Search Results (202)

The National Adaptation Plan of Bangladesh identifies eleven climate-stressed zones, placing nearly 100 million people at high risk of climate-related hazards. Vulnerable groups such as the poor, floating populations, daily laborers, and slum dwellers are particularly affected. However, there is a lack of data on climate-sensitive diseases and related hospital visits in these areas. This study explored the prevalence of such diseases using the Delphi method through focus group discussions with 493 healthcare professionals from 153 hospitals in 156 upazilas across 21 districts and ten zones. Participants were selected by district Civil Surgeons. Key climate-sensitive diseases identified included malnutrition, diarrhea, pneumonia, respiratory infections, typhoid, skin diseases, hypertension, cholera, mental health disorders, hepatitis, heat stroke, and dengue. Seasonal surges in hospital visits were noted, influenced by factors like extreme heat, air pollution, floods, water contamination, poor sanitation, salinity, and disease vectors. Some diseases were zone-specific, while others were widespread. Regions with fewer hospital visits often had higher disease burdens, indicating under-reporting or lack of access. The findings highlight the need for area-specific adaptation strategies and updates to the Health National Adaptation Plan. Strengthening resilience through targeted investment and preventive measures is crucial to reducing health risks from climate change. Full article

This study evaluated the effects of conventional cigarette smoke compared to aerosol from a heat-non-burn tobacco product on the color stability of two UDMA-based dental composite resins, namely a monochromatic (Omnichroma) and a polychromatic (Vittra APS) resin. Twenty disc-shaped specimens were prepared, divided into two groups of ten, and exposed to 105 cigarettes or 105 aerosol tobacco sticks via a custom-made smoking chamber. Puff duration was 2 s, with a 60 s interval between puffs in which smoke saturated the chamber for 30 s; then, clean air was introduced into the chamber for 30 s. Six puffs and six intervals were simulated. Color parameters were measured before and after exposure and following brushing of each specimen with 15 strokes. Color differences were determined based on the CIEDE2000 formula. Significant color change was found in all specimens exposed to cigarette and tobacco aerosol. The highest color-change mean value was obtained from composite resin exposed to cigarette smoke. Although both cigarette and thermal heating systems cause discoloration, the aerosol causes reduced composite resin discoloration, which compromises aesthetics and increases patient dissatisfaction, impacting the overall dental care. Color stability is the hallmark of success, as it is the main reason for replacing dental restorations. Full article

Background and Objectives: Military capability may be reduced in hot environments with individuals at risk of exertional heat stroke (EHS). Heat tolerance testing (HTT) can be used to indicate readiness to return to duty following EHS. HTT traditionally relies on rectal core temperature (T_re) assessment via a rectal probe. This study investigated the use of gastrointestinal core temperature (T_gi) as an alternative to T_re during HTT. A secondary aim was to compare physiological factors between heat-tolerant and heat-intolerant trials. Materials and Methods: Australian Defence Force personnel undergoing HTT following known or suspected heat stroke volunteered (n = 23 cases participating in 26 trials) along with 14 controls with no known heat illness history. Confusion matrices enabled comparison of HTT outcome based on T_gi and T_re. The validity of T_gi compared to T_re during HTT was assessed using correlation and bias. Comparisons between heat-tolerant and intolerant trials were performed using non-parametric tests. Results: Although T_gi correlated closely with T_re (Spearman’s rank correlation $\rho$ = 0.893; median bias 0.2 °C) there was no consistent pattern in the differences between measures. Importantly, the two measures only agreed on heat tolerance outcome in 80% of trials with T_gi failing to detect heat intolerance identified by T_re in 6 of 8 trials. If T_gi was relied upon for diagnostic outcome, return to duty may occur before full recovery. None of the assessed covariates were related to the difference between T_re and T_gi. In addition, resting heart rate and systolic blood pressure were significantly lower and body surface area to mass ratio significantly higher in heat-tolerant compared to intolerant trials. Conclusions: It is not recommended to rely on T_gi instead of T_re during HTT. Resting heart rate and systolic blood pressure findings point to the importance of aerobic exercise in conveying heat tolerance along with body composition. Full article

