A new fluorescent quenching method for the determination of phosphoproteins by using calconcarboxylic acid

A fluorescent quenching detection method for phosphoproteins in SDS‐PAGE by using calconcarboxylic acid (CCA) was described. In this method, the fluorescence intensity of CCA was greatly increased with the presence of Al³⁺ in the gel background, while in zones where phosphoproteins are located this intensity was absent because of fluorescence quenching phenomenon through the formation of CCA‐Al³⁺‐phosphoprotein appended complex. Approximately 4–8 ng of phosphoproteins can be selectively detected within 1 h (1D SDS‐PAGE), which is similar to that of the most commonly used Pro‐Q Diamond stain. The specificity of this novel technique for phosphoproteins was confirmed by dephosphorylation, Western blot, and LC‐MS/MS analysis, respectively. Furthermore, to better understand the newly developed method, the detection mechanism of CCA stain was explored by fluorescent spectrometry. According to the results, it is believed that CCA stain may provide a new choice for selective, economical, MS compatible, and convenient visualization of gel‐separated phosphoproteins.     

Defluorination and Mineralization of Difluorophenols in Water by Anodic Contact Glow Discharge Electrolysis

Anodic contact glow discharge electrolysis (CGDE) is a DC-excited atmospheric pressure discharge, in which a steady non-thermal plasma is generated locally between the surface of an electrolytic solution and an anode in contact with it. The I–U characteristics of CGDE were investigated. The plasma temperatures were estimated to be in the range, 1373–2045 K. Hydroxyl radicals and hydrogen peroxide were the main oxidants generated by CGDE. The hydrogen peroxide concentration reached 31.2 mmol/L (mM) in a phosphate buffer solution without organic substrates. During CGDE, the DFPs and the corresponding total organic carbon (TOC) in water were consumed. Most of the fluorine atoms in the DFPs were converted to fluoride ions, and the fluoride concentration increased steadily. An analysis of the hydroxylation of DFPs suggested that the hydroxyl radicals generated by CGDE were the key species responsible for the degradation of DFPs, and the possible mechanistic routes of the mineralization of DFPs are proposed. The disappearance of DFPs and the TOC as well as the defluorination of the DFPs followed first-order kinetics. The rate of TOC disappearance was relatively constant: 1.00 ± 0.05 × 10^?2 min^?1. The order of disappearance of the DFPs was 2,6-DFP > 2,3-DFP > 2,5-DFP > 2,4-DFP > 3,4-DFP > 3,5-DFP. In contrast, the order of defluorination of the DFPs was 2,5-DFP > 2,3-DFP > 2,6-DFP > 2,4-DFP > 3,4-DFP > 3,5-DFP. Overall, the order of the reaction rates for each DFP was k_DFP > k_dF > k_TOC.     

IR spectrum and normal mode analysis of the antiAlzheimer''''s disease natural product Huperzine A: A quantum chemistry density-functional theory (DFT) investigation

ＨｕｐｅｒｚｉｎｅＡ(ＨｕｐＡ),ａｎａｌｋａｌｏｉｄｉｓｏｌａｔｅｄｆｒｏｍＣｈｉｎｅｓｅｈｅｒｂＨｕｐｅｒｚｉａｓｅｒｒａｔａＴｈｕｎｂ[1],ｉｓａｐｏｔｅｎｔｒｅｖｅｒｓｉｂｌｅａｃｅｔｙｌｃｈｏｌｉｎｅｓｔｅｒａｓｅ(ＡＣｈＥ)ｉｎｈｉｂｉｔｏｒ[2]ｗｉｔｈｈｉｇｈｅｆｆｉｃａｃｙａｎｄｌｏｗｔｏｘｉｃｉｔｙ(ｆｉｇ.1).Ａｃｅｔｙｌｃｈｏｌｉｎｅ(ＡＣｈ)ｉｓａｃｈｅｍｉｃａｌｓｕｂｓｔａｎｃｅ,ｗｈｉｃｈｃａｎｔｒａｎｓｍｉｔｔｈｅｓｉｇｎａｌｏｆｎｅｒｖｅｉｍｐｕｌｓｅ.Ｔｈｅｒｅａｒｅｍａｎｙ…     

Simultaneous measurement of temperature and strain using a long-period fiber grating with a micro-taper

An all-fiber Mach–Zehnder interferometer (MZI) consisting of a long-period fiber grating with a micro-taper is proposed for simultaneous measurement of temperature and strain. The experimental results demonstrate that the temperature and strain sensitivities of the proposed MZI are 83 pm/°C and ?2.6 pm/με, respectively. The strain sensitivity is 20 times as high as that of a long-period fiber written by CO₂ laser pulses combined with a fiber bitaper. In addition, the interferometer requires only a common single-mode fiber, and it is easy to fabricate and is inexpensive for temperature and strain sensing applications.     

