Core Temperature Research Articles

Design and Coupled Moisture-Thermal Transfer Simulation of Opposite Cross-Section Polyethylene Terephthalate Knitted Fabric with Hygroscopic Quick-Drying Capability.

In addition to sportswear and outdoor equipment, moisture-absorbent quick-drying fabrics are also widely used in everyday clothing and home textiles. In this study, three types of weft-knitted fabrics were designed using Coolmax fiber and polypropylene fiber. The Coolmax/PP fabric exhibits good stretchability with a strain of 180.5% and achieves a high cumulative individual transfer capability of 691.6%, with a water absorption rate of 50.2%/s. The moisture conductivity gradient presented good moisture and heat conductivity in a simulated human body temperature environment using an infrared camera. Furthermore, mathematical modeling was constructed and visual simulation analysis was conducted to explore moisture-thermal transfer behavior. The simulation results closely align with experimental data, providing insights into designing flexible and wearable quick-drying fabrics for thermal management.

Voluntary head dunking after exercise-induced hyperthermia rapidly reduces core body temperature in dogs.

To evaluate field-applicable cooling methods for treatment of exercise-induced hyperthermia in dogs. In this randomized, crossover study from June 27, 2023, to July 24, 2023, 12 working dogs exercised for 10 minutes until core body temperature reached 40.6 °C or above or ≥ 2 signs of heat stress were observed. Four different cooling protocols were evaluated: (1) neck chemical ice packs (2), (2) a wet (22 °C) neck towel, (3) wet (22 °C) axillae towels, or (4) voluntary head immersion ("dunking") into (22 °C) water. After intervention, dogs rested and were monitored for 40 minutes. The dunking protocol, which included limited water ingestion, produced the lowest mean core temperature in the initial 5 minutes after exercise, in the subsequent 35 minutes during which dogs cooled to baseline temperature and was the only protocol to prevent the initial postexercise temperature rise. All methods resulted in return to baseline temperature. Trained voluntary head dunk with limited water ingestion results in rapid cooling in field situations of exercise-induced hyperthermia in dogs with normal mental status and ability to pause panting. "Cool first, transport second" reduces morbidity and mortality of acute heat injury. When whole-body water immersion is not an option, the trained voluntary head dunk in mentally appropriate dogs prevents postexercise rise and rapidly reduces core body temperature within the first 5 minutes. Alternatively, allowing the dog to drink controlled amounts of cool water and pouring water on the dog's head may provide some benefit but warrants further study.

Effects of hypobaric hypoxia on human physiological and psychological responses in hot-humid environments

The hot-humid and hypobaric hypoxic environment hampers human physiological and psychological responses. In this study, 10 healthy participants were recruited to walk on a treadmill at 4 km/h in a hypobaric chamber under nine experimental conditions involving three air temperatures (Ta = 33, 37, and 40 °C), and three barometric pressures (PB = 96.5, 65.7, and 63.2 kPa). At 33 and 37 °C, the mean skin temperature, oral temperature, and sweat rate were not significantly affected by hypobaric hypoxia. The diastolic blood pressure, systolic blood pressure, and oxygen saturation decreased significantly, while the heart rate increased significantly under hypobaric hypoxic conditions. At 40 °C, the heart rate and diastolic blood pressure were not significantly affected by hypobaric hypoxia, while the oral temperature was significantly higher at 63.2 kPa than at 65.7 and 95.6 kPa. The remaining physiological parameters exhibited similar patterns as those at 33 and 37 °C. In conclusion, higher Ta had the most substantial effects on the cardiovascular system. Additionally, individuals should not work in environments where the Ta exceeds the body core temperature, especially at higher altitudes, as the risk of heat-related injuries could increase. At various Ta, the thermal sensation and acceptability were not significantly affected by hypobaric hypoxia, while a decrease in PB to 63.2 kPa resulted in a significant increase in tolerance, along with a notable reduction in exposure time. Therefore, this study provides valuable information concerning the physiological and psychological responses of humans exposed to working conditions similar to those tested.

