Green Emitting Cerium Doped CaS Whiskers Grown by Solid State Diffusion Method

Undoped and cerium doped Calcium sulfide (CaS) phosphors were synthesized using solid state diffusion method. The X-ray diffraction pattern revealed that both undoped and doped CaS crystallites have cubic structure with average crystallite size varying from 20 to 30 nm. Scanning electron micrographs indicated that Ce doped CaS phosphors were composed of whiskers with different dimensions and orientations. The optical properties of undoped and Ce doped particles were characterized using Photoluminescence (PL) and UV-Vis absorption spectroscopy. The PL emission spectrum of cerium doped CaS phosphors for an excitation wavelength 465 nm showed a main peak at 500 nm and a shoulder peak at 556 nm due to 5d?→?4f transition in Ce³⁺ ions. The variation of PL intensity with cerium concentration was investigated and the maximum PL intensity was obtained for a doping concentration of 3 wt.%. The optical band gap of the samples was estimated from the diffuse reflectance spectrum and was found to increase with increase in cerium concentration. The enhanced optical properties of these phosphors can be exploited in various optoelectronic devices including displays and bioimaging techniques.     

Isolation,Characterization, and Medicinal Potential of Polysaccharides of Morchella esculenta

Mushroom polysaccharides are active medicinal compounds that possess immune-modulatory and anticancer properties. Currently, the mushroom polysaccharides krestin, lentinan, and polysaccharopeptides are used as anticancer drugs. They are an unexplored source of natural products with huge potential in both the medicinal and nutraceutical industries. The northern parts of Pakistan have a rich biodiversity of mushrooms that grow during different seasons of the year. Here we selected an edible Morchella esculenta (true morels) of the Ascomycota group for polysaccharide isolation and characterization. Polysaccharopeptides and polysaccharides from this mushroom were isolated using the green chemistry, hot water treatment method. Fourier transform infrared spectroscopy revealed the sugar nature and possible beta-glucan type structure of these polysaccharides. Antioxidant assays showed that the deproteinized polysaccharides have moderate free radical scavenging activity. These isolated polysaccharides exhibited good acetylcholinesterase (AChE) and butyryl cholinesterase (BChE) inhibition activities. Therefore, these polysaccharides may be valuable for the treatment of Alzheimer’s and Parkinson’s diseases. Further bioassays are needed to discover the true potential of M. esculenta polysaccharides for medicinal purposes.     

Structure–property study of waterborne,polyurethane acrylate dispersions based on hyperbranched aliphatic polyester for UV-curable coatings

A series of waterborne, hyperbranched polyurethane acrylates for aqueous dispersions (WHPUDs) based on hydroxy-functionalized hyperbranched aliphatic polyester Boltorn H20 were synthesized and characterized by Fourier transform infrared spectroscopy (FTIR). The aqueous dispersions were electrostatically stabilized with carboxyl groups incorporated into their structures, which were neutralized by triethylamine (TEA). The effects of chemical structures of end groups on various properties of WHPUDs, such as particle size, interfacial tension, and rheological behavior were investigated. The average particle sizes of aqueous dispersions, 43–237 nm, were determined by laser light scattering. Owing to the enlargement of the stabilization site, the particle size decreased as the content of carboxyl group, degree of neutralization, and dielectric constant of the dispersion medium increased. Moreover, the surface tension of aqueous dispersions of WHPUDs decreased as the TEA/COOH mole ratio and degree of neutralization increased. The investigations of the rheological behavior of the WHPUDs suggested that all the dispersions belong to pseudoplastic fluids, and each of them has viscosity much lower compared with the commercial water-based resin EB 2002.     

