A benzthiazole-based tripodal chemosensor for Ba recognition under biological conditions

We synthesized a benzthiazole-based chemosensor with mixed S,N donor sites. The binding units are incorporated in a highly flexible tripodal framework which facilitates the complexation of the binding of larger-sized metals. The chemosensor resulted in the sensitive and selective recognition of Ba²⁺ through the enhancement of the fluorescence intensity when studied in a THF/H₂O (8:2, v/v) solvent mixture. The sensor offers an interesting opportunity to monitor Ba²⁺ in biological samples including the cytoplasm of microbes such as Saccharomyces cerevisiae.     

Thermodynamics of binary liquid mixtures of cyclopentane with 2-propanol, 1-butanol and 2-butanol at different temperatures

Densities and speeds of sound of the cyclopentane with 2-propanol, 1-butanol and 2-butanol are measured over the whole composition range at different temperatures in the range 288.15–308.15 K and atmospheric pressure using Anton Paar DSA 5000 densimeter. The experimental densities and speeds of sound have been used to calculate excess molar volumes, excess molar isentropic compressibilities and excess intermolecular free length. The partial molar volumes and apparent molar volumes at infinite dilution have also been calculated. The mixing quantities like (∂V _m^E/∂T)_P and (∂H _m^E/∂P)_T have been calculated at T = 298.15 K and these values are compared with the values calculated from Flory’s theory at equimolar composition.     

A new method for solving fully fuzzy linear programming problems

Lotfi et al. [Solving a full fuzzy linear programming using lexicography method and fuzzy approximate solution, Appl. Math. Modell. 33 (2009) 3151–3156] pointed out that there is no method in literature for finding the fuzzy optimal solution of fully fuzzy linear programming (FFLP) problems and proposed a new method to find the fuzzy optimal solution of FFLP problems with equality constraints. In this paper, a new method is proposed to find the fuzzy optimal solution of same type of fuzzy linear programming problems. It is easy to apply the proposed method compare to the existing method for solving the FFLP problems with equality constraints occurring in real life situations. To illustrate the proposed method numerical examples are solved and the obtained results are discussed.     

Integrability and <Emphasis Type="Italic">L</Emphasis><Superscript>1</Superscript>-convergence of double cosine trigonometric series

We study here L1-convergence of new modified double cosine trigonometric sum and obtain a new necessary and sufficient condition for L1-convergence of double cosine trigonometric series.Also,the results obtained by Moricz[1],[2] are particular cases of ours.     

Enhancing the pedagogy of mathematics teachers (EPMT) project: a hybrid model of professional development

Enhancing the pedagogy of mathematics teachers (EPMT) project is a hybrid model of professional development (PD) that reflects a gradual shift in the centre of gravity away from the University-based, “supply-side”, “off-line” forms of knowledge production conducted by university scholars for teachers towards an emergent school-based, demand-side, on-line, in situ forms of knowledge production conducted by teachers with support from university scholars. The aims of the EPMT project were threefold: to provide teachers with training, to facilitate teachers’ work (practice and feedback) at the school level and to enthuse and support teachers to contribute towards the development of fellow teachers. This paper examines two project participants’ infusion of their learning in classroom practice. From the lessons enacted by the two teachers it was apparent that both teachers were able to apply their learning in their lessons. The teachers also manifested changes in their perception of teaching mathematics.     

Steady state self-focusing, self-modulation of laser beam in an inhomogeneous plasma

Laboratory as well as PIC simulation experiments reveal strong flow of energetic electrons co-moving with laser beam in laser plasma interaction. Equation governing the evolution of complex envelope in slowly varying envelope approximation is nonlinear parabolic equation. Variational approach is used to solve this problem and a Lagrangian for the problem is set up. Assuming a trial Gaussian profile, authors solve the reduced Lagrangian problem for beam width and curvature. Two scale lengths for inhomogenity along the direction of propagation, one for nonlinearity and other for diffraction management are introduced. Self-focusing, self-modulation as well as self-trapping of the laser-electron-beam plasma system is studied under variety of parameters.     

VO2-WO3 nanocomposite thin films synthesized by pulsed laser deposition technique

Pure VO₂ and VO₂-WO₃ composite thin films were grown on quartz substrate by pulsed laser deposition (PLD) technique. The influence of varying WO₃ molar concentration in the range from x = 0.0 to x = 0.4 on structural, electrical and optical properties of VO₂-WO₃ nanocomposite thin films has been systematically investigated. X-ray diffraction studies reveal the single crystalline monoclinic VO₂ phase (m-VO₂) up to 10% of WO₃ content whereas both m-VO₂ as well as h-WO₃ (hexagonal WO₃) phases were present at higher WO₃ content (0.2 ≤ x ≤ 0.4). Optical transmittance spectra of the films showed blue shift in the absorption edge with increase in WO₃ content. Temperature dependence of resistivity (R-T) measurements indicates significant variation in metal-insulator transition temperature, width of the hysteresis, and shape of the hysteresis curve. Cyclic Voltammetry measurements were performed on VO₂-WO₃ thin films. A direct correlation between V/W ratio and structure-property relationship was established. The present investigations reveal that doping of WO₃ in VO₂ is effective to increase the optical transmittance and to reduce the semiconductor to metal phase transition temperature close to room temperature.     

