Bright-dark and dark-dark solitons in coupled nonlinear Schrödinger equation with PT-symmetric potentials.

We explore different nonlinear coherent structures, namely, bright-dark (BD) and dark-dark (DD) solitons in a coupled nonlinear Schrödinger/Gross-Pitaevskii equation with defocusing/repulsive nonlinearity coefficients featuring parity-time ( PT)-symmetric potentials. Especially, for two choices of PT-symmetric potentials, we obtain the exact solutions for BD and DD solitons. We perform the linear stability analysis of the obtained coherent structures. The results of this linear stability analysis are well corroborated by direct numerical simulation incorporating small random noise. It has been found that there exists a parameter regime which can support stable BD and DD solitons.

Spectroscopic and molecular docking studies on the interaction of troxerutin with DNA.

Troxerutin (TXER) is a derivative of naturally occurring bioflavonoid rutin. It possesses different biological activities in rising clinical world. The biological activity possessed by most of the drugs mainly targets on macromolecules. Hence, in the current study we have examined the interaction mechanism of TXER with calf thymus DNA (CT-DNA) by using various spectroscopic methods, isothermal titration calorimetry (ITC) and molecular docking studies. Further, DNA cleavage study was carried out to find the DNA protection activity of TXER. UV-absorption and emission spectroscopy showed low binding constant values via groove binding. Circular dichroism study indicates that TXER does not modify native B-form of DNA, and it retains the native B-conformation. Furthermore, no effective positive potential peak shift was observed in TXER-DNA complex during electrochemical analysis by which it represents an interaction of TXER with DNA through groove binding. Molecular docking study showed thymine guanine based interaction with docking score -7.09 kcal/mol. This result was compared to experimental ITC value. The DNA cleavage study illustrates that TXER does not cause any DNA damage as well as TXER showed DNA protection against hydroxyl radical induced DNA damage. From this study, we conclude that TXER interacts with DNA by fashion of groove binding.

Vector rogue waves and dark-bright boomeronic solitons in autonomous and nonautonomous settings.

In this work we consider the dynamics of vector rogue waves and dark-bright solitons in two-component nonlinear Schrödinger equations with various physically motivated time-dependent nonlinearity coefficients, as well as spatiotemporally dependent potentials. A similarity transformation is utilized to convert the system into the integrable Manakov system and subsequently the vector rogue and dark-bright boomeronlike soliton solutions of the latter are converted back into ones of the original nonautonomous model. Using direct numerical simulations we find that, in most cases, the rogue wave formation is rapidly followed by a modulational instability that leads to the emergence of an expanding soliton train. Scenarios different than this generic phenomenology are also reported.

The extra cellular synthesis of gold and silver nanoparticles and their free radical scavenging and antibacterial properties.

The bio reduction of chloro auric acid (HAuCl(4)) and silver nitrate (AgNO(3)) is achieved extracellularly by using the aqueous extract of Solanum torvum (S. torvum) fruit. The nanoparticle formation was screened by UV-visible spectroscopy through color conversion due to surface plasma resonance bands at 560 nm and 430 nm for gold and silver nanoparticles respectively. The spherical shapes with smooth surface of gold and silver nanoparticles were analyzed through scanning electron microscope and its presence was confirmed by energy dispersive X-ray spectroscopy (SEM/EDX). The functional groups in the gold and silver salts and the bio interactive functional groups present in the S. torvum extract were characterized by employing Fourier transform infra-red spectroscopy (FTIR). The biomedical properties of gold and silver nanoparticles were premeditated as free radical scavenging activity and antibacterial static agents. Gold and silver nanoparticles serve as strong hydroxyl, superoxide, nitric oxide and DPPH radical scavengers in contrast to their corresponding metal oxides. The radical quenching properties of gold and silver nanoparticles were found to correlate with in vitro DNA protective effect. The silver nanoparticles show strong zone of inhibition against Escherichia coli, Pseudomonas and Bacillus whereas, gold nanoparticles exhibit fair zone of inhibition. To our knowledge this is the first report that S. torvum extract can reduce metal acids to nano materials.

Evaluation of antioxidant, radical scavenging activity and polyphenolics profile in Solanum torvum L. fruits.

UNLABELLED: Solanum torvum fruit widely used in traditional medicine of India and also in food preparation. Three different extracts such as water (WE), methanol (ME), and ethanol (EE) were used to evaluate their antioxidant and radical scavenging activity by different methods. All the assays results were compared with well-known standard antioxidants. The IC(50) values of assays were determined. The total phenolic and flavonoids content were found to be maximum in water and ethanol extracts, respectively. The electron quenching ability of fruit extract was assayed by DPPH and reducing power assays succeeding order were ME > EE > WE, respectively. Inhibition of membrane damage, was assayed interns of oxidative hemolysis and lipid peroxidation assays, among all WE extract shows 58.00% and 68.55 5% percentage of inhibition with 0.9 and 0.8 correlations (r(2)), respectively. Antioxidant and radical quenching efficiency were assayed by ß-carotene bleaching and hydroxyl radical scavenging method and results were compared with vitamin C and catechin. The in vitro free radical quenching and antioxidant results were well correlated with in vitro DNA protection assay. As analyzed by HPTLC gallic acid content is high in WE (1394 ± 25.0) and ME (598 ± 54.0) whereas ferulic acid is high in EE (32 ± 5.94) µg/g, respectively. This study indicate that S. torvum fruit is an excellent source of natural antioxidant and could be an effective nutritional food supplement, which interns will have therapeutic applications. PRACTICAL APPLICATION: In siddha medicine on the traditional systems of India the, ripened fruits are used in the preparation of tonic named as a "sundaivattaral choornam" is used to improve the health and prevent several diseases. This study has given an experimental evidence that S. torvum fruit is an excellent source of natural antioxidants.