Beijing, China’s capital city, has experienced decades of severe land subsidence due to the long-term overexploitation of groundwater. The implementation of the South-to-North Water Diversion Project ...(SNWDP) and artificial ecological restoration have significantly changed Beijing’s hydro-ecological and geological environment in recent years, leading to a widespread rise in groundwater levels. However, whether the related land subsidence has slowed down or reversed under these measures has not yet been effectively monitored and quantitatively analyzed in terms of time and space. Accordingly, in this study, we proposed using an improved time-series deformation method, which combines persistent scatterers and distributed scatterers, to process Sentinel-1 images from 2015 to 2022 in the Beijing Plain region. We performed a geospatial analysis to gain a better understanding of how the new hydrological conditions changed the pattern of deformation on the Beijing Plain. The results indicated that our combined PS and DS method provided more measurements both in total quantity and spatial density than conventional PSI methods. The land subsidence in the Beijing Plain area has been effectively alleviated from a subsidence region of approximately 1377 km2 in 2015 to only approximately 78 km2 in 2022. Ecological restoration areas in the northeastern part of the Plain have even rebounded over this period, at a maximum of approximately 40 mm in 2022. The overall pattern of ground deformation (subsidence and uplift) is negatively correlated with changes in the groundwater table (decline and rise). Local deformation is controlled by the thickness of the compressible layer and an active fault. The year 2015, when anthropogenic water transfers were eliminated and ecological measures to recharge groundwater were implemented, was the crucial turning point of the change in the deformation trend in the subsidence history of Beijing. Our findings carry significance, not only for China, but also for other areas where large-scale groundwater extractions are causing severe ground subsidence or rebound.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Pig epiblast-derived pluripotent stem cells are considered to have great potential and broad prospects for human therapeutic model development and livestock breeding. Despite ongoing attempts since ...the 1990s, no stably defined pig epiblast-derived stem cell line has been established. Here, guided by insights from a large-scale single-cell transcriptome analysis of pig embryos from embryonic day (E) 0 to E14, specifically, the tracing of pluripotency changes during epiblast development, we developed an in vitro culture medium for establishing and maintaining stable pluripotent stem cell lines from pig E10 pregastrulation epiblasts (pgEpiSCs). Enabled by chemical inhibition of WNT-related signaling in combination with growth factors in the FGF/ERK, JAK/STAT3, and Activin/Nodal pathways, pgEpiSCs maintain their pluripotency transcriptome features, similar to those of E10 epiblast cells, and normal karyotypes after more than 240 passages and have the potential to differentiate into three germ layers. Strikingly, ultradeep in situ Hi-C analysis revealed functional impacts of chromatin 3D-spatial associations on the transcriptional regulation of pluripotency marker genes in pgEpiSCs. In practice, we confirmed that pgEpiSCs readily tolerate at least three rounds of successive gene editing and generated cloned gene-edited live piglets. Our findings deliver on the long-anticipated promise of pig pluripotent stem cells and open new avenues for biological research, animal husbandry, and regenerative biomedicine.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
•Influence of mixing time on chemical and physical environment of paste was assessed.•Mixing time has significant effect on the property of paste.•Mixing action greatly accelerates the hydration ...kinetics in the acceleration period.•Excessive mixing reduces the UCS in 28 days of curing.
