University of Madras

About: University of Madras is a education organization based out in Chennai, Tamil Nadu, India. It is known for research contribution in the topics: Ring (chemistry) & Lipid peroxidation. The organization has 8496 authors who have published 11369 publications receiving 211152 citations. The organization is also known as: Madras University & University of Chennai.

Electroless Ni–Co–P ternary alloy deposits: preparation and characteristics

Abstract: Electroless Ni–Co–P ternary alloy deposits were prepared by varying the metallic ratio and were characterized using X-ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and vibration sample magnetometer. The plating rate of electroless Ni–Co–P deposits is a function of concentration of sodium hypophosphite, pH of the plating bath, plating time and the metallic ratio. With increase in metallic ratio, the cobalt content of the deposits increases with a simultaneous decrease in the nickel content, while the phosphorus content decreases slightly. The electroless Ni–Co–P deposits of the present study are amorphous in their as-deposited condition. The DSC trace exhibits three distinct exothermic peaks, corresponding to the relaxation of lattice strain during the phase separation, the phase transformation of amorphous phase to nickel and nickel phosphide phases and the transformation of metastable phases to stable nickel phosphide phase. The XRD pattern of electroless Ni–Co–P deposits confirms the formation of Ni, Ni5P2, Ni12P5 and Ni3P phases during annealing at 300 and 400 °C for 1 h. Thermomagnetic study exhibits the Curie transition of nickel and non-stoichiometric Ni3Co based alloys. Being amorphous in nature, the electroless Ni–Co–P deposits exhibit soft magnetic characteristics. The saturation magnetization, remanence and coercivity increase with cobalt content of the deposit.

Influence of thermal annealing on the dielectric properties and electrical relaxation behaviour in nanostructured CoFe2O4 ferrite

Abstract: Nanocrystalline cobalt ferrite particles with the grain size of 8 nm were synthesized by using the co-precipitation technique and subsequently heat treated to obtain larger grain sizes. The effect of grain size, cation distribution, frequency and temperature on their dielectric properties has been studied. The dielectric constant (e') of 8 nm grains is found to be an order of magnitude higher and the dielectric loss (tanδ) is an order of magnitude smaller compared to those of the micron-size particles. The dielectric relaxation is found to be non-Debye in nature with the activation energy decreasing with thermal annealing due to structural perfection.

Gestational Cadmium Exposure-Induced Ovotoxicity Delays Puberty through Oxidative Stress and Impaired Steroid Hormone Levels

Abstract: Cadmium (Cd), an environmental pollutant, has been shown to be highly toxic to both humans and animals. Its widespread industrial use has led to its accumulation in the environment. Cd has been shown to target multiple organs following acute intoxication, causing nephrotoxicity, immunotoxicity, osteotoxicity, and reproductive toxicity. Cd can cross the placental barrier and cause a wide range of defects during fetal development. The current study was aimed to assess the effect of Cd on the female reproductive system. Female rats were exposed to Cd [50/200 ppm] from embryonic day 9 to 21 through drinking water. Serum steroid hormone concentrations, hematological parameters, antioxidant enzyme levels, and ovarian histopathology were described. Water consumption, gravid uterine/body weight decreased in both the doses of Cd-treated dams. The hematological parameters analyzed in rat pups showed a significant reduction in both doses of Cd studied, while hemoglobin showed a significant reduction in 200 ppm Cd treatment alone. MCHC levels did not show any variation in 50 ppm Cd treatment, while 200 ppm Cd treatment significantly increased. Specific activities of superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, glutathione-S-transferase, and serum testosterone, estradiol, and progesterone were significantly decreased. The levels of hydrogen peroxide and lipid peroxidation were increased in 50 and 200 ppm Cd-treated rats. These changes were accompanied with disrupted ovarian histoarchitecture, an extended estrous cycle, and delayed pubertal onset in Cd-treated rats. The data generated from the present study suggest that gestational Cd treatment induces ovarian toxicity and reproductive dysfunction through increased oxidative stress.