335 research outputs found

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    Schizotypy and Nicotine, Alcohol, and Cannabis Use in a Non-Psychiatric Sample

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    Schizotypy is a multidimensional personality construct that is characterized by perceptual abnormalities, social withdrawal, mild suspiciousness, and odd thinking patterns. This study examined the relationship between four dimensions of self-reported schizotypy and substance use involving nicotine, alcohol, and cannabis, in undergraduate students. Results showed that higher levels of disorganized schizotypy, or odd thinking and behavior, were associated with greater indices of use of all three substances. Furthermore, higher cognitive-perceptual schizotypy was selectively associated with cannabis use. Results confirm findings of recent research that has discovered associations among schizotypy and substance use, highlighting links between behavioral traits and use of nicotine, alcohol, and cannabis. This study is one of the first to examine a wide range of schizotypy domains, and to show selective effects of the disorganized domain of schizotypy

    Molecular characterization of the viaB locus encoding the biosynthetic machinery for Vi capsule formation in Salmonella Typhi

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    The Vi capsular polysaccharide (CPS) of Salmonella enterica serovar Typhi, the cause of human typhoid, is important for infectivity and virulence. The Vi biosynthetic machinery is encoded within the viaB locus composed of 10 genes involved in regulation of expression (tviA), polymer synthesis (tviB-tviE), and cell surface localization of the CPS (vexA-vexE). We cloned the viaB locus from S. Typhi and transposon insertion mutants of individual viaB genes were characterized in Escherichia coli DH5α. Phenotype analysis of viaB mutants revealed that tviB, tviC, tviD and tviE are involved in Vi polymer synthesis. Furthermore, expression of tviB-tviE in E. coli DH5α directed the synthesis of cytoplasmic Vi antigen. Mutants of the ABC transporter genes vexBC and the polysaccharide copolymerase gene vexD accumulated the Vi polymer within the cytoplasm and productivity in these mutants was greatly reduced. In contrast, de novo synthesis of Vi polymer in the export deficient vexA mutant was comparable to wild-type cells, with drastic effects on cell stability. VexE mutant cells exported the Vi, but the CPS was not retained at the cell surface. The secreted polymer of a vexE mutant had different physical characteristics compared to the wild-type Vi

    Confirmation of a Four-Factor Structure of the Schizotypal Personality Questionnaire among Undergraduate Students

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    Objective Although several exploratory and confirmatory factor analyses have supported the initially proposed factor structure of the Schizotypal Personality Questionnaire (SPQ) in which its nine subscales are grouped into cognitive-perceptual, interpersonal, and disorganized domains, others have revealed different latent structures. This study determined the best-fitting factor structure from among five models that have been proposed in the literature, as well as five additional hierarchically related models. Method Undergraduate college students (n=825) completed the SPQ as well as the Perceptual Aberration Scale (PAS) and the Revised Social Anhedonia Scale (SAS). Confirmatory factor analyses involving the nine SPQ subscales were conducted using the Linear Structural Relations Program (LISREL 8.72). Results The best fitting model was a previously described 4-factor model including cognitiveperceptual, paranoid, negative, and disorganized domains. Correlations between the derived SPQ domains and the PAS score ranged r=.26–.39, and correlations between the SPQ domains and the SAS ranged r=.07–.41. Conclusions The present findings support a 4-factor model over the standard 3-factor model that is typically used to derive SPQ subscale scores. The four derived domains are minimally to moderately correlated with other measures of psychosis-proneness

    An examination of the factorial structure of the Schizotypal Personality Questionnaire–Brief (SPQ-B) among undergraduate students

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    Cognitive-perceptual, interpersonal, and disorganized subscales of the Schizotypal Personality Questionnaire–Brief (SPQ-B), reflecting the three commonly used subscales of the full-version SPQ, have been used in a number of studies. However, the factorial validity of SPQB subscales remains to be clarified. Utilizing data from 825 undergraduate students, confirmatory factor analyses involving the 22 items of the SPQ-B were conducted. A significant χ2 difference test favored the 3-factor over the 1-factor model and fit indices for the 3-factor model were generally satisfactory. However, several of the items may index more than one of the hypothesized factors, so the item-factor separation is not sharp. Thus, more research is needed on the factorial validity of the increasingly used SPQ-B subscales
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