Reactions of ring-expanded xanthines containing the imidazo[4,5-e][1,4]diazepine ring system

4,5,7,8-Tetrahydro-6H-imidazo[4,5-e][1,4]diazepine-5,8-dione underwent bromination at the 2-position with or without substituents at the 3-, 4- or 7-position, using bromine, N-bromosuccinimide, or acetyl hypobro-mite. The activation of position 6 with an ester functionality, as in 7 , did not alter the site of bromination. The base-catalyzed bromination of the ring-open precursor, diethyl 2-[N-(1-benzyl-5-nitroimidazolyl-4-carbon-yl)amino]malonate ( 5 ), resulted either in introduction of an alkoxy functionality in the above aminomalonate side-chain, yielding 17 when the reaction was quenched with an alcohol, or in degradation of the side-chain, yielding 1-benzyl-5-nitroimidazole-4-carboxamide ( 19 ) when the reaction was quenched with water. Both 17 and 19 are formed by oxidative bromination of 5 via the bromo intermediate 15 . An indirect evidence for the latter was obtained by base-catalyzed methylation of 5 which gave diethyl 2-methyl-2-[N-(1-benzyl-5-nitroimid-azolyl-4-carbonyl)amino]malonate ( 21 ). The base-catalyzed bromination of 5 with N-bromosuccinimide gave rise to two products, the dimer 24a and the monomer 24b that contained the substituted 2,2-diaminomalon-ate side-chain. The structure of 24b was confirmed by single-crystal X-ray diffraction analyses. Reduction of the 5-nitro group of 17 to the corresponding amino derivative 25 , followed by ring-closure with sodium meth-oxide/methanol, yielded three products, a 5:6-fused system 26 and two 5:7 fused systems 27 and 28 . The structures of 26 and 27 were confirmed by single-crystal X-ray diffraction analyses. A tentative reaction pathway for the formation of all three products has been proposed. Hydrolysis of 27 with aqueous hydrochloric acid resulted in ring-opening to form 5-amino-1-benzylimidazole-4-carboxamide ( 40 ). A mechanism for the hydrolysis reaction has been proposed. Catalytic hydrogenation of 5 in acetic acid yielded the aminoimidazo-lone derivative 11 which upon ring-closure with sodium methoxide in methanol produced imidazo[4,5-e][1,4]-diazepine-2,5,8-trione ( 12 ).     

Applications of fuzzy linear programming with generalized LR flat fuzzy parameters

In this paper, the limitations of existing methods to solve the problems of fuzzy assignment, fuzzy travelling salesman and fuzzy generalized assignment are pointed out. All these problems can be formulated in linear programming problems wherein the decision variables are represented by real numbers and other parameters are represented by fuzzy numbers. To overcome the limitations of existing methods, a new method is proposed. The advantage of proposed method over existing methods is demonstrated by solving the problems mentioned above which can or cannot be solved by using the existing methods.     

α-Axis oriented ZnS thin film synthesised by dip coating method

The structural, morphological, optical and electrical properties of α-axis oriented nanostructured ZnS thin film prepared by dip coating have been studied in this article. The X-ray diffraction studies of the film shows that the ZnS was crystallized with cubic structure of particle size 27 nm with a strong orientation along (200) plane which is advantageous for optoelectronic devices. The scanning electron microscopy and TEM micrograph reveals that the film consists of nano crystalline columnar particles. From the investigation of the absorption spectra of this ZnS film, the band-gap is found to be higher (4 eV) than bulk (3.7 eV) indicating a blue shift. It is found that the film is having a transparency of >90 % in the visible-near IR region from 400 to 800 nm. From the photoconductivity measurements, it is evident that the film is photosensitive in nature. From the electrical resistivity measurements the conductivity of the film was found to be 3.4 × 10^?2 Ω^?1 cm^?1. Hot probe method indicates that the synthesized ZnS film is n-type.     

Mehar’s method to find exact fuzzy optimal solution of unbalanced fully fuzzy multi-objective transportation problems

To the best of our knowledge, till now there is no method described in literature to find exact fuzzy optimal solution of balanced as well as unbalanced fully fuzzy multi-objective transportation problems. In this paper, a new method named as Mehar??s method, is proposed to find the exact fuzzy optimal solution of fully fuzzy multi-objective transportation problems (FFMOTP). The advantages of the Mehar??s method over existing methods are also discussed. To show the advantages of the proposed method over existing methods, some FFMOTP, which cannot be solved by using any of the existing methods, are solved by using the proposed method and the results obtained are discussed. To illustrate the applicability of the Mehar??s method, a real life problem is solved.     

On the construction of some bioconjugate networks and their structural modeling via irregularity topological indices

The European Physical Journal E - In this article, we experimentally investigate the nonlinear behaviour of a viscoplastic film flow down an inclined plane. We focus on the nonlinear instabilities...