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Abstract Background X-linked agammaglobulinemia (XLA), also referred to as Bruton’s tyrosine kinase deficiency, is a rare genetic disorder that affects the immune system. We conducted genetic analysis on patients suffering from immunodeficiency by utilizing Next-Generation Sequencing techniques, as well as their closest relatives, to facilitate accurate diagnosis, offer genetic counseling services, and enhance our comprehension of XLA.

Abstract The elevation gradient has long been known to be vital in shaping the structure and function of terrestrial ecosystems, but little is known about the elevation-dependent pattern of net CO2 uptake, denoted by net ecosystem productivity (NEP). Here, by analyzing data from 203 eddy covariance sites across China, we report a negative linear elevation-dependent pattern of NEP, collectively shaped by varying hydrothermal factors, nutrient supply, and ecosystem types. Furthermore, the NEP shows a higher temperature sensitivity in high-elevation environments (3000–5000 m) compared with the lower-elevation environments (

RFPA2D was used to simulate the crack propagation, failure mode, and fractal characteristics of composite strata with prefabricated cracks and holes under the uniaxial compression test. The crack propagation process was analyzed when the crack inclination angle and rock inclination angle changed. And it was concluded that: when the rock inclination angle is 0° and the crack inclination angle changes, the cracks are classified into X-type cracks and Y-type cracks. When the crack inclination angle is 0° and the rock inclination angle changes, the failure modes of the model specimens are divided into the through-cut failure mode of soft rock and the failure mode along the soft rock. The variation law of fractal dimension of cracks in the composite rock stratum with holes calculated by Matlab is the same as that of the compressive strength of the model specimen, and the fitting between fractal dimension and compressive strength has a significant linear relationship.

ABSTRACTCu(im)2-derived Cu@N–C(600) catalyst has been efficiently utilized for the preparation of N-tosyl(H)−2-substituted indoles through one-pot domino Sonogashira coupling-cyclization reactions between N-tosyl(acetyl)−2-iodo anilines and aryl acetylenes. The catalytic system was heterogeneous and showed excellent functional group compatibility and could be performed well, affording the corresponding coupling products in good to excellent yields.

Abstract Background The oncology-related indices between open and video-assisted thoracoscopic surgery (VATS) procedures for thymic carcinomas (TCs) and thymic neuroendocrine tumors (TNETs) remain unclear. Methods Propensity score matching (PSM) and multivariate Cox proportional risk models were used to evaluate the perioperative outcomes and survival rates of patients undergoing open and VATS for TCs and TNETs at the Second Affiliated Hospital of Air Force Military Medical University Hospital, between 2009 and 2018. Results Of the total 126 cases of TCs and TNETs, VATS treatment was used in 39 (30.9%). Advanced age and Masaoka-Koga staging were found to be independent prognostic factors for both TCs and TNETs, through a multifactorial Cox regression analysis. There was no significant difference in survival between the VATS and open groups before and after PSM; however, the VATS group had better perioperative-related indicators. There were no significant differences between the groups in terms of mortality at 30 days, mortality at 90 days, R0 resection rate, and 5-year survival rate (67.5% vs. 58.5% [P = 0.260] in the VATS group compared to the open group, in a PSM analysis of the 27 VATS and 27 open groups). Compared to the open group, the VATS group had a shorter length of hospital stay (13 days vs. 16 days, P = 0.015), a shorter level I care (0 days vs. 1 day, P = 0.016), and less intraoperative bleeding (50 mL vs. 300 mL, P

Introduction: Soil ciliates, as protozoa, play a crucial role in biogeochemical cycling and the soil food web, yet they are highly sensitive to environmental fluctuations in soil conditions. The diversity and biogeographic characteristics of soil ciliates in the Tibetan Plateau remain poorly understood. As part of a regional survey focused on soil ciliate diversity, we investigated the composition and spatiotemporal variations of soil ciliate communities along the Yarlung Zangbo River, a representative soil habitat in the Tibetan Plateau.Methods: A total of 290 soil samples were collected from four habitat types of grassland, shrubland, forestland and wetland in the middle reaches of the Yarlung Zangbo River during the wet and dry seasons, and 138 species of ciliates were identified.Results: Soil ciliate diversity exhibited greater variation across habitat types than seasons. Moreover, soil ciliate diversity was higher during the wet season compared to the dry season, with the wetland habitat showing the highest diversity and the grassland habitat displaying the lowest. We observed spatiotemporal heterogeneity in the composition of soil ciliate communities across different seasons and habitat types. Notably, Litostomatea, Karyorelictea, and Prostomatea predominated in ciliate communities during the wet season and in grassland habitat. Phyllopharyngers dominated during dry seasons and in forested regions, while Spirotrichea species were prevalent in wetland and forested areas. The co-occurrence network analysis showed that soil ciliate community was more complex in wet season than in dry season, and the stability of soil ciliate community in wet season was higher than that in dry season. The stability of soil ciliate community in wetland was higher than that in forestland, shrubland and grassland, and the anti-interference ability was stronger. Soil temperature (ST), Total nitrogen (TN), Soil organic matter (SOM) and Soil water content (SWC) are important factors affecting the structure of soil ciliate community. By influencing the metabolic rate and nutrient acquisition of soil ciliates, the distribution pattern of soil ciliate community diversity in the middle reaches of Yarlung Zangbo River is shaped.Discussion: In summary, this study revealed the distribution pattern of soil ciliate community diversity in the Yarlung Zangbo River Basin, and the key factors affecting the spatial and temporal differences and stability of the community, enhancing our understanding of how ciliates adapt to environmental conditions in soil habitats across the Tibetan Plateau.

Abstract Terrestrial ecosystems can exhibit various behaviors in response to climate change and human activities. Nonlinear and abrupt shifts in ecosystems are particularly important as they indicate substantial modifications in ecosystem structure and function, posing a threat to the provision of ecosystem services. Here we distinguish between linear, curvilinear, and abrupt shifts in ecosystem productivity from 2000 to 2020 in China's Loess Plateau. We utilize spatial Random Forest models to analyze the driving factors behind these change patterns. Our findings indicate that 84.1% of the ecosystems experienced a positive change in plant productivity, while a small proportion (2.5%) exhibited a negative change. Abrupt shifts are prevalent in both positive and negative changes in ecosystem productivity, with negative changes often manifesting as abrupt shifts (79.3%). Negative changes in plant productivity, particularly the negative abrupt shifts, are primarily associated with human activities characterized by increased nighttime light and urbanization. Land conversion to forest is linked to a curvilinear trajectory in plant productivity, characterized by nonlinear changes with acceleration. Higher water availability and a wetter environment are more likely to promote positive changes in plant productivity. Moderate warming trends contribute to abrupt positive changes in plant productivity, while high warming trends are associated with increased negative abrupt and curvilinear changes. We highlight the importance of accounting for diverse change behaviors in ecosystems for the development of targeted conservation and restoration measures.

