Synthesis and Spectroscopy of Novel‐α‐Pyrazolylglycine Derivatives

The synthesis of α‐pyrazolylglycine derivatives(7a‐d) with different substituents, starting from glycine have been pre pared. The spectroscopy of intermediate compounds and the final amino acids have been discussed.     

Structure Breaking/Making Property of Acefylline Piperazine in Aqueous,Aqueous Methanol,and Aqueous Ethylene Glycol Systems

Densities of acefylline piperazine (AP) in aqueous, aqueous methanol, and aqueous ethylene glycol (10% v/v) systems are determined in the concentration range 0.04-0.14±0.001 mol/dm³ at different temperatures (298.15-318.15 K) with the interval of 5 K. The apparent molar volume (φv), the partial molar volume \((\phi_v^0)\), and the ion-ion interaction parameter (S_v) are calculated using the Masson equation. Partial molar expansibilities \((\phi_E^0)\), which indicate the presence or absence of the caging or packing effect, are also evaluated and discussed. The results are interpreted in terms of solute-solvent and solute-solute interactions of AP in aqueous, aqueous methanol, and aqueous ethylene glycol systems. The structure-breaking and structure-making properties of AP are inferred by the sign of Hepler′s criterion \((\partial^2\phi_v^0/\partial{T}^2)_p\), i.e. the second derivative of the partial molar volume with respect to the temperature at the constant pressure.     

Determination of lithium isotopic composition by thermal ionization mass spectrometry in seawater

The isotopic composition of lithium in seawater has been determined by thermal ionization mass spectrometry (TIMS) based on the use of lithium hydroxide as the ion source. Isotopic measurements in a reference material supplied by IAEA (L-SVEC Li₂CO₃) were made to check the reproducibility of the method and ⁶Li indicates mobilization of light isotope of lithium form the sediment.     

Tailoring the optical and magnetic properties of La-BaM hexaferrites by Ni substitution

We investigate the impact of Ni insertion on the structural,optical,and magnetic properties of Ba_0.8La_0.2Fe_12-xNi_xO₁₉hexaferrites(Ni substituted La-BaM hexaferrites).Samples were prepared using the conventional co-precipitation method and sintered at 1000℃for 4 hours to assist the crystallization process.An analysis of the structure of the samples was carried out using an x-ray diffraction(XRD)spectrometer.The M-type hexagonal structure of all the samples was confirmed using XRD spectra.The lattice parameters a and c were found to be in the ranges of 5.8925±0.001 nm–5.8952±0.001 nm and 23.2123±0.001 nm–23.2219±0.001 nm,respectively.The M-type hexagonal nature of the prepared samples was also indicated by the presence of corresponding FT-IR bands and Raman modes in the FT-IR and Raman spectra,respectively.EDX results confirmed the successful synthesis of the samples according to the required stoichiometric ratio.A UV-vis spectrometer was used to record the absorption spectra of the prepared samples in the wavelength range of 200 nm–1100 nm.The optical energy bandgap of the samples was found to be in the range of 1.21 eV–3.39 eV.The M–H loops of the samples were measured at room temperature at an applied magnetic field range of 0 kOe–60 kOe.A high saturation magnetization of 99.92 emu/g was recorded in the sample with x=0 at a microwave operating frequency of 22.2 GHz.This high value of saturation magnetization is due to the substitution of La3+ions at the spin-up(12k,2a,and 2b)sites.The Ni substitution is proven to be a potential candidate for the tuning of the optical and magnetic parameters of M-type hexaferrites.Therefore,we suggest that the prepared samples are suitable for use in magneto-optic applications.     

