1,500 research outputs found

    The effect of cadmium on the bovine in vitro oocyte maturation and early embryo development

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    Common pollutants such as heavy metals and cadmium is among those with high environmental concerns. In vivo studies had shown that cadmium (Cd) causes oocyte degeneration and embryo mortality, and lowers pregnancy rates in mammals. However, there is limited information available about direct effects of Cd on oocyte maturation and/or embryo development. This study was aimed to investigate if Cd has any effect on the oocyte maturation and/or embryo development in vitro. Bovine COCs were collected from the slaughter house and cultured for 24 h in serum-free media only (Controls) or supplemented with 0.2, 2.0 and 20.0 μM CdCl2. At 24 h cumulus cell expansion was assessed in all COCs. COCs were either denuded and stained for determination of nuclear maturation or fertilized for assessment of subsequent embryo development. Cd at the lowest concentration (0.2 μM) did not affect any of the parameters studied. However, at higher concentrations (2.0 and 20.0 μM) it significantly (P < 0.05) reduced the percentage of fully-expanded COCs and significantly (P < 0.05) increased the percentage of partially and/or non-expanded COCs compared to controls and 0.2 μM. Cadmium at higher concentrations (2.0 and 20.0 μM) also significantly (P < 0.01) reduced the percentage of oocytes reaching metaphase II stage compared to controls and 0.2 μM. Post-fertilization cleavage rate in presumptive zygotes and blastocyst development significantly (P < 0.05) reduced 0.2, 2.0 and 20.0 μM CdCl2 compared to the controls (0.0 μM). In conclusion, these results suggest that Cd had direct detrimental effects on the bovine oocyte maturation and its developmental competence

    Temporal Variability of Urinary Phthalate Metabolite Levels in Men of Reproductive Age

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    Phthalates are a family of multifunctional chemicals widely used in personal care and other consumer products. The ubiquitous use of phthalates results in human exposure through multiple sources and routes, including dietary ingestion, dermal absorption, inhalation, and parenteral exposure from medical devices containing phthalates. We explored the temporal variability over 3 months in urinary phthalate metabolite levels among 11 men who collected up to nine urine samples each during this time period. Eight phthalate metabolites were measured by solid-phase extraction–high-performance liquid chromatography–tandem mass spectrometry. Statistical analyses were performed to determine the between- and within-subject variance apportionment, and the sensitivity and specificity of a single urine sample to classify a subject’s 3-month average exposure. Five of the eight phthalates were frequently detected. Monoethyl phthalate (MEP) was detected in 100% of samples; monobutyl phthalate, monobenzyl phthalate, mono-2-ethylhexyl phthalate (MEHP), and monomethyl phthalate were detected in > 90% of samples. Although we found both substantial day-to-day and month-to-month variability in each individual’s urinary phthalate metabolite levels, a single urine sample was moderately predictive of each subject’s exposure over 3 months. The sensitivities ranged from 0.56 to 0.74. Both the degree of between- and within-subject variance and the predictive ability of a single urine sample differed among phthalate metabolites. In particular, a single urine sample was most predictive for MEP and least predictive for MEHP. These results suggest that the most efficient exposure assessment strategy for a particular study may depend on the phthalates of interest

    Исследование влияния природы растворителя, используемого при получении электродной мембраны, на работу Ni-селективного электрода при определении ионов никеля (LL) в водных средах

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    Исследовано влияние природы растворителей (бензиловый спирт и хлорфенол), используемых для изготовления полимерной электродной мембраны твердофазного никельселективного электрода на основе никельгексационоферратов ({Ni2[Fe(CN)6]}), иммобилизованных в полиэтилентерефталатную (ПЭТФ) матрицу для определения ионов никеля в водных средах. Установлено, что мембраны, полученные на основе бензилового спирта имеют более высокие электродные показатели по сходимости и воспроизводимости потенциалов, стабильности работы, низком дрейфе и времени отклика электрода по сравнению с мембранами на основе хлорфенола и могут быть рекомендованы к использованию в никель селективных электродах.The influence of the nature of the solvents (benzyl alcohol and chlorophenol) used to fabricate a polymer electrode membrane of a solid-phase nickel selective electrode based on nickelhexacetanoferrates ({Ni2 [Fe (CN) 6]}) immobilized in a polyethylene terephthalate (PET) matrix for the determination of nickel ions in aqueous media . It has been established that membranes obtained on the basis of benzyl alcohol have higher electrode indices for the convergence and reproducibility of potentials, stability of operation, low drift and electrode response time compared to chlorophenol-based membranes, and can be recommended for use in nickel selective electrodes

    Implementation of REACH in the New Member States - Part two: Business Case Studies in Selected New Member States

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    This report informs about potential impacts of the European regulation concerning the registration, evaluation, authorisation and restriction of chemicals REACH (Regulation (EC) No 1907/2006) in the New Member States . It consists of two parts: 1) "Implementation of REACH in the New Member States – Part one: overview of the chemical and specialty chemical sector in the New Member States", and 2) "Implementation of REACH in the New Member States – Part two: Business case studies in selected New Member States". The first report gives a general overview of the chemical sector in all New Member States and provides key macroeconomic data for the description of the chemical sector as a whole in each of the countries. This includes the sectors development, major developments including trade with EU-15 and non-EU countries, and a description of sub-sectors according to NACE categories. Furthermore, the first report describes the impact on the chemical industry through the implementation of the Chemicals Acquis and the Accession to the EU, and derives the implications for the adoption of REACH in the New Member States. Finally, the report outlines REACH Impact studies which are available in the New Member States . The second report analyses the ability of specialty chemicals companies in selected countries to implement REACH . This ability is examined on the basis of techno-economic case studies. From the economic aspect, the impact on costs and prices is analysed, substance withdrawal, administrative impact, capacity needs and the competitiveness on European and international markets. From the technological point of view the impact of REACH on innovation, replacement of substances and process adaptation is looked at. The strategic analysis looked at alternatives to cope with REACH (such as the import of components, relocation to non-EU countries etc.), the potential of companies to adapt to the changing legal framework (including the implementation of the environmental acquis) and the relative importance of REACH as one amongst different drivers for change.JRC.J.2-Competitiveness and Sustainabilit

    Reservoir fracture characterizations from seismic scattered waves

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    The measurements of fracture parameters, such as fracture orientation, fracture density and fracture compliance, in a reservoir is very important for field development and exploration. Traditional seismic methods for fracture characterization include shear wave birefringence (Gaiser and Dok, 2001; Dok et al., 2001; Angerer et al., 2002; Vetri et al., 2003) and amplitude variations with offset and azimuth (AVOA) (Ruger, 1998; Shen et al., 2002; Hall et al., 2003; Liu et al., 2010; Lynn et al., 2010). These methods are based on the equivalent medium theory with the assumption that fracture dimension and spacing are small relative to the seismic wave length, so a fracture zone behaves like an equivalent anisotropic medium. But fractures on the order of seismic wave length are also very important for enhanced oil recovery, and they are one of the important subsurface scattering sources that generate scattered seismic waves. Willis et al. (2006) developed the Scattering Index method to extract the fracture scattering characteristics by calculating the transfer funtion of a fracture zone. Fang et al. (2011) proposed a modification of the SI method (the Fracture Transfer Function (FTF) method) that leads to a more robust fracture characterization. In this paper, we use both laboratory data and field data to explore the capability of the FTF method.Eni-MIT Energy Initiative Founding Member Progra
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