Humid Environment Research Articles

Phosphorus-Water Interaction Drives Active Center Evolution into the Water-Adaptive Structure in the High-Humidity NH3-SCR Reaction.

The impact of water on catalyst activity remains inconclusive due to its dependence on the specific reaction environment. To maximize the exploitation of water's promoting effect, we employed ammonia selective catalytic reduction (NH3-SCR) as a probe reaction and proposed a phosphorus modification strategy for Cu-ZSM-5 catalysts. The objective of this approach was to construct water-adaptive microstructures through directional arrangement. To investigate the effect of phosphorus on the transformation of framework copper sites in humid environments, we conducted comprehensive characterizations and density functional theory calculation. Results reveal that water molecules cleave the oxygen bridges between phosphorus oxide and copper, leading to the formation of active isolated [Cu(OH)]+ groups and phosphate. The phosphate species weaken the interaction between exchanged Cu2+ groups and the zeolite framework, leading to the generation of highly migratory hydrated Cu2+ species. This work will potentially guide the rational design of water-adaptive catalysts for gas pollution abatement in a humid environment.

A Multimodal Perception-Enabled Flexible Memristor with Combined Sensing-Storage-Memory Functions for Enhanced Artificial Injury Recognition.

With the continuous advancement of wearable technology and advanced medical monitoring, there is an increasing demand for electronic devices that can adapt to complex environments and have high perceptual sensitivity. Here, a novel artificial injury perception device based on an Ag/HfOx/ITO/PET flexible memristor is designed to address the limitations of current technologies in multimodal perception and environmental adaptability. The memristor exhibits excellent resistive switching (RS) performance and mechanical flexibility under different bending angles (BAs), temperatures, humid environment, and repetitive folding conditions. Further, the device demonstrates the multimodal perception and conversion capabilities toward voltage, mechanical, and thermal stimuli through current response tests under different conditions, enabling not only the simulation of artificial injury perception but also holds promise for monitoring and controlling the movement of robotic arms. Moreover, the logical operation capability of the memristor-based reconfigurable logic (MRL) gates is also demonstrated, proving the device has great potential applications with sensing, storage, and memory functions. Overall, this study not only provides a direction for the development of the next-generation flexible multimodal sensors, but also has significant implications for technological advancements in many fields such as robotic arms, electronic skin (e-skin), and medical monitoring.

Differentiation between Hydrolytic and Thermo-Oxidative Degradation of Poly(lactic acid) and Poly(lactic acid)/Starch Composites in Warm and Humid Environments.

For the application of poly(lactic acid) (PLA) and PLA/starch composites in technical components such as toys, it is essential to know their degradation behavior under relevant application conditions in a hydrothermal environment. For this purpose, composites made from PLA and native potato starch were produced using twin-screw extruders and then processed into test specimens, which were then subjected to various one-week ageing processes with varying temperatures (23, 50, 70, 90 °C) and humidity levels (10, 50, 75, 90%). This was followed by mechanical characterization (tensile test) and identification of degradation using Gel Permeation Chromatography (GPC), Thermogravimetric Analysis (TGA), Fourier Transform Infrared Spectroscopy (FTIR), and Nuclear Magnetic Resonance spectroscopy (NMR). With increasing temperature and humidity, there was a clear degradation of the PLA, which could be reduced or slowed down by adding 50 wt.% starch, due to increased crystallinity. Hydrolysis was identified as the main degradation mechanism for PLA and PLA/starch composites, especially above the glass transition temperature, with thermo-oxidative degradation also playing a subordinate role. Both hydrolytic degradation and thermo-oxidative degradation led to a reduction in mechanical properties such as tensile strength.

Moisture Power Generation: From Material Selection to Device Structure Optimization.

Moisture power generation (MPG) technology, producing clean and sustainable energy from a humid environment, has drawn significant attention and research efforts in recent years as a means of easing the energy crisis. Despite the rapid progress, MPG technology still faces numerous challenges with the most significant one being the low power-generating performance of individual MPG devices. In this review, we introduce the background and underlying principles of MPG technology while thoroughly explaining how the selection of suitable materials (carbons, polymers, inorganic salts, etc.) and the optimization of the device structure (pore structure, moisture gradient structure, functional group gradient structure, and electrode structure) can address the existing and anticipated challenges. Furthermore, this review highlights the major scientific and engineering hurdles on the way to advancing MPG technology and offers potential insights for the development of high-performance MPG systems.