Estimation of the difference between peritoneal microenvironment and core body temperature during laparoscopic surgery – a prospective observational study

Maintaining patients’ temperature during surgery is beneficial since hypothermia has been linked with perioperative complications. Laparoscopic surgery involves the insufflation of carbon dioxide (CO2) into the peritoneal cavity and has become the standard in many surgical indications since it is associated with better and faster recovery. However, the use of cold and dry CO2 insufflation can lead to perioperative hypothermia. We aimed to assess the difference between intraperitoneal and core temperatures during laparoscopic surgery and evaluate the influence of duration and CO2 insufflation volume by fitting a mixed generalized additive model. In this prospective observational single-center cohort trial, we included patients aged over 17 with American Society of Anesthesiology risk scores I to III undergoing laparoscopic surgery. Anesthesia, ventilation, and analgesia followed standard protocols, while patients received active warming using blankets and warmed fluids. Temperature data, CO2 ventilation parameters, and intraabdominal pressure were collected. We recruited 51 patients. The core temperature was maintained above 36 °C and progressively raised toward 37 °C as pneumoperitoneum time passed. In contrast, the intraperitoneal temperature decreased, thus creating a widening difference from 0.4 [25th–75th percentile: 0.2–0.8] °C at the beginning to 2.3 [2.1–2.3] °C after 240 min. Pneumoperitoneum duration and CO2 insufflation volume significantly increased this temperature difference (P < 0.001 for both parameters). Core vs. intraperitoneal temperature difference increased linearly by 0.01 T °C per minute of pneumoperitoneum time up to 120 min and then 0.05 T °C per minute. Each insufflated liter per unit of time, i.e. every 10 min, increased the temperature difference by approximately 0.009 T °C. Our findings highlight the impact of pneumoperitoneum duration and CO2 insufflation volume on the difference between core and intraperitoneal temperatures. Implementing adequate external warming during laparoscopic surgery effectively maintains core temperature despite the use of dry and unwarmed CO2 gases, but peritoneal hypothermia remains a concern, suggesting the importance of further research into regional effects.Trial registration: Clinicaltrials.gov: NCT04294758.

Reliability of Wearable Technology to Monitor Core Temperature Among Helicopter-Based EMS Crews.

Excessive heat stress led to more than 400 deaths in the United States from 2011 to 2021. Common methods for heat injury prevention revolve around measurements of the environment and fail to account for the unique individual response to stressors. An observational approach was utilized with nine helicopter-based emergency medical services personnel during emergency flights to compare core temperature readings obtained from an ingestible temperature monitoring pill and the estimated core temperature reading of the Slate Safety Band V2 wearable device. Comparison of data was conducted within Microsoft Excel programming to determine the mean square error (MSE), root mean square error (RMSE), mean absolute error (MAE), mean biased error (MBE), and Bland-Altman plot development. A significant bias (t = 17.58, p < .001) toward the Slate Safety device reading higher with an average difference of -0.48°C (-0.86°F) was found, meaning the average temperature reading is 0.48°C (-0.86°F) higher with the Slate Safety device. A significant correlation of .26 (p < .001) was noted between the ingestible pill and the wearable device with a 95% confidence interval of 0.23 to 0.29. Aggregate core temperature data demonstrated an MSE of 0.43, an RMSE of 0.65, an MAE of 0.54, and an MBE of -0.48. The ability to monitor the physiological parameters of a worker remotely adds safety tools relative to the risks of heat stress. The slightly higher reading associated with the Slate Safety wearable device provides an added safety margin to protect our workers.

Heat Attainment and Retention in Surfers with and without a Land-Based Warm-Up and Accompanying Passive Heat Retention.

Surfing is a growing, high-participation recreational and competitive activity. It is relatively unique, being performed on, in, and through water with a range of temperatures. In other sports, warm-up and heat retention have proved useful at augmenting performance and ameliorating injury risk. Little work has been carried out examining this in surfing. The purpose of this work was to measure thermal profiles in surfers with and without warm-up and passive heat retention, and secondarily to assess any potential influence on free surfing. A repeated measures pre- and post- design was adopted whereby participants surfed in an artificial wave pool following an active warm-up combined with passive heat retention (experimental condition) and after no warm-up (control). Core body temperature was measured both occasions. Our results showed increases in core body temperature were greater for the experimental condition versus control (p = 0.006), and a time effect exists (p < 0.001)-in particular, a warm-up effect in the water itself was shown in both groups, possibly due to further activity (e.g., paddling) and wetsuit properties. Finally, performance trended to being superior following warm-up. We conclude that body warmth in surfers may be facilitated by an active warm-up and passive heat retention. In free surfing, this is associated with a trend towards better performance; it may also reduce injury risk.

Upper- vs. Whole-Body Cooling During Exercise with Thermal Protective Clothing in the Heat.

