Search Results (38)

Nitrous oxide (N₂O) is a potent greenhouse gas with intensive emissions from acidic soil. This study explored the impact of the disruption of the microbial balance from microbial inhibitors (streptomycin and cycloheximide) on soil’s N₂O emission and nitrogen (N) dynamics. Under all the conditions examined, biotic processes accounted for 96–98% of total N₂O emissions. High concentrations of streptomycin (6 and 10 mg g⁻¹) reduced N₂O emissions from 2.24 μg kg⁻¹ h⁻¹ to 1.93 μg kg⁻¹ h⁻¹ and 2.12 μg kg⁻¹ h⁻¹, respectively, whereas lower concentrations (2 and 4.5 mg g⁻¹) increased emissions from 2.24 μg kg⁻¹ h⁻¹ to 2.95 μg kg⁻¹ h⁻¹ and 3.27 μg kg⁻¹ h⁻¹, respectively. Lower cycloheximide (2 and 4.5 mg g⁻¹) significantly enhanced N₂O emissions, reaching 9.15 μg kg⁻¹ h⁻¹ and 5.68 μg kg⁻¹ h⁻¹, respectively, whereas higher dosages (6 mg g⁻¹ and 10 mg g⁻¹) inhibited N₂O emissions, reducing them to 5.55 μg kg⁻¹ h⁻¹ and 4.84 μg kg⁻¹ h⁻¹, respectively. Carbon dioxide (CO₂) emissions generally decreased with increasing inhibitor dosages but significantly increased at 2 mg g⁻¹ and 4.5 mg g⁻¹ streptomycin. The inhibitors also altered soil N and carbon (C) dynamics, increasing ammonium (NH₄⁺-N), dissolved organic nitrogen (DON), and dissolved organic carbon (DOC) levels. Pearson correlation analysis indicated that N₂O emission was negatively correlated with cycloheximide dosage (R = −0.68, p < 0.001), NH₄⁺-N (R = −0.31, p < 0.001) and DOC content (R = −0.57, p < 0.05). These findings highlight the consequences of microbial disruption on N₂O emission and the complex microbial interactions in acidic soils. High concentrations of microbial inhibitors effectively reduce N₂O emissions by suppressing key microbial groups in nitrification and denitrification. Conversely, lower concentrations may prompt compensatory responses from surviving microorganisms, resulting in increased N₂O production. Future research should focus on sustainable management strategies to mitigate N₂O emissions while preserving the soil’s microbial community. Full article

As emerging economies play a pivotal role in global growth, understanding the impact of environmental factors, especially air pollution, on innovation is crucial. This study empirically examines the relationship between air pollution and innovation performance in EAGLE (emerging and growth leading economies) using a 20-year dataset (2000–2019) and employing 2SLS (two-stage least square) and FMOLS (fully modified ordinary least square) estimation techniques. The key findings of the study reveal that air pollution hampers R&D activities and patent applications by weakening human capital, diverting resources, and creating an unfavorable research environment. The results remain robust across multiple control variables and alternative estimation techniques. These findings highlight the urgent need for pollution control policies to mitigate its adverse effects on innovation, offering valuable insights for policymakers striving to enhance innovation resilience amid environmental challenges. This study uniquely explores the causal impact of air pollution on the macro-level innovation performance of a country. Full article

Microbial-induced calcium carbonate precipitation is an efficient and environmentally friendly soil stabilization technology. To explore the mineralization performance of carbonate precipitation, this study selects three factors, including the type of cementing solution (TCS), the cementing solution concentration (CSC), and the ratio of bacteria to cementing solution (B/C ratio), to investigate their effects on microbial mineralization. This study reveals the influence of each factor on the amount and rate of carbonate precipitation and analyzes the changes in the characteristics of carbonate precipitation crystals, such as the crystal diameter. The experimental results show that (1) the mineralization effect of magnesium ions and calcium ions results in higher precipitation amounts and rates than copper ions, with less environmental pollution. The concentration of the grout solution is positively correlated with the precipitation amount and negatively correlated with the precipitation rate, while the B/C ratio shows the opposite trend. (2) The crystal diameter of CaCO₃ between crystals reduces as the B/C ratio decreases and the CSC increases. (3) The characteristics of MgCO₃ crystals are mainly affected by the CSC. Both excessively high and low concentrations lead to an increase in crystal diameter. (4) The characteristics of CuCO₃ crystals are relatively stable, with smaller crystal particles maintained at around 1 μm. This study can provide a reference for the reinforcement of different types of soils, offering optimal reinforcement solutions based on the required crystal size, carbonate generation amount, and generation rate. It reduces resource waste and unnecessary chemical use, providing a theoretical foundation for sustainable soil remediation and ecological construction. Full article

