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Porous structured Au colloids have been prepared from bulk nanoporous Au by means of an element dissociation method. The microscopic techniques (scanning electron microscope and atomic force microscope), UV-Vis spectroscopy and zone diffusion method have been employed to study their morphology, optical property and anti-microbial activity against Gram-positive and Gram-negative bacterial strains, respectively. It is shown that the porous structured Au colloidal suspension exhibit excellent optical and antimicrobial properties. The noticeable features present in the optical studies are two Plasmon resonance peaks at 477 and 546 nm with overlapping of these peaks at a wavelength of 520 nm. The morphology studies by SEM and AFM indicate that the Au colloids are rod shaped with an assembly of skeletal pore and ligament structure. The analysis of the antimicrobial activity testing reveals that the porous structured Au colloids have greater inhibitory effect against the tested Gram-positive and Gram-negative bacterial strains.

We study the efficiency of synchronization in ensembles of identical coupled stochastic oscillator systems. By deriving a chemical Langevin equation, we measure the rate at which the systems synchronize. The rate at which the difference in the Hilbert phases of the systems evolve provides a suitable order parameter, and a 2--dimensional recurrence plot further facilitates the analysis of stochastic synchrony. We find that a global mean--field coupling effects the most rapid approach to global synchrony, and that when the number of "information carrying" molecular species increases, the rate of synchrony increases. The Langevin analysis is complemented by numerical simulations.