INTRODUCTION: Firefighters operating in hot environments face challenges from protective garments that restrict heat dissipation, resulting in increased core temperature, thermal discomfort, and performance decline. Cooling vests represent a viable solution. The study aim was to compare effectiveness of the same amount of cooling power to the upper body (UB) or whole body (WB) in alleviating thermoregulatory and physiological stress, enhancing cognitive function, and reducing ratings of thermal discomfort and exertion, during 60 min of exercise in a hot environment (40°C, 40% relative humidity) while wearing firefighter turnout gear.METHODS: Eight healthy individuals (27.5 ± 3 y) participated in three conditions with either no cooling (Control) or active cooling with a liquid perfused shirt (UB cooling), or with a liquid perfused shirt and pants (WB cooling). In each trial, subjects performed three sets of 15 min of stepping (20 steps ⋅ min-1) and 5 min of rest.RESULTS: Both cooling strategies were beneficial compared to having no cooling at all. Subjects could only complete two exercise bouts during Control, but they completed all three bouts with active cooling. WB cooling provided an advantage over UB cooling for core and skin temperature, and thermal comfort and sensation. The advantage in minimizing the increase in core temperature was only evident during the third exercise bout.DISCUSSION: Active cooling is advantageous under these conditions. WB cooling provided some benefits vs UB cooling during heavy intensity exercise; however, it is uncertain whether these benefits would be observed during light-to-moderate exercise, which more likely reflects an actual firefighting scenario.Mansouri F, Talebian Nia M, Villar R, Cornish SM, Giesbrecht GG. Upper- vs. whole-body cooling during exercise with thermal protective clothing in the heat. Aerosp Med Hum Perform. 2024; 95(9):659-666.

Effects of firefighters’ protective gloves on physiological responses, psychological responses, and manual performance in a cold environment

This study aimed to investigate the effects of firefighters' protective gloves on physiological responses, psychological responses, and manual performance in a cold environment through human trials. Twelve participants wearing firefighter protective equipment were exposed to a 16 °C environment, while their hands were exposed to a small chamber of 0 °C with (FPG) and without (CON) firefighting protective gloves. During the trials, physiological responses (core temperature (Tc), the mean skin temperature (Tsk), and heart rate (HR)), psychological responses (thermal sensation vote (TSV) and pain sensation vote (PSV)), and manual performance (handgrip strength, manual dexterity, maximum finger flexion, and tactile sensitivity)) were obtained. The results indicated a significant difference (p < 0.05) between FPG and CON regarding Tsk. Furthermore, pain sensation occurred when the mean skin temperature of the hand was between 15 °C and 20 °C. Gloves significantly (p < 0.05) reduced handgrip strength, manual dexterity, and tactile sensitivity in the cold exposure. This study provides fundamental knowledge for cold strain assessment and high-performance protective glove development with the potential to improve firefighters’ safety and health.

Efficiency of natural and forced convection systems in cooking ham: Industrial scale validation

AbstractThis study evaluated the efficacy of cooking processes in natural and forced convection systems, for ensuring microbiological safety in industrial‐scale ham production. The cold point of the tanks was determined by measuring the water temperature every 2 min, with a maximum variation of 1.4°C between different regions of the tanks. The calculation of the lethal value (Fcal) was carried out using Enterococcus faecalis as the target microorganism due to its high resistance to heat treatment. The cooking temperature was measured at the geometric center of the ham and, in both convection systems, it reached the Fref value (23.6 min), necessary to achieve a reduction of 8 log (8 D), with Fcal of 45.7 and 45 min of cooking in the natural and forced convection systems. Both convection systems achieved microbial reductions exceeding 15‐log cycles (15 D), surpassing regulatory requirements despite occasional core temperatures below standard thresholds. In both systems (natural and forced), the cold spot was found on the left side, at a lower height, and toward the front of the tank. After heat treatment, no microorganisms were detected in the ham cooked in natural or forced convection systems. Both systems (natural and forced convection) proved viable at an industrial scale, provided that appropriate cooking protocols are followed.Practical ApplicationsThe practical applications of this study are significant for the food industry and regulatory bodies involved in food safety. These include quality assurance in ham production, food safety compliance, process optimization, risk mitigation, and guidance for industrial practices. Overall, this study has practical implications for improving food safety, quality control, and production efficiency in the ham industry. It fills a gap in validation studies on industrial‐scale ham cooking, providing valuable information for industry stakeholders and regulatory bodies alike.

