Preparation of Highly Biocompatible ZnSe Quantum Dots Using a New Source of Acetyl Cysteine as Capping Agent

In this paper, we describe a facile method for preparation of ZnSe quantum dots (QDs) using an inexpensive and biocompatible source of acetyl cysteine in aqueous media. The structural properties of the ZnSe QDs have been characterized using XRD, FT-IR, and TEM techniques. The optical properties of the as-prepared QDs were found to be size-dependent, due to the strong confinement regime at relatively low refluxing time. Effect of solution pH and refluxing temperature on absorption and emission characteristics of the ZnSe QDs was studied. The empirical effective mass approximation also reveals that, both solution pH and refluxing temperature parameters would effect on ZnSe QDs growth, and increase their size. However, the influence of the solution pH was found to be more prominent. Water-solubility, high emission intensity and sub-10 nm nanocrystals size are the most essential features that suggest our synthesized aqueous-based ZnSe QDs (with a very cost-effective and biocompatible capping agent) can be utilized for biological intentions.     

Salicylic Acid Stimulates Defense Systems in Allium hirtifolium Grown under Water Deficit Stress

Nowadays, the use of the growth regulator salicylic acid for improving a plant’s resistance to environmental stresses such as drought is increasing. The present study investigated the effect of salicylic acid on the physiological traits, antioxidant enzymes, yield, and quality of Allium hirtifolium (shallots) under drought conditions for three years (2016–2017, 2017–2018, and 2018–2019). The experiment was conducted as a split-plot based on a randomized complete block design with four repeats. Irrigation as the main factor in four levels of 100% (full irrigation), 75% and 50% of the plant water requirements with non-irrigation (dryland), and salicylic acid as the sub-factor in four levels of 0, 0.75, and 1 mmol, were the studied factors in this research. The combined analysis of three-year data showed that drought reduced leaf relative water content (RWC), membrane stability index (MSI), chlorophyll content, onion yield, and increased activity of antioxidant enzymes, proline content, tang, and allicin of shallots. Shallot spraying with salicylic acid improved leaf RWC, MSI, chlorophyll content, and onion yield. The highest yield of onion (1427 gr m⁻²) belonged to full irrigation and foliar application of 1 mmol salicylic acid. The lowest yield (419.8 gr m⁻²) belonged to plats with non-irrigation and non-application of salicylic acid. By improving the effective physiological traits in resistance to water deficit, salicylic acid adjusted the effects of water deficit on the yield of shallots. Foliar application of 1 mmol salicylic acid in dryland and irrigation of 50% of the plant water requirement increased onion yield by 15.12% and 29.39%, respectively, compared to the control treatment without salicylic acid.     

Supersymmetric solutions of <Emphasis Type="Italic">PT</Emphasis>-/non-<Emphasis Type="Italic">PT</Emphasis>-symmetric and non-Hermitian screened Coulomb potential via Hamiltonian hierarchy inspired variational method

The supersymmetric solutions of PT -symmetric and Hermitian/non-Hermitian forms of quantum systems are obtained by solving the Schr?dinger equation for the Exponential-Cosine Screened Coulomb potential. The Hamiltonian hierarchy inspired variational method is used to obtain the approximate energy eigenvalues and corresponding wave functions.      

Facile Biosynthesis of Silver Nanoparticles Using <Emphasis Type="Italic">Descurainia sophia</Emphasis> and Evaluation of Their Antibacterial and Antifungal Properties

The objective of the present study was to evaluate efficiency of silver nanoparticles (Ag-NPs) biosynthesis using Descurainia sophia as a novel biological resource. The resulting synthesized Ag-NPs were characterized using UV visible spectroscopy, X-ray diffraction, transmission electron microscopy and dynamic light scattering (DLS). The UV–Vis spectra gave surface plasmon resonance at ~420 nm. TEM images revealed formation spherical shaped Ag-NPs with size ranged from to 1–35 nm. DLS confirmed uniformity of the synthesized Ag-NPs with an average size of ~30 nm. Following, the antibacterial and antifungal activities of the synthesized Ag-NPs were investigated. The concentration 25 µg/ml of the Ag-NPs showed maximum inhibitory effect on mycelium growth of Rhizoctonia solani (More than 86 % inhibition), followed by 15 µg/ml (55 % inhibition) and 10 µg/ml (63 % inhibition). The minimum inhibitory concentration and minimum bactericidal concentration of Ag-NPs against Agrobacterium tumefaciens (strain GV3850) and A, rhizogenes (strain 15843) were 4 and 8 µg/ml, respectively. The Ag-NPs were stable in vitro for 3 months without any precipitation or decrease of antifungal effects. Finally, it could be concluded that D. sophia can be used as an effective method for biosynthesis of nanoparticles, especially Ag-NPs.     

