Mother Teresa Women's University

Abstract: A rough set theory is a new mathematical tool to deal with uncertainty and vagueness of decision system and it has been applied successfully in all the fields. It is used to identify the reduct set of the set of all attributes of the decision system. The reduct set is used as preprocessing technique for classification of the decision system in order to bring out the potential patterns or association rules or knowledge through data mining techniques. Several researchers have contributed variety of algorithms for computing the reduct sets by considering different cases like inconsistency, missing attribute values and multiple decision attributes of the decision system. This paper focuses on the review of the techniques for dimensionality reduction under rough set theory environment. Further, the rough sets hybridization with fuzzy sets, neural network and metaheuristic algorithms have also been reviewed. The performance analysis of the algorithms has been discussed in connection with the classification.

Abstract: The aqueous beetroot extract was used as reducing agent for silver nanoparticles synthesis. The synthesized nanoparticles were characterized using UV-visible spectroscopy, X-ray diffraction (XRD) and transmission electron microscopy (TEM). The surface plasmon resonance peak of synthesized nanoparticles was observed at 438 nm. As the concentration of beetroot extract increases, absorption spectra shows blue shift with decreasing particle size. The prepared silver nanoparticles were well dispersed, spherical in shape with the average particle size of 15 nm. The prepared silver nanoparticles are effective in inhibiting the growth of both gram positive and gram negative bacteria. The prepared silver nanoparticles reveal faster catalytic activity. This natural method for synthesis of silver nanoparticles offers a valuable contribution in the area of green synthesis and nanotechnology avoiding the presence of hazardous and toxic solvents and waste.

Abstract: Synthesis of silver nanoparticles using leaf extract of Hibiscus cannabinus has been investigated. The influences of different concentration of H. cannabinus leaf extract, different metal ion concentration and different reaction time on the above cases on the synthesis of nanoparticles were evaluated. The synthesized nanoparticles were characterized using UV-vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and Transmission Electron Microscopy (TEM). The prepared silver nanoparticles were monodispersed, spherical in shape with the average particle size of 9 nm and shows surface plasmon peak at 446 nm. The study also reveals that the ascorbic acid present in H. cannabinus leaf extract has been used as reducing agent. The prepared silver nanoparticle shows good antimicrobial activity against Escherichia coli, Proteus mirabilis and Shigella flexneri.

Abstract: A rapid method for synthesis of silver nanoparticles using the leaf extracts of Caesalpinia coriaria that has high level of tannin contents is reported. For leaf extracts preparation, two methods were adopted and compared with their extracellular synthesis of metallic silver nanoparticles. Stable silver nanoparticles produced by treating an aqueous solution of AgNO3 (5 mM) with the leaf extracts as reducing agent of Ag+ to Ag0. The formation of the silver nanoparticles (AgNPs) in the reaction mixture was determined using the surface plasmon resonance band shown in UV–vis spectroscopy. To identify the active biomolecules responsible for the reduction of Ag+ ion and the stabilization of AgNPs synthesized the functional group available in C. coriaria leaf extracts (CCLE) was studied by Fourier transmission infrared (FT-IR) spectroscopy. The X-ray diffraction (XRD) analysis showed the crystalline structure of metallic silver ions. The energy dispersive X-ray spectroscopy (EDX) analysis of AgNPs was confirmed the presence of pure elemental silver ion with no other impurity peaks. The morphology and topography of the AgNPs were determined using field emission scanning electron microscopy (FESEM). The size of the silver nanoparticles was differed by the kind of leaf extracts used for synthesis. The morphology of the AgNPs synthesized using boiled leaf extracts was found to be triangle shape with diameter range from 40 nm to 52 nm whereas in the case centrifuged leaf extracts, three shapes viz., triangle, hexagonal and spherical were noticed with an average size between 78 nm and 98 nm. Furthermore the synthesized AgNPs were found to show potential antimicrobial activity against multidrug resistant Gram-positive (Escherichia coli and Pseudomonas aeruginosa) and Gram-negative (Klebsiella pneumoniae, and Staphylococcus aureus) clinically isolated human pathogens. The present results clearly indicated that the CCLE is a good nontoxic source for extracellular synthesis of AgNPs in eco-friendly way as compared to other methods. Thus C. coriaria leaf extracts provide a potential source for development of commercially important industrial products including cosmetics and nanomedicines by tagging nanoparticels with tannins in the future.

Abstract: The present study describes the role of zinc oxide nanoparticles (ZnONPs) in reversing oxidative stress symptoms induced by heavy metal (Cd and Pb) exposure in Leucaena leucocephala (Lam.) de Wit. Seedling growth was significantly enhanced with the augmentation of ZnONPs following Cd and Pb exposure. Heavy metal accumulations were recorded as 1253.1 mg Cd per kg DW and 1026.8 mg Pb per kg DW for the respective treatments. Results demonstrated that ZnONPs augmentation caused an increase in photosynthetic pigment and total soluble protein contents while a significant decrease in malondialdehyde (MDA-lipid peroxidation) content in leaves. Antioxidative enzymes such as superoxide dismutase (SOD), catalase (CAT) and peroxidase (POX) were, in turn, elevated in heavy metal-exposed leaves amended with ZnONPs. The ameliorating effect of ZnO nanoparticles on oxidative stress induced toxicity was also confirmed by the reduced MDA content and the elevated level of antioxidative enzyme activities in leaf tissues of L. leucocephala seedlings. Further, addition of ZnONPs in combination with Cd and Pb metals induced distinct genomic alterations such as presence of new DNA bands and/or absence of normal bands in the RAPD pattern of the exposed plants. This study uniquely suggests a potential role of zinc oxide nanoparticles in the remediation of heavy metal contaminated media.