M. D. Uplane

Bio: M. D. Uplane is an academic researcher from Savitribai Phule Pune University. The author has contributed to research in topics: Thin film & Crystallite. The author has an hindex of 21, co-authored 75 publications receiving 1567 citations. Previous affiliations of M. D. Uplane include College of Engineering, Pune & Shivaji University.

Studies on structural, optical and electrical properties of boron doped zinc oxide films prepared by spray pyrolysis technique

Abstract: Boron doped and undoped zinc oxide (ZnO) thin films were prepared by pyrolytic decomposition of methanolic solution of zinc acetate onto glass substrates. The structural properties of the films were studied by using X-ray diffraction. The results show that both the boron doped and undoped films exhibit hexagonal wurtzite structure with strong c-axis orientation as evidenced by X-ray diffraction patterns. The crystallite size wanes with increasing doping concentration. The electrical resistivity studies were carried out using the four-probe method. It is found that the films with 0.8 wt% boron doping concentration attains the lowest resistivity (10−4 Ω m), whereas for higher and lower doping concentrations resistivity increases. The thermoelectric power studies showed that the doped and undoped films exhibit n-type conductivity, optical studies revealed that with increase in doping concentration the transmittance of the film increases in the wavelength range 400–600 nm. The optical absorption data were used to determine band gap energy and it is found to be 3.22 eV for undoped ZnO films and 3.32 for boron doped films.

H2S gas sensing properties of nanocrystalline Cu-doped ZnO thin films prepared by advanced spray pyrolysis

Abstract: The ZnO-based thin films doped with 1–4 wt% Cu were deposited on the glass substrates using the advanced spray pyrolysis technique. All films are deposited at 473 K. The crystallinity and morphology of the films were characterized by XRD, TEM and FE-SEM respectively. The structural analyses of the films indicate that they are polycrystalline and have a hexagonal wurtzite structure; however Cu doping enhances the preferential orientation along the [0 0 2]. The energy dispersive X-ray spectroscopic analysis (EDX) confirmed an enhancement in the amount of Cu in the film with increase in the copper concentration in the starting solution. The sensor response was estimated by the change in the electrical conductance of the film in the absence and presence of H2S gas. The sensor response and selectivity in relation to, operation temperature, Cu doping concentration and the gas concentration has been systematically studied. A significant response (∼0.38) towards 20 ppm H2S at 523 K operating temperature is observed for the 4 wt% Cu-doped ZnO. The Pd-sensitized 4 wt% Cu doped ZnO film exhibits improved sensing characteristics with good stability.

Controlled release of biologically active silver from nanosilver surfaces

Abstract: Major pathways in the antibacterial activity and eukaryotic toxicity of nanosilver involve the silver cation and its soluble complexes, which are well established thiol toxicants. Through these pathways, nanosilver behaves in analogy to a drug delivery system, in which the particle contains a concentrated inventory of an active species, the ion, which is transported to and released near biological target sites. Although the importance of silver ion in the biological response to nanosilver is widely recognized, the drug delivery paradigm has not been well developed for this system, and there is significant potential to improve nanosilver technologies through controlled release formulations. This article applies elements of the drug delivery paradigm to nanosilver dissolution and presents a systematic study of chemical concepts for controlled release. After presenting thermodynamic calculations of silver species partitioning in biological media, the rates of oxidative silver dissolution are measured for nan...

The Effects of Cadmium Toxicity

Abstract: Cadmium (Cd) is a toxic non-essential transition metal that poses a health risk for both humans and animals. It is naturally occurring in the environment as a pollutant that is derived from agricultural and industrial sources. Exposure to cadmium primarily occurs through the ingestion of contaminated food and water and, to a significant extent, through inhalation and cigarette smoking. Cadmium accumulates in plants and animals with a long half-life of about 25–30 years. Epidemiological data suggest that occupational and environmental cadmium exposure may be related to various types of cancer, including breast, lung, prostate, nasopharynx, pancreas, and kidney cancers. It has been also demonstrated that environmental cadmium may be a risk factor for osteoporosis. The liver and kidneys are extremely sensitive to cadmium’s toxic effects. This may be due to the ability of these tissues to synthesize metallothioneins (MT), which are Cd-inducible proteins that protect the cell by tightly binding the toxic cadmium ions. The oxidative stress induced by this xenobiotic may be one of the mechanisms responsible for several liver and kidney diseases. Mitochondria damage is highly plausible given that these organelles play a crucial role in the formation of ROS (reactive oxygen species) and are known to be among the key intracellular targets for cadmium. When mitochondria become dysfunctional after exposure to Cd, they produce less energy (ATP) and more ROS. Recent studies show that cadmium induces various epigenetic changes in mammalian cells, both in vivo and in vitro, causing pathogenic risks and the development of various types of cancers. The epigenetics present themselves as chemical modifications of DNA and histones that alter the chromatin without changing the sequence of the DNA nucleotide. DNA methyltransferase, histone acetyltransferase, histone deacetylase and histone methyltransferase, and micro RNA are involved in the epigenetic changes. Recently, investigations of the capability of sunflower (Helianthus annuus L.), Indian mustard (Brassica juncea), and river red gum (Eucalyptus camaldulensis) to remove cadmium from polluted soil and water have been carried out. Moreover, nanoparticles of TiO2 and Al2O3 have been used to efficiently remove cadmium from wastewater and soil. Finally, microbial fermentation has been studied as a promising method for removing cadmium from food. This review provides an update on the effects of Cd exposure on human health, focusing on the cellular and molecular alterations involved.