Search Results (229)

Inspection, maintenance, and repair (IMR) operations on underwater infrastructure remain costly and time-intensive because fully teleoperated remote operated vehicle s(ROVs) lack the range and dexterity necessary for precise cooperative underwater manipulation, and the alternative of using professional divers is ruled out due to the risk involved. This work presents and experimentally validates an autonomous, dual-I-AUV (Intervention–Autonomous Underwater Vehicle) system capable of assembling rigid pipeline segments through coordinated actions in a confined underwater workspace. The first I-AUV is a Girona 500 (4-DoF vehicle motion, pitch and roll stable) fitted with multiple payload cameras and a 6-DoF Reach Bravo 7 arm, giving the vehicle 10 total DoF. The second I-AUV is a BlueROV2 Heavy equipped with a Reach Alpha 5 arm, likewise yielding 10 DoF. The workflow comprises (i) detection and grasping of a coupler pipe section, (ii) synchronized teleoperation to an assembly start pose, and (iii) assembly using a kinematic controller that exploits the Girona 500’s full 10 DoF, while the BlueROV2 holds position and orientation to stabilize the workspace. Validation took place in a 12 m × 8 m × 5 m water tank. Results show that the paired I-AUVs can autonomously perform precision pipeline assembly in real water conditions, representing a significant step toward fully automated subsea construction and maintenance. Full article

To investigate the characteristics of rhizosphere soil microbial communities associated with Schisandra sphenanthera across different altitudinal gradients and to reveal the driving factors of microbial community dynamics, this study collected rhizosphere soil samples at four elevations: 900 m (HB1), 1100 m (HB2), 1300 m (HB3), and 1500 m (HB4). High-throughput sequencing and molecular ecological network analysis were employed to analyze the microbial community composition and species interactions. A null model was applied to elucidate community assembly mechanisms. The results demonstrated that bacterial communities were dominated by Proteobacteria, Acidobacteriota, Actinobacteriota, and Chloroflexi. The relative abundance of Proteobacteria increased with elevation, while that of Acidobacteriota and Actinobacteriota declined. Fungal communities were primarily composed of Ascomycota and Basidiomycota, with both showing elevated relative abundances at higher altitudes. Diversity indices revealed that HB2 exhibited the highest bacterial Chao, Ace, and Shannon indices but the lowest Simpson index. For fungi, HB3 displayed the highest Chao and Ace indices, whereas HB4 showed the highest Shannon index and the lowest Simpson index. Ecological network analysis indicated stronger bacterial competition at lower elevations and enhanced cooperation at higher elevations, contrasting with fungal communities that exhibited increased competition at higher altitudes. Altitude and soil nutrients were negatively correlated with soil carbon content, while plant nutrients and fungal diversity positively correlated with soil carbon. Null model analysis suggested that deterministic processes dominated bacterial community assembly, whereas stochastic processes governed fungal assembly. These findings highlight significant altitudinal shifts in the microbial community structure and assembly mechanisms in S. sphenanthera rhizosphere soils, driven by the synergistic effects of soil nutrients, plant growth, and fungal diversity. This study provides critical insights into microbial ecology and carbon cycling in alpine ecosystems, offering a scientific basis for ecosystem management and conservation. Full article

Arginine plays a critical role in biomolecular interactions due to its guanidinium side chain, which enables multivalent electrostatic and hydrogen bonding contacts. In this study, atomistic molecular dynamics simulations were conducted across a broad concentration range (26–605 mM) to investigate the thermodynamic and structural features of arginine self-assembly in aqueous solution. Key observables—including hydrogen bond count, radius of gyration, contact number, and isobaric heat capacity—were analyzed to characterize emergent behavior. A three-regime aggregation pattern (dilute, cooperative, and saturated) was identified and quantitatively modeled using the Hill equation, revealing a non-linear transition in clustering behavior. Spatial analyses were supplemented with trajectory-based clustering and radial distribution functions. The heat capacity peak observed near 360 mM was interpreted as a thermodynamic signature of hydration rearrangement. Trajectory analyses utilized both GROMACS tools and the MDAnalysis library. While force field limitations and single-replica sampling are acknowledged, the results offer mechanistic insight into how arginine concentration modulates molecular organization—informing the understanding of biomolecular condensates, protein–nucleic acid complexes, and the design of functional supramolecular systems. The findings are in strong agreement with experimental observations from small-angle X-ray scattering and differential scanning calorimetry. Overall, this work establishes a cohesive framework for understanding amino acid condensation and reveals arginine’s concentration-dependent behavior as a model for weak, reversible molecular association. Full article

