A comparison of two calibration methods for ultrasonic hydrophones

Although miniature ultrasonic hydrophones are frequently used to measure the acoustic pressure distributions from diagnostic ultrasound sources, relatively little attention has been devoted to the methods for absolute calibration of these hydrophones. In this study a polyvinylidene (PVDF) hydrophone was used to compare two calibration methods currently in use. One is based on a reciprocity technique and the second involves the planar scanning of a source transducer having a known radiated ultrasonic power. The reciprocity method revealed that the hydrophone response did not vary by more than ± 1.6dB from ?262.8dB re 1V/μPa over the frequency range of 1–10 MHz. For the planar scanning technique seven ultrasound sources between 1–10 MHz were used, and all calibration points were within ±0.5 dB of the corresponding points found by the method of reciprocity.     

Neurophysiological methods for the assessment of spasticity: The Hoffmann reflex, the tendon reflex, and the stretch reflex

Purpose: To review the literature concerning neurophysiological methods to assess spasticity with respect to mechanisms and methodology, and to describe the three most commonly used methods: the Hoffmann reflex (H-reflex), the Tendon reflex (T-reflex), and the Stretch Reflex (SR). Method: A systematic internet database search was performed to identify neurophysiological measurement methods of spasticity. A systematic exclusion procedure resulted in 185 included references, completed by additional informal search. For this paper, information about the H-, T- and stretch reflexes was extracted from these references. Results: Although the reflexes are basically monosynaptic, there are many supraspinal pathways which modulate the responses in terms of their amplitude and latency. As a consequence the methods are sensitive to a considerable number of experimental conditions and are characterized by a moderate reliability and sensitivity. Correlations with other (i.e. biomechanical, neurophysiological or clinical) spasticity assessment parameters are moderate to poor. Standardised and broadly accepted protocols are still largely lacking preventing an effective exchange of knowledge. Conclusions: The clinical and experimental use of the three methods is restricted due to moderate reliability and sensitivity. It is recommended to perform combined neurophysiological - biomechanical assessment of spasticity during active, functional movement.     

Neurophysiological methods for the assessment of spasticity: The Hoffmann reflex,the tendon reflex,and the stretch reflex

Purpose: To review the literature concerning neurophysiological methods to assess spasticity with respect to mechanisms and methodology, and to describe the three most commonly used methods: the Hoffmann reflex (H-reflex), the Tendon reflex (T-reflex), and the Stretch Reflex (SR). Method: A systematic internet database search was performed to identify neurophysiological measurement methods of spasticity. A systematic exclusion procedure resulted in 185 included references, completed by additional informal search. For this paper, information about the H-, T- and stretch reflexes was extracted from these references. Results: Although the reflexes are basically monosynaptic, there are many supraspinal pathways which modulate the responses in terms of their amplitude and latency. As a consequence the methods are sensitive to a considerable number of experimental conditions and are characterized by a moderate reliability and sensitivity. Correlations with other (i.e. biomechanical, neurophysiological or clinical) spasticity assessment parameters are moderate to poor. Standardised and broadly accepted protocols are still largely lacking preventing an effective exchange of knowledge. Conclusions: The clinical and experimental use of the three methods is restricted due to moderate reliability and sensitivity. It is recommended to perform combined neurophysiological?-?biomechanical assessment of spasticity during active, functional movement.     

脑卒中后抑郁状态与抑郁症患者的多导睡眠图对照研究

目的探讨脑卒中后抑郁状态(PSD)患者的睡眠图异常改变及与抑郁症之间的差异。方法采用多导睡眠图对62例脑卒中和30例抑郁症患者进行整夜睡眠描记,并与对照组比较。结果PSD组与对照组和非抑郁组比较多项睡眠指标均有显著性差异(P<0.05～0.01);PSD组的REM睡眠时间和密度明显低于抑郁症组,差异有显著性(P<0.01)。结论PSD状态病人除具有睡眠障碍在多导睡眠图改变外,REM睡眠时间和密度是一个较为特征性的改变,PSD的发生可能与脑内5-羟色胺(5-TH)递质改变有关。     