The impact of asteroseismically calibrated internal mixing on nucleosynthetic wind yields of massive stars

Context. Asteroseismology gives us the opportunity to look inside stars and determine their internal properties, such as the radius and mass of the convective core. Based on these observations, estimations can be made for the amount of the convective boundary mixing and envelope mixing of such stars and for the shape of the mixing profile in the envelope. However, these results are not typically included in stellar evolution models. Aims. We aim to investigate the impact of varying convective boundary mixing and envelope mixing in a range based on asteroseismic modelling in stellar models up to the core collapse, both for the stellar structure and for the nucleosynthetic yields. In this first study, we focus on the pre-explosive evolution and we evolved the models to the final phases of carbon burning. This set of models is the first to implement envelope mixing based on internal gravity waves for the entire evolution of the star. Methods. We used the MESA stellar evolution code to simulate stellar models with an initial mass of 20 M⊙ from zero-age main sequence up to a central core temperature of 109 K, which corresponds to the final phases of carbon burning. We varied the convective boundary mixing, implemented as ‘step-overshoot’, with the overshoot parameter (αov) in the range 0.05−0.4. We varied the amount of envelope mixing (log(Denv/cm2 s−1)) in the range 0−6 with a mixing profile based on internal gravity waves. To study the nucleosynthesis taking place in these stars in great detail, we used a large nuclear network of 212 isotopes from 1H to 66Zn. Results. Enhanced mixing according to the asteroseismology of main-sequence stars, both at the convective core boundary and in the envelope, has significant effects on the nucleosynthetic wind yields. This is especially the case for 36Cl and 41Ca, whose wind yields increase by ten orders of magnitude compared to those of the models without enhance envelope mixing. Our evolutionary models beyond the main sequence diverge in yields from models based on rotational mixing, having longer helium-burning lifetimes and lighter helium-depleted cores. Conclusions. We find that the asteroseismic ranges of internal mixing calibrated from core hydrogen-burning stars lead to similar wind yields as those resulting from the theory of rotational mixing. Adopting the seismic mixing levels beyond the main sequence, we find earlier transitions to radiative carbon burning compared to models based on rotational mixing because they have lower envelope mixing in that phase. This influences the compactness and the occurrence of shell mergers, which may affect the supernova properties and explosive nucleosynthesis.

The forensic significance of core temperature in identifying primary and secondary hypothermia as a cause of death: A pilot study on Wistar rats

IntroductionHypothermia is defined as a body core temperature below 35 °C and can be caused by internal or external stress. Primary hypothermia is caused by excessive exposure to low environmental temperature without any medical conditions prior to that. Secondary hypothermia is caused by alteration in thermoregulation by disease, trauma, surgery, drugs, or infections. The aim of the research is to investigate core temperature values in rats subjected to specific water temperatures at five different time points. It focuses on distinguishing between primary and secondary hypothermia in these rats. MethodsThe total 21 Wistar rats were divided into three experimental groups as: Control group rats exposed only to hypothermic condition (n = 7); Alcohol + hypothermia (n = 7); and Benzodiazepines + hypothermia (n = 7). The temperature spots analyzed in the study were: normal core temperature, core temperature during injection of 0,3 ketamine, temperature of immersion and the temperature at the onset of hypothermia and temperature at the time of death. ResultsIn our study the comparative analysis of body temperatures at various time points following submersion in water revealed significant differences among the study groups treated with either alcohol or benzodiazepines and the control group. Notable differences were observed in baseline temperature, post-anesthesia induction temperature, and immediate post-submersion temperature. Specifically, significant differences were discovered among the alcohol and benzodiazepine groups (p < 0.001) and ranging from the alcohol and control groups (p < 0.001). The analysis of survival times following induced hypothermia revealed a statistically significant difference among the three experimental groups (p = 0.04), though subsequent post-hoc comparisons did not demonstrate significant differences in mean survival times. ConclusionThere is a difference in survival time between primary and secondary hypothermia groups, depending on consumption and intoxication with alcohol or benzodiazepines. The analysis of survival times following induced hypothermia showed a statistically significant difference among the groups.

