Experimental and numerical studies of miniature bar-typed structural fuses with Teflon pads

Sen Yang,Yan Liu,Yu Lin,Dongzhi Guan,Hanbin Ge,Zhengxing Guo,Wenguang Liu 국제구조공학회 2021 Steel and Composite Structures, An International J Vol.41 No.4

Many studies have proved that structural fuses could improve the seismic performance of structures efficiently. A structural fuse named the miniature bar-typed structural fuse (MBSF) has been proposed and investigated by the authors, which consists of a central core bar, a confining tube. To further improve the mechanic performances of the MBSFs under compressive loadings, Teflon pads are introduced to adjust the contact and friction status between the core bar and the confining tube. Three groups of specimens were discussed including the specimen with a single cutting line (SC), the specimen with double cutting lines (DC), and the specimen with triple cutting lines (TC). The results show that the hysteretic performances of the fuses are improved with the help of Teflon pads. The compression strength adjustment factor declines when Teflon pads are appended. Numerical and theoretical analyses are also conducted which expounded the effect of the Teflon pads. Different plastic buckling deformation principles of the core bars are compared by the theoretical analysis. It is shown that Shanley’s theory fits the numerical results well, which is recommended for the theoretical calculation of the proposed MBSFs.

Experimental Research on Vertical Mechanical Performance of Embedded Through-penetrating Steel-Concrete Composite Joint in High-Temperature Gas-Cooled Reactor Pebble-Bed Module

Peiyao Zhang,Quanquan Guo,Sen Pang,Yunlun Sun,Yan Chen 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.1

The high-temperature gas-cooled reactor pebble-bed module project is the first commercial Generation-IV NPP(Nuclear Power Plant) in China. A new joint is used for the vertical support of RPV(ReactorPressure Vessel). The steel corbel is integrally embedded into the reactor-cabin wall through eightasymmetrically arranged pre-stressed high-strength bolts, achieving the different path transmission ofshear force and moment. The vertical monotonic loading test of two specimens is conducted. The resultsshow that the failure mode of the joint is bolt fracture. There is no prominent yield stage in the wholeloading process. The stress of bolts is linearly distributed along the height of corbel at initial loading. Asthe load increases, the height of neutral axis of bolts gradually decreases. The upper and lower edges ofthe wall opening contact the corbel plate to restrict the rotation of the corbel. During the loading, thepre-stress of some bolts decreases. The increase of the pre-stress strength ratio of bolts has no noticeableeffect on the structure stiffness, but it reduces the ultimate bearing capacity of the joint. A simplifiedcalculation model for the elastic stage of the joint is established, and the estimation results are in goodagreement with the experimental results

Current situation and future prospects for beef production in China - A review

Li, Xiang Zi,Yan, Chang Guo,Zan, Lin Sen Asian Australasian Association of Animal Productio 2018 Animal Bioscience Vol.31 No.7

The beef industry is an important part of livestock and meat production in China. China ranks third in the world for beef production. With the rapid development of the Chinese economy, beef consumption has grown rapidly, and beef consumption has been increasing with rising per capita gross domestic production. However, the domestic beef industry in China has not been able to keep pace with growth in consumption, making China a net importer of beef from other countries. Moreover, the volume of production has increased little despite rising demand. The slowing of growth in beef production in recent years has led to a sharp rise in beef prices. Domestic beef production and consumption is restricted by a shortage of beef cattle inventory. The Chinese beef industry is facing many technical problems including transformation of traditional practices, feeding and management systems, and genetic improvement of cattle breeds. The long-term, sustainable development of the Chinese beef industry is an important issue for China.

