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This paper addresses the impulsive stabilization problem for a class of time-delay systems in the presence of input disturbances. A novel impulsive control law is constructed, which is based on the discrete-time equivalent control design technique. The sliding-mode-based impulsive control law allows counteracting the disturbance effect using its previous step value. To adapt in real time to the variation in sampling periods, the sliding function is designed as a function of impulse interval. Piecewise Lyapunov functions based on the partition on the maximum impulse interval are introduced to deal with the time-varying structure of the sliding function. Sufficient conditions for exponential input-to-state stability (EISS) of the impulsively controlled systems are derived, in which the EISS gain characterizes the attenuation ability of the proposed impulsive control law on the disturbance estimation error. The disturbance attenuation performance of the proposed impulsive control strategy is demonstrated through the time-delay Chua's circuit. [ABSTRACT FROM AUTHOR]

The potential of forward osmosis (FO) for water treatment can only be maximized with appropriate FO membranes. In this work, novel FO membranes functionalized with hydrophilic materials carrying both amine and sulfonate or carboxylate groups were synthesized via amidation reaction occurred on thin film composite (TFC) FO membranes. The performance of the newly explored FO membranes was evaluated in FO desalination and antifouling studies. Significant improvement in FO performance was observed for the novel FO membranes, in which the water flux increases more than 19% for the sodium taurine (ST) modified membrane (ST-modified membrane) relative to the pristine TFC FO membrane when pure water and 0.5–2.0 M MgCl 2 as the respective feed and draw solutions. Meanwhile, the ST-modified membrane produced a water flux 33% higher than that by the pristine TFC FO membrane in seawater (3.5 wt% NaCl) desalination with 2.0 M MgCl 2 as the draw solution, drastically increasing water recovery efficiency. The water flux decline of the ST-modified membrane is 46% lower than that of the pristine membrane with sodium alginate as a foulant. Introducing sulfonate or carboxylate ionic groups onto FO membrane surface is crucial to enhance the membrane antifouling ability and thus improves FO performance, which provides new insight in novel FO membrane exploration. [ABSTRACT FROM AUTHOR]

Hepatic fibrosis is a reversible scarring response that commonly occurs with chronic liver injury. During hepatic fibrogenesis, the major effector hepatic stellate cells (HSCs) become activated, featured by disappeared intracellular lipid droplets, decreased retinoid storage, and dysregulated expression of genes associated with lipid and retinoid metabolism. Compelling evidence suggested that recovery of retinoid droplets could inhibit HSC activation, while the precise molecular basis underlying the phenotypical switch still remained unclear. In this study, curcumin increased the abundance of lipid droplets and content of triglyceride in activated HSCs. In addition, curcumin could concentration-dependently regulate genes associated with lipid and retinoid metabolism. Further, consistent results were obtained from in vivo experiments. Curcumin increased Nrf2 expression and nuclear translocation, and its binding activity to DNA, which might be associated with suppression of Kelch-like ECH-associated protein 1 in HSCs. Of interest was that Nrf2 overexpression plasmids, in contract to Nrf2 siRNA, strengthened the effect of curcumin on induction of lipocyte phenotype. In in vivo system, Nrf2 knockdown mediated by Nrf2 shRNA lentivirus not only accelerated the lipid degradation in HSCs but also promoted the progression of CCl 4 -induced hepatic fibrosis in mice. Noteworthily, Nrf2 knockdown abolished the protective effect of curcumin. In conclusion, curcumin could induce lipocyte phenotype of activated HSCs via activating Nrf2. Nrf2 could be a target molecule for antifibrotic strategy. [ABSTRACT FROM AUTHOR]

