Nonlinear dynamics of a two-stage planetary gear system with sliding friction and elastic continuum ring gear

Wei Liu,Kai Shi,Valerii Tupolev,Guangbin Yu,Bing Dai 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.1

In this paper, nonlinear dynamics of two-stage planetary gear (TSPG) system with elastic ring gear and sliding friction are studied to extend previous study. Compared with the present literatures, the majority of previous works modeled ring gear as a rigid body and completely ignored the sliding friction. This study mainly focus on the investigation of the effect of sliding friction and ring’s elasticity on the nonlinear behavior through the previous elastic TSPG model. Time-varying mesh stiffness formulas including sliding friction and nonlinearity backlash are derived to compare the bifurcation diagrams and vibration response. Numerical examples show interesting behaviors for the TSPG model including sliding friction and elastic component in comparison with the lumped parameter model.

Association between Toll-Like Receptor 9 -1237T/C Polymorphism and the Susceptibility of Inflammatory Bowel Diseases: A Meta-Analysis

Bing Xia,Jian Shang,Xiaobing Wang,Wei Wang,Huaqin Pan,Shi Liu,Lixia Li,Liping Chen 연세대학교의과대학 2016 Yonsei medical journal Vol.57 No.1

Purpose: The -1237T/C polymorphism of the Toll-like receptor 9 (TLR9) gene has been implicated in the susceptibility of inflammatorybowel diseases (IBDs), but the results remain conflicting. We further investigated this association via meta-analysis. Materials and Methods: Multiple electronic databases were extensively searched until February, 2015. The strength of associationwas evaluated by calculating the pooled odds ratios (ORs) and 95% confidence intervals (CIs). Results: A total of 2987 cases and 2388 controls from eight studies were analyzed. Overall, association was found between TLR9 -1237T/C polymorphism and the risk of IBDs when all the studies were pooled (recessive model, OR: 1.59, 95% CI: 1.02–2.47, p=0.04; homozygote comparison, OR: 1.62, 95% CI: 1.04–2.52, p=0.03; allele model, OR: 1.13, 95% CI: 1.00–1.27, p=0.05). Stratificationby ethnicity indicated an association between TLR9 -1237T/C polymorphism and IBDs risk in Caucasians (recessive model,OR: 1.59, 95% CI: 1.02–2.47, p=0.04; homozygote comparison, OR: 1.62, 95% CI: 1.04–2.52, p=0.03; allele model, OR: 1.12, 95% CI: 1.00–1.27, p=0.05). When stratified by disease type, significant correlation were only found in the Crohn’s disease subgroup (recessive model, OR: 1.69, 95% CI: 1.05–2.73, p=0.03; homozygote model, OR: 1.74, 95% CI: 1.07–2.82, p=0.02; allele model, OR: 1.15, 95% CI: 1.01–1.32, p=0.04). Conclusion: The present study suggested that the TLR9 -1237T/C polymorphism might act as a risk factor in the development of IBDs, particularly in Caucasians.

Numerical calculation and optimization designs in engine cooling water pump

Li Wei,Wang Chuan,Shi Weidong,Zhao Xiaofan,Yang Yongfei,Pei Bing 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.5

The cavitation damage in the Engine cooling water pump (ECWP) is the key factor that shortens the lifespan of automobile cooling systems, and causes vibration and noise. To improve cavitation performance and external characteristics of ECWP, three optimized models were designed on the basis of WP7 diesel ECWP. The whole flow fields in three models and the prototype pump were numerically simulated, employing the time averaged Navier-Stokes equation, the standard k-ε turbulent model and Zwart-Gerber-Belamri multiphase flow model by ANSYS-CFX software. Pressure distribution, turbulent kinetic energy distribution, bubble volume fraction distribution, external characteristics and cavitation performance of the prototype pump and optimized models were compared and analyzed. The results show that the external characteristics and cavitation performance of the optimized models are significantly better than that in the prototype pump. Through decreasing the inlet blade angle and wrap angle, extending the blade to inlets and extending a certain inclination in the blade, shock loss in blade inlet was reduced and so, the performance of pump will be improved. The flow condition at blade inlet will also be improved greatly, which in turn improves cavitation performance. When reducing the quantity of blades, the excretion coefficient will drop, flow area of blade inlet becomes bigger, but head has a little drop. And the pump optimized by reducing the quantity of blades has the optimal cavitation performance among three optimized models. With the decrease of impeller diameter, the absolute pressure in the critical cavitation point becomes bigger, the inlet bubble volume fraction at the same absolute pressure increases while cavitation performance gets worse. The obtained numerical results were compared with the experimental ones, and the outcome showed the same tendency between the two along with acceptable error.

