Electric-field response of discotic hexabenzocoronene (HBC) liquid crystals

A HBC derivative bearing six branched, space-demanding, alkyl side chains containing ether linkages has been synthesized and its thermotropic properties were investigated by polarization optical microscopy (POM) and differential scanning calorimetry (DSC). To our surprise, this molecule can respond to electric fields, and the influences of alternating current (AC) and directing current (DC) electric field on the assembly of this molecule in liquid crystal cells were discussed.     

Studies on the interaction of achiral cationic pseudoisocyanine with chiral metal complexes

The effect of chiral metal complexes ([Co(en)(3)]I(3)·H(2)O, cis-[CoBr(NH(3))(en)(2)]Br(2), K[Co(edta)]·2H(2)O and [Ru(phen)(3)](PF(6))(2)) on the polymer-bound J-aggregates in aqueous mixtures of pesudoisocyanine (PIC) iodine and poly(acrylic acid, sodium)(PAAS) have been studied by UV-vis absorption, circular dichroism (CD) and fluorescence spectra. At low concentration, the PIC monomers could self-assemble to form supermolecules by binding to each of the COO(-) groups on the polymer chains through electrostatic interactions. After the addition of chiral metal complexes to the formed PIC-PAAS J-aggregates, we found that only the chiral multiple π-conjugated phenanthroline metal complexes could transfer their metal-centered chiral information to the formed J-aggregates. The chiral J-aggregates showed a characteristic induced circular dichroism (ICD) in the visible region of J-band chromophore, and the ICD signals depend on the absolute configuration, concentration of the chiral multiple π-conjugated metal complexes, as well as temperature. More interestingly, the supramolecular chirality of the polymer supported PIC J-aggregates could be memorized even after the addition of an excess opposite chiral complex enantiomers. This is in sharp contrast to the behavior in the high concentrated NaCl induced PIC-J aggregates, in which the optical rotation of a mixture of two enantiomers varies linearly with their ratio.     

Silver nanoprobe for sensitive and selective colorimetric detection of dopamine via robust Ag-catechol interaction

Dopamine exhibits intriguing reactivity with silver nanoparticles through Ag-catechol interaction, which results in non-crosslinking AgNP aggregation, thus providing a novel approach for colorimetric detection of dopamine with high sensitivity and selectivity.     

Modulating DNA-templated silver nanoclusters for fluorescence turn-on detection of thiol compounds

Based on the fact that the fluorescence response pattern of a silver nanocluster to a specific analyte is highly dependent on the nature of the DNA template, we develop a novel fluorescence turn-on assay for thiol compounds with high specificity and sensitivity by modulating DNA-templated silver nanoclusters.     

A facile synthesis of anatase TiO2 nanosheets-based hierarchical spheres with over 90% {001} facets for dye-sensitized solar cells

Anatase TiO(2) nanosheets-based hierarchical spheres with over 90% {001} facets synthesized via a diethylene glycol-solvothermal route were used as photoanodes of dye-sensitized solar cells, which generated an energy conversion efficiency of 7.51%.     

Dissolution properties of oxymatrine in citric acid solution

In this article, the enthalpy of dissolution for oxymatrine in 0.15 M citric acid solution is measured using a RD496-2000 Calvet Microcalorimeter at 36.5 °C under atmospheric pressure. The differential enthalpy (Δ _dif H _m) and molar enthalpy (Δ _sol H _m) were determined for oxymatrine dissolution in 0.15 M citric acid solution. On the basis of these experimental data and calculated results, the kinetic equation, half-life, Δ _sol H _m, Δ _sol G _m, and Δ _sol S _m of the dissolution process were also obtained.     

pH-switchable inversion of the metal-centered chirality of metallabenzenes: opposite stereodynamics in reactions of ruthenabenzene with L- and D-cysteine

We report herein the first study on the chemical interaction between metallabenzenes and bioactive molecules. Due to its unique stereoelectronic activities, a phenanthroline-derived ruthenabenzene [Ru{CHC(PPh(3))CHC(PPh(3))CH}Cl(C(12)H(8)N(2))(PPh(3))]Cl(2) (1) selectively binds cysteine in aqueous solution at physiological pH and then undergoes a dynamic inversion of configuration at the Ru center. The structure of the L-cysteine-binding product of 1 has been determined by means of X-ray diffraction. The replacement of the L-cysteine with the D form results in an inverted stereodynamic effect. Furthermore, the inversion process of the Ru-centered configuration could be conveniently controlled by a simple pH adjustment. This is attributed to the significant influence of a special intramolecular electrostatic interaction on the dynamic epimerization process of the cysteine-binding product.     

水源性病原菌光谱检测技术研究进展

水源性病原菌污染会引发多种疾病,严重危害人类健康和公共卫生安全。水源性病原菌检测对人类医疗保健、水安全保障和疾病诊断等具有重要的意义。常规水源性病原菌检测技术,如人工培养法、分子生物法和免疫学法,其测量结果准确、有效,但样品预处理繁琐且费时,不利于病原菌实时在线检测。光谱检测技术以非侵入式获取病原菌发射、散射或吸收光谱特征,能够确定病原菌性质、结构和含量等信息。由于该技术具有易于操作、快速、便携、无损和便于实时监测等优点,在环境监测、生物分析中具有广泛的应用前景。文章介绍了现有水源性病原菌检测技术及其优缺点,指出开展病原菌快速、高效检测的必要性;讨论了光谱检测技术原理及数据分析方法,重点综述了紫外可见光谱、荧光光谱、红外光谱、拉曼光谱和太赫兹光谱在水源性病原菌检测的工作原理和研究进展;最后总结了各技术的优缺点。提出了光谱技术在病原菌检测的实际应用中面临的挑战及应对策略,为进一步发展基于光谱技术的水源性病原菌的快速检测提供参考。     

A New Dual-peak Fluorescent Probe for Water Content Detection Made From Taxus

In this paper, the leaves of Taxus were used as the sole carbon source, and two kinds of carbon dots blue and red, with different properties, were synthesized by the hydrothermal method under different conditions. The red carbon dots were quenched in the water, and the blue carbon dots had stable fluorescence properties in water environment. The bimodal fluorescence probe formed by mixing could accurately and stably measure the water content in ethanol, which was in the range of 82.5%-100%, is highly correlated with the fluorescence intensity ratio (I₄₈₁/I₆₇₈) of mixed carbon dots under 390 nm excitation light, with R²?=?0.995 and the detection limit as low as 0.31%. The experimental materials are environmentally friendly, low in cost, and simple to operate, as well as the water content measured by proportional fluorescence has high accuracy, which provides a new method for measuring moisture in ethanol.