用功率超声消融动脉粥样硬化的研究

Ｅ９用功率超声消融动脉粥样硬化的研究姬树森，顾建军（上海交通大学上海·２０００３０）背景动脉粥样硬化（ＡＳ）是一常见病，它引发的心脑血管病是造成人类死亡的主要原因之一，它在血管内壁生成纤维性的钙化的斑块，导致血管内腔不同程度的狭窄，甚至完全堵塞，造成...     

魔镜成像(SMI)在动脉血管斑块新生血管诊断中的临床应用研究

目的:分析魔镜成像(SMI)在动脉血管斑块新生血管诊断中的临床应用价值。方法:结合超声显像血流信号Adler分级法对动脉斑块行SMI检查有血信号患者实施魔镜成像(SMI)技术检查,判断生成及斑块是否稳定。结果:魔镜成像能够清晰检测出低回声斑块、混合回声斑块的新生血管,魔镜成像诊断符合率为97.33%,差值比较无统计学意义(P0.05)。结论:魔镜成像(SMI)在动脉血管斑块能够清晰观察到斑块新生动脉血管及分级,从而判断斑块是否稳定状态。     

颈部血管超声对脑卒中功能早期改变的评估价值

目的:分析颈部血管超声结果与卒中患者功能障碍相关性,评价颈部血管超声应用价值。方法:2015年2月-2016年2月,取患者114例,在入院时、第1周-2周、90日进行颈动脉超声检测。结果:恶化者、无变化者、好转者颈动脉狭窄程度、不稳定斑块比重、斑块阳性比重差异显著,健侧MCA流速、ICAex流速与NIHSS的第2周与入院时差值具有相关性,差异有统计学意义(P0.05)。结论:颈部血管超声可作为脑卒中预后预测工具。     

血管内超声图像后处理综述

血管内超声显像是目前临床常用的诊断血管病变的介入影像手段,可在活体中观察血管壁和管腔的形态,以及斑块的形态和成分。采用数字图像处理技术,对血管内超声图像序列进行自动或半自动地处理和分析,对于血管病变的计算机辅助诊断和制定最佳诊疗方案具有重要意义。本文就近年来血管内超声图像计算机后处理的研究现状进行综述,包括图像分割和组织标定、运动伪影的抑制、血管的三维重建、血管形态和血流动力学参数的测量、组织定征显像及与其他影像的融合等,评价了目前的研究情况,并对未来的研究提出了展望。     

超微血管成像技术（SMI）在评价颈动脉粥样硬化斑块稳定性中的应用

目的:探讨超微血管成像技术(SMI)在评价颈动脉粥样硬化斑块稳定性中的应用效果。方法:选取2016.01-2019.12我院接收的68例出现颈动脉硬化斑块的患者,同时进行超声造影(CEUS)与SMI检查,对比两种检查结果进行分析。结果:本组68例136个斑块分别采用CEUS与SMI检查得出,两者在评估斑块内显示新生血管上差异无统计学意义(P0.05);两种方式在检测斑块内新生血管分级情况发现,差异无统计学意义(P0.05)。结论:SMI在评价颈动脉粥样硬化斑块稳定性中的应用效果与超声造影相当,且具有价格实惠、简单可行等优势,值得推广。     

颈动脉超声在缺血性脑血管病诊断中的价值

目的:探讨颈动脉超声在缺血性脑血管病诊断中的价值。方法:选择我院2014年3月至2015年5月收治的缺血性脑血管病患者100例,包括23例短暂性脑缺血发作(TIA)患者和77例脑梗死患者;另选择同期50例非心脑血管病患者作为对照组,全部患者均给予颈动脉超声检查,对颈动脉超声检查结果进行对比分析。结果:和对照组患者相比,缺血性脑血管病组患者的颈动脉血管壁IMT、颈动脉斑块血管检出率更高(P=0.0001,P=0.0001);TIA组患者颈动脉硬化斑块中的复合斑块、脂质斑块发生率显著低于脑梗死组(P=0.0231,P=0.0223)。结论:缺血性脑血管病的发生于颈动脉粥样硬化有直接关系,在对缺血性脑血管病进行临床诊断时,颈动脉超声检查具有非常重要的价值。     