Accuracy, precision and diagnostic accuracy of oral thermometry in pediatric patients

PurposeTo determine the accuracy and precision of oral thermometry in pediatric patients, along with its sensitivity and specificity for detecting fever and hypothermia, with rectal thermometry as reference standard. Design and methodsThis method-comparison study enrolled patients aged between 6 and 17 years, admitted to the surgical ward during a 21-month period. KD-2150 and IVAC Temp Plus II were used for oral and rectal temperature measurements respectively. Fever and hypothermia were defined as core temperature ≥38.0 °C and ≤ 35.9 °C respectively. Accuracy and precision of oral thermometry were determined by the Bland-Altman method. Sensitivity, specificity, positive and negative predictive value, and correct classification of oral temperature cutoffs for detecting fever and hypothermia were calculated. ResultsBased on power analysis, 100 pediatric patients were enrolled. The mean difference between oral and rectal temperatures was −0.34 °C, with 95 % limits of agreement ranging between −0.52 and −0.16. Sensitivity and specificity of oral thermometry for detecting fever were 0.50 and 1.0 respectively; its sensitivity and specificity for detecting hypothermia were 1.0 and 0.88 respectively. The oral temperature value of 37.6 °C provided excellent sensitivity for detecting fever, while the value of 35.7 °C provided optimal sensitivity and specificity for detecting hypothermia. ConclusionsOral thermometry had low sensitivity for detecting fever and suboptimal specificity for detecting hypothermia; thus, temperature values <38.0 °C and <36.0 °C cannot exclude fever and confirm hypothermia respectively with high certainty. Practice implicationsDiagnostic accuracy of oral thermometry can be improved by the use of oral temperature thresholds <38.0 °C for detecting fever and <35.9 °C for detecting hypothermia.

Rebound Hyperthermia in Exertional Heat Stroke.

Exertional heat stroke (EHS) is a life-threatening condition requiring rapid reversal of hyperthermia to prevent poor health outcomes. Current treatment protocols aim for a cooling rate of 0.15 C/min using various modalities. This case report details a 22-year-old male who, despite initial successful cooling measures, experienced rebound hyperthermia, necessitating the use of endovascular cooling (EVC). The patient collapsed during a 19.3 km (12-mile) ruck march in Fort Moore, Georgia, with an initial core temperature of 41.6ºC. Conventional cooling methods, including ice sheets and chilled intravenous saline, adequately cooled the patient to target temperatures; however, discontinuation of cooling methods resulted in rebound hyperthermia. Endovascular cooling was eventually initiated, resulting in euthermia after 36 hours of continued use. During his hospital admission, the patient was evaluated thoroughly for underlying etiologies contributing to his rebound hyperthermia. This workup did not yield any concerning pathology, except for bilateral foot cellulitis noted on physical examination, which was subsequently managed with antibiotics. Despite initial complications, the patient recovered within 5 days and returned to duty after 2 months. Several case reports have been published regarding the use of EVC in the management of EHS. These reports, however, describe its use in initial management of EHS or in cases where hyperthermia was refractory to other conventional cooling methods. To our knowledge, this is the first report of its kind highlighting its successful implementation in rebound hyperthermia. Early recognition and initiation of cooling measures are critical in EHS cases. Future directions include developing EHS-specific EVC protocols for patients experiencing refractory or rebound hyperthermia.

Body temperature-triggered adhesive ionic conductive hydrogels for bioelectrical signal monitoring

Bioadhesive ion-conductive hydrogels are essential in bioelectrical signal monitoring. However, highly adhesive hydrogels may cause discomfort, such as skin redness and pain when peeled off, which hinders their application. Here, we design a body temperature-triggered adhesive ionic conductive hydrogel based on biocompatible polyacrylamide (PAAM), gelatin, and sodium alginate (SA). Due to the temperature sensitivity of gelatin, the adhesion of the developed PAAM/gelatin/SA (PGS) hydrogel is rapidly enhanced upon exposure to human body temperature, and it decreases quickly within a short period (10 s) after cooling, thus enabling painless removal. At the same time, the hydrogel exhibits a Young’s modulus (∼265 kPa) similar to that of skin tissue and achieves a conformal contact to the skin. Benefiting from the low electrode-epidermal impedance, the developed hydrogel has a decent signal-to-noise ratio of about 25 dB, allowing high-fidelity recording of various bioelectrical signals and accurate recognition of movements. The temperature-triggered adhesion-changing conductive hydrogel presented in this work shows great potential for biomedical applications.

