Characterization,Analysis, and Application of Fabricated Fe3O4-Chitosan-Pectinase Nanobiocatalyst

The investigation on fabrication of Fe₃O₄-chitosan-pectinase nanobiocatalyst was performed by covalently binding the pectinase onto carboxyl group activated chitosan-coated magnetic nanoparticles (CMNPs). The morphological and size distribution analysis of the different magnetic nanoparticles (MNPs) was done using transmission electron microscopy (TEM), and the average diameter was 11.07?±?3.04, 11.55?±?3.16, and 11.59?±?3.16 nm for MNPs, CMNPs, and fabricated nanobiocatalyst, respectively, suggesting that there was no significant change in the size of MNPs after coating and binding. The characteristic peaks occurred at 2θ of 30.39, 35.43, 43.37, 57.22, and 62.9, and their corresponding indices 220, 311, 400, 520, and 441 for different MNPs from the X-ray diffraction (XRD) studies confirmed the presence of Fe₃O₄ with the spinel structure, and there was no phase change even after coating and binding. The various required characteristic absorption peaks (575, 585, 1,563, 1,614, 1,651, and 1,653 cm^?1) from Fourier transform infrared (FT-IR) spectroscopy confirmed the surface modifications and binding of pectinase onto the MNPs. At the weight ratio of about 19.8?×?10^?3 mg bound pectinase/mg activated CMNPs, the activity of fabricated nanobiocatalyst was found to be maximum. In order to monitor their improved activity, the pH, temperature, reusability, storage ability, and kinetic studies were established.     

Green's function approach to study the propagation of SH‐wave in piezoelectric layer influenced by a point source

Green's function technique serves as a powerful tool to find the particle displacements due to SH‐wave propagation in layer of a shape different from the space between two parallel planes. Therefore, the present paper undertook to study the propagation of SH‐wave in a transversely isotropic piezoelectric layer under the influence of a point source and overlying a heterogeneous substrate using Green's function technique. The coupled electromechanical field equations are solved with the aid of Green's function technique. Expression for displacements in both layer and substrate, scalar potential and finally the dispersion relation is obtained analytically for the case when wave propagates along the direction of layering. Numerical computations are carried out and demonstrated with the aid of graphs for six different piezoelectric materials namely PZT‐5H ceramics, Barium titanate (BaTiO₃) ceramics, Silicon dioxide (SiO₂) glass, Borosilicate glass, Cobalt Iron Oxide (CoFe₂O₄), and Aluminum Nitride (AlN). The effects of heterogeneity, piezoelectric and dielectric constants on the dispersion curve are highlighted. Moreover, comparative study is carried out taking the phase velocity for different piezoelectric materials on one hand and isotropic case on the other. Dispersion relation is reduced to well‐known classical Love wave equation with a view to illuminate the authenticity of problem. Copyright © 2017 John Wiley & Sons, Ltd.     

Traceability and Authentication of Manila Clams from North-Western Adriatic Lagoons Using C and N Stable Isotope Analysis

In the Adriatic lagoons of northern Italy, manila clam (Ruditapes philippinarum) farming provides important socio-economic returns and local clams should be registered with the Protected Designations of Origin scheme. Therefore, there is a need for the development of rapid, cost-effective tests to guarantee the origin of the product and to prevent potential fraud. In this work, an elemental analysis (EA) coupled with isotope ratio mass spectrometry (IRMS) was employed to identify the isotopic fingerprints of clams directly collected onsite in three Adriatic lagoons and bought at a local supermarket, where they exhibited certification. In particular, a multivariate analysis of C/N, δ¹³C and δ¹⁵N in manila clam tissues as well as δ¹³C in shells and Δ¹³C (calculated as δ¹³C_shell–δ¹³C_tissues) seems a promising approach for tracking the geographical origin of manila clams at the regional scale.     

