On the structure of the turbulent/non-turbulent interface in a fully developed spatially evolving axisymmetric wake

In this work,we numerically study the structure of the turbulent/nonturbulent(T/NT)interface in a fully developed spatially evolving axisymmetric wake by means of direct numerical simulations.There is a continuous and contorted pure shear layer(PSL)adjacent to the outer edge of the T/NT interface.The local thickness of the PSLδ_(PSL)exhibits a wide range of scales(from the Kolmogorov scale to the Taylor microscale)and the conditional mean thickness<δ_(PSL)>I/η_(c)≈6 withη_(c)being the centerline Kolmogorov scale is the same as the viscous superlayer.In the viscous superlayer,the pure shear motions without rotation are overwhelmingly dominant.It is also demonstrated that the physics of the turbulent sublayer is closely related to the PSL with a large thickness.Another significant finding is that the time averaged area of the rotational regionA R,and the pure shear region<A_(S)>at different streamwise locations scale with the square of the wake-width b_(U)^(2).This study opens an avenue for a better understanding of the structures of the T/NT interface.

Association between the polymorphisms of the VDR gene and kidney stone formation in Guangxi population

Objective:To investigate the relationship between the rs9729,rs11574129,BsmI(rs1544410),TaqI(rs731236)and DdeI(rs3782905)polymorphisms of the vitamin D receptor(VDR)gene and kidney stone formation in a study group from Guangxi.Methods:A hospital-based casecontrol study including 890patients with kidney stone formation and 822age-and sex-matched controls without stone formation was conducted.Five single-nucleotide polymorphisms(SNPs)of the VDR gene were studied using SNPscanTMhighthroughput SNP classification assays.Results:The T allele variant of rs9729significantly increased the risk of kidney stone formation(P=0.021).In particular,a significantly increased risk of kidney stone formation was found in the combined genotypes TG/TT of rs9729compared with the wild GG genotype after covariate adjustment.However,after gender stratification analysis,compared with the wild GG genotype,the GT,TT and GT/TT genotypes of rs9729increased the risk of kidney stone formation in males.Moreover,the GA and GA/GG genotypes of rs11574129 were associated with increased risk of kidney stone formation in males.By contrast,the GC and GC/CC genotypes of DdeI(rs3782905)significantly decreased the risk of kidney stone formation in males.Haplotype analysis suggested that the five-locus polymorphism of VDR was significantly related to kidney stone formation in male participants(P=0.0025).Conclusion:TheT allele variant of the rs9729polymorphism of the VDR gene was significantly related to the risk of kidney stone formation.Gender may affect the association between the rs9729,rs11574129and DdeI polymorphisms of the VDR gene and the risk of kidney stone formation in the Chinese population.