Abstract Recent concurrent processes of vegetation greening and reduced resilience (the capacity to recover from disturbances) worldwide have brought many uncertainties into sustainable ecosystems in the future. However, little is known about the conditions and extent to which greening affects resilience changes. Here we assess both vegetation dynamics and resilience in China’s Loess Plateau from 2000 to 2020 using satellite-based vegetation data and an early warning indicator. Our results reveal an overall greening trend in vegetated areas, while resilience shifted from gains to losses at a breakpoint in 2010. Vegetation greening generally contributed to resilience gains, whereas increased temperature and precipitation variability contributed to the resilience loss observed in 2011–2020. These findings provide empirical evidence that vegetation greening does not necessarily correspond to an increase in resilience. We therefore recommend integrating resilience indicators into ecological restoration and conservation efforts to gain a more comprehensive understanding of vegetation states and support effective ecosystem stewardship.

Abstract The social–ecological trap is an emerging concept that describes situations in which self‐reinforcing social and ecological feedbacks maintain or push a social–ecological system towards an undesirable state and threaten the sustainability of human societies. Understanding a system's feedback loops and identifying the leading factors of such traps is essential to develop effective management strategies to warn, avoid and escape traps. To better understand the dynamics of social–ecological traps, we developed a quantitative diagnostic framework that combines the social–ecological network approach and composite system state index. We demonstrated the effectiveness of the framework by examining the rural social–ecological evolution in China's Loess Plateau (LP) from 1949 to 2020, an area once faced with severe social–ecological challenges such as soil erosion, land degradation and poverty. Our analysis identified three stages of trap dynamics in LP: locked in the trap (1949–1981), reacting to the trap (1981–2003) and escaping the trap (2003–2020). In the first stage, LP was locked into an undesirable trajectory where reinforcing feedback occurs between rapid population growth, limited livelihood opportunities, excessive reliance on agriculture and severe soil erosion. Our results also found that the LP has made significant progress in escaping this social–ecological trap during the 21st century through ecological restoration practices and socioeconomic development. Similar social–ecological traps are also observed in many other regions of the world, particularly in developing countries. Our analysis recommends three pathways for addressing social–ecological traps in the LP: (1) promoting urbanization and livelihood diversity, (2) implementing site‐specific engineering measures (e.g. terraces and check dams in the LP) and (3) investing in ecological restoration programs. Escaping the trap is not the end of the story, but could be an early stage of another trap. Policymakers and managers should keep assessing and monitoring the policy practices and outcomes to avoid entering new trap situations. Read the free Plain Language Summary for this article on the Journal blog.

Using cowhide as raw material, the process of ultrasonic-assisted enzyme extraction of collagen from cowhide was optimized. Based on the single factor experiment, a response surface test was designed, and the extraction rate of cowhide collagen was used as the response value to optimize the optimal extraction process of collagen, and its structure was characterized. The results showed that the optimal extraction conditions of collagen from cowhide were ultrasonic power 161 W, ultrasonic treatment time 64 min, pepsin addition 109 U/g, and solid-liquid ratio 1:16 g/mL. Under these conditions, the extraction rate of collagen was 63.77%. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), ultraviolet spectroscopy (UV) and Fourier transform infrared spectroscopy (FTIR) analysis showed that the collagen extracted by ultrasound-assisted enzyme was in line with the characteristics of type I collagen, maintaining its complete triple helix structure, amino acid composition and scanning electron microscope (SEM) analysis showed that the collagen triple helix extracted by ultrasonic assisted enzyme was relatively stable. In this study, an effective process is optimized for the extraction of collagen from cowhide, besides, the extraction time of collagen is greatly shortened and it has high utilization value.

Target tracking is an important research in the field of computer vision. Despite the rapid development of technology, difficulties still remain in balancing the overall performance for target occlusion, motion blur, etc. To address the above issue, we propose an improved kernel correlation filter tracking algorithm with adaptive occlusion judgement and model updating strategy (called Aojmus) to achieve robust target tracking. Firstly, the algorithm fuses color-naming (CN) and histogram of gradients (HOG) features as a feature extraction scheme and introduces a scale filter to estimate the target scale, which reduces tracking error caused by the variations of target features and scales. Secondly, the Aojmus introduces four evaluation indicators and a double thresholding mechanism to determine whether the target is occluded and the degree of occlusion respectively. The four evaluation results are weighted and fused to a final value. Finally, the updating strategy of the model is adaptively adjusted based on the weighted fusion value and the result of the scale estimation. Experimental evaluations on the OTB-2015 dataset are conducted to compare the performance of the Aojmus algorithm with four other comparable algorithms in terms of tracking precision, success rate, and speed. The experimental results show that the proposed Aojmus algorithm outperforms all the algorithms compared in terms of tracking precision. The Aojmus also exhibits excellent performance on attributes such as target occlusion and motion blur in terms of success rate. In addition, the processing speed reaches 74.85 fps, which also demonstrates good real-time performance.

Efficiently mitigating the severe air pollution resulting from rapid progress is crucial for the sustainable development of the socio-ecological system. Recently, concerns about nature-based solutions have emerged in the research on the treatment of air pollution. Studies on the purification of PM2.5 using vegetation currently concentrate on the individual scale of tree species or urban vegetation, ignoring the regional scale, which could better assist ecological governance. Therefore, taking the Fenwei Plain of China as the study area, an assessment framework of the air purification service’s spatial distribution reflecting regional vegetation was constructed. The dry deposition model and GeoDetector were used to quantify the spatial-temporal pattern and explore natural driving factors on the removal of PM2.5. The results showed that (1) the PM2.5 purification services offered by various types of vegetation exhibit notable variations. The average removal rates of PM2.5 by vegetation were 0.186%, 0.243%, and 0.435% in 2000, 2010, and 2021, respectively. (2) Meanwhile, a wide range of spatial mismatch exists between the PM2.5 concentration and PM2.5 removal. Insufficient supply regions of PM2.5 purification services account for 50% of the Fenwei Plain. (3) PM2.5 removal was strongly influenced by the types of vegetation and the Normalized Vegetation Index (NDVI), followed by the Digital Elevation Model (DEM), and less affected by meteorological factors; a strong joint effect was shown among the factors. The findings in this research provide a new perspective on regional air pollution management at the regional scale.

In recent years, with the advancement of natural language processing techniques and the release of models like ChatGPT, how language models understand questions has become a hot topic. In handling complex logical reasoning with pre-trained models, its performance still has room for improvement. Inspired by DAGN, we propose an improved DaGATN (Discourse-apperceptive Graph Attention Networks) model. By constructing a discourse information graph to learn logical clues in the text, we decompose the context, question, and answer into elementary discourse units (EDUs) and connect them with discourse relations to construct a relation graph. The text features are learned through a discourse graph attention network and applied to downstream multiple-choice tasks. Our method was evaluated on the ReClor dataset and achieved an accuracy of 74.3%, surpassing the best-known performance methods utilizing deberta-xlarge-level pre-trained models, and also performed better than ChatGPT (Zero-Shot).

