Sahyadri Science College

Shimoga, India

Sahyadri Science College

Shimoga, India

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Karthikeyan J.,Sathyabama University | Naik P.P.,Sahyadri Science College | Nityananda Shetty A.,National Institute of Technology Karnataka
Environmental Monitoring and Assessment | Year: 2011

4-[N,N-(Dimethyl)amino]benzaldehyde thiosemicarbazone (DMABT) is proposed as an analytical reagent for the extractive spectrophotometric determination of copper(II). DMABT forms yellow colored complex with copper(II) in the pH range 4.4-5.4. Beer's law is obeyed in the concentration range up to 4.7 μg mL -1. The optimum concentration range for minimum photometric error as determined by Ringbom plot method is 1.2-3.8 μg mL-1. The yellowish Cu(II)-DMABT complex shows a maximum absorbance at 420 nm, with molar absorptivity of 1.72 × 104dm3 mol-1 cm-1 and Sandell's sensitivity of the complex obtained from Beer's data is 0.0036 μg cm-2. The composition of the Cu(II)-DMABT complex is found to be 1:2 (M/L). The interference of various cations and anions in the method were studied. Thus the method can be employed for the determination of trace amount of copper(II) in water, alloys and other natural samples of significant importance. © 2010 Springer Science+Business Media B.V.


Parameshwara P.,Sahyadri Science College | Shetty A.N.,National Institute of Technology Karnataka
Environmental Monitoring and Assessment | Year: 2011

p-[N,N-bis(2-chloroethyl)amino]benzaldehyde thiosemicarbazone (CEABT) is proposed as a new, sensitive, and selective analytical reagent for the spectrophotometric determination of palladium(II). The reagent reacts with palladium(II) in the pH range 1-2 to form a yellow-colored complex. Beer's law is obeyed in the concentration range up to 2.64 μg cm-3. The optimum concentration range for minimum photometric error as determined by Ringbom's plot method is 0.48-2.40 μg cm-3. The yellowish Pd(II)-reagent complex shows a maximum absorbance at 395 nm, with molar absorptivity of 4.05 × 104 dm3 mol-1 cm-1 and Sandell's sensitivity of the complex from Beer's data, for D= 0.001, is 0.0026 μg cm-2. The composition of the Pd(II)-CEABT reagent complex is found to be 1:2 (M-L). The interference of various cations and anions in the method were studied. The proposed method was successfully used for the determination of Pd(II) in alloys, catalysts, complexes, water samples, and synthetic alloy mixtures with a fair degree of accuracy. © 2010 Springer Science+Business Media B.V.


Sangeetha Gowda K.R.,Kuvempu University | Bhojya Naik H.S.,Kuvempu University | Vinay Kumar B.,Kuvempu University | Sudhamani C.N.,Kuvempu University | And 3 more authors.
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2013

New metal complexes of the type [M(nih)(L)](PF6) n·xH2O and [M(nih)2](PF 6)·xH2O (where M = Co(III) or Ni(II), L = 1,10-phenanthroline (phen)/or 2,2′ bipyridine (bpy), nih = 2-hydroxy-1-naphthaldehyde isonicotinoyl hydrazone, n = 2 or 1 and x = 3 or 2) have been synthesized and characterized by elemental analysis, magnetic, IR and 1H NMR spectral data. The electronic and magnetic moment 2.97-3.07 B.M. data infers octahedral geometry for all the complexes. The IR data reveals that Schiff base (nih) form coordination bond with the metal ion through azomethine-nitrogen, phenolic-oxygen and carbonyl-oxygen in a tridentate fashion. In addition, DNA-binding properties of these six metal complexes were investigated using absorption spectroscopy, viscosity measurements and thermal denaturation methods. The results indicated that the nickel(II) complex strongly bind with calf-thymus DNA with intrinsic DNA binding constant Kb value of 4.9 × 104 M-1 for (3), 4.2 × 10 4 M-1 for (4), presumably via an intercalation mechanism compared to cobalt(III) complex with Kb value of 4.6 × 10 4 M-1 (1) and 4.1 × 104 M-1 (2). The DNA Photoclevage experiment shows that, the complexes act as effective DNA cleavage agent. © 2012 Elsevier B.V. All rights reserved.