The substitution of aluminum powder with highly reactive ultrafine aluminum-based metal fuels has a significant impact on the energy release of aluminum-containing energetic materials because of their excellent energy density and combustion performances. A series of ultrafine spherical Al-Mg alloy fuels with different contents of magnesium were prepared by close-coupled gas atomization technology. The properties of Al-Mg alloy powders of 13~15 μm were tested by SEM, TG-DSC, and laser ignition experiments. Results show that alloying with magnesium can significantly enhance thermal oxidation and combustion performance, leading to more oxidation weight gains and higher combustion heat release. HMX-based castable explosives with the same content of Al and the novel Al-Mg alloy were made and tested. Results show that the detonation performances of HMX/Al-Mg alloy/HTPB are better than HMX/Al/HTPB. Compared to the HMX/Al/HTPB explosive, the detonation heat of HMX/ Al-Mg alloy/HTPB was increased by 200 kJ/kg, the energy release efficiency was enhanced from 80.55% to 83.19%, the detonation velocity was increased by 114 m/s, and the shock wave overpressure at 5 m was increased by 83%. This research provides a new type of composite metal fuel for improving the combustion performance of Al powder. Full article

Needles play key roles in photosynthesis and branch growth in Larix olgensis. However, genetic variation and SNP marker mining associated with needle and branch-related traits have not been reported yet. In this study, we examined 131 samples of unrelated genotypes from L. olgensis provenance trails. We investigated phenotypic data for seven needle and one branch-related traits before whole genome resequencing (WGRS) was employed to perform a genome-wide association study (GWAS). Subsequently, the results were used to screen single nucleotide polymorphism (SNP) loci that were significantly correlated with the studied traits. We identified a total of 243,090,868 SNP loci, and among them, we discovered a total of 161 SNP loci that were significantly associated with these traits using a general linear model (GLM). Based on the GWAS results, Kompetitive Allele-Specific PCR (KASP), designed based on the DNA of population samples, were used to validate the loci associated with L. olgensis phenotypes. In total, 20 KASP markers were selected from the 161 SNPs loci, and BSBM01000635.1_4693780, BSBM01000114.1_5114757, and BSBM01000114.1_5128586 were successfully amplified, were polymorphic, and were associated with the phenotypic variation. These developed KASP markers could be used for the genetic improvement of needle and branch-related traits in L. olgensis. Full article

Mobile visible light communication (VLC) is key for integrating lighting and communication applications in the 6G era, yet there exists a notable gap in experimental research on mobile VLC. In this study, we introduce a mobile VLC system and investigate the impact of mobility speed on communication performance. Leveraging a laser-based light transmitter with a wide coverage, we enable a light fidelity (LiFi) system with a mobile receiving end. The system is capable of supporting distances from 1 m to 4 m without a lens and could maintain a transmission rate of 500 Mbps. The transmission is stable at distances of 1 m and 2 m, but an increase in distance and speed introduces interference to the system, leading to a rise in the Bit Error Rate (BER). The mobile VLC experimental system provides a viable solution to the issue of mobile access in the integration of lighting and communication applications, establishing a solid practical foundation for future research. Full article

Optical-based imaging has improved from early single-location research to further sophisticated imaging in 2D topography and 3D tomography. These techniques have the benefit of high specificity and non-radiative safety for brain detection and therapy. However, their performance is limited by complex tissue structures. To overcome the difficulty in successful brain imaging applications, we conducted a simulation using 16 optical source types within a brain model that is based on the Monte Carlo method. In addition, we propose an evaluation method of the optical propagating depth and resolution, specifically one based on the optical distribution for brain applications. Based on the results, the best optical source types were determined in each layer. The maximum propagating depth and corresponding source were extracted. The optical source propagating field width was acquired in different depths. The maximum and minimum widths, as well as the corresponding source, were determined. This paper provides a reference for evaluating the optical propagating depth and resolution from an optical simulation aspect, and it has the potential to optimize the performance of optical-based techniques. Full article

