Rui Jin

Heihe Watershed Allied Telemetry Experimental Research (HiWATER): Scientific Objectives and Experimental Design

A major research plan entitled “Integrated research on the ecohydrological process of the Heihe River Basin” was launched by the National Natural Science Foundation of China in 2010. One of the key aims of this research plan is to establish a research platform that integrates observation, data management, and model simulation to foster twenty-first-century watershed science in China. Based on the diverse needs of interdisciplinary studies within this research plan, a program called the Heihe Watershed Allied Telemetry Experimental Research (HiWATER) was implemented. The overall objective of HiWATER is to improve the observability of hydrological and ecological processes, to build a world-class watershed observing system, and to enhance the applicability of remote sensing in integrated ecohydrological studies and water resource management at the basin scale. This paper introduces the background, scientific objectives, and experimental design of HiWATER. The instrumental setting and airborne mission plans a...

A Nested Ecohydrological Wireless Sensor Network for Capturing the Surface Heterogeneity in the Midstream Areas of the Heihe River Basin, China

This letter introduces the ecohydrological wireless sensor network (EHWSN), which we have installed in the middle reach of the Heihe River Basin. The EHWSN has two primary objectives: the first objective is to capture the multiscale spatial variations and temporal dynamics of soil moisture, soil temperature, and land surface temperature in the heterogeneous farmland; and the second objective is to provide a remote-sensing ground-truth estimate with an approximate kilometer pixel scale using spatial upscaling. This ground truth can be used for validation and evaluation of remote-sensing products. The EHWSN integrates distributed observation nodes to achieve an automated, intelligent, and remote-controllable network that provides superior integrated, standardized, and automated observation capabilities for hydrological and ecological processes research at the basin scale.

Japanese Encephalitis Virus Activates Autophagy as a Viral Immune Evasion Strategy

In addition to manipulating cellular homeostasis and survivability, autophagy also plays a crucial role in numerous viral infections. In this study, we discover that Japanese encephalitis virus (JEV) infection results in the accumulation of microtubule-associated protein 1 light chain 3-II (LC3-II) protein and GFP-LC3 puncta in vitro and an increase in autophagosomes/autolysosomes in vivo. The fusion between autophagosomes and lysosomes is essential for virus replication. Knockdown of autophagy-related genes reduced JEV replication in vitro, as indicated by viral RNA and protein levels. We also note that JEV infection in autophagy-impaired cells displayed active caspases cleavage and cell death. Moreover, we find that JEV induces higher type I interferon (IFN) activation in cells deficient in autophagy-related genes as the cells exhibited increased phosphorylation and dimerization of interferon regulatory factor 3 (IRF3) and mitochondrial antiviral signaling protein (MAVS) aggregation. Finally, we find that autophagy is indispensable for efficient JEV replication even in an IFN-defective background. Overall, our studies provide the first description of the mechanism of the autophagic innate immune signaling pathway during JEV infection.

Changes in the near-surface soil freeze–thaw cycle on the Qinghai-Tibetan Plateau

Abstract Changes in the near-surface soil freeze–thaw cycle on the Qinghai-Tibetan Plateau (QTP) were detected using daily soil freeze/thaw states derived from Special Sensor Microwave/Imager data from 1988 to 2007. Linear trends in freeze and thaw dates, the number of total frozen days of each pixel, and the numbers of monthly and yearly frozen days averaged over the whole QTP were analyzed. Principal component analysis was used to investigate the spatial variation in the freeze–thaw cycle. The results show that on the QTP there was a trend toward earlier onset date of soil thaw by approximately 14 days, and later onset date of soil freeze by approximately 10 days over the period 1988–2007. The number of frozen days has decreased over the QTP by 16.8 days per decade. This decrease in the number of frozen days has occurred mainly from April to September, with a more pronounced trend in warmer months. The most significant changes were in the northeastern and southwestern QTP, where discontinuous permafrost, island permafrost, and seasonally frozen ground are presented. The northwestern QTP had almost no change, where permafrost is cold and stable. The trend in the near-surface soil freeze–thaw cycle is positively related with climate warming on the QTP. Much warmer winters may account for significantly earlier thawing, later freezing, and a substantial reduction in the number of frozen days on the QTP. These changes in the near-surface soil freeze–thaw cycle can be used both as an effective indicator of the permafrost change and for mapping of permafrost stability. Changes in near-surface soil freeze–thaw cycle and consequently permafrost conditions would have dramatic influence on hydrologic processes, ecosystem, and engineering operations over the QTP.

