79 research outputs found
Theoretical study on hydrogen storage capacity of expanded h-BN systems
In this work, the hydrogen storage capacity of the expanded hexagonal Boron Nitride (eh-BN) systems has been presented. We have employed a new equation of state (EOS) for hydrogen gas to figure out the hydrogen density distribution profiles in the eh-BN systems. In this regard, the environmental conditions (i.e., temperature and pressure) are considered in the prediction procedure using DFT single point calculations. The eh-BN systems with different layer spacings are studied by PBE method with consideration of the long range dispersion corrections. On account of the in-plane polar bonds, a series of adsorption positions are considered. Additionally, the adsorption energy and hydrogen density profiles are reported. Furthermore, the relation between uptakes and the interlayer spacings with the effects of the environmental conditions are also provided. The limit of the physical hydrogen storage capacity in a perfect eh-BN system at 243 K and 10 MPa is founded to be 2.96 wt.%.--//--eng Fu, Jing Wang, Ran Jia, Shamsa Bibi, Roberts I. Eglitis, Hong-Xing Zhang, Theoretical study on hydrogen storage capacity of expanded h-BN systems, Computational Materials Science, Volume 139, 2017, Pages 335-340, ISSN 0927-0256,
https://doi.org/10.1016/j.commatsci.2017.08.015 published under the CC BY licence.Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Unionās Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017 TeamingPhase2 under grant agreement No. 739508, project CAMART2
Recombination analysis based on the complete genome of bocavirus
Bocavirus include bovine parvovirus, minute virus of canine, porcine bocavirus, gorilla bocavirus, and Human bocaviruses 1-4 (HBoVs). Although recent reports showed that recombination happened in bocavirus, no systematical study investigated the recombination of bocavirus. The present study performed the phylogenetic and recombination analysis of bocavirus over the complete genomes available in GenBank. Results confirmed that recombination existed among bocavirus, including the likely inter-genotype recombination between HBoV1 and HBoV4, and intra-genotype recombination among HBoV2 variants. Moreover, it is the first report revealing the recombination that occurred between minute viruses of canine
Mining risk patterns in medical data
In this paper, we discuss a problem of finding risk patterns in medical data. We define risk patterns by a statistical metric, relative risk, which has been widely used in epidemiological research. We characterise the problem of mining risk patterns as an optimal rule discovery problem. We study an anti-monotone property for mining optimal risk pattern sets and present an algorithm to make use of the property in risk pattern discovery. The method has been applied to a real world data set to find patterns associated with an allergic event for ACE inhibitors. The algorithm has generated some useful
results for medical researchers
MiR-195 affects cell migration and cell proliferation by down-regulating DIEXF in Hirschsprungās Disease
A Priori Error Estimates for Least-Squares Mixed Finite Element Approximation of Elliptic Optimal Control Problems
Direct Phasing of Coiled-Coil Protein Crystals
Coiled-coil proteins consisting of multiple copies of helices take part in transmembrane transportation and oligomerization, and are used for drug delivery. Cross-alpha amyloid-like coiled-coil structures, in which tens of short helices align perpendicular to the fibril axis, often resist molecular replacement due to the uncertainty to position each helix. Eight coiled-coil structures already solved and posted in the protein data bank are reconstructed ab initio to demonstrate the direct phasing results. Non-crystallographic symmetry and intermediate-resolution diffraction data are considered for direct phasing. The retrieved phases have a mean phase error around 30∼40°. The calculated density map is ready for model building, and the reconstructed model agrees with the deposited structure. The results indicate that direct phasing is an efficient approach to construct the protein envelope from scratch, build each helix without model bias which is also used to confirm the prediction of AlphaFold and RosettaFold, and solve the whole structure of coiled-coil proteins
Direct Phasing of Coiled-Coil Protein Crystals
Coiled-coil proteins consisting of multiple copies of helices take part in transmembrane transportation and oligomerization, and are used for drug delivery. Cross-alpha amyloid-like coiled-coil structures, in which tens of short helices align perpendicular to the fibril axis, often resist molecular replacement due to the uncertainty to position each helix. Eight coiled-coil structures already solved and posted in the protein data bank are reconstructed ab initio to demonstrate the direct phasing results. Non-crystallographic symmetry and intermediate-resolution diffraction data are considered for direct phasing. The retrieved phases have a mean phase error around 30ā¼40Ā°. The calculated density map is ready for model building, and the reconstructed model agrees with the deposited structure. The results indicate that direct phasing is an efficient approach to construct the protein envelope from scratch, build each helix without model bias which is also used to confirm the prediction of AlphaFold and RosettaFold, and solve the whole structure of coiled-coil proteins
Molecular Insights into the Heterotropic Allosteric Mechanism in Cytochrome P450 3A4-Mediated Midazolam Metabolism
Cytochrome P450 3A4 (CYP3A4) is the main P450 enzyme
for drug metabolism
and drugādrug interactions (DDIs), as it is involved in the
metabolic process of approximately 50% of drugs. A detailed mechanistic
elucidation of DDIs mediated by CYP3A4 is commonly believed to be
critical for drug optimization and rational use. Here, two typical
probes, midazolam (MDZ, substrate) and testosterone (TST, allosteric
effector), are used to investigate the molecular mechanism of CYP3A4-mediated
heterotropic allosteric interactions, through conventional molecular
dynamics (cMD) and well-tempered metadynamics (WT-MTD) simulations.
Distance monitoring shows that TST can stably bind in two potential
peripheral sites (Site 1 and Site 2) of CYP3A4. The binding of TST
at these two sites can induce conformational changes in CYP3A4 flexible
loops on the basis of conformational analysis, thereby promoting the
transition of the MDZ binding mode and affecting the ratio of MDZ
metabolites. According to the results of the residue interaction network,
multiple allosteric communication pathways are identified that can
provide vivid and applicable insights into the heterotropic allostery
of TST on MDZ metabolism. Comparing the regulatory effects and the
communication pathways, the allosteric effect caused by TST binding
in Site 2 seems to be more pronounced than in Site 1. Our findings
could provide a deeper understanding of CYP3A4-mediated heterotropic
allostery at the atomic level and would be helpful for rational drug
use as well as the design of new allosteric modulators
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