Found 369 results
Open Access
Article
29 December 2025Vertical Axis Tidal Turbine Behaviour under Sheared Flow Effects
Tidal turbines are often subjected to complex flow conditions that can affect their power output and the risk of failure. In this article, an experimental study on a vertical axis tidal turbine with twin counter-rotating rotors is carried out at 1/20 scale, submitted to a sheared turbulent (ST) flow and a sheared weakly turbulent (SWT) flow. The performance and wake development comparison indicates that the turbine behaves differently depending on the shear rate considered. A 7% decrease in performance is observed at the turbine’s nominal operating point between uniform and ST conditions. The asymmetry of the flow along the vertical axis is reflected in the angular and frequency distributions of the rotor torque, indicating a production asymmetry between the lower and the upper rotors. Analysis of wake development reveals that transport terms constitute the main mechanism of wake dissipation. In the case of SWT and uniform flow, vertical advection largely dominates the other terms, whereas in ST flow, transverse advection is initially predominant. This results in a higher average wake height and a lower average wake width in the ST case compared to the other flow conditions, and a faster wake recovery.
Open Access
Article
26 December 2025Leveraging Productivity Analysis for Smallholders’ Sustainable Development: Dairy Efficiency in Central Madagascar’s Crop-Livestock Family Farms
Milk production in developing African countries is a viable path for smallholders’ sustainable development. Supporting interventions should be shaped by evidence from comprehensive, context-specific analyses. Using survey data, this study contributes to the development-oriented literature on dairy productivity in African smallholder systems by conducting the first stochastic frontier analysis in the Malagasy context. Focusing on milk producers in central Madagascar’s crop-livestock family farms, a stochastic frontier production function with inefficiency effects is developed. The fitted frontier comprises the number of cows, annual purchased feed expenditure, farmer’s labor, and total household assets owned. Distance from the frontier is explained by the use of improved breeds, integration in the regional milk zone, farmer years of experience, the presence of off-farm income, and the number of oxen owned. Technical efficiency ranged from 4.6% to 90.8% around a mean of 55.5%. Results revealed how, in this context, cows are embedded in diversified family farming systems where resources are allocated across production activities and household needs. The study’s multidisciplinary stochastic frontier analysis provides a more complete picture to guide research and policy for smallholders’ sustainable rural development.
Open Access
Communication
26 December 2025Extracellular Vesicles from Oral Squamous Cell Carcinoma Carry OGT/OGA with Possible Implications in Tumor O-GlcNAcylation
Oral squamous cell carcinoma (OSCC) is a malignant epithelial neoplasm characterized by high aggressiveness and limited options for early diagnosis. In recent years, extracellular vesicles (EVs) have gained attention as mediators of intercellular communication in cancer, contributing to tumor progression and remodeling of the microenvironment. O-GlcNAcylation, regulated by O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA), participates in multiple tumor processes; however, its association with EVs in OSCC has not yet been explored. In this study, EVs were isolated from SCC-152, SCC-25, and HaCaT cell lines using differential centrifugation, and their identity was confirmed by detection of CD63 and TSG101 markers and by transmission electron microscopy (TEM). Immunocytochemistry revealed the nuclear and cytoplasmic localization of OGT and OGA in all analyzed cell lines. Importantly, both enzymes were detected in EVs cargo by Western blot analysis, with significant differences between tumor and non-tumor lines as determined by densitometric and fluorescence intensity analyses. Quantitative analysis indicated a higher relative signal for OGA compared with OGT across all cell lines (with an approximate ~1.5–2.2-fold difference depending on the cell line, p < 0.05), and cell line-derived samples showed a higher relative signal than non-tumoral HaCaT (corresponding to an approximate ~1.2–1.3-fold increase under the experimental conditions evaluated). All experiments were performed using three independent biological replicates (n = 3), and statistical significance was assessed using one-way or two-way ANOVA followed by Tukey’s post hoc test. These findings suggest that OSCC-derived EVs carry enzymatic components of the O-GlcNAcylation machinery as vesicular protein cargo, potentially influencing tumor microenvironment regulation and cancer progression. Overall, these results should be considered hypothesis-generating, opening new perspectives for their use as vesicular biomarkers.
