Inversion of soil salinity in China's Yellow River Delta using unmanned aerial vehicle multispectral technique.

The rapid and accurate acquisition of soil property information, especially the soil salinity (SS), is required for saline soil management in the Yellow River Delta (YRD). In this study, Lijin County and Kenli District were selected as study area. Unmanned aerial vehicle (UAV) multispectral data and soil sample data were acquired from March 25 to 28, 2019. Pearson correlation and gray correlation analyses were first used to screen sensitive spectral bands/indices, which were used for model parameters construction. Three machine learning and one statistical analysis methods were used to construct the SS inversion models. The results found that the gray correlation coefficient value were greater than the Pearson coefficient value for all bands and indices. Based on the gray correlation coefficient, nine sensitive bands and indices were selected to construct 18 model parameters. By comparing the 4 models, it was concluded that the BPNN model had the highest inversion accuracy, and its calibration coefficient of determination (R2) and root mean square error (RMSE) were 0.769 and 1.342, respectively. The validation R2 and RMSE were 0.774 and 1.975, respectively, and the relative prediction deviation (RPD) was 2.963. The SS estimation results based on BPNN model were consistent with those of the field investigation. Rapid and accurate inversion of SS based on UAV multispectral technique was achieved in this study, which provides technical support for regional management.

Excessive mechanical stress-induced intervertebral disc degeneration is related to Piezo1 overexpression triggering the imbalance of autophagy/apoptosis in human nucleus pulpous.

BACKGROUND: Mechanical stress plays a crucial role in the pathogenesis of intervertebral disc degeneration (IVDD). The mechanosensitive Piezo1 ion channel can sense the changes in mechanical stress and convert the mechanical signals into chemical signals. This study aims to investigate the effect of Piezo1 on the mechanical stress-induced IVDD and explore the possible mechanism. METHODS: The expression of Piezo1 and collagen II in immunohistochemical staining, cervical curvature, and the stiffness of nucleus pulpous (NP) were performed in normal and degenerated human intervertebral discs. In the experiment, high-intensity compression was applied to mimic the mechanical environment of IVDD. The cell viability, matrix macromolecules, and pro-inflammatory cytokines were examined to investigate the effect of Piezo1 on mechanical stress-treated NP cells. Additionally, autophagy condition of NP cells was detected within high-intensity compression and/or the inhibitor of Piezo1, GsMTx4. RESULTS: The up-expression of Piezo1, down-expression of Col II, elevated stiffness of NP, and poor kyphosis were observed in degenerated human intervertebral discs. High-intensity stress significantly decreased cell viability and the synthesis of extracellular matrix but increased the expression of senescence-associated proteins (p53 and p16) and pro-inflammatory cytokines (TNF-α, IL-6 and IL-1ß) by mitochondrial dysfunction and suppression of autophagy. However, GsMTx4 can partly attenuate these effects. CONCLUSION: Piezo1 upregulation under excessive mechanical stress promotes the apoptosis, senescence, and pro-inflammatory cytokines of NP and leads to the loss of extracellular matrix by mitochondrial dysfunction and the suppression of autophagy; on the other hand, the inhibition of Piezo1 can partly alleviate these effects.

Irisin alleviates FFA induced ß-cell insulin resistance and inflammatory response through activating PI3K/AKT/FOXO1 signaling pathway.

PURPOSE: Type 2 diabetes mellitus is characterized by insulin resistance and ß-cell dysfunction. Elevated free fatty acids-induced lipotoxicity may play a vital role in the pathogenesis of ß-cell insulin resistance. Exercise-stimulated myokine irisin has been reported to be closely related to T2DM. However, its function on ß-cell insulin signaling and the underlying mechanisms are only partially elucidated as yet. METHODS: High-fat diet-fed C57BL/6J mice and palmitic acid-treated MIN6 cell models were utilized as lipotoxic models. Factors associated with ß-cell insulin signaling transduction and inflammatory responses were assessed in these models. Furthermore, the role of irisin in ß-cells and the underlying mechanisms were also explored. RESULTS: Irisin effectively decreased lipid levels in HFD mice, enhanced glucose-stimulated insulin secretion and nullified the expressions of inflammatory cytokines in vivo and in vitro experiments. Moreover, irisin improved PI3K/AKT insulin signaling pathway and inhibited TLR4/NF-κB inflammatory signaling pathway in both islets of HFD mice and PA-treated MIN6 cells. Mechanistic analysis indicated that FOXO1 might serve as a bridge between the two pathways. CONCLUSION: Irisin alleviates lipotoxicity-induced ß-cell insulin resistance and inflammatory response through the activation of PI3K/AKT/FOXO1 signaling pathways and the inhibition of TLR4/NF-κB signaling pathways. Irisin might provide a novel therapeutic strategy for T2DM.