Relationship between sonographically measured median nerve cross-sectional area and presence of peripheral neuropathy in diabetic subjects

BACKGROUND Neuropathy is a common complication of diabetes mellitus resulting from direct damage by hyperglycemia to the nerves and/or ischemia by microvascular injury to the endoneurial vessels which supply the nerves. Median nerve is one of the peripheral nerves commonly affected in diabetic neuropathy. The median nerve size has been studied in non-Nigerian diabetic populations. In attempt to contribute to existing literature, a study in a Nigerian population is needed.AIM To evaluate the cross-sectional area(CSA) of the median nerve using B-mode ultrasonography(USS) and the presence of peripheral neuropathy(PN) in a cohort of adult diabetic Nigerians.METHODS Demographic and anthropometric data of 85 adult diabetes mellitus(DM) and 85 age-and sex-matched apparently healthy control(HC) subjects were taken. A complete physical examination was performed on all study subjects to determine the presence of PN and modified Michigan Neuropathy Screening Instrument(MNSI) was used to grade its severity. Venous blood was taken from the study subjects for fasting lipid profile(FLP), fasting blood glucose(FBG) and glycated haemoglobin(HbA1 c) while their MN CSA was evaluated at a point 5 cm proximal to(5 cmCATL) and at the carpal tunnel(CATL) by high-resolution Bmode USS. Data was analysed using SPSS version 22.RESULTS The mean MN CSA was significantly thicker in DM subjects compared to the HC at 5 cmCATL(P < 0.01) and at the CATL(P < 0.01) on both sides. The presence of diabetic peripheral neuropathy(DPN) further increased the MN CSA at the CATL(P < 0.05) but not at 5 cmCATL(P > 0.05). However, the severity of DPN had no additional effect on MN CSA 5 cm proximal to and at the CATL. There was no significant association between MN CSA and duration of DM and glycemic control.CONCLUSION Thickening of the MN CSA at 5 cmCATL and CATL is seen in DM. Presence of DPN is associated with worse thickening of the MN CSA at the CATL but not at5 cmCATL. Severity of DPN, duration of DM, and glycemic control had no additional effect on the MN CSA.

Ultrasonographic measurement of median nerve cross-sectional area reference values in a healthy Han population from Guiyang,China

High-resolution ultrasonography was used to analyze the nerve cross-sectional area （CSA） of the median nerve at 7 sites： the wrist crease, pisiform bone, hamate bone, 6 cm proximal to the tip of the wrist crease, proximal forearm （where the nerve enters the pronator teres muscle）, 4 cm proximal to the tip of the medial epicondyle, and mid-humerus （mid-point between elbow crease and axilla） in 200 healthy volunteers from Guiyang, China. Results showed similar CSA values between the left and right sides, but the CSA 6 cm proximal to the tip of the wrist crease, proximal forearm, 4 cm proximal to tip of the medial epicondyle, and mid-humerus in males was greater than that of females. Moreover, CSA values at the wrist crease, pisiform bone, and hamate bone were greater in the middle-aged and old groups when compared to the young group, and correlated with body mass and height. Thus, reference values of median nerve CSA of the upper limbs can facilitate the analysis of abnormal nerve conditions.

Does the ratio of the carpal tunnel inlet and outlet cross-sectional areas in the median nerve reflect carpal tunnel syndrome severity?

