低场强磁共振门静脉成像及在门静脉阻塞性疾病中的应用

目的:探讨低场强磁共振门静脉成像技术要点及在门静脉阻塞性疾病诊断中的应用.方法:收集102例患者低场磁共振门静脉成像检查资料,其中正常30例,异常72例用2D FFE序列测定造影剂循环时间,根据公式:延时时间=循环时间-1/4采集时间,计算延时时间.使用高压注射器从一侧肘静脉注入造影剂0.2mmol/kg,用3D FFE序列行冠状位扫描,对第二组门静脉期数据进行最大密度重建(MIP).结果:102例患者中,30例MRP表现正常,能清晰显示门静脉主干及肝内5级以上分支,脾静脉及肠系膜静脉亦清晰显示.72例异常,其中肝癌门静脉癌栓28例;门静脉血栓19例;门静脉狭窄21例,其中胆管癌2例,胃底巨大肿块1例,肝右叶巨大血管瘤3例,肝门区肿大淋巴结12例,胰头占位3例;肝硬化门静脉高压11例.结论:动态增强磁共振门静脉成像技术在低场磁共振机上能很好应用,成像效果与高场磁共振机无显著差异,能很好地显示门静脉结构及肝内分支,并能准确地评价门静脉阻塞性病变.     

中国传统凤纹图像与现代设计

从凤纹图像与现代设计之间的联系出发,分析和阐述传统凤纹图像对现代设计的形态与内涵上的启示意义,从而倡导人们关注中国传统艺术与文化的重要性。     

几种阳离子交换剂对纤状海泡石溶血能力的影响

本文对源于湖北广济的纤状海泡石矿通过用几种阳离子交换剂处理后，测定处理前后的纤状海泡石的溶血率，ＭＤＡ的变化以及对人体红细胞毒性的影响，发现ＮＨ＋４ ，Ｎａ＋ ，Ｋ＋ ，Ｃａ２＋ 处理纤状海泡石对人体红细胞毒性明显下降。因此认为纤状海泡石的红细胞毒性可能与脂质过氧化有关     

An Empirical Formula for Sound Absorption of Fibrous Materials

The sound absorption coefficient （SAC） curves of the nonwovens, fabrics, and thick fibrous layers with the frequency in the range of 125 - 3 200 Hz and cavity distances of 5 cm, 10 cm, 20 cm, 30 cm and 40 cm were measured. Based on analysis, it is found that the SAC is actually in direct proportion to the relative vibration amplitude of the sound wave, resulting in obtaining a mathematical expression showing that the SAC changes with the frequency for a given material. Additionally, a good corresponding relation between the maximal SAC and the permeability of the materials is discovered, thus an empirical formula is established. As a result, a complete SAC formula has been developed. In this formula, the SAC is solely a function of the sound wave frequency and permeability of the material. In comparison with sound absorption spectra of several materials, the calculated results and results measured with the formula coincide well with each other.     

硫酸软骨素／SDBS协同作用下球霰石的简易合成

通过模拟生物矿化过程，利用CO2缓慢扩散，在硫酸软骨素和十二烷基苯磺酸钠二元体系中，与富集在有机/无机界面的钙离子相结合，合成了碳酸钙晶体。系统地研究了室温下各种因素对碳酸钙晶体形貌和晶型的影响，利用粉末X-射线衍射（ XRD）、扫描电子显微镜（ SEM）等对所得的碳酸钙晶体进行了形貌与结构表征。结果显示，在不同浓度比下的硫酸软骨素和十二烷基苯磺酸钠二元体系或在不同时间下，生成的碳酸钙都具有不同的晶体结构和形貌。     

HPLC法测定乌头须根中准格尔乌头胺和宋果灵的质量比

采用高效液相色谱法测定乌头须根中准格尔乌头胺和宋果灵两种生物碱类化合物的质量比.用Zorbax Extend-C18(4.6 mm×250 mm ODS,5μm)色谱柱,以V(甲醇)∶V(w(三乙胺)=0.1%)=6∶4为流动相,流速为1.0 mL/min,检测波长220nm,柱温25℃.结果表明:在选择的色谱条件下,两种生物碱类成分可实现基线分离,且线性范围宽(0.1~10.0μg),r2=0.999 8;平均加样回收率分别为99.8%和99.3%,相对标准偏差(RSD)分别为1.49%,1.46%(n=6),质量比分别为57.0,110.0μg/g.     

一种玉米球囊增强溶栓作用的体外实验研究

通过动物血栓体外实验,对比玉米球囊及光面球囊的血栓助溶效果.取中国白兔全血标本60份制成血栓,并分为4个球囊助溶组和1个对照组.助溶组分别采用光面球囊和玉米球囊助溶.计算血栓碎块残留率并比较组间差异.结果表明:溶栓率,所有球囊助溶组均优于对照组(P0.05);玉米球囊组优于光面球囊组(P0.05).血栓裂解,球囊助溶组的血栓块直径φ≥3.7血栓块残留率低于对照组(P0.05);玉米球囊组的φ≥3.7血栓块残留率低于光面球囊组(P0.05),而φ3.7血栓块残留率则均高于光面球囊组(P0.05).由实验数据可得,球囊助溶可提高溶栓率;相同压力下玉米球囊助溶效果优于光面球囊;球囊扩张压力对溶栓率及血栓裂解程度的影响均较小.     

基于脊波变换的手背静脉图像增强及特征提取

根据人体手背静脉图像的结构及特点, 提出一种基于脊波变换的手背静脉图像增强方法, 并应用局部互联神经网络提取静脉图像特征, 加强了该生物识别系统对模糊图像的识别能力. 实验结果表明, 该方法与传统的拉普拉斯法、 平滑算法及小波变换相比有更加显著的效果.     

湖南沃溪金矿断裂构造动力成矿研究

文章重点探讨了断裂构造动力成矿的机制及模式,并以此为基础,全面分析了湖南沃溪金矿含金石英脉中金及SiO_2在断裂构造动力成矿作用下垂向和侧向上的积聚过程,指出断裂构造动力成矿作用与该矿床的形成演化有密切关系。     

Extraction and Purification of Matrix Protein from the Nacre of Pearl Oyster Pinctada fucata

A soluble matrix protein P14 with an apparent molecular mass of 14.5 kDa was isolated from fragmented nacre of pearl oysters （Pinctada fucata） treated with 10% NaOH solution to investigate the nacre matrix proteins and their effect on the CaCO3 crystal. The protein was characterized by gel exclusion chromatography and reversed-phase high performance liquid chromatography after demineralization by 10% acetic acid. The X-ray diffraction pattern of P14 crystals indicates that P14 plays an important role in nacre biomineralization. P14 can induce aragonite formation, stimulate CaCO3 crystal formation, and accelerate aragonite precipitation. Heating of the acid insoluble nacre residue, which was named conchiolin, in 10% sodium dodecyl sulfate solution supplemented with 10% β-mercaptoethanol solution for 10-20 min at about 100℃ gave two other soluble proteins having molecular masses of 19.4 kDa and 25.0 kDa. The present study suggests that these two proteins are linked to the insoluble organic matrix by disulfide bridges because the extraction yield increases when β-mercaptoethanol is added to the medium.