Search Results (1,167)

Floating rafts are thin, flat mineral layers that precipitate at still air–water interfaces. They are composed of calcite, aragonite, vaterite, gypsum, trona, carnallite, and/or halite. Floating rafts present a flat surface at the top in contact with air, and a rough surface at the bottom, which develops as they grow into the water. In this work, we describe floating rafts from hypersaline environments using imaging and analytical microscopy techniques. The four rafts studied consist of interconnected polycrystalline grains. Scanning electron microscopy (SEM) showed that the top surfaces were flat, whereas in the bottom surfaces, the grains protrude into the water. High magnification revealed nanoparticles arranged in stacks, suggesting growth through the organized agglutination of nanocrystals. Electron diffraction of two of the rafts indicates that they consist of aragonite. Accordingly, electron energy-loss spectroscopy (EELS) shows the C K-edges characteristic of carbonates, along with O and Ca edges. Energy-dispersive spectroscopy (EDS) in the SEM also revealed a few Ca sulfate crystals on the bottom surface. In addition, the presence of cubic shapes indicates the presence of halite. We hypothesize that the genesis of these rafts is driven by evaporation of still water, which increases supersaturation at the very surface, leading to mineral nucleation at the air–water interface, where the activation energy is lower. Full article

Floating seaweeds can be an effective dispersal vector for non-buoyant seaweeds. An under-explored aspect is the examination of seaweed rafts and their non-buoyant seaweed community after the floating journey ends. In this study, we analyzed 476 entire stranded specimens of the floating seaweed Durvillaea incurvata and their associated epiphytes, which were collected during winters and summers of 2023–2025 at four sites along the continental coast of Chile (between 31° S and 41° S). A total of 57 species of epiphytic seaweeds were found, with a higher predominance of Rhodophyta (71.9%). The most representative morpho-functional group was coarsely branched (29.1%). The species Lessonia spicata, Antithamnionella ternifolia, Corallina chilensis, Gelidium rex, G. chilense, and G. lingulatum were found frequently, and 67% of all epiphyte specimens found were reproductive. A higher taxonomic richness of epiphytes was observed at the southern-central sites compared to the northern site, being higher in summer than in winter. These results confirm that epiphytes associated with floating seaweeds are common and that many of these have reproductive structures. Co-occurrence analysis suggests that interactions among morpho-functional groups of epiphytes facilitate long-distance dispersal events. Future studies should assess the physiological viability and ability to reproduce of epiphytes after extensive floating journeys. This would contribute to understanding the effectiveness of rafting dispersal by floating seaweeds on the connectivity of raft-associated algal populations. Full article

Although neurons are not productively infected by HIV-1, the envelope glycoprotein gp120, detectable in cerebrospinal fluid independently of active viral replication, gains intraneuronal access via lipid raft-mediated endocytosis, macropinocytosis, and retrograde axonal transport, contributing to persistent neurobiological dysfunction within the central nervous system. Once internalized, gp120 is associated with neuronal dysfunction involving convergent pathways, including excitotoxic calcium dysregulation, mitochondrial and metabolic failure, and inflammatory and senescence-associated amplification. These pathways converge on suppression of CREB and BDNF signaling, dismantling the transcriptional and neurotrophic programs required for synaptic maintenance and cognitive resilience. Extracellular vesicle-mediated dissemination and microRNA reprogramming extend gp120-associated neurobiological effects beyond sites of receptor engagement, while gut-derived metabolites, particularly quinolinic acid, lower the excitotoxic threshold through synergistic activation of NMDA receptors. Together, these mechanisms define HAND as a network disorder in which gp120 contributes to persistent neurocognitive dysfunction beyond active viral replication, identifying convergent therapeutic nodes where combination strategies targeting excitotoxicity, mitochondrial dysfunction, and neuroinflammation offer the most promising path toward durable neuroprotection. Full article