Discovery of a Potent GLUT Inhibitor from a Library of Rapafucins by Using 3D Microarrays

Glucose transporters play an essential role in cancer cell proliferation and survival and have been pursued as promising cancer drug targets. Using microarrays of a library of new macrocycles known as rapafucins, which were inspired by the natural product rapamycin, we screened for new inhibitors of GLUT1. We identified multiple hits from the rapafucin 3D microarray and confirmed one hit as a bona fide GLUT1 ligand, which we named rapaglutin A (RgA). We demonstrate that RgA is a potent inhibitor of GLUT1 as well as GLUT3 and GLUT4, with an IC₅₀ value of low nanomolar for GLUT1. RgA was found to inhibit glucose uptake, leading to a decrease in cellular ATP synthesis, activation of AMP‐dependent kinase, inhibition of mTOR signaling, and induction of cell‐cycle arrest and apoptosis in cancer cells. Moreover, RgA was capable of inhibiting tumor xenografts in vivo without obvious side effects. RgA could thus be a new chemical tool to study GLUT function and a promising lead for developing anticancer drugs.     

Superconducting linear accelerator system for NSC

This paper reports the construction of a superconducting linear accelerator as a booster to the 15 UD Pelletron accelerator at Nuclear Science Centre, New Delhi. The LINAC will use superconducting niobium quarter wave resonators as the accelerating element. Construction of the linear accelerator has progressed sufficiently. Details of the entire accelerator system including the cryogenics facility, RF electronics development, facilities for fabricating niobium resonators indigenously, and present status of the project are presented.     

Propagation of SH-wave in a corrugated viscous sandy layer sandwiched between two elastic half-spaces

The present paper attempts to investigate the effect of sandiness, corrugated boundary surfaces, heterogeneity, and gravity on phase velocity and attenuation of SH-wave propagating in a viscous sandy layer with corrugated upper and lower boundary surfaces sandwiched between an upper heterogeneous elastic half-space and lower viscoelastic half-space under gravity. Heterogeneity associated with the upper half-space is due to exponentially varying density which is a function of depth; but the rigidity is constant. The closed form of dispersion relation is established and found to be in complex form. Real part and imaginary part of the dispersion relation correspond to dispersion curve and attenuation curve, respectively. One of the salient points of present study is the use of DEBYE asymptotic expansion to establish that the obtained dispersion relation is in well-agreement with the classical Love wave equation in isotropic case. The effect of presence and absence of corrugated boundary surfaces, measured by initial flatness parameter, on dispersion and attenuation curves have been meticulously examined. Moreover, the substantial effect of heterogeneity, sandiness, internal friction, and Biot’s gravity parameter on phase velocity and attenuation coefficient of SH-wave has been studied and demonstrated by means of graphical illustration and numerical computations.     

Characterization of stable and reactive metabolites of piperine formed on incubation with human liver microsomes

Black pepper, though commonly employed as a spice, has many medicinal properties. It consists of volatile oils, alkaloids, pungent resins, etc., of which piperine is a major constituent. Though safe at low doses, piperine causes alteration in the activity of drug metabolising enzymes and transporters at high dose and is known to precipitate liver toxicity. It has a potential to form reactive metabolite(s) (RM) owing to the presence of structural alerts, such as methylenedioxyphenyl (MDP), α, β‐unsaturated carbonyl group (Michael acceptor), and piperidine. The present study was designed to detect and characterize stable and RM(s) of piperine formed on in vitro incubation with human liver microsomes. The investigation of RMs was done with the aid of trapping agents, viz, glutathione (GSH) and N‐acetylcysteine (NAC). The samples were analysed by ultra‐high performance liquid chromatography coupled with high resolution mass spectrometry (UHPLC‐HRMS) using Thermo Scientific Q Exactive Plus Orbitrap. Full scan MS followed by data‐dependent MS² (Full MS‐ddMS²) mode was used to establish mass spectrometric fragmentation pathways of protonated piperine and its metabolites. In total, four stable metabolites and their isomers (M1a‐c, M2a‐b, M3a‐c, and M4a‐b) were detected. Their formation involved removal of carbon (3, M1a‐c), hydroxylation (2, M2a‐b), hydroxylation with hydrogenation (3, M3a‐c), and dehydrogenation (2, M4a‐b). Out of these metabolites, M1, M2, and M3 are reported earlier in the literature, but their isomers and two M4 variants are novel. In addition, six novel conjugates of RMs, including three GSH conjugates of m/z 579 and three NAC conjugates of m/z 435, were also observed.     

