Biomedical subjects

Ke-qin Zhang

Publications and source records attributed to Ke-qin Zhang.

3 recordsLinked to original sources

PubMed2006

[The fermentation of 50 kinds of TCMs by Bacillus subtilis and the assay of antibacterial activities of fermented products].

50 Traditional Chinese medicines (TCMs) were fermented by Bacillus subtilis and the antimicrobial activities of the fermented products were assayed against Mycobacterium tuberculosis and Penicillium avellaneum. The results showed that some products of them had stronger antimicrobial activities, but some weaker than the corresponding raw materials, still some had no change, which indicated that microorganism and TCM can effect each other during fermentation.

Anti-Bacterial Agents↗

PubMed2005

[Preliminary screening of specific surface markers of human spermatogonial stem cells].

OBJECTIVE: To explore the specific surface markers for the isolation and purification of human spermatogonial stem cells (SSC). METHODS: Specific markers of human SSC were screened and identified in fetal and adult testes by immunohistochemical assay, using HSC markers c-kit, Thy-1 and human ES integrins. RESULTS: In human adult testes, the alpha6 integrin extensively and significantly expressed on the surface of most of the germ cells in the seminiferous tubule, and beta1 integrin mainly expressed on the surface of the germ cells residing on or near the basal membrane in the seminiferous tubule. Thy-1 scattering expressed on the surface of some cells of the basal membrane, and on some Leydig cells as well. The three antigen markers expressed on the SSC of human adult testes specifically to some extent. SSEA-1 specifically expressed on the surface of the gonocytes in the fetal testes. CONCLUSION: The alpha6 and beta1 integrins and Thy-1 may be used for the SSC isolation as positive markers. SSEA-1 can be used as an identification marker for the fetus SSC.

Adult↗

PubMedDate not supplied

Adaptive terminal sliding mode control for high-order nonlinear dynamic systems.

An adaptive terminal sliding mode control (SMC) technique is proposed to deal with the tracking problem for a class of high-order nonlinear dynamic systems. It is shown that a function augmented sliding hyperplane can be used to develop a new terminal sliding mode for high-order nonlinear systems. A terminal SMC controller based on Lyapunov theory is designed to force the state variables of the closed-loop system to reach and remain on the terminal sliding mode, so that the output tracking error then converges to zero in finite time which can be set arbitrarily. An adaptive mechanism is introduced to estimate the unknown parameters of the upper bounds of system uncertainties. The estimates are then used as controller parameters so that the effects of uncertain dynamics can be eliminated. It is also shown that the stability of the closed-loop system can be guaranteed with the proposed control strategy. The simulation of a numerical example is provided to show the effectiveness of the new method.

Journal Article↗