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991.
Patients with schizophrenia typically demonstrate impairments on semantic and letter fluency tasks but it is possible that these tests demand subtly different cognitive processing: a lexical search based on phonology or orthography or a semantic search based on organization of semantic networks by dimension or attribute. Differences in the performance between these two tasks may imply whether deficits involve difficulties in accessing or traversing connectivities in the semantic system, as opposed to those based on linguistic units. In this meta-analysis, we reviewed 13 studies (N=915) in an attempt to clarify whether schizophrenic patients are in fact differentially impaired in semantic fluency. Results from analyses indicated that schizophrenic patients are disproportionately deficient in category fluency (d=1.23 for semantic and 1.01 for letter fluency with minimal overlap of confidence intervals of weighted d's) suggesting that compromises the semantic system may be present in schizophrenia and perhaps play a role in the symptomatic anomalies exhibited in this patient population. 相似文献
992.
Under natural viewing conditions primates make frequent exploratory eye movements across complex scenes. We recorded neural activity of 62 cells in visual areas V1, V2 and V4 in an awake behaving monkey that freely viewed natural images. About half of the cells studied showed a modulation in firing rate following some of the eye movements made during free viewing, though the proportions showing a discernible modulation varied across areas. These cells were also examined under controlled viewing conditions in which gratings or natural image patches were flashed in and around the classical receptive field while the animal performed a fixation task. Activity rates were generally highest with flashed gratings and lowest during free viewing. Flashed natural image patches evoked responses between these two extremes, and the responses were higher when the patches were confined to the classical receptive field than when they extended into the non-classical surround. Thus the reduction of activity during free viewing relative to that obtained with flashed gratings is partly attributable to natural images being less effective stimuli and partly to suppressive spatio-temporal neural mechanisms that are important during natural vision. 相似文献
993.
This study was undertaken to determine when U.S. children begin to self-handicap, that is, to reduce preparation effort before evaluations rather than applying themselves to do their best. The personal variables examined for their impact on practice behavior were gender, grade level, and self-esteem. The situational variables were time of the self-esteem test (before or after the evaluation task) and importance of the evaluation task. The results showed that (a) the 6th-grade boys were more likely than the 6th-grade girls to self-handicap, (b) the 3rd-grade children were not as affected as the 6th-grade children by the self-evaluation implications of performance evaluations, (c) self-handicapping by low-self-esteem and high-self-esteem 6th graders depended on recent experiences, and (d) the self-affirming experience of a self-esteem test reduced the motivation to self-handicap among high-self-esteem 6th-grade boys. 相似文献
994.
HG Raj RK Sharma BS Garg VS Parmar SC Jain S Goel YK Tyagi A Singh CE Olsen J Wengel 《Canadian Metallurgical Quarterly》1998,6(11):2205-2212
7,8-Dihydroxy-4-methylcoumarin (DHMC) and 7,8-diacetoxy-4-methylcoumarin (DAMC) have been reported to effectively inhibit in-vivo lipid peroxidation in rat tissues induced by CCl4 and paraquat. DHMC was found to readily impart green colour to the lipid peroxidation incubation mixture containing ADP and Fe3+, whereas DAMC formed green complex only upon incubation with liver microsomes, confirming our earlier observation that liver microsomal deacetylase hydrolyses DAMC to DHMC. Sensitive pH metric technique revealed the formation of ADP-Fe-DHMC ternary complex with highest stability, while Fe-DHMC and ADP-DHMC had negligible stabilities concluding that ADP-perferryl ion formation is prevented by DHMC resulting in the production of stable ternary mixed ligand complex (ADP-Fe-DHMC), thereby inhibiting the formation of O2-, and eventually other reactive oxygen species (ROS) responsible for membrane lipid peroxidation. 相似文献
995.
The renal handling of ofloxacin in rats which were given ofloxacin either alone or in combination with probenecid or cimetidine was studied. In the presence of cimetidine or probenecid, ofloxacin's total and renal clearances were reduced and its half-life was prolonged. This suggests that ofloxacin is secreted by both the anionic and cationic transport systems. 相似文献
996.
