Search

Infection by bacteria leads to tissue damage and inflammation, which need to be tightly controlled by host mechanisms to avoid deleterious consequences. It is previously reported that TMEM16F, a calcium‐activated lipid scramblase expressed in various immune cell types including T cells and neutrophils, is critical for the control of infection by bacterium Listeria monocytogenes (Lm) in vivo. This function correlated with the capacity of TMEM16F to repair the plasma membrane (PM) damage induced in T cells in vitro, by the Lm toxin listeriolysin O (LLO). However, whether the protective effect of TMEM16F on Lm infection in vivo is mediated by an impact in T cells, or in other cell types, is not determined. Herein, the immune cell types and mechanisms implicated in the protective effect of TMEM16F against Lm in vivo are elucidated. Cellular protective effects of TMEM16F correlated with its capacity of lipid scrambling and augment PM fluidity. Using cell type‐specific TMEM16F‐deficient mice, the indication is obtained that TMEM16F expressed in liver Kupffer cells (KCs), but not in T cells or B cells, is key for protection against Listeria in vivo. In the absence of TMEM16F, Listeria induced PM rupture and fragmentation of KCs in vivo. KC death associated with greater liver damage, inflammatory changes, and dysregulated liver metabolism. Overall, the results uncovered that TMEM16F expressed in Kupffer cells is crucial to protect the host against Listeria infection. This influence is associated with the capacity of Kupffer cell‐expressed TMEM16F to prevent excessive inflammation and abnormal liver metabolism. [ABSTRACT FROM AUTHOR]

To prepare a high quality Fe-based ceramic composite coating, 17-4ph+30% WC alloy powder was clad onto a 17-4ph stainless steel substrate by high speed laser cladding (HSLC) and a metal matrix composite (MMC) clad without cracks and pores was achieved. The WC particle distribution, microstructure formation and evolution mechanism of the MMC laser clad were studied in detail. The results show that the phase composition of the MMC laser clad mainly includes γ-Fe, W2C, WC, Ni3Fe, Cr23C6, etc. The WC particles in the MMC laser clad show a good metallurgical bonding with the 17-4ph substrate, the dilution rate of the clad is low and the higher heat input causes more WC particles to melt and decompose, generating more hard strengthening phases. The grain refinement strengthening, solid solution strengthening and second phase strengthening are more prominent, which provides a scientific basis for optimizing the preparation of high quality Fe-based ceramic composite coatings. [ABSTRACT FROM AUTHOR]

In this paper, a surface with fractal characteristics on the basis of a continuous function has been constructed. We conducted a study on the Box dimension and the Hausdorff dimension of this surface, building upon this foundation. We found that there exists a certain relationship between the dimensionality of the surface with fractal characteristics, which is obtained from the rotation of a fractal curve. [ABSTRACT FROM AUTHOR]

The coal mine roller is a key component in the mine belt conveyor system. The work described herein involved a Fe-based clad prepared on a 42CrMo steel roller substrate by laser cladding in order to improve the service life and performance of the coal mine roller. The chemical composition, microstructure, properties, microhardness, wear resistance and salt spray corrosion performance of the laser clad layer and substrate under the optimum process parameters were systematically studied. The results showed that laser scanning speed and laser power mainly affect the width, height and depth of the clad. The process parameters were optimized by a series of orthogonal experiments. The optimal process parameters were a laser power of 1700 W, scanning speed of 6 mm/s and powder feed rate of 15 g/min. The laser clad mainly composed γ-Fe and the compounds of Fe and Cr, such as CrFe4and CrFe19. Along the depth direction of laser clad the microstructure gradually changed from planar crystal and bits of dendrite crystal to equiaxed crystal. The grains at the top of the direction of the laser cladding layer were further refined. The hardness of the laser clad was increased by about 2.2 times that of the substrate. The friction and the loss of weight from wear test and salt spray corrosion of the laser clad show that the weight gain is much smaller than that of the substrate. The experimental results show that the wear resistance and corrosion resistance are improved significantly. [ABSTRACT FROM AUTHOR]

