不同波长激光辐照对痢疾杆菌生物学效应的影响

分别采用功率密度为1.7W/cm²、照射剂量为2000J/cm²的Ar⁺激光与LD激光辐照高耐药性的志贺氏福氏痢疾杆菌,波长较短的Ar⁺激光(488nm)所引起细菌的致死率与药敏实变率明显高于波长较长的LD激光(808nm),即波长较短的Ar⁺激光的辐照导致细菌耐药性显著降低.     

小分子阿特拉津和罂粟碱检测的免疫芯片技术研究

采用蛋白芯片竞争法对小分子半抗原的污染物进行检测。在获得特异性抗体的前提下,首先将阿特拉津半抗原进行了衍生化,然后将该衍生物和氨基罂粟碱分别与载体蛋白质卵清蛋白(OVA)进行偶联。实验证明新合成的完全抗原能够与其相应抗体发生特异性的结合。实验还对蛋白芯片检测阿特拉津进行了条件优化,其抗体固定化时间为2h,用卵清蛋白为封闭液的封闭时间为1h,样品稀释液pH值为8．0。并对阿特拉津及罂粟碱进行了定性、定量实验,结果表明：荧光信号强度随待测物浓度的降低而增强,有一定的线性趋势,阿特拉津检出限为0．001mg/L,罂粟碱检出限为0．01mg/L。     

Determination of oleanolic and ursolic acid in Chinese herbs using HPLC and γ-CD as mobile phase modifier

To separate and determine oleanolic acid and ursolic acid, a rapid and accurate HPLC using γ‐CD as the mobile phase additive was developed. The effect of CD nature and concentration, and the acidity of the mobile phase on the chromatographic behavior of two bioactive triterpenes were systematically studied. Two bioactive triterpenes were completely separated (R = 3.11) on a Kromasil^® C₁₈ column (150×4.6 mm id, 5 μm) with the mobile phase consisting of acetonitrile/0.1% phosphoric acid with 2 mM γ‐CD as the mobile phase modifier (60:40, v/v). The flow rate was set at 1.0 mL/min and the eluent was detected at 210 nm for two bioactive triterpenes. The linearity of the method was excellent (r=0.9999) over the studied range of 6–300 μg/mL for oleanolic acid, and 12–600 μg/mL for ursolic acid. The LOD and LOQ were 1.5 and 5.0, 1.0 and 3.0 μg/mL for oleanolic acid and ursolic acid, respectively. The optimized method was successfully applied to separate and determine two bioactive triterpenes in five Chinese herbs. It is concluded that this method could be used for rapid and accurate qualitative and quantitative analysis of the two bioactive triterpenes in Chinese herbs.     

An integrated strategy for the geographical origin traceability of Goji berries by antioxidants characteristic fingerprint based online ultra-performance liquid chromatography-2,2-diphenyl-1-picrylhydrazyl- photodiode array detector-mass spectrometry combined with multivariate statistics analysis

Goji berries are now becoming increasingly popular in the human diet due to their potential health benefits. Unscrupulous traders deliberately mislabel with certain origins to gain illegal profits, which seriously affected the consumers’ benefits. In this study, an online ultra-performance liquid chromatography-2,2-diphenyl-1 -picrylhydrazyl-photodiode array detector-electrospray ionization-quadrupole time of flight mass was developed for rapid screening and identification of the antioxidants from Goji berry; then, the antioxidants characteristic fingerprint was established and explored in the origins discrimination of Goji berries from China combined with multivariate statistics analysis. As a result, twenty-eight compounds were screened from Goji berry extract, 19 of which were identified by accurate molecular and ultraviolet information according to references. Principal components analysis and partial least squares discrimination analysis achieved the accurate classification from the four regions, eight compounds were selected as origin-related antioxidant markers with variable importance in projection >1 and one-way analysis of variance (P<0.05), including rutin, rutin di-hexose, P-coumaric acid tri-hexose, dicaffeoylquinic acid isomer, Quercetin-rhamno-di-hexoside, peak14, peak16, and peak27. This study provides a feasible strategy for the geographical origins discrimination of Goji berries based on antioxidant ingredients difference and will be helpful for improving the quality control level of Goji berries.     