抗凝新鲜血在血细胞分析仪校准和比对中的应用探讨

目的探讨用抗凝新鲜血在血细胞分析仪校准和比对的应用价值。方法选择Sysmex TX-2000i血液分析仪为参比仪,迈瑞BC-3000血液分析仪为比对仪。(1)采集体检健康人用乙二胺四乙酸二钾抗凝新鲜血在参比仪按规范的操作方法进行定值,然后用该血液校准比对仪。(2)每天选择无细胞聚集和碎片的新鲜血标本,在参比仪和比对仪分别测试3次并记录均值结果,为期2个月共检测180例标本,采用直线回归分析检验结果的相关性和一致性。结果 (1)比对仪经定值新鲜血校准后其测定结果与参比仪测定结果的偏差比校准前明显降低,差异有统计学意义(P<0.01)。(2)参比仪与比对仪测定结果各参数之间相关密切(r2>0.95),一致性良好。结论利用抗凝新鲜血用于血细胞分析仪的校准和比对,经济有效,可以提高血液分析仪结果的准确性和可比性。     

Ultrasound monitoring of ovarian follicular development: a comparison real-time and static scanning techniques

Follicular growth was monitored in 19 patients during 20 spontaneous and induced cycles by different examiners in a blind trial using a real-time linear array, a mechanical sector scanner, and a gray scale compound scanner. This was done to compare the efficacy of different ultrasound equipment in the study of ovarian cycle. The mean maximum follicular diameter was calculated with each equipment and the quality of follicular images was classified as poor, sufficient, and good as defined in the study. The overall best results in ovary and follicle visualization were achieved with the real-time sector scanner. Measurements of the same dominant follicle using realtime and compound scanners were highly correlated (linear array/compound scanner: r = 0.894, p less than 0.001; sector/compound scanner: r = 0.928, p less than 0.001). Following ovulation, some unexpected differences in the distribution of the postovulatory patterns were noted with each instrument. Except in difficult patients, real-time examination, preferably performed using a sector scanner, appears to be the optimal first ultrasonic approach for monitoring follicular growth.     

A gas mixer for computer calibration of an anesthetic mass spectrometer

To calibrate an anesthetic mass spectrometer without the use of premixed gases and vapors in cylinders, we devised a gas mixer using fixed resistances of capillary needle tubings and adjustable needle valves to dilute test gases and vapors with oxygen. The dilution ratio was determined during each calibration by diluting air with oxygen and noting the reduction in the ratio of nitrogen to oxygen. Empiric correction was made by the computer for the effects of density and viscosity, relative to air, on the flow of nitrous oxide, carbon dioxide, and the saturated vapors of the three anesthetics through the capillary resistor. The computer was programmed to control solenoid valves both for calibration and for the multiplexed sampling of operating rooms. Oxygen, nitrous oxide, and carbon dioxide were used as pure gases, and halothane, enflurane, and isoflurane were vaporized at room temperature in 50-ml vaporizers. The resulting calibrations were found to be accurate to within ±2%.     

两种空气净化机对手术室空气动静态消毒菌落数对比研究

目的比较2种不同消毒机对Ⅱ类手术室空气消毒的效果。方法将两个空间相等、条件基本相同的手术室随机分为观察1组和观察2组,观察1组用新型空气消毒机净之界,观察2组用动态消毒机,分别于消毒1h后于手术前0min,手术开始后20、40、60min做标准5点采样,比较二者的消毒效果。结果两种动态空气净化系统在术前0min,杀菌效果差异无统计学意义（P〉0.05）,在手术开始20、40、60min 3个时间段两组差异有统计学意义（P〈0.01）。结论新型空气消毒机净之界优于动态消毒机消毒效果,同时安全、经济,不产生衍生、次生污染物,值得临床推广使用。     

