Effect of local wall thinning on ratcheting behavior of pressurized 90° elbow pipe under reversed bending using finite element analysis

Xiaohui Chen,Xu Chen 국제구조공학회 2016 Steel and Composite Structures, An International J Vol.20 No.4

Ratcheting deformation of pressurized Z2CND18.12N stainless steel 90° elbow pipe with local wall thinning subjected to constant internal pressure and reversed bending was studied using finite element analysis. Chen-Jiao-Kim (CJK) kinematic hardening model, which was used to simulate ratcheting behavior of pressurized 90° elbow pipe with local wall thinning at extrados, flanks and intrados, was implemented into finite element software ANSYS. The local wall thinning was located at extrados, flanks and intrados of 90° elbow pipe, whose geometry was rectangular cross-section. The effect of depth, axial length and circumferential angle of local wall thinning at extrados, flanks and intrados on the ratcheting behaviors of 90° elbow pipe were studied in this paper. Threedimensional elastic-plastic analysis with Chen-Jiao-Kim (CJK) kinematic hardening model was carried out to evaluate structural ratcheting behaviors. The results indicated that ratcheting strain was generated mainly along the hoop direction, while axial ratcheting strain was relatively small.

Promoter Analysis of Bombyx mori Nucleopolyhedrovirus Ubiquitin Gene

Xu’ai Lin,Yin Chen,Yongzhu Yi,Jie Yan,Zhifang Zhang 한국미생물학회 2008 The journal of microbiology Vol.46 No.4

The aim of this study was to analyze the characteristics of Bombyx mori nucleopolyhedrovirus (BmNPV) ubiquitin gene promoter and the effects of conserved motifs, such as TAAG, TATA, and CAAT, along with baculovirus enhancer homologous region 3 (hr3), on promoter activity. Ubiquitin gene of BmNPV was expressed during the late phase of virus infection. In the presence of viral factors, significant reduction of promoter activity was observed by deletion of -382 to -124 bp upstream of ATG. The fragment between -187 and -383 bp upstream of ATG, including distal TAAG, CAAT motif, and TATA box, could also drive expression of the reporter gene. The mutation of cis-elements TATA boxes and TAAG motifs significantly decreased the promoter’s activity, while CAAT mutations enhanced promoter activity by 2- or 3-fold, as compared with the native promoter. In the presence of BmNPV, hr3, both located downstream of the reporter gene of the same vector, and separate vector, could significantly enhance transcription activity of ubiquitin promoter as compared to the control. We concluded that BmNPV ubiquitin gene might be regulated by dual sets of promoter elements, where TAAG and TATA box may positively regulate the expression of ubiquitin, while CAAT motif functions as a negative regulator. Viral factor(s) play an important role in the co-activation of hr3 and promoter.

Comparative Analysis of Post-editing Techniques for Chinese-to-English Translation Tasks: A Quasi-Experimental Study

Chen Xu(Chen Xu ),신유선(Yousun Shin) 한국영미어문학회 2023 영미어문학 Vol.- No.149

This study aimed to examine the differences in translation time and quality between human translation (HT), machine translation post-editing (MTPE), and ChatGPT post-editing (ChatGPT PE). A quasi-experimental design was employed, involving 30 junior participants majoring in English from a Chinese university. A translation task consisting of 532 words from Chinese to English was assigned to the three groups and the translation speed and quality were assessed using the Multidimensional Quality Metrics (MQM) and Dynamic Quality Framework (DQF). The results demonstrated that the post-editing technique could produce translation quality comparable to human translation while achieving faster translation speed. It was observed that ChatGPT PE outputs exhibited the highest number of terminology errors but had the fewest accuracy errors, while mean differences in two of accuracy dimensions were observed among the three groups. The utilization of post-editing in language teaching would allow for the integration of machine translation strengths and human expertise, resulting in high-quality translations on par with human translations. To optimize post-editing outcomes, it is crucial to develop and teach error-detection techniques and avoid excessive reliance on AI technology.

Ratcheting behavior of pressurized Z2CND18.12N stainless steel pipe under different control modes

Xu Chen,Xiaohui Chen,Gang Chen,Duomin Li 국제구조공학회 2015 Steel and Composite Structures, An International J Vol.18 No.1

With a quasi-three point bending apparatus, ratcheting deformation is studied experimentally on a pressurized austenitic stainless steel Z2CND18.12N pipe under bending load and vertical displacement control, respectively. The characteristic of ratcheting behavior of straight pipe under both control methods is achieved and compared. The cyclic bending loading and internal pressure influence ratcheting behavior of pressurized straight pipe significantly under loading control and the ratcheting characteristics are also highly associated with the cyclic displacement and internal pressure under displacement control. They all affect not only the saturation of the ratcheting strain but the ratcheting strain rate. In addition, ratcheting simulation is performed by elastic.plastic finite element analysis with ANSYS in which the bilinear model, Chaboche model, Ohno.Wang model and modified Ohno-Wang model are applied. By comparison with the experimental data, it is found that the CJK model gives reasonable simulation. Ratcheting boundaries under two control modes are almost same.