Glacier area changes in the Pumqu river basin, Tibetan Plateau, between the 1970s and 2001

Glacier area changes in the Pumqu river basin, Tibetan Plateau, between the 1970s and 2001 are analyzed, based on the Chinese Glacier Inventory and ASTER images. A new glacier inventory is obtained by visually interpreting the remote-sensing images and the digital elevation model. By comparing the two inventories, glacier area changes over the past 30 years are revealed. The results show that the area loss is about 9.0% and the shrinkage trend continues according to the meteorological data.

Hybrid Optimal Design of the Eco-Hydrological Wireless Sensor Network in the Middle Reach of the Heihe River Basin, China

The eco-hydrological wireless sensor network (EHWSN) in the middle reaches of the Heihe River Basin in China is designed to capture the spatial and temporal variability and to estimate the ground truth for validating the remote sensing productions. However, there is no available prior information about a target variable. To meet both requirements, a hybrid model-based sampling method without any spatial autocorrelation assumptions is developed to optimize the distribution of EHWSN nodes based on geostatistics. This hybrid model incorporates two sub-criteria: one for the variogram modeling to represent the variability, another for improving the spatial prediction to evaluate remote sensing productions. The reasonability of the optimized EHWSN is validated from representativeness, the variogram modeling and the spatial accuracy through using 15 types of simulation fields generated with the unconditional geostatistical stochastic simulation. The sampling design shows good representativeness; variograms estimated by samples have less than 3% mean error relative to true variograms. Then, fields at multiple scales are predicted. As the scale increases, estimated fields have higher similarities to simulation fields at block sizes exceeding 240 m. The validations prove that this hybrid sampling method is effective for both objectives when we do not know the characteristics of an optimized variables.

Macromolecular crowding converts the human recombinant PrPC to the soluble neurotoxic β-oligomers

Prion diseases are fatal neurodegenerative disorders and are linked with the conversion of the cellular isoform of the prion protein (PrPc) into the abnormal β‐sheet‐rich isoform. It is widely accepted that the soluble oligomers of β‐PrP are neurotoxic and that they are more pathologically significant. To unravel the molecular mechanism under the conversion process, it is critical to identify the factors that can promote the conversion from PrPc to the β‐oligomers. By recording circular dichroism spectra and performing a size‐exclusion HPLC assay, we found that the conformation of the recombinant human prion protein (rPrPc) was converted from an α‐helical conformation into β‐sheet oligomers under a macromolecular crowding condition. The soluble β‐oligomers of rPrP were resistant to proteinase K digestion and could bind to the dyes thioflavin T and 8‐anilino‐1‐naphthalene sulfonate. Furthermore, by the 3‐(4, 5‐dimethylthiazol‐2‐yl)‐5‐(3‐carboxymethoxyphenyl)‐2‐(4‐sulfophenyl)‐2H‐tetrazolium assay, we showed that the soluble β‐oligomers were neurotoxic. These results suggest that macromolecular crowding, which has not been considered before, is a key intracellular factor in the formation of soluble neurotoxic β‐oligomers in prion diseases.—Huang, L., Jin, R., Li, J., Luo, K., Huang, T., Wu, D., Wang, W., Chen, R., Xiao, G. Macromolecular crowding converts the human recombinant PrPc to the soluble neurotoxic β‐oligomers. FASEB J. 24, 3536–3543 (2010). www.fasebj.org

Reticulon 3 attenuates the clearance of cytosolic prion aggregates via inhibiting autophagy.

