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Going beyond base-pairs: topology-based characterization of base-multiplets in RNA
No full textIdentification and characterization of base-multiplets, which are essentially mediated by base-pairing interactions, can provide insights into the diversity in the structure and dynamics of complex functional RNAs, and thus facilitate hypothesis driven biological research. The necessary nomenclature scheme, an extension of the geometric classification scheme for base-pairs by Leontis and Westhof, is however available only for base-triplets. In the absence of information on topology, this scheme is not applicable to quartets and higher order multiplets. Here we propose a topology-based classification scheme which, in conjunction with a graph-based algorithm, can be used for the automated identification and characterization of higher order base-multiplets in RNA structures. Here, the RNA structure is represented as a graph, where nodes represent nucleotides and edges represent base-pairing connectivity. Sets of connected components (of n nodes) within these graphs constitute subgraphs representing multiplets of ``n'' nucleotides. The different topological variants of the RNA multiplets thus correspond to different nonisomorphic forms of these subgraphs. To annotate RNA base-multiplets unambiguously, we propose a set of topology-based nomenclature rules for quartets, which are extendable to higher multiplets. We also demonstrate the utility of our approach toward the identification and annotation of higher order RNA multiplets, by investigating the occurrence contexts of selected examples in order to gain insights regarding their probable functional roles
Magnetic ground state, field-induced transitions, electronic structure, and optical band gap of the frustrated antiferromagnet GeCo2O4
No full textSystematic studies of magnetic ordering, magnetic-field-induced transitions, electronic structure, and optical properties of the frustrated spinel GeCo2O4 (GCO) are reported. Our results reveal that GCO orders antiferro-magnetically (AFM) at T-N = 20.4 K but with significant short-range ferromagnetic (FM) order up to T similar to 5 T-N. The paramagnetic susceptibility (chi) fits the modified Curie-Weiss law, chi = chi(o) + C/(T - theta), with theta = +51 K for 100 K < T < 800 K. The fit to high-temperature-series expansion of chi (T) yields J(1)/k(B) = 14.7 K as the dominant FM exchange coupling for the pyrochlore lattice of Co2+ spins consisting of alternate planes of Kagome (KGM) and Triangular (TRI) spins lying perpendicular to 111] direction. From the analysis of the M-H plots at 2 K and published results, three critical fields are identified: H-d similar to 11 kOe due to AFM domains, H-C1 approximate to 44 kOe related to spin-flips and FM ordering of the TRI spins, and H-C2 approximate to 97 kOe related to FM ordering of the KGM spins. For H > H-C2, GCO is a forced ferromagnet with some canting of the spins. Magnetic field dependence of T-N follows the relation T-N (H) = T-N(0)-D1H2 valid for antiferromagnets with D-1 = 6.63 x 10(-10) K/Oe(2). This magnitude of T-N(H) along with the temperature dependence of H-d, H-C1, and H-C2 are used to construct the H-T phase diagram. From the magnitudes of the Curie constant (C) and the saturation magnetization at 2 K it is shown that Co2+ ions in GCO have the ground state with effective spin S = 1/2. High resolution x-ray photoelectron spectra of 2p and 3d orbitals of Co and Ge confirm the divalent and tetravalent electronic states of Co and Ge, respectively, in GCO. The energy band gap (E-g = 3.28 eV) evaluated using DFT+U calculations is in good agreement with the experimental results (E-g = 3.16 eV) obtained from the diffuse reflectance spectroscopy
Synthesis of highly magnetic Mn-Zn ferrite (Mn0.7Zn0.3Fe2O4) ceramic powder and its use in smart magnetorheological fluid
No full textManganese-zinc ferrite (Mn0.7Zn0.3Fe2O4) powder containing irregular-shaped particles with high saturation magnetization and high magnetic softness was synthesized via solution combustion method. By dispersing these magnetic ceramic particles in silicone oil, a magnetorheological fluid (MRF) was prepared and its magneto-mechanical property was studied. The yield strength ((Y)) exhibited by the MRF increases with increase in applied magnetic field, and a very high value of yield strength of similar to 10.5kPa (at B=1.2T) was observed. The viscosity () of the MRF also increases with B due to increased inter-particle magnetic interaction. The low density, low cost of the precursors and the industrial scalability of the Mn-Zn ferrite powder-production render these powders suitable for large-scale device applications. In addition, the thermal, oxidative and chemical stabilities of these ferrimagnetic oxide ceramics are advantageous for their application in corrosive and high temperature environments
