Depletion of high-abundance proteins from human plasma using a combination of an affinity and pseudo-affinity column

Human serum albumin (HSA) and immunoglobulin G (IgG) represent over 75% of all proteins present in human plasma. These high-abundance proteins prevent the detection of low-abundance proteins which are potential markers for various diseases. The depletion of HSA and IgG is therefore essential for further proteome analysis. In this paper we describe the optimization of conditions for selective depletion of HSA and IgG using affinity and pseudo-affinity chromatography. A BIA Separations CIM (convective interaction media) Protein G disk was applied for the removal of IgG and the Mimetic Blue SA A6XL stationary phase for the removal of HSA. The binding and the elution buffer for CIM Protein G disk were chosen on the basis of the peak shape. The dynamic binding capacity was determined. It was shown to be dependent on the buffer system used and independent of the flow rate and of the concentration of IgG. Beside the binding capacity for the IgG standard, the binding capacity was also determined for IgG in human plasma. The Mimetic Blue SA A6XL column was characterized using human plasma. The selectivity of the depletion was dependent on the amount of human plasma that was loaded on the column. After the conditions on both supports had been optimized, the Mimetic Blue SA A6XL stationary phase was combined with the CIM Protein G disk in order to simultaneously deplete samples of human plasma. A centrifuge spin column that enables the removal of IgG and HSA from 20 μL of human plasma was designed. The results of the depletion were examined using sodium dodecyl sulfate polyacrylamide gel electrophoresis and two-dimensional gel electrophoresis.     

镁-美他环素胶束体系荧光特性及美他环素的测定

研究了在金属离子存在下美他环素在胶柬体系中的荧光特性,实验结果表明：在pH 9.50～11.30的H3PO4-HAc-H3BO3-NaOH缓冲溶液中,镁离子和非离子表面活性剂曲通X-100对美他环素的荧光具有显著的协同增敏作用.据此建立了测定药物制剂中美他环素的荧光光谱法.定量线性范围为0.16～16μg/mL,检出限为0.0036μg/mL,相对标准偏差为1.9%.     

Sr(NO3)2·DCH18C6配合物晶体结构与辐射稳定性

二环己基-18-冠-6（DCH18C6）可以有效地从高放废液中分离⁹⁰Sr,对于减小放射性废物的危害和实现高放废物的减容有重要意义. 由于在实际应用中DCH18C6处于射线照射下,其结构可能会被破坏并引起络合能力的变化,因此有必要对该配合物的辐射稳定性进行研究. 本文合成了Sr（NO₃）₂·DCH18C6 配合物晶体,并通过单晶X射线衍射（XRD）与扩展X射线吸收精细结构谱（EXAFS）等方法进行了表征,确定Sr²⁺与周围氧原子的配位数为10,Sr―O平均键长约为0.268 nm/0.266 nm（XRD/EXAFS）. 配位原子来自DCH18C6 的六个氧原子以及两个作为双齿配体的硝酸根的四个氧原子. 对该配合物晶体在空气中进行γ辐照,EXAFS结果表明吸收剂量为400 kGy时,Sr―O键长及配位数没有发生变化,配位结构没有被破坏,具有很好的耐辐照稳定性. 显微红外光谱（Micro-FTIR）结果进一步证明辐照后冠醚环的部分C―H 键氧化为羟基或羰基,但并不影响DCH18C6与Sr²⁺的配位结构.     

三江平原湿地非使用价值支付意愿的影响因素

为了更好地保护三江平原湿地生态系统,应用条件价值评估法(CVM)这一当前国际上流行的生态系统经济价值评价方法,对三江平原湿地的非使用价值进行评价.研究中采用实地调研的方式,进行支付意愿问卷调查,共发放支付卡式CVM问卷552份,回收有效问卷513份.得出三江平原湿地2007年人均支付意愿为71.66元/年.通过对问卷数据的描述性统计,得到支付意愿的分布情况和在各单一因素影响下的变化规律.用主成分分析简化影响因素,运用有序多分类Logit模型,得到在所有影响因素中,个人平均年收入、个人受教育程度以及个人环保态度是影响受访者对三江平原湿地非使用价值支付意愿的主要因素.研究结论使得三江平原湿地开发和保护价值比较成为可能,为政府制定相关政策提供理论基础与科学依据.     

