Preparation and Study of Some Copolyesters

Terephthalate unsaturated copolyesters with ethylene glycol and 2-butene-1,4-diol, with ethylene glycol and 2-butyne-1,4-diol, with ethylene glycol and diethylene glycol, and with 2-butyne-1,4-diol were synthesized by trans-esterification reactions. Proton nuclear magnetic resonance spectroscopy was used to elucidate the structures of the copolyesters. The intrinsic viscosities of the copolyesters were measured in o-chlorophenol at 30°C. The number-average molecular weights of these copolyesters were determined by using a vapor pressure osmometer. The thermal behaviors of the copolyesters were studied by differential thermal analysis and are discussed in terms of structural differences.     

Regulation of heat transfer in Rayleigh–Bénard convection in Newtonian liquids and Newtonian nanoliquids using gravity,boundary temperature and rotational modulations

Journal of Thermal Analysis and Calorimetry - The individual effect of time-periodic gravity modulation, in-phase and out-of-phase temperature modulations and rotational modulation on...     

Studies on ultrasonic properties of different series of liquid systems

Fifteen specimens of tetraalkoxysilanes were prepared and their tentative tetrahedral structures proposed. Ultrasonic velocities were measured over the temperature range of 30–80°C using a multifrequency ultrasonic interferometer. Intermolecular free length, free volume and internal pressure of different classes of compounds were evaluated using the experimentally determined ultrasonic velocity, density, specific heat, thermal expansion, viscosity and molecular weight employing different empirical equations and the data obtained were compared.     

Maximal Area Integral Problem for Certain Class of Univalent Analytic Functions

One of the classical problems concerns the class of analytic functions f on the open unit disk |z| < 1 which have finite Dirichlet integral Δ(1, f), where

$$\Delta(r ,f) = \iint_{|z| < r} |f' (z)| ^ 2 \, {\rm d} x {\rm d}y \quad (0 < r \leq 1)$$

The class \({\mathcal{S} ^*(A,B)}\) of normalized functions f analytic in |z| < 1 and satisfies the subordination condition \({zf'(z)/f(z)\prec (1+Az)/(1+Bz)}\) in |z| < 1 and for some \({-1\leq B\leq 0}\) , \({A \in \mathbb{C}}\) with \({A\neq B}\) , has been studied extensively. In this paper, we solve the extremal problem of determining the value of

$$\max_{f\in \mathcal{S}^*(A,B)}\Delta(r,z/f)$$

as a function of r. This settles the question raised by Ponnusamy and Wirths (Ann Acad Sci Fenn Ser AI Math 39:721–731, 2014). One of the particular cases includes solution to a conjecture of Yamashita which was settled recently by Obradovi? et al. (Comput Methods Funct Theory 13:479–492, 2013).

     

Absolutely convex,uniformly starlike and uniformly convex harmonic mappings

In this paper, we prove necessary and sufficient conditions for a sense-preserving harmonic function to be absolutely convex in the open unit disc. We also estimate the coefficient bound and obtain growth, covering and area theorems for absolutely convex harmonic mappings. A natural generalization of the classical Bernardi-type operator for harmonic functions is considered and its connection between certain classes of uniformly starlike harmonic functions and uniformly convex harmonic functions is also investigated. At the end, as applications, we present a number of results connected with hypergeometric and polylogarithm functions.     

A mild and efficient CAN mediated oxidation of Morita-Baylis-Hillman adducts of 5-methyl-N-alkylisatin to 5-formyl-N-alkylisatin

A simple, mild and efficient CAN mediated oxidation of Morita-Baylis-Hillman adducts of 5-methyl-N-alkylisatins 1a-13a to 5-formyl-N-alkylisatins 1b-13b under ambient reaction conditions is reported. Simple and isomerized 5-methyl-N-alkylisatin derivatives 1-4 have also been tested and failed to provide the corresponding formylated products. A plausible reaction mechanism has been proposed.     

Circular symmetrization,subordination and arclength problems on convex functions

We study the class of univalent analytic functions f in the unit disk of the form satisfying where Ω will be a proper subdomain of which is starlike with respect to . Let be the unique conformal mapping of onto Ω with and and . Let denote the arclength of the image of the circle , . The first result in this paper is an inequality for , which solves the general extremal problem , and contains many other well‐known results of the previous authors as special cases. Other results of this article cover another set of related problems about integral means in the general setting of the class .     