Oxidative stress generates oxidized phospholipids (OxPLs) that alter membrane structure and inflammatory lipid signaling, yet the underlying biophysical mechanisms remain poorly understood. Here, we examine how two structurally distinct truncated oxidized phosphatidylcholines (OxPCs), 1-palmitoyl-2-(5′-oxo-valeroyl)-sn-glycero-3-phosphocholine (POVPC) and 1-palmitoyl-2-glutaryl-sn-glycero-3-phosphocholine (PGPC), remodel membrane lateral organization and regulate secretory phospholipase A₂ (sPLA₂) activity. Large unilamellar vesicles composed of sphingomyelin, cholesterol, and either monounsaturated 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) or polyunsaturated 1-palmitoyl-2-docosahexaenoyl-sn-glycero-3-phosphocholine (PDPC) were used to reconstitute the liquid-ordered/liquid-disordered (L_o/L_d) phase coexistence characteristic of eukaryotic plasma membranes. Fluorescence spectroscopy revealed that OxPLs modulate lipid packing and nanodomain organization in a structure- and composition-dependent manner. POVPC promoted pronounced membrane ordering and L_o domain stabilization compared with PGPC, particularly in monounsaturated membranes with low cholesterol content. In contrast, PDPC-containing membranes, especially at elevated cholesterol, exhibited enhanced structural resilience to OxPL-induced perturbations. These biophysical changes were associated with distinct functional outcomes. Notably, the relationship between membrane structural parameters and sPLA₂ activity was not linear, indicating a decoupling between bulk membrane properties and enzymatic response. sPLA₂ activity was linked to membrane lateral organization: the size of L_o domains modulate hydrolysis by influencing the physicochemical properties of L_o/L_d interfaces, which may represent preferential sites for enzyme activation. Consistent with this, POVPC reduced sPLA₂ activity through stabilization of ordered domains at both low and high cholesterol, while PGPC enhanced hydrolysis at high cholesterol. Importantly, PDPC-containing membranes attenuated sPLA₂ activity and exhibited a protective effect against OxPC-induced enzymatic activation. Together, these findings identify membrane lateral organization as a key regulator of sPLA₂ function and provide mechanistic insight into how oxidative stress can differentially modulate inflammatory lipid signaling depending on membrane composition. This work highlights membrane organization as an active determinant of enzyme activity and a potential target in pathologies associated with oxidative stress, including atherosclerosis, neuroinflammation, and metabolic disease. Full article

Arid Central Asia (ACA) is a major source of atmospheric dust in the Northern Hemisphere; however, the evolutionary models and driving mechanisms of Holocene aeolian activity in this region remain debated. Based on 13 reliable AMS ¹⁴C dates from the Sayram Lake SLM2009 sediment core, this study reconstructs the Holocene sequence in aeolian activity through end-member modeling analysis (EMMA). It evaluates its relationship with regional atmospheric circulation. Four end-members were identified from base to top: EM1, with a modal grain size of 7.58 μm, represents low-energy suspension deposition; EM2 (26.30 μm) reflects lacustrine hydrodynamic processes; while EM3 (52.48 μm) and EM4 (416.86 μm) serve as proxies for regional aeolian activity. The results indicate that aeolian activity was relatively strong during the early Holocene (reaching peaks at 11.7–11.2 and 9.2–8.1 cal ka BP), significantly intensified during the mid-Holocene (7.3–5.3 cal ka BP), and gradually weakened in the late Holocene (since 4.0 cal ka BP). Comparison of the aeolian record from Lake Sayram with Greenland ice cores, North Atlantic ice-rafted debris events, and the GISP2 K⁺ record indicates that variations in aeolian activity in arid Central Asia are closely linked to the Northern Hemisphere climate system. We propose that these variations were primarily modulated by large-scale atmospheric circulation, driven by the synergistic interaction between the Siberian High and the mid-latitude westerlies. Full article

Repurposing decommissioned wind turbine blades provides a vital pathway to mitigate carbon emissions, yet the escalating volume of large-scale waste poses a severe environmental challenge. Recognizing the limitation that existing research focuses predominantly on small-scale legacy blades, this study addresses this gap by assessing the mechanical properties and microstructure of a 54-m (2.0 MW) blade decommissioned due to repowering after 10 years of service. GFRP samples extracted from the root, mid-span, and tip were investigated using X-ray computed tomography and a comprehensive suite of mechanical tests. The investigation confirmed a low internal porosity (~1.2%) without service-induced macroscopic interfacial cracking, alongside superior residual performance, exemplified by a tensile strength of 849.5 MPa at the root. Statistical analysis employing ANOVA revealed significant spatial variations, supporting a graded reuse strategy: roots with superior tensile strengths for critical members, mid-spans for axial compression, and tips as a reliable property baseline for general reuse, while Weibull analysis verified the statistical reliability required for structural design. Based on these superior residual properties, a raft-type wave energy converter utilizing repurposed blade segments was proposed. A comparative carbon footprint assessment revealed that this blade-repurposed WEC achieved a 71.5% reduction in carbon emissions and a 37.4% reduction in structural mass compared to conventional steel counterparts. These findings substantiate the viability of large-scale DWTBs as high-value resources for decarbonizing marine infrastructure within a circular economy. Full article

