112,110 research outputs found
Effects of environmental and electric perturbations on the pKa of thioredoxin cysteine 35: a computational study
No full textHere we present a theoretical-computational study dealing with the evaluation of the pKa of the Cysteine residues in Thioredoxin (TRX) and in its complex with the Thioredoxin-interacting protein (TXNIP). The free energy differences between the anionic and neutral form of the Cysteine 32 and 35 have been evaluated by means of the Perturbed Matrix Method with classical perturbations due to both the environment and an exogenous electric field as provided by Molecular Dynamics (MD) simulations. The evaluation of the free energies allowed us to show that the effect of the perturbing terms is to lower the pKa of Cysteine 32 and Cysteine 35 with respect to the free amino-acid. On the other hand, in the complex TRX-TXNIP, our data show an enhanced stabilization of the neutral reduced form of Cys 35. These results suggest that external electric stimuli higher than 0.02 V/nm can modulate the Cysteine pKa, which can be connected to the tight regulation of the TRX acting as an antioxidant agent
Atmospheric pressure plasma treatment of polyurethane foams for heavy metals removal from water
No full textauthor-bios-SRD-19-0063.R1 – Supplemental material for The Network Structure of Police Misconduct
No full textSupplemental material, author-bios-SRD-19-0063.R1 for The Network Structure of Police Misconduct by George Wood, Daria Roithmayr and Andrew V. Papachristos in Socius</p
Hybrid perfluorocarbon/carboxylic acid thin films via plasma deposition of hexafluoropropene and acrylic acid mixtures
No full textPolymeric films containing hydrophilic and hydrophobic functionalities are of interest for several applications, from biomaterials to fuel cells. In this study, we report on the plasma copolymerization of hexafluoropropene - acrylic acid mixtures. By finely tuning the monomers’ ratio and the plasma power, it is possible to adjust the relative amount of the hydrophilic and hydrophobic functionalities in the deposited films. Correspondingly, the wetting behavior can be tuned from fully hydrophilic to hydrophobic. Finally, depending on the process parameters, film proton conductivities in the range 20–70 mS cm−1 are obtained
Validation of colorimetric assays for hydrogen peroxide, nitrate and nitrite ions in complex plasma-treated water solutions
No full textLiquids treated with cold plasma emerged as ‘redox drugs’ in biomedicine, as sources of reactive oxygen and nitrogen species targeting cellular functions, including wound healing and cancer progression. The use of cell culture media as starting liquid, however, challenges the identification of plasma-generated chemistry, limited by the presence of many reactive species and organic compounds. Available detection methods need, therefore, to be confirmed in these liquids to avoid inaccurate results. In this research, robustness, linearity, accuracy and specificity of three colorimetric assays are investigated to detect H2O2, NO2− and NO3−, predominant plasma-induced products. The results clearly highlight the presence of some factors affecting the detection in cell culture media like high concentrations of chlorides found interfering with the detection of NO3− in the medium
The active role of organic molecules in the formation of long-lived reactive oxygen and nitrogen species in plasma-treated water solutions
No full textPlasma-treated water solutions (PTWS) allow the delivery of reactive oxygen and nitrogen species (RONS) to cells and tissues for different purposes. The mechanism of RONS formation has been clearly modelled in simple liquids like water, by assuming a plasma-driven process independent from the liquid. PTWS for biological experiments, however, are often produced from solutions of complex composition, where the formation mechanism of RONS is far from being understood. In this paper, we describe how water, phosphate-buffered saline solution and two cell culture media were plasma-treated in different conditions to demonstrate how the different composition of the liquids affects the formation of stable RONS (H2O2 and NO2−) in the resulting PTWS, especially when aromatic organic molecules are present
Deposition of thin films containing carboxylic acid groups on polyurethane foams by atmospheric pressure non-equilibrium plasma jet
No full textThin films containing carboxylic acid groups are deposited on open-cell polyurethane (PU) foams by using an atmospheric pressure non-equilibrium plasma jet, in dielectric barrier discharge configuration, fed with helium, acrylic acid and ethylene. The arrangement of the plasma jet, the sample holder, and the substrate is carefully optimized to enable the penetration of the plasma ejected from the remote source throughout the three-dimensional (3D) porous structure of the foam, and, therefore, to achieve the uniform coverage of the entire substrate. X-ray photoelectron spectroscopy analyses and scanning electron microscopy observations confirm that both the outer and the inner surfaces of the foam can be functionalized with the plasma-deposited coating, showing moderate changes in surface chemical composition and coating thickness moving from the exterior to the interior of the plasma-treated samples. The ability of the foams to adsorb heavy metals from water is tested through evaluation of cadmium ions (Cd2+) removal. The foams adsorption capacity can increase more than 10 times after plasma deposition and remains unchanged over 8 adsorption-release cycles
Applicazioni di reti neurali artificiali per l'identificazione delle condizioni di assetto standard di reti elettriche di media tensione
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