Weather patterns substantially influence extreme weathers in Japan. Extreme high temperature events can cause serious health problems, including heat stroke. Therefore, understanding weather patterns, along with their impacts on human health, is critically important for developing effective public health measures. This study examines the impact of weather patterns on heat stroke risk, focusing on a two-tiered high-pressure system (DH: double high) consisting of a lower tropospheric western Pacific subtropical high (WPSH) and an overlapping upper tropospheric South Asian high (SAH), which is thought to cause high-temperature events in Japan. In this study, the self-organizing map technique was utilized to investigate the relationship between pressure patterns and the number of heat stroke patients in four populous cities. The study period covers July and August from 2008 to 2021. The results show that the average number of heat stroke patients in these cities is higher on DH days than on WPSH days in which SAH is absent. The probability of an extremely high daily number of heat stroke patients is more than twice as high on DH days compared to WPSH days. Notably, this result remains true even when WPSH and DH days are compared within the same air temperature range. This is attributable to the higher humidity and stronger solar radiation under DH conditions, which enhances the risk of heat stroke. Large-scale circulation anomalies similar to the Pacific–Japan teleconnection are found on DH days, suggesting that both high humidity and cloudless conditions are among the large-scale features controlled by this teleconnection. Early countermeasures to mitigate heat stroke risk, including advisories for outdoor activities, should be taken when DH-like weather patterns are predicted. Full article

Hydrogen compression is a critical process in hydrogen storage and distribution, particularly for energy infrastructure and transportation. As hydrogen technologies expand beyond limited industrial applications, they are increasingly supporting the green economy, including offshore energy systems, smart ports, and sustainable marine industries. Efficient compression technologies are essential for ensuring reliable hydrogen storage and distribution across these sectors. This study focuses on optimizing hydrogen compression using a Liquid Piston Hydrogen Compressor through numerical simulations and scaling analysis. The research examines the influence of compression chamber geometry, including variations in radius and height, on thermal behavior and energy efficiency. A computational model was developed using COMSOL Multiphysics^® 6.0, incorporating Computational Fluid Dynamics (CFD) and heat transfer modules to analyze thermodynamic processes. The results highlight temperature distribution in hydrogen, working fluid, and chamber walls at different initial pressures (3.0 MPa and 20.0 MPa) and compression stroke durations. Larger chamber volumes lead to higher temperature increases but reach thermal stabilization. Increasing the chamber volume allows for a significant increase in the performance of the hydraulic compression system with a moderate increase in the temperature of hydrogen. These findings provide insights into optimizing hydrogen compression for enhanced production and broader applications. Full article

Biodiesel and 2-methylfuran (MF) exhibit significant potential as alternative fuels due to advancements in their production techniques. Despite this potential, the low cetane number (CN) of biodiesel–MF (BMF) blends limits their practical use in diesel engines due to poor auto-ignition characteristics and extended ignition delays. This study addresses this issue by investigating the impact of the cetane improver 2-ethylhexyl nitrate (2-EHN) on the performance and emissions of a BMF30 blend. The blend consists of 70% biodiesel and 30% MF, with 2-EHN added at concentrations of 1% and 1.5% to enhance ignition properties. The experiments were conducted on a four-cylinder, four-stroke, direct-injection compression ignition (DICI) engine at a constant speed of 1800 rpm with brake mean effective pressures (BMEP) ranging from 0.13 to 1.13 MPa. The results showed that 2-EHN improved the CN of the BMF30 blend, leading to earlier combustion initiation and longer combustion duration. At low BMEP (0.13 MPa), 2-EHN increased the peak rate of heat release and in-cylinder pressure, whereas at higher BMEP (0.88 MPa), these parameters decreased. The key findings include a reduction in brake-specific fuel consumption (BSFC) by 5.49–7.33% and an increase in brake thermal efficiency (BTE) by 3.30–4.69%. Additionally, NOx emissions decreased by 9.4–17.48%, with the highest reduction observed at 1.5% 2-EHN. CO emissions were reduced by 45.1–85.5% and soot emissions also declined. Hydrocarbon (HC) emissions decreased by 14.56–24.90%. These findings demonstrate that adding 2-EHN to BMF30 blends enhances engine performance, reduces key emissions, and offers a promising alternative fuel for diesel engines. Full article

