居住于海拔3680m高原青年人PWC170做功前后血流动力学观察

目的探讨居住于海拔3680m高原1年青年人PWC170做功前后血流动力学改变。方法将居住于海拔3680m高原1年的24名青年在PWC170做功前后检测血流动力学,用t检验作对比观察。结果主动脉排空系数做功后较做功前增高(P<0.05),心率总周围阻力、肺动脉楔压明显增高(P<0.01)每搏心搏量降低(P<0.05),平均动脉压、冠状动脉灌注压,有效血容量、全血粘度、微循环半更新时间明显降低(P<0.001)。结论高原人体PWC170做功对血流动力的影响较大,这也可能是高原劳动能力降低的重要原因之一。

术前肾功能损伤患者肝移植术后无钙调磷酸酶抑制剂的免疫抑制方案:PATRON07研究结果

鉴于肝移植术前伴有肾功能损伤的患者和高Meld评分患者数量的日益增加,德国学者开展了一项单盲、前瞻性临床研究（PATRON07研究,NCT00604357）,对术前存在肾功能损伤的患者肝移植术后应用无钙调磷酸酶抑制剂（CNI）的免疫抑制剂方案（麦考酚酯MMF＋激素＋巴利昔单抗）,术后稍晚加用西罗莫司。主要研究终点为以肝移植术后30天内耐激素排斥反应发生率评价免疫安全性。

感染性心内膜炎术后并发急性肾功能损伤综合护理1例

感染性心内膜炎是临床发生率和死亡率较高的一种感染性疾病,大部分患者通过手术治疗感染性心内膜炎。据有关资料显示[1],术前肾功能异常是影响患者术后预后的主要因素。相比于其他心脏手术,感染性心内膜炎患者术前肾功能不全一般表现多为栓塞及感染等诸多因素导致的急性肾损伤。

轻度术前肾功能不全是冠状动脉搭桥术后远期临床预后的预测因素

Renal dysfunction is a prognostic marker in patients with cardiovascular disease. However, no long-term follow-up studies on the influence of mild renal dysfunction on mortality in patients undergoing coronary bypass grafting have been reported. Therefore, we aimed to identify the significance of preoperative(mild) renal dysfunction as a long-term predictor of clinical outcome after coronary bypass surgery. In 358 patients who underwent isolated saphenous vein aorta-coronary artery bypass grafting, estimated glomerular filtration rates were calculated with the Cockroft-Gault equation(GFRc). Patients were categorized into 2 groups(group 1, GFRc >71.1 mL·min·1.73 m-2; group 2, GFRc< 71.1 mL·min·1.73 m-2). Multivariate Cox proportional hazard analyses were performed to determine the independent prognostic value of GFRc. During a median follow-up of 18.2 years, 233 patients(65.1%) died. Patients who died had lower GFRc and were older. Multivariate analysis demonstrated that total mortality in patients with lower GFRc was significantly increased(lower GFRc group vs normal GFRc group: hazard ratio, 1.44; P=. 019). Lower GFRc was also an independent predictor of cardiac mortality(hazard ratio, 1.51; P=. 032). No significant differences were observed between groups in the occurrence of myocardial infarction and the need for reintervention. Our study demonstrates that after long-term follow-up, preoperative mild renal dysfunction is an independent predictor of long-term(cardiac) mortality in patients who undergo coronary artery bypass grafting.

Right heart modified myocardial performance index and ductus venosus spectrum parameters in pre-eclampsia fetuses for predicting adverse pregnancy outcomes