As population growth and urbanization continue to accelerate, city dwellers are increasingly conscious of the demand for urban green space (UGS) and the ecosystem services (ESs) it provides. Great efforts are made for the supply of certain ESs in UGS. However, less is known about the residents’ preferences and the supply–demand matching of UGS types, as well as the various ESs it provides at different spatial scales. Given this, our research establishes a research framework to reveal the heterogeneity of USG types and the supply–demand matching degree (SDM) of ESs from municipal, provincial, and national spatial scales, and examines the correlation between the influencing factors and demands of residents for UGS. This study mainly used the Gini coefficient, the Lorenz curve, Z-scores, the Jenks natural breaks classification method, Pearson correlation analysis, and spatial analysis. The main findings are that (1) the Gini coefficients are 0.433 and 0.137 at the municipal and provincial scales, respectively, indicating that the supply of UGS is more unequal at the municipal scale than provincial scale; (2) the multi-scale demand for ESs between residents has no significant difference. At the provincial scale, the area with low demand is larger than that of high demand, while at the municipal scale, the contrary is the case; (3) the SDM was in a deficit at both the provincial and municipal scales. And as the scaling-up occurred, the spatial heterogeneity of the SDM decreased; (4) the number of influencing factors that significantly affected the UGS type and ESs grew as the scale increased. Among them, the impact of age and COVID-19 on three scales deserves attention. These results identify regions with deficits and surpluses in ESs provided by UGS in China at different scales. This research also advises that attention should be paid to the distribution of UGS between cities within provinces, and future UGS planning should focus on building regional green spaces to promote the well-being of an aging society. The findings in this study would offer insights for managers to improve UGS construction and urban forestry planning in the future.

Multi-source ecological risks have induced many ecological pollution problems that cannot be ignored and seriously threaten regional ecological security. Constructing and optimizing the landscape pattern is beneficial to improve watershed ecosystem services. In this study, an innovative method is proposed to construct and optimize the landscape pattern, which takes Luojiang-Small Creek watershed as an example. 10-meter high-precision raster elements are selected as the basic unit for landscape ecological risk evaluation, and 20 evaluation factors are selected from three dimensions of “natural environment-human society-landscape pattern” to establish the evaluation index system. The spatial principal component-redundancy analysis (SPCA-RDA) was used to comprehensively evaluate the landscape ecological risk in 2019, and the minimum cumulative resistance model (MCR) and gravity model were used to optimize the landscape pattern of the watershed. The results show (1) Human social and landscape pattern factors have a more significant influence on the integrated ecological risk, while natural factors, except for soil type and vegetation cover, have a weaker influence on the integrated ecological risk. (2) The overall landscape ecological risk is low, and the area of the mild landscape ecological risk zone is 259.89 km2, accounting for 81.68 % of the study area. According to the MCR model and gravity model, forest land with an area larger than 1 km2 and water bodies and grassland with an area larger than 0.01 km2 were identified as ecological source sites. (3) 17 potential ecological corridors were constructed, including 4 road-type corridors, 9 green belt-type corridors and 4 river-type corridors, with a total length of 68.72 km, and 22 potential ecological nodes were identified, including 8 A-type ecological nodes and 14 B-type ecological nodes. A comprehensive three-dimensional spatial ecological network of “ecological nodes-ecological corridors-ecological zones” was constructed, and the optimization effect of the landscape pattern in the study area was evaluated, and it was found that the optimized landscape pattern had significantly improved in terms of connectivity. The results of the study provide ecological protection and planning guidance for future risk prevention and control and landscape pattern optimization of the area with watershed as a unit.

Multilayer electroforming has a high potential to produce Ni/Ni layer structured metal walls with excellent material properties and a high thickness uniformity. However, Ni is easily oxidized in air, which fundamentally leads to a low adhesion strength between the Ni layers. Here, a novel in situ treatment is proposed for improving the adhesion performance between Ni layers. This treatment integrated the steps of electrochemical dissolution, surface protection, and electroforming. A study of the polarization behavior implied the electroformed Ni layer was dissolved efficiently in the NH2SO3H solution, beginning at a dissolution current density of 5 A·cm−2, which could remove the oxide film. A smooth substrate surface with a good surface hydrophilicity was obtained starting at 8 A·cm−2, helping to protect the activated substrate from being contaminated and oxidized. The experimental results showed that ultrahigh normal and shear adhesion strengths over 400 MPa between the Ni layers were achieved.

Land is an important resource that supports the production, life, and ecological development of human society. The current research on production–living–ecological space (PLES) is mainly focusing on the identification of single and dominant functions of land space, and the comprehensive spatial function measurement index of PLES (PLESI) is less known in the effective quantitative evaluation of multifunctionality of different land use categories. Integrating the CMIP6 (Coupled Model Intercomparison Project phase 6) scenario data and the future land use simulation model (FLUS), this research took the upper reaches of the Hanjiang River (URHR) as an example to explore the temporal and spatial variations in land use, PLES, and PLESIs during 2000–2020, and in the SSP2-4.5 and SSP5-8.5 scenarios from 2021 to 2100. The findings were as follows: (1) Forest land is the most widely distributed type of land; correspondingly, ecological space has the widest distribution area in PLES, followed by production space. (2) The area of dry land and building land increased between 2000 and 2010, accompanied by the increase in living space. From 2010 to 2020, the growth rate of building land tended to slow down while forest land increased, and the conflict of PLES eased. (3) The transfer between forest land and dry land is projected to intensify under the SSP2-4.5 scenario, while it is projected to occur between forest land and grassland under the SSP5-8.5 scenario. As for the changes in PLES, the SSP2-4.5 scenario has a greater impact than the SSP5-8.5 scenario. Spatially, several sub-basins in the northern URHR are the main areas of land use and PLES change. (4) PLESI presents a significant downward trend from 2000 to 2020 while trending upward under the SSP5-8.5 scenario and trending downward slightly under the SSP2-4.5 scenario between 2020 and 2100. Combining climate scenarios and the future land use simulation, this research would support the effective utilization of regional land resources and ecosystem management decision-making.

