Structural and Electronic Properties of Theophylline- InP Diamantane Drug Carrier

Modeling   and simulation of nanostructure parameters of Theophylline bound with indium phosphide in diamantane structure have been performed with Gaussian 09 program. Density functional theory with hybrid B3LYP/3-21 basis sets was used to investigate the electronic and structural properties for Theophylline bound with InP diamantane nanocrystal as drug carrier. The optimized structures, total energies, energy gaps, highest occupied molecular orbital (HOMO), lowest unoccupied molecular  orbital (LUMO) energy, ionization potentials, electron affinities, chemical potential, global hardness, softness, and electrophilicity index have been investigated. Molecule has the smallest energy gap and the largest value of electrophilicity index in which this indicates that this molecule is more reactive than the others and has large chance to interact with the surrounding species in comparison with the other original Theophylline drug structure. A measure of molecular electrophilicity depends on both the chemical potential and the chemical hardness. The study suggests that the electrophilicity equalization principle is most likely to be a valid theoretical proposition, similar in nature to the electronegativity and hardness equalization principle. Indium Phosphide diamantane nanocrystal and its uses in drug-delivery are also discussed

Tribological Characteristics of Silicon Carbide – Epoxy Nanocomposites

The applications of polymer nanocomposites have been increased in fast, in technological applications and engineering materials for seal and sliding components in many machines, devices, tools and variance vehicles. In this research friction and wear coefficients of epoxy reinforced by nanoparticles silicon carbide in terms of variance volume fractions have been tested. Mechanical – layup method with ultrasonic technique for the dispersion of the nanoparticles within the polymer matrix are used. Wear and friction coefficient tests are created out using pin -on-disc technique. The results showed significant improvement in wear resistance and low coefficient of friction for 10 vol. % nanocomposites compared with the matrix alone. It can be concluded from scanning electron microscopy (SEM) results before and after the tests that the wear was transformed from the severe to the moderate

Electronic, Structural and Vibrational Properties of GaP Diamondoids and Nanocrystals: A Density Functional Theory Study

The electronic, structural and vibrational properties of gallium phosphide diamondoids and nanocrystals were investigated using density functional theory at PBE/6-31(d) level, which included polarization functions. The energy gap obeyed the quantum confinement size effect with shape fluctuations. The gap converged towards its bulk limit at 2.26 eV. The Ga-P bond lengths of higher diamond‐ oids were found to be distributed around the bulk experi‐ mental value at 2.36 Angstrom. Tetrahedral angles were found around the ideal bulk zincblende value at 109.47, degrees while dihedral angles were distributed around the ideal bulk zincblende values at ±60 and ±180 degree. These findings illustrate that diamondoids are a good represen‐ tative of bulk structure. An analysis of vibrational modes, in terms of reduced masses, force constants and IR intensi‐ ty, was then performed. The size-related change of certain vibrational frequencies of GaP diamondoids was compared with the experimental bulk. Radial breathing mode frequency began from 187 cm-1 for the smallest molecule GaPH6 and decreased with fluctuations, heading to 0 cm-1 as its bulk limit. Longitudinal optical mode began from 187 cm-1 for the smallest molecule and increased with fluctua‐ tions, heading to 376.9 cm-1 (11.3 THz) as its bulk limit. Hydrogen-related vibrations were relatively constant and can therefore be used to identify GaP diamondoids because of their high IR and Raman intensity peaks