Optimal economic load dispatch based on wind energy and risk constrains through an intelligent algorithm

This article focus on optimal economic load dispatch based on an intelligent method of shark smell optimization (SSO). In this problem, the risk constrains has been considered which has root in uncertainity and unpredictable behavior of wind power. Regarding to increasing of this clean energy in power systems and un‐dispatchable behavior of wind power, its conditional value at risk index considered in this article which consists of loss from load and "spilling" wind energy connected with unpredictable imbalances among generation and load. This problem has been considered as an optimization problem based on SSO that evaluate the balance between cost and risk. This algorithm is based on distinct shark smell abilities for localizing the prey. In sharks' movement, the concentration of the odor is an important factor to guide the shark to the prey. In other words, the shark moves in the way with higher odor concentration. This characteristic is used in the proposed SSO algorithm to find the solution of an optimization problem. Effectiveness of the proposed method has been applied over 30‐bus power system in comparison with other techniques. © 2016 Wiley Periodicals, Inc. Complexity 21: 494–506, 2016     

Mn(III)-porphyrin/graphene oxide nanocomposite as an efficient catalyst for the aerobic oxidation of hydrocarbons

In this study, manganese porphyrin was grafted on the surface of graphene oxide nanosheets via covalent bonding to produce a heterogeneous catalyst. The prepared nanocomposite was characterized using X-ray diffraction, UV–vis spectroscopy, scanning electron microscopy, Fourier transform infrared, and thermogravimetric analysis. Atomic absorption spectroscopy was also used to determine the amount of the loaded catalyst. The catalytic efficiency of the immobilized Mn-porphyrin was investigated for the aerobic oxidation of alkenes and saturated alkanes in acetone under mild reaction conditions. The prepared heterogenized catalyst displays superior catalytic performance as compared to the homogeneous catalyst. Moreover, the excellent turnover number (more than 31,767) achieved for the oxidation of styrene indicates the high longevity of the supported catalyst. The catalyst structure is preserved well after the oxidation reaction and is simply reused at least five times, without any significant loss of the catalytic efficiency.     

MnO<Subscript>2</Subscript>/3MgO Nanocomposite for Preconcentration and Determination of Trace Copper and Lead in Food and Water by Flame Atomic Absorption Spectrometry

The presented study investigates the application of MnO₂/3MgO nanocomposite, as a new sorbent for solid phase extraction and determination of trace amounts of Pb²⁺ and Cu²⁺ from various samples using flame atomic absorption spectrometry. After extraction, the analytes were desorbed using 0.01 M ethylenediaminetetraacetic acid. The effects of various parameters were studied and optimized. Under optimized experimental conditions the linear dynamic ranges for Cu²⁺ and Pb²⁺ were 10?900 and 30?900 μg/L, respectively, with a preconcentration factor of 20. The detection limits of Cu²⁺ and Pb²⁺ were 4 and 11 μg/L, respectively, and relative standard deviations for eight determinations of 100 μg/L were 3.6 and 3.8% for Cu²⁺ and Pb²⁺, respectively. The method was successfully applied for determination of copper and lead in mushrooms, rice, tap water and refinery wastewater with good spike recoveries ranging between 95?106%.     

Generalized second derivative linear multistep methods for ordinary differential equations

Numerical Algorithms - This paper is devoted to investigate the modified extended second derivative backward differentiation formulae from second derivative general linear methods point of view....     

Silver nanoparticles modified with thiomalic acid as a colorimetric probe for determination of cystamine

Microchimica Acta - The authors describe a colorimetric method for highly selective determination of cystamine using silver nanoparticles capped with thiomalic acid (TMA-AgNPs). The TMA-AgNPs...