微多孔介质非牛顿流体格子Boltzmann模拟

根据修正Blake-Kozeny方程对Herschel-Bulkley模型的非牛顿流体在微多孔介质中流动的定量描述,通过增加外力项建立了非牛顿流体在宏观多孔介质中的格子Boltzmann模型,并将该模型应用到平板多孔介质中非牛顿流体的电渗驱动流模拟。对多孔介质渗透性参数和非牛顿流体流变性参数的影响进行模拟和分析,获得了各种参数对多孔介质中非牛顿流体流动速度的影响规律。     

Meronlike solutions of conformally covariant coupled nonlinear field equations

We derive a new class of solutions of conformally covariant coupled spinor and scalar equations including a nonlinear spinor self-coupling term, for which the energy-momentum density is nonzero, but the total energy is zero (“meronlike” solutions).     

高能带电粒子直接产生电子对

本文叙述利用场强为6200高斯的磁云室,对级联簇射中的能量大于30兆电子伏的电子在铝中直接产生电子对的平均总截面进行了测量。实验上总共找到真正由电子产生的电子三岔8.1个,相应于三岔产生的平均自由路程为672±585厘米或平均总截面为(0.25±0.22)×10^-25厘米²。在数据处理中,对假三岔数目的除去作了应有的适当考虑。此外对Bhabha及Murota等的总截面公式也作了适合于于我们实验具体情况的修正,并算出总截面值,最后将它同实验值作了比较。结果我们认为实验上测得的值和Murota等的总截面值较为接近,但也不与Bhabha的截面值矛盾。     

将冷等离子体研究成果引入到实验教学的一种尝试

介绍了将冷等离子体科研成果引入到物理实验教学的两个实验，使学生了解到等离子体技术在材料表面改性中的具体应用，这不仅增强了学生的学习兴趣，而且开阔了学生的视野。     

Effect of Higher-Order Terms on Nonlinear Schrodinger Dark Solitons in Optical Fibres

We solve the nonlinear Schrodinger equation with higher order terms, which describes the propagation of femtosecond pulses in optical fibres, by means of a direct perturbation method for dark solitons. An exact dark-soliton solution of the higher order nonlinear Schroedinger equation is found, provided that parameters satisfy certain conditions. The soliton＇s velocity with the high order effects as well as the formula for calculation of the first-order correction representing the perturbation-induced radiative field is presented.     

Identification of proteins interacting with ammodytoxins in Vipera ammodytes ammodytes venom by immuno-affinity chromatography

In order to perform their function, proteins frequently interact with other proteins. Various methods are used to reveal protein interacting partners, and affinity chromatography is one of them. Snake venom is composed mostly of proteins, and various protein complexes in the venom have been found to exhibit higher toxicity levels than respective components separately. Complexes can modulate envenomation activity of a venom and/or potentiate its effect. Our previous data indicate that the most toxic components of the Vipera ammodytes ammodytes (Vaa) venom isolated so far—ammodytoxins (Atxs)—are contributing to the venom’s toxicity only moderately; therefore, we aimed to explore whether they have some interacting partner(s) potentiating toxicity. For screening of possible interactions, immuno-affinity chromatography combined with identification by mass spectrometry was used. Various chemistries (epoxy, carbonyldiimidazole, ethylenediamine) as well as protein G functionality were used to immobilize antibodies on monolith support, a Convective Interaction Media disk. Monoliths have been demonstrated to better suit the separation of large biomolecules. Using such approach, several proteins were indicated as potential Atx-binding proteins. Among these, the interaction of Atxs with a Kunitz-type inhibitor was confirmed by far-Western dot-blot and surface plasmon resonance measurement. It can be concluded that affinity chromatography on monolithic columns combined with mass spectrometry identification is a successful approach for screening of protein interactions and it resulted with detection of the interaction of Atx with Kunitz-type inhibitor in Vaa venom for the first time.