Synthesis and Evaluation of Surface Active Properties of Ester-Based Cationic Imidazolium Monomeric Surfactants

New imidazolium cationic surfactants have been synthesized by esterification of halogenated carboxylic acids with long-chain fatty alcohols furnishing respective esters (dodecyl-2-chloroacetate, tetradecyl-2-chloroacetate, hexadecyl-2-chloroacetate, dodecyl-2-bromoacetate, tetradecyl-2-bromoacetate, and hexadecyl-2-bromoacetate) followed by their subsequent treatment with 1-trifluoro acetyl imidazole resulting into the formation of title monomeric surfactants: 3-(2-(hexadecyloxy)-2-oxoethyl)-1-(2,2,2-trifluoroacetyl)-1H-imidazol-3-ium chloride (7); 3-(2-(tetradecyloxy)-2-oxoethyl)-1-(2,2,2-trifluoroacetyl)-1H-imidazol-3-ium chloride (8); 3-(2-(dodecyloxy)-2-oxoethyl)-1-(2,2,2-trifluoroacetyl)-1H-imidazol-3-ium chloride (9); 3-(2-(hexadecyloxy)-2-oxoethyl)-1-(2,2,2-trifluoroacetyl)-1H-imidazol-3-ium bromide (10); 3-(2-(tetradecyloxy)-2-oxoethyl)-1-(2,2,2-trifluoroacetyl)-1H-imidazol-3-ium bromide (11) and 3-(2-(dodecyloxy)-2-oxoethyl)-1-(2,2,2-trifluoroacetyl)-1H-imidazol-3-ium bromide (12). Their identifications are based on IR, ¹H, ¹³C NMR, DEPT, and mass spectral studies. The dynamics of surface activity of these surfactants have also been investigated in the presence of sodium halides (NaCl and NaBr) by surface tension measurement. A series of useful parameters like critical micelle concentration (cmc), surface tension at the cmc (γ_cmc), adsorption efficiency (pC₂₀), effectiveness of surface tension reduction (Π_cmc), Gibbs free energy of the micellization (ΔG_0mic), and Gibbs free energy of adsorption (ΔG_0ads) have been determined from the measurements obtained by surface tension and conductivity method. Further with the application of the Gibbs adsorption isotherm, maximum surface excess concentration (Γ_max), and minimum surface area/molecule (A_min) at the air-water interface were also estimated. Thermal stability of these long-chain cationics have been measured by thermal gravimetric analysis under nitrogen atmosphere. Analysis of thermal stability measurement indicated that the thermal stability of these long-chain imidazoliums increase with an increase in chain length.     

Biotransformation of Rice Bran to Ferulic Acid by Pediococcal Isolates

Ferulic acid (FA) is widely used in foods, in beverages, and in various pharmaceutical industries as a precursor of vanillin. FA biotransformation can occur during the growth of lactic acid bacteria (LAB), and its conversion to other phenolic derivatives is observed by many scientists, where ferulic acid esterase (FAE) and ferulic acid decarboxylase (FDC) play significant roles. The present study aimed at screening a panel of LAB for their ability to release FA from rice bran, an agro waste material. FAE and FDC activities were analyzed for the preliminary screening of various dairy isolates. Two Pediococcus acidilactici isolates were selected for studying further the hydrolysis of FA from rice bran and its bioconversion into phenolic derivatives like 4-ethylphenol, vanillin, vanillic acid, and vanillyl alcohol. P. acidilactici M16, a probiotic isolate, has great potential for the production of FA from rice bran and could be exploited as starter culture in the food industry for the production of biovanillin.     

Thermoluminescence study of ZnS:Cu nanoparticles

In this paper, we report on the TL glow curves and kinetic parameters, activation energy, order of kinetics, and the frequency factor of copper-doped zinc sulfide nanophosphor under UV irradiations. The sample was prepared by the chemical precipitation method; thereafter, the TL glow curves were recorded for different doses of UV exposure at a heating rate of 10 °C/s. The synthesized nanophosphor exhibited TL glow peaks at 241, 255, and 281 °C for the heating rate 10 °C/s at different doses of 5, 10, and 15 min of UV exposure. The kinetic parameters activation energy E, the order of kinetics b, and the frequency factor S of synthesized nanophosphor of ZnS:Cu have been calculated by using a peak shape method while the trap depth was determined using different formulae. The sample was characterized by XRD (X-ray diffraction) and SEM (scanning electron microscope).