Physical, Psycho-social and Economic Burden of Chronic Obstructive Pulmonary Disease: A Hospital-Based Study in Kolkata, West Bengal, India

Abstract

MnBi 2 Te 4 , the first topological insulator with inherent magnetic ordering, has attracted significant attention recently for providing a platform to realize several exotic quantum phenomena at relatively higher temperatures. In this work, we have carried out an exhaustive investigation of MnBi 2 Te 4 and Sb doped MnBi 2 Te 4 thin films using THz time-domain spectroscopy. The extracted real THz conductivity displays a strong IR active E u phonon absorption peak (at ∼1.5 THz) merged on top of the Drude-like contributions from bulk and surface electrons. The extracted parameters from the THz conductivity data fitted to the Drude-Fano-Lorentz model, show significant changes in their temperature dependence around the magnetic ordering Néel temperature of ∼ 25K, which is suggestive of the coupling between magnetic ordering and electronic band structure. The frequency of the E u phonon displays an anomalous blue-shift with increasing temperatures by ∼ 0.1 THz (∼7%) for MnBi 2 Te 4 and ∼0.2 THz (∼13%) for Sb doped MnBi 2 Te 4 between 7K and 250K. The line-shape of the E u phonon mode in Sb doped MnBi 2 Te 4 shows significant Fano asymmetry compared to that of MnBi 2 Te 4 , indicating that Sb doping plays an important role in the Fano interference between the phonons and the electrons, in this system. These results indicate that the anomalous phonon behaviour seen in MBT arise mainly from positive cubic anharmonicity induced self energy parameter, whereas both anharmonicity and the electron phonon coupling are at play in making the relatively higher anomalous blue shift of phonons in MBST. Our studies provide the first comprehensive understanding of the phonon and electron dynamics of MnBi 2 Te 4 and Sb doped MnBi 2 Te 4 in the THz range using time-domain THz spectroscopy.

Detection and quantification of Ralstonia solanacearum through conventional and molecular techniques and spoilage in stored potato at different temperatures during storage

“…Brown rot of potato has been estimated to affect 3.75 million acres in approximately 80 countries with global damage estimates exceeding $950 million per year (Floyd, 2007) [4] . In India, R. solanacearum causes 50% crop loss in potato in a regular manner (Mukherjee and Dasgupta, 1989) [11] and up to 75% losses as reported in some areas of Karnataka (Gadewar et al, 1991) [5] . In India, bacterial wilt has become a limiting factor in potato cultivation, and cause losses in yield to the tune of 30 to 70% (Somani et al, 2010) [17] .…”