Search

Background/Objectives: Osteoarthritis (OA) is a prevalent degenerative disease globally, characterized by cartilage degradation and joint dysfunction. Current treatments are insufficient for halting OA progression. Irigenin (IRI), a flavonoid extracted from natural plants with anti-inflammatory and antioxidant properties, has demonstrated potential in mitigating inflammation and oxidative stress in various diseases; however, its effects on OA remain unexplored. This study aims to evaluate the therapeutic effects of IRI on OA through in vivo and in vitro experiments and to elucidate the underlying molecular mechanisms. Methods: In vitro, chondrocytes were exposed to hydrogen peroxide (H2O2) to induce an oxidative stress environment and were then treated with IRI. Western blotting, RT-qPCR, immunofluorescence staining assays, flow cytometry, and apoptosis assays were employed to assess the effects of IRI on chondrocyte matrix homeostasis, inflammatory response, and apoptosis. In vivo, an OA rat model was treated with regular IRI injections, and therapeutic effects were evaluated using micro-CT, histological staining, and immunohistochemistry assays. Results: IRI treatment restored matrix homeostasis in chondrocytes and effectively suppressed H2O2-induced inflammation and apoptosis. Subsequent studies further revealed that IRI exerts its therapeutic effects by activating the Nrf2/HO-1 pathway. Inhibition of Nrf2 expression in chondrocytes partially blocked the anti-inflammatory and antioxidant effects of IRI. In the OA rat model, regular IRI injections effectively ameliorated cartilage degeneration. Conclusions: This study identifies IRI as a promising strategy for OA treatment by modulating inflammation and apoptosis through the Nrf2/HO-1 pathway. [ABSTRACT FROM AUTHOR]

MXenes nanosheets with high conductivity, hydrophilicity, and excellent reactive oxygen species (ROS) scavenging ability have shown promise in treating various degenerative diseases correlated with abnormal ROS accumulation. Herein, the therapeutic potential of Ti3C2Tx nanosheets, which is the most widely investigated MXene material, in delaying osteoarthritis (OA) progression is demonstrated. In vitro experiments indicate the strong ROS scavenging capacity of Ti3C2Tx nanosheets and their acceptable biocompatibility. Ti3C2Tx nanosheets effectively protect chondrocytes from cell death induced by oxidative stress. In addition, Ti3C2Tx nanosheets demonstrate a prominent anti-inflammatory effect and the ability to restore homeostasis between anabolic activities and catabolic activities in chondrocytes. Furthermore, RNA sequencing reveals the potential mechanism underlying the Ti3C2Tx nanosheet-mediated therapeutic effect. Finally, the in vivo curative effect of Ti3C2Tx nanosheets is verified using a rat OA model. Histological staining and immunohistochemical analyses indicate that Ti3C2Tx nanosheets effectively ameliorate OA progression. Conclusively, the in vitro and in vivo experiments suggest that Ti3C2Tx nanosheets could be a promising and effective option for OA treatment. [ABSTRACT FROM AUTHOR]

Forward jammers replicate and retransmit radar signals back to generate coherent jamming signals and false targets, making anti-jamming an urgent issue in electronic warfare. Jamming transmitters work at saturation to maximize the retransmission power such that only the phase information of the angular waveform at the designated direction of arrival (DOA) is retained. Therefore, amplitude modulation of MIMO radar angular waveforms offers an advantage in combating forward jamming. We address both the design of unimodular MIMO waveforms and their associated mismatch filters to confront mainlobe jamming in this paper. Firstly, we design the MIMO waveforms to maximize the discrepancy between the retransmitted jamming and the spatially synthesized radar signal. We formulate the problem as unconstrained non-linear optimization and solve it using the conjugate gradient method. Particularly, we introduce fast Fourier transform (FFT) to accelerate the numeric calculation of both the objection function and its gradient. Secondly, we design a mismatch filter to further suppress the filtered jamming through convex optimization in polynomial time. The simulation results show that for an eight-element MIMO radar, we are able to reduce the correlation between the angular waveform and saturated forward jamming to −6.8 dB. Exploiting this difference, the mismatch filter can suppress the jamming peak by 19 dB at the cost of an SNR loss of less than 2 dB. [ABSTRACT FROM AUTHOR]

