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ADAR1 is a double-stranded RNA (dsRNA) editing enzyme that specifically converts adenosine to inosine. ADAR1 is ubiquitously expressed in eukaryotes and participate in various cellular processes such as differentiation, proliferation and immune responses. We report here a new proteomics study of HEK293T cells with and without ADAR1 overexpression. The up- and down-regulated proteins by ADAR1 overexpression are identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS) followed by label-free protein quantification. Totally 1,495 proteins (FDR < 0.01) are identified, among which 211 are up- and 159 are down-regulated for at least 1.5-fold (n = 3, p < 0.05). Gene ontology analysis reveals that these ADAR1-regulated proteins are involved in protein translation and cell cycle regulation. Bioinformatics analysis identifies a closely related network consistent for the protein translation machinery and a tightly connected network through proliferating cell nuclear antigen (PCNA)-interactions. Up-regulation of the proteins in the PCNA-mediated cell proliferation network is confirmed by Western blotting. In addition, ADAR1 overexpression is confirmed to increase cell proliferation in HEK293T cells and A549 cells. We conclude that ADAR1 overexpression modulates the protein translation and cell cycle networks through PCNA-mediated protein-protein interaction to promote cell proliferation in HEK293 cells.

Little attention has been paid to the histone H2A/K pseudogene. Results from our laboratory showed that 7 of 10 kidney cancer patients carried a mutant H2A/K pseudogene; therefore, we were interested in determining the relationship between mutant H2A/K and cell proliferation. We used shotgun and label-free proteomics methods to study whether mutant H2A/K lncRNAs affected cell proliferation. Quantitative proteomic analysis indicated that the expression of mutant H2A/K lncRNAs resulted in the upregulation of many oncogenes, which promoted cell proliferation. Further interaction analyses revealed that a proliferating cell nuclear antigen (PCNA)-protein interaction network, with PCNA in the center, contributes to cell proliferation in cells expressing the mutant H2A/K lncRNAs. Western blotting confirmed the critical upregulation of PCNA by mutant H2A/K lncRNA expression. Finally, the promotion of cell proliferation by mutant H2A/K lncRNAs (C290T, C228A and A45G) was confirmed using cell proliferation assays. Although we did not determine the exact mechanism by which the oncogenes were upregulated by the mutant H2A/K lncRNAs, we confirmed that the mutant H2A/K lncRNAs promoted cell proliferation by upregulating PCNA and other oncogenes. The hypothesis that cell proliferation is promoted by the mutant H2A/K lncRNAs was supported by the protein expression and cell proliferation assay results. Therefore, mutant H2A/K lncRNAs may be a new factor in renal carcinogenesis.

Zinc oxide nanoparticle is one of the most important materials with diverse applications. However, it has been reported that zinc oxide nanoparticles are toxic to organisms, and that oxidative stress is often hypothesized to be an important factor in cytotoxicity mediated by zinc oxide nanoparticles. Nevertheless, the mechanism of toxicity of zinc oxide nanoparticles has not been completely understood. In this study, we investigated the cytotoxic effect of zinc oxide nanoparticles and the possible molecular mechanism involved in calcium homeostasis mediated by plasma membrane calcium ATPase in rat retinal ganglion cells. Real-time cell electronic sensing assay showed that zinc oxide nanoparticles could exert cytotoxic effect on rat retinal ganglion cells in a concentration-dependent manner; flow cytometric analysis indicated that zinc oxide nanoparticles could lead to cell damage by inducing the overproduction of reactive oxygen species. Furthermore, zinc oxide nanoparticles could also apparently decrease the expression level and their activity of plasma membrane calcium ATPase, which finally disrupt the intracellular calcium homeostasis and result in cell death. Taken together, zinc oxide nanoparticles could apparently decrease the plasma membrane calcium ATPase expression, inhibit their activity, cause the elevated intracellular calcium ion level and disrupt the intracellular calcium homeostasis. Further, the disrupted calcium homeostasis will trigger mitochondrial dysfunction, generate excessive reactive oxygen species, and finally initiate cell death. Thus, the disrupted calcium homeostasis is involved in the zinc oxide nanoparticle-induced rat retinal ganglion cell death.

