Fe-P and Fe-P-Pt co-deposits as hydrogen electrodes in alkaline solution

Fe-P and Fe-P-Pt alloys for use as electrodes for alkaline water electrolysis are prepared by an electroplating technique which employs an acidic complex bath solution. After heat treatment, the plated alloys act as effective electrocatalytic materials by lowering the hydrogen overpotential sufficiently. The improved electrocatalytic activity is due to an increase in effective surface area, a change in surface features upon heat treatment, and the presence of traces of platinum. Electrodes of the plated alloys are stable even in a highly corrosive electrolytic medium (6 M KOH). © 2001 Elsevier Science B.V. All rights reserved

The In Vivo Role of the RP-Mdm2-p53 Pathway in Signaling Oncogenic Stress Induced by pRb Inactivation and Ras Overexpression

The Mdm2-p53 tumor suppression pathway plays a vital role in regulating cellular homeostasis by integrating a variety of stressors and eliciting effects on cell growth and proliferation. Recent studies have demonstrated an in vivo signaling pathway mediated by ribosomal protein (RP)-Mdm2 interaction that responds to ribosome biogenesis stress and evokes a protective p53 reaction. It has been shown that mice harboring a Cys-to-Phe mutation in the zinc finger of Mdm2 that specifically disrupts RP L11-Mdm2 binding are prone to accelerated lymphomagenesis in an oncogenic c-Myc driven mouse model of Burkitt's lymphoma. Because most oncogenes when upregulated simultaneously promote both cellular growth and proliferation, it therefore stands to reason that the RP-Mdm2-p53 pathway might also be essential in response to oncogenes other than c-Myc. Using genetically engineered mice, we now show that disruption of the RP-Mdm2-p53 pathway by an Mdm2C305F mutation does not accelerate prostatic tumorigenesis induced by inactivation of the pRb family proteins (pRb/p107/p130). In contrast, loss of p19Arf greatly accelerates the progression of prostate cancer induced by inhibition of pRb family proteins. Moreover, using ectopically expressed oncogenic H-Ras we demonstrate that p53 response remains intact in the Mdm2C305F mutant MEF cells. Thus, unlike the p19Arf-Mdm2-p53 pathway, which is considered a general oncogenic response pathway, the RP-Mdm2-p53 pathway appears to specifically suppress tumorigenesis induced by oncogenic c-Myc

Methanol oxidative fuel cell: Electrochemical synthesis and characterization of low-priced WO3-Pt anode material

Electroplating of WO3-Pt has been carried out using a suitable plating bath solution and optimum working conditions. X-ray and SEM studies of the deposit reveal a smooth and uniform distribution of microparticles on the surface. New phases of the plated material appear on heat treatment. The electrocatalytic activity of the WO3-Pt co-deposit is considerably higher than for platinum alone. WO3 in the WO3-Pt co-deposit reduces the retardation effect of methanol oxidation by the reaction intermediate observed in the case of Pt alone. WO3-Pt co-deposits exhibit low overpotential for methanol oxidation in both acidic and alkaline media at low temperature and have good corrosion resistance in electrolytic media. The electrochemical parameters for methanol oxidation of these co-deposits depend on trace amounts of the platinum, heat treatment and the microstructure of the coating. © Springer-Verlag 2004

Studies on isolation, purification and inhibition of carboxylesterase from the midgut of fall armyworm (Spodoptera frugiperda)

The fall army worm (FAW) (Spodoptera frugiperda) is a polyphagous pest which causes damage to commercially important cultivated crops such as maize, rice, sorghum, cotton and also different vegetable crops. Carboxyl esterases (CarE, EC.3.1.1.1) or esterases are enzymes in the carboxyl / cholinesterase gene family that catalyze the hydrolysis of carboxyl esters. The carboxylesterases enzyme are the detoxification enzymes in FAW. Therefore, the inhibition of carboxylesterases from FAW would help in pest management. In this scenario, Isolation, purification and inhibition studies were carried out on the midgut carboxylesterase enzyme of FAW. Through a combination of steps including centrifugation, ammonium sulfate gradient precipitation, DEAE-Cellulose ion exchange chromatography, the enzyme was purified from fifth instar larvae of FAW. The final purified carboxylesterase after ion exchange chromatography had a specific activity of 7282.22 units / mg protein, 5.6 – fold of crude homogenate, and a yield of 25%. The purity of esterase was established by PAGE and SDS-PAGE. The SDS-PAGE revealed a molecular weight of approximately 45kDa to 66kDa. Our studies on the purified midgut carboxylesterase showed complete inhibition by organophosphorous inhibitor (10-4 M). The enzyme was also inhibited by 1x concentration of Lizol (disinfectant) and by different natural extracts (1x) as well

Electroless deposition of Fe-P, Fe-P-Pt alloys

213-215Fe-P and Fe-P-Pt alloys have been developed by electroless plating technique using suitable acidic bath solution and plating conditions. The alloys are characterised to be used as cathode materials for hydrogen evolution reaction in alkaline solution. The alloys exhibited an overpotential of 332 (Fe-P-Pt) and 412 mVs (Fe-P) for about 70 h of continuous electrolysis in 30% KOH at a current density of 100 mA/cm2 and temperature 323 K. The electrocatalytic activity depends on the alloying elements and the composition of the alloy. Electrokinetic parameters for hydrogen evolution reaction are evaluated

Electroless deposition and characterization of Fe-W-Pt alloys

The electroless plating of Fe-W-Pt alloys and their characterization as cathode materials for alkaline water electrolysis were studied. These alloys afford good corrosion resistance towards 30 KOH. Trace amounts of Pt in the alloy exhibit water electrolysis. The heat treatment enhances the catalytic activity of the alloy

Microstructure, surface and electrochemical studies of electroless Cr-P coatings tailored for the methanol oxidative fuel cell

Cr-P is a new material of great importance as a decorative coating with nickel in automobile industries. Electroless plating of Cr-P alloy has been carried out using a suitable plating bath solution and working conditions. The deposit is characterized by X-ray diffraction, transmission electron microscopy, energy-dispersive X-ray diffraction, X-ray photoelectron spectroscopy and polarization techniques. New phases appear on heat treatment of the coating. The composition (Cr/P) of the coating and the oxidation states of alloying elements vary from the surface to the bulk of the material. The coatings acted as a novel electrode material with good electrocatalytic activity (low overvoltage) and good corrosion resistance for anodic oxidation of methanol in H 2SO4 at normal working temperature. The good corrosion resistance of the Cr-P film is accounted for by the existence of a double oxyhydroxide passive film on the surface. The electrocatalytic activity of Cr-P is very high when compared with chromium alone. © Springer-Verlag 2005