Search Results (347)

Understanding how urban environmental features shape physical activity is crucial for building health-supportive cities, especially under climate change pressures such as rising temperatures and extreme weather. Previous studies emphasized density and accessibility, but the spatial mechanisms driving facility usage remain understudied. This study investigates how land use diversity, the distribution of physical activity facilities, street network structure, and road accessibility shape physical activity behaviours at the neighbourhood scale. Using a 500 m × 500 m grid framework in Xiamen, China, a random forest model combined with Shapley Additive Explanations (SHAP) is employed to quantify the importance of environment indicators. The results demonstrate that road accessibility and street connectivity exert the strongest influence on physical activity facility use, followed by land use diversity and 15 min reachable residential Points of Interests (POIs). Spatial autocorrelation and cluster analysis further reveal that high-impact areas are concentrated in central and southern zones, whereas peripheral regions face accessibility deficits. These findings highlight the value of integrating transport planning and land use configuration to address spatial disparities in facility usage. The study contributes a replicable methodological framework and provides practical insights for advancing equitable and activity-friendly neighbourhood design. Full article

Background: Temperature regulation is impaired in iron-deficient anemic humans and rats at rest during cold exposure. However, there is a paucity of data regarding the interplay of cold exposure, anemia, and exercise on thermal and cardiovascular responses. Therefore, we aimed to explore thermal and cardiovascular responses of individuals with chronic mild iron-deficiency anemia during exercise in the cold compared to controls. Methods: Nine anemic (5 F, 4 M) and nine control (5 F, 4 M) individuals, matched for body fat, size, and mass but different by design in hematological parameters and physical fitness, participated in the study. The participants cycled in cold 11 °C with 40% relative humidity (RH) and neutral (22 °C, 40% RH) conditions at an intensity ~10% below the respiratory threshold until 1 °C increase in rectal temperature (T_re) or 1 h of exercise, whichever occurred first. Results: In the cold, the anemic individuals showed a lower rate of T_re rise (p = 0.047) and lower mean skin temperature (T_sk) (p = 0.03) compared to controls, while only controls increased heat production compared to the neutral condition (p = 0.035). Moreover, the anemic group exhibited an exaggerated blood pressure response in the cold compared to the neutral environment (p < 0.05), due to heightened total peripheral resistance (p < 0.05) and vasomotor response (p < 0.001). Conclusions: In summary, chronic mild iron-deficiency anemia impaired temperature regulation as judged from the lower rate of T_re rise and an inability to activate further the metabolism at cold. Concomitantly, the anemic participants demonstrated increased cardiovascular strain. This is notable because anemia and these environmental conditions are encountered in the workplace, recreational activities, and athletic endeavors. These findings may inform safety guidelines for athletes, workers, and patients exposed to cold environments. Full article

Monitoring heart rate (HR) and peripheral oxygen saturation (SpO₂) in underwater environments has gained increasing importance due to the expanding popularity of diving activities such as SCUBA diving, freediving, and professional underwater operations. These physiological parameters are critical indicators for detecting adaptive responses and early signs of physiological distress caused by environmental stressors like elevated ambient pressure, hypoxia, cold temperatures, and psychological stress. Although recent advances in wearable sensor technologies offer new opportunities for real-time physiological monitoring underwater, significant limitations persist due to issues such as signal interference, cold-induced vasoconstriction, sensor durability, and the complexity of reliably measuring these parameters in dynamic underwater conditions. Evidence shows HR can fall by more than 50% in freedivers and SpO₂ may decline to below 50% during repeated dives, with proposed depth-specific thresholds (e.g., <98.5% at 30 m) serving as early warning levels. This review synthesizes current knowledge on the cardiovascular and oxygenation responses observed during diving, explores the technological challenges associated with underwater HR and SpO₂ monitoring, and discusses future directions, including the integration of multisensor platforms and predictive analytics to enhance diver safety and physiological monitoring capabilities. Addressing these technological and methodological gaps holds the potential to substantially improve safety standards and expand the clinical applicability of underwater physiological monitoring systems. Full article

