Determination of non-ionic surfactants and their biotransformation by-products adsorbed on alive activated sludge

A procedure has been developed for the determination of non-ionic surfactants (NS) adsorbed on particles of alive and dead activated sludge. The procedure also enables the determination of adsorption of major biodegradation by-products: short-chained ethoxylates, long- and short-chained PEG. The basis of measurement is the determination of NS concentration in a slurry of activated sludge and in a solution phase. The difference between these two concentrations represents the NS adsorbed on activated sludge. Separation of NS and their biotransformation by-products from samples and then on narrower fractions was performed by a sequential liquid-liquid extraction and precipitation with modified Dragendorff reagent. The indirect tensammetric technique (ITT) was applied for the final determination. The developed method was checked using the example of the treatment of the surfactant C12E10 (oxyethylated fatty alcohol) (C12E10) in the continuous flow activated sludge facility. No statistically significant accumulation of C12E10 on the alive activated sludge was detected, probably because of faster C12E10 fission than its adsorption. However, significant adsorption of the short-chained ethoxylates (including free alcohol) on the alive activated sludge was found, as well as statistically significant adsorption of long- and short-chained PEG. The adsorption of surfactant C12E10 and its biodegradation by-products on dead activated sludge was found to be higher than the species adsorption on alive activated sludge.     

A Combined Metabolomic and Proteomic Analysis of Gestational Diabetes Mellitus

The aim of this pilot study was to apply a novel combined metabolomic and proteomic approach in analysis of gestational diabetes mellitus. The investigation was performed with plasma samples derived from pregnant women with diagnosed gestational diabetes mellitus (n = 18) and a matched control group (n = 13). The mass spectrometry-based analyses allowed to determine 42 free amino acids and low molecular-weight peptide profiles. Different expressions of several peptides and altered amino acid profiles were observed in the analyzed groups. The combination of proteomic and metabolomic data allowed obtaining the model with a high discriminatory power, where amino acids ethanolamine, l-citrulline, l-asparagine, and peptide ions with m/z 1488.59; 4111.89 and 2913.15 had the highest contribution to the model. The sensitivity (94.44%) and specificity (84.62%), as well as the total group membership classification value (90.32%) calculated from the post hoc classification matrix of a joint model were the highest when compared with a single analysis of either amino acid levels or peptide ion intensities. The obtained results indicated a high potential of integration of proteomic and metabolomics analysis regardless the sample size. This promising approach together with clinical evaluation of the subjects can also be used in the study of other diseases.     

正交各向异性损伤材料的Mohr-Coulomb条件

提出了正交异性损伤修正的Mohr-Coulomb条件，从对含裂纹单元的细观分析入手，通过均匀化（Homogenization)处理，将损伤张量引入到Mohr-Coulomb条件中，推导出相应的计算公式，采用的损伤模型考虑了裂纹的闭合效应，得出了新条件在二维层状岩石体中的简单应用，按本文提出的损伤材料的Mohr-Coulomb条件，计算得到了层状节理岩体侧压力－剪切强度曲线，结果的非线性特性与文献中的试验结果吻合，说明传统的侧压力与剪切强度的关系（试验中所获得的剪切强度值只是与过程有关的参数c,而不是材料参数c^t)。