水蛭分子鉴定方法的研究进展

水蛭基原复杂、市场混乱、传统方法难以有效鉴别,临床用药的安全性无法保障。分子鉴定方法根据生物间的分子特征差异进行鉴定,不受自然环境、生长发育阶段等外部因素影响,具有快速、准确、客观的特点。目前应用于水蛭的分子鉴定方法有:基于核酸的RAPD技术、SSR技术、DNA条形码技术和基于蛋白质的SDS-PAGE技术、同工酶分析技术,本文在简述水蛭不同分子鉴定方法研究进展的基础上,对水蛭不同分子鉴定方法的技术和应用特点进行比较,最后对DNA宏条形码技术、Target-sequencing技术、电化学传感检测技术在水蛭混合物,特别是中成药中水蛭成分的鉴定进行展望,旨在为水蛭鉴定方法的深入研究提供参考和借鉴。     

A Bipolar-Bisection Piecewise Encoding Scheme for Multi-Source Reverse Time Migration

Conventional shot-record reverse time migration (RTM) suffers from a high computational burden when dealing with massive data. The computational cost of RTM can be reduced by shot-encoding techniques, and plane-wave encoding is a commonly used and effective shot-encoding scheme. However, plane-wave encoding requires long time padding to avoid information loss, which decreases the efficiency of the time-domain wavefield extrapolator, and the time padding becomes longer with the increasing distance between multiple sources. The piecewise plane-wave encoding scheme cuts multiple sources into several segments prior to implementing plane-wave encoding, hence reduces the time padding, but brings new crosstalk due to the mutual interference between shots in different source segments. We suppress the crosstalk artifacts by a new bipolar-bisection amplitude encoding method, in which half of the encoding array of each migration is different from that of any other migrations to reduce the number of crosstalk terms with as few migrations as possible. We embed the bipolar-bisection method into piecewise plane-wave encoding. Compared with plane-wave encoding, the proposed scheme requires considerably shorter time padding and thus works more efficiently and can generate a qualified imaging result. The feasibility of the proposed method is tested on the 2D SEG/EAGE salt model and the Marmousi model.     

改制丁字鞋在下肢动脉DSA中的应用

目的 探讨使用改制丁字鞋制成下肢动脉造影固定鞋,防止造影检查治疗过程中肢体的移动和旋转,保持解剖学体位,提高影像质量的价值.方法 用小木钉替换丁字鞋上的铁钉,并使鞋底纵轴与支撑条呈85°;103例患者行下肢动脉造影,将无移动伪影并且体位正确者定义为A组,体位不正或有明显移动伪影者定义为B组,将B组全部患者使用固定鞋重新造影并定义为C组,并使用SPSS 18.0对三组结果进行统计学分析.结果 下肢动脉造影体位和移动伪影与年龄、疾病分类、疼痛程度,检查时间长短有关,使用固定鞋较不使用固定鞋进行造影的影像,伪影显示率下降26.09％,体位标准化率上升37.68％.结论 下肢动脉造影固定鞋结构简单,使用方便,稳定性强,能有效防止下肢移动和旋转,值得推广使用.     

Magnetic resonance imaging of the postoperative hip

Magnetic resonance imaging (MRI) is ideally suited to imaging the patient with painful hip arthroplasty due to its superior soft tissue contrast, multiplanar capabilities, and lack of ionizing radiation. MRI is the most accurate imaging modality in the assessment of periprosthetic osteolysis and wear-induced synovitis, and can also assess regional tendons and neurovascular structures. This article discusses the technical aspects of MRI around metallic implants as well as the appearance of potential complications following hip arthroplasty, including osteolysis, wear-induced synovitis, infection, hemarthrosis, fracture, loosening, component displacement, heterotopic ossification, tendinopathy, and neurovascular impingement. The specific complication of metal hypersensitivity following metal-on-metal prostheses is reviewed.     

Artifact removal in the context of group ICA: A comparison of single‐subject and group approaches

Independent component analysis (ICA) has been widely applied to identify intrinsic brain networks from fMRI data. Group ICA computes group‐level components from all data and subsequently estimates individual‐level components to recapture intersubject variability. However, the best approach to handle artifacts, which may vary widely among subjects, is not yet clear. In this work, we study and compare two ICA approaches for artifacts removal. One approach, recommended in recent work by the Human Connectome Project, first performs ICA on individual subject data to remove artifacts, and then applies a group ICA on the cleaned data from all subjects. We refer to this approach as Individual ICA based artifacts Removal Plus Group ICA (IRPG). A second proposed approach, called Group Information Guided ICA (GIG‐ICA), performs ICA on group data, then removes the group‐level artifact components, and finally performs subject‐specific ICAs using the group‐level non‐artifact components as spatial references. We used simulations to evaluate the two approaches with respect to the effects of data quality, data quantity, variable number of sources among subjects, and spatially unique artifacts. Resting‐state test–retest datasets were also employed to investigate the reliability of functional networks. Results from simulations demonstrate GIG‐ICA has greater performance compared with IRPG, even in the case when single‐subject artifacts removal is perfect and when individual subjects have spatially unique artifacts. Experiments using test–retest data suggest that GIG‐ICA provides more reliable functional networks. Based on high estimation accuracy, ease of implementation, and high reliability of functional networks, we find GIG‐ICA to be a promising approach. Hum Brain Mapp 37:1005–1025, 2016. © 2015 Wiley Periodicals, Inc .     

Economical Sponge Phantom for Teaching,Understanding, and Researching A‐ and B‐Line Reverberation Artifacts in Lung Ultrasound

This project evaluated a low‐cost sponge phantom setup for its capability to teach and study A‐ and B‐line reverberation artifacts known from lung ultrasound and to numerically simulate sound wave interaction with the phantom using a finite‐difference time‐domain (FDTD) model. Both A‐ and B‐line artifacts were reproducible on B‐mode ultrasound imaging as well as in the FDTD‐based simulation. The phantom was found to be an easy‐to‐set up and economical tool for understanding, teaching, and researching A‐ and B‐line artifacts occurring in lung ultrasound. The FDTD method–based simulation was able to reproduce the artifacts and provides intuitive insight into the underlying physics.