Cyclodextrin derivatives functionalized highly sensitive chiral sensor based on organic field-effect transistor

Novel highly sensitive chiral organic field-effect transistors(COFET)were developed by directly assembling imidazolium3,5-dimethylphenylcabamoylated-β-cyclodextrin(lm^+-Ph-β-CD)and 3,5-dimethylphenylcarbamoylated-β-CD(Ph-β-CD)respectively onto the semiconductor layer as sensing units.The Im+-Ph-β-CD/COFET afforded better enantioselectivity and a lowest detection concentration of10^-18 L/mol as well as the potentiality in quantitative analysis of commercial medicines.     

Nonlinear frequency response analysis: a recent review and perspectives

The nonlinear frequency response analysis (NFRA) can be seen as an extension of electrochemical impedance spectroscopy. NFRA gives a full and detailed representation of the system response and can establish a connection between model parameters and the experimentally observed phenomena. In this article, different theoretical NFRA approaches and the most recent application examples are discussed. A simple electrochemical example is used to showcase the benefits and disadvantages of analyzing the system response by using different approaches. In addition, it was shown how to extract experimental harmonic values and analyze them.     

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.     

Arrival time distributions of product ions reveal isomeric ratio of deprotonated molecules in ion mobility–mass spectrometry of hyaluronan‐derived oligosaccharides

Hyaluronic acid is a naturally occurring linear polysaccharide with substantial medical potential. In this work, discrimination of tyramine‐based hyaluronan derivatives was accessed by ion mobility–mass spectrometry of deprotonated molecules and nuclear magnetic resonance spectroscopy. As the product ion mass spectra did not allow for direct isomer discrimination in mixture, the reductive labeling of oligosaccharides as well as stable isotope labeling was performed. The ion mobility separation of parent ions together with the characteristic fragmentation for reduced isomers providing unique product ions allowed us to identify isomers present in a mixture and determine their mutual isomeric ratio. The determination used simple recalculation of arrival time distribution areas of unique ions to areas of deprotonated molecules. Mass spectrometry data were confirmed by nuclear magnetic resonance spectroscopy. Copyright © 2015 John Wiley & Sons, Ltd.     

中学化学教学中的科学思维与逻辑辨析

化学是一门具有创造性的基础科学,是环境、生命、医药、材料等科学的基础,在思维逻辑上彰显和蕴含了丰富的科学思维方法。系统总结化学科学思维方法,可以有效破解中学化学学习中的“繁,难,乱”。在多年的教学实践中,提出了化学科学多向思维方法体系,强调多层次思维过程中对多因素的立体逻辑思维辨析。重点介绍了与中学化学教学相关的零阶、初阶、中阶和高阶逻辑思维辨析的内涵,期望化学教学中重视化学思维逻辑过程,实现化学教与学在思维模式上的深层次发展与提升。     

Discrimination of Beers by Cyclic Voltammetry Using a Single Carbon Screen-printed Electrode

A fast, simple and costless methodology without sample pre-treatment is proposed for the discrimination of beers. It is based on cyclic voltammetry (CV) using commercial carbon screen-printed electrodes (SPCE) and includes a correction of the signals measured with different SPCE units. Data are submitted to partial least squares discriminant analysis (PLS−DA) and support vector machine discriminant analysis (SVM−DA), which allow a reasonable classification of the beers. Also, CV data from beers can be used to predict their alcoholic degree by partial least squares (PLS) and artificial neural networks (ANN). In general, non-linear methods provide better results than linear ones.     

Electrochemical Characterization of Coinage Techniques the 17th Century: The maravedís Case

The voltammetry of immobilized particles (VIMP) methodology was applied to the discrimination of Spanish maravedis produced in 10 different mints between 1661 and 1664 using characteristic signatures for the reduction of cuprite and tenorite in the patina of the coins and catalytic effects on the hydrogen evolution reaction (HER). The variation of the apparent tenorite/cuprite ratio with depth was fitted to potential laws differing from one mint to another for A Coruña, Burgos, Córdoba, Cuenca, Granada, Madrid, Trujillo, Segovia, Sevilla and Valladolid coins. Electrochemical data permitted to detect the changes in the composition (with lowering of the silver content) and manufacturing technique (from hammer to mill) occurring in this historical period.     

The cultural Red King effect

Why do minority groups tend to be discriminated against when it comes to situations of bargaining and resource division? In this article, I explore an explanation for this disadvantage that appeals solely to the dynamics of social interaction between minority and majority groups—the cultural Red King effect (Bruner, 2017). As I show, in agent-based models of bargaining between groups, the minority group will tend to get less as a direct result of the fact that they frequently interact with majority group members, while majority group members meet them only rarely. This effect is strengthened by certain psychological phenomenon—risk aversion and in-group preference—is robust on network models, and is strengthened in cases where preexisting norms are discriminatory. I will also discuss how this effect unifies previous results on the impacts of institutional memory on bargaining between groups.     

阵不变量匹配主动声呐目标深度辨识

水面/水下目标深度辨识可以在主动声呐探测过程中快速筛选感兴趣目标。根据目标多径返回信号到达时间与目标深度的关联性,该文提出了基于水平线阵的主动脉冲响应匹配目标深度辨识方法,该方法利用主动信号传播特性结合阵不变量理论提取脉冲响应,并与拷贝声场匹配实现目标深度估计。在校正了目标多径回波的方位变化后,该方法提取的时域特征较为稳定,并且只在时延估计距离处进行深度搜索。通过水平阵收集的宽带实验数据,在连续的多次回波中实现了对水面/水下目标92%的辨识成功率,验证了该方法在浅海环境下的目标深度估计能力。     

The Linear Optical Unambiguous Discrimination of Hyperentangled Bell States Assisted by Time Bin

A linear optical unambiguous discrimination of hyperentangled Bell states is proposed for two‐photon systems entangled in both the polarization and momentum degrees of freedom (DOFs) assisted by time bin. This unambiguous discrimination scheme can completely identify 16 orthogonal hyperentangled Bell states using only linear optical elements, where the function of the auxiliary entangled Bell state is replaced by time bin. Moreover, the possibility of extending this scheme for distinguishing hyperentangled Bell states in n DOFs is discussed, and it shows that $2^{n+k+1}$ hyperentangled Bell states in n ( $n\ge 2$) DOFs can be distinguished with k ( $k<n$) auxiliary entangled states of additional DOFs by introducing a time delay, which decreases the auxiliary entanglement resource required for unambiguous discrimination of hyperentangled Bell state. Therefore, this scheme provides a new way for distinguishing hyperentangled states with current technology, which will extend the application of discrimination of hyperentangled states via linear optics to other quantum information protocols besides hyperdense coding schemes in the future.