Reducing the folding size of antennas, battery panels, and other structures is of great significance for the transportation of spacecraft. At present, the deployed–folded ratio of deployable structures do not satisfy the requirements of space engineering. By analysing the folding process of the flasher type, we established a mathematical model for multi-unit flat membrane folding. The deployed–folded ratio of this folding method can be higher than 70. The correctness of the mathematical model was proven through an origami example. Two folding methods for parabolic membranes were designed based on the folding of a flat membrane. We then established mathematical models of the two parabolic membrane folding methods. The accuracy of the model was verified. The errors of these mathematical models were also analysed and stated. The geometry and motion of the system of flat membrane folding and parabolic membrane folding were studied to reveal the actual folding incompatibility during motion. The models provide a reliable basis for the design of space structures. • By analysing the folding process of the flasher type, a mathematical model for flat membrane folding was established. • Two folding methods for parabolic membranes were designed based on the folding of a flat membrane. • The mathematical models of the two parabolic membrane folding methods were established and verified. [ABSTRACT FROM AUTHOR]

Habitat use by wild animals may be subject to spatial and temporal changes. The Kalamaili Mountain Ungulate Nature Reserve (KNR), inhabited by >80 % of Chinese khulan (Equus hemionus), is one of the most important desert ungulate reserves in Northwestern China. However, frequent human disturbance caused by mining development and road construction in KNR has interfered with or completely blocked their movement and access to parts of the reserve. In our study, we assessed the distribution of suitable habitat and ecological corridors of khulan before the mining development (2005), at the peak of mining development (2011), and after ecological restoration and expressway construction (2019). The results showed that most of the core habitat and ecological corridors of khulan were concentrated in the middle of the reserve and on the east side of the road. The habitat of khulan in KNR went from a good natural habitat in 2005 to deterioration due to mining development in 2011. Then it partially recovered due to ecological restoration from 2015 onwards. However, in 2019, road construction likely hindered its recovery to pre-mining levels. The location of corridors accordingly varied with the change of core habitat in different years. Nevertheless, the corridors intersecting roads generally had higher centrality values, indicating their higher importance. Our study revealed the significant impacts that mining development and road construction have had on the distribution of core habitats, ecological corridors, and movement of khulan. These results provide a scientific basis and valuable arguments for strengthening habitat connectivity for khulan. [ABSTRACT FROM AUTHOR]

An accurate and detailed determination of the status of offshore wind farms (OWFs) is crucial for offshore wind energy development, assessment, and management. However, existing OWF maps have several knowledge gaps, and it is difficult to keep these maps up-to-date over large sea areas. To address these issues, the North Sea and surrounding waters were selected as a case study, and a visual saliency detection (VSD) algorithm was developed, based on time-series of multi-source optical satellite images, to determine the status of offshore wind turbines (OWTs) (i.e. their locations and installation dates). A total of 4277 OWTs were detected in 71 OWFs in the North Sea and surrounding waters, as of July 2018, with an overall accuracy of 97.98%, a commission error rate of 1.69%, and an omission error rate of 0.33%. Besides, a proliferation of OWFs was observed in the North Sea and surrounding waters using time-series satellite monitoring, with an average annual growth rate of 22.99% during the past decade (2008–2018). Furthermore, the proposed VSD algorithm was applied to assess offshore wind energy utilisation and to map the global distribution of 6166 OWTs in 131 OWFs. This study contributes in providing a robust and cost-efficient framework for investigating OWFs over a large sea area. To the best of our knowledge, this is the first spatiotemporally-detailed inventory of OWFs, which will complement official databases. Moreover, it provides a reference for assessing the potential impact of active and decommissioned OWFs in marine ecosystems. • Time-series satellite images were used to determine the status of offshore wind farms (OWF). • A spatiotemporally-detailed inventory of OWFs in the North Sea was established. • The detection results were applied to the assessment of offshore wind energy resources. • The method was extended to derive an up-to-date distribution of global OWFs. • Multi-source sensors can be easily incorporated into the visual saliency detection (VSD) algorithm. [ABSTRACT FROM AUTHOR]