A Time-Domain Analysis of Intracardiac Electrograms for Arrhythmia Detection

The analysis of intracardiac electrogram morphology has been proposed as a complementary method for accurate discrimination between sinus rhythm (SR), supraventricular dysrhythmias, and ventricular dysrhythmias by automatic antitachycardia and cardioverter defibrillator devices. In this study, the performance of a traditional time-domain method for surface electrocardiogram interpretation—Correlation Waveform Analysis (CWA) and a newly developed technique—Bin Area Method (BAM) were used to analyze unfiltered intraatrial and intraventricular electrograms obtained from 47 patients during routine cardiac electrophysiology studies. Nineteen patients had 31 distinct, sustained, monomorphic ventricular tachycardias (VTs) induced; 13 patients had paroxysmal bundle branch block of supraventricular origin (BBB) induced; 19 patients had retrograde atrial activation during ventricular overdrive pacing. Three patients were common to two or more groups. Using a best fit electrogram alignment, both CWA and BAM distinguished VT from SR in 28/31 cases (90%), BBB from SR in 15/15 patients (100%), and anterograde from retrograde atrial activation in 19/19 patients (100%J. We conclude that the use of time-domain techniques that are independent of amplitude and baseline fluctuations appear to be reliable for discrimination of retrograde atrial activation, paroxysmal BBB, and VT from SR using intracardiac electrograms. Reduction of computational time and power constraints, without sacrificing reliable dysrhythmia discrimination, is possible. These features may make real-time morphology analysis of intracardiac electrograms feasible for automatic antitachycardia and cardioverter-defibrillator devices.     

Metabolomics comparison of cord and peripheral blood-derived serum eye drops for the treatment of dry eye disease

Allogeneic peripheral blood-derived (PBS) serum eye drops have been largely used in the treatment of dry eye disease (DED). Recently, cord blood has emerged as an effective alternative serum source (cord blood serum, CBS), containing a higher amount of growth factors than PBS, it holds the promise of a better capability to stimulate corneal healing. However, the lack of a standardized method for preparation, dispensation, storage and a poor biochemical characterization still hamper the establishment of a clinical consensus. Here the metabolomes of the two different serum eye drop preparations were compared using proton nuclear magnetic resonance spectroscopy. We found that both PBS and CBS contained several organic compounds, the majority of them already detected in human tears and may be thereby considered lacrimal substitutes. Metabolites having in the multivariate statistical analysis Partial least squares discriminant analysis (PLS-DA) a VIP scores > 1.0 were considered to be significantly different. All the metabolites identified were found to have a p < 0.05 in the univariate analysis. CBS, in particular, showed the highest amount of choline, myo-inositol, glutamine, creatine and β-hydroxybutyrate. These evidences constitute relevant advances towards serum eye drops characterization and confirm that cord blood is a valid alternative source of serum eye drops.     

Tracer kinetics analysis of dynamic contrast‐enhanced CT and MR data in patients with squamous cell carcinoma of the upper aerodigestive tract: comparison of the results

Purpose: (i) To evaluate the feasibility of tracer kinetics analysis of dynamic contrast‐enhanced (DCE) CT and T2‐weighted MR data of squamous cell carcinoma (SCCA) of the upper aerodigestive tract. (ii) To compare functional parameters derived by both modalities and examine the interchangeability of them as well as the intra‐ and inter‐rater agreement. Materials and methods: Dynamic contrast‐enhanced‐CT and MR images of 23 patients with SCCA were postprocessed using a distributed‐parameter (DP) tracer kinetic model. The evaluated parameters included blood flow (F), intravascular blood volume (v₁), extravascular extracellular blood volume (v₂), intravascular mean transit time (t₁), lag time (t₀), permeability surface area product (PS) and extraction ratio (E). Mean perfusion values, based on region‐of‐interest analysis, of the tumors and the healthy muscle tissue were compared and correlated. Inter‐rater and intra‐rater variability were assessed. Interchangeability of the tumor functional parameters was tested using Pearson’s correlation coeficients and Bland–Altman plots. Results: The mean values in tumor and healthy muscle tissues were significantly different for each modality (0·0001≤P≤0·03). The mean values of all tumor perfusion parameters apart from v₂ and E were significantly different (0·001≤P≤0·009) between the two modalities. The intra‐rater variability was good to very good for all parameters. The inter‐rater variability was moderate to good. Bland–Altman plots of F, t₁, t₀, and v₂ showed moderate interchangeability. There was a proportionality error in v₁ and PS graphs. Conclusion: The estimation of functional parameters in SCCA is feasible using DCE‐CT and ‐MR with a DP model. The parameters are mostly significantly different and the interchangeability of them is limited.     