多普勒超声对椎—基底动脉供血不足之病因的诊断价值

目的:分析多普勒超声对椎基底动脉系统缺血的诊断价值。本文主要针对颅外段椎动脉的血流变化进行探讨。方法:应用彩色多普勒超声仪器对300例出现椎-基底动脉供血不足之症状、体征的患者进行椎动脉检查,测量的参数:椎动脉内径并观察形态、显示彩色血流、收缩峰值流速、舒张末期流速峰值及阻力指数。结果:300例椎基底动脉供血不足的患者进行彩超检查中,通过血流指标分析,分别显示椎动脉扭曲、变细、闭塞,动脉硬化或斑块形成。结论:颈部彩超对于显示椎动脉壁硬化、动脉血管内附壁血栓或斑块及椎动脉内径有独特优势,还可直观准确测量血流动力学的数据,为该病的诊断与治疗提供客观依据。     

高强度聚焦超声消融滋养动脉治疗子宫肌瘤的临床价值

目的：探讨高强度聚焦超声消融滋养动脉治疗子宫肌瘤的可行性及有效性。方法：47例直径4~10cm肌壁间肌瘤,高强度聚焦超声治疗前通过彩色多普勒及超声造影确定肌瘤滋养动脉的蒂,对该区域进行消融,观察治疗前后肌瘤内部彩色多普勒及超声造影等影像学变化、随访临床症状及并发症。结果：治疗后肌瘤体积有不同程度的缩小,瘤体假包膜环状血流信号消失,肌瘤内部处于持续无灌注状态,部分患者临床症状消失或明显改善。结论：HIFU消融滋养动脉治疗子宫肌瘤能够缩短治疗时间,减少并发症,是一种微创和有效的方法。     

应用无创性影像学方法探讨冠状动脉和颅脑动脉粥样硬化相关性及临床价值

目的：探讨冠状动脉和颅脑动脉粥样硬化相关性及其临床应用价值。方法：选取疑似冠心病患者90例,分别进行CT血管造影、颈动脉超声、经颅多普勒超声检查,统计对比相关指标。结果：经CCTA评估轻度狭窄31例、中度狭窄32例、重度狭窄27例;冠状动脉狭窄程度不同患者颈动脉超声检查IMT、斑块数目差异、TCD颅内血管PI、RI指标差异具有统计学意义（P＜0.05）。结论：冠状动脉与颅脑动脉粥样硬化具有一致性,因此冠心病患者应积极诊断、治疗脑血管疾病。     

狭窄血管处管壁的变形与应力分析

该文根据血液流动连续性方程、运动方程及血管壁弹性力学方程,通过边界条件的耦合,在给定了血压波形函数的基础上,假设堵塞斑块与血管壁弹性性质相同时,求解了狭窄血管管壁的径向位移及环向应力;分析了不同狭窄程度对血管壁变形及应力的影响;给出了不同狭窄状态下,血管植入支架所需的支撑力,从而计算出植入支架后血管壁的径向位移及应力状态。该文的研究结果可为临床上对狭窄血管植入支架的变形与受力分析提供参考。     

Laboratory batch experiments of the combined effects of ultrasound and air stripping in removing CCl4 and 1,1,1-TCA from water

Ultrasonic and air-stripping techniques for removal of carbon tetrachloride (CCl₄) and 1,1,1-trichloroethane (1,1,1-TCA) from water were studied in batch experiments. Ultrasound (US) is effective for destroying organic compounds in aqueous solutions whereas air stripping (AS) efficiently transfers volatile compounds from the liquid to the gas phase. In simultaneous US and AS experiments, synergistic effects were observed and attributed to the effect of US on the mass transfer process. Using a photographic method, ultrasonic break up of gas bubbles and changes in gas holdup ratios were examined. In the two different gas-sparging systems studied, ultrasonic waves did not break up gas bubbles. In contrast, bubbles from the smaller porous size diffuser were coalesced due to sonication. In addition, both photographic and gas holdup experiments demonstrated that ultrasonic irradiation increased the gas holdup ratio. The enhancement observed in the removal of the compounds appeared to be due to this greater ultrasonic gas holdup ratio.     

Stress-wave attenuation in thin structures by ultrasonic through-transmission

The steady-state amplitude of the output of an ultrasonic through-transmission measurement is analyzed and the result is given in closed form. Provided that the product of the input and output transduction ratios, the specimen-transducer reflection coefficient, the specimen-transducer phase-shift parameter, and the material phase velocity are known, this analysis gives a means for determining the through-thickness attenuation of an individual thin sample. Multiple stress-wave reflections are taken into account, and so signal echoes do not represent a difficulty. An example is presented for a graphite fiber epoxy composite (Hercules AS/3501-6). Thus, the technique provides a direct method for continuous or intermittent monitoring of through-thickness attenuation of plate structures which may be subject to service structural degradation.     

