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Shiv Nadar University

(SoNS) School of Natural Sciences

The efficacy of 50 keV Ar+-ion irradiation toward the interfacial and stoichiometric engineering of strained Al-doped ZnO (AZO)/TiO2 heterostructure is systematically investigated using a variety of experimental techniques, notably by cross-sectional transmission electron microscopy. Glancing-angle X-ray diffraction evidences the release of in-plane compressive stress from the as-grown AZO/TiO2 bilayer structure at a critical fluence of 1 × 1016 ions/cm2, and we discuss in the light of microcracks and voids formation combined with the dewetting phenomenon. Ion irradiation also leads to an improvement of stoichiometry in both top AZO and underneath amorphous TiO2 layers, as manifested by depth-dependent energy dispersive X-ray spectroscopy owing to the large diffusion of oxygen toward the AZO/TiO2 interfacial region through the AZO defect sites. Such ion beam induced self-healing in stoichiometry of AZO/TiO2 heterostructure has been attributed to a conjunction of sputtering and diffusion phenomena involving the constituent elements (Zn, Ti, and O). Further increase in ion fluence up to 5 × 1016 ions/cm2 causes a complete deterioration of the heterostructure with the formation of a graded layer via intermixing of these elements, followed by the evolution of voids. © 2018 Author(s).

Physics

Fulltext

Journal of Applied Physics

Probing the impact of energetic argon ions on the structural properties of ZnO:Al/TiO2 heterostructures

The flexibility of amorphous anodized alumina (AAO) in developing radiation dosimeter for hadron therapy is reported by controlled carbon ion implantation, followed by thermoluminescence (TL) measurements. The efficacy of amorphous AAO in controlling TL sensitivity is found to be governed by an increase in F+ defect centers as a function of carbon concentration, as revealed from the close resemblance of the trend in photoluminescence intensity. Moreover, its nanoporous structure is demonstrated to be advantageous for defect engineering due to the increase in the surface-to-volume ratio. Detailed X-ray photoelectron spectroscopy analysis suggests the formation of F+ centers by substituting Al3+ ions with C2+ in the vicinity of oxygen vacancies, where depth-dependent study showed the evolution of conducting channels owing to sp2 hybridized C-C bonding, leading to a differential charging effect. This work provides a direction to tune nanoporous AAO in its amorphous form for future ion beam dosimetry. © 2018 Author(s).

Carbon doping controlled thermoluminescent defect centers in nanoporous alumina for ion beam dosimetry

First layer Aurivillius Bismuth Molybdate Tungstate ceramic [Bi2Mo1−xWxO6 (BMoW); x = 0.00, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.08 and 0.10] compositions are prepared using deep penetrating microwave sintering in air. All samples show known perovskite phase formation just after 5 h calcinations at 575 °C. X-ray diffraction and transmission electron microscopy based energy dispersive spectroscopy are used to confirm the phase-purity and gross elemental concentration change besides particle size. Nearly doubleε′-values are obtained for investigated BMoW materials compared to earlier reported values. Silver percolation through electrodes in bismuth oxide deficient surfaces of BMoW ceramic powders induces radio wave absorption in the frequency range 2 to 4 MHz. Characteristic third phase transition (γ→ γ″ ′) of Bi2MoO6 material dissolves gradually on increasing tungsten concentration. The introduction of tungsten in BMo matrix increases the dipolar strength of MoO6 octahedrons bending against infrared absorption as evidenced from FTIR analysis. Additionally appearing FTIR peaks provide a strong indication of CO and CO2 contamination on exposed powder surfaces useful for photocatalytic applications. © 2018, Springer Science+Business Media, LLC, part of Springer Nature.

World University root node

Journal of Materials Science: Materials in Electronics

Integrating third phase transition and CO/CO2 contamination in microwave tailored Bi2Mo1−xWxO6 nano materials

A simple oxidative ring rearrangement of diversely substituted 1-(2-amminoaryl)-tetrahydro-β-carbolines has been developed to generate architecturally interesting tetrahydro-1H-indolo[2,3-b]pyrrolo[3,2-c]quinolones. This unique transformation involves four reaction centers (aniline, C1-carboline and C2/C3 of indole) and utilizes tert-butylhypochlorite as the reagent. The generic nature of the reaction was demonstrated by the synthesis of a wide variety of analogs 9a-j. A putative reaction mechanism was proposed. Cytotoxicity screening of these compounds against three human cancer cells (A2780 ovarian and HCT116 colorectal carcinoma cell lines and A549 lung adenocarcinoma cell line) revealed selective inhibition of proliferation of the A2780 human ovarian carcinoma cell line by one of the molecules 9a with an IC50 of 14 μM. No cytotoxic activity was observed in human normal fibroblasts for concentrations up to 100 μM. Compound 9a induced hyperpolarization of the mitochondrial membrane potential of the A2780 cell line leading to an increase of reactive oxygen species (ROS) that trigger cell death via apoptosis. Interestingly, compound 9a was also able to induce cell death via autophagy. Compounds that induce apoptosis and autophagy, thus leading to cancer cells' death, are good candidates for cancer therapy. © 2018 The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.