Coastal wetland vegetation is crucial for providing multiple ecosystem services. However, accurate assessment of wetland vegetation is problematic due to the challenging coastal environment. Using Xiangshan Bay (XB) in China as a typical case study, we developed a time series biological phenological approach to classifying coastal wetland vegetation using Landsat time-series images from 1984 to 2018. The results demonstrate that the total vegetation area of coastal wetlands in XB in 2018 was ~85.3 km2. The interannual dynamics of coastal wetland vegetation area in XB in the last 35 years can be divided into three periods: increasing volatility (1984–1998), decreasing (1999–2004), and increasing volatility (2005–2018). Our results emphasize the potential of the use of the time-series biological phenological approach for monitoring coastal wetland vegetation, which can contribute to the sustainable management of coastal ecosystems. • A time-series biological phenological approach can discriminate the vegetation of coastal wetlands. • Spatial distribution of coastal wetland vegetation in Xiangshan Bay in 2018 • Temporal variations of coastal wetland vegetation from 1984 to 2018 • A management scheme for the coastal zone based on vegetation changes is explored. [ABSTRACT FROM AUTHOR]

Abstract Carboxylate-functionalized imidazolium ionic liquids (CFIMILs) were synthesized via a one-pot quaternization reaction and serve as draw solutes for the first time for forward osmosis (FO) desalination. It provides a solution to simultaneously overcome the problems plaguing the use of pressure-driven membrane technologies to extract water from saline water – low water recovery efficiency and high reverse solute diffusion. The CFIMILs contain a substituted 5-membered imidazole ring and fully ionize into ionic species in water. These characteristics endow CFIMILs with capability of high water recovery efficiency and minimal reverse diffusion in FO. Sodium salt of 1-acetate-2,3-dimethyl imidazole ionic liquid (IL-1) at 0.8 M produces water fluxes of 63.6 LMH (PRO mode) and 29.5 LMH (FO mode) against the DI water feed, greatly outperforming conventional NaCl draw solute and other synthetic draw solutes. Efficient water recovery is achieved using IL-1 for seawater desalination with a water flux 5 times higher than that of NaCl. Particularly, CFIMILs draw solutes have negligible reverse diffusion in FO and are recycled completely via an MD process with good reproducibility when reused to FO, demonstrating great potentials of CFIMILs as a new class of draw solutes for FO water treatment. Highlights • Carboxylate-functionalized imidazolium ionic liquids (CFIMILs) were synthesized via a one-pot quaternization reaction. • CFIMILs served as draw solutes for seawater desalination through membrane process. • Efficient water recovery and insignificant solute loss were achieved for CFIMILs in desalination. • CFIMILs can be recycled completely and reused with good reproducibility. [ABSTRACT FROM AUTHOR]

Highlights: [•] The goitred gazelle lived in western China, has rut-induced hypophagia for males. [•] They tend to maximum their energy intake when they are not engaged in rut-related behaviors. [•] For male goitred gazelle, standing is more important in rutting season. [ABSTRACT FROM AUTHOR]

Quantifying the utilization of wildlife crossing structures (CSs) requires considering the local population background. This study assessed the effectiveness of 22 CSs based on the abundance of two ungulates (khulan and goitered gazelle) in northwestern China and analyzed variables influencing their usage such as openness, water source, and human activities in drylands. Results showed that there were 7 and 13 CSs with higher performance indices (PRi) for khulan and goitered gazelle, respectively. Khulan favors CSs near water sources and with large openness, while goitered gazelle prefers structures that include ponding and also feature large openness. Factors like distance to the CSs of the railway, predators, and human activities affect the utilization of CSs by goitered gazelle. This study emphasized the importance of designing and managing effective wildlife CSs by focusing on openness and water resources. It is recommended that CSs can be spatially consistent in multiple transportation lines run parallel. [ABSTRACT FROM AUTHOR]