Delocalization and Quantum Entanglement in Physical Systems
No full textQuantum coherence and entanglement in an extended interacting system where energy levels are nondegenerate and coupled to a dissipative environment is a common occurrence in nature, like in photosynthetic reaction systems and conjugated polymers. The temperature dependence of quantum coherence in a trimer complex (first three subunits of the Fenna-Matthews-Olson complex) is studied using a temperature dependent quantum stochastic Liouville equation. In the non-Markovian limit, the lowering of temperature induces long-lasting quantum coherence that, in turn, leads to delocalization, whose length grows. The entanglement and coherence length determine the nature of the dynamic localization
PA-Fuse: deep supervised approach for the fusion of photoacoustic images with distinct reconstruction characteristics
No full textThe methods available for solving the inverse problem of photoacoustic tomography promote only one feature-either being smooth or sharp-in the resultant image. The fusion of photoacoustic images reconstructed from distinct methods improves the individually reconstructed images, with the guided filter based approach being state-of-the-art, which requires that implicit regularization parameters are chosen. In this work, a deep fusion method based on convolutional neural networks has been proposed as an alternative to the guided filter based approach. It has the combined benefit of using less data tbr training without the need for the careful choice of any parameters and is a fully data-driven approach. The proposed deep fusion approach outperformed the contemporary fusion method, which was proved using experimental, numerical phantoms and in-vivo studies. The improvement obtained in the reconstructed images was as high as 95.49% in root mean square error and 7.77 dB in signal to noise ratio (SNR) in comparison to the guided filter approach. Also, it was demonstrated that the proposed deep fuse approach, trained on only blood vessel type images at measurement data SNR being 40 dB, was able to provide a generalization that can work across various noise levels in the measurement data, experimental set-ups as well as imaging objects. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreemen
A NEW SPECIES OF PITVIPER (SERPENTES: VIPERIDAE: Trimeresurus LACEPEDE, 1804) FROM WEST KAMENG DISTRICT, ARUNACHAL PRADESH, INDIA
No full textA new species of pitviper, Trimeresurus arunachalensis sp. nov., is described based on a single specimen. It differs from all known congeners by the following combination of characters - 19:17:15 acutely keeled dorsal scale rows (except first row - keeled or smooth); overall reddish-brown coloration; white dorsolateral stripe on outer posterior edges of ventrals and sometimes first dorsal scale row; 7 supralabials; 6 - 7 scales between supraoculars; 145 ventrals; 51 paired subcaudals (excluding the terminal scale); single anal; a sharply defined canthus rostralis with the margin overhanging the loreal region; a distinctly concave rostral scale with the upper edge projecting well beyond its lower margin; an unforked, attenuate hemipenis that extends to the 8th subcaudal scale. and has no visible spines. DNA phylogenetic analysis indicates that the new species is distinct from congeners and nested well within the Trimeresurus Glade. The closest relative based on available DNA data is T. tibetanus. The new species is presently known from a single locality - Ramda, West Kameng, Arunachal Pradesh, northeastern India
Design and Simulation of Effective 90 degrees Bend Waveguide Based on Hexagonal Lattice Photonic Crystal