This study used a potted experiment to apply biochar to black soil (BCS) and saline-alkali soil (BSAS) in Northeast China, with a dosage of 0 and 300 g biochar/pot applied, respectively. The original black soil (CS) and saline-alkali soil (SAS) were used as controls to investigate the effects of different particle sizes of soil aggregates on the activity of enzymes related to carbon, nitrogen, and phosphorus cycle. Compared with CS and SAS, the soil organic matter (SOM) values for biochar added into the black soil (BCS) and saline-alkali soil (BSAS) treatments were increased significantly by 41.86 % and 31.98 %. Compared with CS, BCS significantly increased the polyphenol oxidase and ß-1,4-glucosidase activity. Polyphenol oxidation activity, endo-1,4-ß-D-glucanohydrolase activity, ß-1,4-glucosidase activity and xylanase activity are more active in particles with a diameter of >2 mm. The alkaline phase activity and Coenzyme activity with BCS treatment was highest in soil aggregates with sizes of 1~2 mm and >5 mm, respectively. Mantel test analysis shows a highly significant effects between SOM and total nitrogen content (TN) with soil nitrogen, phosphorus, and potassium cycling. Therefore, from the perspective of soil enzyme activities, application of biochar is more effective in promoting soil bio-fertility in northeastern soil of China. Biochar to the soil is more likely to promote the improvement of soil biological fertility. [ABSTRACT FROM AUTHOR]

PIEZO1 is a mechanosensitive channel that converts applied force into electrical signals. Partial molecular structures show that PIEZO1 is a bowl-shaped trimer with extended arms. Here we use cryo-electron microscopy to show that PIEZO1 adopts different degrees of curvature in lipid vesicles of different sizes. We also use high-speed atomic force microscopy to analyse the deformability of PIEZO1 under force in membranes on a mica surface, and show that PIEZO1 can be flattened reversibly into the membrane plane. By approximating the absolute force applied, we estimate a range of values for the mechanical spring constant of PIEZO1. Both methods of microscopy demonstrate that PIEZO1 can deform its shape towards a planar structure. This deformation could explain how lateral membrane tension can be converted into a conformation-dependent change in free energy to gate the PIEZO1 channel in response to mechanical perturbations. Cryo-electron microscopy and high-speed atomic force microscopy reveal that PIEZO1 can reversibly deform its shape towards a planar structure, which may explain how the PIEZO1 channel is gated in response to mechanical stimulation., Author(s): Yi-Chih Lin [sup.1] [sup.2] , Yusong R. Guo [sup.3] , Atsushi Miyagi [sup.1] [sup.2] , Jesper Levring [sup.3] , Roderick MacKinnon [sup.3] , Simon Scheuring [sup.1] [sup.2] Author Affiliations: [...]

The hydraulic column is the key component of the hydraulic support in the mining environment. To improve a hydraulic column's reliability and service life, the Fe-based laser clad layer was prepared on 27SiMn steel substrate using a high power diode laser (HPDL). The results show that the best process parameters are the laser power of 3000 W, the scanning speed of 5 mm/s, the feeding fraction of 16 g/min and the lapping rate of 50%. The macroscopic morphology of the laser clad layer has no cracks, pits and other defects. The laser clad layer has a fine and uniform microstructure and can form a metallurgical bonding with the 27SiMn steel substrate. Elements distribution is uniform and it appears fluctuation around the melting line. The cladding hardness is 1.3 times higher than the substrate and the wear resistance is 7.7 times higher than the substrate. The self-corrosion potential of the laser clad layer is significantly shifted positively and has a significant passivation region. After 96 hours of salt pray corrosion test, the surface of the laser clad layer is still smooth. The laser clad layer has better corrosion resistance and performance than the substrate, which can meet the requirements of hydraulic support in the mining environment. [ABSTRACT FROM AUTHOR]