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• Competitive null models may yield false positives from co-expression. • Self-contained null models may yield false positives from bimodal correlations. • Test statistics interact differently with two types of null models. • Supplementary analyses with various configurations support the findings. Correlating transcriptional profiles with imaging-derived phenotypes has the potential to reveal possible molecular architectures associated with cognitive functions, brain development and disorders. Competitive null models built by resampling genes and self-contained null models built by spinning brain regions, along with varying test statistics, have been used to determine the significance of transcriptional associations. However, there has been no systematic evaluation of their performance in imaging transcriptomics analyses. Here, we evaluated the performance of eight different test statistics (mean, mean absolute value, mean squared value, max mean, median, Kolmogorov-Smirnov (KS), Weighted KS and the number of significant correlations) in both competitive null models and self-contained null models. Simulated brain maps (n = 1,000) and gene sets (n = 500) were used to calculate the probability of significance (Psig) for each statistical test. Our results suggested that competitive null models may result in false positive results driven by co-expression within gene sets. Furthermore, we demonstrated that the self-contained null models may fail to account for distribution characteristics (e.g., bimodality) of correlations between all available genes and brain phenotypes, leading to false positives. These two confounding factors interacted differently with test statistics, resulting in varying outcomes. Specifically, the sign-sensitive test statistics (i.e., mean, median, KS, Weighted KS) were influenced by co-expression bias in the competitive null models, while median and sign-insensitive test statistics were sensitive to the bimodality bias in the self-contained null models. Additionally, KS-based statistics produced conservative results in the self-contained null models, which increased the risk of false negatives. Comprehensive supplementary analyses with various configurations, including realistic scenarios, supported the results. These findings suggest utilizing sign-insensitive test statistics such as mean absolute value, max mean in the competitive null models and the mean as the test statistic for the self-contained null models. Additionally, adopting the confounder-matched (e.g., coexpression-matched) null models as an alternative to standard null models can be a viable strategy. Overall, the present study offers insights into the selection of statistical tests for imaging transcriptomics studies, highlighting areas for further investigation and refinement in the evaluation of novel and commonly used tests. [ABSTRACT FROM AUTHOR]

Endometritis is a significant contributor to reduced productivity in yaks in Tibet, China. The Cyt-c/Caspase-3 signaling axis plays a crucial role in the mitochondrial pathway that triggers cell apoptosis due to endogenous factors. In this study, we examined the endometrial epithelial tissue of yaks with endometritis using pathological examination, immunohistochemical analysis, TUNEL staining, qRT-PCR, and Western blot. The results indicated significant changes in the apoptotic factors of the Cyt-c/Caspase-3 signaling axis. The expression levels of Bak1, Bax, Cyt-c, Apaf-1, Caspase-9, and Caspase-3 were significantly increased (P < 0.05), while the expression level of Bcl-2 was significantly decreased. Immunohistochemistry results revealed significant increase in Bak1, Bax, Cyt-c, Apaf-1, Caspase-9, and Caspase-3 expression in the cytoplasm compared to the healthy group, except for Bcl-2, which showed a significant decrease. Pathological section analysis demonstrated that clinical endometritis in yaks led to structural damage, bleeding, congestion, and inflammatory cell infiltration in the endometrial epithelium. Our study findings indicated that clinical endometritis in yaks can modulate apoptosis of endometrial epithelial cells via the Cyt-c/Caspase-3 signaling pathway, resulting in different levels of damage. This research is pioneering in exploring cell apoptosis induced by clinical endometritis in yaks, offering novel insights and potential strategies for the future prevention and treatment of endometritis in yaks. • The occurrence of yak endometritis is accompanied by cell apoptosis. • The Cyt-c/Caspase-3 signaling axis and its related factors play a significant role in the development of yak endometritis. • This study provides new insights into the relationship between endometritis and apoptosis in yak. [ABSTRACT FROM AUTHOR]