Volumetric-based pricing for irrigation water was introduced as part of a comprehensive reform of agricultural water prices in China. However, operational deficiencies and farmers' lack of willingness to adopt the volumetric pricing policy (VPP) hinder the coordinated implementation of the reform. To address these practical challenges, we employed a binary logistic regression model to analyse farmers' acceptance of the VPP for agricultural irrigation water usage in Suqian City, Jiangsu Province. A variable set was formed by selecting potential variables from four types of influencing factors: the subject (water users), the object (water supply departments), natural condition factors, and social condition factors. Our results revealed seven factors that determine whether farmers accept the VPP: irrigation water measurement at the water inlet of a lateral canal, the irrigation water-saving rewards scale, enforcement efforts of charging by volume, the irrigation water source type, the use of agricultural water-saving for trade, financial investment in water-saving technology, and the level of irrigation water pricing. We determined the degree of influence of the seven determining factors, among which the irrigation water-saving rewards scale and enforcement efforts of charging by volume most influence farmers' decisions on the VPP for irrigation water. The results of this study can be used as a reference for innovation of the agricultural water-saving system in Suqian City, optimisation of an accurate fiscal subsidy scale, quantification of irrigation water rights, optimisation of the measurement facility layout, and effective implementation of agricultural water rights trading. More broadly, this study provides a valuable reference for solving the difficulties faced in the comprehensive reform of agricultural water pricing in China, which includes irrigation water pricing mechanisms, management systems, subsidy mechanisms, and water-saving incentive measures. [ABSTRACT FROM AUTHOR]

To address the most significant environmental challenges, the quest for high-performance gas sensing materials is crucial. Among numerous two-dimensional materials, this study investigates the gas-sensitive capabilities of monolayer As, Sb, and Bi materials. To compare the gas detection abilities of these three materials, we employ first-principles calculations to comprehensively study the adsorption behavior of NO and NO2 gas molecules on the material surfaces. The results indicate that monolayer Bi material exhibits reasonable adsorption distances, substantial adsorption energies, and significant charge transfer for both NO and NO2 gases. Therefore, among the materials studied, it demonstrates the best gas detection capability. Furthermore, monolayer As and Sb materials exhibit remarkably high capacities for adsorbing NO and NO2 gas molecules, firmly interacting with the gas molecules. Gas adsorption induces changes in the material's work function, suggesting the potential application of these two materials as catalysts. [ABSTRACT FROM AUTHOR]

The ACTN2 gene encodes α-actinin 2, located in the Z-disc of the sarcomeres in striated muscle. In this study, we sought to investigate the effects of an ACTN2 missense variant of unknown significance (p.A868T) on cardiac muscle structure and function. Left ventricular free wall samples were obtained at the time of cardiac transplantation from a heart failure patient with the ACTN2 A868T heterozygous variant. This variant is in the EF 3–4 domain known to interact with titin and α-actinin. At the ultrastructural level, ACTN2 A868T cardiac samples presented small structural changes in cardiomyocytes when compared to healthy donor samples. However, contractile mechanics of permeabilized ACTN2 A868T variant cardiac tissue displayed higher myofilament Ca2+ sensitivity of isometric force, reduced sinusoidal stiffness, and faster rates of tension redevelopment at all Ca2+ levels. Small-angle X-ray diffraction indicated increased separation between thick and thin filaments, possibly contributing to changes in muscle kinetics. Molecular dynamics simulations indicated that while the mutation does not significantly impact the structure of α-actinin on its own, it likely alters the conformation associated with titin binding. Our results can be explained by two Z-disc mediated communication pathways: one pathway that involves α-actinin's interaction with actin, affecting thin filament regulation, and the other pathway that involves α-actinin's interaction with titin, affecting thick filament activation. This work establishes the role of α-actinin 2 in modulating cross-bridge kinetics and force development in the human myocardium as well as how it can be involved in the development of cardiac disease. [ABSTRACT FROM AUTHOR]

Strain engineering is an effective way to adjust the sensing properties of two-dimensional materials. In this paper, lateral heterojunctions (LHSs) based on arsenic and antimony have been designed along the armchair (AC) or zigzag (ZZ) edges. The adsorption and sensing characteristics of As/Sb LHSs to NO2 before and after applying different types of strain are calculated by first principles. The band gaps of all As/Sb heterostructures are contributed by As-p and Sb-p orbitals. In addition, the adsorption energy of As/Sb ZZ-LHS with −4% compression strain is the largest. Furthermore, its work function changes significantly before and after the adsorption of NO2. Meanwhile, strong orbital hybridizations near the Fermi level are observed and a new state is yielded after applying compressive strain. These results indicate that the As/Sb LHS with ZZ interface under −4% compression strain possesses the best sensing properties to NO2. This work lays the foundation for the fabrication of high-performance NO2 gas sensors. High-performance gas sensors can be used to track and regulate NO2 exposure and emission, as well as to track NO2 concentrations in the atmosphere and support the assessment of air quality. [ABSTRACT FROM AUTHOR]

