Centrifugal distortion constants of the NGLT form of allylamine from microwave spectrum analysis

The centrifugal distortion analysis of the microwave spectrum of the N-gauche lone-electron-pair trans (NGLT) rotameric form of allylamine has been carried out in the frequency region 5–40 GHz and up to J = 29 in its ground vibrational state. The analysis gives effective rotational constants and all the quartic centrifugal distortion constants.     

Raman spectrum of Cs2So4 using Ar+ laser excitation

Raman spectrum of a Cs₂SO₂ single crystal has been recorded and measured using an Ar⁺ laser as a source of excitation. The polarization behaviour of the Raman lines under different crystal orientations has been studied. Symmetry co-ordinates of the Raman active lattice modes as worked out from group theoretical concepts are presented.     

Urey-Bradley force field—ketene and ketene-d 2

Urey-Bradley force constants of ketene and deuteroketene have been evaluated by the normal co-ordinate treatment. Using these force constants, the fundamental vibrational wave-numbers for ketene and its deuterium analogue have been calculated and compared with the observed bands.     

Electron paramagnetic resonance of Mn2+ in NaF single crystals

The electron paramagnetic resonance of Mn²⁺ in NaF single crystals is investigated at different temperatures from 573° K to 93° K. Four different spectra designated as I, II, III₂ and III₄ are observed. Spectrum I consists of a single broad resonance corresponding to precipitated Mn²⁺ ions. Spectrum II is isotropic and centred nearg = 2.00. This spectrum corresponds to substitutional Mn²⁺ ions with remote charge compensating sites and therefore with local cubic symmetry. Spectrum III₂ withg = 2.014 and spectrum III₄ withg = 1.995 are also due to substitutional Mn²⁺ ions but subjected to tetragonal crystalline fields and are the same as those reported by earlier workers. Superhyperfine structure has been observed in spectra II, III₂ and III₄. The analysis of that structure in spectra II and III₂ has been carried out for the first time and the constants A_s, and A_σ are given. The spectra are analysed by the usual spin-Hamiltonian method.     

Intensity studies in Raman effect: Effect of temperature: Part I (Liquids)

The influence of temperature on the intensities of Raman lines in some polar and nonpolar liquids has been investigated and certain conclusions regarding the temperature dependence of the intensities of the Raman lines have been arrived at.     

Asymmetric Total Synthesis of Stagonolide F

A highly convergent stereoselective total synthesis of stagonolide F is described starting from commercially available 5-hexen 1-ol using asymmetric dihydroxylation, Jacobsen^'s hydrolytic kinetic resolution (HKR), regioselective epoxide ring opening with vinyl Grignard reaction, esterification, and ring-closing metathesis (RCM) as key steps.     

Low dose aspirin estimation: an application to a human pharmacokinetic study

Low dose to very high dose aspirin is used to prevent heart attack. We have developed and validated a sensitive and robust method that could detect low levels of aspirin and salicylic acid in plasma and also a novel sample collection procedure to carry out sample preparation at room temperature. The total run time was 3.00 min; the developed method was validated in human plasma with a lower limit of quantitation of 0.99 ng/mL for aspirin and 2.01 ng/mL for salicylic acid. A linear response function was established for the range of concentrations 0.99–756.20 ng/mL (r > 0.998) for aspirin and 2.01–2486.86 ng/mL for salicylic acid. The intra‐ and inter‐day precision values for aspirin and salicylic acid met the acceptance as per FDA guidelines. The developed assay method was applied to an oral pharmacokinetic study in humans. Copyright © 2012 John Wiley & Sons, Ltd.     

Enhanced conductivity and electrical relaxation studies of carbon-coated LiMnPO4 nanorods

Lithium manganese phosphate (LiMnPO₄) nanorods were synthesized using the modified polyol method. Polyvinylpyrrolidone was used as a stabilizer to control the shape and size of LiMnPO₄ nanorods. Resin coating process was used to coat the carbon over the LiMnPO₄ nanorods. X-ray diffraction and Fourier transform infrared spectroscopy results showed the formation of LiMnPO₄ crystalline phase. The TEM image shows a uniform coating of the nano size (2.3 nm) carbon over the surface of LiMnPO₄ nanorods and the EDS spectrum of the carbon-coated LiMnPO₄ nanorods confirming the presence of carbon element along with the other Mn, P, and O elements. Impedance measurements were made on pure and carbon-coated LiMnPO₄ nanorods, and their conductivities were evaluated by analyzing the measured impedance data using the WinFIT software. More than two orders of magnitude of conductivity enhancement was observed in the carbon-coated LiMnPO₄ nanorods compared to pure ones, and the conductivity enhancement may be attributed to the presence of carbon over LiMnPO₄ nanorods. Temperature dependence of conductivity and ac conductivity were calculated using impedance data of pure and carbon-coated LiMnPO₄ nanorods. CR2032 type lithium ion coin cells were fabricated using pure and carbon-coated LiMnPO₄ nanorods and characterized by measuring charge–discharge cycles between 2.9 and 4.5 V at room temperature. More than 25 % of improved capacity was achieved in the carbon-coated LiMnPO₄ nanorods when compared to pure ones synthesized using modified polyol and resin coating processes.