This paper discusses some problems must be adverted in the design and application of the PA- series high power amplifier for example as the PA08 and the PA84. It focus in the power supply bypassing, overvoltage protection, current limiting, output protection and the engine installing problems as they are applied in the medical equipment output stage.

Objective To explore the influences of indoor and outdoor sources of air pollutants on NO 2 concentra tions in indoor air.Methods The dynamic variations of NO 2 concentrations in indoor and outdoor air were continuously monitered by ML 9841B chemiluminescence continuous monitoring analyzer in2families of White haven town of west Cumbrra,UK.Results During the period of indoor air monitoring,typical background concentrations of NO 2 in air in the center of White haven were between19and28?g /m 3 (10min-mean),and rose to38-47?g /m 3 (10min-mean)during the morning and evening rush of traffic.NO 2 concentration increased about 190?g /m 3 (10min-mean)after the use of a gas cooker in the kitchen A1-hour mean concentration of253?g /m 3 was recorded in the kitchen air of one of the houses,which substantially exceeded the NAQS standard of200?g /m 3 .Conclusion The increase of NO 2 concentration in kitchen air induced by the use of gas appliances played a more important role in influencing the indoor air quality than outdoor air did.

AIM: To detect surface electromyogram (EMG) signal accurately.METHODS: How to reduce noise in the detection of surface EMG signal was discussed. It has been explored to design an electrode unit by using methods of differential amplification, active electrode, filter and so on , andto investigate the electrode shape and the right placing method.RESULTS: The instrumentation amplifier AD620 was adopted to design a bipolar active electrode, which has been successfully used in the surface EMG detection.CONCLUSION: Experiments show that using active electrode can improve ratio of signal and noise, reduce noise and detect surface EMG signal effectively.

Objective To explore the effect of particulate matter (PM) 2.5 on the expression of pigment epithelium-derived factor (PEDF) protein in bronchial epithelial cells (BEAS-2B). Methods Human BEAS-2B were subcultivated, followed by low, medium and high concentrations of PM2.5 (25μg/ml, 50μg/ml, 100μg/ml) stimulation for 24 hours. The expression of PEDF protein in supernatant was ana-lyzed by enzyme-linked immunosorbent assay (ELISA), and the expression in BEAS-2B cells was detected by Western blotting. Results Compared with the control group, the expression of PEDF protein in supernatant and BEAS-2B cells induced by PM2.5 (25 μg/ml) in-creased, but no significance was found (t=-0.730, t=-1.840, P>0.05), and the expression induced by PM2.5 with the concentrations of 50μg/ml and 100μg/ml significantly increased (t>5.798, P<0.05). Conclusion PM2.5 with the concentrations of 50μg/ml and 100μg/ml could increase the expression of PEDF protein in a concentration-dependent manner both in supernatant and BEAS-2B cells.

Objectives:To learn about the attitudes toward the "Global Minimum Essential Requirements(GMER) in medical education" between Chinese doctors and graduates from the same medical university and to offer reference for spreading GMER in China.Methods: To investigate the subbjects using a questionnaire describing the related abilities of GMER.Description,rank test,multivariate analysis of variance and factor analysis are applied in data analysis.Results: In general,there are different attitudes toward GMER between doctors and graduates.13 of 23 items have statistical significance in scores between groups.The proportion of person considering every item as important or very important among doctors is higher than that among graduates.There is statistical significance between groups on the transformed score in 7 domains of GMER.The domain of topmost score is "clinical skills",and of the lowermost one is "community health & health system".Conclusions: Doctors and graduates both accept GMER.They both pay attention to occupational skills,but ignore the public health.Doctors think much of basic knowledge,while graduates are short of the cognition on "Information Management".