No full textOne area of silicon photonics that has attracted attention lately is that of Photonic Crystal(PhC) components. Passive components based on 2D Photonic Crystals have experienced major developments in the last few years. PhCs extends an optimistic stand for upcoming small scale ICs over optical communication. The disadvantage of conventional waveguides is that, they gives high transmission loss during the light passing through sharp corners. This loss can be minimized by adjusting the fiber bending radius such that it should be several times higher than transmission wavelengths used. We can overcome the difficulties by using Photonic Crystals having Band Gaps. Photonic Crystals are considered for minimization of optical power loss during sharp bending and splitting. In this paper we focus on the design of effective 90 degrees bend waveguide by using three channel waveguides with two 60 degrees bends by using hexagonal lattice. The optical modelling of the proposed structures are investigated by using 2-D Finite Difference Time Domain (FDTD) method
Measurement of associated production of a W boson and a charm quark in proton-proton collisions at root s=13 Tev
No full textMeasurements are presented of associated production of a W boson and a charm quark (W + c) in proton-proton collisions at a center-of-mass energy of 13 TeV. The data correspond to an integrated luminosity of 35.7 fb(-1) collected by the CMS experiment at the CERN LHC. The W bosons are identified by their decay into a muon and a neutrino. The charm quarks are tagged via the full reconstruction of D* (2010)(+/-) mesons that decay via D*(2010)(+/-) D-0 + pi(+/-) -> K--/+ + pi(+/-) + pi(+/-). A cross section is measured in the fiducial region defined by the muon transverse momentum p(T)(mu) > 26 GeV, muon pseudorapidity vertical bar eta(mu)vertical bar < 2.4, and charm quark transverse momentum p(T)(c) > 5 GeV. The inclusive cross section for this kinematic range is sigma(W + c) = 1026 +/- 31(stat)(-72)(+76) pb. The cross section is also measured differentially as a function of the pseudorapidity of the muon from the W boson decay. These measurements are compared with theoretical predictions and are used to probe the strange quark content of the proton
Model based approach for planning dynamic integration of renewable energy in a transitioning electricity system
No full textReality of climate change threats have spurred mitigation interventions across the world. For electricity sector, the interventions are predominantly in terms of mainstreaming renewable energy sources. Consequently, there is a consistent increase in the share of renewable energy-based electricity systems which has caused emergence of several new challenges. The challenges have emerged both with respect to planning and management of the transitioning electricity systems. These new challenges are because of shift away from supply-chain influenced conventional energy resource supply to nature influenced dynamic renewable energy resource supply; shift from conventional firm power to renewable intermittent power; operational complexities due to frequent and steeper ramps; and need for matching dynamic demand for power. We propose, develop and validate a novel approach for better representation of these resource-supply-demand dynamics in evolving suite of generation expansion models with operational details. First, we discuss development of an electricity generation expansion planning model with operational details. Second, to model the dynamic nature of renewable energy resources and demand for power, we develop an approach for generating annual wind and solar resource profiles, and representative load curves respectively, and harmonizing them before they are fed into the generation expansion model. We validate this approach using India's electricity system data and use the model to evaluate implications of varying levels of renewable energy integration. We find that this increased penetration of renewable energy while bringing significant climate change benefits creates substantial capacity redundancy leading to lower capacity utilization of the overall system
Na2FePO4F Fluorophosphate as Positive Insertion Material for Aqueous Sodium-Ion Batteries
No full textExploring stable and economic cathodes for aqueous sodium-ion batteries, we have investigated iron-based fluorophosphate (Na2FePO4F) as a compound for applications in aqueous battery systems. Solution combustion synthesized Na2FePO4F is found to act as an efficient cathode for aqueous Na-ion batteries delivering a reversible capacity over 85 mAh g(-1) (at a rate of 1 mA cm(-2)) with excellent rate kinetics. Further, this layered Na2FePO4F has been successfully implemented to design a full aqueous cell with NASICON-type NaTi2(PO4)(3) as anode, delivering a reversible capacity of 90 mAh g(-1). In conclusion, Na2FePO4F is proposed as a potential cathode material for aqueous Na-ion batteries