N. Subbarami Reddy

Development of Gelatin Based Inorganic Nanocomposite Hydrogels for Inactivation of Bacteria

In this investigation, silver nanocomposite hydrogels were developed by using acrylamide and biodegradable gelatin. Silver nanoparticles were generated throughout the hydrogel networks using in situ method by incorporating Ag+ ions and the subsequent treatment with sodium borohydride. The effect of gelatin on the swelling studies was investigated. The hydrogel synthesized silver nanocomposites were characterized by using Fourier transform infrared, UV–Visible spectroscopy, X-ray diffraction, thermogravimetric analysis, scanning electron and transmission electron microscopy techniques. The biodegradable gelatin-based silver nanocomposite hydrogels were tested for antibacterial properties. The results indicate that these biodegradable silver nanocomposite hydrogels can be useful in medical applications, as antibacterial agents.

Spectrophotometric determination of copper(II) and its application to a plant sample containing zinc, iron, and manganese

Abstract Salicylaldehyde thiosemicarbazone instantaneously forms a green complex with copper(II) in the optimum pH range 5–7. A fivefold molar excess of the reagent is sufficient for the full development of the color. Beers law is obeyed in the range 0.5–6.0 ppm of copper. The optimum concentration range as evaluated by Ringboms method is 1.4–5.8 ppm. At 375 nm the sensitivity of the reaction and the molar absorptivity are 0.006 μg cm−2 and 9.2 × 103 liters mol−1 cm−1, respectively. The effects of pH, reagent concentration, time, order of addition of the solutions, and the interference of various ions were investigated. Copper in plant samples, containing zinc, iron, and manganese, was determined.

Electron Spin Resonance study of gamma irradiated MA-AMPS copolymer

Electron Spin Resonance (ESR) spectra of gamma irradiated methylacrylamide-2-acrylamido-2-methyl-propanesulphonic acid (MA-AMPS) are recorded to identify the radical species formed during the irradiation of the copolymer. The ESR spectrum observed for irradiated MA-AMPS copolymer at liquid nitrogen temperature (LNT) (77 r K) is an asymmetric triplet; while the spectrum observed at room temperature (RT) is a quintet. The intensity distribution of both the spectra deviated appreciably from the expected theoretical values. Computer simulations are employed to analyze the ESR spectra observed at different temperatures. The triplet spectrum observed at LNT is simulated to be a superposition of component spectra arising from macroradicals of the type∼CH 2 - \dot {\rm C} H-CH 2 ∼ (I), radicals of the type \dot {\rm C} H 2 SO 3 H (II), and peroxy radicals (III). In contrast, the RT spectrum is simulated to be a superposition of component spectra arising due to radicals I, II, III together with the component quartet assigned to methyl radicals ( \dot {\rm C} H 3 ). The formation of such free radicals in irradiated copolymer is discussed.

Electron spin resonance and fourier transform infrared study of gamma irradiated poly (phenyl methacrylate)

Abstract Radiation effects of poly (phenyl methacrylate) (PPMA) have been investigated by electron spin resonance (ESR) and Fourier Transform Infrared (FTIR) spectroscopy. The ESR spectrum observed for gamma irradiated PPMA at liquid nitrogen temperature (LNT) is a sextet (six line spectrum), while the spectrum appears to be broadened at room temperature (RT). Free radicals associated with the RT and LNT spectra are identified by the magnetic parameters employed to simulate the spectra. Thus, the ESR spectrum at LNT is found to be a superposition of components arising from the macroradicals of the type ∼CH2–Ċ(CH3)–CH2 ∼ (I) and a difference singlet spectrum due to phenoxy radicals C6H5[Odot] (II). The spectrum at RT is also simulated with the same values of magnetic parameters, employed to simulate the LNT spectrum, except for the value of the β-hyperfine splitting. Thus, the RT spectrum is thought to consist of two types of radicals I and II. The gradual decrease in intensity of the 1750 cm−1 FTIR absorp...