Search Results (10,036)

The valorization of agricultural and other waste residues into biochar represents a promising strategy for sustainable waste management and environmental remediation within a circular economy framework. Engineering multifunctional biochars like agricultural waste-derived biochars (AWDBs) exhibit tunable physicochemical properties governed by feedstock characteristics and thermochemical conversion conditions, enabling their application across water, soil, and sediment systems. While extensive research has demonstrated the effectiveness of biochar in isolated environmental compartments, natural systems function as interconnected water–soil–sediment continua, where pollutants, nutrients, and organic matter dynamically interact. This review critically synthesizes recent advances in the production, properties, and environmental applications of biochars, with a particular focus on their multifunctional performance in coupled environmental systems. Mechanistic insights into contaminant sequestration, nutrient cycling, and microbial interactions across media are discussed, alongside evidence of synergistic and antagonistic effects arising from cross-media processes. Despite significant progress, major knowledge gaps persist, including limited integrated multi-medium studies, lack of standardized assessment methodologies, insufficient understanding of long-term biochar stability, and challenges associated with field-scale implementation. Future research directions are proposed to address these limitations through standardized protocols, engineered multifunctional biochars, long-term monitoring, and policy integration. Advancing a system-based perspective is essential to unlock the full potential of agricultural waste-derived biochars for sustainable and scalable environmental remediation. Full article

This study presents a theoretical analysis of the slow translation of a soft sphere through an unbounded micropolar fluid under steady, low Reynolds number conditions, accounting for the influence of interfacial stress jump. The soft sphere is modeled as a rigid solid core surrounded by a permeable porous gel layer, allowing fluid penetration and momentum exchange across the interface. This core–shell configuration captures the essential structural characteristics of coated or gel-like particles encountered in biological and engineering systems. Closed-form expressions for the velocity components, microrotation, stresses, and couple stresses are derived both within the porous micropolar gel layer surrounding the particle and in the exterior micropolar fluid. The flow inside the permeable coating is described using the general Brinkman solution in spherical coordinates, while the governing micropolar fluid equations are applied in the outer region. Appropriate boundary conditions are imposed at the solid core surface and at the permeable soft-sphere interface to ensure continuity of velocity and microrotation, together with the prescribed stress jump. The normalized drag force acting on the particle is obtained as a function of the particle-to-core radius ratio, permeability, stress-jump parameter, and micropolarity parameter. The results indicate that the hydrodynamic drag decreases as the porous layer becomes thicker and remains finite, approaching unity even when the soft sphere behaves as a solid particle or as a porous sphere translating through an infinite micropolar medium, with other parameters held fixed. Overall, the analysis elucidates the coupled roles of micropolar effects, interfacial stress jump, and porous-layer structure in governing the hydrodynamic resistance experienced by soft particles. . Full article

This study examines how sustainability orientation shapes sustainability behavior among entrepreneurial small and medium-sized enterprises (SMEs) in Turkey. Grounded in self-determination theory (SDT) and the theory of planned behavior (TPB), this study develops and empirically tests a conditional process model in which perceived social support functions as a mediating mechanism and sustainable entrepreneurship operates as a boundary condition. Data were collected from 519 senior managers of ISO 14001-certified SMEs using a two-wave survey design to mitigate common method variance (CMV). Using Hayes’ PROCESS macro, the results indicate that sustainability orientation is positively associated with sustainability behavior and that perceived social support partially mediates this relationship by facilitating the translation of sustainability values into action. Furthermore, sustainable entrepreneurship strengthens both the direct association between sustainability orientation and sustainability behavior and the indirect pathway operating through perceived social support. SMEs with higher sustainable entrepreneurship capabilities are better positioned to leverage internal values and external social reinforcement to enact proactive sustainability practices. Overall, the findings highlight the joint role of motivational orientations, social reinforcement, and entrepreneurial capability in shaping sustainability outcomes. The study contributes to sustainability and entrepreneurship research by clarifying how value-based orientations are converted into sustainable behavior and offers practical implications for policymakers and SME leaders seeking to accelerate sustainability transitions in emerging economies. Full article

