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Shiv Nadar University

(SoNS) School of Natural Sciences

The improvement of the plasma illumination (PI) properties of a microplasma device due to the application of nanocrystalline diamond-decorated graphene nanoflakes (NCD-GNFs) as a cathode is investigated. The improved plasma illumination (PI) behavior is closely related to the enhanced field electron emission (FEE) properties of the NCD-GNFs. The NCD-GNFs possess better FEE characteristics with a low turn-on field of 9.36 V μm-1to induce the field emission, a high FEE current density of 2.57 mA cm-2and a large field enhancement factor of 2380. The plasma can be triggered at a low voltage of 380 V, attaining a large plasma current density of 3.8 mA cm-2at an applied voltage of 570 V. In addition, the NCD-GNF cathode shows enhanced lifetime stability of more than 21 min at an applied voltage of 430 V without showing any sign of degradation, whereas the bare GNFs can last only 4 min. The superior FEE and PI properties of the NCD-GNFs are ascribed to the unique combination of diamond and graphene. Transmission electron microscopic studies reveal that the NCD-GNFs contain nano-sized diamond films evenly decorated on the GNFs. Nanographitic phases in the grain boundaries of the diamond grains form electron transport networks that lead to improvement in the FEE characteristics of the NCD-GNFs. © 2016 The Royal Society of Chemistry.

World University root node

Physics

Fulltext

RSC Advances

Growth, structural and plasma illumination properties of nanocrystalline diamond-decorated graphene nanoflakes

Microwave processing of SrBi2Nb2O9 ferroelectric ceramics was targeted in the current work. In particular, Curie temperature, dielectric constant, dielectric loss and dc conductivity were studied for microwave sintered SrBi2Nb2O9 ferroelectric ceramics in the range 1050-1200 °C. The space charge dielectric relaxation was found noticeable in all sintered samples and electrical properties like dielectric constant, loss and dc conductivity were significantly affected due to this dielectric relaxation. An optimum processing condition was targeted by investigating frequency and temperature dependent dielectric responses along with dc conductivity. © 2016 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

Ceramics International

Microwave processed SrBi2Nb2O9 ferroelectric ceramics with controlled dielectric relaxation and metallic conduction

A library of arylidenefuropyridinediones was discovered as potent inhibitors of Leishmania donovani Topoisomerase 1 (LdTop1) where the active molecules displayed considerable inhibition with single digit micromolar EC 50 values. This molecular library was designed via intuitive scaffold hopping and bioisosteric modification of known topoisomerase 1 inhibitors such as camptothecin, edotecarin and etc. The design was rationalized by molecular docking analysis of the compound prototype with human topoisomerase 1 (HTop1) and Leishmania donovani topoisomerase 1(LdTop1). The most active compound 4 displayed no cytotoxicity against normal mammalian COS7 cell line (∼100 fold less inhibition at the EC 50). Similar to camptothecin, 4 interacted with free LdTop1 as observed in the preincubation DNA relaxation inhibition experiment. It also displayed anti-protozoal activity against Leishmania donovani promastigote. Crystal structure investigation of 4 and its molecular modelling with LdTop1 revealed putative binding sites in the enzyme that could be harnessed to generate molecules with better potency.

Chemistry

Scientific Reports

Identification of Leishmania donovani Topoisomerase 1 inhibitors via intuitive scaffold hopping and bioisosteric modification of known Top 1 inhibitors

The variation of electron density in TiO2-x nanochannels, exhibiting resistive switching phenomenon, produced by Ar+ ion-irradiation at the threshold fluence of 5 × 1016 ions/cm2 is demonstrated by X-ray reflectivity (XRR). The transmission electron microscopy reveals the formation of nanochannels, while the energy dispersive X-ray spectroscopy confirms Ti enrichment near the surface due to ion-irradiation, in consistent with the increase in electron density by XRR measurements. Such a variation in Ti concentration indicates the evolution of oxygen vacancies (OVs) along the TiO2-x nanochannels, and thus paves the way to explain the operation and performance of the Pt/TiO2-x/Pt-based memory devices via OV migration. © 2016 Author(s).

Applied Physics Letters

Probing electron density across Ar+ irradiation-induced self-organized TiO2- x nanochannels for memory application

We have demonstrated a facile synthesis of diversely substituted quinazolines and 3,4-dihydroquinazolines through the o-iodoxybenzoic acid (IBX) mediated tandem reaction of readily available o-aminobenzylamine and aldehydes. The yield of the reactions generally ranged from 70\% to 95\%. This mild protocol provides an efficient strategy toward the synthesis of these classes of heterocycles. © Georg Thieme Verlag Stuttgart.

Synthesis (Germany)

Synthesis of Quinazolines and Dihydroquinazolines: o-Iodoxybenzoic Acid Mediated Tandem Reaction of o-Aminobenzylamine with Aldehydes

Mathematics

Physics of Life Reviews

Predicting spatial dynamics of infectious disease: Causes and consequences: Comment on “Pattern transitions in spatial epidemics: Mechanisms and emergent properties” by Gui-Quan Sun et al.

