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On the stability of spacelike hypersurfaces with higher order mean curvature in a de Sitter space
Shicheng Zhang 대한수학회 2014 대한수학회보 Vol.51 No.5
The closed spacelike hypersurfaces with higher order mean curvature is discussed in a de Sitter space. The hypersurface is proved stable if and only if it is totally umbilical.
A MAXIMUM PRINCIPLE FOR COMPLETE HYPERSURFACES IN LOCALLY SYMMETRIC RIEMANNIAN MANIFOLD
Zhang, Shicheng Korean Mathematical Society 2014 대한수학회논문집 Vol.29 No.1
In this article, we apply the weak maximum principle in order to obtain a suitable characterization of the complete linearWeingarten hypersurfaces immersed in locally symmetric Riemannian manifold $N^{n+1}$. Under the assumption that the mean curvature attains its maximum and supposing an appropriated restriction on the norm of the traceless part of the second fundamental form, we prove that such a hypersurface must be either totally umbilical or hypersurface is an isoparametric hypersurface with two distinct principal curvatures one of which is simple.
ON THE STABILITY OF SPACELIKE HYPERSURFACES WITH HIGHER ORDER MEAN CURVATURE IN A DE SITTER SPACE
Zhang, Shicheng Korean Mathematical Society 2014 대한수학회보 Vol.51 No.5
The closed spacelike hypersurfaces with higher order mean curvature is discussed in a de Sitter space. The hypersurface is proved stable if and only if it is totally umbilical.
Determining Osteogenic Differentiation Efficacy of Pluripotent Stem Cells by Telomerase Activity
Siqi Zhang,Yuhua Sun,Yi Sui,Yan Li,Zuyuan Luo,Xiao Xu,Ping Zhou,Shicheng Wei 한국조직공학과 재생의학회 2018 조직공학과 재생의학 Vol.15 No.6
BACKGROUND: Bone tissue engineering based on pluripotent stem cells (PSCs) is a new approach to deal with bone defects. Protocols have been developed to generate osteoblasts from PSCs. However, the low efficiency of this process is still an important issue that needs to be resolved. Many studies have aimed to improve efficiency, but developing accurate methods to determine efficacy is also critical. Studies using pluripotency to estimate efficacy are rare. Telomerase is highly associated with pluripotency. METHODS: We have described a quantitative method to measure telomerase activity, telomeric repeat elongation assay based on quartz crystal microbalance (QCM). To investigate whether this method could be used to determine the efficiency of in vitro osteogenic differentiation based on pluripotency, we measured the pluripotency pattern of cultures through stemness gene expression, proliferation ability and telomerase activity, measured by QCM. RESULTS: We showed that the pluripotency pattern determined by QCM was similar to the patterns of proliferation ability and gene expression, which showed a slight upregulation at the late stages, within the context of the general downregulation tendency during differentiation. Additionally, a comprehensive gene expression pattern covering nearly every stage of differentiation was identified. CONCLUSION: Therefore, this assay may be powerful tools for determining the efficiency of differentiation systems based on pluripotency. In this study, we not only introduce a new method for determining efficiency based on pluripotency, but also provide more information about the characteristics of osteogenic differentiation which help facilitate future development of more efficient protocols.
Robust Consensus for Networked Mechanical Systems with Coupling Time Delay
Haibo Min,Shicheng Wang,Fuchun Sun,Jinsheng Zhang 제어·로봇·시스템학회 2012 International Journal of Control, Automation, and Vol.10 No.2
This paper studies the state consensus for a class of networked nonlinear mechanical systems with coupling time delay. In particular, robust consensus protocols for both deterministic and uncertain systems with time delay are investigated. For deterministic systems, we develop a P-like protocol which allows for variable coupling time delay. We show that it is sufficient to have only the relative position information together with a damping control term, whereas the relative velocity information is not needed for state consensus. Then, an adaptive robust control protocol is proposed for uncertain sys-tems with unknown parameters in the system dynamics and arbitrary constant coupling time delays. By introducing the passivity-based framework, we demonstrate that state consensus is still reachable in this case. Finally, a numerical example is included to illustrate the obtained results.
Zhong Hai,Zhang Wenshuang,Sun Shicheng,Bie Yifan 대한영상의학회 2022 Korean Journal of Radiology Vol.23 No.8
Objective: To determine the anatomical characteristics of the petrous ridge and trigeminal nerve in trigeminal neuralgia (TN) without neurovascular compression (NVC). Materials and Methods: From May 2017 to March 2021, 66 patients (49 female and 17 male; mean age ± standard deviation [SD], 56.8 ± 13.3 years) with TN without NVC and 57 controls (46 female and 11 male; 52.0 ± 15.6 years) were enrolled. The angle of the petrous ridge (APR) and angle of the trigeminal nerve (ATN) were measured using magnetic resonance imaging with a high-resolution three-dimensional T2 sequence. Data on the symptomatic side were compared with those on the asymptomatic side in patients and with the mean measurements of the bilateral sides in controls. Receiver operating characteristic (ROC) analysis was conducted to evaluate the performance of APR and ATN in distinguishing TN patients from controls. Results: In TN patients without NVC, the mean ± standard deviation (SD) of APR on the symptomatic side (98.40° ± 19.75°) was significantly smaller than that of the asymptomatic side (105.59° ± 22.45°, p = 0.019) and controls (108.44° ± 15.98°, p = 0.003). The mean ATN ± SD on the symptomatic side (144.41° ± 8.92°) was significantly smaller than that of the asymptomatic side (149.67° ± 8.09°, p = 0.003) and controls (150.45° ± 8.48°, p = 0.001). The area under the ROC curve for distinguishing TN patients from controls was 0.673 (95% confidence interval [CI]: 0.579–0.758) for APR and 0.700 (CI: 0.607–0.782) for ATN. The sensitivity and specificity using the diagnostic cutoff yielding the highest Youden index were 81.8% (54/66) and 49.1% (28/57), respectively, for APR (with a cutoff score of 94.30°) and 65.2% (43/66) and 66.7% (38/57), respectively, for ATN (cutoff score, 148.25°). Conclusion: In patients with TN without NVC, APR and ATN were smaller than those in controls, which may explain the potential cause of TN and provide additional information for diagnosis.
Role of silibinin in the management of diabetes mellitus and its complications
Chun Chu,Da-Hong Li,Shicheng Zhang,Takashi Ikejima,Ying Jia,Dongkai Wang,Fanxing Xu 대한약학회 2018 Archives of Pharmacal Research Vol.41 No.8
Diabetes mellitus is globally approaching epidemicproportions and acts as a major cause of a number ofserious health problems diagnosed as diabetic complications. The current oral drugs in the treatment of diabetesand its complications could meet some but not all of thepatients’ needs, and the development of novel drugs with ahypoglycemic effect is urgently required. Silibinin, aflavonolignan traditionally used for the treatment of gallbladderand hepatic diseases, was reported to improveglycemic homeostasis by improving the activity of pancreaticb-cells, increasing insulin sensitivity of liver andmuscle cells, and decreasing lipid deposition in adipocytes. Researches also indicated the effectiveness of silibinin incontrolling several diabetic complications including neuropathy,retinopathy, impaired healing, hepatopathy, cardiomyopathy,nephropathy, and osteoporosis. In thisreview, we summarize the recent anti-diabetes findings ofsilibinin and clarify the underlying pharmacologicalmechanisms, and update the knowledge in understandingthe role of silibinin in control of diabetic complications.