Mixing is a crucial step in the application of any cement-based material. To have a clear understanding of the effect of mixing on cemented paste backfill (CPB) properties is necessary for the preparation of high-quality CPB. This paper researches the effect of mixing time on fresh and hardened properties of CPB, such as hydration kinetics, mechanical property, micro-structural characterization, and ion elution by using inductively coupled plasma mass spectrometry (ICP). The results show that the hydration kinetics and mechanical property of the CPB are sensitive to the mixing time. The mixing time mainly affects the acceleration period, and an improved shearing condition is beneficial to the improvement of the mechanical strength of CPB, especially the early strength, while excessive mixing causes deterioration to mechanical property. These observations can be explained by changes in physical and chemical composition of fresh state CPB due to different mixing programs.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In recent years, against the backdrop of the national high attention to cybersecurity, the implementation of grade protection systems has been vigorously carried out in various industries within the ...Internet+ environment. However, the construction of grade protection systems has gradually revealed several issues: network product providers have a weak security awareness and lack of secure development experiences, leading to systems often failing to meet their grade protection requirements; Grade protection evaluation is complex and tedious, consuming a significant amount of time and labor costs. To address the issues above, this paper proposes a construction method for grade protection systems based on STRIDE threat modeling: by establishing the correspondence between threats and grade protection requirements, threats are eliminated during the system development process while implementing the content of grade protection requirements; through the security verification of threat elimination, materials for grade protection evaluation are accumulated, and work reuse is leveraged to alleviate the workload of grade protection evaluation. Implementing this method can effectively promote the construction of grade protection systems.
The repair of bone defects is ideally accomplished with bone tissue engineering. Recent studies have explored the possibility of functional modification of scaffolds in bone tissue engineering. We ...prepared an SF-CS-nHA (SCN) biomimetic bone scaffold and functionally modified the scaffold material by adding a polydopamine (PDA) coating loaded with exosomes (Exos) of marrow mesenchymal stem cells (BMSCs). The effects of the functional composite scaffold (SCN/PDA-Exo) on BMSC proliferation and osteogenic differentiation were investigated. Furthermore, the SCN/PDA-Exo scaffolds were implanted into animals to evaluate their effect on bone regeneration.
SCN biomimetic scaffolds were prepared by a vacuum freeze-drying/chemical crosslinking method. A PDA-functionalized coating loaded with BMSC-Exos was added by the surface coating method. The physical and chemical properties of the functional composite scaffolds were detected by scanning electron microscopy (SEM), energy spectrum analysis and contact angle tests. In vitro, BMSCs were inoculated on different scaffolds, and the Exo internalization by BMSCs was detected by confocal microscopy. The BMSC proliferation activity and cell morphology were detected by SEM, CCK-8 assays and phalloidin staining. BMSC osteogenic differentiation was detected by immunofluorescence, alizarin red staining and qRT‒PCR. In vivo, the functional composite scaffold was implanted into a rabbit critical radial defect model. Bone repair was detected by 3D-CT scanning. HE staining, Masson staining, and immunohistochemistry were used to evaluate bone regeneration.
Compared with the SCN scaffold, the SCN/PDA-Exo-functionalized composite scaffold had a larger average surface roughness and stronger hydrophilicity. In vitro, the Exos immobilized on the SCN/PDA-Exo scaffolds were internalized by BMSCs. The BMSC morphology, proliferation ability and osteogenic differentiation effect in the SCN/PDA-Exo group were significantly better than those in the other control groups (p < 0.05). The effects of the SCN/PDA-Exo functional composite scaffold on bone defect repair and new bone formation were significantly better than those of the other control groups (p < 0.05).
In this study, we found that the SCN/PDA-Exo-functionalized composite scaffold promoted BMSC proliferation and osteogenic differentiation in vitro and improved bone regeneration efficiency in vivo. Therefore, combining Exos with biomimetic bone scaffolds by functional PDA coatings may be an effective strategy for functionally modifying biological scaffolds.
