2,255 research outputs found

    Quantitative assessment of image motion blur in diffraction images of moving biological cells

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    Motion blur (MB) presents a significant challenge for obtaining high-contrast image data from biological cells with a polarization diffraction imaging flow cytometry (p-DIFC) method. A new p-DIFC experimental system has been developed to evaluate the MB and its effect on image analysis using a time-delay-integration (TDI) CCD camera. Diffraction images of MCF-7 and K562 cells have been acquired with different speed-mismatch ratios and compared to characterize MB quantitatively. Frequency analysis of the diffraction images shows that the degree of MB can be quantified by bandwidth variations of the diffraction images along the motion direction. The analytical results were confirmed by the p-DIFC image data acquired at different speed-mismatch ratios and used to validate a method of numerical simulation of MB on blur-free diffraction images, which provides a useful tool to examine the blurring effect on diffraction images acquired from the same cell. These results provide insights on the dependence of diffraction image on MB and allow significant improvement on rapid biological cell assay with the p-DIFC method

    Refractive index in holographic superconductors

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    With the probe limit, we investigate the behavior of the electric permittivity and effective magnetic permeability and related optical properties in the s-wave holographic superconductors. In particular, our result shows that unlike the strong coupled systems which admit a gravity dual of charged black holes in the bulk, the electric permittivity and effective magnetic permeability are unable to conspire to bring about the negative Depine-Lakhtakia index at low frequencies, which implies that the negative phase velocity does not appear in the holographic superconductors under such a situation.Comment: JHEP style, 1+15 pages, 11 figures, version to appear in JHE

    Preparation of Microporous Carbon from Sargassum horneri by Hydrothermal Carbonization and KOH Activation for CO2 Capture

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    High-performance microporous activated carbon (AHC) for CO2 capture was prepared from an emerging marine pollutant, Sargassum horneri, via hydrothermal carbonization (HTC) and KOH activation. The as-synthesized carbon material was characterized by N2 sorption-desorption measurement, TGA, SEM, XRD, FTIR, and elemental analysis. Impressively, the activated carbon exhibited high specific surface area (1221 m2/g), narrow distributed micropores (∼0.50 nm), and a relatively high nitrogen content (3.56 wt.%), which endowed this carbon material high CO2 uptake of 101.7 mg/g at 30°C and 1 bar. Moreover, the carbon material showed highly stable CO2 adsorption capacity and easy regeneration over four adsorption-desorption cycles. Two kinetic models were employed in this work and found that the pseudo-first-order kinetic model (R2 = 0.99) provided the best description. In addition, the high CO2 uptake is mainly attributed to the presence of abundant narrow microporous. The macroporous structure of hydrochar (HC) played an important role in the production of microporous carbon with high adsorption properties. This work provides an efficient strategy for preparing microporous activated carbon from Sargassum horneri, and AHC is a promising candidate acting as an efficient CO2 adsorbent for further industrial application

    Non-Equilibrium Field Dynamics of an Honest Holographic Superconductor

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    Most holographic models of superconducting systems neglect the effects of dynamical boundary gauge fields during the process of spontaneous symmetry-breaking. Usually a global symmetry gets broken. This yields a superfluid, which then is gauged "weakly" afterwards. In this work we build (and probe the dynamics of) a holographic model in which a local boundary symmetry is spontaneously broken instead. We compute two-point functions of dynamical non-Abelian gauge fields in the normal and in the broken phase, and find non-trivial gapless modes. Our AdS3 gravity dual realizes a p-wave superconductor in (1+1) dimensions. The ground state of this model also breaks (1+1)-dimensional parity spontaneously, while the Hamiltonian is parity-invariant. We discuss possible implications of our results for a wider class of holographic liquids.Comment: 32 pages, 12 figures; v3: string theory derivation of setup added (section 3.1), improved presentation, version accepted by JHEP; v2: paragraph added to discussion, figure added, references added, typos correcte

    A new assessment model for tumor heterogeneity analysis with [18]F-FDG PET images