To investigate the influence of a second-phase mineral on the rheology of mantle peridotite, we conducted high-temperature deformation experiments on dry olivine–clinopyroxene (Ol-Cpx) aggregates. Cylindrical samples were manufactured using hot-isostatic pressing techniques, with Ol as the matrix phase and Cpx added at volume fractions of f_Cpx = 0.1, 0.3, and 0.5. Deformation experiments were performed in a Paterson gas-medium apparatus at a confining pressure of ~300 MPa, temperatures ranging from 1423 to 1523 K, and strain rates of ~5 × 10⁻⁶ s⁻¹, ~1 × 10⁻⁵ s⁻¹, ~2 × 10⁻⁵ s⁻¹, and ~5 × 10⁻⁵ s⁻¹. The stress exponents (n = 3.4–4.3) for two-phase aggregates are comparable to those reported for both pure Ol and pure Cpx, indicating that dislocation creep remains the dominant deformation mechanism. Increasing Cpx content does not induce a transition of dominant mechanism but leads to a slight decrease in activation energy, consistent with predictions from two-phase rheological models and reflecting the increasing contribution of Cpx to bulk deformation. Normalized flow stresses fall between the Ol and Cpx end-members within the Taylor–Sachs bounds, indicating moderate strain partitioning between phases. Aggregates with f_Cpx = 0.5 show slightly reduced strength and lower effective stress exponents. This is attributed to enhanced dynamic recrystallization, which triggers grain-size reduction and thereby increases the contribution of diffusion-assisted deformation, even though dislocation creep remains the dominant mechanism. These results suggest that under dry conditions, Cpx primarily modulates the rheology of olivine-rich aggregates through microstructural evolution and strain partitioning rather than by altering the dominant deformation mechanism. Full article

Coffea canephora is economically and socially important for small-scale agriculture in Northern Brazil. To identify genotypes adapted to Amazonian edaphoclimatic conditions, clones of the species have been evaluated across multiple locations in Amazonas. Introducing genetically selected materials into comparable environments may promote consistent productivity gains in the short and medium term. In this context, the aim of this study was to assess the genetic diversity of different C. canephora genotypes using microsatellite markers, which will support the development of superior genotypes adapted to Amazon conditions. A total of 43 C. canephora genotypes were analyzed. Leaves were collected for genomic DNA extraction and were standardized and amplified by PCR using microsatellite primers. Genotyping was performed via capillary electrophoresis, allowing for the determination of allele sizes. Genetic structure was inferred, and genetic diversity parameters were estimated. The average observed heterozygosity (H_O = 0.64) exceeded the expected heterozygosity (H_E = 0.53), and the average inbreeding coefficient (f = −0.19) indicated an excess of heterozygotes. The results revealed high genetic variability among the evaluated genotypes. These findings highlight the broad genetic diversity of C. canephora, reinforcing its potential as a genetic basis for selection and the development of cultivars adapted to the environmental conditions of the Amazon. Full article

Background: Extraintestinal pathogenic Escherichia coli (ExPEC) poses significant health risks to poultry and humans, with biofilm formation often complicating treatment by enhancing bacterial persistence and resistance. Understanding the genetic mechanisms underlying this lifestyle transition is crucial for controlling infections. This study aimed to investigate the effect of biofilm formation on the transcriptional expression of specific biofilm- and virulence-associated genes in chicken-derived ExPEC strains. Methods: Biofilm formation conditions for three strong biofilm-producing chicken-derived ExPEC strains were optimized using an orthogonal experimental design (L₉(3³)), evaluating culture medium, incubation time, and initial inoculum concentration. Biofilm biomass was quantified via crystal violet staining. Subsequently, the transcription levels of 10 biofilm-associated genes and 17 virulence-associated genes were compared between planktonic and biofilm states using Reverse Transcription-quantitative PCR (RT-qPCR). Results: Optimal culture conditions varied among strains, though nutrient-rich media consistently promoted rapid biofilm formation. Transcriptional analysis revealed significant reprogramming in the biofilm state. Among biofilm-associated genes, flhC, tolA, qseC, mhpB, and bdcR were consistently and significantly upregulated across all strains (p < 0.05). Regarding virulence determinants, the expression of eaeA, LT, fimH, ompF, and iss was significantly upregulated (p < 0.05), whereas Sta levels were significantly reduced (p < 0.05). Conclusions: Biofilm formation induces a distinct transcriptional shift in chicken-derived ExPEC, simultaneously enhancing the expression of key genes involved in biofilm maintenance and pathogenicity. The conserved upregulation of flhC, tolA, qseC, mhpB, and bdcR suggests these genes are critical drivers of biofilm development. Consequently, they represent potential targets for novel therapeutic strategies aimed at preventing E. coli infections and eradicating biofilms in clinical and agricultural settings. Full article