Traffic congestion is a typical phenomenon when motorways meet urban road networks. At this special location, the weaving area is a recurrent traffic bottleneck. Numerous research activities have been conducted to improve traffic efficiency and sustainability at bottleneck areas. Variable speed limit control (VSL) is one of the effective control strategies. The primary objective of this paper is twofold. On the one hand, turbulent traffic flow is to be smoothed on the special weaving area of motorways and urban roads using VSL control. On the other hand, another control method is provided to tackle the carbon dioxide emission problem over the network. For both control methods, a multi-agent reinforcement learning algorithm is used (MAPPO: multi-agent proximal policy optimization). The VSL control framework utilizes the real-time traffic state and the speed limit value in the last control step as the input of the optimization algorithm. Two reward functions are constructed to guide the algorithm to output the value of the dynamic speed limit enforced within the VSL control area. The effectiveness of the proposed control framework is verified via microscopic traffic simulation using simulation of urban mobility (SUMO). The results show that the proposed control method could shape a more homogeneous traffic flow, and reduces the total waiting time over the network by 15.8%. In the case of the carbon dioxide minimization strategy, the carbon dioxide emission can be reduced by 10.79% in the recurrent bottleneck area caused by the transition from motorways to urban roads. [ABSTRACT FROM AUTHOR]

Agricultural terraces are important artificial landforms on the Loess Plateau of China and have many ecosystem services (e.g., agricultural production, soil and water conservation). Due to the loss of rural labor, a large number of agricultural terraces have been abandoned and then the degradation of terraces, caused by rainstorm and lack of management, threatens the sustainability of ecological services on terraces. Our previous study has found its geomorphological evidence (sinkhole and collapse). However, no quantitative indicators of terrace degradation are identified from the perspective of microtopography change. A framework for quantifying terrace degradation was established in this study based on unmanned aerial vehicle photogrammetry and digital topographic analysis. The Pujiawa terraces in the Loess Plateau were selected as study areas. Firstly, the terrace ridges were extracted by a Canny edge detector based on high-resolution digital elevation model (DEM) data. The adaptive method was used to calculate the low and high thresholds automatically. This method ensures the low complexity and high-edge continuity and accuracy of the Canny edge detector, which is superior to the manual setting and maximum inter-class variance (Otsu) method. Secondly, the DEMs of the terrace slope before degradation were rebuilt through the terrain analysis method based on the extracted terrace ridges and current DEM data. Finally, the degradation of terraces was quantified by the index series in the line, surface and volume aspects, which are the damage degrees of the terrace ridges, terrace surface and whole terrace. The damage degrees of the terrace ridges were calculated according to the extracted and generalised terrace ridges. The damage degrees of the terrace surface and whole terrace were calculated based on the differences of DEMs before and after degradation. The proposed indices and quantitative methods for evaluating agricultural terrace degradation reflect the erosion status of the terraces in topography. This work provides data and references for loess terrace landscape protection and its sustainable management. [ABSTRACT FROM AUTHOR]

Desired retention and depth into wood are necessary for wood preservatives to provide long-term durability. In general, heartwood of wood is difficult to treat, and bioincising was investigated as a potential technique to improve the treatability of refractory wood and heartwood. In order to study the effects of bioincising treatment with white-rot fungus Trametes versicolor on the pore structure and treatability of radiata pine heartwood, this research conducted tests of mass loss, microscopic structures, pore structure parameters, uptake, and penetration of preservative of radiata pine heartwood specimens incubated by T. versicolor for 4, 8, and 12 weeks. The results showed that the optimal inoculation time of T. versicolor bioincising on radiata pine heartwood was 4 to 8 weeks. At this time, the retention of injected preservatives increased by 5.01%–17.73%, the penetration depth of preservatives increased significantly, and the corresponding mass loss was 3.04%–6.45%. The results of microstructure and pore structure showed that T. versicolor entered the adjacent tracheids via apertures, with less impact on the cell wall, mainly degrading pit membranes and ray parenchyma cells early in the inoculation of radiata pine heartwood. As the structures impeding fluid flow were connected, the porosity of the wood and the range of the main pore size distribution increased significantly, thus increasing the treatability of radiata pine heartwood. [ABSTRACT FROM AUTHOR]

