Synthesis and structure of two phases with both extended and point defects: Mn1 - xBi2 + yS4 and Mn1 - xBi2 + ySe4

We report the structures of Mn1 - xBi2 + yS4 (0 [les] x [les] 0.3; Y = 0.667x) and Mn1 - xBi2 + ySe4 (0.1 [les] x [les] 0.14; Y = 0.667x). Both compounds are defect structures of the HgBi2S4 structure type. In the case of Mn0.7Bi2.2S4 we report a single crystal structure. The cell parameters are a = 12.869(2) A, B = 3.9546(6) A, C = 14.771(2) A, [beta] = 116.690(9)o and the space group is C2/m. Final refinement gave the values R/Rw = 3.3/3.7%. This crystal was grown in an alkali halide flux. The reported compounds belongs to the family of chemically twinned face-centered cubic (f.c.c.) structures. Unlike most members of this family, they exhibit both extended defects and point defects.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/30736/1/0000385.pd

Virtual screening of the inhibitors targeting at the viral protein 40 of Ebola virus

Multilingual abstracts in the six official working languages of the United Nations. (PDF 373 kb

ESR studies of inter- and intra-lamellar cation exchange processes in Cd2P2S6

The transition metal chalcogenides, M2P2S6 (M = divalent transition metal cation), are lamellar materials that undergo an unusual cation exchange process when their crystals are placed in contact with a solution of a transition metal salt. EPR spectroscopy has been used to examine the exchange of paramagnetic Co2+ for Cd2+ in diamagnetic Cd2P2S6. It has been possible to study the uptake of ions by the lamellar lattice and to examine the cation coordination environment through its effect on the parameters of the spin-Hamiltonian. In order to extract details of the Co2+ coordination from the observed EPR spectra, theoretical values of the g-value have been computed as a function of several crystal field parameters. The results for Co2+ are compared with previous results for the insertion of Mn2+ into Cd2P2S6 by cation exchange. The relative occupancy of the inter- and intra-lamellar sites is a function of the cation type and the solvent employed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/28953/1/0000790.pd

Investigating the Structural Impacts of I64T and P311S Mutations in APE1-DNA Complex: A Molecular Dynamics Approach

Elucidating the molecular dynamic behavior of Protein-DNA complex upon mutation is crucial in current genomics. Molecular dynamics approach reveals the changes on incorporation of variants that dictate the structure and function of Protein-DNA complexes. Deleterious mutations in APE1 protein modify the physicochemical property of amino acids that affect the protein stability and dynamic behavior. Further, these mutations disrupt the binding sites and prohibit the protein to form complexes with its interacting DNA.In this study, we developed a rapid and cost-effective method to analyze variants in APE1 gene that are associated with disease susceptibility and evaluated their impacts on APE1-DNA complex dynamic behavior. Initially, two different in silico approaches were used to identify deleterious variants in APE1 gene. Deleterious scores that overlap in these approaches were taken in concern and based on it, two nsSNPs with IDs rs61730854 (I64T) and rs1803120 (P311S) were taken further for structural analysis.Different parameters such as RMSD, RMSF, salt bridge, H-bonds and SASA applied in Molecular dynamic study reveals that predicted deleterious variants I64T and P311S alters the structure as well as affect the stability of APE1-DNA interacting functions. This study addresses such new methods for validating functional polymorphisms of human APE1 which is critically involved in causing deficit in repair capacity, which in turn leads to genetic instability and carcinogenesis

FTIR electronic spectra of Fe2P2S6 and Co2P2S2: Trigonal field splitting and lithium intercalation effects

The FTIR electronic absorption spectra of single crystals of Fe2P2S6, Co2P2S6 and their lithium intercalation compounds have been obtained. The spectrum of Fe2P2S6 exhibits a broad, weak absorption feature at 1885 cm-1 and a second, stronger band at 8870 cm-1. These are assigned to transitions between the 5Eg (ground state) and the 5A1g and 5Eg trigonal crystal-field components of the Fe2+ free-ion 5D ground term. The broad absorption bands in the spectrum of Co2P2S6 are assigned to the transitions between the 4A2g (ground state) and the 4Eg (1224cm-1) and 4A1g (7124 cm-1) trigonal crystal-field components of the Co2+ free-ion 4F ground term. A point-charge crystal-field model was used to relate the crystal-field splitting parameters (Dq and Cp) to the trigonal lattice distortion.Lithium intercalation completely suppresses the trigonal field transition in Co2P2S6 and causes a dramatic shift of the absorption edge to lower frequencies. However, lithium intercalation has little effect upon the spectrum of Fe2P2S6.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/28145/1/0000597.pd