Benzoxazine resins, although exhibiting attractive properties; particularly high thermal stability and near zero- shrinkage, suffer from a major drawback associated with its high curing temperature. In view of the Lewis acidity associated with the Zn4O nodes in a zinc based metal organic framework [Zn4O(BDC)3, MOF5], we considered it of interest to explore its potential as a curing accelerator for a representative biobased benzoxazine resin. MOF 5 was solvothermally synthesized and characterized using different techniques including powder X-ray diffraction (PXRD), Scanning Electron Microscopy (SEM), Thermogravimetric Analysis (TGA), Fourier transform infrared spectroscopy (FT-IR) and Nitrogen physisorption measurements. Bio-based benzoxazine resin was synthesized by mannich type condensation of cardanol and aniline with formaldehyde under solventless conditions, the structure of which was confirmed using FT-IR and 1H-NMR. The curing behavior of the synthesized resin was systematically investigated using non-isothermal Differential Scanning Calorimetry (DSC). Introduction of MOF 5 led to a shift in the curing profile to lower temperature, the extent of which was proportional to the amount of MOF 5 in the formulation. DSC studies were performed at different heating rates to establish the kinetic parameters associated with the curing of the resin. Activation energy, as calculated using Kissinger Akahira Sunose method, was found to concomitantly decrease from 98 kJ/mol to 58 kJ/mol upon addition of MOF 5 (5 \% w/w). © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

ChemistrySelect

Metal-Organic Frameworks as curing accelerators for benzoxazines

Early detection of gastric cancers saves lives, but remains a diagnostic challenge. In this study, we aimed to identify cell-surface biomarkers of early gastric cancer. We hypothesized that a subset of plasma membrane proteins induced by the Helicobacter pylori oncoprotein CagA will be retained in early gastric cancers through non-oncogene addiction. An inducible system for expression of CagA was used to identify differentially upregulated membrane protein transcripts in vitro. The top hits were then analyzed in gene expression datasets comparing transcriptome of gastric cancer with normal tissue, to focus on markers retained in cancer. Among the transcripts enriched upon CagA induction in vitro, a significant elevation of CEACAM6 was noted in gene expression datasets of gastric cancer. We used quantitative digital immunohistochemistry to measure CEACAM6 protein levels in tissue microarrays of gastric cancer. We demonstrate an increase in CEACAM6 in early gastric cancers, when compared to matched normal tissue, with an AUC of 0.83 for diagnostic validity. Finally, we show that a fluorescently conjugated CEACAM6 antibody binds avidly to freshly resected gastric cancer xenograft samples and can be detected by endoscopy in real time. Together, these results suggest that CEACAM6 upregulation is a cell surface response to H. pylori CagA, and is retained in early gastric cancers. They highlight a novel link between CEACAM6 expression and CagA in gastric cancer, and suggest CEACAM6 to be a promising biomarker to aid with the fluorescent endoscopic diagnosis of early neoplastic lesions in the stomach.

Oncotarget

CEACAM6 is upregulated by Helicobacter pylori CagA and is a biomarker for early gastric cancer

A diradical approach to obtain stable organic dyes with intense absorption around λ=1100 nm is reported. The para- and meta-quinodimethane-bridged BODIPY dimers BD-1 and BD-2 were synthesized and were found to have a small amount of diradical character. These molecules exhibited very intense absorption at λ=1088 nm (ε=6.65×105 M-1 cm-1) and 1136 nm (ε=6.44×105 M-1 cm-1), respectively, together with large two-photon-absorption cross-sections. Structural isomerization induced little variation in their diradical character but distinctive differences in their physical properties. Moreover, the compounds showed a selective fluorescence turn-on response in the presence of the hydroxyl radical but not with other reactive oxygen species. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA.

Angewandte Chemie - International Edition

A Diradical Approach towards BODIPY-Based Dyes with Intense Near-Infrared Absorption around λ=1100 nm

The crystal structure of a ternary sulfide with the approximate composition LiCuS, which is a promising candidate for environment-friendly battery and solar cell materials is reported. The crystal structure was solved by a combination of neutron and X-ray powder diffraction data and 7 Li solid-state NMR analysis. A yellow powder, Li1.1Cu0.9S, was obtained by the reaction of CuS with a slight excess of Li metal. The compound crystallizes in the Na3AgO2 structure type in the space group Ibam. An idealized crystal structure of Li1.1Cu0.9S can be derived from the cubic Li2S structure by moving a part of the Li along the c axis so that these Li atoms become linearly coordinated by S. All the metal sites are occupied by randomly mixed Li and Cu atoms; however, there is a strong preference for linear coordination by Cu. The density functional theory calculations show that Li1.1Cu0.9S is a direct band-gap semiconductor with an energy gap of 1.95 eV in agreement with experimental data.

Solid State Sciences

LiCuS, an intermediate phase in the electrochemical conversion reaction of CuS with Li: A potential environment-friendly battery and solar cell material