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21.
牛英鹏 《北京体育大学学报》2008,31(2):205-207
目的:探索用肌肉超声图(SMG)检测肌肉疲劳变化特征的新方法.方法:用SMG检测受试者肱二头肌做等长收缩至疲劳过程中围度的变化,同步记录表面肌电图(SEMG)信号做为对照,结合肌电信号的均方根(RMS)和中心频率(MDF)变化检测肌肉的疲劳.结果:表面肌电RMS随时间呈线性增加变化(2.9±1.9%/s),而MDF呈线性减少变化(O.60±0.26Hz/s).用超声图检测出肌肉疲劳时厚度呈持续性增加,但与时间不呈线性关系.在起始8.1±2.1s有一个快速增加阶段,平均变化率为0.30±0.19%/s,随后增幅减慢,变化率为0.067±O.024%/s,一直持续到收缩后20s.在肌肉收缩20s时的变化率为3.5±1.6%/S.结论:使用SMG检测肌肉形态结构的变化可为表面肌电评估肌肉疲劳提供有力的补充信息. 相似文献
22.
将超声雾化作用与固相微萃取技术相结合,应用于提取蜂蜜中的挥发性成分,采用GC/MS方法进行分离、鉴定.实验结果表明,DVB/CAR/PDMS萃取纤维头富集出蜂蜜中22种挥发性化合物,且该方法简便快速,无需加热,适用于蜂蜜中挥发性成分的分析. 相似文献
23.
Pawel Linek Pardis Noormohammadpour Mohammad Ali Mansournia Tomasz Wolny Damian Sikora 《运动与健康科学(英文)》2020,9(6):614-619
BackgroundMost papers examining the lateral abdominal muscles (LAMs) and low back pain (LBP) are cross-sectional, with groups of participants being divided into a control and an LBP group. We hypothesized that morphological measurements of the LAMs in adolescent soccer players may predict future LBP incidence. The aim of this study was to examine the associations between the morphology of LAMs and LBP incidence rate among adolescent soccer players.MethodsNinety-seven adolescent male soccer players with no LBP at baseline were recruited into the prospective cohort study. The thickness of the LAMs was measured at baseline by ultrasound imaging in a supine rest position. Nine cases of LBP occurred during the follow-up 6-month observation.ResultsAn obliquus internus (OI) asymmetry was related to increasing LBP risk (odds ratio = 19.99; 95%CI: 2.4–167.9). Spearman correlation also showed a linear relationship between OI asymmetry value and duration of LBP (R = 0.75, p = 0.02). An OI side-to-side difference greater than 1.25 mm suggests possible LBP incidence in the 6-month observation among adolescent soccer players.ConclusionThe morphological changes of the OI may be related to LBP’s incidence in adolescent soccer players. The presence of OI asymmetry increases the odds of LBP by at least 2.4 times. Hypertrophy of the OI on one side of the body may contribute to trunk muscle imbalance. 相似文献
24.
目的：探讨橄榄球运动训练对男大学生跟骨骨密度（BMD）的影响及其意义。方法：采用Osteospace定量超声骨密度仪,对长期从事橄榄球专项训练的男大学生11名（运动组）,沈阳体育学院体育教育系的11名同龄男大学生（运动对照组）和沈阳体育学院非体育专业的10名学生（一般对照组）进行定量超声骨密度测试,测试部位为右脚跟骨。结果：运动组的BUA与运动对照组相比没有显著性差异（p=0．540）,与一般对照组相比具有非常显著性差异（p=0．004,p〈0．01）;运动组的STI与运动对照组相比无显著性差异（p=0．099）,与一般对照组相比差异显著（p=0．031,p〈0．05）;运动对照组的BUA、STI与一般对照组相比均无显著差异（p=0．135;p=0．997）。结论：橄榄球运动能提高骨密度,增加骨量;高力量性训练、高冲击性运动对骨密度具有良好的影响。 相似文献
25.
Incorporation of a tendon graft within the bone tunnel represents a challenging clinical problem. Successful anterior cruciate ligament (ACL) reconstruction requires solid healing of the tendon graft in the bone tunnel. Enhancement of graft healing to bone is important to facilitate early aggressive rehabilitation and a rapid return to pre-injury activity levels. No convenient, effective or inexpensive procedures exist to enhance tendon-bone (T-B) healing after surgery. Low-intensity pulsed ultrasound (LIPUS) improves local blood perfusion and angiogenesis, stimulates cartilage maturation, enhances differentiation and proliferation of osteoblasts, and motivates osteogenic differentiation of mesenchymal stem cells (MSCs), and therefore, appears to be a potential non-invasive tool for T-B healing in early stage of rehabilitation of ACL reconstruction. It is conceivable that LIPUS could be used to stimulate T-B tunnel healing in the home, with the aim of accelerating rehabilitation and an earlier return to normal activities in the near future. The purpose of this review is to demonstrate how LIPUS stimulates T-B healing at the cellular and molecular levels, describe studies in animal models, and provide a future direction for research. 相似文献
26.