To address the reduced accuracy of stereo matching networks near object boundaries and disparity discontinuities, a double cost–volume stereo matching network with entropy-difference-guided fusion is proposed. The proposed network was built based on RAFT-Stereo. It employs a pretrained backbone to extract multi-scale features and uses deformable attention for cross-scale feature fusion. A shallow image-guided branch was used to generate pixel-wise constraint information to limit the magnitude of sampling offsets and alleviate cross-structure sampling. Based on the extracted features, a group-wise correlation cost–volume and a normalized correlation cost–volume were constructed. Both cost–volumes were regularized by 3D Hourglass networks, and a structure-consistent intra-scale aggregation module was introduced during the regularization of the group-wise correlation cost–volume. The two aggregated results were then fused by the entropy-difference-guided fusion module to obtain the final cost–volume. The experimental results show the effectiveness of the proposed network in the Scene Flow, KITTI, and ETH3D datasets, achieving an endpoint error of 0.45 px and a >3 px error rate of 2.41% on the Scene Flow dataset. Full article

This review surveys how nanoparticles and biomolecular nanosized structures interact with model membrane systems, and how these interfacial processes govern their performance in drug and gene delivery, antimicrobial strategies, biosensing, and nanotoxicology. The nanostructures covered include polymeric nanoparticles, lipid-based carriers, peptide nanostructures, dendrimers, and multifunctional hybrids. Model membranes span Langmuir monolayers, supported lipid bilayers, vesicles/liposomes across sizes, and emerging hybrid or asymmetric constructs that better approximate native complexity. Mechanistically, interactions follow recurrent routes—surface adsorption, bilayer insertion, pore formation, and lipid extraction/reorganization—regulated by particle size, morphology, charge, ligand architecture, and lipophilicity, in conjunction with membrane composition, phase state, curvature, and asymmetry. A multiscale toolkit links structure, mechanics, and dynamics: Langmuir troughs and Brewster Angle Microscopy map thermodynamics and mesoscale morphology; atomic force microscopy and quartz crystal microbalance with dissipation resolve nanoscale topography and viscoelasticity; fluorescence microscopy/spectroscopy reports on localization and packing; neutron and X-ray reflectometry quantify vertical structure; molecular dynamics provides atomistic pathways and design hypotheses. Historically, the field advanced from early monolayers and bilayers, through the fluid mosaic model, to raft microdomains and modern biomimetic systems, enabling increasingly realistic experiments. Key advances include cross-method integration linking experimental observations with image-based computational models; persistent debates concern the translation from simplified models to living membranes, the role of dynamic coronas, and scale/force-field limits in simulations. Future efforts should prioritize hybrid models incorporating proteins and asymmetric lipidomes, standardized reporting and reference systems, rigorous coupling of experiments with calibrated simulations and machine learning, and alignment with safety-by-design and regulatory expectations, thereby shifting interfacial measurements from descriptive observation to predictive design rules. Full article

