Identification of novel inhibitory candidates against two major Flavivirus pathogens via CADD protocols: in silico analysis of phytochemical binding,reactivity, and pharmacokinetics against NS5 from ZIKV and DENV

Structural Chemistry - Zika and dengue virus are flaviviruses which with the passage of time have become a serious challenge affecting millions of people around the world. To lessen the impact of...     

Multifunctional micro-/nanoscaled structures based on polyaniline: an overview of modern emerging devices

With the advent of Materials Science-based technological advances, the fabrication of materials that could simultaneously exhibit both mechanical and processing properties of polymers and unique electrical characteristics of metals is a requirement with prior mandate. With the development of conducting polymers, great opportunities have been established, and novel devices with the significant features have emerged. Polyaniline (PANI) and its derivatives have attracted immense attention because of their fascinating properties, including high conductivity, inexpensiveness of starting material, unique redox behavior, facile synthesis, tunable properties, appropriate electrochemical and environmental stability, and strong bimolecular interactions. Nanostructures based on PANI have shown improved functionalities in various applications. In this article, different synthesis strategies such as interfacial polymerization, microwave-assisted polymerization, and sonochemical polymerization among others have been summarized. Besides, PANI-based nanocomposites and their various industrial, as well as biomedical applications in supercapacitors, batteries, gas vapor sensors, printable electronics, electrochromics, actuators, electrostatic dissipation, electromagnetic interference shielding, corrosion protection, filtration membranes, microbial fuel cell, biosensors, tissue engineering, and drug delivery systems, have been discussed in detail.     

Experimental design as an optimization approach for fabrication a new selective sensor for thallium(I) based on calix[6]arene

The performance of a new membrane sensor based on polyvinyl chloride (PVC) for Tl(I) assay was investigated using the statistical design as an optimization strategy. The Plackett-Burman and Box-Behnken designs, respectively, were utilized to find out the influencing variables and optimization of conditions. In order to evaluate the relationship between the responses of electrode (slope) and significant variables along with their interactions, a mathematical model was presented. The interactions between significant variables were intuitively illustrated according to the response surface plots. Apart from that, the optimum conditions as a result of response surface methodology for both membrane ingredients and measuring conditions such as pH, PVC, internal solution concentration, calix[6]arene, 2-nitrophenyloctylether, potassium tetrakis-(p-chlorophenyl)borate and time conditioning, respectively, were found to be: 6, 0.028 g, 0.001 M, 0.0035 g, 0.065 g, 0.0015 g and 20 h. The optimized sensor exhibits a Nernstian response for thallium(I) over a wide linear range from 2.0 × 10^?6 to 2.0 × 10^?2 M and the slope of 57.9 ± 0.1 mV/decade of the activity and limit of detection (LOD) 1.9 × 10^?5 M. The relative standard deviations (RSD) for six replicates of the measurement at 1 × 10^?5 and 1 × 10^?5 M of Tl(I) were 2.7 and 3.0%, respectively. The favorable results were given through the direct determination of Tl(I) in spiked wastewater and artificial spiked urine sample with Tl(I). The electrode was also successfully applied to the titration of a Tl(I) solution with KI.     

A dicationic,podand-like,ionic liquid water system accelerated copper-catalyzed azide-alkyne click reaction

In this work,an effective,task specific,dicationic,podand-like ionic liquid was synthesized and applied to improve the capability features of click reaction.Moreover,to broaden the scope and decreasing the serious limitations of preparation methods of organic azides,a simple green procedure for the preparation of alkyl azides,the fundamental starting materials in click reactions,from alcohols under solvent-free conditions and microwave irradiation has been reported,for the first time.     

High-performance supercapacitors based on an ionic liquid-derived nanofibrillated mesoporous carbon

This article reports the superior specific capacitance, energy, and power density of a nanofibrillated mesoporous carbon derived from an ionic liquid source (IFMC). It was concluded that high specific capacitance and good electrical conductivity were originated from contribution of nitrogen content of IFMC, also the interesting nanofibrillated structure. A specific capacitance of 235 F g^?1 at a high discharge current of 5 A g^?1 was estimated for IFMC-based electrode which is higher than the most reported capacitance for carbon materials. An excellent performance of the nanofibrillated mesoporous carbon along with proper concentration of nitrogen constituent in the carbonaceous framework is indicative for important effects of tuning the carbon nanostructure for energy storage applications.     

