Fluorescence ratiometric pH sensor prepared from covalently immobilized porphyrin and benzothioxanthene

A fluorescence ratiometric sensor for pH determination is described in this paper. The sensor incorporated the pH-sensitive dye meso-5,10,15,20-tetra-(4-allyloxyphenyl)porphyrin (TAPP) as an indicator and a pH-insensitive dye N-(2-methacryloxyethyl)benzo[k,l]thioxanthene-3,4-dicarboximide (MBTD), a benzothioxanthene derivative, as a reference for fluorescence ratiometric measurement. To prevent leakage of the dyes, both were photocopolymerized with acrylamide, hydroxyethyl methacrylate, and triethylene glycol dimethacrylate on the silanized glass surface. The reproducibility and response time of the prepared sensor were sufficient. Most common coexisting inorganic ions and organic compounds did not interfere with pH sensing. In the acidic pH range from 1.5 to 5.0 the fluorescence intensity ratio of the two dyes varied linearly as a function of pH. The sensing membrane was found to have a lifetime of at least one month. The sensor was applied to the analysis of waste water and artificial samples.     

Hydrothermal Synthesis and Structural Characterization of a Tubular Arsenic-Vanadate: [CoII(2,2′-bpy)2]2[AsIII8VIV14O42(H2O)]·H2O

The hydrothermal reaction of VOSO₄, As₂O₃, CoC₂O₄·2H₂O and 2,2-bipy yields a novel arsenic-vanadate [Co^II(2,2-bpy)₂]₂[As^III₈V^IV ₁₄O₄₂(H₂O)]·H₂O (1), which is characterized by IR, elemental analysis, TGA, magnetic susceptibility and single crystal X-ray diffraction analysis. X-ray diffraction shows that compound 1 is the first example of tubular arsenic–vanadium cluster containing infinite {[Co(2,2-bpy)₂]₂[As₈V₁₄O₄₂(H₂O)]} chain constructed from [As₈V₁₄O₄₂(H₂O)] clusters interconnected through [Co(2,2-bpy)]²⁺ units. Crystal data: 1, orthorhombic, P 2₁2₁2₁, a=12.1401(2) Å, b=15.8722(1) Å, c=39.9533(5) Å, Z=4.Graphical Abstract: A novel polyoxoarsenicvanadate, [Co^II(2,2-bipy)₂]₂ [As^III₈V^IV ₁₄O₄₂(H₂O)]·H₂O, is depicted along with a tubular hybrid solid with a rhombic tube formed within the chain.     

Lysophosphatidic acid induces astrocyte proliferation in hippocampus slices partially through activating extracellular signal-regulated kinases

The goal of the present study is to test the hypothesis that LPA induces proliferation of astrocytes in hippocampus in vivo via phosphorylation of ERK 1/2. We first characterized the expression of GFAP, a special marker fiber protein of astrocytes, in brain slices after direct injection of LPA into hippocampus by immunohistochemistry, and found that LPA induced a remarkable proliferation of astrocytes. Then double-lablled immunofluorescence was used to detect GFAP and phosphorylation ERK 1/2 (p-ERK 1/2), LPA induced an immediate (10 min) and transient (<30 min) phosphorylation of ERK 1/2, and sequence sustained activation of ERK 1/2 was observed, which last for at least 3 weeks after injection of LPA. Reactions are inhibited by U0126, a specific pharmacological mitogen-activated protein kinase (MEK) inhibitor. Laser confocal scanning was used to study spatial relationship of p-ERK and astrocytes. Amazingly, the early (<7 days) phosphorylation of ERK 1/2 is not expressed in astrocytes but in area where neurons and/or in other cell type(s) occupied, expression of p-ERK 1/2 in astrocytes is not detected until 14 days after LPA injection and lasts for at least 3 weeks. Taken together, these data suggest that LPA play an important role in proliferation of astrocytes through phosphorylation of ERK 1/2 in hippocampus. It provides further proof for the functions of LPA in CNS injury, and may contribute to clinical therapy for relative diseases.     

