Detection of fullerenes (C60 and C70) in commercial cosmetics

Detection methods are necessary to quantify fullerenes in commercial applications to provide potential exposure levels for future risk assessments of fullerene technologies. The fullerene concentrations of five cosmetic products were evaluated using liquid chromatography with mass spectrometry to separate and specifically detect C₆₀ and C₇₀ from interfering cosmetic substances (e.g., castor oil). A cosmetic formulation was characterized with transmission electron microscopy, which confirmed that polyvinylpyrrolidone encapsulated C₆₀. Liquid-liquid extraction of fullerenes from control samples approached 100% while solid-phase and sonication in toluene extractions yielded recoveries of 27-42%. C₆₀ was detected in four commercial cosmetics ranging from 0.04 to 1.1 μg/g, and C₇₀ was qualitatively detected in two samples. A single-use quantity of cosmetic (0.5 g) may contain up to 0.6 μg of C₆₀, demonstrating a pathway for human exposure. Steady-state modeling of fullerene adsorption to biosolids is used to discuss potential environmental releases from wastewater treatment systems.     

枯草芽孢杆菌对Cu2+的吸附及菌体表面基团分析

以枯草芽孢杆菌(Bacillus subtilis)为生物吸附剂,讨论了其对Cu2+的生物吸附规律,并通过酸碱滴定这一表面分析手段,结合相关软件及傅里叶变换红外光谱(FTIR)分析了菌体表面主要的基团种类及数量.结果表明,枯草芽孢杆菌对Cu2+吸附的最佳条件是:pH为6、吸附时间为24 h,菌悬液用量和Cu2+初始浓度...     

Virgin and recycled engine oil differentiation: a spectroscopic study

As a result of the changes that occur during their use, used engine oils tend to differ in chemical and physical composition from a virgin oil. In general recycled oils have: much higher water and sediment levels than virgin oil; relatively higher concentrations of organic compounds (oxidation products); and relatively higher levels of metals such as Fe, Cd, Cr, Pb, etc. Therefore, the aim of this work was to investigate, assess and to observe, by means of the physical and the chemical properties of the oils, atomic absorption (AA), inductive couple plasma (ICP) and Fourier transform infrared (FTIR) analyses the extent of the differences occurring between the virgin and recycled oil. In important part of this work was also the development of analytical techniques based on the use of FTIR spectroscopy; in relation to the rapid analysis of lubricants; in particular for the differentiation of virgin and recycled oil. The results obtained were expected to be useful for differentiation purposes, providing information on whether the metal concentrations and oxidation products could be an appropriate feature for differentiating a particular oil sample from the others. This work is categorized into a two-step procedure. Firstly, an evaluation of a typical FTIR spectrum of an engine oil sample (mono- and multigrade) is presented. The broad feature centered at 1716 cm(-1) is due to the presence of carbonyl containing degradation products of oil. A band observed at 1732, 1169, 1154 and 1270 cm(-1) assigned to the polymethacrylate stretching vibrations, allows the determination of viscosity modifier and pour point depressant additives. The observed differences in the specific spectral bands (1732, 1169, 1154 and 1270 and 1716 cm(-1)) are investigated and discussed. Secondly, an analytical technique for the measurement of the levels of the wear metals is also applied.     

基于离散余弦变换的鲁棒感知图像哈希技术

对现有感知图像哈希的生成方法进行深入研究,分析该方法存在的不足之处。分别介绍离散余弦变换、Watson视觉模型和混沌模型的原理和特点,提出将这3种模型进行融合来设计感知图像哈希的生成方法。该方法采用离散余弦变换提取图像特征,对比敏感表对特征向量进行处理并用Logistic方程作为混沌序列发生器进行加密,最后采用预测差分方法进行量化编码。试验结果表明:该方法可以抵抗内容保持的修改操作,并具有较强的鲁棒性、安全性和检索性,且冲突概率降低到10-7数量级。该技术在图像认证、版权保护、安全和基于内容的图像检索等方面有应用价值。     

基于傅里叶级数的自然灾害损失预测模型研究——以湖南省自然灾害经济损失预测为例

针对湖南省自然灾害经济损失发生的现状,结合傅里叶级数的相位特征,利用傅里叶级数时间序列模型给出自然灾害损失的变化趋势。根据1986—2007年湖南省自然灾害所造成的直接经济损失数据,在SPSS环境下进行拟合,并对未来5年湖南省的自然灾害所造成的直接经济损失进行预测。结果表明:傅里叶级数时间序列模型符合自然灾害损失发生的特点,有效地解决了传统损失预测模型在灾害经济损预测中误差大、稳定性差的缺陷,提高了预测精度;且得出未来5年湖南灾害灾情仍然具有递增的趋势的结论。采用该模型对自然灾害损失进行预测,其结果比较可靠,可供减灾决策部门参考。     

Phenanthrene uptake by Medicago sativa L. under the influence of an arbuscular mycorrhizal fungus

Phenanthrene uptake by Medicago sativa L. was investigated under the influence of an arbuscular mycorrhizal fungus. Inoculation of lucerne with the arbuscular mycorrhizal fungus Glomus etunicatum L. resulted in higher phenanthrene accumulation in the roots and lower accumulation in the shoots compared to non-mycorrhizal controls. Studies on sorption and desorption of phenanthrene by roots and characterization of heterogeneity of mycorrhizal and non-mycorrhizal roots using solid-state ¹³C nuclear magnetic resonance spectroscopy (¹³C NMR) demonstrated that increased aromatic components due to mycorrhizal inoculation resulted in enhanced phenanthrene uptake by the roots but lower translocation to the shoots. Direct visualization using two-photon excitation microscopy (TPEM) revealed higher phenanthrene accumulation in epidermal cells of roots and lower transport into the root interior and stem in mycorrhizal plants than in non-mycorrhizal controls. These results provide some insight into the mechanisms by which arbuscular mycorrhizal inoculation may influence the uptake of organic contaminants by plants.     