This study examines how digital transformation (DX) unfolds in Small and Medium-sized Enterprises (SMEs) through an analytical integration of dynamic capabilities (DCs) and service-dominant logic (SDL). While DX research is abundant, existing studies tend to discuss internal organizational capabilities (DCs) and external value co-creation (SDL) in isolation, offering limited insight into how resource-constrained SMEs execute transformation in practice. Employing a multiple case study approach based on Japanese SMEs, this paper uses the micro-foundations of DC (sensing, seizing, and transforming) as an analytical lens to examine how the resource integration processes emphasized in SDL are operationalized through phased organizational decision-making. The findings illustrate that while DC provides the organizational process logic for change, SDL offers the perspective through which SMEs overcome internal resource scarcity by engaging in external collaboration. By bridging internal capability-based and external co-creation perspectives, this study contributes to a more granular and contextually grounded understanding of transformation processes under resource constraints. From a practical perspective, the findings highlight the importance of fostering dialogue and building external relationships as conditions for activating dynamic capabilities and mitigating organizational rigidity, offering practically relevant implications for SME managers and policymakers. Full article

Background: Democratic participation depends on three foundational social mechanisms: communication, interpersonal relationships, and socialization. While these mechanisms are well-understood in physical civic settings, their operation in digital environments remains unclear. For the purposes of this review, “fragility” is defined as a structural property of participatory systems, referring primarily to the conditional and variable alignment of these three mechanisms—an alignment that physical environments tend to support by default but that digital environments reproduce only under specific conditions. Methods: This study conducted a targeted high-impact review of twenty-two highly cited Scopus publications (2004–2025) to assess whether communication, interpersonal relationships, and socialization continue to function as core, but not individually sufficient, conditions for democratic engagement online. The review synthesizes findings across three research questions examining each mechanism, using narrative thematic analysis to identify dominant patterns within citation-established scholarship. Results: Across the reviewed corpus, participation strengthens when communication is informationally rich and heterogeneous, when relationships foster trust and bridging social capital, and when socialization environments support civic learning and identity formation. Weak informational content, homogeneous networks, and reduced socialization produce thinner or unstable democratic outcomes. The findings reveal that the three mechanisms operate interdependently: their democratic effects depend on simultaneous alignment rather than individual presence. Conclusions: Digital environments can support meaningful participation only when platform architecture reinforces these core social mechanisms. Strengthening informational diversity, relational openness, and digital socialization is essential for robust platform-mediated democratic engagement. Synthesizing these findings, the study proposes a Conditional Model of Digital Democratic Participation, which argues that digital fragility arises not from the medium itself but when the qualitative conditions required to validate the core social mechanisms fail to align. The Conditional Model differs from existing frameworks by treating communication, relationships, and socialization as interdependent mechanisms whose democratic effects are conditional on their simultaneous presence. Digital participation is not weak—it is conditional. Full article