Ultraviolet B (UVB) could lead to the apoptosis of human lens epithelial cell and be hypothesized to be one of the important factors of cataractogenesis. In the human lens, Ca(2+)-ATPase is a major determinant of calcium homeostasis. Plasma membrane calcium ATPase1 (PMCA1) is a putative "housekeeping" isoform and is widely expressed in all tissues and cells, which plays an important role in calcium homeostasis. However, the effects of UVB-irradiation on the expression of PMCA1 and the cellular calcium homeostasis are still unclear. In the present study, we cultured human lens epithelial cells (HLE B-3) in vitro and investigated the effects of UVB irradiation on the expression of PMCA1 and the intracellular calcium homeostasis using real-time cell electronic sensing system, flow cytometry, fluo-3/AM probes, real-time quantitative PCR, and enzyme-linked immunosorbent assay techniques. We found that UVB irradiation could induce human lens epithelial cell death, cause intracellular calcium ion (Ca(2+)) elevation, inhibit Ca(2+)-ATPase activity and decrease the expression of PMCA1 at gene and protein levels, suggesting that the downregulation of PMCA1 and the disruption of calcium homeostasis may play important roles in UVB-induced HLE B-3 cell apoptosis.

Recent studies have proved that zinc oxide (ZnO) nanoparticles can cause toxicity in different cell lines, oxidative stress is often hypothesized to be an important factor in cytotoxicity of ZnO nanoparticles. However, the mechanisms are incompletely understood. The present study aimed to investigate the role of oxidative stress in toxicity and possible involvement of mitochondria in the production of reactive oxygen species (ROS) upon exposure of retinal ganglion cells (RGC-5) to ZnO nanoparticles. In this study, the effects of ZnO nanoparticles on mitochondrial membrane potential and ROS levels involved in hydrogen peroxide and hydroxyl radical production were investigated via inverted fluorescence microscope and hydrogen peroxide and hydroxyl radical assay kits, respectively. Furthermore, the mRNA of caspase-12 and the protein secreted into culture supernatant were also determined by means of real-time quantitative PCR and ELISA techniques. Our studies indicate that ZnO nanoparticles could apparently decrease the mitochondrial membrane potential, increase the production of ROS and lead to the overexpression of caspase-12 in RGC-5 cells, suggesting that ZnO nanoparticle-induced toxicity via ROS overproduction will trigger endoplasmic reticulum stress, lead to the RGC-5 cell damage and finally induce apoptosis/necrosis, the overexpression of caspase-12 may be involved in cell death in RGC-5 cells.

The reactive crystallization kinetics of hydromagnesite in the MgCl2-CO2-NH3-H2O system, which plays an important role in a new approach to sequester CO2 with saline sea/lake brines, was systematically investigated by the MSMPR (mixed-suspension-mixed-product removal) crystallization method. The temperature effect on the crystallization of magnesium carbonate hydrates in the system was first investigated batchwise. The optimum temperature of 353.2 K for precipitation of the regular spherical hydromagnesite with good filterability was selected for kinetic study. The supersaturation cf hydromagnesite was experimentally tested, and the activity coefficients of aqueous species were strictly calculated by the Pitzer model embedded in the Aspen Plus platform. The nucleation and growth rate and agglomeration kernel were determined by moments analysis based on the PSD (particle size distribution) of crystals in volume coordinates. The corresponding kinetic parameters in three empirical equations were then estimated by linear regression. The resulting volume growth rate order of 2.30 means that surface integration is dominant in the volume growth of hydromagnesite. A simplified process for the new sequestration approach was finally constructed. The value of hydromagnesite as carbonated product was assessed considering the scale-up and costs of such a process.

A chemical model, based on Pitzer activity coefficient model, is developed with a speciation approach to describe the solubility and chemistry of nesquehonite in concentrated chloride solutions. The chemical equilibrium constants for nesquehonite and aqueous species, i.e. MgCO30, MgHCO3+, and MgOH+, are precisely calculated as a function of temperature according to the Van't Hoff equation by use of standard Gibbs free energy, standard formation enthalpy and heat capacity. The most recent solubility data are regressed to obtain new Pitzer parameters with good agreement. The predictive ability of the new model is improved significantly in comparison with previous models. The behavior of speciation chemistry for nesquehonite in various chloride media is explained through this modeling work on the basis of the Mg/CO32- bearing species distribution, activity coefficient and pH changes.

