Search Results (490)

Noble metal nanostructures provide versatile platforms for light manipulation through localized surface plasmon resonances (LSPRs). Among them, triangular silver nanoplates (AgNPTs) exhibit strong field-enhancement and spectral tunability, yet assembling them reproducibly on solids is challenging. We report a two-step functionalization strategy for constructing ordered AgNPT dimers on silica substrates, combining 3-aminopropyltriethoxysilane (APTES) anchoring with 1,4-butanedithiol bridging. AFM reveals face-to-face dimers with well-defined sub-nanometer gaps. Large-area AFM statistics collected over multiple regions (N = 80 nanoplates per condition) confirm reproducible and selective vertical dimerization. Extinction spectroscopy reveals sequential dielectric and coupling effects: thiol adsorption red-shifts the main resonance from 700 to 780 nm because of increased local refractive index and near-field damping, whereas dimerization partially restores it to ≈750 nm, consistent with plasmon hybridization within rigid ∼0.7 nm molecular gaps, where nonclassical moderation may occur but classical hybridization fully explains the observed shifts. Concomitantly, the extinction intensity doubles, following an exponential growth toward saturation during assembly. Surface-enhanced Raman scattering (SERS) measurements using 4-mercaptobenzoic acid (4-MBA) confirm a fourfold increase in the SERS enhancement factor from monolayer to bilayer, consistent with near-field coupling and hotspot formation at interplate junctions. Quantitative plasmon sensitivity analysis yields comparable results between experiments and finite-difference-time-domain simulations, confirming that the observed spectral shifts arise from near-field coupling and dielectric modulation rather than ensemble effects. This reproducible methodology enables precise tuning of NPT orientation, spacing, and optical response, providing a robust platform for enhanced sensing, SERS, and nanophotonic device engineering. Full article

The crystal structure regulation of Ti₃O₅ by Al₂O₃ doping and its effect on the optical properties of TiO₂ films prepared by electron beam evaporation were systematically studied. Ti₃O₅ coating materials with different Al₂O₃ doping contents (0–50 at%) were prepared by vacuum melting, and the corresponding TiO₂ films were deposited on K9 glass substrates via electron beam vacuum evaporation. The phase structure, phase transition temperature, chemical composition and optical properties of the materials and films were characterized by XRD, DSC, EDS, XPS, UV-Vis and AFM. Results show that Al₂O₃ doping induces the phase transition of Ti₃O₅ from a room-temperature stable β-phase to a high-temperature stable λ-phase, with complete transition at 5 at% doping. Al³⁺ with a smaller ionic radius causes lattice contraction and local distortion of Ti₃O₅, enabling stabilization at room temperature of the λ-phase. For TiO₂ films, 12.5 at% doping is the optimal state with the stable composition transfer under this condition. With the increase in Al₂O₃ doping content, the refractive index and extinction coefficient of TiO₂ films decrease continuously, while the optical band gap and surface roughness show an increasing trend. The changes in optical properties are mainly ascribed to the low refractive index of Al₂O₃, lattice compressive strain effect and oxygen vacancy passivation induced by Al³⁺. This study clarifies the regulation effect of Al₂O₃ doping on Ti₃O₅ phase transition and TiO₂ film optical properties, and provides theoretical basis and experimental reference for the doping modification of TiO₂ films and their practical applications in consumer electronics and optical filter devices. Full article

Directly modulated VCSEL transmitters are widely deployed in short-reach optical interconnects. However, further scaling of per-lane symbol rates in AI/HPC data center fabrics requires modulation schemes beyond the practical limits of direct current modulation. We demonstrate a laterally integrated VCSEL–electro-absorption modulator (EAM) transmitter enabled by resonance-detuned coupling on an oxide-confined half-VCSEL platform. A localized 20 nm surface etch produces > 5 nm resonance detuning, confirmed by measured spectra and supported by transfer-matrix and mode-matching simulations, which indicate strong slow-light-assisted lateral coupling into the modulator. Experimentally, the measured spectra confirm a 5 nm resonance separation. Static characterization shows a coupling ratio of 63% extracted from near-field profiles and an extinction ratio of 4 dB (based on modulator-side power) under a −2 V modulator bias, with an apparent 1 mW absorption at a 6 mA VCSEL drive current. Dynamic measurements demonstrate a small-signal 3 dB bandwidth of approximately 23 GHz and clear NRZ eye openings at 25 Gbps and 30 Gbps. These results validate resonance-detuned lateral integration as a compact and manufacturable approach to VCSEL-based externally modulated transmitters for next-generation short-reach interconnects. Full article