Chemistry

New Journal of Chemistry

Synthesis of tetrahydro-1: H -indolo[2,3- b] pyrrolo[3,2- c] quinolones via intramolecular oxidative ring rearrangement of tetrahydro-β-carbolines and their biological evaluation

Indole derivatives bearing C-2 substituents have garnered a lot of attention due to their diverse biological activities. Various methods forthe synthesis of these compounds have been reported. Inspired by the hydrolysis of imines, an oxidative ring-opening reaction of 1-aryltetrahydro-β-carbolines with catalytic iodine in aqueous hydrogen peroxide, and also in the presence of appropriate amines, is described for the generation of 2-aroyl and arylmethanimine indole derivatives. The reaction proceeds under mild reaction conditions with ethanol as the solvent or under solvent-free conditions, respectively. This metal-free strategy facilitates the formation of the desired substituted C-2 indoles in moderate to excellent yields. The utility of this reaction is demonstrated by a facile multigram-scale synthesis of Luzindole, a selective melatonin receptor antagonist and an investigational drug against depression and disruption of the circadian rhythm. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

European Journal of Organic Chemistry

Iodine-Catalyzed Metal-Free Oxidative Ring Opening of 1-Aryltetrahydro-β-carbolines: Facile Synthesis of C-2 Aroyl and Aryl Methanimino Indole Derivatives

We investigate a new realization of extended quantum-mechanical supersymmetry. We first show that an N = 2 quantum-mechanical supersymmetry is hidden in the four-dimensional (4D) spectrum of the KaluzaKlein decomposition for the higher dimensional Dirac field, that is, KaluzaKlein mode functions of 4D right-handed spinors and 4D left-handed ones form N = 2 supermultiplets. In addition to N = 2 supersymmetry, we discover that an N-extended supersymmetry (N = d + 2 (d + 1) for d = even (odd) extra dimensions) is further hidden in the 4D spectrum. The extended symmetry can explain additional degeneracy of the spectrum. Furthermore, we show that a superpotential can be introduced into the N-extended supercharges and clarify the condition to preserve the supersymmetry. The partial breaking of the supersymmetry is also demonstrated. © 2018 IOP Publishing Ltd Printed in the UK.

Journal of Physics A: Mathematical and Theoretical

Extended supersymmetry in Dirac action with extra dimensions

We address the presently reported significant flavor anomalies in the K and B meson systems such as the CP violating Kaon decay (ε′/ε) and lepton-flavor universality violation in B meson decays (RK(∗), and also commenting RD(∗)), by proposing flavorful and chiral vector bosons as the new physics constitution at ∼ 1TeV. Interestingly, if the new (composite) vector bosons are quite heavier than ∼ 1TeV, we face a difficulty in addressing the anomaly in ε′/ε consistently with the constraint from the K0-K0 mixing. Both of the anomalies can be addressed within 1σ confidence levels individually, where the relevant parameter space will be investigated by the NA62 and KOTO experiments, in addition to direct searches at the large hadron collider. © Copyright owned by the author(s) under the terms of the Creative Commons.

Proceedings of Science

Simultaneous explanation of K and B anomalies in vectorlike compositeness

In this paper, we introduce the notion of generalized positive subdefinite matrices of level k by generalizing the definition of generalized positive subdefinite matrices introduced by Crouzeix and Komlósi in [Applied optimization. Vol. 59, Dordrecht: Kluwer Academic Publications; 2001. p. 45–63]. The main motivation behind this generalization is to identify new subclasses of row sufficient matrices [Cottle, Pang and Venkateswaran, Linear Algebra Appl. 1989;114/115:231–249] which are not a subclass of copositive matrices. We establish new sufficient conditions for a matrix to be a non-copositive P0 matrix and a non-copositive row sufficient matrix using the notion of generalized positive subdefinite matrices of level k. We present a new termination result for Lemke’s algorithm which supplements Jones’ result [Math Program. 1986;35:239–242]. © 2017, © 2017 Informa UK Limited, trading as Taylor & Francis Group.

Mathematics

Linear and Multilinear Algebra

On generalizations of positive subdefinite matrices and the linear complementarity problem

Purpose: To determine the prevalence and incidence of epilepsy in an onchocerciasis endemic region of South Sudan. Methods: In May 2018, a door-to-door household survey was conducted in 8 study sites in an onchocerciasis endemic area in Maridi County. Results: A total of 2511 households agreed to participate in the study, corresponding to 17,652 individuals. An epilepsy screening questionnaire identified 799 persons suspected to have epilepsy (4.5\%); in 736 of the 766 persons (96.1\%) seen by a clinical officer the diagnosis of epilepsy was confirmed. Adding 38 persons who were not seen but with a positive answer to a combination of screening questions, 774 persons (4.4\%) had epilepsy. Epilepsy prevalence was highest in the 11–20 age group (10.5\%); 66 persons with epilepsy (PWE) developed their first seizures in the year preceding the survey (annual incidence = 373.9/100.000). Neurocysticercosis cannot explain the high epilepsy prevalence since no pigs are kept in the area. Independent risk factors for epilepsy included male gender, belonging to a “permanent household” and a farming family, and living in a village bordering the Maridi River. Only 7209 (40.8\%) of the population took ivermectin in 2017. Conclusion: A very high prevalence and incidence of epilepsy was observed in several villages in Maridi County located close to the Maridi River and the Maridi dam. Urgent action is needed to prevent children in Maridi County from developing OAE by strengthening the onchocerciasis elimination program. © 2018 The Authors

Seizure

High prevalence of onchocerciasis-associated epilepsy in villages in Maridi County, Republic of South Sudan: A community-based survey

The probability that all eigenvalues of a product of m independent N× N subblocks of a Haar distributed random real orthogonal matrix of size (Li+ N) × (Li+ N) , (i= 1 , ⋯ , m) are real is calculated as a multidimensional integral, and as a determinant. Both involve Meijer G-functions. Evaluation formulae of the latter, based on a recursive scheme, allow it to be proved that for any m and with each Li even the probability is a rational number. The formulae furthermore provide for explicit computation in small order cases. © 2017, Springer Science+Business Media New York.