Enhanced degradation of bioremediation residues in petroleum-contaminated soil using a two-liquid-phase bioslurry reactor

A study was performed to determine the potential of two-liquid-phase (TLP) bioslurry reactors using silicon oil as solvent for degradation of residual contaminants in petroleum-contaminated soil. The residues were characterized by gas chromatography–mass spectrometry and electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry. This allowed for the identification of a mixture of residual biomarkers, metabolic byproducts, oxygenated and hetero-polynuclear aromatic hydrocarbons in the contaminated soil. The removal amount of total extractable organics (TEO) was 15 900 mg kg⁻¹ soil in the TLP reactor within 12 weeks. However, TEO remained intact in the bioslurry reactor without the addition of silicon oil for the duration of the experiment, due to high toxicity of metabolites to the microorganisms. The availability of TEO was calculated using a mild extraction with Triton X-100, and the amount of TEO extracted was in accord with the amount of biodegraded TEO. Significantly reduced toxicity in soil was observed at week 12 through TLP remediation. Dehydrogenase activity in the bioslurry reactor was strongly suppressed. Fluorescein diacetate was significantly hydrolyzed by the composition of bioremediation residues in the contaminated soil. Microbial adhesion to the solvent was revealed by the determination of microbial activity in the water-immiscible-liquid.     

Structural characterization and thermal stabilities of the isomers of the brominated flame retardant 1,2,5,6-tetrabromocyclooctane (TBCO)

1,2,5,6-Tetrabromocyclooctane (TBCO) is a commercial brominated flame retardant that is employed mainly as an additive in textiles, paints and plastics. Very little is known about its presence or behavior in the environment or its analysis. TBCO can exist as two diastereomers, the stereochemistries of which have not been previously reported. We have named the first eluting isomer, under HPLC conditions, as alpha-TBCO (α-TBCO) and the later eluting isomer as beta-TBCO (β-TBCO) when using an Acquity UPLC BEH C₁₈ column with methanol/acetonitrile/water as the mobile phase. The structural elucidation of these two isomers was accomplished by ¹H NMR spectroscopy, GC/MS, LC/MS and X-ray structure determinations. α-TBCO is (1R,2R,5S,6S)-1,2,5,6-tetrabromocyclooctane and β-TBCO is rac-(1R,2R,5R,6R)-1,2,5,6-tetrabromocyclooctane. As with some other brominated cycloaliphatic compounds, TBCO is thermally labile and the isomers easily interconvert. A thermal equilibrium mixture of α- and β-TBCO consists of approximately 15% and 85% of these isomers, respectively. Separation of the two diastereomers, with minimal thermal interconversion between them, is achievable by careful selection of GC-capillary column length and injector temperature. LC/MS analyses of TBCO also presents an analytical challenge due to poor resolution of the isomers on chromatographic stationary phases, and weak intensity of molecular ions (or major fragment ions) when using LC-ESI/MS. Only bromide ions were seen in the mass spectra. APCI and APPI also failed to produce the molecular ion with sufficient intensity for identification.     

1H-NMR-based metabolomic study on toxicity of methomyl and methidathion in fish

A ¹H-nuclear magnetic resonance (NMR) spectroscopy with multivariate analysis was applied to detect the toxicity of antiacetylcholinesterase insecticides, methomyl (methyl (1E)-N-(methylcarbamoyloxy)ethanimidothioate) and methidathion (3-(dimethoxyphosphinothioyl sulfanylmethyl)-5-methoxy-1,3,4-thiadiazol-2-one), using zebrafish (Danio rerio) and Chinese bleak (Aphyocypris chinensis). Generally, methomyl and methidathion have been believed not to highly accumulate in fish tissues. However, these pesticides showed their toxicity by altering patterns of whole-body metabolites in neurotransmitter balance, energy metabolism, oxidative stress, and muscle maintenance in low concentrations. We used Pearson correlation analysis to contextualize the metabolic markers in pesticide treated groups. We observed that the positive correlations of choline with acetate and betaine in untreated control were shifted to null correlations showing acetylcholinesterase specific toxicity. This research demonstrated the applicability and potential of NMR metabolomics in detecting toxic effects of insecticide with a modicum of concentrations in aquatic environment.     

Polymer coating of copper oxide nanoparticles increases nanoparticles uptake and toxicity in the green alga Chlamydomonas reinhardtii

Copper oxide nanoparticles (CuO NPs) are frequently used in a polymer-coated form, to be included in paints or fabrics for antimicrobial properties. Their application in antifouling paints may lead to the contamination of aquatic ecosystems. However, the toxicological risk of NPs in the environment is hard to evaluate due to a lack of knowledge on the mechanisms of NP interaction with biological systems. In this study, we investigated the effect of polymer coating on CuO NP toxicity in the green alga Chlamydomonas reinhardtii by comparing bare and polymer-coated CuO NPs prepared from the same CuO nanopowder. Both CuO NP suspensions were toxic to C. reinhardtii after 6 h treatment to concentrations of 0.005-0.04 g L⁻¹. Bare and polymer-coated CuO NPs induced a decrease of Photosystem II activity and the formation of reactive oxygen species. Polymer-coated CuO NP was found to be more toxic than the uncoated CuO NP. The higher toxicity of CS-CuO NP was mainly associated with the increased capacity of polymer-coated CuO NP to penetrate the cell compared to bare CuO NPs. These results indicates that the high toxicity of polymer-coated CuO NPs in algal cells results of intracellular interactions between NPs and the cellular system.