Hepatocyte necroptosis is a core pathogenetic event during alcoholic liver disease. This study was aimed to explore the potential of tetramethylpyrazine (TMP), an active hepatoprotective ingredient extracted from Ligusticum Wallichii Franch, in limiting alcohol-triggered hepatocyte necroptosis and further specify the molecular mechanism. Results revealed that TMP reduced activation of receptor-interacting protein kinase 1 (RIPK1)/RIPK3 necrosome in ethanol-exposed hepatocytes and phosphorylation of mixed-lineage kinase domain-like protein (MLKL), which thereby diminished necroptosis and leakage of damage-associated molecular patterns. Suppression on mitochondrial translocation of p-MLKL by TMP contributed to recovery of mitochondrial function in ethanol-damaged hepatocytes. TMP also disrupted necroptotic signal loop by interrupting mitochondrial reactive oxygen species (ROS)-dependent positive feedback between p-MLKL and RIPK1/RIPK3 necrosome. Further, TMP promoted clearance of impaired mitochondria in ethanol-incubated hepatocytes via restoring PINK1/parkin-mediated mitophagy. Ubiquinol-cytochrome c reductase core protein 2 (UQCRC2) was downregulated in ethanol-exposed hepatocytes, which was restored after TMP treatment. In vitro UQCRC2 knockdown lowered the capacities of TMP in reducing mitochondrial ROS accumulation, relieving mitochondria damage, and enhancing PINK1/parkin-mediated mitophagy in ethanol-exposed hepatocytes. Analogously, systematic UQCRC2 knockdown interrupted the actions of TMP to trigger autophagic signal, repress necroptotic signal, and protect against alcoholic liver injury, inflammation, and ROS overproduction. In conclusion, this work concluded that TMP rescued UQCRC2 expression in ethanol-challenged hepatocytes, which contributed to necroptosis inhibition by facilitating PINK1/parkin-mediated mitophagy. These findings uncovered a potential molecular pharmacological mechanism underlying the hepatoprotective action of TMP and suggested TMP as a promising therapeutic candidate for alcoholic liver disease. [Display omitted] • TMP diminishes ethanol-caused hepatocyte necroptosis. • TMP reduces MLKL-dependent mitochondrial dysfunction in ethanol-exposed hepatocytes. • TMP reduces mitochondrial ROS to block necroptosis. • TMP clears impaired mitochondria via PINK1/parkin-mediated mitophagy. • TMP inhibits ethanol-elicited hepatocyte necroptosis via UQCRC2-mediated mitophagy. [ABSTRACT FROM AUTHOR]

Gel polymer electrolytes (GPEs) have emerged as a highly promising alternative to conventional liquid electrolytes for stable lithium-metal batteries (LIBs). However, their inherent poor mechanical properties and limited interfacial compatibility with lithium metal usually lead to unexpected growth of lithium dendrites, hindering commercial viability. Herein, an asymmetric polymer electrolyte with h-BN (HGPE) as protective layer was fabricated via a facile one-step coating strategy. Compared to pure GPE, the asymmetric polymer electrolytes exhibit significantly enhanced mechanical strength from 4.4 MPa to 7.4 MPa, effectively suppressing lithium dendrite growth. Furthermore, the HGPE improves interfacial compatibility with the anodes by preventing direct contact between GPE and lithium metals. The addition of h-BN also enhances the lithium-ion transfer number (t Li+), reaching 0.87 compared to 0.53 for pure GPE, attributed to the hindrance of anion movement by the protective layer. Consequently, the Li symmetric battery assembled with HGPE demonstrate exceptional long-term stability, maintaining performance over 1600 h at 0.1 mA cm−2. Furthermore, the assembled Li|LiFePO 4 battery can deliver a high-capacity retention rate of 93.8 % after 500 cycles at room temperature, showcasing the promising potential of asymmetric polymer electrolytes for high-performance LMBs. [Display omitted] • Polymer electrolyte with h-BN as protective layer is proposed. • The h-BN layer enhances the mechanical strength and improves the t Li + to 0.87. • The h-BN layer contributes to the formation of SEI and inhibit Li dendrite growth. • Li.|Li cells exhibit stable cyclability at 0.1 mA cm−2 over 1600 h. • Li.|LFP batteries have a high-capacity retention of 93.8 % at 2C after 500 cycles. [ABSTRACT FROM AUTHOR]