A comparison of classroom and distance learning techniques for rural emt-i instruction

Objectives. To determine whether two different distance learning techniques are as effective as classroom teaching for training rural-based emergency medical technician-intermediate (EMT-I) students. Methods. A prospective, nonrandomized comparison of three different instructional methods, with the outcome measurements being mean test scores and attrition rates, was devised. Fifty-seven EMT-I students from rural communities in central Texas were assigned to one of three groups. Each group received 50 hours of didactic instruction based on the U.S. Department of Transportation EMT-I curriculum. The same instructor taught all classes, and all groups used the same workbooks, syllabi, and computer-based tutorials. Group 1 (n = 25) received traditional classroom instruction. Group 2 (n = 18) received instruction using a two-way audio/graphic computer network. Group 3 (n = 14) received instruction using a satellite-based audio/video network. All students then took a standardized multiple-choice examination. Attrition rates were based on the number of those who qualified for EMT-I certification. Results. Mean test results for each group were as follows: group 1, 93 (95% CI = 91-95); group 2,94 (95% CI = 93-96); group 3, 94 (95% CI = 92-96). No significant difference was noted in mean test scores between groups (p = 0.21). Attrition rates were as follows: group 1, 88% (95% CI = 69-97%); group 2,100% (95% CI = 81-100%); group 3, 86% (95% CI = 57-98%). No significant difference was seen in attrition rates between groups (p = 0.24). Conclusions. No difference was found in mean test scores or attrition rates between traditional classroom and two distance learning methods for rural-based EMT-I students. Distance learning techniques may offer an effective alternative for providing educational opportunities to rural EMS providers.     

Sleep-associated movement disorders and the risk of cardiovascular disease: A systematic review and metaanalysis

AIM:To investigate whether an association exists between sleep-associated movement disorders and cardiovascular disease(CVD).METHODS:Several studies have observed the relationship of sleep-associated movement disorders such as restless legs syndrome(RLS)and periodic limb movements during sleep with CVD,but the results were still contradictory.We performed an extensive literature search on Pub Med,Medline and Web of Science published from inception to December 2014.Additional studies were manually searched from bibliographies of retrieved studies.Meta-analyses were conducted with Stata version 12.0(Stata Corp,College Station,Texas).Pooled odds ratios(ORs)and 95%CIs were calculated to assess the strength of association using the random effects model.Sensitivity and subgroup analyses were performed to explore the underlying sources of heterogeneity.The publication bias was detected using Egger’s test and Begg’s test.RESULTS:A total of 781 unique citations were indentified from electronic databases and 13 articles in English were finally selected.Among these studies,nine are cohort studies;two are case-control studies;and two are cross-sectional studies.The results showed that the summary OR of CVD associated with sleepassociated movement was 1.51(95%CI:1.29-1.77)in a random-effects model.There was significant heterogeneity between individual studies(P for heterogeneity=0.005,I2=57.6%).Further analysis revealed that a large-scale cohort study may account for this heterogeneity.A significant association was also found between RLS and CVD(OR=1.54,95%CI:1.24-1.92).In a fixed-effects model,we determined a significant relationship between sleep-associatedmovement disorders and coronary artery disease(CAD)(OR=1.34,95%CI:1.16-1.54;P for heterogeneity=0.210;I2=30.0%).Our meta-analysis suggests that sleep-associated movement disorders are associated with prevalence of CVD and CAD.CONCLUSION:This finding indicates that sleep-associated movement disorders may prove to be predictive of underlying CVD.     

