159 research outputs found

    Experimentally Detecting Quantized Zak Phases without Chiral Symmetry in Photonic Lattices

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    Symmetries play a major role in identifying topological phases of matter and in establishing a direct connection between protected edge states and topological bulk invariants via the bulk-boundary correspondence. One-dimensional lattices are deemed to be protected by chiral symmetry, exhibiting quantized Zak phases and protected edge states, but not for all cases. Here, we experimentally realize an extended Su-Schrieffer-Heeger model with broken chiral symmetry by engineering one-dimensional zigzag photonic lattices, where the long-range hopping breaks chiral symmetry but ensures the existence of inversion symmetry. By the averaged mean displacement method, we detect topological invariants directly in the bulk through the continuous-time quantum walk of photons. Our results demonstrate that inversion symmetry protects the quantized Zak phase but edge states can disappear in the topological nontrivial phase, thus breaking the conventional bulk-boundary correspondence. Our photonic lattice provides a useful platform to study the interplay among topological phases, symmetries, and the bulk-boundary correspondence.This research is supported by the National Key R&D Program of China (2019YFA0308700, 2019YFA0706302, 2017YFA0303700), the National Natural Science Foundation of China (NSFC) (11904229, 11761141014, 61734005, 11690033), the Science and Technology Commission of Shanghai Municipality (STCSM) (20JC1416300, 2019SHZDZX01), the Shanghai Municipal Education Commission (SMEC) (2017-01-07-00-02-E00049). X.-M. J. acknowledges additional support from a Shanghai talent program and support from the Zhiyuan Innovative Research Center of Shanghai Jiao Tong University

    Label-free quantitative proteomic analysis of molting-related proteins of Trichinella spiralis intestinal infective larvae

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    International audienceAbstractMolting is a key step for body-size expansion and environmental adaptation of parasitic nematodes, and it is extremely important for Trichinella spiralis growth and development, but the molting mechanism is not fully understood. In this work, label-free LC–MS/MS was used to determine the proteome differences between T. spiralis muscle larvae (ML) at the encapsulated stage and intestinal infective larvae (IIL) at the molting stage. The results showed that a total of 2885 T. spiralis proteins were identified, 323 of which were differentially expressed. These proteins were involved in cuticle structural elements, regulation of cuticle synthesis, remodeling and degradation, and hormonal regulation of molting. These differential proteins were also involved in diverse intracellular pathways, such as fatty acid biosynthesis, arachidonic acid metabolism, and mucin type O-glycan biosynthesis. qPCR results showed that five T. spiralis genes (cuticle collagen 14, putative DOMON domain-containing protein, glutamine synthetase, cathepsin F and NADP-dependent isocitrate dehydrogenase) had significantly higher transcriptional levels in 10 h IIL than ML (P < 0.05), which were similar to their protein expression levels, suggesting that they might be T. spiralis molting-related genes. Identification and characterization of T. spiralis molting-related proteins will be helpful for developing vaccines and new drugs against the early enteral stage of T. spiralis

    The efficacy of mitochondrial targeting antiresistant epirubicin liposomes in treating resistant leukemia in animals

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    Ying Men*, Xiao-Xing Wang*, Ruo-Jing Li, Yan Zhang, Wei Tian, Hong-Juan Yao, Rui-Jun Ju, Xue Ying, Jia Zhou, Nan Li, Liang Zhang, Yang Yu, Wan-Liang LuState Key Laboratory of Natural and Biomimetic Drugs, and School of Pharmaceutical Sciences, Peking University, Beijing, People&amp;#39;s Republic of China*These authors contributed equally to this manuscriptBackground: Multidrug resistance (MDR) of cancers can be circumvented by inducing programmed cell death, which is known as apoptosis. Mitochondria play a crucial role in apoptosis. Mitochondria-specific therapy would provide an efficient strategy for treating resistant cancers.Design and methods: A strategy was proposed here to overcome MDR by designing cancer mitochondria-specific drug-loaded liposomes, namely, antiresistant epirubicin mitosomes, aimed at treating resistant leukemia by targeting mitochondria. Evaluations were performed on human chronic leukemia K562, MDR K562/ADR cells, and female BALB/c nude mice xenografted with MDR K562/ADR cells. The liposomes were characterized through assays of cytotoxicity, mitochondrial targeting, caspase-9 and caspase-3, antitumor activities, and TUNEL (terminal deoxynucleotidyl transferase dUTP nick end labeling) analysis.Results: The average size of antiresistant epirubicin mitosomes was in the range of 105&amp;ndash;115 nm. Antiresistant epirubicin mitosomes were effective in inhibiting proliferation of MDR K562/ADR cells in vitro and selectively accumulated into the mitochondria. Caspase-9 and caspase-3 activity was increased after applying antiresistant epirubicin mitosomes. In xenografted resistant MDR K562/ADR tumor in nude mice, antiresistant tumor effect of antiresistant epirubicin mitosomes was evidently observed. Apoptotic inducing effects by antiresistant epirubicin mitosomes were noticeably evidenced via mitochondrial pathway.Conclusions: Antiresistant epirubicin mitosomes had significant inhibitory effect against resistant leukemia in vitro and in vivo, hence providing a promising strategy for improving therapeutic efficacy in resistant human leukemia.Keywords: mitosomes, mitochondria signaling pathway, nude mic
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