Multiaxial Fatigue Life Prediction Based on High-Cycle Uniaxial Fatigue Test of Steel Pipe Weldments with Welding Defects

Hui Liu,Xiu-wen Lv,Shi-chao Chen,Qiang Zhou,Piao Zhou,Wei-lian Qu 한국강구조학회 2023 International Journal of Steel Structures Vol.23 No.1

Welding defects are unavoidable for welded structures, which can lead to fatigue damage even under the random wind load with small amplitude. It is therefore necessary to explore the effect of welding defect on the fatigue properties of welded steel pipes. Three groups of welded steel pipe specimens were designed according to welding defect conditions, i.e. specimens without welding defect (Group I), specimens with incomplete fusion (Group II), and specimens with welding porosity (Group III). Uniaxial tension–compression and torsion high-cycle fatigue tests were carried out. S–N curves of uniaxial tension–compression and torsion tests were obtained by cyclic loading with equal stress amplitude. The test results show that the high-cycle fatigue strength of weldments is obviously lower than that of base metal with the same strength under uniaxial tension–compression and torsion loading. In addition, the welding defects result in a decrease in fatigue strength, while the decrease extent by welding porosity is greater than that by incomplete fusion. Finally, because of the inherent multiaxial loading characteristics of welded structures, the high-cycle multiaxial fatigue life of steel pipe weldments was also predicted by using the modified Wöhler curve method based on the uniaxial fatigue test results. It can be found that when the stress amplitude is constant, the fatigue life of welded steel pipe decreases and the modified Wöhler curves move downward more quickly with the increase of damage parameter defined as the ratio of normal stress amplitude to shear stress amplitude on the critical plane, which means that normal stress amplitude will accelerate the cracks growth and result in faster failure of the weld materials.

Mitochondrial citrate accumulation drives alveolar epithelial cell necroptosis in lipopolysaccharide-induced acute lung injury

Yang Hui-Hui,Jiang Hui-Ling,Tao Jia-Hao,Zhang Chen-Yu,Xiong Jian-Bing,Yang Jin-Tong,Liu Yu-Biao,Zhong Wen-Jing,Guan Xin-Xin,Duan Jia-Xi,Zhang Yan-Feng,Liu Shao-Kun,Jiang Jian-Xin,Zhou Yong,Guan Cha-Xi 생화학분자생물학회 2022 Experimental and molecular medicine Vol.54 No.-

Necroptosis is the major cause of death in alveolar epithelial cells (AECs) during acute lung injury (ALI). Here, we report a previously unrecognized mechanism for necroptosis. We found an accumulation of mitochondrial citrate (citratemt) in lipopolysaccharide (LPS)-treated AECs because of the downregulation of Idh3α and citrate carrier (CIC, also known as Slc25a1). shRNA- or inhibitor–mediated inhibition of Idh3α and Slc25a1 induced citratemt accumulation and necroptosis in vitro. Mice with AEC-specific Idh3α and Slc25a1 deficiency exhibited exacerbated lung injury and AEC necroptosis. Interestingly, the overexpression of Idh3α and Slc25a1 decreased citratemt levels and rescued AECs from necroptosis. Mechanistically, citratemt accumulation induced mitochondrial fission and excessive mitophagy in AECs. Furthermore, citratemt directly interacted with FUN14 domain-containing protein 1 (FUNDC1) and promoted the interaction of FUNDC1 with dynamin-related protein 1 (DRP1), leading to excessive mitophagy-mediated necroptosis and thereby initiating and promoting ALI. Importantly, necroptosis induced by citratemt accumulation was inhibited in FUNDC1-knockout AECs. We show that citratemt accumulation is a novel target for protection against ALI involving necroptosis.