Performance analysis for automated storage and retrieval systems

Automated storage and retrieval (AS/R) systems have had a dramatic impact on material handling and inventory control in warehouses and production systems. A unit-load AS/R system is generic and other AS/R systems represent its variations. Common techniques that are used to predict performance of a unit-load AS/RS are a static analysis or computer simulation. A static analysis requires guessing a ratio of single cycles to dual cycles, which can lead to poor prediction. Computer simulation can be time-consuming and expensive. In order to resolve these weaknesses of both techniques, we present a stochastic analysis of a unit-load AS/RS by using a single-server queueing model with unique features. To our knowledge, this is the first study of a stochastic analysis of unit-load AS/R systems by an analytical method. Experimental results show that the proposed method is robust against violation of the underlying assumptions and is effective for both short-term and long-term planning of AS/R systems.     

Selective determination of aromatic sulfonates in landfill leachates and groundwater using microbore liquid chromatography coupled with mass spectrometry

Aromatic sulfonates (AS) are large-volume chemicals used in many technical processes of, for instance, the textile industry or construction. A LC/MS method for the selective determination of AS in environmental samples, based on a single-quadrupole MS, was developed and validated. The central point of this technique is the use of the compound-specific fragment ion SO3.- as marker for aromatic sulfonates. This negatively charged SO3 radical, together with the fact that AS undergo loss of SO2, allows screening for AS in complex matrixes, even in the presence of sulfate anions. Calibration curves generated from LC/MS data showed good linearity over 3 orders of magnitude, with an absolute limit of detection of approximately 1 ng. The relative standard deviation for mean areas obtained from reconstructed ion chromatograms ranged from 2.9 to 8.6%. Unlike UV detection, this LC/MS method gives similar response for both naphthalene- and benzene-sulfonates. The method presented was successfully applied to landfill leachates and groundwater, downstream of a landfill. Furthermore, this technique allowed identification of an unknown AS found in drain samples.     

Simulation and optimization of retention in ion chromatography using virtual column 2 software

A new software package, Virtual Column 2, is described for the simulation and optimization of the separation of inorganic anions by ion chromatography (IC). The software uses a limited amount of experimental retention data acquired according to a correct experimental design to predict retention times for analytes over a designated search area of eluent compositions. The experimental retention data are used to solve a new retention model, called the linear solvent strength model, empirical approach (LSSM-EA), which then enables prediction of retention times for all eluent compositions in the search area. The theoretical development of LSSM-EA and the processes used for solving the equations are discussed. Virtual Column 2 can be used for eluents containing one or two competing ions, and the software contains retention databases for up to 33 analytes on the Dionex AS9A-HC, AS4A-SC, and AS14A analytical columns with carbonate-bicarbonate eluents and the Dionex AS10, AS15, and AS16 analytical columns with hydroxide eluents (results for the AS10 and AS15 columns are not discussed in the present study). Virtual Column 2 has been evaluated extensively and is shown to give predicted retention times that in most cases agree with experimentally determined data to within 5%. The software has uses in practical IC method development, education and training in IC, and refinement of existing IC methodology. A free version of this program is available by download at www.virtualcolumn.com.     

Regional seismic-damage prediction of buildings under mainshock–aftershock sequence

Strong aftershocks generally occur following a significant earthquake. Aftershocks further damage buildings weakened by mainshocks. Thus, the accurate and efficient prediction of aftershock-induced damage to buildings on a regional scale is crucial for decision making for post-earthquake rescue and emergency response. A framework to predict regional seismic damage of buildings under a mainshock–aftershock (MS–AS) sequence is proposed in this study based on city-scale nonlinear time-history analysis (THA). Specifically, an MS–AS sequence-generation method is proposed to generate a potential MS–AS sequence that can account for the amplification, spectrum, duration, magnitude, and site condition of a target area. Moreover, city-scale nonlinear THA is adopted to predict building seismic damage subjected to MS–AS sequences. The accuracy and reliability of city-scale nonlinear THA for an MS–AS sequence are validated by as-recorded seismic responses of buildings and simulation results in published literature. The town of Longtoushan, which was damaged during the Ludian earthquake, is used as a case study to illustrate the detailed procedure and advantages of the proposed framework. The primary conclusions are as follows. (1) Regional seismic damage of buildings under an MS–AS sequence can be predicted reasonably and accurately by city-scale nonlinear THA. (2) An MS–AS sequence can be generated reasonably by the proposed MS–AS sequence-generation method. (3) Regional seismic damage of buildings under different MS–AS scenarios can be provided efficiently by the proposed framework, which in turn can provide a useful reference for earthquake emergency response and scientific decision making for earthquake disaster relief.     

