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Tritium interactions with irradiation-induced defects in α-Zr are important for understanding getter performance in tritium-producing burnable absorbed rods. Vacancy-type basal loops are prominent in α-Zr irradiated at high dose rates. As they generate substantial tensile strain fields, such loops can trap tritium atoms. For this reason, vacancy-type basal dislocation loops are potentially important for tritium transport, tritium solubility, and tritide precipitation. We perform molecular dynamics simulations of tritium distributions around vacancy-type basal dislocation loops of different sizes, across a temperature range of 700–1200 K. Tritium preferentially segregates to the dislocation core and, to a lesser extent, the stacking fault. Segregation energies are estimated by inverting the tritium concentration distributions by assuming that the Boltzmann distribution adequately describes partitioning between the bulk and core environments. Agreement between molecular dynamics calculated segregation energies and predictions from elasticity theory using the stress field obtained by spatially averaging the atomic virial stresses suggests that elastic interactions dominate the interaction between tritium and basal loops. We also find an attractive tritium–tritium interaction. This attractive interaction can increase the stability of tritium in the dislocation core, resulting in a higher relative tritium concentration as the overall tritium concentration of the system increases. This suggests that vacancy-type basal dislocation loops can increase tritium solubility in irradiated α-Zr and may serve as preferential sites for tritide precipitation. [ABSTRACT FROM AUTHOR]

The joining of the North and South China blocks marks the formation of the united East Asian continent, which is an integral part of Pangea. The amalgamation of these two continental blocks also resulted in the formation of the world‐class ultrahigh pressure orogenic belt, namely the Dabie–Sulu orogenic belt. Figuring out the time of the initial collision between the two continents is critical for resolving questions such as the duration and the geodynamic processes of the orogeny. A Triassic joining time has been suggested by the geochronology of the eclogite facies rocks in this orogenic belt. However, paleomagnetic and paleontological studies suggested a Permian docking time for these continental blocks. In this paper, we present new metamorphic ages of rocks from northern Dabie and the Permo–Triassic intracontinental orogen of South China, which are all closely associated with this continental collisional event. New age dating results, as well as a synthesis of recent studies on metamorphic rocks occurring in southeastern North China and the Cathaysia Block of South China, show that the onset of the collisional orogenesis along the eastern part of the orogenic belt dates back to the Middle Permian (270–252 Ma). Considering these data and other geological records, we provide a new tectonic model for the major continents of East Asia, in which we show that the initial collision between North and South China occurred in the east during the Middle Permian, and then propagated westward. Continental collisions forming mountains and closing seaways in East Asia thus apparently occurred before the end‐Permian mass extinction, suggesting these paleogeographic changes might have also preconditioned and facilitated the end‐Permian biospheric crisis in the region. Plain Language Summary: Orogenic belts are the loci of convergent plate interactions and they provide a window for observing Earth's deep crustal geodynamic processes. Metamorphic rocks in orogenic belts occur with varying metamorphic grades, whose temperatures, pressures, and ages are critical factors for understanding the history of plate interactions. Previous geochronological studies on eclogite facies rocks in the Dabie–Sulu orogenic belt, which is the result of the continental collision between North and South China blocks, have yielded mainly Triassic metamorphic ages. On the other hand, the paleomagnetic and paleontological data support an earlier collisional age during the Permian. This study targeted metamorphic rocks from the southern margin of North China, the northern Dabie orogen, and South China, all of which escaped deep subduction. They all show Permian metamorphic ages (270–252 Ma), which collectively indicate the Permian continental collision between North and South China. This new constraint on the initial continental collision between the two continental blocks is consistent not only with the paleomagnetic and paleontological data but also with the proposal of a diachronous collisional model for the Central China Orogenic belt with a westward younging trend. Key Points: The continental collision between North and South China resulted in the formation of the East Asian continent within PangeaNew geochronological results constraining the orogenesis reveal the onset of collision during the PermianThe Permian collision might have also preconditioned and facilitated the end‐Permian biospheric crisis in the region [ABSTRACT FROM AUTHOR]

Solid-state hydrogen storage materials undergo complex phase transformations whose behavior are collectively determined by thermodynamic (e.g., Gibbs free energy), mechanical (e.g., lattice and elastic constants), and mass transport (e.g., diffusivity) properties. These properties depend on the reaction conditions and evolve continuously during (de)hydrogenation. Thus, they are difficult to measure in experiments. Because of this, past progress to improve solid-state hydrogen storage materials has been prolonged. Using PdHx as a representative example for interstitial metal hydride, we have recently applied molecular dynamics simulations to quantify hydrogen diffusion in the entire reaction space of temperature and composition. Here, we have further applied molecular dynamics simulations to obtain well-converged expressions for lattice constants, Gibbs free energies, and elastic constants of PdHx at various stages of the reaction. Our studies confirm significant dependence of elastic constants on temperature and composition. Specifically, a new dynamic effect of hydrogen diffusion on elastic constants is discovered and discussed. [ABSTRACT FROM AUTHOR]

