农药在水介质中的光化学降解研究情况

农药在水环境中会受到理化因子作用发生降解。本文通过对国内外关于水介质中农药光降解机理和影响因素的研究成果加以总结和归纳,阐述水介质中农药光降解的动力学模型、光化学反应类型,以及在水环境中影响农药光降解的主要因素,概述水介质中农药的光降解特性。     

Evaluation of aqueous Moringa seed extract as a seed treatment biofungicide for groundnuts

In a search for alternatives to currently used fungicides, the potential of aqueous Moringa seed extract (AMSE) as a seed treatment was evaluated. Seeds of groundnut, Arachis hypogea L cv Dakar, were soaked in AMSE at concentrations of 1, 5, 10, 15 and 20 g litre(-1) for 24 h. Comparison was made with Apron Plus (metalaxyl+carboxin+furathiocarb), until recently a recommended seed-treatment chemical, and distilled water, which was the medium for extraction of Moringa seeds. The results showed that AMSE has potential for use as a biofungicide on groundnut seeds, since all the concentrations used except 1 g litre(-1) brought about significant reduction in the incidence of fungi on the seeds, such reduction increasing as the dosage of AMSE increased. There were no significant differences in control between the highest concentration of AMSE (20 g litre(-1)) and Apron Plus at the manufacturer's recommended level. Water also produced slight reductions in the incidence of fungi, although this was not significant at P = 0.05. The sensitivity to AMSE of the fungi tested varied, Mucor sp being the most sensitive and Aspergillus niger the least, with Rhizopus stolonifer and Aspergillus flavus intermediate.     

施用10％草甘膦水剂对土壤环境的影响

本文通过三地田间试验,研究了长期施用草甘膦水剂对土壤性质的影响。结果表明,湖北罗田、潜江和广水三地土壤的电导率、钠碱化度、钠吸附比、pH值和总碱度均呈现增加的现象,虽然根据国内对盐碱土的分类标准指标三地均属于非盐化和碱化土,但有盐化和碱化的趋势。     

箭叶橐吾水溶物对9种牧草种子化感作用研究

研究了青藏高原东部草原毒杂草箭叶橐吾根、叶水溶物对9种牧草(包括与箭叶橐吾同域分布的中华羊茅、大雀麦、垂穗披碱草、早熟禾、羊茅、扁穗冰草、无芒雀麦和异域分布的牧草鸭茅、岷山猫尾草)种子萌发的化感作用。结果表明,水溶物浓度在0.2 g/mL时对垂穗披碱草等7种牧草的萌发率和萌发指数有明显抑制作用,浓度降低,其抑制作用减弱;供体不同部位水溶物的化感效应不同,根的抑制作用大于叶;水溶物对萌发指数的影响大于对萌发率的影响。综合分析箭叶橐吾水溶物对受试牧草化感作用的整体影响显示,9种牧草中,大雀麦、早熟禾和垂穗披碱草受抑制作用明显,对岷山猫尾草作用微弱,而对扁穗冰草和无芒雀麦的种子萌发有一定的促进作用;不同分布区的牧草对箭叶橐吾化感作用的反应无一致性改变。结果显示水雾淋溶是箭叶橐吾化感物质释放的途径之一,化感作用能在箭叶橐吾入侵高寒草场过程及单优势种形成中起一定作用;在人工草场恢复时,应优先选择如岷山猫尾草、扁穗冰草和无芒雀麦等对箭叶橐吾化感作用不敏感的牧草种类。     

圆柏叶片水提液对4种草坪草种子萌发和幼苗生长的影响

采用TP法研究了不同浓度的圆柏叶片水提液对多年生黑麦草、草地早熟禾、高羊茅和白三叶种子萌发和幼苗生长的影响。结果显示,圆柏水提液对4种草坪草种子萌发和幼苗生长均有抑制作用,其中,对多年生黑麦草发芽率和白三叶幼苗根长的影响不显著。圆柏叶片水提液对多年生黑麦草、草地早熟禾、高羊茅和白三叶种子萌发和幼苗生长的化感作用强度与浓度有关,浓度越高抑制作用越强,随着浓度的降低,抑制作用逐渐减弱。     

基于表面处理的麦秸人造板力学性能研究

采用碱溶液对麦秸原料进行处理,以期改善其表面润湿性,提高与胶黏剂的结合强度。基于扩散-渗透理论,对碱溶液的处理效果进行了评价,并用处理过的麦秸压制刨花板。检测结果表明:与未处理麦秸刨花板相比,处理后板材的静曲强度、弹性模量略有下降,但内结合强度提高,吸水厚度膨胀率降低,各项指标均达到相关国家标准要求。     

