Search Results (31)

The current widespread use of plastics is a significant source of environmental pollution and increases the carbon load in the atmosphere, which has precipitated an urgent drive to replace plastics with biomass-based materials. In this paper, we prepared a lignocellulose-based, high-strength, water-resistant composite based on eucalyptus waste sawdust combined with a polyurethane prepolymer. The preparation process included pretreating sawdust with deep eutectic solvents (DESs) to remove some of the lignin and hemicellulose. A prepolymer preparation involving isocyanate groups using the prepolymerization of polyethylene glycol (PEG) with hexamethylene diisocyanate (HDI) grafted the prepolymers to the hydroxyl of the pretreated wood fibers, which were subsequently blended with acetylated pretreated sawdust to create the composite. The composite contained 67% wood fibers, possessed good tensile strength, and exhibited Young’s moduli of 18 MPa and 484 MPa. It was water-resistant with a contact angle of 92° and had a low water absorption of 32%, and it maintained a wet tensile strength of 5.71 MPa. The composite offers several advantages, including UV protection and thermal stability. This high-performance wood waste composite provides an alternative green production option for producing plastic materials. Full article

Plastic waste has been gradually accumulating in the environment due to rapid population growth and increasing consumer demand, posing threats to both the environment and human health. In this overview, we provide a comprehensive understanding of the degradation of plastics in real environments, such as soil, aquatic environment, landfill, and compost. Both conventional and biodegradable plastics exhibit limited degradation in real environments, except for biodegradable plastics during industrial composting with high thermophilic temperatures. Meanwhile, we also review techniques for enhanced degradation of plastics such as physical technologies (e.g., photocatalysis, mechanical degradation, and pyrolysis), chemical technologies (e.g., hydrolysis, alcoholysis, ammonia, strong oxidation, and supercritical fluids), and biotechnologies (e.g., microorganisms, microfauna, and microalgae). The future research directions for the enhancement of plastic degradation are also discussed, such as the establishment of equivalency standards, adoption of internal control techniques, the control of precise recycling of plastic products, and the ecotoxicology of their degradation products. Therefore, this review comprehensively summarizes the state of plastic degradation in real environments and proposes methods to improve plastic degradation, providing a theoretical basis for the future control and disposal of plastics. Full article

The Leaf Area Index (LAI) is a crucial structural parameter linked to the photosynthetic capacity and biomass of crops. While integrating machine learning algorithms with spectral variables has improved LAI estimation over large areas, excessive input parameters can lead to data redundancy and reduced generalizability across different crop species. To address these challenges, we propose a novel framework based on Bayesian-Optimized Random Forest Regression (Bayes-RFR) for enhanced LAI estimation. This framework employs a tree model-based feature selection method to identify critical features, reducing redundancy and improving model interpretability. A Gaussian process serves as a prior model to optimize the hyperparameters of the Random Forest Regression. The field experiments conducted over two years on maize and wheat involved collecting LAI, hyperspectral, multispectral, and RGB data. The results indicate that the tree model-based feature selection outperformed the traditional correlation analysis and Recursive Feature Elimination (RFE). The Bayes-RFR model demonstrated a superior validation accuracy compared to the standard Random Forest Regression and Pso-optimized models, with the R² values increasing by 27% for the maize hyperspectral data, 12% for the maize multispectral data, and 47% for the wheat hyperspectral data. These findings suggest that the proposed Bayes-RFR framework significantly enhances the stability and predictive capability of LAI estimation across various crop types, offering valuable insights for precision agriculture and crop monitoring. Full article

In this study, we introduce a novel method for an online trajectory replanning approach for fixed-wing Unmanned Aerial Vehicles (UAVs). Our method integrates moving obstacle predictions within a gradient-based optimization framework. The trajectory is represented by uniformly discretized waypoints, which serve as the optimization variables within the cost function. This cost function incorporates multiple objectives, including obstacle avoidance, kinematic and dynamic feasibility, similarity to the reference trajectory, and trajectory smoothness. To enhance prediction accuracy, we combine physics-based and pattern-based methods for predicting obstacle movements. These predicted movements are then integrated into the online trajectory replanning framework, significantly enhancing the system’s safety. Our approach provides a robust solution for navigating dynamic environments, ensuring both optimal and secure UAV operation. Full article