The stability of open-pit mines under low-temperature conditions is critical for safe and efficient coal extraction. However, the mechanisms of rock damage and fracture under combined temperature and stress effects remain unclear, particularly regarding the evolution of mechanical properties under repeated freeze–thaw cycles and varying peripheral pressures. This study investigates the damage and rupture behavior of coal-bearing sandstone in cold-region open-pit mines through experimental testing and theoretical modeling. The research was conducted in three stages: (1) freeze–thaw and peripheral pressure experiments to evaluate mechanical property evolution; (2) acoustic emission monitoring to analyze internal fracture initiation, propagation, and coalescence under temperature–stress coupling; (3) development of a local deterioration model to quantify post-damage strength decay considering low-temperature erosion and freeze–thaw effects. Results show that increasing freeze–thaw cycles leads to a transition from brittle to ductile behavior, while higher peripheral pressures significantly enhance ductility. Mechanical parameters are highly sensitive to peripheral pressure but largely independent of freeze–thaw cycle count. Acoustic emission signals respond strongly to temperature, and temperature–stress coupling governs the three-stage evolution of fracture germination, extension, and penetration. The local deterioration model effectively captures post-peak residual strength and damage evolution. These findings indicate that in regions with higher microcrack density, fault propagation is driven by rapid coalescence under stress concentration, whereas in lower-density regions, it is dominated by gradual fracture growth and temperature-induced expansion. The results provide theoretical guidance for stability assessment and support design in open-pit coal mines in cold environments. Full article

Tunnel portal rocks in southern China, which are exposed to intense solar radiation and temperature fluctuations, are susceptible to thermal stress, which directly or indirectly affects the safety, stability, and normal use of a tunnel and its peripheral structures. Fractures act as conduits for solar radiation energy, converting it into thermal energy within the rock, thereby altering the thermal stress field. As formation mechanisms of rock, fractures are complex, and the nonlinear thermal conduction at fracture tips leads to thermal stress concentration. A parabolic shape function for the heat source and thermal stress at tips of rock fractures is herein proposed, and the thermal stress field of fractured rocks under solar radiation is obtained. The applicability of different fracture heat source functions for analyzing the effects of heat on rocks with varying thermodynamic properties is discussed. Compared with a linear heat source function, the thermal stress values of rock fracture tips are larger. The daily maximum ${\sigma }_{\theta \max }$ increases by 8.14% when ${\alpha }_c=0.05$ based on the parabolic heat source function, providing more conservative results for the thermal stability analysis of fractured rock under solar radiation. Parabolic heat source functions are more reasonable for soft rocks with high thermal conductivity and low thermal deformation, while linear heat source functions are more appropriate for hard rocks. A parabolic heat source function is a typical function for analyzing the effects of heat on fractured rocks under solar radiation. Full article

Background: Diabetic foot ulcers (DFUs) in patients with peripheral artery disease (PAD) are difficult to treat and associated with poor healing outcomes. Photobiomodulation therapy (PBMT) and exercise have shown individual benefits, but evidence on their combined effects is limited. Objective: To evaluate whether PBMT combined with resistance exercise improves wound healing and walking ability in patients with DFU and PAD. Methods: In this pilot randomized trial, 11 patients with DFU and PAD were allocated to either PBMT plus supervised exercise or exercise alone for 4 weeks. Outcome measures included wound size, skin temperature, and 6-min walking distance. Results: PBMT combined with exercise improved wound healing and walking capacity compared with baseline; however, no significant between-group differences were observed. A positive correlation was observed between post-PBMT plantar skin temperature and percentage of wound reduction. Conclusions: PBMT combined with resistance exercise may enhance wound healing and functional mobility in patients with DFU and PAD. Full article

Background/Objectives: Platelet counts can be affected by storage conditions, potentially leading to pseudothrombocytopenia. The present study aimed to investigate temperature-dependent changes in platelet counts and morphology in whole blood samples anticoagulated with heparin or EDTA. We also examined the molecular mechanism of cold-induced aggregation via integrin GPIIb/IIIa–fibrinogen interaction using established bioinformatics technologies (docking simulation). Methods: Peripheral blood was collected from healthy volunteers (n = 6) and treated with either heparin or EDTA. The samples were stored at 4 °C, room temperature, or incubated at 37 °C. Platelet counts were measured using an automated hematology analyzer. The morphology of various blood cells in smears was assessed using the May-Grünwald Giemsa staining method. Docking simulations using an available software (HADDOCK 2.4) were performed to evaluate integrin–fibrinogen binding at different temperatures. Results: In automated blood cell counting, platelet counts in heparinized blood were significantly decreased under low-temperature conditions (4 °C), but this decrease was restored to levels comparable to those at room temperature upon warming to 37 °C (p < 0.05). No significant changes were observed in EDTA-treated samples. Microscopical findings showed platelet aggregation only in heparinized samples at 4 °C, with normal morphology restored upon warming (37 °C). Docking simulations estimated stronger integrin GPIIb/IIIa–fibrinogen binding at 4 °C than at 37 °C (p = 0.0286), suggesting temperature-dependent enhancement of molecular interactions. Conclusions: These findings indicate that heparin can induce reversible platelet aggregation at low temperatures in whole blood samples, leading to pseudothrombocytopenia. This phenomenon may be mediated by increased integrin GPIIb/IIIa–fibrinogen binding. Full article

