Search Results (49)

The aim of the work is to analyze the survival strategy of Taxus baccata L., one of the promising plants for landscaping and the creation of woodlands, in the changing ecological conditions of the steppe zone of the Donetsk ridge. In order to achieve this goal, we used biomechanics methods, which help to understand the relationship between the physical and mechanical properties of living tissues and the overall stability of trees during interactions with environmental factors such as temperature, snow and ice storms, cyclic freeze–thaw processes, wind loads, and others. The work was based both on experimental studies on the estimation of the tissue elasticity modulus in response to temperature changes, the mechanical stability of plants, the field collection of materials, and studies on the modeling of forest stand conditions of English yew. As a result of the conducted experiments, it was established for the first time that at the absolute wood moisture content of 77 ± 5.1%, the density of wood tissues in the conditions of Donetsk is 907 ± 43 kg m⁻³. The modulus of elasticity of living tissues depending on the temperature factor varied in the following range: 8.8 ± 0.31 GN m⁻² (T = 288 K), 11.5 ± 0.55 GN m⁻² (T = 255 K) and 6.9 ± 0.47 GN m⁻² (t = 308 K). It was revealed that during the local thawing of skeletal branches and tables, the mechanical resistance of T. baccata is reduced by 20–22% and this critically affects the overall plant resistance. It was established for the first time that T. baccata in the conditions of the steppe zone has an adaptive strategy of preserving the integrity of the organism under the action of environmental factors with limited loads. The secret lies in the formation of the shape memory effect, under the influence of critical loads. The plant, thus, chooses not migration, not death, but adaptation to changes in environmental conditions, which can become a serious factor in the use of T. baccata in the landscaping of urban areas and the creation of artificial forests. Full article

During icebreaker navigation in ice-covered waters, icebreaking resistance and dynamic ice loads acting on the bow critically determine the vessel’s icebreaking performance. Quantitative characterization of the icebreaking resistance behavior and ice load distribution on the bow is essential for elucidating ship-ice interaction mechanisms, assessing icebreaking capability, and optimizing structural design. This study conducted comparative icebreaking tests on two icebreaker bow models with distinct geometries in the small ice model basin of China Ship Scientific Research Center (CSSRC SIMB). Systematic measurements were performed to quantify icebreaking resistance, capture spatiotemporal ice load distributions, and document ice failure patterns under level ice conditions. The analysis reveals that bow geometry profoundly influences icebreaking efficiency: the stem angle governs the proportion of bending failure during vertical ice penetration, while the flare angle modulates circumferential failure modes along the hull-ice interface. Notably, the sunken keel configuration enhances ice clearance by mechanically expelling fractured ice blocks. Ice load distributions exhibit pronounced nonlinearity, with localized pressure concentrations and stochastic load center migration driven by ice fracture dynamics. Furthermore, icebreaking patterns—such as fractured ice dimensions and kinematic behavior during ship-ice interaction—are quantitatively correlated with the bow designs. These experimentally validated findings provide critical insights into ice-structure interaction physics, offering an empirical foundation for performance prediction and bow-form optimization in the preliminary design of icebreakers. Full article

The high cost of platinum (Pt) catalysts impedes the widespread commercialization of proton exchange membrane fuel cells (PEMFCs). Reducing Pt loading will increase local oxygen transport resistance ($R_{\mathrm{Pt}}^{{\mathrm{O}}_2}$) and decrease performance. Due to the oxygen transport resistance, the reactants in the cathode catalyst layer (CCL) are not evenly distributed. The gradient structure can cooperate with the unevenly distributed reactants in CL to enhance the Pt utilization. In this work, a one-dimensional gradient CCL model considering $R_{\mathrm{Pt}}^{{\mathrm{O}}_2}$ is established, and the optimal gradient structure is optimized by combining the artificial neural network (ANN) model and the genetic algorithm (GA). The optimal structure parameters of non-gradient CCL are l_CL equal to 8.86 μm, r_C equal to 36.82 nm, and I/C equal to 0.48, with the objective of maximum current density (I_max); l_CL equal to 4.24 μm, r_C equal to 36.60 nm, and I/C equal to 0.76, with the objective of maximum power density (P_max). For the gradient CCL, the best gradient distribution enables Pt loading to increase from the membrane (MEM) side to the gas diffusion layer (GDL) side and the ionomer volume fraction to decrease from the MEM side to the GDL side. Full article