The Effect of Dust Accumulation on Photovoltaic (PV) Panel Surface in Politeknik Mersing, Johor, Malaysia

Abstract: One of the initiatives aiming at supporting green technology sustainability education in the Politeknik Mersing is the generation of power using renewable energy sources like solar. Considered as more efficient and able to meet current power needs of the community, the generation of electricity from limitless green energy sources is Dust accumulation on the photovoltaic (PV) panel surface has been one of the main environmental elements influencing the declining sun irradiation since Politeknik Mersing located in a tropical rainforest and coastal location. Moreover, in humid environments the accumulation of dust forms mud and contamination on the PV panel surface, which subsequently reduces the relative power efficiency of PV by up to 30%. Therefore, the study has been carried out to investigate the effects of dust accumulation on PV panel surfaces on the amount of output power generated by the PV system. While the lowest relative performance of 69.6% occurred at a 30° tilt angle, the best relative performance of 97% was obtained at a 0° tilt angle during peak solar hours. The relative power efficiency was used to analyse the performance of PV panels under clean and dusty conditions since there was no pyranometer to measure solar irradiation. Several tilt angles (0°, 10°, 20°, and 30°) were assessed in order to situate the panel optimally with respect to the latitude of the location and peak solar hours (10:00 am, 11:00 am, 12:00 pm, and 1:00 pm). The performance of the PV system was evaluated using total output power that is derived from open-circuit voltage (Voc) and short-circuit current (Isc). Results showed that dust accumulation affects the efficiency of PV panels thus necessitating effective maintenance strategies within such environments.

Indoor air disinfection by non thermal atmospheric pressure plasma: a comparative study of performance in low and high humidity environments

Atmospheric pressure plasma (APP) has intrigued the interest of researchers for various applications such as disinfection, air purification, etc. In this context, a deeper understanding of the correlation between APP’s characteristics like discharge parameters, active species composition, and eradication of airborne microorganisms with varying relative humidity (RH) has been examined using a dielectric barrier discharge based atmospheric pressure plasma (DBD-APP) source. One of the electrodes of the developed DBD-APP source has been coated with TiO2 nanoparticles to enhance the generation of reactive species during the discharge process. The results show that, even with the same peak-to-peak applied voltage, the peak-to-peak current and discharge power decrease with increasing RH. Optical emission spectroscopy (OES) is used to determine the relative emission intensity of the reactive species, whereas spectrophotometry is used to quantify the reactive species produced by the plasma at various parameters. Instead of UV radiation, the plasma-produced highly energetic electrons activates the TiO2 nanoparticles for electron–hole pair generation. The geometry of the plasma device has played an important role in generating high energy electrons. From the developed DBD-APP source, the airborne microorganism’s disinfection efficiency of ∼95.8% and ∼98.7% has been achieved in the total bacterial counts (TBCs) and total fungal counts (TFCs) at an RH range of 70%–90%, in just 20 min of continuous operation. However, in the RH range of 20%–40%, the inactivation efficiency dropped to ∼78.8% and ∼87.5% for the TBCs and TFCs, respectively. The outcome indicates that higher humidity levels are better for indoor air purification using DBD-APP sources and that plasma with a circulation system can effectively disinfect indoor environments.

Interfacial Study of Steel Joints Prepared with a Catechol-Modified Epoxy Adhesive with Enhanced Bonding Performance and Durability.