Basic Al2O3 as an Efficient Heterogeneous Reagent for the Synthesis of Symmerical Dialkyl Trithiocarbonates

This work deals with reaction of alkyl halides with carbon disulfide in the presence of basic alumina as heterogeneous and reusable reagent. It afforded symmetrical dialkyl trithiocarbonate in moderate to excellent isolated yields. Reaction of 1,2‐dichloro ethane with carbon disulfide also proceeded in a similar manner to give a five‐membered cyclic trithiocarbonate without formation of any polymeric by‐product.     

Solvent-Free Crossed Aldol Condensation of Cyclic Ketones with Aromatic Aldehydes Assisted by Microwave Irradiation

Summary. A fast alumina-promoted crossed aldol-condensation reaction of aldehydes and cyclic ketones under microwave irradiation is described. This process is simple, efficient, and environmentally benign and proceeds in fairly high yield without any self-condensation.     

Constructing Robust Entangled Coherent GHZ and W States via a Cavity QED System

Using a system of three distant cavities, we propose a method for constructing tripartite entangled coherent GHZ and W states which are robust due to the photon losses in the cavities. Each of cavities is doped with a semiconductor quantum dot. By the dynamics, the excitonic modes of quantum dots are enabled to exhibit entangled coherent GHZ and W states. Apart from the exciton losses, the master equation approach shows that when the populations of the field modes in the cavities are negligible the destruction of entanglement due to dissipation arises from photon losses, is effectively suppressed.     

Discussion on complexation reactions between dicyclohexyl-18-crown-6 (DCH18C6) with Na+, K+, Cs+, Rb+, and Tl+ metal cations in acetonitrile-water binary mixtures

The complex formation between Na⁺, K⁺, Cs⁺, Rb⁺ and Tl⁺ metal cations with macrocyclic ligand, dicyclohexyl-18-crown-6 (DCH18C6) was studied in acetonitrile-water (AN-H₂O) binary systems at different temperatures using conductometric method. DCH18C6 forms 1:1 complexes with these metal cations. The stability constants of the complexes were obtained from fitting of molar conductivity curves using a computer program Genplot. The results show that the selectivity order of DCH18C6 for the metal cations in acetonitrile-water mixtures (AN = 25.3 and 50.4 mol %) is: Tl⁺ > K⁺ > Rb⁺ > Cs⁺ > Na⁺. A non-linear behaviour was observed between the log K _f of the complexes versus the composition of the mixed solvent which it related to changes of acidity, basicity, polarity and also polarizability of AN-H₂O mixtures with the composition of this binary solution. The values of standard enthalpy changes (ΔH _s⁰) for complexation reactions were obtained from the slope of the van’t Hoff plots and the changes in the standard entropy (ΔS _s⁰) were calculated from the relationship: ΔG _s,298.15⁰ = ΔH _s⁰ − 298.15ΔS _s⁰. The obtained results show that in most cases, the complexes are enthalpy stabilized but entropy destabilized. Original Russian Text ? M.H. Soorgi, G.H. Rounaghi, M.S. Kazemi, 2008, published in Zhurnal Obshchei Khimii, 2008, vol. 78, No. 10, pp. 1627–1632.     

Direct synthesis of nitrogen-doped graphene on platinum wire as a new fiber coating method for the solid-phase microextraction of BXes in water samples: Comparison of headspace and cold-fiber headspace modes

In this work, a new solid-phase microextraction fiber was prepared based on nitrogen-doped graphene (N-doped G). Moreover, a new strategy was proposed to solve problems dealt in direct coating of N-doped G. For this purpose, first, Graphene oxide (GO) was coated on Pt wire by electrophoretic deposition method. Then, chemical reduction of coated GO to N-doped G was accomplished by hydrazine and NH₃. The prepared fiber showed good mechanical and thermal stabilities. The obtained fiber was used in two different modes (conventional headspace solid-phase microextraction and cold-fiber headspace solid-phase microextraction (CF-HS-SPME)). Both modes were optimized and applied for the extraction of benzene and xylenes from different aqueous samples. All effective parameters including extraction time, salt content, stirring rate, and desorption time were optimized. The optimized CF-HS-SPME combined with GC-FID showed good limit of detections (LODs) (0.3–2.3 μg/L), limit of quantifications (LOQs) (1.0–7.0 μg/L) and linear ranges (1.0–5000 μg/L). The developed method was applied for the analysis of benzene and xylenes in rainwater and some wastewater samples.