The absorption efficiency of any drug in blood is of prime importance. Compounds having the general formula: Kn[M(FO)2(H2O)2] · xH2O, where (M = Cu(II) or Fe(III), n = 2 or 1, FO = folate anion, x = 2 or 3 with respect), were prepared, and their absorption efficiency in rodent's blood was determined. The obtained compounds were characterized by elemental analysis, infrared as well as thermogravimetric analysis and polarization of light. The results suggest that the two folate complexes were formed in 1 : 2 molar ratio (metal : folic acid) which acted as a bidentate ligand through both carboxylic groups. Polarization of light proved that the folate complexes have symmetric geometry. Biological application proved that Cu(II) and Fe(III) complexes were absorbed more efficiently in rodent blood than folic acid itself.
Copper nanoparticles (nano‐Cu) were electrodeposited on the surface of glassy carbon electrode (GCE) potentiostatically at −0.6 V vs. Ag/AgCl for 60 s. The developed nano‐copper modified glassy carbon electrode (nano‐Cu/GCE) was optimized and utilized for electrochemical assay of chemical oxygen demand (COD) using glycine as a standard. The surface morphology and chemical composition of nano‐Cu/GCE were investigated using scanning electron microscope (SEM) and energy dispersive X‐ray spectrometer (EDX), respectively. The electrochemical behavior was investigated using linear sweep voltammetry (LSV) which is characterized by a remarkable anodic peak at ∼0.6 V, compared to bare GCE. This indicates that nano‐Cu enhances significantly the electrochemical oxidation of glycine. The effect of different deposition parameters, such as Cu2+ concentration, deposition potential, deposition time, pH, and scan rate on the response of the developed sensor were investigated. The optimized nano‐Cu/GCE based COD sensor exhibited a linear range of 15 to 629.3 ppm, and a lower limit of detection (LOD) of 1.7 ppm (S/N=3). This developed method exhibited high tolerance level to chloride ion (0.35 M chloride ion has minimal influence). The analytical utility of the prepared COD sensor was demonstrated by investigating the COD recovery (99.8±4.3) and the assay of COD in different water samples. The results obtained were verified using the standard dichromate method.
Background: Cranial neuropathy in rheumatoid arthritis (RA) is relatively rare compared to the frequently reported peripheral neuropathy. Methods: We investigated the occurrence of subclinical cranial and peripheral nerve involvement in 55 patients with RA. Results: Patients had a mean age of 43.1 years and a mean duration of illness of 6.4 years. All patients presented with electrophysiological findings suggestive of peripheral neuropathy. In addition, 69.1% of them had entrapment neuropathies, in which carpal tunnel syndrome was the most common (54.6%). Sensorimotor neuropathy at sites other than usual entrapment sites was diagnosed in 70.9%, while bilateral distal sensory neuropathy in lower limbs was identified in 29.1%. Among cranial nerves examined, optic and vestibulocochlear neuropathies were common (29.1% of eyes and 40% of ears examined). Spinal accessory neuropathy was reported in 21.8% of records. Neither facial nor trigeminal nerves were affected. Electrophysiological characteristics of neuropathies were indicative of axon loss. Significant association was identified between neuropathy and patients’ ages (P < 0.01), duration of the illness (P < 0.001), presence of rheumatoid nodules (P < 0.001) and disease stages (P < 0.001). Conclusions: Our results indicate that cranial and non‐compressive neuropathies are not uncommon in RA. This extends the pathologic disease spectrum. We do not confirm, but suggest the contribution of chronic immune‐mediated vasculitis and/or neurotoxicity in RA neuropathies. Of clinical importance, subclinical neuropathy may never progress and/or be of clinical significance, which contradicts that of comparable diseases, such as systemic lupus erythematosus. Advances in genetics implicate a complex immune genetics which controls susceptibilities and adaptive molecular mechanisms as a culprit of phenotypical heterogenicity among related diseases.
