Physics

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Shiv Nadar University

Unfortunately, in the original version of this article the updated Fig. 3 was not replaced. Please find below the updated Fig. 3. This has been corrected by publishing this correction article. The original article has been updated. (Figure presented.). © 2021, Springer Science+Business Media, LLC, part of Springer Nature.

World University root node

(SoNS) School of Natural Sciences

Fulltext

Journal of Materials Science: Materials in Electronics

Correction to: Annealing temperature-driven near-surface crystallization with improved luminescence in self‐patterned alumina films (Journal of Materials Science: Materials in Electronics, (2021), 32, 9, (11709-11718), 10.1007/s10854-021-05790-0)

The impact of annealing on luminescence properties of radio-frequency magnetron sputtering grown alumina films and their possible application in radiation measurement are presented. Here, grazing incidence X-ray diffraction study reveals the growth of amorphous alumina films, while the annealing treatment results in the gradual formation of nanocrystallites. They are found to be embedded in the amorphous matrix by cross-sectional Transmission Electron Microscopy for 1200 °C annealed thin film. The evolution of self-patterned wrinkles has also been observed at the surface by Scanning Electron Microscopy. A comprehensive analysis of optically active defect centers is carried out by room temperature photoluminescence (PL) measurement. This indicates a monotonic increase of oxygen vacancies (F centers) with increasing annealing temperature up to 1200 °C, though they are not directly correlated with the thermoluminescence (TL) results after exposing them to gamma radiation from a 60Co source. Based on PL analysis, the TL glow curves with increasing annealing temperature are elucidated in the light of the involvement of both trap centers and F-type recombination centers residing at grain boundaries. In terms of TL results, 1200 °C annealed alumina film is found to be superior to both the as-grown film, and the one annealed at 1100 °C. Finally, the linear TL response curves in the 1200 °C annealed film after exposing to both gamma radiation (up to 5 kGy) and energetic charged particles (80 MeV carbon ions) are demonstrated up to 130 kGy. © 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.

Annealing temperature-driven near-surface crystallization with improved luminescence in self‐patterned alumina films

In present article, we have fabricated micro/nano hierarchical structured aluminium surfaces with a vivid range of wettability and controllable adhesion using a facile and environment-friendly approach. The micropatterned surfaces show hydrophobicity with high adhesion due to impregnated wetting state, analogous to rose petal effect. Interestingly, the micro/nano hierarchical structured surfaces become superhydrophilic due to formation of aluminium oxide and hydroxide nanoflakes. After fluorination, these surfaces become superhydrophobic with a very low contact angle hysteresis. They also exhibit a very high chemical and thermal stability along with excellent self-cleaning capability. © 2021 Elsevier B.V.

Mechanical Engineering

(SoE) School of Engineering

Materials Letters

Structured aluminium surfaces with tunable wettability fabricated by a green approach

Learning and associative memory are understood as emergent phenomena resulting from interactions between a complex network of neurons. It is well known that the structure of such a neural network heavily influences its function. Biological networks (e.g. neuronal network of the worm Caenorhabditis elegans) have been shown to exhibit small-world characteristics. To investigate the structure-function relationship in small-world networks, we simulate the Hopfield model of associative memory on a regular and Watts-Strogatz network. We obtain estimates of memory capacity on a regular and a WS network through numerical simulations. Further, we study how changing the probability of rewiring and local connectivity in a WS network affects the performance of associative memory. We find that the performance on small-world networks is as robust as that on random networks despite using only a fraction of connections, making the former biologically favorable. Our simulations are in agreement with experimental evidence found in the existing literature on small-world characteristics in biological networks and give deeper insights into this phenomenon. © 2021 Author(s).

AIP Conference Proceedings

Associative memory on small-world networks

The cellular membranes are composed of hundreds of components such as lipids, proteins, and sterols that are chemically and physically distinct from each other. The lipid–lipid and lipid–protein interactions form domains in this membrane, which play vital roles in membrane physiology. The hybrid lipids (HLs) with one saturated and one unsaturated chain can control the shape and size of these domains, ensuring the thermodynamic stability of a membrane. In this study, the thermodynamics of mixing of a HL and its structural effects on the phase separated domains in a model membrane composed of a saturated and an unsaturated lipid have been investigated. The HL is observed to mix into an unsaturated lipid reducing the Gibbs free energy, whereas the mixing is unfavorable in a saturated lipid. The presence of an HL in an unsaturated lipid tends to increase its area fraction, which is reflected in the enhanced correlation length across the bilayers in a multilayered sample. There is a feeble effect on the domain structure of the saturated lipid due to the presence of the HLs at the phase boundary. This study concludes that the HLs preferentially participate in the unsaturated lipid regions compared to that of a saturated lipid. © 2021 The Authors. Published by American Chemical Society

ACS Omega

Partitioning of a Hybrid Lipid in Domains of Saturated and Unsaturated Lipids in a Model Cellular Membrane

The Bures distance holds a special place among various distance measures due to its several distinguishing features and has applications in diverse problems in quantum information theory. It is related to fidelity, and among other things, it serves as a bona fide measure for quantifying the separability of quantum states. In this work, we calculate exact analytical results for the mean root fidelity and mean-square Bures distance between a fixed density matrix and a random density matrix and also between two random density matrices. In the course of derivation, we also obtain the spectral density for the product of the above pairs of density matrices. We corroborate our analytical results using Monte Carlo simulations. Moreover, we compare these results with the mean-square Bures distance between reduced density matrices generated using coupled kicked tops and find very good agreement. © 2021 American Physical Society.