Background: Ischemic stroke (IS) is a severe condition with limited therapeutic options. Pyroptosis, a type of programmed cell death linked to inflammation, is closely associated with IS-related damage. Studies suggest inflammation aligns with the traditional Chinese medicine (TCM) concept of “fire-heat syndrome”. Huanglian Jiedu Decoction (HLJD), a TCM formula known for clearing heat and purging fire, has shown therapeutic effects on IS, potentially by regulating pyroptosis. Study design: Eight-week-old male mice were divided into six groups: sham operation, model, positive drug, and low-, medium-, and high-dose HLJD groups. After a week of adaptive feeding, mice received respective treatments for five days, followed by modeling on the sixth day, with samples collected 23 h post-perfusion. Analyses included multi-omics, physiology, histopathology, virtual drug screening, target affinity assessment, and molecular biology techniques to measure relevant indicators. Results: HLJD effectively mitigated IS-related damage, maintaining neurological function, reducing ischemic levels, protecting cellular morphology, inhibiting neuronal apoptosis, and preserving blood–brain barrier integrity. Bioinformatics of high-throughput omics data revealed significant activation of pyroptosis and related inflammatory pathways in IS. ScRNA-seq identified neutrophils, macrophages, and microglia as key pyroptotic cell types, suggesting potential therapeutic targets. Network pharmacology and molecular docking identified NLRP3 as a critical target, with 6819 ligand–receptor docking results. SPR molecular fishing, LC-MS, molecular dynamics, and affinity measurements identified small molecules with high affinity for NLRP3. Molecular biology techniques confirmed that HLJD regulates pyroptosis via the classical inflammasome signaling pathway and modulates the inflammatory microenvironment. Conclusions: Following IS, pyroptosis in myeloid cells triggers an inflammatory cascade, leading to neural damage. HLJD may inhibit NLRP3 activity, reducing pyroptosis and associated inflammation, and ultimately mitigating damage. Full article

The escalating summer heat in the Middle East and Northern Africa (MENA) region, particularly in Bahrain, poses a significant threat to human health, prompting the use of water mist systems for immediate heat stress relief and heat stroke treatment. Although these systems are known for their rapid cooling effects, the impact of varying water temperatures on their efficiency is not well understood. This research addressed this gap by investigating the effects of different water temperatures on cooling performance and user comfort in a semi-outdoor environment in Bahrain. Field experiments, comparing mist fan system (MFS) zones with non-misted areas, were conducted alongside user surveys to assess perceived thermal comfort. The findings revealed that lower water temperatures significantly enhanced cooling, with a 7.7 °C water temperature achieving a 4 °C temperature reduction and improving perceived comfort. The MFS effectively shifted participant perceptions from “Hot” or “Slightly Warm” to “Natural” or “Slightly Cool”, confirming its rapid heat mitigation capabilities. Notably, 54.5% of participants preferred the system using the coldest water, citing immediate relief. Despite the substantial cooling benefits, achieving standard thermal comfort during peak heat remained challenging. Future research should explore nozzle optimization, wind effects, water usage, solar-powered system efficiency, and the impact of clothing on thermal comfort. Full article