Abstract: We access the abundance of Xinjiang ground jay near the Taklimakan Desert Highway in Northwestern China, and also we used alert distance and flight initiation distance to evaluate the effects of the Taklimakan Desert Highway on Xinjiang ground jay responses to human encroachment. The results showed that Xinjiang ground jay were more abundant adjacent to the roadway than further way, and the alert distance and flight initiation distance of the Xinjiang ground jay decreased significantly with increasing road effect. These results indicated that the Taklimakan Desert Highway and its shelter forest attracted more Xinjiang ground jay to live near the road, and also the highway significantly affected the bird’s vigilance behavior. [Copyright &y& Elsevier]

Anaerobic digestion of the heavy metal-contaminated rice straw inoculated with waste activated sludge was carried out through an orthogonal array. The results indicated that the digestion process was optimized with an inoculum to substrate ratio (I/S) of 0.25, a total solid (TS) content of 5%, and an initial pH of 7.0, with corresponding total biogas and methane yields of 745.4 and 285.2 mL/g VS, respectively. Under the optimized conditions, the bioleaching percentages of Cd and As in the biomass were 13.13% and 42.90%, respectively. According to range analysis, the biogas yield, methane yield, and bioleaching percentages of Cd and As in the biomass significantly decreased with an increase in TS content from 5% to 15%. The results suggested that anaerobic digestion with waste activated sludge was feasible for achieving both biogas production and bioleaching of heavy metals from contaminated rice straw. [ABSTRACT FROM AUTHOR]

Accurate mapping of burned areas (BAs) is essential for post-disaster reconstruction, air quality assessment, and estimation of fire emissions. Remote sensing has become the most practical means to map global/regional BAs. Space-borne coarse-resolution (250–1000 m) BA products play an essential role in fire-related science and applications, but small BAs are typically poorly represented due to resolution limitations. Moderate-resolution (10–30 m) imagery provides a more detailed spatial extent of BAs, but the various disturbances (e.g., plant phenology, cloud shading, flooding, harvesting, grazing, pests, and diseases) make application on a global scale challenging. Here, we propose an automatic BA detection algorithm based on time series images acquired by the Sentinel-2 MultiSpectral Instrument (MSI) and the Google Earth Engine. Specifically: (i) We determined an optimal set of spectral indices for MSI images based on global sampling to mitigate the background heterogeneity and BA spectral diversity. (ii) We jointly used three temporal scales, i.e., the single-temporal, dual-temporal, and short-time series MSI images, to identify potential BA regions (i.e., BA candidates). (iii) We integrated multi-source active fire (AF) products derived from the Moderate-resolution Imaging Spectroradiometer (MODIS), Visible Infrared Imaging Radiometer Suite (VIIRS), Operational Land Imager (OLI), and MSI instead of single-source products to refine BA candidates. (iv) We constructed an interannual time series to improve the BA candidates not confirmed by AF products. The proposed BA detection method was applied to different land cover and regional scales, including forests, grasslands, savannas, shrublands, and croplands at the regional (scene) and national levels (Portugal). Validation and inter-comparison with similar products demonstrated that the proposed method is reliable: the Dice coefficient of our detection results was improved by ∼7% and ∼ 9%, respectively, compared to the moderate-resolution BA products (e.g., LBA_CU for the conterminous United States and FireCCISFD20 for sub-Saharan Africa in 2019). These results suggest that the proposed method can accurately and automatically map BAs, providing a foundation for fire monitoring programs and climate change research. • An automated method for detecting burned areas (BAs) was presented. • An optimal set of spectral indices was determined based on global sampling. • Interannual and short-period MSI time series were constructed to detect BAs. • Multi-source active fire products were jointly used to mitigate lookalikes. • The proposed algorithm performs well at various types of land cover. [ABSTRACT FROM AUTHOR]