The events of 2020 reached a fever pitch with the May 25th murder of George Floyd, but earlier on the same morning, a chance encounter between dogwalker Amy Cooper and birding enthusiast Christian Cooper also laid bare enduring social relations. As video footage of the encounter spread across social media, it sparked both public outrage and discourse regarding Black nature enthusiasts. Employing a historical-interpretive method informed by conversation analysis and guided by “whiteness as property,” I assemble news articles, social media posts, and video footage to analyze the events in Central Park and their aftermath. To unsettle existing paradigms regarding who we imagine are entitled to the great outdoors, I identify potential collaborative partners across scales who can further the goals of education, recruitment, and visibility for Black nature enthusiasts and professionals. I demonstrate how expanding environmental justice to include anti-Black racial violence allows us to recognize that the specter of lynching defies geographic boundaries, diffusing across space and time, occasionally coalescing to defend white privilege and historic racial orders. Full article

Motivated by the growth of global energy demand and the goal of carbon neutrality, lead-cooled fast reactors, which are core reactor types of fourth-generation nuclear energy systems, have become a global research hotspot due to their advantages of high safety, nuclear fuel breeding capability, and economic efficiency. However, its engineering implementation faces key challenges, such as material compatibility, closed fuel cycles, and irradiation performance of structures. This paper comprehensively reviews the latest progress in the core design of lead-cooled fast reactors in terms of the innovation of nuclear fuel, optimization of coolant, material adaptability, and design of assemblies and core structures. The research findings indicate remarkable innovation trends in the field of lead-cooled fast reactor core design, including optimizing the utilization efficiency of nuclear fuel based on the nitride fuel system and the traveling wave burnup theory, effectively suppressing the corrosion effect of liquid metal through surface modification technology and the development of ceramic matrix composites; replacing the lead-bismuth eutectic system with pure lead coolant to enhance economic efficiency and safety; and significantly enhancing the neutron economy and system integration degree by combining the collaborative design strategy of the open-type assembly structure and control drums. In the future, efforts should be made to overcome the radiation resistance of materials and liquid metal corrosion technology, develop closed fuel cycle systems, and accelerate the commercialization process through international standardization cooperation to provide sustainable clean energy solutions for basic load power supply, high-temperature hydrogen production, ship propulsion, and other fields. Full article

Glu-Phe-Asp (GFD) proteinoids represent a class of synthetic polypeptides capable of self-assembling into microspheres, fibres, or combinations thereof, with morphology dramatically influencing their electrical properties. Extended recordings and detailed waveforms demonstrate that microspheres generate rapid, nerve-like spikes, while fibres exhibit consistent and gradual variations in voltage. Mixed networks integrate multiple components to achieve a balanced output. Electrochemical measurements show clear differences. Microspheres have a low capacitance of $1.926\pm 5.735$$\mathsf{\mu }$F. They show high impedance at $6646.282\pm 178.664$ Ohm. Their resistance is low, measuring 15,830.739 ± 652.514 m$\mathsf{\Omega }$. This structure allows for quick ionic transport, leading to spiking behaviour. Fibres show high capacitance ($9.912\pm 0.171$$\mathsf{\mu }$F) and low impedance ($209.400\pm 0.286$ Ohm). They also have high resistance (163,067.613 ± 9253.064 m$\mathsf{\Omega }$). This combination helps with charge storage and slow potential changes. The 50:50 mixture shows middle values for all parameters. This confirms that hybrid electrical properties have emerged. The differences come from basic structural changes. Microspheres trap ions in small, round spaces. This allows for quick release. In contrast, fibers spread ions along their length. This leads to slower wave propagation. In mixed systems, diverse voltage zones emerge, suggesting cooperative dynamics between morphologies. This electrical polymorphism in simple proteinoid systems may explain complexity in biological systems. This study shows that structural polymorphism in GFD proteinoids affects their electrical properties. This finding is significant for biomimetic computing and sheds light on prebiotic information-processing systems. Full article

