50 research outputs found

    Photobiocidal-triboelectric nanolayer coating of photosensitizer/silica-alumina for reusable and visible-light-driven antibacterial/antiviral air filters

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    Outbreaks of airborne pathogens pose a major threat to public health. Here we present a single-step nanocoating process to endow commercial face mask filters with photobiocidal activity, triboelectric filtration capability, and washability. These functions were successfully achieved with a composite nanolayer of silica-alumina (Si-Al) sol-gel, crystal violet (CV) photosensitizer, and hydrophobic electronegative molecules of 1H, 1H, 2H, 2H-perfluorooctyltriethoxysilane (PFOTES). The transparent Si-Al matrix strongly immobilized the photosensitizer molecules while dispersing them spatially, thus suppressing self-quenching. During nanolayer formation, PFOTES was anisotropically rearranged on the Si-Al matrix, promoting moisture resistance and triboelectric charging of the Si-Al/PFOTES-CV (SAPC)-coated filter. The SAPC nanolayer stabilized the photoexcited state of the photosensitizer and promoted redox reaction. Compared to pure-photosensitizer-coated filters, the SAPC filter showed substantially higher photobiocidal efficiency (∼99.99 % for bacteria and a virus) and photodurability (∼83 % reduction in bactericidal efficiency for the pure-photosensitizer filter but ∼0.34 % for the SAPC filter after 72 h of light irradiation). Moreover, after five washes with detergent, the SAPC filter maintained its photobiocidal and filtration performance, proving its reusability potential. Therefore, this SAPC nanolayer coating provides a practical strategy for manufacturing an antimicrobial and reusable mask filter for use during the ongoing COVID-19 pandemic

    Induction of Neuronal Death by Microglial AGE-Albumin: Implications for Alzheimer’s Disease

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    Advanced glycation end products (AGEs) have long been considered as potent molecules promoting neuronal cell death and contributing to neurodegenerative disorders such as Alzheimer’s disease (AD). In this study, we demonstrate that AGE-albumin, the most abundant AGE product in human AD brains, is synthesized in activated microglial cells and secreted into the extracellular space. The rate of AGE-albumin synthesis in human microglial cells is markedly increased by amyloid-β exposure and oxidative stress. Exogenous AGE-albumin upregulates the receptor protein for AGE (RAGE) and augments calcium influx, leading to apoptosis of human primary neurons. In animal experiments, soluble RAGE (sRAGE), pyridoxamine or ALT-711 prevented Aβ-induced neuronal death in rat brains. Collectively, these results provide evidence for a new mechanism by which microglial cells promote death of neuronal cells through synthesis and secretion of AGE-albumin, thereby likely contributing to neurodegenerative diseases such as AD

    193 nm Ultraviolet Photodissociation of Deprotonated Sialylated Oligosaccharides

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    The fragmentation patterns of deprotonated sialylated oligosaccharides and glycans from fetuin obtained upon collisionally induced dissociation (CID) and 193 nm ultraviolet photodissociation (UVPD) in a linear ion trap are presented. UVPD produced a more extensive series of cross-ring cleavage ions, such as A- and X-type ions, and dual-cleavage internal ions, including A/Y and X/B fragment ions. In addition, UVPD generated unique fragment ions which arise from site-specific cleavage of the triol substituent of the sialic acid residue. In contrast, CID produced more conventional glycosidic cleavages and relatively few A-type ions. UVPD of doubly deprotonated sialylated oligosaccharides produced mostly singly deprotonated fragment ions, whereas the product ions in the CID spectra were overwhelmingly doubly charged ions, an outcome attributed to the more extensive cleavages of sialic acid residues upon UVPD and products from electron photodetachment. The larger array of product ions, including those arising from extensive cross-ring cleavages and dual-cleavage ions, generated by 193 nm UVPD relative to CID gives greater confidence for identification of glycans. Several key site-specific cleavages by UVPD, such as ones involving the sialic acid moieties, provide evidence of glycan composition

    Mass spectrometry-based metabolomics study for delay tomato fruit ripening by sound waves

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    Abstract Tomato (Solanum lycopersicum L.) is one of the most consumed vegetables worldwide. The ripening of tomato is performed for its freshness and represented by color and gene expression. In our previous study, we performed molecular analyses on tomato ripening with and without sound-wave treatment. In the present study, we performed metabolomics analysis of ripening tomatoes with and without sound-wave treatment to expand our knowledge of tomato ripening. To achieve this goal, tomatoes at 7, 10, and 14 d of ripening were selected and analyzed via liquid chromatography–mass spectrometry (LC–MS) and gas chromatography–MS (GC–MS). A total of 33 major metabolites, including 14 LC–MS- and 19 GC–MS-derived metabolites, were assigned based on variable importance projection and p values and subjected to statistical analysis. Apparent morphology and partial least squares–discriminant analysis were consistent with the general ripening process based on color. Moreover, metabolomics analysis showed similar experimental results to those of previous studies. The quantification of metabolites with LC–MS showed decreasing levels of adenosine, tryptophan, and phytosphingosine upon sound-wave treatment. In GC–MS analysis, 4-Aminobutanoic acid and aspartic acid were decreased upon sound-wave treatment. On the other way, the quantity of malic acid, citric acid, and sucrose was increased with the treatment. The findings of this study can assist in the application of sound-wave treatment for delaying ripening in tomatoes and improving their market value

    Characterization of in-situ annealed sub-micron thick Cu(In,Ga)Se-2 thin films

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    Sub-micron thick Cu(In,Ga)Se2 (CIGS) thin films were deposited on Mo-coated soda-lime glass substrates under various conditions by single-stage co-evaporation. Generally, the short circuit current (Jsc) decreased with the decreasing thickness of the absorber layer. However, in this study, Jsc was nearly unchanged with decreasing thickness, while the open circuit voltage (Voc) and fill factor (FF) decreased by 31.9 and 31.1%, respectively. We believe that the remarkable change of Voc and FF can be attributed to the difference in the total amount of injected thermal energy. Using scanning electron microscopy, we confirmed that the surface morphology becomes smooth and the grain size increased after the annealing process. In the X-ray diffraction patterns, the CIGS thin film also showed an improved crystal quality. We observed that the electric properties were improved by the in-situ annealing of CIGS thin films. The reverse saturation current density of the annealed CIGS solar cell was 100 times smaller than that of reference solar cell. Thus, sub-micron CIGS thin films annealed under a constant Se rate showed a 64.7% improvement in efficiency. © 2015 Elsevier B.V.FALS

    Effects of annealing on structural and electrical properties of sub-micron thick CIGS films

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    In this study, we have investigated the electrical and structural properties of sub-micron thick Cu(In,Ga) Se2 (CIGS) films with various in-situ post annealing times. Sub-micron thick CIGS films were deposited on Mo/soda-lime glass (SLG) substrates by single-stage co-evaporation. We decreased the deposition time to 700 s for sub-micron thick CIGS films (≈0.85 μm thickness). After deposition, the CIGS films were annealed under a constant Se rate by a SiC heater for 500-3000 s in a co-evaporator. Increased annealing time led to improved surface morphology and grain size. In the XRD patterns, the CIGS films also showed improved crystal quality for the (112) plane. We suggest that post annealing of sub-micron thick CIGS films at optimized time can be applied for improving device efficiency. The open circuit voltage (Voc) and the fill factor (FF) were increased by 15% and 10%, respectively. The total cell efficiency was increased by more than 35%. © 2013 Elsevier B.V. All rights reserved.
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