Previous studies have suggested that the sodium alginate (SA) is beneficial for the treatment of non-alcoholic fatty liver disease (NAFLD), while the potential mechanisms are largely unknown. The present study aimed to clarify the effects and potential mechanisms of SA in preventing NAFLD via the gut−liver axis. Thirty-two male Sprague−Dawley rats were randomly divided into four groups: normal control group (NC); high-fat diet group (HFD); HFD with 50 mg/kg/d sodium alginate group (LSA); HFD with 150 mg/kg/d sodium alginate group (HSA). After 16 weeks, the rats were scarified to collect blood and tissues. The results indicated that SA significantly reduced their body weight, hepatic steatosis, serum triglyceride (TG), alanine transaminase (ALT) and tumor necrosis factor α (TNF-α) levels and increased serum high-density lipoprotein-cholesterol (HDL-C) levels in comparison with HFD group (p < 0.05). The elevated mRNA and protein expression of genes related to the toll-like receptor 4 (TLR-4)/nuclear factor-kappa B (NF-κB)/nod-like receptor protein 3 (NLRP3) inflammatory signaling pathway in the liver of HFD-fed rats was notably suppressed by SA. In terms of the gut microbiota, the LSA group showed a significantly higher fecal abundance of Oscillospiraceae_UCG_005, Butyricicoccaceae_UCG_009 and Colidextribacter compared with the HFD group (p < 0.05). The rats in the HSA group had a higher abundance of unclassified_Lachnospiraceae, Colidextribacter and Oscillibacter compared with the HFD-associated gut community (p < 0.05). In addition, rats treated with SA showed a significant increase in fecal short chain fatty acids (SCFAs) levels and a decline in serum lipopolysaccharide (LPS) levels compared with the HFD group (p < 0.05). Moreover, the modulated bacteria and microbial metabolites were notably correlated with the amelioration of NAFLD-related indices and activation of the hepatic TLR4/NF-κB/NLRP3 pathway. In conclusion, SA prevented NAFLD and the potential mechanism was related to the modulation of the gut–liver axis. [ABSTRACT FROM AUTHOR]

The distribution of glycerol dialkyl glycerol tetraethers (GDGTs) in carbonate-type and sulfate-type saline lacustrine sediments from the Ordos Plateau in China is investigated to explore the influence of ionic composition on GDGTs. In general, they are relatively small (1.2–6.0 km2 surface area) and shallow ponds (0.05–0.2 m water depth) and even seasonally dry lakes. The results reveal that the concentration of GDGTs has a good positive correlation with the (nCO32− + nHCO3−)/total ions, and the concentration of GDGTs in carbonate-type lake sediments is significantly higher than that in sulfate-type lake sediments. Most GDGT-based indices show no significant differences, and the distributions of GDGTs are similar in the two types of saline lake sediments. The lack of a positive correlation between the content of clay minerals and the concentration of GDGTs may imply that the ability of clay minerals to carry terrigenous organic matter is very limited in arid climates. The branched GDGTS (brGDGTs) in the two saline lake sediments may mainly come from in situ biological production and have low terrestrial inputs. The different weathering level of feldspar minerals in the two types of saline lakes results in the difference in organic matter content, which ultimately affects the concentration of GDGTs. [ABSTRACT FROM AUTHOR]

In recent years, rare-earth metals with triply oxidized state, lanthanide ions (Ln3+), have been demonstrated as dopants, which can efficiently improve the optical and electronic properties of metal halide perovskite materials. On the one hand, doping Ln3+ ions can convert near-infrared/ultraviolet light into visible light through the process of up-/down-conversion and then the absorption efficiency of solar spectrum by perovskite solar cells can be significantly increased, leading to high device power conversion efficiency. On the other hand, multi-color light emissions and white light emissions originated from perovskite nanocrystals can be realized via inserting Ln3+ ions into the perovskite crystal lattice, which functioned as quantum cutting. In addition, doping or co-doping Ln3+ ions in perovskite films or devices can effectively facilitate perovskite film growth, tailor the energy band alignment and passivate the defect states, resulting in improved charge carrier transport efficiency or reduced nonradiative recombination. Finally, Ln3+ ions have also been used in the fields of photodetectors and luminescent solar concentrators. These indicate the huge potential of rare-earth metals in improving the perovskite optoelectronic device performances. [ABSTRACT FROM AUTHOR]

