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Shear lag effect in steel-concrete composite beam in hogging moment
Da Luo,Zhongwen Zhang,Bing Li 국제구조공학회 2019 Steel and Composite Structures, An International J Vol.31 No.1
Shear lag effect can be an important phenomenon to consider in design of the steel-concrete composite beams. Researchers have found that the effect can be strongly related with the moment distribution, the stiffness and the ductility of the composite beams. For continuous composite beams expected to sustain hogging moment, the shear lag effect can be more distinct as cracking of the concrete slab reduces its shear stiffness. Despite its influences on behaviour of the steel-concrete composite beams, a method for calculating the shear lag effect in steel-concrete composite beams sustaining hogging moment is still not available. Shear lag effect in steel-concrete composite beams sustaining hogging moment is investigated in this paper. A method was proposed specifically for predicting the effect in the cracked part of the steel-concrete composite beam. The method is validated against available experimental data. At last, FE studies are conducted for steel-concrete composite beams with different design parameters, loading conditions and boundary conditions to further investigate the shear lag effect and compare with the proposed method.
Moment redistribution of RC continuous beams: Re-examination of code provisions
Da Luo,Zhongwen Zhang,Bing Li 국제구조공학회 2023 Structural Engineering and Mechanics, An Int'l Jou Vol.85 No.5
Many codes allow designers to use the bending moment diagram computed by elastic analysis and modify it by a certain amount of moment redistribution (MR) to account for plastic behaviour of continuous beams. However, several researchers indicated that the MR at the ultimate limit state (u) for some beams deviate significantly from the specified values of various codes. This paper examines the applicability of the provisions on u in ACI 318-19 and Eurocode 2 through numerical investigations and comprehensively explores the influencing factors. The results show that some parameters not considered in those codes influence u to a certain extent, where the ratio of tensile reinforcement ratio at intermediate support to tensile reinforcement ratio at midspan (s1/s2) and load type are crucial parameters to consider. The specific combination of these two parameters may make the codes overestimate or significantly underestimate the u. On the other hand, the yield state of both critical sections is found to have an important influence on the influence degree of each parameter on u. The yield conditions are investigated, and an empirical judgment equation is proposed. In addition, the influence laws of the critical parameters on u have been further proved by theoretical derivation. Finally, due to t is found to have a better linear correlation with βu than xu/d, equations as a function of t for predicting the u of continuous beams under the two loads are proposed, respectively.
Zhang Hong,Zhou Qing-Ming,Li Xiao-Da,Xie Yi,Duan Xin,Min Feng-Ling,Liu Bing,Yuan Zhi-Gang The Pharmaceutical Society of Korea 2006 Archives of Pharmacal Research Vol.29 No.2
We investigated the effects of Ginsenoside $R_e$ on human sperm motility in fertile and asthenozoospermic infertile individuals in vitro and the mechanism by which the Ginsenosides play their roles. The semen samples were obtained from 10 fertile volunteers and 10 asthenozoospermic infertile patients. Spermatozoa were separated by Percoll and incubated with 0, 1, 10 or $100\;{\mu}M$ of Ginsenoside $R_e$. Total sperm motility and progressive motility were measured by computer-aided sperm analyzer (CASA). Nitric oxide synthase (NOS) activity was determined by the $^{3}H$-arginine to $^{3}H$-citrulline conversion assay, and the NOS protein was examined by the Western blot analysis. The production of sperm nitric oxide (NO) was detected using the Griess reaction. The results showed that Ginsenoside $R_e$ significantly enhanced both fertile and infertile sperm motility, NOS activity and NO production in a concentration-dependent manner. Sodium nitroprusside (SNP, 100 nM), a NO donor, mimicked the effects of Ginsenoside $R_e$. And pretreatment with a NOS inhibitor $N^{w}$-Nitro-L-arginine methyl ester (L-NAME, $100\;{\mu}M$) or a NO scavenger N-Acetyl-L-cysteine (LNAC, 1 mM) completely blocked the effects of Ginsenoside $R_e$. Data suggested that Ginsenoside $R_e$ is beneficial to sperm motility, and that induction of NOS to increase NO production may be involved in this benefit.
