: Electrochemical behaviour of Oxygen Plasma ion implanted NiTi alloy for Biomedical Applications

Nickel-titanium alloy (Nitinol - NiTi) has attractive and unique properties such as super elasticity and shape memory effect and it is used in orthopaedic and orthodontic applications. However NiTi releases harmful Ni ions from the implants to living tissues that could be toxic to cell, tissue and organs. Therefore, it is essential to have a barrier for such release of ions from the implant. In this work, NiTi alloy was implanted with oxygen ions by plasma immersion ion implantation (O-PIII). The surface was characterized by FESEM and EDS. The corrosion behavior of the treated and untreated samples was investigated through electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization studies in simulated body fluid (Hanks 19 solution). The investigation of the samples showed the formation of a thin oxide layer on the coated samples. Corrosion resistance of the oxygen implanted sample shows better corrosion resistance compared to that of untreated samples. Electrochemical impedance data of the substrate and treated samples were fitted with two time constant equivalent circuits

Corrosion behaviour and effect of surface finishing in the formation of nano structure on NiTi Alloy

Nitinol 13 NiTi (Nickel-titanium alloy) is used in orthopaedic and orthodontic applications due to its attractive and exceptional properties such as super elasticity and shape memory effect. Conversely NiTi releases harmful Ni ions from the implants to living tissues that could be toxic to cell, tissue and organs. Thus, it is necessary to have a barrier for such release of ions from the implant. In the present work, we investigate the formation of nano structured oxide layers by anodic oxidation on different surface finished (mirror finished, 600 and 400grit polished) nickel - titanium alloy (NiTi) in electrolyte solution containing Ethylene glycol and NH4F. The anodized surface was characterized by XRD, FESEM and EDS. The corrosion behavior of the treated and untreated samples was investigated through electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization studies in simulated body fluid (Hanks 19 solution). The investigations show that the native oxide on the sample is replaced by nano structure by anodisation. Corrosion resistance of the anodized sample is comparable with that of the untreated samples

Sonophotocatalytic mineralization of Norflurazon in aqueous environment

Norflurazon (4-chloro-5-(methylamino)-2-[3- trifluoromethyl)phenyl]pyridazin-3(2H)-one; C12H9ClF3N3O) is an excellent weed controlling agent being practiced in the agricultural lands. The excessive addition or the undissolved Norflurazon (maximum solubility 28 mg/L at 25 C) enters into the aquatic environment and causes the adverse effects associated with its high concentration. To avoid the perilous effects, visible light assisted photocatalysis set-up coupled with the 42 kHz ultrasound producing bath type sonicator is used to completely mineralize the Norflurazon. TiO2, ZnO and gold loaded zinc oxide nanocatalysts were utilized to study the mineralization of Norflurazon. AueZnO shows the greater efficiency for the sonophotocatalytic removal of Norflurazon among the various nanocatalysts employed to study the mineralization. The order of Norflurazon mineralization was sonophotocatalysis > sonocatalysis > photocatalysis. The additive effect was achieved for the sonophotocatalytic degradation. The high performance liquid chromatography (HPLC) and liquid chromatography-mass spectrometric (LCMS) analyses were employed to identify the various intermediates produced during the mineralization. The identification of four pseudo molecular ions and various intermediates using the LCMS analysis evidently suggests the sonophotocatalytic degradation was preceded in various decay pathways. A suitable mechanism has been proposed for the sonophotocatalytic mineralization of Norflurazo

Morphological and molecular characterization of Colletotrichum musae isolates from various banana (Musa spp.) cultivars

Forty Colletotrichum musae isolates were recovered from ten different banana cultivars (Musa spp.) exhibiting the symptoms of both crown rot and anthracnose. The isolates were characterized morphologically and with molecular tools. Based on morphological characters in culture, the 40 C. musae isolates were included in four groups. Group I consisted of fast growing isolates with pinkish to light orange mycelia; group II included isolates with sparse, slow growing, suppressed, light orange mycelia; group III consisted of isolates with dense, fast growing, orange mycelia; and group IV included isolates with profuse cottony mycelia, mostly white to very light orange colour. Twelve isolates of C. musae were further selected and tested with RAPD primers for their genetic diversity. The RAPD dendrogram grouped the 12 isolates of C. musae in three clusters. Based on RAPD patterns, the similarity index (SI) within C. musae isolates ranged from 41.66 to 100%. Thus, the RAPD analysis revealed a high genetic variability in C. musae isolated from different banana cultivars. This might explain the differences in cultural characteristics of different isolates

Corrosion behaviour of Tetrahedral Amorphous Carbon (ta-C) filled Titanium Nano Tubes

TiO2 nanotubes were formed by anodic oxidation on Ti–6Al–7Nb and the nanotubes were filled with tetrahedral amorphous carbon (ta-C) by cathodic arc Evaporation (CAE). The samples were characterized by field emission scanning electron microscopy (FESEM), Energy dispersive spectroscopy (EDS) and micro Raman studies. The corrosion behaviour of the Ti-6Al-7Nb substrate, substrate with self-organized TiO2 nanotubes (TNT) and ta-C filled TiO2 nano tubes (ta-C TNT) were investigated through electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization studies in simulated body fluid (Hanks' solution). The investigations show that the native oxide on the sample is replaced by a self assembled nano array by an anodisation process and the pores can be filled with ta-C. Potentiodynamic polarization and electrochemical impedance studies of ta-C filled TNT sample show that the corrosion resistance is comparable with TNT samples

