SYNTHESIS, CHARACTERIZATION AND EVALUATION OF ANTICANCER ACTIVITY OF SOME NEW SCHIFF BASES OF 1, 3, 4-THIADIAZOLE DERIVATIVES

Objective: N-benzylidene-5-phenyl-1, 3, 4-thiadiazol-2-amine derivatives: Synthesis and anticancer activity.Methods: In the present study five new derivatives of N-benzylidene-5-phenyl-1, 3, 4-thiadiazol-2-amine (Schiff bases containing 1, 3, 4-thiadiazole) were synthesized according to the literature methods and were characterized by FT-IR, 1H NMR spectroscopy and C, H, N analysis. Anticancer activity was evaluated in Male Swiss albino mice using Ehrlich's Ascites carcinoma cells. Compounds were administered at a dose of 25 mg/kg, body weight intraperitoneally.Results: The compounds were found to reduce tumor volume, viable cell count and increase the tumor weight (%) inhibition, ascites cells (%) inhibition, non-viable cell count and increase in life span (%ILS). All the compounds exhibited significant (P< 0.01) anticancer activity compared to control and the compound 2d & 4d was found to be most potent.Conclusion: It is concluded that synthesized Schiff bases of 2-amino-5-aryl-1, 3, 4-thiadiazoles derivatives are biologically active and developed into useful anticancer agents.Â

Development and characterizations ofultra-highmolecular weightEPDM/PPbasedTPVnanocomposites for automotive applications

This research article reports, the preparation of thermoplastic vulcanizates (TPVs) and TPV nanocomposites (TPVNs) based on EPDM and polypropylene (PP). New generation ultra-high molecular weight EPDM (UHMW-EPDM) and PP with nano-fillers (nano-clay and nano-silica) and has been studied and characterized extensively typically for automotive applications. This special type of UHM-EPDM-based TPVs exhibit superior physico-mechanical properties over conventional EPDM-based TPVs and in the presence of nano-fillers, they show even better physical properties. The TPVNs were prepared with a fixed EPDM: PP ratio and the nano fillers were varied at different concentrations. The influence of nano-fillers, especially hectorite nano-clay and nano-silica has been first explored through physico-mechanical properties. Tensile strength, elongation at break, and modulus at various strain are improved for nano-filler filled TPVNs. We have observed that due to the incorporation of nano-fillers into the TPV matrix, swelling has been decreased. From morphology (AFM, SEM) study, it is observed that the fillers are well dispersed in the TPV matrix and nano-silica fillers are well dispersed than nano-clay (hectorite). Furthermore, small-angle X-ray scattering (SAXS) studies have also been pursued to get a better insight into the TPV system. These newly developed TPVs can be used as potential candidates for application in the automotive sector

Cosmological evolution of interacting phantom (quintessence) model in Loop Quantum Gravity

The dynamics of interacting dark energy model in loop quantum cosmology (LQC) is studied in this paper. The dark energy has a constant equation of state $w_x$ and interacts with dark matter through a form $3cH(\rho_x+\rho_m)$. We find for quintessence model ($w_x>-1$) the cosmological evolution in LQC is the same as that in classical Einstein cosmology; whereas for phantom dark energy ($w_x<-1$), although there are the same critical points in LQC and classical Einstein cosmology, loop quantum effect reduces significantly the parameter spacetime ($c, w_x$) required by stability. If parameters $c$ and $w_x$ satisfy the conditions that the critical points are existent and stable, the universe will enter an era dominated by dark energy and dark matter with a constant energy ratio between them, and accelerate forever; otherwise it will enter an oscillatory regime. Comparing our results with the observations we find at $1\sigma$ confidence level the universe will accelerate forever.Comment: 15 pages, 8 figures, to appear in JCA

Scalar field exact solutions for non-flat FLRW cosmology: A technique from non-linear Schr\"odinger-type formulation

We report a method of solving for canonical scalar field exact solution in a non-flat FLRW universe with barotropic fluid using non-linear Schr\"{o}dinger (NLS)-type formulation in comparison to the method in the standard Friedmann framework. We consider phantom and non-phantom scalar field cases with exponential and power-law accelerating expansion. Analysis on effective equation of state to both cases of expansion is also performed. We speculate and comment on some advantage and disadvantage of using the NLS formulation in solving for the exact solution.Comment: 12 pages, GERG format, Reference added. accepted by Gen. Relativ. and Gra

A Quintessentially Geometric Model

We consider string inspired cosmology on a solitary $D3$-brane moving in the background of a ring of branes located on a circle of radius $R$. The motion of the $D3$-brane transverse to the plane of the ring gives rise to a radion field which can be mapped to a massive non-BPS Born-Infeld type field with a cosh potential. For certain bounds of the brane tension we find an inflationary phase is possible, with the string scale relatively close to the Planck scale. The relevant perturbations and spectral indices are all well within the expected observational bounds. The evolution of the universe eventually comes to be dominated by dark energy, which we show is a late time attractor of the model. However we also find that the equation of state is time dependent, and will lead to late time Quintessence.Comment: 11 pages, 3 figures. References and comments adde