Reddy S.,Kuvempu University | Kumara Swamy B.E.,Kuvempu University | Chandra U.,Kuvempu University | Sherigara B.S.,Kuvempu University | Jayadevappa H.,Sahyadri Science College
International Journal of Electrochemical Science | Year: 2010

Cadmium oxide (CdO) nanoparticles were prepared using cetyl trimethyl ammonium bromide (CTAB) as surfactant by co-precipitation method, in which cadmium sulphate (CdSO4) was reacted with sodium hydroxide (NaOH) in the presence of acetic acid, ethanol, CTAB, at room temperature, then thermally treated at 400°C for 4 hours and the obtained product are analyzed by X-ray diffractometer (XRD), the average size of CdO nanoparticles found to be 47.8nm, UV-visible absorption spectra for CdO nanoparticles shows evidence of quantum size effect and compare with bare carbon paste electrode(BCPE), CdO nanoparticles modified carbon paste electrode(MCPE) shows enhanced peak current and exhibited excellent electrocatalytic activity towards oxidation of dopamine(DA) and ascorbic acid (AA) in acetate buffer solution at pH 6.5. © 2010 by ESG.


Yallappa S.,Kuvempu University | Manjanna J.,Kuvempu University | Sindhe M.A.,Kuvempu University | Satyanarayan N.D.,Kuvempu University | And 2 more authors.
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2013

Terminalia arjuna (T. arjuna) bark extract is used to reduce Cu 2+ → Cu0 under microwave irradiation. The formation of copper nanoparticles (CuNPs) is monitored by recording the UV-Vis absorption spectra for surface plasmon resonance (SPR) peak, ∼535 nm. The intensity of SPR increased linearly with increasing temperature of the reaction mixture. The formation mechanism of CuNPs is supported by the observed marginal decrease in pH and an increase in solution potential (E) of the reaction mixture. X-ray diffraction (XRD) pattern of the CuNPs agrees with the reported data for Cu metal and the crystallite size is ∼23 nm. Fourier transform infrared spectroscopy (FT-IR) and solid-state 13C NMR shows the presence of plant residues on the CuNPs, i.e., in situ bio-capping is possible by this method. Thermo gravimetric (TG) analysis shows the thermal degradation of plant residue and the conversion of Cu to CuO. Field emission electron microscopic (FESEM) image shows uniform spherical particles obtained here. Elemental analysis by energy dispersive X-ray (EDX) analysis confirms the presence of Cu alone, as expected. The in vitro antimicrobial activity is found to be effective for CuNPs dried at RT when compared to CuNPs dried at 70 C. In addition, CuNPs shows very good antioxidant property. © 2013 Elsevier B.V. All rights reserved.


Parameshwara Naik P.,Sahyadri Science College | Nityananda Shetty A.,National Institute of Technology Karnataka
Environmental Monitoring and Assessment | Year: 2010

4-[N,N-(Diethyl)amino] benzaldehyde thiosemicarbazone (DEABT) is proposed as an analytical reagent for the spectrophotometric determination of platinum(IV). The DEABT forms 1:2 yellow complex with Pt(IV), which is sparingly soluble in water and completely soluble in water-ethanol-DMF medium. The Pt(IV)-DEABT complex shows maximum absorbance at 405 nm. Beer's law is valid up to 7.80 μg cm-3, and optimum concentration range for the determination of platinum(IV) is 0.48-7.02 μg cm-3. The molar absorptivity and Sandell's sensitivity of the method are found to be 1.755 × 104 dm3 mol-1 cm-1 and 0.0012 μg cm-2, respectively. The relative error and coefficient of variation (n=6) for the method does not exceed ±0.43% and 0.35%, respectively. Since the method tolerates a number of metal ions commonly associated with platinum, it can be employed for the determination of platinum in environmental samples, pharmaceutical samples, alloys, catalysts, and complexes. The method is rapid as the Pt(IV)-DEABT complex is soluble in water-ethanol-DMF medium and not requiring any time consuming extraction method for the complex. © 2010 Springer Science+Business Media B.V.


Sreekanth B.,Acharya Institute of Technology | Krishnamurthy G.,Sahyadri Science College | Naik H.S.B.,Kuvempu University | Vishnuvardhan T.K.,Acharya Institute of Technology
Nucleosides, Nucleotides and Nucleic Acids | Year: 2012

The two new metal complexes of Cu(II) and Mn(II) containing macroacyclic ligand of the type [Cu(hpn)](PF6)2 (1) and [Mn(hpn)](PF6)2 (2) [where hpn = [1-{[2-{[2-hydroxynaphthalen-1-yl)methylidine]amino}phenyl)imino]methyl} naphthalene-2-ol]] have been synthesized and characterized by employing analytical and spectral methods. The DNA binding properties of the complexes with calf thymus-DNA were studied by using absorption spectra and viscosity measurements, as well as thermal denaturation experiments. The absorption spectra indicated that the complexes intercalate tightly between the base pairs of the DNA with intrinsic DNA binding constants of 1.8 10 4 M 1 for (1) and 3.7 10 4 M 1 for (2) in 5 mM Tris-HCl/50 mM NaCl buffer at pH 7.2, respectively. The enhancement in the relative viscosity of DNA on binding to the ligand supports the proposed DNA binding modes. The oxidative cleavage activity of complexes (1) and (2) were carried out on double-stranded pUC19 circular plasmid DNA using gel electrophoresis. The complexes show significant nuclease activity. © 2012 Copyright Taylor and Francis Group, LLC.