Pectobacterium brasiliense (Pbr) has caused significant economic losses in major vegetable production areas in Northern China by causing bacterial soft rot in cash crops such as potatoes and cucumbers. This study aimed to establish a PMA-qPCR detection method for Pbr by screening specific and sensitive primers based on the glu gene and the conserved region of the 23S rRNA gene. Based on the optimized PMA pretreatment conditions, a standard curve was designed and constructed for PMA-qPCR detection (y = −3.391x + 36.28; R² = 0.99). The amplification efficiency reached 97%, and the lowest detection limit of viable cells was approximately 2 × 10² CFU·mL⁻¹. The feasibility of the PMA-qPCR method was confirmed through a manually simulated viable/dead cell assay under various concentrations. The analysis of potato tubers and cucumber seeds revealed that nine naturally collected seed samples contained a range from 10² to 10⁴ CFU·g⁻¹ viable Pbr bacteria. Furthermore, the system effectively identified changes in the number of pathogenic bacteria in cucumber and potato leaves affected by soft rot throughout the disease period. Overall, the detection and prevention of bacterial soft rot caused by Pbr is crucial. Full article

Species diversity has been shown to be influenced by environmental factors, but the mechanism underlying their relationship remains unclear across spatial scales. Based on field investigation data collected from 3077 sample plots in temperate forest ecosystems, we compared tree species richness, evenness and dominance at 10 km × 10 km, 30 km × 30 km and 90 km × 90 km spatial scales. Then, we detected the scale dependence of changes in tree species composition on climate, topography and forest structure using variation partitioning and quantified their contribution to tree diversity with gradient–boosted models (GBMs) and fitted their relationships. The magnitude of tree richness, evenness and dominance significantly increased with spatial scale. Ecological factors jointly accounted for 24.3%, 26.5% and 38.5% of the variation in tree species composition at the three spatial scales, respectively. The annual mean temperature had a strong impact on tree richness, evenness and dominance and peaked at an intermediate scale. Tree evenness and dominance increased with the variation of temperature but had upper and lower limits. Tree richness obviously increased with annual precipitation on multiple scales and decreased with annual sunshine duration at large spatial scales. Tree richness, evenness and dominance obviously increased with the variation in elevation and diameter at breast height at large scales and small scales, respectively. Tree dominance decreased with tree height at a small scale. The dependence of tree diversity on ecological factors increased with spatial scales. Furthermore, different factors exert various controls on tree diversity at different spatial scales, representing a comprehensive mechanism regulating tree diversity. Full article

The purposes of this study are to reveal the spatial pattern and dynamic changes of NDVI in the northern slope of the Tianshan Mountains for an extended period and to explore whether the spatial and temporal evolution of NDVI in different spatial scales is consistent so as to provide a reasonable theoretical basis for the selection of appropriate remote sensing spatial resolution in the study area. The GIMMS NDVI remote sensing data set was used to resample the NDVI data with three spatial resolutions of 0.5 km × 0.5 km, 1 km × 1 km, and 8 km × 8 km. The Mann-Kendall method was used to analyze the spatial-temporal evolution characteristics of vegetation NDVI on the NTSM from 1981 to 2015. The results showed that the interannual variation trend and spatial distribution of vegetation NDVI were consistent at different spatial scales. The change of NDVI displayed an increasing trend with changes concentrated in the middle of the NTSM. Five distinct trends were observed: no significant change (35% of the area), significant positive change (26%), significant single peak change (15%), a significant U-shaped change relationship (12%), and significant negative change (11%). Remote sensing NDVI data with a spatial resolution of 8 km could be used to analyze the long-term interannual variation trend of vegetation NDVI on the NTSM. Full article

The introduction of visible light communication (VLC) technology could increase the capacity of existing wireless communication systems towards 6G networks. In practice, VLC can make good use of lighting system infrastructures to transmit data using light fidelity (Li-Fi). The use of semiconductor light sources, including light-emitting diodes (LEDs) and laser diodes (LDs) are essential to VLC technology because these devices are energy-efficient and have long lifespans. To achieve high-speed VLC links, various technologies have been utilized, including injection locking. Optical injection locking (OIL) is an optical frequency and phase synchronization technique that has been implemented in semiconductor laser systems for performance enhancement. High-performance optoelectronic devices with narrow linewidth, wide tunable emission, large modulation bandwidth and high data transmission rates are desired for advanced VLC. Thus, the features of OIL could be promising for building high-performance VLC systems. In this paper, we present a comprehensive review of the implementation of the injection-locking technique in optical communication systems. The enhancement of characteristics through OIL is elucidated. The applications of OIL in VLC systems are discussed. The prospects of OIL for future VLC systems are evaluated. Full article

