Structural alterations in compound eye of Drosophila melanogaster in response to sodium fluoride treatment

Sodium fluoride, used as a pesticide in agriculture, is also an ingredient of toothpastes which help to fight dental problems. In this study, Drosophila melanogaster, a non-target organism, is used to explore morphological changes in the adult compound eye as a function of exposure to fluoride at 20, 40, 80, 100 and 150 mg L^?1, using scanning electron microscopy. The experimental concentrations were much lower than the ones used in the studies of the British Association of Community Dentistry. Distinct morphological alterations in the eye of the treated insects revealed ommatidial ridges and disoriented mechanosensory bristles which were most prominent in the 40 and 80 mg L^?1 treatment groups. Since humans and Drosophila share homology in many genes that are involved in developmental pathways, the present findings raise concern on the use of sodium fluoride as a pesticide.     

过硫酸钠对砂壤土中三氯乙烯的氧化研究

以过硫酸钠(Na2S2O8)为氧化剂,柠檬酸(CA)螯合Fe(Ⅱ)溶液作为活化剂,对砂壤土中的三氯乙烯(TCE)进行处理.采用正交试验获得优化操作条件为: Na2S2O8浓度5mmol/L,Fe(Ⅱ)浓度2.5mmol/L,CA浓度0.25mmol/L,反应时间30min.在此条件下,土壤中不同浓度的TCE去除率均在93%以上.对于污染程度高的土壤,采用连续氧化处理可达到较高的修复目标要求.土柱实验结果表明经过Na2S2O8溶液氧化7d后,TCE氧化率达到88.9%以上,且去除效果与处理方式有关,分次加入方式的效果最好.     

聚丙烯酸钠-硅溶胶的合成及其对阳离子金黄染料的吸附

通过简单的水溶液聚合法成功合成了聚丙烯酸钠-硅溶胶复合吸附剂,并对其进行了SEM和热重分析,研究了吸附条件对该吸附剂对阳离子金黄染料吸附效果的影响。实验结果表明,当硅溶胶质量分数为20%、初始染料质量浓度为60 mg/L、初始溶液pH为7、反应温度为298 K时,聚丙烯酸钠-硅溶胶复合吸附剂对阳离子金黄染料的吸附量为64.64 mg/g。由二级吸附动力学模型获得的活化能(Ea=2.617 kJ/mol)表明,聚丙烯酸钠-硅溶胶复合材料对阳离子金黄的吸附属于物理吸附,低温有利于吸附。     

AN ASSESSMENT OF SEDIMENT PHOSPHORUS INACTWATION,KEZAR LAKE,NEW HAMPSHIRE1

ABSTRACT: Aluminum sulfate and sodium aluminate were utilized as sediment phosphorus inactivants to improve the water quality of a northeastern eutrophic lake. A four-year monitoring program has provided an extensive lake-database utilized to evaluate the short-and long-term effectiveness of sediment phosphorus inactivation as a lake restoration technique. An immediate impact of treatment was marked by a reduction in hypolimnetic BOD and dissolved oxygen deficit, lower chlorophyll-a and phosphorus concentrations, improved transparency, and the elimination of obnoxious blue-green phyto-plankton blooms. For two to three years after treatment, these pa-rameters continued to exhibit both less variability and improved values over the pre-treatment conditions. The improved water quality conditions warranted an upgrade of the lake trophic status from eutrophic to mesotrophic. Four years after the treatment, the mean hypolimnetic total phosphoru.s and chlorophyll-a have increased and transparency has decreased from initial post-treatment levels. Although long-term trends show water quality decreasing since the treatment, the water quality has stabilized at a level suitable for recreation. A major benefit is an increase in the average attendance at the lake by almost 2,000 people per summer.     