Open Access
Perspective
24 December 2025Revisiting the Conservation Challenges of Wild Argali (Ovis ammon ammon L.) in the Altai Mountain-Steppe under Climate and Anthropogenic Pressures
The high-mountain steppes of South-eastern Altai are a valuable resource for pastoralism—almost the only possible type of economic activity in these places—and the conservation of near threatened species, such as the argali. Argali are the largest and most vulnerable wild sheep (Ovis ammon ammon L.), and are listed in the Red Data Book of the Russian Federation and on the IUCN Red List. The argali is also important in the food chain of another rare and protected species, the snow leopard. This paper presents the results of research into the productivity of argali’s high-mountain steppes habitation in various parts of the Sailugem Ridge, and assesses their pasture degradation. We predict how observed declining pasture productivity due to anthropogenic and climate pressure, as well as argali grazing, will threaten their survival. We propose special measures to reduce the impact of the argali population on the degradation of current pastures, while improving argali conservation in other areas of South-eastern Altai and adjacent territories where the species previously existed.
Open Access
Review
23 December 2025A Review of Bolted Connections for the Assembly of Floating Offshore Wind Turbine Foundations
Bolted connections are being considered as an assembly method for the foundations of floating offshore wind turbines. A clear benefit of this method is the short assembly time of these foundations compared to welding. However, some concerns around corrosion, fatigue, and the ability of bolted connections to maintain preload remain. This review found that conventional ring flanges may not be suitable for the assembly of floating foundations, mainly due to the risk of bolt loosening and reduced fatigue life. However, the C1 Wedge Connection is an innovative bolted connection that has shown its ability to retain bolt preload during tests. Likewise, the Compact Flange Connection has shown its ability to retain preload without requiring maintenance during operational stages and furthermore, has a long and successful track record in offshore oil and gas applications. This review revealed several research gaps related to the use of bolted connections for the assembly of floating wind turbine foundations. These include: a lack of research on the effects of bolt loosening; dynamic loads and shear forces on bolted connections and their effect on fatigue life; structural health monitoring methods of bolted connections; and the health and safety of technicians in confined spaces with difficult accessibility. The Compact Flange Connection is perhaps the best suited bolted connection for the assembly of floating foundations. However, more research, and crucially, successful offshore demonstrations will be essential to increase confidence in the suitability of bolted connections for the floating offshore wind industry.
Open Access
Article
23 December 2025Wave Effects on Large-Scale Turbulent Flow Structures Propagating in the Water Column
Tidal flow often contains large-scale turbulent flow structures mainly caused by bathymetric variations or offshore marine structures. Understanding how waves interact with these structures is crucial for ocean sciences, as they influence vertical mixing, energy transfer, and dissipation. In this work, two flow configurations with current and waves are studied in a flume tank using Particle Image Velocimetry measurements: waves propagate either following or opposing the current and interact with convected flow structures. Compared to current-only cases, the mean velocity is slightly impacted, but the mean velocity gradient increases for waves propagating with the current. Turbulent Kinetic Energy increases regardless of wave direction and its production is also affected by the wave’s propagation direction. The integral length scale and flow Gaussianity are the most affected flow parameters. For waves propagating against the current, the Probability Density Functions of fluctuating velocity fields exhibit a bimodal representation, largely deviating from a Gaussian curve. Preliminary quadrant analysis reveals that waves significantly influence flow organisation, especially when they propagate against the current. These observations are valuable for applications such as defining tidal turbine farm areas, improving turbine performance estimation, and assessing structural fatigue.
Open Access
Communication
19 December 2025Visualization of Latent Fingermark on Metallic Surfaces Based on Displacement Reactions
Fingermarks are frequently left on metal surfaces such as kitchen utensils, door handles, or elevator buttons in crime scenes. They are crucial forensic evidence to identify individuals and link them to crimes. Fingermark development on metal surfaces targets either the fingermark residues or the substrate. This study aimed to develop a rapid fingermark development method based on displacement reactions between copper (II) sulphate and various types of metal substrates, such as brass, galvanized iron, and low-carbon steel. Immersion of the metal substrate was more effective in fingermark visualization than applying the solution using a dropper. The optimized concentrations of copper (II) sulphate solution for fingermark visualization were found to be 0.7 M for brass, 0.5 M for galvanized iron, and 0.2 M for low-carbon steel. Sebaceous-rich fingermarks were visualized after the 5th depletion on brass and galvanized iron, and even after the 7th depletion on low-carbon steel. Further improvement is required before incorporating the application of copper (II) sulphate onto metal substrates to visualize fingermarks in real crime cases, due to the destructive nature of substrate submersion.
