Global perspectives on the energy landscapes of liquids, supercooled liquids, and glassy systems: geodesic pathways through the potential energy landscape

How useful it is to think about the potential energy landscape of a complex many-body system depends in large measure on how direct the connection is to the system's dynamics. In this paper we show that, within what we call the potential-energy-landscape ensemble, it is possible to make direct connections between the geometry of the landscape and the long-time dynamical behaviors of systems such as supercooled liquids. We show, in particular, that the onset of slow dynamics in such systems is governed directly by the lengths of their geodesics--the shortest paths through their landscapes within the special ensemble. The more convoluted and labyrinthine these geodesics are, the slower that dynamics is. Geodesics in the landscape ensemble have sufficiently well-defined characteristics that it is straightforward to search for them numerically, a point we illustrate by computing the geodesic lengths for an ordinary atomic liquid and a binary glass-forming atomic mixture. We find that the temperature dependence of the diffusion constants of these systems, including the precipitous drop as the glass-forming system approaches its empirical mode-coupling transition, is predicted quantitatively by the growth of the geodesic path lengths.     

Bioconcentration of zinc and its effect on the biochemical constituents of the gill tissues of Labeo rohita: An FT-IR study

In the present work, an attempt has been made to assess the bioconcentration and distribution of zinc on the selected organs of Labeo rohita and to study the effect of zinc exposure on the biochemical constitutions of gill tissues of L. rohita by using FT-IR Spectroscopy. The concentration pattern in the organs reveals that the liver is the prime site of metal binding and muscle accumulates least metal concentration. The accumulation profile is in the order: liver > gill > kidney > brain > bone > muscle. It has also been observed that the administration of chelating agent d-Penicillamine (DPA) reduces the zinc concentration in all tissues more effectively than the administration of the chelating agent Ethylene Diamine Tetra Acetic acid. The FT-IR spectra reveal that zinc exposure causes significant changes in the biochemical constitutions of the gill tissues. It causes an alteration in the protein secondary structures by decreasing the α-helix and increasing the β-sheet contents. Further, it has been observed that the administration of chelating agent DPA improves the protein and lipid contents in the gill tissues compared to zinc exposed tissues. This result shows that DPA is the effective chelator of zinc in reducing the body burden of L. rohita fingerlings. In conclusion, the findings of the current study suggest that zinc exposure causes significant changes in both lipids and proteins of the gill tissues, and changes the protein profile in favour of β-sheet structure.