Cadmium (Cd) contamination in agricultural soils has emerged as a significant concern, particularly due to its potential impact on plant-based food. Soil pH reductions can exacerbate Cd mobility, leading to excessive accumulation in crops. While liming has been demonstrated as an effective method to mitigate Cd accumulation in rice grains in acid soils of southern China, its efficacy in remediating acid soils in northern China remains unclear. In this study, a multi-year field experiment was conducted on farmland impacted by zinc ore smelting at coordinates of 33.92° N 112.46° E to investigate the use of limestone for controlling Cd accumulation in wheat and maize grains. The results indicated that applying 7.5 t ha⁻¹ of limestone significantly raised the soil pH from 4.5 to 6.8 as anticipated. Different rates of limestone application (2.25, 4.45, and 7.50 t ha⁻¹) reduced Cd bioavailability in the soil by 20–54%, and Cd accumulation in wheat grains by 5–38% and maize grains by 21–63%, without yield penalty. The remediation effects were sustained for at least 27 months, highlighting limestone as a promising ameliorant for smelting-affected farmland in northern China. Full article

Liquid hydrogen storage is an important way of hydrogen storage and transportation, which greatly improves the storage and transportation efficiency due to the high energy density but at the same time brings new safety hazards. In this study, the liquid hydrogen leakage in the storage area of a hydrogen production station is numerically simulated. The effects of ambient wind direction, wind speed, leakage mass flow rate, and the mass fraction of gas phase at the leakage port on the diffusion behavior of the liquid hydrogen leakage were investigated. The results show that the ambient wind direction directly determines the direction of liquid hydrogen leakage diffusion. The wind speed significantly affects the diffusion distance. When the wind speed is 6 m/s, the diffusion distance of the flammable hydrogen cloud reaches 40.08 m, which is 2.63 times that under windless conditions. The liquid hydrogen leakage mass flow rate and the mass fraction of the gas phase have a greater effect on the volume of the flammable hydrogen cloud. As the leakage mass flow rate increased from 5.15 kg/s to 10 kg/s, the flammable hydrogen cloud volume increased from 5734.31 m³ to 10,305.5 m³. The installation of a barrier wall in front of the leakage port can limit the horizontal diffusion of the flammable hydrogen cloud, elevate the diffusion height, and effectively reduce the volume of the flammable hydrogen cloud. This study can provide theoretical support for the construction and operation of hydrogen production stations. Full article

With the rapid development of hydrogen energy worldwide, the number of hydrogen energy facilities, such as hydrogen refueling stations, has grown rapidly in recent years. However, hydrogen is prone to leakage accidents during use, which could lead to hazards such as fires and explosions. Therefore, research on the safety of hydrogen energy facilities is crucial. In this paper, a study of high-pressure hydrogen jet flame accidents is conducted for a proposed integrated hydrogen production and refueling station in China. The effects of leakage direction and leakage port diameter on the jet flame characteristics are analyzed, and a risk assessment of the flame accident is conducted. The results showed that the death range perpendicular to the flame direction increased from 2.23 m to 5.5 m when the diameter of the leakage port increased from 4 mm to 10 mm. When the diameter of the leakage port is larger than 8 mm, the equipment on the scene will be within the boundaries of the damage. The consequences of fire can be effectively mitigated by a reasonable firewall setup to ensure the overall safety of the integrated station. Full article

Ti-Cr-V-based alloys have been utilized across various domains, including aerospace structural and functional materials and hydrogen storage materials. Investigating the phase relations in the Ti-Cr-V system is significant in supporting the material design for these applications. In the present work, the isothermal sections at 1000, 1100, and 1200 °C for the Ti-Cr-V system were precisely determined through a systematic investigation using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD). The phase region of Cr₂Ti was entirely elucidated for the first time. As the temperature decreased from 1200 to 1000 °C, the V solubility range of Cr₂Ti increased from 5.3 wt.% to 10.0 wt.%, while the Ti solubility range essentially remained constant at approximately 31.0–33.9 wt.%. In addition, it was suggested that the stable structure of Cr₂Ti was C36 at 1200 °C and C15 at 1000 and 1100 °C. The present work will support thermodynamic re-assessment research. Full article