Hong Zhang,Qing-Ming Zhou,Xiao-Da Li,Yi Xie,Xin Duan,Feng-Ling Min,Bing Liu,Zhi-Gang Yuan 대한약학회 2006 Archives of Pharmacal Research Vol.29 No.2
We investigated the effects of Ginsenoside Re on human sperm motility in fertile and asthenozoospermic infertile individuals in vitro and the mechanism by which the Ginsenosides play their roles. The semen samples were obtained from 10 fertile volunteers and 10 asthenozoospermic infertile patients. Spermatozoa were separated by Percoll and incubated with 0, 1, 10 or 100 µM of Ginsenoside Re. Total sperm motility and progressive motility were measured by computer-aided sperm analyzer (CASA). Nitric oxide synthase (NOS) activity was determined by the 3H-arginine to 3H-citrulline conversion assay, and the NOS protein was examined by the Western blot analysis. The production of sperm nitric oxide (NO) was detected using the Griess reaction. The results showed that Ginsenoside Re significantly enhanced both fertile and infertile sperm motility, NOS activity and NO production in a concentration-dependent manner. Sodium nitroprusside (SNP, 100 nM), a NO donor, mimicked the effects of Ginsenoside Re. And pretreatment with a NOS inhibitor Nω-Nitro-L-arginine methyl ester (L-NAME, 100 µM) or a NO scavenger N-Acetyl-L-cysteine (LNAC, 1 mM) completely blocked the effects of Ginsenoside Re. Data suggested that Ginsenoside Re is beneficial to sperm motility, and that induction of NOS to increase NO production may be involved in this benefit.
Gold Immunolocalization of Rubisco and Rubisco Activase in Pyrenoid of Chlamydomonas reinhardtii
He, Pei-Min,Zhang, Da-Bing,Chen, Geng-Yun,Liu, Qi-Gen,Wu, Wei-Ning The Korean Society of Phycology 2003 ALGAE Vol.18 No.2
The pyrenoid ultrastructure and distribution of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) and Rubisco activase in the chloroplasts of Chlamydomonas reinhardtii was studied using the immunogold localization technology with electron microscopy. There were several tubular thylakoids invading in the pyrenoid matrix to form several spokewise channels. The connections between pyrenoid matrix and stroma of chloroplast were the partial of channels. The starch sheath surrounding the pyrenoid was separated into several parts by the connections in transection. Some thylakoids were packed together near the connections in one side of the pyrenoid. Those special structures might be used to transport substance between pyrenoid and stroma of chloroplasts. With the antibody raised against the large subunits of Rubsico from C. protothecoides, the result of the gold immunolocalization of Rubisco in Chlamydomonas reinhardtii showed most of the gold particles heavily labeled the pyrenoid matrix, as well as the starch sheath matrix, and very few in the stroma of chloroplasts. The gold particle density was 880.00 $\pm$ 164.32, 190.00 $\pm$ 152.39 and 9.60 $\pm$ 5.37 ${\mu}m^{-2}$ in pyrenoid matrix, starch sheath and stroma region of chloroplast respectively (background: 5.67 $\pm$ 1.53 ${\mu}m^{-2}$). 99.59% of the total Rubiscos was calculated to be concentrated in the pyrenoid matrix and starch sheath by spatial densities. The gold immunolocalization of Rubisco activase also showed that Rubisco activase was mainly concentrated in the periphery of the pyrenoid and the starch sheath (the density was as high as 229.69 $\pm$ 96.96 ${\mu}m^{-2}$). There were very few gold particles located in the stroma of chloroplasts. These results indicated that pyrenoid surface and starch sheath was the site for Rubisco activation and $CO_2$ fixation, which supported the suggestion that pyrenoids perform photosynthesis function.