There is consensus in industry and academia that Highly Automated Vehicles (HAV) and Connected Automated Vehicles (CAV) will be launched into the market in the near future due to emerging autonomous driving technology. In this paper, a mixed traffic simulation framework that integrates vehicle models with different automated driving systems in the microscopic traffic simulation was proposed. Currently, some of the more mature Automated Driving Systems (ADS) functions (e.g., Adaptive Cruise Control (ACC), Lane Keeping Assistant (LKA), etc.) are already equipped in vehicles, the very next step towards a higher automated driving is represented by Level 3 vehicles and CAV which show great promise in helping to avoid crashes, ease traffic congestion, and improve the environment. Therefore, to better predict and simulate the driving behavior of automated vehicles on the motorway scenario, a virtual test framework is proposed which includes the Highway Chauffeur (HWC) and Vehicle-to-Vehicle (V2V) communication function. These functions are implemented as an external driver model in PTV Vissim. The framework uses a detailed digital twin based on the M86 road network located in southwestern Hungary, which was constructed for autonomous driving tests. With this framework, the effect of the proposed vehicle models is evaluated with the microscopic traffic simulator PTV Vissim. A case study of the different penetration rates of HAV and CAV was performed on the M86 motorway. Preliminary results presented in this paper demonstrated that introducing HAV and CAV to the current network individually will cause negative effects on traffic performance. However, a certain ratio of mixed traffic, 60% CAV and 40% Human Driver Vehicles (HDV), could reduce this negative impact. The simulation results also show that high penetration CAV has fine driving stability and less travel delay. [ABSTRACT FROM AUTHOR]

An indirect method for monitoring dynamic deflection of beam-like structures using strain responses measured by long-gauge fiber Bragg grating (FBG) sensors is proposed in this paper. Firstly, a theoretical derivation shows that structural deflection is in direct and linear relationship to long-gauge strain. Meanwhile, the method is suitable for structures with different boundary conditions and irrelevant to external loads. Secondly, the influence of boundary conditions, load type and sensor gauge length on the method is investigated by numerical simulation. Finally, an experiment of a simply supported beam subjected to dynamic loads was designed to verify the method. Experimental results show that both deflection time-history of arbitrary points of structures and deflection distribution along structures at a certain time can be obtained with high-precision. Therefore, the method presented can be a new alternative for the deflection evaluation and maintenance of engineering structures. [ABSTRACT FROM AUTHOR]

The South-to-North Water Transfer Jiangsu Water Supply Area (JWSA) is a mega inter-basin water transfer area (water source) that provides water resources from JiangHuai, combines drainage and flooding management, and regulates nearby rivers and lakes. Analyzing the spatiotemporal soil moisture dynamics in the area will be informative regarding agricultural drought along with flood disaster assessment and will provide early warning studies. Therefore, we evaluated the quality of European Space Agency Climate Change Initiative Soil Moisture (ESA CCI_SM) data in the South-North Water Transfer JWSA. Furthermore, we utilized ensemble empirical modal decomposition, Mann-Kendall tests, and regression analysis to study the spatiotemporal variation in soil moisture for the past 29 years. The CCI _SM data displayed a high correlation with local soil measurements at nine sites. We next analyzed the CCI_SM data from three pumping stations (the Gaogang, Hongze, and Liushan stations) in the South-North Water Transfer JWSA. These stations had similar periodic characteristics of soil moisture, with significant periodic fluctuations around 3.1 d. The overall soil moisture at the three typical pumping stations demonstrated an increasing trend. We further investigated whether abrupt soil moisture changes existed at each station or not. The spatial distribution of soil moisture in the South-North Water Transfer JWSA was characterized as "dry north and wet south", with higher soil moisture in winter, followed by autumn, and low soil moisture in spring and summer. Although the linear trend of soil moisture in the South-North Water Transfer JWSA varied in significance, the overall soil moisture in the JWSA has increased over the past 29 years. The areas with significantly enhanced soil moisture are mostly distributed in the Yangzhou and Huai'an areas in the southeastern part of the study area. The areas with significantly decreased soil moisture are small in size and mostly located in northern Xuzhou. [ABSTRACT FROM AUTHOR]