Multi-UAV Distributed Cooperative Detection Based on Consensus

Xia Chen,Xiangmin Chen,Xiaoming Wei,Guangyan Xu 보안공학연구지원센터 2014 International Journal of Control and Automation Vol.7 No.12

This paper presents an analysis method aiming at UAV cooperative detection problem. The UAV detect the target and establish the state information respectively, and send the message to the adjacent friendly aircraft. The friendly aircraft judge if there are repetition between their own information and the message they have received after they receive the message, and re-order the target till the state information of all UAV are same and complete the mission of multi-UAV distributed cooperative detection. The simulation shows that the algorithm presented in this paper could accomplish the cooperative detection mission effective and reasonable.

Analysis of Different Activation Statuses of Human Mammary Epithelial Cells from Young and Old Groups

Feng, Chen-Chen,Chen, Li-Na,Chen, Mei-Jun,Li, Wan,Jia, Xu,Zhou, Yan-Yan,He, Wei-Ming Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.8

Human mammary epithelial cells have different proliferative statuses and demonstrate a close relationship with age and cell proliferation. Research on this topic could help understand the occurrence, progression and prognosis of breast cancer. In this article, using significance analysis of a microarray algorithm, we analyzed gene expression profiles of human mammary epithelial cells of different proliferative statuses and different age groups. The results showed there were significant differences in gene expression in the same proliferation status between elderly and young groups. Three common differentially expressed genes were found to dynamically change with the proliferation status and to be closely related to tumorigenesis. We also found elderly group had less status-related differential genes from actively proliferating status to intermediate status and more statusrelated differential genes from intermediate status than the young group. Finally, functional enrichment analyses allowed evaluation of the detailed roles of these differentially-expressed genes in tumor progression.

Triplet Platinum-based Combination Sequential Chemotherapy Improves Survival Outcome and Quality of Life of Advanced Non-small Cell Lung Cancer Patients

Chen, Li-Kun,Liang, Ying,Yang, Qun-Ying,Xu, Fei,Zhou, Ning-Ning,Xu, Guang-Chuan,Liu, Guo-Zhen,Wei, Wei-Dong Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.5

Background: Maintenance chemotherapy is one strategy pursued in recent years with intent to break through the chemotherapy plateau for advanced non-small cell lung cancer (NSCLC). However, given the toxicity, platinum-based combinations are rarely given for this purpose. We carried out the present prospective study of triplet platinum-based combination sequential chemotherapy in advanced NSCLC to investigate if patients could tolerate and benefit from such intensive treatment. Methods: From Dec 2003 to Dec 2007, 190 stage IIIB and IV NSCLC patients in Sun yat-sen University sequentially received the 3 platinum-based combination (TP-NP-GP) treatment (T: paclitaxol175$mg/m^2$ d1; N: vinorelbine25$mg/m^2$ d1 and 8; G: gemcitabine1$g/m^2$ d1 and 8; P: cisplatin20$mg/m^2$ d1-5; repeated every 3 weeks). Patients were followed up to at least 3 years to obtain survival data. Treatment toxicities and the quality of life (QOL) were assessed during the whole treatment. Results: There were 187 patients evaluable. The TP, NP and GP response rates with sequential use were 42.8% (80/187), 41.1% (65/158) and 28.8% (21/73) respectively. Median survival time was 18.2 months and the 1, 2 and 3 year overall survival (OS) rates were 78.7%, 38.5% and 21.3%. Patients receiving > 6 cycles of chemotherapy had significantly longer OS and TTP (MST 25.3 vs. 14.5 months, TTP 15.1 vs. 9.1 months). The QOL on the whole for the patients was improved after chemotherapy. Conclusions: The sequential chemotherapy strategy with triplet platinum-based combination regimens can improve the survival outcome and the quality of life of advanced non-small cell lung cancer patients.