Although ultrasound measurements have been used in previous studies on carpal tunnel syndrome to visualize injury to the median nerve, whether such ultrasound data can indicate the severity of carpal tunnel syndrome remains controversial. The cross-sectional areas of the median nerve at the tunnel inlet and outlet can show swelling and compression of the nerve at the carpal. We hypothesized that the ratio of the cross-sectional areas of the median nerve at the carpal tunnel inlet to outlet accurately reflects the severity of carpal tunnel syndrome. To test this, high-resolution ultrasound with a linear array transducer at 5–17 MHz was used to assess 77 patients with carpal tunnel syndrome. The results showed that the cut-off point for the inlet-to-outlet ratio was 1.14. Significant differences in the inlet-to-outlet ratio were found among patients with mild, moderate, and severe carpal tunnel syndrome. The cut-off point in the ratio of cross-sectional areas of the median nerve was 1.29 between mild and more severe（moderate and severe） carpal tunnel syndrome patients with 64.7% sensitivity and 72.7% specificity. The cut-off point in the ratio of cross-sectional areas of the median nerve was 1.52 between the moderate and severe carpal tunnel syndrome patients with 80.0% sensitivity and 64.7% specificity. These results suggest that the inlet-to-outlet ratio reflected the severity of carpal tunnel syndrome.

Usefulness of the acromioclavicular joint cross-sectional area as a diagnostic image parameter of acromioclavicular osteoarthritis

BACKGROUND Acromioclavicular joint(ACJ)space narrowing has been considered to be an important diagnostic image parameter of ACJ osteoarthritis(ACJO).However,the morphology of the ACJ space is irregular because of osteophyte formation,subchondral irregularity,capsular distention,sclerosis,and erosion.Therefore,we created the ACJ cross-sectional area(ACJCSA)as a new diagnostic image parameter to assess the irregular morphologic changes of the ACJ.AIM To hypothesize that the ACJCSA is a new diagnostic image parameter for ACJO.METHODS ACJ samples were obtained from 35 patients with ACJO and 30 healthy individuals who underwent shoulder magnetic resonance(S-MR)imaging that revealed no evidence of ACJO.Oblique coronal,T2-weighted,fat-suppressed SMR images were acquired at the ACJ level from the two groups.We measured the ACJCSA and the ACJ space width(ACJSW)at the ACJ on the S-MR images using our imaging analysis program.The ACJCSA was measured as the cross-sectional area of the ACJ.The ACJSW was measured as the narrowest point between the acromion and the clavicle.RESULTS The average ACJCSA was 39.88±10.60 mm;in the normal group and 18.80±5.13 mm;in the ACJO group.The mean ACJSW was 3.51±0.58 mm in the normal group and 2.02±0.48 mm in the ACJO group.ACJO individuals had significantly lower ACJCSA and ACJSW than the healthy individuals.Receiver operating characteristic curve analyses demonstrated that the most suitable ACJCSA cutoff score was 26.14 mm^(2),with 91.4%sensitivity and 90.0%specificity.CONCLUSION The optimal ACJSW cutoff score was 2.37 mm,with 88.6%sensitivity and 96.7%specificity.Even though both the ACJCSA and ACJSW were significantly associated with ACJO,the ACJCSA was a more sensitive diagnostic image parameter.

Correlation between current and cross-sectional area of parallel fixed-movable dual electrodes in ESC

Electroslag casting with parallel fixed-movable dual electrodes is a new method for achieving better quality of castings in complex mold cavities.In this work,a mathematical model,y=kx^2+(k+1)x,was established to describe the ideal correlation between the current ratio(y)and the cross-sectional area ratio(x)of the dual electrodes,where k is the filling ratio.Investigation was conducted on the electroslag casting process with dual electrodes of various cross-sectional areas,but at a constant k value.The experimental results indicated that the ideal correlation was obtained at the stable casting stage,and the fitting results were consistent with the experimental results at certain k values.The experimental findings show that better castings can be obtained when the current ratio is greater than 1.536 and the cross-sectional area ratio is greater than 0.5.