Physical Review A

Random density matrices: Analytical results for mean root fidelity and the mean-square Bures distance

A uni-molecular layer of lipids at air-water interface mimicking one of the leaflets of the cellular membrane provides a simple model to understand the interaction of any foreign molecules with the membrane. Here, the interactions of protein Kalata B1 (KB1) of cyclotide family with the phospholipids 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), 1,2-dipalmitoyl-sn-glycero-3-phospho-rac-(1-glycerol) sodium salt (DPPG), and 1,2-distearoyl-sn-glycero-3-ethylphosphocholine chloride salt (DSEPC) have been investigated. The addition of KB1 induces a change in pressure of the lipid monolayers. The characteristic time of the change in pressure is found to be dependent on the electrostatic nature of the lipid. Even though the protein is weakly surface active, it is capable of modifying the phase behavior and elastic properties of lipid monolayers with differences in their strength and nature making the layers more floppy. The KB1-lipid interaction has been quantified by calculating the excess Gibb's free energy of interaction and the 1-anilino-8-naphthalenesulfonate (ANS) binding studies. The interaction with zwitterionic DPPC and negatively charged DPPG lipids are found to be thermodynamically favorable whereas the protein shows a weaker response to positively charged DSEPC lipid. Therefore, the long ranged electrostatic is the initial driving force for the KB1 to recognize and subsequently attach to a cellular membrane. Thereafter, the hydrophobic region of the protein may penetrate into the hydrophobic core of the membrane via specific amino acid residues. © 2021 Elsevier B.V.

International Journal of Biological Macromolecules

Interaction of cyclotide Kalata B1 protein with model cellular membranes of varied electrostatics

Graphene-based nano-technology is the future of biomedical devices including biosensors and, hence, it is essential to unravel the interaction of graphene oxide (GO) with cellular membrane. Here, the structural reorganization of lipid molecules, which are the building blocks of a cellular membrane, has been demonstrated in presence of GO flakes. The membrane is mimicked by forming a stack of lipid bilayers of zwitterionic phospholipid 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and its structures have been probed by X-ray reflectivity and grazing incidence X-ray diffraction techniques. Lipid-GO composites have exhibited two sets of lamellar diffraction peaks illustrating GO-rich micro-domains in the matrix of phospholipid bilayers (GO-poor phase). In these domains, the GO flakes are observed to penetrate into hydrophobic core of the bilayer altering the thickness along with the overall electron density profile of the lipid layer. The GO-poor bilayer is closely related to the phase formed by pristine lipid molecules. The lattice parameters of a body-centred rectangular unit cell formed by chains of saturated phospholipids are found to be modified in presence of GO with a significant effect on molecular tilt. The structural description of GO-membrane interaction may pave the way of discerning the physical behaviour of the composites. © 2020 Elsevier B.V.

Applied Surface Science

Unravelling the structural changes of phospholipid membranes in presence of graphene oxide

The Jacobi ensemble is one of the classical ensembles of random matrix theory. Prominent in applications are properties of the eigenvalues at the spectrum edge, specifically the distribution of the largest (e.g. Roy’s largest root test in multivariate statistics) and smallest (e.g. condition numbers of linear systems) eigenvalues. We identify three ranges of parameter values for which the gap probability determining these distributions is a finite sum with respect to particular bases, and moreover make use of a certain differential–difference system fundamental in the theory of the Selberg integral to provide a recursive scheme to compute the corresponding coefficients. © 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.

Ramanujan Journal

Computable structural formulas for the distribution of the β -Jacobi edge eigenvalues

<p>Inducement of high charge carrier density in organic field-effect transistors (OFETs) is a subject of immense interest due to its fundamental and applied impact on device operation. Here, the high performance of imidazolium-based ionic liquid (IL)-gated OFETs is reported. By exploiting the p-doping of poly(3-hexylthiophene-2,5diyl) (P3HT) in the ambient environment and using the IL-gating, high charge carrier density (1016 cm-2) has been induced in P3HT, which has resulted in high hole mobility (20.2 cm2 V-1 s-1). This is a remarkable improvement in field-effect mobility in organic polymer semiconductors. Along with high mobility, low threshold voltage (∼0.6 V), low subthreshold swing (∼100 mV dec-1), and specifically the high transconductance (&gt;1 mS) position this class of devices as a strong candidate for electrical sensor platforms. The compatibility of ILs with biomolecules and the direct access to IL/P3HT interface make these devices suitable for in situ biosensors. The IL components (cation and anion) were varied (one at a time) to investigate the effect on the electrical performance of the OFETs. An increase in the gate-electrode metal work function leads to a systematic decrease in the threshold voltage (by up to 0.6 V). The mobility exhibits a negative power dependence on specific capacitance, a signature of polaronic self-localization in organic semiconductors. The shelf life of the IL-gated OFETs is found to be more than 40 days. ©</p>