Benthic microbial communities are a vital component of coastal subtidal zones, playing an essential role in nutrient cycling and energy flow, and are fundamental to maintaining the stability and functioning of marine ecosystems. However, the response of benthic prokaryotic and eukaryotic microbial communities to environmental changes remains poorly understood. Herein, we conducted a nearly semimonthly annual sampling survey to investigate the temporal patterns and underlying mechanisms of benthic prokaryotic and eukaryotic microbial communities in the subtidal sediments of Sanshan Island, situated in the eastern Laizhou Bay of the Bohai Sea, China. The results showed that the temporal variations in benthic microbial communities followed a distinct seasonal pattern, with turnover playing a more dominant role in community succession. Nonetheless, contrasting temporal variations were observed in the alpha diversity of benthic prokaryotic and eukaryotic microbial communities, as well as in the dominant taxa across different microbial communities. Water temperature, dissolved oxygen, electrical conductivity, salinity, total nitrogen (TN), NH₄⁺, and PO₄³⁻ were identified as the predominant environmental drivers. The assembly of benthic microbial communities was driven by different ecological processes, in which stochastic processes mainly shaped the benthic prokaryotic communities, while deterministic processes dominated the assembly of benthic eukaryotic microbial communities. Interactions within benthic microbial communities were primarily characterized by mutualistic or cooperative relationships, but the ability of prokaryotic and eukaryotic microbial communities to maintain stability under environmental disturbances showed notable differences. These results shed light on the temporal dynamics and potential driving mechanisms of benthic prokaryotic and eukaryotic microbial communities under environmental disturbances, highlighting the distinct roles of prokaryotic and eukaryotic communities in coastal subtidal zones and providing valuable insights for the management and conservation of coastal subtidal marine ecosystems. Full article

Structural analyses of protein filaments formed by self-assembly, such as actin, tubulin, or recombinase filaments, have suffered for decades from technical issues due to difficulties in crystallization, their large size, or the dynamic behavior inherent to their cellular function. The advent of cryo-electron microscopy has finally enabled us to obtain structures at different stages of the existence of these filaments. However, these structures correspond to frozen states, and the possibility of observations in solution is still lacking, especially for filaments characterized by a high plasticity, such as the RecA protein for homologous recombination. Here, we use a combination of SAXS measurements and integrative modeling to generate the solution structure of two known forms of the RecA nucleoprotein filament, previously characterized by electron microscopy and resolved by X-ray crystallography. The two forms differ in the cofactor bound to RecA–RecA interfaces, either ATP or ADP. Cooperative transition from one form to the other has been observed during single-molecule experiments by pulling on the filament but also in solution by modifying solvent conditions. We first compare the SAXS data against known structural information. While the crystal structure of the ATP form matches well with the SAXS data, we deduce from the SAXS profiles of the ADP-form values of the pitch (72.0 Å) and the number of monomers per turn (6.4) that differ with respect to the crystal structure (respectively, 82.7 Å and 6.0). We then monitor the transition between the two states driven by the addition of magnesium, and we show this transition occurs with 0.3 mM Mg ²⁺ ions with a high cooperativity. Full article