Chemometrics-assisted cross injection analysis for simultaneous determination of phosphate and silicate

This work presents a novel method for simultaneous spectrophotometric determination of phosphate and silicate by using a cross injection analysis (CIA) coupled with the use of partial least squares (PLS) for data evaluation. The detection principle is based on the well-known ‘molybdenum blue’ method. The molybdate ions in the presence of stannous chloride in acidic medium give phosphomolybdenum blue and silicomolybdenum blue as products. In this work, all the liquids, including sample and reagents were simultaneously introduced into a CIA platform by using two peristaltic pumps for controlling the x-channel and y-channel flow which was automatically manipulated by using in-house control board. Crossflow provides sufficient mixing inside the platform prior detection of the absorption spectra of blue complexes in the wavelength of 400–900 nm. Since spectra of the blue colour product of phosphate and silicate are resemblant, these two analytes therefore reciprocally interfere with one another. This results in difficulty in simultaneous analysis of phosphate and silicate. In this work, PLS was utilised as assistor of CIA system for simultaneous analysis of phosphate and silicate using molybdenum blue reaction without using any modification of reagents and addition of selective masking agent. The calibration ranges are 0.1–6 mgP L^?1 and 5–100 mgSi L^?1 for phosphate and silicate, respectively. By using CIA coupled with PLS for data evaluation, the analysis of two analytes was achieved within 1.5 min with only single injection. The developed system was applied to natural water samples and the system was validated with the conventional methods. By statistical paired t-test, there was no evidence of significant difference at 95% confidence level (t_stat = 2.28, t_critical = 2.31 and t_stat = 0.62, t_critical = 2.31 for phosphate and silicate, respectively). This implied that the chemometrics-assisted CIA system was successfully developed for simultaneous spectrophotometric determination of phosphate and silicate.     

Synthesis of novel functionalized 3-spiropyrrolizidine and 3-spiropyrrolidine oxindoles from Baylis-Hillman adducts of isatin and heteroaldehydes with azomethine ylides via [3+2]-cycloaddition

A novel regioselective synthesis of a number of functionalized 3-spiropyrrolizidine and 3-spiropyrrolidine oxindoles from Baylis-Hillman adducts of isatin and heteroaldehydes via [3+2] cycloaddition of azomethine ylides in excellent yields has been reported.     

Synthesis,structural, DFT investigations and antibacterial activity assessment of pyrazoline-thiocyanatoethanone derivatives as thymidylate kinase inhibitors

Two novel compounds 1-(5-[4-fluorophenyl]-3-phenyl-4,5-dihydro-1H-pyrazol-1-yl)-2-thiocyanatoethanone (FSCN) and 1-(5-[4-chlorophenyl]-3-phenyl-4,5-dihydro-1H-pyrazol-1-yl)-2-thiocyanatoethanone (ClSCN) were synthesized and characterized by SC-XRD, 1H NMR, 13C NMR, FTIR, and UV methods. The X-ray diffraction studies were utilized to prove the 3D crystal structures of FSCN and ClSCN. In both the compounds, the packing is mostly driven by C H⋯N, C H⋯O, and C H⋯π (benzene ring as an acceptor) interactions. In ClSCN, additionally, the π⋯π interaction is observed between the pyrazole ring of one molecule and the benzene ring of the other molecule. The experimental values were compared with the results of DFT/B3LYP/6-311G++(d,p) theoretical computations. The pharmacological screening for FSCN and ClSCN was performed using molinspiration and PreADMET web server. To analyze antibacterial inhibition of the synthesized ligands and Ciprofloxacin (control drug) were interacted with antibacterial protein Thymidylate Kinase (TMK) (PDB ID: 4QGG) with the help of AutoDock Vina tool. The ADMET and docking results of FSCN and ClSCN pointed out the better drug likeness nature and good inhibition behavior with TMK protein. The antibacterial in vitro studies suggested that FSCN compound inhibited well with antibacterial strains than that of ClSCN. The current investigation suggests that with further improvements, our compounds could be preferred as substitute medicine for bacterial diseases.