A series of novel magnetic nanoparticles (MNPs) with various sizes for forward osmosis (FO) applications were synthesized via a one-pot reaction under mild conditions. The newly developed MNPs are coated with three different hydroacids (citric acid, oxalic acid and EDTA) carrying abundant carboxylic groups which could make the hydroacid-MNPs highly dispersible and ionizable in water. These features enable the aqueous solutions of hydroacid-MNPs to produce osmotic pressures and FO water fluxes comparable to the traditional draw solutions yet with a negligible reverse flux. The experimental results indicate that better FO performance was achieved when the hydroacid-MNPs with smaller sizes were applied to the FO process. With the model seawater of 3.5 wt% NaCl as the feed solution, the citric acid coated MNPs produced a water flux of 8.5 LMH, which is much higher than those reported for MNPs draw solutes applied in FO for seawater desalination. Additionally, the hydroacid-MNPs were readily regenerated from their diluted solutions after FO via an integrated system including both magnetic and membrane separations. This study significantly extends the potential applicability of FO and provides an economical approach for efficient seawater desalination via hydroacid-MNPs promoted FO processes. [ABSTRACT FROM AUTHOR]

Autophagy is a genetically programmed, evolutionarily conserved catabolic process that occurs in response to stress. While short-lived proteins are degraded via the ubiquitin/proteasome pathway in higher eukaryotes, autophagy refers to intracellular pathway for development, differentiation, survival, and homeostasis through the lysosomal-dependent machinery, which regulates the synthesis, degradation, and recycling of long-lived proteins and even whole cytoplasmic organelles. The newly discovery shows that autophagy plays an important role in recycling nutrients upon starvation and maintaining cellular energy homeostasis. Recent basic and clinical investigations further demonstrate that autophagic abnormalities have been considered underlying reasons for lots of human diseases, including liver disease, cardiovascular and cerebrovascular diseases, neurodegenerative diseases, neoplastic diseases, and cancers. Pharmacological modulation of autophagy might point to possible therapeutic strategies for combating a broad range of diseases. Regrettably, although the mechanisms underlying the regulation of autophagy have long been attracted extensive concern of numerous scholars and its acute regulation by nutrient-sensing signaling pathways is well described, the overview on longer-term transcriptional regulation of autophagy is still filled with confusion. This review summarizes current knowledge on transcriptional regulation of autophagy and expands our horizons on the autophagy repertoire. On the other hand, it also offers a glimpse into different strategies that have been used in experimental models to counteract excessive pathological autophagy via transcriptional regulation mechanism in the prevention and treatment of disease. [ABSTRACT FROM AUTHOR]

In this paper, a bismuth-doped fiber amplifier based on bismuth-aluminum-fluorine co-doping fiber is numerically simulated. The amplifier is a three-energy level structure with pump and signal wavelengths of 980 nm and 1150 nm. The different pump powers, signal powers, doping concentrations, and pump structures are adopted to investigate the effects on the gain and noise figure of the amplifier. Moreover, limited experimental results are utilized here to verify the applicability of the three-energy amplification system model to the bismuth-doped fiber amplifier (BDFA). The results show that the signal received a gain of more than 25 dB at a pump power of 500 mW for a signal input power of − 10 dBm under the forward pumping scheme, while the noise figure is around 3.2 dB. The forward pumping under the same conditions does not show a significant disadvantage compared to the bidirectional pumping, and the gain is only 1.6 % lower than the latter. In addition, the experimental results of single-mode BDFA still fit the three-energy system amplifier simulation model to some extent. The analysis supplies a positive reference for the development of amplifiers near 1150 nm, which has potential applications in medical or astronomical fields. [ABSTRACT FROM AUTHOR]

Abstract: Coated solvent impregnated resins (CSIRs) had been prepared by the formation of PVA–boric acid protective layer on solvent impregnated resins (SIRs) containing 2-ethylhexyl phosphoric acid mono (2-ethylhexyl) ester (EHEHPA). The CSIRs were characterized by scanning electron microscopy, thermogravimetric analysis and FTIR analysis. The adsorption behavior for indium (III) was carried out with the CSIRs by batch and column method. Various parameters affecting the adsorption of indium (III) such as solution pH, ionic strength, contact time, indium ion concentration and flow rate were studied, respectively. The optimal pH for the adsorption of indium ion was found to be 1.5 in the sulfuric acid system. The indium (III) loaded on CSIRs could be effectively eluted by hydrochloric acid solution (0.5–2.0molL−1), and the recovery was over 98.9%. The sorption isotherms were found to fit with Langmuir and Freundlich isotherms, respectively. The kinetics data indicated that the adsorption process of indium (III) with CSIRs followed Lagergren first order rate model. Separation of indium (III) from binary solution was also carried out successfully. The performance of the CSIRs nearly remained constant while the uncoated solvent impregnated resins (UCSIRs) rapidly lost the capacity after seven times recycling. [Copyright &y& Elsevier]