Open Access
Review
19 December 2025Contemporary Multimodality Imaging Evaluation in Native Aortic Stenosis
Aortic stenosis (AS) is the most prevalent valvular heart disease in developed nations, with increasing incidence driven by population aging. Early and accurate diagnosis is crucial, as timely intervention significantly improves outcomes. Contemporary imaging plays a central role in the assessment of AS, enabling precise evaluation of valve anatomy, disease severity, left ventricular remodeling, and procedural planning. Transthoracic echocardiography remains the first-line modality, providing essential hemodynamic and structural data. However, limitations in cases of low-flow states, discordant grading, and atypical presentations necessitate adjunctive tools. Transesophageal echocardiography enhances visualization of valve morphology and annular dimensions, particularly for pre-procedural assessment. Cardiac computed tomography (CT) has emerged as a cornerstone in transcatheter aortic valve replacement (TAVR) planning, offering unparalleled spatial resolution for annular sizing, coronary height measurement, and vascular access evaluation. Meanwhile, cardiac magnetic resonance (CMR) provides robust quantification of ventricular volumes, fibrosis, and myocardial strain, serving as a prognostic marker in asymptomatic and borderline cases. The integration of multimodality imaging offers a comprehensive framework, addressing diagnostic ambiguities and guiding individualized management strategies. This review highlights current advances, clinical applications, and future directions in multimodality imaging for AS, emphasizing its pivotal role in optimizing patient selection, risk stratification, and procedural outcomes.
Open Access
Article
16 December 2025Toluene or Formaldehyde Removal by Photocatalysis and Adsorption Using Hybrid Optical Fiber Textiles Containing Activated Carbon and/or TiO2
Indoor air treatment has become a significant concern in recent years. The aim of this study is to investigate the effectiveness of coupling adsorption and photocatalysis for the removal of toluene and formaldehyde, especially in the presence of optical fiber textile. First, we examine the adsorption properties of various commercial activated carbon (AC) filters, as well as different amounts of AC deposited on optical fiber textiles, and assess the impact of titanium dioxide (TiO2) on the adsorption performance. In the second phase, we compare the photocatalytic degradation of toluene and formaldehyde under different irradiance levels. Finally, we analyze the impact of three AC-TiO2 combinations: separate filters, TiO2 deposited on AC-impregnated fiber optic textiles, and TiO2 partially deposited on AC filters. The results led us to test a new photocatalytic and adsorbent material, including heating wires and optical fibers.
Open Access
Article
16 December 2025Design and Implementation of an Autonomous Smart Food Delivery Robot for Commercial Environments
The integration of robotics into service environments is transforming how labor-intensive tasks are managed, particularly during peak hours with staff shortages and long wait times. This research presents a fully autonomous, modular food-delivery robot designed to enhance operational efficiency and improve service experience. The system combines artificial intelligence, facial recognition, smartphone-based order management, Arduino, ESP32, ESP32-CAM, and Python to navigate indoor environments and deliver food directly to recipients, supported by a secure handover mechanism. Experimental results indicate that the robot performs waiter-like delivery reliably, maintaining mobility and structural integrity across various surfaces by using lightweight materials and motors that have been optimized. Through the use of a motion coordination algorithm, responsive navigation can be achieved, while a simple user interface can be operated by anyone with minimal training. According to these results, automation reduces the need for manual labor, increases the speed of service, and ensures consistency in the delivery process. Additionally, the system provides a practical framework for future research and potential applications beyond food delivery, such as surveillance, environmental monitoring, and disaster response. Future work will focus on scaling for real-world deployment and integration advanced AI navigation to enhance autonomy, adaptability, and overall operational performance.