Objective To observe the values of changes of right heart modified myocardial performance index(Mod-MPI)and ductus venosus(DV)spectrum parameters in pre-eclampsia fetuses for predicting adverse pregnancy outcomes.Methods Eighty-one pregnant women diagnosed as pre-eclampsia were prospectively enrolled and divided into severe pre-eclampsia(SPE)group(n=39)and mild pre-eclampsia(MPE)group(n=42),while 85 healthy pregnant women were taken as controls(control group).Fetal right heart function parameters,including right ventricular isovolumetric relaxation time(IRT),isovolumetric contraction time(ICT),ejection time(ET),total spent time(TST),Mod-MPI,tricuspid valve peak flow velocity ratio in early and late diastole(TV-E/A),as well as blood flow velocities in each waveform of DV spectrum(S,V,D,and A wave)were obtained,and the pulsatility index(PI)and the ratio of blood flow velocities in each waveform of the DV(S/V,S/D,S/A,V/D,V/A,D/A)were calculated.Intrauterine fetal distress,preterm delivery,neonatal asphyxia and newborn with low weight were considered as adverse pregnancy outcomes.The correlations of right heart Mod-MPI and TV-E/A with DV parameters in pre-eclampsia fetuses were assessed,and their predictive efficacies for adverse pregnancy outcomes were evaluated for right heart Mod-MPI and DV using the receiver operating characteristics(ROC)and the area under the curves(AUC).Results Compared with control group and MPE group,fetal right heart IRT,ICT and Mod-MPI increased and ET decreased in SPE group(all P<0.05).No significant differences of right heart TST and TV-E/A among 3 groups(both P>0.05).Fetal DV A-wave velocity and V/D values progressively decreased but PI progressively increased in control,MPE and SPE groups(all P<0.05).Fetal right heart Mod-MPI in pre-eclampsia was moderately positively correlated with DV PI(r=0.637,P=0.016),while TV-E/A was weakly negatively correlated with DV V/D(r=-0.355,P=0.043).Adverse pregnancy outcomes were noticed in 59 pre-eclampsia cases.The AUC of fetal right heart Mod-MPI and DV PI for predicting adverse pregnancy outcomes in pre-eclampsia cases was 0.897 and 0.848,respectively,without significant difference(Z=0.460,P=0.400).Conclusion Changes of right heart Mod-MPI and DV spectrum parameters in pre-eclampsia fetuses had high value for predicting adverse pregnancy outcomes.

Design of an Analog Front End for Passive UHF RFID Transponder IC

This paper introduces a high-performance analog front end for a passive UHF RFID transponder IC, which is compatible with the ISO/IEC 18000-6B standard,operating at the 915MHz ISM band with a total supply current consumption less than 8μA. There are no external components, except for the antenna. The passive IC＇s power supply is taken from the energy of the received RF electromagnetic field with the help of a Schottky diode rectifier. The RFID analog front end includes a local oscillator, clock generator, power on reset circuit, matching network and backscatter,rectifier,regulator, and AM demodulator. The IC, whose reading distance is more than 3m,is fabricated with a Chartered 0.35μm two-poly four-metal CMOS process with Schottky diodes and is EEPROM supported. The core size is 300μm × 720μm.

Capability matchmaking of semantic web services with preconditions and effects

In order to solve the problem that the current matchmaking methods for semantic web service mainly focus on the matchmaking of IO （inputs, outputs） descriptions which may result in one-sidedness, a description-logic-based IOPE （inputs, outputs, preconditions, effects） description and matchmaking method is proposed for semantic web service. The description logic concept is used to annotate service IO and the description logic assertion is employed to describe service PE（preconditions, effects）. TBox subsumption checking is used to measure the subsumption relationship between IO descriptions of service request and advertising; ABox consistency checking is used for checking the logical implication between PE descriptions of service request and advertising. Based upon the logical implication, four kinds of PE matching degrees are proposed to measure and compare the pros and cons of the results of matchmaking. They are the exact, perfect, side-effect and common match. Experiments show that the method has a higher precision rate under the same recall rate compared with the existing method.

Design and Analysis of Analog Front-End of Passive RFID Transponders

An analog front-end of HF passive RFID transponders compatible with ISO/IEC 18000-3 is presented.Design considerations, especially the power transmission in the RFID transponder, are analyzed. Based on these considerations,an analog front-end is presented with novel architecture, high power conversion efficiency, low voltage, low power consumption, and high performance in an environment of noise and power fluctuation. The circuit is implemented in a Chartered 0.35μm standard CMOS process. The experimental results show that the chip can satisfy the design target well.

