Many properties of planets such as their interior structure and thermal evolution depend on the high-pressure properties of their constituent materials. This paper reviews how crystal structure prediction methodology ...Many properties of planets such as their interior structure and thermal evolution depend on the high-pressure properties of their constituent materials. This paper reviews how crystal structure prediction methodology can help shed light on the transformations materials undergo at the extreme conditions inside planets. The discussion focuses on three areas:(i) the propensity of iron to form compounds with volatile elements at planetary core conditions(important to understand the chemical makeup of Earth's inner core),(ii) the chemistry of mixtures of planetary ices(relevant for the mantle regions of giant icy planets), and(iii) examples of mantle minerals. In all cases the abilities and current limitations of crystal structure prediction are discussed across a range of example studies.展开更多
Talc is a layered hydrous silicate mineral that plays a vital role in transporting water into Earth’s interior and is crucial for explaining geophysical observations in subduction zone settings.In this study,we explo...Talc is a layered hydrous silicate mineral that plays a vital role in transporting water into Earth’s interior and is crucial for explaining geophysical observations in subduction zone settings.In this study,we explored the structure,equation of state,and elasticity of both triclinic and monoclinic talc under high pressures up to 18 GPa using first principles simulations based on density functional theory corrected for dispersive forces.Our results indicate that principal components of the full elastic constant tensor C_(11) and C_(22),shear components C_(66),and several off-diagonal components show anomalous pressure dependence.This non-monotonic pressure dependence of elastic constant components is likely related to the structural changes and is often manifested in a polytypic transition from a low-pressure polytype talc-I to a high-pressure polytype talc-Ⅱ.The polytypic transition of talc occurs at pressures within its thermodynamic stability.However,the bulk and shear elastic moduli show no anomalous softening.Our study also shows that talc has low velocity,extremely high anisotropy,and anomalously high V_(P)/V_(S) ratio,thus making it a potential candidate mineral phase that could readily explain unusually high V_(P)/V_(S) ratio and large shear wave splitting delays as observed from seismological studies in many subduction systems.展开更多
Accumulation of DNA damage and genomic instability are believed to have crucial effects in neurodegenerative conditions such as Alzheimer’s disease,Parkinson’s disease,Huntington’s disease,premature aging diseases ...Accumulation of DNA damage and genomic instability are believed to have crucial effects in neurodegenerative conditions such as Alzheimer’s disease,Parkinson’s disease,Huntington’s disease,premature aging diseases as well as amyotrophic lateral sclerosis(ALS)and frontotemporal dementia(FTD).Until recently these studies were largely correlative in nature,though raising the possibility that defects in the DNA damage response(DDR)underlie neurodegenerative diseases.展开更多
Amyotrophic lateral sclerosis (ALS) is one of the most dreadful neurodegenerative diseases leading to death within 1-5 years after symptom onset.The majority of ALS cases are sporadic(sALS),while the remaining 5-10%ar...Amyotrophic lateral sclerosis (ALS) is one of the most dreadful neurodegenerative diseases leading to death within 1-5 years after symptom onset.The majority of ALS cases are sporadic(sALS),while the remaining 5-10%are familial(fALS).Genetic discoveries have identified ALScausative mutations in more than 30 genes so far(Chia et al.,2018).Indeed,the four most common mutations observed in ALS genes in Europe are the hexanucleotide expansion repeat in Chromosome9 Open Reading Frame 72 (C9ORF72),Cu-Zn superoxide dismutase 1 (SOD1),tra nsactive response DNA Binding protein 43kDa (TARDBP)and fused in sa rcoma (FUS).展开更多
The amount of sulfur in SO2 discharged in volcanic eruptions exceeds that available for degassing from the erupted magma.This geological conun drum,known as the"sulfur excess",has been the subject of conside...The amount of sulfur in SO2 discharged in volcanic eruptions exceeds that available for degassing from the erupted magma.This geological conun drum,known as the"sulfur excess",has been the subject of considerable interests but remains an open question.Here,in a systematic computational investigation of sulfur-oxygen compounds under pressure,a hitherto unknown S_(3)O_(4) compound containing a mixture of sulfur oxidation states+11 and+IV is predicted to be stable at pressures above 79 GPa.We speculate that S_(3)O_(4) may be produced via redox reactions involving subducted S-bearing minerals(e.g.,sulfates and sulfides)with iron and goethite under high-pressure conditions of the deep lower mantle,decomposing to SO2 and S at shallow depths.S_(3)O_(4) may thus be a key intermediate in promoting decomposition of sulfates to release SO2,offering an alter native source of excess sulfur released during explosive eruptions.These findings provide a possible resolution of the"excess sulfur degassing"paradox and a viable mechanism for the exchange of S between Earth's surface and the lower mantle in the deep sulfur cycle.展开更多
基金A Research Fellowship for International Young Scientists by the National Natural Science Foundation (NNSF) on “In-silico studies of planetary materials” Computing resources provided by the UK national high performance computing service, ARCHER, and the UK Materials and Molecular Modelling Hub, which is partially funded by EPSRC (EP/P020194)for which access was obtained via the UKCP consortium funded by EPSRC grant No. EP/P022561/1
文摘Many properties of planets such as their interior structure and thermal evolution depend on the high-pressure properties of their constituent materials. This paper reviews how crystal structure prediction methodology can help shed light on the transformations materials undergo at the extreme conditions inside planets. The discussion focuses on three areas:(i) the propensity of iron to form compounds with volatile elements at planetary core conditions(important to understand the chemical makeup of Earth's inner core),(ii) the chemistry of mixtures of planetary ices(relevant for the mantle regions of giant icy planets), and(iii) examples of mantle minerals. In all cases the abilities and current limitations of crystal structure prediction are discussed across a range of example studies.