Optimal Timing of Radiotherapy with Alternating/Sequential Radio-Chemotherapy for Limited-stage Small Cell Lung Cancer

Wang, Li-Jie,Liu, Xiu-Ju,Guan, Yan,Zhang, Chu-Feng,Wang, Peng,Li, Yan,Guo, Qi-Sen Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.14

Objective: To investigate the optimal timing of radiotherapy with alternating/sequential radio-chemotherapy for limited-stage small cell lung cancer (LS-SCLC). Methods: 91 patients with LS-SCLC were retrospectively analyzed and divided into two groups according to the number of chemotherapy cycles before radiotherapy. If the patient received radiotherapy after 3 cycles or fewer cycles of chemotherapy, classification was into the early group, if not, into the late group. All patients received 6 cycles of standard chemotherapy (EP/EC) and conventional radiotherapy (56 gy~ 60 gy/28 f ~30 f). Results: The response rate (RR) of the early and late groups were 85.7% and 81.6%, respectively, with no significant difference (p>0.05). In contrast, the progression-free survival (PFS) in the early group was better than that in the late group (11.8 months vs 9.86 months), and the difference was significant (p<0.05). There was no significant difference between two groups in adverse reactions, which gastrointestinal irritation and bone marrow suppression being the most common (p>0.05). Conclusions: Radiotherapy after 3 cycles or fewer cycles of chemotherapy does not bring significant benefits for RR of patients with LS-SCLC, but it could significantly prolong their PFS without increase in adverse reactions.

Prognostic Significance of Overexpression of EZH2 and H3k27me3 Proteins in Gastric Cancer

He, Long-Jun,Cai, Mu-Yan,Xu, Guo-Liang,Li, Jian-Jun,Weng, Zi-Jin,Xu, Da-Zhi,Luo, Guang-Yu,Zhu, Sen-Lin,Xie, Dan Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.7

The enhancer of zeste homolog 2 (EZH2) methyl transferase and histone 3 lysine 27 (H3K27me3) protein can repress gene transcription, and their aberrant expression has been observed in various human cancers. This study determined their expression levels in gastric cancer tissues with reference to clinicopathological features and patient survival. We collected 117 gastric cancer and corresponding normal tissues for immunohistochemistry analysis. In gastric cancers, 82/117 (70.1%) were positive for EZH2 and 66/117 (56.4%) for H3K27me3 proteins in contrast to only 5.41% and 7.25% of normal gastric mucosa specimens, respectively. Kaplan-Meier survival data showed the average overall and disease-free survival of EZH2 high expression patients was 25.2 and 20.2 months, respectively, shorter than that with EZH2 low expression (40.5 and 35.9 months). The average overall survival and disease-free survival of high H3K27me3 expression patients was 23.4 and 17.4 months, shorter than without H3K27me3 expression (37.6 and 34.5 months). The average overall survival and disease-free survival of patients with both EZH2 and H3K27me3 expression was 18.8 and 12.9 months, respectively, shorter than that with either alone (34.7 and 31.2 months) or with low levels of both (43.9 and 39.9 months). Multivariate Cox regression analysis showed that H3K27me3 and EZH2 expression, tumor size differentiation and clinical stage were all independent prognostic factors for predicting patient survival. This study demonstrated that detection of both EZH2 and H3K27me3 proteins can predict poor survival of gastric cancer patients, superior to single protein detection. In addition, H3K27me3 and EZH2 protein expression could predict lymph node metastasis.

Highly efficient synthesis of novel methyl 13²-methylene mesopyropheophorbide <i>a</i> and its stereoselective Michael addition reaction

Li, Jiazhu,Liu, Yang,Xu, Xi-Sen,Li, Yan-Long,Zhang, Shan-Guo,Yoon, Il,Shim, Young Key,Wang, Jin-Jun,Yin, Jun-Gang The Royal Society of Chemistry 2015 Organic & Biomolecular Chemistry Vol.13 No.7

<P>Treatment of methyl mesopyropheophorbide <I>a</I> with formaldehyde under basic conditions gave a novel 13<SUP>2</SUP>-methylene derivative in 85% yield; under acidic conditions, the corresponding 20-hydroxymethyl derivative was obtained in 65% yield. The high reactivity of the enone structural motif existed in the former product provides a unique way to construct some novel chlorophyll <I>a</I> derivatives for various applications. Stereoselective Michael reaction of this compound is studied and discussed.</P> <P>Graphic Abstract</P><P>pH-Dependent regioselective condensation of methyl mesopyropheophorbide <I>a</I> with HCHO is studied and stereoselective Michael reaction of the 13<SUP>2</SUP>-methylene product is also discussed. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c4ob02491e'> </P>

An integrated study of tyrosinase inhibition by rutin: progress using a computational simulation.

