Liquid Chromatographic Assay of Peptides Activity with Inhibiting Angiotensin Converting Enzyme

A rapid, simple and interference-free method was developed to evaluate the inhibitory activity of hydro-lyzed peptides from egg white protein against the angiotensin-converting enzyme. The total reaction volume was 60 μL, saving the cost. The assay was based on a HPLC separation and quantification of the synthetic substrate hip-puryl-L-histidyl-L-leucine and its hydrolyzed product―hippuric acid; the separation was performed on a C 18 column eluted by a mobile phase of acetonitrile/water(0.5% TFA) at a volume ratio of 25:75. At a signal to noise ratio(S/N) of 10, the detective limit of the quantitation of hippuric acid was (0.4600±0.0097) μmol/L. The standard curve shows a linear response with a slope of 49488 and a correlation coefficient of 0.9995. The assay was adequate for the study of ACE inhibition by Captopril and peptides derived from food protein, and showed a very good correlation with the previous methods.     

染料敏化光催化还原水制氢

光敏化效应最早可追溯到大约170年前.早在1839年,Becquerel等人将氧化铜或卤化银涂在金属电极上,他们发现该电极在可见光照射下能够产生光电压[1].1887年,Vienna大学的Moser教授等人在卤化银电极上涂上染料赤藓红(erythrosine)的实验结果进一步证实了染料的光敏化效应[2].然而,直到德国科学家Tributsch等人在20世纪60年代阐释了染料吸附在半导体上并在一定条件下产生电流的机理,这一现象才引起广泛关注[3,4].     

曙红Y与牛血清蛋白作用的荧光光谱研究及分析应用

在pH 2.53的介质中,曙红Y与牛血清蛋白（BSA）作用形成复合物,最大吸收峰从513nm红移到529nm,曙红Y荧光光谱发生显著变化,最大发射光波长540nm（最大激发光波长308nm）荧光猝灭,其猝灭程度与BSA含量成正比,线性范围0－2.5mg/L ,相关系数0.999,检出限2.8μg/L(3σ）。作者研究了反应条件、干扰物质及进行了样品测试,结果令人满意。     

新的氨基酸受体的合成和分子识别性质研究

从双氨基甲基手性双环胍出发,经三步反应合成了由稳定的共价键桥联双环胍、氮杂冠醚和萘环的氨基酸受体1.液-液竞争萃取和^1HNMR实验表明受体对氨基酸两性离子具有较好的侧链选择性和对映选择性,能够选择性地将L-芳香族氨基酸从水相转移到二氯甲烷有机相。     

15(R,S)-dl-ω-乙基-13,14-去氢前列腺素F2α的合成

本文报道从双羟环氧(4)与3-叔丁氧基癸炔-1的铝试剂(3)在甲苯中开环,再经铂催化氧化、二异丁基铝氢还原、Wittig反应及三氟乙酸水解等反应合成15(R,S)-dl-ω-乙基-13,14去氢前列腺素F_2α,并用活性二氧化锰氧化代替金属铂的催化氧化,获得满意结果。15(R,S)-dl-ω-乙基-13,14-去氢前列腺素F_2α经药理试验表明,有强的溶解黄体及抗生育作用,对平滑肌的收缩作用则较低。对于治疗奶牛持久黄体及诱发母牛同期发情有效。     

PEO/PVAc共混体系辐射交联反应中溶胶分数与辐照剂量间的关系

In this paper, the relationship between T_m and composition of PEO/PVAc blend were studied and the Flory-Huggins parameter of the blend system were calculated. The experimental results show that this blend system is compatible and have only one glass transition temperature (T_g), so we can extend the relationship between sol fraction (S) and radiation dose (R) of linear polymer to the PEO/PVAc system. The Bb value of PEO/PVAc system were calculated, which is in good agreement with the experimental value.     

A Study of the Probe Effect on the Apparent Image of Biological Atomic Force Microscopy

The atomic force microscopy (AFM) possesses high spatial resolution and it is compatible with liquid environments. AFM can provide possibility to study a wide range of biological problems at the molecular level and acquire topological information at nanometre resolution under physiological conditions1,2. However, a major problem for image reconstruction of biological specimens is that structures of most biological molecules are very soft and delicate, which could be easily deformed and dama…     

Graphene–Au composite sensor for electrochemical detection of para-nitrophenol

A novel electrochemical sensor for para-nitrophenol (p-NP) was constructed with graphene–Au composite containing 10 % Au (G–Au 10 %). In the composite, Au nanoparticles with the size of ca. 11 nm were regularly scattered on graphene sheet without aggregation, which offers dramatically higher electrocatalytic activity on the redox of K₃[Fe(CN)₆]/K₄[Fe(CN)₆] couple than sole Au nanoparticles. Compared to sole Au nanoparticles, the G–Au 10 % also exhibited dramatically improved electrocatalytic activity on the reduction of p-NP. Amperometric detection of p-NP at G–Au 10 % modified electrode displayed a wide linear range of 0.47–10.75 mM with detection limit of 0.47 μM and a high sensitivity of 52.85 μA/mM. Considering the thrifty in utilization of noble Au, the G–Au 10 % can be successfully applied as a low-cost and powerful sensing material for trace detection of p-NP.     

Plasmonic biosensing based on non-noble-metal materials

This review focuses on the research progress of non-noble-metal materials with nanostructures for plasmonic biosensing. Firstly, the physical and sensing principles of localized surface plasmon resonance (LSPR) sensors are briefly introduced; then non-noble-metal materials, such as copper, aluminum, semiconductor, graphene and other materials, for plasmonic sensing are categorized and presented. Finally, a rational discussion about the future prospective of novel materials for plasmonic sensing is given.     

液相色谱-串联质谱法检测血清中15种甾体激素的动态变化

建立了用液相色谱-串联质谱检测血清中15种甾体激素的方法。在血清样品中加入含内标的乙腈沉淀蛋白质后,用100 mmol/L盐酸羟胺衍生,经Agilent-C18柱(50 mm×3.0 mm,2.7μm)分离,内标法定量。质谱分析采用电喷雾电离(ESI)正离子扫描,多反应监测(MRM)模式检测。数据显示,13种激素在0.05~20 ng/mL范围内线性关系良好(相关系数(R2)不小于0.995 6),检出限不大于1 ng/mL;皮质醇及脱氢表雄酮硫酸酯在50~2 000ng/mL范围内线性关系良好(R2不小于0.997 9),检出限不大于0.5 ng/mL。将该方法应用于女性月经周期激素变化规律的研究,结果表明,15种甾体激素在一个完整的月经周期内有不同特征的动态变化,其中雄激素在滤泡期的后期达到最高值,孕(雌)激素在黄体期达到最高值,而皮质激素则波动不明显。该方法灵敏度高、重复性好,为临床诊疗提供了参考。