An LSB Data Hiding Technique Using Natural Numbers

In this paper, a novel data hiding technique is proposed, as an improvement over the Fibonacci LSB data-hiding technique proposed by Battisti et al,based on decomposition of a number (pixel-value) in sum of natural numbers. This particular representation again generates a different set of (virtual) bit-planes altogether, suitable for embedding purposes. We get more bit-planes than that we get using Prime technique.These bit-planes not only allow one to embed secret message in higher bit-planes but also do it without much distortion, with a much better stego-image quality, and in a reliable and secured manner, guaranteeing efficient retrieval of secret message. A comparative performance study between the classical Least Significant Bit(LSB) method, the Fibonacci LSB data-hiding technique and the proposed schemes indicate that image quality of the stego-image hidden by the technique using the natural decomposition method improves drastically against that using Prime and Fibonacci decomposition technique. Experimental results also illustrate that, the stego-image is visually indistinguishable from the original cover-image. Also we show the optimality of our technique.Comment: 6 Pages, 5 Figures, IEEE Third International Conference on Intelligent Information Hiding and Multimedia Signal Processing, IIHMSP 2007, Nov 26-28, 2007, Kaohsiung City, Taiwan, IEEE Computer Society press, USA, ISBN 0-7695-2994-1, pp. 473-476, 2007

Formulation and evaluation of gliclazide loaded controlled release microspheres

The aim of this study was to formulate gliclazide loaded controlled release microspheres. Microspheres were prepared by quasi emulsion solvent diffusion technique using eudragit RLPO, eudragit RSPO and with their various combinations. The effect of different formulation variables (drug-polymer ratio and polymer-polymer ratio) on percent yield, mean particle size, encapsulation efficiency and in vitro release of drug were evaluated. In vivo test of the optimized formulation was performed on streptozotocin induced type-2 diabetic rat model. The formulated microspheres showed higher encapsulation efficiencies within the range of 72-84 %. Mean particle size, encapsulation efficiency and in vitro release were found to be affected by changing in formulation variables. In vitro release study revealed the gliclazide release from the microspheres was extended for more than 12 h. In vivo hypoglycemic effect of microspheres was more than 25 h suggesting microspheres are a valuable system for sustained delivery of gliclazide.Colegio de Farmacéuticos de la Provincia de Buenos Aire

Formulation and evaluation of gliclazide loaded controlled release microspheres

The aim of this study was to formulate gliclazide loaded controlled release microspheres. Microspheres were prepared by quasi emulsion solvent diffusion technique using eudragit RLPO, eudragit RSPO and with their various combinations. The effect of different formulation variables (drug-polymer ratio and polymer-polymer ratio) on percent yield, mean particle size, encapsulation efficiency and in vitro release of drug were evaluated. In vivo test of the optimized formulation was performed on streptozotocin induced type-2 diabetic rat model. The formulated microspheres showed higher encapsulation efficiencies within the range of 72-84 %. Mean particle size, encapsulation efficiency and in vitro release were found to be affected by changing in formulation variables. In vitro release study revealed the gliclazide release from the microspheres was extended for more than 12 h. In vivo hypoglycemic effect of microspheres was more than 25 h suggesting microspheres are a valuable system for sustained delivery of gliclazide.Colegio de Farmacéuticos de la Provincia de Buenos Aire

Enzyme leaps fuel antichemotaxis

There is mounting evidence that enzyme diffusivity is enhanced when the enzyme is catalytically active. Here, using superresolution microscopy [stimulated emission-depletion fluorescence correlation spectroscopy (STED-FCS)], we show that active enzymes migrate spontaneously in the direction of lower substrate concentration (???antichemotaxis???) by a process analogous to the run-and-tumble foraging strategy of swimming microorganisms and our theory quantifies the mechanism. The two enzymes studied, urease and acetylcholinesterase, display two families of transit times through subdiffraction-sized focus spots, a diffusive mode and a ballistic mode, and the latter transit time is close to the inverse rate of catalytic turnover. This biochemical information-processing algorithm may be useful to design synthetic self-propelled swimmers and nanoparticles relevant to active materials. Executed by molecules lacking the decision-making circuitry of microorganisms, antichemotaxis by this run-and-tumble process offers the biological function to homogenize product concentration, which could be significant in situations when the reactant concentration varies from spot to spot