In the present study Response surface methodology (RSM) was used to investigate the combined effect of relevant process variables to maximize the production of xylanase in submerge fermentation by Penicillium citrinum MTCC 2553. The process variables include pH (6.5, 7.0, and 7.5); temperature (25, 30, and 35°C); agitation speed (190, 200, and 210 rpm); and, substrate (xylan) concentration (0.7...

Since its formal inception in 1964-1965, Kohn-Sham density-functional theory (KS-DFT) has become the most popular electronic structure method in computational physics and chemistry. Its popularity stems from its beautifully simple conceptual framework and computational elegance. The rise of KS-DFT in chemical physics began in earnest in the mid 1980s, when crucial developments in its exchange-c...

Intertidal mudflats are highly productive ecosystems that impose severe environmental challenges on their occupants due to tidal oscillations and extreme shifts in habitat conditions. Reproduction on mudflats requires protection of developing eggs from thermal and salinity extremes, O(2) shortage, dislodgement by currents, siltation and predation. Mudskippers are air-breathing, amphibious fishe...

We investigate the segregation of a dense binary mixture of granular particles that only differ in their restitution coefficient. The mixture is vertically vibrated in the presence of gravity. We find a partial segregation of the species, where most dissipative particles submerge in the less dissipative ones. The segregation occurs even if one type of the particles is elastic. In order to have ...

In Greek mythology, the river Styx is a river that formed the boundary between earth and the underworld or Hades, the abode of the dead. The ferryman of the river Styx was called Charon, a personification of the decision-making process between life and death. According to some versions of the myth, the river Styx had miraculous powers and could make someone immortal. Achilles was said to have b...