Bonding is widely used in aircraft and vehicles due to its light weight and simple process, but its strength decreases sharply in hot and humid environments. Anodization treatment, used for enhancing aging performance, is environmentally harmful and unsuitable for steel. In this study, a catechol-modified epoxy adhesive (CMEA) was prepared on a hectogram scale. Comparative analysis with phenol-modified epoxy adhesive (PMEA) and pristine epoxy adhesive (EA) revealed that the underwater bonding of CMEA (13.0 MPa) on stainless steel (SS) significantly outperformed the two control groups. Moreover, after 32 days of hydrothermal aging at 50 °C, CMEA preserved 73.9% of its initial bonding strength, while PMEA and EA retained 59.8 and 11.4%, respectively. Furthermore, X-ray photoelectron spectroscopy (XPS) etching at different times to analyze the interface between adhesives and the SS substrate indicated a marked increase in the O-H/O2- value at the interface between CMEA and the SS substrate compared to the two control groups. The above results demonstrated that the catechol-modified adhesive enhanced the bonding and aging properties of the adhesive, possibly due to the formation of a higher density of hydroxyl groups at the interface between the adhesive and the SS substrate. These findings contribute to the understanding of the enhancement mechanism of catechol in improving the bonding and aging properties of adhesives and suggest a feasible direction for designing adhesives with high bonding strength and high durability.

A solar-driven atmospheric water extractor for off-grid freshwater generation and irrigation

Solar-driven atmospheric water extraction (SAWE) is a sustainable technology for decentralized freshwater supply. However, most SAWE systems produce water intermittently due to the cyclic nature, with adoption hindered by complex design requirements or periodic manual operations. Herein, a fully passive SAWE system that can continuously produce freshwater under sunlight is presented. By optimizing the three-dimensional architecture to facilitate spontaneous mass transport and efficient energy utilization, this system can consistently produce 0.65 L m−2 h−1 of freshwater under 1-sun illumination at 90% relative humidity (RH) and functions in arid environments with an RH as low as 40%. We test the practical performance of a scaled-up system in Thuwal, Saudi Arabia over 35 days across two seasons. The system produces 2.0–3.0 L m−2 per day of freshwater during the summer and 1.0–2.8 L m−2 per day of freshwater during the fall, without requiring additional maintenance. Intriguingly, we demonstrate the system’s potential for off-grid irrigation by successfully growing cabbage plants using atmospheric water. This passive SAWE system, harnessing solar energy to continuously extract moisture from air for drinking and irrigation, offers a promising solution to address the intertwined challenges of energy, water, and food supply, particularly for remote and water-scarce regions.

Effect of Au nanoparticles on mitigating the negative impacts of humidity on ZnO gas sensors to detect triethylamine at room temperature

The impact of humidity on the efficiency of gas sensors has become highlighted in the realm of gas detection. Due to the complex relationship between humidity and gas sensor performance, the development of gas sensors has recently focused on minimizing humidity-related interference. This research aims to address humidity-related challenges in zinc oxide (ZnO) gas sensors designed to detect triethylamine. The ZnO nanostructures (NSs) were synthesized using thermal decomposition methods at varying temperatures (380 °C, 480 °C, and 580 °C) and annealing times (3 h, 7 h, 12 h, and 21 h). X-ray diffraction (XRD) confirmed the formation of a wurtzite hexagonal close-packed structure in ZnO NSs. Scanning electron microscopy (SEM) images provided insights into the morphologies of ZnO NSs at different annealing temperatures, while energy dispersive spectroscopy (EDS) demonstrated the elemental distribution. Subsequently, gold (Au) nanoparticles were uniformly sputtered onto ZnO sensors with thickness variations (0.1 nm, 0.6 nm, 1 nm, 5 nm, and 10 nm). XPS was employed to analyse the elemental composition and oxygen vacancies of the synthesized sensing materials. The effectiveness of 0.6 nm-thick Au nanoparticles in mitigating humidity effects was observed in ZnO sensors synthesized at 380 °C. The results indicated that ZnO sensors coated with 0.6 nm-thick Au nanoparticles exhibited highly stable responses to ethanol and triethylamine at different humidity levels from 50 % to 90 %. Notably, these sensors demonstrated promising selectivity towards triethylamine (with a response of 17.57) compared to various gas targets at room temperature. The sensor exhibited rapid response and recovery times of 9.8 s and 4.4 s, respectively, toward triethylamine with excellent stability in variable humid environments. The sensor maintained a consistent response over 24 days, demonstrating good stability at high humidity.

Application and comparison of point-of-care devices for field evaluation of underlying health status of Guatemalan sugarcane workers.

