Topological insulators are materials that behave as insulators in the bulk and as conductors at the edge or surface due to the particular configuration of their bulk band dispersion. However, up to ...date possible practical applications of this band topology on materials' bulk properties have remained abstract. Here, we propose and experimentally demonstrate a topological bulk laser. We pattern semiconductor nanodisk arrays to form a photonic crystal cavity showing topological band inversion between its interior and cladding area. In-plane light waves are reflected at topological edges forming an effective cavity feedback for lasing. This band-inversion-induced reflection mechanism induces single-mode lasing with directional vertical emission. Our topological bulk laser works at room temperature and reaches the practical requirements in terms of cavity size, threshold, linewidth, side-mode suppression ratio and directionality for most practical applications according to Institute of Electrical and Electronics Engineers and other industry standards. We believe this bulk topological effect will have applications in near-field spectroscopy, solid-state lighting, free-space optical sensing and communication.
Background and Purpose
Mitochondrial damage and oxidative stress are crucial contributors to the tubular cell injury and death in acute kidney injury. Novel therapeutic strategies targeting ...mitochondria protection and halting the progression of acute kidney injury are urgently needed. Honokiol is a small‐molecule polyphenol that exhibits extraordinary cytoprotective effects, such as anti‐inflammatory and anti‐oxidative. Thus, we investigated whether honokiol could ameliorate cisplatin‐induced acute kidney injury via preventing mitochondrial dysfunction.
Experimental Approach
Acute kidney injury was induced by cisplatin administration. Biochemical and histological analysis were used to determine kidney injury. The effect of honokiol on mitochondrial function and morphology were determined using immunohistochemistry, transmission electron microscopy, immunoblot and immunofluorescence. To investigate the mechanism by which honokiol alters mitochondrial dynamics, remodelling and resistance to apoptosis, we used transfection experiments, immunoblotting, immunoprecipitation and flow cytometry assay.
Key Results
We demonstrated that the prominent mitochondrial fragmentation occurred in experimental models of cisplatin‐induced nephrotoxicity, which was coupled to radical oxygen species (ROS) overproduction, deterioration of mitochondrial function, release of apoptogenic factors and the consequent apoptosis. Honokiol treatment caused notable reno‐protection and attenuated of these cisplatin‐induced changes. Mechanistically, honokiol treatment recovered the expression of SIRT3 and improved AMPK activity in tubular cells exposure to cisplatin, which preserved the Drp1 phosphorylation at Ser637 and blocked its translocation in mitochondria, consequently preventing mitochondrial fragmentation and subsequent cell injury and death.
Conclusion and Implications
Our results indicate that honokiol may protect against cisplatin‐induced acute kidney injury by preserving mitochondrial integrity and function by SIRT3/AMPK‐dependent mitochondrial dynamics remodelling.
Long non-coding RNAs (LncRNAs) have been demonstrated to play crucial role in tumor growth and metastasis for hepatocellular carcinoma (HCC). LncRNA FAL1 has been indicated to promote the progression ...of various cancers. However, the role of lncRNA FAL1 in HCC was poorly understood.
The expression levels of lncRNA FAL1 in HCC tissues and cells were determined by RT-qPCR. The roles of lncRNA FAL1 on HCC cells were investigated by MTT, colony formation, transwell, RT-qPCR, and Western blotting. The miRNA binding sites of lncRNA FAL1 was predicted using RegRNA 2.0 and miR-1236 was validated to target lncRNA FAL1 by luciferase reporter assays and RT-qPCR. Finally, the expression levels of lncRNA FAL1 in serum exosome of HCC patients was also investigated and the role of exosome-mediated lncRNA FAL1 was further investigated by co-culturing with HCC cells.
This study first showed that lncRNA FAL1 was up-regulated in HCC tissues and functioned as an oncogene in HCC. LncRNA FAL1 could accelerate cell proliferation and metastasis as a ceRNA mechanism by competitively binding to miR-1236. Moreover, lncRNA FAL1 was also up-regulated in serum exosome of HCC patients and could transfer lncRNA FAL1 to HCC cells to increase their abilities of cell proliferation and migration.
Taken together, this study indicated that lncRNA FAL1 functions as an oncogenic in HCC and may be a novel diagnostic biomarker or a novel target for the treatment of HCC in future.