Terraces, which are typical artificial landforms found around world, are of great importance for agricultural production and soil and water conservation. However, due to the lack of maintenance, terrace damages often occur and affect the local flow process, which will influence soil erosion. Automatic high-accuracy mapping of terrace damages is the basis of monitoring and related studies. Researchers have achieved artificial terrace damage mapping mainly via manual field investigation, but an automatic method is still lacking. In this study, given the success of high-resolution unmanned aerial vehicle (UAV) photogrammetry and object-based image analysis (OBIA) for image processing tasks, an integrated framework based on OBIA and UAV photogrammetry is proposed for terrace damage mapping. The Pujiawa terrace in the Loess Plateau of China was selected as the study area. Firstly, the segmentation process was optimised by considering the spectral features and the terrains and corresponding textures obtained from high-resolution images and digital surface models. The feature selection was implemented via correlation analysis, and the optimised segmentation parameter was achieved using the estimation of scale parameter algorithm. Then, a supervised k-nearest neighbourhood classifier was used to identify the terrace damages in the segmented objects, and additional geometric features at the object level were considered for classification. The comparison with the ground truth, as delineated by the image and field survey, showed that proposed classification can be adequately performed. The F-measures of extraction on three terrace damages were 92.07% (terrace sinkhole), 81.95% (ridge sinkhole), and 85.17% (collapse), and the Kappa coefficient was 85.34%. Finally, the potential application and spatial distribution of the terrace damages in this study were determined. We believe that this work can provide a credible framework for mapping terrace damages in the Loess Plateau of China. [ABSTRACT FROM AUTHOR]

As a small-molecule reductant substance, hydrogen gas has an obvious antioxidant function. It can selectively neutralize hydroxyl radicals (•OH) and peroxynitrite (ONOO•) in cells, reducing oxidative stress damage. The purpose of this study was to investigate the effect of hydrogen gas (3%) on early chronic liver injury (CLI) induced by CCl4 and to preliminarily explore the protective mechanism of hydrogen gas on hepatocytes by observing the expression of uncoupling protein 2 (UCP2) in liver tissue. Here, 32 rats were divided into four groups: the control group, CCl4 group, H2 (hydrogen gas) group, and CCl4 + H2 group. The effect of hydrogen gas on early CLI was observed by serological tests, ELISA, hematoxylin and eosin staining, and oil red O staining. Immunohistochemical staining and Western blotting were used to observe the expression of UCP2 in liver tissues. We found that CCl4 can induce significant steatosis in hepatocytes. When the hydrogen gas was inhaled, hepatocyte steatosis was reduced, and the UCP2 expression level in liver tissue was increased. These results suggest that hydrogen gas might upregulate UCP2 expression levels, reduce the generation of intracellular oxygen free radicals, affect lipid metabolism in liver cells, and play a protective role in liver cells. [ABSTRACT FROM AUTHOR]

Low-dimensional GaAs photodetectors have drawn a great deal of attention because of their unique absorption properties and superior responsivity. However, their slow response speed caused by surface states presents challenges. In this paper, a mixed-dimensional GaAs photodetector is fabricated utilizing a single GaAs nanowire (NW) and a GaAs 2D non-layer sheet (2DNLS). The photodetector exhibits a fast response with a rise time of ~4.7 ms and decay time of ~6.1 ms. The high-speed performance is attributed to an electron transmission channel at the interface between the GaAs NW and GaAs 2DNLS. Furthermore, the fast electron channel is confirmed by eliminating interface states via wet passivation. This work puts forward an effective way to realize a high-speed photodetector by utilizing the surface states of low-dimensional materials. [ABSTRACT FROM AUTHOR]

As a typical wide bandgap semiconductor, ZnO has received a great deal of attention from researchers because of its strong physicochemical characteristics. During the past few years, great progress has been made in the optoelectronic applications of ZnO, particularly in the photocatalysis and photodetection fields. To enable further improvements in the material's optoelectronic performance, construction of a variety of ZnO-based composite structures will be essential. In this paper, we review recent progress in the growth of different ZnO–graphene nanocomposite structures. The related band structures and photocatalysis and photoresponse properties of these nanocomposites are discussed. Additionally, specific examples of the materials are included to provide an insight into the common general physical properties and carrier transport characteristics involved in these unique nanocomposite structures. Finally, further directions for the development of ZnO–graphene nanocomposite materials are forecasted. [ABSTRACT FROM AUTHOR]

More and more attention has been paid to farmland water conservancy project (FWCP) maintenance in China, which can reallocate water resources in a more rational and efficient manner. Compared with the traditional survey such as field survey, FWCP maintenance can be improved efficiently with geospatial technology. To improve the level of FWCP maintenance in China, a collaborative sensing system framework by integrating satellite, aerial, and ground remote sensing is put forward. The structure of the system framework includes three sections, namely the data acquisition, the operational work, and the application and service. Through the construction and operation of such collaborative sensing system, it will break through the limitation of any single remote sensing platform and provide all-around and real-time information on FWCP. The collaborative monitoring schemes for the designed FWCP maintenance can engage ditch riders to maintain more effectively, which will enable them to communicate more specifically with smallholders in the process of irrigation. Only when ditch riders and farmers are fully involved, irrigation efficiency will be improved. Furthermore, the collaborative sensing system needs feasible standards for multi-source remote sensing data processing and intelligent information extraction such as data fusion, data assimilation, and data mining. In a way, this will promote the application of remote sensing in the field of agricultural irrigation and water saving. On the whole, it will be helpful to improve the traditional maintenance problems and is also the guarantee for establishing a long-term scientific management mechanism of FWCP maintenance in developing countries, especially in China. [ABSTRACT FROM AUTHOR]