Assessing core body temperature in a cool marathon using two pill ingestion strategies

Abstract Objectives The purpose was to directly assess in-competition thermoregulatory responses in recreational runners during a city marathon conducted in cool, ambient conditions using a two-pill ingestion strategy. Methods Thirty-two recreational runners (age: 38.7 ± 10.2 years, mass: 73.9 ± 11.0 kg, height: 177 ± 8 cm) were invited to participate in this study. Core temperature was continuously assessed using telemetric ingestible pills. Each runner swallowed two pills: the first pill (Pill 1) 11 h:47 min ± 1 h:01 min pre-race (before overnight sleep) and the second (Pill 2) 2 h:35 min ± 0 h:54 min pre-race (on wakening). Results Pre-race core temperature for Pill 1 was significantly different from Pill 2, with values of 37.4 ± 0.4 °C and 37.1 ± 0.6 °C, respectively (p=0.006). The mean core temperature during the race was higher for Pill 1 compared to Pill 2 (38.5 ± 0.5 °C and 37.8 ± 1.0 °C, respectively; p&lt;0.001). Peak core temperature was higher for Pill 1 compared to Pill 2 (39.1 ± 0.5 °C and 38.8 ± 0.5 °C, respectively; p=0.03). Post-race core temperature was higher for Pill 1 compared to Pill 2 (38.8 ± 0.7 °C and 38.1 ± 1.3 °C, respectively; p=0.02). Conclusions The timing of pill ingestion significantly impacted core temperature and hence timing of pill ingestion should be standardised (5 h:30 min–7 h prior to measurement). Despite the relatively cool ambient conditions during the race, a significant number of runners achieved a high core body temperature (≥39 °C), which was not accompanied by any signs of heat illness.

Impact of tent shade on heat exposures and simulated heat strain for people experiencing homelessness.

Concurrent increases in homelessness and heat intensity, duration, and frequency translate to an urban heat risk trap for the unsheltered population. Homelessness is both a driver and consequence of poor health, co-creating distinct geographies with various risk factors that exacerbate heat vulnerability. We tested the efficacy of different tent shadings over identical tents often observed in the Phoenix area (white bedsheet, mylar, tarp, and aluminum foil) and compared them to a control tent (uncovered) and ambient conditions. We monitored all meteorological variables at all six locations, notably Mean Radiant Temperature (MRT). The in-tent microclimate variability was applied to complete statistical and physiological modeling including substance use on heat strain. Findings indicate that tent shadings resulted in significantly lower in-tent MRT during the day (p < 0.05), but exacerbated in-tent thermal risk during the night compared to the control tent and ambient conditions. Furthermore, we found evidence that the temperature metric matters, and using only either MRT or air temperature (Tair) to assess "heat" could lead to inconsistent conclusions about in-tent microclimate. Interactions between shade types and time significantly amplified in-tent thermal risk. Physiological modeling indicates a higher risk of heat strain (core temperature beyond 40˚C) for people using substances. Decision makers should promote testing different heat intervening strategies toward realizing effective means of protecting human life and preventing heat illnesses. This study illuminates the need for an interdisciplinary approach to studying tents as shelters that considers the total heat load with heat strain modeling.

Hysteresis-Free Temperature Sensing with Printable Electronic Skins Made of Liquid Polyisoprene/CNTs.

Developing an electronic skin (e-skin) is becoming popular due to its capability to mimic human skin's ability to detect various stimuli. Mostly, such skins are tactile-based sensors. However, the exploration of nontactile-based sensing capability in the e-skin is still in a nascent stage. Herein, we report an approach toward developing electrical hysteresis- and cross-interference-free nontactile e-skin using liquid polyisoprene with an ultralow concentration of multiwalled carbon nanotubes (ϕ = 0.006 volume fraction) by leveraging the stencil printing technique. The impact of cross-linking the samples was studied. Uncross-linked samples demonstrated higher electrical conductivity than the cross-linked samples. A coarse-grained phenomenological model with molecular dynamics simulation was utilized to investigate filler network formation and percolation that dictate the conductivity of uncross-linked and cross-linked samples. Simulation studies supported the fidelity of the experimental findings. The uncross-linked e-skin demonstrated a higher temperature sensitivity (-1.103%/°C) than the cross-linked e-skin (-0.320%/°C) in the thermal conduction mode. Despite the superior sensitivity of the uncross-linked e-skin, the cross-linked systems demonstrated superior cyclic stability (35 thermal cycles), ensuring reliable sensor readings over extended usage. Judicious choice of encapsulant warranted the cross-linked e-skin sensor to nullify the impact of moisture on signal output, thereby providing cross-interference-free results. The optimized e-skin sample retained a similar thermal sensitivity even when used in the nontactile mode. From the application purview, the utility of the developed sensor was tested successfully for nontactile sensing of human body temperature. Additionally, the sensor was utilized to determine the respiratory profile by integrating the developed sensor into a wearable mask. This study advances nontactile e-skin-based sensing technology and opens new avenues for creating wearable and IoT devices for healthcare and human-machine interactions.

