Cyclopentanone thiosemicarbazone, a new complexing agent for copper determination in biological samples by adsorptive stripping voltammetry.

A selective and sensitive stripping voltammetric method for the determination of trace amounts of copper(II) with cyclopentanone thiosemicarbazone (CPTSC) is presented. The method is based on the adsorptive accumulation of the resulting copper-CPTSC complex on a hanging mercury drop electrode, followed by the stripping voltammetric measurements at the reduction current of the adsorbed complex at -0.37 V vs. Ag/AgCl. The optimal conditions for the stripping analysis of copper include pH 9.3, deposition time of 120 s, and a deposition potential of -0.1 V (vs. Ag/AgCl). The peak current is linearly proportional to the copper concentration over a range 3.14 x 10(-9) M to 1.57 x 10(-6) M with a limit of detection of 1.57 x 10(-9) M. The technique has been applied to the determination of copper in biological samples, like urine and whole blood.     

Ferromagnetic properties of glucose coated Cu2O nanoparticles

Magnetic properties of glucose coated cuprous oxide nanoparticles of different sizes have been studied. Unlike bulk Cu₂O, which shows diamagnetic behavior, the nanoparticles show superparamagnetic behavior. A superparamagnetic blocking temperature of 21 K is observed for 5 nm particles. A magnetic hysteresis loop with a coercivity of 406 Oe is observed for these particles at 5 K. The magnetization and the coercivity increase with decreasing particle size. The superparamagnetic behavior, along with the increase in magnetization and coercivity with decreasing particle size, is due to the enhanced surface contributions to the magnetism.     

Metalation of Biginelli compounds. A general unprecedented route to C-6 functionalized 4-aryl-3,4-dihydropyrimidinones

4-Aryl-6-methyl-3,4-dihydro-2(1H)-pyrimidinone esters (DHPMs) readily undergo metalation at the C-6 methyl (vinylogous ester) position on treatment with lithium diisopropylamide at -10 degrees C. The resulting anion intermediates can be treated with electrophilic reagents to afford functionalized DHPMs that have been chemically elaborated mainly at the C-6 position. Di- and trianion formation is also possible at both the vinylogous methyl and NH positions when reactions are performed with excess equivalents of the base.     

Fabrication and Characterization of Dye-doped Polymeric Mode Filter

Bromocresol Purple (BCP) dye doped SAN films were fabricated by varying the concentration of dye and studied the effect on the optical parameters. The transmission of BCP was above 85% in the range of 550–900 nm. At 0.03% of dye the films showed minimum propagation losses (0.7 db/cm). A mode filter was fabricated using BCP doped SAN films and Methyl Red doped polystyrene films were coated over them. The concentration of Methyl Red in polystrene and BCP in styrene acrylonitrile was varied from 0.01 to 0.05% (w/v). It was observed that at 0.03% of Methyl red and BCP the propagation losses (0.57 db/cm) were minimum in the multilayer structure. BCP doped polymer films can be used to fabricate other photonic devices too.     

Collapse dynamics of liquid bridges investigated by time-varying magnetic levitation

Using a novel technique that facilitates temporal control over the total body force on a liquid, an unexpected scaling relationship was discovered for the collapse time of a liquid bridge. A paramagnetic liquid was suspended between the tips of two collinear rods in a strong magnetic field gradient that was adjusted to compensate gravity. A sudden change of the magnet current, corresponding to a change of Bond number, resulted in a deformation and ultimate collapse of the liquid bridge. The collapse time was found to be independent of the bridge length when other parameters were held constant.     

Resonance Raman and electronic absorption study of free‐base tetraphenylporphine diacid dispersed in polymethylcyanoacrylate

We report a resonance Raman study on free‐base tetraphenylporphine (H₂TPP) and its chemically prepared diacid dispersed in polymethylcyanoacrylate (PMCA). Photoexcitation of the neutral porphine by laser light leads irreversibly to the formation of the diacid, with the π‐cation radical as intermediate species. Resonance Raman (RR) spectra of the diacid dispersed in the polymer obtained with 441.6 nm in the wavenumber region of 100–1650 cm⁻¹ are recorded. Wavenumbers with other excitation lines are also reported for the diacid species. Some bands assigned to out‐of‐plane vibrational modes and forbidden under ideal D_2h symmetry are also observed in the resonance Raman spectra of the diacid. These bands arise from the out‐of‐plane distortions, which reduce the symmetry of the molecule. These findings are supported by the electronic absorption studies of the diacid in the polymer. Copyright © 2007 John Wiley & Sons, Ltd.     

Lie-optic matrix algorithm for computer simulation of paraxial self-focusing in a plasma

Propagation algorithm for computer simulation of stationary paraxial self-focusing laser beam in a medium with saturating nonlinearity is given in Lie-optic form. Accordingly, a very natural piece-wise continuous Lie transformation that reduces to a restricted Lorentz group of the beam results. It gives rise to a matrix method for self-focusing beam propagation that is constructed and implemented. Although the results use plasma nonlinearities of saturable type, and a gaussian initial beam, these results are applicable for other media like linear optical fibers and to more general situations.     

Thermodynamic Properties of Binary Liquid Mixtures of n-Dodecane with an Alkan-1-ol or an Alkan-2-ol at 298.15 K: A Comparative Study

Experimental densities (ρ), viscosities (η), and speeds of sound (u) of the binary mixtures of n-dodecane with an alkan-1-ol (hexan-1-ol, heptan-1-ol, octan-1-ol) or an alkan-2-ol (hexan-2-ol, heptan-2-ol and octan-2-ol) were measured over the whole mixture composition range at T = 298.15 K. From these data, the excess molar volume ( $ V_{\text{m}}^{\text{E}} $ V m E ), deviations in viscosity (Δη), and excess isentropic compressibility ( $ \kappa_{S}^{\text{E}} $ κ S E ) have been calculated. The results were fitted by means of the Redlich–Kister equation, in order to estimate the binary coefficients and standard errors. Differences among these binary systems are ascribed to the different association abilities of the alkan-1-ols and alkan-2-ols. Experimental data on the constituted binaries were analyzed using McAllister’s multi-body interaction model, the Jouyban–Acree model, the Prigogine–Flory–Patterson theory, and the Bloomfield and Dewan model. The experimental and calculated quantities are used to study the nature of mixing behavior among the mixtures.     

High Frequency Shoots Regeneration for Mass Multiplication of Phyllanthus fraternus Webster—An Important Antiviral and Hepatoprotective Plant

An efficient, rapid, and highly reproducible regeneration protocol was successfully developed for Phyllanthus fraternus from the field-derived mature nodal segments. The explants induced multiple shoots on cytokinin containing medium. The highest frequency (99 %) and maximum number of shoots (19.75) were induced on Murashige and Skoog’s (MS) medium supplemented with 2.22 μM 6-benzylaminopurine after 3–4 weeks of culture initiation. The elongated shoots were rooted on MS medium supplemented with indol-3-butyric acid (IBA) or α-naphthalene acetic acid. Pulse treatment of microshoots promoted significant increase in the percentage of rooting and number of root regeneration per shoot. The highest rooting (100 %) and maximum number of roots (8.75) per shoot was obtained when shoots were dipped in IBA solution (0.98 mM) for 5 min and further subcultured on MS basal medium. Plantlets were successfully acclimatized and established in soil. Regenerated plants were grown normally in the field without showing any morphological variations. This cost-effective protocol will help the mass multiplication of P. fraternus for commercial propagation and high biomass production of this valuable medicinal plant.