The growth habit of natural gas hydrate in formation pores directly influences its occurrence and distribution, which are fundamental factors for macroscopic reservoir properties. In order to simulate the hydrate growth at pore scale and demonstrate the growth process directly, microscopic visualization experiments were carried out using glass etching model and high-resolution video microscope in this work. The crystal growth behavior of methane hydrate was observed clearly in real time, and fluid state and system pressure were analyzed. On this basis, hydrate growth patterns and corresponding control mechanisms were investigated. The results show that for a static methane–water system, the hydrate crystal grew rapidly about 10 min after perturbation. The solution gas crystallized with water, forming colorless, transparent and polygonal crystal with sharp edge and smooth surface. The free gas crystallized with water at the gas–water interface first, resulting in a quick formation of hydrate crust. Then water passed through the hydrate crust slowly and crystallized with the free gas trapped inside hydrate crust. The resulting hydrates seemed to rough and honeycomb aggregations of tiny and tightly packed crystal particles. The two kinds of hydrate with different morphologies represent two typical hydrate growth patterns. For the hydrate growth pattern of solution gas–water, solution gas, which migrates to the crystal growth front driven by the concentration gradient, is in direct contact with water, leading to a fast crystal growth rate. For the crystal growth pattern of free gas–water, the preferentially formed hydrate crust at the gas–water interface not only separates the free gas from the water phase, but also selectively obstructs the passage of gas and only allows water to pass slowly, which slows down the hydrate growth process. This research is helpful to further understand the experimental phenomena at the core and field scale, explain the existing problems, and provide support for the research on the dissociation and exploitation of natural gas hydrate.

Background: Extensive research showed costimulatory molecules regulate tumor progression. Nevertheless, a small amount of literature has concentrated on the potential prognostic and therapeutic effects of costimulatory molecules in patients with glioma.Methods: The data were downloaded from The Cancer Genome Atlas (TCGA) database, Chinese Glioma Genome Atlas (CGGA) database, and Gene Expression Omnibus (GEO) database for bioinformatics analysis. R software was applied for statistical analysis. Using the FigureYa and Xiantao online tools (https://www.xiantao.love/) for mapping.Results: The Least absolute shrinkage and selection operator (LASSO) and Cox regression analysis were utilized to identify the signature consisting of five costimulatory molecules. Multivariate regression analysis revealed that the prognosis of glioma could be independently predicted by the riskscore. Furthermore, we explored clinical and genomic feature differences between the two groups. The level of tumor mutational burden (TMB) was higher in the high-risk group, while more mutation of IDH1 was observed in the low-risk group. Results of Tumor Immune Dysfunction and Exclusion (TIDE) analysis showed that high-risk patients were more prone to be responded to immunotherapy. In addition, subclass mapping analysis was performed to validate our findings and the results revealed that a significantly higher percentage of immunotherapy response rate was observed in the high-risk group.Conclusion: A novel signature with a good independent predictive capacity of prognosis was successfully identified. And our findings reveal that patients with high-risk scores were more likely to be responded to immunotherapy.

Summary Currently, piperazic acid is chemically synthesized using ecologically unfriendly processes. Microbial synthesis from glucose is an attractive alternative to chemical synthesis. In this study, we report the production of L‐piperazic acid via microbial fermentation with the first engineered fungal strain of Aureobasidium melanogenum; this strain was constructed by chassis development, genetic element reconstitution and optimization, synthetic rewiring and constitutive genetic circuit reconstitution, to build a robust L‐piperazic acid synthetic cascade. These genetic modifications enable A. melanogenum to directly convert glucose to L‐piperazic acid without relying on the use of either chemically synthesized precursors or harsh conditions. This bio‐based process overcomes the shortcomings of the conventional synthesis routes. The ultimately engineered strain is a very high‐efficient cell factory that can excrete 1.12 ± 0.05 g l‐1 of L‐piperazic acid after a 120‐h 10.0‐l fed‐batch fermentation; this is the highest titre of L‐piperazic acid reported using a microbial cell factory.

High Mountain Asia glaciers are currently ignored in the estimation of global greenhouse gas budgets (e.g., methane (CH4) and carbon dioxide (CO2)). Similar to the Asian Water Tower and Third Pole, the Tibetan Plateau (TP) hosts the largest volume of glaciers outside the polar regions. These glaciers contain large reservoirs of organic carbon that can influence glacial ecosystems under rapid melting. However, no data exist on the current footprint of CH4 and CO2 from glaciers in the TP. Here, we report in situ observations of CH4 and CO2 fluxes for glacial cryoconite holes, subglacial sediments, and proglacial river runoff across the TP. Our results indicate that cryoconite holes and subglacial sediments can accelerate the export of greenhouse gasses during the melting season due to intensive glacier melting. However, to some extent, proglacial river runoff can be a significant sink of atmospheric CO2; this fact was not identified in previous studies. Our findings suggest that variations (source or sink) of greenhouse gasses from TP glacial basins should be considered in regional CH4 and CO2 budgets under climate warming.

The exploitation of carbon dots (CDs) is now flourishing; however, more effort is needed to overcome their lack of intrinsic specificity. Herein, instead of synthesizing novel CDs, we reinvestigated three reported CDs and discovered that plain ammonium citrate CDs (AC-CDs) exhibited surprising specificity for Helicobacter pylori. Notably, we showed that the interfacial mechanism behind this specificity was due to the affinity between the high abundant urea/ammonium transporters on H. pylori outer membrane and the surface-coordinated ammonium ions on AC-CDs. Further, we justified that ammonium sulfate-citric acid CDs also possessed H. pylori-specificity owing to their NH4+ doping. Thereby, we suggested that the incorporation of a molecule that could be actively transported by abundant membrane receptors into the precursors of CDs might serve as a basis for developing a plain CD with intrinsic specificity for H. pylori. Moreover, AC-CDs exhibited specificity towards live, dead, and multidrug-resistant H. pylori strains. Based on the specificity, we developed a microfluidics-assisted in vitro sensing approach for H. pylori, achieving a simplified, rapid and ultrasensitive detection with two procedures, shortened time within 45.0 ​min and a low actual limit of detection of 10.0 ​CFU ​mL−1. This work sheds light on the design of more H. pylori-specific or even bacteria-specific CDs and their realistic translation into clinical practice.

Abstract In lime concretion black soil, a two-factor (tillage and irrigation) split block experiment from 2015 to 2017 was conducted to identify whether their combination is suitable for the improvement of winter wheat yield and water use efficiency. The main treatments were subsoiling (SS) and rotary tillage (RT), with secondary treatments of three irrigation regimes: no irrigation during the whole growth period (W0), irrigation at jointing stage (W1), and irrigation at both jointing and anthesis stages (W2). In combination with a soil column experiment, the contribution of the root system in different soil layers to yield was clarified. The results indicated that both tillage and irrigation significantly influenced the spatiotemporal distributions of the root systems and yield components, while tillage produced the strongest effect. Compared with RT, SS significantly promoted the root penetration and delayed root senescence in deep soil layers. With increasing soil depth, each root configuration parameter (dry root weight density, DRWD; root length density, RLD; root surface area per unit area, RSA; root volume per unit area, RV) gradually decreased, and the peak appearance times of each root parameter in RT and three parameters (RLD, RSA and RV) in SS were postponed from heading to anthesis and from anthesis to filling stage, respectively. The average post-peak attenuation values at soil layers from 60 to 100 cm in W1 were less than those in W0 and W2. SSW1 generated the highest grain yields, with an average increase of 31.88% compared with the yield in RTW0. Root systems at three soil layers (0–40 cm, 40–80 cm and below 80 cm) differentially contributed to grain yields with 78.32%, 12.09% and 9.59%, respectively. The growth peak of the deep root system in SSW1 was postponed to the filling stage, and the post-peak attenuation declining rates were also slowed. Therefore, SSW1 is an effective cultivation method improving grain yields and water use efficiency in lime concretion black soil.