提高芒硝制硝酸钠产品质量的措施与方法

本文分析了芒硝复分解法制硝酸钠产品质量较差的主要原因，探索了解决方法，并确定出最佳工艺条件、试验产品质量达到国标标准．对开发芒硝资源的新用途具有实际意义。     

培育优势菌种处理腈纶厂硫氰酸钠废水

采用两段生物氧化法处理腈纶厂的硫氰酸钠废水，Ⅰ段去除易降解的有机物，Ⅱ段培育以自养性排硫杆菌为主体的生物膜，降解硫氰酸钠。试验装置的容积负荷达１．１—２．２ｋｇＮａＳＣＮ／ｍ￣３·ｄ，比单级氧化池处理同类废水试验的容积负荷提高２—４倍。文中介绍了试验装置运转情况，两段生物膜的特性，探讨了在第Ⅱ段氧化池中硫氰酸钠生物降解的动力学模型。     

Sodium Persulfate Oxidation for the Remediation of Chlorinated Solvents (USEPA Superfund Innovative Technology Evaluation Program)

This study has been conducted at the University of Connecticut (UCONN) in connection with the USEPA Superfund Innovative Technology Evaluation (SITE) program to evaluate a chemical oxidation technology (sodium persulfate) developed at UCONN. A protocol to assess the efficacy of oxidation technologies has been used. This protocol, which consists of obtaining data from a treatability study, tested two in-situ chemical oxidation technologies that can be used on soil and groundwater at a site in Vernon, Connecticut. Based on the treatability report results and additional field data collected at the site, the design for the field implementation of the chemical oxidation remediation was completed. The results indicate that both sodium persulfate and potassium permanganate were able to effectively degrade the target VOCs (i.e., PCE, TCE and cis-DCE) in groundwater and soil-groundwater matrices. In the sodium persulfate tests (120 hrs), the extent of destruction of target VOCs was 74% for PCE, 86% for TCE and 84% for cis-DCE by Na₂S₂O₈ alone and 68% for PCE, 76% for TCE, and 69% for cis-DCE by Fe(II)-catalyzed Na₂S₂O₈. The results demonstrate the sodium persulfate's ability to degrade PCE, TCE and cis-DCE. It is expected that given sufficient dose and treatment time, a higher destruction rate of the dissolved phase contamination can be achieved. The data also indicates that the catalytic effect of the iron chelate on persulfate chemistry was much less pronounced in the soil-groundwater matrix. This indicates an interaction between the iron chelate solution and the soil, which may have resulted in a lower availability of the chelated iron for catalysis. The study showed that the remediation of the VOCs-contaminated soil and groundwater by in-situ chemical oxidation using sodium persulfate is feasible at the Roosevelt Mills site. As a result, the USEPA SITE program will evaluate this technology at this site.     

氯酸钠和亚铁氰化钾的热稳定性研究

采用同步热分析仪（STA）研究了氯酸钠、亚铁氰化钾及其混合物的热分解过程,得到了它们的热流-温度和质量-温度的变化曲线。并通过热分解动力学原理,求得了氯酸钠与亚铁氰化钾混合物的起始放热温度为259．7℃,分解反应热为502．5J／g。     

UASB反应器处理异VC钠废水的启动特性研究

在污泥接种浓度为10g／L,水温35℃-38℃的条件下,采用逐渐加大进水量提高有机负荷的方式45d内可以完成UASB反应器处理异VC钠生产废水的启动。启动完成后UASB反应器的容积负荷为6kgCOD／（m^3·d）,CODcr去除率可以达到85％。调试过程中向反应器内加入适量FeSO4,可以使污泥在较短时间内实现颗粒化,形成粒径为1mm～2mm、沉降性能良好的颗粒污泥。反应器出水VFA保持在400mg／L以下并能比pH更灵敏的反应出反应器内部的环境变化。     

焦亚硫酸钠对大鼠背根节神经元L-型钙电流的影响

为了探讨二氧化硫(SO2)及其衍生物对背根节神经元的生理调节作用,应用全细胞膜片钳技术,研究了SO2衍生物焦亚硫酸钠(sodiummetabisulfite,SMB)对大鼠背根节神经元L-型钙电流(ICa,L)的影响.结果表明,SMB可增大ICa,L,且具有剂量依赖性和电压依赖性的特征.SMB可使ICa,L的激活和失活过程均向去极化方向移动,但对失活的影响要大于对激活的影响,从而可导致背根节神经元钙离子内流增大,引起细胞内钙离子浓度增加.这说明SO2及其衍生物对背根节神经元的生理功能有调节作用,当其浓度过高时也可能引起该神经元的病理生理改变.