Behavioral modeling of RF power amplifiers with time-delay feed-forward neural networks

A novel behavioral model using three-layer time-delay feed-forward neural networks （TDFFNN）is adopted to model radio frequency （RF）power amplifiers exhibiting memory nonlinearities. In order to extract the parameters, the back- propagation algorithm is applied to train the proposed neural networks. The proposed model is verified by the typical odd- order-only memory polynomial model in simulation, and the performance is compared with different numbers of taped delay lines（TDLs） and perceptrons of the hidden layer. For validating the TDFFNN model by experiments, a digital test bench is set up to collect input and output data of power amplifiers at a 60 × 10^6 sample/s sampling rate. The 3.75 MHz 16-QAM signal generated in the vector signal generator（VSG） is chosen as the input signal, when measuring the dynamic AM/AM and AM/PM characteristics of power amplifiers. By comparisons and analyses, the presented model provides a good performance in convergence, accuracy and efficiency, which is approved by simulation results and experimental results in the time domain and frequency domain.

Analysis and Design of a Low-Cost RFID Tag Analog Front-End

A new,low-cost RFID tag analog front-end compatible with ISO 14443A and ISO 14443B is presented. By substituting conventional multi-circle antenna with single-circle antenna, the package cost of the tag is greatly reduced. Based on this exasperate antenna performance,a new rectifier with high power conversion efficiency and low turn-on voltage is presented. The circuit is implemented in an SMIC 0.18μm EEPROM process. Measurement results show that with a 120kΩ load,the power conversion efficiency reaches as high as 36%. For a sinusoidal wave with magnitude of 0. 5V, the output DC voltage reaches IV,which is high enough for RFID tags. The read distance is as far as 22cm.

Influences of enteral nutrition combined with probiotics on gut microflora and barrier function of rats with abdominal infection

AIM： To investigate the influences of enteral, parenteral nutrition and probiotics delivered by gut on intestinal microecology, epithelial tight junctions, immune and barrier function of rats with abdominal infection. METHODS： Rat abdominal infection models established with cecal ligation and perforation method, were divided into three groups： parenteral nutrition （PN group, n = 7）, PN＋enteral nutrition （EN group, n = 7） and PN ＋ EN ＋ probiotics （probiotics group, n = 7） via the needle jejunostomy and neck vein for five days. The total nutritional supplement of the three groups was isonitrogenic and isocaloric. Probiotics was delivered by jejunostomy 10 mL/d （1 x 10^8 cfu/mL）. The rats were killed on the sixth day. The feces in the cecum were cultured for anaerobic bacterial growth and analyzed with bacterial group DNA fingerprint profile with random amplified polymorphic DNA. The transmembrane binding proteins （occludin） and IgA level in plasma cells of intestine epithelium in colon and terminal ileum were measured by an immunohistochemistry method. The ultrastructure of intestinal epithelial tight junctions in colon and small intestine was observed by electronmicroscopy. Vena cava blood and the homogenated tissue of liver, lung and mesenteric lymph nodes were cultured to determine the bacterial translocations, and endotoxin in the blood from portal vein was detected. RESULTS： （1） The amount of bacteria of gut species in EN group and probiotic group was higher than that in PN group. The DNA-proflles in EN group and probiotic group were similar to that of normal rats. The number of DNAprofiles in probiotics group was much more than that in PN group and EN group. Moreover, there were strange stripes in PN group. （2） The expression of occludin and IgA in the small and large intestine in EN group （2.309 ± 0.336, 15.440 ± 2.383） and probiotic group （2.938 ± 0.515, 16.230 ± 3.183） was improved as compared with PN group （1.207 ± 0.587, P 〈 0.05, 11.189 ± 2.108, P 〈 0.01）. The expression of occludin in probiotic group （intestine： 2.93 ± 0.515; cecum： 3.40 ± 0.617） was higher than that in EN group （intestine： 2.309 ± 0.336; cecum： 2.076 ± 0.670; P 〈 0.05）. The expression of IgA, especially in EN group （intestine： 15.440 ± 2.383） and probiotic EN group （large intestine： 12.516 ± 1.542） significantly increased as compared with PN group （intestine： 11.189 ± 2.108; cecum： 10.160 ± 1.643; P 〈 0.01）. The intestinal epithelial tight junctions and microvilli of the probiotic group were more intact than those in the PN group. （3） The bacterial translocations in blood, liver, lung and mesenteric lymph nodes, and the levels of endotoxin were significantly reduced in probiotic （0.082 ± 0.029） and EN （0.125 ± 0.040） groups as compared with PN group （0.403 ± 0.181, P 〈 0.05）. CONCLUSION： Application of EN combined with probiotics could improve the expression of transmembrane binding proteins （occludin） and IgA, correct the intestinal flora disturbance, maintain gut barrier functions and tight junctions, and reduce the occurrence of gut bacterial translocation.