The air-booster vacuum preloading method has been applied to slurry ground improvement. It is based on the conventional vacuum preloading method but with an additional injection of pressurised air into the soil via pre-installed conductors. The drainage effect of air-booster vacuum preloading has been demonstrated by past studies; however, direct observations of the real-time behaviour of slurries subjected to boosted air remain lacking. This study used a combined monitoring technique that included particle image velocimetry, pore water/air pressure gauges, a vortex flowmeter and an electronic balance to conduct a laboratory test of air-booster vacuum consolidation of dredged slurry. The tests allowed analyses of (1) the real-time displacement field of the slurry, (2) the pressure–flux relationship of the pressurised air, and (3) the pore water pressure responses during air boosting. The first aspect allowed direct observation of small-crack initialisation and propagation during pressurisation; while the latter two confirmed the crack initiation based on drops in air and pore water pressures. The measured crack initiation pressure was verified by comparison with theoretical predictions. The results demonstrate that pressurised air induces cracks in soil, which promote the drainage consolidation of dredged slurry. Full article

In the construction of large-scale water conservancy and hydropower transportation projects, the rock mass structural information is often used to evaluate and analyze various engineering geological problems such as high and steep slope stability, dam abutment stability, and natural rock landslide geological disasters. The complex shape and extremely irregular distribution of the structural planes make it challenging to identify and extract automatically. This study proposes a method for extracting structural planes from UAV images based on Geo-AINet ensemble learning. The UAV images of the slope are first used to generate a dense point cloud through a pipeline of SfM and PMVS; then, the multiple geological semantics, including color and texture from the image and local geological occurrence and surface roughness from the dense point cloud, are integrated with Geo-AINet for ensemble learning to obtain a set of semantic blocks; finally, the accurate extraction of structural planes is achieved through a multi-semantic hierarchical clustering strategy. Experimental results show that the structural planes extracted by the proposed method perform better integrity and edge adherence than that extracted by the AINet algorithm. In comparison with the results from the laser point cloud, the geological occurrence differences are less than three degrees, which proves the reliability of the results. This study widens the scope for surveying and mapping using remote sensing in engineering geological applications. Full article

The roles of medium- and long-chain triacylglycerols (MLCT) on health benefits under high fat diet (HFD) conditions remain in dispute. This study was conducted to investigate the effects of novel LaPLa-rich MLCT on the glycolipid metabolism and gut microbiota in HFD-fed mice when pork fat is half replaced with MLCT and palm stearin (PS). The results showed that although MLCT could increase the body weight in the mouse model, it can improve the energy utilization, regulate the glucose and lipid metabolism, and inhibit the occurrence of inflammation. Furthermore, 16S rRNA gene sequencing of gut microbiota indicated that PS and MLCT affected the overall structure of the gut microbiota to a varying extent and specifically changed the abundance of some operational taxonomic units (OTUs). Moreover, several OTUs belonging to the genera Dorea, Streptococcus, and g_Eryipelotrichaceae had a high correlation with obesity and obesity-related metabolic disorders of the host. Therefore, it can be seen that this new MLCT has different properties and functions from the previous traditional MLCT, and it can better combine the advantages of MLCT, lauric acid, and sn-2 palmitate, as well as the advantages of health function and metabolism. In summary, this study explored the effects of LaPLa-enriched lipids on glycolipid metabolism in mice, providing theoretical support for future studies on the efficacy of different types of conjugated lipids, intending to apply them to industrial production and subsequent development of related products. Full article

Ultrasonic (US) transducers have been widely used in the field of ultrasonic and photoacoustic imaging system in recent years, to convert acoustic and electrical signals into each other. As the core part of imaging systems, US transducers have been extensively studied and achieved remarkable progress recently. Imaging systems employing conventional rigid US transducers impose certain constraints, such as not being able to conform to complex surfaces and comfortably come into contact with skin and the sample, and meet the applications of continuous monitoring and diagnosis. To overcome these drawbacks, significant effort has been made in transforming the rigid US transducers to become flexible and wearable. Flexible US transducers ensure self-alignment to complex surfaces and maximize the transferred US energy, resulting in high quality detection performance. The advancement in flexible US transducers has further extended the application range of imaging systems. This review is intended to summarize the most recent advances in flexible US transducers, including advanced functional materials optimization, representative US transducers designs and practical applications in imaging systems. Additionally, the potential challenges and future directions of the development of flexible US transducers are also discussed. Full article