Experimental investigation on the behaviour of UHPC-steel composite slabs under hogging moment

Xiao-Long Gao,Jun-Yan Wang,Chen Bian,Ru-Cheng Xiao,Biao Ma 국제구조공학회 2022 Steel and Composite Structures, An International J Vol.42 No.6

Ultra high performance concrete (UHPC) can be used in the UHPC-steel composite structures especially for bridge structures to achieve high stiffness and high fatigue resistance with low self-weight. The structural performances of UHPC-steel composite slabs subjected to hogging moment have a significant influence on the global stiffness and durability of UHPC-steel composite structures. In order to study the structural behaviors of non-steam-cured UHPC-steel composite slabs subjected to negative moment, five composite slabs combined the thin UHPC layers to steel plates via shear stud connecters with the diameter of 16mm were fabricated and tested under negative moment. The test program aimed to investigate the effect of stud spacing and longitudinal reinforcement ratios on the failure mode, load-deflection behaviors, cracking patterns, bond-slips, and carrying capacities of composite slabs subjected to negative moment. In addition, direct tensile tests for the dog-bone UHPC specimens with longitudinal reinforcement bars were carried out to study the effect of reinforcement bars on the tensile strength of UHPC in the thin structure members. Based on the experimental results, analytical models were also developed to predict the cracking load and ultimate load of UHPC-steel composite slabs subjected to negative moment.

Experimental studies of headed stud shear connectors in UHPC Steel composite slabs

Xiao-long Gao,Jun-Yan Wang,Jia-Bao Yan 국제구조공학회 2020 Structural Engineering and Mechanics, An Int'l Jou Vol.74 No.5

Due to the high compressive and tensile strength of ultra-high performance concrete (UHPC), UHPC used in steel concrete composite structures provided thinner concrete layer compared to ordinary concrete. This leaded to the headed stud shear connectors embedded in UHPC had a low aspect ratio. In order to systematic investigate the effect of headed stud with low aspect ratio on the structural behaviors of steel UHPC composite structure s this paper firstly carried out a test program consisted of twelve push out specimens. The effects of stud height, aspect ratio and reinforcement bars in UHPC on the structural behaviors of headed studs were investigated. The push out test results shows that the increasing of stud height did not obviously influence the structural behaviors of headed studs and the aspect ratio of 2.16 was proved enough to take full advantage of the headed stud strength. Based on the test results, the equation considering the contribution of weld collar was modified to predict the shear strength of headed stud embedded in UHPC. The modified equation could accurately predict the shear strength of headed stud by comparing with the experimental results. On the basis of push out test results, bending tests consisted of three steel UHPC composite slabs were conducted to investigate the effect of shear connection degree on the structural behaviors of composite slabs. The bending test results revealed that the shear connection degree had a significantly influence on the failure modes and ultimate resistance of composite slabs and composite slab with connection degree of 96% in s hear span exhibited a ductile failure accompanied by the tensile yield of steel plate and crushing of UHPC. Finally, analytical model based on the failure mode of composite slabs was proposed to predict the ultimate resistance of steel UHPC composite slabs with different shear connection degrees at the interface.

ANXA2 Regulates the Behavior of SGC-7901 Cells

Sun, Meng-Yao,Xing, Rui-Huan,Gao, Xiao-Jie,Yu, Xiang,He, Hui-Min,Gao, Ning,Shi, Hong-Yan,Hu, Yan-Yan,Wang, Qi-Xuan,Xu, Jin-Hui,Hou, Ying-Chun Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.10

ANXA2, a member of the annexin family, is overexpressed and plays important roles in tumor development. However, the significance of ANXA2 expression in gastric carcinoma has not been clarified.To elucidate its roles in growth of gastric cancer, ANXA2 expression in SGC-7901 cells was inhibited with a designated siRNA, then cell proliferation, cell cycling, apoptosis and motility were determined by MTT assay, flow cytometry, Hoechst 33342 staining and wound healing assay, respectively. To further assess the behavior of ANXA2 deleted SGC-7901 cells, changes of microstructures were observed under fluorescence microscopy, laser scanning confocal microscopy and electron microscopy. We found that inhibition of ANXA2 expression caused cell proliferation to decrease significantly with G1 arrest, motility to be reduced with changes in pseudopodia/filopodia structure and F-actin and ${\beta}$-tubulin expression, and apoptosis to be enhanced albeit without significance. At the same time, ANXA2 deletion resulted in fewer pseudopodia/filopodia, non-stained areas were increased, contact inhibition among cells reappeared, and expression of F-actin and ${\beta}$-tubulin was decreased, with induction of polymerized disassembled forms. Taken together, these data suggest that ANXA2 overexpression is important to maintain the malignancy of cancer cells, and this member of the annexin family has potential to be considered as a target for the gene therapy of gastric carcinoma.