Prealbumin is predictive for postoperative liver insufficiency in patients undergoing liver resection

AIM:To investigate the risk factors for postoperative liver insufficiency in patients with Child-Pugh class A liver function undergoing liver resection.METHODS:A total of 427 consecutive patients undergoing partial hepatectomy from October 2007 to April 2011 at a single center(Department of Hepatic SurgeryⅠ,Eastern Hepatobiliary Surgery Hospital,Shanghai,China) were included in the study.All the patients had preoperative liver function of Child-Pugh class A and were diagnosed as having primary liver cancer by postoperative histopathology.Surgery was performed by the same team and hepatic resection was carried out by a clamp crushing method.A clamp/unclamp time of 15 min/5 min was adopted for hepatic inflow occlusion.Patients' records of demographic variables,intraoperative parameters,pathological findings and laboratory test results were reviewed.Postoperative liver insufficiency and failure were defined as prolonged hyperbilirubinemia unrelated to biliary obstruction or leak,clinically apparent ascites,prolonged coagulopathy requiring frozen fresh plasma,and/or hepatic encephalopathy.The incidence of postoperative liver insufficiency or liver failure was observed and the attributing risk factors were analyzed.A multivariate analysis was conducted to determine the independent predictive factors.RESULTS:Among the 427 patients,there were 362 males and 65 females,with a mean age of 51.1 ± 10.4 years.Most patients(86.4%) had a background of viral hepatitis and 234(54.8%) patients had liver cirrhosis.Indications for partial hepatectomy included hepatocellular carcinoma(391 patients),intrahepatic cholangiocarcinoma(31 patients) and a combination of both(5 patients).Hepatic resections of ≤ 3 and ≥ 4 liver segments were performed in 358(83.8%) and 69(16.2%) patients,respectively.Seventeen(4.0%) patients developed liver insufficiency after hepatectomy,of whom 10 patients manifested as prolonged hyperbilirubinemia unrelated to biliary obstruction or leak,6 patients had clinically apparent ascites and prolonged coagulopathy,1 patient had hepatic encephalopathy and died on day 21 after surgery.On univariate analysis,age ≥ 60 years and prealbumin < 170 mg/dL were found to be significantly correlated with postoperative liver insufficiency(P = 0.045 and P = 0.009,respectively).There was no statistical difference in postoperative liver insufficiency between patients with or without hepatitis,liver cirrhosis and esophagogastric varices.Intraoperative parameters(type of resection,inflow blood occlusion time,blood loss and blood transfusion) and laboratory test results were not associated with postoperative liver insufficiency either.Age ≥ 60 years and prealbumin < 170 mg/dL were selected on multivariate analysis,and only prealbumin < 170 mg/dL remained predictive(hazard ratio,3.192;95%CI:1.185-8.601,P = 0.022).CONCLUSION:Prealbumin serum level is a predictive factor for postoperative liver insufficiency in patients with liver function of Child-Pugh class A undergoing hepatectomy.Since prealbumin is a good marker of nutritional status,the improved nutritional status may decrease the incidence of liver insufficiency.

肾前性肾功能衰竭分期护理

目的探讨肾前性肾功能衰竭分期护理。方法对29例肾前性肾功能衰竭的患者从肾衰前期、少尿期、多尿期、恢复期进行的护理观察,根据护理观察结果积极配合医生治疗,并给与相应的护理措施。结果 29例患者均取得了满意效果。结论肾前性肾功衰竭若能及时抢救、合理治疗、细心的护理观察、给与及时的护理措施,对提高其存活率具有非常重要的作用。

