Evaluation of Corrosion Protection Performance of New Polymer Composite Coatings on Carbon Steel in Acid Medium by Electrodeposition Methods

In this research, electrodeposition procedure was utilized for the synthesis of a new composite polymer: N-methylpyrrole–Triton–X100/N, N, N-diethylaniline (NMpy-TRx100/NNDEA) used as a coating on carbon steel type OL 37 electrode for corrosion protection. The surfactant Triton–X100, a dopant ion utilized throughout the process of electropolymerization, had a significant impact on the corrosion protection of this composite by impeding the penetration of corrosive ions. PNMpy-TRx100/PNNDEA coatings were successfully realized on the OL37 substrate by a galvanostatic method of synthesis using the solutions 0.1 M NNDEA, 0.1 M MPY, 0.03 M TRX-100, and 0.3 M H2C2O4, at varied current densities (3 mA/cm2, 5 mA/cm2 and 8 mA/cm2) in different molar ratios (1:1, 1:5, 3:2 and 5:1). The deposition was performed for 20 and 30 min. The polymeric composite coatings were characterized electrochemically, spectroscopically, and morphologically by cyclic voltammetry, Fourier transform infrared spectroscopy, and scanning electron microscopy methods. Corrosion protection performance of PNMpy-TRx100/PNNDEA-coated OL 37 was examined through potentiostatic and potentiodynamic polarization, open circuit potential measurements, and electrochemical impedance spectroscopy procedures in 0.5 M H2SO4 media. The corrosion rate of PNPMpy-TRx100/PNNDEA-coated OL 37 was denoted to be around nine times less than that of an uncoated electrode. The corrosion protection yield of the coating was more than 90%. The best effectiveness was realized for PNMPY-TRX-100/PNNDEA by electrodeposition at 5 mA/cm2 current density applied in molar ratios of 5:1 and 3:2, and at 8 mA/cm2 current densities applied in molar ratio 5:1. The outcomes of the corrosion experiments revealed that PNMPY-TRX-100/PNNDEA coatings provide a good anticorrosion protection of OL 37 in corrosive solutions.

Inactivation of Material from SARS-CoV-2-Infected Primary Airway Epithelial Cell Cultures

Given that the airway epithelium is the initial site of infection, study of primary human airway epithelial cells (AEC) infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) will be crucial to improved understanding of viral entry factors and innate immune responses to the virus. Centers for Disease Control and Prevention (CDC) guidance recommends work with live SARS-CoV-2 in cell culture be conducted in a Biosafety Level 3 (BSL-3) laboratory. To facilitate downstream assays of materials from experiments there is a need for validated protocols for SARS-CoV-2 inactivation to facilitate safe transfer of material out of a BSL-3 laboratory. We propagated stocks of SARS-CoV-2, then evaluated the effectiveness of heat (65 °C) or ultraviolet (UV) light inactivation. We infected differentiated human primary AECs with SARS-CoV-2, then tested protocols designed to inactivate SARS-CoV-2 in supernatant, protein isolate, RNA, and cells fixed for immunohistochemistry by exposing Vero E6 cells to materials isolated/treated using these protocols. Heating to 65 °C for 10 min or exposing to UV light fully inactivated SARS-CoV-2. Furthermore, we found in SARS-CoV-2-infected primary AEC cultures that treatment of supernatant with UV light, isolation of RNA with Trizol®, isolation of protein using a protocol including sodium dodecyl sulfate (SDS) 0.1% and Triton X100 1%, and fixation of AECs using 10% formalin and Triton X100 1%, each fully inactivated SARS-CoV-2.

Molecular Interactions in Binary Surfactant Solutions: Effect of Ionic Counterpart