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    It has been shown that the intratumor heterogeneity can be characterized with quantitative analysis of the [18]F-FDG PET image data. The existing models employ multiple parameters for feature extraction which makes it difficult to implement in clinical settings for the quantitative characterization. This article reports an easy-to-use and differential SUV based model for quantitative assessment of the intratumor heterogeneity from 3D [18]F-FDG PET image data. An H index is defined to assess tumor heterogeneity by summing voxel-wise distribution of differential SUV from the [18]F-FDG PET image data. The summation is weighted by the distance of SUV difference among neighboring voxels from the center of the tumor and can thus yield increased values for tumors with peripheral sub-regions of high SUV that often serves as an indicator of augmented malignancy. Furthermore, the sign of H index is used to differentiate the rate of change for volume averaged SUV from its center to periphery. The new model with the H index has been compared with a widely-used model of gray level co-occurrence matrix (GLCM) for image texture characterization with phantoms of different configurations and the [18]F-FDG PET image data of 6 lung cancer patients to evaluate its effectiveness and feasibility for clinical uses. The comparison of the H index and GLCM parameters with the phantoms demonstrate that the H index can characterize the SUV heterogeneity in all of 6 2D phantoms while only 1 GLCM parameter can do for 1 and fail to differentiate for other 2D phantoms. For the 8 3D phantoms, the H index can clearly differentiate all of them while the 4 GLCM parameters provide complicated patterns in the characterization. Feasibility study with the PET image data from 6 lung cancer patients show that the H index provides an effective single-parameter metric to characterize tumor heterogeneity in terms of the local SUV variation, and it has higher correlation with tumor volume change after radiotherapy (R2 = 0.83) than the 4 GLCM parameters (R2 = 0.63, 0.73, 0.59 and 0.75 for Energy, Contrast, Local Homogeneity and Entropy respectively). The new model of the H index has the capacity to characterize the intratumor heterogeneity feature from 3D [18]F-FDG PET image data. As a single parameter with an intuitive definition, the H index offers potential for clinical applications

    The study on the structure of exotic states χc1(3872)\chi_{c 1}(3872) via beauty-hadron decays in pppp collisions at s=8TeV\sqrt{s}=8\,\mathrm{TeV}

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    A dynamically constrained phase-space coalescence (DCPC) model was introduced to study the exotic state χc1(3872)\chi_{c 1}(3872) yield for three possible structures: tetraquark state, nuclear-like state, and molecular state respectively, where the hadronic final states generated by the parton and hadron cascade model (PACIAE). The χc1(3872)\chi_{c 1}(3872)/ψ(2S)\psi (2S) cross-section ratio from beauty-hadron decays (non-prompt) based on the χc1(3872)\chi_{c 1}(3872) or ψ(2S)J/ψπ+π\psi (2S)\to J/\psi{\pi^+}{\pi^-} bound state in the decay chains as a function of charged-particle multiplicity and transverse momentum in pppp collisions at s=8TeV\sqrt{s}=8\,\mathrm{TeV} are calculated. A tetraquark state scenario from PACIAE+DCPC model shows better agreement with the LHCb and ATLAS measurements for the non-prompt χc1(3872)\chi_{c 1}(3872)/ψ(2S)\psi(2S) cross-section ratio distributions, indicating that the χc1(3872)\chi_{c 1}(3872) is more likely to be a compact tetraquark state

    (E)-N′-(5-Chloro-2-hydroxy­benzyl­idene)-3,5-dihydroxy­benzohydrazide mono­hydrate

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    In the title compound, C14H11ClN2O4·H2O, the dihedral angle between the two benzene rings is 8.5 (2)° and an intra­molecular O—H⋯N hydrogen bond is observed in the Schiff base mol­ecule. In the crystal structure, the water mol­ecule accepts an N—H⋯O hydrogen bond and makes O—H⋯O hydrogen bonds to two further Schiff base mol­ecules. Further inter­molecular O—H⋯O hydrogen bonds lead to the formation of layers parallel to the bc plane
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