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Quantum correlations in neutrino oscillations in curved spacetime
No full textGravity induced neutrino-antineutrino oscillations are studied in the context of one- and two-flavor scenarios. This allows one to investigate the particle-antiparticle correlations in two and four level systems, respectively. Flavor entropy is used to probe the entanglement in the system. The well known witnesses of nonclassicality such as Mermin and Svetlichny inequalities are investigated. Since the extent of neutrino-antineutrino oscillation is governed by the strength of the gravitational field, the behavior of nonclassicality shows interesting features as one varies the strength of the gravitational field. Specifically, the suppression of the entanglement with the increase of the gravitational field is observed which is witnessed in the form of decrease in the flavor entropy of the system. The features of the Mermin and the Svetlichny inequalities allow one to make statements about the degeneracy of neutrino mass eigenstates
Evaluating the predictions of the protein stability change upon single amino acid substitutions for the FXN CAGI5 challenge
No full textFrataxin (FXN) is a highly conserved protein found in prokaryotes and eukaryotes that is required for efficient regulation of cellular iron homeostasis. Experimental evidence associates amino acid substitutions of the FXN to Friedreich Ataxia, a neurodegenerative disorder. Recently, new thermodynamic experiments have been performed to study the impact of somatic variations identified in cancer tissues on protein stability. The Critical Assessment of Genome Interpretation (CAGI) data provider at the University of Rome measured the unfolding free energy of a set of variants (FXN challenge data set) with far-UV circular dichroism and intrinsic fluorescence spectra. These values have been used to calculate the change in unfolding free energy between the variant and wild-type proteins at zero concentration of denaturant (Delta Delta GH2O). The FXN challenge data set, composed of eight amino acid substitutions, was used to evaluate the performance of the current computational methods for predicting the Delta Delta GH2O value associated with the variants and to classify them as destabilizing and not destabilizing. For the fifth edition of CAGI, six independent research groups from Asia, Australia, Europe, and North America submitted 12 sets of predictions from different approaches. In this paper, we report the results of our assessment and discuss the limitations of the tested algorithms
Hydrogen Sulfide Gas Sensing Capabilities of Solution Processed Vanadium Pentoxide Nanosheets
No full textVanadium Pentoxide (V2O5) nanosheets, liquid exfoliated in ethanol, were used as sensing material for hydrogen sulfide (H2S) detection. The material properties such as morphology, phase, chemical signature were characterized using Field Emission electron microscopy (FESEM), Transmission electron microscopy (TEM), Atomic force microscopy (AFM), X-ray Diffraction (XRD), Raman Spectroscopy, X-ray photoelectron microscopy (XPS). These nanosheets were further dropcasted on Ti/Pt interdigitated electrode (IDE) to fabricate a chemiresistive gas sensing device. The sensors show excellent response towards H2S gas at an operating temperature of 350 degrees C, when operated in 500 ppb-4 ppm range. The response in this range was found to be varying linearly from 1.5% (for 500 ppb) to 12.8% (for 4 ppm). Response time and recovery time of 71 seconds and 104 seconds for 1 ppm H2S was observed. The hysteresis error (%) of the device was found to be +/- 4.21% which suggests it to be a good sensing material for H2S detection. The device was also tested on other parameters like repeatability, stability and reproducibility and it performs well in these tests indicating exfoliated V2O5 nanosheet as a potential sensing material for chemiresistive devices for H2S detection
Futuristic medical implants using bioresorbable materials and devices
No full textImplantable medical devices have been used for real-time monitoring of physical parameters (temperature, pressure and biopotentials), sustained drug release, cardiovascular and pulmonary stents and other clinical applications. Several biocompatible materials (titanium and its alloys, aluminium, cobalt-alloys, stainless steel, poly-ethylene, polyurethanes, polyglycolide and polylactides) have been commercially used for fabricating implantable devices. However, these devices require retrieval operations after a certain period. Bioresorbable materials disintegrate gradually in vivo and their derivatives get absorbed completely in the body fluid with no residue and with minimal toxic effects, thus, eliminating the need for retrieval operations. In this article, state-ofthe-art advances in materials, fabrication techniques and clinical applications of bioresorbable implantable devices are reviewed. We first discuss the bioresorbable materials (e.g., magnesium, molybdenum, tungsten, silicon, germanium, silicon dioxide, silicon nitride, silk and synthetic polymers) used in the fabrication of implantable devices. Later, an overview of processes to fabricate pressure, temperature, electrical and chemical sensors are discussed, followed by their applications as implantable devices in biomedical engineering
Manganese-Catalysed C-H Activation: A Regioselective C-H Alkenylation of Indoles and other (hetero)aromatics with 4-Hydroxy-2-Alkynoates Leading to Concomitant Lactonization
No full textA manganese-catalyzed C-H bond alkenylation of indoles at C2-position with 4-hydroxy-2-alkynoates leading to concomitant lactonization under removable directing group strategy has been disclosed. This lactonization strategy exhibits regioselectivity, a broad substrate scope, and a good functional group tolerance furnishing the products in low to high yields. The regioselectivity is guided by the electronic effect of the ester group as well as the steric bulk at the C4-position of the 4-hydroxy-2-alkynoates. After the reaction, the directing group has been readily removed to obtain N-H free indole
Tavorite LiFePO4OH hydroxyphosphate as an anode for aqueous lithium-ion batteries
