Phase transitions of AlFeO3 and GaFeO3 from the chiral orthorhombic (Pna2(1)) structure to the rhombohedral (R3c) structure.

AlFeO(3) and GaFeO(3), which crystallize in a chiral orthorhombic (Pna2(1)) structure, transform to a rhombohedral (R3c) structure when subjected to ball-milling. There is a distinct difference between the transformations of AlFeO(3) and GaFeO(3). AlFeO(3) first transforms to an orthorhombic P2(1)2(1)2(1) structure followed by its transformation to the R3c structure, while GaFeO(3) goes directly to the R3c structure. The transformations have been characterized by X-ray diffraction and Raman spectroscopy. Magnetic properties of Pna2(1) and the transformed phases show significant differences. It is noteworthy that partial substitution of aluminum by gallium in AlFeO(3) as in Al(0.5)Ga(0.5)FeO(3) eliminates the intermediate P2(1)2(1)2(1) phase, causing direct transformation of the Pna2(1) structure to the R3c structure. All of the transformations are thermodynamically first-order associated with significant changes in volume. We have used first-principles simulations to determine the pressure-dependent properties of AlFeO(3) and GaFeO(3) in orthorhombic and corundum structures and have estimated the critical pressures for the structural phase transition between the two structures. On the basis of this information, we also comment on the differences in the behavior of AlFeO(3) and GaFeO(3) under ball-milling.

Virtual screening of molecular properties of chitosan and derivatives in search for druggable molecules.

Druggability of chitosan monomer and Schiff bases as well as reduced Schiff base derivatives of chitosan were examined. Oral bioavailability and bioactivity of all these molecules against selected drug targets as well as ADME/Tox studies were conducted. All the molecules satisfied Lipinski's rule of five confirming their oral bioavailability. They also show good bioactivity score for protease and enzyme inhibition. ADME/Tox studies conducted shows that almost all the derivatives are free from toxicity risks. It is observed that these molecules exhibit fairly good drug score and are orally viable molecules. Chelation of chitosan and its derivatives with essential metal ions might be the mechanism driving their bioactivity. Thus chitosan monomer and the derivatives studied, can serve as good lead molecules for further research.

One-step synthesis of high-purity fluorous-capped inorganic nanoparticles.

Making use of the fact that perfluorohydrocarbon, and hydrocarbon solvents become miscible at high temperatures, highly pure inorganic nanoparticles capped with fluorous labels have been generated in a one-step synthesis. The procedure involves taking the reactants in a hydrocarbon+perfluorohydrocarbon mixture along with a fluorous reagent and carrying out the reaction at elevated temperatures. On cooling the reaction mixture, fluorous-capped inorganic nanoparticles dispersed in the perfluorohydrocarbon are obtained.