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The protective effects of pigment epithelium-derived factor (PEDF) against X-ray-induced retinopathy were investigated in vitro and in vivo. The function of PEDF was suppressed using PEDF receptor inhibitors and transfection of siRNA in human retinal pigment epithelium cell line ARPE-19. The decreased expression of PEDF was measured using quantitative fluorescent reverse transcription PCR and ELISA. Cell viability after X-ray exposure was monitored using the CCK-8 method. Both left and right irradiation fields were set up to deliver X-rays to the eyes of mice using a small animal radiotherapy simulation machine. Each field was irradiated with 10 Gy. The total dose was 20 Gy. The saline containing 2 nmol/L PEDF-34, a 34-amino acid fragment at positions 44~77 of the PEDF, was prepared. After irradiation, the mice were treated with eye drops every day for 4 weeks. After 8 weeks, the eyeballs were harvested for HE and TUNEL staining and checked for retinopathy and apoptosis. The results showed that pretreatment via PEDF receptor inhibitors and the reduction of PEDF expression aggravated X-ray-induced cell damage in ARPE-19 cells, while PEDF-34 exerted protective effects against X-ray-induced cell damage. Eight weeks after irradiation with a dose of 20 Gy, the experimental mice demonstrated aberrant morphology in the retinal pigment epithelial cell layer and apoptotic cells in the outer nuclear layer. The PEDF-34-treated group maintained a structurally normal retina and had no apoptotic cells. The current study indicates that PEDF has a protective effect against radiation-induced retinopathy, and the PEDF-34-containing eye drops could alleviate the injury. Our findings may provide an experimental basis for a new treatment approach for radiation retinopathy.

Accelerating sulfur conversion catalysis to alleviate the shuttle effect has become a novel paradigm for effective Li−S batteries. Although nitrogen‐coordinated metal single‐atom (M−N4) catalysts have been investigated, further optimizing its utilization rate and catalytic activities is urgently needed for practical applications. Inspired by the natural alveoli tissue with interconnected structure and well‐distributed enzyme catalytic sites on the wall for the simultaneously fast diffusion and in situ catalytic conversion of substrates, here, we proposed the controllable synthesis of bioinspired carbon cathode with interconnected porous structure and asymmetric coordinated V−S1N3 sites for efficient and stable Li−S batteries. The enzyme‐mimetic V−S1N3 shows asymmetric electronic distribution and high tunability, therefore enhancing in situ polysulfide conversion activities. Experimental and theoretical results reveal that the high charge asymmetry degree and large atom radius of S in V−S1N3 result in sloping adsorption for polysulfide, thereby exhibiting low thermodynamic energy barriers and long‐range stability (0.076 % decay over 600 cycles). [ABSTRACT FROM AUTHOR]

This study examines the climatic characteristics of 202 Jianghuai cyclones and their linkage with precipitation during the Meiyu period from 1961 to 2020. The results show that cyclones mainly originate from the eastern and western Hubei Province. Additionally, we explore the statistical characteristics of intensity, radius and their positive correlation. In studying the decadal variation of cyclones, we find a similar evolution between the cyclones and Meiyu precipitation. Therefore, we further investigate the correlation between the Jianghuai cyclones and the precipitation during the Meiyu period. There is a positive correlation coefficient of 0.77 between them. Notably, the percentage of precipitation affected by cyclone activities can reach up to 47 %. The anomalous increase in precipitation caused by cyclones north of 27° N can reach a maximum of 7 mm d -1. When a cyclone exists, a significant negative geopotential height anomaly at the 500 hPa level over Mongolia can be traced back to day -4. The abnormally enhanced WPSH (western Pacific subtropical high), southwesterly low-level jet and negative geopotential height are the dominant factors causing abnormal precipitation during Jianghuai cyclones. Before and after the cyclone develops, water vapor flux and divergence from low latitudes increase abnormally, providing sufficient water vapor conditions for the generation of cyclone precipitation. [ABSTRACT FROM AUTHOR]