Crystallographic, morphological and photoluminescent investigations of Tb3+ -doped YAlO3 perovskites for lighting applications.

Terbium(III)-doped yttrium aluminate perovskite (YAP:xTb3+ ) (x = 0.01-0.08 mol) was synthesized using a simple gel-combustion method. Structural elucidations were performed using X-ray diffraction (XRD) and Rietveld analysis. Fourier-transform infrared spectral studies validated the efficient synthesis of designed doped samples. Transmission electron microscopic images showed the agglomerated irregular dimensions of the synthesized nanocrystalline materials. When excited at 251 nm, a strong emissive line attributed to 5 D4 → 7 F5 electronic transition was observed at 545 nm (green emission). The maximum luminescence was found at the optimized concentration (0.05 mol) of Tb3+ ions; this emission was quenched by dipolar-dipolar (d-d) interactions. Chromaticity (x and y) and correlated colour temperature parameters were obtained by analysing the emission profiles. Finally, the colour coordinates of nanophosphors were closer to the National Television Standards Committee green coordinates, which replicates their potency in the design and architecture of R-G-B-based white LEDs.

Mitochondrial Dysfunction in Arsenic-Induced Hepatotoxicity: Pathogenic and Therapeutic Implications.

Mitochondria are vital cellular organelles associated with energy production as well as cell signaling pathways. These organelles, responsible for metabolism, are highly abundant in hepatocytes that make them key players in hepatotoxicity. The literature suggests that mitochondria are targeted by various environmental pollutants. Arsenic, a toxic metalloid known as an environmental pollutant, readily contaminates drinking water and exerts toxic effects. It is toxic to various cellular organs; among them, the liver seems to be most affected. A growing body of evidence suggests that within cells, arsenic is highly toxic to mitochondria and reported to cause oxidative stress and alter an array of signaling pathways and functions. Hence, it is imperative to highlight the mechanisms associated with altered mitochondrial functions and integrity in arsenic-induced liver toxicity. This review provides the details of mechanistic aspects of mitochondrial dysfunction in arsenic-induced hepatotoxicity as well as various ameliorative measures undertaken concerning mitochondrial functions.

N-Acetylcysteine Reverses Monocrotophos Exposure-Induced Hepatic Oxidative Damage via Mitigating Apoptosis, Inflammation and Structural Changes in Rats.

Oxidative stress-mediated tissue damage is primarily involved in hepatic injuries and dysfunctioning. Natural antioxidants have been shown to exert hepatoprotective, anti-inflammatory and antiapoptotic properties. The present study evaluated the effect of N-acetylcysteine (NAC) against monocrotophos (MCP) exposure-induced toxicity in the rat liver. Albino Wistar rats were divided into four groups: (1) control, (2) NAC-treated, (3) MCP-exposure, (4) NAC and MCP-coexposure group. The dose of MCP (0.9 mg/kg b.wt) and NAC (200 mg/kg b.wt) were administered orally for 28 days. Exposure to MCP caused a significant increase in lipid peroxidation, protein oxidation and decreased glutathione content along with the depletion of antioxidant enzyme activities. Further MCP exposure increased pro-inflammatory cytokines levels and upregulated Bax and Caspase-3 expressions. MCP exposure also caused an array of structural alternations in liver tissue, as depicted by the histological and electron microscopic analysis. Thepretreatment of NAC improved glutathione content, restored antioxidant enzyme activities, prevented oxidation of lipids and proteins, decreased pro-inflammatory cytokines levels and normalized apoptotic protein expression. Treatment of NAC also prevented histological and ultrastructural alternations. Thus, the study represents the therapeutic efficacy and antioxidant potential of NAC against MCP exposure in the rat liver.

Physiological studies of native cyanobacterial species Lyngbya contorta and Phormidium foveolarum in sewage waste water.

A variety of Cyanobacterial species predominantly ensheathed forms occurs in sewage water receiving areas. A study was conducted to analyse the potential of using native Lyngbya contorta and Phormidium foveolarum isolated from sewage water irrigated soils, for biomass production under sewage waste water. The native Cyanobacterial strains were characterised and changes in their biochemical composition in response to different concentrations of sewage waste water were investigated. Results showed that biomass(3.5-6.6 mg 10 ml⁻¹, 2.6-5.6 mg 10 ml⁻¹) and photosynthetic pigment contents increased with incubation time (chlorophyll 1.21-3.09 µg ml⁻¹, 1.92-9.51 µg ml⁻¹; carotenoid 20.8-34.8 µg ml⁻¹, 16.4-32.8 µg ml⁻¹) and decreased thereafter as nutrients became limiting. On the other hand, soluble proteins, after showing a decline, recovered faster with maximum concentration (42.6-63.3 µg ml⁻¹ and 59-79.8 µg ml⁻¹) recorded on day 8. Total carbohydrate content also increased (19.27-31.45 µg ml⁻¹, 14.1-28.21 µg ml⁻¹) in response to various concentrations of sewage waste water. The overall response was better for 50% sewage waste water concentration which showed that these native strains were suitable candidates for cultivation after proper dilution.