Tb(III) Speciation in Human Blood Plasma by Computer Simulation

With the wide application of rare earth fertilizer and medicines1, more and more rare earths enter into environment, and also into human body via food chain. Now it is very urgent to study the biological effect of rare earths on human health and environment. After entering into human body by whatever route, lanthanide ions are transported to secondary deposition sites mainly via the plasma in the blood stream. So it is very important to study lanthanides speciation in human blood plasma. Becau…     

Human Serum Albumin Hybrid Incorporating Synthetic Hemes:A Novel O_2-Carrying Hemoprotein

It has long been known that homologous blood transfusion will result in a lot ofserious problems such as viral infections,for example AIDS,hepatitis,antigenicsensitization and GVHD;therefore aggressive testing of donor blood has beenadopted[1 ,2 ] .Even after this introduction,which is time-consuming and expensive,wecould not eliminate all the risks. In the wake of these kinds of pitfalls,production andclinical use of the blood substitutes have emerged.The essential aim of blood substitutei…     

龋病人牙釉质表面硬度及抗磨损性能测试

采用人工方法制成人牙釉质浅龋及使用抗龋措施的龋损釉质样本,分别测量各组釉质表面显微硬度,并以微动摩擦磨损试验机测试其抗磨性能,试验结果表明：各组实验组釉质较对照组表面硬度都有不同程度下降,氟化钠前处理会使釉质表达硬度显著下降,人工浅龋牙釉质的抗磨损性能不如正常釉质,使用两种抗龋措施对其抗磨性能没有明显改善。     

心电激励下的人体左心室力学响应分析

人体心脏通过电兴奋引起的心肌收缩实现泵血功能 ,而心肌的力学特性高度依赖于肌纤维结构。本文根据肌纤维旋向和复合材料理论以及电生理心脏模型建立了左心室的有限元机械模型 ,仿真研究了左心室在心电兴奋力作用下的力学响应。结果表明左心室的收缩过程是十分复杂的 ,包括轴向和径向的收缩及绕长轴的不同程度的旋转扭曲。从总体趋势上看 ,心尖处变形最为严重。此外 ,仿真结果还表明 ,心壁应力分布不均匀 ,从内壁到外壁有所减少 ;在心尖和心底部应力较大 ,其中内壁心尖处应力最大。这些结果说明了心脏的力学特性与心肌纤维结构、左心室的几何形状以及电兴奋刺激密切相关。作者将本文的仿真结果与医学图像及其它模型进行了对比分析 ,结果表明了该模型用于分析心肌力学功能特性的可行性     

Effect of shear on human insulin in zinc suspension

Human insulin in zinc suspension was used as a model protein to test the effect of shear on the settling rate of proteins, a possible inference for protein denaturation. The rate of settling was determined directly in a spectropho-tometer. Shear effects are important in retaining the activity of proteins and are present in bubble, foam, and droplet protein fractionation processes. A sim pletest, such as that conducted here, mayeven be useful for monitoring changes in protein structure caused by commercial shipping of the protein. The settling ratefor insulin was continously monitored in theoriginal bottle by spectrophotometric absorbance changes as a function of time. A settling curve was determined following each shear experiment, which included shaking the “worked” insulin solution in a vortex mixer for different lengths of time. It was determined, when comparing long shaking times with short ones, that the initial settling rate was less for the long-term shaking of the insulin samples and greater for the short-term shaking. The secondary effects of light and heat, along with shaking, a pparently did not produce differences from shaking alone.     

气相色谱-质谱联用法检测母乳脂肪中反式脂肪酸

建立了母乳中反式脂肪酸(TFAs)的气相色谱-质谱(GC-MS)检测方法,并应用于母乳脂肪中TFAs的检测。母乳用氨水水解,乙醚和石油醚提取脂肪,提取的脂肪加入C21: 0内标,用三氟化硼甲醇溶液在80℃水浴中冷凝回流15 min进行甲酯化,正己烷提取,上清液用GC-MS分析,内标法定量。在低、中、高加标水平上验证方法的准确度与精密度,结果显示该方法可用于母乳中18种TFAs及其同分异构体的检测,其中12种TFAs在母乳脂肪中的方法检出限为4.0~47.1 mg/kg,回收率为80%~113%, RSD为2.9%~14.5%(n=6)。TFAs在部分母乳脂样品中检出,含量为9.54~6.9 mg/kg。该方法定性、定量准确,可有效用于母乳中TFAs的检测,但仍存在脂肪酸本底干扰等问题,可结合银离子固相萃取柱预分离技术进一步完善。     

A novel liquid chromatographic method with fluorescence detection for quantitation of tadalafil and dapoxetine hydrochloride in pharmaceutical dosage form and human plasma北大核心CSCD

Tadalafil( TAD)and dapoxetine HCl( DAP)are recently co-formulated and both show native fluo-rescence. Therefore,a novel,accurate,specific and sensitive reversed-phase high performance liquid chroma-tographic method with fluorescence detection was developed and validated for their separation and quantitation in dosage form and human plasma using avanafil as an internal standard( IS). Separation was achieved using isocratic elution within 7. 0 min on C18 column and acetonitrile-0. 15% triethylamine( 40∶60,v/v;pH 4)as a mobile phase. The flow rate was 1. 0 mL/min and the detection was time-programmed at 330,410 and 370 nm for TAD,DAP and IS,respectively,after excitation at 236 nm. The linear ranges from 0. 01 to 30. 00 μg/mL for each drug with the limits of detection of 4. 20 and 7. 20 ng/mL for TAD and DAP,respectively. The method was validated in accordance to the International Conference on Harmonization( ICH)guidelines and was successful-ly applied to spiked human plasma with mean recoveries of 98. 17% and 98. 83% for TAD and DAP respectively.     

氯化血红素的催化显色反应及分析应用

本文研究了以氯化血红素替代辣根过氧化物酶催化过氧化氢与4-氨基安替比林和苯酚的催化显色反应条件,拟订了测定过氧化氢的高灵敏催化分光光度法,做了多种离子对测定过氧化氢的干扰实验。并通过与葡萄糖氧化酶联用,拟订了水介质和血清中葡萄糖的分光光度测定方法,试用于测定血清样品中的葡萄糖含量得到了较满意的结果。     

Renaturation with simultaneous purification of rhG-CSF from Escherichia coli by ion exchange chromatography

Protein refolding is a key step for the production of recombinant proteins, especially at large scales, and usually their yields are very low. Application of liquid chromatography to protein refolding is an exciting step forward for this field. In this work, recombinant human granulocyte colony-stimulating factor (rhG-CSF) expressed in Escherichia coli was renatured with simultaneous purification by ion exchange chromatography (IEC) with a Q Sepharose FF column. Several chromatographic parameters affecting the refolding yield of the denatured/reduced rhG-CSF, such as the urea concentration, pH value, concentration and ratio of reduced/oxidized glutathione in the mobile phase, as well as the flow rate of the mobile phase, were investigated in detail and indicated that the urea concentration and the pH value were of great importance. At the optimal conditions, the renatured and purified rhG-CSF was found to have a specific bioactivity of 3.0 x 10(8) IU/mg, a purity of 96%, and a mass recovery of 49%. Compared with the usual dilution method, the IEC method developed here is more effective for rhG-CSF refolding in terms of specific bioactivity and mass recovery.