Acute effects of low-dose cypermethrin on male rat cells

Effects of synthetic pyrethroid insecticide α-cypermethrin were investigated following intradermal dose (5–50 mM) of cypermethrin to male albino Wistar rats. Glucose, protein, cholesterol, triglycerides, urea, uric acid, creatinine, hemoglobin, blood RBC, and WBC content were determined 6 h after pesticide administration. Biochemical parameters and blood cell count changed significantly in treated rats at all doses. Low-dose cypermethrin affected early biochemical changes in rats.     

Hepatitis B virus infection among health care workers in Public Teaching Hospitals in Khartoum State, Sudan

Background

Hepatitis B virus (HBV) infection is a global public health problem. It is estimated that there are more than 300 million HBV carriers in the world.

Aim

The study aimed to examine the sero-prevalence of hepatitis B virus (HBV) markers among health care workers (HCWs) in Public Teaching Hospitals in Khartoum State, in the year 2004.

Methods

The study is an observational, cross sectional, facility-based study. It was conducted on stratified two-stage cluster random sample of 843 subjects. The study followed non-parametric statistical methods, using Z-test for single proportion.

Results

Among the 843 subjects tested for all HBV markers (Anti-HBc, HBsAg, HBsAb, and HBeAg), the prevalence of Anti-HBc, HBsAg, HBsAb, and HBeAg was found to be 57% (CI 95%:53-60%), 6% (CI 95%:4.0-8.0%), 37% (CI 95%:34-40%) and 9% (CI 95%:7-11%) respectively. P < 0.05.

Conclusion

Seroprevalence of all HBV markers (P < 0.05) was found to be significantly high, while the rate of immunity against HBV infection was low among health care workers In Public Teaching Hospitals in Khartoum State, Sudan.     

Air pollution transport in the Balkan region and country-to-country pollution exchange between Romania, Bulgaria and Greece

US EPA Models-3 system is used for calculating the exchange of ozone pollution between three countries in southeast Europe. For the purpose, three domains with resolution 90, 30 and 10 km are chosen in such a way that the most inner domain with dimensions 90 × 147 points covers entirely Romania, Bulgaria and Greece.The ozone pollution levels are studied on the base of three indexes given in the EU Ozone Directive, mainly accumulated over threshold of 40 ppb for crops (AOT40C, period May–July), number of days with 8-h running average over 60 ppb (NOD60) and averaged daily maximum (ADM). These parameters are calculated for every scenario and the influence of each country emissions on the pollution of the region is estimated and commented.Oxidized and reduced sulphur and nitrogen loads over the territories of the three countries are also determined. The application of all scenarios gave the possibility to estimate the contribution of every country to the S and N pollution of the others and detailed blame matrixes to be build.Comparison of the ozone levels model estimates with data from the EMEP monitoring stations is made.     

Inherently safer sustained casing pressure testing for well integrity evaluation

This paper presents the use of a model to predict sustained casing pressure (SCP), from early pressure buildup data, as a basis for inherently safer well integrity testing. Inherently safer principles aim to eliminate or reduce the hazards by design rather than by using protective features. SCP, a well integrity issue exhibited in many wells, is any measurable pressure that rebuilds after being bled down and attributable to causes other than artificially applied pressure or temperature fluctuations in the well. Intrusion of gas, resulting in SCP, can occur because of poor cement bond in the casing or cement deterioration. Gas entering the annulus migrates to the wellhead and represents a hazard due to increased wellhead pressure and the gas inventory. Compromised well integrity can have catastrophic consequences on both environmental and safety aspects.Most regulations require the monitoring, testing and, eventually, the elimination of SCP. However, test data analysis is predominantly qualitative and limited to arbitrary criteria. Due to the high percentage of wells that present SCP, accurate, safe and preferably fast testing methods are needed. This paper implements an analytical model, rooted in the transport processes and thermodynamics of the system, to predict pressure profiles and gas accumulation during SCP testing from early-time pressure buildup data. The amount of gas accumulated during different testing criteria, being 1) current practices and 2) early diagnostic by the analytical model, is calculated and compared. Results show that using the analytical model as a predictive tool, testing time is reduced significantly, thereby limiting the amount of gas accumulated and reducing the risk. This makes the testing procedure inherently safer as well as less time consuming.     

超声波/零价铁(US/Fe)协同降解氯酚类化合物的QSPR研究

在同一反应条件下测定US/Fe协同降解6种氯酚类化合物的降解速率常数(κ).采用软件Chemoffice2005内置的MOPAC2002计算氯酚类化合物的分子结构参数,运用偏最小二乘(PLS)回归分析方法,对氯酚类化合物进行定量结构-性质相关(QSPR)研究,得到预测性较好的模型.模型结果显示,影响US/Fe协同降解性能(logK)的主要因素是Vp、Ehomo、logKow、(Elumo-Ehomo)2和Elumo-Ehomo.推测在US/Fe协同体系中:(1)氯酚类化合物的降解反应不是以空化泡内热解反应为主;(2)Fe表面的吸附作用对降解反应起决定影响,且氯酚化合物与·OH的氧化反应占主导作用.     