With chronic disease prevalence on the rise globally, surveillance and monitoring are critical to improving health outcomes. Point-of-care (POC) testing can facilitate epidemiological research and enhance surveillance systems in limited resource settings, but previous research has identified bias between POC devices and laboratory testing. We compared the performance of two POC blood analyzers, the iSTAT handheld (Abbott, Princeton, NJ, USA) and the StatSensor Creatinine (Nova Biomedical, Waltham, MA, USA) to concurrent blood samples analyzed at a local laboratory that were collected from 89 agricultural workers in Guatemala. We measured creatinine and other measures of underlying health status with the POC and the lab blood samples. Pearson correlation coefficients, Bland-Altman plots, no intercept linear regression models and two-sample t-tests were used to evaluate the agreement between the POC and lab values collected across three study days and to assess differences by study day in a field setting. On average there was no observed difference between the iSTAT and lab creatinine measurements (p = 0.91), regardless of study day. Using lab creatinine as the gold standard, iSTAT creatinine results were more accurate compared to the Statsensor, which showed some bias, especially at higher values. The iSTAT had good agreement with the lab for sodium and blood urea nitrogen (BUN), but showed differences for potassium, anion gap, bicarbonate (TCO2), glucose, and hematocrit. In this tropical field setting, the research team devised a protocol to prevent the devices from overheating. In limited resource settings, POC devices carry advantages compared to traditional lab analyses, providing timely results to patients, researchers, and healthcare systems to better evaluate chronic health conditions. Technical challenges due to use of POC devices in high heat and humidity environments can be addressed using a standard protocol for transporting and operating the devices.

Ulcerative and pyogranulomatous pododermatitis due to Pseudomonas luteola infection in a domestic ferret (Mustela putorius furo): a case report with literature review of this emerging zoonotic disease in ferrets

Pseudomonas luteola (P.luteola), formerly called Chryseomonas luteola, is a strict aerobic gram-negative bacillus, 0.8 to 1.0 µm wide and 1.5 to 2.5 µm long, considered an opportunistic pathogen found ubiquitously in humid environments, both in soil and water. It sporadically causes disease in animals and immunosuppressed humans or those subjected to invasive procedures such us peritoneal dialysis or catheterization. In ferrets, this infection was first described in Spain in 2012 and since then, cases have appeared occasionally in Finland, Austria, Australia, France, the United States and also in Spain. This pathogen is considered an emerging zoonotic disease in ferrets, causing respiratory disease, panniculitis, and abscesses due to pyogranulomatous or suppurative inflammation predominantly of the pleura, lung, mediastinum, panniculus or salivary glands, frequently with lethal consequences. The clinical case of a ferret, infected by Pseudomona luteola, presenting with ulcerative suppurative pododermatitis and ipsilateral popliteal purulent lymphadenitis, is described. Together with a complete resolution of the clinical case by means of a non-invasive medical management likely due to the rapid detection, identification, and treatment of the infection.

State-of-the-Art Review: Effects of Using Cool Building Cladding Materials on Roofs

Cool roofs are roofing systems designed to reflect significant solar radiation, reducing heat absorption and subsequent cooling energy demands in buildings. This paper provides a comprehensive review of cool roof technologies, covering performance standards, material options, energy-saving potential, and hygrothermal considerations. The review examines provisions in current codes and standards, which specify minimum requirements for solar reflectance, thermal emittance, and solar reflectance index (SRI) values. These criteria often vary based on factors like roof slope, climate zone, and building type. Different cool roof materials are explored, including reflective paints and coatings that can be applied to existing roofs as cost-effective solutions. Several studies have demonstrated the energy performance benefits of cool roofs, showing significant reductions in cooling loads, indoor air temperatures, peak cooling demand, and overall cooling energy consumption compared to traditional roofs. However, hygrothermal performance must be evaluated, especially in cold climates, to optimize insulation levels and avoid moisture accumulation risks, as reduced heat absorption can alter moisture migration patterns within the building envelope. While cool roofs provide substantial energy savings in hot climates, further research is needed to validate modeling approaches against real-world studies, investigate the impact of seasonality and green spaces on cool roof efficacy and urban heat island mitigation, and explore energy-saving potential, moisture control, and condensation risks in cold and humid environments.