Bodanella lauterborni W.M. Zimmermann and Heribaudiella fluviatilis (Areschoug) Svedelius are members of brown algae (Phaeophyceae) that exclusively inhabit freshwater habitats. Heribaudiella fluviatilis is the most frequently reported freshwater brown alga, widely distributed in the Northern Hemisphere. In contrast, B. lauterborni, one of the rarest algae globally, has been reported in only four glacial Alpine lakes and has not been observed in nature for nearly 50 years. Since 2019, the species has been considered locally extinct at its type locality, and its presence in the other three lakes is also questionable. Here, we report the occurrence of B. lauterborni in three springs on the Vlasina Plateau (Southeast Serbia), being the first finding of the species in Southeast Europe and the fifth discovery globally in environmental conditions not previously described for the species. We also provide detailed data on the morphology, ecology, and biogeography of B. lauterborni and H. fluviatilis. Additionally, we report the non-obligate association Hildenbrandio rivularis-Heribaudielletum fluviatilis discovered in two rivers. Our findings significantly expand the known ecological and geographical range of phaeophytes, highlighting Southeast Europe as a refugium for freshwater Phaeophyceae biodiversity. Full article

Earthworms are ecosystem engineers that are sensitive to land-use intensification and edaphic conditions, yet their ecology remains poorly understood in transformed semi-arid landscapes. We hypothesized that, in recently colonized agroecosystems, land-use intensity and physicochemical soil conditions jointly filter the earthworm assembly. In the recently irrigated Lower Valley of the Negro River, Patagonia, Argentina, we sampled earthworms and soils across five land uses—riparian reference sites, fruit orchards, pastures, cereal crops, and horticulture plots—in landscapes dominated by Natrargid Ustolls and Fluventic Haplocambids. We found five species, all of which were exotic Lumbricidae, including the first Argentine record for Murchieona minuscula, indicating a recent colonization following human-mediated niche construction that created an ecological island. The earthworm abundance and biomass were highest in permanent and semi-permanent uses and were driven primarily by soil moisture, pH, and particulate organic matter. Crucially, our results reveal that land-use intensity filters communities by restricting the initial colonization rather than through local extinctions. These findings confirm that soil properties mediate the impact of land use on earthworm assemblages. The inclusion of pastures and fruit orchards in the rotations favors the earthworm populations that, despite low diversity, enhance soil functioning and contribute to agricultural sustainability in semi-arid irrigated agroecosystems. Full article

Branching processes are stochastic models describing the evolution of populations in which individuals reproduce and die independently over time. In the classical setting, an individual’s reproductive capacity is fixed throughout its lifetime. However, in real-world situations, fertility typically rises during a juvenile phase, peaks at maturity, and subsequently declines. In order to capture this feature, we introduce a branching random walk with ageing, as an extension of the classical branching random walk, by assigning each individual an age-dependent reproductive rate. Our model differs from classical age-dependent processes such as the Bellman–Harris model, where the remaining lifespan depends on age, while the rate of reproduction is fixed within that lifetime. As in the classical case, branching random walks with ageing are parametrised by $\lambda >0$, which tunes the reproductive speed and may be seen as a characteristic of the population. The thresholds of $\lambda$ separating extinction and survival are the global and local critical parameters. We characterise the value of the local critical parameter and provide a lower bound for the global critical parameter. We identify a class of ageing branching random walks for which this lower bound coincides with the global critical parameter. We study how local modifications to the reproduction and ageing rates may change the critical parameters. This is of practical interest: in species preservation, one may want to lower the critical parameters, so that $\lambda$ exceeds them, and there is a positive probability of survival. On the other hand, in epidemic control, the goal is to increase the critical parameters, since if $\lambda$ is below them, then the epidemic is eventually going to disappear. We compute the expected number of individuals alive in a branching process with ageing and show that, contrary to the behaviour of classical branching processes, it may exhibit an initial growth even when the population is ultimately destined for extinction. Full article