Drifting fish aggregating devices (DFADs) are central to tropical tuna purse-seine fisheries, yet their hydrodynamic performance under realistic seas has not been adequately addressed, particularly for emerging eco-friendly designs. A three-dimensional framework based on computational fluid dynamics is developed to assess the motion response and mooring loads of full-scale DFADs comprising raft buoys, biodegradable cotton rope, and iron sinkers, using four buoy layouts (Models A to D). Unsteady Reynolds-averaged Navier–Stokes (URANS) simulations are performed with a realizable k–ε closure, volume of fluid (VOF) free-surface capturing, the Euler overlay method, dynamic overset meshes, and catenary mooring coupling. Regular waves representative of operational conditions (T = 1.40 to 2.40 s, H = 0.10 to 0.40 m) are imposed via a VOF wave-forcing technique, and mesh/time-step sensitivity analyses demonstrate the accurate reproduction of the first-order wave elevation (error < 0.8%). Surge drift per cycle and heave response amplitude operators, with the relative mooring force, are evaluated as functions of the relative wavelength (λ/L_a) and wave steepness (H/λ). The results reveal that the buoy layout exerts first-order control on DFAD dynamics, whereas short, steep waves dominate motion and line loads. The intermediate end-point sinker mass achieves a favorable balance between motion suppression and mooring load control, whereas distributing a fixed total sinker mass along the rope reduces heave response and mooring force by improving the tension redistribution and overall stability. Across all sea states, Models A and D reduced motion envelopes and mooring forces, indicating their suitability as robust, low-impact configurations. The proposed framework and design recommendations provide quantitative guidance for optimizing eco-DFAD geometry and deployment strategies, supporting safer and more sustainable DFAD-based tuna fisheries. Full article

The interface between biomaterials and biological systems is crucial for medical implants and tissue engineering. Surface modifications are a key strategy for controlling interactions. Synthetic glycopolymers offer a versatile toolbox, mimicking the structure and function of natural glycoconjugates like mucins. This review highlights the significance of glycopolymers for targeted surface modifications of established biomaterials, such as silicones and poly(meth)acrylates. Controlled polymerization techniques, like the reversible-addition-fragmentation chain-transfer (RAFT) polymerization, enable the synthesis of well-defined glycopolymer architectures. Glycopolymeric surface functionalization creates tailored interfaces for different biological responses, from preventing protein and cell adhesion to promoting specific cell-type binding. The focus lies on using single, well-characterized polymeric base materials and tuning their surface properties through glycopolymer coatings to achieve various and specific functions. This approach opens new dimensions in the development of advanced biomaterials for applications like contact lenses, drug delivery systems, and biosensors and also possesses potential regulatory advantages by leveraging the safety profiles of existing materials. Full article

Eukaryotic microorganisms, including microalgae, protists, fungi, and micro-metazoans, act as drivers of energy flow and nutrient cycling, collectively forming the microbial food loop, and also serve as important indicators of environmental health. To investigate the seasonal variation in eukaryotic microorganisms in a mussel farming area, a total of 96 seawater samples were collected from surface and bottom layers of water across different seasons. High-throughput sequencing of the 18S rRNA gene was employed to characterize shifts in microbial community structure and identify key influencing factors. Our results indicated significant seasonal differences in eukaryotic microbial communities between surface and bottom waters. Redundancy Analysis (RDA) revealed that seasonal variations in community structure were primarily driven by environmental factors such as temperature, dissolved oxygen (DO), and salinity. Co-occurrence network analysis indicated that surface water networks exhibited higher numbers of nodes and edges, as well as greater modularity, suggesting more distinct niche differentiation and higher natural connectivity within the community. These findings provide fundamental data for understanding the response mechanisms of eukaryotic microbial communities to seasonal changes in the mussel cultivation area of Gouqi Island. Full article

Quantifying river surface flow velocity is essential for hydrodynamic modelling, flood forecasting, and water resource management. Traditional in situ methods provide accurate point measurements but are costly and limited in spatial coverage. Unmanned aerial vehicles (UAVs) offer a flexible, non-contact alternative for high-resolution monitoring. Optical flow is a tracer-independent technique for deriving velocity fields from RGB video, making it well suited to UAV-based surveys. However, its operational use is hindered by the limited availability of annotated datasets and by instability under low-texture or noisy conditions. This study combines a Finite element method (FEM)-based physical flow model with UAV video to generate reference datasets and introduces a modified Recurrent All-Pairs Field Transforms (RAFT) architecture based on multiframe sequences. A Gated Recurrent Unit fusion module (Fuse-GRU) is incorporated prior to correlation computation, improving robustness to illumination changes and surface homogeneity while maintaining computational efficiency. The proposed model delivers stable, physically consistent velocity estimates across multiple rivers and flow conditions. Accuracy improves with higher spatial resolution and moderate temporal spacing. Compared to field measurements, the average angular difference ranged from 8 to 15°. The high error values were mainly caused by inaccuracies in the physical model and by complex river features. These findings confirm that multiframe optical flow can reproduce realistic river flow patterns with accuracy comparable to physically-based simulations, thereby supporting UAV-based hydrometric monitoring and model validation. Full article