Modeling Blood Flow in Veins of Uniform Properties (Giraffe Jugular Vein)

This paper models the giraffe’s jugular veins as a uniform collapsible tube from a rigid skull. The equations governing one-dimensional steady flow through such a tube for various conditions have been developed. The effects of inertial and inclination angles that have not been discussed previously have been included. It has been shown that different flows for a uniform tube (vein) are possible. However, this flow matches that of a jugular vein which is supercritical, and the steady solution has been given by the balance between the driving forces of gravity and the viscous resistance to the flow at the right atrium of the heart must be sub-critical for a fixed right-atrium pressure which means that an elastic jump is required to return the flow to sub-critical from the supercritical flow upstream this type of relationship gives rise to flow limitation at the same time given any right atrium fixed pressure there exists a maximum flow rate which when exceeded the boundary conditions of the flow do not hold boundary conditions at the right atrium are not satisfied hence making the steady flow impossible this mechanism of flow limitation is slightly different from the other one in that causes airways through forced expiration from the observation made it is clearly shown that there is an intravascular pressure difference with a change in height.

Exposed Cross-section of the Archaean Lower Crustin the Shanxi-Hebei-Inner Mongolia Border Region:Problems and Prospects

The Archaean lower crust represented by granulite facies rocks, which is rare in China, is found to be exposed in the Shanxi-Hebei-Inner Mongolia border region. Studies of the regional structure and deformation and metamorphism of the region indicate that there occurred at least two phases of deformation and metamorphism in the region. Early-phase nearly E-W-directed deformational structure is well preserved in the Zhangjiakou-Xuanhua area. Observations of the features of the geological structure from north to south (in the Hengshan metamorphic terrain) have revealed a possible exposed cross-section through the Archaean lower crust. The structure was superimposed by a NE-SW-trending high-temperature ductile shear zone in the Datong area in the late phase, thus reworking the Archaean sequence.

Optimal Minimum Number of CT Slices Required to Measure Cross Sectional Areas of Small Pulmonary Vessels

The cross-sectional area (CSA) of small pulmonary vessels can be quantified by CT, which is a reliable method of evaluating vascular alterations in such vessels. However, the optimal number of slices required for accurate quantitation remains unknown. We evaluated relationships among all slices at 10-mm interval and all slices at 3-cm interval, 6-cm interval, and 3-slices and found the closest correlation (0.939) between all slices at 10-mm intervals and 3-cm intervals. Thus, all slices at 3-cm intervals are suitable for accurately measuring CSA.

不孕患者慢性子宫内膜炎宫腔镜评分系统的构建及验证

目的:探索不孕患者中慢性子宫内膜炎(CE)的临床病理和宫腔镜下高危特征,建立宫腔镜诊断CE的评分系统并评估其价值。方法:对2019年10月1日至12月31日在河北医科大学附属石家庄市妇产医院生殖医学中心行宫腔镜检查和内膜活检的238例不孕患者进行病例对照研究,根据CD138免疫组织化学染色结果分为CE组(73例)和非CE组(165例),使用单因素和二元logistic回归分析筛选CE的独立危险因素,建立宫腔镜评分系统,绘制列线图,分别采用受试者操作特征(ROC)曲线、校准曲线对评分系统进行评价,采用Bootstrap法重抽样进行内部验证。结果:单因素及二元logistic回归分析结果显示,充血面积2级及以上、微小息肉、子宫内膜息肉样增生、异位妊娠史是CE的独立危险因素(均P<0.05)。基于上述因素构建的宫腔镜评分系统诊断CE的ROC曲线下面积为0.801(95%CI:0.742~0.861),敏感度为74.0%,特异度为73.9%,表明该系统预测能力中等;校准曲线显示该评分系统的预测值和实际值具有较高的一致性。在内部验证中,C-index指数为0.7811,校准曲线中验证组的预测值和实际值基本一致,表明该评分系统具有较好的稳定性。结论:由充血面积、微小息肉、子宫内膜息肉样增生、异位妊娠史构成的宫腔镜评分系统能有效、简便、直观地预测不孕患者发生CE,有助于完善宫腔镜CE诊断标准,有效弥补组织学诊断不足。

Mulching broad ridges with a woven polypropylene fabric increases the growth and yield of young pear trees ‘Yuluxiang' in the North China Plain

