海藻酸钠固定化纳米铁还原脱色活性红X3B

采用海藻酸钠固定纳米铁制备海藻酸钠纳米铁小球,研究了海藻酸钠浓度、纳米铁含量、活性红X3B浓度、反应温度、pH值等对海藻酸钠固定化纳米铁小球还原活性红X3B的影响.采用高效液相色谱（HPLC）、紫外可见分光光度计（UV-Vis）、扫描电镜（SEM）、透射电镜（TEM）等方法分析污染物的还原脱色过程.结果表明,X3B的还原脱色获得了较好的效果,当温度25.0℃,海藻酸钠浓度2.0%,纳米铁含量2.0g/L,转速200r/min,pH值10.9时,反应720min后,25.0mg/L活性红X3B的脱色率达98.9%.海藻酸钠凝胶对活性红X3B没有吸附作用,海藻酸钠固定化纳米铁小球降解活性红X3B的主要机制为纳米零价铁的还原作用.     

增塑剂邻苯二甲酸二异壬酯致小鼠肺细胞氧化损伤作用的研究

为研究增塑剂邻苯二甲酸二异壬酯(diisononyl phthalate,DINP)对小鼠肺组织的氧化损伤作用,以昆明小鼠为受试动物,随机分为5组,包括1个阴性对照组(生理盐水)和4个DINP染毒组(0.2、2、20和200 mg·kg~(-1)),灌胃14 d。光镜下发现小鼠肺组织形态随染毒剂量的增加,小鼠肺细胞的病理损伤越严重。随着DINP染毒剂量的增加,肺组织匀浆活性氧(reactive oxygen species,ROS)、丙二醛(malondialdehyde,MDA)含量和肺组织细胞DNA-蛋白质交联(DNA-protein crosslink,DPC)系数逐渐上升,还原型谷胱甘肽(glutathione,GSH)含量逐渐降低,各指标呈一定的剂量-效应关系。染毒剂量为20 mg·kg~(-1)时,ROS和MDA含量差异有统计学意义(P0.05,P0.01);染毒剂量为200 mg·kg~(-1)时,上述指标差异均有统计学意义(P0.01)。结果表明,较高剂量(≥20 mg·kg~(-1))的DINP能造成小鼠肺组织的氧化损伤和病理损伤。     

Toxicity of cadmium nanoparticles to Bacillus subtilis

The study deals with the toxicological impact of cadmium nanoparticles (Cd NPs) on Bacillus subtilis as a model Gram-positive bacterium. Cadmium oxide (CdO) NPs (～22 nm) and cadmium sulfide (CdS) NPs (～3 nm) were used in this study. Both the NPs were found to inhibit the cell viability of B. subtilis when added to the culture at mid-log phase, the viable cell number declined with increasing concentration of Cd NPs. At mid-log phase, 15 mg L^?1 CdO NPs inhibited growth by ～50%, whereas at 30 mg L^?1 growth completely ceased. Under the same conditions, CdS NPs inhibited growth by ～50% at a concentration of 8 mg L^?1, and at 20 mg L^?1 growth was completely retarded. The cells changed their morphological features to a filamentous form with increasing Cd NPs exposure time, leading to associated with clumping. NPs treated cells when stained with 4′, 6-diamino-2-phenylindole, showed filamentous multinucleated bead structure, suggesting irregularities in cell division. Increasing intracellular oxidative stress due to Cd NPs exposure might be one of the reasons for the cell morphological changes and toxicity in B. subtilis.     

Ethyl mercury induces Ca2+ uptake through the P2×7 receptor in a mouse cerebellar microglia cell line

Many observations are reported that organic mercury compounds are involved in increasing intracellular Ca²⁺ levels. However, the issue of which substances on the cell membrane participate in the Ca²⁺ uptake that is induced by ethyl mercury is unclear. The findings of this study suggest that the P2X receptor participates in this process. The uptake of Ca²⁺ by C8-B4 cells was induced in the presence of ethyl mercury. Ca channels in the cell membrane were not affected in this process. In contrast, pretreatment with suramin, an antagonist of the P2X receptor, inhibited the Ca²⁺ uptake induced by ethyl mercury, and also brilliant blue G, a nonselective antagonist of P2×4, P2×5, and P2×7 receptors. In addition, A438079 and A740003, selective antagonists of P2×7 receptor, reduced Ca²⁺ uptake, while 5-BDBD, a selective antagonist of P2×4 receptor, did not. Furthermore, the mRNAs of both the P2×4 and P2×7 receptors were expressed in the presence of ethyl mercury, but the P2×5 receptor mRNA was not. These findings suggest that ethyl mercury may induce Ca²⁺ uptake through the P2×7 receptor of the cell membrane.     