This study focuses on the icing problem of electrified railway contact lines. Using computational fluid dynamic (CFD) numerical simulations, a three-dimensional mesh model of the CuAg0.1AC120 contact line was developed. This study reveals the effects of environmental factors such as droplet diameter, air–liquid water content (LWC), and ambient temperature on the icing morphology. The results show that the asymmetric cross-sectional structure of the contact line causes localized droplet accumulation in the groove areas, leading to distinctly non-uniform and directional ice formation. At high wind speeds, secondary icing is observed on the leeward side, where droplets are carried by bypass airflow—this phenomenon is not prominent in standard conductors. Additionally, the contact line exhibits a more sensitive response to temperature and air moisture content changes, suggesting that it is more suited to a localized anti-icing strategy. The numerical model developed in this study provides a theoretical foundation for predicting ice loads on complex section conductors and supports the design optimization and maintenance of high-speed railway catenary systems. Full article

Seafloor communities along the eastern Svalbard coast remain poorly studied. To address this gap, we sampled benthic organisms on the soft sediments of Storfjord in 2017 and 2019, a large fjord predominantly influenced by cold Arctic waters, to study the local fauna and identify the key environmental drivers shaping community structure. In total, 314 taxa were recorded, with an increase in abundance (from 3923 to 8977 ind. m⁻², mean 6090 ind. m⁻²) and a decline in biomass (ranging from 265 to 104 g m⁻², mean 188 g m⁻²) toward the outer part of the fjord. However, no clear spatial trends were observed for alpha diversity (approximately 100 species per 0.3 m²) or the Shannon index (mean 3 per station). The primary factors influencing benthic abundance were the duration of the ice-free period (IFP) and the degree of siltation (DS), both of which are proxies for trophic conditions. The prevailing taxa displayed a high tolerance to temperature fluctuations and seasonal variability in nutrient inputs. Benthic biomass showed a negative relationship with IFP, DS, and water depth, but it was positively correlated with the proportion of fine-grained sediment. The Yoldia hyperborea community (mean abundance: 3700 ind. m⁻², mean biomass: 227 g m⁻²) was associated with Arctic waters characterized by higher inorganic suspension loads. In contrast, areas with reduced or weaker sedimentation were dominated by the communities of Maldane sarsi (6212 ind m⁻², 226 g m⁻²) and Maldane sarsi + Nemertini g.sp. (5568 ind m⁻², 165 g m⁻²). The Spiochaetopterus typicus community (7824 ind m⁻², 139 g m⁻²) was observed in areas under moderate influence of Atlantic waters, characterized by low sedimentation rates and increased fresh detritus flux. Full article

Sea ice and the resulting loads are major safety concerns for vessels operating in ice-covered regions. This study presents a tailored sea ice and local ice load monitoring system specifically designed for polar cargo vessels. The system employs shipboard cameras coupled with a DeepLab v3+-based algorithm to achieve real-time ice concentration identification, demonstrating 90.68% accuracy when validated against historical Arctic Sea ice imagery. For structural load monitoring, we developed a hybrid methodology integrating numerical simulations, full-scale strain measurements, and classification society standards, enabling the precise evaluation of ice-induced structural responses. The system’s operational process is demonstrated through comprehensive case studies of characteristic ice collision scenarios. Furthermore, this system serves as an exemplary implementation of a navigation assistance framework for polar cargo vessels, offering both real-time operational guidance and long-term reference data for enhancing ice navigation safety. Full article