Unlike traditional ridging, mulching broad ridges with a woven polypropylene fabric (WPF) can reduce soil evaporation during the drought season and avoid long saturation time in the root zone of pear trees during the rainy season. In this study, field experiments were conducted from 2017 to 2020 in a pear orchard in the North China Plain to investigate the effects of mulching broad ridges (0.3 m in height and 2 m in width) with WPF on soil temperature and moisture, nitrogen leaching, vegetative and reproductive growth of young pear trees(Pyrus bretschneideri Rehd.‘Yuluxiang’). The experiments involved two treatments, namely, control (traditional no-ridge planting without mulching) and mulching broad ridges with WPF (RM treatment). The results showed that the RM treatment increased soil moisture and temperature and decreased nitrogen leaching, resulting in vigorous growth of the young pear trees. Moreover, the RM treatment increased the tree trunk cross-sectional area and height of the young pear trees by 37%and 8%in 2020, respectively. The nitrate nitrogen content at the soil layer depth of 0-30 cm was significantly higher in the RM than that in control. Furthermore, the RM treatment significantly increased the fruit yield due to larger tree size. In addition, compared with control, significantly higher fruit soluble solid content of RM treatment was detected in 2020. High precipitation (423 mm) occurred during fruit enlargement stage in 2020, RM treatment decreased the rainfall infiltration in the ridge and the soil moisture in root region, resulting in the improvement of fruit quality, compared with control.Therefore, mulching broad ridges with WPF can be implemented to increase soil moisture during drought season, soil temperature, and nitrate nitrogen content, thereby improving the growth and fruit yield of young pear trees. Additionally, it can reduce soil moisture in the root zone during the rainy season and improve the fruit quality of the trees. Finally, it can reduce nitrate nitrogen leaching, thereby reducing environmental pollution.

Eff ects of early standardized enteral nutrition on preventing acute muscle loss in the acute exacerbation of chronic obstructive pulmonary disease patients with mechanical ventilation

BACKGROUND:To investigate the eff ects of early standardized enteral nutrition(EN)on the crosssectional area of erector spine muscle(ESMcsa),plasma growth diff erentiation factor-15(GDF-15),and 28-day mortality of acute exacerbation of chronic obstructive pulmonary disease(AECOPD)patients with invasive mechanical ventilation(MV).METHODS:A total of 97 AECOPD patients with invasive MV were screened in the ICUs of the First People's Hospital of Lianyungang.The conventional EN group(stage Ⅰ)and early standardized EN group(stage Ⅱ)included 46 and 51 patients,respectively.ESMcsa loss and GDF-15 levels on days 1 and 7 of ICU admission and 28-day survival rates were analyzed.RESULTS:On day 7,the ESMcsa of the early standardized EN group was significantly higher than that of the conventional EN group,while the plasma GDF-15 levels were significantly lower than those in the conventional EN group(ESMcsa:28.426±6.130 cm^(2) vs.25.205±6.127 cm^(2);GDF-15:1661.608±558.820 pg/mL vs.2541.000±634.845 pg/mL;all P<0.001).The 28-day survival rates of the patients in the early standardized EN group and conventional EN group were 80.40%and 73.90%,respectively(P=0.406).CONCLUSION:ESMcsa loss in AECOPD patients with MV was correlated with GDF-15 levels,both of which indicated acute muscular atrophy and skeletal muscle dysfunction.Early standardized EN may prevent acute muscle loss and intensive care unit-acquired weakness(ICU-AW)in AECOPD patients.

