不同形状界面对界面射流的影响──彩色多普勒与激光荧光染料方法的研究

本文通过应用彩色多普勒及激光荧光染料显示射流方法研究了不同形状界面对射流的影响。结果表明对照组及平坦界面射流时，彩色多普勒与激光荧光染料两种方法无显著差异；在弯曲界面条件下，彩色多普勒射流小于激光荧光染料射流（Ｐ＜０．０１～０．０００１）。彩色多普勒研究表明不同形状界面射流大小分别与每搏容量相关好（ｒ＝０．８３～０．９９），但射流大小明显不同。凹形界面射流面积最小，平坦及凸形界面射流面积也小于对照组。研究提示不同形状界面可以导致界面射流不同程度地减小，并且彩色多普勒也不易对弯曲界面的射流完全成像。在临床上应用彩色多普勒对返流定量时，需考虑上述影响。     

Complete structure of eclosion hormone of Manduca sexta

The locations of the three disulfide bonds of eclosion hormone (EH) isolated from Manduca sexta were assigned by sequence analysis of thermolysin fragments and by comparison of a key heterodimeric fragment to regiospecifically synthesized parallel and antiparallel isomers. We elucidated the complete structure of Manduca EH as a 62-residue peptide which has three disulfide bonds between Cys¹⁴-Cys³⁸, Cys¹⁸-Cys³⁴, and Cys²¹-Cys⁴⁹.     

茶叶多糖的研究进展

茶叶多糖是一种复合杂多糖，具有许多生物活性。作者系统地介绍了茶叶多糖的提取、分离、纯化、纯度鉴定及相对分子质量测定的方法，以及其含量和组成、理化性质、化学结构及空间构象、生物活性等方面的研究进展，并对上述方法及研究进展进行了分析和评述。     

Transceive surface coil array for MRI of the human prostate at 4T.

A novel torso transceive surface coil array for prostate magnetic resonance imaging (MRI) and spectroscopy (MRS) at 4T is presented. It is shown that with the use of a conformal transceive surface coil array with 50 Omega transmitter amplifiers and receiver preamplifiers, one can perform whole-volume torso imaging while maintaining the high signal-to-noise ratio (SNR) inherent to surface coil designs. Recent theoretical considerations have shown that by focusing the infringing radiofrequency (RF) electromagnetic field, one can achieve increased penetration and signal homogeneity compared to a conventional circularly polarized driving scheme. A variation of this driving scheme particular to the proposed coil design resulted in a twofold increase in SNR in the prostate compared to that achieved with a conventional circularly polarized driving scheme. The novel transceive surface coil array presented is capable of full-volume imaging of the human torso at 4T while maintaining signal penetration in the deep region of the prostate gland.     

Transplant data: sources, collection and research considerations, 2004

The process of collecting and analyzing transplant data is complex. Familiarity with how these data are collected is crucial to a thorough understanding of the information. This article focuses on available OPTN-SRTR data and the continuing evolution of data collection mechanisms; how that data collection system is improving the data quality and reducing the data collection burden; how additional ascertainment of outcomes both completes and validates existing data; and caveats that remain for researchers. This year's article focuses further on research considerations related to cohort choice, timing of data submission, and potential biases in follow-up data. Ongoing improvements in data collection timeliness and scope are covered. The impact of extra ascertainment of outcomes, particularly for post-transplant kidney graft failure from Medicare data, are also examined. A section on graft failure reporting among different sources traces the steps by which the SRTR reconciles different data sources in its analyses. It is important that those reading and conducting transplant research understand the origin, structure, and scope of the available data. All of these issues should be carefully considered when choosing cohorts and data sources for analysis.     

