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Xiao‑Bo Mei,Bao‑Chuan Liu,Wei Jiang,Quan Xu,Qi‑Dong Zhang,Yu‑Bai Ma,Fang‑Qiu Zu 대한금속·재료학회 2020 METALS AND MATERIALS International Vol.26 No.9
The influence of cooling rates on the mechanical properties of a Zr-based bulk metallic glass prepared with high rheologicalrate forming (HRRF) was investigated and compared with traditional suction cast methods. Amorphous samples of Zr57Cu-20Ni8Al10Ag5 were prepared in copper molds with different sizes in order to obtain different cooling rates for both HRRFand traditional cast methods. These specimens were subjected to compression experiments, including microhardness testing,X-ray diffraction testing and differential scanning calorimetry analysis. The results indicate that the plasticity of the samplesformed by HRRF are higher than that of the as-cast ones at the same cooling rates, while the microhardness manifests theopposite principle. As the cooling rate increases further, the difference in plasticity further increases between two methods,indicating that the plasticity of metallic glasses is more sensitive to cooling rates during the HRRF process. At the core ofthis phenomenon is the fact that HRRF methods can introduce more free volume into glasses than traditional cast methodswith an elevated cooling rate are able to.
A New ent-Kaurane type Diterpenoid Glycoside from Inula japonica Thunb
Jiang Jiang Qin,Jia Xian Zhu,Wei Dong Zhang1,2,Yan Zhu,Jian Jun Fu,Xiao Hua Liu,Hui Zi Jin 대한약학회 2009 Archives of Pharmacal Research Vol.32 No.10
A new ent-kaurane type diterpenoid glycoside, 17-O-β-D-glucopyranosyl-16α-ent-kauran-19-oic acid (1), together with 17-hydroxy-16α-ent-kauran-19-oic acid (2), 16α,17-dihydroxyl-ent-kauran-19-oic acid (3), and 16α-hydroxy-17-acetoxy-ent- kauran-19-oic acid (4) were isolated from the aerial parts of Inula japonica Thunb. The structure of 1 was determined mainly by use of 1D and 2D NMR spectroscopic techniques including HSQC, 1H-1H COSY, HMBC, and NOESY. In addition, 4 exhibited significant inhibitory activity on NO production in LPS-stimulated RAW264.7 cells with IC50 value of 14.3 μg/mL.
Xiao-Feng Zhang,Peng Dong,Ying-Jie Zhang,Xi-Kun Yang,Shu-Biao Xia,Zhen-Hua Jin,Ming-Li Xu 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2017 NANO Vol.12 No.3
Multi-walled carbon nanotubes (MWCNTs) were modified by hydrogen fluoride (HF) in a simple method. With the help of fluorine, Pd nanoparticles (3.9 nm) synthesized by a one-step photochemical reduction were uniformly self-assembled on the active sites of functionalized MWCNTs and a new catalyst (Pd/HF-MWCNT) was obtained. UV–Vis absorption spectra, transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) were used. The results demonstrated that –F groups were introduced onto the surface of MWCNTs and C–F chemical bonds were formed. In addition, the electronic structure of Pd was changed. Pd–F coordination bond maybe formed between F atom and Pd atom. Cyclic voltammetry and chronoamperometry tests indicated that electrocatalytic activity of Pd/HF-MWCNTs catalyst for methanol in alkaline medium was about 1.6 times higher than that of the commercial Pd/C (JM) catalyst at the same condition. This new functionalized method has the advantages of simple step and safe operation. It is very significant to improve the wide application of MWCNTs and the commercial development of direct methanol fuel cells (DMFCs).
Research on steady characteristics of human-robot system for preventing elderly falls during walking
Xiao Dong Zhang,Xiaoqi Mu,Liangliang Li,Ahmad Bala Alhassan,Khaled Kadry Hamza 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.9
Due to the ever-increasing demand of caregivers and the high cost of nursing the elderly, researchers have been developing the elderly assistant robots (EARs) for assisting the elderly. To improve the safety of the elderly during walking, the steady characteristics of the EAR are discussed for preventing elderly falls during walking in this paper. Initially, the walking elderly was modeled as an inverted pendulum, and the steadiness region of the human and the general elderly fall conditions were obtained. The dynamics of the human-robot system were derived for preventing the general elderly falls. Also, the steadiness of the human and the robot were analyzed, respectively. Finally, experiments were conducted to verify the effectiveness of the models. The results demonstrated that the system met the requirements of steadiness, and hence, the designed robot could prevent elderly fall during walking. Thus, this study provides a theoretical basis for the effective control and the practical application of the EARs.
