Table of Contents - Volume 11 Number 1

Pyrolyzed carbon micro/nano-structures have great potential as functional units in biosensors where biofunctionalization of the carbon surface is a requisite. In this work, we present a comparison of four different oxidation pretreatments, i.e. vacuum ultraviolet (VUV), electrochemical activation (EA), oxygen reactive ion etching (RIE), and ultraviolet/ozone (UV/O3) pretreatments on pyrolyzed carbon surface. X-ray photoelectron spectroscopy (XPS) results indicated that all the oxidation techniques except UV/O3 pretreatment yielded identical oxidation levels. The percentage of the carboxyl group which is suitable for covalent attachment of amine terminated biomolecules increased with pretreatment time, and was highest in the case of VUV pretreatment (15%) followed by oxygen RIE (12.5%) and EA pretreatments (12.5%) and UV/O3 pretreatment showed significantly lower carboxyl group percentage at 6%. This study helps to optimize the surface functionalization conditions for covalent binding of bioreceptors on the pyrolyzed carbon substrate for biosensing applications.

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Molybdenum-zinc substituted hexaferrites were synthesized by high-energy ball milling and subsequent sintering at different temperatures (1100, 1200, and 1300° C). The samples sintered at 1100° C exhibited good hard magnetic properties, although a decrease in saturation magnetization from 70.2 emu/g for the unsubstituted sample down to 57 emu/g for the sample with x = 0.3 was observed. The drop in saturation magnetization results mainly from the presence of secondary nonmagnetic oxides. The samples sintered at temperatures ≥1200° C showed an improvement in saturation magnetization, and a sharp drop in coercivith. This behavior was associated with the development of the W-type hexaferrite, the particle growth, and possibly the spin reorientation transition from easy-axis to easy-plane.

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Carbon doped Aluminium Nitride (C-AlN) thin film was synthesized on Al and Cu substrates using RF sputtering and used as heat sink for high power LED. The optical properties of LED such as correlated color temperature (CCT) and brightness (LUX) was recorded by spectrometer and tested for various driving currents. Increased lux level was observed for high driving currents and showed the performance C-AlN thin film as good thermal interface material at high driving currents.The observed CCT values were in between 6180-6900 K and increased for high driving currents. At the lower driving current, CCT value was high for C-AlN on Cu than on Al.overall, the observed optical properties of LED using C-AlN thin film as thermal interface material was suggested to explore the usage of C doped AlN thin film as effective thin film thermal interface material for thermal management in solid state lighting applications.

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This article describes the synthesis of ZnO nano particle with an average crystallite size ~20 nm through aqueous solution growth technique using Benzyltrimethylammoium hydroxide Ionic liquid (BTMAH) as a structure directing agent. Crystallinity, phase purity, Volume of unit cell, average crystallite size, and strain were confirmed by X-ray diffraction pattern using Scherrer‟s method and Williamson-Hall analysis, particle morphology and grain size were confirmed by Atomic force microscopy. Using the optical properties photo luminescence, interaction between ammonia gas and zinc oxide nanoparticle were also investigated. The material shows average significant increment in the PL intensity which conform its tremendous applicability in optical gas sensor to detect ammonia gas (25 ppm).

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Al₂O₃powder with various particle sizes was prepared by milling process and mixed together with epoxy resin in order to increase the thermal conductivity of resin and decrease the junction temperature of the LEDs. Al₂O₃ powder filled epoxy resin was applied as thermal interface material (TIM) for an effective system level analysis of thermal transient measurement. The result depicted that the milled Al₂O₃ powder for 3 hour powder showed the highest thermal conductivity and hence lower in thermal resistance of LED. Moreover, the driving currents also influence the thermal resistance and achieved low thermal resistance when measured at 350mA. The thermal properties of the sample were tested using t3ster. The surface morphology of the samples was tested using FESEM.

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Polymorphism is a widespread and commonly occurring phenomenon in fields of chemistry, biology and materials science. In recent years, the development of technology has lead to the development of different instrumentation tools(such as SXRD, PXRD, IR, NMR, AFM) which are employed for the characterization of different polymorphic materials (namely polymers, nano crystalline metal oxides and pharmaceutical drugs) which are of great importance because of their applications in the field of materials science.

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Metal complxes of Glimeperide drugs were prepared and characterized based on elemental analysis, FT-IR, Molar conductance and thermal analysis (TGA and DTG) technique. From elemental analysis data, the complexes were proposed to have general formulae (GLM)₂Co2H₂O, (GLM)₂Cu, (GLM)₂Zn,and (GLM)₂La2H₂O. The molar conductance data reveal that all the metal complexes are non-electrolytic, IR spectra shows that GLM are coordinated to metal ions in a neutral bidentate manner from the ESR spectra and XRD-spectra. It is found that the geometrical structures of these complexes are tetrahedral Cu(II) ,Zn(II) and octrahedral Co(II), La(II). The thermal behavior of these complexesstudied using thermogravimetric analysis (TGA and DTG) techniques. The results obtained shows that the hydrated complexes lose water molecules of hydration followed immediately by decomposition of the anions and ligand molecules in the successive unseparate steps.

