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Author: search.filters.author.Bhuvaneshwari VHas files: Yes

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    INFLUENCE OF GADOLINIUM DOPED IN NICKEL NANOFERRITES ON STRUCTURAL, OPTICAL, ELECTRICAL, AND MAGNETIC PROPERTIES
    (Elsevier, 2023-02) Bhuvaneshwari V; Lenin N; Shiva C; Kathirvel M; Ragavendran V; Rajeshwari A; Guruprakash B; Vinoth Kumar G.G
    The sonochemical reaction approach was used to make NiGdxFe2-xO4 nanoferrites (x = 0.01, 0.03, 0.05, 0.07, and 0.09). X-ray diffraction (XRD), ultra violet-diffuse reflectance spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, vibrating sample magnetometer, and electrochemical impedance spectroscopy were used to investigate the optical, magnetic, electrical, and structural properties of NiGdxFe2-xO4 nanoferrites. The creation of a cubic spinel structure was confirmed by analyzing the XRD pattern of these NiGdxFe2-xO4 nanoferrites. The average crystallite diameters of the nanoparticles for the compositions x = 0.01, 0.03, 0.05, 0.07, and 0.09 were 57, 53, 48, 45, and 41 nm, respectively. To investigate the dielectric behavior of the produced nanoferrites, an impedance study was performed. The addition of Gd to NiFe2-xO4 nanoparticles increased the dielectric characteristics of the produced nanoferrites, according to characterization experiments. A cation distribution has been proposed for the determination of various important theoretical parameters for these samples. The addition of Gd3+ nanoparticles has shown the ferromagnetic behavior at room temperature confirmed by VSM analysis. A specific correlation between magnetic interaction and lattice strain was observed in Gd3+ substituted nickel ferrite. An increase in Gd concentration in the manufactured nanoferrites resulted in a rise in saturation magnetization and a decrease in coercivity.
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    DUAL SPECIFIC PROTEIN KINASES MEDIATE NEEM FRUIT EXTRACT-INDUCED DEFENSE GENE EXPRESSION IN SOLANUM LYCOPERSICUM L.
    (Elsevier, 2023-04) Bhuvaneshwari V; Paul P.K
    The molecular aspects of interaction between botanical extracts and plant cells through Mitogen-Activated Protein Kinase (MAPK) signaling cascades leading to the expression of defense genes are not well understood. The current study aims to better understand the role of dual-specific protein kinases in inducing defense gene expression in tomato as a result of aqueous neem fruit extract treatment.Staurosporine, Lavendustin A and K252a were used as kinase regulators which may modify the neem fruit extract induced MAPK cascades followed by defense gene expression in tomato plants. Tomato plants raised under aseptic conditions were treated either with neem fruit extract alone and pretreatment with either any one of the above kinase pathway inhibitors. Cytoplasmic defense proteins like PAL, TAL, and POX were studied for their activities and gene expression.. The differential reverse transcriptase-quantitative polymerase chain reaction (RT-qPCR) approach using mRNA extracted after treatment in all the groups was done for analyzing relative gene expression of PAL, POX and MAPKs, MAPKKs, MAPKKKs. The results demonstrated that neem fruit extract induced TAL and POX enzyme activities were inhibited by Staurosporine, Lavendustin A and K252a whereas PAL activities were inhibited by K252a only and superinduced by the pretreatment of Staurosporine or Lavendustin. Some of the neem fruit extract induced cytoplasmic and cell wall bound specific isoPOX proteins were inhibited by Lavendustin A / K252a, but Staurosporine could either inhibit / partially inhibit /superinduce them.. RT-qPCR analysis revealed that induction of gene expressions by neem treatment significantly inhibited the PAL, POX, all 3MAPKs, all 3 MAPKKKs, MAPKK1, MAPKK2, MAPKK3, MAPKK5 in plants pretreated with Lavendustin A and K252a but not by Staurosporine. Since Staurosporine can both activate and inhibit serine/threonine kinases our results indicate that staurosporine pretreatment in tomato plants treated with neem fruit extract leads to inhibition of TAL, POX activity, partial inhibition of cytoplasmic POX proteins, superinduction of PAL activity, cytoplasmic and cell wall bound POX proteins, their genes and MAPK cascade gene expression. The involvement of tyrosine kinases was confirmed by the inhibition of MAPK3, MAPKKs, defense gene and proteins by Lavendustin. Results indicate the expression of defense genes and enzymes in cytoplasm and cell wall by the neem fruit extract through the involvement of dual specific serine/threonine/Tyr (STY) kinases such as MAPK3, MAPKKs leading to establishment of signaling cascade.