The investigation of photodetectors with broadband response and high responsivity is essential. Zinc Oxide (ZnO) nanowire has the potential of application in photodetectors, owing to the great optoelectrical property and good stability in the atmosphere. However, due to a large number of nonradiative centers at interface and the capture of surface state electrons, the photocurrent of ZnO based photodetectors is still low. In this work, 2D Bi2Se3/ZnO NWAs heterojunction with type-I band alignment is established. This heterojunction device shows not only an enhanced photoresponsivity of 0.15 A/W at 377 nm three times of the bare ZnO nanowire (0.046 A/W), but also a broadband photoresponse from UV to near infrared region has been achieved. These results indicate that the Bi2Se3/ZnO NWAs type-I heterojunction is an ideal photodetector in broadband detection. [ABSTRACT FROM AUTHOR]

Photocatalytic water splitting into hydrogen is regarded as one of the key solutions to the deterioration of the global environment and energy. Due to the significantly reduced grain boundaries, ZnO nanorods facilitate a fast electron transfer through their smooth tunnels and are well suited as a photocatalyst. However, the photocatalytic hydrogen evolution performance of pristine ZnO nanorods is still low due to the high recombination rate of photogenerated electron-hole pairs and the less light absorption. Here, a novel structure about black ZnO nanorods (NRs)/TiO2-X mesoporous spheres (MSs) heterojunction has been prepared and the photocatalytic hydrogen evolution performance has been explored. The photocatalytic activity test results showed that ZnO NRs/TiO2-X MSs exhibited higher catalytic activity than ZnO NRs for hydrogen production. Compared to the pure ZnO NRs photoanode, the photocurrent of ZnO NRs/TiO2-X MSs heterojunction photoanode could reach 0.41 mA/cm2 in view of the expanding spectral response region and effective inhibition of e−/h+ recombination at the same condition. Using a relatively integrated experimental investigation and mechanism analysis, we scrutinized that after being treated with NaBH4, TiO2 MSs introduce oxygen vacancies expanding the photocatalytic activity of pure TiO2, and improving conductivity and charge transport capabilities through coating on ZnO NRs. More importantly, the results provide a promising approach in the NRs/MSs composite structure serving as photoanodes for photocatalytic hydrogen production. [ABSTRACT FROM AUTHOR]

GaAs has been demonstrated to be a promising material for manufacturing semiconductor light-emitting devices and integrated circuits. It has been widely used in the field of aerospace, due to its high electron mobility and wide band gap. In this study, the structural and photoelectric characteristics of Si-doped GaAs under different gamma irradiation doses (0, 0.1, 1 and 10 KGy) are investigated. Surface morphology studies show roughen of the surface with irradiation. Appearance of transverse-optical (TO) phonon mode and blueshift of TO peak reflect the presence of internal strain with irradiation. The average strain has been measured to be 0.009 by Raman spectroscopy, indicating that the irradiated zone still has a good crystallinity even at a dose of 10 KGy. Photoluminescence intensity is increased by about 60% under 10 KGy gamma irradiation due to the strain suppression of nonradiative recombination centers. Furthermore, the current of Si-doped GaAs is reduced at 3V bias with the increasing gamma dose. This study demonstrates that the Si-doped GaAs has good radiation resistance under gamma irradiation, and appropriate level of gamma irradiation can be used to enhance the luminescence property of Si-doped GaAs. [ABSTRACT FROM AUTHOR]

Gullies of different scales and types have developed in the Loess Plateau, China. Differences in the amount of gully erosion influence the development, evolution, morphology, and spatial distribution of these gullies. The strengths of headward erosion on the gully shoulder line are used to dictate soil and water conservation measures. In this study, six typical loess landforms in the Loess Plateau were selected as sampling sites: Shenmu, Suide, Ganquan, Yanchuan, Yijun, and Chunhua, which respectively represent loess–aeolian and dune transition zones, loess hills, loess ridge hills, loess ridges, loess long-ridge fragmented tablelands, and loess tablelands. Using 5 m resolution digital elevation model data from the National Basic Geographic Information Database, a small representative watershed was selected from each sampling site to obtain elevation data on the terrain profiles of gully shoulder lines. Multifractal detrended fluctuation analysis (MF-DFA) was used to conduct statistical and comparative analysis of the elevation fluctuation characteristics of these profiles. The results show that MF-DFA is capable of detecting active gully erosion sites. Sites of active gully erosion are concentrated in Shenmu and Suide but more widely distributed in the other five sites. The results provide a scientific basis for small watershed management planning and the design of soil and water conservation measures. [ABSTRACT FROM AUTHOR]