金纳米粒子-壳聚糖-石墨烯纳米复合材料的制备及其在生物电化学中的应用

通过共价键作用和原位还原法制备了金纳米粒子/壳聚糖-石墨烯纳米复合材料(AuNPs/Chit-GP). 利用FT-IR, UV-vis, TEM以及XRD对所合成的纳米复合物的结构和形貌进行了表征. AuNPs/Chit-GP呈现明显的正电荷, 因此可通过静电相互作用固载葡萄糖氧化酶(GOD), 并构建GOD/AuNPs/Chit-GP/GC修饰电极. 该修饰电极不仅可成功地实现GOD与电极间的直接电子转移, 还对葡萄糖表现出良好的催化性能. 实验结果表明, 其催化的线性范围为2.1～5.7 μmol/L, 检出限为0.7 μmol/L, 灵敏度为79.71 mA·cm^-2·mM^-1. 这种集金属纳米粒子、生物相容性高分子以及石墨烯为一体的纳米复合物的构筑为无媒介体的电化学生物传感器的研究提供了一个良好的平台.     

A pH‐Neutral,Metal‐Free Aqueous Organic Redox Flow Battery Employing an Ammonium Anthraquinone Anolyte

Redox‐active anthraquinone molecules represent promising anolyte materials in aqueous organic redox flow batteries (AORFBs). However, the chemical stability issue and corrosion nature of anthraquinone‐based anolytes in reported acidic and alkaline AORFBs constitute a roadblock for their practical applications in energy storage. A feasible strategy to overcome these issues is migrating to pH‐neutral conditions and employing soluble AQDS salts. Herein, we report the 9,10‐anthraquinone‐2,7‐disulfonic diammonium salt AQDS(NH₄)₂ , as an anolyte material for pH‐neutral AORFBs with solubility of 1.9 m in water, which is more than 3 times that of the corresponding sodium salt. Paired with an NH₄I catholyte, the resulting pH‐neutral AORFB with an energy density of 12.5 Wh L^?1 displayed outstanding cycling stability over 300 cycles. Even at the pH‐neutral condition, the AQDS(NH₄)₂ /NH₄I AORFB delivered an impressive energy efficiency of 70.6 % at 60 mA cm^?2 and a high power density of 91.5 mW cm^?2 at 100 % SOC. The present AQDS(NH₄)₂ flow battery chemistry opens a new avenue to apply anthraquinone molecules in developing low‐cost and benign pH‐neutral flow batteries for scalable energy storage.     

Lead and uranium sorption characteristics on hydrothermal synthesized delta manganese dioxide

Journal of Radioanalytical and Nuclear Chemistry - In present paper, delta manganese dioxide is prepared with a hydrothermal method, and the adsorption is investigated with a batch method. The...     

IR spectrum and normal mode analysis of the antiAlzheimer’s disease natural product Huperzine A: A quantum chemistry density-functional theory (DFT) investigation

Quantum chemistry density-functional theory (DFT)B3LYP method with 6-31G basis set has been empolyed to study the electronic structure and IR spectrum of Huperzine A. The calculation result showed that the characteristic of the predicted IR bands was in general consistent with the experimental spectrum. 45 vibration modes were assigned clearly from the total of 102 vibration bands. The strongest IR-intensive band corresponds to the stretching vibration of the C=O bond of the pyridone ring, and the highest frequency band belongs to the pyridone N-H stretch. The investigation showed that the obvious differences between the calculated bands and the experimental spectrum existed at the bands involving the hydrogen atoms of amino and pyridone amide groups, which could form intermolecular hydrogen bond with other Huperzine A in the crystal structure. The hydrogen bonds can not only affect the orientation of these hydrogen atoms, but also can affect the force property of the chemical bond, which can change the vibrational frequencies. Project supported by the “863” High Technology Program of China (No. 863-103-04-01) and the National Natural Science Foundation of China (Grant No. 29403027).     

标准物质的选择及使用

介绍标准物质在哈尔滨气化厂的使用情况,解决了标准物质出现的质量问题。     

A pH‐Neutral,Metal‐Free Aqueous Organic Redox Flow Battery Employing an Ammonium Anthraquinone Anolyte

Redox‐active anthraquinone molecules represent promising anolyte materials in aqueous organic redox flow batteries (AORFBs). However, the chemical stability issue and corrosion nature of anthraquinone‐based anolytes in reported acidic and alkaline AORFBs constitute a roadblock for their practical applications in energy storage. A feasible strategy to overcome these issues is migrating to pH‐neutral conditions and employing soluble AQDS salts. Herein, we report the 9,10‐anthraquinone‐2,7‐disulfonic diammonium salt AQDS(NH₄)₂ , as an anolyte material for pH‐neutral AORFBs with solubility of 1.9 m in water, which is more than 3 times that of the corresponding sodium salt. Paired with an NH₄I catholyte, the resulting pH‐neutral AORFB with an energy density of 12.5 Wh L^?1 displayed outstanding cycling stability over 300 cycles. Even at the pH‐neutral condition, the AQDS(NH₄)₂ /NH₄I AORFB delivered an impressive energy efficiency of 70.6 % at 60 mA cm^?2 and a high power density of 91.5 mW cm^?2 at 100 % SOC. The present AQDS(NH₄)₂ flow battery chemistry opens a new avenue to apply anthraquinone molecules in developing low‐cost and benign pH‐neutral flow batteries for scalable energy storage.