The integration of the metasurface and antenna has brought new vitality to function integration and performance improvement for metasurfaces. In this study, we propose a radiation-scattering–integrated (RSI) design method of functional metasurfaces by incorporating antenna radiators into the substrates. The antenna radiators can also be considered as a band-stop frequency selective surface (FSS) embedded within the dielectric substrate, which adds up to the degree of freedom (DOF) in tailoring electromagnetic (EM) properties of the substrate. In this way, not only radiation function is added to the metasurfaces but also the original scattering-manipulation function is augmented. As an example, we apply this method to the design of a metasurface that can achieve a high radiation gain in-band and low-RCS out-of-band simultaneously. An antenna array was first designed, which uses circular patches as the radiators. Then, the antenna array was used as the substrate of a typical polarization conversion (PC) metasurface. The circular patch lies between the ground plane and the PC meta-atom, providing optimal electrical substrate thickness for PC at two separate bands. By adjusting structural parameters, the operating band of the antenna array can be made to lie in between the two PC bands. In this way, the metasurface can simultaneously possess high-gain radiation function in-band and high-efficiency PC function for RCS reduction out-of-band. A prototype was fabricated and measured. Both the simulated and measured results show that the metasurface can achieve satisfactory radiation gain in-band and significant RCS reduction out of band. This work provides an alternative method of designing multi-functional metasurfaces, which may find applications in smart skins and others.

In heavy oil development, flue-gas-assisted steam flooding can not only improve oil recovery but also reduce carbon emissions and realize the resource utilization of flue gas. In this paper, the variation in crude oil components produced by steam flooding and flue-gas-assisted steam flooding was studied by indoor displacement experiments and component determination, and the production properties of different components in flue gas, and the influence of flue gas proportion on residual oil components was explored. The results indicate that flue gas can enhance distillation and the production of light components in the steam flooding process. When the ratio of flue gas to steam ranges from 1 : 1 to 3 : 1, the larger the proportion of flue gas injection is, the larger the scope of steam thermal sweep is, the stronger the steam distillation effect is, and the greater the content of light components in residual oil and the change value of each component at the outlet and inlet are. Due to the difference in the dissolution of N2 and CO2 in heavy oil, at the early stage of displacement, the retention rate of CO2 in the formation in the early stage of displacement was higher, and the proportion of CO2 output was lower than the initial injection proportion. With the progress of displacement, the proportion of CO2 gradually increased, and the proportion of N2 gradually decreased. After gas channeling occurs, the N2 proportion increases and gradually approaches the injection proportion. The dissolution and precipitation of flue gas contribute to the formation of foam oil and improve the flow and production of crude oil. The research results are helpful to further understand the mechanism of flue-gas-assisted steam flooding and provide a theoretical basis for the improvement of this technology.

Rapid and precise air operation mission planning is a key technology in unmanned aerial vehicles (UAVs) autonomous combat in battles. In this paper, an end-to-end UAV intelligent mission planning method based on deep reinforcement learning (DRL) is proposed to solve the shortcomings of the traditional intelligent optimization algorithm, such as relying on simple, static, low-dimensional scenarios, and poor scalability. Specifically, the suppression of enemy air defense (SEAD) mission planning is described as a sequential decision-making problem and formalized as a Markov decision process (MDP). Then, the SEAD intelligent planning model based on the proximal policy optimization (PPO) algorithm is established and a general intelligent planning architecture is proposed. Furthermore, three policy training tricks, i.e., domain randomization, maximizing policy entropy, and underlying network parameter sharing, are introduced to improve the learning performance and generalizability of PPO. Experiments results show that the model in this work is efficient and stable, and can be adapted to the unknown continuous high-dimensional environment. It can be concluded that the UAV intelligent mission planning model based on DRL has powerful intelligent planning performance, and provides a new idea for researching UAV autonomy.

Abstract This paper investigates the CO2/N2 injection process in tight oil reservoirs considering the confinement effect. To study the microscopic physical mechanisms, the confinement effect is characterized by properties shift and capillarity and introduced into the flash calculation to obtain the phase equilibrium of mixture fluids (tight oil/CO2/N2) in tight porous media. The results indicate that the injected nitrogen gas could effectively maintain the reservoir pressure, while it also weakens the effects of the CO2 injection recovery mechanisms, notably diffusivity and viscosity reduction. In addition, a dual‐pore tight oil reservoir model is set up to investigate the CO2/N2 injection with ultra‐low permeability and hydraulic fracturing. The basic CO2 injection parameters are optimized by the orthogonal method. Based on CO2 injection process, three injection schemes of CO2/N2 injection, which are mixed‐gas injection, CO2‐alternating‐N2 (CAN) injection, and N2‐alternating‐CO2 (NAC) injection, were investigated and a comparative analysis was made for the pressure distribution, CO2 mole fraction distribution, and cumulative oil production. Based on this analysis, the CAN injection process proved to be the best injection scheme. A parametric analysis further suggested that the nitrogen gas injection rate was the most important factor. Besides, the effect of gravity drainage, reservoir permeability, nature fractures, and permeability heterogeneity on the oil production of CAN injection process were also investigated in detail. The results show that tight oil reservoir with better vertical connectivity, poor fracture growth, and higher heterogeneity is more favorable for the CO2/N2 injection process.

With accelerated urbanization and rapid expansion of the urban population, there is an increasing demand among urban residents for urban green spaces (UGS) and the ecosystem services (ES) they provide. The existing research mostly focuses on the spatial pattern of UGS types and ES provided by different UGS but ignores that residents’ preferences for UGS types and their ecological and social services should also be incorporated into the spatial planning decision-making of UGS. A web-based questionnaire was distributed randomly in urban areas of China and 1050 valid samples were collected in this study. Descriptive statistical analysis methods, structural equation modeling, and Pearson correlation were used to parse the residents’ preference for both UGS types, ecological–social services, and the relevant impact factors. The results showed that: (1) the strongest preference of residents for UGS and their ecological and social services are the attached green space, “beautifying the city”, and “physical and mental relaxation”, respectively; (2) the leading factors for residents’ access to UGS are “age” and “sufficient time”, except for attached green space. The most significant effect on both ecological and social services is the “season” factor. Further, “social gathering” and “exercise” are the services most and least likely to be affected. (3) Future planning of UGS should reinforce construction of attached green space and improve the aesthetics-related ES they provide. Construction of park green space and plaza green space should be enhanced to deal with the aging trend in society. Further, maintaining the existing construction of attached green space and building regional green space are crucial to the sustainability of UGS and its ecological–social services.

