ORCID Profile
0000-0002-9293-5430
Current Organisation
Chongqing University
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Publisher: Elsevier BV
Date: 2020
Publisher: Springer Science and Business Media LLC
Date: 03-05-2016
DOI: 10.1038/SREP25427
Abstract: The shear-induced coupled grain boundary motion plays an important role in the deformation of nanocrystalline (NC) materials. It has been known that the atomic structure of the grain boundary (GB) is not necessarily unique for a given set of misorientation and inclination of the boundary plane. However, the effect of the structural multiplicity of the GB on its coupled motion has not been reported. In the present study we investigated the structural multiplicity of the symmetric tilt Σ5(310) boundary in aluminium and its influence on the GB behaviour at a temperature range of 300 K–600 K using molecular dynamic simulations. Two starting atomic configurations were adopted in the simulations which resulted in three different GB structures at different temperatures. Under the applied shear deformation each GB structure exhibited its unique GB behaviour. A dual GB behaviour, namely the transformation of one GB behaviour to another during deformation, was observed for the second starting configuration at a temperature of 500 K. The atomistic mechanisms responsible for these behaviour were analysed in detail. The result of this study implicates a strong relationship between GB structures and their behaviour and provides a further information of the grain boundary mediated plasticity in nanocrystalline materials.
Publisher: Elsevier BV
Date: 11-2020
Publisher: Springer Science and Business Media LLC
Date: 09-06-2022
DOI: 10.1038/S41388-022-02377-9
Abstract: The consistency of the associations between gastric mucosal microbiome and gastric cancer across studies remained unexamined. We aimed to identify universal microbial signatures in gastric carcinogenesis through a meta-analysis of gastric microbiome from multiple studies. Compositional and ecological profiles of gastric microbes across stages of gastric carcinogenesis were significantly altered. Meta-analysis revealed that opportunistic pathobionts Fusobacterium , Parvimonas , Veillonella , Prevotella and Peptostreptococcus were enriched in GC, while commensals Bifidobacterium , Bacillus and Blautia were depleted in comparison to SG. The co-occurring correlation strengths of GC-enriched bacteria were increased along disease progression while those of GC-depleted bacteria were decreased. Eight bacterial taxa, including Veillonella , Dialister , Granulicatella , Herbaspirillum , Comamonas , Chryseobacterium , Shewanella and Helicobacter , were newly identified by this study as universal biomarkers for robustly discriminating GC from SG, with an area under the curve (AUC) of 0.85. Moreover, H. pylori -positive s les exhibited reduced microbial ersity, altered microbiota community and weaker interactions among gastric microbes. Our meta-analysis demonstrated comprehensive and generalizable gastric mucosa microbial features associated with histological stages of gastric carcinogenesis, including GC associated bacteria, diagnostic biomarkers, bacterial network alteration and H. pylori influence.
Publisher: Elsevier BV
Date: 07-2019
Publisher: Hindawi Limited
Date: 2017
DOI: 10.1155/2017/8296458
Abstract: Grain boundary (GB) can serve as an efficient sink for radiation-induced defects, and therefore nanocrystalline materials containing a large fraction of grain boundaries have been shown to have improved radiation resistance compared with their polycrystalline counterparts. However, the mechanical properties of grain boundaries containing radiation-induced defects such as interstitials and vacancies are not well understood. In this study, we carried out molecular dynamics simulations with embedded-atom method (EAM) potential to investigate the interaction of Σ5(210)/[ 001 ] symmetric tilt GB in Cu with various amounts of self-interstitial atoms. The mechanical properties of the grain boundary were evaluated using a bicrystal model by applying shear deformation and uniaxial tension. Simulation results showed that GB migration and GB sliding were observed under shear deformation depending on the number of interstitial atoms that segregated on the boundary plane. Under uniaxial tension, the grain boundary became a weak place after absorbing self-interstitial atoms where dislocations and cracks were prone to nucleate.