Apolipoprotein B mRNA editing enzyme catalytic polypeptide 3s (APOBEC3s, A3s) are single-stranded DNA cytidine deaminases with antiviral activity against diverse DNA and RNA viruses. The human APOBEC3 locus encodes seven members: A3A, A3B, A3C, A3D, A3F, A3G, and A3H. Of these, A3C, A3D, A3F, A3G, and A3H are packaged into HIV-1, lacking the viral infectivity factor (VIF, HIV-1Δvif), while A3D, A3F, A3G, and A3H hap II exhibit strong antiviral activity. Packaging of A3s into virions is critical for viral restriction, yet the underlying mechanisms remain incompletely understood. A3 incorporation requires interactions with the GAG polyprotein, especially the matrix (MA) and nucleocapsid (NC) domains, and binding to cellular or viral RNAs. Specific amino acid residues within A3 proteins mediate these contacts, and A3G localization to lipid rafts facilitates packaging. While A3F and A3G incorporation have been extensively characterized, mechanisms for other A3s remain poorly defined. This review synthesizes current knowledge on A3 packaging, emphasizing the interplay of protein, RNA, and membrane determinants in efficient virion incorporation. Full article

Extracellular vesicles (EVs), particularly exosomes, have emerged as critical mediators of intercellular communication, yet the metabolite fraction of their cargo remains substantially underexplored relative to proteins and nucleic acids. This review synthesizes current knowledge on the exosomal metabolome as a functionally distinct intercellular signaling system with unique biophysical properties. We review the mechanisms proposed to govern metabolite encapsulation into exosomes, encompassing membrane transporter involvement, lipid raft partitioning, and binding to luminal proteins, and discuss the unresolved question of whether metabolite loading is selective or stochastic. Critically, we present a quantitative framework evaluating whether delivered metabolite quantities are sufficient to alter recipient cell metabolic pools, distinguishing receptor-mediated signaling from bulk substrate delivery. We also address methodological considerations including contamination artifacts and isolation-method biases that complicate interpretation of EV metabolomics data. Exosomal metabolites are reviewed across four functional categories: energy substrates (ATP, lactate, amino acids), signaling molecules (TCA cycle intermediates, eicosanoids, nucleotides), redox cofactors and antioxidants (NADH, glutathione), and oncometabolites. For each category, available evidence is critically appraised, distinguishing metabolites with direct mass spectrometric detection from those whose roles are inferred from parent-cell biology. The review examines the roles of exosomal metabolites in tumor-stroma metabolic symbiosis, immunometabolic regulation, inter-organ crosstalk in metabolic diseases including type 2 diabetes and non-alcoholic fatty liver disease, cancer metastasis, viral infections, and immune evasion. A quantitative framework is discussed to evaluate whether delivered metabolite quantities are sufficient to alter recipient cell metabolic pools, distinguishing receptor-mediated signaling from bulk substrate delivery. Technical challenges in exosomal metabolomics are reviewed, including the impact of isolation method on data quality, contamination artifacts, and current standardization gaps. Therapeutic implications of exosomal metabolite signaling are discussed, encompassing metabolite-loaded exosomes as therapeutic vehicles and exosomal metabolite loading as a pharmacological target. Integration of single-vesicle technologies with systems biology approaches is highlighted as a promising direction for advancing this field toward precision medicine applications in oncological and metabolic disorders. Full article

Self-management plays an important role for students transitioning from elementary to secondary school, and yet many enter junior high lacking this ability. Although the problem is well known, there are limited theoretical models to inform adequate intervention. We tested the Socially Empowered Learning Framework (SELF) as a model for instructional design, asking if contexts associated with increased social empowerment create conditions for acquiring ability in self-management. We proposed that when social empowerment is established across a group there will be a positive association with individual levels of self-management within the group. To test this, we used a two-wave correlational pretest–posttest design with international data from 691 students. Findings from linear regression analyses support our hypothesis. Specifically, we found that social empowerment and self-management were significantly positively associated, with the greatest effect seen in students with low levels of self-management early in the year. Implications for theory and practice are discussed with recommendations for teacher effectiveness and student success. Full article