An injury to the elbow’s lateral ulnar collateral ligament (LUCL) is an orthopedic emergency that can impair joint stability and functional biomechanics throughout the upper extremity. The development and application of synthetic ligament substitutes, particularly short-chain-length and medium-chain-length polyhydroxyalkanoate (SCL-PHA and MCL-PHA) co-polymers, represent a promising innovation for lateral elbow stabilization. This experimental cadaveric study aimed to (1) compare biomechanical parameters of torque and angular rotation among control, damage, repair, and reconstruction groups and (2) compare stress and strain responses across the same groups. Twenty-four cadaveric elbows were allocated among six experimental conditions. The control group consisted of intact elbows (n = 4), while the damage group (n = 4) involved transection of the anterior capsule and extensor carpi radialis brevis (ECRB) to simulate ligament injury. The repair group (n = 4) underwent anterior capsular suturing. The reconstruction group (n = 12) was divided into three subgroups: palmaris longus (PL) autograft alone, PL with SCL-PHA co-polymer augmentation, and PL with MCL-PHA augmentation. Biomechanical testing measured maximum torque, angular displacement, shear stress, and strain, with statistical analysis conducted using descriptive statistics, one-way ANOVA, and post hoc multiple comparisons. The results demonstrated that maximum torque (F = 24.930, p < 0.001) and maximum shear stress (F = 8.130, p < 0.001) significantly differed among groups. The control group exhibited the highest mechanical performance (30.700 ± 9.368 Nm and 0.880 ± 0.216 MPa), whereas the damage group showed the lowest values (10.300 ± 2.904 Nm and 0.210 ± 0.073 MPa). The reconstruction group using palmaris longus with SCL-PHA co-polymer reinforcement (RC-PLSCL) demonstrated torque (29.550 ± 7.656 Nm) and shear stress (0.610 ± 0.206 MPa) comparable to those of the control group (p > 0.05), indicating near-physiological mechanical behavior. These findings suggest that SCL-PHA co-polymer augmentation offers superior biomechanical restoration relative to standard repair and other reconstruction strategies, highlighting its potential as an advanced biomaterial for ligament reconstruction in LUCL injuries. Full article

Since their recognition as human pathogens in the 1970s, Campylobacter spp. have posed persistent challenges to microbiologists due to their fastidious growth requirements and environmental sensitivity. The continuous refinement of selective and differential culture media has been crucial for improving their detection, isolation, and characterization in both clinical and food microbiology. This comprehensive review provides a chronological overview of the evolution of Campylobacter culture media, highlighting the scientific milestones that shaped current cultivation practices—from early blood- and charcoal-based formulations to modern selective, chromogenic, and systems permitting incubation under less stringent atmospheric conditions. Emphasis is placed on the rationale behind medium composition, the transition from empirical experimentation to standardized formulations, and the integration of molecular and metabolic insights into media design. The evolution of Campylobacter growth media mirrors the broader trajectory of microbiology itself, moving from artisanal experimentation toward precision-driven innovation. Ongoing advancements in culture technology, including sustainable and data-guided formulations, will continue to enhance global surveillance, food safety, and pathogen ecology research. Full article

Central European children’s literature can be read as both archive—recording shifting norms, institutions, and visual regimes—and agent, a medium through which childhood, citizenship, and cultural memory are made legible. This conceptual article proposes an edition-sensitive framework for analysing texts, images, and paratexts across Central Europe (1860–2025), with particular attention to institutional mediation. Rather than offering a comprehensive dataset or causal claims about reception, it synthesises research in childhood history, book and media history, memory studies, and translation and circulation studies to advance three arguments. First, children’s books are institutionally framed artefacts: paratexts and material features (series branding, curricular endorsements, library markings, pricing cues, regulatory traces) can be read as historically interpretable speech acts of legitimation. Second, shifts in visual and material regimes should be analysed as changing conditions of legibility—expectations of clarity, affect, and authority—rather than as mere stylistic evolution. Third, translation and circulation function as infrastructures that reorganise repertoires and interpretive horizons, complicating nation-centred narratives without exhaustive market mapping. The article concludes by stating methodological limits (catalogue gaps, survival bias, uneven metadata) and outlining a transferable agenda for paratext-centred documentation and edition-sensitive reading. Full article

Addressing the technical bottlenecks of excessive surface density in traditional magnetic metal powder absorbers and excessive thickness in conventional foam-based absorbers, this study proposes a novel lightweight, ultra-wideband microwave-absorbing metamaterial. This metamaterial, through multi-layer and multi-dimensional structural design, has constructed a composite structure composed of a resistive film frequency-selective surface, a foam wave-absorbing medium layer and a reflective layer, achieving the controllable regulation of microwave absorption performance and the integration of structure and function. The research results show that the fabricated absorbing metamaterial achieves efficient electromagnetic wave absorption over a wide frequency band of 94 GHz under the ultra-light and ultra-thin conditions with a density as low as 0.078 g/cm³ and a thickness of only 4.9 mm. This study provides an effective design concept and solution for developing new lightweight, thin-layer, wide-band, and highly microwave-absorbing materials. Full article