The treatment effect of novel hGHRH homodimer to male infertility hamster
Zhang, Xu-Dong,Guo, Xiao-Yuan,Tang, Jing-Xuan,Yue, Lin-Na,Zhang, Juan-Hui,Liu, Tao,Dong, Yu-Xia,Tang, Song-Shan The Korean Society of Pharmacology 2018 The Korean Journal of Physiology & Pharmacology Vol.22 No.6
Extra-hypothalamic growth hormone-releasing hormone (GHRH) plays an important role in reproduction. To study the treatment effect of Grin (a novel hGHRH homodimer), the infertility models of 85 male Chinese hamsters were established by intraperitoneally injecting 20 mg/kg of cyclophosphamide once in a week for 5 weeks and the treatment with Grin or human menopausal gonadotropin (hMG) as positive control was evaluated by performing a 3-week mating experiment. 2-8 mg/kg of Grin and 200 U/kg of hMG showed similar effect and different pathological characteristics. Compared to the single cyclophosphamide group (0%), the pregnancy rates (H-, M-, L-Grin 26.7, 30.8, 31.3%, and hMG 31.3%) showed significant difference, but there was no difference between the hMG and Grin groups. The single cyclophosphamide group presented loose tubules with pathologic vacuoles and significant TUNEL positive cells. Grin induced less weight of body or testis, compactly aligned tubules with little intra-lumens, whereas hMG caused more weight of body or testis, enlarging tubules with annular clearance. Grin presented a dose-dependent manner or cell differentiation-dependentincrease in testicular GHRH receptor, and did not impact the levels of blood and testicular GH, testosterone. Grin promotes fertility by proliferating and differentiating primitive cells through up-regulating testicular GHRH receptor without triggering GH secretion, which might solve the etiology of oligoasthenozoospermia.
Zhang, Chuan-Jin,Tang, Yi,Han, Dong,Zhang, Hui,Zhang, Xiao,Wang, Ke The Korean Institute of Power Electronics 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.3
A novel Virtual Space Vector (VSV) modulation strategy for complete control of potential neutral point (NP) issues is proposed in this paper. The neutral point potential balancing problems of multi-level converters, which include elimination of low frequency oscillations and self-balancing for NP dc unbalance, are investigated first. Then a set of improved virtual space vectors with dynamic adjustment factors are introduced and a multi-objective optimization algorithm which aims to optimize these adjustment factors is presented in this paper. The improved virtual space vectors and the multi-objective optimization algorithm constitute the novel Virtual Space Vector modulation. The proposed novel Virtual Space Vector modulation can simultaneously recover NP dc unbalance and eliminate low frequency oscillations of the neutral point. Experiment results show that the proposed strategy has excellent performance, and that both of the neutral point potential issues can be solved.
Zhang Xiao-Qing,Wang Yi-He,Sun Li,Dong Bao-Qiang,Sui Yue-Jiao,Dong Jia-Zi,Han Yang 사단법인약침학회 2022 Journal of Acupuncture & Meridian Studies Vol.15 No.5
Background: Electroacupuncture (EA) is a widely used traditional Chinese medicine method to manage various diseases, including cerebral ischemia-reperfusion injury (CIRI). Objectives: We assessed the neuroprotective effects of EA and examined its mechanism in a rat model of the middle cerebral artery occlusion-reperfusion (MCAO/R). The gait analysis was performed to evaluate the neuroprotective effects. Western blot and immunohistochemistry assays were carried out to determine the molecular mechanisms of EA. Methods: Male SD rats were randomly divided into the sham operation group, right MCAO/R group, and EA group. EA was administered every day (4/20 Hz, 10 min/1 d) at the following acupoints: Baihui (DU20), Yintang (EX-HN3), and Zusanli (ST36). Gait and motor function were analyzed from day 8 onward. Results: The plantar support and balance coordination of MCAO/R rats decreased, and the cellular structure of the ischemic penumbra was unclear. EA improved the gait dynamics of the rats, adjusted the cell structure, further activated astrocytes, and increased the expression and phosphorylation of phosphoinositide 3-kinase/protein kinase B (PI3K/PKB or AKT). Conclusion: EA promoted astrocyte-related effects in the rat model. Our findings suggest that the neuroprotective mechanism of EA may be related to the activation of the PI3K/ AKT signaling pathway. The intervention enhanced brain protection and improved motor functions.