Distinctions Between Clinicopathological Factors and Prognosis of Alpha-fetoprotein Negative and Positive Hepatocelluar Carcinoma Patients

Xu, Jia,Liu, Chang,Zhou, Lei,Tian, Feng,Tai, Ming-Hui,Wei, Ji-Chao,Qu, Kai,Meng, Fan-Di,Zhang, Ling-Qiang,Wang, Zhi-Xin,Zhang, Jing-Yao,Chang, Hu-Lin,Liu, Si-Nan,Xu, Xin-Shen,Song, Yan-Zhou,Liu, Jun,Z Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.2

Serum alpha-fetoprotein (AFP) is a significant marker for clinical diagnosis and prognosis evaluation in hepatocellular carcinoma (HCC) patients. However, some proportion of liver cancer patients are AFP-negative (AFP ${\leq}$20ng/ml). In order to study the differences between clinicopathological factors and prognosis of alpha-fetoprotein negative and positive patients, a total of 114 cases (41 AFP-negative and 73 AFP-positive) were selected for our research. By systematically statistical analysis, the results demonstrated that compared with AFP-negative patients, AFP-positive examples were more likely to feature cirrhosis nodules, non-complete neoplasm capsules, and a poor Edmondson-steiner grade. Furthermore, AFP-negative patients demonstrated a favorable long-term prognosis. By univariate analysis and multivariate analysis with Cox's proportional hazards model, multiple tumors were found to be independent risk factors for worse survival of AFP negative patients; however, less tumor-free margins, multiple tumors and Edmondson-steiner grades III/IV, proved to be independent risk factors leading to a poor prognosis of AFP positive cases. Finally, we can infer that high levels of AFP signify a highly malignant tumor and unfavorable prognosis.

Asp97 is a Crucial Residue Involved in the Ligation of the [Fe4S4] Cluster of IscA from Acidithiobacillus ferrooxidans

( Hui Dan Jiang ),( Xiao Jian Zhang ),( Chen Bing Ai ),( Yuan Dong Liu ),( Jian She Liu ),( Guan Zhou Qiu ),( Jia Zeng ) 한국미생물 · 생명공학회 2008 Journal of microbiology and biotechnology Vol.18 No.6

One simple, rapid and economical method for ploidy detection of Trichogramma dendrolimi Matsumura (Hymenoptera Trichogrammatidae)

Liu Quan-quan,Zhang Chen,Zhou Jin-cheng,Dong Qian-jin,Huo Liang-xiao,Dong Hui 한국응용곤충학회 2020 Journal of Asia-Pacific Entomology Vol.23 No.2

Ploidy diversity provides valuable scientific information, thus making the detection technique of ploidy important. However, traditional methods of cytological observation and flow cytometry are either laborious or expensive. We here report a simple and rapid, effective and economical quantitative PCR (qPCR) approach to determine the ploidy of a parasitoid species Trichogramma dendrolimi Matsumura, an economically important biocontrol agent. We applied a mitochondrial gene cytochrome oxidase (COI) and a nuclear gene forkhead to evaluate the mitochondrial number per nuclear copy in a thelytokous Wolbachia-infected strain of T. dendrolimi and its bisexual uninfected counterparts. The 2 −ΔCq values calculated from C q values which resulted from qPCR experiments were significantly larger in haploid males than that in diploid females. Haploid males possessed about 2.69 times mitochondrial number per nuclear copy as diploid females. Not a single significant difference was found between diploid females from thelytokous and bisexual strains. Based on the differences in relative mitochondrial content, we were allowed to distinguish between haploid males and diploid females. Moreover, the number of mitochondria significantly decreased with higher ploidy level but was not affected by Wolbachiainfection. Our study supplied an available tool to investigate the ploidy diversity in sex determination of T. dendrolimi and thelytokous manipulation of Wolbachia, which is the crucial step to further study their underlying mechanisms. This will in turn contribute to the biocontrol efficiency by enhancing the female production and hence the parasitism rate.