Crystallization kinetics of ammonium carnallite (NH4MgCl3·6H2O), a double salt formed in NH4Cl-MgCl2 solution, and ammonium chloride in the NH4Cl-MgCl2-H2O system were experimentally investigated w...

A growth kinetic model has been developed from a rigorous thermodynamic perspective to describe the crystal growth rates of NH4Cl on the basis of the difference of chemical potentials of NH4Cl at solidliquid interface in aqueous NH4Cl, NH4Cl-NaCl, and NH4Cl-MgCl2 solutions. The solidliquid equilibrium and activity coefficient of NH4Cl are calculated by the newly developed accurate Pitzer model with aid of Aspen Plus(TM) platform. The predictions of the resulting model are in good agreement with the experimental data published in literature and determined in this work at 283.15333.15 K within the supersaturation up to 0.1. The kinetic model was subsequently used to analyze the effect of several operation variables, including temperature (283.15333.15 K), supersaturation (up to 0.1), and NaCl or MgCl2 concentration (0 similar to 2.5 mol kg-1), on the crystal growth rate of NH4Cl. The crystal growth rate of NH4Cl, with activation energy of 39 kJ mol-1, is strongly temperature-dependent and increases with increasing temperature in the three systems investigated. The advantage of MgCl2 over NaCl on the recovery of NH4Cl is theoretically and experimentally illustrated from the thermodynamic and kinetic perspectives with the aid of the established model. (c) 2011 American Institute of Chemical Engineers AIChE J, 2012

The results of work performed on reducing gypsum scale formation in transportation pipes of well salt brine are described. Two methods: seeding with calcium sulfate dihydrate and dilution of brine were proposed. With the first method, various mass and size distributions of seeds were introduced into an perspex reactor with well salt brine (NaCl: 300 g/L, Na(2)SO(4): 20 g/L) to investigate the factors that influence crystallization of calcium sulfate dihydrate, such as temperature, mass of seed crystals, and size distribution of seed crystals. The kinetics of calcium sulfate dihydrate growth at temperatures ranging between 5 and 25 degrees C were obtained. Results showed that the elimination of supersaturation was enhanced with increasing temperature and the dosage of seed crystal. It was also found that the more efficient in scale prevention was obtained when smaller seed crystals were employed. It was seen that the crystal growth of calcium sulfate dihydrate in brine was proportional to the square of supersaturation at the investigated temperatures. With the second method, results showed that a complete elimination of supersaturation was achieved when 4.3% water was added into the brine with the help of solubility determination of calcium sulfate dihydrate.

This work presents vapor pressure data for water, 1-propanol, and 2-propanol as well as their binary mixtures in the presence of ionic liquid (IL) 1,3-dimethylimidazolium dimethylphosphate ([MMIM][DMP]) at different temperatures and IL content ranging from mass fraction 0.10 to 0.70 using a quasi-static ebulliometer method. Activity coefficients of these solvents in the IL have been determined from the vapor pressure data of binary systems and correlated by the nonrandom two-liquid (NRTL) equation with an average relative deviation (ARD) within 0.013. The resulting binary NRTL parameters were used for the prediction of vapor pressure of ternary systems with fair accuracy. Furthermore, the isobaric vapor-liquid equilibrium data for ternary systems water + 1-propanol + [MMIM][DMP] and water + 2-propanol + [MMIM][DMP] at different IL mass fractions were predicted. It is shown that the relative volatility of 1-propanol and 2-propanol is enhanced and that the azeotrope of water + 1-propanol and water + 2-propanol mixtures is eliminated completely.

