222 research outputs found

    Momentum-resolved Raman spectroscopy of non-interacting ultracold Fermi gas

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    We report the experiment on probing the one-body spectral function in a trapped non-interacting 40^{40}K Fermi gas by means of the momentum-resolved Raman spectroscopy The experimental result is in good agreement with the expected quadratic dispersion in the non-interacting regime. Through the comparison with the radio-frequency spectrum, we found that the Raman spectrum shows some new characteristics.Comment: 4 pages, 2 figures, appear in Phys. Rev.

    Refugial isolation and range expansions drive the genetic structure of \u3cem\u3eOxyria sinensis\u3c/em\u3e (Polygonaceae) in the Himalaya-Hengduan Mountains

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    The formation of the Mekong-Salween Divide and climatic oscillations in Pleistocene were the main drivers for the contemporary diversity and genetic structure of plants in the Himalaya-Hengduan Mountains (HHM). To identify the relative roles of the two historical events in shaping population history of plants in HHM, we investigated the phylogeographic pattern of Oxyria sinensis, a perennial plant endemic to the HHM. Sixteen chloroplast haplotypes were identified and were clustered into three phylogenetic clades. The age of the major clades was estimated to be in the Pleistocene, falling into several Pleistocene glacial stages and postdating the formation of the Mekong-Salween Divide. Range expansions occurred at least twice in the early and middle Pleistocene, but the spatial genetic distribution rarely changed since the Last Glacial Maximum. Our results suggest that temporary mountain glaciers may act as barriers in promoting the lineage divergence in O. sinensis and that subsequential range expansions and secondary contacts might reshape the genetic distribution in geography and blur the boundary of population differentiation created in the earlier glacial stages. This study demonstrates that Pleistocene climatic change and mountain glaciers, rather than the Mekong-Salween Divide, play the primary role in shaping the spatial genetic structure of O. sinensis

    Bridging multiscale interfaces for developing ionically conductive high-voltage iron sulfate-containing sodium-based battery positive electrodes

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    Non-aqueous sodium-ion batteries (SiBs) are a viable electrochemical energy storage system for grid storage. However, the practical development of SiBs is hindered mainly by the sluggish kinetics and interfacial instability of positive-electrode active materials, such as polyanion-type iron-based sulfates, at high voltage. Here, to circumvent these issues, we proposed the multiscale interface engineering of Na2.26_{2.26}Fe1.87_{1.87}(SO4_4)3_3, where bulk heterostructure and exposed crystal plane were tuned to improve the Na-ion storage performance. Physicochemical characterizations and theoretical calculations suggested that the heterostructure of Na6_6Fe(SO4_4)4_4 phase facilitated ionic kinetics by densifying Na-ion migration channels and lowering energy barriers. The (11-2) plane of Na2.26_{2.26}Fe1.87_{1.87}(SO4_4)3_3 promoted the adsorption of the electrolyte solution ClO4− anions and fluoroethylene carbonate molecules, which formed an inorganic-rich Na-ion conductive interphase at the positive electrode. When tested in combination with a presodiated FeS/carbon-based negative electrode in laboratory- scale single-layer pouch cell configuration, the Na2.26_{2.26}Fe1.87_{1.87}(SO4_4)3_3-based positive electrode enables an initial discharge capacity of about 83.9 mAh g1^{−1}, an average cell discharge voltage of 2.35 V and a specific capacity retention of around 97% after 40 cycles at 24 mA g1^{−1} and 25 °C

    Clusterin confers gmcitabine resistance in pancreatic cancer

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    <p>Abstract</p> <p>Objective</p> <p>To measure clusterin expression in pancreatic cancer tissues and cell lines and to evaluate whether clusterin confers resistance to gmcitabine in pancreatic cancer cells.</p> <p>Methods</p> <p>Immunohistochemistry for clusterin was performed on 50 primary pancreatic cancer tissues and 25 matched backgrounds, and clusterin expression in 5 pancreatic cancer cell lines was quantified by Western blot and PT-PCR. The correlation between clusterin expression level and gmcitabine IC50 in pancreatic cancer cell lines was evaluated. The effect of an antisense oligonucleotide (ASO) against clusterin(OGX-011) on gmcitabine resistance was evaluated by MTT assays. Xenograft model was used to demonstrate tumor growth.</p> <p>Results</p> <p>Pancreatic cancer tissues expressed significantly higher levels of clusterin than did normal pancreatic tissues (<it>P </it>< 0.01). Clusterin expression levels were correlated with gmcitabine resistance in pancreatic cancer cell lines, and OGX-011 significantly decreased BxPc-3 cells resistance to gmcitabine (<it>P </it>< 0.01). <it>In vivo </it>systemic administration of AS clusterin and gmcitabine significantly decreased the s.c. BxPC-3 tumor volume compared with mismatch control ODN plus gmcitabine.</p> <p>Conclusion</p> <p>Our finding that clusterin expression was significantly higher in pancreatic cancer than in normal pancreatic tissues suggests that clusterin may confer gmcitabine resistance in pancreatic cancer cells.</p
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