A study of streaming in plant tissue induced by a Doppler fetal heart detector

A study has been made of acoustic microstreaming in leaves of Elodea and in sections of the primary root tip of Vicia faba placed in a standing wave field produced by a Doppler fetal heart detector. The transducer frequency was 2.1 MHz and the total power output 7.0 mW which gave an effective intensity of 43 mW/cm² at the centre of the ultrasound beam. The microstreaming was observed by light microscopy and took the form of the rotation of chloroplasts and other organelles. It was only found in association with channels of intercellular gas, and is thought to result from the acoustically stimulated pulsation of these channels. Quantitative observations of rotation speeds, threshold intensities and the variation in acoustic activity with time were made.     

Transmission of ultrasound beams through human tissue--focusing and attenuation studies

The focussing of ultrasound through human tissue has been measured for a range of transducer diameters (11–50 mm). The defocussing effects appear to be due to two major mechanisms: (1) attenuation and (2) phase distortion of the converging wavefront due to refractive index variations in the tissue. Attenuation studies show that the first mechanism is responsible for a large proportion of defocussing and can be controlled by the frequency bandwidth of the system. The second mechanism is important for heterogeneous tissues such as breast, where large fractions of the ultrasound energy can be deflected off axis. Focussing properties were highly dependent on tissue type, however for all tissues, optimum focussing was achieved below a focal-number of 3.     

An automatic method of measuring inhibition of root growth of seedlings of Vicia faba following ultrasonic irradiation

A new method of monitoring the root growth of Vicia faba is described. This system comprises a double conductivity cell, each compartment accommodating one group of beans. The device is placed in a water-filled culture tank. The cell is connected to a high frequency bridge circuit, the out-of-phase signal from the bridge being extracted by a phase-sensitive detector, smoothed and amplified, and then passed to a pen recorder. The method can be used to continuously monitor either the growth of one set of beans in one compartment or the difference in growth rate between groups of beans. Traces are shown which illustrate the value of this approach.     

Characterization of medical ultrasonic transceivers. Gain transfer characteristics and their applications.

The concept of gain transfer characteristics of medical ultrasonic transceivers is presented. Transfer characteristics relate the peak echo amplitude at the output of the receiver to the attenuation of a reproducible reference echo, at discrete time gain compensation (TGC) voltage levels. A method is shown for the determination of the transfer characteristics, and their numerous applications are described.     

Influence of hypertension and smoking as the single vascular risk factors on the intima-media thickness

In order to compare the extent of early carotid atherosclerosis between patients with single vascular risk factors (smoking = SMO or hypertension = HYP) and risk-free normal subjects ( = HCS), we used intimal-medial wall thickness (IMT) measurements of the common carotid artery. The age- and sex-adjusted mean IMTs were significantly higher in the HYP and SMO groups than in the HCS control group (p < 0.005 and p < 0.001, respectively). The estimated yearly progression rate of IMT (average difference in IMT/year age difference) was significantly higher in the HYP and SMO groups than in the HCS group (p < 0.05). In the total group, the age, hypertension, smoking and sex accounted for 52% of the variability of IMT. Our results show that the estimated yearly progression rate of IMT is slower in healthy and risk-free volunteers than previously detected and that the smoking and hypertension have a similar effect to the progression of early atherosclerosis. This also emphasises the influence of smoking in initial vascular remodelling process.     

诊断超声辐照后大鼠睾丸生精细胞P53 mRNA、Bcl-2 mRNA表达改变

目的　检测诊断超声与细胞凋亡相关基因P53和Bcl-2mRNA的关系。方法　32只SD雄性大鼠随机分为4组对照组、10min组、20min组和30min组,应用HP8500彩色血流显像仪,探头频率7.5MHz,超声输出功率6.8mW,空间平均时间平均声强3.4mW/cm     

超声造影评价肝癌微波治疗疗效的初步应用

目的　探索超声造影能量多普勒血流检查评价微波治疗疗效的价值。方法　超声造影剂Levovist检查17例肝癌经皮微波凝固治疗病人。治疗前1d内及治疗后3d、7d对比检查能量多普勒血流图(PDI)、超声造影能量多普勒血流图(CEPDI)及瘤区再活检,并于治疗后1个月、3个月及6个月超声及增强CT随访。结果　(1)造影后CEPDI肿瘤区血流信号显示率明显增加(P＜0.05),并能显示瘤内细小血管的分布状况及其与周边血管尤其是肿瘤滋养血管及其分支进入肿瘤的详细部位;治疗后CEPDI瘤内及周边肿瘤滋养血管消失;(2)肝癌造影瘤内能量多普勒血流信号增强峰值时间平均43.3s,持续时间179.9s;(3)治疗后CEPDI瘤内血流阴性者再活检肿瘤坏死完全。结论　超声造影能量多普勒血流成像能清楚显示肝肿瘤滋养血管及其分支以及肿瘤内的分布状况,并能于治疗后短期内及时判断肿瘤坏死情况,可望成为临床超声检查观测肝癌局部治疗疗效并指导治疗的有效可靠方法。     

超声波治疗疼痛触发点的研究现状

大多数颈肩腰腿痛都与肌筋膜疼痛触发点的产生及活化有关，而对于其治疗手段也是多种多样。相对于传统的注射技术和针法，超声波治疗技术因其无创、经济、安全及有效被广泛用于疼痛触发点的临床治疗。本文通过阅读大量的文献，对超声波治疗疼痛触发点的研究现状进行综述。     

超声体表定位经皮肾穿刺活检术后并发症

肾脏疾病分类复杂,临床诊断较困难,肾脏活组织检查（简称肾活检）已成为明确诊断、判断预后以及制定治疗方案的重要依据。本文回顾性分析于我院接受超声体表定位经皮肾穿刺活检后出现并发症的病例,旨在提高其安全性。     

单纯性肾囊肿112例临床分析

本文分析了川东地区干部保健体检,经B超和CT检查720例患者肾和肝等器官,发现单纯性肾囊肿112例,检出率15.55％。按年龄分三组,44岁以下组囊肿检出率8.04％(28/348),45～69岁组检出率16.31％(44/269),60岁以上组检出率38.83％(40/103),组间比较差异非常显著(P<0.005),说明囊肿的发生随年龄的增长而递增。单发性肾囊肿89例(72.32％)多于多发性囊肿23例(27.68％)。囊肿的大小与年龄无关。绝大多数患者无临床表现。全部患者肾功能均正常。伴发肝囊肿13例(11.6％)。