The presence of a minimum quantity lubrication (MQL) under the conditions of a burnishing process can contribute to an improvement in the process performance by reducing the heights of the resulting surface asperities, by decreasing the temperature values, and by diminishing the size of the burnishing force components. On the other hand, there are situations in which it is possible to increase the service life of the parts made of EN AW-2007 aluminum alloy by applying a burnishing process. To verify how the results of applying a burnishing process applied to cylindrical specimens in the aluminum alloy when using and not using a minimum quantity lubrication, an experimental research based on a planned variation between certain limits of the values of the peripheral speed and the feed rate has been conceived and materialized. The experimental results were processed mathematically. It has been found that by using the minimum quantity of mineral oil type Valona MS7023 HC, it was possible to reduce the value of the Sa roughness parameter by up to 18%, a decrease in temperature by about 20 °C, and the size of the burnishing force by up to 45%. Full article

This paper presents a literature review of low-power hybrid wind–photovoltaic (PV) systems and introduces a 3 m diameter prototype rotor featuring twelve PV-coated pivoting blades stiffened by a peripheral rim. Existing solutions—foldable umbrella concepts, Darrieus rotors with PV-integrated blades, and morphing blades—are surveyed, and current gaps in simultaneous wind + PV co-generation on a single moving structure are highlighted. Key performance indicators such as power coefficient (C_p), DC ripple, cell temperature difference (ΔT), and levelised cost of energy (LCOE) are defined, and an integrated assessment methodology is proposed based on blade element momentum (BEM) and computational fluid dynamics (CFD) modelling, dynamic current–voltage (I–V) testing, and failure modes and effects analysis (FMEA) to evaluate system performance and reliability. Preliminary results point to moderate aerodynamic penalties (ΔC_p ≈ 5–8%), PV output during rotation equal to 15–25% of the nominal PV power (P_PV), and an estimated 70–75% reduction in blade–root bending moment when the peripheral ring converts each blade from a cantilever to a simply supported member, resulting in increased blade stiffness. Major challenges include the collective pitch mechanism, dynamic shading, and wear of rotating components (slip rings); however, the suggested technical measures—maximum power point tracking (MPPT), string segmentation, and redundant braking—keep performance within acceptable limits. This study concludes that the concept shows promise for distributed microgeneration, provided extensive experimental validation and IEC 61400-2-compliant standardisation are pursued. This paper has a dual scope: (i) a concise literature review relevant to low-Re flat-blade aerodynamics and ring-stiffened rotor structures and (ii) a multi-fidelity aero-structural study that culminates in a 3 m prototype proposal. We present the first evaluation of a hybrid wind–PV rotor employing untwisted flat-plate blades stiffened by a peripheral ring. Using low-Re BEM for preliminary loading, steady-state RANS-CFD (k-ω SST) for validation, and elastic FEM for sizing, we assemble a coherent load/performance dataset. After upsizing the hub pins (Ø 30 mm), ring (50 × 50 mm), and spokes (Ø 40 mm), von Mises stresses remain < 25% of the 6061-T6 yield limit and tip deflection ≤ 0.5%·R acrosscut-in (3 m s⁻¹), nominal (5 m s⁻¹), and extreme (25 m s⁻¹) cases. CFD confirms a broad efficiency plateau at λ = 2.4–2.8 for β ≈ 10° and near-zero shaft torque at β = 90°, supporting a three-step pitch schedule (20° start-up → 10° nominal → 90° storm). Cross-model deviations for C_p, torque, and pressure/force distributions remain within ± 10%. This study addresses only the rotor; off-the-shelf generator, brake, screw-pitch, and azimuth/tilt drives are intended for later integration. The results provide a low-cost manufacturable architecture and a validated baseline for full-scale testing and future transient CFD/FEM iterations. Full article

