Psychometric assessment of HIV/STI sexual risk scale among MSM: A Rasch model approach

<p>Abstract</p> <p>Background</p> <p>Little research has assessed the degree of severity and ordering of different types of sexual behaviors for HIV/STI infection in a measurement scale. The purpose of this study was to apply the Rasch model on psychometric assessment of an HIV/STI sexual risk scale among men who have sex with men (MSM).</p> <p>Methods</p> <p>A cross-sectional study using respondent driven sampling was conducted among 351 MSM in Shenzhen, China. The Rasch model was used to examine the psychometric properties of an HIV/STI sexual risk scale including nine types of sexual behaviors.</p> <p>Results</p> <p>The Rasch analysis of the nine items met the unidimensionality and local independence assumption. Although the person reliability was low at 0.35, the item reliability was high at 0.99. The fit statistics provided acceptable infit and outfit values. Item difficulty invariance analysis showed that the item estimates of the risk behavior items were invariant (within error).</p> <p>Conclusions</p> <p>The findings suggest that the Rasch model can be utilized for measuring the level of sexual risk for HIV/STI infection as a single latent construct and for establishing the relative degree of severity of each type of sexual behavior in HIV/STI transmission and acquisition among MSM. The measurement scale provides a useful measurement tool to inform, design and evaluate behavioral interventions for HIV/STI infection among MSM.</p

Combining motivational and volitional approaches to reducing excessive alcohol consumption in pre-drinkers: A theory-based intervention protocol

Background: Pre-drinking refers to the consumption of alcohol at home or a private residence prior to attending a subsequent social event. We present the study protocol of an online theory-based intervention to reduce pre-drinking and related harm in pre-drinking undergraduates, using behavior change techniques targeting the motivational and volitional phases of behaviour. Design: A fully randomized 2 (autonomy support: present vs. absent) x 2 (implementation intention: present vs. absent) between-participants design will be used to ascertain the effectiveness of the intervention in reducing pre-drinking alcohol consumption and alcohol-related harm. Participants will complete a range of theory-based measures prior to being allocated to one of the four experimental conditions. Four weeks later, participants will complete a follow-up questionnaire comprised of theoretical and behavioral measures. Analyses: The main and interactive effects of the intervention components in reducing our primary dependent variables, namely, pre-drinking alcohol consumption and alcohol-related harm at four-week follow-up will be tested. Baseline alcohol consumption and demographic information will be included in the analysis as covariates. Discussion: This online intervention is the first to be developed to reduce pre-drinking alcohol consumption, a behaviour linked to increased risk of alcohol-related harm. The intervention targets motivational and volitional components of the behaviour change process and is therefore likely to lead to greater reductions in pre-drinking alcohol consumption and experience of alcohol-related harm compared to either approach in isolation. If successful, the intervention can be implemented across various contexts and in populations where pre-drinking is prevalent. © 2016 Caudwell et al

Specific Inhibition of Phosphodiesterase-4B Results in Anxiolysis and Facilitates Memory Acquisition

Cognitive dysfunction is a core feature of dementia and a prominent feature in psychiatric disease. As non-redundant regulators of intracellular cAMP gradients, phosphodiesterases (PDE) mediate fundamental aspects of brain function relevant to learning, memory, and higher cognitive functions. Phosphodiesterase-4B (PDE4B) is an important phosphodiesterase in the hippocampal formation, is a major Disrupted in Schizophrenia 1 (DISC1) binding partner and is itself a risk gene for psychiatric illness. To define the effects of specific inhibition of the PDE4B subtype, we generated mice with a catalytic domain mutant form of PDE4B (Y358C) that has decreased ability to hydrolyze cAMP. Structural modelling predictions of decreased function and impaired binding with DISC1 were confirmed in cell assays. Phenotypic characterization of the PDE4BY358C mice revealed facilitated phosphorylation of CREB, decreased binding to DISC1, and upregulation of DISC1 and β-Arrestin in hippocampus and amygdala. In behavioural assays, PDE4BY358C mice displayed decreased anxiety and increased exploration, as well as cognitive enhancement across several tests of learning and memory, consistent with synaptic changes including enhanced long-term potentiation and impaired depotentiation ex vivo. PDE4BY358C mice also demonstrated enhanced neurogenesis. Contextual fear memory, though intact at 24 hours, was decreased at 7 days in PDE4BY358C mice, an effect replicated pharmacologically with a non-selective PDE4 inhibitor, implicating cAMP signalling by PDE4B in a very late phase of consolidation. No effect of the PDE4BY358C mutation was observed in the pre-pulse inhibition and forced swim tests. Our data establish specific inhibition of PDE4B as a promising therapeutic approach for disorders of cognition and anxiety, and a putative target for pathological fear memory

Protein markers and seed size variation in common bean segregating populations

18 páginas, 7 tablas.Selection and random genetic drift are the two main forces affecting allele frequencies in common bean breeding programs. Therefore, knowledge on allele frequency changes attributable to these forces is of fundamental importance for breeders. The changes in frequencies of alleles of biochemical markers were examined in F2 to F7 populations derived from crosses between cultivated Mesoamerican and Andean common bean accessions (Phaseolus vulgaris L.). Biochemical markers included the seed proteins phaseolin, lectin and other seed polypeptides, and six isozymes. The Schaffer’s test detected a high significant linear trend of the 63% of the polymorphic loci studied, meaning that directional selection was acting on those loci. Associations between seed size traits, phaseolin seed-storage protein and isozyme markers were detected based on the comparisons of the progeny genotypic means. In the interracial populations the intermediate form PhaH/T, b6, and Rbcs 98 alleles had a positive effect on seed size. In the inter-gene pool populations, a higher transmission of Mesoamerican alleles in all loci was showed, although the Andean alleles PhaT, Skdh 100 , Rbcs 98 , and Diap 100 showed positive effects on seed weight. Our results suggest that phaseolin and other seed proteins markers are linked to loci affecting seed size. These markers have good potential for improving the results of the selection and should be considered as a strategy for germplasm enhancement and to avoid the reduced performance of the inter-gene pool populations.Research was supported by the projects AGF97-0324 and AGL2005-01268/AGR from the Spanish Government, PGIDIT02RAG40301PR from the Galician Government (Spain), and EU-FEDER Funds. A. M. González thanks her fellowship to Ministry of Education, Culture and Sports of Spain. M. De la Fuente is grateful to the Xunta de Galicia for awarding her a fellowship grant.Peer reviewe

Evaluation of Photopolymerization Kinetics by Means of Transmittance Measurements

Polymeric resins are widely used for dental reconstruction, and most resins use camphorquinone as activator of the polymerization reaction, through the absorption of light at a defined wavelength range (from 400 nm to 460 nm). During the photopolymerization curing, transparency of these resins changes and transmittance variation can be detected by photodiode and bolometer measurements. This change can be used as an index of the reaction rate, and the kinetic parameter k (reaction rate) can be evaluated from transmittance data by means of nonlinear regression. The relation between k and the light intensity impinging on the resin sample can thus be obtained. In the present work, tests were carried out using the resin Enamel Plus HFO GE2. Results reveal the presence of two different polymerization reactions at two different intensity ranges. The obtained k values were used to predict the most suited curing times for different light intensities. The proposed methodology can be applied to different dental reconstruction materials, provided that the material is partially transparent and that its transparency changes during the polymerization reaction