A highly selective and sensitive in vivo fluorosensor for zinc(II) without cytotoxicity

A highly selective and sensitive fluorescent Zn(2+) sensor, 2,6-bis(2-hydroxy-benzoic acid hydrazide)-4-methylphenol (1), was designed and synthesized. In aqueous THF (4 : 6 v/v) ligand 1 induces a 2 : 1 complex formation with respect to Zn(2+) at physiological pH. This probe features visible light excitation(390 nm) and emission (490 nm) profiles, excellent selectivity responses for Zn(2+)over other competing biological metal ions with K(d) < 1 pM(2), LOD < 1 ng L(-1) and about 680 fold enhancement in fluorescent intensity upon Zn(2+) binding. It also exhibits cell permeability and intracellular Zn(2+) sensing in A375 human melanoma cancer cell.     

Simultaneous determination of sulfamethoxazole and trimethoprim in microgram quantities from low plasma volume by liquid chromatography–tandem mass spectrometry

A highly sensitive, selective and high-throughput liquid chromatography–tandem mass spectrometry (LC–MS/MS) method for simultaneous quantification of sulfamethoxazole (SMZ) and trimethoprim (TMP) has been developed and validated using imipramine as an internal standard. The analytes were extracted from 50 µL human plasma using solid phase extraction (SPE) and separated on Thermo Hypersil Gold C18 (50 mm × 4.6 mm, 5 μm) column under isocratic conditions in a run time of 2.5 min. Detection was carried out by tandem mass spectrometer, interfaced with electro spray ionization and operating in positive ionization mode. The calibration curves were linear over the concentration range of 0.88–80 µg/mL for SMZ and 0.03–30 µg/mL for TMP. The intra- and inter-day accuracy and precision (% CV) evaluated at four quality control levels were within 93.5–105.0% and 1.3–7.2% respectively. The absolute recovery was greater than 81% for both the analytes at two concentration levels. Stability of SMZ and TMP was assessed under different storage conditions. The validated method was successfully applied for a bioavailability study in 12 healthy volunteers after oral administration of 800 mg of SMZ and 160 mg of TMP succinate tablet formulations under fasting condition.     

Manganese(IV) complex with a polydentate Schiff base ligand: synthesis,crystal structure,TDDFT calculation,electronic absorption and EPR spectral study

A six-coordinate Mn(IV) complex, [Mn(H₂L)₂] (1) [H₄L = 2-methoxy-6-(tris(hydroxymethyl)methyliminomethyl)phenol], was synthesized and characterized by elemental analysis, single-crystal X-ray crystallography, FTIR, UV–Vis electronic absorption, and EPR spectroscopy. The single-crystal structural determination reveals that the complex crystallizes in tetragonal space group P4₁2₁2 and the tridentate Schiff base ligands are arranged in mer configuration chelating manganese, which exhibits as slightly distorted octahedral coordination sphere with a N₂O₄ chromophore. Weak hydrogen bonding interactions of uncoordinated hydroxyl groups result in a 2-D supramolecular structure. The UV–Vis electronic absorption and IR spectral data of 1 have been compared with the results obtained by employing DFT and time-dependent density functional theory calculation using B3LYP, B3PW91, and MPW1PW91 functionals, with 6-31G (d-p) and LanL2MB basis sets. The results of these calculations are functional-dependent and, among those used, B3PW91 proved to better reproduce the experimental results.