Yttria is the best face coat material in the shell mold for the investment casting of γ-TiAl alloys. However, yttria inclusions may occur in the cast products and there is a lack of knowledge about ...the influence of yttria inclusions on the mechanical properties of TiAl. In the present study, the effect of yttria inclusions on room temperature tensile properties of two investment cast TiAl alloys, Ti-45Al-2Mn-2Nb (at%) + 0.08vol% TiB2 and Ti-46 Al-2Nb-2Cr-0.15B (at%), were studied. The results show that tensile failure tends to initiate from yttria inclusions, resulting in reduced plastic strain and ultimate strength. Yttria inclusions differ in location (surface /internal), size, and morphology (agglomerate /whole piece), those with larger sizes or located at the sample surface being more harmful. The tensile properties of inclusion containing TiAl parts can be estimated using the size and location determined by X-ray inspection. The critical size at which inclusions become detrimental to the mechanical properties of TiAl was discussed.
Although hypothesis-driven research has identified several factors associated with psychosis, this one-exposure-to-one-outcome approach fails to embrace the multiplicity of exposures. Systematic ...approaches, similar to agnostic genome-wide analyses, are needed to identify genuine signals.
To systematically investigate nongenetic correlates of psychotic experiences through data-driven agnostic analyses and genetically informed approaches to evaluate associations.
This cohort study analyzed data from the UK Biobank Mental Health Survey from January 1 to June 1, 2021. An exposome-wide association study was performed in 2 equal-sized split discovery and replication data sets. Variables associated with psychotic experiences in the exposome-wide analysis were tested in a multivariable model. For the variables associated with psychotic experiences in the final multivariable model, the single-nucleotide variant-based heritability and genetic overlap with psychotic experiences using linkage disequilibrium score regression were estimated, and mendelian randomization (MR) approaches were applied to test potential causality. The significant associations observed in 1-sample MR analyses were further tested in multiple sensitivity tests, including collider-correction MR, 2-sample MR, and multivariable MR analyses.
After quality control based on a priori criteria, 247 environmental, lifestyle, behavioral, and economic variables.
Psychotic experiences.
The study included 155 247 participants (87 896 57% female; mean SD age, 55.94 7.74 years). In the discovery data set, 162 variables (66%) were associated with psychotic experiences. Of these, 148 (91%) were replicated. The multivariable analysis identified 36 variables that were associated with psychotic experiences. Of these, 28 had significant genetic overlap with psychotic experiences. One-sample MR analyses revealed forward associations with 3 variables and reverse associations with 3. Forward associations with ever having experienced sexual assault and pleiotropy of risk-taking behavior and reverse associations without pleiotropy of experiencing a physically violent crime as well as cannabis use and the reverse association with pleiotropy of worrying too long after embarrassment were confirmed in sensitivity tests. Thus, associations with psychotic experiences were found with both well-studied and unexplored multiple correlated variables. For several variables, the direction of the association was reversed in the final multivariable and MR analyses.
The findings of this study underscore the need for systematic approaches and triangulation of evidence to build a knowledge base from ever-growing observational data to guide population-level prevention strategies for psychosis.
Room temperature tensile ductility of extruded Ti-47Al-1.5Nb-1Cr-1Mn-0.5B (at.%) with different surface topographies was investigated. Tensile specimens were subjected to grinding with sandpaper of ...different grits and electrolytic polishing to achieve different surface topographies. Surface morphology/topography and tensile ductility of different surface preparations were compared. Results show that for ground samples, when the mean amplitude deviation (Ra) exceeds 0.1 μm, initiation of tensile failure transits from the sample interior to surface, and tensile fracture strain decreases linearly with increasing Ra. Electrolytic polishing improves the surface topography of TiAl not only by reducing Ra, but also by modifying the amplitude shape and distribution of the surface, and it therefore increases ductility. The present work suggests that surface amplitude deviation (Ra), skewness (Rsk) and kurtosis (Rku) are appropriate parameters to evaluate the surface topography of intermetallic materials with limited ductility such as TiAl.
The current study was conducted to provide a general guidance for model specifications in polygenic risk score (PRS) analyses of the UK Biobank, such as adjusting for covariates (i.e. age, sex, ...recruitment centers, and genetic batch) and the number of principal components (PCs) that need to be included. To cover behavioral, physical and mental health outcomes, we evaluated three continuous outcomes (BMI, smoking, drinking) and two binary outcomes (Major Depressive Disorder and educational attainment). We applied 3280 (656 per phenotype) different models including different sets of covariates. We evaluated these different model specifications by comparing regression parameters such as R2, coefficients, and P values, as well as ANOVA tests. Findings suggest that only up to three PCs appears to be sufficient for controlling population stratification for most outcomes, whereas including other covariates (particularly age and sex) appears to be more essential for model performance.
Hair color is one of the most recognizable visual traits in European populations and is under strong genetic control. Here we report the results of a genome-wide association study meta-analysis of ...almost 300,000 participants of European descent. We identified 123 autosomal and one X-chromosome loci significantly associated with hair color; all but 13 are novel. Collectively, single-nucleotide polymorphisms associated with hair color within these loci explain 34.6% of red hair, 24.8% of blond hair, and 26.1% of black hair heritability in the study populations. These results confirm the polygenic nature of complex phenotypes and improve our understanding of melanin pigment metabolism in humans.
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