Sphingomyelin nanoemulsions (SNs) are promising drug delivery systems with potential for treating challenging tumors, including non-small cell lung cancer (NSCLC), which has a poor prognosis and a 5-year survival rate below 5%. Understanding the toxicity mechanisms and intracellular behavior of SNs is crucial for optimizing their therapeutic application. This study aims to investigate the interaction between SNs and A549 lung adenocarcinoma cells, focusing on their cytotoxic effects and mechanisms of cellular toxicity. SNs were synthesized and characterized for size, surface charge, and stability. A549 cells were treated with varying concentrations of SNs, and cellular uptake pathways were assessed using inhibitors of energy-dependent processes. Cytotoxicity was evaluated through an alamarBlue assay to determine the IC₅₀ value after 24 h. Mechanisms of toxicity, including lysosomal and mitochondrial involvement, were examined using co-localization studies, mitochondrial membrane potential assays, and markers of apoptosis. SNs exhibited rapid cellular uptake via energy-dependent pathways. The IC₅₀ concentration for A549 cells was 0.89 ± 0.15 mg/mL, suggesting favorable cytocompatibility compared to other nanocarriers. At IC₅₀, SNs induced apoptosis characterized by lysosomal damage, mitochondrial membrane permeabilization, and the release of apoptotic factors. These effects disrupted autophagic flux and contributed to cell death, demonstrating potential for overcoming drug resistance. Resveratrol-loaded SNs showed enhanced cytotoxicity, supporting their application as targeted drug delivery vehicles. This study highlights the potential of SNs as efficient drug delivery systems for NSCLC therapy, offering insights into their cellular interactions and toxicity mechanisms. These findings pave the way for the rational design of SN-based therapeutic platforms for cancer and other mitochondria-related diseases. Full article

To improve the accuracy of the icing prediction model for overhead transmission lines, a physics-guided Fast-Slow Transformer icing prediction model for overhead transmission lines is proposed, which is based on the icing prediction model with meteorological input characteristics. First, the ice cover data is segmented into different time resolutions through Fourier transform; a transformer model based on Fourier transform is constructed to capture the local and global correlations of the ice cover data; then, according to the calculation model of the comprehensive load on the conductor and the conductor state equation, the variation law of ice thickness, temperature, wind speed, and tension is analyzed, and the model loss function is constructed according to the variation law to guide the training process of the model. Finally, the sample mixing enhancement algorithm is used to reduce the overfitting problem and improve the generalization performance of the prediction model. The results show that the proposed prediction model can consider the mechanical constraints in the ice growth process and accurately capture the dependence between ice cover and meteorology. Compared with traditional prediction models such as LSTM (Long Short-Term Memory) networks, its mean square error, mean absolute error, and mean absolute percentage error are reduced by 0.464–0.674, 0.41–0.53, and 8.87–11.5%, respectively, while the coefficient of determination (R²) is increased by 0.2–0.29. Full article

Guyed towers in high-voltage transmission lines consist of the tower body, guy wire system, and foundation. A well-designed guy wire system with optimized tension levels is essential to maintain the stability of the tower under wind loads and other external forces. In practical operation, to prevent excessive corrosion of the pinned metal components at the tower base, these connections are often encased in concrete, altering the base connection conditions and affecting the structural forces on the tower. This study develops a finite element analysis model based on two guyed tower structures from a high-voltage transmission line project. By measuring the actual tensions of the guy wire and testing the basic material performance, this model considers the effects of varying base connection conditions and different guy wire tension levels. Under designed ice load and extreme wind load conditions, the analysis focuses on changes in tower body stress, tower-top displacement and inclination, and guy wire forces. The results indicate that when the tower base is uniformly pinned or fixed, the initial guy wire tension has minimal impact on maximum tower stress but significantly affects maximum tower displacement and inclination when the tower was under the ice and wind load conditions. The base connection condition has a pronounced impact on the stress states of the tower and guy wire system, especially under the designed wind loads. In particular, when the base is fixed, the maximum base stress in Tower 1 under the wind loads is 270% higher than in a pinned condition. The initial guy wire tension level significantly affects the guy wire force under the ice and wind loads; for example, when Tower 1 is subjected to approximately 85% of the design level of high wind load, some guy wires reach full relaxation prematurely, presenting localized strength failure risks at the tower foot, potentially threatening the tower safety under extreme design loads. Full article

