血液动力学中血管流激波与驻波的相互作用

血液动力学问题是生物力学心血管系统中的重要研究课题.血管内斑块处,血管截面和血管壁的材质发生变化,对血液流动产生重要影响.血液流动中基本波及其相互作用对探究血液流动的规律、生理学意义及与疾病的关系有着重要的意义.本文研究血液动力学血液流动简化数学模型的基本波的相互作用.血管流模型是3×3非严格双曲型方程组.构造性地得到了初值为三段常状态时,血管流问题的解,即解决了激波与驻波的相互作用问题.特别地,给出四种后前激波与驻波的相互作用的结果.     

基于拉曼光谱方法研究不同剪切力下的红细胞亚损伤

利用共聚焦拉曼光谱技术,对人工心脏泵不同剪切应力下受到亚损伤的红细胞进行实验研究,验证拉曼光谱对红细胞亚损伤程度的评估能力,为血液损伤评价提供了一种新的思路。实验采集血红蛋白和红细胞的拉曼光谱标准谱图并进行对比分析,以确定红细胞谱图特征峰的归属。用血液剪切力试验平台对测试血样施加暴露时间为1 s,大小分别为0,50,100,150,200,250和300 pa的剪切力。利用共聚焦拉曼仪器,在10倍长焦物镜,532 nm激光光源波长,积分时间10 s,积分次数2次,2.5 mW功率下采集剪切应力作用后的红细胞拉曼谱图。通过归一化的方法对比红细胞的拉曼谱图变化,评估红细胞亚损伤的程度,运用曲线拟合方法对特征峰和剪切应力进行拟合,验证拉曼光谱对红细胞亚损伤的评估能力。对比血红蛋白和红细胞的拉曼光谱标准谱图发现,红细胞谱图能够反映血红蛋白的内部结构。且结果表明,拉曼光谱法可以用于区分不同剪切应力下亚损伤的红细胞,推断剪切应力可以透过细胞膜从而影响到其内部的血红蛋白结构。且随着剪切力的增大,1 376 cm-1位置左侧谱线呈现明显抬高趋势,1 549和1 604 cm-1位置的峰强增高,1 639 cm-1位置的氧浓度标记带ν₁₀振动谱带减弱。其中1 549 cm-1位置的峰强为亚铁离子高自旋带,在不同剪切力的作用下,峰强差异表现最明显,与剪切应力呈明显的正向线性关系,拟合效果良好。拉曼光谱法检测样本处理简单、耗时短、操作简便、重现性好,且可以精确的检测到细胞内部结构的细微变化,可以评估红细胞的亚损伤程度,弥补了传统评价溶血的方法的不足,为人工心脏泵血液损伤评价提供了新的技术手段,拓宽了拉曼检测方法的应用领域。     

UPLC-ESI-QTOF/MS and multivariate data analysis for blood plasma and serum metabolomics: Effect of experimental artefacts and anticoagulant

Clotting and anticoagulation of blood samples may give rise to different metabolic profiles of serum and plasma samples, respectively. The anticoagulant used for blood plasma preparation may affect the resulting metabolic profile due to different mechanisms involved in anticoagulation by various agents, e.g. heparin, EDTA and citrate. In the present study, we looked into metabolite and other differences in matched serum and plasma samples and different plasma preparations by using untargeted UPLC-ESI-QTOF/MS profiling and multivariate data analysis (PCA and OPLS-DA). Metabolite differences between serum and plasma samples were mainly related to small peptides reflecting presence or absence of coagulation. Only subtle metabolite differences between the different plasma preparations were noticed, which were primarily related to ion suppression or enhancement caused by citrate and EDTA anticoagulants. For the first time, we also report that anticoagulant counter cation (Na+ or K+) in Na-citrate and K-EDTA plasma can make some metabolites more dominant in ESI-MS. Polymeric material residues originating from blood collection tubes for serum preparation were observed only in serum samples. Hypoxanthine and xanthine were found at higher levels in serum than in plasma samples, possibly due to release from the clot. Mass spectral features of sodium formate and potassium formate ion clusters were detected in citrate and EDTA plasma samples, respectively, originating from formate in mobile phase and Na⁺ (in Na-citrate tubes) and K⁺ (in K-EDTA tubes). Among the anticoagulants, heparin is recommended for plasma samples used for LC-ESI/MS-based metabolomics of hydrophilic compounds because no plasma interferences or matrix effects were noticed for this polarity range. Citrate and EDTA should be avoided since interferences and serious matrix effects were encountered on some co-eluting polar metabolites. Serum is recommended as a second choice and an alternative to plasma. In conclusion, heparin plasma or serum should be the order of best choice for LC-ESI/MS-based metabolomics research.     

A Practical Manufacturing Synthesis of 1-(R)-Hydroxymethyl-Dtpa: An Important Intermediate in the Synthesis of MRI Contrast Agents

An efficient synthesis of alcohol 2 is described from L-Serine (OMe) in four synthetic steps. The process uses readily available reagents and is suitable for manufacturing.     

A Concise Route to 3-Hydroxy-4-Methoxy-5-Methylbenzaldehyde Derivative

3-Hydroxy-4-methoxy-5-methylbenzaldehyde derivative (1c) has been synthesized in 7 steps from 2,3-dihydroxytoluene (4). An isopropyl derivative has been used to protect a phenol during this transformation. The overall yield of 1c was 37%.     

ICP-AES法同时测定人发、血液、唾液、牙石中的多种元素

本文应用ICP-AES法同时测定人发、血液、唾液及牙石中多种微量元素,采用HNO_3-HClO_4体系溶解样品。具有取样量少,样品处理简单、快速,测定准确等优点。本法回收率在91～106%之间,可为现代医学提供可靠的科学依据。     

Non-invasive glucose sensing with near-infrared spectroscopy enhanced by optical measurement conditions reproduction technique

Non-invasive glucose sensing utilizing near-infrared spectroscopy (NIRS) has been a focusing topic in biomedical optics applications. However, different probing locations and contact pressures between the probe and skin cause variations in the light propagation paths within tissue, making it very hard to obtain stable near-infrared spectra concerning body content. This paper proposes one possible solution to the reproduction of light propagation within tissue for near-infrared non-invasive glucose sensing systems by introducing the optical measurement conditions reproduction technique. Results of experiments on glucose concentrations within human body through application of our proposed system show a RMSEP value of 15–20 mg/dL and a correlation coefficient greater than 0.8.     

Chemistry and function of human plasma proteins

Human blood plasma contains a large number of proteins. New analytical and preparative techniques have so far permitted the isolation of more than one hundred such proteins; about ninety percent of these were first characterized in the last 30 years. The plasma proteins include components of the clotting and complement systems as well as proteinase inhibitors, immunoglobulins, lipoproteins, and carrier proteins. The biological function of some of the plasma proteins is not yet known. Deficiency of one or more plasma proteins usually causes serious health disorders, the best known example being hemophilia. Several biologically active proteins can be gained from blood plasma; these proteins—for example the blood clotting factors—are of great prophylactic and therapeutic importance and allow a better exploitation of the valuable plasma than can be obtained by means of transfusion.