Summary
We propose a general new method, the conditional permutation test, for testing the conditional independence of variables X and Y given a potentially high dimensional random vector Z that may contain confounding factors. The test permutes entries of X non‐uniformly, to respect the existing dependence between X and Z and thus to account for the presence of these confounders. Like the conditional randomization test of Candès and co‐workers in 2018, our test relies on the availability of an approximation to the distribution of X|Z—whereas their test uses this estimate to draw new X‐values, for our test we use this approximation to design an appropriate non‐uniform distribution on permutations of the X‐values already seen in the true data. We provide an efficient Markov chain Monte Carlo sampler for the implementation of our method and establish bounds on the type I error in terms of the error in the approximation of the conditional distribution of X|Z, finding that, for the worst‐case test statistic, the inflation in type I error of the conditional permutation test is no larger than that of the conditional randomization test. We validate these theoretical results with experiments on simulated data and on the Capital Bikeshare data set.
Vitiligo is a common depigmentary skin disease that may follow a pattern of multifactorial inheritance. The essential factors of its immunopathogenesis is thought to be the selective destruction of melanocytes. As a new class of microregulators of gene expression, miRNA have been reported to play vital roles in autoimmune diseases, metabolic diseases and cancer. This study sought to characterize the different miRNA expression pattern in the peripheral blood mononuclear cells (PBMC) of patients with non-segmental vitiligo (NSV) and healthy individuals and to examine their direct responses to thymosin α1 (Tα1) treatment. The miRNA expression profile in the PBMC of patients with NSV was analyzed using Exiqon's miRCURY LNA microRNA Array. The differentially expressed miRNA were validated by real-time quantitative polymerase chain reaction. We found that the expression levels of miR-224-3p and miR-4712-3p were upregulated, and miR-3940-5p was downregulated in the PBMC. The common clinical immune modulator Tα1 changed the miRNA expression profile. Our analysis showed that differentially expressed miRNA were associated with the mechanism of immune imbalance of vitiligo and that Tα1 could play an important role in changing the expression of these miRNA in the PBMC of patients with NSV. This study provided further evidence that miRNA may serve as novel drug targets for vitiligo therapeutic evaluation.
Charge recombination dynamics in intrinsic perovskite film and in meso-superstructured perovskite solar cells have been systematically studied, which are found to be mediated by the energetic distribution of intra-gap trap states as described by the trap-limited recombination theory. Besides, the passivation effect of the hole-transport material on trap states is discussed.
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