Seizures following chloroquine treatment of type II lepra reaction: a case report

Large, complex hypopharyngeal defects that include mucosa and cervical skin, and that result from debridement of orocutaneous fistulas secondary to failed repairs of laryngectomy defects, are difficult to treat, especially when previous irradiation has damaged adjacent tissues. We have found that such defects can be repaired sufficiently in one stage using a latissimus dorsi musculocutaneous free flap. The wound is debrided until only healthy tissue remains. The skin paddle of the free flap is then used to reconstruct the hypopharyngeal mucosal defect, whereas the muscular portion serves to cover any cervical tissue that remains exposed. A split-thickness skin graft is then placed over the muscle to complete the repair. The resulting reconstruction is free of excess bulk, has no radiation damage, is well vascularized, and has an acceptable appearance.     

Adsorption and Quantum Chemical Studies on the Inhibition Potentials of Some Thiosemicarbazides for the Corrosion of Mild Steel in Acidic Medium

Three thiosemicarbazides, namely 2-(2-aminophenyl)-N phenylhydrazinecarbothioamide (AP4PT), N,2-diphenylhydrazinecarbothioamide (D4PT) and 2-(2-hydroxyphenyl)-N-phenyl hydrazinecarbothioamide (HP4PT), were investigated as corrosion inhibitors for mild steel in H₂SO₄ solution using gravimetric and gasometric methods. The results revealed that they all inhibit corrosion and their % inhibition efficiencies (%IE) follow the order: AP4PT > HP4PT > D4PT. The %IE obtained from the gravimetric and gasometric experiments were in good agreement. The thermodynamic parameters obtained support a physical adsorption mechanism and the adsorption followed the Langmuir adsorption isotherm. Some quantum chemical parameters were calculated using different methods and correlated with the experimental %IE. Quantitative structure activity relationship (QSAR) approach was used on a composite index of some quantum chemical parameters to characterize the inhibition performance of the studied molecules. The results showed that the %IE were closely related to some of the quantum chemical parameters, but with varying degrees. The calculated/theoretical %IE of the molecules were found to be close to their experimental %IE. The local reactivity has been studied through the Fukui and condensed softness indices in order to predict both the reactive centers and to know the possible sites of nucleophilic and electrophilic attacks.     

Metathesis of Fatty Acid ester derivatives in 1,1-dialkyl and 1,2,3-trialkyl imidazolium type ionic liquids

The self-metathesis of methyl oleate and methyl ricinoleate was carried out in the presence of ruthenium alkylidene catalysts 1-4 in [bmim] and [bdmim][X] type ionic liquids (RTILs) (X = PF(6) (-), BF(4) (-) and NTf(2) (-)) using the gas chromatographic technique. Best catalytic performance was obtained in [bdmim][X] type ionic liquids when compared with [bmim][X] type ionic liquids. Catalyst recycling studies were also carried out in the room temperature ionic liquids (RTILs) with catalysts 1-4 in order to explore their possible industrial application.     

Polyethylene glycol and polyvinyl alcohol as corrosion inhibitors for aluminium in acidic medium

The corrosion inhibition of aluminum in H₂SO₄ in the presence of polyethylene glycol (PEG) and polyvinyl alcohol (PVA) as inhibitors at 30–60 °C was studied using gravimetric, gasometric, and thermometric techniques. The inhibition efficiency (%I) increased with increase in concentration of the inhibitors. Increase in temperature increased the corrosion rate in the absence and presence of inhibitors but decreased the inhibition efficiency. Both PEG and PVA were found to obey Temkin adsorption isotherm at all concentrations and temperatures studied. Phenomenon of physical adsorption is proposed from the activation parameters obtained. Thermodynamic parameters reveal that the adsorption process is spontaneous. PEG was found to be a better inhibitor than PVA. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Highly durable macromolecular epoxy resin as anticorrosive coating material for carbon steel in 3% NaCl: Computational supported experimental studies

