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The assistances of sodium dodecyl benzene sulfonate (SDBS) and aging treatment were introduced to further improve the room-temperature mechanochemical synthesis of the quantum-sized zinc sulfide (ZnS) nanocrystals. As a result, a green strategy for synthesizing the monodisperse nanocrystals with tunable size and crystallinity was developed, holding convenient, highly efficient and low pollution. Size evolution shows a gradually increasing trend along the aging-temperature. A model that the independent reaction cells constructed by SDBS-wrapped reactant packages (solid state vesicles, SSVs) for the confined growth of ZnS nanocrystals was proposed to access the formation mechanism of ZnS quantized crystal in a solid-state synthesis system. The band gaps and band-edge luminescent emissions of as-prepared ZnS nanocrystals experienced the size-dependent quantum confinement effect, while the trap-state emissions exhibited the lattice integrity-dependence. Furthermore, ZnS quantum-sized nanocrystals with narrower size distribution can be obtained by a batch-sorting process through adjusting the centrifugal speed.

Fluid shear stress plays an important role in bone osteogenic differentiation. It is traditionally believed that pulsed and continuous stress load is more favorable for fracture recovery and bone homeostasis. However, according to our clinical practice, we notice that one single stress load is also sufficient to trigger osteogenic differentiation. In the present study, we subject osteoblast MC3T3-E1 cells to single bout short duration fluid shear stress by using a parallel plate flow system. The results show that 1 hour of fluid shear stress at 12 dyn/cm(2) promotes terminal osteogenic differentiation, including rearrangement of F-actin stress fiber, up-regulation of osteogenic genes expression, elevation of alkaline phosphatase activity, secretion of type I collagen and osteoid nodule formation. Moreover, collaboration of BMP2 and integrin β1 pathways plays a significant role in such differentiation processes. Our findings provide further experimental evidence to support the notion that single bout short duration fluid shear stress can promote osteogenic differentiation.

It is of great significance to study the main control factors of erosion and water inrush from the confined water guiding column of coal mine floor to reveal the water inrush mechanism of the Karst collapse column and to guide its water inrush prevention. The mechanical model of erosion and water inrush of collapse column is established, the multi-physics coupling software COMSOL Multiphysics is used to numeralize the model. The non-uniform distribution characteristics of the cracks in the collapse column are considered to perform the simulation research for the whole process of water inrush of collapse column under erosion action, and the influence of water pressure, initial fracture distribution and fracture development degree on water inrush of collapse column are analyzed. The results show that the greater the aquifer water pressure and the initial fissure opening is, the faster the water inflow from the collapse column increases and the greater the risk of water inrush is. The initial fracture distribution mainly affects the distribution of the final water inrush channel, and has little effect on the water inrush time and water inflow. Under the action of hydraulic erosion of confined aquifer, the filling particles in the collapse column liquefy and migrate away, and some cracks continue to increase and penetrate and develop into several superior water guiding channels, which ultimately causes the sudden increase of water inflow in collapse column and the occurrence of water inrush accidents.

To quantify the emission of airborne actinomycetes from the wastewater treatment plant (WWTP), the concentration and size distribution of airborne culturable actinomycetes were examined with a six-stage cascade impactor in a municipal WWTP with oxidation ditch process in Xi'an, China from June to July 2011. Simultaneously, characteristics of airborne bacteria were also measured to compare with data of actinomycetes. Similar to airborne bacteria, the concentration and size distribution of airborne actinomycetes were found to vary greatly at different phases of the wastewater treatment process. The mean concentration of actinomycetes in the WWTP ranged from 2139±229 at the sludge dewatering house (SDH) to 902±54 CFU·m-3 at the effluent outlet (EO). The largest emission source of actinomycete aerosols was detected at the SDH, with 21-fold exceeding the permissible standards recommended in the literature. The particle size distributions showed that similar single-peak distribution patterns appeared for both airborne actinomycetes and bacteria. The count median diameter (CMD) of total actinomycetes and bacteria concentration were 2.3 and 3.2 µm in the WWTP, respectively. Although the total concentration of actinomycetes was smaller than that of bacteria in the present WWTP, the respirable fraction (particles smaller than 4.7 µm in aerodynamic diameter) for actinomycetes (81.9%) was higher than that for bacteria (64.6%). The results obtained in the present research suggest that more attention should be paid to the potential health risk related to actinomycetes in studies on wastewater treatments. [ABSTRACT FROM AUTHOR]