Thermogravimetric analysis was carried out to study the decomposition and various kinetic parameters. Freeman Carroll and Sharp Wentworth method have been applied for calculation of kinetic parameters. While data from freeman Carroll method have been used to determine various thermodynamic parameters such as order of reactions, energy of activation, frequency factor, entropy change, free energy change and apparent entropy change and order of reaction..

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Copper (II) reacts with HCPFPBH and forms buff coloured precipitate insoluble in many organic solvents like absolute alcohol, ether, benzene, chloroform etc. The Solid complex has molecular formula (C₁₉H₁₃N₂OFCl)₂Cu which melts at 202⁰C with decomposition. The infrared spectra of the complex was recorded in the range 4000-450cm^-1. The ligand molecule consists of a weak band at 2550 cm^-1. This confirms the presence of azomethine nitrogen in the ligand. This band is absent in the IR Spectrum of the complex confirming the involvement of this group in complexation . The strong band of the ligand at 1640 cm^-1 is due to C = NH⁺ group which shifts to lower frequency by 60 cm^-1. This confirms the formation of C = N -----Cu bond. The N – O stretching mode shifts to higher frequency from 930 cm^-1 to 960 cm^-1 this confirms the formation of N – O – Cu bond by replacement of N – O – H proton by Copper.Cu – N band appears at 460 cm^-1 which supports the formation of Cu – N bond. The positive value of volume susceptibility confirms that the complex is paramagnetic. TGA studies suggest that complex is thermally stable upto 202⁰C and melts with decomposition. At this temperature water molecules are absent which is also suggested by IR spectra of the complex. These studies support the use of N-Hydroxy-N-(4-Chloro) phenylN’-(4-Fluoro) phenyl benzamidine hydrochloride for gravimetric determination of Copper (II) in ores and alloys.

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An isocratic, reversed phase-liquid-chromatographic method was developed for the quantitative determination of Levofloxacin and Cefpodoxime proxetil in combined-dosage form. Alliance -Waters System with Agilant Zorbax Eclipse XBD-C8, (150mm×4.6; 5µm) column with mobile phase containing water with Ortho phosphoric acid: Methanol in the ratio of (80: 20, v/v) was used. The flow rate was 0.5 ml/min, column temperature was 40°C and effluents were monitored at 270 nm. The retention times of Levofloxacin and Cefpodoxime proxetil were 3.096min and 4.559min, respectively. The correlation co-efficient for Levofloxacin and Cefpodoxime proxetil was found to be 1.0 and 1.0, respectively. The proposed method was validated with respect to linearity, accuracy, precision, specificity, and robustness. Recovery of Levofloxacin and  Cefpodoxime proxetil in formulations was found to be in the range of 97-103% and 97-103% respectively confirms the non-interferences of the excipients in the formulation. Due to its simplicity, rapidness and high precision. The method was successfully applied for the estimation of Levofloxacin and Cefpodoxime proxetil in combined dosage form.

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The present paper deals with the study of sulphonylurea glipizide (GLP) drug in order to give a thought concerning its coordinating potentiality towards some inner transition metals. Metal complex of GLP drug issynthesized and characterized by using analytical data, molar conductance, X-ray diffraction and thermogravimetric analysis (TGA and DTA) studies. From the analytical data, the complex is proposed to have general formula(C₂₁H₂₆N₅O₄S)₂Sm(OH₂)₄.Low values of molar conductance indicate that complex have non ionic nature. The conductometric titration using monovariation method reveal that complexis L₂M type which is further confirmed by Job’s method of continuous variation as modified by Turner and Anderson. Geometery of complex is assigned to be hexagonal in which ligand molecules lie horizontally joining the central metal atomand four water molecules attached vertically and horizontally with the metal, supported by spectroscopic study. Powder X-ray diffraction data have been used to calculate particle size, porosity, volume of unit cell and density of synthesized complex.The thermal decomposition of complex is studied using thermogravimetric (TGA) and differential thermal analysis (DTA) techniques. The kinetic parameters such as, energy of activation (E_a), enthalpy (ΔH), entropy (ΔS) and free energy change (ΔG) of the complexis evaluated by employing the Freeman-Carroll and Sharp-Wentworth methodsand the relative thermal stability of the complexisalso discussed. 

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A  series of thiourea ligand , N-N'- diphenyl thiourea [I] [DPTH], N-phenyl-N'-[2-phenoyl] thiourea [II] [PPTH], N-phenyl-N'-[2-chlorophenyl] thiourea III [PCPTH], N-phenyl-N'-  [5-chloro-2-methyl phenyl]  thiourea IV [PCMPTH] and N- phenyl -N'-(5-chloro-2-methoxy phenyl) thiourea V (PCMTPTH) and their transition metal complexes of the type ML2 and ML2 Cl2  have been synthesized by reacting phenyl isothiocyanate with substituted aniline and transition metal salts. These newly synthesized ligands and their complexes were characterized by elemental and spectral studies. Based upon these studies it was revealed that in all the cases metal is coordinated through suphur group of thioamide of ligands. In case of nickel complexes, the nickel is coordinated to both oxygen and sulphur. In all the complexes metal is tetra coordinated forming a square planer geometry. 

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