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121.
Bimetallic PdRh (with Pd/Rh mole ratio = 2/1) catalysts supported on a mesoporous aluminosilicate have been prepared and three methods of metal incorporation in the support have been compared: direct incorporation into the synthesis gel, impregnation and ion-exchange. Physico-chemical characterisations (nitrogen adsorption–desorption, hydrogen chemisorption, transmission electron microscopy, X-ray photoelectron and extended X-ray absorption fine structure spectroscopies), as well as simulated coking and regeneration tests are described. The dispersion, metal particle size and the formation of bimetallic particles within the material depend on the method of metal incorporation. Direct incorporation and ion-exchange methods lead to co-existence of PdRh intermetallic aggregates and segregated Pd; on the other hand, the impregnation method leads to the formation of very small and well dispersed PdRh alloy particles, with Pd preferentially located on the alloy particle surface.  相似文献   
122.
Two stress and illness models that included the joint mediating effects of health practices and hardiness were tested prospectively over a 2-mo period. 86 undergraduates completed 5 subscales indexing hardiness. Stress, health practices, and illness for the prior month were assessed at this time as well as 1 and 2 mo later. In the 1st model, illness was measured by the severity of physical symptoms. In the 2nd model, it was measured by the number of symptoms reported. In both models, path analyses revealed that stress acted directly to affect illness as well as indirectly by changing health practices. Hardiness also had a direct effect on illness as well as an indirect effect through health practices. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
123.
When a figure moves behind a narrow aperture in an opaque surface, if it is perceived as a figure, its shape will often appear distorted. Under such anorthoscopic conditions, the speed or direction of the object's motion is ambiguous. However, when the observer simultaneously tracks a moving target, a figure is always perceived, and its precise shape is a function of the speed or direction of tracking. The figure is seen as moving with the speed or in the direction of the target. Thus, it is argued that eye movement serves as a cue to the figure's motion, which, in turn, determines its perceived length or orientation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
124.
R. S. Drabman et al (see record 1988-15423-001) investigated children's month of birth in relation to mental health referrals and found that the younger children in a class were disproportionately referred for services. We conducted a replication and extension of the Drabman et al. investigation. Data were collected on children's (N?=?222) cognitive and academic competencies. Results indicated that (a) younger children in a class were disproportionately referred, (b) the referral pattern remained constant across all grades examined, (c) the referral pattern could not be explained by differences in children's competencies, and (d) although the youngest children in the class were referred most frequently, they had the lowest rate of qualification for special services. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
125.
126.
Forty clinically depressed women were randomized to a running, weight lifting, or delayed treatment condition. Self-concept was assessed at baseline, pre-, mid-, and posttreatment for all subjects and at 1, 7, and 12 months for exercise groups. Significant improvements in self-concept were found for exercise groups relative to control groups. No significant differences between exercise groups were found, and improvements were reasonably well-maintained over time. Differential changes on dimensions of self-concept were not demonstrated. These results suggest that both running and weight lifting exercise programs improve self-concept in clinically depressed women. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
127.
Child-care quality and children's social development.   总被引:1,自引:0,他引:1  
This study examined the influence on children's social development of variation in the quality of their child-care environments. The sample consisted of 166 children attending representative child-care centers that varied widely in quality. Possible relations associated with age, child-care experience, and family background were controlled using hierarchical multiple regression. Both global estimates of child-care quality and specific program features, such as director experience, ratios, and verbal interactions, were obtained from observational measures and staff questionnaires. Measures of social development were derived from parent and caregiver ratings of the children. Of greatest importance is the finding that overall quality, caregiver–child verbal interactions, and director experience were each highly predictive of the children's social development in child care. Family background measures were also significantly predictive of several of the social outcomes, whereas child-care experience showed few significant effects. The implications for social policies and future research in child care are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
128.
The positive association between poverty and mental health problems is one of the most well established in all of psychiatric epidemiology. Research has documented consistently that low income and low socioeconomic status are associated with high rates of mental disorder. With the prevalence of poverty itself now on the rise in our country, particularly among women, children and those from minority groups, increased attention must be paid to the mental health risks that accompany poverty. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
129.
120 Ss (who smoked a mean of 30.5 cigarettes/day) were assigned either to intensive behavioral treatment, to nicotine gum in a low-contact treatment, or to the intensive behavioral plus nicotine gum treatment. At each assessment, Ss reported the number of cigarettes smoked in the previous 24 hrs and provided blood samples; assessments were conducted at 0, 3, 12, 26, and 52 wks. Results show that the combined treatment produced higher abstinence rates than the other 2 conditions at all assessments. These differences were significant at 3, 12, and 26 wks, but not at 52 wks. Nicotine dependence was assessed by blood cotinine levels, scores on a dependence scale, and by number of cigarettes smoked at pretreatment. It was found that Ss with high blood cotinines were more likely to be helped by nicotine gum treatment than were less dependent Ss. (4 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
130.
Colorectal cancer (CRC) is a heterogeneous disease with multiple underlying causative genetic mutations. Genetic mutations in the phosphatidylinositol-3 kinase (PI3K) and the mitogen activated protein kinase (MAPK) pathways are frequently implicated in CRC. Targeting the downstream substrate MEK in these mutated tumors stands out as a potential target in CRC. Several selective inhibitors of MEK have entered clinical trial evaluation; however, clinical activity with single MEK inhibitors has been rarely observed and acquired resistance seems to be inevitable. Amplification of the driving oncogene KRAS(13D), which increases signaling through the ERK1/2 pathway, upregulation of the noncanonical wingless/calcium signaling pathway (Wnt), and coexisting PIK3CA mutations have all been implicated with resistance against MEK inhibitor therapy in KRAS mutated CRC. The Wnt pathway and amplification of the oncogene have also been associated with resistance to MEK inhibitors in CRCs harboring BRAF mutations. Thus, dual targeted inhibition of MEK and PI3K pathway effectors (mTOR, PI3K, AKT, IGF-1R or PI3K/mTOR inhibitors) presents a potential strategy to overcome resistance to MEK inhibitor therapy. Many clinical trials are underway to evaluate multiple combinations of these pathway inhibitors in solid tumors.  相似文献   
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