Purpose In recent years, zeolites have been highlighted as a new component in many industrial applications owing to their unique properties. The purpose of this study is to apply three prepared types of zeolites Na-X, Na-Y and hydroxysodalite (Na-HS) in anticorrosive paint formulations to be evaluated as a partial replacement to zinc phosphate in anticorrosive paint formulations to protect carbon steel. Design/methodology/approach The three types of zeolites were characterized using different instrumental analysis such as X-ray diffraction, scanning electron microscopy and X-ray fluorescence. Evaluation of zeolites was done using American society for material and testing. Then, they were incorporated in paint formulations based on medium oil-modified soya-bean dehydrated castor oil alkyd resin in the presence and absence of zinc phosphate. Their corrosion behavior was estimated using both immersion test and electrochemical impedance measurements in 3.5% NaCl. Findings Generally, the prepared zeolites exhibited good corrosion protection performance, but in presence of zinc phosphate the performance was better. This proves that, zeolites by themselves can resist corrosion but not efficiently, while in presence of zinc phosphate and owing to a synergistic effect between them, the performance was better. This opens the way to partial replacement of zinc phosphate with another safer and cheaper ingredient, which is zeolite. Practical implications The three zeolites can be applied in many industries besides the paint industry, such as reinforcing filler in rubber, plastics and ceramic composites, also can be applied in paper filling, paper coatings and electrical insulation. Originality/value The three zeolites are environmentally friendly materials that can partially replace other expensive anticorrosive pigments (e.g. zinc phosphate).
As a first step towards studying pitting corrosion of Zn in aerated neutral 1.0 M sodium thiosulphate solution (pH 6.6), we have reported the results of cyclic polarization measurements on the passivity and passivity breakdown of Zn in this solution. The recorded voltammograms involved two oxidation processes labeled as AI and AII, and two reduction processes labeled as CII and CI on the forward (anodic) and reverse (cathodic) scans, respectively. The cathodic peak CII was attributed to the reduction of the pitting corrosion products (process AII). On the other hand, the cathodic process CI was related to the reduction of Zn2+ species formed during the course of the forward scan (process AI and the subsequent formation of the passive region), and the reduction of the adsorbed S2O3 2− anions to S2− and SO3 2−. The reduction products of S2O3 2−, namely S2− and SO3 2− anions, were detected in solution as a function of starting potential and time of holding the electrode at a cathodic potential of −2.0 V (Ag/AgCl). These anions were found to cooperate with the aggressive S2O3 2− anion itself in passivity breakdown and initiation of pitting corrosion. The effect of solution temperature (15–70 ºC) on the cyclic polarization behaviour of Zn was also studied, and metastable and stable pitting events observed at high temperatures were discussed. The morphology of pitting was also studied by ex situ scanning electron microscopy (SEM) as a function of applied anodic potential, bulk concentration of S2O3 2− and solution temperature. Cross-sectional view of pits revealed the formation of irregular deep and shallow pits. The aspect ratios (the ratio of pit width to pit depth) of the growing pits were estimated as a function of potential, electrolyte concentration and solution temperature. The aspect ratio of the growing pits was found to be potential and concentration independent, while it increased with temperature.
The anodic behaviour and corrosion of tin in various concentrations (0.05-0.7M) of succinic acid were studied using cyclic voltammetry. The potentiodynamic anodic polarization curves exhibit active/passive transition. The active dissolution of tin involves one anodic peak. The cathodic curve exhibits one cathodic peak corresponding to the reduction of the passive layer. The ratio of the anodic charge/cathodic charge is more than unity indicating that the passive layer is very thin and the dissolution products are mainly soluble species. Additions of some polyethylene glycols to the succinic acid solution decrease the anodic peak current and shift the peak potential in the negative direction. These changes depend on the concentration and molecular weight of the polyethylene glycol added. The effect of the inhibitors decreases in the following order: (PEG) 6000 > (PEG) 4000 > (PEG) 1200 . The inhibition efficiency decreases with increase in temperature, suggesting physical adsorption.
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