Thermal Characteristics of Gel Grown Lanthanum Heptamolybdate crystals

Thermal characteristics of Ianthanum heptamolybdate crystals grown by gel technique, employing thermoanalytical techniques, viz. TG, DTA and DSC, are reported. It is established that the rare-earth lanthanum heptamolybdate crystals are associated with thirty water molecules;the composition being La2Mo7O24.3OH2O. It is shown that all the thirty water molecules associated with lanthanum heptamolybdate crystal are lost during its decomposition, leading to its anhydrous form. Results obtained on application of TG based models, viz. Horowitz-Metzger,Coats-Redfern and Piloyan-Novikova and of DSC based methods viz. Roger-Morris-Smith and Barret, regarding solid state reaction kinetics are also reported. The random nucleation model is shown to be the one that is relevant to the decomposition of lanthanum heptamolybdate. The kinetic parameters, viz.the order of reaction. frquency factor, energy of activation and entropy using above mentioned models are computed and shown to bear reasonably good agreement     

1,2-Propanediol-induced changes in plasma and tissue lipids of rats

Oral administration of 1,2-propanediol to rats in a daily dose of 1 ml of 28.4% aqueous solution per 100 g body weight for 30 days caused a significant decrease in the total lipids, fatty acids, phospholipids, and triglycerides of plasma, liver, and heart, The cholesterol content in plasma decreased while that in the tissues increased significantly. The accumulation of cholesterol in tissues tends to discourage long term use of 1,2-propanediol even by the oral route.     

Interactive manipulation of three dimensional binary scenes

A general framework for the interactive display and manipulation of the three-dimensional binary scenes is discussed. The procedures for obtaining the shaded graphics display, specification of a secondary object to be used in the manipulative operations of union, subtraction and intersection are described. The methods are illustrated using real medical data as well as regular geometric objects.     

Dynamics of controlled release of potassium nitrate from a highly swelling binary polymeric blend of alginate and carboxymethyl cellulose

Highly water absorbing and homogeneous binary biopolymeric blends in bead form were prepared of calcium alginate and carboxymethyl cellulose by solution cast method. The prepared blends were evaluated for controlled delivery of KNO₃ taking it as a model agrochemical. The beads characterized by Fourier transform infrared spectroscopy (FTIR) and Scanning electron microscopy (SEM) were used to investigate the molecular structure and morphology of beads. The swelling experiments were performed for different compositions of beads and at varying pH and temperature of the aqueous media. The release experiments were performed under static and varying experimental conditions and the release data obtained were conductometrically fitted to Ficks equation to evaluate diffusion coefficients of released KNO₃. The release results were further analyzed by Ficks power law equation, and the possible mechanisms of KNO₃ release were explored at different experimental conditions. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Characterization of gel-grown neodymium heptamolybdate crystals

Neodymium heptamolybdate crystals grown from silica gels [1] are characterized em ploying energy dispersine X-ray analysis, X-ray and electron diffraction, infra-red spectroscopy, optical microscopy and scanning electron microscopy techniques and the results obtained are presented. The crystals are established to have the composition Nd₂Mo₇O₂₄27H₂O. The results of electron diffraction studies indicate the material to be thermally unstable. The crystals growing within the gel medium exhibit varied morphologies including square and octagonal platelets, cuboids, multifaceted crystals, coalesced and aggregated forms and spherulites. The spherulitic morphology is shown to arise due to crystallites adhering in a spherical envelope and are not as a result of crystal fibres radiating out from a centrally located common nucleus. The morphology of the building blocks of the crust at the gel reactant interface is discussed.     

Ion Exchange Properties of Pyridinium Molybdoarsenate

The ion exchange behaviour of pyridinium molybdoarsenate has been investigated with some uni- and bi-valent cations. The slopes of the isotherms are widely different for various cations suggesting that separation of these ions is feasible. Barrer's equation has been applied to the exchange reaction and various thermodynamic parameters, viz. interaction energy between the ions on surface, thermodynamic equilibrium constant and free energy change for the exchange process, have been evaluated. This exchanger is found to be highly specific for Tl⁺ ions and can be used for its removal from mixtures of various uni- and bi-valent cations.     

Low temperature synthesis of hydroxyapatite nano-rods by a modified sol–gel technique

Hydroxyapatite (HAp) nano-rods were successfully synthesized by a modified sol–gel method using a solution of CaCl₂·2H₂O in water, along with a solution of H₃PO₄ in triethylamine and NH₄OH as starting materials. The Ca/P molar ratio was maintained at 1.67. The sol obtained was dried in an oven for 2 days at 100 °C after being dialyzed for 12 h. Pellets were made from the crystalline powders and immersed in simulated body fluid (SBF) to check its biocompatibility after 15, 45 and 180 days of immersion. The HAp powders and pellets were characterized by X-Ray Diffraction crystallography (XRD), Fourier transform Infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and Transmission electron microscopy (TEM). The HAp nano-rods had an average diameter of 25 nm and length 110–120 nm. Immersion of the HAp pellets in SBF led to the formation of a highly porous interconnecting HAp layer on the surface. The porosity increased with increase in immersion time.     

Design,Synthesis, Drug-Likeness and In Silico Prediction of Polycyclic Aromatic Schiff base Tethered Organosilatranes

Silicon - The present article includes the generation of aromatic Schiff base tethered organosilatranes via two step synthetic pathways starting from anthracene-10-carbaldehyde and...