基于3D-TVS子宫内膜面积成像评估宫腔粘连的新方法

【目的】探讨一种基于经阴道三维超声(3D-TVS)下子宫内膜面积成像评估宫腔粘连(IUA)的新方法。【方法】回顾性分析2017年1月至2018年1月因可疑IUA或者不孕症在我院行宫腔镜检查或者手术的121例患者病史,术前3D-TVS子宫内膜面积大小及手术资料。按照宫腔镜下AFS分期标准对IUA患者进行分期,ROC曲线分析3D-TVS下子宫内膜面积诊断IUA的准确性,Logistic回归分析IUA的影响因素。【结果】根据3D-TVS子宫内膜面积诊断IUA,ROC曲线下面积为0.839,界值点为4.23cm^2,灵敏度为0.86,特异度为0.74,诊断准确率76.03%。根据宫腔镜下IUA的AFS分期,进一步计算不同程度IUA的3D-TVS子宫内膜面积界值点,具体为:轻度IUA(4.02,4.23]cm^2,中度IUA(3.23,4.02]cm^2,重度IUA≤3.23cm2。Logistic回归分析显示:流产孕周每增加一周,IUA的发生率就增加30.6%[OR=1.306,95%CI(1.112-1.532),P=0.001],3D-TVS子宫内膜面积每减少1cm^2,IUA的发生率就增加18.9%[OR=0.189,95%CI(0.079-0.450),P<0.001]。【结论】3D-TVS下子宫内膜面积可以作为一种简单、快速的诊段IUA的指标,并在一定程度上反映IUA的严重程度。

阴道超声测定子宫纵轴切面内膜面积评估子宫内膜容受性的研究

目的:研究超声测定子宫纵切面内膜面积与妊娠结局的关系,并探讨在评估子宫内膜容受性的价值。方法:阴道超声监测国家人口计生委科研所生殖中心520例供精人工授精治疗周期中,人绒毛膜促性腺激素(hCG)日及种植窗日(排卵后7d)子宫纵轴切面内膜面积并各分为4组,观察内膜面积与妊娠结局的关系。结果:hCG日子宫纵轴切面内膜面积明显小于种植窗日;妊娠组hCG日内膜面积与未妊娠组无统计学差异;妊娠组种植窗日内膜面积明显小于未妊娠组;hCG日适合妊娠的内膜面积范围是1.50～<5.5cm2,其中内膜面积1.50～<3.5cm2组妊娠率最高,<1.50cm2及≥5.5cm2无妊娠发生;种植窗日适合妊娠的内膜面积范围是1.50～<6.0cm2,其中内膜面积1.50～<4.50cm2组妊娠率最高,<1.5cm2及≥6.0cm2无妊娠发生。结论:阴道B超监测子宫纵轴切面内膜面积可以为评估内膜的容受性提供简便、直观、无创的超声评价依据。

小鼠月经生理模型的探讨

目的减少Finn CA于1984年首次报道的小鼠月经模型的观察时间点,以期为月经生理学研究提供一种较廉价且易操作的月经模型。方法应用成年雌性去势C57BL/6小鼠,给予续贯性激素处理,最末次激素处理后4～6h,实验组小鼠宫腔内注射花生油以诱导子宫内膜蜕膜化反应,对照组小鼠给予同样激素处理但无宫腔油剂注射。分别于油剂处理后31～35h(T3组)、56～70h(T4组)处死小鼠,称量子宫湿重,制作H&E组织切片,运用图像分析软件CAST2,计算全子宫横截面积(TUA)与子宫内膜横截面积(EA)。结果H&E染色子宫组织切片示在单纯雌激素作用下宫内膜呈单层立方上皮,核浆比较高,内膜基质疏松;雌孕激素联合处理后,分泌细胞易见,腺腔内可见分泌物。激素撤退后实验组T3观察到子宫内膜剥离,T4组示子宫内膜修复。对照组子宫内膜始终完整。子宫湿重在激素撤退后,实验组下降较慢。激素撤退后实验组T3的TUA继续上升而EA则维持原水平,T4组TUA与EA均明显下降。结论此模型在子宫内膜剥落期和早期修复期组织学特征与人类子宫内膜有一定的相似性。

