Interaction between Cu and different types of surface-modified nanoscale zero-valent iron during their transport in porous media

This study investigated the interaction between Cu^2 + and nano zero-valent iron (NZVI) coated with three types of stabilizers (i.e., polyacrylic acid [PAA], Tween-20 and starch) by examining the Cu^2 + uptake, colloidal stability and mobility of surface-modified NZVI (SM-NZVI) in the presence of Cu^2 +. The uptake of Cu^2 + by SM-NZVI and the colloidal stability of the Cu-bearing SM-NZVI were examined in batch tests. The results showed that NZVI coated with different modifiers exhibited different affinities for Cu^2 +, which resulted in varying colloidal stability of different SM-NZVI in the presence of Cu^2 +. The presence of Cu^2 + exerted a slight influence on the aggregation and settling of NZVI modified with PAA or Tween-20. However, the presence of Cu^2 + caused significant aggregation and sedimentation of starch-modified NZVI, which is due to Cu^2 + complexation with the starch molecules coated on the surface of the particles. Column experiments were conducted to investigate the co-transport of Cu^2 + in association with SM-NZVI in water-saturated quartz sand. It was presumed that a physical straining mechanism accounted for the retention of Cu-bearing SM-NZVI in the porous media. Moreover, the enhanced aggregation of SM-NZVI in the presence of Cu^2 + may be contributing to this straining effect.     

Genome-wide identification and hormone expression patterns of the MaPIF family of banana genes北大核心CSCD

植物光敏色素作用因子(phytochrome interacting factor,PIF)是广泛分布于植物体内的一种转录因子,在植物的生长发育方面有着重要的作用.基于香蕉基因组数据,对香蕉MaPIF基因家族进行基因组鉴定,采用生物信息学分析方法对其进行命名,分析理化性质、蛋白质结构、基因结构、启动子顺势作用元件以及构建系统进化树;分析PIF家族在不同激素处理下的表达情况.结果显示,香蕉MaPIF家族有7个成员,均含有高度保守的bHLH结构域;编码区长度在1 116-2001bp之间,至少包含5个内含子,且大部分位于细胞外;进化树结果可以发现与拟南芥、水稻以及玉米PIF的亲缘关系较近;顺式作用元件预测结果显示,MaPIF上存在多种与激素和光相关的响应元件.qRT-PCR结果显示,MaPIF3-1、MaPIF4、MaPIF4-1在生长素(IAA)、赤霉素(GA)、生长素抑制剂(NPA)处理中均有显著表达,除此之外,所有成员在脱落酸(ABA)处理下均有明显表达.本研究表明MaPIF在香蕉生长发育中激素调控有重要作用.(图7表3参45)     

Biomass ash pyrolyzed from municipal sludge and its adsorption performance toward tetracycline: effect of pyrolysis temperature and KOH activation

Environmental Science and Pollution Research - Large amount of municipal sludge is difficult to handle; its resource utilization is an effective measure. In this study, the municipal sludge from...     

An Enzymatic Method for Harvesting Functional Melanosomes after Keratin Extraction: Maximizing Resource Recovery from Human Hair

Journal of Polymers and the Environment - Hair contains about 80% keratins and 1–3% melanin packaged in melanosomes. Both of these are high-value and functional raw materials that have...     

Expression and regulation of the shikimic acid pathway gene DHD/SDH in tea plant (Camellia sinensis)北大核心CSCD

3-Dehydroquinic acid dehydrase/shikimate dehydrogenase (DHD/SDH) is the only bifunctional enzyme in the shikimic acid pathway. It can catalyze the generation of shikimic acid and gallic acid. To investigate the expression and regulation patterns of DHD/SDH in tea, we aimed to determine (1) the miRNA-mediated cleavage of DHD/SDH involved in the shikimic acid pathway, (2) the expression pattern of miRNA and their targets, and (3) the expression pattern of three DHD/SDH genes in tea plant (Camellia sinensis) with different hormone treatments via online prediction, RLM-RACE, and qPCR. Based on the miRNAs obtained, we identified four miRNAs that regulated CsDHD/SDH in tea. CsDHD/SDH2 was targeted by miR5180b, miR1510b-5p, and miR24; CsDHD/SDH3 was targeted by miR868-5p. We also found that CsDHD/SDH2 and CsDHD/SDH3 have a similar expression pattern under different hormone treatments, and they were synergistic with each other. CsDHD/SDH1 exhibited an expression pattern opposite to that of the other two homologues, and increased expression of CsDHD/SDH1 reduced the expression of the other two genes. © 2018 Science Press. All rights reserved.     