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•Combined BMSC-Exos with biomimetic bone scaffolds by functional polydopamine coatings.•SCN/PDA-Exo-functionalized scaffold promoted BMSC proliferation and osteogenic differentiation.•SCN/PDA-Exo-functionalized scaffold improves the efficiency of bone regeneration.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Abstract Perovskite/silicon tandem solar cells hold great promise for realizing high power conversion efficiency at low cost. However, achieving scalable fabrication of wide-bandgap perovskite (~1.68 ...eV) in air, without the protective environment of an inert atmosphere, remains challenging due to moisture-induced degradation of perovskite films. Herein, this study reveals that the extent of moisture interference is significantly influenced by the properties of solvent. We further demonstrate that n-Butanol (nBA), with its low polarity and moderate volatilization rate, not only mitigates the detrimental effects of moisture in air during scalable fabrication but also enhances the uniformity of perovskite films. This approach enables us to achieve an impressive efficiency of 29.4% (certified 28.7%) for double-sided textured perovskite/silicon tandem cells featuring large-size pyramids (2–3 μm) and 26.3% over an aperture area of 16 cm 2 . This advance provides a route for large-scale production of perovskite/silicon tandem solar cells, marking a significant stride toward their commercial viability.
As one of the most abundant stromal cells, fibroblasts are primarily responsible for the production and remodeling of the extracellular matrix. Traditionally, fibroblasts have been viewed as ...quiescent cells. However, recent advances in multi-omics technologies have demonstrated that fibroblasts exhibit remarkable functional diversity at the single-cell level. Additionally, fibroblasts are heterogeneous in their origins, tissue locations, and transitions with stromal cells. The dynamic nature of fibroblasts is further underscored by the fact that disease stages can impact their heterogeneity and behavior, particularly in immune-mediated inflammatory diseases such as psoriasis, inflammatory bowel diseases, and rheumatoid arthritis, etc. Fibroblasts can actively contribute to the disease initiation, progression, and relapse by responding to local microenvironmental signals, secreting downstream inflammatory factors, and interacting with immune cells during the pathological process. Here we focus on the development, plasticity, and heterogeneity of fibroblasts in inflammation, emphasizing the need for a developmental and dynamic perspective on fibroblasts.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In order to reveal the behaviors of crack initiation and short fatigue crack propagation in laser cladding IN718 under high temperature conditions, very high cycle fretting fatigue (VHCFF) ...experiments were conducted at 650 ℃ with a transverse clamping force of P=400N and different axial stress loading conditions to obtain S_N data. The surface wear morphology and fracture morphology characteristics were analyzed by scanning electron microscope (SEM) and white light interferometer. Additionally, the microstructure characteristics of grains in the short fatigue crack region were examined through electron back scatter diffraction (EBSD). Parameters such as equivalent grain size, grain elastic modulus, Schmid factor, geometric compatibility factor, twist angle, and tilt angle were considered in the analysis of the characteristics of fatigue crack initiation and propagation. The results indicate that fretting fatigue cracks tend to initiate on grains with higher Schmid factors, larger equivalent grain size, and lower grain elastic modulus on the fretting contact surface. Moreover, the short fatigue cracks tend to propagate along the grains with the microstructural features of the high Schmid factor, the geometric compatibility factor of m′>0.4, the twist angle of α<50°, and the tilt angle of β<50°.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•Monte Carlo simulation (MCS) solves the sparsity problem for small samples of VHCF.•The proposed dynamic recursive network validates the effectiveness of MCS for enhancing small sample ...dataset.•Achieving accurate prediction of VHCF for small sample cases and reducing the cost and time.
Few machine learning (ML) methods have been applied to the prediction of the highly dispersed and low Very High Cycle Fatigue (VHCF) specimens. The present work attempts to use Monte Carlo Simulation (MCS) to expand the low VHCF dataset and thereby improve the predictive performance of ML models. Moreover, a dynamic recurrent ML model is proposed to be used with the extended dataset. VHCF experiments conducted under three different stress ratios (R = −1, 0.05 and 0.5) and two temperatures (26 °C and 500 °C) show that the use of MCS has significantly improved the predictive capabilities of the ML model, with predictions almost within the scattered band of 4.0 and closer to 2.0, thus solving the challenge of predicting the life of sparse VHCF specimens made of Ti60 alloy, the cost and time of VHCF prediction will be greatly reduced.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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