Publisher: Elsevier BV
Date: 10-2023
Publisher: Wiley
Date: 09-2018
Publisher: IOP Publishing
Date: 19-08-2016
Publisher: Elsevier BV
Date: 09-2020
Publisher: Elsevier BV
Date: 07-2021
Publisher: Elsevier BV
Date: 03-2016
Publisher: Elsevier BV
Date: 10-2016
Publisher: Wiley
Date: 11-07-2018
Publisher: IOP Publishing
Date: 09-2014
Publisher: Elsevier BV
Date: 04-2021
Publisher: Elsevier BV
Date: 02-2018
Publisher: Springer Science and Business Media LLC
Date: 20-12-2022
DOI: 10.1038/S41388-022-02569-3
Abstract: Appendectomy impacts the homeostasis of gut microbiome in patients. We aimed to study the role of appendectomy in colorectal cancer (CRC) risk through causing gut microbial dysbiosis. Population-based longitudinal study (cohort 1, n = 129,155) showed a 73.0% increase in CRC risk among appendectomy cases throughout 20 years follow-up (Adjusted sub-distribution hazard ratio (SHR) 1.73, 95% CI 1.49–2.01, P 0.001). Shotgun metagenomic sequencing was performed on fecal s les from cohort 2 ( n = 314). Gut microbial dysbiosis in appendectomy subjects was observed with significant enrichment of 7 CRC-promoting bacteria ( Bacteroides vulgatus, Bacteroides fragilis, Veillonella dispar, Prevotella ruminicola, Prevotella fucsa, Prevotella dentalis, Prevotella denticola ) and depletion of 5 beneficial commensals ( Blautia sp YL58, Enterococcus hirae, Lachnospiraceae bacterium Choco86, Collinsella aerofaciens, Blautia sp SC05B48 ). Microbial network analysis showed increased correlation strengths among enriched bacteria and their enriched oncogenic pathways in appendectomy subjects compared to controls. Of which, B. fragilis was the centrality in the network of the enriched bacteria. We further confirmed that appendectomy promoted colorectal tumorigenesis in mice by causing gut microbial dysbiosis and impaired intestinal barrier function. Collectively, this study revealed appendectomy-induced microbial dysbiosis characterized by enriched CRC-promoting bacteria and depleted beneficial commensals, signifying that the gut microbiome may play a crucial role in CRC development induced by appendectomy.
Publisher: Elsevier BV
Date: 07-2023
Publisher: Trans Tech Publications, Ltd.
Date: 07-2016
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMM.846.288
Abstract: A finite-temperature analysis of a multiscale model, which couples finite element and molecular dynamics, is presented in this paper. The model is evaluated by the patch test and demonstrates its capacity. Then, the multiscale scheme is used to study 3D nanoscale contacts. The linear relationship between the contact area ratio and load is observed at small loads, but the temperature effect is small. However, the change in the root mean square (RMS) of heights depends on the temperature at high loads.
Publisher: Elsevier BV
Date: 05-2022
Publisher: Trans Tech Publications, Ltd.
Date: 07-2013
DOI: 10.4028/WWW.SCIENTIFIC.NET/JNANOR.23.50
Abstract: A large-scale molecular dynamics simulation was used to investigate the propagation of cracks in three dimensional s les of nanocrystalline copper, with average grain sizes ranging from 5.34 to 14.8 nm and temperatures ranging from 1K to 500 K. It was shown that intragranular fracture can proceed inside the grain at low temperature, and plastic deformation around the tip of the crack is accommodated by dislocation nucleation/emission indeed, both fully extended dislocation and deformation twinning were visible around the tip of the crack during fracture. In addition, due to a higher concentration of stress in front of the crack at a relative lower temperature, it was found that twinning deformation is easier to nucleate from the tip of the crack. These results also showed that the decreasing grain size below a critical value exhibits a reverse Hall-Petch relationship due to the enhancing grain boundary mediation, and high temperature is better for propagating ductile cracks.
Publisher: Elsevier BV
Date: 06-2016
Publisher: Elsevier BV
Date: 07-2017
Publisher: IOP Publishing
Date: 08-2015
Publisher: Wiley
Date: 04-2021
DOI: 10.1111/JGH.15501
Abstract: Gut microbiota has been shown to associate with the development of gastrointestinal diseases. In the last decade, development in whole metagenome sequencing and 16S rRNA sequencing technology has dramatically accelerated the gut microbiome's research and revealed its association with gastrointestinal disorders. Because of high dimensionality and complexity's intrinsic data characteristics, traditional bioinformatical methods could only explain the most significant changes with limited prediction accuracy. In contrast, machine learning is the application of artificial intelligence that provides the computational systems to automatically learn and improve from experience (training cohort) without being explicitly programmed. It is thus capable of unwiring high dimensionality and complicated correlational hitches. With modern computation power, machine learning is widely utilized to analyze microorganisms related to disease onset and other clinical features. It could help explore and identify novel biomarkers or improve the accuracy rate of disease diagnostic. This review summarized the most recent research that utilized machine learning to reveal the role of gut microbiota in intestinal disorders.
