-of-sale legislation, and only a few of the remaining cities have adopted optimal policies. In addition, officials in Minnesota cities are much more likely to use enforcement strategies against minors who buy tobacco than against merchants who sell tobacco.


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47.
A. A. Wolfson 《Semiconductors》2014,48(11):1532-1534
The proposed study is devoted to investigating the growth conditions of AlN thick layers and bulk crystals in the sublimation sandwich method. For the first time, the dependences of the layer-growth rate on source-substrate clearance are experimentally obtained for this material at two nitrogen-pressure values in the reactor: 0.3 and 0.6 bar. The obtained results point to the fact that the basic mechanism of the transport of components of the source to the substrate is diffusion. The contribution of kinetic effects becomes appreciable at the smallest clearance of 0.3 mm, especially, at a lower nitrogen pressure of 0.3 bar.  相似文献   
48.
Diversity in digestive proteinase activity among insects   总被引:5,自引:0,他引:5  
pH-optimum curves for proteolytic activity from midgut homogenates of 23 species of insects were determined using a radiometric proteinase assay. Optima for digestion of radiolabeled methemoglobin in these insects ranged from pH 3.0 to pH 12.0. Since pH optima vary among the different mechanistic classes of proteinases, these data suggest that there is high diversity in midgut digestive proteinases among various insects.  相似文献   
49.
We have synthesized the first deoxy analogues of myo-inositol 3,4,5, 6-tetrakisphosphate (1) [Ins(3,4,5,6)P4], rac-2-deoxy-myo-inositol 3, 4,5,6-tetrakisphosphate (rac-2), 2-deoxy-myo-inositol 1,4,5, 6-tetrakisphosphate (ent-2), and rac-1-deoxy-myo-inositol 3,4,5, 6-tetrakisphosphate (rac-3). In order to evaluate the binding properties of the three derivatives to the yet unidentified intracellular binding sites for Ins(3,4,5,6)P4, the analogues were converted to membrane-permeant derivatives. Starting with common inositol precursors, various forms of Barton-McCombie deoxygenation and classical protection/deprotection procedures yielded the desired precursors rac-1-O-butyryl-2-deoxy-myo-inositol (rac-12), ent-3-O-butyryl-2-deoxy-myo-inositol (ent-12), and rac-2-O-butyryl-1-deoxy-myo-inositol (rac-19), respectively. Phosphorylation and subsequent deprotection yielded rac-2, ent-2, and rac-3. Alternatively, phosphorylation followed by alkylation with acetoxymethyl bromide gave the membrane-permeant derivatives 1-O-butyryl-2-deoxy-myo-inositol 3,4,5,6-tetrakisphosphate octakis(acetoxymethyl) ester (rac-5), 3-O-butyryl-2-deoxy-myo-inositol 1,4,5,6-tetrakisphosphate octakis(acetoxymethyl) ester (ent-5), and 2-O-butyryl-1-deoxy-myo-inositol 3,4,5,6-tetrakisphosphate octakis(acetoxymethyl) ester (rac-6), respectively. We examined the potency of the membrane-permeant deoxy derivatives in inhibition of calcium-mediated chloride secretion (CaMCS) in intact T84 cells. Compared to the 1,2-di-O-butyryl-myo-inositol 3,4,5, 6-tetrakisphosphate octakis(acetoxymethyl) ester (4), the membrane-permeant derivative of Ins(3,4,5,6)P4 (1), the 2-deoxy derivative (rac-5) exhibited a slightly weaker inhibitory effect, while the enantiomerically pure 2-deoxy-Ins(1,4,5,6)P4 (ent-5) and the 1-deoxy derivative (rac-6) were inactive. As expected, the effect was stereoselective. Thus, the 1-hydroxyl group is apparently essential for binding and the inhibitory effect of Ins(3,4,5,6)P4 on chloride secretion, whereas the 2-hydroxyl group plays a less important role.  相似文献   
50.
Although the problem of increasing the speed of rule-based programs has been studied for a long while, so far the level of parallelism achieved under various parallel processing schemes fails to meet expectations of high performance gains. Most of the work has focused on manipulating existing rule programs to accommodate parallel architectures. However, without changing the inherently sequential algorithms encoded in rule form and without using intrinsic parallel rule languages to exploit parallelism, speedup is severely limited. In this paper we demonstrate that to maximize parallelism, manipulations must take place at the algorithmic level in addition to the program level. However, traditional rule languages are not equipped to easily express parallel algorithms. Thus, an inherently parallel rule language must be devised to enable maximum parallelism. We present our initial specification of such a language, named PARULEL. Preliminary performance results are detailed for one test case program. PARULEL is one part of a larger research effort that considers four key approaches to parallel rule processing: inherently parallel execution semantics; the use of redaction meta-rules to allow programmer control of the set of parallel instantiations; an incremental evaluation algorithm that incorporates, in an efficient manner, updates to the initial set of assumptions; and an algorithm that maps a program to a parallel architecture.  相似文献   
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