Baicalin attenuates TNBS-induced colitis in rats by modulating the Th17/Treg paradigm

Ying Zou,Shi-Xue Dai,Hong-Gang Chi,Tao Li,Zhi-Wei He,Jian Wang,Cai-Guo Ye,Guo-Liang Huang,Bing Zhao,Wen-Yang Li,Zheng Wan,Jin-Shan Feng,Xue-Bao Zheng 대한약학회 2015 Archives of Pharmacal Research Vol.38 No.10

Baicalin, a flavonoid, has a wide range ofpharmacological properties, including immunomodulation. The objective of this study was to investigate the effect ofbaicalin on the balance of T helper 17 (Th17) and regulatoryT (Treg) cells in a colitis model. The rat colitis modelwas induced by 2,4,6-trinitrobenzene sulfonic acid(TNBS). Baicalin (10 ml/kg, each) or mesalazine (positivecontrol) was then administered orally for 7 days. Inflammatoryand immunological responses were evaluated bypathology, enzyme-linked immunosorbent assay, real-timepolymerase chain reaction, western blot analysis, and flowcytometry. Our study showed that baicalin not only significantlyattenuated TNBS-induced colitis by reducing thedisease activity index as well as macroscopic and microscopicscores, but it also improved the weight loss andshortening of the colon. Baicalin treatment also induced asignificant decrease in the levels of inflammatory mediators,including the myeloperoxidase activity, the levels oftumor necrosis factor a, IL-1b, and Th1-related cytokinesIL-12 and IFN-c. Furthermore, the beneficial effects ofbaicalin seem to be associated with regulation of the Th17and Treg paradigm. We found that administration ofbaicalin significantly downregulated the number of Th17cells and the levels of Th17-related cytokines (IL-17 andIL-6) and retinoic acid receptor-related orphan receptor ct. In contrast, there was an increase in Treg cells numbers,Treg-related cytokines transforming growth factor-b andIL-10, and forkhead box P3. Our results suggest that theanti-inflammatory effect of baicalin may be linked tomodulation of the balance between Th17 and Treg cells inTNBS-induced ulcerative colitis.

Improved the hydrogen sorption properties of MgH2 by CeMnZr solid solution

Ying Cheng,Wei Zhang,Biqing Shi,Siqi Li,Bing Dong,Yulian Quan,Xianbin Ji 한국화학공학회 2023 Korean Journal of Chemical Engineering Vol.40 No.1

Magnesium hydride (MgH2) is one of the promising solid-state hydrogen storage materials because of its high capacity, abundant resource and excellent reversibility. However, the high dehydrogenation temperatures and sluggish kinetics restrict its practical application. It was found that doping catalysts could significantly improve the hydrogen storage properties of MgH2. The solid solution Ce0.8Mn0.1Zr0.1O2 (denoted as CeMnZr) with abundant oxygen vacancy was synthesized and its catalytic influence on the hydrogen sorption properties of MgH2 have been investigated. CeMnZr modified MgH2 composite showed a reduced initial decomposition temperature, almost 62 K lower than the pristine MgH2. At 473 K, MgH2-CeMnZr composite had an absorption capacity of 4.08 wt% hydrogen within 3,500 s, which was about twice better than the pure MgH2 at same condition. MgH2-CeMnZr sample could desorb 2.56 wt% of H2 within 3,500 s at 573 K compared to low desorption rate and 0.85 wt% H2 by as-milled MgH2. The activation energy (Ea) for CeMnZr codoped MgH2 sample is about 50kJ·mol−1 lower than the milled MgH2. Based on the characteration analysis, the in-situ generated MgO and CeH2.51 species as well as abundant oxygen vacancy is believed to play synergistic catalytic effects in enhancing the hydrogen storage properties of MgH2.

Hookworm Infection: A Neglected Cause of Overt Obscure Gastrointestinal Bleeding

Kun-Yan Wei,Qiong Yan,Bo Tang,Shi-Ming Yang,Peng-Bing Zhang,Ming-Ming Deng,Mu-Han Lu 대한기생충학열대의학회 2017 The Korean Journal of Parasitology Vol.55 No.4

Performance of Hepatitis B Core-Related Antigen Versus Hepatitis B Surface Antigen and Hepatitis B Virus DNA in Predicting HBeAg-positive and HBeAg-negative Chronic Hepatitis

Zhan-qing Zhang,Yan-bing Wang,,Wei Lu,,Dan-ping Liu,,Bi-sheng Shi,,Xiao-nan Zhang,,Dan Huang,,Xiu-fen Li,,Xin-lan Zhou,,Rong-rong Ding, 대한진단검사의학회 2019 Annals of Laboratory Medicine Vol.39 No.1

Background: We examined changes in hepatitis B core-related antigen (HBcrAg) during the four sequential phases of chronic hepatitis B virus (HBV) infection: hepatitis B e antigen (HBeAg)-positive chronic infection (EPCI) and hepatitis (EPCH), followed by HBeAg-negative chronic infection (ENCI) and hepatitis (ENCH). We compared the performance of serum HBcrAg, hepatitis B surface antigen (HBsAg), and HBV DNA in predicting EPCH and ENCH.