基金supported by the US National Science Foundation grant EAR 1763215 and EAR 1753125XSEDE facilities(GEO170003)+4 种基金the High-Performance Computing,Research Computing Center,Florida State Universitythe UK’s National Supercomputer Service through the UK CarParrinello Consortium(EPSRC Grant No.EP/P022561/1)and project ID d56"Planetary Interiors"funding from the INSU-CNRSthe French Government Laboratory of Excellence initiative n°ANR-10-LABX-0006,the Région Auvergnethe European Regional Development Fund(Cler Volc contribution number 530).
文摘Talc is a layered hydrous silicate mineral that plays a vital role in transporting water into Earth’s interior and is crucial for explaining geophysical observations in subduction zone settings.In this study,we explored the structure,equation of state,and elasticity of both triclinic and monoclinic talc under high pressures up to 18 GPa using first principles simulations based on density functional theory corrected for dispersive forces.Our results indicate that principal components of the full elastic constant tensor C_(11) and C_(22),shear components C_(66),and several off-diagonal components show anomalous pressure dependence.This non-monotonic pressure dependence of elastic constant components is likely related to the structural changes and is often manifested in a polytypic transition from a low-pressure polytype talc-I to a high-pressure polytype talc-Ⅱ.The polytypic transition of talc occurs at pressures within its thermodynamic stability.However,the bulk and shear elastic moduli show no anomalous softening.Our study also shows that talc has low velocity,extremely high anisotropy,and anomalously high V_(P)/V_(S) ratio,thus making it a potential candidate mineral phase that could readily explain unusually high V_(P)/V_(S) ratio and large shear wave splitting delays as observed from seismological studies in many subduction systems.
基金AH was supported by the Hermann and Lilly Schilling-Stiftung für medizinische Forschung im Stifterverband.
文摘Accumulation of DNA damage and genomic instability are believed to have crucial effects in neurodegenerative conditions such as Alzheimer’s disease,Parkinson’s disease,Huntington’s disease,premature aging diseases as well as amyotrophic lateral sclerosis(ALS)and frontotemporal dementia(FTD).Until recently these studies were largely correlative in nature,though raising the possibility that defects in the DNA damage response(DDR)underlie neurodegenerative diseases.
基金Hermann und Lilly Schilling Stiftung für Medizinische Forschung im Stifterverbond (to AH)。
文摘Amyotrophic lateral sclerosis (ALS) is one of the most dreadful neurodegenerative diseases leading to death within 1-5 years after symptom onset.The majority of ALS cases are sporadic(sALS),while the remaining 5-10%are familial(fALS).Genetic discoveries have identified ALScausative mutations in more than 30 genes so far(Chia et al.,2018).Indeed,the four most common mutations observed in ALS genes in Europe are the hexanucleotide expansion repeat in Chromosome9 Open Reading Frame 72 (C9ORF72),Cu-Zn superoxide dismutase 1 (SOD1),tra nsactive response DNA Binding protein 43kDa (TARDBP)and fused in sa rcoma (FUS).
基金supported by the National Natural Science Foundation of China(12034009,91961204,11774127,12174142,11404128,11822404,52090024 and 11974134)the Program for Science and Technology Innovative Research Team of Jilin University。
文摘The amount of sulfur in SO2 discharged in volcanic eruptions exceeds that available for degassing from the erupted magma.This geological conun drum,known as the"sulfur excess",has been the subject of considerable interests but remains an open question.Here,in a systematic computational investigation of sulfur-oxygen compounds under pressure,a hitherto unknown S_(3)O_(4) compound containing a mixture of sulfur oxidation states+11 and+IV is predicted to be stable at pressures above 79 GPa.We speculate that S_(3)O_(4) may be produced via redox reactions involving subducted S-bearing minerals(e.g.,sulfates and sulfides)with iron and goethite under high-pressure conditions of the deep lower mantle,decomposing to SO2 and S at shallow depths.S_(3)O_(4) may thus be a key intermediate in promoting decomposition of sulfates to release SO2,offering an alter native source of excess sulfur released during explosive eruptions.These findings provide a possible resolution of the"excess sulfur degassing"paradox and a viable mechanism for the exchange of S between Earth's surface and the lower mantle in the deep sulfur cycle.
