Investigating compensation and recovery of fathead minnow (Pimephales promelas) exposed to 17alpha-ethynylestradiol with metabolite profiling

1H NMR spectroscopy was used to profile metabolite changes in the livers of fathead minnows (Pimephales promelas) exposed to the synthetic estrogen 17alpha-ethynylestradiol (EE2) via a continuous flow water exposure. Fish were exposed to either 10 or 100 ng EE2/L for 8 days, followed by an 8 day depuration phase. Livers were collected after days 1, 4, and 8 of the exposure, and at the end of the depuration phase. Analysis of polar extracts of the liver revealed a greater impact of EE2 on males than females, with metabolite profiles of the former assuming similarities with those of the females (i.e., feminization) early in the exposure. Biochemical effects observed in the males included changes in metabolites relating to energetics (e.g., glycogen, glucose, and lactate) and liver toxicity (creatine and bile acids). In addition, amino acids associated with vitellogenin (VTG) synthesis increased in livers of EE2-exposed males, a finding consistent with increased plasma concentrations of the lipoprotein in the fish. Using partial least-squares discriminant analysis (PLS-DA), the response trajectories of the males at both exposure concentrations were compared. This revealed an apparent ability of the fish to compensate for the presence of EE2 later in the exposure, and to partially recover from its effects after the chemical was removed.     

A CL mode detector for rapid catalyst selection and environmental detection fabricated by perovskite nanoparticles

La(1-x)Sr(x)MnO3 (x = 0, 0.2, 0.5, 0.8) nanoparticles were synthesized and their chemiluminescence (CL) and catalytic properties of CO oxidation were determined. We mainly investigated the influences of filter band length, flow rate of gas, test temperature, catalyst compositions, and particle size on CL intensities and catalytic activities of the catalysts. The catalysts were characterized by means of XRD, TEM, N2 adsorption isotherm, CO-TPD, and O2-TPD, etc. It was found that the strong CL response signals occurred over these perovskites nanoparticles; and that CL properties of the catalysts were well correlated with the reaction activities. These nanoparticles can be used to fabricate a stable gas detector due to a high activity and stability of perovskite structure. CL mode could be a rapid and effective method for the selection of new catalysts from thousands of materials, as well as for the detection of environmental deleterious gases.     

响应面法优化超声-微波协同萃取蓝藻中叶绿素a工艺研究

为了探索蓝藻叶绿素a的最佳萃取工艺参数,在单因素试验基础上,选取乙醇体积分数、萃取时间以及液固体积质量比为自变量,叶绿素a萃取得率为响应值,采用中心组合设计的方法,研究各自变量及其交互作用对响应值叶绿素a萃取率的影响。利用响应面分析方法,模拟得到了2次多项式回归方程的预测模型,并确定叶绿素a萃取工艺的最佳参数:乙醇体积分数86%、时间133 s、液固体积质量比16∶1(mL∶g),在开启超声波、微波功率250 w、萃取两次的条件下,叶绿素a萃取率达到(2.686±0.013)mg/g。     

空心结构沸石分子筛合成研究进展

空心结构沸石分子筛具有由沸石分子筛微孔构成的壳层及由微孔孔道环绕形成的介孔或大孔空腔,呈现出特殊的、优异的性能,成为化学和新材料科学等领域研究热点,其合成和制备受到越来越多的关注.本文对空心结构沸石分子筛的合成方法进展进行总结阐述,指出扩展空心结构沸石在新兴领域的应用,开发出普适性、重现性好,成本低廉易于工业化合成方法...     

乳酸菌纯种发酵辣椒酱工艺研究

乳酸菌纯种发酵辣椒酱的最优生产工艺：接种量为5％、发酵温度35℃、发酵时间48h、菌种配比Lact．1：Lact．2为2：1。纯菌种发酵的辣椒过程中亚硝酸盐含量最高值仅为0．637mg／kg,而自然发酵时可达6．874mg／kg。     

Microplastics in soils: a review of possible sources,analytical methods and ecological impacts

Microplastics are emerging persistent pollutants that have been extensively detected in aqueous environments. Yet, scientists have little knowledge of microplastic pollution in soils. This study reviewed over 60 articles, with the following objectives: (i) to discuss sources and the global distribution of microplastics in soils; (ii) to evaluate current extraction techniques and analytical methods for microplastics in soils; and (iii) to comprehensively assess their adverse impacts on soils and soil organisms. Moreover, this review highlights the lack of research into microplastic contamination in soils as a significant knowledge gap. Research into the fate, sources and analytical techniques of soil microplastics and the interactions between soil organisms, soils and microplastics is essential in order to underpin management decisions aimed at safeguarding the ecological integrity of our soils. © 2020 Society of Chemical Industry     

Effect of microwave sintering on the properties of copper oxide doped Y-TZP ceramics

The effect of various amounts of copper oxide (CuO) up to 1?wt% on the densification behaviour and mechanical properties of 3?mol% yttria-tetragonal zirconia polycrystal (Y-TZP) were studied by using microwave (MW) sintering method. The MW sintering was performed at temperatures between 1100?°C and 1400?°C, with a heating rate of 30?°C/min. and holding time of 5?min. The beneficial effect of MW in enhancing densification was also compared for the undoped and 0.2?wt% CuO-doped Y-TZP when subjected to conventional sintering (CS) method. The results showed that significant enhancement in the relative density and Vickers hardness were observed for the undoped Y-TZP when MW-sintered between 1100?°C and 1250?°C. It was revealed that the 0.2?wt% CuO-doped Y-TZP and MW sintered at 1250–1300?°C could attain ≥?99.8% of theoretical density, Vickers hardness of about 14.4?GPa, fracture toughness of 7.8 MPam^1/2 and exhibited fine equiaxed tetragonal grain size of below 0.25?µm. In contrast, the addition of 1?wt% CuO was detrimental and the samples exhibited about 50% monoclinic phase upon sintering coupled with poor bulk density and mechanical properties. The study also revealed that the addition of 0.2?wt% CuO and subjected to conventional sintering produced similar densification as that obtained for microwave sintering, thus indicating that the dopant played a more significant role than the sintering method.     

Strength improvement in silty clay by microbial-induced calcite precipitation

Bulletin of Engineering Geology and the Environment - The application of MICP (microbial-induced calcite precipitation) to clays has been restricted due to their low permeability and small pore...     

丹尼尔斯大厦 加拿大多伦多

正多伦多大学丹尼尔斯建筑、景观和设计学院的设计采用了分期的方法,包括修复和扩建以前称为"知识学院"的标志性建筑,将现有建筑物改造成与教学和需求更相关的框架体系。这个十九世纪遗址的总体规划是通过对预期用途模式和场地生态的分析而制定的,目的是重新定位校园西南角与安大略湖的轴线,并为学院创造新的特性。丹尼尔斯建筑、景观和设计学院需要一个可持续发展的新型工