9,545 research outputs found

    High sensitivity cymbal-based accelerometer

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    Author name used in this publication: Cheng-Liang SunAuthor name used in this publication: K. H. LamAuthor name used in this publication: S. H. ChoyAuthor name used in this publication: H. L. W. ChanAuthor name used in this publication: X.-Z. ZhaoAuthor name used in this publication: C. L. Choy2005-2006 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

    Operation-State Monitoring and Energization-Status Identification for Underground Power Cables by Magnetic Field Sensing

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    The effect of an NgR1 antagonist on the neuroprotection of cortical axons after cortical infarction in rats

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    Topological modes bound to dislocations in mechanical metamaterials

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    Mechanical metamaterials are artificial structures with unusual properties, such as negative Poisson ratio, bistability or tunable vibrational properties, that originate in the geometry of their unit cell. At the heart of such unusual behaviour is often a soft mode: a motion that does not significantly stretch or compress the links between constituent elements. When activated by motors or external fields, soft modes become the building blocks of robots and smart materials. Here, we demonstrate the existence of topological soft modes that can be positioned at desired locations in a metamaterial while being robust against a wide range of structural deformations or changes in material parameters. These protected modes, localized at dislocations, are the mechanical analogue of topological states bound to defects in electronic systems. We create physical realizations of the topological modes in prototypes of kagome lattices built out of rigid triangular plates. We show mathematically that they originate from the interplay between two Berry phases: the Burgers vector of the dislocation and the topological polarization of the lattice. Our work paves the way towards engineering topologically protected nano-mechanical structures for molecular robotics or information storage and read-out.Comment: 13 pages, 6 figures; changes to text and figures and added analysis on mode localization; see http://www.lorentz.leidenuniv.nl/~paulose/dislocation-modes/ for accompanying video

    Anti-Tumor Effect of Cactus Polysaccharides on Lung Squamous Carcinoma Cells (SK-MES-1)

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    Background: Cactus polysaccharides are the active components of Opuntia dillenii which have been used extensively in folk medicine. In thisstudy, we investigate the anti-tumor effect of cactus polysaccharides on lung squamous carcinoma cells SK-MES-1.Materials and Methods: The inhibitory effect of Cactus polysaccharides on lung squamous carcinoma cells were detected by MTT assay. Cellcycle was determined by flow cytometry and cell apoptosis was determined by AnnexinV assay. Western-blotting was applied to detect P53 andPTEN protein expression in the cells treated with cactus polysaccharides.Results: Results showed that different concentrations of wild cactus polysaccharides prevent SK-MES-1 cells growth and induces S phase arrest.The data also revealed that cactus polysaccharides cause apoptosis in SK-MES-1 cells determined by Annexin-V assay. Furthermore, cactuspolysaccharides induced growth arrest and apoptosis may be due to the increase of P53 and phosphatase and tension homolog deleted onchromosome ten (PTEN) protein.Conclusion: Cactus polysaccharides have anti-tumor activity on lung squamous carcinoma cells.Key words: Cactus polysaccharides, Lung squamous carcinoma, Anti-tumor effect, P53, PTEN Abbreviations: PTEN :phosphatase and tension homolog deleted on chromosome ten; NSCLC: Non-small-cell lung cancer; FBS :Phosphate buffered saline; MTT:3-(4, 5-Dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide; PBS: Phosphate buffered saline; DMSO:Dimethyl sulfoxide; PI: Propidium iodide

    Cardiac parameters analysis for zebrafish heart regeneration based on highfrequency ultrasound imaging

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    Author name used in this manuscript: K. Kirk ShungRefereed conference paper2010-2011 > Academic research: refereed > Refereed conference paperAccepted ManuscriptPublishe

    Hybrid polypyrrole and polydopamine nanosheets for precise Raman/photoacoustic imaging and photothermal therapy

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    The development of near-infrared light (NIR)-responsive conductive polymers provides a useful theranostic platform for malignant tumours by maximizing spatial resolution with deep tissue penetration for diagnosis and photothermal therapy. Herein, we demonstrated the self-assembly of ultrathin two-dimensional (2D) polypyrrole nanosheets utilizing dopamine as a capping agent and a monolayer of octadecylamine as a template. The 2D polypyrrole-polydopamine nanostructure (DPPy) had tunable size distribution which showed strong absorption in the first and second near-infrared windows, enabling photoacoustic imaging and photothermal therapy. The hybrid double-layer was demonstrated to increase Raman intensity for 3D Raman imaging (up to two orders of magnitude enhancement and spatial resolution up to 1 μm). The acidic environment drove reversible doping of polypyrrole, which could be detected by Raman spectroscopy. The combined properties of the nanosheets could substantially enhance performance in dual-mode Raman and photoacoustic guided photothermal therapy, as shown by the 69% light to heat conversion efficiency and higher cytotoxicity against cancer spheroids. These pH-responsive features highlight the potential of 2D conductive polymers for applications in accurate, highly efficient theranostics
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