Straw application (SP) is a promising strategy for the improvement of soil fertility, but the biological effects and the mechanisms of its effects on microorganisms remain unclear. The investigation into the tea plantations (CK/S) in southern Henan, China, without/with straw amendment was carried out to assess the effects of SP on the soil bacterial communities using high-throughput sequencing. SP induced the community restructuring of the dominant phyla, e.g., Acidobacteriota, Pseudomonadota, Chloroflexota, with significantly increasing Nitrospirota, Vicinamibacterales and Anaerolineaceae (p < 0.05), while reducing Terriglobales (p < 0.05). These transitions correlated with significantly enhanced α-diversity and β-diversity divergence (p < 0.05). The linear discriminant analysis effect size (LEfSe) results confirmed the significant selective enrichment of nitrogen-cycling taxa (Nitrospira), copiotrophs (Chryseotalea), and anaerobic degraders (Anaerolineaceae), along with the suppression of the oligotrophic lineage (Ellin6067) by SP (p < 0.05). The co-occurrence networks of S had lower topological properties and negative cohesion (p < 0.05), which exhibited intensified simplified complexity and competition. The soil water content (WC) and pH were the main drivers of β-diversity variation and the keystone taxa assembly, as calculated out by distance-based redundancy analysis (dbRDA). This study demonstrates that SP can enhance bacterial network stability and functional redundancy by resource-driven niche partitioning between copiotrophic taxa and nitrogen-cycling guilds through a competition–cooperation equilibrium. Full article

Ribosomal proteins (RPs) were traditionally considered as ribosome building blocks, serving exclusively in ribosome assembly. However, contemporary research highlights their involvement in additional translational roles, as well as diverse non-ribosomal activities. The functional diversity of RPs is further enriched by the presence of 2–7 paralogs per RP family in plants, suggesting that these proteins may perform distinct, specialized functions. The spatiotemporal expression of RP paralogs allows for the assembly of unique ribosomes (ribosome heterogeneity), enabling the selective translation of specific mRNAs, and producing specialized proteins essential for plant functioning. Additionally, RPs that operate independently of ribosomes as free molecules may regulate a wide range of physiological processes. RPs involved in protein biosynthesis within the cytosol, mitochondria, or plastids are encoded by distinct genes, which account for their functional specialization. Notably, RPs associated with plastid or mitochondrial ribosomes, beyond their canonical roles in these organelles, also contribute to overall plant development and functionality, akin to their cytosolic counterparts. This review explores the roles of RPs in different cellular compartments, the presumed molecular mechanisms underlying their functions, and the involvement of other molecular factors that cooperate with RPs in these processes. In addition to the new RP nomenclature introduced in 2022/2023, the old names are also applied. Full article

The development of self-assembled multicatalytic systems has emerged as a promising strategy for mimicking enzymatic catalysis in synthetic systems. This approach leverages the use of non-covalent interactions, such as hydrophobic interactions, hydrogen bonding, metal–ligand coordination, and aromatic stacking, to organize multiple catalytic centers within a defined, cooperative framework, allowing for enhanced reactivity, selectivity and efficiency, akin to the behavior of natural enzymes. The versatility of this approach enables the modular design, preparation, screening and optimization of systems capable of concerted catalysis and dynamic adaptation, making them suitable for a wide range of reactions, including asymmetric synthesis. The potential of these systems to emulate the precision and functionality of natural enzymes opens new avenues for the development of artificial multicatalytic systems with tailored and adaptable functions. Full article