Silicon carbide (SiC) has been widely used for electronic radiation detectors and atomic battery sensors. However, the physical properties of SiC exposure to high-dose irradiation as well as its related electrical responses are not yet well understood. Meanwhile, the current research in this field are generally focused on electrical properties and defects formation, which are not suitable to explain the intrinsic response of irradiation effect since defect itself is not easy to characterize, and it is complex to determine whether it comes from the raw material or exists only upon irradiation. Therefore, a more straightforward quantification of irradiation effect is needed to establish the direct correlation between irradiation-induced current and the radiation fluence. This work reports the on-line electrical properties of 4H-SiC Schottky barrier diodes (SBDs) under high-dose electron irradiation and employs in situ noise diagnostic analysis to demonstrate the correlation of irradiation-induced defects and microscopic electronic properties. It is found that the electron beam has a strong radiation destructive effect on 4H-SiC SBDs. The on-line electron-induced current and noise information reveal a self-healing like procedure, in which the internal defects of the devices are likely to be annealed at room temperature and devices' performance is restored to some extent. [ABSTRACT FROM AUTHOR]

Collimated outflows and jets play a critical role in shaping planetary nebulae (PNe), especially in the brief transition from a spherical AGB envelope to an aspherical PN, which is called the protoplanetary nebula (pPN) phase. We present UV observations of Hen 3-1475, a bipolar pPN with fast, highly collimated jets, obtained with STIS on board the Hubble Space Telescope (HST). The deep, low-dispersion spectroscopy enabled monochromatic imaging of Hen 3-1475 in different UV nebular emission lines; this is the first of such attempt ever conducted for a pPN. The northwest inner knot (NW1) is resolved into four components in Mg ii λ 2800. Through comparison analysis with the HST optical narrowband images obtained 6 yr earlier, we found that these components of NW1 hardly move, despite of a negative gradient of high radial velocities, from −1550 km s - 1 on the innermost component to ∼−300 km s - 1 on the outermost. These NW1 knot components might thus be quasi-stationary shocks near the tip of the conical outflow of Hen 3-1475. [ABSTRACT FROM AUTHOR]

Unlike conventional bulk or film materials, one-dimensional (1D) semiconducting zinc oxide (ZnO) nanostructures exhibit excellent photoelectric properties including ultrahigh intrinsic photoelectric gain, multiple light confinement, and subwavelength size effects. Compared with polycrystalline thin films, nanowires usually have high phase purity, no grain boundaries, and long-distance order, making them attractive for carrier transport in advanced optoelectronic devices. The properties of one-dimensional nanowires—such as strong optical absorption, light emission, and photoconductive gain—could improve the performance of light-emitting diodes (LEDs), photodetectors, solar cells, nanogenerators, field-effect transistors, and sensors. For example, ZnO nanowires behave as carrier transport channels in photoelectric devices, decreasing the loss of the light-generated carrier. The performance of LEDs and photoelectric detectors based on nanowires can be improved compared with that of devices based on polycrystalline thin films. This article reviews the fabrication methods of 1D ZnO nanostructures—including chemical vapor deposition, hydrothermal reaction, and electrochemical deposition—and the influence of the growth parameters on the growth rate and morphology. Important applications of 1D ZnO nanostructures in optoelectronic devices are described. Several approaches to improve the performance of 1D ZnO-based devices, including surface passivation, localized surface plasmons, and the piezo-phototronic effect, are summarized. [ABSTRACT FROM AUTHOR]

The field of piezoresistive sensors has been undergoing a significant revolution in terms of design methodology, material technology and micromachining process. However, the temperature dependence of sensor characteristics remains a hurdle to cross. This review focuses on the issues in thermal-performance instability of piezoresistive sensors. Based on the operation fundamental, inducements to the instability are investigated in detail and correspondingly available ameliorative methods are presented. Pros and cons of each improvement approach are also summarized. Though several schemes have been proposed and put into reality with favorable achievements, the schemes featuring simple implementation and excellent compatibility with existing techniques are still emergently demanded to construct a piezoresistive sensor with excellent comprehensive performance., Competing Interests: The authors declare no conflict of interest.