Publisher: Elsevier BV
Date: 08-2015
Publisher: MDPI AG
Date: 06-06-2021
DOI: 10.3390/MET11060922
Abstract: High-entropy alloys (HEAs) with multiple constituent elements have been extensively studied in the past 20 years, due to their promising engineering application. Previous experimental and computational studies of HEAs focused mainly on equiatomic or near equiatomic HEAs. However, there is probably far more treasure in those non-equiatomic HEAs with carefully designed composition. In this study, the molecular dynamics (MD) simulation combined with machine learning (ML) methods was used to predict the mechanical properties of non-equiatomic CuFeNiCrCo HEAs. A database was established based on a tensile test of 900 HEA single-crystal s les by MD simulation. Eight ML models were investigated and compared for the binary classification learning tasks, ranging from shallow models to deep models. It was found that the kernel-based extreme learning machine (KELM) model outperformed others for the prediction of yield stress and Young’s modulus. The accuracy of the KELM model was further verified by the large-sized polycrystal HEA s les. The results show that computational simulation combined with ML methods is an efficient way to predict the mechanical performance of HEAs, which provides new ideas for accelerating the development of novel alloy materials for engineering applications.
Publisher: Springer Science and Business Media LLC
Date: 08-2014
DOI: 10.1038/SREP05919
Publisher: IOP Publishing
Date: 03-03-2015
Publisher: Elsevier BV
Date: 10-2017
Publisher: Elsevier BV
Date: 11-2015
Publisher: IOP Publishing
Date: 23-02-2018
Publisher: Wiley
Date: 10-10-2017
Publisher: Elsevier BV
Date: 11-2022
Publisher: Elsevier BV
Date: 09-2018
Publisher: Elsevier BV
Date: 10-2022
DOI: 10.1053/J.GASTRO.2022.06.038
Abstract: The enteric mycobiota is a major component of the human gut microbiota, but its role in colorectal cancer (CRC) remains largely elusive. We conducted a meta-analysis to uncover the contribution of the fungal mycobiota to CRC. We retrieved fecal metagenomic data sets from 7 previous publications and established an additional in-house cohort, totaling 1329 metagenomes (454 with CRC, 350 with adenoma, and 525 healthy in iduals). Mycobiota composition and microbial interactions were analyzed. Candidate CRC-enriched fungal species (Aspergillus rambellii) was functionally validated in vitro and in vivo. Multicohort analysis revealed that the enteric mycobiota was altered in CRC. We identified fungi that were associated with patients with CRC or adenoma from multiple cohorts. Signature CRC-associated fungi included 6 enriched (A rambellii, Cordyceps sp. RAO-2017, Erysiphe pulchra, Moniliophthora perniciosa, Sphaerulina musiva, and Phytophthora capsici) and 1 depleted species (A kawachii). Co-occurrent interactions among CRC-enriched fungi became stronger in CRC compared with adenoma and healthy in iduals. Moreover, we reported the transkingdom interactions between enteric fungi and bacteria in CRC progression, of which A rambellii was closely associated with CRC-enriched bacteria Fusobacterium nucleatum. A rambellii promoted CRC cell growth in vitro and tumor growth in xenograft mice. We further identified that combined fungal and bacterial biomarkers were more accurate than panels with pure bacterial species to discriminate patients with CRC from healthy in iduals (the area under the curve relative change increased by 1.44%-10.60%). This study reveals enteric mycobiota signatures and pathogenic fungi in stages of colorectal tumorigenesis. Fecal fungi can be used, in addition to bacteria, for noninvasive diagnosis of patients with CRC.
Publisher: Elsevier BV
Date: 2017
Publisher: IOP Publishing
Date: 31-01-2014
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C4NR07496C
Abstract: The dissociated stacking fault from the grain boundary plane can increase ductility while retaining the high strength of the Cu bicrystal model under shear deformation.