Urban green spaces (UGSs) are indispensable for providing various ecosystem services (ESs) to society and city-dwellers. The equitable allocation of ESs provided by UGSs is a prerequisite for maintaining urban sustainability and human well-being. However, empirical studies have assessed the dynamics of UGS equity from ES facets, while neglecting to strengthen integrated evaluation indicators and coupled spatially explicit models. A framework was developed in this study to assess the spatio-temporal patterns of ESs provided by UGSs and their equity based on models of the Intelligent Urban Ecosystem Management System, location entropy, and the Gini coefficient. The results indicated that with urban spatial expansion, in each concentric circle, the values of three ES averages were generally the lowest in the megacity (Xi’an), and the values of carbon sequestration and the recreation averages in the medium-sized cities (Baoji and Xianyang) were also lower than in the small-sized city (Tongchuan). The inequity of ESs provided by UGSs was exacerbated from 2000 to 2020 in the Xi’an Metropolitan Area. The ES equity was the worst in Xi’an and the best in Tongchuan. Areas with extremely low CR location entropy occupied 67.01% in 2020. As cities spatially expanded, areas with extremely low ES location entropy generally increased in 2020. Additionally, the zero-value area of the ES Gini coefficient in Xi’an was the largest from 2000 to 2020. The ES Gini values mostly increased in the same concentric circle of each city in 2020, which demonstrates that equity declined. Spatial equity could be improved by diversifying UGS structures, promoting spatial matching between the ES supply and beneficiaries’ demands, and integrating UGSs into any available space in future UGS planning. The findings of the study could offer insights for optimizing the equitable provision of UGS resources and the targeted planning of urban greening.

Summary: Most Li3VO4 anodes are obtained by pre-architecture methods in which Li3VO4 anode materials are prepared with more than six key processes including high-temperature annealing and long preparation time. Herein, we propose an in situ post-architecture strategy including Li3VO4-precursor solution (ink) preparation and then annealing at 250°C. The integrated Li3VO4 based electrode not only possesses good electrical conductivity and porous microstructure but also has superior stability because of Cu anchoring and inclusion by in situ catalysis. The integrated electrode demonstrates a high reversible capacity (865 mA h g−1 at 0.2 A g−1) and good cyclability (100% capacity retention after 200 cycles at 1 A g−1). More importantly, the post-architecture electrode has a high energy density of 773.8 Wh kg−1, much higher than reported Li3VO4-based materials, as well as most cathodes. Therefore, the electrode could be used to the printable cathode of low-voltage high-energy-density lithium batteries.

The overall survival of patients with lower grade glioma (LGG) varies greatly, but the current histopathological classification has limitations in predicting patients’ prognosis. Therefore, this study aims to find potential therapeutic target genes and establish a gene signature for predicting the prognosis of LGG. CD44 is a marker of tumor stem cells and has prognostic value in various tumors, but its role in LGG is unclear. By analyzing three glioma datasets from Gene Expression Omnibus (GEO) database, CD44 was upregulated in LGG. We screened 10 CD44-related genes via protein–protein interaction (PPI) network; function enrichment analysis demonstrated that these genes were associated with biological processes and signaling pathways of the tumor; survival analysis showed that four genes (CD44, HYAL2, SPP1, MMP2) were associated with the overall survival (OS) and disease-free survival (DFS)of LGG; a novel four-gene signature was constructed. The prediction model showed good predictive value over 2-, 5-, 8-, and 10-year survival probability in both the development and validation sets. The risk score effectively divided patients into high- and low- risk groups with a distinct outcome. Multivariate analysis confirmed that the risk score and status of IDH were independent prognostic predictors of LGG. Among three LGG subgroups based on the presence of molecular parameters, IDH-mutant gliomas have a favorable OS, especially if combined with 1p/19q codeletion, which further confirmed the distinct biological pattern between three LGG subgroups, and the gene signature is able to divide LGG patients with the same IDH status into high- and low- risk groups. The high-risk group possessed a higher expression of immune checkpoints and was related to the activation of immunosuppressive pathways. Finally, this study provided a convenient tool for predicting patient survival. In summary, the four prognostic genes may be therapeutic targets and prognostic predictors for LGG; this four-gene signature has good prognostic prediction ability and can effectively distinguish high- and low-risk patients. High-risk patients are associated with higher immune checkpoint expression and activation of the immunosuppressive pathway, providing help for screening immunotherapy-sensitive patients.

Cu(im)2-derived Cu@N-C composites were used for the first time as efficient heterogeneous catalysts for one-pot 1,3-dipolar cycloaddition of terminal alkynes, aryl halides, and sodium azide to preparation of 1,4-disubstituted 1,2,3-triazoles with broad substrate scope and high yields. The catalyst can be easily reused without the changes of structure and morphology, and the heterogeneity nature was confirmed from the catalyst recyclability and metal leaching test.

Summary: Metal-air batteries have high capacities and power densities, but performance is limited in the absence of oxygen. Hydrogen peroxide not only has oxygen storage capacity of ∼1,600 times that of air but is also in some ways more convenient for storage and transportation than high-pressure cylinders. H2O2 may be a viable alternative in non-oxygen conditions. Here, we report aqueous Zn-H2O2 battery that is designed by replacing O2 gas with hydrogen peroxide using Co/N doped carbon nanosheet as a multifunctional catalyst for oxygen reduction reaction, oxygen evolution reaction, and H2O2 decomposition. The optimized Zn-H2O2 battery exhibits superior high-rate discharging performance among 20–120 mA cm−2, 23% higher than that of Zn-air battery at the rate of 120 mA cm−2. As an application, two-serial Zn-H2O2 batteries can light a red LED array and work well in water. Therefore, we think Zn-H2O2 battery has numerous applications in high-power devices.

The focus of this paper is the effect of thickness stretching on the static and dynamic behaviors of functionally graded graphene reinforced composite (FG-GRC) plates. The bending and free vibration behaviors of FG-GRC plates under simply supported conditions are studied based on two plate theories, with or without taking into account the thickness stretching effect, respectively, and the effect of thickness stretching on FG-GRC plates is analyzed by comparing the calculated results of the two types of plate theories. The properties of composite materials are estimated by the modified Halpin-Tsai model and rule of mixture, Hamilton’s principle is used to construct its governing equation, and the Navier solution method is used to find the closed solution. The numerical results show that the effect of thickness stretching depends mainly on the transverse anisotropy of the FG-GRC plates, and the FG-GRC plates are most significantly affected by the thickness stretching when the graphene nanoplatelets (GPLs) are asymmetrically distributed, and the effect of thickness stretching tends to increase as the total number of layers and the weight fraction of GPLs increase.