胎盘间充质干细胞对大鼠子宫内膜损伤的修复作用

目的研究胎盘间充质干细胞对大鼠子宫内膜损伤的修复作用。方法 2019年5~11月使用化学损伤法对60只雌性SD大鼠(南京市江宁区青龙山动物繁殖场)构建子宫内膜损伤模型,采用单纯随机抽样分为对照组、凝胶组、模型组,每组各20只。3个动情周期后,每组采用单纯随机抽样抽取10只大鼠行HE染色测量子宫内膜腺体数目、子宫内膜厚度,Masson染色测量子宫内膜纤维化面积百分比。其他30只大鼠与雄鼠合笼,受孕第10天,开腹观察大鼠子宫胚胎个数。结果与对照组比较,模型组子宫内膜腺体数目减少、子宫内膜厚度变薄、子宫内膜纤维化面积百分比升高、受孕大鼠子宫胚胎个数减少,差异有统计学意义(P <0.05)。与模型组比较,凝胶组子宫内膜腺体数目增加、子宫内膜厚度增高、子宫内膜纤维化面积百分比降低,受孕大鼠子宫胚胎个数增多,差异有统计学意义(P <0.05)。与对照组比较,凝胶组子宫内膜腺体数目、子宫内膜厚度无明显变化,差异无统计学意义(P> 0.05);子宫内膜纤维化面积百分比升高,受孕大鼠子宫胚胎个数减少,差异有统计学意义(P <0.05)。结论胎盘间充质干细胞可一定程度地修复损伤的子宫内膜,增加子宫内膜腺体数目、子宫内膜厚度,降低子宫内膜纤维化面积百分比,提高胚胎着床率。

Grey-scale sonography and sonoelastography for diagnosing carpal tunnel syndrome

Carpal tunnel syndrome(CTS) is a common peripheral entrapment neuropathy of the median nerve at wrist level, and is thought to be caused by compression of the median nerve in the carpal tunnel. There is no standard quantitative reference for the diagnosis of CTS. Greyscale sonography and sonoelastography(SEL) have been used as diagnostic tools. The most commonly agreed findings in grey-scale sonography for the diagnosis of CTS is enlargement of the median nerve cross-sectional area(CSA). Several authors have assessed additional parameters. "Delta CSA" is the difference between the proximal median nerve CSA at the pronator quadratus and the maximal CSA within the carpal tunnel. The "CSA ratio" is the ratio of CSA in the carpal tunnel to the CSA at the mid forearm. These additional parameters showed better diagnostic accuracy than CSA measurement alone. Recently, a number of studies have investigated the elasticity of the median nerve using SEL, and have shown that this also has diagnostic value, as it was significantly stiffer in CTS patients compared to healthy volunteers. In this review, we summarize the usefulness of grey-scale sonography and SEL in diagnosing CTS.

Effects of resistance training performed to repetition failure or non-failure on muscular strength and hypertrophy:A systematic review and meta-analysis

Purpose:We aimed to perform a systematic review and meta-analysis of the effects of training to muscle failure or non-failure on muscular strength and hypertrophy.Methods:Meta-analyses of effect sizes(ESs)explored the effects of training to failure vs.non-failure on strength and hypertrophy.Subgroup meta-analyses explored potential moderating effects of variables such as training status(trained vs.untrained),training volume(volume equated vs.volume non-equated),body region(upper vs.lower),exercise selection(multi-vs.single-joint exercises(only for strength)),and study design(independent vs.dependent groups).Results:Fifteen studies were included in the review.All studies included young adults as participants.Meta-analysis indicated no significant difference between the training conditions for muscular strength(ES=-0.09,95%confidence interval(95%CI):-0.22 to 0.05)and for hypertrophy(ES=0.22,95%CI:-0.11 to 0.55).Subgroup analyses that stratified the studies according to body region,exercise selection,or study design showed no significant differences between training conditions.In studies that did not equate training volume between the groups,the analysis showed significant favoring of non-failure training on strength gains(ES=-0.32,95%CI:-0.57 to-0.07).In the subgroup analysis for resistance-trained individuals,the analysis showed a significant effect of training to failure for muscle hypertrophy(ES=0.15,95%CI:0.03-0.26).Conclusion:Training to muscle failure does not seem to be required for gains in strength and muscle size.However,training in this manner does not seem to have detrimental effects on these adaptations,either.More studies should be conducted among older adults and highly trained individuals to improve the generalizability of these findings.

