ΛΛ 6 hypernucleus in α + 2Λ cluster model

The binding energy of the double hypernucleus _ΛΛ ⁶ is calculated in α + 2Λ cluster model using the method of translation invariant basis TIMO. As regards the required interaction potentials we use a density dependent effective ΛN force and a gaussian form for ΛΛ potential. With these interactions a very reasonable value ofB _ΛΛ is obtained if the oscillator states up to the excitation quantum numberN=12 are taken into account in the expansion of wavefunction of the hypernucleus. This value ofN is much smaller than that obtained in an earlier study. This lowering inN value is attributed to a much better choice of ΛN potential used in the present study.     

Spectrophotometric determination of tranexamic acid in pharmaceutical bulk and dosage forms.

In this study, a simple, fast, accurate and sensitive spectrophotometric method has been developed for the determination of tranexamic acid in bulk and pharmaceutical preparations. The method is based on the reaction of ninhydrin with the primary amino group of tranexamic acid in the basic medium at pH 8.0. The reaction produces a bluish-purple color which absorbs maximally at 565 nm. Beer's law was obeyed in the range of 3-40 microg ml(-1) with molar absorptivity of 5.093 x 10(3) L mol(-1) cm(-1). The effects of various factors such as temperature, heating time, concentration of reagent, color stability and interferences were investigated to optimize the procedure. The results have been validated analytically and statistically. The proposed method has been applied for the determination of tranexamic acid in bulk and pharmaceutical preparations with good results.     

Selective reduction and functionalization of diethyl 1-alkyl-1H-indole-2,3-dicarboxylates

A convenient and highly selective reduction of easily accessible indole-2,3-dicarboxylates is described. Ten different 1-alkyl-2-formyl-1H-indole-3-carboxylates are obtained in high yield and represent interesting building blocks for novel indoles.     

TmDOTA-: a sensitive probe for MR thermometry in vivo.

The lanthanide complex, thulium 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (TmDOTA-), has been investigated as an agent for MR thermometry in vivo. The chemical shifts of the TmDOTA- protons were highly sensitive to temperature at a clinically relevant field strength, yet insensitive to pH and the presence of Ca2+. Given the excellent stability of lanthanide-DOTA complexes and high thermal sensitivity, TmDOTA- is expected to be a good candidate for MR thermometry in vivo.     

Investigations of the use of 4-(5-nonyl)pyridine as a liquid anion exchanger for tetrachloroferrate ions in aqueous chloride media

In an attempt to gain an understanding of factors affecting the extraction of iron(III) by 4-(5-nonyl)pyridine, the equilibria between hydrogen chloride and benzene solutions of 4-(5-nonyl)pyridine have been studied. From acid distribution data and visible absorption spectra of the organic phases, it was concluded that FeCl ₄ ⁻ ion, with a tetrahedral sp³ configuration is the principal iron containing species. The pyridine extraction of macro and trace amounts of the metal has indicated the formation of 1∶1 and 2∶1 complexes respectively. The 2∶1 complexes are assumed to result from association of a 1∶1 complex with a molecule of the pyridine hydrochloride. The salting-out effect increases in the order, LiCl<NaCl<MgCl₂<AlCl₃ and these differences in the effect have been attributed to the different degree of hydration of cations of the salts present and to the ionic radii. The effect of various anions including the reducing agents have been described. Separation factors of several metal ions relative to ferric iron, in 6M HCl, are also reported.     

Poly (vinyl chloride) decomposition in solution

Thermal degradation of PVC in various solvents at 180° has been observed to be in the following order: benzonitrite > nitrobenzene > cyclohexanone > dioctyl phthalate > α-bromonaphthalane > decahydronaphthalene. The effect has been explained on the basis of β-eliminations of E₁-type favoured by polar solvents. An inhibition in PVC degradation has been observed in nitrobenzene containing stationary hydrogen chloride gas. The deceleration in degradation by predissolved HCl has been accounted for as a Mass Law effect.     

Mixed convection on a vertical circular cylinder

The problem of the mixed convection boundary-layer flow past an isothermal vertical circular cylinder is considered in both the cases when the buoyancy forces aid and oppose the development of the boundary layer. A series solution is obtained, valid near the leading edge, and this is extended by a numerical solution of the full equations, which in the aiding case, becomes inaccurate downstream. An approximate solution is also derived which gives a good estimate for the heat transfer near the leading edge and has the correct asymptotic form well downstream. In the opposing case, the boundary layer is seen to separate at a finite distance downstream, with, for moderate values of the buoyancy parameter, the numerical solution indicating a regular behaviour near separation.     

A new alkylated benzoquinone from rhizomes of Iris kumaonensis

A novel alkylated unsaturated p-benzoquinone designated as 3-[(z)-12'-heptadecenyl]-2-hydroxy-5-methoxy-1,4-benzoquinone was isolated from hexane extract of the rhizomes of Iris kumaonensis and it's structure was confirmed by extensive spectroscopic analysis, IR, MS, HREIMS, 1D, 2D NMR and comparison with the literature data of known compounds.     

A new phthalic acid ester from Ajuga bracteosa

A new phthalic acid ester 1,2-benzenedicarboxylic acid bis(2S-methyl heptyl) ester (1) was isolated from the hexane extract of the whole plant of Ajuga bracteosa. In addition, chloroform and methanol extracts yielded neo-clerodane diterpene ajugarin-I and two iridoid glycosides, reptoside and 8-O-acetyl harpagide. The structures of all the compounds were confirmed by extensive spectroscopic analysis. From the two oily fractions nine and six volatile constituents respectively were identified by GCMS. Linalyl acetate was found to be common in both the oil fractions. This plant is a new source of linalyl acetate, a valuable perfumery compound.