The automatic gain control circuit is designed on the basis of MSP430F149 microcomputer with the chopper amplifier, and then continuous stepless regulation of pulse wave signal is fulfilled. Thus individual variation -induced problems are eliminated such as signal baseline drift and saturation. With this circuit, medical instruments can be portable and low-power-consumption.

Ultrasonic sensors are optimal to the guidance system for the blind.The previous ultrasonic guidance systems acquire the position information of obstacles,and transform it into audio signal or tactile vibration.The system developed in this paper,utilizing programmable gain technique and digital potentiometer,acquires the power of reflected ultrasonic as additional information,and informs the blind with modulated audio signal.In this paper,the studies on programmable gain is described detailed including the hardware structure,the software design and information post processing.

Lives are maintained by enough oxygen.Blood oxygen saturation is one of the important parameters which reflects oxygen concentration in blood.The accurate monitoring of blood oxygen saturation is very important to both physiological research and medical application.At present,dual-wavelength method is widely adopted in noninvasive detection of blood oxygen saturation.Therefore,accurate recognition of peak-to-peak value of pulse waveform is a key process in monitoring blood oxygen saturation.In the paper,LMS self-adaptive arithmetic is applied to processing pulse waveform signal.The ratio of corrective detection is improved by the method.

Objective To study non-invasive measurement of reflectance oxygen saturation.Methods Diffusion theory was used to explain the action of light in tissue and deduce reflectance oxygen saturation formula.Then,Reflectance Oxygen Saturation Detection System based on MSP430 was developed and calibrated.Result The calibration result and calibration curve was ascertained and analyzed.Conclusion The formula for detection and measurement of oxygen saturation is put forward by using Reflectance Oxygen Saturation Detection System.

BACKGROUND: Microglia play an important role in immune surveillance in their quiescent state, but the role of the activated microglia is under discussion. OBJECTIVE: To analyze the mechanism of activated microglia in acute cerebral infarction. METHODS: Totally 96 male Kunming mice were selected and randomly divided into four groups, including transplantation, placebo, blank control and sham operation groups. Permanent occlusion of the middle cerebral artery was performed using suture method in the mice of the transplantation, placebo and blank control groups, followed by injection of microglia suspension via subclavian vein, medium containing the same volume of microglia, and nothing, respectively, at 12 hours after modeling. In the meanwhile, the same amount of microglia suspension was injected into the mice of the sham operation group. The Zea-longa scale and brain-derived neurotrophic factor expression at 12, 24 and 72 hours after modeling, the volume of cerebral infarction and the number of nerve cells positive for microtubule-associated protein-2 at 72 hours after modeling were detected. RESULTS AND CONCLUSION: The Zea-longa scale score was 0 point in the sham operation group, which was significantly lower than that in the other three groups at each time point after modeling (P < 0.01). The Zea-longa scores in the transplantation group were significantly lower than those in the placebo and blank control groups at 24 and 72 hours after transplantation (P < 0.01). The positive expression rate of brain-derived neurotrophic factor in the transplantation group was significantly higher than that in the other three groups after transplantation (P < 0.01). The sham group showed no infarction, while the size of cerebral infarction in the transplantation group was significantly lower than that in the placebo and blank control groups (P < 0.01), and the microtubule-associated protein-2 positive rate was significantly higher than that in the placebo and blank control groups (P < 0.01). These results manifest that the activated microglia can improve the survival rate of nerve cells, promote the recovery of cerebral nerve function and reduce the size of cerebral infarction.