Influence of post-annealing temperature on properties of ZnO:Li thin films

Li-doped ZnO thin films were prepared on glass substrates by DC reactive magnetron sputtering. The influence of post-annealing temperature on the electrical, structural, and optical properties of the films was investigated. A conversion from p-type conduction to n-type in a range of temperature was confirmed by Hall measurement. The optimal p-type conduction is achieved at the annealing temperature of 500 °C with a resistivity of 57 Ω cm, carrier concentration of 1.07 × 10¹⁷ cm⁻³ and Hall mobility of 1.03 cm² V⁻¹ s⁻¹. From the temperature-dependent PL analysis, the energy level of Li_Zn acceptor was determined to be 140 meV above the valence band.     

米非司酮的吸附伏安特性

在ＰＨ７．０Ｂｒｉｔｔｏｎ－Ｒｏｂｉｎｓｏｎ缓冲溶液中，米非司酮（Ｍｉｆｅｐｒｉｓｔｏｎｅ，ＲＵ４８６）在汞电极上有２个不可逆的线性扫描还原峰，峰电位分别为－１．２３Ｖ和－１．６８Ｖ。本文探讨了第一峰的电化学行为。     

四氟乙烯-乙烯溶液沉淀聚合

本文编制了一个简易计算机程序,测定了氟氯烷溶液沉淀聚合体系中四氟乙烯-乙烯共聚竞聚率:40℃:γC_2H_4=0.156±0.001,γC_2F_4=0.022±0.01670℃:γC_2H_4=0.197±0.001,γC_2F_4=0.055±0.020在此聚合体系中,聚合温度和共聚物组成比对链的规整性都有明显影响。当乙烯在45～55mol%范围内时,共聚物的IR随组成比而变化,利用此规律可简便地测定共聚物的组成比。     

动力学分光光度法测定微量草酸的研究

本文详细讨论了草酸对锡－苯基荧光酮－溴化十六烷基三甲基铵三元络合物显色反应的催化动力学条件，建立了动力学光度法测定微量草酸的新方法，本法Ｓａｎｄｅｌｌ灵敏度为７．４ｎｇ／ｃｍ＾２，草酸浓度在０－１．０μｇ／ｍＬ范围有良好线性关系，方法可直接用于菠菜中草酸含量的测定。     

相转移催化合成增塑剂BBP和水杨醛的研究

相转移催化合成增塑剂ＢＢＰ和水杨醛的研究郭锡坤，高文华，曾东宇（汕头大学化学系，汕头５１５０６３）关键词相转移催化，季铵盐，聚乙二醇，邻苯二甲酸丁苄酯，水杨醛，增塑剂邻苯二甲酸丁苄酯（增塑剂ＢＢＰ）是一种优良的增塑剂．邻羟基苯甲醛（水杨醛）不仅是重要...     

电化学合成聚苯胺粉末电极的电化学行为研究

我们曾用慢速动电位扫描法研究化学合成聚苯胺粉末的电化学行为.本文对恒电位电解合成聚苯胺粉末进行了研究.用这种方法制备的粉末由于合成溶液中不含氧化剂因而纯度高.本文还报导了这种聚苯胺粉末电极的交流阻抗测量结果.交流阻抗法曾用于聚苯胺膜的电导和化学合成聚吡咯的电阻测定. 所用盐酸、氟硼酸、硅氟酸、苯胺均为分析纯;苯胺经常压蒸馏提纯;硫酸为超纯;磷酸为分析纯;高氯酸为优级纯.溶液皆用两次蒸馏水配制.     

低头-头链含量的聚偏氟乙烯合成

研究了偏氟乙烯的聚合条件与其聚合物的头-头链含量的关系。实验表明聚合物的头-头链的含量与聚合温度有关,而与引发剂的种类无关。因而,可以在较低的聚合温度下聚合制得带有低的头-头结构(约3％)的聚偏氟乙烯。将聚合物链的A结构含量对其熔点作图,得一直线,可表示为方程式A=24.8+0.362T_m(％)。