Flexible Multimodal Sensors Enhanced by Electrospun Lead-Free Perovskite and PVDF-HFP Composite Form-Stable Mesh Membranes for In Situ Plant Monitoring.

The pH and humidity of the crop environment are essential indicators for monitoring crop growth status. This study reports a lead-free perovskite/polyvinylidene fluoride-hexafluoropropylene composite (LPPC) to enhance the stability and reliability of in situ plant pH and humidity monitoring. The mesh composite membrane of LPPC illustrates a hydrophobic contact angle of 101.982°, a tensile strain of 800%, and an opposing surface potential of less than -184.9 mV, which ensures fast response, high sensitivity, and stability of the sensor during long-term plant monitoring. The LPPC-coated pH electrode possesses a sensitivity of -63.90 mV/pH, which provides a fast response within 5 s and is inert to environmental temperature interference. The LPPC-coated humidity sensor obtains a sensitivity of -145.7 Ω/% RH, responds in 28 s, and works well under varying light conditions. The flexible multimodal sensor coated with an LPPC membrane completed real-time in situ monitoring of soilless strawberries for 17 consecutive days. Satisfactory consistency and accuracy performance are observed. The study provides a simple solution for developing reliable, flexible wearable multiparameter sensors for in situ monitoring of multiple parameters of crop environments.

Sensitivity analysis of a Martian atmospheric column model with data from the Mars Science Laboratory

Abstract. An extensive sensitivity analysis was performed for a horizontally homogeneous and hydrostatic 1-D column model at the Mars Science Laboratory (MSL) location. Model experiments were compared with observations from the Curiosity Rover Environmental Monitoring Station humidity (REMS-H) device and ChemCam. Based on our earlier column model investigations, model surface temperature and pressure, dust optical depth (τ), and column precipitable water content (PWC) were the parameters that we investigated with our sensitivity analysis. Our analysis suggests that the most sensitive parameters for the column model temperature profile are τ and surface temperature. The initial value of PWC does not affect the temperature profile of the model, but it is the most important parameter for the humidity profile. The fixed value of τ also seems to have some effect on the humidity profile of the model. Based on our analysis, variations in surface pressure initialization are negligible for the model's temperature and almost negligible for the model's humidity predictions. The model simulations are generally in good agreement with the observations. Our additional model experiments with a different shape of the model's initial humidity profile yielded better results compared to the well-mixed assumption in the predicted water vapor volume mixing ratios at 1.6 m.

Sodium alginate/guar gum/multi-walled carbon nanotubes-based hydrophobic Joule thermal textiles for enhanced body thermal management and dehumidification

A sodium alginate (SA), guar gum, and multi-walled carbon nanotube composite solution was prepared using a simple blending method, followed by the construction of alginate/guar gum/multi-walled carbon nanotube fibers and fabrics through complexation with various metal ions (zinc, copper, calcium), featuring multiple hydrogen bonds and ionic complex structures. Specifically, the sodium alginate zinc/guar gum/multi-walled carbon nanotube (SA/GG/Zn2+/MWCNTs) composite fibers exhibited a significant Joule heat effect. By integrating with electronic components such as a temperature control switch, a wearable device capable of operating in cold and humid environments for dehumidification and warming was fabricated. The SA/GG/Zn2+/MWCNTs composite fabric demonstrated excellent hydrophobicity, with a contact angle reaching 145.4°, significantly enhancing its resistance to droplet penetration. Under a 5V voltage, the composite fabric rapidly generated Joule heat, increasing the surface temperature by 5∼7 °C (sensible heat) within just 40 s. Additionally, part of its energy (latent heat) transformed the tiny droplets adhering to the fabric's surface from liquid to gas, achieving dehumidification. This research provides an important theoretical and practical foundation for enhancing the performance and energy efficiency of personal thermal management textiles.

Design of Mineral Oil/Stearic Acid Hybrid Coatings for Reducing Hygroscopicity of Ammonium Nitrate.