Kaempferol Suppresses Cisplatin-Induced Apoptosis Via Inductions of Heme Oxygenase-1 and Glutamate-Cysteine Ligase Catalytic Subunit in HEI-OC1 cells

Gao, Shang Shang,Choi, Byung-Min,Chen, Xiao Yan,Zhu, Ri Zhe,Kim, Youngho,So, HongSeob,Park, Raekil,Sung, Meesook,Kim, Bok-Ryang Springer-Verlag 2010 Pharmaceutical research Vol.27 No.2

New Triterpenoids from the Fruits of Schisandra wilsoniana and Their Biological Activities

Gao, Xue-Mei,Li, Yun-Qi,Shu, Li-Dan,Shen, Yan-Qiong,Yang, Li-Ying,Yang, Liu-Meng,Zheng, Yong-Tang,Sun, Han-Dong,Xiao, Wei-Lie,Hu, Qiu-Fen Korean Chemical Society 2013 Bulletin of the Korean Chemical Society Vol.34 No.3

Investigation of an organic extract of the fruits Schisandra wilsoniana led to the isolation of two new highly oxygenated nortriterpenoids, named schilancidilactones V-W (1-2). Their structures were elucidated by spectroscopic evidence. Compounds 1-2 feature a double bond between C-7 and C-8 compared with related known nortriterpenoids isolated from the genus Schisandra. Compounds 1 and 2 were tested for their anti-HIV-1 activities and cytotoxicity. The results revealed that compounds 1 and 2 showed moderate anti-HIV-1 activities with $EC_{50}$ 3.05 and 2.87 ${\mu}g/mL$, respectively, and compound 1 showed high cytotoxicity against KB and MDA-MB-231 cell with $IC_{50}$ values of 3.18 and 5.22 ${\mu}M$, respectively.

Analysis of the Optical Constants of Aluminum-doped Zinc-oxide Films by Using the Single-oscillator Model

Xiao-Yong Gao,Yan Liang,Qing-Geng Lin 한국물리학회 2010 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.57 No.4

A group of aluminum-doped zinc-oxide (AZO) films were prepared on glass substrates by directcurrent reactive magnetron sputtering at substrate temperatures (Ts) ranging from 170 ℃ to 210 ℃. The optical constants of the AZO films defined by using Caughy model were fitted in terms of a two-layer model by using the measured spectroscopic ellipsometric parameters. The refractive index dispersion data below the interband absorption edge of the AZO films were analyzed by using a single-oscillator model. The optical energy gap as-fitted by using the single-oscillator model demonstrated a blue and a red shift as T<SUB>s</SUB> increased from 170 ℃ to 200 ℃ and above 200 ℃, respectively. This could be attributed to a change in the free electron concentration, which was related to a change in the effective Al-doping efficiency. The calculated parameter β, related to the crystalline structure, indicated that the as-deposited AZO films fell into an ionic class even though β had a slight deviation from the ionic value. The β of the as-deposited AZO film at 200 ℃ largely remained in the range of ionic values, indicating a minimum deviation from the wurtzite structure. This denoted that Al is a very effective substitute for the zinc sites. Additionally, the calculated plasma frequency, hw<SUB>p</SUB>, remained in the violet region.

Monosaccharide as a Central Scaffold Toward the Construction of Salicylate-Based Bidentate PTP1B Inhibitors via Click Chemistry

Yan-Hui Tang,Min Hu,Xiao-Peng He,Sando Fahnbulleh,Cui Li,Li-Xin Gao,Li Sheng,Yun Tang,Jia Li,Guo-Rong Chen 대한화학회 2011 Bulletin of the Korean Chemical Society Vol.32 No.3

The discovery of carbohydrate-based bioactive compounds has recently received considerable interest in the drug development. This paper stresses on the application of 1-methoxy-O-glucoside as the central scaffold,whereas salicylic pharmacophores were introduced with diverse spatial orientations probing into the structural preference of an enzymatic target, i.e. protein tyrosine phosphatase 1B (PTP1B). By employing regioselective protection and deprotection strategy, 2,6-, 3,4-, 4,6- and 2,3-di-O-propynyl 1-methoxy-O-glucosides were previously synthesized and then coupled with azido salicylate via click chemistry in forming the desired bidentate salicylic glucosides with high yields. The inhibitory assay of the obtained triazolyl derivatives leads to the identification of the 2,3-disubstituted salicylic 1-methoxy-O-glucoside as the structurally privileged PTP1B inhibitor among this bidentate compound series with micromole-ranged IC50 value and reasonable selectivity over other homologous PTPs tested. In addition, docking simulation was conducted to propose a plausible binding mode of this authorized inhibitor with PTP1B. This research might furnish new insight toward the construction of structurally different bioactive compounds based on the monosaccharide scaffold.