T van der Poll PM Jansen KJ Van Zee CE Hack HA Oldenburg H Loetscher W Lesslauer SF Lowry LL Moldawer 《Canadian Metallurgical Quarterly》1997,176(1):296-299
Baboons (Papio anubis) receiving a lethal intravenous infusion with live Escherichia coli were pretreated with either a 55-kDa tumor necrosis factor (TNF) receptor-IgG fusion protein (TNFR55:IgG) (n = 4, 4.6 mg/kg) or placebo (n = 4). Neutralization of TNF activity in TNFR55:IgG-treated animals was associated with a complete prevention of mortality and a strong attenuation of coagulation activation as reflected by the plasma concentrations of thrombin-antithrombin III complexes (P < .05). Activation of fibrinolysis was not influenced by TNFR55:IgG (plasma tissue-type plasminogen activator and plasmin-alpha2-antiplasmin complexes), whereas TNFR55:IgG did inhibit the release of plasminogen activator inhibitor type I (P < .05). Furthermore, TNFR55:IgG inhibited neutrophil degranulation (plasma levels of elastase-alpha1-antitrypsin complexes, P < .05) and modestly reduced release of secretory phospholipase A2. These data suggest that endogenous TNF contributes to activation of coagulation, but not to stimulation of fibrinolysis, during severe bacteremia. 相似文献
997.
We report a simple method for a quick and efficient localization of thermal shock cracks as narrow as 1 micron or less, using Environmental Scanning Electron Microscopy (ESEM). The non-destructive character of the technique is exploited in order to observe relevant fractographic features of the crack pattern. 相似文献
998.
Forty Aspergillus japonicus and A. aculeatus strains, most of them wild-type isolates, were examined using various molecular and phenotypic techniques. The rDNAs proved to be invariable (even strains of the species A. aculeatus exhibited the same restriction profile), while the strains could be classified into seven different mtDNA RFLP groups. Hybridisation data suggest that six of these mtDNA types have certain common restriction sites, while mtDNA type 7, which was exhibited by some A. aculeatus strains, probably has quite different mtDNA organisation and their size was smallest among the strains studied. The RAPD technique and isoenzyme analysis revealed some variabilities within these RFLP groups and strain specific features could also be recognised. Carbon source assimilation spectra were found to be very distinctive for strains of A. japonicus, A. aculeatus and A. niger, providing a useful tool for pre-characterising new wild-type isolates of black Aspergilli. Only a limited correlation was observed between the dendrograms based on genotypic and phenotypic characters. 相似文献
999.
WP Benten M Lieberherr CE Sekeris F Wunderlich 《Canadian Metallurgical Quarterly》1997,407(2):211-214
MalK is the ATP-hydrolyzing subunit of the binding protein-dependent ATP-binding-cassette (ABC) transport system for maltose from Salmonella typhimurium. In a recent hypothesis, Glu64 and Glu94 of MalK were proposed as candidates for 'catalytic carboxylate', common to ATP- and GTP-hydrolyzing proteins [Yoshida and Amano (1995) FEBS Lett. 359, 1-5]. Substitution of both residues and, additionally, Glu74 by either glutamine or glycine and valine, respectively, had no deleterious effect on maltose transport. Thus, our data disprove the above notion. 相似文献
1000.
S Müller WG Jardine BW Evans RJ Viëtor CE Snape MC Jarvis 《Journal of the science of food and agriculture》2003,83(13):1289-1292
Broccoli stems can become tough and stringy owing to excessive development of the vascular ring. Thickened cell walls from the vascular ring were isolated and their composition was determined. They were derived principally from anatomically recognisable xylem vessels, fibres and tracheids but contained an assemblage of polysaccharides typical of primary cell walls. Their pectin content was particularly high and they contained only 6% lignin as estimated by solid state 13C NMR spectroscopy. They did not differ markedly in composition from parenchyma cell walls within the same stems. Thus, despite their thickness and anatomical appearance, these cell walls resembled the walls of non‐woody cells in their polymer composition. Copyright © 2003 Society of Chemical Industry 相似文献