Hai-bin Wei,Bing-yi Guo,Yao-fen Tu,Xuan-han Hu,Wei Zheng,Da-hong Zhang,Jian Zhuo 대한비뇨의학회 2022 Investigative and Clinical Urology Vol.63 No.3
Purpose: The selection of open prostatectomy (OP) over transurethral laser surgery is controversial for large volume prostates. Thus, we aim to compare the efficacy and safety of transurethral laser versus OP, and provide the latest evidence of clinical practice for large-sized benign prostatic hyperplasia (BPH). Materials and Methods: This meta-analysis used Review Manager V5.3 software and the systematic literature search of Cochrane Library, Embase, PubMed, and Web of Science datasets was performed for citations published from 2000 to 2020 that compared transurethral laser with OP for the treatment of large BPH. Variables of interest assessing the two techniques included clinical characteristics, and the perioperation-, effectiveness-, and complication-related outcomes. Results: The meta-analysis included twelve studies containing 1,514 patients, with 792 laser and 722 OP. The transurethral laser group was associated with shorter hospital stay and catheterization duration, and less hemoglobin decreased in the perioperative variables. There was no significant difference in the international prostate symptom score, post-void residual urine volume, maximum flow rate, and quality of life score. Transurethral laser group had a significantly lower incidence of blood transfusion than OP group (odds ratio, 0.10; 95% confidence interval, 0.05 to 0.19; p<0.001; I2=8%), and no statistical differences were found with respect to the other complications. Conclusions: Both OP and transurethral laser prostatectomy are effective and safe treatments for large prostate adenomas. With these advantages of less blood loss and transfusion, and shorter catheterization time and hospital stay, laser may be a better choice for large BPH.
Jia-Yu Lv,Ning-Ning Zhang,Ya-Wei Du,Ying Wu,Tian-Qiang Song,Ya-Min Zhang,Yan Qu,Yu-Xin Liu,Jie Gu,Ze-Yu Wang,Yi-Bo Qiu,Bing Yang,Da-Zhi Tian,Qing-Jun Guo,Li Zhang,Ji-San Sun,Yan Xie,Zheng-Lu Wang,Xin 연세대학교의과대학 2021 Yonsei medical journal Vol.62 No.1
Purpose: The aim of this study was to compare the efficacy of liver transplantation (LT) and liver resection (LR) for hepatocellularcarcinoma (HCC) patients with portal vein tumor thrombus (PVTT) and to investigate risk factors affecting prognosis. Materials and Methods: A total of 94 HCC patients with PVTT type I (segmental PVTT) and PVTT type II (lobar PVTT) were involvedand divided into LR (n=47) and LT groups (n=47). Recurrence-free survival (RFS) and overall survival (OS) were comparedbefore and after inverse probability of treatment weighting (IPTW). Prognostic factors for RFS and OS were explored. Results: Two treatment groups were well-balanced using IPTW. In the entire cohort, LT provided a better prognosis than LR. Among patients with PVTT type I, RFS was better with LT (p=0.039); OS was not different significantly between LT and LR(p=0.093). In subgroup analysis of PVTT type I patients with α-fetoprotein (AFP) levels >200 ng/mL, LT elicited significantly longermedian RFS (18.0 months vs. 2.1 months, p=0.022) and relatively longer median OS time (23.6 months vs. 9.8 months, p=0.065). Among patients with PVTT type II, no significant differences in RFS and OS were found between LT and LR (p=0.115 and 0.335,respectively). Multivariate analyses showed treatment allocation (LR), tumor size (>5 cm), AFP and aspartate aminotransferase(AST) levels to be risk factors of RFS and treatment allocation (LR), AFP and AST as risk factors for OS. Conclusion: LT appeared to afford a better prognosis for HCC with PVTT type I than LR, especially in patients with AFP levels>200 ng/mL.