Therapeutic Effect of Ginsenoside Rd in Rats with TNBS-Induced Recurrent Ulcerative Colitis

Xiao-Lai Yang,Yong-Jie Wu,Tian-Kang Guo,Yan-Hong Wang,Ming-Tang Gao,Hong Qin 대한약학회 2012 Archives of Pharmacal Research Vol.35 No.7

Ulcerative colitis (UC) is characterized by oxidative and nitrosative stress and neutrophil infiltration. In the present study, we aimed to investigate the therapeutic effect of ginsenoside Rd (GRd) in rats with 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced recurrent UC. After UC was twice-induced by intracolonic injection of TNBS, rats were intragastrically administered different doses of GRd per day for 7 days. The colonic lesions and inflammation were evaluated both histologically and biochemically. Compared with the TNBS group, GRd treatment facilitated recovery of pathologic changes in the colon after induction of recurrent UC, as evidenced by a significant reduction of colonic weight/length ratio and macroscopic and microscopic damage scores (p < 0.01). The myeloperoxidase and inducible nitric oxide synthase activities with malonyldialdehyde and nitric oxide levels in colonic tissues were significantly decreased in the GRd group compared with those in the TNBS group (p < 0.01). GRd treatment was associated with remarkably increased superoxide dismutase and glutathione peroxidase activities. Results showed a valuable effect of GRd against TNBS-induced recurrent UC by inhibiting neutrophil infiltration and promoting the antioxidant capacity of the damaged colonic tissue.

Topology optimization of material microstructures using energy-based homogenization method under specified initial material layout

Yan Zhang,Mi Xiao,Hao Li,Liang Gao 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.2

Due to multiple local optimums in the society of periodic material microstructure deign using topology optimization, it is widely recognized that the initial microstructure configuration can significantly influence the optimal design. This study investigates the effect of different initial material layouts of microstructure unit cell upon the optimal design, and proposes a microstructure initialization scheme to alleviate the dependency of the optimal design on its initial design. The effective elastic properties of microstructures are evaluated by the efficient energy-based homogenization method. Topology optimization models are formulated to seek the best microstructures with the extreme properties or desired properties under the prescribed volume constraints. Several typical numerical examples are presented to demonstrate the effectiveness of the proposed scheme. Numerical results show that the proposed scheme can reduce the sensitivity of the optimal design upon optimization parameters and be beneficial to achieve a stable and rapid convergence.

High-efficiency adsorption for both cationic and anionic dyes using graphene nanoribbons formed by atomic-hydrogen induced single-walled carbon nanotube carpets

Gao Yan,Liang Xilong,Han Shuangping,Wu Liang,Zhang Guofeng,Qin Chengbing,Bao Shanxia,Wang Qiang,Qi Lele,Xiao Liantuan 한국탄소학회 2020 Carbon Letters Vol.30 No.2

Carbonaceous materials are considered as potential adsorbents for organic dyes due to their unique structures which provide high aspect ratios, hydrophobic property, large efcient surface area, and easy surface modifcation. In this work, graphene nanoribbons (GNRs) were prepared by atomic hydrogen-induced treatment of single-walled carbon nanotube (SWCNTs), which inspire the idea of cutting and unzipping the SWCNTs carpets with the modifed in molecules prevent because of the unfolding of the side-walls. The unfolded spaces and uniform vertical arrangement not only enhance the active surface area, but also promote the electrostatic and π–π interactions between dyes and GNRs. The improved adsorption capacity of GNRs beyond original SWCNTs can be determined by the adsorption kinetics and isotherm, which are evaluated through adsorption batch experiments of the typical cationic methylene blue (MB) and anionic orange II (OII) dye, respectively. It is shown that the adsorption kinetics follow a pseudo second-order model while the adsorption isotherm could be determined by Langmuir model. The results reveal that the maximum adsorption capacities of GNRs for MB and OII are 280 and 265 mg/g, respectively. The GNRs present the highly efcient, cost efective, and environmental friendly properties for the commercial applications of wastewater treatment.