1.Study on Chaotic Detection Method of Pacemaker Contact-Less Power Supply.
Chenghu ZHOU ; Mingming HUANG ; Songtao LI
Journal of Biomedical Engineering 2015;32(6):1335-1342
In order to improve the reliability of cardiac pacemaker contact-less power supply technology, this paper proposes a novel application of wireless feedback voltage stabilizing technology to adjust heart disease patients with inner power supply filter circuit output voltage and current control method, to keep the output voltage stability, and to ensure that the super capacitor and cardiac pacemaker to get a stable power supply. To implement the real-time accurate voltage control with considering the primary and secondary side inductance coupling coefficient changes, the change of the external power supply voltage and load, it is necessary to test thee real-time and accurate output voltage and current value after rectifying filtering. Therefore, based on the chaotic control theory, we adopted method of phase diagram on the basis of the quick observation after rectifying filtering, so that the method of voltage and current could improve the detection time of the circuit. The phase diagram of proposed control method can be divided into 8 segments, and we got 7 zero-extreme points. When these zero-extreme points are detected, according to extreme points of the zero instantaneous values, the corresponding average values of voltage and current were obtained. Simulation and experimental results showed that using the above method can shorten the response time to less than switch devices 1/2 switching cycles, thus validating the effectiveness and feasibility of the proposed detection algorithm.
Algorithms
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Electric Power Supplies
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Feedback
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Humans
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Nonlinear Dynamics
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Pacemaker, Artificial
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Wireless Technology
2.Effect of shRNA inhibiting hTERT gene expression combined with γ-irradiation on human laryngeal cancer cells
Liu HU ; Fuxiang ZHOU ; Han LEI ; Ximei ZHANG ; Huibing QIU ; Jing DAI ; Chenghu HUANG ; Conghua XIE ; Shiquan LIU ; Yunfeng ZHOU
Chinese Journal of Radiological Medicine and Protection 2009;29(3):253-258
Objective To construct an eukaryotic expression vector of human telomerase reverso transcriptase (hTERT) gene specific shRNA, and investigate the effect of pshRNA-hTERT combined with γ-irradiation on telomerase activity and DNA damage. Methods The recombinant expression plasmid pshRNA-hTERT was constructed and transfected into Hep-2 cells. The telomerase activity was examined by the PCR-hased telomeric repeat amplification protocol (TRAP). DNA single-stranded break (SSB) and the DNA double-stranded break (DSB) were detected by Comet assay. The xenograft model of human laryngeal carcinoma with the same genetic background and different radiosensitivity (Hep-2 and Hep-2R) was established in nude mice. The mixture of pshRNA-hTERT and liposome was injected to the transplanted tumor to observe the inhibition of the tumor growth. The cell apoptosis was detected by TUNEL. The hTERT protein expression was determined by streptavidin-peroxidase conjugated method (AP). Results Recombinant expression plasmid pshRNA-hTERT was successfully constructed and transfected into Hep-2 cells. The hTERT expression inhibition rate reached 60.78 %. pshRNA-hTERT not only inhibited telomerase activity of Hep-2 inehiding the increase of telomerase activity induced by γ-irradiation, but also inhibited the repair of the SSB and DSB induced by irradiation in the human laryngeal carcinoma xenograft in nude mice with the same genetic background and different radiosensitivity. The pshRNA-hTERT combined with γ-irradiation could inhibit the growth of transplanted tumor (Hep-2: EPO = 1.79; Hep-2R: EPO = 2.01) with reduced telomerase activity and hTERT protein expression. Conclusions The eukaryotic expression vector pshRNA-hTERT could enhance the radiosensitivity of Hep-2 cells in vitro and the human laryngeal carcinoma xenograft in nude mice which had the same genetic background with different radiosensitivity.