In the field of digital architectural heritage, the mining of tacit local knowledge embedded in architectural heritage is considered essential for the preservation, inheritance, and application of regional architectural characteristics. Local knowledge can be formally represented through semantic models, by which the automated mining of tacit information can be facilitated. However, due to the incomplete preservation of physical buildings and the fragmented nature of historical records, local knowledge is often represented as semantic fragments. Consequently, existing semantic models are still challenged in terms of knowledge integration and reasoning. In this study, a knowledge graph was developed for representing local knowledge, in which fragmented local semantics were aligned at both the ontological and entity levels. Subsequently, implicit local knowledge mining is achieved through meta-path centrality propagation combined with expert evaluation on a graph visualization platform. The method was applied to eight historical buildings in a case study. The knowledge graph quality assessment results indicate excellent ontology utilization and property utilization. The knowledge mining results demonstrate that graph-based expert evaluation successfully enables knowledge Feature Ranking and knowledge Extinction Warning. Full article

The α-gal epitope is synthesized in non-primate mammals and New-World monkeys by the glycosylation enzyme α1,3galactosyltransferase (α1,3GT), encoded by the GGTA1 gene. Ancestral Old-World monkeys and apes synthesizing α-gal epitopes underwent extinction 20–30 million years ago. Their mutated offspring, with the inactivated GGTA1 gene, survived and produced the natural anti-Gal antibody, specifically binding α-gal epitopes. Anti-Gal protected the surviving offspring from lethal viruses presenting α-gal epitopes, which killed α-gal-synthesizing parental primates. Anti-Gal constitutes ~1% of human immunoglobulins and is also produced in Old-World monkeys and apes. α-Gal epitopes can serve as therapeutic agents in several clinical disciplines: 1. Cancer immunotherapy: Engineering cancer cells to express α-gal epitopes results in anti-Gal binding to these cells and localized activation of the complement system that kills these cancer cells and recruits the antigen-presenting cells (APCs) dendritic cells and macrophages. Anti-Gal bound to cancer cells targets them for robust uptake by APCs, which process internalized tumor antigens (TAs) and transport them to lymph nodes for activation of cytotoxic T-cells. These T-cells kill TA-presenting metastatic tumor cells. Clinical trials demonstrated that such engineering is achieved by intra-tumoral injection of α-gal glycolipids, the use of recombinant α1,3GT, or the use of oncolytic viruses containing the GGTA1 gene. 2. Viral vaccines: Inactivated whole-virus vaccines presenting α-gal epitopes bind anti-Gal, which targets them for extensive uptake by APCs, thereby increasing their immunogenicity by ~100-fold. 3. Injured-tissue regeneration: Anti-Gal binding to α-gal-presenting nanoparticles administered to wounds, into the post-myocardial infarction (MI) injured myocardium and into injured spinal cord, activates the complement system that recruits pro-regenerative macrophages, which orchestrate regeneration by recruiting stem cells and the secretion of pro-regenerative cytokines. All these findings suggest that α-gal/anti-Gal antibody interaction can serve as a novel therapeutic approach, applicable to various clinical settings. Full article

Background/Objectives: Habitat degradation and fragmentation reduce population size, genetic diversity, and connectivity, increasing extinction risk in small and isolated populations. Coastal wetlands of northwestern Peru have undergone extensive anthropogenic modification, yet the genetic and ecological status of resident carnivore populations remains poorly documented. This study aimed to assess genetic diversity, relatedness, demographic signals, and diet composition of a Pampas cat (Leopardus garleppi) population inhabiting the Mangroves San Pedro de Vice (MSPV), a Ramsar-listed coastal wetland. Methods: We combined noninvasive fecal genotyping using eight nuclear microsatellite loci with vertebrate DNA metabarcoding. Scat samples were collected across three field seasons (2019–2021). Individual identification, genetic diversity metrics, genetic mark–recapture estimation of census size (Nc), effective population size (Ne), bottleneck tests, and relatedness analyses were performed to evaluate population status and kin structure. Dietary composition was characterized using metabarcoding and assessed for sex-specific differences. Results: Sixty-eight scats yielded multilocus genotypes for nine individuals (six males, three females). Genetic analyses revealed moderate diversity (mean allelic richness = 3.47; observed heterozygosity = 0.69; expected heterozygosity = 0.58) and evidence consistent with a recent genetic bottleneck. Genetic mark–recapture analyses estimated a small census size (Nc = 9; 95% CI: 7.0–9.0), while the effective population size was markedly low (Ne = 2.4; 95% CI: 1.5–7.4), yielding an Ne/Nc ratio of ~0.27. Multiple first-order kin dyads were detected, indicating strong local kin structure and limited external recruitment. Metabarcoding identified eight vertebrate prey species, with diet dominated by the native rodent Aegialomys xanthaeolus. No significant sex-specific differences in diet composition were detected. Conclusions: The MSPV Pampas cat population represents a small, kin-structured range-edge population showing signatures consistent with recent genetic erosion and restricted connectivity. These patterns align with isolation in a degraded coastal wetland landscape, highlighting the importance of habitat protection, prey resource conservation, and restoration of functional connectivity to support long-term population persistence. Full article

