| 1. |
- Dai, Ruihan, et al.
(författare)
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Electron crystallography reveals atomic structure of metal-organic nanoplate with Hf12(µ3-O)8(µ3-OH)8(µ2-OH)6 secondary building unit
- 2017
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Ingår i: Inorganic Chemistry. - : American Chemical Society (ACS). - 0020-1669 .- 1520-510X. ; 56:14, s. 8128-8134
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Tidskriftsartikel (refereegranskat)abstract
- Nanoscale metal–organic frameworks (nMOFs) have shown tremendous potential in cancer therapy and biomedical imaging. However, their small dimensions present a significant challenge in structure determination by single-crystal X-ray crystallography. We report here the structural determination of nMOFs by rotation electron diffraction (RED). Two isostructural Zr- and Hf-based nMOFs with linear biphenyldicarboxylate (BPDC) or bipyridinedicarboxylate (BPYDC) linkers are stable under intense electron beams to allow the collection of high-quality RED data, which reveal a MOF structure with M12(μ3-O)8(μ3-OH)8(μ2-OH)6 (M = Zr, Hf) secondary building units (SBUs). The nMOF structures differ significantly from their UiO bulk counterparts with M6(μ3-O)4(μ3-OH)4 SBUs and provide the foundation for clarifying the structures of a series of previously reported nMOFs with significant potential in cancer therapy and biological imaging. Our work clearly demonstrates the power of RED in determining nMOF structures and elucidating the formation mechanism of distinct nMOF morphologies.
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| 2. |
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| 3. |
- Liu, Junzhi, et al.
(författare)
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A dataset of lake-catchment characteristics for the Tibetan Plateau
- 2022
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Ingår i: Earth System Science Data. - : Copernicus GmbH. - 1866-3508 .- 1866-3516. ; 14:8, s. 3791-3805
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Tidskriftsartikel (refereegranskat)abstract
- The management and conservation of lakes should be conducted in the context of catchments because lakes collect water and materials from their upstream catchments. Thus, the datasets of catchment-level characteristics are essential for limnology studies. Lakes are widely spread on the Tibetan Plateau (TP), with a total lake area exceeding 50000km2, accounting for more than half of the total lake area in China. However, there has been no dataset of lake-catchment characteristics in this region to date. This study constructed the first dataset of lake-catchment characteristics for 1525 lakes with areas from 0.2 to 4503km2 on the TP. Considering that large lakes block the transport of materials from upstream to downstream, lake catchments are delineated in two ways: the full catchment, which refers to the full upstream-contributing area of each lake, and the inter-lake catchments, which are obtained by excluding the contributing areas of upstream lakes larger than 0.2km2 from the full catchment. There are six categories (i.e., lake body, topography, climate, land cover/use, soil and geology, and anthropogenic activity) and a total of 721 attributes in the dataset. Besides multi-year average attributes, the time series of 16 hydrological and meteorological variables are extracted, which can be used to drive or validate lumped hydrological models and machine learning models for hydrological simulation. The dataset contains fundamental information for analyzing the impact of catchment-level characteristics on lake properties, which on the one hand, can deepen our understanding of the drivers of lake environment change, and on the other hand can be used to predict the water and sediment properties in unsampled lakes based on limited samples. This provides exciting opportunities for lake studies in a spatially explicit context and promotes the development of landscape limnology on the TP. The dataset of lake-catchment characteristics for the Tibetan Plateau (LCC-TP v1.0) is accessible at the National Tibetan Plateau/Third Pole Environment Data Center (10.11888/Terre.tpdc.272026, Liu, 2022).
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| 4. |
- Wang, Ji, et al.
(författare)
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Microstructure investigations of Fe50Mn30Co10Cr10 dual-phase high-entropy alloy under Fe ions irradiation
- 2021
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Ingår i: Journal of Nuclear Materials. - : ELSEVIER. - 0022-3115 .- 1873-4820. ; 552
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Tidskriftsartikel (refereegranskat)abstract
- An Fe50Mn30Co10Cr10 dual-phase high-entropy alloy (DP-HEA) was irradiated at room temperature with 3 MeV Fe ions to a dose of 50 displacement per atom (dpa). Potentials of special elemental designed DP-HEAs with low stacking fault energy (SFE) as promising candidate materials for future nuclear energy systems are evaluated. Transmission electron microscopy (TEM) analysis finds that FCC gamma-gamma, HCP epsilon-epsilon twinning structures and FCC gamma-HCP epsilon co-existed structures of the DP-HEA, which correlate with the combined high strength and high ductility featured by this alloy, remain stable under a displacement damage of 50 dpa. No elemental segregation after irradiation was detected by energy dispersive spectroscopy. The results indicate that TWIP and TRIP mechanisms, owned by many other DP-HEAs, may still work effectively, and the materials still possess the merits of combined high strength and ductility brought by TWIP and TRIP mechanisms under irradiation conditions. Defects free channels (DFCs) and abundant Lomer-Cottrell (L-C) locks are observed in the irradiated samples after tensile deformation. The immobile L-C locks restrict DFCs growth, prevent the pile-up of dislocation along grain boundaries, thus sustaining dislocations in the grain interior. This study provides a new strategy to improve simultaneously the irradiation resistance and mechanical properties of structural materials by introducing the TWIP and TRIP mechanisms. (C) 2021 Elsevier B.V. All rights reserved.
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| 5. |
- Xu, Qin, et al.
(författare)
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Loss of TET reprograms Wnt signaling through impaired demethylation to promote lung cancer development
- 2022
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences (PNAS). - 0027-8424 .- 1091-6490. ; 119:6
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Tidskriftsartikel (refereegranskat)abstract
- Oncogenic imbalance of DNA methylation is well recognized in cancer development. The ten-eleven translocation (TET) family of dioxygenases, which facilitates DNA demethylation, is frequently dysregulated in cancers. How such dysregulation contributes to tumorigenesis remains poorly understood, especially in solid tumors which present infrequent mutational incidence of TET genes. Here, we identify loss-of-function mutations of TET in 7.4% of human lung adenocarcinoma (LUAD), which frequently co-occur with oncogenic KRAS mutations, and this co-occurrence is predictive of poor survival in LUAD patients. Using an autochthonous mouse model of KrasG12D-driven LUAD, we show that individual or combinational loss of Tet genes markedly promotes tumor development. In this Kras-mutant and Tet-deficient model, the premalignant lung epithelium undergoes neoplastic reprogramming of DNA methylation and transcription, with a particular impact on Wnt signaling. Among the Wnt-associated components that undergo reprogramming, multiple canonical Wnt antagonizing genes present impaired expression arising from elevated DNA methylation, triggering aberrant activation of Wnt signaling. These impairments can be largely reversed upon the restoration of TET activity. Correspondingly, genetic depletion of beta-catenin, the transcriptional effector of Wnt signaling, substantially reverts the malignant progression of Tet-deficient LUAD. These findings reveal TET enzymes as critical epigenetic barriers against lung tumorigenesis and highlight the therapeutic vulnerability of TET-mutant lung cancer through targetingWnt signaling.
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