Iron-doped copper 1,4-benzenedicarboxylate as photo-Fenton catalyst for degradation of methylene blue

Abstract

A metal-organic framework of iron-doped copper 1,4-benzenedicarboxylate was synthesized and, for the first time, utilized as a heterogeneous photo-Fenton catalyst for degradation of methylene blue dye in aqueous solution under visible light irradiation. The synthesized materials were characterized by scanning electron microscopy, Fourier-transform infrared spectroscopy, X-ray diffraction and energy-dispersive X-ray spectroscopy. The influence factors, kinetics, and stability of the synthesized catalysts were investigated in detail. Iron-doped copper 1,4-benzenedicarboxylate showed higher degradation efficiency than pure copper 1,4-benzenedicarboxylate. An almost complete degradation was achieved within 70?min under visible light irradiation at a solution pH of 6, a catalyst loading of 1?g?L^?1, a H₂O₂ dosage of 0.05?mol L^?1 and methylene blue concentration of 50?mg?L^?1. Recycling studies demonstrated that the iron-doped copper 1,4-benzenedicarboxylate is a promising heterogeneous photo-Fenton catalyst for long-term removal of methylene blue dye from industrial wastewater.     

Modeling and optimization of Nile blue sulfate mineralization by heterogeneous fenton oxidation

Artificial neural network and response surface methodology have been used to develop a model for simulation and optimization of the removal of Nile blue sulfate by heterogeneous Fenton oxidation. Experimental data were used to train an artificial neural network model with linear transfer function at the output layer and a tangent sigmoid transfer function at the hidden layer. A Box–Behnken design was employed to assess the effects of input process parameters on the total organic carbon removal. First order kinetics and lumped kinetics models were used to describe the reaction; a high regression coefficient indicated that the latter fitted best. The formation of non-oxidizable compounds was shown by liquid chromatography–mass spectrometry.     

Electrophoretic and liquid chromatographic characterization of red cell membrane proteins modified by chromate

Besides its effects of the genetic material and function, chromate also immediately affects the structure and function of cell membranes. With human erythrocytes, chromate produces alterations in cell size and shape, it impairs the anion transport function, and it causes modifications in membrane constituents. The proteins have been analysed by one‐ and two‐dimensional gel electrophoresis and by fast protein liquid chromatography (FPLC). The main chromate effects are the crosslinking of proteins including the membrane protein bands 1 and 2 (spectrin) and haemoglobin. Furthermore, a 40.000 D membrane protein fraction is modified. Chromate may react directly with membrane constituents but evidence also points to the formation of reactive oxygen compounds which in turn may react with proteins and lipids of the cell membrane.     

Acute nitrate poisoning in two cattle

Abstract

The rate and product composition during photooxidation of aromatic hydrocarbons (toluene, o‐, m‐, p‐xylene and cumene) dissolved in n‐hexane and spread as a liquid film on water is reported. The photo degradability of these chemicals is 10–20%. The products identified are oxygenated aromatic compounds. It is observed that the absorption bands of the compounds under investigation depend upon the partial pressure of dissolved oxygen and these bands extend up to 290 nm. The new absorption band around 290 nm is probably due to broadening of ¹L_b bands which is responsible for direct photolysis.

stream. We have been especially interested in investigating the rate of disappearance and distribution of main oxidation products in two phases. Besides that an attempt has been made to throw some light on the reaction mechanism.     

Adsorption of methylene blue from aqueous solution by chemically treated water hyacinth

Water hyacinth (WH), an aquatic plant macrophyte, was investigated for its ability to perform as a suitable adsorbent for methylene blue (MB) from aqueous solution. The non-living biomass of WH was subjected to several chemical treatments, namely, washing with hot water, washing with hot dilute HCl, soaking in NaOH, soaking in HNO₃, and sulfonation. The system variables studied also include pH and MB concentration. The Langmuir isotherm was found to represent the measured adsorption data well except for WH soaked in NaOH, which was found to be better represented by the Freundlich isotherm. Values of the dimensionless separation factor, K _R, indicated that the adsorption systems in this study are all favorable. Values of the first layer of adsorption were calculated by the non-linear multilayer adsorption model, and the specific surface area values were found to be high and comparable to commercially activated carbons.     

离子液体对有机染料的萃取行为

以疏水性离子液体1-甲基-3-丁基咪唑六氟磷酸盐([bmim]PF6)为萃取剂,液-液体系中对6种常见有机染料结晶紫、孔雀绿、罗丹明B、亚甲基蓝、铬天青S以及偶氮氯膦Ⅲ的萃取行为进行了研究,考察了溶液pH、萃取时间、离子液体浓度以及盐的含量对萃取率的影响.结果表明,离子液体对水中不同结构染料的萃取能力有很大差异:在pH 3—9的条件下,离子液体对结晶紫和亚甲基蓝的萃取能力很强,萃取率均在90%以上;在pH值3—5的条件下,对孔雀绿的萃取率在86%以上;在pH值为3的条件下,对罗丹明B的萃取率为94%,且酸度减小时萃取率下降;在pH 7—11时对铬天青S和偶氮氯膦Ⅲ的萃取率分别小于36%和29%,且酸度增大时萃取率下降.对各种染料均可在5—10 min内完成萃取,萃取后分相迅速,相界面清晰,无浑浊或第三相形成,有着传统有机溶剂无法比拟的优点.本研究对采用离子液体萃取净化染料废水和回收废弃燃料具有一定的参考价值.