Long-term Prognosis in Hepatocellular Carcinoma Patients after Hepatectomy

Zhou, Lei,Liu, Chang,Meng, Fan-Di,Qu, Kai,Tian, Feng,Tai, Ming-Hui,Wei, Ji-Chao,Wang, Rui-Tao Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.2

Background: The hepatocellular carcinoma is very common in China. Our aim in this report was to investigate clinical and pathological factors based on the current decade data that could influence prognosis of HCC patients after hepatectomy. Methods: Between 2002 and 2009, all patients undergoing hepatectomy for HCC were followed up and reviewed retrospectively. Prognostic factors were studied by univariate and multivariate analysis, with Kaplan-Meier and Cox multivariate survival analyses. Results: Complete clinicopathologic and follow-up data were available for 114 patients. The estimated cumulative survival rates at 1, 3, and 5 yr were 84.6%, 60.2% and 51.8%, respectively. On univariate analysis, key prognostic factors were AFP level, GGT level, tumor size, number of tumors, portal vein invasion, liver cirrhosis status and TNM stage. In the multivariate analysis, tumor size, GGT level, liver cirrhosis status and portal vein invasion were significantly associated with patients' prognosis. Conclusion: Through follow-up of a relatively large cohort of Chinese patients, tumor size, GGT level, liver cirrhosis status, portal vein invasion were revealed as important factors for long-term survival after hepatectomy. Early diagnosis for tumor and the improvement of liver function before surgery are important ways to improve the prognosis.

The impacts of LPCVD wrap-around on the performance of n-type tunnel oxide passivated contact c-Si solar cell

Zhou Ying,Tao Ke,Liu Aimin,Rui Jia,Bao Jianhui,Sun Yufeng,Yang Sanchuan,Wang Qinqin,Zhang Qiang,Yang Songbo,Cao Yujia,Qu Hui 한국물리학회 2020 Current Applied Physics Vol.20 No.7

In this paper, Tunnel Oxide Passivated Contact (TOPCon) silicon solar cells with the industrial area (244.32 cm2) are fabricated on N-type silicon substrates. Both the ultra-thin tunnel oxide layer and phosphorus doped polycrystalline silicon (polysilicon) thin film are prepared by the LPCVD system. The wrap-around of polysilicon is observed on the surface of borosilicate glass (BSG). The polysilicon wrap-around can form a leakage current path, thus degrades the shunt resistance of solar cells, and leads to the degradation of solar cell efficiency. Different methods are adopted to treat the polysilicon wrap-around and improve shunt resistance of solar cells. The experimental results indicate that a chemical etching method can effectively solve the problem of polysilicon wrap-around and improve the performance of solar cells. Finally, a conversion efficiency of 22.81% has been achieved by our bifacial TOPCon solar cells, with Voc of 702.6 mV, Jsc of 39.78 mA/cm2 and FF of 81.62%.

HGFK1 is Associated with a Better Prognostis and Reverses Inhibition by Gefitinib in NSCLC Cases

Zhou, Xiao-Hui,Tang, Li-Na,Yue, Lu,Min, Da-Liu,Yang, Yi,Huang, Jian-An,Shen, Zan Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.4

Purpose: Non small cell lung cancer (NSCLC) is the leading worldwide source of cancer-related deaths. Although some drugs targeting EGFR mutations have been developed, most advanced cases are still incurable. New targets for anticancer drugs are demanded. The kringle 1 domain of hepatocellular growth factor alpha chain (HGFK1) is a potent anti-angiogenesis factor. It has also emerged as a potential anticancer factor in hepatocellular carcinoma (HCC). The expression of HGFK1 protein in patients with NSCLC has not been reported to date. Method: Here, we assessed HGFK1 expression by Western blotting in 103 cases with advanced NSCLC to investigate the impact of HGFK1 on survival. Results: Results revealed 33 (30.1%) patients were classified as high expressors, this being significantly associated with less remote metastasis (P = 0.002) but not with lymph node metastasis (P = 0.062). There was also a significant association between HGFK1 expression and tumor size (P = 0.025) as well as clinical stage (P = 0.012). Kaplan-Meier survival analysis showed that both overall survival (OS) and progression free survival (PFS) of patients with HGFK1 expression were longer than those of patients without HGFK1 expression (P = 0.004 and P = 0.001 respectively). HGFK1 reversed gefitinib inhibition in the resistent NSCLC cell line A431/GR but did not inhibit the proliferation of NSCLC cells A431 and A431/GR directly. Reversion of gefitinib inhibition in A431/GR cells by HGFK1 was related to decreased phosphorylation of ERK and STAT5. Conclusions: HGFK1 may be a useful prognostic factor of advanced NSCLC patients and a potential drug for gefitinib resistant patients.