A comparison of two methods for the computer analysis of arterial blood pressure waveforms

Two different methods, one analogue and one digital, for the analysis of the arterial blood pressure waveform are described and compared. Little difference was found in the systolic and diastolic pressures determined by the two methods.     

A prospective sequential analysis of the fear-avoidance model of pain

The primary purpose of this study was to analyze the sequential relationships proposed by the fear-avoidance model of pain [Vlaeyen JWS et al. The role of fear of movement/(re)injury in pain disability. J Occup Rehab 1995;5:235–52]. Specifically, this study evaluated whether early change in catastrophizing predicted late change in fear of movement, and whether these factors influenced post-treatment return-to-work. Secondary analyses tested relationships between (1) early change in catastrophizing, late change in depression, and disability; and (2) early change in catastrophizing, late change in pain severity, and disability. Analyses were conducted on a sample of 121 individuals (82 men and 32 women) with a work-related musculoskeletal injury, and high baseline catastrophizing and fear of movement scores. Participants were enrolled in a 10-week community-based disability management intervention, and they completed measures of catastrophizing, fear of movement, depression and pain severity at pre-, mid- and post-treatment. Return-to-work was assessed 4 weeks following termination of the intervention. Contrary to predictions, results from correlational analyses revealed non-significant relationships among indices of early change in catastrophizing and late changes in fear of movement, depression and pain severity. Multiple logistic regression analyses revealed that early change in catastrophizing, late changes in fear of movement and late change in pain severity were significant predictors of return-to-work, while late changes in depression were not. These findings highlight the importance of reductions in psychosocial risk factors in augmenting return-to-work outcomes. Implications for the fear-avoidance model and future research are discussed.     

人体动态和静态地面反力检测系统的研制

目的：研制一种集成检测动态行走和静态站立的地面反力分析系统。方法：设计三 维测力台检测地面反力，开发数据采集、计算和分析的专用计算机软件。结果：利用该系统不仅可以检测行走过程中三个方向的地面反力，而且可以检测站立时压力中心曲线，计算其动摇长度、面积等特征值。结论：在测试常规行走的三维测力台上增加测试平衡能力的功能，可以丰富设备的功能，提高设备的利用率。     

A Mini-System for Storage, Retrieval and Management of Pacemaker Data

Information processing is becoming a necessity for the management and the analysis of data at Cardiac Electrostimulation Centers, particularly since pacemaker implantation is becoming more frequent and the material more diversified. The mini system described allows retrieving of simple data and allows a real time acquisition of spike parameters by means of an electronic coupling unit with an impulse analyser. Its simplicity, availability and low cost are desirable qualities needed for the proper functioning of a Pacemaker Implantation Center.     

A comparison of two muscle energy techniques for increasing flexibility of the hamstring muscle group

Variations in the application of muscle energy technique (MET) for increasing the extensibility of muscles have been advocated, but little evidence exists to support the relative merit of a particular approach. This study investigated two types of muscle energy techniques that have been advocated in the osteopathic literature that differ primarily in the duration of the post-contraction stretch phase. Forty asymptomatic participants (mean age=22.1±3.5, male female=1:4) were randomly allocated to one of two groups (Group 1: MET with 30-s post-isometric stretch phase; Group 2: MET with 3-s post-isometric stretch phase). Hamstring length was measured using active knee extension (AKE). Participants received an initial application of the allocated intervention, and then a second application 1 week later. Analysis with a split-plot ANOVA revealed a significant effect of time (F_3,36=42.30;p<0.01), but no significant time*group interaction (F_3,36=0.12; p=0.95). Post-hoc analysis revealed that the significant differences over time occurred between pre- and post-measurements at both weeks, and between post-Week 1 and pre-Week 2 measurements.Both techniques appeared to be equally effective in increasing hamstring extensibility, and there appeared to be sustained improvement 1 week following the initial treatment. The findings suggest that altering the duration of the passive stretch component does not have a significant impact on the efficacy of MET for short-term increases in muscle extensibility.