Distributed Consensus Control for Automatic Gauge Control of Hot Strip Mills
Xiao-Dong Zhang,Shao-Shu Gao,Wei-Xi Gao,Xu-Ying Wang,Wei Zhang 제어·로봇·시스템학회 2021 International Journal of Control, Automation, and Vol.19 No.5
In this study, the distributed control strategy is proposed for the automatic gauge control(AGC) system, which is a typical multi-agent system. The distributed control protocol is developed with the subspace identification method using the measurements of the local agent and its neighbors directly,without any knowledge of the AGC system dynamics. The stability analysis of the multi-agent system with the proposed control protocol is given. In addition, the consensus control protocol with communication time delay is investigated. Finally, simulation results are carried out to verify the feasibility and effectiveness of the proposed control strategy.
Association of Six Susceptibility Loci with Prostate Cancer in Northern Chinese Men
Zhang, Yu-Rong,Xu, Yong,Yang, Kuo,Liu, Ming,Wei, Dong,Zhang, Yao-Guang,Shi, Xiao-Hong,Wang, Jian-Ye,Yang, Fan,Wang, Xin,Liang, Si-Ying,Zhao, Cheng-Xiao,Wang, Fei,Chen, Xin,Sun, Liang,Zhu, Xiao-Quan,Zh Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.12
Background/Aim: Six prostate cancer (PCa) susceptibility loci were identified in a genome-wide association study (GWAS) in populations of European decent. However, the associations of these 6 single-nucleotide polymorphisms (SNPs) with PCa has remained tobe clarified in men in Northern China. This study aimed to explore the loci associated with PCa risk in a Northern Chinese population. Methods: Blood samples and clinical information of 289 PCa patients and 288 controls from Beijing and Tianjin were collected. All risk SNPs were genotyped using polymerase chain reaction (PCR)-high resolution melting curve technology and gene sequencing. Associations between PCa and clinical covariates (age at diagnosis, prostate-specific antigen [PSA], Gleason score, tumor stage, and level of aggressiveness) and frequencies of alleles and genotypes of these SNPs were analyzed using genetic statistics. Results: Among the candidate SNPs, 11p15 (rs7127900, A) was associated with PCa risk (P = 0.02, odds ratio [OR] = 1.64, 95% confidence interval [CI] = 1.09-2.46). Genotypes showed differences between cases and controls on 11p15 (rs7127900, A), 11q13 (rs7931342, T), and HNF1B (rs4430796, A) (P = 0.03, P = 0.01, and P = 0.04, respectively). The genotype TG on 11q13 (rs7931342, T) was positively associated with an increased Gleason score (P = 0.04, OR = 2.15, 95% CI = 1.02-4.55). Patients carrying TG on 17q24 (rs1859962, G) were negatively associated with an increased body mass index (BMI) (P = 0.03, OR = 0.44, 95% CI = 0.21-0.92) while those with AG on HNF1B (rs4430796, A) were more likely to have PSA increase (P = 0.002). Conclusion: Our study suggests that 11p15 (rs7127900, A) could be a susceptibility locus associated with PCa in Northern Chinese. Genotype TG on 11q13 (rs7931342, T) could be related to an increased Gleason score, AG on HNF1B (rs4430796, A) could be associated with PSA increase, and TG on 17q24 (rs1859962, G) could be negatively associated with an increased BMI in Chinese men with PCa.