Autophagy plays an important role in targeting cellular proteins, protein aggregates and organelles for degradation for cell survival. Autophagy dysfunction has been extensively described in neurodegenerative conditions linked to protein misfolding and aggregation. However, the role of autophagy in the prion disease process is unclear. Here, we show that when expressed in mouse neuroblastoma N2a cells, cytoplasmic PrP (cyPrP) aggregates lead to endoplasmic reticulum stress (ER stress), activation of reticulon 3 (RTN3), impairment of ubiquitin-proteasome system (UPS), induction of autophagy and apoptosis. RTN3 belongs to the reticulon family with the highest expression in the brain and RTN3 is often activated under ER stress. To assess the function of RTN3 in pathological conditions involving cyPrP protein misfolding, we knocked down the expression of RTN3 in cyPrP-transfected cells; unexpectedly, the inhibition of expression of RTN3 enhances the induction of autophagy resulted from cyPrP aggregates, and the process is mediated by the enhanced interaction between Bcl-2 and Beclin1 promoted by RTN3, which enhances Bcl-2-mediated inhibition of Beclin 1-dependent autophagy. Furthermore, down-regulation of RTN3 promoted the clearance of cyPrP aggregates, allowed the activity of the UPS to resume and alleviated ER stress; ultimately, apoptosis due to the cyPrP aggregates was inhibited. Together, these data suggest that RTN3 negatively regulates autophagy to block the clearance of cyPrP aggregates and provide a clue regarding the potential to induce autophagy for the treatment of prion disease and other neurodegenerative diseases such as Parkinson disease (PD), Alzheimer disease (AD) and Huntington disease (HD).

Estimating the spatial distribution of soil moisture based on Bayesian maximum entropy method with auxiliary data from remote sensing

Abstract Soil moisture (SM) plays a fundamental role in the land–atmosphere exchange process. Spatial estimation based on multi in situ (network) data is a critical way to understand the spatial structure and variation of land surface soil moisture. Theoretically, integrating densely sampled auxiliary data spatially correlated with soil moisture into the procedure of spatial estimation can improve its accuracy. In this study, we present a novel approach to estimate the spatial pattern of soil moisture by using the BME method based on wireless sensor network data and auxiliary information from ASTER (Terra) land surface temperature measurements. For comparison, three traditional geostatistic methods were also applied: ordinary kriging (OK), which used the wireless sensor network data only, regression kriging (RK) and ordinary co-kriging (Co-OK) which both integrated the ASTER land surface temperature as a covariate. In Co-OK, LST was linearly contained in the estimator, in RK, estimator is expressed as the sum of the regression estimate and the kriged estimate of the spatially correlated residual, but in BME, the ASTER land surface temperature was first retrieved as soil moisture based on the linear regression, then, the t-distributed prediction interval (PI) of soil moisture was estimated and used as soft data in probability form. The results indicate that all three methods provide reasonable estimations. Co-OK, RK and BME can provide a more accurate spatial estimation by integrating the auxiliary information Compared to OK. RK and BME shows more obvious improvement compared to Co-OK, and even BME can perform slightly better than RK. The inherent issue of spatial estimation (overestimation in the range of low values and underestimation in the range of high values) can also be further improved in both RK and BME. We can conclude that integrating auxiliary data into spatial estimation can indeed improve the accuracy, BME and RK take better advantage of the auxiliary information compared to Co-OK, and BME outperforms RK by integrating the auxiliary data in a probability form.

Regression Kriging-Based Upscaling of Soil Moisture Measurements From a Wireless Sensor Network and Multiresource Remote Sensing Information Over Heterogeneous Cropland

The ground truth estimated by in situ measurements is important for accurately evaluating retrieved remote sensing products, particularly over heterogeneous land surfaces. This letter analyzes the role of multisource remote sensing observations on the upscaling of soil moisture observed by a wireless sensor network at the pixel scale via the regression kriging (RK) method. Three types of auxiliary remote sensing information are employed, including Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) Temperature Vegetation Dryness Index (TVDI; 90 m), Polarimetric L-band Multiband Radiometer brightness temperature (700 m), and Moderate Resolution Image Spectroradiometer TVDI (1000 m). Moreover, a comparison with the ordinary kriging method is analyzed. The spatial inferences show that the RK method is more accurate and that its spatial pattern is more consistent with the auxiliary data when the trend is successfully removed, particularly when spatial continuity is destroyed by irrigation. The ASTER TVDI has a higher resolution and stronger correlation with soil moisture and yields more accurate interpolation results than the other types of remote sensing information. Although medium-resolution data do not substantially contribute to capture the spatial patterns of soil moisture, such data may still improve the prediction accuracy.