Research on the radiation characteristics of aerodynamic noises of a simplified bogie of the high-speed train

This paper built a simplified bogie model including 2 axles, 2 wheel-sets and frames, and it was then installed on the high-speed train to compute the aerodynamic noise. The computational result showed that bogies made the noise of the high-speed train obviously serious, the noise near the bogie increased obviously, and the maximum sound pressure level increased by 1.3dBA. Based on Lighthill acoustic theories, this paper adopted large eddy simulation (LES) and FW-H (Ffowcs Williams-Hawking) acoustic model to compute numerical solution for the aerodynamic noise of the bogie. The aerodynamic flow behavior of the bogie and the distribution of aerodynamic noises in the far field were analyzed. Fluctuating pressure at the surface of the bogie was obtained and then combined with boundary element method (BEM) to study the aerodynamic noise sources and acoustic propagation characteristics of the bogie. Computational results showed that large eddies were in axles and wheel-sets, and axles mainly caused the phenomenon of Karman Vortex Street. When the bogie ran at the speed of 30 m/s, main frequencies were 278 Hz and 556 Hz, and the main frequency of aerodynamic drag was twice that of aerodynamic lift. In the vertical plane, longitudinal plane and lateral plane, the aerodynamic noise of the bogie had the characteristics of dipole noises. The main directions of radiation were 90° and 270°. The maximum sound pressure level was 57.3 dBA. The main direction of propagation for the aerodynamic noise of the bogie was right above and below the bogie rather than the left side and the right side of the bogie. The aerodynamic noise sources of the bogie were mainly at the second end axle and the surface of wheel-sets close to axles

Associations between Aquaglyceroporin Gene Polymorphisms and Risk of Stroke among Patients with Hypertension

Background: Dysregulations ofAQP7andAQP9were found to be related to lipid metabolism abnormality, which had been provento be one of the mechanisms of stroke. However, limited epidemiological studies explore the associations betweenAQP7andAQP9and the risk of stroke among patients with hypertension in China. Aims: We aimed to investigate the associations between genetic variants in AQP7andAQP9and the risk of stroke among patients with hypertension, as well as to explore gene-gene andgene-environment interactions. Methods: Baseline blood samples were drawn from 211 cases with stroke and 633 matched controls. Genomic DNA was extracted by a commercially available kit. Genotyping of 5 single nucleotide polymorphisms (SNPs) in AQP7 (rs2989924, rs3758269, and rs2542743) and AQP9 (rs57139208, rs16939881) was performed by the polymerase chain reaction assay with TaqMan probes. Results: Participants with the rs2989924 GG genotype were found to be with a 1.74-fold increased risk of stroke compared to those with the AA+AG genotype, and this association remained significant after adjustment for potential confounders (odds ratio (OR): 1.74, 95% confidence interval (CI): 1.23-2.46). The SNP rs3758269 CC+TT genotype was found to be with a 33% decreased risk of stroke after multivariate adjustment (OR: 0.67, 95% CI: 0.45-0.99) compared to the rs3758269 CC genotype. The significantly increased risk of stroke was prominent among males, patients aged 60 or above, and participants who were overweight and with a harbored genetic variant in SNP rs2989924. After adjusting potential confounders, the SNP rs3758269 CT+TT genotype was found to be significantly associated with a decreased risk of stroke compared to the CC genotype among participants younger than 60 years old or overweight. No statistically significant associations were observed between genotypes of rs2542743, rs57139208, or rs16939881 with the risk of stroke. Neither interactions nor linkage disequilibrium had been observed in this study. Conclusions: This study suggests that SNPs rs2989924 and rs3758269 are associated with the risk of stroke among patients with hypertension, while there were no statistically significant associations between rs2542743, rs57139208, and rs16939881 and the risk of stroke being observed

Transcriptional profiling of CcpE-regulated genes in Staphylococcus aureus

AbstractThe transcriptional regulator CcpE is an important citrate-sensing regulator that modulates metabolic state, virulence factor expression, and bacterial virulence of Staphylococcus aureus (Ding et al., 2014 [1]). In this article, we report detailed methods for genome-wide transcriptional profiling of CcpE-regulated genes generated for the research article “Metabolic sensor governing bacterial virulence in Staphylococcus aureus” (Ding et al., 2014 [1]). All transcriptional profiling data was deposited to Gene Expression Omnibus (GEO) database under accession number GSE57260