Quantitative estimation for the impact of mining activities on vegetation phenology and identifying its controlling factors from Sentinel-2 time series

International audienc

Ultrasound–enhanced brain delivery of edaravone provides additive amelioration on disease progression in an ALS mouse model

Background: Although amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease and unfortunately incurable yet, incremental attention has been drawn to targeting the health of corticospinal motor neurons. Focused ultrasound combined with systemically circulating microbubbles (FUS/MB) is an emerging modality capable of site-specific molecular delivery temporarily and noninvasively within a range of appropriate parameters. Objective: To investigate the effect of FUS/MB–enhanced delivery of therapeutics to the motor cortex on the disease progression by using a transgenic mouse model of ALS. Methods: Multiple FUS/MB–enhanced deliveries of Edaravone (Eda) to the motor cortex were performed on the SOD1G93A mouse model of ALS. The motor function of the animals was evaluated by gait analysis, grip strength and wire hanging tests. Corticospinal and spinal motor neuronal health, misfolded SOD1 protein and neuroinflammation after treatments were evaluated by histological examination. Results: Ultrasound–enhanced delivery of Eda in the targeted motor cortex was achieved by a two-fold increase without gross tissue damage. Compared with the ALS mice administered Eda treatments only, the animals given additionally FUS/MB–enhanced brain delivery of Eda (FUS/MB + Eda) exhibited further improvements in neuromuscular functions characterized by gait patterns, muscular strength, and motor coordination along with rescued muscle atrophy. FUS/MB + Eda treatments conferred remarkable neuroprotection to both upper and lower motor neurons revealed by normalized neuronal morphology with increasing cell body size and profoundly alleviated neuroinflammation and misfolded SOD1 protein in the brains and lumbar spinal cords. Conclusion: We report a pilot study that non-invasive ultrasound–enhanced brain delivery of Eda provides additive amelioration on disease progression of ALS and suggest that broadening the target from spinal to cortical network functions using the FUS/MB–enhanced delivery can be a rational therapeutic strategy of this debilitating disorder

LAI-Based Phenological Changes and Climate Sensitivity Analysis in the Three-River Headwaters Region

Global climate changes have a great impact on terrestrial ecosystems. Vegetation is an important component of ecosystems, and the impact of climate changes on ecosystems can be determined by studying vegetation phenology. Vegetation phenology refers to the phenomenon of periodic changes in plants, such as germination, flowering and defoliation, with the seasonal change of climate during the annual growth cycle, and it is considered to be one of the most efficient indicators to monitor climate changes. This study collected the global land surface satellite leaf area index (GLASS LAI) products, meteorological data sets and other auxiliary data in the Three-River headwaters region from 2001 to 2018; rebuilt the vegetation LAI annual growth curve by using the asymmetric Gaussian (A-G) fitting method and extracted the three vegetation phenological data (including Start of Growing Season (SOS), End of Growing Season (EOS) and Length of Growing Season (LOS)) by the maximum slope method. In addition, it also integrated Sen’s trend analysis method and the Mann-Kendall test method to explore the temporal and spatial variation trends of vegetation phenology and explored the relationship between vegetation phenology and meteorological factors through a partial correlation analysis and multiple linear regression models. The results of this study showed that: (1) the SOS of vegetation in the Three-River headwaters region is concentrated between the beginning and the end of May, with an interannual change rate of −0.14 d/a. The EOS of vegetation is concentrated between the beginning and the middle of October, with an interannual change rate of 0.02 d/a. The LOS of vegetation is concentrated between 4 and 5 months, with an interannual change rate of 0.21 d/a. (2) Through the comparison and verification with the vegetation phenological data observed at the stations, it was found that the precision of the vegetation phonology extracted by the A-G method and the maximum slope method based on GLASS LAI data is higher (MAE is 7.6 d, RMSE is 8.4 d) and slightly better than the vegetation phenological data (MAE is 9.9 d, RMSE is 10.9 d) extracted based on the moderate resolution imaging spectroradiometer normalized difference vegetation index (MODIS NDVI) product. (3) The correlation between the SOS of vegetation and the average temperature in March–May is the strongest. The SOS of vegetation is advanced by 1.97 days for every 1 °C increase in the average temperature in March–May; the correlation between the EOS of vegetation and the cumulative sunshine duration in August–October is the strongest. The EOS of vegetation is advanced by 0.07 days for every 10-h increase in the cumulative sunshine duration in August–October