Si, Yue-Xiu,Yin, Shang-Jun,Oh, Sangho,Wang, Zhi-Jiang,Ye, Sen,Yan, Li,Yang, Jun-Mo,Park, Yong-Doo,Lee, Jinhyuk,Qian, Guo-Ying Adenine Press 2012 Journal of biomolecular structure & dynamics Vol.29 No.5

<P>Tyrosinase inhibition studies have recently gained the attention of researchers due to their potential application values. We simulated docking (binding energies for AutoDock Vina: -9.1 kcal/mol) and performed a molecular dynamics simulation to verify docking results between tyrosinase and rutin. The docking results suggest that rutin mostly interacts with histidine residues located in the active site. A 10 ns molecular dynamics simulation showed that one copper ion at the tyrosinase active site was responsible for the interaction with rutin. Kinetic analyses showed that rutin-mediated inactivation followed a first-order reaction and mono- and biphasic rate constants occurred with rutin. The inhibition was a typical competitive type with K(i) = 1.100.25 mM. Measurements of intrinsic and ANS-binding fluorescences showed that rutin showed a relatively strong binding affinity for tyrosinase and one possible binding site that could be a copper was detected accompanying with a hydrophobic exposure of tyrosinase. Cell viability testing with rutin in HaCaT keratinocytes showed that no toxic effects were produced. Taken together, rutin has the potential to be a potent anti-pigment agent. The strategy of predicting tyrosinase inhibition based on hydroxyl group number and computational simulation may prove useful for the screening of potential tyrosinase inhibitors.</P>

Theoretical study on the hydrolysis mechanism of N,N-dimethyl-N′-(2-oxo-1, 2-dihydro-pyrimidinyl)formamidine: Water-assisted mechanism and cluster-continuum model

Wu, Yong,Jin, Lu,Xue, Ying,Xie, Dai Qian,Kim, Chan Kyung,Guo, Yong,Yan, Guo Sen Wiley Subscription Services, Inc., A Wiley Company 2008 Journal of computational chemistry Vol.29 No.8

<P>The hydrolysis reaction of N,N-dimethyl-N′-(2-oxo-1, 2-dihydro-pyrimidinyl)formamidine (DMPFA), a model compound of the antivirus drug amidine-3TC (3TC = 2′, 3′-dideoxy-3′-thiacytidine), is investigated by the hybrid density functional theory B3LYP/6-31+G (d,p) method. The hydrolysis reaction of the title compound is predicted to undergo via two pathways, each of which is a stepwise process. Path A is the addition of H<SUB>2</SUB>O to the C&n.dbond;N double bond in the amidine group to form a tetrahedral structure in its first step, and then the transfer of the H atom of hydroxyl leads to the corresponding products via four possible channels. Path B simultaneously involves the nucleophilic attack of H<SUB>2</SUB>O to the C atom of the C&n.dbond;N bond and the proton transfer to the N atom of amino group leading to the cleavage of the C&n.bond;N single bond in the amidine group. The results indicate that path A is more favorable than path B in the gas phase. Moreover, to simulate the title reaction in aqueous solution, water-assisted mechanism and the cluster-continuum model, based on the SCRF/CPCM model, are taken into account in our work. The results indicate that it is rational for two water molecules served as a bridge to assist in the first step of path A and that cytosine rather than the cytosine-substituted formamide should be released from the tetrahedral intermediate via s six-membered cycle transition state (channel 2). Our calculations exhibit that the process toward the tetrahedral intermediate is the rate-determining step both in the gas phase and in aqueous solution. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2008</P> <B>Graphic Abstract</B> <P> <img src='wiley_img/01928651-2008-29-8-JCC20883-gra001.gif' alt='wiley_img/01928651-2008-29-8-JCC20883-gra001'> </P>