Ammonium nitrate (AN) is a very promising high-energy oxidant for use in solid propellants but suffers from serious hygroscopicity. While various coating materials (e.g., surfactants) have been employed to mitigate the hygroscopicity of AN, the interaction mechanisms between AN and these coatings remain inadequately understood. Here, we report the preparation of a mineral oil/stearic acid (MO/SA) hybrid coating that significantly reduces the hygroscopicity of AN. The hygroscopicity of AN is efficiently inhibited through interactions between the NH4+ of AN molecules and the -COOH of SA molecules, resulting in the formation of a dense and hydrophobic coating. Additionally, the defects in the SA coating are compensated for by the MO film. Consequently, MO/SA@AN particles with a low mass ratio of the coating (1.35 wt %) exhibit a low hygroscopicity of 7.24% after being kept in a 90% relative humidity environment at 20 °C for 24 h, representing a 48.10% decline of the hygroscopicity. Furthermore, MO/SA@AN maintains a high rate of hygroscopicity decline, at 29.5%, even at 35 °C and 90% RH after 24 h. Additionally, the hybrid coating effectively accelerates the thermal decomposition reactions of AN. This study provides valuable insights into the development of hybrid coatings with excellent antihygroscopic properties for AN.

Humidity Diffusion Process Analysis and Life Prediction of a VSC-HVDC Control Protection Device Based on a Finite Element Simulation Method

Voltage Source Converter-based High-Voltage Direct Current Transmission (VSC-HVDC) is essential for integrating renewable energy sources and facilitating inter-regional power transmission. This study evaluates the reliability of control and protection devices within these systems, which are crucial for the stable operation of power grids. Humidity significantly affects both the operational conditions and lifespan of these devices. Previous studies, reliant on extensive full-condition fatigue testing, have lacked effective test models and detailed analyses of mechanisms. To address this gap, a humidity diffusion model was developed to comprehensively investigate moisture diffusion mechanisms. Using the insights gained, the Hallberg–Peck model was applied to predict the lifespan of these devices, quantitatively assessing how changes in humidity affect their reliability. This approach employs a stringent failure criterion, leading to a conservative predicted lifespan. This method achieved a prediction accuracy of 85.648% compared to the benchmarks in GB/T 2423.50-2012, validating the accuracy of our model and the effectiveness of our simulation technology under stringent conditions. This research provides vital theoretical data and serves as an essential tool for guiding the precise maintenance of equipment in varying environmental humidity levels.

Study of Manipulative In Situ Pore-Formation upon Polymeric Coating on Cylindrical Substrate for Sustained Drug Delivery.

Herein, the micro-porous polylactic acid coating applied on the surface of the cylindrical substrate is fabricated by a novel in situ pore-formation strategy based on the combinational effect of breath figure (BF) and vapor-induced phase separation (VIPS) processes. Under the condition of high environmental humidity, solvent pair of chloroform and dimethylformamide is employed for post-treatment onto pre-formed PLA coating to induce the pore-formation following the mechanism of BF and VIPS, respectively. A composite porous structure with both cellular-like and bi-continuous network morphologies is obtained. By tunning the experimental factors including the ratio of the solvent pair, environmental humidity, and temperature, morphological manipulation upon the pore morphology can be facilely achieved based on the control of mechanism transition between BF and VIPS. Paclitaxel is used as a model drug and loaded into the porous coating by the wicking effect of post-immersion. Coatings with different morphological features show varying drug loading and release capacities. The 28-day release test reveals dynamic release profiles between different coating samples, with the total release rate ranging from 35.70% to 79.96%. Optimal loading capacity of 19.28µg cm-2 and 28-day release rate of 35.70% are achieved for the coating with composite BF-VIPS structure. This research established a cost-efficient strategy with high flexibility in the structural manipulation concerning the construction of drug-eluting coating with the feature of manipulative drug delivery.

Machine learning-based analysis and prediction of meteorological factors and urban heatstroke diseases.

