Drying-Induced Hierarchical Dimple Patterns on Partially Miscible Polymeric Films Under Ordered Convections

We describe the formation of hierarchical dual dimple patterns on polymeric sublayers by evaporation-induced interfacial stress. As water vapor condenses on partially miscible volatile sublayers, the resulting unstable wet-on-wet configurations trigger droplet assembly under ordered convection, giving rise to hexagonal traces of surface dimples, which coexist with highly ordered dimple arrays. Monitoring the time-dependent Marangoni numbers proved that the interfacial stress plays a crucial role in the transition between hierarchically and uniformly ordered dimple patterns.     

Particle Transport at Low Pressure: Deposition in Bends of a Circular Cross-Section

Particle inertial loss in bends of a circular cross section was studied experimentally in a low-pressure environment down to 0.2 Torr. Uniform aerosols across the bend inlets were produced by a new method developed by Sato et al. (2002a). The deposition efficiency was obtained by measuring the mass of deposited ammonium fluorescein particles with a fluorometer. The ranges of the Dean number and the curvature ratio (the ratio of the radius of curvature to the tube radius) were 1.8-2.2 and 3.6-4.7, respectively. The flow Reynolds number varied from 3.4 to 4.8. The results agreed with the general trend shown numerically by Tsai and Pui (1990), i.e., the deposition efficiency increases with increasing Stokes number and Dean number, and with decreasing curvature ratio. However, the experimental Stk 50 --the Stokes number at 50% deposition efficiency--was larger than that predicted by Tsai and Pui's empirical equation. The difference was attributed to the fact that their equation was obtained using the results for Dean numbers ranging from 38 to 869 and thus failed to predict the Stk 50 for a smaller Dean number. A new analytical equation for Stk 50 as a function of the Dean number and the curvature ratio was obtained. The proposed new equation can be used to calculate the Stk 50 for Dean numbers near unity.     

Influence of disinfection on bacterial regrowth in pilot distribution system

A correlation between heterotrophic plate count (HPC) and chloramine residual in pilot distribution systems (PDSs) was investigated. The data was derived from an AWWARF (the Awwa Research Foundation) and Tampa Bay Water tailored collaboration project to determine the effect of blending different waters on distribution system water quality. Seven different finished waters were produced from surface, ground, or simulated brackish water sources on site and fed to 18 independent PDSs, either as a single finished water or as a blend of several finished waters. Significantly higher numbers for PDS HPC were observed below 0.06 mg/L of combined chlorine residual. Changes in assimilable organic carbon (AOC) levels between influent and effluent of the PDSs increased as disinfectant dosage decreased in distribution systems. Significant differences between input and output AOC (ΔAOC) were observed when the chloramine residual was less than 1.0 mg/L, and particularly when less than 0.5 mg/L. High HPC counts often occurred when chloramine residual was less than 0.5 mg/L, regardless of AOC levels or AOC stability. However AOC instability could occur at high influent AOC levels even in the presence of residual greater than 0.5 mg/L, with corresponding high HPC counts.     

利用固体废弃物制备干粉砂浆的应用研究

用矿渣、粉煤灰等固体废弃物为主要原材料,制备性能满足GB175-2007标准要求的生态型胶凝材料,代替425#普通硅酸盐水泥;利用矿山尾矿部分代替河砂,添加以改性膨润土为主的保水增稠剂,成功开发了系列干粉砂浆产品。固体废弃物利用率高达70%～90%,各项性能指标符合标准DBJ/T01-73-2003《干拌砂浆应用技术规程》的要求。     

Uromodulin Regulates Murine Aquaporin−2 Activity via Thick Ascending Limb–Collecting Duct Cross−Talk during Water Deprivation

Uromodulin, a urinary protein synthesized and secreted from the thick ascending limb (TAL) of the loop of Henle, is associated with hypertension through the activation of sodium reabsorption in the TAL. Uromodulin is a potential target for hypertension treatment via natriuresis. However, its biological function in epithelial cells of the distal nephron segment, particularly the collecting duct, remains unknown. Herein, we examined the regulation of uromodulin production during water deprivation in vivo as well as the effect of uromodulin on the activity of the water channel aquaporin−2 (AQP2) in vitro and in vivo using transgenic mice. Water deprivation upregulated uromodulin production; immunofluorescence experiments revealed uromodulin adhesion on the apical surface of the collecting duct. Furthermore, the activation of AQP2 was attenuated in mice lacking uromodulin. Uromodulin enhanced the phosphorylation and apical trafficking of AQP2 in mouse collecting duct cells treated with the vasopressin analog dDAVP. The uromodulin-induced apical trafficking of AQP2 was attenuated via endocytosis inhibitor treatment, suggesting that uromodulin activates AQP2 through the suppression of endocytosis. This study provides novel insights into the cross−talk between TAL and the collecting duct, and indicates that the modulation of uromodulin is a promising approach for diuresis and hypertension treatment.