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Two-dimensional spectral images are generally distorted. Spectrum extraction operation is affected by such distortion, which reduces the quality of one-dimensional spectral data. Aiming at above problem, an effective correction method for the distorted two-dimensional spectral images based on neural network is proposed. Firstly, by extracting the center line of each fiber from the flat-field spectrum and fitting the equal-wavelength line at each specific wavelength from the calibration lamp spectrum, data that represent distortion characteristics from two-dimensional spectral images can be obtained. The training samples are thus constructed according to these two sets of feature lines. Secondly, a neural network model is then designed and trained to fit the relation between the pixel coordinates of the image before and after correction. Therefore, all pixel coordinate values of the corrected image can be calculated by the model. Finally, the flux values of the corrected image are filled one-to-one in accord with the flux value of the original distorted image. The correction experiments are carried out with the flat-field spectrum, calibration lamp spectrum, and object spectrum respectively. The spectral extraction results of the object spectrum before and after correction are compared. Experimental results prove that the method can correct the distorted two-dimensional spectral image effectively and improve quality of one-dimensional spectral data to an extent.

Novel cooperative ZnS–CdSe@Co/N–C core/shell composites were successfully prepared by the chelation of CoCl2 on the surface of ZnS–CdSe nanoparticles and further modification by N-doped carbon spheres. These composites possessed a heterojunction and cocatalyst properties and can reduce the energy band, promote the activity and selectivity, and enhance the catalyst service life. Therefore these composites may offer a new strategy to regulate the optical absorption and photocatalytic properties of semiconductor materials. [ABSTRACT FROM AUTHOR]

A luminescence sensor based on an europium(III)-based lanthanide–organic framework, [Eu(BCB)(DMF)]·(DMF)1.5(H2O)2 (1), was synthesized via a solvothermal method using 4,4′,4′′-benzenetricarbonyltribenzoic acid (H3BCB) as a bridging ligand. Single-crystal X-ray diffraction indicates that Eu centers are eight-coordinated with a trigonal dodecahedron and a square antiprismatic configuration, and adjacent Eu atoms are bridged by BCB organic linkers to form a 3D rod-packing structure. Photoluminescence studies show that compound 1 emits bright red luminescence and behaves as a multi-responsive luminescent sensor toward 4-nitrophenol (4-NP) and I− and Fe3+ ions in water with high sensitivity, selectivity and low detection limits. Furthermore, the possible luminescence sensing mechanisms were also investigated by PXRD analysis, UV-vis spectroscopy and X-ray photoelectron spectroscopy (XPS). The recognition mechanism for 4-NP and I− ions can be attributed to the competition absorption and that for Fe3+ ions is considered to be a multi-quenching mechanism dominated by competition absorption. This study demonstrates that the lanthanide-based MOF might be a promising candidate for the detection of 4-NP and I− and Fe3+ ions in aqueous medium. [ABSTRACT FROM AUTHOR]

The multi-modal imaging contrast agent has been attracted an increased interest to the tumor detecting and diagnosis in these recent years since the multi-modal imaging technology combines the advantages of several medical imaging modalities. A water-soluble fullerenol probe containing glypican-3 monoclonal antibody (GPC3-mAb) group mAb-GPC3-C60(OH)10-(TMIO)3-(NI)3 was synthesized by the incorporation of 5-formyl-1,1,3,3-tetramethylisoindolin-2-yloxyl (FTMIO), naphthalimide (NI) and GPC3-mAb as a tumor-targeting group into fullerenol C60(OH)11. This nanomaterial was further characterized by FTIR, UV, MS, fluorescence, etc., and then its properties including electron paramagnetic resonance (EPR), particle size, electrophoresis, electrochemical assay, cell cytotoxicity, cell uptake and fluorescent imaging of HeLa tumor cells in vitro were also evaluated. Experiment results indicated that mAb-GPC3-C60(OH)10-(TMIO)3-(NI)3 had similar fluorescent properties as NI and similar electrochemical and redox properties as 5-carboxy-1,1,3,3-tetramethylisoindolin-2-yloxyl (CTMIO). Moreover, mAb-GPC3-C60(OH)10-(TMIO)3-(NI)3 possessed low cell cytotoxicity, good fluorescence and good tumor-targeting property. Meanwhile, mAb-GPC3-C60(OH)10-(TMIO)3-(NI)3 can be taken up highly by HeLa tumor cells, achieve good green fluorescent imaging in tumor cells and highly enhance the contrast of fluorescent images. Therefore, mAb-GPC3-C60(OH)10-(TMIO)3-(NI)3 can disperse homogeneously in aqueous solution and be used as a potential tumor-targeting dual-modal contrast agent for EPR imaging/fluorescence imaging (EPRI/FI). [ABSTRACT FROM AUTHOR]