Performance of an optical wideband WDM system considering stimulated Raman scattering,fiber attenuation and chromatic dispersion

The performance of an optical wideband wavelength division multiplexed (WDM) communication system is analyzed considering the effects of stimulated Raman scattering, fiber attenuation and chromatic dispersion. Improved models for the Raman gain and the fiber attenuation constant are proposed, which yield better and reliable performance results of the WDM system. Effect of fiber chromatic dispersion is also investigated and it is observed that dispersion can suitably be selected to overcome the limitations imposed by the stimulated Raman scattering phenomenon.     

Energy localization and transport in two-dimensional Fermi–Pasta–Ulam lattices

We investigate energy localization and transport in the form of discrete breathers and their movability in two-dimensional Fermi–Pasta–Ulam(FPU) lattices. We study the dynamics of the two-dimensional Fermi–Pasta–Ulam(FPU) lattice, incorporating the complicated effects of geometry, long-range interactions as well as nonlinear dispersion. We obtain several exact discrete breather(DB) solutions, such as the odd-parity and even-parity DBs, compact-like DBs and moving DBs for various geometries of the two-dimensional FPU chain. We show that DBs also exist in the same lattice in presence of next-nearest neighbour interaction. Large-amplitude exact subsonic travelling kink-soliton solutions are obtained in such a periodic chain in presence of long-range nonlinear dispersive interaction in the long-wavelength and weakly nonlinear limit. Such a two-dimensional FPU lattice admits finite amplitude nonlinear sinusoidal wave (NSW) solutions with short commensurate as well as incommensurate wavelengths for different geometries of the chain. The usefulness of these solutions for energy localization and transport in various physical systems are discussed.     

Effects of barrier fluctuation on the tunneling dynamics in the presence of classical chaos in a mixed quantum-classical system

We present a numerical investigation of the tunneling dynamics of a particle moving in a bistable potential with fluctuating barrier which is coupled to a non-integrable classical system and study the interplay between classical chaos and barrier fluctuation in the tunneling dynamics. We found that the coupling of the quantum system with the classical subsystem decreases the tunneling rate irrespective of whether the classical subsystem is regular or chaotic and also irrespective of the fact that whether the barrier fluctuates or not. Presence of classical chaos always enhances the tunneling rate constant. The effect of barrier fluctuation on the tunneling rate in a mixed quantum-classical system is to suppress the tunneling rate. In contrast to the case of regular subsystem, the suppression arising due to barrier fluctuation is more visible when the subsystem is chaotic.      

A FLUORESCENCE LIFETIME ASSAY OF A MEMBRANE-BOUND FLAVIN FROM CORN COLEOPTILES

Abstract— The fluorescence lifetime of a partially-purified membrane fraction containing flavin and b-type cytochrome, presumably on the same protein, has been described. Possible implications of the blue light photoreactivity of the flavin as an assay, on the basis of its short fluorescence lifetime (about 1.37 ns), has been discussed.     

Towards "designer" surfaces: functionalisation of self-assembled monolayer (SAM) on colloidal gold by alkene metathesis

A variety of groups like a Fischer carbene complex, an N-hydroxysuccinimide or a ferrocene derivative have been grafted by ruthenium-catalyzed cross-metathesis reaction with terminal alkene groups on monolayer-protected gold clusters as a mild and convenient strategy to anchor functional molecules.     

Remotely controlled electro-responsive on-demand nanotherapy based on amine-modified graphene oxide for synergistic dual drug delivery

This study focuses on the development of a new electric field responsive graphene oxide (GO) nanoparticle system for on-demand drug delivery. Today, GO is an attractive option adopted in various biological applications for its exclusive features such as flexibility, conductiveness, cost-effectiveness, and external stimuli-responsive nature. It is usual to utilize multiple drugs in cancer treatment. This kind of therapy has lesser side-effects, drug resistance, and is more effective than utilizing only one drug. This study aims to determine low-voltage-controlled dual drug (aspirin and doxorubicin) release from GO surface. Here, we have demonstrated how to control the drug release rate remotely with a handy mobile phone, with zero passive release at idle time. In addition, the study focused to estimate the synergism of aspirin with doxorubicin in the release mechanism from GO in the presence of external voltage, using the spectroscopic method. Moreover, we observed aspirin- and doxorubicin-induced synergistic antitumor activity in MDA-MB 231 (breast cancer cell) in vitro. Thus, our study presents a noble combination of aspirin and doxorubicin that could be utilized for remotely controlled on-demand drug delivery for triple negative breast cancer treatment, using GO as a carrier.     

Optimizing the degradation of dichlorvos in aqueous solution using nZVI DTPA+H2O2 and its detection using ac conductivity measurement with the help of response surface methodology

Degradation of organic pollutants in wastewater is a common subject of discussion under advanced oxidation process. To detect the degradation of colourless organic pollutants conventional analytical techniques are available but their sophistication makes it difficult to pursue in all form of chemical laboratories. In the present study it was found that during degradation of Dichlorvos using diethylene triamine pent acetic acid (DTPA) stabilized nano zero valent iron (nZVI), COD removal and ac conductivity change has been done simultaneously. In this degradation study the heterogeneous Fenton type oxidation method was employed and an LCR circuit (which contains inductor, capacitor and resistor) was used to measure the ac conductivity. This study aims to find out a correlation between ac conductivity and COD removal using simple response surface methodology (RSM) so that the degradation of colourless pollutants can be estimated easily and also to identify the best processing parameters to optimise Dichlorvos degradation. It was found that COD removal in most of all cases, was more than 60% when the change in final ac conductivity more than 600% with respect to initial value. All of the experimental results were in good accord with the projected outcome.