Objective To design an automatic exposure control circuit for X ray equipment to improve the performance of equipment and the quality of film. Methods The device acted in series control. During exposuring process,the X ray reaching the film through patient body was measured by ray sensor. After it was treated with integration, amplification and contrast management,the signal of X ray quantity drived the device to cut off exposure circuit, so that the exposure time was automatic any controlled. Results The effect of the device has been proved by its application in several hospitals. Conclusion The device is simple and effective and has practical value.

Purpose:To study the effect of P14ARF gene on human glioma cell line (U 251) Methods:We transfected P14ARF gene into human malignant glioma cell line with liposomal transfection reagent, we assessed cell growth properties,cell cycle.Results:After successful transfection, the human malignant glioma cell line U 251 proliferation rate was slower. The cell cycle was suppressed at G 1 and G 2.Conclusions:The findings suggest that p14ARF gene may be able to inhibit the growth of glioma cell in vitro.

Objective To compare and analyze the performance indexes and the imaging quality of the home and imported X-ray machines through testing their partial imaging performance parameters. Methods By separate sampling from 10 home and 10 imported X-ray machines, the parameters including tube current, time of exposure, machine total exposure, and repeatability were tested, and the imaging performance was evaluated according to the national standard. Results All the performance indexes met the standard of GB4505-84. The first sampling tests showed the maximum changing coefficient of imaging performance repeatability of the home X-ray machines was ?max1=0.025,while that of the imported X-ray machine was ?max1=0.016. In the second sampling tests, the maximum changing coefficients of the two were ?max2=0.048 and ?max2=0.022, respectively. Conclusion The 2 years′ follow-up tests indicate that there is no significant difference between the above-mentioned parameters of the elaborately adjusted home X-ray machines and imported ones, but the home X-ray machines are no better than the imported X-ray machines in stability and consistency.