Photoinduced metal-free ATRP has been successfully applied to fabricate thermo-responsive cellulose graft copolymer (PNIPAM-g-Cell) using 2-bromoisobuturyl bromide-modified cellulose as the macroinitiator. The polymerization of N-isopropylacrylamide (NIPAM) from cellulose was efficiently activated and deactivated with UV irradiation in the presence of an organic-based photo-redox catalyst. Both FTIR and ¹³C NMR analysis confirmed the structural similarity between the obtained PNIPAM-g-Cell and that synthesized via traditional ATRP methods. When the concentration of the PNIPAM-g-Cell is over 5% in water, it forms an injectable thermos-responsive hydrogel composed of micelles at 37 °C. Since organic photocatalysis is a metal-free ATRP, it overcomes the challenge of transition-metal catalysts remaining in polymer products, making this cellulose-based graft copolymer suitable for biomedical applications. In vitro release studies demonstrated that the hydrogel can continuously release DOX for up to 10 days, and its cytotoxicity indicates that it is highly biocompatible. Based on these findings, this cellulose-based injectable, thermo-responsive drug-loaded hydrogel is suitable for intelligent drug delivery systems. Full article

Laser Time Transfer (LTT) has proven to be able to improve remote time transfer accuracy compared to microwave technology. The impact of satellite clock errors and atmospheric delays during LTT will be further reduced in the common-view mode. The challenge is presented as an optimization problem that is limited by satellite trajectories. This paper introduces an improved simulated annealing algorithm designed to maximize the common-view possibility among various station pairs within regional Satellite Laser Ranging (SLR) networks by optimizing satellite orbit trajectories. The study proposes a system model that integrates LTT principles with satellite visibility considerations. The simulated annealing algorithm is improved with new annealing strategies that incorporate control strategies, and modify the cooling function. Comparative simulation analyses demonstrate the effectiveness of the algorithm, resulting in a significant reduction in computation time by over 10 times. The optimized orbits exhibit common-view windows between 3.337 and 8.955 times longer than existing orbits. Further simulations are conducted to optimize the orbits, and common-view models are established for 45 pairs among 10 stations. The optimizations result in common-view times ranging from 6.183 to 60.633 min in the Asia-Pacific region and from 5.583 to 61.75 min in the Europe-to-Asia region. This can provide valuable references for designing satellite constellations. Full article

In industrial production, the quality, reliability, and precision of parts determine the overall quality and performance of various mechanical equipment. However, existing part defect detection methods have shortcomings in terms of feature extraction and fusion, leading to issues of missed detection. To address this challenge, this manuscript proposes a defect detection algorithm for parts (CRD-YOLO) based on the improved YOLOv5. Our first aim is to increase the regional features of small targets and improve detection accuracy. In this manuscript, we design the channel- aware aggregation (CAA) module, utilizing a multi-branch convolutional segmentation structure and incorporating an attention mechanism and ConvNeXt V2 Block as bottleneck layers for feature processing. Secondly, the re-parameterization asymptotic module (RAFPN) is used to replace the original model neck structure in order to improve the interaction between shallow-detail features and deeper semantic features, and to avoid the large semantic gaps between non-neighboring layers. Then, the DO-DConv module is encapsulated within the BN layer and the LeakyReLU activation function to become the DBL module, which further processes the feature output from the backbone network and fuses neck features more comprehensively. Finally, experiments with the self-made dataset show that the model proposed in this paper improves the accuracy of detecting various types of defect. In particular, it increased the accuracy of detecting bearing scuffing defects with significant dimensional variations, with an improvement of 6%, and gear missing teeth defects with large shape differences, with an 8.3% enhancement. Additionally, the mean average precision (mAP) reached 96.7%, an increase of 5.5% and 6.4% compared to YOLOv5s and YOLOv8s, respectively. Full article

Pancreatic ductal adenocarcinoma (PDAC) is associated with enhanced aerobic glycolysis through elevated glucose uptake and the upregulated expression of genes encoding rate-limiting glycolytic enzymes. However, the direct impact of altered glycolytic pathways on pancreatic tumor progression has not been thoroughly investigated. Here, we utilized two strains of BAC transgenic mice with pancreatic expression of two distinct sets of glycolytic genes each arranged in a polycistronic fashion (PFKFB3-HK2-GLUT1 and LDHA-PDK1, respectively) to investigate the role of altered glycolysis on the development of pancreatic ductal tumor development in the Pdx1-Cre; LSL-Kras^G12D mice. The overexpression of the two sets of glycolytic genes exhibited no significant effects on tumor development in the 4–5-month-old mice (the PanIN2 lesions stage). In the 9–10-month-old mice, the overexpression of PFKFB3-HK2-GLUT1 significantly accelerated PanIN3 progression, exhibiting elevated levels of ductal cell marker CK19 and tumor fibrosis. Surprisingly, the overexpression of LDHA-PDK1 significantly attenuated the progression of PanIN3 in the 9–10-month-old mice with significantly downregulated levels of CK19 and fibrosis. Therefore, distinct set of glycolytic enzymes that are involved in different glycolytic routes exhibited contrasting effects on pancreatic ductal tumor development depending on the tumor stages, providing novel insights into the complexity of the glycolytic pathway in the perspective of PDAC development and therapy. Full article

