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

El género afecta las propiedades contráctiles del músculo sóleo en diabetes inducida experimentalmente en ratas

Ratas hembras y machos, de tres meses de edad, fueron separados en dos grupos: no diabéticas (ND, peso corporal, 274 ± 9 g; nivel de glucosa en la sangre, 4,94 ± 0,22 mmol/L; n = 16) y diabéticas (D; peso corporal, 207 ± 8 g; nivel de glucosa en sangre, 28,39 ± 0,94 mmol/L; n = 16). La diabetes fue inducida por una sola dosis de 60 mg/Kg de estreptozotocina administrada intraperitonealmente. Las ratas ND recibieron el mismo volumen de vehículo. Después de 4 semanas los animales fueron considerados diabéticos si su nivel de glucosa era ≥ 20 mmol/L. La masa y la contracción del músculo sóleo fueron mayores en machos ND que en las hembras ND. En las ratas macho D disminuyó su masa muscular en un 34% y la fuerza de contracción disminuyó en un 33%; mientras que en las hembras D disminuyeron 15% y 10% respectivamente

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

ZnO Nanoparticles Induce Dyslipidemia and Atherosclerotic Lesions Leading to Changes in Vascular Contractility and Cannabinoid Receptors Expression as Well as Increased Blood Pressure

ZnO nanoparticles (ZnONPs) have been shown to have therapeutic potential in some diseases such as diabetes and cancer. However, concentration-dependent adverse effects have also been reported. Studies which evaluate the effects of ZnONPs on the cardiovascular system are scarce. This study aimed to evaluate the cardiovascular effects of a low dose of ZnONPs administered chronically in healthy rats. Changes in dyslipidemia biomarkers, blood pressure, aortic wall structure, vascular contractility, and expression of cannabinoid receptors in the aorta wall were evaluated. Healthy rats were divided into two groups: control or treated (one, two, and three months). The treated rats received an oral dose of 10 mg/kg/day. The results showed that treatment with ZnONPs induced dyslipidemia from the first month, increasing atherosclerosis risk, which was confirmed by presence of atherosclerotic alterations revealed by aorta histological analysis. In in vitro assays, ZnONPs modified the aorta contractile activity in response to the activation of cannabinoid receptors (CB1 and CB2). The expression of CB1 and CB2 was modified as well. Moreover, ZnONPs elicited an increase in blood pressure. In conclusion, long-time oral administration of ZnONPs induce dyslipidemia and atherosclerosis eliciting alterations in aorta contractility, CB1 and CB2 receptors expression, and an increase in blood pressure in healthy rats