Studies using large animal models are essential for better understanding the molecular processes underlying neurological diseases, including ischemic stroke, and serve as a robust foundation for evaluating potential therapies. To better understand the complex role of damage-associated molecular pattern molecules (DAMPs) after ischemia, we aimed to determine their expression in the porcine brain affected by ischemic stroke at four time points: 6 h, 24 h, 3 days and 7 days post-stroke. Within the first 24 h after the stroke, we observed the increased expression of several key factors, including calcium-binding proteins, peroxiredoxins, heat shock proteins and interleukins (1α and 1β, IL10, IL17α). Moreover, by day 7, multiple DAMPs were up-regulated, coinciding with an enhanced expression of vascular endothelial growth factor A (VEGFA) in the affected hemisphere. The effects of ischemic stroke were also evident systemically, as indicated by the altered serum levels of both pro- and anti-inflammatory interleukins, reflecting dynamic inflammatory response. To conclude, our findings provide new insights about the time-dependent DAMP activity in a large animal model of ischemic stroke, highlighting the simultaneous occurrence of an ongoing inflammatory response and the possible initiation of vascular remodeling as early as one week after stroke onset. Full article

Research findings reveal that thermal environments precisely regulate the skeletal system through a triple regulation of “structural morphology-cellular dynamics-molecular mechanisms”: At the tissue morphology level, moderate heat exposure can promote increased bone density and longitudinal growth, as well as improved fracture load and yield point, but may negatively affect geometric shape and cortical bone thickness. Continuous high-temperature exposure harms bone structure, manifested as changes in biomechanical characteristics such as decreased toughness and rigidity. At the cellular level, thermal environments directly affect the proliferation/apoptosis balance of osteoblasts and osteoclasts, and by regulating osteocyte network activity and bone marrow mesenchymal stem cell fate decisions, these four cell populations form temperature-dependent metabolic regulatory circuits. At the molecular dimension, heat stress can activate the release of neural factors such as CGRP and NPY, which possess dual regulatory functions promoting both bone formation and resorption; simultaneously achieving coordinated regulation of angiogenesis and fat inhibition through VEGF and TGFβ. The thermal environment–bone regulatory mechanisms revealed in this study have important translational value: they not only provide theoretical basis for biomechanical protection strategies for high-temperature workers and athletes, but also offer innovative entry points for analyzing the pathological mechanisms of heat stroke secondary bone injury and osteoporosis through heat stress-related signaling pathways, while establishing a theoretical foundation for the development of temperature-responsive functionalized biomaterials in bone tissue engineering. Full article

Extreme heat, a leading cause of weather-related morbidity and mortality, particularly affects vulnerable populations such as older people, increasing their risk of stroke. There is a gap between scientific knowledge and policy implementation, particularly regarding climatic risk factors for stroke. This study aims to identify knowledge barriers and enablers and formulate recommendations. We held eight focus groups of participants aged ≥ 60 years (N = 56), a workshop with 36 public health policy experts and stakeholders, and six in-depth interviews with experts. Three main themes emerged: (1) risk perception and responsibility attribution, revealing varying awareness of climate change risk for stroke and complex personal, cultural, and institutional responsibilities; (2) barriers to climate change adaptation, including knowledge gaps, environmental maladaptation, and insufficient governmental resources; and (3) enabling factors and adaptive solutions, highlighting individual coping strategies, education, and collaborative policy interventions. Focus group participants demonstrated diverse adaptive behaviors, while policymakers emphasized interagency collaboration and targeted knowledge dissemination. Older individuals demonstrated limited knowledge about climate change and its health risks. National policies lack effective communication. There is a critical need for knowledge dissemination, coping tools, and solutions for healthcare providers and at-risk groups, particularly regarding the health implications of climate change. Full article

