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This paper reported antibiotic resistance and PFGE genetic typing of Streptococcus thermophilus stains isolated from different yogurt brands in Chinese market. In total, 42 strains isolated from 43 yogurt samples were identified as S. thermophilus stains by 16S rDNA sequence analysis. The investigation of antibiotic-resistance profiles revealed that those isolates were resistant to erythromycin (69.05 %), clindamycin (73.81 %), chloramphenicol (61.90 %) and fosfomycin (19.05 %), and were susceptible to other 13 kinds of antibiotics. The genetic typing of S. thermophilus stains was examined by pulsed-field gel electrophoresis (PFGE) of chromosomal DNA digested with SmaI. The enzyme restriction profiles showed the 42 S. thermophilus isolates were divided into 14 PFGE types, and further analysis showed the PFGE profile did not completely match with antibiotic resistance profile. The antibiotic resistance and PFGE pattern database generated in this study suggest that the safety evaluation of S. thermophilus should be paid more attention and will provide basic for information of food safe assessment of yogurt.

The effects of two different carbon sources on changes of catalase (CAT) yield, the values of antioxidant indexes and intermediate metabolites from Serratia marcescens SYBC08 were investigated at different time points (4, 8, 12, 16, 20 and 24 h). The highest CAT yield (20008 U‧mL-1) in presence of citric acid was approximately 1.46-fold higher than that in presence of glucose (13680 U‧mL-1). The maximum superoxide dismutase activity (21.53 U‧mL-1) was achieved in presence of citric acid, significantly higher than that in presence of glucose (15.20 U·mg-1protein). Intracellular alkyl hydroperoxide reductase activity in presence of citric acid or glucose was sharply increased during culture period and reached the maximum value at 24 h. Additionally, the NADH oxidase activities, total antioxidant capacities, intracellular and extracellular ascorbic acid contents, intracellular H2O2 level, malondialdehyde contents and intracellular contents of pyruvate, succinic acid and citric acid in presence of citric acid or glucose were also evaluated.

Collapse column water bursting occurs from time to time in the coal mining process of North China Type Coalfield in China, which causes great economic loss and personal injury. Therefore, great attention must be paid to the harm of collapse column. 1301 working face and 1306 working face in the west wing of No.1 Mining District of Zhangji Coal Mine in Shanxian County are close to No.2 collapse column. Water bursting risk evaluation must be carried out before mining two working faces to ensure safety production. On the basis of fully analyzing the geological and hydrogeological conditions of the 3up coal seam in the west wing of No.1 Mining Area, the "Three Zones(caving zone, water conducted fracture zone and sagging zone) Theory of Coal Seam Roof", "Strata Movement Theory" and "Water Bursting Coefficient Theory" were used respectively to calculate and evaluate the water bursting risk of No.2 collapse column during the course of mining the 1301 working face and 1306 working face. The results show that: firstly, in the process of mining the 1301 working face, the maximum height of the water conducted fracture zone at the closest position of 1301 working face to No.2 collapse column would be 60.20 m, the water bursting coefficient on the boundary of water conducted fracture zone would be 0.066~0.072 MPa/m, and the water bursting risk of the No.2 collapse column would be smaller; secondly, in the process of mining the 1306 working face, the maximum height of the water conducted fracture zone at the closest position of 1306 working face to No.2 collapse column would be 60.91 m, the water bursting coefficient on the boundary of water conducted fracture zone would be 0.057~0.089 MPa/m, and the water burst risk of the No.2 collapse column would be small. By August 31, 2020, the 1301 working face had been safely mined more than 200 meters long(exceeding over 120 m of the closest position in 1301 working face to No.2 collapse column), and the water bursting did not happen in the working face. This paper can provide a reference for the water prevention and control of similar collapse columns in coal mines.

The strong variations and uncertainties of high-penetration variable renewable energy sources (RESs) has greatly challenged the operation of power systems. Considering the rapid adjustability of hydropower to complement various RESs, in this paper, a coordinated optimization model is proposed for hydro-wind-solar integrated systems. Based on the variational auto-encoder, a scenarios generation method is proposed to capture the spatial-temporal complementary and fluctuant characteristics of wind and PV power with high model accuracy and low computational complexity. The detailed hydraulic and electrical relationship between cascade reservoirs are established to make full use of the controllable regulation capacity of cascade hydropower stations. With the linearization of the head-sensitive power generation and nonlinear water head, the optimization model is reformulated into a tractable mixed integer linear programming (MILP) formulation. A basin in Northwest China integrated with prolific wind and solar resources is selected for a case study. The computational experiments on actual data demonstrate the applicability of the proposed method.

The research activity on dispersed polymers – polymer particle size from tens of nanometers to hundreds of microns – carried out at ETH in our group is reviewed with a brief summary of the various projects currently in progress. These have been organized into two main categories: Polymer Reaction Engineering, where polymerization reaction and reactor operation and control are involved, and Colloidal Engineering, focused on the control of particle size distribution and development of special latex post-treatment processes, such as gelation.