Gunaga S.,University of Agricultural Sciences, Dharwad | Rajeshwari N.,Sahyadri Science College | Vasudeva R.,University of Agricultural Sciences, Dharwad
Tropical Ecology | Year: 2012

A comparative description of tree diversity of community-protected kaan forests and state-managed reserve forests influenced by the level of disturbance and rainfall was assessed in Sagar taluk, Shimoga district, Karnataka, India. Kaan forests and state-managed reserve forests in regions of high and low rainfall were assessed for tree diversity. In each sampled site, a transect of 1 km and two 25 m2 regeneration quadrats were laid. Kaan forests possessed a higher species richness, with 85 tree species, than the reserve forests (57). Basal area and tree density were also higher in the kaan forests, although the difference was only marginal in some instances. Richness of endemic, rare, endangered and threatened species, as well as species of medicinal or economic importance, was higher in the kaan forests than in the reserve forests. The total number of species, and the number of evergreen species, were negatively correlated with the level of disturbance. Further, with increased disturbance, the number of rare, endangered and threatened species also decreased, as did the number of endemics. © International Society for Tropical Ecology.


Reddy S.,Kuvempu University | Kumara Swamy B.E.,Kuvempu University | Vasan H.N.,Indian Institute of Science | Jayadevappa H.,Sahyadri Science College
Analytical Methods | Year: 2012

Present work describes the characterization of commercially available ZnO and its electrochemical investigation of dopamine in the presence of ascorbic acid. ZnO was characterized by powder XRD, UV-visible absorption, fluorescence, infrared spectroscopy and scanning electron microscopy. The carbon paste electrode was modified with ZnO and ZnO/polyglycine for further electrochemical investigation of dopamine. The modified electrode shows good electrocatalytic activity towards the detection of dopamine with a reduction in overpotential. The ZnO/polyglycine modified carbon paste electrode (CPE/ZnO/Pgl) shows excellent electrochemical enhancement of peak currents for both dopamine (DA) and ascorbic acid (AA) and for simultaneous detection of DA in the presence of high concentrations of AA with 0.214 V oxidation peak potential differences between them at pH 7.4. From the scan rate variation and concentration, the oxidation of DA and AA was found to be adsorption-controlled. The use of CPE/ZnO/Pgl is demonstrated for the detection of DA in blood serum and injection samples. This journal is © The Royal Society of Chemistry 2012.


Reddy S.,Kuvempu University | Kumara Swamy B.E.,Kuvempu University | Jayadevappa H.,Sahyadri Science College
Electrochimica Acta | Year: 2012

In the present work, different shaped CuO nanoparticles were synthesized using cetyl trimethyl ammonium bromide (CTAB) and sodium dodecyl sulfate (SDS) in a co-precipitation method. The CuO nanoparticles were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), infrared absorption spectroscopy (IR) and UV-visible absorption spectroscopy (UV-vis). The prepared CuO nanoparticles were used for the preparation of modified carbon-paste electrodes (MCPE) for the electrochemical detection of dopamine (DA) at pH 6.0. The MCPE prepared from flake-shaped CuO nanoparticles exhibited an enhanced current response for DA. Electrochemical parameters, such as the surface area of the electrode, the heterogeneous rate constant (k s) and the lower detection limit (5.5 × 10 -8 M), were calculated and compared with those of the MCPE prepared from rod-shaped CuO nanoparticles. The MCPE prepared from SDS/polyglycine/flake-shaped CuO nanoparticles exhibited a further improved current response for DA and a high selectivity (E AA - E DA = 0.28 V) for the simultaneous investigation of DA and ascorbic acid (AA) at pH 6.0. The modified carbon-paste electrochemical sensors were compared, and the MCPE prepared from SDS/polyglycine/flake-shaped CuO nanoparticles exhibited better performance than the MCPE prepared from CTAB/polyglycine/flake-shaped CuO nanoparticles. © 2011 Elsevier Ltd.

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