A double closed loop APFC control with feed-forward

In order to improve the steady state performance,dynamic response and power factor of traditional power factor correction(PFC)digital control method and reduce the harmonic distortion of input current,a double closed loop active power factorcorrection(APFC)control method with feed-forward is proposed.Firstly,the small signal model of Boost PFC control systemis built and the system transfer function is deduced,and then the parameters of the main device with Boost topology is estimated.By means of the feed-forward,the system can quickly respond to the change in input voltage.Furthermore,the use ofvoltage loop and current loop can achieve input current and output voltage regulation Simulink modeling shows that this methodcan effectively control the output voltage in case of input voltage largely fluctuating,improve the system dynamic response abilityand input power factor,and reduce the input current harmonic distortion

Multi-functional forward osmosis draw solutes for seawater desalination

Forward osmosis(FO), as one of the emerging desalination technologies, has the potential to produce fresh water from a variety of water sources by utilizing the osmotic pressure gradient across a semi-permeable membrane.Draw solution, as an essential component of any FO process, can extract water molecules from seawater or wastewater. An ideal draw solution should meet three essential requirements, namely high osmotic pressure, low reverse flux, and facile regeneration mechanism. The selection of proper draw solutes is especially critical for an energy-efficient FO process since the energy consumption mostly arises from the separation or regeneration of the draw solution. Recently, we developed a few multi-functional FO draw solutes, mainly aiming to enhance the FO water flux and to explore facile re-concentration methods. This review summarizes these draw solutes,including Na^+_- functionalized carbon quantum dots, thermoresponsive copolymers, hydrophilic magnetic nanoparticles, and thermoresponsive magnetic nanoparticles.

Wavelet network based predistortion method for wideband RF power amplifiers exhibiting memory effects

RF power amplifiers (PAs) are usually considered as memoryless devices in most existing predistortion techniques. Nevertheless, in wideband communication systems, PA memory effects can no longer be ignored and memoryless predistortion cannot linearize PAs effectively. After analyzing PA memory effects, a novel predistortion method based on wavelet networks (WNs) is proposed to linearize wideband RF power amplifiers. A complex wavelet network with tapped delay lines is applied to construct the predistorter and then a complex backpropagation algorithm is developed to train the predistorter parameters. The simulation results show that compared with the previously published feed-forward neural network predistortion method, the proposed method provides faster convergence rate and better performance in reducing out-of-band spectral regrowth.

Effects of Bisoprolol on the ventricular function and hemodynamics in patients with atrial fibrillation and chronic heart failure

Background: Recent data suggest that beta-blockers can be beneficial in patients with chronic heart failure (CHF). Atrial fibrillation (AF) is present in a significant number of patients with CHF and is associateing with significant morbidity and increasing mortality rates. Thus it is necessary to establish therapy to improve the poor prognosis in this high-risk population, but a specific benefit of beta-blockers to the subset with concomitant AF and CHF has been little demonstrated. Objective: To examine the effects of Bisoprolol (6 months treatment) on the ventricular function and hemodynamics in patients with AF and CHF. Methods: 84 patients with stable CHF (NYHA≤Ⅲ class) and AF were assigned to Treated Group( n = 37) or Control group Ⅰ ( n = 22, 24-hour heart mean rate < 70/min) or Control Group Ⅱ ( n = 25, 24-hour heart mean rate ≥ 70/min) . All patients were given the basic therapy for CHF, and Treated Group received Bisopolol. Clinical and echocardiographic variables were measured in 3 groups at baseline and after 6 months, and the results were compared . Results: After 6 months of treatment with Bisoprolol, left ventricular ejection fraction (LVEF) and NYHA class had significandy improved (P < 0.05), and a trend towards a reduction in combined end point of death or CHF hospitalization was also observed (P < 0.20) in Treated Group; The increase of LVEF in Treated Group were associated with a reduction in mitral regurgitation degree and left atrial volume; The heart rate in mean 24-hour and at peak exercise decreased in Treated Group, but were similar to that in Control Group Ⅰ. Conclusion: 6 months of Bisoprolol therapy resulted in an improvement in the NYHA class and LVEF, and also showed a trend towards a reduction in hospitalization or death. The beneficial effects of Bisoprolol on patients with AF and CHF may be partly mediated by improvement of ventricular diastolic function.