On the comprehensive role of thermodynamic and kinetic factors in pyrolysis reaction systems

The present paper presents the view that, for complex reaction systems the Global Equilibrium Yield (GEY) could be exceeded by the observed yield. We define the Potentiel Maximum Equilibrium Yield (PMEY) which takes into account only the reversible reactions increasing the concentration of the desired product.The author has studied the reactions system of ethane pyrolysis and has calculated the maximum yield of ethylene. The GEY and the PMEY are respectively 5.6 x 10-6 and 0.9745 (in molar fraction) while the observed maximum yield is 0.669.The discussion deals with the comparative roles of thermodynamic and kinetic factors

Characterizing the antibiotic resistance genes in a river catchment: Influence of anthropogenic activities

Previous studies on environmental antibiotics resistance genes (ARGs) have focused on the pollution sources such as wastewater treatment plants, aquaculture and livestock farms, etc. Few of them had addressed this issue in a regional scale such as river catchment. Hence, the occurrence and abundances of 23 ARGs were investigated in surface water samples collected from 38 sites which located from the river source to estuary of the Beijiang River. Among them, 11 ARGs were frequently detected in this region and 5 ARGs sulII, tetB, tetC, and tetW) were selected for their distribution pattern analysis. The abundances of the selected ARGs were higher in the upstream (8.70 x 10(6) copies/ng DNA) and downstream areas (3.17 x 10(6) copies/ng DNA) than those in the midstream areas (1.23 x 10(6) copies/ng DNA), which was positively correlated to the population density and number of pollution sources. Pollution sources of ARGs along the Beijiang River not only had a great impact on the abundances and diversity, but also on the distribution of specific ARCs in the water samples. Both sulI and sulII were likely originated from aquaculture farms and animal farms, tetW gene was possibly associated with the mining/metal melting industry and the electric waste disposal and tetC gene was commonly found in the area with multiple pollution sources. However, the abundance of tetB was not particularly related to anthropogenic impacts. These findings highlight the influence of pollution sources and density of population on the distribution and dissemination of ARGs at a regional scale. (C) 2017 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V

MicroRNA-93 promotes the malignant phenotypes of human glioma cells and induces their chemoresistance to temozolomide

MicroRNAs (miRNAs), a class of small non-coding RNAs, can induce mRNA degradation or repress translation by binding to the 3′-untranslated region (UTR) of its target mRNA. Recently, some specific miRNAs, e.g. miR-93, have been found to be involved in pathological processes by targeting some oncogenes or tumor suppressors in glioma. However, the regulatory mechanism of miR-93 in the biological behaviors and chemoresistance of glioma cells remains unclear. In the present study, in situ hybridization and real-time RT-PCR data indicated that miR-93 was significantly upregulated in glioma patients (n=43) compared with normal brain tissues (n=8). Moreover, the upregulated miR-93 level was significantly associated with the advanced malignancy. We also found that upregulation of miR-93 promoted the proliferation, migration and invasion of glioma cells, and that miR-93 was involved in the regulation of cell cycle progression by mediating the protein levels of P21, P27, P53 and Cyclin D1. P21 was further identified as a direct target of miR-93. Knockdown of P21 attenuated the suppressive effects of miR-93 inhibition on cell cycle progression and colony formation. In addition, inhibition of miR-93 enhanced the chemosensitization of glioma cells to temozolomide (TMZ). Based on these above data, our study demonstrates that miR-93, upregulated in glioma, promotes the proliferation, cell cycle progression, migration and invasion of human glioma cells and suppresses their chemosensitivity to TMZ. Therefore, miR-93 may become a promising diagnostic marker and therapeutic target for glioma