A Sensitive Signal-off Electrochemical Aptasensor for Thrombin Detection using PB−Au@MoS2 Nanomaterial as Both Platform and Signal Reporter

Human serum is one of the effective samples for point-of-care testing (POCT). Sensitive and quick determination of thrombin content in human serum samples is important. An electrochemical aptasensor based on Prussian blue and Au nanoparticles loaded MoS₂ nanoflowers (PB−Au@MoS₂) hybrid was constructed. By using PB−Au@MoS₂ as both a substrate and a signal reporter, this aptasensor could demonstrate excellent performance for thrombin detection with a detection linear range from 0.01 pM to 30 nM and detection limit down to 1 fM. This work may provide a strategy to establish effective and sensitive sensing devices for thrombin in clinical diagnosis.     

A biosynthetic route to photoclick chemistry on proteins

Light-induced chemical reactions exist in nature, regulating many important cellular and organismal functions, e.g., photosensing in prokaryotes and vision formation in mammals. Here, we report the genetic incorporation of a photoreactive unnatural amino acid, p-(2-tetrazole)phenylalanine (p-Tpa), into myoglobin site-specifically in E. coli by evolving an orthogonal tRNA/aminoacyl-tRNA synthetase pair and the use of p-Tpa as a bioorthogonal chemical "handle" for fluorescent labeling of p-Tpa-encoded myoglobin via the photoclick reaction. Moreover, we elucidated the structural basis for the biosynthetic incorporation of p-Tpa into proteins by solving the X-ray structure of p-Tpa-specific aminoacyl-tRNA synthetase in complex with p-Tpa. The genetic encoding of this photoreactive amino acid should make it possible in the future to photoregulate protein function in living systems.     

Sensitive Detection of Luteolin Using Thioglycolic Acid–Capped Cadmium Telluride/Cadmium Sulphide Quantum Dots as the Fluorescent Probe

ABSTRACT

A sensitive and simple method for the determination of luteolin (LTL) was developed based on the fluorescence quenching effect of LTL for thioglycolic acid–capped (TGA-capped) CdTe/CdS quantum dots (QDs). Under optimum conditions, a good linear relationship was obtained from 0.3 to 20.0 µg · mL^?1 with a correlation coefficient of 0.9972, and the detection limit was 7.2 ng · mL^?1. The fluorescence quenching mechanism has been proposed on the basis of electron transfer supported by ultraviolet-visible (UV-Vis) absorption, fluorescence (FL) spectroscopy. The proposed method was successfully applied to the determination of LTL in commercial capsules and human urine samples. It manifested several advantages such as high sensitivity, short analysis time, low cost, and ease of operation.     

Crystallization of CaCO3 in the presence of sulfate and additives: experimental and molecular dynamics simulation studies

The effects of sulfate and BHTPMP (Bis (hexamethylene) triaminepentakis (methylene phosphonic acid)) on the crystallization rate, phase composition and morphology of calcium carbonate have been studied. It was observed that sulfate reduces the nucleation rate and favors the formation of aragonite form in the calcium carbonate precipitate. Moreover, in the presence of sulfate the rhombohedral morphology of the calcite crystals is modified, and during the formation of calcite, the development of {104} faces are more significantly prohibited than {110} faces. In the presence of sulfate together with BHTPMP, the crystallization process is inhibited and the modified morphology and the dominant calcite form are observed in the solid. The results from molecular dynamics simulations show the more strong combination of sulfate with calcite surface, in particular the {104} face, in comparison with the aragonite surface. The strong interaction of BHTPMP with sulfate and the aragonite surface favors the formation of the dominant calcite phase in the precipitate.     

风险型决策的可信度研究

本文提出了风险型决策的可信度以及最优决策的结构概念，分析了影响决策可信度的几个主要因素，给出了可信度的计算函数及其基本性质，举例说明了提高决策可信度的方法。     

电动势的测量和计算

本文详细介绍了测量电动势的四种典型电路以及每种电路电动势的测量和计算的具体方法     

Characterization of corrosion products formed on the surface of carbon steel by Raman spectroscopy

Corrosion of carbon steel in seashore salty soils containing 10, 20, and 34 wt% (saturated) water was investigated. The corrosion rate was measured and corrosion products were analyzed using Raman spectroscopy. It was found that carbon steel in the soil with 10 wt% water content had the largest corrosion rate and the corrosion was dominated by localized corrosion. The corrosion rate drops dramatically and turns to be general corrosion with increase of water content. The corrosion products in the soil with 20 and 34 wt% water content are mainly composed of α‐FeOOH, while in the soil with 10 wt% water content, the products show a delaminated structure of two layers with the inner layer mainly consisting of α‐FeOOH and the outer layer composed of Fe₂O₃ and Fe₃O₄. Copyright © 2008 John Wiley & Sons, Ltd.     

非线性晶体三波互作用允许参量的修正计算

采用传统级数展开方法计算晶体非线性三波互作用的允许参量,利用定义通过计算机数值模拟进行了精确计算,修正了传统计算结果,发现晶体在产生二次谐波时,在某些角度存在很宽的允许波长峰,超过传统文献值约几十倍。研究表明,在产生二次谐波时,10mm长的晶体在某些波段获得100mm以上的允许倍频带宽是可能的,并提出了移动这些宽带的方法。