There has been a progressive global increase in the usage of electric vehicles in this dispensation. This is mostly due to the need to decarbonise the transport sector and mitigate the concerns of climate change and depleting oil reserves of which South Africa is not an exception. In fact, South Africa is the country with the highest CO₂ emissions in Africa and can reduce its carbon footprint by embracing green mobility. Compared to the internal combustion engine (ICE) market, the electric vehicle (EV) market in South Africa is still in its early stages, with limited local production and usage since its introduction to the country’s automotive sector in 2013. Therefore, in this study, the usage of EVs in South Africa, along with adoption rates and challenges were carried out to make a stronger case that would offer a better pathway for increased EV adoption in the country. It has been discovered that the slow adoption rate of EVs is due to factors such as EV procurement, ownership costs, vehicle parts, safety issues, battery technology, tax and import duties, load shedding, and availability of charging stations. This paper also provides insights into government policies, funding, and other efforts that can support EV adoption in the country through the analyses of primary and secondary data. The proposed strategies include the introduction of tax rebates on imported EVs, local production of EVs and their vehicle parts, retrofitting ICE vehicles to EVs, and science-informed strategies to transition from ICE to electric vehicles. Furthermore, more renewable energy grid integration and renewable energy-powered EV charging stations would also provide support for the energy required to power EVs even during load shedding. Preliminary findings from the survey also suggest that the local production of EV components and government-sponsored training programmes on various EV skills are crucial for increasing the adoption rate of EVs in the country. Full article

Background/Objectives: Doxorubicin (DOX) is commonly used as a chemotherapeutic agent for the treatment of breast cancer. Nonetheless, its systemic delivery via intravenous injection and toxicity towards healthy tissues commonly result in a broad range of detrimental side effects. Breast cancer severity was previously shown to be correlated with TRPC1 channel expression that conferred upon it enhanced vulnerability to pulsed electromagnetic field (PEMF) therapy. PEMF therapy was also previously shown to enhance breast cancer cell vulnerability to DOX in vitro and in vivo that correlated with TRPC1 expression and mitochondrial respiratory rates. Methods: DOX uptake was assessed by measuring its innate autofluorescence within murine 4T1 or human MCF7 breast cancer cells following magnetic exposure. Cellular vulnerability to doxorubicin uptake was assessed by monitoring mitochondrial activity and cellular DNA content. Results: Here, we demonstrate that 10 min of PEMF exposure could augment DOX uptake into 4T1 and MCF7 breast cancer cells. DOX uptake could be increased by TRPC1 overexpression, whereas inhibiting the activity of TRPC1 channels with SKF-96356 or genetic knockdown, precluded DOX uptake. PEMF exposure enhances DOX-mediated killing of breast cancer cells, reducing the IC₅₀ value of DOX by half, whereas muscle cells, representative of collateral tissues, were less sensitive to PEMF-enhanced DOX-mediated cytotoxicity. Vesicular loading of DOX correlated with TRPC1 expression. Conclusions: This study presents a novel TRPC1-mediated mechanism through which PEMF therapy may enhance DOX cytotoxicity in breast cancer cells, paving the way for the development of localized non-invasive PEMF platforms to improve cancer outcomes with lower systemic levels of DOX. Full article

Local ice pressure refers to the ice pressure exerted on a very small area of a structure during ice failure. The existence of high-pressure zones may lead to local deformation and damage to ice-resistant structures, posing a serious threat to the overall structural stability. This study simulates the interaction between sea ice and structures through model tests, analyzing the timing of extreme local ice pressures. The results show that at low loading speeds, there is a 50% probability that the extreme local ice pressure occurs at the peak of the global ice force, while at high loading speeds, this probability drops to around 25%. Further investigation into the relationship between the global ice force peak, ice thickness, loading speed, and local area with local ice pressure amplitude reveals that the local ice pressure amplitude decreases with increasing loading speed and increases with ice thickness. Based on the area averaging method for square regions, the relationship between local ice pressure amplitude and local area is studied, showing that ice thickness, local width, and loading speed all influence the pressure–area relationship. Based on the square area averaging method, the relationship between the local ice pressure amplitude and the local area was studied. It was found that a linear relationship exists between the power function coefficient of local ice pressure–area and the thickness-to-width ratio. Compared to brittle failure, the local ice pressure amplitude under ductile failure of the ice sheet is more significantly affected by ice thickness. This study provides a foundation and reference for the analysis of ice-resistant performance and structural design of polar marine engineering structures. Full article