C. W. Joseph E. J. Bradshaw T. P. Furness J. Kemp R. A. Clark 《Journal of sports sciences》2016,34(13):1215-1221
Downhill backwards walking causes repeated, cyclical loading of the muscle–tendon unit. The effect this type of repeated loading has on the mechanical behaviour of the Achilles tendon is presently unknown. This study aimed to investigate the biomechanical response of the Achilles tendon aponeurosis complex following a downhill backwards walking protocol. Twenty active males (age: 22.3 ± 3.0 years; mass: 74.7 ± 5.6 kg; height: 1.8 ± 0.7 m) performed 60 min of downhill (8.5°), backwards walking on a treadmill at ?0.67 m · s?1. Data were collected before, immediately post, and 24-, 48- and 168-h post-downhill backwards walking. Achilles tendon aponeurosis elongation, strain and stiffness were measured using ultrasonography. Muscle force decreased immediately post-downhill backward walking (P = 0.019). There were increases in Achilles tendon aponeurosis stiffness at 24-h post-downhill backward walking (307 ± 179.6 N · mm?1, P = 0.004), and decreases in Achilles tendon aponeurosis strain during maximum voluntary contraction at 24 (3.8 ± 1.7%, P = 0.008) and 48 h (3.9 ± 1.8%, P = 0.002) post. Repeated cyclical loading of downhill backwards walking affects the behaviour of the muscle–tendon unit, most likely by altering muscle compliance, and these changes result in tendon stiffness increases. 相似文献
27.
ZHANG Chen-xi CHEN Ya-zhu 《浙江大学学报(A卷英文版)》2007,8(8):1237-1245
A 3D ultrasound thermal model with a 3D finite element representation for modeling the thermal diffusion effects for hepatic ablation induced by spherical-section ultrasound phased array was developed. The model was first validated against available published measured data in rat liver. Using the validated model,effects of blood perfusion and heating schemes on lesion formation were studied for both single focus and split-focus intensity patterns. It was shown that for single focus sonication pattern the short-duration(～2 s) and high-intensity(～1250 W/cm2) heating scheme can completely reduce the cooling effect of the blood perfusion. The lesion shape and size were significantly altered by perfusion for split-focus pattern even with a rapid heating scheme when the focus spacing was larger than 2.4 mm. Underdosed areas might be present between two foci. Prolonging ex-posure time or shortening focus spacing can reduce the cool region between two foci. In addition,the influences of thermal and acoustic parameters were also studied. When the therapy depth is short(<5 cm) ,the lesion size monotonically increases with increasing attenuation coefficient that ranges from 5.4 to 11 Np/(m?MHz) . 相似文献
28.
Objective: to evaluate the efficacy and safety of ultrasound ablation of pulmonary veins for treatment of paroxysmal atrial fibrillation. Methods: The study population consisted of 9 patients with 5 males and 4 females enrolled consecutively who had idiopathic paroxysmal atrial fibrillation(AF). The ultrasound balloon was positioned through a special sheath to the orifice of the target vein by a transseptal procedure. The balloon was inflated with contrast-mixed saline (contrast: saline = 1:4) whose volume was decided by the diameter of the target pulmonary vein. The ablation energy was usually set up at 35 to 40 watts with temperature controlled at 60℃. The duration of each ablation was about 120 seconds which was repeated not over 10 times. Results: The average duration of the total procedure was 132±68 min for our patients. The average fluoroscopy time was 33±17 min. With a mean follow-up of 16±8 months after the procedure, AF was completely eliminated in 4 patients without antiarrhythmic drugs. The episodes of atrial fibrillation were eliminated in 2 patients with low dosage of oral amiodarone (0.1, once daily) which was ineffective before the procedure. The frequency of episodes was similar to that before the procedure in 3 patients. There were no complications such as hemopericardium, air embolism and stenosis of the pulmonary veins by angiography, related to the procedure. Conclusion: Ultrasound ablation of the pulmonary veins is a new approach to treat paroxysmal atrial fibrillation. Before we determined its value, we need to do more researches with bigger sample, randomization and comparison design. 相似文献
29.
以AT89S52为硬件核心,LabVIEW8.5为软件开发平台,设计了一个实时水温及水位测控系统。该系统采用单片机和DS18B20进行实时温度采集并处理分析,采用超声波对水位进行实时监控,实现对水温和水位进行实时监控。测试结果表明,该系统界面友好,测量精度高,安全可靠,易于操作。 相似文献
30.
3,5-二异丙基水杨酸制备工艺条件的优化 总被引：1，自引：0，他引：1
考察了超声波反应时间、反应温度以及催化剂浓硫酸对水杨酸烷基化反应的影响,通过正交实验设计,优化了异丙醇与水杨酸合成3,5-二异丙基水杨酸的工艺条件,在超声波反应温度60℃和浓硫酸用量13ml的条件下,常压下反应100min产率可达到31．6％,收率高于文献报道值（17．42％）。通过红外光谱熔点分析表征了产物的结构。 相似文献