In this paper, the gain and noise characteristics of bismuth-doped fiber amplifiers in O-band (1260–1360 nm) under forward, backward and bidirectional pumping are comprehensively compared and optimized using numerical models. The validity of the model is verified. The results show that (1)the signal power is changed within a limited range does not have an effect on the noise figure. However, the noise figure will be worse while the power continues to increase, and the magnitude of the change is most pronounced under the backward pumping scheme. With an increase in signal power from − 25 dBm to − 10 dBm, the noise figure is relatively flat under all pumping schemes. While increasing from − 10–0 dBm, the noise figure under backward pumping increased by 0.9 dB; (2)Only if pump power is below a certain threshold, the gain obtained under bidirectional scheme is significantly higher than under forward and backward.With larger pump power, the gain obtained under all pumping schemes is almost the same. With pump power less than 1.2 W, the gain under bidirectional scheme is 0.9 dB higher than that under forward and backward schemes. With more than 1.2 W, the gain difference between bidirectional and forward and backward is only 0.2 dB. The analysis provides guidance for the selection and optimization of pumping structures in BDFA, thus helping to improve the performance of O-band transmission systems. [ABSTRACT FROM AUTHOR]

River networks are important water carriers that provide a multitude of ecosystem services, including freshwater for agriculture, drinking water for cities, and recreational activities. Accurate mapping of river networks from remote-sensing images is important for the study of these systems. Unfortunately, the delineation of river networks is challenging due to the meandering nature of river channels, the often complex and variable features of the surrounding landscape, and the spatial heterogeneity of the river networks. Here, we present an adaptive, multi-scale region growth method (AMRGM) to delineate river networks from sentinel-2A/B MSI images. The method can handle variable river heterogeneous surroundings, multiple spatial scales, and variable curvatures of the river channels. The method includes four steps: (1) a water index (NDWI) is used to provide initial detection of river water pixels in the image; (2) a bias-corrected fuzzy C-means (BCFCM) method alleviates the effects of the variable surrounding landscape; (3) a scale-enhancement algorithm based on the hessian matrix makes full use of scale and direction information to enhance river morphology characteristics (multiple dimensions and variable curvatures), and (4) a regional growth criterion facilitates handling of various river dimensions. Fast-growing and fine-screening strategies are also included in the AMRGM. The method is applied to eight river networks to evaluate its accuracy and reliability with various river morphologies and hydrological conditions. The AMRGM is more widely applicable than four commonly used river-detection methods (i.e., K-means method, maximum likelihood method, iterative self-organizing data analysis technique algorithm, and support vector machine) and outperform these methods when detecting multi-scale river branches. The mean overall accuracy (OA) and kappa coefficients (KC) of the AMRGM exceed 97% and 0.92 across the eight river networks. The most accurate river extractions are obtained for large rivers such as the Amazon River, Mackenzie River, and Ganges River Delta, which have more discernable scale and direction characteristics. Relatively high omission and commission errors are observed in river networks with complex and heterogeneous zonations, such as the river Welland, UK, and the Zagya Zangbo River in the Tibet plateau. The complex geomorphic features of the river Welland reduce OA and KC to 93.8% and 0.86, respectively • A method is proposed for extracting river networks from MSI images. • Background homogenization and adaptive multi-scale region growth are adopted. • The proposed method is sensitive to multiple scales of river networks. • The strategy of "fast-growing and fine-screening" is used. [ABSTRACT FROM AUTHOR]