9 research outputs found

    Direct, Rapid, Facile Photochemical Method for Preparing Copper Nanoparticles and Copper Patterns

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    We develop a facile method for preparing copper nanoparticles and patterned surfaces with copper stripes by ultraviolet (UV) irradiation of a mixture solution containing a photoinitiator and a copper–amine coordination compound. The copper–amine compound is formed by adding diethanol amine to an ethanol solution of copper chloride. Under UV irradiation, free radicals are generated by photoinitiator decomposition. Meanwhile, the copper–amine coordination compound is rapidly reduced to copper particles because the formation of the copper–amine coordination compound prevents the production of insoluble cuprous chloride. Poly­(vinylpyrrolidone) is used as a capping agent to prevent the aggregation of the as-prepared copper nanoparticles. The capping agent increases the dispersion of copper nanoparticles in the ethanol solution and affects their size and morphology. Increasing the concentration of the copper–amine coordination compound to 0.1 M directly forms a patterned surface with copper stripes on the transparent substrate. This patterned surface is formed through the combination of the heterogeneous nucleation of copper nanoparticles and photolithography. We also investigate the mechanism of photoreduction by UV–vis spectroscopy and gas chromatography–mass spectrometry

    Small-World Brain Network and Dynamic Functional Distribution in Patients with Subcortical Vascular Cognitive Impairment

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    <div><p>To investigate the topological properties of the functional connectivity and their relationships with cognition impairment in subcortical vascular cognitive impairment (SVCI) patients, resting-state fMRI and graph theory approaches were employed in 23 SVCI patients and 20 healthy controls. Functional connectivity between 90 brain regions was estimated using bivariate correlation analysis and thresholded to construct a set of undirected graphs. Moreover, all of them were subjected to a battery of cognitive assessment, and the correlations between graph metrics and cognitive performance were further analyzed. Our results are as follows: functional brain networks of both SVCI patients and controls showed small-world attributes over a range of thresholds(0.15≤sparsity≤0.40). However, global topological organization of the functional brain networks in SVCI was significantly disrupted, as indicated by reduced global and local efficiency, clustering coefficients and increased characteristic path lengths relative to normal subjects. The decreased activity areas in SVCI predominantly targeted in the frontal-temporal lobes, while subcortical regions showed increased topological properties, which are suspected to compensate for the inefficiency of the functional network. We also demonstrated that altered brain network properties in SVCI are closely correlated with general cognitive and praxis dysfunction. The disruption of whole-brain topological organization of the functional connectome provides insight into the functional changes in the human brain in SVCI.</p></div

    Demographic and neuropsychological data.

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    <p>Data are presented as mean ±SD. MMSE = Mini-Mental State Examination. CAMCOG-C = Cambridge cognitive examination-Chinese version;ADL = Activities of Daily Living Scale; GDS = Global deterioration scale; MoCA = Montreal Cognitive Assessment, CDR = Clinical Dementia Rating; AVLT = Auditory-Verbal Learning Test;WMH = white matter hyperintensities</p><p><sup>a</sup> two-tail Pearson chi-square test</p><p><sup>b</sup> were obtained using a two-sample two-tail t-test.</p><p>Demographic and neuropsychological data.</p

    Significant differences in all metrics between SVIC patients and controls in the range of 0.05 ≤ S<sub>thr</sub> ≤ 0.40.

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    <p>t, statistical value showing nodal topological properties difference (P < 0.05,FDR corrected) between two groups (positive t-value means increased topological properties in the SVCI group); DCG: median cingulate and paracingulate gyri; R, right; L, left.</p><p>Significant differences in all metrics between SVIC patients and controls in the range of 0.05 ≤ S<sub>thr</sub> ≤ 0.40.</p

    Distribution of brain regions in which small-world properties decreased(blue) or increased(red) significantly in SVCI patients compared to the healthy controls over a wide range of correlation thresholds (0.05

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    <p>(A) global efficiency; (B) clustering coefficient; (C) characteristic path length; (D) local efficiency; DCG = median cingulate and paracingulate gyri; MTG = middle temporal gyrus; PUT = putamen; PAL = pallidum; TPOsup = temporalpole: superior temporal gyrus; STG = superior temporal gyrus; SMA = supplementary motor area; PCUN = Precuneus; PoCG = postcentral gyrus; OLF = Olfactory cortex; PCL = paracentral lobule; IOG = Inferior occipital gyrus</p

    Flower-like Surface of Three-Metal-Component Layered Double Hydroxide Composites for Improved Antibacterial Activity of Lysozyme

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    Microbes play an important function in our lives, while some pathogenic bacteria are responsible for many infectious diseases, food safety, and ecological pollution. Layered double hydroxide (LDH) is a kind of natural two-dimensional material and has been applied in many fields. Lysozyme is a green natural antibacterial agent, while the antimicrobial activity of lysozyme is not as good as antibiotics. We use a different ratio of cations to tune the morphology of LDH covered with lysozyme to enhance the antibacterial ability of lysozyme. We synthesize MgAl-LDH, ZnAl-LDH, and ZnMgAl-LDH covered with lysozyme, characterize the structure and morphology, test the antibacterial in culture media, and evaluate the biotoxicity in vitro and in vivo. The flower-like structure of ZnMgAl-LDH has a rough surface, covered with lysozyme with a perfect ring, and presents good antibaterial properties and promotes wound healing of mice. The bloom flower structure of ZnMgAl-LDH can enhance the loading rate of lysozyme; meanwhile, the rougher surface can adhere more bacteria, so lyso@ZnMgAl-LDH presents better antibacterial activity than the binary LDHs

    Facile Method for the Fabrication of Robust Polyelectrolyte Multilayers by Post-Photo-Cross-Linking of Azido Groups

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    In this letter, we have developed a facile method to enhance the stability of polyelectrolyte multilayers. We fabricate conventional polyelectrolyte multilayers of PAH/PAA through electrostatic layer-by-layer (LbL) assembly and then postinfiltrate photosensitive cross-linking agent 4,4′-diazostilbene-2,2′-disulfonic acid disodium salt into the LbL films. After cross-linking by UV irradiation, the stability of the photo-cross-linked multilayer is highly improved as evidenced by the lack of dissolution under ultrasonication in saturated SDS aqueous solutions for 10 min. Moreover, by taking advantage of the different stability of the LbL film before and after UV irradiation, a patterned surface can be achieved
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