In recent years, living and occupational environments have been increasingly exposed to extreme heat. While the risk of heatstroke rises with greater heat stress, conventional knowledge and safety standards may no longer adequately assess heat stress under such extreme conditions. To address this issue, we propose a method for evaluating heat stress using collective data from wearable biosensors that monitor heart rate and physical activity in a group of workers. The novelty of this approach lies in utilizing collective data from wearable biosensors to assess environmental heat stress rather than individual health status. To quantify heat stress in specific environments or conditions, we introduce the heart rate response intercept, defined as the heart rate at 1 MET when the heart rate response to physical activity is approximated linearly. Using this heat stress index, we examined the effects of ambient temperature, aging, and obesity on heat stress. Our findings indicate that heat stress among obese workers was significantly high and should not be overlooked. Furthermore, because this method can quantify the effectiveness of heatstroke countermeasures, it serves as a valuable tool for improving occupational environments. Full article

The Free Double-Piston Composite Cycle Engine (FDP-CCE) integrates the turbofan engine architecture with the characteristics of piston engines with the aim of improving engine efficiency and decreasing CO₂ emissions. The FDP-CCE features a free-piston design, providing a lighter and more compact structure compared to conventional crankshaft-connected piston engines due to the elimination of mechanical transmissions and lubrication systems. Innovations like air lubrication and increased piston velocities contribute to higher cylinder temperatures, underscoring the need for advanced thermal management strategies. For this reason, in the present work, a heat transfer model to address the thermal management challenges in this innovative engine design is developed. More specifically, a novel filling–discharge model for a two-stroke compression ignition engine is developed, dividing the operational cycle into phases handled by the piston engine and the piston compressor. Special emphasis is given to the implementation of various geometric zones for each piston to optimize the heat transfer between the combustion chamber and the cylinder walls and heads. The final step of this research work involves the integration of piston temperatures into the boundary conditions of an equivalent computational domain to conduct a detailed heat transfer and fluid flow analysis around and on the FDP cylinder. By focusing on these critical aspects, this study establishes a fundamental framework for future aeroengine designs, promoting sustainable propulsion solutions with reduced fuel consumption and emissions. Full article

The recent rise in temperatures in urban areas has raised concerns about various health problems, such as heat-related illnesses. This study quantified the number of individuals exposed to outdoor heat during the daytime in the summertime waterfront area of Tokyo. Conventional meteorological observation and administrative data are insufficient for high-resolution analyses of people flow and heat conditions in urban environments. Therefore, this study introduced a new methodology combining urban computational fluid dynamics (CFD) and mobile phone global positioning system (GPS) data. A numerical simulation was performed to estimate the wet-bulb globe temperature (WBGT) by analyzing fluid dynamics and radiation models. The WBGT in parks was determined to be approximately 27 °C, while the on-road temperature exceeded 29 °C. Simultaneously, pedestrian density was assessed by collecting high-resolution mobile phone GPS data, revealing that pedestrians concentrated near stations, office areas, and shopping districts within a 5 km × 5 km area. Furthermore, a review of heat stroke cases (2010–2020) indicated that combining heat and people flow yielded stronger correlations with the number of heat stroke cases than considering heat alone. Finally, a new heat risk index was established, integrating heat, people flow, and aging rate, which more accurately predicted the heat stroke cases. Full article

Heat stress on workers wearing PPE (Personal protective equipment) in hot outdoor environments is of rising concern, especially in cases when rest breaks and clothing changes are impractical. Mist fan evaporative cooling could provide low-energy continuous cooling, even during work activity. The cooling effect of a misting fan was compared to that of a fan alone, as well as natural convection. A thermal mannequin with heat flux sensors at eight body locations was exposed to an outdoor misting fan while being clothed in typical work clothes and PPE. Work clothes were dry or saturated with water to simulate sweat. The distance from the misting fan ranged from 4 m (wetting common) to 7 m (wetting unlikely). On average, the misting fan had a cooling effect of 0.31 met (18.3 W/m²) higher than natural convection when PPE is worn with wet work clothes, and 0.35 met (20.3 W/m²) higher than when PPE is worn with dry work clothes. This equates to reducing the thermal metabolic load from light industrial work to walking about in office work, or from standing to reclining. Under the ISO 7243 international standard for workers in hot environments, this would increase the acceptable WBGT (wet bulb globe temperature) by over 0.6 °C. Full article