Rapid detection of Escherichia coliform with a bulk acoustic wave sensor based on the gelation of Tachypleus amebocyte lysate

A new sensing method (BAW-TAL technique), which combined the bulk acoustic wave (BAW) technique with the gelation reaction of Tachypleus amebocyte lysate (TAL), was used for viscosity and density measurement and applied to the detection of Escherichia coliform (E. coli). This method depended on the fact that the viscosity and density of the mixture increased, and as a result, the resonance frequency decreased correspondingly after TAL was mixed with the heated E. coli solution that contained endotoxin. Results showed that the frequency shift was linearly related to the logarithm of E. coli concentration in the range of 2.7x10(4)-2.7x10(8) cells/ml. The correlation coefficient was 0.996. This BAW-TAL method was compared with the standard pour plate counts (PPC) method. The proposed method was much more rapid and simpler for detection of E. coli than the traditional methods.     

细胞动力学研究VIII.Na2SeO3对黑根菌作用特征

The Characteristics of the action of Na2SeO3 on Rhizopus nigrocans has been studied by means of microcalorimetry, the relationship between growth rate constants and the concentration of Na2SeO3 is
k=0.03608exp[-0.003608(c+8.60)2]
It was found that Na2SeO3 of low concentration has promoting action on the growth of Rhizopus nigrocans cells, and high concentration of Na2SeO3 has inhibitory action. The study has provided a lot of information on the bioaffect of selenium and the research of toxicology.     

When does gradient Ricci soliton have one end?

Annals of Global Analysis and Geometry - In this paper, we study a problem of finding compact hypersurfaces of prescribed mean curvature with free boundary in a ball. We transform the problem to an...     

钼钨铌磷杂多化合物的研究（Ⅰ）：杂多酸的合成和表征

提出了分步酸化一分步加料合成[PNb_2Mo_xW_(10-x)O_(40)]~(5-)(x=0,2,4,6)系列杂多酸的方法,给出了最佳配料比和生成反应的pH值,并进行了红外、紫外、极谱、电位滴定及热稳定性研究。     

Oligodeoxyfluorosides: Strong Sequence Dependence of Fluorescence Emission

We describe the properties of a series of oligomeric polyfluorophores assembled on the DNA backbone. The 11 oligomers (oligodeoxyfluorosides, ODFs), 4-7 monomers in length, were composed of only two fluorescent monomers and a spacer in varied sequences, and were designed to test how fluorescent nucleobases can interact electronically to yield complexity in fluorescence emission. The monomer fluorophores were deoxyribosides of pyrene and perylene, which emit light in violet and blue wavelengths, respectively. The experiments show that simple variation in sequence and spacing can dramatically change fluorescence, yielding emission maxima ranging from 380 to 557 nm and visible colors from violet to orange-red. Fluorescence lifetime data, excitation spectra, and absorption data point to a number of multi-fluorophore electronic interactions, including pyrene-pyrene and perylene-perylene excimers, pyrene-perylene exciplexes, as well as monomer dye emissions, contributing to the final spectral outcomes. Thus, two simple fluorophores can be readily combined to give emissions over much of the visible spectrum, all requiring only a single excitation. The results demonstrate that fluorescent nucleobases in oligomeric form can act cooperatively as electronic units, and that fluorophore sequence in such oligomers is as important as fluorophore composition in determining fluorescence properties.     

铟(Ⅲ)-向红菲啰啉络合物极谱吸附波的研究

在pH=3.8的磷酸柠檬酸盐缓冲体系中,铟(Ⅲ)-向红菲(口罗)啉络合物在单扫描示波极谱仪上于-0.67 V(vs.SCE)处产生一灵敏的吸附还原波,其二阶导数波灵敏度高,波形好.峰电位Ⅰ~O_P与钢(Ⅲ)浓度在 2.0X10~(-8)~2.0X10~(-6)mol/L范围内呈良好的线性关系,其检测限为8X10~(-9)mol/L铟(Ⅲ).该法用于试剂氧化锌和镀膜玻璃中铟(Ⅲ)的恻定,结果较好.     

离线预富集电感耦合等离子体质谱法测定天然水体中溶解态硅

以Mg(OH)2共沉淀和阳离子交换树脂作为离线预富集方法,建立了天然水体中溶解态硅电感耦合等离子体质谱(ICP-MS)测定方法。实验采用NaOH作为Mg(OH)2沉淀引发剂,以共沉淀方式将溶解态硅元素从天然水体中分离富集,再利用阳离子交换树脂将基体Mg2 清除,并对洗脱液流速、共沉淀碱度等条件进行优化选择。结果显示:Mg(OH)2共沉淀步骤可定量回收溶解态硅,控制溶液通过阳离子交换树脂的速率可将硅元素与基体Mg2 完全分离而不会造成损失。不同基体的水样的加标回收率为99%~105%,方法检出限为4.5μg/L(3S,n=8),方法精密度RSD小于3%。     

REDUCING NONSELECTIVE PROTEIN ADSORPTION AND CELL ADHESION ON POLYACRYLONITRILE FILMS BY COPOLYMERIZATION OF ACRYLONITRILE WITH α-ALLYL GLUCOSIDE

In this work, the surface properties of novel sugar-containing polymers, α-allyl glucoside (AG)/acrylonitrile (AN)copolymers, were studied by contact angle, protein adsorption and cell adhesion measurements. It was found that the contactangle of the copolymer films decreased from 68° to 30° with the increase of AG content in the copolymer. The adsorptionamount of bovine serum albumin (BSA) and the adhesive macrophage onto the film surface also decreased significantly withincreasing α-allyl glucoside content from 0 to 42 wt% in the copolymer. These preliminary results reveal that both thehydrophilicity and the biocompatibility of polyacrylonitrile-based membranes could be improved by copolymerizing acrylonitrile with vinyl carbohydrates.     

混合型杂多化合物Mx[GaW9M3O40]·nH2O的合成和性质

本文报道了M_x[GaW₉M₃^′O₄₀]nH₂O(M′=Mo,V,Ti,Fe(Ⅲ),Co(Ⅱ),Ni(Ⅱ),Mn(Ⅱ);M=k,Na,Gua,Me₄N,Et₄N,Bu₄N)的合成。通过元素分析,阴离子电荷的确定,极谱、IR及UV光谱、可见光谱、ESR、磁化率测定对其进行了表征。并研究了它们在水溶液中对酸碱的稳定性