On molecular topological properties of hex‐derived networks

Topological indices are numerical parameters of a molecular graph, which characterize its topology and are usually graph invariant. In quantitative structure–activity relationship/quantitative structure–property relationship study, physico‐chemical properties and topological indices such as Randić, atom–bond connectivity (ABC), and geometric–arithmetic (GA) index are used to predict the bioactivity of chemical compounds. Graph theory has found a considerable use in this area of research. In this paper, we study hex‐derived networks HDN1(n) and HDN2(n), which are generated by hexagonal network of dimension n and derive analytical closed results of general Randić index R_α(G) for different values of α, for these networks of dimension n. We also compute the general first Zagreb, ABC, GA, ABC₄, and GA₅ indices for these hex‐derived networks for the first time and give closed formulae of these degree‐based indices for hex‐derived networks. Copyright © 2016 John Wiley & Sons, Ltd.     

Efficient copper-catalyzed Sonogashira coupling reactions and simulation studies

A practical copper-catalyzed I-substitutions of alkyl-2-iodobenzoates with alkynes have been developed using Cu powder as a catalyst under solvent, cocatalyst, and base-free conditions. This reaction system is new, facile, efficient, and economical that gives Sonogashira coupling products in excellent yields (up to 97%). The coupled products (A–J) were characterized by CHNS, ¹H NMR, and ¹³C NMR and are found soluble in ethyl acetate and dichloromethane. In addition, simulation studies of A–J were performed with aspulvinone dimethylallyltransferase enzyme and observe good binding affinity. The reported compounds may act as anti-cizmatics, anti-fobic in future and also have the inhibition of aspulvinone dimethylallyltransferase properties to control Alzheimer’s, Schizophrenia, etc. diseases.     

Influence of metal electrodes on c‐axis orientation of AlN thin films deposited by DC magnetron sputtering

Nanocrystalline aluminum nitride (AlN) thin films were deposited on two types of metallic seed layers on silicon substrates, (111) textured Pt and (110) Mo, by reactive DC magnetron sputtering at low temperature (200 °C). Both textured films of Pt and Mo promote nucleation, thereby improving the crystallinity and epitaxial growth condition for AlN thin films. The deposited films were examined by X‐ray diffraction, scanning electron microscopy and atomic force microscopy techniques. The results indicated that the preferred orientation of crystallites greatly depends upon the kinetic energy of the sputtered species (target power) and seed layers used. Furthermore, AlN thin films with c‐axis perpendicular to the substrate grew on both types of metal electrodes at all power levels larger than 100 W. By comparing the structural properties and compressive stresses at perfect c‐axis orientation conditions, it is evident that AlN films deposited on (110) oriented Mo substrates exhibited superior properties as compared with Pt/Ti seed layers. Furthermore, less values of compressive stresses (?3 GPa) as compared with Pt/Ti substrates (?7.08 GPa) make Mo preferentially better candidate to be employed in the field of suspended Micro/Nano ‐ electromechanical systems (MEMS/NEMS) for piezoelectric devices. Copyright © 2017 John Wiley & Sons, Ltd.     

A review on <Superscript>90</Superscript>Y-labeled compounds and biomolecules

The field of therapeutic nuclear medicine is emerging rapidly as choice of treatment in oncology and other cellular malignancies. The growth of this branch of nuclear medicine is greatly facilitated by the introduction of a number of new radiopharmaceuticals and radionuclides. ⁹⁰Y-radiopharmaceuticals have confirmed their worth in medical and clinical areas in a very short span of time. The ⁹⁰Y is a radioisotope widely used for therapeutic purposes and considerable perfection has been made to understand the chemistry of ⁹⁰Y-labeled radiopharmaceuticals. The development of these radiopharmaceuticals can be made favorable by using appropriate buffer, incubation period, optimal pH, specific activity and reaction temperature. In this review, we have discussed the preparation of range of ⁹⁰Y transporting biological molecules such as antibodies radiolabeled peptides, antigens and microsphere with their clinical applications.     

Super face d-antimagic labeling for disjoint union of toroidal fullerenes

The discovery of the fullerene molecules and related forms of carbon such as nanotubes has generated an explosion of activity in chemistry, physics, and materials science. Classical fullerene is an all-carbon molecule in which the atoms are arranged on a pseudospherical framework made up entirely of pentagons and hexagons. A toroidal fullerene (toroidal polyhex) is a cubic bipartite graph embedded on the torus such that each face is a hexagon. In this paper we examine the existence of entire labeling, where face-weights of all 6-sided faces of disjoint union of toroidal fullerenes form an arithmetic progression with common difference \(\hbox {d}\in \{1,2,3\}\).     