The purpose of present study is in the direction of development of an anticorrosive coating formulation of high durability for carbon steel corrosion in 3 wt% NaCl medium. The formulation comprises of a macromolecular epoxy coating (DGEDDS-MDA) based bisphenol S diglycidyl ether (DGEDDS) cured with a methylene dianiline (MDA). The formulation was characterized by FT-IR spectroscopy method. Performance of the epoxy coating was represented using PDP and EIS approaches. The formulation acts as effective anticorrosive coating for long durability (180 days). Surfaces of the specimens before and after 180 days exposure to UV radiation were examined using SEM. PDP, SEM, and EIS studies showed that DGEDDS-MDA acted as highly durable and effective anticorrosive formulation. Results also showed that the formulation acts as interface type inhibitor and its presence enhances the polarization resistance (R_p) value. DFT study suggests that the formulation DGEDDS-MDA possesses strong ability to interact with metal surface through its several electron rich centers. MD and MC simulations showed that studied formulation effectively adsorb on the substrate (metallic surface). Results of EIS, PDP, and SEM studies (experimental) were well-supported by DFT, MD, and MC (computational) simulations.     

Inhibitory action of Phyllanthus amarus extracts on the corrosion of mild steel in acidic media

The inhibitive action of leaves (LV), seeds (SD) and a combination of leaves and seeds (LVSD) extracts of Phyllanthus amarus on mild steel corrosion in HCl and H₂SO₄ solutions was studied using weight loss and gasometric techniques. The results indicate that the extracts functioned as a good inhibitor in both environments and inhibition efficiency increased with extracts concentration. Temperature studies revealed an increase in inhibition efficiency with rise in temperature and activation energies decreased in the presence of the extract. A mechanism of chemical adsorption of the plants components on the surface of the metal is proposed for the inhibition behaviour. The adsorption characteristics of the inhibitor were approximated by Temkin isotherm.     

DGEBA-polyaminoamide as effective anti-corrosive material for 15CDV6 steel in NaCl medium: Computational and experimental studies

The present study is focusing on evaluating theoretically and experimentally stability and type of interactions between the epoxy resin bisphenol A diglycidyl ether (DGEBA)-polyaminoamide anticorrosive coating and high strength low alloy steel surface 15CDV6. The coated steel samples were subjected to a harsh environment of an electrolyte solution of 3 wt % NaCl to simulate the corrosive marine environment. The performance of the epoxy coating was investigated using electrochemical impedance spectroscopy (EIS). The EIS results revealed the occurrence of some deterioration in the film after subjecting it to a harsh environment for 4392 h, because the impedance of the coating dropped by about 1.4 kΩ.cm². Surface morphological study of metallic specimens before and after exposing to the simulated marine environment (3 wt % NaCl) was carried out using scanning electron microscopy, energy dispersive spectroscopy (EDS), and optical microscope (OM) methods. The interactions between DGEBA-polyaminoamide and the metallic surface were further carried out using computation modeling such as density functional theory (DFT)-based quantum chemical calculations, Monte Carlo (MC), and molecular dynamics (MD) simulations. Results showed that DGEBA-polyaminoamide possesses a strong tendency to adhere and inhibits the corrosive dissolution of 15CDV6 steel surface in the stimulated marine environment. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48402.     

Effect of halide ions on the corrosion inhibition of aluminium in alkaline medium using polyvinyl alcohol

The corrosion inhibition of aluminum in NaOH in the presence of polyvinyl alcohol (PVA) at 30 and 40°C and the effect of addition of halides (KCl, KBr, KI) were studied using weight loss and hydrogen evolution methods. Results obtained showed that PVA acts as a corrosion inhibitor in the alkaline environment. The inhibition efficiency increased with increase in concentration of PVA and synergistically increased on the addition of the halides but however decreased with rise in temperature. The phenomenon of physical adsorption is proposed from the obtained E_a and Q_ads values. PVA was found to obey Freundlich and Frumkin adsorption isotherms. The increase in inhibition efficiency I (%), surface coverage θ values as well as synergistic parameter, S_I were found to be in the order I^? > Br^? > Cl^?, which clearly indicates that the radii and electronegativity of the halides play a significant role in the adsorption process. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2810–2816, 2007