Department of Chemistry

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We analyse robustness of nonlocal correlation in multiqubit entangled states—three- and four-qubit GHZ class and three-qubit W class—useful for quantum information and computation, under noisy conditions and weak measurements. For this, we use a Bell-type inequality whose violation is considered as a signature for confirming the presence of genuine nonlocal correlations between the qubits. In order to demonstrate the effects of noise and weak measurements, an analytical relation is established between the maximum expectation value of three and four-qubit Svetlichny operators for the systems under study, noise parameter and strengths of weak measurements. Our results show that for a set of three- and four-qubit GHZ class states, maximal nonlocality does not coincide with maximum entanglement for a given noise parameter and a certain range of weak measurement parameter. Our analysis further shows an excellent agreement between the analytical and numerical results. © 2018, Springer Science+Business Media, LLC, part of Springer Nature.

World University root node

Quantum Information Processing

Analysing nonlocality robustness in multiqubit systems under noisy conditions and weak measurements

Serum Albumin is a major carrier protein and its binding with drugs is important to examine the change in pharmacokinetic properties due to interaction amongst drugs. In the present study we have attempted to understand the relevant drug-drug interaction (DDI) between two common drugs viz, paracetamol, an anti-inflammatory and fluorouracil, an anti-cancer drug. In-vitro spectroscopic methods viz., fluorescence quenching and UV-vis absorption have been employed for the drug-bovine serum albumin (BSA) complexes studies. The binding parameters and quenching constants have been determined for BSA-Paracetamol and BSA-5Fluorouracil complex according to literature models. It is also predicted from the quenching studies that BSA-5Fluorouracil is a stronger complex than BSA-Paracetamol. On the other hand paracetamol can alter binding affinity of 5Fluorouracil towards BSA. Hence it becomes clear that although the drugs could be administered simultaneously but they influence each other's binding with protein in a concentration dependent fashion. Further these results also indicate that availability of free 5Fluorouracil in blood may increase in presence of paracetamol. © 2018 Author(s).

AIP Conference Proceedings

The effect of paracetamol on 5 fluorouracil and bovine serum albumin interaction: A biophysical study

Despite relatively high manufacturing cost, crystalline-Si solar cell continues to hold promising future due to its high energy conversion efficiency and long life. As regards cost, one pertinent issue is the top electrode metallization of textured cell surface, which typically involves screen printing of silver paste. The associated disadvantages call for alternative methods that can lower the cost without compromising the solar cell efficiency. In the present work, a highly interconnected one-dimensional (1D) metal wire network has been employed as front electrode on conventional Si wafers. Here, for the first time, we report an innovative solution based crackle templating method for conformal metal wire network patterning over large textured surfaces. Laser beam induced current mapping showed uniform photocurrent collection by the electrodes without any shadow losses. With electroless deposition of Ni wire network on corrugated solar cell, a short circuit current of 33.28 mA/cm2 was obtained in comparison to 20.53 mA/cm2 without the network electrode. On comparing the efficiency with the conventional cells with screen printed electrodes, a 20% increment in efficiency has been observed. Importantly, the estimated manufacturing cost is at least two orders lower. © 2017 American Chemical Society.

ACS Applied Materials and Interfaces

Highly Conformal Ni Micromesh as a Current Collecting Front Electrode for Reduced Cost Si Solar Cell

Understanding the regulatory factors of self-assembly processes is a necessity in order to modulate the nano-structures and their properties. Here, the self-assembly mechanism of a peptide-perylenediimide (P-1) conjugate in mixed solvent systems of THF/water is studied and the semiconducting properties are correlated with the morphology. In THF, right handed helical fibers are formed while in 10% THF-water, the morphology changes to nano-rings along with a switch in the helicity to left-handed orientation. Experimental results combined with DFT calculations reveal the critical role of thermodynamic and kinetic factors to control these differential self-assembly processes. In THF, P-1 forms right handed helical fibers in a kinetically controlled fashion. In case of 10% THF-water, the initial nucleation of the aggregate is controlled kinetically. Due to differential solubility of the molecule in these two solvents, elongation of the nuclei into fibers is restricted after a critical length leading to the formation of nano-rings which is governed by the thermodynamics. The helical fibers show superior semi-conducting property to the nano-rings as confirmed by conducting-AFM and conventional I-V characteristics. © 2017 The Author(s).

Department of Computer Science & Engineering

Fulltext

Scientific Reports

Solvent Assisted Tuning of Morphology of a Peptide-Perylenediimide Conjugate: Helical Fibers to Nano-Rings and their Differential Semiconductivity

The present study describes non-covalent interaction and complexation behaviour of sodium ascorbate (SA) with cucurbit[6]uril (CB[6]) at neutral pH in aqueous Na2SO4 solution. The interaction behaviour is investigated using various analytical techniques like NMR, UV–Vis, fluorescence, TGA and DRS. The substantial increase in the intensity of emission and absorption spectra of sodium ascorbate is observed. The Benesi–Hildebrand evaluation method is used to determine the stoichiometry and equilibrium constant of the cucurbit[6]uril–sodium ascorbate complex, which suggested the 1:1 complex. Time-dependent 1H NMR, 13C CP MAS and CD studies also echoed non-covalent interaction between SA with CB[6]. © 2016 Informa UK Limited, trading as Taylor & Francis Group.