超声气升式环流反应器降解乐果水溶液的动力学研究

采用超声气升式环流反应器(UALR),以臭氧气体为氧化剂,以有机磷农药乐果为典型污染物,研究其降解反应动力学规律.通过对乐果降解过程的表观动力学研究,发现乐果在单独超声辐射(不通入气体,即臭氧)、臭氧(O3)氧化和超声气升式环流反应器(UALR/O2)协同下的降解均符合表观一级动力学.在乐果初始质量浓度为50 mg/L、溶液初始pH为6.0、反应液体积80 mL、超声声强0.5W/cm2、O3流量200 L/h、温度20℃、处理时间4h的条件下,采用超声(US)、O3和UALR/O3工艺,乐果的去除率分别为27%、15%和90%,乐果降解的速率常数增强因子可达到4.816.进一步从UALR/O3系统中存在US、O3和羟基自由基(·OH)协同作用的降解机理,推导出了简化的机理动力学模型.     

天津市大气颗粒物中有机标识物粒径分布的季节特征

为探讨采暖季和非采暖季大气颗粒物中有机标识组分的粒径分布特征,识别其来源,于2018年5月至2019年4月在天津采集分粒径颗粒物,利用GC-MS对9个粒径段颗粒物中17种多环芳烃(PAHs)、20种正构烷烃(n-Alkanes)和7种藿烷(hopanes)进行分析,并通过有机标识物及特征比值的方法探讨其主要来源.结果表明:非采暖季的四环多环芳烃Pyr、Ba A、Chr和五环多环芳烃BbF、Ba P呈3峰分布,其余PAHs呈双峰分布,采暖季的低环PAHs呈双峰分布,中高环PAHs近似单峰分布.根据PAHs特征比值发现,非采暖季的燃煤源和交通源是PAHs的主要贡献源,采暖季PAHs受燃煤源的影响更显著.非采暖季的正构烷烃中C29呈单峰分布,C27、C31、C32和C33近似单峰分布,其余正构烷烃呈双峰分布,采暖季的正构烷烃均呈双峰分布.根据正构烷烃碳优势指数(CPI)和主碳峰数(C_max)发现,人为源是正构烷烃的主要来源,非采暖季受自然源的影响大于采暖季,自然源排放的正构烷烃倾向于富集在粗颗粒物上,人为源排放的正构烷烃则更倾向于富集在细颗粒物上.藿烷在粗粒径段和细粒径...     

全氟辛烷磺酸对斑马鱼肝脏影响机制的代谢组学研究

为探究全氟辛烷磺酸(PFOS)对水生动物肝脏的慢性毒性毒害机制,寻找其肝脏慢性毒性相关的潜在标志物,运用气相色谱-质谱联用仪代谢组学方法研究暴露于PFOS中斑马鱼肝脏内源性代谢物的变化,寻找显著性差异代谢物及相关通路。实验分为4组:对照组及PFOS浓度分别为10、100、250μg·L~(-1)的实验组,每组20尾斑马鱼,实验时长40 d。结果显示,与对照组相比,PFOS浓度为10μg·L~(-1)的斑马鱼肝脏中筛选出4种发生显著性变化的代谢物,分别为牛磺酸、磷酸乙酰胺、β-D-葡萄糖、油酸,涉及4条代谢通路,即牛磺酸和亚牛磺酸代谢、鞘脂代谢、甘油磷脂代谢、糖酵解或葡萄糖生成。100μg·L~(-1)浓度组的斑马鱼肝脏中筛选出5种,包括牛磺酸、β-D-葡萄糖、棕榈酸、油酸、胆固醇,涉及5条代谢通路,即原代胆汁酸生物合成、牛磺酸和亚牛磺酸代谢、类固醇生物合成、类固醇激素生物合成、糖酵解或葡萄糖生成。250μg·L~(-1)浓度组的斑马鱼肝脏中筛选出5种,即牛磺酸、β-D-葡萄糖、乳酸、甘油-3-磷酸、磷酸乙酰胺,涉及5条代谢通路:牛磺酸和亚牛磺酸代谢、甘油磷脂代谢、甘油脂代谢、鞘脂代谢、糖酵解或葡萄糖生成。根据筛选出的差异代谢物生理功能和其涉及代谢通路分析,推测PFOS主要通过影响牛磺酸和亚牛磺酸代谢、糖酵解或葡萄糖生成及一些脂类代谢从而对斑马鱼肝脏产生毒性效应,其中牛磺酸、葡萄糖与油酸这3种代谢物可作为斑马鱼受PFOS胁迫肝脏代谢异常的潜在标记物。     

Molecular approaches to microbiological monitoring: fecal source detection

Molecular methods are useful both to monitor natural communities of bacteria, and to track specific bacterial markers in complex environments. Length-heterogeneity polymerase chain reaction (LH-PCR) and terminal restriction fragment length polymorphism (T-RFLP) of 16S rDNAs discriminate among 16S rRNA genes based on length polymorphisms of their PCR products. With these methods, we developed an alternative indicator that distinguishes the source of fecal pollution in water. We amplify 16S rRNA gene fragments from the fecal anaerobic genus Bacteroides with specific primers. Because Bacteroides normally resides in gut habitats, its presence in water indicates fecal pollution. Molecular detection circumvents the complexities of growing anaerobic bacteria. We identified Bacteroides LH-PCR and T-RFLP ribosomal DNA markers unique to either ruminant or human feces. The same unique fecal markers were recovered from polluted natural waters. We cloned and sequenced the unique markers; marker sequences were used to design specific PCR primers that reliably distinguish human from ruminant sources of fecal contamination. Primers for more species are under development. This approach is more sensitive than fecal coliform assays, is comparable in complexity to standard food safety and public health diagnostic tests, and lends itself to automation and high-throughput. Thus molecular genetic markers for fecal anaerobic bacteria hold promise for monitoring bacterial pollution and water quality.