Heatstroke is a serious clinical condition caused by exposure to high temperature and high humidity environment, which leads to a rapid increase of the core temperature of the body to more than 40°C, accompanied by skin burning, consciousness disorders and other organ system damage. This study aims to analyze the effect of meteorological factors on the incidence of heatstroke using machine learning, and to construct a heatstroke forecasting model to provide reference for heatstroke prevention. The data of heatstroke incidence and meteorological factors in a city in South China from May to September 2014-2019 were analyzed in this study. The lagged effect of meteorological factors on heatstroke incidence was analyzed based on the distributed lag non-linear model, and the prediction model was constructed by using regression decision tree, random forest, gradient boosting trees, linear SVRs, LSTMs, and ARIMA algorithm. The cumulative lagged effect found that heat index, dew-point temperature, daily maximum temperature and relative humidity had the greatest influence on heatstroke. When the heat index, dew-point temperature, and daily maximum temperature exceeded certain thresholds, the risk of heatstroke was significantly increased on the same day and within the following 5 days. The lagged effect of relative humidity on the occurrence of heatstroke was different with the change of relative humidity, and both excessively high and low environmental humidity levels exhibited a longer lagged effect on the occurrence of heatstroke. With regard to the prediction model, random forest model had the best performance of 5.28 on RMSE and dropped to 3.77 after being adjusted. The incidence of heatstroke in this city is significantly correlated with heat index, heatwave, dew-point temperature, air temperature and zhongfu, among which the heat index and dew-point temperature have a significant lagged effect on heatstroke incidence. Relevant departments need to closely monitor the data of the correlated factors, and adopt heat prevention measures before the temperature peaks, calling on citizens to reduce outdoor activities.

Preparation and Performance of a Novel Polyurethane Microporous Film on Polypropylene Medical Mesh Surface

This study aims to develop a medical patch surface material featuring a microporous polyurethane (PU) membrane and to assess the material's properties and biological performance. The goal is to enhance the clinical applicability of pelvic floor repair patch materials. PU films with a microporous surface were prepared using PU prepolymer foaming technology. The films were produced by optimizing the PU prepolymer isocyanate index (R value) and the relative humidity (RH) of the foaming environment. The surface morphology of the PU microporous films was observed by scanning electron microscopy, and the chemical properties of the PU microporous films, including hydrophilicity, were analyzed using infrared spectroscopy, Raman spectroscopy, and water contact angle measurements. In vitro evaluations included testing the effects of PU microporous film extracts on the proliferation of L929 mouse fibroblasts and observing the adhesion and morphology of these fibroblasts. Additionally, the effect of the PU microporous films on RAW264.7 mouse macrophages was studied. Immune response and tissue regeneration were assessed in vivo using Sprague Dawley (SD) rats. The PU films exhibited a well-defined and uniform microporous structure when the R value of PU prepolymer=1.5 and the foaming environment RH=70%. The chemical structure of the PU microporous films was not significantly altered compared to the PU films, with a significantly lower water contact angle ([55.7±1.5]° ) compared to PU films ([69.5±1.7]° ) and polypropylene (PP) ([ 104.3±2.5]°), indicating superior hydrophilicity. The extracts from PU microporous films demonstrated good in vitro biocompatibility, promoting the proliferation of L929 mouse fibroblasts. The surface morphology of the PU microporous films facilitated fibroblast adhesion and spreading. The films also inhibited the secretion of tumor necrosis factor-α (TNF-α) and interleukin (IL)-1β by RAW264.7 macrophages while enhancing IL-10 and IL-4 secretion. Compared to 24 hours, after 72 hours of culture, the expression levels of TNF-α and IL-1β were reduced in both the PU film and PU microporous film groups and were significantly lower than those in the PP film group (P<0.05), with the most notable decreases observed in the PU microporous film group. IL-10 and IL-4 levels increased significantly in the PU microporous film group, surpassing those in the PP film group (P<0.01), with the most pronounced increase in IL-4. The PU microporous film induced mild inflammation with no significant fibrous capsule formation in vivo. After 60 days of implantation, the film partially degraded, showing extensive collagen fiber growth and muscle formation in its central region. The PU microporous film exhibits good hydrophilicity and biocompatibility. Its surface morphology enhances cell adhesion, regulates the function of RAW264.7 macrophages, and promotes tissue repair, offering new insights for the design of pelvic floor repair and reconstruction patch materials.