The effect of intermolecular interactions on processes of micelle formation and adsorption in binary mixtures of non-ionic Triton X100 (TX100) with ionic sodium dodecyl sulfate and dodecylpyridinium bromide surfactants was studied. The ionic surfactants have identical hydrophobic alkyl chain and different hydrophilic groups. A feature of the used binary surfactant mixtures is that critical micelle concentrations and surface activity of the individual components are considerably different. A synergetic effect of decreasing of the surface tension was found in the surfactant mixtures. It was shown that the mixed adsorption layers and the micellar phases are enriched with the nonionic surfactant. For both sodium dodecyl sulfate/TX100 and dodecylpyridinium bromide/TX100 systems, the synergetic effects were most pronounced at a high molar fraction of the nonionic surfactants in the mixture. By using the Ruben-Rosen model, molecular interaction parameters in the mixed micelles βm, and in the adsorption layers βσ were evaluated. As was shown βm and βσ parameters to be notably higher for sodium dodecyl sulfate/TX100 mixture. Resumen. Se estudia el efecto de las interacciones intermoleculares en el proceso de formación y adsorción de micelas en mezclas binarias de Triton X100 (TX100), no iónico, con dodecil sufato de sodio y bromuro de dodecil piridinio, ambos iónicos, como surfactantes. Los surfactantes iónicos tienen cadenas alquílicas hidrofóbicas idénticas y grupos hidrofílicos diferentes. Una característica de las mezclas binarias de surfactantes que se utilizaron es que las concentraciones micelares críticas y la actividad superficial de los componentes individuales es considerablemente diferente. Se encontró un efecto sinérgico de decremento de la tensión superficial en las mezclas de surfactantes. Se muestra que las capas mixtas de adsorción y las fases micelares están enriquecidas con surfactante no iónico. Tanto en el sistema dodecil sufato de sodio/TX100 como en el caso de bromuro de dodecil piridinio/TX100, los efectos sinérgicos fueron más pronunciados en las mezclas con fracciones molares altas de los surfactantes no iónicos. Utilizando el modelo de Ruben-Rosen, se evaluaron los parámetros de interacción molecular en las micelas mezcladas βm y en las capas de adsorción βσ. Se muestra que los parámteros βm son βσ son notablemente mayores en la mezcla de dodecil sufato de sodio/TX100.

Identification and Characterization of the Entamoeba Histolytica Rab8a Binding Protein: A Cdc50 Homolog

Membrane traffic plays a pivotal role in virulence in the enteric protozoan parasite Entamoeba histolytica. EhRab8A small GTPase is a key regulator of membrane traffic at the endoplasmic reticulum (ER) of this protist and is involved in the transport of plasma membrane proteins. Here we identified the binding proteins of EhRab8A. The Cdc50 homolog, a non-catalytic subunit of lipid flippase, was identified as an EhRab8A binding protein candidate by affinity coimmunoprecipitation. Binding of EhRab8A to EhCdc50 was also confirmed by reciprocal immunoprecipitation and blue-native polyacrylamide gel electrophoresis, the latter of which revealed an 87 kDa complex. Indirect immunofluorescence imaging with and without Triton X100 showed that endogenous EhCdc50 localized on the surface in the absence of permeabilizing agent but was observed on the intracellular structures and overlapped with the ER marker Bip when Triton X100 was used. Overexpression of N-terminal HA-tagged EhCdc50 impaired its translocation to the plasma membrane and caused its accumulation in the ER. As reported previously in other organisms, overexpression and accumulation of Cdc50 in the ER likely inhibited surface transport and function of the plasma membrane lipid flippase P4-ATPase. Interestingly, HA-EhCdc50-expressing trophozoites gained resistance to miltefosine, which is consistent with the prediction that HA-EhCdc50 overexpression caused its accumulation in the ER and mislocalization of the unidentified lipid flippase. Similarly, EhRab8A gene silenced trophozoites showed increased resistance to miltefosine, supporting EhRab8A-dependent transport of EhCdc50. This study demonstrated for the first time that EhRab8A mediates the transport of EhCdc50 and lipid flippase P4-ATPase from the ER to the plasma membrane.

Mixed Adsorption of Cetyltrimethylammonium Bromide and Triton X-100 Surfactants on Carbon Black

Adsorption of cationic cetyltrimethylammonium bromide (CTAB) and nonionic Triton X100 surfactants from their mixed aqueous solutions on graphitized carbon black (CB) have been studied. The adsorption isotherms of CTAB or Triton X100 from single solutions on CB surface shown to be of the Langmuir type. In the mixed solutions of CTAB and Triton X100 surfactants, the adsorption of CTAB or Triton X100 on CB decreased in the presence of the other surfactant due to competitive adsorption of the components. It was shown that the mole fraction of Triton X-100 on CB surface has been essentialy changed depending on total concentration of the surfactants mixture. At mixture concentration corresponding to the unsaturated monolayer, a strong synergetic effect was found when the surface excess concentration Triton X100 at the CB surface in the presence of CTAB is higher than that for Triton X-100 in the absence of CTAB.