Removal of humic substances from landfill leachate by Fenton oxidation and coagulation

In this study, chemical oxygen demand (COD) was characterized as total organic constituents and the isolated humic substances (HS) were characterized as an individual organic contaminant in landfill leachate. It was found that the HS content of landfill leachate was 83.3%. The results of laboratory tests to determine the roles of HS in reducing the organic content of landfill leachate during Fenton process are presented. Furthermore, the performances of oxidation and coagulation of Fenton reaction on the removal of HS and COD from leachate were investigated. The change curves of HS removal were similar to those of COD. The HS removal was 30% higher than COD removal, which indicated that HS were mostly degraded into various intermediate organic compounds but not mineralized by Fenton reagent. The oxidation removal was greatly influenced by initial pH relative to the coagulation removal. The oxidation and coagulation removals were linear dependent with hydrogen peroxide and ferrous dosages, respectively. Ferrous dosage greatly influenced the coagulation removal of COD at low ratio ([H₂O₂]/[Fe²⁺] < 3.0), but not at extremely high ratio ([H₂O₂]/[Fe²⁺] > 6.0). The coagulation removal of HS was not affected obviously by oxidation due to both Fenton oxidation and coagulation remove high molecular weight organics preferentially. Higher temperature gave a positive effect on oxidation removal at low Fe²⁺ dosage, but this effect was not obvious at high Fe²⁺ dosage.     

长江2006年汛期特枯径流分析

2006年汛期长江出现了历史罕见的特枯径流,汛期长江寸滩站、嘉陵江北碚站出现了有记录以来历史同期最低水位,乌江武隆站出现了历史同期第4低水位。这一现象引起了各方面的关注。论文根据2006年长江干支流主要水文站实测数据以及长江流域33个气象站气温数据和降水量数据,对2006年汛期长江流域特枯径流进行了分析。研究发现,宜昌、汉口、大通三站的汛期月平均流量均降至有历史记录以来的最小值,部分月份不足正常年份的1/3,总体径流量偏少30%～60%。全线水位快速退落,重庆、宜昌、沙市、汉口水位为100多年来同期最低,几近常年长江枯水季节水位。研究认为降水减少是造成长江2006年汛期枯水的主要原因。2006年气温较多年平均明显偏高0.5～2℃,副高和大陆高压的异常,使汛期长江流域降水量大大减少,尤其在7～10月份,几大支流流域降水量减少幅度达到20%~80%。在全球气候变暖的背景下,对2006年汛期长江流域特枯径流进行研究具有非常重要的理论和现实意义。     

化学氧化法脱除石油焦中的硫

分别采用硝酸、硝酸-冰醋酸混合液以及王水作氧化剂脱除石油焦中的硫。实验结果表明:石油焦粒径越小,脱硫率越高;随液固比(氧化剂体积与石油焦质量比,mL/g)增大、反应时间延长、反应温度升高,脱硫率先增大,达到极值后保持稳定。王水的脱硫率高于硝酸和硝酸-冰醋酸混合液。王水脱除石油焦中硫的最佳工艺条件为:石油焦粒径0.1mm,液固比20mL/g,反应时间20h,反应温度50℃。在此最佳条件下,脱硫率达42.3%。经王水在最佳脱硫工艺条件下处理后,可有效脱除石油焦中大部分的噻吩类和硫醇类有机硫以及全部的无机硫。     

中国海滨旅游地气候适宜性评价

选定我国２５个滨海城市和１２个岛屿共计３７个测站的四项指标（气温、风速、相对湿度、日照时数的多年月平均值）３０多个系列年资料，对海滨城市和近岸岛屿的气候进行了系统分析。研究发现，我国的渤海湾沿岸海滨城市和海南南部城市有长达４～６个月的度假和休疗养的气候条件，它们在季节上有着较强的互补性，相比之下，其他海滨城市适宜旅游季节不长，且分成春、秋两个时段，综合条件不太理想。