Y₂O₃ is widely used in IR windows and optoelectronics, but its vibrational and spectral properties under La³⁺ substitutions remain unclear. This work investigates xLa₂O₃-(1−x)Y₂O₃ with x = 0–0.2 via XRD, SEM, Raman, and IR spectroscopy to address the lack of comprehensive data on structure–property correlations. The solid solution (Y_1−xLa_x)₂O₃ with 0 ≤ x < 0.15 was determined. The cell parameter a increases from 10.6113(5) Å to 10.7116(1) Å as x increases from 0 to 0.15 according to the Rietveld refinements. Both the Raman spectra and infrared (IR) reflection spectra show that (Y_1−xLa_x)₂O₃ is a “one-mode” system, in which eight of the 22 theoretical first-order Raman modes and 12 of 16 theoretical IR modes for the (Y_1−xLa_x)₂O₃ are recognized. A local vibrational mode at approximately 680 cm⁻¹ is observed in the Raman spectra as x > 0. The Raman modes and IR modes of (Y_1−xLa_x)₂O₃ show red shift and obvious peak broadening as x increases, which is caused by the expansion of unit cell and local distortions of the crystal structure. As Y³⁺ is substituted by La³⁺, the extinction coefficient κ decreases significantly, which can lead to a lower IR absorption and should be beneficial for the IR window applications. Full article

An experimental study was conducted to quantitatively assess the separate effects of smoke-layer height and temperature on fire spread along a cable tray in a compartment. Smoke-layer height was controlled by varying the opening height (h) using side-wall configurations (SW0%, SW25%, and SW50%), while smoke-layer temperature was adjusted by changing the heat release rate (HRR) of an LPG burner (10, 14, and 18 kW). Fire spread was quantified using flame imaging and measurements of HRR, fire growth and spread rates, incident heat flux at tray height, and gas temperature and O₂ concentration above and below the tray. At 10 kW, self-extinction occurred before the flame reached the tray end for all side-wall configurations. At 14 and 18 kW, fire spread to the tray end occurred under SW25% and SW50%. For a given HRR, SW50% produced higher heat flux and temperature near the tray but lower oxygen concentration, especially below the tray. These findings indicate that cable tray fire spread is governed by the combined effects of smoke-layer height and temperature through thermal feedback and local oxygen availability. Fire spread was promoted by stronger thermal feedback, but could be limited under a deeper smoke layer when oxygen availability near the tray was reduced. Full article

The paper develops a coarse-grained framework for computing mean extinction times in multi-metastable systems modeled as one-step continuous-time Markov chains with an absorbing state. At the microscopic level, backward equations on finite corridors are solved to obtain closed-form series for committors, mean first-passage times, and intrawell (basin) waiting times. A renewal–reward construction then yields effective interwell transition rates written as a success probability divided by a mean cycle duration, providing an interpretable effective rate constant. These rates define a reduced Markov chain on the wells together with extinction; mean extinction times follow from a linear system, and the associated fundamental matrix quantifies pre-extinction residence times in each coarse state. This framework makes explicit how multiple escape pathways and intrawell dwell times contribute to extinction statistics in finite systems. The method is illustrated on a double-well landscape with an extinction state, using a reversible potential-to-rates mapping for the numerical example. Comparisons of alternative intrawell models and validation against exact one-step computations demonstrate accuracy at finite system sizes, including regimes where diffusion approximations are unreliable. The resulting formulas require only local rate data, remain numerically stable under strong bias, and extend directly to multiple wells and flexible boundary conditions. Full article

