The digital music editor software "Cool Edit Pro 2.0" is used to design a virtual hearing testing system. This system has following advantages. First, its signal frequency can be set at will. Second, its dynamic range of signal intensity can reach up to 80dB. Third, the measuring accuracy of decibel value may reach 0.1dB. Forth, the system can be used in single and dual channel measurements. Last but not least, it can carry on data processing and drawing along with the same computer.
Audiometry ; instrumentation ; Computers ; Hearing Tests ; instrumentation ; Music ; Signal Processing, Computer-Assisted ; Software ; User-Computer Interface

OBJECTIVETo investigate the protective effects of selenium on rat hippocampal neurons against ischemia-reperfusion (IR) injury.

METHODSThirty-two rats were randomly divided into sham-operated group, IR group and selenium-treated group, and in the latter two groups, cerebral IR injury was induced by middle cerebral artery occlusion; Na2SeO3 treatment was administer in selenium-treated group. At 14 days after reperfusion, the brain tissues were harvested from the rats and hippocampal neuron injuries were observed by TUNEL and Methylene Blue staining. The levels of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and nerve growth factor (NGF) in the hippocampal tissues were measured by ELISA.

RESULTSCompared with IR group, the rats in selenium-treated group showed no significant increase in the expression of m-NGF (P>0.05), but pro-NGF expression was significantly increased (P<0.05) in the hippocampal tissue. Na2SeO3 treatment significantly inhibited the expressions of TNF-α and IL-1β and decreased the apoptosis of hippocampal neurons following cerebral IR injury (P<0.05).

CONCLUSIONSelenium produces antiapoptotic effect to protect the hippocampal neurons following cerebral IR injury possibly not by increasing the level of m-NGF but by decreasing the expressions of the inflammatory factors.

Animals ; Apoptosis ; Brain Ischemia ; metabolism ; pathology ; Hippocampus ; cytology ; metabolism ; pathology ; Interleukin-1beta ; metabolism ; Male ; Nerve Growth Factor ; metabolism ; Neurons ; drug effects ; metabolism ; pathology ; Rats ; Rats, Sprague-Dawley ; Reperfusion Injury ; metabolism ; pathology ; Sodium Selenite ; pharmacology ; Tumor Necrosis Factor-alpha ; metabolism

Objective To investigate the acute effect of local vibration stimulus with low frequency on hand control ability, flexibility, grip strength, and muscle EMG activity. Methods 10 subjects in this study held a vibrator for 20 seconds with isometric contraction at the vibration frequency of 12.5 Hz (vibration group, VIB) or with only isometric contraction (control group, CON). The same procedure measurement, including control ability, flexibility, grip strength, and muscle activity, were recorded both at pre-stimulus (pre-test) and 60-second after stimulus (post-test), respectively. Paired-t test was used to compare the values between pre-test and post-test and the changing rate between groups. Results The control ability and flexibility in pre-post test showed significant improvement after VIB intervention in VIB (P＜0.05). The changing rate of grip strength and EMG in VIB was significantly higher than those in CON (P＜0.05). Conclusions Acute local vibration stimulus with low frequency can be used to improve the hand control ability and flexibility for those who need better hand functional ability in the future.