Biodegradable polymers based on poly(lactic acid) (PLA) and polyhydroxybutyrate (PHB) are widely investigated for biomedical engineering applications, particularly for temporary implants and tissue scaffolds fabricated by additive manufacturing. However, their degradation behavior is influenced not only by material composition, but also by manufacturing-related parameters, geometric design, and environmental conditions. This study investigates the in vitro degradation behavior of PLA/PHB structures fabricated using fused filament fabrication (FFF). Degradation was evaluated under two model environmental conditions over a 45 day period. Changes in specimen mass and the evolution of degradation medium pH were monitored as a function of exposure time, specimen geometry, and infill density. The results revealed a progressive degradation process, with pH values decreasing to approximately 2.7–4.1 in physiological saline solution and increasing to 8.9–9.7 in urea solution, depending on specimen geometry and infill density. After 45 days of exposure, the relative mass loss reached approximately 25–32% for type A specimens and 29–41% for type B specimens. The results revealed distinct differences between degradation environments and specimen geometries, while differences related to infill density partially overlapped within the investigated range. The findings indicate that the degradation behavior of additively manufactured PLA/PHB structures cannot be interpreted solely based on material composition, but should be considered in the context of manufacturing strategy and structural design. These results provide useful insights for the design of biodegradable polymer components with more predictable degradation behavior. Full article

Accurate estimation of building-specific air change rates is important for reliable urban-scale energy modeling, particularly in densely populated regions where airflow calculations must account for complex boundary conditions associated with urban geometry. This study applied lumped-parameter airflow models to simulate interzone airflow by calculating the internal pressures using simplified building representations. Air change rates were calculated by solving a system of nonlinear equations, with boundary conditions defined by localized wind inputs corrected using aerodynamic parameters extracted from three-dimensional urban geometry. By linking these wind-related boundary conditions with lumped-parameter airflow models, the methodology describes spatial variability in natural infiltration across a broad range of urban densities. Two cities were compared to test the variability in building air change rates using local boundary conditions: New York City, a dense modern city, and Turin, a typical medium-density European city. Moreover, verifying the lumped-parameter model against CONTAM (Version 3.4.0.6) showed accurate results, with a mean absolute percentage error of 1.2% across 120 simulated weather scenarios. Furthermore, comparing energy consumption predictions using building-specific air change rates to those using fixed air change rates showed improved accuracy, resulting in an average error reduction of 27% over the entire heating season for a sample building. This scalable, automated approach enables more accurate assessments of ventilation-driven energy use in compact urban areas. Full article

High-temperature self-lubricating materials with stable tribological performance across a wide temperature range are essential for advanced mechanical systems under extreme conditions. However, balancing mechanical strength and lubrication efficiency remains a key challenge. This study fabricated CoCrFeNiMox-Ni/MoS₂-Ag-Cr₂O₃ composites (x = 0.2, 0.5, 1) via spark plasma sintering, aiming to investigate the effect of Mo content on their microstructure, mechanical properties, and tribological behavior. Microstructural analysis showed that the as-sintered composites mainly consist of FCC phase, Cr₂O₃, Ag, and Ni/MoS₂. Increasing Mo content from 0.2 to 1 wt.% significantly promoted the formation of hard σ-phase intermetallics, leading to increased hardness (up to 546 HV) and yield strength (peaking at 502 MPa). Tribological tests at 25–800 °C indicated continuous lubrication behavior in all composites. The minimum friction coefficient was 0.23, and wear rates remained below 10⁻⁶ mm³/N·m. In the low-to-medium temperature range, lubrication was dominated by the synergistic effect of Ni/MoS₂ and Ag: Ni/MoS₂ formed low-shear-strength films, while Ag reduced surface adhesion. Meanwhile, the Mo solid solution strengthened and the σ-phase enhanced wear resistance by improving hardness and inhibiting plastic deformation. At high temperatures, tribochemical reactions generated lubricating films composed of oxides and molybdates, which maintained tribological performance by reducing direct contact between friction pairs. This study demonstrates that Mo-doped high-entropy alloy composites can serve as high-performance wide-temperature self-lubricating materials, providing a basis for designing “matrix-lubricant” systems for extreme-temperature applications. Full article