Efficient Core Maintenance in Large Dynamic Graphs Rong-Hua Li; Yu, Jeffrey Xu; Rui Mao
IEEE transactions on knowledge and data engineering,
2014-Oct., 2014-10-00, 20141001, Volume:
26, Issue:
10
Journal Article
Peer reviewed
Open access
The k-core decomposition in a graph is a fundamental problem for social network analysis. The problem of k-core decomposition is to calculate the core number for every node in a graph. Previous ...studies mainly focus on k-core decomposition in a static graph. There exists a linear time algorithm for k-core decomposition in a static graph. However, in many real-world applications such as online social networks and the Internet, the graph typically evolves overtime. In such applications, a key issue is to maintain the core numbers of nodes when the graph changes overtime. A simple implementation is to perform the linear time algorithm to recompute the core number for every node after the graph is updated. Such simple implementation is expensive when the graph is very large. In this paper, we propose a new efficient algorithm to maintain the core number for every node in a dynamic graph. Our main result is that only certain nodes need to update their core numbers when the graph is changed by inserting/deleting an edge. We devise an efficient algorithm to identify and recompute the core numbers of such nodes. The complexity of our algorithm is independent of the graph size. In addition, to further accelerate the algorithm, we develop two pruning strategies by exploiting the lower and upper bounds of the core number. Finally, we conduct extensive experiments over both real-world and synthetic datasets, and the results demonstrate the efficiency of the proposed algorithm.
Conventional laser cavities require discontinuity of material property or disorder to localize a light field for feedback. Recently, an emerging class of materials, twisted van der Waals materials, ...have been explored for applications in electronics and photonics. Here we propose and develop magic-angle lasers, where the localization is realized in periodic twisted photonic graphene superlattices. We reveal that the confinement mechanism of magic-angle lasers does not rely on a full bandgap but on the mode coupling between two twisted layers of photonic graphene lattice. Without any fine-tuning in structure parameters, a simple twist can result in nanocavities with strong field confinement and a high quality factor. Furthermore, the emissions of magic-angle lasers allow direct imaging of the wavefunctions of magic-angle states. Our work provides a robust platform to construct high-quality nanocavities for nanolasers, nano light-emitting diodes, nonlinear optics and cavity quantum electrodynamics at the nanoscale.
An efficient strategy for the synthesis of benzofuro2,3-bpyrazines was developed. These tricyclic scaffolds were formed through a multistep cascade sequence, which includes double insertion of ...isonitriles and chemoselective bicyclization. In this reaction, a nanopalladium was used as a recyclable catalyst. Product 3w exhibited excellent anticancer activity toward T-24 (IC50 = 12.5 ± 0.9 μM) and HeLa (IC50 = 14.7 ± 1.6 μM) cells. We also explored the action mechanism of 3w on T-24 cells.
Spin-momentum locking is a direct consequence of bulk topological order and provides a basic concept to control a carrier's spin and charge flow for new exotic phenomena in condensed matter physics. ...However, up to date the research on spin-momentum locking solely focuses on its in-plane transport properties. Here, we report an emerging out-of-plane radiation feature of spin-momentum locking in a non-Hermitian topological photonic system and demonstrate a high performance topological vortex laser based on it. We find that the gain saturation effect lifts the degeneracy of the paired counterpropagating spin-momentum-locked edge modes enabling lasing from a single topological edge mode. The near-field spin and orbital angular momentum of the topological edge mode lasing has a one-to-one far-field radiation correspondence. The methodology of probing the near-field topology feature by far-field lasing emission can be used to study other exotic phenomena. The device can lead to applications in superresolution imaging, optical tweezers, free-space optical sensing, and communication.
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Here, we report the first example of Ni‐catalyzed asymmetric hydrosilylation of 1,1‐disubstituted allenes with high level of regioselectivities and enantioselectivities. The key to achieve this ...stereoselective hydrosilylation reaction was the development of the SPSiOL‐derived bisphosphite ligands (SPSiPO). This protocol features broad substrate scope, excellent functional group, and heterocycle tolerance, thus provides a versatile method for the construction of enantioenriched tertiary allylsilanes in a straightforward and atom‐economic manner. DFT calculations were performed to reveal the reaction mechanism and the origins of the enantioselectivity.
With a newly developed SPSiOL‐base bisphosphite ligand (SPSiPO), Ni‐catalyzed asymmetric hydrosilylation of 1,1‐disubstituted allenes was realized for the first time, delivering the enantioenriched allylsilanes bearing a tertiary carbon stereocenter in high efficiency and 100 % atom‐economy with high chemo‐, regio‐ and enantioselectivities.
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