Simple N Compounds Electrochemical Behavior of Steel in Aqueous Solutions

Chemical polishing or electropolishing, instead of mechanical polishing, are recommended for the attainment of metallic surface polishes without the introduction of contaminates or tensions in the surface layers of the metal. The fundamental difference between the chemical and electropolishing processes is that in the latter anodic currents/potentials are used to help in the dissolution and passivation of the metal. The elctropolishing process inhibited with different ratio by addition of amide derivatives with concentration range 1x10-6 to 5x10-3M .The results reveal that amides have strongest inhibitive effect ranging from 4 to 38 %.  Thermodynamic parameters as well as adsorption isotherms were driven. Keywords: Electropolishing, amide derivatives Thermodynamic parameters, adsorptio

Oxide Film Growth on Copper in Neutral Aqueous Solutions

The copper electrode potentials measured by the open circuit potential method in strongly aerated solutions of SO4-2, Cl-, Br-, I-, CrO4-2, CO3-2, and NO2- with difference concentrations, till steady state values are attained. The copper electrode potentials of the all experiments increase from negative to more positive values indicating oxide film growth. The copper oxide film thickness attains maximum value at low and high concentrations of each aggressive and inhibitive anions respectively. The rate of oxide film thickening is determined by use the relation: E = a + b log t, where a and b are constants. The concentration of the inhibitive anions, CrO4-2, CO3-2, and NO2- that can withstand a certain concentration of the aggressive ions, , Cl-, Br-, and I-, varies due to the relation: logC inh. = A + n logC agg., where A and n are constants. The all experiments were investigated at 25oC in all electrolytes. Keywords: Copper; oxide growth; passivity; open circuit potential

Inhibitive Effect of Urea and Urea Derivatives on the Corrosion of Silver in Acetic Acid Solutions

The corrosion of silver in acetic acid was studied using potentiodynamic polarization technique in absence and presence of different concentrations of urea, thiourea and N-allylthiourea. The inhibition efficiency was found to depend on both the inhibitor type and concentration. The inhibitive action of these compounds is based on the formation of salt complex and/or the adsorption of the protonated species on the metal surface according to Temkin's isotherm. The thermodynamic parameters Kads and ΔG°ads for the adsorption process are calculated and discussed

Investigation of Inhibition Effect of Acrylic acid on C-Steel Corrosion in Sulfuric Acid Solutions

Acrylic acid was tested as a corrosion inhibitor for C-steel in 0.5 M H2SO4 using gasometry, weight loss, and galvanostatic polarization techniques. Polymeric film is built up by cyclic voltammetry technique. The potentiodynamic polarization is used to examine the inhibition effect with the coated polymeric film. The data obtained from the different techniques coincide in that acrylic acid is a good mixed-type inhibitor. The inhibition process is based on the adsorption of acrylic acid on the surface of C-steel according to Temkin’s adsorption isotherm. The inhibition efficiency increases with inhibitor concentration and decreases with temperature. The thermodynamic parameters ΔE, ΔH*, ΔS*, and ΔG*ads were calculated to elaborate the mechanism of corrosion inhibition

Ceftriaxone as an Inhibitor for Corrosion of Al in Formic Acid Solutions

The inhibiting effect of ceftriaxone on the corrosion of Al in HCOOH solution was studied by means of weight loss, thermometry, hydrogen evolution and potentiodynamic polarization techniques, complemented with surface examination using scanning electron microscopy (SEM). The obtained results showed that ceftriaxone are excellent inhibitor in HCOOH solution. The inhibition efficiency increases with inhibitor concentration. Polarization curves indicate that ceftriaxone was acted as a mixed-type inhibitor. The adsorption of the inhibitor on Al surface was found to obey Langmuir isotherm and showed a physisorption mechanism. The thermodynamic activation and adsorption parameters were calculated and discussed. Keywords: Ceftriaxone, aluminum, corrosion inhibitor, potentiodynamic polarization, adsorption, gravimetry and gasometr

Oxide Film Destruction on Al-Mg Alloys in HCl Solutions

Open circuit potential technique is used to follow the oxide film destruction of three of Al-Mg alloys in HCl solutions of varying concentrations.  Dissolution of the passive film on pare metal surface takes place in two distinct steps indicating that the film is composed mainly of a barrier layer of Al2O3 adjacent to the metal surface and an outer porous modification on the top of the first one. The rates of oxide film destruction and/or dissolution (δ1¯ and δ2¯) follow a direct logarithmic law. The extent of oxide film destruction and metal dissolution were found to increase with increasing the acid concentration and the percent of Mg content in the alloy sample

Inhibition effect of famotidine towards the corrosion of C-steel in sulphuric acid Solution

The inhibition effect of  famotidine drug  towards  the corrosion of C-steel in 0.5M H2SO4 was studied using weight loss, gasometry, potentiodynamic polarization and electrochemical frequency modulation (EFM) techniques, as well as, surface examination by SEM. The inhibition mechanism of FA is based on the adsorption process forming a film barrier layer protect the steel from acid attack. The adsorption is found to obey Frundlich model. The inhibition efficiency increased by increasing inhibitor concentration and decreased with temperature. Some thermodynamic parameters for adsorption process are deduced and discussed. Keywords: C-steel, famotidine, Adsorption, Corrosion

Effects of Antioxidant Supplements on the Survival and Differentiation of Stem Cells

Although physiological levels of reactive oxygen species (ROS) are required to maintain the self-renewal capacity of stem cells, elevated ROS levels can induce chromosomal aberrations, mitochondrial DNA damage, and defective stem cell differentiation. Over the past decade, several studies have shown that antioxidants can not only mitigate oxidative stress and improve stem cell survival but also affect the potency and differentiation of these cells. Further beneficial effects of antioxidants include increasing genomic stability, improving the adhesion of stem cells to culture media, and enabling researchers to manipulate stem cell proliferation by using different doses of antioxidants. These findings can have several clinical implications, such as improving neurogenesis in patients with stroke and neurodegenerative diseases, as well as improving the regeneration of infarcted myocardial tissue and the banking of spermatogonial stem cells. This article reviews the cellular and molecular effects of antioxidant supplementation to cultured or transplanted stem cells and draws up recommendations for further research in this area

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Correction to: Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

The original version of this article unfortunately contained a mistake