Evaluation of Aqueous Biphasic Electrophoresis System Based on Halide-Free Ionic Liquids for Direct Recovery of Keratinase

Aqueous biphasic electrophoresis system (ABES) incorporates electric fields into the biphasic system to separate the target biomolecules from crude feedstock. Ionic liquid (IL) is regarded as an excellent candidate as the phase-forming components for ABES because of the great electrical conductivity, which can promote the electromigration of biomolecules in ABES, and thereby enhances the separation efficiency of the target biomolecules from crude feedstock. The application of electric fields to the conventional biphasic system expedites the phase settling time of the biphasic system, which eases the subsequent scaling-up steps and reduces the overall processing time of the recovery process. Alkyl sulphate-based IL is a green and economical halide-free surfactant when compared to the other halide-containing IL. The feasibility of halide-free IL-based ABES to recover Kytococcus sedentarius TWHK01 keratinase was studied. Optimum partition coefficient (K_e = 7.53 ± 0.35) and yield (Y_T = 80.36% ± 0.71) were recorded with IL-ABES comprised of 15.0% (w/w) [EMIM][ESO₄], 20.0% (w/w) sodium carbonate and 15% (w/w) crude feedstock. Selectivity (S) of 5.75 ± 0.27 was obtained with the IL-ABES operated at operation time of 5 min with 10 V voltage supplied. Halide-free IL is proven to be a potential phase-forming component of IL-ABES for large-scale recovery of keratinase.     

主成分分析法在城市河流水质评价中的应用

采用多元统计主成分分析方法对城市河流,即伊犁河8个监测断面的高锰酸盐指数、化学需氧量、生物需氧量、溶解氧等13个水质指标进行分析计算。结果表明:从原始数据中提取占总方差88.277%的3个因子来反映水体的污染程度,经分析识别出影响伊犁河的3个主成分因子:①以氮盐、化学需氧量、生物需氧量和溶解氧等有机污染因子控制;②悬浮物和酸碱性控制;③石油类、氨氮和生物需氧量控制。主成分分析方法能真实、准确分析出城市河流各水质指标的内在关系。     

地锦草水提物在IPEC-J2细胞中的抗炎与抗氧化作用

【目的】为了揭示地锦草(EH)在猪小肠上皮细胞(IPEC-J2)中的抗炎和抗氧化作用。【方法】利用不同浓度EH水提物(0、5、10、50、125、200μg/mL)处理IPEC-J2细胞12 h,通过CCK-8法检测IPEC-J2细胞活力,确定EH处理细胞的最佳浓度。将IPEC-J2细胞随机分为对照组(CT)、脂多糖(LPS)组(LPS)、EH+LPS组(ELP),每组3个重复。CT组细胞正常培养不做任何处理,LPS组细胞用5μg/mL LPS处理,ELP组细胞用5μg/mL LPS和最佳浓度EH共处理,各组细胞均处理12 h后,收集细胞和上清。利用实时荧光定量PCR方法检测细胞中白细胞介素-6(IL-6)、肿瘤坏死因子α(TNF-α)、kelch样环氧氯丙烷相关蛋白1(Keap1)、核因子E2相关因子(Nrf2)、血红素加氧酶1(HO-1)mRNA表达;ELISA法检测上清液中丙二醛(MDA)、超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)的含量,化学荧光法检测上清液中活性氧(ROS)水平。【结果】与0μg/mL EH组相比,5、50μg/mL EH组IPEC-J2细胞...     

酶法有限水解含油菜籽蛋白的机理及动力学

为探索油菜籽水相酶解法萃取菜籽油的机理,以Alcalase蛋白酶在温度50℃、pH8.0条件下,对以水剂法从菜籽中提取的含油菜籽蛋白进行酶解处理.试验研究结果表明:含油菜籽蛋白乳液的固形物颗粒度对酶解反应速率有明显影响,总的趋势是颗粒度越小,酶促反应速率越大;酶催化水解速率随水解进程呈指数下降,在反应过程中过高的底物浓度会抑制酶的失活.在此基础上由试验数据推导出描述催化水解含油菜籽蛋白的动力学方程,由此通过控制酶与底物浓度之比、反应时间,可以控制水解作用的程度,从而指导和优化菜籽水相酶解法提取菜籽油的工艺.