A Stillinger-Weber potential is computationally very efficient for molecular dynamics simulations. Despite its simple mathematical form, the Stillinger-Weber potential can be easily parameterized to ensure that crystal structures with tetrahedral bond angles (e.g., diamond-cubic, zinc-blende, and wurtzite) are stable and have the lowest energy. As a result, the Stillinger-Weber potential has been widely used to study a variety of semiconductor elements and alloys. When studying an A-B binary system, however, the Stillinger-Weber potential is associated with two major drawbacks. First, it significantly overestimates the elastic constants of elements A and B, limiting its use for systems involving both compounds and elements (e.g., an A/AB multilayer). Second, it prescribes equal energy for zinc-blende and wurtzite crystals, limiting its use for compounds with large stacking fault energies. Here, we utilize the polymorphic potential style recently implemented in LAMMPS to develop a modified Stillinger-Weber potential for InGaN that overcomes these two problems. [ABSTRACT FROM AUTHOR]

We investigate the formation of extended defects during molecular-dynamics (MD) simulations of GaN and InGaN growth on (0001) and (1120) wurtzite-GaN surfaces. The simulated growths are conducted on an atypically large scale by sequentially injecting nearly a million individual vaporphase atoms towards a fixed GaN surface; we apply time-and-position-dependent boundary constraints that vary the ensemble treatments of the vapor-phase, the near-surface solid-phase, and the bulk-like regions of the growing layer. The simulations employ newly optimized Stillinger-Weber In-Ga-N-system potentials, wherein multiple binary and ternary structures are included in the underlying density-functional-theory training sets, allowing improved treatment of In-Ga-related atomic interactions. To examine the effect of growth conditions, we study a matrix of >30 different MD-growth simulations for a range of InxGa1-xN-alloy compositions (0≤x≤0.4) and homologous growth temperatures [0.50≤T/T* m(x)≤0.90], where T* m(x) is the simulated melting point. Growths conducted on polar (0001) GaN substrates exhibit the formation of various extended defects including stacking faults/polymorphism, associated domain boundaries, surface roughness, dislocations, and voids. In contrast, selected growths conducted on semi-polar (1120) GaN, where the wurtzite-phase stacking sequence is revealed at the surface, exhibit the formation of far fewer stacking faults. We discuss variations in the defect formation with the MD growth conditions, and we compare the resulting simulated films to existing experimental observations in InGaN/GaN. While the palette of defects observed by MD closely resembles those observed in the past experiments, further work is needed to achieve truly predictive large-scale simulations of InGaN/GaN crystal growth using MD methodologies. [ABSTRACT FROM AUTHOR]

Molecular dynamics simulations have been used to analyse microstructures of CdTe films grown on {112} surfaces of zinc-blende CdS. Interestingly, CdTe films grow in h331i orientations as opposed to h112i epitaxial orientations. At the CdTe-{331}/CdS-{112} interface, however, there exists an axis that is parallel to the h110i orientation of both CdS and CdTe. It is the direction orthogonal to this h110i that becomes different, being h116i for CdTe and h111i for CdS, respectively. Missing CdTe-{110} planes are found along the h110i axis, suggesting that the misfit strain is released by the conventional misfit dislocation mechanism along this axis. In the orthogonal axis, the misfit strain is found to be more effectively released by the new grain orientation mechanism. Our finding is supported by literature experimental observations of the change of growth direction when Cd0.96Zn0.04Te films are deposited on GaAs. Analyses of energetics clearly demonstrate the cause for the formation of the new orientation, and the insights gained from our studies can help understand the grain structures experimentally observed in lattice mismatched systems. [ABSTRACT FROM AUTHOR]