流动注射蒸气发生原子吸收光谱测定痕量铜

建立了流动注射蒸气发生原子吸收光谱测定铜的新方法。使含有微量邻菲咯啉的样品溶液与硼氢化钠溶液汇合并反应生成蒸气态物质。在Ar载气下随反应液进入气液分离器分离 ,并进入石英管原子化器在 1 0 0 0℃下检测。在 5 0 0 μL进样体积下 ,铜的检出限为 1 8μg·L- 1 ,相对标准偏差为 2 6%(n =1 1 ,c=1 0 0 μg·L- 1 )。采样频率为 1 4 4样·h- 1 。分析标准参考物质大米粉和头发样品中的铜 ,结果与标准值一致     

功能化硅壳荧光纳米粒的细胞吞噬研究

合成了氨基聚酰胺-胺(PAMAM(G1.0))和酯基(PAMAM(G1.5))功能化的两种硅壳荧光纳米粒,通过透射电镜(TEM)、纳米粒度及动电位测定仪(zeta电势)、傅立叶红外光谱仪(FTIR)和热失重分析仪(TGA)进行表征;通过透射电镜(TEM)、共聚焦显微镜(CLSM)、细胞计数试剂盒(CCK-8)实验、流式细胞计数法评价两种硅壳荧光纳米粒进入9L细胞能力的大小、在细胞内的分布情况以及细胞毒性.TEM分析表明,修饰的硅壳纳米粒大小约为60 nm左右,pH=7.4,氨基功能化的纳米粒zeta电势为+19.08,酯基功能化的为-9.01;FTIR和TGA实验进一步证明两种纳米粒被氨基和酯基的功能化.TEM和CLSM结果表明纳米粒主要存在细胞浆中,且能被溶酶体吞噬.CCK-8结果显示两种纳米粒的浓度高达1 mg/mL时仍无明显的毒性作用,且有促细胞增殖作用.流式细胞计数结果表明,细胞摄取纳米粒呈浓度和时间依赖性,氨基比酯基修饰的纳米粒更易进入细胞.     

Investigation on defects in Lu2SiO5:Ce crystals grown by Czochralski method

Cerium‐doped lutetium oxyorthosilicate crystals (Lu₂SiO₅:Ce) with dimension of ∅︁50 × 60 mm were grown by Czochralski method from an inductively heated iridium crucible. The vaporized substance during growth was examined with XRD and proved to be SiO₂. The vertical and the screw strips existing on the surface of the boule were observed with optical microscope and tested with electron microprobe. They are confirmed to be iridium from the crucible and harmful to the crystal growth. The cleavage orientation of LSO was proved to be (110) and it is one of factors to cause crystal cracking. The scattering particles in LSO crystals are analyzed to be mainly composed of Lu₂O₃ inclusions. Two possible origins on these inclusions are proposed. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Numerical study of electroosmotic slip flow of fractional Oldroyd-B fluids at high zeta potentials

In this paper, an investigation of the electroosmotic flow of fractional Oldroyd-B fluids in a narrow circular tube with high zeta potential is presented. The Navier linear slip law at the walls is considered. The potential field is applied along the walls described by the nonlinear Poisson–Boltzmann equation. It's worth noting here that the linear Debye–Hückel approximation can't be used at the condition of high zeta potential and the exact solution of potential in cylindrical coordinates can't be obtained. Therefore, the Matlab bvp4c solver method and the finite difference method are employed to numerically solve the nonlinear Poisson–Boltzmann equation and the governing equations of the velocity distribution, respectively. To verify the validity of our numerical approach, a comparison has been made with the previous work in the case of low zeta potential and the excellent agreement between the solutions is clear. Then, in view of the obtained numerical solution for the velocity distribution, the numerical solutions of the flow rate and the shear stress are derived. Furthermore, based on numerical analysis, the influence of pertinent parameters on the potential distribution and the generation of flow is presented graphically.     

Effect of magnetic field on electroosmotic flow of viscoelastic fluids in a microchannel

Electroosmotic flow is an efficient transportation technology driven by applying an external electric field across the microchannel, which has a great potential for future application. This work is presented to study the unsteady electroosmotic flow of viscoelastic fluids combined with a constant pressure gradient and a vertical magnetic field through a parallel plate microchannel. For the reason that the upper and bottom walls of the parallel plate microchannel in microfluidic devices can be made of different materials, this leads to different hydrophobic properties, asymmetric zeta wall potentials, and different slip boundary conditions. The Navier slip model with different slip coefficients at walls is considered. The generalized Maxwell fluid with fractional derivative is adopted for the constitutive equation of the fluid. The analytical and numerical solutions of velocity are derived by employing the integral transform method and finite difference method, respectively. Excellent agreement is found between the numerical solutions and analytical solutions. Finally, the effects of fractional parameter , relaxation time , slip coefficients and , the ratio of wall zeta potentials , Hartmann number , and electrical field strength parameter on velocity profiles are interpreted graphically in detail.     

膜片电极支撑自组装双层脂膜中短杆菌肽离子通道的形成

通过一个两步程序在膜片电极尖端形成自组装双层脂膜：（1）膜片电极尖端沾取成膜液；（2）将吸附成膜液的尖端浸入电解液中，排除尖端多余的成膜液，通过电学方法监测双层脂膜的形成。将短杆菌肽通道蛋白分散在成膜液和电解质溶液中，在制备膜片电极支撑双层脂膜过程中，短杆菌肽重组到双层脂膜中形成离子通道，对通道的一般特性进行了研究，并观察到通道开放和关闭的现象。