Curved prisms can serve as core components of dispersive spectroscopy and converge light paths, making them widely used in spectral imaging technology. Their positional stability, surface shape errors, and temperature stability in optical systems directly affect the performance of spectral imaging systems. On the basis of the analysis of design indicators and optimization of the support structure for curved prisms, a multipoint flexible adhesive support structure (MPPASS) of large rectangular curved prisms for space-based application is proposed. The novelty of the MPPASS lies in its ability to achieve micro-stress and high stability support for large-aperture rectangular optical elements through the bonding of peripheral small points and the introduction of flexible bonding rings. The design principles of the adhesive support structure were deeply studied, and on this basis, the engineering design, finite element analysis, adhesive testing, and mechanical testing of large curved prisms were completed. The designed curved prism assembly has a maximum deformation displacement of 0.0085 mm and a maximum tilt angle of 0.65” under gravity loading, a first-order frequency of 1003.5 Hz, and a maximum acceleration amplification factor of 3.12 in the X, Y, and Z directions. The root mean square (RMS) variation value of the mirror shape errors for the curved prism assembly was 5.26 nm under a uniform temperature load of 20 ± 1 °C, and the RMS value of the mirror shape errors was 0.019 λ after mechanical testing. The installation surface flatness of 0.02 mm did not significantly affect its mirror shape errors. The experimental results verified the rationality of the design, temperature stability, and mechanical stability of the MPPASS. Full article

This study investigates urban heat vulnerabilities in Seville, Spain, using a multidimensional framework that integrates remote sensing, Space Syntax, and social vulnerability metrics. This research identifies Heat Boundaries (HBs), which are critical urban entities with elevated Land Surface Temperatures (LSTs) that act as barriers to adjacent vulnerable neighbourhoods, disrupting both physical and social continuity and environmental equity, and examines their relationship with the urban syntax and social vulnerability. The analysis spans two temporal scenarios: a Category 3 heatwave on 26 June 2023 and a normal summer day on 14 July 2024, incorporating both daytime and nighttime satellite-derived LST data (Landsat 9 and ECOSTRESS). The results reveal pronounced spatial disparities in thermal exposure. During the heatwave, peripheral zones recorded extreme LSTs exceeding 53 °C, while river-adjacent neighbourhoods recorded up to 7.28 °C less LST averages. In the non-heatwave scenario, LSTs for advantaged neighbourhoods close to the Guadalquivir River were 2.55 °C lower than vulnerable high-density zones and 3.77 °C lower than the peripheries. Nocturnal patterns showed a reversal, with central high-density districts retaining more heat than the peripheries. Correlation analyses indicate strong associations between LST and built-up intensity (NDBI) and a significant inverse correlation with vegetation cover (NDVI). Syntactic indicators revealed that higher Mean Depth values—indicative of spatial segregation—correspond with elevated thermal stress, particularly during nighttime and heatwave scenarios. HBs occupy 17% of the city, predominantly composed of barren land (42%), industrial zones (30%), and transportation infrastructure (28%), and often border areas with high social vulnerability. This study underscores the critical role of spatial configuration in shaping heat exposure and advocates for targeted climate adaptation measures, such as HB rehabilitation, greening interventions, and Connectivity-based design. It also presents preliminary insights for future deep learning applications to automate HB detection and support predictive urban heat resilience planning. Full article

Thirst is usually characterized as an unpleasant sensation provoking drinking of water. The purpose of the present review is to draw attention to the importance of thirst in overall regulation of body fluid homeostasis in health and pathology. Intensity of thirst is determined by signals generated in multiple groups of osmosensitive neurons engaged in dipsogenic and antidipsogenic activities, which are located in the brain cortex, the insula, the amygdala, the median preoptic area, the hypothalamic nuclei and the organum vasculosum laminae terminalis. Water ingestion is also influenced by signals generated in the cardiovascular system, the gastrointestinal system, the pancreas, the liver and the kidney and by changes of body temperature. Regulation of thirst engages the autonomic nervous system and several neuroactive factors synthetized in the brain and the peripheral organs. Among them are components of the renin–angiotensin system, vasopressin, atrial natriuretic peptide, cholecystokinin, ghrelin, gaseous transmitters, cytokines and prostaglandins. Experimental studies provide evidence that elevation of fluid osmolality, which is the most frequent cause of thirst, influences function of the voltage-gated sodium channel and calcium-dependent kinase II subunit alpha. Regulation of thirst may be inappropriate in old age and under some pathological conditions including infections, heart failure, diabetes insipidus, diabetes mellitus, and psychogenic disorders. The molecular background of the abnormal regulation of thirst in the clinical disorders is not yet sufficiently recognized and requires further examination. Full article