A new method to recover NH4Cl from NH4Cl-rich aqueous solutions generated in the magnesia (MgO) production is developed on the basis of modeling the solid-liquid equilibrium (SLE) for the NH4Cl-MgCl2-H2O system with the Pitzer model embedded in Aspen Plus (TM) platform. The SLE values for the ternary system were determined from 278.15 to 348.15 K. The new standard-state chemical potentials of NH4Cl and MgCl2 center dot 6H(2)O were judicially obtained. The resulting equilibrium constants were used to determine new interaction parameters for the NH4Cl-H2O and MgCl2-H2O systems. These new parameters, together with the mixing parameters determined from correlating the experimental values, were used to correlate the equilibrium constant for NH4MgCl3 center dot 6H(2)O, which plays a key role in NH4Cl recovery. The results could extend SLE calculation for the NH4Cl-MgCl2-H2O system from 278.15 to 388.15 K, satisfying the process identification and simulation requirement involved in the recovery process. The phase-equilibrium diagram generated by modeling was illustrated to identify the process alternatives for recovering NH4Cl. The resulting course to recover NH4Cl by three fractional crystallization operations was finally proved feasible. (C) 2010 American Institute of Chemical Engineers AIChE J, 57: 1595-1606, 2011

Currently, titanium dioxide nanoparticles (TiO2 NPs) have been widely used in various applications including cosmetics, food additives and biomedicine. However, there are few reports available using TiO2 NPs to treat ocular diseases. Posterior capsular opacification (PCO) is the most frequent complication after cataract surgery, which is induced by the proliferation and migration of lens epithelial cells. Thus, inhibiting the proliferation of lens epithelial cells will efficiently reduce the occurrence of PCO. In this study, we investigated the effects of TiO2 NPs on HLE B-3 cells with or without ultraviolet B (UVB) irradiation in vitro. We found that TiO2 NPs can inhibit HLE B-3 cell growth, cause the elevation of intracellular [Ca(2+)], produce excessive reactive oxygen species (ROS), further reduce Ca(2+)-ATPase activity and decrease the expression of plasma membrane calcium ATPase 1 (PMCA1), finally disrupt the intracellular calcium homeostasis and induce cell damage. Importantly, UVB irradiation can apparently enhance these effects on HLE B-3 cells in the presence of TiO2 NPs. Taken together, the generation of excessive ROS and the disruption of intracellular calcium homeostasis may be both involved in TiO2 nanoparticle-induced HLE B-3 cell damage under UVB irradiation.

Nanomaterials, including zinc oxide (ZnO) nanoparticles, are being developed for a variety of commercial products. Recent reports showed that cells exposed to ZnO nanoparticles produced severe cytotoxicity accompanied by oxidative stress and genotoxicity. To understand the possible mechanism underlying oxidative stress of ZnO nanoparticles, the present investigation focused on the direct bioactivity of ZnO nanoparticles using a rat retinal ganglion cell (RGC-5) culture. At concentrations relevant to those used in vitro exposure of RGC-5 cells to ZnO nanoparticles, it was found that ZnO nanoparticles could inhibit cell proliferation in time- and concentration-dependent manners. Meanwhile, cell cycle arrest of S and G2/M phases occurred in RGC-5 cells induced by ZnO nanoparticles. Moreover, our results also demonstrated that the overproduction of reactive oxygen species (ROS) and elevated level of caspase-12 as well as decreased levels of bcl-2 and caspase-9 occurred after treatment with different concentrations of ZnO nanoparticles when compared to those in untreated cells. In summary, our findings suggest that ZnO nanoparticles could lead to the over generations of ROS and caspase-12 as well as decreased levels of bcl-2 and caspase-9. These results indicate that bcl-2, caspase-9 and caspase-12 may play significant roles in ZnO nanoparticle-induced RGC-5 cell damage.

By using a neuron-like map model to denote the generic dynamics of excitable systems, Gaussian-noise-induced pattern formation in the two-dimensional coupled map lattices with nearest-neighbor coupling and shortcut links has been studied. Given the appropriate initial values and parameter regions, with all nodes concerned, the functions of δ(n), χ and ℜ are introduced to analyze the evolution of pattern formation. It is found that there exists a critical εc beyond which the stable rotating spiral wave will appear. After introducing the Gaussian noise for the homogeneous ε region, different spatiotemporal stable patterns will be achieved. Additionally, the importance of the parameter I on the coupling strength C is discussed.