Soil, as one of the three basic biophysical components, has been understudied using remote sensing techniques compared to vegetation and impervious surface areas (ISA). This study characterized land surfaces based on the brightness–darkness–greenness model. These three dimensions, brightness, darkness, and greenness, were represented by the first Tasseled Cap Transformation (TC1), Normalize Difference Snow Index (NDSI), and Normalized Difference Vegetation Index (NDVI), respectively. The Ratio Index for Bright Soil (RIBS) was developed based on TC1 and NDSI, and the Product Index for Dark Soil (PIDS) was established by TC1 and NDVI. Their applications to the Landsat 8 Operational Land Imager images and 500 m 8-day composite Moderate Resolution Imaging Spectroradiometer (MODIS) in China revealed the efficiency. The two soil indices proficiently highlighted soil covers with consistently the smallest values, due to larger TC1 and smaller NDSI values in bright soil, and smaller NDVI and TC1 values in dark soil. The RIBS is capable of distinguishing bright soil from ISA without masking vegetation and water body. The spectral separability bright soil and ISA were perfect, with a Jeffries–Matusita distance of 1.916. And the PIDS was the only soil index that could discriminate dark soil from other land covers including ISA. The soil areas in China were classified using a simple threshold method based on MODIS images. An overall accuracy of 94.00% was obtained, with the kappa index of 0.8789. This study provided valuable insights into developing indices for characterizing land surfaces from different perspectives.

Foam is widely used as a selective blocking agent through mobility control in oil field development. Its flow behavior in porous media has been investigated sufficiently, but few studies were carried out to understand the change of foam texture in flow. In this work, sandpack and micromodel experiments were conducted simultaneously to analyze foam flow behavior from the perspective of foam texture. Based on the measured flowing pressure and the observed foam image, the correlation between blocking pressure and foam texture was quantitatively investigated. The blocking pressure has a strong correlation with average diameter (-0.906) and variation coefficient (-0.78) and has a positive correlation with the filling ratio (0.84). These indicate that the blocking performance of foam is influenced by its texture closely. But path analysis shows only that the average diameter and variation coefficient have a significant direct effect on blocking pressure (-0.624 and -0.404). These show that the blocking capacity of foam is mainly influenced by the size and uniformity of bubbles. Tiny, dense, and homogeneous foam has a stronger blocking capacity. This study provides a deep insight of foam flow in porous media.

Climate change can have critical impacts on ecosystem services (ESs) and their inter-relationships, especially for water-related services. However, there has been little work done on characterizing the current and future changes in these services and their inter-relationships under a changing climate. Based on the revised universal soil loss equation (RUSLE), the soil conservation service curve number model (SCS-CN), and the improved stochastic weather-generator-based statistical downscaled global climate models (GCMs), we examined two important water-related services, namely, the soil conservation (SC) service and the flood mitigation (FM) service, and their inter-relationship under baseline and future climate scenarios (Representative Concentration Pathways (RCPs) 4.5 and 8.5). We took the Upper Hanjiang River Basin (UHRB), which is the core water source area of the China’s South-to-North Water Diversion Project (S–NWDP), as an illustration. The findings revealed that (1) the SC and FM services will both decrease under the two climate scenarios examined; (2) the SC and FM services showed a significant synergistic inter-relationship and the synergy will be improved by 16.48% and 2.95% under RCP 4.5 and RCP 8.5, respectively, which provides an opportunity for management optimization; (3) the ecological degradation in the UHRB will likely have serious consequences for the middle and lower reaches of the Hanjiang river basin, and therefore impact the actual economic benefits of the S–NWDP. This study points to the necessity for understanding the dynamic changes and inter-relationships of ecosystem services under future climate change and provides information regarding the consequences of climate change, which is useful for policy and infrastructure investment.

The metakaolin-based porous geopolymer were prepared by emulsion templating method with sunflower oil as the template agent. The effects of the type of emulsifiers with different ionic properties, including sodium stearate (SS), polyacrylamide (PAM), and cetyltrimethylammonium bromide (CTAB), which are respectively belonging to anionic, nonionic and cationic emulsifiers, on the paste viscosity, mechanical strength and pore structure of geopolymer were studied. Fourier transform infrared spectroscopy (FTIR) was used to characterize the influence of emulsion template on the geopolymerization. Scanning electron microscope (SEM) and Image-Pro Plus (IPP) software were used to examine the pore structure of geopolymers, including pore size distribution, average size and roundness of pores. Results indicate that geopolymerization is not significantly affected by the incorporation of emulsion template, while the average size, shape and connectivity of pores in geopolymer were significantly influenced by the type of emulsifiers. With the addition of SS, PAM, and CTAB, the average pore size were 18.1, 27.4, and 11.7 μ m, respectively, while the control is 18.9 μ m. Both the shape regularity and open porosity of pores were increased with SS and PAM, while no significant changes with CTAB. It is promising to make geopolymer with controllable macro pore structure by adjusting the types of emulsifiers in emulsion templating method by adjusting the oil-water interfacial tension and the particle dispersion.

In order to prepare self-supporting faujasite (FAU) zeolite, a self-supporting zeolite block was synthesized in situ by hydrothermal treatment of a metakaolin base geopolymer. The effects of hydrothermal conditions such as hydrothermal alkalinity, temperature and time on the phase composition, microstructure and mechanical strength of the hydrothermal samples were investigated and evidenced by a series of characterization methods such as X-ray diffraction (XRD), scanning electron microscopy (SEM), and Brunauer-Emmet-Teller (BET). The results showed that a self-supporting faujasite block could be obtained by hydrothermal treatment of the geopolymer block in 2 M NaOH solution at 90 °C for 24 h, which had high crystallinity, regular morphology and high compressive strength. The self-supporting zeolite block had a compressive strength of 11.7 MPa, a pore volume of 0.24 cm3/g, and an average pore diameter of 7.86 nm. The specific surface area and the microporous specific surface area of the self-supporting faujasite blocks were 80.36 m2/g and 19.7 m2/g, respectively.