Effect of oxygen plasma immersion ion implantation on the formation of nanostructures over Ni-Ti alloy

Ni–Ti alloy has been implanted with oxygen ions by plasma immersion ion implantation (PIII-O). Ni–Ti–O nanotubes are formed by anodic oxidation of PIII-O Ni–Ti alloy. The surface of the modified alloy samples has been characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). The corrosion behaviors of the Ni–Ti substrate, PIII-O and anodized PIII-O samples have been investigated through electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization studies in simulated body fluid (Hanks' solution). It has been observed that oxygen ion implantation leads to the formation of a thin oxide layer on the Ni–Ti alloy. Anodization of the implanted alloy results in Ni–Ti–O nanotubes. Corrosion resistance of the PIII-O and anodized PIII-O samples shows better corrosion resistance compared to that of untreated alloy

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Not AvailableThe protective effect of PUFA concentrate prepared from fish oil on isoproterenol-induced myocardial infarction in male albino rats was investigated with respect to changes in the levels of diagnostic marker enzymes, cholesterol, triglycerides, free fatty acids, phospholipids, reduced glutathione (GSH) and lipid peroxides (LPO). Administration of PUFA concentrate significantly prevented the isoproterenol-induced elevation in the levels of plasma diagnostic marker enzymes (ALT [93.5 % ], AST [95.6 % ], LDH [94.7 % ] and CPK [96.1 % ]). PUFA concentrate feeding exerted a significant antilipidemic effect against isoproterenol-induced myocardial infarction by reducing the levels of lipid components in plasma (cholesterol [71.5 % ]), triglycerides [79.7 % ] and free fatty acids [70.7 % ] and heart tissue (cholesterol [81.4 % ]), (triglycerides [76.3%] and free fatty acids [78.6 % ]). A tendency to prevent the isoproterenol-induced phospholipids depletion (74.4 % ) in the myocardium of experimental rats was also observed. The level of lipid peroxidation was also found to be significantly lower in PUFA treated animals (2.72 ± 0.15 nmol / ml in plasma; 1.18 ± 0.08 nmol / mg protein in heart tissue) as compared to that of isoproterenol- injected groups (5.77 ± 0.43 nmol / ml in plasma; 2.14 ± 0.15 nmol / mg protein in heart tissue) of rats. Also the level of reduced GSH significantly higher in the heart tissue of PUFA administered experimental rats (5.65 ± 0.98 μg / g) as compared to myocardial infarction induced control rats (2.39 ± 0.18 μg / g). The results of the present study indicate that the overall cardioprotective effect of PUFA concentrate is probably related to its ability to inhibit lipid accumulation by its hypolipidaemic property.Not Availabl

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Not AvailableThe protective effect of squalene on membrane function and mineral status was examined in isoproterenol-induced myocardial infarction in male albino rats. The pretreatment with squalene at 2% level along with feed significantly reduced the isoproterenol-induced rise in the levels of plasma diagnostic marker enzymes. It counteracted isoproterenol-induced lipid peroxidation in plasma and heart tissue, and maintained the level of reduced glutathione in the heart tissue at near normalcy. Supplementation of squalene also exerted membrane stabilizing action against isoproterenol-induced myocardial infarction by maintaining the activities of membrane-bound ATPases in heart tissue and the mineral status (sodium, potassium and calcium) in plasma and heart tissue at near normal levels. The cardioprotective effect of squalene might be ascribable to its antioxidant nature and membrane stabilizing property.Not Availabl

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Not AvailableFish collected from five different locations from the Calicut region, India were analysed for the levels of organochlorine pesticides (OCPs) and heavy metal (HM) residues in order to elucidate the status of these chemical contaminants in fish and shellfish meant for human consumption. The highest concentrations of OCPs detected in the edible portion of fish were 10.47, 70.57 and 28.35 ng g −1 wet weight, in marine, brackish water and freshwater, respectively. BHC and heptachlor epoxide formed the major share of OCPs in the marine fish while BHCs contributed to the major share in the freshwater and brackish water fish. The DDT (sum of DDT and its metabolites) ranged from 0.05 to 8 ng g −1 in the samples irrespective of the habitat. Among the HMs, Cu, Zn, Mn and Cr were present in the samples irrespective of the place of collection. About 22% of the samples from the freshwater area contained marginally higher lead content above the legal limit of 0.2 – 0.4 μg g −1. The Cr content ranged from 0.1 to 1.1 μg g −1 in the fish with marginally higher content in the fish from freshwater and marine regions (0.55 – 1.1 μg g −1). Mercury was detected in the samples (55%) from marine habitat only. The concentrations of OCPs and HMs in the samples, in general, were below the maximum residual level recommended by various organizations.Not Availabl