No full textIn pursuit to find stable economic anode for aqueous lithium-ion batteries, tavorite structured LiFePO4OH hydroxyphosphate has been investigated in aqueous battery for the first time. First, the target compound is tested with organic electrolyte, giving the highest reported discharge capacity of 140 mAh g(-1) with an Fe3+/Fe2+ redox potential of 2.6 V with excellent reversibility. LiFePO4OH is found to work as a promising anode in aqueous electrolyte with capacity similar to 153 mAh g(-1) (at 0.42 V vs. Ag/AgCl) with good cycling stability. An all-phosphate LiFePO4 vertical bar LiFePO4OH aqueous full cell has been fabricated having the first cycle capacity of 120 mAh g(-1) (energy density similar to 97 Wh kg(-1)). Tavorite LiFePO4OH forms an economic potential anode for aqueous Li-ion batteries
Dual role for fungal-specific outer kinetochore proteins during cell cycle and development in Magnaporthe oryzae
No full textThe outer kinetochore DASH complex (also known as the Dam1 complex) ensures proper spindle structure and chromosome segregation. While DASH complex protein requirement diverges among different yeasts, its role in filamentous fungi has not yet been investigated. We studied the dynamics and role of middle (Mis12) and outer (Dam1 and Ask1) kinetochore proteins in the filamentous fungal pathogen, Magnaporthe oryzae, which undergoes multiple cell cyclelinked developmental transitions. While Mis12 was constitutively present in the nucleus, Dam1 and Ask1 were recruited only during mitosis. Although Dam1 was not required for viability, loss of its function (dam1 Delta) delayed mitotic progression, resulting in impaired conidial and hyphal development. Both Dam1 and Ask1 also localised to the hyphal tips, in the form of punctae oscillating back and forth from the growing ends, suggesting that Magnaporthe DASH complex proteins may play a non-canonical role in polarised growth during interphase, in addition to their function in nuclear segregation during mitosis. Impaired appressorial (infection structure) development and host penetration in the dam1. mutant suggest that fungus-specific Dam1 complex proteins could be an attractive target for a novel anti-fungal strategy
To leave or to stay: direct fitness through natural nest foundation in a primitively eusocial wasp
No full textDispersing from the natal nest to found new nests is an avenue for gaining direct fitness for workers in some primitively eusocial insects, especially in species with a perennial nesting cycle where males are present throughout the year. Such nest foundation is difficult to study in nature or in small laboratory cages. Hence, we have investigated the dynamics of nest foundation by workers of the primitively eusocial wasp Ropalidia marginata inside closed walk-in cages so that we could locate and observe every event of nest foundation. Starting with nine parent nests we observed the dispersal of female workers that initiated 9 single-foundress and 20 multiple-foundress nests. Wasps congregated outside their parent nests and engaged in dominance-subordinate interactions before initiating multiple foundress nests. The most dominant wasps of such aggregations became queens, and among the others, some joined the new nests as cofoundresses to become workers while the others remained in the parent nests. Solitary foundresses never participated in such off-nest aggregations. Solitary foundresses and future queens of multiple foundress nests engaged in self-feeding behaviour outside their parent nests, a behaviour not performed by wasps that did not initiate new nests. Queens of new nests gained immediate direct fitness. Although the cofoundresses continued to gain only indirect fitness, they are expected to have a higher probability of gaining direct fitness in the future as compared to the corresponding probability in their much larger parent nests. These findings underscore the importance of direct fitness in the evolution of cooperation in primitively eusocial insects
Template-Free Synthesis of ``Wool-Ball''-Like Hollow CuS Structures Can Effectively Suppress Electromagnetic Radiation: A Mechanistic Insight
No full textLightweight and easy to fabricate and integrate microwave absorbers are in great demand both in commercial space as well as in stealth applications given the surge in the use of wireless communication. In the past decade, research on designing polymer nanocomposite based microwave absorbers containing magnetic and conducting nanoparticles has swollen significantly; however, a clear mechanistic insight on the usage of semiconductors is far away. Herein, the potential of ``wool-ball''-like hollow semiconductor (CuS, copper sulfide) structures is explored for microwave absorption, and a mechanistic insight is proposed based on the experimental evidence. The facile synthesis approach, unique morphological structure, and optical properties make this semiconductor (CuS) quite attractive for the proposed application. In addition, the systematic analysis reveals that this material has the potential to replace the conventional conducting or magnetic nanoparticles, due to its favorable skin depth and microwave attenuation capability through dielectric heating and polarization loss. Polyvinylidene fluoride (PVDF) composites containing hollow CuS structures exhibited shielding effectiveness of 44 dB at 18 GHz, of which 86% of the incident radiation was attenuated by absorption. Further, thermal dissipation ability of this composite and its correlation with real-time microwave exposure through time-temperature response have offered new avenues in the design of microwave absorbers
Nano-second timescale high-field phase transition in hydrogenated amorphous silicon
No full textIn this work, we report the phase transition behavior of hydrogenated amorphous silicon on the application of nanosecond timescale high-field pulse electrical stress. The transition of amorphous silicon to nanocrystalline silicon, confirmed through Raman spectroscopy, is marked by an abrupt change in the pulse I-V characteristics. The mechanism of the phase transition at high electric field involving the avalanche generation of charge carriers and optical phonon generation is discussed. The role of defect states in optical phonon localization and eventual phase transition is explored. The phase transition in the case of devices with a drain-gate underlap is also studied. The role of self-heating in accelerating the phase transition has also been explored. The impact of channel dimensions on the onset of the phase transition is also discussed. Characterization of the resultant nc-Si is done through deconvolution of the Raman spectra, and the quality of nc-Si created is found comparable to earlier studies