The aim of the study is a multi-criteria comparative evaluation of robots cooperating with humans in single- and dual-arm variants used for the process of precise assembly of complex parts. RobotStudio simulation software with the Signal Analyzer add-on was used for comparative analyses. These studies were conducted as case studies. A robotic station was designed for the assembly of a computer motherboard and two robot variants were programmed to perform the assembly task while maintaining the same motion parameters and functions for both. Then, the TCP motion trajectories associated with the robot were analyzed, as well as monitoring signals from the robot controller during simulation, such as time, speed, acceleration and energy consumption. The costs and profitability of the robot variants were also calculated. The percentage share of tasks performed in the process was also analyzed, divided into assembly tasks and free movements. The differences between the robots in this process include time, 21 s single-arm versus 14 s dual-arm robots. The main influence on achieving the programmed speed was the length of the robot’s TCP motion path. In most cases, the maximum programmed speed of 200 mm/s was achieved. The single-arm robot proved to be more energy-efficient, but the dual-arm robot proved to be 20% faster, which in the long run proved to be a more profitable robot. The profitability of the dual-arm robot paid off after eight months of operation. The case study presented in this paper, assembling a computer motherboard using single- and dual-arm collaborative robots, provides a guide for conducting similar comparative analyses of different robotic stations. Simulations enabled reliable verification of collaborative robots in technological processes, supporting the design of production processes and the analysis of several variants of robotic solutions. Full article

Global warming has intensified the changes in wetland carbon cycling processes, and the cbbL gene, which plays a key role in carbon fixation, is significantly affected by warming. Therefore, we set up open-top chamber warming and natural controls and used amplicon sequencing to investigate the response of the cbbL carbon-fixing microbial community in the alpine lakeshore wetland to warming. We found that after the warming treatment, the relative abundances of Actinobacteria and Chlorophyta increased, while the relative abundance of Cyanobacteria decreased (p < 0.05). Soil temperature and moisture were the most significant factors influencing the cbbL carbon-fixing microbial community in the lakeshore wetland. Deterministic processes dominated the community assembly of carbon-fixing microbes under warming conditions. Additionally, warming enhanced both cooperative and competitive interactions among carbon-sequestering microorganisms while reducing soil moisture availability and increasing environmental stress, leading to a decrease in the modularity of microbial communities. In summary, warming reduced the carbon sequestration potential of lakeside wetlands but favored the interactions among carbon-sequestering microorganisms. Full article

Traditional manual assembly is limited in terms of both efficiency and quality. In contrast, robots are characterized by rapidness and accuracy and can cooperate with humans to perform complex tasks. Human–robot collaboration may hold the potential to enhance the manufacturing capacity of the helicopter industry. However, the traditional assembly process design methods based on personal experience can hardly adapt to the transformation of manufacturing mode, which makes deploying human–robot collaborative assembly inefficient. In this paper, we systematically analyze applications of human–robot collaboration in helicopter fuselage assembly. Concretely, an automatic drilling and riveting process based on human–robot collaboration is designed and verified. Moreover, we develop an intelligent process design prototype system that is specifically designed for human–robot collaborative assembly by modeling and integrating process knowledge. It can effectively assist human designers by means of recommending equipment selection, process parameters, and numerical control programs. Taking a fuselage assembly process design as an example, we verify that the prototype system can improve both the management of process knowledge and the efficiency of process design. Full article

The biochemical degradation of abundant cellulosic biomass for industrial use and energy production has been extensively researched in recent years. Some elaborate cellulose digestion approaches have been developed based on specialized bacteria, which possess sophisticated mechanisms to efficiently degrade recalcitrant natural carbohydrates. In this study, we assembled catalytic domains from multiple cellulolytic enzymes onto a scaffold along with a cellulose-binding module (CBM), specifically targeting crystalline cellulose. The catalytic domains of endoglucanase and cellobiohydrolase from Acetivibrio thermocellus were linked to a heterotrimeric protein scaffold that assembles in a specific order. The bicatalytic complex failed to show the anticipated synergistic effect in cooperative cellulolysis, presumably because the catalytic domains only serve as weak anchors for each other in binding to the substrate. On the other hand, cellulose digestion was remarkably promoted by incorporating a CBM into a stable complex with a catalytic domain. Interestingly, the reversible association of catalytic domains and excess CBM proved more advantageous than fixed association. This suggests that the dynamic incorporation of CBM units enhances the accessibility of cellulose-degrading catalytic modules to the polysaccharide strand by preventing overly strong binding. This finding could have interdisciplinary applications for enzymes converting polymeric substrates other than cellulose. Full article