The mechanism of interaction relation between the rare-earth element Ce and elements Pb and Bi in Ag-based filler metal has been studied. The results show that the compounds CePb and CeBi with high melting point can b...The mechanism of interaction relation between the rare-earth element Ce and elements Pb and Bi in Ag-based filler metal has been studied. The results show that the compounds CePb and CeBi with high melting point can be easily produced between these three elements in the filler metal, which greatly limited the formation of the isolated phase Pb or Bi and also eliminated the bad effect of impurity elements Pb and Bi on the spreading property of Ag-based filler metal. The metallurgical and quantum-mechanical bond formation analysis show that a strong chemical affinity was existed between the rare-earth element Ce and impurity elements Pb and Bi, which was proved by the XRD analysis results.展开更多
β-amyloid(Aβ)deposits are the leading cause of Alzheimer's disease.Many studies have confirmed that transthyretin(TTR)inhibits the cytotoxicity of Aβoligomers(AβOs)with various species(oligomers and protofibri...β-amyloid(Aβ)deposits are the leading cause of Alzheimer's disease.Many studies have confirmed that transthyretin(TTR)inhibits the cytotoxicity of Aβoligomers(AβOs)with various species(oligomers and protofibrils,but not monomers)through their interactions.Here,we investigated the mechanisms of interactions between the TTR tetramer and various Aβspecies,including two monomers with different morphologies and four oligomers with different molecular weights,by employing molecular dynamics simulations.From these results,we propose a clear interaction scenario:upon AβO binding,the dimer-dimer distance of TTR increases and the binding energy decreases,indicating an unfavorable effect on the TTR stability.Moreover,the larger the molecular weight(MW)of AβO,the greater the effect of interaction between the TTR tetramer and Aβoligomer,and consequently the worse the TTR stability.In turn,Aβ–Aβintermolecular distances in AβO grow and the hydrophobic solvent-accessible surface area(SASA)increases,whereas the number of intermolecular hydrogen bonds decreases,indicating AβO disaggregation induced by the TTR binding.Moreover,a trend is observed for the disaggregation to increase as the MW of the AβO species increases.Finally,we reveal that conformations rich in helical sections rather than the semi-extended conformation are favored upon binding with TTR.Overall,this study provides a comprehensive molecular-level insight to better understand the mechanism and principles of interaction between the TTR tetramer and AβOs.展开更多
文摘The mechanism of interaction relation between the rare-earth element Ce and elements Pb and Bi in Ag-based filler metal has been studied. The results show that the compounds CePb and CeBi with high melting point can be easily produced between these three elements in the filler metal, which greatly limited the formation of the isolated phase Pb or Bi and also eliminated the bad effect of impurity elements Pb and Bi on the spreading property of Ag-based filler metal. The metallurgical and quantum-mechanical bond formation analysis show that a strong chemical affinity was existed between the rare-earth element Ce and impurity elements Pb and Bi, which was proved by the XRD analysis results.
基金supported by the Shandong Provincial Natural Science Foundation(ZR2022MB073)of China.
文摘β-amyloid(Aβ)deposits are the leading cause of Alzheimer's disease.Many studies have confirmed that transthyretin(TTR)inhibits the cytotoxicity of Aβoligomers(AβOs)with various species(oligomers and protofibrils,but not monomers)through their interactions.Here,we investigated the mechanisms of interactions between the TTR tetramer and various Aβspecies,including two monomers with different morphologies and four oligomers with different molecular weights,by employing molecular dynamics simulations.From these results,we propose a clear interaction scenario:upon AβO binding,the dimer-dimer distance of TTR increases and the binding energy decreases,indicating an unfavorable effect on the TTR stability.Moreover,the larger the molecular weight(MW)of AβO,the greater the effect of interaction between the TTR tetramer and Aβoligomer,and consequently the worse the TTR stability.In turn,Aβ–Aβintermolecular distances in AβO grow and the hydrophobic solvent-accessible surface area(SASA)increases,whereas the number of intermolecular hydrogen bonds decreases,indicating AβO disaggregation induced by the TTR binding.Moreover,a trend is observed for the disaggregation to increase as the MW of the AβO species increases.Finally,we reveal that conformations rich in helical sections rather than the semi-extended conformation are favored upon binding with TTR.Overall,this study provides a comprehensive molecular-level insight to better understand the mechanism and principles of interaction between the TTR tetramer and AβOs.