This paper presents a framework for structural analysis of icebreakers during ramming of first-year ice ridges. The framework links the ice-ridge load and the structural analysis based on the physical characteristics of ship–ice-ridge interactions. A ship–ice-ridge interaction study was conducted to demonstrate the feasibility of the proposed framework. A PC-2 icebreaker was chosen for the ship–ice interaction study, and the geometrical and physical properties of the ice ridge were determined based on empirical data. The ice ridge was modeled by solid elements equipped with the continuous surface cap model (CSCM). To validate the approach, the simulated ice resistance was computed using the Lindqvist solution and in situ tests of R/V Xuelong 2. First, the local ice-induced pressure on the hull shell was determined based on numerical simulations. Subsequently, the local ice pressure was applied to local deformable sub-structural models of the PC-2 icebreaker hull by means of triangular impulse loads. Finally, the structural response of sub-structural models with refined meshes was computed. This case study demonstrates that the proposed framework is suitable for structural analysis of ice-induced stresses in local hull components. The results show that the ice load and the structural response obtained based on the four first-year ice-ridge models show obvious differences. Furthermore, the ice load and corresponding structural response increases with the width of the ridge and with increasing ship speed. Full article

Ice loads are critical forces that impact the structural integrity of offshore equipment in high-latitude sea areas and play a pivotal role in the design of structures in ice-prone regions. The primary objective of this study is to investigate both experimental and numerical approaches to analyze ice loads on marine structures, elucidate their characteristics and patterns, and offer technical support for the design of structures in ice-prone areas. To achieve this goal, an ice model was built using polypropylene material, and experiments were conducted in a wave flume at room temperature to measure the ice resistance on cylindrical structures. Structural loads were assessed at various ice velocities while maintaining a fixed ice concentration. Furthermore, a high-performance discrete element technology was employed to develop a numerical simulation method for calculating ice resistance on cylindrical structures. Sensitivity analysis was conducted to evaluate the influence of discrete element density on the resistance outcomes. The predicted structural resistance for ice velocities corresponding to the experimental conditions was compared with the results obtained from the model experiment. The research findings indicate that the primary cause of ice resistance is the interaction between the structure and fragmented ice, which leads to collisions, friction, rotation, and local ice accumulation. To quantify the resistance, ice resistance coefficients were defined using an average resistance formula, representing different statistical values. These coefficients were found to remain relatively constant at varying sailing speeds. The results obtained through the discrete element method for ice resistance demonstrated a remarkable agreement with the experimental findings, both in terms of observed phenomena and numerical values. This agreement serves as evidence substantiating the effectiveness of the numerical approach. These methods offer efficient and accurate load prediction solutions for the design of structures in cold regions. Full article

Despite advances in breast cancer treatment, there remains a need for local management of noninvasive, low-grade ductal carcinoma in situ (DCIS). These focal lesions are well suited for local intraductal treatment. Intraductal administration supported target site drug retention, improved efficacy, and reduced systemic exposure. Here, we used a poly(N-isopropyl acrylamide, pNIPAM) nanoparticle delivery system loaded with cytotoxic piplartine and an MAPKAP Kinase 2 inhibitor (YARA) for this purpose. For tumor environment targeting, a collagen-binding peptide SILY (RRANAALKAGELYKSILYGSG-hydrazide) was attached to pNIPAM nanoparticles, and the nanoparticle diameter, zeta potential, drug loading, and release were assessed. The system was evaluated for cytotoxicity in a 2D cell culture and 3D spheroids. In vivo efficacy was evaluated using a chemical carcinogenesis model in female Sprague–Dawley rats. Nanoparticle delivery significantly reduced the IC₅₀ of piplartine (4.9 times) compared to the drug in solution. The combination of piplartine and YARA in nanoparticles further reduced the piplartine IC₅₀ (~15 times). Treatment with these nanoparticles decreased the in vivo tumor incidence (5.2 times). Notably, the concentration of piplartine in mammary glands treated with nanoparticles (35.3 ± 22.4 μg/mL) was substantially higher than in plasma (0.7 ± 0.05 μg/mL), demonstrating targeted drug retention. These results indicate that our nanocarrier system effectively reduced tumor development with low systemic exposure. Full article