水利工程中金属焊缝缺陷的超声检测方法比较研究

为研究基于超声的无损探伤方法在水利工程金属结构焊缝缺陷识别中的应用,利用常规超声检测技术、超声相控阵技术、衍射时差法(Time of Flight Diffraction, TOFD)超声检测技术对水利工程金属结构焊接试块缺陷进行识别,分析了各种缺陷在超声无损探伤技术中的特征显示。研究结果表明:常规超声检测技术、TOFD检测技术均能对各种缺陷实现信号显示,超声相控阵检测技术对气孔和横向裂纹的显示不够明显,但对其它缺陷的检出效果较为明显;常规超声检测技术对操作人员的要求较高,对缺陷的定性困难,精度不高;TOFD检测结果中气孔和横向裂纹的显示呈现出一种特殊的弧形,有一定高度的内部裂纹和未熔合的信号由上下尖端衍射波组成,根部未焊透上下尖端信号不够明显;相控阵检测结果直观,可以较精确地测量缺陷的埋藏深度、自身高度、长度等,但在扫查点状缺陷或者与超声声束平行的裂纹缺陷时,检出率极低。     

Resistance welding of thermoplastic composites skin/stringer joints

An experimental investigation of resistance welding of APC-2/AS4 PEEK/carbon fibre composite using a stainless steel mesh heating element is presented. A special specimen geometry, the skin/stringer configuration, was used to represent a typical reinforced aerospace structural joint. The specimens consisted of a flange, representing a stringer or frame, welded onto a skin laminate. The effects of the welding parameters such as the input power level and clamping distance on the weld quality and performance were investigated. The welding parameters were optimised using short beam shear tests, ultrasonic C-scan inspection and optical microscopy. The mechanical performance of the resistance-welded skin/stringer configuration was investigated using three- and four-point bending tests and the failure mechanisms were characterised by optical and scanning electron microscopy. Two methods were used to reduce the stress concentration at the flange tip. The first method was to machine a 20° taper angle at the edge of the flange and the second one was to create a resin fillet at the flange tip. No mechanical performance improvement was obtained with the resin fillet method but the taper angle method showed 25% mechanical performance improvement when the taper angles were machined after the welding operation.     

Neural classification of Lamb wave ultrasonic weld testing signalsusing wavelet coefficients

This paper presents an ultrasonic nondestructive weld testing method based on the wavelet transform (WT) of inspection signals and their classification by a neural network (NN). The use of Lamb waves generated by an electromagnetic acoustic transducer (EMAT) as a probe allows us to test metallic welds. In this work, the case of an aluminum weld is treated. The feature extraction is made by using a method of analysis based on the WT of the ultrasonic testing signals; a classification process of the features based on a neural classifier to interpret the results in terms of weld quality concludes the process. The aim of this complete process of analysis and classification of the testing ultrasonic signals is to lead to an automated system of weld or structure testing. Results of real-world ultrasonic Lamb wave signal analysis and classifications for an aluminum weld are presented; these demonstrate the feasibility and efficiency of the proposed method     

Biomimetic coating of bisphosphonate incorporated CDHA on Ti6Al4V

Bi-functional coatings of carbonated calcium deficient hydroxyapatite (CDHA) on Ti alloys were developed by using a biomimetic coating process. The bi-functionality was achieved by loading alendonate sodium (AS), an approved bisphosphonate drug used for the treatment of osteoporosis, into the inner layers of CDHA coatings. Three possible methods of loading AS into CDHA coatings were systematically studied and compared. The results indicated that the co-precipitation method had greater benefits and can modify the release profile of AS by incorporating AS in the inner layers of the coatings. As a preliminary study, the influences of applied AS dosage to CDHA coatings were evaluated using XRD and SEM. In vitro tests indicated that the AS content on CDHA coatings played a significant role, and optimum AS content in local area is beneficial for osteoblast cells proliferation. It is expected that the CDHA–AS coatings via the co-precipitation approach have potential for bone tissue engineering applications.