An imbalance in PI3K/AKT/mTOR pathway signaling in humans often leads to cancer. Therefore, the investigation of anti-cancer medications that inhibit PI3K and mTOR has emerged as a significant area of research. The aim of this study was to explore the effect of XIN-10, a dual PI3K/mTOR inhibitor, on the growth as well as antiproliferation of tumor cells and to investigate the anti-tumor mechanism of XIN-10 by further exploration. We screened three cell lines for more in-depth exploration by MTT experiments. From the AO staining, cell cycle and apoptosis, we found that XIN-10 had a more obvious inhibitory effect on the MCF-7 breast cancer cell line and used this as a selection for more in-depth experiments. A series of in vitro and in vivo experiments showed that XIN-10 has superior antiproliferative activity compared with the positive drug GDC-0941. Meanwhile, through the results of protein blotting and PCR experiments, we concluded that XIN-10 can block the activation of the downstream pathway of mTOR by inhibiting the phosphorylation of AKT(S473) as well as having significant inhibitory effects on the gene exons of PI3K and mTOR. These results indicate that XIN-10 is a highly potent inhibitor with low toxicity and has a strong potential to be developed as a novel PI3Kα/mTOR dual inhibitor candidate for the treatment of positive breast cancer. Full article

Objective: To assess the effectiveness of multi-model strategies on healthcare-associated infections (HAIs) caused by multi-drug resistant organisms (MDROs) in rehabilitation units. Methods: A semi-experimental study was conducted in a rehabilitation unit with 181 beds from January 2021 to December 2022 in a teaching hospital with 4300 beds in China. In 2021, many basic prevention and control measures were conducted routinely. Based on the basic measures, strengthening multi-model strategies for the prevention and control of MDROs was pursued year-round since 1 January 2022. Results: A total of 6206 patients were enrolled during the study period. The incidence density of HAIs caused by MDROs decreased from 1.22 (95% CI, 0.96~1.54) cases/1000 patient-days in the pre-intervention period to 0.70 (95% CI, 0.50~0.95) cases/1000 patient-days (p = 0.004). Similarly, the incidence of HAIs in the intervention period was 50.85% lower than that in the pre-intervention period (2.02 (95% CI, 1.50~2.72) vs. 4.11 (95% CI, 3.45–4.85) cases/100 patients, p < 0.001). The rate of MDROs isolated from the environment decreased by 30.00%, although the difference was not statistically significant (p = 0.259). Conclusion: Multi-model strategies can reduce the incidence of HAIs and HAIs caused by certain MDROs in the rehabilitation unit. Full article

Background: Attention deficit hyperactivity disorder (ADHD) affects approximately 2–7% of children worldwide and has become a global public health concern. The health effects of green space on ADHD in young children are unclear. We investigated associations between school-surrounding greenness and hyperactivity behaviors in preschool children. Methods: We performed a cross-sectional analysis using data of 66,678 preschool children (mean age: 3.53 years) from an on-going cohort in Shenzhen, China. The greenness surrounding kindergartens was measured using satellite-derived Normalized Difference Vegetation Index (NDVI) values at buffers of 250 m, 500 m, and 1000 m. Children’s hyperactivity behaviors were measured using the validated Conners’ Parent Rating Scale-Revised. We used generalized linear mixed models to assess the associations of greenness exposure with hyperactivity behaviors with adjustment for a variety of covariates. Results: Exposure to higher school-surrounding greenness was associated with lower prevalence of hyperactivity behaviors. In fully adjusted models, the odds ratio of hyperactivity behaviors in relation to an IQR (0.1) increase in NDVI at the 250 m buffer was 0.91 [confidence interval (CI): 0.84,0.98]. Consistent results were observed for greenness at the 500 m and 1000 m buffers. The negative association between greenness and hyperactivity behaviors was more pronounced in boys than in girls. Conclusions: Our findings suggest that higher levels of school-surrounding green spaces are associated with a lower risk of hyperactivity behaviors in preschool children. Full article