Thermally Induced Measurement Error by a Water-Cooled Enthalpy Probe

Errors in stagnation-pressure measurement, due to a large temperature gradient at the face of a water-cooled enthalpy probe, were experimentally measured and numerically simulated. Two probes were used to measure the stagnation-pressure in a dc plasma jet; a standard water-cooled enthalpy probe and an uncooled ceramic (Thoria) probe. There was a maximum difference of 10% between the two measurements, with the water-cooled probe measuring lower pressures. Numerical simulations of plasma flow around the probe showed that the magnitude of the error depends on the thickness of the thermal boundary layer. The measurement error causes a maximum of 3% error in velocity measurements, using the Bernoulli equation. This error is no worse than other measurement errors associated with water-cooled enthalpy probe meaurements.     

A selective fluorescent probe for La and Y based on calix[6]arene

A new fluorescent probe based on calix[6]arene functionalized with three naphthoic acid groups was synthesized and showed selective fluorescence enhancement in the presence of La³⁺ and Y³⁺. In addition, the fluorescence enhancement behaviors depended on the pH values of the solution.     

直肠癌患者头发微量元素分析

应用装存EPM-810Q电子探针的扫描分析电镜，对53例直肠癌患者作单根头发中镁、铝、镉，钙，铬、铁、铜、锌、铅、锰、硒11种微量元素分析。并与健康对照组进行比较，结果表明：直肠癌患者头发中镁、铝，钙含量明显低于正常。     

Detection of potential membrane receptor proteins concerning circadian rhythmic leaf movement of legumes using novel photoaffinity probe compounds

Circadian rhythmic plant leaf movement, called nyctinasty, is controlled by a time-course change in the internal concentration of the leaf-movement factor in the plant body. We report that specific binding protein (210 and 180 kDa) for a leaf-movement factor, potassium lespedezate, is contained in the plasma membrane of the plant motor cell. These proteins would be potential receptors for leaf-movement factor to control the leaf movement.     

固氮酶及合成氨Fe催化剂中N2的络合位

用乙烯为探针研究了固氮酶中Ｎ２的键合位，结果表明，乙烯不能与Ｎ２在固氮酶体系中相竞争，提出Ｎ２在固氮酶中键合位很可能是蛋白键合ＦｅＭｏ－ｃｏ笼内６Ｆｅ位的μρ（η＾２，ε４）ｔ ３Ｆｅ＋１Ｍｏ位的μ４（η＾３，ε）方式，而不是笼口２Ｆｅ位的μ２（η＾２）方式，在合成氨Ｆｅ催化剂中Ｎ２的络事方式可能是μ６（η＾３，ε３ ）。     

Determining PPARγ-ligand binding affinity using fluorescent assay with cis-parinaric acid as a probe

Upon the study of small-molecules binding to proteins, the traditional methods for calculating dissociation constants (Kd and Ki) have shortcomings in dealing with the single binding site models. In this paper, two equations have been derived to solve this problem. These two equations are independent of the total concentration or initial degree of saturation of receptor and the activity of the competitive molecule. Through nonlinear fitting against these two equations, Kd value of a probe can be obtained by binding assay, and Ki value of a ligand can be obtained by competitive assay. Moreover, only the total concentrations of receptor([R]t), ligand([L]t) and probe([P]t) are required for the data fitting. In this work, Ki values of some typical ligands of PPARγ were successfully determined by use of our equations, among which the Ki value of PPARγ-LY171883 was reported for the first time.     

溶剂聚合膜pH电极作内电极的气敏电极的研究

研究了以中性载体为活性物的石墨内导平头溶剂聚合膜(SPM)pH电极作内电极的二氧化碳和氨气敏电极。电极的性能取决于中性载体的特性,其中以菸酸十八酯为内电极膜活性物的二氧化碳气敏电极和以二辛基十八胺为活性物的氨气敏电极性能较佳。二氧化碳气敏电极用作丙酮酸脱羧酶酶电极的原电极,其性能院于传统的以玻璃pH电极作内电极的二氧化碳气敏电极。     

新型酰腙类荧光探针的合成及其对Al(Ⅲ)的传感性质

合成了两个酰腙类荧光探针1和2,在DMSO-H_2O(7∶3,体积比)体系中,两者分别在478 nm和460 nm处对Al~(3+)具有较好的荧光选择识别作用。Job's法、核磁滴定、质谱分析表明,探针1和2与Al~(3+)的配位比均为1∶2,且对Al~(3+)的检出限分别为9.58×10~(-8) mol/L和6.52×10~(-8) mol/L。同时提出了探针1和2对Al~(3+)的荧光传感机理。实际应用研究表明,探针1和2可用于河水和自来水中一定浓度范围内Al~(3+)的检测。     

Polymer drying. VI. EPR spin-probe studies on swelled poly(styrene-co-divinylbenzene)

The electron paramagnetic resonance (EPR) signal and the residual number (α_t) of volatile molecules per phenyl group of poly(styrene-co-divinylbenzene) in samples that had been swelled to saturation in a dilute solution of a nitroxide spin-probe (TEMPO or 4-oxo-TEMPO), dissolved in a volatile liquid, were monitored simultaneously as the system containing excess liquid was allowed to evaporate to dryness. The results showed that the characteristic motionally narrowed three-line EPR spectrum began to change when α_t became equal to α_g (the number of sorbed molecules per phenyl group of polymer at liquid-saturation). The ratio of the intensity of the low-field and high-field hyperfine peaks relative to the middle peak decreased monotonically to an asymptotic limit that was attained when α_t became equal to α_g (the number of residual adsorbed molecules per phenyl group of polymer at completion of the transition from the rubbery state to the glassy state). The EPR hyperfine pattern, from which the rotational correlation times were estimated, changed most significantly as α_t decreased from α_G to α_g while exhibiting inflections at about α′_s and α′_g the compositions that mark, respectively, incipient desorption of adsorbed molecules and incipient transition from the rubbery state to the glassy state. The pattern between these inflections points, however, varied with the affinity of the solvent for the polymer.     

A quantitative method for dual‐pass electrostatic force microscopy phase measurements

Electrostatic force microscopy (EFM) has become a powerful tool for investigating charges on surfaces. The use of phase measurement in EFM is a direct and fast way to detect electrostatic force gradients, but only qualitatively. With the dual‐pass scheme, the phase signal at lifted height is often assumed to exclude any influences from the topography, but it does not. We report the collection of both topography and phase data by EFM on charged, micron‐sized metal wires. In order to quantify the electrostatic force, a cone model and finite element analysis are provided to integrate the force gradient from the phase signal. Copyright © 2007 John Wiley & Sons, Ltd.