Publisher: Elsevier BV
Date: 05-2015
Publisher: MDPI AG
Date: 08-09-2022
DOI: 10.3390/MET12091491
Abstract: The tungsten components in nuclear fusion reactors need to withstand the radiation cascade damage caused by the neutron bombardment of high temperature and high throughput fusion reaction during service. These damages are mainly present as a high concentration of point defects and clusters, which lead to a series of problems such as irradiation-hardening and decreased thermal conductivity of materials. In this study, molecular dynamics simulations are carried out to study the dynamic interaction between grain boundaries and the void in tungsten at high temperatures (T 2500 K). Different interatomic potentials of W were tested, and the most appropriate one was selected by the thermodynamic and kinetic properties of W. Simulation results show that the dynamic migration of grain boundary can absorb the void, but the absorption efficiency of grain boundaries is sensitive to their structural characteristics, where the high-angle GBs are more absorptive to the void than the low-angle GBs. It is found that the void absorption cannot be completely attributed to the thermal diffusion mechanism during the GB-void interaction the dynamic migration of high-angle GBs can significantly accelerate the void absorption. This study reveals a GB migration-induced self-healing mechanism of W at high temperatures.
Publisher: Elsevier BV
Date: 05-2020
Publisher: Elsevier BV
Date: 12-2022
Publisher: IOP Publishing
Date: 05-2017
Publisher: Elsevier BV
Date: 2018
Publisher: Elsevier BV
Date: 2019
Publisher: MDPI AG
Date: 22-11-2021
DOI: 10.3390/MET11111875
Abstract: Metallic materials produce various structural defects in the radiation environment, resulting in serious degradation of material properties. An important way to improve the radiation-resistant ability of materials is to give the microstructure of materials a self-healing ability, to eliminate the structural defects. The research and development of new radiation-resistant materials with excellent self-healing ability, based on defects control, is one of the hot topics in materials science. Compared with conventional coarse-grained materials, nanocrystalline metals with a high density of grain boundary (GB) show a higher ability to resist radiation damage. However, the mechanism of GB’s absorption of structural defects under radiation is still unclear, and how to take advantage of the GB properties to improve the radiation resistance of metallic materials remains to be further investigated. In recent decades, atomistic simulation has been widely used to study the radiation responses of different metals and their underlying mechanisms. This paper briefly reviews the progress in studying radiation resistance mechanisms of nanocrystalline metals by employing computational simulation at the atomic scale.
Publisher: MDPI AG
Date: 15-06-2023
DOI: 10.3390/MA16124414
Abstract: Tungsten (W) can be used in plasma-facing components in a fusion reactor because of its excellent radiation resistance. Some studies have found that nanocrystalline metals with a high density of grain boundary show a higher ability to resist radiation damage compared to conventional coarse-grained materials. However, the interaction mechanism between grain boundary and defect is still unclear. In the present study, molecular dynamics simulations were carried out to explore the difference of defect evolution in single-crystal and bicrystal W, while the effects of temperature and the energy of the primary knocked atom (PKA) were taken into account. The irradiation process was simulated at the temperature range of 300 to 1500 K, and the PKA energy varied from 1 to 15 keV. The results show that the generation of defects is more sensitive to the energy of PKA than temperature the number of defects increases at the thermal spike stage with the increase of the PKA energy, but the correlation with temperature is not strong. The presence of the grain boundary prevented the recombination of interstitial atoms and vacancies during the collision cascades, and the vacancies were more likely to form large clusters than interstitial atoms in the bicrystal models. This can be ascribed to the strong segregation tendency of the interstitial atoms to grain boundaries. The simulations provide useful information for understanding the role of grain boundaries in the evolution of irradiated structural defects.
Publisher: Elsevier BV
Date: 07-2019
Publisher: MDPI AG
Date: 29-06-2022
DOI: 10.3390/MA15134589
Abstract: Although hydrogen embrittlement (HE) behavior has been extensively studied in bulk materials, little is known about H-related deformation and the fracture of nanograined materials. In this study, H segregation and HE mechanisms of nanograined Fe with different grain sizes are unveiled, following the employment of classical molecular dynamics simulations. The H segregation ratio increased, but the local H concentration at the grain boundaries (GBs) decreased with decreases in the grain size at a given bulk H concentration. The results demonstrate that H atoms increased the yield stress of nanograined models irrespective of the grain size. Furthermore, it is revealed that brittle fractures were inhibited, and the resistance to HE increased as the grain size decreased, due to the fact that the small-grain models had a lower local H concentration at the GBs and an enhanced GB-mediated intergranular deformation. These results are a clear indication of the utility of grain refinement to resist H-induced brittle failure.
Publisher: Elsevier BV
Date: 10-2023
Publisher: Elsevier BV
Date: 08-2023
Publisher: Elsevier BV
Date: 12-2021
No related grants have been discovered for Liang Zhang.