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Cigarette smoke exposure leads to chronic obstructive pulmonary disease (COPD). We investigated the role and underlying mechanisms of methyltransferase-like 3 (METTL3) and autophagy-related protein 5 (ATG5) in the progression of COPD. In a COPD mouse model exposed to cigarette smoke, lung tissues showed increased levels of METTL3, p-p65/ p65, autophagy markers (LC3 and ATG5), inflammatory factors (interleukin-6, IL-8, and TNF-α), and airway remodeling markers (N-cadherin, α-SMA, and Tn-C), while p62 and E-cadherin levels were decreased. Expression of METTL3 and ATG5 was positively correlated. These findings are consistent with observations in RAW264.7 mouse mononuclear macrophages exposed to cigarette smoke extract (CSE). CSE inhibited cell viability while promoting autophagy. METTL3 knockdown counteracted CSE effects, and ATG5 overexpression reversed METTL3 knockdown outcomes. Methylated RNA immunoprecipitation-qPCR showed that METTL3 knockdown reduced m6A, and the actinomycin D assay suggested that METTL3 knockdown reduced ATG5 mRNA levels and lowered ATG5 mRNA stability. METTL3-knockdown RAW264.7 reduced the inflammation and airway remodeling markers in the co-cultured mouse bronchial epithelial cells. In conclusion, inhibition of the METTL3-ATG5 axis-mediated macrophage detrimental autophagy in COPD could alleviate bronchial epithelial cell inflammation and reduce airway remodeling.

In order to simultaneously determine the values of total solar irradiance (TSI) and the Earth's radiation at the top of the atmosphere (TOA) on board the Fengyun-3F satellite, a spaceborne relative radiometer (SRR) was developed. It adopts a dual-channel structure, including a solar radiometer channel (SR) with an unobstructed field of view (FOV) of 1.5° and an Earth radiometer channel (ER) with a wide field of view (WFOV) of 95.3° and a diameter of about 1900 km on the ground. Before the launch, both the SR and ER were calibrated. The SR, installed on the inner frame of the solar tracker of the SIM-II (solar irradiance monitor-II), is used to observe rapid changes in solar radiance with the SIAR (solar irradiance absolute radiometer), an electrical-substitution radiometer, on orbit. The ER is mounted on the U-shaped frame of the solar tracker, directly pointing in the nadir direction. Additionally, a dark space observation mode is used to determine the on-orbit background noise and lunar observation mode for on-orbit calibration. In this article, the instrument design and working principle of the SRR is first introduced, and an analysis of the measurement model of the ER, the WFOV channel of the SRR, is focused on. Finally, ground test results of the SRR are introduced. [ABSTRACT FROM AUTHOR]

Because of the essential difference between micro-toughness and macro-toughness, the indiscriminate application of deep notch tests may result in serious errors of micro-toughness associated with shallow cracks or flaws in ceramics. Here, the micro-toughness values of ZrB2, ZrB2-SiC and ZrB2-SiC-Grapite ceramics were successfully measured through ultra-shallow sharp V-notches (depth less than 40 μm, the ratio of notch depth to sample height less than 0.01) produced by nanosecond laser on the surface of bending bars for the first time. Results indicated that the micro-toughness values obtained from these three typical ceramics were significantly lower than the macro-toughness values measured from deep notches. Furthermore, conflicts may arise when comparing the micro- with macro-toughness between different materials, such as the macro-toughness of ZrB2-SiC-G was larger than that of ZrB2-SiC, while a contrary result was obtained for micro-toughness. Compared with the indentation method, improved accuracy of micro-toughness measurement could be obtained by this method. [ABSTRACT FROM AUTHOR]