Comparative study of the microstructural and magnetic properties of fly ashes obtained from different thermal power plants in West Bengal, India

This paper deals with the physical nature of the fly ashes obtained from two thermal power plants, situated in West Bengal, India. The fly ash samples are characterized by using comprehensive techniques with an emphasis on their ultrafine nature. The particle sizes of the samples are estimated using scanning electron microcopy (SEM) and found to lie within 0.18–5.90 μm. For morphology and compositional analysis, we also use SEM coupled with energy dispersive X-ray spectrometry. From X-ray study of the fly ashes the nature of conglomeration is seen to be crystalline, and the major components are mullite (Al₆Si₂O₁₃) and quartz (SiO₂). The magnetic measurement of the fly ash samples was carried out by SQUID magnetometer. ⁵⁷Fe Mössbauer spectra are obtained using a conventional constant-acceleration spectrometer with a ⁵⁷Co/Rh Mössbauer source. The hyperfine parameters obtained, in general, support the findings as made from XRD analysis and provide a quantitative measure of different iron ions present in the samples. The paper presents experimental data on the physical aspects of the fly ash samples of the thermal power plants which comprise coarse, fine, and ultrafine magnetic particulate materials and attempts to provide an exhaustive analysis.     

Antioxidant responses of the earthworm Lampito mauritii exposed to Pb and Zn contaminated soil

The aim of this study was to provide fundamental data on the biochemical analysis of antioxidant defences in the earthworm exposed to low levels (75, 150, 300 mg kg(-1) soil) of Pb and Zn. In order to attain this objective, adult Lampito mauritii were exposed to different doses of Pb and Zn separately for 28 days and the concentrations of oxidized and reduced glutathione, activities of glutathione-S-transferase, glutathione peroxidase and glutathione reductase were assessed. Dose-dependent perturbations were observed in the glutathione-glutathione-S-transferase system and other antioxidant enzymes during the early phase of the exposure to Pb. In the Zn exposed earthworm, the glutathione-glutathione-S-transferase system remained stable and the stimulation of glutathione peroxidase and glutathione reductase activities occurred significantly only on day 14 at 300 mg Zn kg(-1). It is concluded that the antioxidants are directly involved in the adaptive response of Lampito mauritii for survival in metal contaminated soil.     

渤海湾两条河流及其近岸海域水体中DOM的光谱特征及影响因素

应用三维荧光光谱结合吸收光谱分析,研究了2019年夏季天津市大清河-独流减河水系和河北省黄骅市捷地减河及其河口区水体中溶解有机物（DOM）的空间分布特征、来源及其影响因素。紫外-可见光谱结果表明,研究区水体的SUVA₂₅₄与盐度有显著正相关关系;两条河流的下游水体中S_275-295均值均大于上游和中游。平行因子分析结果表明,两条河流均检测到两种类腐殖质组分C1（240,300/390 nm）和C3（260,335/477 nm）以及一种类蛋白质组分C2（225,275/339 nm）。在大清河-独流减河水系及其近岸海域水体中,这三种组分与盐度呈显著负相关关系,其中由于人为输入（TN和TP含量高,工业排污）影响导致C2与盐度的相关性弱于C1和C3。该水系水体在低盐度时C2的占比高于捷地减河,主要受到工农业废水输入与其支流子牙河汇入的共同影响,而捷地减河主要受农业废污水输入的影响。此外,自然因素（盐度、海水混合）和人为因素（人为输入、筑坝拦截）的不同导致渤海湾两条入海河流中有色溶解有机质（CDOM）的光学特性和混合行为出现显著差异。其中筑坝拦截导致独流减河坝前水体的CDOM平均分子量低于下游水体,并且增强了河口区陆源类腐殖质的去除作用。综上,三维荧光光谱结合平行因子分析能判别河流局部条件的差异对整体CDOM空间分布特征的影响,研究结果可为渤海湾地区河流及河口水体CDOM生物地球化学过程研究提供基础数据。     

Sex-specific difference of alkaline phosphatase of Ehrlich's carcinoma cells

The Science of Nature -     

Sonographic demonstration of fetal sacrococcygeal teratoma

Six cases of sonographically diagnosed fetal sacrococcygeal teratoma (SCT) are presented and illustrate the variable features of fetal SCT. The sonographic findings assisted the parents and perinatal team in making decisions, and in two of the cases the children survived after elective Cesarean section and prompt neonatal resection of the tumors. None of the patients showed signs of malignant degeneration of the teratoma or metastases. Fetal SCT no longer should be considered a uniformly fatal condition. The literature on sacrococcygeal teratoma detected after birth indicates that the mortality rate is correlated with the degree of extension of the tumor. Therefore, the classification of sonographically diagnosed fetal SCT according to its size and position is important for decisions regarding pregnancy management.     