Coupled dark energy: Towards a general description of the dynamics

In dark energy models of scalar-field coupled to a barotropic perfect fluid, the existence of cosmological scaling solutions restricts the Lagrangian of the field \vp to p=X g(Xe^{\lambda \vp}), where X=-g^{\mu\nu} \partial_\mu \vp \partial_\nu \vp /2, $\lambda$ is a constant and $g$ is an arbitrary function. We derive general evolution equations in an autonomous form for this Lagrangian and investigate the stability of fixed points for several different dark energy models--(i) ordinary (phantom) field, (ii) dilatonic ghost condensate, and (iii) (phantom) tachyon. We find the existence of scalar-field dominant fixed points (\Omega_\vp=1) with an accelerated expansion in all models irrespective of the presence of the coupling $Q$ between dark energy and dark matter. These fixed points are always classically stable for a phantom field, implying that the universe is eventually dominated by the energy density of a scalar field if phantom is responsible for dark energy. When the equation of state w_\vp for the field \vp is larger than -1, we find that scaling solutions are stable if the scalar-field dominant solution is unstable, and vice versa. Therefore in this case the final attractor is either a scaling solution with constant \Omega_\vp satisfying 0<\Omega_\vp<1 or a scalar-field dominant solution with \Omega_\vp=1.Comment: 21 pages, 5 figures; minor clarifications added, typos corrected and references updated; final version to appear in JCA

Curvaton Dynamics in Brane-worlds

We study the curvaton dynamics in brane-world cosmologies. Assuming that the inflaton field survives without decay after the end of inflation, we apply the curvaton reheating mechanism to Randall-Sundrum and to its curvature corrections: Gauss-Bonnet, induced gravity and combined Gauss-Bonnet and induced gravity cosmological models. In the case of chaotic inflation and requiring suppression of possible short-wavelength generated gravitational waves, we constraint the parameters of a successful curvaton brane-world cosmological model. If density perturbations are also generated by the curvaton field then, the fundamental five-dimensional mass could be much lower than the Planck massComment: 47 pages, 1 figure, references added, to be published in JCA

Loop Quantum Cosmology: A Status Report

The goal of this article is to provide an overview of the current state of the art in loop quantum cosmology for three sets of audiences: young researchers interested in entering this area; the quantum gravity community in general; and, cosmologists who wish to apply loop quantum cosmology to probe modifications in the standard paradigm of the early universe. An effort has been made to streamline the material so that, as described at the end of section I, each of these communities can read only the sections they are most interested in, without a loss of continuity.Comment: 138 pages, 15 figures. Invited Topical Review, To appear in Classical and Quantum Gravity. Typos corrected, clarifications and references adde

An overview of anti-diabetic plants used in Gabon: Pharmacology and Toxicology

© 2017 Elsevier B.V. All rights reserved.Ethnopharmacological relevance: The management of diabetes mellitus management in African communities, especially in Gabon, is not well established as more than 60% of population rely on traditional treatments as primary healthcare. The aim of this review was to collect and present the scientific evidence for the use of medicinal plants that are in currect by Gabonese traditional healers to manage diabetes or hyperglycaemia based here on the pharmacological and toxicological profiles of plants with anti-diabetic activity. There are presented in order to promote their therapeutic value, ensure a safer use by population and provide some bases for further study on high potential plants reviewed. Materials and methods: Ethnobotanical studies were sourced using databases such as Online Wiley library, Pubmed, Google Scholar, PROTA, books and unpublished data including Ph.D. and Master thesis, African and Asian journals. Keywords including ‘Diabetes’ ‘Gabon’ ‘Toxicity’ ‘Constituents’ ‘hyperglycaemia’ were used. Results: A total of 69 plants currently used in Gabon with potential anti-diabetic activity have been identified in the literature, all of which have been used in in vivo or in vitro studies. Most of the plants have been studied in human or animal models for their ability to reduce blood glucose, stimulate insulin secretion or inhibit carbohydrates enzymes. Active substances have been identified in 12 out of 69 plants outlined in this review, these include Allium cepa and Tabernanthe iboga. Only eight plants have their active substances tested for anti-diabetic activity and are suitables for further investigation. Toxicological data is scarce and is dose-related to the functional parameters of major organs such as kidney and liver. Conclusion: An in-depth understanding on the pharmacology and toxicology of Gabonese anti-diabetic plants is lacking yet there is a great scope for new treatments. With further research, the use of Gabonese anti-diabetic plants is important to ensure the safety of the diabetic patients in Gabon.Peer reviewedFinal Accepted Versio