Structure function interface with sequential shortening of basal and apical components of the myocardial band

Objective: To mechanically test the intact cardiac structure to determine the sequence of contraction within the myocardial mass to try to explain ejection and suction. Methods: In 24 pigs (30–85 kg), segment shortening at the site of sonomicrometer crystals was continuously recorded. The ECG evaluated rhythm, and Millar pressure transducers measured intraventricular pressure and dP/dt. Results: Study of segment shortening defined a sequence of contraction within the myocardial mass, starting at the free wall of the right ventricle and on the endocardial side of the antero-septal wall of the left. Crystal location defined underlying contractile trajectory; transverse in right ventricle followed by basal posterior left ventricle, and from the endocardial anterior wall to the posterior apical segment and finally to the epicardial side of the anterior wall. Mean shortening fraction averaged 18±3%, with endocardial exceeding epicardial shortening by 5±1%. Epicardial segment crystal displacement followed endocardial shortening by 82±23 ms in the anterior wall, and finished 92±33 ms after endocardial shortening stopped, time frame that matches the interval of fast drop of ventricular pressure and the start of suction. Conclusions: Crystal shortening fraction sequence followed the rope-like myocardial band model to contradict traditional thinking, with two starting points of excitation–contraction, the right anterior free wall of the right ventricle, and the endocardial side of the anterior wall. Active suction may be due to active shortening of the epicardial fibers of the anterior wall, because relaxation was not detected when both mitral and aortic valves were closed during the interval previously termed ‘isovolumetric relaxation’.     

老年冠心病患者踝臂指数和心脏结构与功能的相关分析

目的探讨老年冠心病患者踝臂指数(ABI)和心脏结构与功能的相关性。方法87例老年冠心病患者,按ABI分组,A组ABI≤0.9,B组ABI>0.9,同时测量2组的心脏结构指标:左心房直径(LAD)、左心室舒张期直径(LVDD)、左心室后壁厚度(LVPW)。左室收缩功能指标:左室缩短率(FS)、左室射血分数(EF)。左室舒张功能指标:EF斜率。结果A、B2组比较,年龄、血脂、血糖、肝功能、肾功能、LAD、LVDD、LVPW和EF斜率均无显著性差异。FS和EF均有显著性差异,A组较B组明显降低(P<0.05)。结论ABI与老年冠心病患者的心脏功能有较好的相关性,对其预后的判定有一定的价值。     

氨乙基氨丙基聚二甲基硅氧烷改性水性聚酯型聚氨酯的研究

由聚酯二元醇、异佛尔酮二异氰酸酯和二羟甲基丙酸合成聚氨酯预聚体，以氨乙基氨丙基聚二甲基硅氧(AEAPS)为扩链剂，制备了AEAPS改性聚氨酯水分散液。与未改性的聚氨酯水分散液相比，AEAPS改性聚氨酯水分散液的粒径增大，但粒径分布和表面张力基本不变，说明疏水的聚二甲基硅氧烷侧链被包裹于分散颗粒的内部；此外，改性聚氨酯水分散液的冻融稳定性显著增强。AEAPS改性聚氨酯水分散液成膜后，吸水率明显下降，水在膜表面的接触角增加，400℃时热失重下降，具有良好的疏水性和耐热性。     

阴茎包埋对海绵体内一氧化氮合酶的影响

目的:探讨阴茎包埋对海绵体内一氧化氮合酶(NOS)活性的影响。方法:通过建立大鼠隐匿阴茎模型获得实验标本,分2个月组、4个月组和6个月组进行观测,每组80只大鼠。各阶段中包括包埋组(n=50)、假手术组(n=15)和正常组(n=15)。称量大鼠体重和海绵体重量后,采用化学比色法检测海绵体内NOS活性。结果:各阶段包埋组阴茎海绵体重量、体重及两者的比值与正常组和假手术组比较均无显著性差异(P>0.05);包埋降低大鼠阴茎海绵体组织的NOS活性(2个月组P>0.05,4个月组P<0.05,6个月组P<0.01)。结论:阴茎包埋可影响海绵体内NOS活性,且与包埋时间呈正相关,但对海绵体外观和重量无明显影响。