OBJECTIVE: LncRNA urothelial cancer associated 1 (UCA1) is involved in the development of laryngeal squamous cell carcinoma (LSCC), however, its specific mechanism is not fully clear. PATIENTS AND METHODS: Quantitative reverse transcription-PCR (RT-qPCR) was conducted to determine the expressions of lncRNA-UCA1, miR-185-5p and homeobox A13 (HOXA13) in LSCC tissues and cell lines. Cell Counting Kit-8 assay, colony formation assay, wound healing assay, Transwell and flow cytometry, DIANA-LncBase V2, as well as Starbase, Targetscan, and Dual-Luciferase reporter gene system were conducted to detect and confirm the crosstalk networks among lncRNA-UCA1, miR-185-5p, and HOXA13. RESULTS: The levels of UCA1 and HOXA13 were significantly higher and the expression of miR-185-5p was reduced in LSCC tissues and cell lines. Moreover, miR-185-5p was predicted as a target gene for lncRNA UCA1, while HOXA13 was the target gene for miR-185-5p. UCA1 siRNA inhibited the proliferation and invasion of LSCC cells, moreover, the proliferation and invasion of LSCC cells were suppressed by miR-185-5p mimics but were enhanced by miR-185-5p inhibitor. UCA1 siRNA and overexpressed HOXA13 reversed the promotive effects of miR-185-5p inhibitor and inhibitory effects of miR-185-5p mimics on cell proliferation and metastasis, respectively. CONCLUSIONS: The current findings reveal the important role of lncRNA UCA1/miR-185-5p/HOXA13 regulatory network in LSCC cells, and potentially provide new insights into the pathogenesis of LSCC. [ABSTRACT FROM AUTHOR]

Electronic properties of semiconductor devices are sensitive to defects such as second phase precipitates, grain sizes, and voids. These defects can evolve over time especially under oxidation environments and it is therefore important to understand the resulting aging behavior in order for the reliable applications of devices. In this paper, we propose a kinetic Monte Carlo framework capable of simultaneous simulation of the evolution of second phases, precipitates, grain sizes, and voids in complicated systems involving many species including oxygen. This kinetic Monte Carlo model calculates the energy barriers of various events based directly on the experimental data. As a first step of our model implementation, we incorporate the second phase formation module in the parallel kinetic Monte Carlo codes SPPARKS. Selected aging simulations are performed to examine the formation of second phase precipitates at the eletroplated Au/Bi2Te3 interface under oxygen and oxygen-free environments, and the results are compared with the corresponding experiments. [ABSTRACT FROM AUTHOR]

OBJECTIVE: Nasopharyngeal carcinoma (NPC) is one of the most common malignancies worldwide. In The Cancer Genome Atlas (TCGA) database, the expression level of lncRNA forkhead box P4 antisense RNA 1 (FOXP4-AS1) is higher in NPC samples than in normal samples. PATIENTS AND METHODS: Quantitative Real-time PCR and Western blotting were performed to detect the expression level of RNA and protein. Luciferase reporter assay ran to test the interactions between FOXP4-AS1 and miR-423-5p and STMN1. Subcellular fractionation assay was used to determine the subcellular localization of FOXP4-AS1. The tumor-promotion functions of FOXP4-AS1 were determined by both in vitro and in vivo assays. RESULTS: The expression of FOXP4-AS1 was up-regulated in 80 cases with NPC, and these patients with a poor prognosis. Functionally, high expression of FOXP4-AS1 in NPC was connected with promoted cell proliferation and inhibited apoptosis. Moreover, FOXP4-AS1 is located in the cytoplasm of CNE1 (NPC cell lines). Mechanistically, FOXP4-AS1 up-regulated STMN1 on post-transcriptional regulation by means of miR-423-5p. CONCLUSIONS: Our present study demonstrated that high expression of FOXP4-AS1 in NPC portended poor outcomes. FOXP4-AS1upregulated STMN1 by interacting with miR-423- 5p as a competing endogenous RNA (ceRNA) to promote NPC progression. [ABSTRACT FROM AUTHOR]

Mud ivory whelk (Babylonia lutosa) is one of the most economically important seawater mollusks in China. However, currently, there is no report on the molecular markers related to the growth of Babylonia lutosa, which hinders the its genetic breeding with dominant growth traits. The present study was the first to sequence the transcriptomes of B. lutosa, and then searched for EST-SSR in the growth-related genes. Wild B. lutosa samples were collected from the Lianjiang River, Fujian Province of China. The RNA of gastropods and hepatopancreas tissues from three B. lutosa were measured and mixed, and sequenced by Illumina HiSeq sequencer. A total of 24,829,460 reads containing 5,015,236,064 bp were obtained through sequencing. Eight growth-related genes (TBC-1-A, TBC-1-2B, FGFR-1, GFRBP2, GFR-15, FGFR-1-A, SMAD6, and TGFβR-1) containing EST-SSR sequences were detected in the B. lutosa transcriptomes. Our results would provide theoretical basis for B. lutosa breeding based on growth-related EST-SSRs. [ABSTRACT FROM AUTHOR]