Background: Chronic wounds are a growing clinical challenge due to their prolonged healing time and associated healthcare burden. Combined therapeutic approaches, including topical oxygen therapy (TOT) and negative-pressure wound therapy (NPWT), have shown promise in enhancing wound healing. This pilot exploratory study aimed to assess the clinical effectiveness of combined TOT and NPWT in chronic wound treatment and to explore the prognostic value of selected laboratory and thermographic markers. Methods: Eighteen patients with chronic wounds due to type 2 diabetes mellitus or chronic venous insufficiency were treated with either TOT alone (control group) or TOT combined with NPWT (intervention group). Wound characteristics, thermographic data, and laboratory parameters (NLR, MLR, PLR, CRP, and total protein) were collected at baseline and during therapy. The primary endpoints were the total treatment duration and complete wound closure. Statistical analyses were exploratory and used non-parametric tests, correlation analyses, and simple linear regression. Results: Ulcer duration was significantly associated with the wound surface area. Lower serum total protein levels correlated negatively with ulcer duration, wound size, and granulation tissue area. A significant reduction in treatment duration was observed in the intervention group compared to the controls. One strong correlation was found between MLR and peripheral wound temperature on day 7 in the control group. No significant group differences were observed in wound size or thermographic measures after one week of treatment. Conclusions: Combining TOT and NPWT may reduce treatment duration in chronic wound management. Selected laboratory and thermographic markers show promise as prognostic tools. These exploratory findings require confirmation in larger, randomized trials. Full article

Temperature fluctuations caused by climate change and global warming pose a threat to fish. The burbot (lota lota) population is particularly sensitive to increased water temperature, but the systematic impacts of high-temperature exposure on their liver and intestinal health remain unclear. In January of 2025, we collected wild adult burbot individuals from the Ussuri River (water temperature: about 2 °C), China. The burbot were exposed to 2 °C, 7 °C, 12 °C, 17 °C, and 22 °C environments for 96 h; then, the liver and intestinal contents were subsequently collected for histopathology observation, immunohistochemistry, biochemical index assessment, and transcriptome/16S rDNA sequencing analysis. There was obvious liver damage including hepatocyte necrosis, fat vacuoles, and cellular peripheral nuclei. Superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) activities were elevated and subsequently decreased. Additionally, the malondialdehyde (MDA) level significantly increased with increasing temperature. These results indicate that 7 °C (heat stress temperature), 12 °C (tipping point for normal physiological metabolism status), 17 °C (tipping point for individual deaths), and 22 °C (thermal limit) are critical temperatures in terms of the physiological response of burbot during their breeding period. In the hepatic transcriptome profiling, 6538 differentially expressed genes (DEGs) were identified, while KEGG enrichment analysis showed that high-temperature stress could affect normal liver function by regulating energy metabolism, immune, and apoptosis-related pathways. Microbiomics also revealed that acute heat stress could change the intestinal microbe community structure. Additionally, correlation analysis suggested potential regulatory relationships between intestinal microbe taxa and immune/apoptosis-related DEGs in the liver. This study revealed the potential impact of environmental water temperature changes in cold habitats in winter on the physiological adaptability of burbot during the breeding period and provides new insights for the ecological protection of burbot in the context of global climate change and habitat warming. Full article

This study aimed to identify anatomical regions and developmental stages in broiler chickens that serve as reliable thermographic indicators of acute heat stress. Broilers aged 14, 21, 35, and 39 days were exposed to controlled heat stress, and surface temperatures across 12 anatomical regions were recorded using infrared thermography. Thermal response metrics (maximum, minimum, and mean peak variation) were analyzed with repeated-measures ANOVA and eta squared (η²) to quantify the strength of physiological responses. Principal component and cluster analyses grouped body regions based on their thermal sensitivity. The comb and wattle consistently showed the highest temperature increases (ΔT = 2.3–4.1 °C) and strongest effect sizes (η² ≥ 0.70), establishing them as primary thermoregulatory markers. As age increased, more body regions—especially peripheral zones like the drumstick and tail—exhibited strong responses (η² > 0.40), indicating an expansion of thermoregulatory activity. Cluster analysis identified three distinct sensitivity groups, confirming anatomical differences in thermal regulation. Thermographic responses to heat stress in broilers depend on age and region. The comb and wattle are the most reliable biomarkers, while peripheral responses grow more prominent with maturity. These findings support the use of targeted, age-specific infrared thermography for monitoring poultry welfare. Full article