A sunlight-induced method for rapid biosynthesis of silver nanoparticles using an <Emphasis Type="Italic">Andrachnea chordifolia</Emphasis> ethanol extract

In this study a sunlight-induced method for rapid synthesis of silver nanoparticles using an ethanol extract of Andrachnea chordifolia is described. The silver nitrate solutions (1 mM) containing the ethanol extract of Andrachnea chordifolia were irradiated by both sunlight radiation and by sunlight radiation passed through different colored filters (red, yellow or green). The smallest size of silver nanoparticles was obtained when a silver ion solution was irradiated for 5 minutes by direct sunlight radiation. Further examination of the shape and size and of the surface chemistry of these biogenic silver nanoparticles, which were prepared under sunlight radiation, was carried out using transmission electron microscopy and infrared spectroscopy, respectively. Transmission electron microscopy images show spherical particles with an average size of 3.4 nm. Hydroxyl residues were also detected on the surface of these biogenic silver nanoparticles fabricated using plant extract of Andrachnea chordifolia under sunlight radiation. Our study on the reduction of silver ions by this plant extract in darkness shows that the synthesis process can take place under dark conditions at much longer incubations (48 hours). Larger silver polydispersed nanoparticles ranging in size from 3 to 30 nm were obtained when the silver ions were treated with the ethanol extract of Andrachnea chordifolia under dark conditions for 48 hours.     

Genotypic Variability Among Soybean Genotypes Under NaCl Stress and Proteome Analysis of Salt-Tolerant Genotype

The present investigation was conducted to evaluate salt tolerance in ten genotypes of soybean (Glycine max L.). Twelve-day-old seedlings, grown hydroponically, were treated with 0, 25, 50, 75, 100, 125 and 150?mM NaCl for 10?days. Growth, lipid peroxidation and antioxidant enzyme activities were evaluated. Growth, measured in terms of length, fresh weight and dry weight of plants, was drastically reduced in Pusa-24 while there was little effect of NaCl treatment on Pusa-37 genotype of soybean. High level of lipid peroxidation was observed in Pusa-24 as indicated by increased level of malondialdehyde. Activities of superoxide dismutase, catalase, ascorbate peroxidase and glutathione reductase were maximum in Pusa-37 where 9-, 1-, 5- and 6-fold increase over control were observed, respectively. The results suggested that Pusa-24 and Pusa-37 are salt-sensitive and salt-tolerant genotype of soybean, respectively, and antioxidant defence system is involved in conferring the sensitiveness and tolerance in these genotypes. Salt-tolerant genotype Pusa-37, was further analysed by 2-dimensional gel electrophoresis to analyse the differential expression of proteins at high salt stress. In the present study, 173 protein spots were identified. Of these, 40 proteins were responsive to salinity in that they were either up- or downregulated. This study could help us in identifying the possible regulatory switches (gene/s) controlling novel proteins of the salt-tolerant genotype of the crop plants and their possible role in defence mechanism.     

Copolyesteramides: synthesis and kinetic analysis

The synthesis of copolyesteramides using para-acetamido benzoic acid (PABA) and polyethylene terephthalate (PET) by melt polymerization has been studied in detail. The performance of three transesterification catalysts are assessed for three different initial compositions, PABA 60 mol%/PET 40%, PABA 50 mol%/PET 50% and PABA 40 mol%/PET 60%. The polycondensations are found to obey second order kinetics, irrespective of whether the reaction was catalysed or not. The mechanism of initial stage polymerization kinetics of the copolymers has been fully explained.It is suggested that acetic acid is evolved only by the homopolymerization of PABA and that the insertion of a monomer of homopolymer of PABA into PET does not yield any acetic acid. A set of differential equations containing three different rate constants, k₁ for homopolymerization of PABA, k₂ for PET reaction with dimer of PABA and k₃ for PABA reaction with copolymer of PABA and PET has been developed and numerically solved, to study the initial stage kinetics. The computed values of acetic acid are compared with the experimentally collected amount and the three rate constants are optimized using a differential algebraic optimization technique. The present model represents the data with an acceptable accuracy with an average % error of less than 5% between experimental and computed values for the entire experimental range. The correlation coefficient values range between 0.988 and 0.999.Differential scanning analysis of the copolyestermides indicates that 40 mol% PABA and 60% PET had the highest enthalpy values of the order of 18 kJ/mol. It is found that within the copolyesteramide series the degree of crystallinity increased with the increase of PET contents in the feed mixture to the batch reactor.     

Metal organic chemical vapour deposition (MOCVD) of bone mineral like carbonated hydroxyapatite coatings

For the first time, the MOCVD technique has been used to deposit carbonated hydroxyapatite onto Ti6AL4V substrates using volatile monomeric (liquid) complexes [Ca(beta-diketonate)(2)(L)] and P(OEt)(3).