Ongoing climate change and human activities have a great effect on vegetation dynamics. Understanding the impact of climate change and human activities on vegetation dynamics in different ecologically vulnerable regions has great significance in ecosystem management. In this study, the predicted NPP (Net Primary Productivity) and the actual NPP based on different ecological process data and models were combined to estimate the vegetation dynamics and their driving forces in the Northern Wind-sand, Loess Plateau, Arid Desert, Tibetan Plateau, and Karst regions from 2000 to 2015. The results indicated that the NPP in all ecologically vulnerable regions showed a restoration trend, except for that in the Karst region, and the percentage of areas in which NPP increased were, in order, 78% for the Loess Plateau, 71% for the Northern Wind-sand, 69% for the Arid Desert, 54% for the Tibetan Plateau, and 31% for the Karst regions. Vegetation restorations in the Northern Wind-sand and Arid Desert regions were primarily attributable to human activities (86% and 61% of the restoration area, respectively), indicating the success of ecological restoration programs. The Loess Plateau had the largest proportion of vegetation restoration area (44%), which was driven by combined effects of climate and human factors. In the Tibetan Plateau, the vegetation changes due to climate factors were primarily distributed in the west, while those due to human factors were primarily distributed in the east. Human activities caused nearly 60% of the vegetation degradation in the Karst region. Based on these results, it is recognizable that regional climate conditions are the key factor that limits ecological restoration. Therefore, future policy-making should pay more attention to the local characteristics of different ecological vulnerable regions in regional ecosystem management to select reasonable restoration measures, improve restoration efficiency, and maximize the benefits of ecological restoration programs.

Foamy oil is considered an important reason for the anomalous performance in depletion development for some heavy oil reservoirs, but its influence factors remain to be fully investigated. In order to determine the effect of oil viscosity and asphaltene on foamy oil, ten oil samples including two types (deasphalted oil and asphaltenic oil) and five viscosities were used in the work. On this basis, depletion experiments were conducted in a sandpack and microscopic visualization model. Then, viscoelastic moduli of the oil⁻gas interface were measured to analyze the mechanisms of viscosity and asphaltene of foamy oil from the perspective of interfacial viscoelasticity. Results show that, with the decrease of the oil viscosity, the foamy oil performance in depletion development worsened, including a rapider decline in average pressure, earlier appearance of gas channeling, shorter period of foamy oil, and lower contribution of foamy oil to recovery. Asphaltene had an influence on foamy oil only in the viscosity range between 870 mPa∙s and 2270 mPa∙s for this study. The effect of viscosity and asphaltene on foamy oil can be explained by the viscoelasticity of bubble film. With the increase of oil viscosity, the interfacial viscous modulus increases significantly, indicating the bubble film becomes stronger and more rigid. Asphaltene, like armor on the bubble film, can improve the viscoelastic modulus, especially at lower viscosity. This can inhibit the coalescence of micro-bubbles and increase the possibility of splitting. This work identifies the effects of oil viscosity and asphaltene on foamy oil systematically and provides theoretical support for foamy oil production.

An objective and effective method to distinguish the influence of climate change and human activities on vegetation dynamics has great significance in the design and implementation of ecosystem restoration projects. Based on the Moderate Resolution Imaging Spectroradiometer (MODIS) remote data and the Miami and Carnegie–Ames–Stanford Approach (CASA) model, this study simulated and used net primary productivity (NPP) as an indicator to identify vegetation dynamics and their driving forces in the Jinghe River basin from 2000 to 2014. The results showed that: (1) The vegetation in the Jinghe River basin, which accounted for 84.4% of the study area, showed an increasing trend in NPP; (2) Human activities contributed most to vegetation restoration, which accounted for 54.5% of the areas; 24.0% of the areas showed an increasing trend in the NPP that was dominated by climate factors. Degradation dominated by human activities accounted for 4.3% of the study area, and degradation dominated by climate factors resulted in 17.2%; (3) The rate of vegetation degradation in areas dominated by climate factors rose with increased slope, where the arid climate caused shortages of water resources, and the human-dominated vegetation restoration activities exacerbated the vegetation’s water demand further, which surpassed the carrying capacity of regional water resources and led ultimately to vegetation degradation. We recommend that future ecological restoration programs pay more attention to maintaining the balance between ecosystem restoration and water resource demand to maximize the benefits of human activities and ensure the vegetation restoration is ecologically sustainable.

During aircraft braking, brake-induced frequent wheel slippage may cause coupling vibration between the antiskid brake system and landing gear. Brake-induced longitudinal coupled vibration is also known as "gear walk" vibration. Gear walk vibration not only reduces the structural life of the landing gear but also impairs the efficiency of the aircraft braking system. This paper focuses on the landing gear walk vibration mechanism and suppresses the method by modifying the antiskid brake control law. Firstly, a comprehensive multiwheel landing gear walk vibration model is developed. This model describes not only the longitudinal and vertically coupled vibration characteristics of the landing gear but also the dynamics of the aircraft braking system and the fuselage. Secondly, by simplifying the landing gear walk to the transverse vibration of a cantilever beam with a tip mass, the landing gear walk vibration mechanism is revealed in the frequency domain. Finally, a method to suppress landing gear walk vibration by modifying the pressure-bias-modulated (PBM) antiskid braking control law is proposed, which can solve the serious landing gear walk vibration problem caused by the conventional PBM control law. Simulation and experimental results show that the proposed method can suppress the landing gear walk vibration while improving braking efficiency. [ABSTRACT FROM AUTHOR]

Rapid global urbanization has perturbed ecosystem structures and functions, resulting in ecological risk and threatening sustainable human well-being and socioeconomic development. However, scientific indicators to analyze ecosystem service (ES) risk patterns need to be explored in detail. In addition, studies on ES supply risk are stagnating on historical or status explorations, especially from the view of disturbance from land-use changes. This study seeks to develop a framework for modeling past-future ES supply risk pattern evaluation and probing into ES risk patterns under different future land-use scenarios. To achieve this objective, the framework integrates the Future Land Use Simulation (FLUS) model, the Intelligent Urban Ecosystem Management System (IUEMS) model, and an established indicator system incorporating ES supply trend, hotspots and coldspots, and ES trade-offs, and synergies. The results show that: (1) In 2050, the supply of climate regulation in the Xi'an Metropolitan Area (XMA) will increase, while that of carbon sequestration and recreation will decrease. In 2050, the supply of climate regulation is the highest under ecological protection (EP) scenario, while the supply of carbon sequestration and recreation are the highest under cropland protection (CP) scenario. (2) From 2000 to 2050, the hotspots and coldspots of climate regulation increase in both natural development (ND) scenario and CP scenario. Notably, CP scenario experiences the most significant reduction in extremely significant hotspots and coldspots of carbon sequestration. From 2000 to 2050, at the regional and pixel scales, climate regulation and carbon sequestration mainly show trade-offs, and carbon sequestration and recreation show synergies. (3) ES supply risk in XMA is high in the center and low in the north and south. The ES supply risk from 2000 to 2050 is increasing, with expanding "extremely high risk", "high risk", and "extremely safe" areas. ES supply risk management should adhere to more strict land-use policies and guidelines, management zoning for areas with different levels of ES risk, and an accurate understanding of ES trade-offs and synergies for scientific risk management. This study could provide theoretical and technical references for ES risk assessment research and promote scientific ecological risk management. [ABSTRACT FROM AUTHOR]