Experimental and numerical studies on erosion damage in damping holes on the valve plate of an axial piston pump

Shaogan Ye,Junhui Zhang,Bing Xu,Wei Song,Long Chen,Haiyong Shi,Shiqiang Zhu 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.9

Erosion damage affects the reliability and durability of axial piston pumps. An axial piston pump was tested using endurance life testing method. The phenomenon of erosion damage on the valve plate was observed using a confocal laser scanning microscope, by comparing the surface on the valve plate before and after the endurance life testing. A CFD turbulence model inclusive of the cavitation effects was developed to predict the flow physics. The flow physics in the axial piston pump were presented and analyzed, including the fluid velocities, velocity fields, the total volume fraction fields of gas and vapor, and pressure fields. Two causes of erosion damage were found, the appearances of large amount of vapor, and directly hitting by the jetting flow. The first one is the cause of erosion damage on the surface near the transition region from the inlet port to the outlet port, and the second one is the cause of erosion damage on the surface near the transition region from the outlet port to the inlet port. Besides, the findings show that the fluid velocities closely relate to the area of erosion damage. The study provides insights into the occurrence of erosion damage in axial piston pumps.

Metastasis associated genomic aberrations in stage II rectal cancer

Hong Zhao,Zhi-Zhou Shi,Rui Jiang,Dong-Bing Zhao,Hai-Tao Zhou,Jian-Wei Liang,Xin-Yu Bi,Jian-Jun Zhao,Zhi-Yu Li,Jian-Guo Zhou,Zhen Huang,Ye-Fan Zhang,Jian Wang,Xin Xu,Yan Cai,Ming-Rong Wang,Yu Zhang 한국유전학회 2016 Genes & Genomics Vol.38 No.11

Genomic aberrations of rectal carcinoma, especially DNA copy number changes associated with metastasis were largely unclear. We aim to identify the metastasis associated biomarkers in stage II rectal cancer. Formalin-fixed, paraffin-embedded primary tumor tissues of stage II rectal carcinoma were analyzed by array-based comparative genomic hybridization, and genomic aberrations were identified by Genomic Workbench and SAM software. Copy number changes and mRNA expressions were validated by Real-time PCR in an independent rectal cancer samples. The results showed that the most frequent gains in stage II rectal cancer were at 1q21.2-q23.1, 3p21.31, 11q12.2-q23.3, 12q24.11-q24.31, 12q13.11-q14.1 and losses in 18q11.2-q23, 17q21.33-q22, 13q31.1-q31.3, 21q21.1-q21.3, 8p23.3-p23.1 and 4q22.1-q23. Twenty-two amplifications and five homozygous deletions were also identified. We further found that S100A1 (1q21.3-q23.1), MCM7 (7q22.1) and JUND (19p13.11) were amplified and overexpressed in stage II rectal cancer. Interestingly, the genomic aberrations affected 14 signaling pathways including VEGF signaling pathway and fatty acid metabolism. Most importantly, loss of 13q31.1-q34 and gain of 1q44 were associated with distant metastasis. Our results indicated that these metastasis associated genomic changes may be useful to reveal the pathogenesis of rectal cancer metastasis and identify candidate biomarkers.

DNA methylation and mRNA expression of COL6A3 in antler mesenchyme of female and male reindeer

Jian‑Cheng Zhai,Ruo‑Bing Han,Sheng‑Nan Wang,Qiang‑Hui Wang,Yan‑Ling Xia,Wei‑Shi Liu,Ya‑Jie Yin,He‑Ping Li 한국유전학회 2019 Genes & Genomics Vol.41 No.9

Backgroud Reindeer is the only deer species that both male and female produce antlers, which provides a particularly interesting case in studying the differences between antlers of the two sexes. Alpha 3(VI) Collagen Gene (COL6A3), forms a microfibrillar network associated with the structural integrity and biomechanical properties, has been found to be one of the differentially expressed genes in antler mesenchyme of female and male reindeer. Objective and Methods The promoter sequence of reindeer COL6A3 gene was obtained using the cloning technology and analyzed by the bioinformatics methods. Bisulfite sequencing PCR (BSP) was used to detect the methylation status of the COL6A3 promoter in reindeer antler mesenchyme. Real-time quantitative PCR was used to detect COL6A3 expression in the antler mesenchyme of female and male reindeer. Results Sequence analysis revealed that the reindeer COL6A3 partial promoter sequence was 983 bp including the possible promoter region at + 105 bp to + 155 bp. Homology and phylogenetic analysis indicated that the COL6A3 promoter of reindeer had the closest genetic distance with Bos taurus, Capra hircus and Ovis aries. BSP results indicated that the methylation level of COL6A3 promoter in the female reindeer antler mesenchyme was significantly higher than in the male. Correlating with increased methylation status, we also found that COL6A3 mRNA expression in female reindeer antler mesenchyme was significantly lower than in the male. Conclusion The higher methylation level of the COL6A3 gene in female reindeer antler mesenchyme coincides with decreased COL6A3 mRNA expression, thereby affecting the transposon silencing mechanism and possibly contributing to apparent differences of antlers in female and male reindeer.