Dioxins and furans in the atmosphere of São Paulo City, Brazil

Air samples were collected simultaneously at three urban sites in São Paulo City, Brazil, in winter, spring, summer and fall (in 2000 and 2001). Andersen PUF samplers were used for gas and particles sequential sampling. Samples were analyzed using HRGC/HRMS according to US EPA Method 8290. The greater metropolitan area of São Paulo is the largest industrialized region of Latin America and has a highly polluted atmosphere. Concentrations of dioxins and furans, which are well-known toxic chemicals, ranged from 1.14 pg m⁻³ to 13.8 pg m⁻³ (0.047 pg I-TEQ m⁻³ to 0.751 pg I-TEQ m⁻³). Principal component analysis showed that all the variables are highly correlated with one another except the 2,3,7,8-TCDD one. This is consistent with the similar concentration profiles observed for the tetra, penta, hexa, hepta and octa-homologous groups of the three sampling sites studied. At all sites, the most abundant compounds were the hepta and octa congeners. The 2,3,4,7,8-PeCDF accounted for 37–46% of the total toxicity and the 2,3,7,8-TCDD accounted for 7–16%. Highest mass concentrations of PCDD/Fs were found in the site where there is influence of industrial activities and heavy vehicular traffic fueled by gasohol, diesel, and ethanol.     

Manganese content of Tradescancia species exposed to automotive combustion of methylcyclopentadienyl manganese tricarbonyl in urban and rural landscapes

The purpose of this study is to assess the effect of manganese (Mn) from methylcyclopentadienyl manganese tricarbonyl (MMT) on grass (Tradescancia) species beside the major urban and rural highways in the greater Toronto area. Grass clippings were collected at distances up to 40 m from the roadside of a wooded, weakly exposed site (E+) and two unwooded, highly exposed sites (E++ and E+++) to Mn contamination. Statistical tests, including analysis of variance and correlation coefficients, were used to compare the Mn deposition on grass species with respect to distance and traffic density. A higher deposition of Mn was expected at the highly exposed sites when compared with the weakly exposed site, but a significantly higher concentration of Mn was observed at weakly exposed rural E+ site (Mn = 54.07 microg/g; dry wt) than the highly exposed urban E++ (Mn = 38.17 microg/g; dry wt) and E+++ (Mn = 35.63 microg/g; dry wt) sites. A significant correlation coefficient was found for Mn and traffic density (r2 = 0.311, p = 0.0074) at the weakly exposed site than at the highly exposed (r2 = 0.1589, p = 0.1052) urban sites. These data demonstrate that despite the continuous use of MMT in Canadian gasoline, the levels do not appear to exceed the worldwide tolerable levels (17-334 g/g; dry wt) in grass species inhabiting ecosystems next to major highways in urban regions.     

Phototransformation of clodinafop-propargyl

Photodegradation of the herbicide clodinafop-propargyl was investigated on glass surface under sunlight and UV light. Four photoproducts were identified by NMR, IR, and MS. Major photolysis products were 2-[(5-chloro-3-fluoro-2-pyridyloxy) phenoxy] propanoic acid and prop-2-ynyl-2-[(5-chloro-3-hydroxy-2-pyridyloxy) phenoxy] propanoate, while minor were ethyl 2-[(5-chloro-3-fluoro-2-pyridyloxy) phenoxy] propanoate and 1-hydroxypropanyl-2-[(5-chloro-3-fluoro-2-pyridyloxy) phenoxy] propanoate. Rate of photodegradation followed first-order kinetics with significant correlation coefficient. The major photoproducts were observed in maximum quantity on the 7th and 10th day and further degraded within 15-20 days.