Advances in high-performance computing have expanded the use of computational fluid dynamics (CFD) for reacting-flow analysis; however, simulations involving detailed flame kinetics remain computationally intensive for many practical systems. Efficient modeling approaches are therefore essential for predicting flame behavior in swirl-stabilized combustors. This study examines the influence of main-stage swirl intensity on near-lean blow-off characteristics in a multistage swirl combustor using a hybrid RANS–LES framework. The Stress Blended Eddy Simulation (SBES) model, coupled with a Flamelet Generated Manifold (FGM) combustion formulation, is employed to capture key turbulence–chemistry interactions. Results indicate that reducing swirl intensity suppresses the formation of a swirl-stabilized flame, while excessive swirl negatively affects emission performance. For the baseline (S2) and high-swirl (S3) configurations, flame lift-off height increases by 21.0% and 11.96%, respectively, for every 0.1 reduction in equivalence ratio. The S3 case also demonstrates reduced combustion efficiency, with CO emissions rising by 156.4% relative to S2. Local flame extinction is observed in regions of strong droplet–flame interaction, highlighting enhanced quenching susceptibility under near-blow-off conditions. The present study investigates the flame dynamics in a multi-stage swirl combustor using high-fidelity CFD simulations. This study has yet to be validated through experimental analysis and the results presented in this work are entirely computational. Further experimental validation is necessary to verify the results. Full article

The development of anisotropic gold nanostructures supporting localized surface plasmon (LSP) resonances in the near-infrared (NIR) biological window is of great interest for diagnostic and therapeutic nanotechnologies. Here, we report gold open-shell nanoparticles (AuOSNs), a symmetry-broken nanoshell architecture exhibiting strong NIR surface-enhanced Raman scattering (SERS) activity. AuOSNs were fabricated via a surfactant-free strategy combining bottom-up silica sphere assembly with a simple top-down gold deposition process, without using highly cytotoxic surfactants such as cetyltrimethylammonium bromide (CTAB). Boundary element method (BEM) simulations revealed that the asymmetric open-shell geometry induces NIR LSP resonances with pronounced electromagnetic field localization near the opening edges, depending on excitation configuration. Consistent with these predictions, extinction spectra of AuOSNs dispersed in water showed an LSP resonance peak at ~793 nm, close to the 785 nm excitation wavelength for SERS. In aqueous dispersion, AuOSNs modified with 4-mercaptobenzoic acid (4-MBA) exhibited strong SERS activity with enhancement factors of ~10⁶. Furthermore, polyethylene glycol (PEG)-modified MBA/AuOSNs showed negligible cytotoxicity in vitro. SERS imaging confirmed that PEG/MBA/AuOSNs enable visualization of HeLa cells via characteristic MBA SERS signals. These results demonstrate that surfactant-free AuOSNs provide a biocompatible platform for NIR-excited SERS sensing and cellular imaging, highlighting their potential in plasmonic bioimaging applications. Full article

Climate-smart forestry (CSF) is a comprehensive approach that aims to sustainably enhance wood productivity (production), improve forest resilience and adaptation, sequester carbon (mitigation), and support broader development goals. This strategy is profoundly linked with Forest Genetic Resources (FGR), which are crucial for the adaptive capacity and long-term sustainability of forest ecosystems in the face of the escalating climatic changes. Climate change presents significant risks, including increased air temperatures, altered precipitation regimes, and a rise in extreme weather events, leading to tree mortality, shifts in vegetation distribution, and a potential loss of critical forest functions and services, such as carbon sequestration capacity. While forests have inherent resilience, the rapidity and magnitude of projected changes may exceed their natural adaptive capacity, potentially resulting in local extinction and degradation of ecosystems. This review explores various facets of the interplay between CSF and FGR, emphasizing their role in sustainable forest management. Key areas of focus include: (1) Genetic Diversity, (2) Genotype Selection and Breeding, (3) Modern Breeding Techniques, (4) Molecular Breeding, (5) Genomic Prediction (GP), (6) Breeding Programs, (7) Silvicultural Practices, (8) Adaptation Mechanisms, (9) Phenotypic Plasticity, (10) Migration, particularly Assisted Gene Flow (AGF) and (11) Reproductive Material Management. Ultimately, the study highlights the crucial role of FGR in the resilience of forest ecosystems and proposes future actions for their integration into CSF strategies, including in situ and ex situ conservation, assisted migration, advanced research and development, community involvement, and supportive policy frameworks, all vital for the long-term sustainability and vitality of forest ecosystems in a changing climate. Full article