Third order nonlinear optical properties of organometal halide perovskite by means of the Z-scan technique

The nonlinear optical response of CH3NH3PbBr3 perovskites is investigated using Z-scan technique, employing 10 ns laser pulses, at 532 nm. The systems were found to exhibit strong nonlinear optical response, dominated by nonlinear refraction. The effect of organic and inorganic composition ratio on the nonlinear susceptibility is studied experimentally. In all cases, the nonlinear absorption and refraction have been determined. The corresponding third-order susceptibilities and second-order hyperpolarizability are determined to be as large as 10−6 (esu) and 10−28 (esu) under ns laser excitation respectively. Showing large third-order optical nonlinearity in CH3NH3PbBr3 thin films, suggesting their potential for photonics applications

Role of nitric-oxide in cardiac effects of glibenclamide in rat

Background: There are reports of cardiovascular complications in patients with diabetes that are caused by glibenclamide. On the other hand, nitric oxide has been mentioned as an important factor in the physiology and disorders of the heart in recent studies. Objective: The aim of this study was to determine the role of nitric-oxide in cardiac effects of glibenclamide. Methods: This experimental study was conducted in 42 male rats at Tehran University of Medical Sciences in 2011. Rat atria were isolated after anesthesia and were transferred to an organ bath containing oxygenated Krebs’ solution. Atrial contractions were measured using a physiograph. The samples were divided into 7 groups (n=6): Control group in which the atrial contractions were recorded without medication, Tween-80 group, L-arginin group, L-NAME group, Glibenclamide (Glb) group, Glb+L-arginin group in which the atrial contractions were recorded in the presence of glibenclamide and L-Arginin, and Glb+L-NAME group in which the atrial contractions were recorded in the presence of glibenclamide and L-NAME. Data were analyzed using two-way ANOVA. Findings: Glibenclamide increased the amplitude of atrial contractions. L-NAME and L-arginin did not change the effect of glibenclamide. L-arginine decreased the amplitude of atrial contractions and L-NAME increased the amplitude of atrial contractions. Conclusion: The effect of glibenclamide is independent of nitric-oxide. Keywords: Glibenclamide, Nitric-Oxide, Heart Atria, Rat

Controllable spin-dependent transport in silicene superlattice

Based on the transfer-matrix method, we theoretically investigate the spin-dependent transport properties in magnetic silicene superlattice in the presence of extrinsic Rashba spin–orbit interaction (RSOI). It is found that the spin transmission probability and spin conductivities can be efficiently controlled by the number of magnetic barriers. As the number of magnetic barriers increases, spin conductivities strongly decrease, and reduce to zero in the large on-site potential difference between A and B sublattices (Δz) region. The results indicate that a magnetic silicene superlattice exhibits a remarkable wavevector-dependent spin filtering effect. Also, the magnetoresistance (MR) ratio exhibits an oscillatory behavior with the Fermi energy. The MR ratio can be tuned by the Fermi energy, number of magnetic barriers and extrinsic RSOI. Specifically, in the presence of magnetic field the spin polarization can be observed, and increases by increasing the magnetic field

Effects of strain on shot noise properties in graphene superlattices

In this paper the transmission and the shot noise properties through the strain-induced graphene superlattices are studied. It is found that for the zigzag direction strain the Fano factor shows a peak at new Dirac-like point and the position of the new Dirac point varies against the strain. Also, Fano factor has an oscillatory behavior with respect to strain strength and the oscillation period decreases by increasing the number of barriers. However, for the armchair direction strain the transmission can be blocked by the electric barrier and the Fano factor approaches 1, this is different from the zigzag direction strain

Blood antioxidant levels and alterations of serum calcium and pH in hemodialysis patients

Background: The risk of atherosclerosis and cancer is high in hemodialysis (HD) patients. There is evidence that HD causes oxidative stress. However, the causative factors of oxidative stress are unknown. It has been suggested that HD imposes an additional oxidative stress on patients with chronic renal failure by activation of granulocytes on dialyzer membranes resulting in an imbalance between oxidants and antioxidants. In this regard, a number of reports, either measuring specific analytes or enzymes, or estimating the total antioxidant activity of the plasma have given contradictory and inconclusive results. To investigate the oxidative stress status in Iranian HD patients, in this study, we evaluated GSH and FRAP levels along with Ca and pH in the blood of these patients.Methods: Along with 20 healthy age and gender matched control subjects, 24 patients underwent dialysis, three times per week, for four hours in each session. Before and after dialysis, blood was taken for biochemical and liver function tests and to evaluate oxidative stress markers and measure Ca and pH levels.Results: There was a significant decrease in FRAP and GSH levels after dialysis compared to those before treatment. Dialysis caused an increase in pH and Ca levels compared to levels in control subjects after dialysis.Conclusion: In general, before dialysis, there is a balance between oxidants and antioxidants; however, due to higher levels of oxidants as well as the possible binding of antioxidants to the dialyzer membrane during dialysis, an imbalance occurs. The instability in the balance of oxidants and antioxidants may be the major cause of cellular oxidative damage found in HD patients. This study indicates that there is a significant level of oxidative stress in renal chronic patients and this stress is augmented by dialysis. Antioxidant therapy should be considered in these patients

The “Electric Mondrian” as a Luminescent Solar Concentrator Demonstrator Case Study

Inspired by the works of the Dutch artist Piet Mondrian an Electric Mondrian has been developed built up from luminescent solar concentrator elements. It is based on differently colored square and rectangular elements of standard sizes based on multiples of 15 cm, as this the standard size of the c-Si cells that are used at the sides of the elements. This paper describes the design requirements and choices that have been made in detail. The design is based on commercially available luminescent concentrator Perspex plates and solar cells. Performance testing showed that at total size of 1 m2 a light-to-electric power device efficiency is measured of 0.2%: the Electric Mondrian thus provides ∼2 W in full sun, and two mobile devices can be charged directly or via a built-in battery. The Electric Mondrian functions as a decorative energy-harvesting element indoors in the urban environment, and can be marketed as such