Quantum Watermark Algorithm Based on Maximum Pixel Difference and Tent Map

International Journal of Theoretical Physics - A new quantum watermark algorithm is presented by combining maximum pixel difference partitioning with the least significant bit substitution...     

Various exact analytical solutions of a variable-coefficient Kadomtsev–Petviashvili equation

Nonlinear Dynamics - Under investigation is a generalized (3 + 1)-dimensional variable- coefficient Kadomtsev– Petviashvili equation in fluid mechanics. Various exact analytical solutions are...     

Recyclable and reusable Pd(OAc)2/PPh3/PEG‐2000 system for homocoupling reaction of arylboronic acids under air without base

A stable and efficient Pd(OAc)₂/PPh₃/PEG‐2000 catalytic system for homocoupling of arylboronic acids has been developed. In the presence of Pd(OAc)₂ and PPh₃, the homocoupling reaction of arylboronic acids was carried out smoothly in PEG‐2000 at 70 °C under air without base to afford a variety of symmetric biaryls in good to excellent yields. The isolation of the products was readily performed by extraction with diethyl ether, and the Pd(OAc)₂/PPh₃/PEG‐2000 system could be easily recycled and reused six times without significant loss of catalytic activity. Copyright © 2014 John Wiley & Sons, Ltd.     

Comprehensive profiling and evaluation of the alteration of RNA modifications in thyroid carcinoma by liquid chromatography-tandem mass spectrometry

RNA molecules contain diverse modifications that display important functions in a variety of physiological and pathological processes. So far over 150 chemical modifications have been characterized to be present in various RNA species, such as in messenger RNA (mRNA), ribosomal RNA (rRNA), and transfer RNA (tRNA). Previous studies revealed that certain RNA modifications were correlated to specific human diseases, indicating RNA modifications could serve as the potential indicator of human diseases. However, systemic investigation of the alteration of RNA modifications in different RNA species of carcinoma tissues are still lacked. Herein, we carried out the comprehensive profiling and evaluation of the alteration of RNA modifications in thyroid carcinoma by liquid chromatography-tandem mass spectrometry (LC-ESI-MS/MS) analysis. The developed method allowed us to simultaneously detect 48 different types of RNA modifications. Using this method, we detected 10, 15, 14, and 25 modifications in mRNA, 18S rRNA, 28S rRNA and small RNA (< 200 nt), respectively. Compared to the normal tissues, we revealed a total of 14 RNA modification exhibited significant increase and 2 RNA modifications showed significant decrease in thyroid carcinoma tissues. Our study provided the first comprehensive profile as well as the alteration of modifications in different RNA species in thyroid carcinoma and matched tumor-adjacent normal tissues. The altered pattern RNA modifications may serve as the indicator of thyroid carcinoma. Moreover, this study may promote the in-depth understanding of the regulatory roles of RNA modifications in thyroid carcinoma.     

Quantitative Analysis of Al in Flour Products by Laser-Induced Breakdown Spectroscopy Combined with Partial Least Squares

Journal of Applied Spectroscopy - Based on partial least squares (PLS) analysis, the effects of different smoothing points and different preprocessing methods on the accuracy and precision of the...     

Graphene and graphene like 2D graphitic carbon nitride: Electrochemical detection of food colorants and toxic substances in environment

Excessive consumption of substances such as food colorants, exposure to doses of metal ions, antibiotic residues and pesticides residues above maximum tolerance limit have a detrimental effect on human health. Hence in detecting these harmful substances, the development of sensitive, selective and convenient analytical tools is an essential step. Graphene and graphene like 2D graphitic carbon nitride have shown great promise in the development of electrochemical sensors for determining the levels of these substances in different samples. In this paper, graphene and graphene like 2D graphitic carbon nitride applications on the determination of various food colorants in foods and drinks such as azo dyes (tartrazine, allura red, amaranth, carmine and sunset yellow); metal ions contaminants, antibiotic and pesticide residues in the environment are reviewed.     

单层n型MoS2/p型c-Si异质结太阳电池数值模拟

单层二硫化钼(MoS₂)是一种具有优异光电性能的半导体材料,在太阳能能量转换中表现出很大的应用潜力。本文基于AMPS模拟软件,对单层n型MoS₂/p型c-Si异质结太阳电池进行了数值模拟与分析。通过模拟优化,n型MoS₂的电子亲和能为3.75 eV、掺杂浓度为10¹⁸ cm^-3,p型c-Si的掺杂浓度为10¹⁷ cm^-3时,太阳电池能够取得最高22.1%的转换效率。最后模拟了n型MoS₂/p型c-Si异质结界面处的界面态对太阳电池性能的影响,发现界面态密度超过10¹¹ cm^-2·eV^-1时会严重影响太阳电池的光伏性能。     

光学共振增强的表面铯激活银纳米结构光阴极

金属光阴极因其超短脉冲发射和运行寿命长的特性从而具有重要应用价值,但是较高的功函数和较强的电子散射使其需要采用高能量紫外光子激发且光电发射量子效率极低.本文利用Mie散射共振效应增强银纳米颗粒中的局域光学态密度,提升光吸收率和电子的输运效率,并利用激活层降低银的功函数,从而增强光阴极在可见光区的量子效率.采用时域有限差分方法分析银纳米球阵列的光学共振特性,采用磁控溅射和退火工艺在银/氧化锡铟复合衬底上制备银纳米球,紧接着在其表面沉积制备铯激活层,最后在高真空腔体中测试光电发射量子效率.实验结果表明平均粒径150 nm的银纳米球光阴极在425 nm波长的量子效率超过0.35%,为相同激活条件下银薄膜光阴极的12倍,峰值波长与理论计算的Mie共振波长相符合.     

Fused vs. spiro: Kinetic,not thermodynamic preference may direct the reaction of α-carbonyl oxonium ylides

Rh(II)-catalyzed decomposition of certain cyclic α-diazocarbonyl compounds in the presence of cyclic ethers has been shown to give bicyclic ring expansion products. These are thought to arise from a [1,4]-alkyl shift toward the carbonyl oxygen atom and are in contrast with the recently observed spirocyclic products of a Stevens-type [1,2]-alkyl shift within the postulated oxonium ylide intermediate. Quantum chemical calculations performed at the B3LYP/6-31G* level of theory showed that the former reaction pathway (toward fused bicycles) is kinetically preferred.