An Unprecedented CeO2/C Non-Noble Metal Electrocatalyst for Direct Ascorbic Acid Fuel Cells.

Direct ascorbic acid fuel cells (DAAFCs) employ biocompatible ascorbic acid (AA) as fuel, allowing convenient storage, transportation, and fueling as well as avoiding fuel crossover. The AA oxidation reaction (AAOR) largely governs the performance of DAAFCs. However, AAOR electrocatalysts currently have low activity, and state-of-the-art ones are limited to carbon black. Herein, we report the synthesis of an unprecedented AAOR electrocatalyst comprising 3.9 ± 1.1 nm CeO2 nanoparticles evenly distributed on carbon black simply by the wet chemical precipitation of Ce(OH)3 and a subsequent heat treatment. The resultant CeO2/C shows a remarkable AAOR activity with a peak current density of 13.1 mA cm-2, which is 1.7 times of that of carbon black (7.67 mA cm-2). According to X-ray photoelectron spectroscopy (XPS), the surface Ce3+ of CeO2 appears to contribute to the AAOR activity. Furthermore, our density functional theory (DFT) calculation reveals that that the proton of the hydroxyl group of AA can easily migrate to the bridging O sites of CeO2, resulting in a faster AAOR with respect to the pristine carbon, -COOH, and -C=O sites of carbon. After an i-t test, CeO2/C loses 17.8% of its initial current density, which is much superior to that of carbon black. CeO2 can capture the electrons generated by the AAOR to protect the -COOH and -C=O sites from being reduced. Finally, DAAFCs fabricated with CeO2/C exhibit a remarkable power density of 41.3 mW cm-2, which is the highest among proton-exchange-membrane-based DAAFCs in the literature.

Weber Texture Local Descriptor for Identification of Group-Housed Pigs.

The individual identification of group-housed pigs plays an important role in breeding process management and individual behavior analysis. Recently, livestock identification methods based on the side view or face image have strict requirements on the position and posture of livestock, which poses a challenge for the application of the monitoring scene of group-housed pigs. To address the issue above, a Weber texture local descriptor (WTLD) is proposed for the identification of group-housed pigs by extracting the local features of back hair, skin texture, spots, and so on. By calculating the differential excitation and multi-directional information of pixels, the local structure features of the main direction are fused to enhance the description ability of features. The experimental results show that the proposed WTLD achieves higher recognition rates with a lower feature dimension. This method can identify pig individuals with different positions and postures in the pig house. Without limitations on pig movement, this method can facilitate the identification of individual pigs with greater convenience and universality.

miR-194 suppresses epithelial-mesenchymal transition of retinal pigment epithelial cells by directly targeting ZEB1.

BACKGROUND: Epithelial-mesenchymal transition (EMT) of the retinal pigment epithelial (RPE) cells is a critical step in the pathogenesis of proliferative vitreoretinopathy (PVR). Some microRNAs (miRNAs) participate in regulating RPE cell EMT as post-transcriptional regulators. However, the function of miR-194 in RPE cell EMT remains elusive. Here, the role of miR-194 in PVR was investigated. METHODS: Retinal layers were obtained using laser capture microdissection (LCM). Gene expression at the mRNA and protein level in the tissues and cells was examined using quantitative reverse transcription (RT)-polymerase chain reaction and Western blotting, respectively. The related protein expression was observed by immunostaining. The effect of miR-194 on RPE cell EMT was examined by gel contraction, wound healing, and cell migration assays. RNAseq was performed in ARPE-19 with transfection of pSuper-scramble and pSuper-miR-194. The target gene of miR-194 was identified and confirmed via bioinformatics analysis and dual-luciferase reporter assay. ARPE-19 (adult retinal pigment epithelium-19) cells were treated with transforming growth factor (TGF)-ß1 in the same fashion as the in vitro RPE cell EMT model. A PVR rat model was prepared by intravitreous injection of ARPE-19 cells with plasma-rich platelets. RESULTS: miR-194 was preferentially expressed in the RPE cell layer compared with the outer nuclear layer (ONL), inner nuclear layer (INL), and ganglion cell layer in rat retina. RNAseq analysis indicated that miR-194 overexpression was involved in RPE cell processes, including phagocytosis, ECM-receptor interaction, cell adhesion molecules, and focal adhesion. miR-194 overexpression significantly inhibited the TGF-ß1-induced EMT phenotype of RPE cells in vitro. Zinc finger E-box binding homeobox 1 (ZEB1), a key transcription factor in EMT, was confirmed as the direct functional target of miR-194. Knockdown of ZEB1 attenuated TGF-ß1-induced α-smooth muscle actin expression in ARPE-19 cells, and overexpression of miR-194 could significantly reduce the expression of some genes which were up-regulated by ZEB1. Exogenous miR-194 administration in vivo effectively suppressed PVR in the rat model, both functionally and structurally. CONCLUSIONS: Our findings demonstrate for the first time that miR-194 suppresses RPE cell EMT by functionally targeting ZEB1. The clinical application of miR-194 in patients with PVR merits further investigation.