Characterization of dipeptidylcarboxypeptidase of <Emphasis Type="Italic">Leishmania donovani</Emphasis>: a molecular model for structure based design of antileishmanials

Leishmania donovani dipeptidylcarboxypeptidsae (LdDCP), an angiotensin converting enzyme (ACE) related metallopeptidase has been identified and characterized as a putative drug target for antileishmanial chemotherapy. The kinetic parameters for LdDCP with substrate, Hip-His-Leu were determined as, Km, 4 mM and Vmax, 1.173 μmole/ml/min. Inhibition studies revealed that known ACE inhibitors (captopril and bradykinin potentiating peptide; BPP1) were weak inhibitors for LdDCP as compared to human testicular ACE (htACE) with Ki values of 35.8 nM and 3.9 μM, respectively. Three dimensional model of LdDCP was generated based on crystal structure of Escherichia coli DCP (EcDCP) by means of comparative modeling and assessed using PROSAII, PROCHECK and WHATIF. Captopril docking with htACE, LdDCP and EcDCP and analysis of molecular electrostatic potentials (MEP) suggested that the active site domain of three enzymes has several minor but potentially important structural differences. These differences could be exploited for designing selective inhibitor of LdDCP thereby antileishmanial compounds either by denovo drug design or virtual screening of small molecule databases.     

Two New Disulfated Triterpenoids from Zygophyllum fabago

From the aerial parts of Zygophyllum fabago, two new monosodium salts of sulfated derivatives of ursolic acid, along with two known quinovic acid glycosides were isolated. The structures of the new compounds were determined as (3β,4α)‐3,23,30‐trihydroxyurs‐20‐en‐28‐al 3,23‐di(sulfate) sodium salt (1 : 1) ( 1 ) and of (3β,4α)‐3,23,28‐trihydroxyurs‐20‐en‐30‐yl β‐D ‐glucopyranoside 3,23‐di(sulfate) sodium salt (1 : 1) ( 2 ) with the molecular formula C₃₀H₄₇NaO₁₀S₂ and C₃₆H₅₉NaO₁₅S₂, respectively. The structures of the known compounds were 3‐O‐(2‐O‐sulfo‐β‐D ‐quinovopyranosyl)quinovic acid 28‐β‐D ‐glucopyranosyl ester ( 3 ) and 3‐O‐(β‐D ‐glucopyranosyl)quinovic acid 28‐β‐D ‐glucopyranosyl ester ( 4 ) (quinovic acid=(3β)‐3‐hydroxyurs‐12‐ene‐27,28‐dioic acid). The structures of all these compounds were determined by using 1D‐ and 2D‐NMR spectroscopic techniques.     

Synthesis of 5‐(Arylselanyl)‐2‐(arylsulfanyl)benzoates by [3+3] Cyclocondensation of 3‐(Arylsulfanyl)‐1‐(silyloxy)buta‐1,3‐dienes with 2‐(Arylselanyl)‐3‐(silyloxy)alk‐2‐en‐1‐ones

Functionalized 5‐(arylselanyl)‐2‐(arylsulfanyl)benzoates were prepared by [3+3] cyclocondensation of 3‐(arylsulfanyl)‐1‐(silyloxy)buta‐1,3‐dienes with 2‐(arylselanyl)‐3‐(silyloxy)‐alk‐2‐en‐1‐ones.     

PAPER—Accelerating parallel evaluations of ROCS

Modern graphics processing units (GPUs) are flexibly programmable and have peak computational throughput significantly faster than conventional CPUs. Herein, we describe the design and implementation of PAPER, an open‐source implementation of Gaussian molecular shape overlay for NVIDIA GPUs. We demonstrate one to two order‐of‐magnitude speedups on high‐end commodity GPU hardware relative to a reference CPU implementation of the shape overlay algorithm and speedups of over one order of magnitude relative to the commercial OpenEye ROCS package. In addition, we describe errors incurred by approximations used in common implementations of the algorithm. © 2009 Wiley Periodicals, Inc. J Comput Chem 2010     

The effect of gamma irradiation on glass transition temperature and thermal stability of Se96Sn4 chalcogenide glass

Se₉₆Sn₄ chalcogenide glass was prepared by melt quenching technique and exposed, at room temperature, to different doses of 4, 8, 12, 24 and 33 kGy of high-energy ⁶⁰Co gamma irradiation. Differential scanning calorimeter (DSC) was used under non-isothermal condition to determine the glass transition temperature T_g, onset T_c and peak T_p temperatures of crystallization, of un-irradiated and γ-irradiated samples, at four different heating rates. The variation of T_g with heating rates was utilized to calculate the glass transition activation energy E_t for un-irradiated and γ-irradiated glass, using the methods suggested by Kissinger and Moynihan. Based on the obtained values of the characteristic temperatures T_g, T_c and T_p, thermal stability was monitored through the calculation of the S parameter and the crystallization rate factor 〈K_p〉 for irradiated and un-irradiated glass. Results reveal that, as γ-dose increases T_g increases up to 12 kGy then decreases at higher doses but remains more than that of un-irradiated glass. Meanwhile, both E_t and 〈K_p〉 attain their minimum values at the same dose of 12 kGy and the glass is thermally stable at this particular dose.