The role of ginsenoside Rb1, a potential natural glutathione reductase agonist, in preventing oxidative stress-induced apoptosis of H9C2 cells

Hui-Jie Fan,Zhang-Bin Tan,Yu-Ting Wu,Xiao-Reng Feng,Yi-Ming Bi,Ling-Peng Xie,Wen-Tong Zhang,Zhi Ming,Bin Liu,Ying-Chun Zhou 고려인삼학회 2020 Journal of Ginseng Research Vol.44 No.2

Background: Oxidative stress-induced cardiomyocytes apoptosis is a key pathological process inischemic heart disease. Glutathione reductase (GR) reduces glutathione disulfide to glutathione (GSH) toalleviate oxidative stress. Ginsenoside Rb1 (GRb1) prevents the apoptosis of cardiomyocytes; however,the role of GR in this process is unclear. Therefore, the effects of GRb1 on GR were investigated in thisstudy. Methods: The antiapoptotic effects of GRb1 were evaluated in H9C2 cells by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, annexin V/propidium iodide staining, and Western blotting. Theantioxidative effects were measured by a reactive oxygen species assay, and GSH levels and GR activitywere examined in the presence and absence of the GR inhibitor 1,3-bis-(2-chloroethyl)-1-nitrosourea. Molecular docking and molecular dynamics simulations were used to investigate the binding of GRb1 toGR. The direct influence of GRb1 on GR was confirmed by recombinant human GR protein. Results: GRb1 pretreatment caused dose-dependent inhibition of tert-butyl hydroperoxide-induced cellapoptosis, at a level comparable to that of the positive control N-acetyl-L-cysteine. The binding energybetween GRb1 and GR was positive ( 6.426 kcal/mol), and the binding was stable. GRb1 significantlyreduced reactive oxygen species production and increased GSH level and GR activity without altering GRprotein expression in H9C2 cells. Moreover, GRb1 enhanced the recombinant human GR protein activityin vitro, with a half-maximal effective concentration of z2.317 mM. Conversely, 1,3-bis-(2-chloroethyl)-1-nitrosourea co-treatment significantly abolished the GRb1’s apoptotic and antioxidative effects of GRb1in H9C2 cells. Conclusion: GRb1 is a potential natural GR agonist that protects against oxidative stresseinducedapoptosis of H9C2 cells.

Involvement of Orai1 in tunicamycin-induced endothelial dysfunction

Hui Yang,Yumei Xue,Sujuan Kuang,Mengzhen Zhang,Jinghui Chen,Lin Liu,Zhixin Shan,Qiuxiong Lin,Xiaohong Li,Min Yang,Hui Zhou,Fang Rao,Chunyu Deng 대한약리학회 2019 The Korean Journal of Physiology & Pharmacology Vol.23 No.2

Endoplasmic reticulum (ER) stress is mediated by disturbance of Ca2+ homeostasis. The store-operated calcium (SOC) channel is the primary Ca2+ channel in non-excitable cells, but its participation in agent-induced ER stress is not clear. In this study, the effects of tunicamycin on Ca2+ influx in human umbilical vein endothelial cells (HUVECs) were observed with the fluorescent probe Fluo-4 AM. The effect of tunicamycin on the expression of the unfolded protein response (UPR)-related proteins BiP and CHOP was assayed by western blotting with or without inhibition of Orai1. Tunicamycin induced endothelial dysfunction by activating ER stress. Orai1 expression and the influx of extracellular Ca2+ in HUVECs were both upregulated during ER stress. The SOC channel inhibitor SKF96365 reversed tunicamycin-induced endothelial cell dysfunction by inhibiting ER stress. Regulation of tunicamycin-induced ER stress by Orai1 indicates that modification of Orai1 activity may have therapeutic value for conditions with ER stress-induced endothelial dysfunction.