Asiatic Acid Promotes p21^WAF1/CIP1 Protein Stability through Attenuation of NDR1/2 Dependent Phosphorylation of p21^WAF1/CIP1 in HepG2 Human Hepatoma Cells

Chen, Jin-Yuan,Xu, Qing-Wen,Xu, Hong,Huang, Zong-Hai Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.2

Previous studies have suggested anti-tumor effects of asiatic acid in some human cancer cell lines. This agent is reported to increase the levels of $p21^{WAF1/CIP1}$ in human breast cancer cell lines. However, the molecular mechanisms have not been established. Here we report that asiatic acid up-regulates $p21^{WAF1/CIP1}$ protein expression but not the level of $p21^{WAF1/CIP1}$ mRNA in HepG2 human hepatoma cells. Furthermore, we found that the asiatic acid induced increase of $p21^{WAF1/CIP1}$ protein was associated with decreased phosphorylation (ser-146) of $p21^{WAF1/CIP1}$. Knockdown of NDR1/2 kinase, which directly phosphorylates $p21^{WAF1/CIP1}$ protein at ser-146 and enhances its proteasomal degradation, increased the levels of $p21^{WAF1/CIP1}$ protein and eliminated the regulation of $p21^{WAF1/CIP1}$ stability by asiatic acid. At the same time, the expression of NDR1/2 kinase decreased during treatment with asiatic acid in HepG2 cells. Moreover, asiatic acid inhibited the proliferation of HepG2 cells, this being attenuated by knockdown of $p21^{WAF1/CIP1}$. In conclusion, we propose that asiatic acid inhibits the expression NDR1/2 kinase and promotes the stability of $p21^{WAF1/CIP1}$ protein through attenuating NDR1/2 dependent phosphorylation of $p21^{WAF1/CIP1}$ in HepG2 cells.

Removal of the Glycosylation of Prion Protein Provokes Apoptosis in SF126

Chen, Lan,Yang, Yang,Han, Jun,Zhang, Bao-Yun,Zhao, Lin,Nie, Kai,Wang, Xiao-Fan,Li, Feng,Gao, Chen,Dong, Xiao-Ping,Xu, Cai-Min Korean Society for Biochemistry and Molecular Biol 2007 Journal of biochemistry and molecular biology Vol.40 No.5

Although the function of cellular prion protein (PrP$^C$) and the pathogenesis of prion diseases have been widely described, the mechanisms are not fully clarified. In this study, increases of the portion of non-glycosylated prion protein deposited in the hamster brains infected with scrapie strain 263K were described. To elucidate the pathological role of glycosylation profile of PrP, wild type human PrP (HuPrP) and two genetic engineering generated non-glycosylated PrP mutants (N181Q/N197Q and T183A/T199A) were transiently expressed in human astrocytoma cell line SF126. The results revealed that expressions of non-glycosylated PrP induced significantly more apoptosis cells than that of wild type PrP. It illustrated that Bcl-2 proteins might be involved in the apoptosis pathway of non-glycosylated PrPs. Our data highlights that removal of glycosylation of prion protein provokes cells apoptosis.

Quantitative Assessment of the Association between ABC Polymorphisms and Osteosarcoma Response: a Meta-analysis

Chen, Xu,Jiang, Min,Zhao, Rui-Ke,Gu, Guo-Hao Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.11

Background: ABC proteins are one key type of transport superfamilies which undertake majority of drug transport, which affect the osteosarcoma response to chemotherapeutics. Previous studies have suggested the association between ABC polymorphisms and osteosarcoma response. However, the results of previous studies remain controversial. Therefore, we perform a meta-analysis to get a more precise estimation of this association. The association between ABC polymorphisms and osteosarcoma response was assessed by odds ratios (ORs) together with their 95% confidence intervals (CIs). Three polymorphisms of ABC including ABCB1 rs1128503, ABCC3 rs4148416 and ABCC2 rs717620 polymorphism were investigated. Overall, significant association was observed between ABCC3 rs4148416 polymorphism and osteosarcoma response under allele contrast (T vs. C: OR=1.73, 95%CI=1.09-2.74, P=0.019), homozygote comparison (TT vs. CC: OR=2.00, 95%CI=1.25-3.23, P=0.004), recessive genetic model (TT vs. TC/CC: OR=1.80, 95%CI=1.14-2.84, P=0.011) and dominant genetic model (TT/TC vs. CC: OR=1.70, 95%CI=1.20-2.42, P=0.003). Moreover, significant association was also observed in Caucasian population rather than Asian population for ABCB1 rs1128503 polymorphism. We conclude that ABCC3 rs4148416 polymorphism was significantly associated with poor osteosarcoma response and ABCB1 rs1128503 polymorphism was significantly associated with good osteosarcoma response in Caucasian population rather than Asian population.