Objective To evaluate the left ventricular rotation and twist in the cardiac allograft by speckle tracking echocardiography.Methods Twenty-six heart transplant recipients underwent echocardiographic studies at 1st,3rd,6th and 12th month after heart transplantation.Twenty-six healthy subjects served as controls.Parasternal basal and apical short-axis images of left ventricle were recorded and then were analyzed using EchoPAC software.The curves of basal and apical rotation and left ventricular twist were obtained,Peak values of basal and apical rotation and left ventricular twist were measured and then statistically analyzed.Results There were no significant differences in left ventricular ejection fraction (LVEF) and fractional shortening (LVFS) between heart transplant recipients and controls (P ＞0.05).The left ventricular twist,apical rotation were significantly lower in heart transplant recipients at 1 st,3rd,6th and 12th month after surgery than those in controls (P ＜0.05) ;while basal rotation in heart transplant recipients had no significant difference when compared with controls (P ＞0.05).The left ventricular twist,apical and basal rotation in heart transplant recipients among 1 st,3rd,6th and 12th month after surgery had no significant difference (P ＞ 0.05).Conclusions Although the LVEF and LVFS of cardiac allograft seemed normal,the left ventricular twist,apical rotation were still significantly lower in heart transplant recipients than those in controls.Speckle tracking echocardiography can be used for accurate assessment of left ventricular twist in heart transplant recipients.

Animals ; HSP70 Heat-Shock Proteins ; metabolism ; Male ; Physical Conditioning, Animal ; Physical Endurance ; physiology ; Quadriceps Muscle ; metabolism ; physiology ; Rats ; Rats, Sprague-Dawley ; Vascular Endothelial Growth Factor A ; metabolism

Objective To discuss the surgery procedure and treatment effect of reconstruction of the soft tissue of the thumb/finger defects by the second toe tibial toe pulp skin flap. Methods Ten patients with the soft tissue of pulp of the thumb/finger defects were treat by the same side of the second toe tibial toe pulp skin flap, all the patients have the soft tissue defect of finger pulp with exposed phalanx. Crush them in 4 cases, the machine cut wound in 6 cases. A fixed 2 cases, delayed operation 3-7d after injury to repair in 8 patients. The side of skin flap varied from 2.0 cm × 2.2 cm to 2.0 cm × 3.5 cm. Results Ten fingers in 10 cases all survived. Necrosis in edge part of the shin graft occurred in 2 cases, which was healed through changing of dressing. All cases were followed form 4 months to 16 months. The blood-supply, texture and elasticity of transferred flaps and the shape of fingers pulp were excellent. Good function recovery of the fingers was achieved. Pain and temperature sence were regained. Two point discrimination of the finger pulp was 5-9 mm.Primary healing occurred in all cases. It did not disturb dressing shoes and walking. Conclusion It is a reliable approach for soft-tissue coverage of the thumb/finger using the second toe tibial toe pulp skin flap based on distal perforators of digital artery or ulnar artery. The advantages include simply procedures, reliable blood supply without sacrificing main aneries and possibilities of sensoly recovery.

Objective To explore the value of CT diagnosis of high altitude pulmonary edema (HAPE). Methods The CT findings in 16 patients unfit to high altitude were analyzed. Results The findings on CT were as follows: (1) The early stage of HAPE showed ground glass opacity, most of which located at the superior segment and posterior basis segment of inferior lobes, with the right lung to occur earlier than that of the left lung. (2)The advanced stage showed shaggy opacity. (3) The late stage lesions developed to posterior and apical segment of the superior lobes, air bronchus sign could be seen on involved segments. (4)Right lung was more serious than left lung. Conclusion CT was an ideal method to find HAPE. The accuracy of CT diagnosis in HAPE was 100%.

Objective To evaluate the value of CT guided percutaneous lumbar diskectomy (CT PLD) at plateau area. Methods Sixty eight cases of lumbar disc herniation was reated with CT PLD. (1)Before operation, diseased intervertebral disc was scanned, cases were selected, and operation plan was plotted . (2)The best puncture arrangement was chosen on the current video CT picture by designing the puncture path, noting down the puncture parameter, and marking the puncture spot on patient′s body surface. (3)Puncture was performed according to fixed parameter. (4)Operation was performed after the puncture needle was put into the disc ascertained by scan.(5)CT scan was done again after operation to observe if the puncture path had bleeding and intervertebral disc recovery. Results After 3 to 18 months′ follow up, 28 cases were prominent effective and 36 cases effective. The lumbar disc backed 1 to 4 mm. The total effective rate was 94.12%. Conclusion CT PLD is an ideal therapeutic method for lumbar disc herniation at plateau area because it is safe and effective and with less complications.