Two dimensional modulational instability in photorefractive media

We study theoretically and experimentally the modulational instability of broad optical beams in photorefractive nonlinear media. We demonstrate the impact of the anisotropy of the nonlinearity on the growth rate of periodic perturbations. Our findings are confirmed by experimental measurements in a strontium barium niobate photorefractive crystal.Comment: 8 figure

EFFECTS OF THE ANNEALING AND CdCl 2 TREATMENT ON THE STRUCTURAL AND OPTICAL PROPERTIES OF AMMONIA-FREE AND AMMONIA CdS THIN FILMS BY CHEMICAL BATH DEPOSITION

CdS thin films, with and without ammonia, were prepared using the chemical bath deposition method (CBD), with bath temperature of 70 0 C, 20 and 60 min times of reaction and different complexing agents. We study the effects of CdCl 2 treatment and annealing on these films. The thin films were characterized by X-Ray diffraction (XRD), Scanning Electron Microscopy (SEM), optical absorption spectroscopy and Atomic Force Microscopy (AFM). The XRD measurements showed that the films have polycrystalline nature, hexagonal structure and the crystallites are oriented preferentially with the (002) and (110) planes. The optical absorption measurements show the presence of direct transition with energy band gaps of 2.55 eV and 2.44 eV and after diminished to 2.37 eV and 2.36 eV

BIOCOMPATIBLE SILVER NANOPARTICLES SYNTHESIZED USING RUMEX HYMENOSEPALUS EXTRACT DECREASES FASTING GLUCOSE LEVELS IN DIABETIC RATS

The objective of this study was to evaluate the antihyperglycemic activity of silver nanoparticles (SNPs) produced using green chemistry in a model of stretozotocin (STZ)-induced experimental diabetes in rats. Green SNPs (GSNPs) were synthesized using Rumex hymenosepalus extracts as reducing agent. In control and hyperglycemic rats was performed the measurement of blood glucose levels and glucose tolerance tests. Posteriorly, low dose of GSNPs were administrated in diabetic rats and was evaluated fasting blood glucose and glucose tolerance tests, pre and post-treatment. The basal level of fasting blood glucose of all rats (103.5 ± 4.4 mg/dL) increased after diabetes induction with STZ (315.2 ± 36.1 mg/dL). The treatment with GSNPs during 9 days decreased 50% the blood glucose in diabetic rats. The glucose tolerance test showed that in diabetic rats treated with GSNPs induces a minimal increase in blood glucose. In conclusion, a low dose of GSNPs showed antihyperglycemic activity