Supramolecular Chemistry

Understanding behaviour of vitamin-C guest binding with the cucurbit[6]uril host

Agile nanostructure architectures and smart combinations of semiconducting metal oxide materials are key features of high-performing dye-sensitized solar cells (DSSCs). Herein, we synthesize mesoporous solid nanospheres of ZnO–TiO2 with type-II heterojunction and use these as an efficient photoanode material for excellent photoconversion. These polydisperse aggregates doped with 1 %, 5 %, and 10 % of ZnO exhibit improved solar cell performance with respect to pristine TiO2 under AM 1.5 G. The 1 % ZnO doped TiO2 nanosphere possess high specific surface area (84.23 m2 g−1) as a photoanode and shows high photoconversion efficiency of about 8.07 % with ca. 18 % improvement in the photocurrent density (Jsc) compare to TiO2 nanosphere. The improved solar cell performance (Δη=40 %) of ZnO decorated TiO2 nanospheres is ascribed to type-II heterojunction of ZnO–TiO2, that reduces the electron recombination and synergistically enhances the electron mobility and charge collection capability. © 2017 Wiley-VCH Verlag GmbH &amp; Co. KGaA, Weinheim

Energy Technology

Zinc Oxide–Titania Heterojunction-based Solid Nanospheres as Photoanodes for Electron-Trapping in Dye-Sensitized Solar Cells

Analysis of the interaction of pesticides and their metabolites with the cellular proteins has drawn considerable attention in past several years to understand the effect of pesticides on environment and mankind. In this study, we have investigated the binding interaction of Bovine Serum Albumin (BSA) with a widely used organophosphorous insecticide chlorpyrifos (CPF), and its stable metabolite, 3,5,6-trichloro-2-pyridinol (TCPy) to provide a comparative analysis of the two molecules by employing various spectroscopic techniques viz., UV–vis absorption, Circular Dichroism (CD), and Fluorescence spectroscopy. The fluorescence quenching studies of BSA emission in two different solvents viz., water and methanol in presence of CPF and TCPy have led to the revelation of several interesting facts about the pesticide-protein interaction. It has been found that both the molecules cause static quenching of BSA emission as seen from the Stern-Volmer constant (Ksv) irrespective of the solvent used for the analysis. While TCPy is a stronger quencher in water, it exhibits comparable quenching capacity with CPF in methanol. The solvent dependent differential binding interaction of the two molecules finally indicates possibility of diverse bio-distribution of the pesticides within human body. The UV–vis and CD spectra of BSA in presence of the test molecules have unravelled that the molecules formed ground state complex that are highly reversible in nature and have minimal effect on the protein secondary structure. Furthermore it is also understood that structural changes of BSA in presence of CPF is significantly higher compared to that in presence of TCPY. © 2017 Elsevier Inc.

Pesticide Biochemistry and Physiology

Solvent-dependent binding interactions of the organophosphate pesticide, chlorpyrifos (CPF), and its metabolite, 3,5,6-trichloro-2-pyridinol (TCPy), with Bovine Serum Albumin (BSA): A comparative fluorescence quenching analysis

Representing graphs as quantum states is becoming an increasingly important approach to study entanglement of mixed states, alternate to the standard linear algebraic density matrix-based approach of study. In this paper, we propose a general weighted directed graph framework for investigating properties of a large class of quantum states which are defined by three types of Laplacian matrices associated with such graphs. We generalize the standard framework of defining density matrices from simple connected graphs to density matrices using both combinatorial and signless Laplacian matrices associated with weighted directed graphs with complex edge weights and with/without self-loops. We also introduce a new notion of Laplacian matrix, which we call signed Laplacian matrix associated with such graphs. We produce necessary and/or sufficient conditions for such graphs to correspond to pure and mixed quantum states. Using these criteria, we finally determine the graphs whose corresponding density matrices represent entangled pure states which are well known and important for quantum computation applications. We observe that all these entangled pure states share a common combinatorial structure. © 2017, Springer Science+Business Media New York.

Department of Physics

Laplacian matrices of weighted digraphs represented as quantum states

We report temperature dependent electron paramagnetic resonance (EPR) studies on polycrystalline YCrO3 samples at X-band (9.46 GHz) in the temperature range of 120 K-298 K. The EPR spectra exhibit a single broad line across the whole temperature range, attributed to Cr3+ ions. The variation of EPR spectra parameters (line width, integrated intensity, and g-factor) as a function of temperature was analyzed to understand the nature of spin-dynamics in the paramagnetic region of YCrO3. A peak in the g-factor suggests the presence of a new phase within the paramagnetic state at an intermediate point of temperature T IP ∼ 230 K, attributed to the onset of short range canted antiferromagnetic correlations in the material much above 140 K, Néel temperature (T N) of YCrO3. The EPR intensity increases with a decrease in temperature up to T N due to the renormalization of the magnetic moments arising from the appearance of canted antiferromagnetic correlations. Further, temperature dependent dielectric measurements also exhibit an anomaly at ∼230 K suggesting the presence of magnetodielectric coupling in YCrO3, with a possibility towards a relatively high temperature magnetodielectric system. © 2017 IOP Publishing Ltd.

Journal of Physics Condensed Matter

Temperature dependent electron paramagnetic resonance study on magnetoelectric YCrO3

The K-Ras GTPase is a major target in anticancer drug discovery. However, direct interference with signaling by K-Ras has not led to clinically useful drugs yet. Correct localization and signaling by farnesylated K-Ras is regulated by the prenyl binding protein PDEδ. Interfering with binding of PDEδ to K-Ras by means of small molecules provides a novel opportunity to suppress oncogenic signaling. Here we describe the identification and structure-guided development of novel K-Ras–PDEδ inhibitor chemotypes based on pyrrolopyridazinones and pyrazolopyridazinones that bind to the farnesyl binding pocket of PDEδ with low nanomolar affinity. We delineate the structure–property relationship and in vivo pharmacokinetic (PK) and toxicokinetic (Tox) studies for pyrazolopyridazinone-based K-Ras–PDEδ inhibitors. These findings may inspire novel drug discovery efforts aimed at the development of drugs targeting oncogenic Ras. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.