Effect of aerobic exercise on the contractile function of gastrocnemius myosin heavy chain

Objective To study the effect of 4-6 weeks’ treadmill training of male SD rats on the contractile function of their gastrocnemius myosin heavy chain (MHC). Methods Forty male SD rats were randomly divided into control group and training group. The treadmill training of the training group rats was incessantly performed for 4-6 weeks at an intensity of about 75% VO2max (18.5-24 m/min,gradient of 0°,each training session lasting 50 minutes,twice a day). The content of gastrocnemius MHC mRNA was tested by reverse transcription polymerase chain reaction (RT-PCR),and the changes of muscle fibre and its cross-section area (CSA) were measured using immunohistochemistry. Electric stimulation tests were used to determine the maximal tension of isometric contraction of the post-training gastrocnemius. Results ① After continuous treadmill training for 4-6 weeks,we found that the content of the total MHC,MHC Ⅰ,MHC Ⅱx,MHC Ⅱa mRNAs was 105%,105%,109% and 108% of that in the resting control group,respectively,and the MHC Ⅱb mRNA content did not change significantly. The percentage of MHC Ⅰ mRNA in the total MHC mRNA increased while that of MHC Ⅱ mRNA decreased after aerobic training. ② The slow type of fibre type Ⅰ was the main part of the MHC after training and the CSA of the muscle fibres increased simultaneously. ③ The maximal tension of isometric contraction by pulse stimulation of square wave in the training group increased significantly compared with that in the control group (P<0.01). Conclusion The findings indicate that aerobic exercise may promote an increase in the contractile function of MHC.

Ultrasonographic reference values for assessing normal radial nerve ultrasonography in the normal population

High-resolution ultrasound has been used recently to characterize median and ulnar nerves, but is seldom used to characterize radial nerves. The radial nerve is more frequently involved in en- trapment syndromes than the ulnar and median nerves. However, the reference standard for normal radial nerves has not been established. Thus, this study measured the cross-sectional areas of radial nerves of 200 healthy male or female volunteers, aged 18 to 75, using high-resolution ultrasound. The results showed that mean cross-sectional areas of radial nerves at 4 cm upon the lateral epicondyle of the humerus and mid-humerus （midpoint between the elbow crease and axilla） were 5.14± 1.24 and 5.08 ± 1.23 mm2, respectively. The age and the dominant side did not affect the results, but the above-mentioned cross-sectional areas were larger in males （5.31± 1.25 and 5.19 ±1.23 mm2） than in females （4.93 ± 1.21 and 4.93 ± 1.23 mm2, respectively）. In addition, the cross-sectional areas of radial nerves were positively correlated with height and weight （r = 0.38, 0.36, respectively, both P 〈 0.05）. These data provide basic clinical data for the use of high-resolution ultrasound for the future diagnosis, treatment, and prognostic evalua- tion of peripheral neuropathies.

Experiments on self-excited oscillation in a thin-walled collapsible tube

Self-excited oscillation in a collapsible tube is an important phenomenon in physiology. An experimental approach on self-excited oscillation in a thin-walled collapsi- ble tube is developed by using a high transmittance and low Young＇s modulus silicone rubber tube. The elastic tube is manufactured by the method of centrifugal casting in our laboratory. An optical method for recording the evolution of the cross-sectional areas at a certain position along the longitudinal direction of the tube is developed based on the technology of refractive index matching. With the transparent tube, the tube law is measured under the static no-flow condition. The cross section at the middle position of the tube transfers from a quasi-circular configuration to an ellipse, and then to a dumbell-shape as the chamber pressure is increased. During the self-excited oscillation, two periodic self-excited oscillating states and one transitional oscillating state are identified. They all belong to the LU mode. These different oscillating states are related to the initial cross-sectional shape of the tube caused by the difference of the downstream transmural pressure.