Objective To explore the efficacy and safety of low-dose ketamine for prevention of shivering during cesarean section under subarachnoid space and epidural anesthesia.Methods Ninety pregnant women who scheduled cesarean delivery under subarachnoid space and epidural anesthesia were randomized divided into three groups:control group (30 patients) low-dose ketamine group (30 patients) and high-dose ketamine group (30 patients).0.9％ sodium chloride,0.25 mg/kg(3 ml),and 0.50 mg/kg (3 ml) ketamine were given in three groups before operation.The incidence of shivering and adverse effect were recorded respectively before anesthesia,after anesthesia 15 min and 30 min and after operation 1 h.Results The level of mean arterial pressure (MAP) in control group after anesthesia 15 main and 30 min and after operation 1 h[(62 ± 10),(58 ± 8),(61 ± 11) mm Hg(1 mm Hg =0.133 kPa)] were significantly lower than those in high-dose ketamine group [(78 ± 12),(82 ± 8),(76 ± 11)mm Hg] and low-dose ketamine group [(72 ± 10),(76 ± 6),(80 ± 7) mm Hg],there was significant difference (P ＜ 0.05).There was no shivering need treat in low-dose ketamine group and high-dose ketamine group.The rate of hallucinations and nystagmus in low-dose ketamine group [0,6.7％ (2/30)] was significantly lower than that in high-dose ketamine group [20.0％ (6/30),50.0％ (15/30)],there was significant difference (P ＜ 0.05).Conclusion The pretreatment with low-dose ketamine on shivering during cesarean section under subarachnoid space and epidural anesthesia has better preventive effectiveness,0.25 mg/kg of ketamine is more effective than 0.50mg/kg.

Objective To explore therapeutic effect of dipeptidyl peptidase IV inhibitor on type 2 diabetes mellitus with nonalcoholic fatty liver disease. Methods 120 patients suffering type 2 diabetes mellitus with nonal-coholic fatty liver disease from October 2014 to March 2016 in our hospital were randomly divided into two groups:treatment group and control group. Both groups were given type 2 diabetes conventional treatment ,and the treat-ment group was given dipeptidyl peptidase IV inhibitor in addition. Height,weight,waist circumference,hip cir-cumference were measured. Lipid metabolism and,function index,FPG,2 h PG,HbA1c,Ins,C peptide were detected. HOMA-IR was calculated. Results The total effective rate of clinical treatment of fatty liver in the treat-ment group(88.3%)was higher than the control group(78.3%). The difference was statistically significant. FPG , 2hPG,HbA1c,HOMA-IR,LDL-C,TC,TG,AST,ALT andγ-GT in the treatment group were lower than the con-trol group. The difference was also statistically significant. Conclusion The efficacy of sitagliptin in the treatment of type 2 diabetes with nonalcoholic fatty liver was significant. It can also significantly reduce blood glucose and in-sulin resistance. Furthermore ,it has a better effect on the patients with blood glucose control and lipid metabolism regulation.

Objective　To design and develop a portable multi -parameter life sign monitor. Methods　Electrocardiogram (ECG). blood pressure(BP), breath frequency (BF), heart rate (HR) and body temperature (BT) in real time were recorded with a single-chip microprocessor 8Xc196Mc and a high-resolution (640×200) graphic liquid crystal display (LCD) through sign al detecting and processing techniques. Results　This system cou ld display the ECG wave, and other parameters in real time dynamically. It could also provide a 24 hours trend graph for each parameter measured and exchange th e data through the serial communication interface (RS232) with the PC. C onclusion　This portable monitoring system is capable of performing cont inuous monitoring and also has the capability to resist environmental interferen ce through the added design, so it can be used widely.

OBJECTIVE:To develop a method for the determination of valsartan concentration in human plasma and urine. METHODS:Plasma sample were acidified and extracted with diethyl ether for analysis,and urine sample was diluted directly for analysis. The samples were all determined by LC-MS/MS,and the separation was performed on a Aglient ZORBAX SB-C18 column with mobile phase consisted of acetonitrile and 0.1% formic acid (gradient elution) at flow rate of 0.2 ml/min. Ion transition was determined ESI ion source under multiple ion reaction monitoring with quantitative pair m/z 436.4→253.2 and qualitative ion pair m/z 436.4→291.3 for valsartan,and quantitative pair m/z 423.4→207.1 and m/z 423.4→180.2 for internal standard losartan. RE-SULTS:The linear range of valsartan were 4-5 000 ng/ml in plasma and 20-50 000 ng/ml in urine;the limit of quantification were 4 ng/ml and 20 ng/ml;plasma extraction recovery of valsartan were 61.21%-70.30%. The variation coefficient of internal standard normalized matrix effect were 3.20% and 11.21%. The within-day and between-day RSDs were no more than 8.34%. CONCLU-SIONS:The method is proved to be rapid and sensitive,and suitable for the determination of valsartan in human plasma and urine and pharmacokinetics study.