Experimental and numerical investigation on the effect of ease allowance of clothing on thermal comfort

The heat transfer within the microclimate of clothing directly affects the thermal sensation of the human body, holding significant implications for both heat dissipation and cold protection. To investigate the variations in the heat transfer performance of the microclimate under the clothing influenced by distinct air gap thicknesses and diverse body postures, twelve female subjects participated in experiments wearing T-shirts with various ease allowances, conducting tasks in both sitting and standing positions within a climate chamber set at 20 °C and 50 % RH. Physiological parameters and subjective evaluations of comfort were recorded. Additionally, we constructed a three-dimensional model of the air gap featuring realistic morphology for numerical simulations of microclimatic heat transfer in a standing posture. The experimental results indicate that air gap thickness significantly impacts core temperature, mean skin temperature, local skin temperature, and thermal sensation. While postural differences did not show statistical significance, temperatures and thermal sensations were generally higher in the sitting position. Based on the results of numerical simulation, under this environmental condition, approximately 27 % of heat transfer was through radiation, with both the percentage of radiative heat transfer and the overall heat flux increasing with greater ease allowance. Furthermore, airflow under the clothing became more disorganized at thicker air layers, primarily concentrating in folds, hems, and sides of the body. This study provides a theoretical support for the workwear design and similar clothing and helps to reduce energy consumption in office environments.

Effects of High-Speed Shearing Treatment on the Physical Properties of Carbohydrate-Binder Mixture during Gelatinization for Preparing Freeze-Dried Soup Products.

Modernization has led to a large convenience food market, and the demand for freeze-dried (FD) soup products is increasing in the Republic of Korea. FD soup products are easy to eat without cooking and can be stored for long periods. However, it is often difficult to ensure sensory satisfaction after rehydration of FD soup products; in particular, the ingredients are not evenly dispersed. Therefore, a stable dispersion or reconstitution of the FD soup products is required after rehydration. Here, the effects of high-speed shearing homogenization on the physical properties of a carbohydrate-binder mixture comprising maltodextrin, potato starch, and rice flour were investigated during hydrothermal gelatinization. To find a suitable treatment condition, different homogenization eras, speeds, and concentrations of the binder mixture were considered; in particular, the homogenization eras were set by considering the hydrothermal property of the binder mixture profiled using differential scanning calorimetry. The viscosity of the binder mixture and the compression strength and microstructure of the FD binder block, including the dispersion stability after rehydration, were evaluated. The quality of the FD binder block was improved by homogenization above 5000 rpm when the core temperature of the binder mixture reached approximately To at 14.5-21.8% concentrations. The improved FD binder block exhibited a fine surface and tiny porous microstructure compared with the control (with continuous agitation at 250 rpm). The control block was divided into two phases, whereas the improved block maintained the initial dispersion stability at 50 °C for 1 h. These results are expected to be referenced for the purpose of improving the quality of the FD soup products.

Head and neck cooling enhance exercise tolerance in individuals with multiple sclerosis

BackgroundIndividuals with Multiple Sclerosis (MS) experience impairments in heat dissipation, compromising core temperature regulation during exercise. ObjectiveTo examine the efficacy of combined head-and-neck cooling as administered via a commercially available cooling cap and neck wrap in mitigating increases in core temperature during exercise. MethodsOn separate days, ten (7 females) adults (46.1 ± 11.6 years) with relapsing-remitting MS performed semi-recumbent cycling consisting of an incremental exercise bout to volitional fatigue in a temperate environment (23 °C, 50 % relative humidity) while undergoing head-and-neck cooling using a cooling cap and neck wrap maintained at 10 °C (COLD) or 24–26 °C (NEUTRAL). Prior to and following a 30-minute post-exercise recovery, functional capacity was assessed by a battery of tests consisting of a 2-minute walk test, Timed 25-Foot Walk test, sit-to-stand test, and Berg Balance Scale. Core (ingestible pill) and skin temperatures were recorded continuously. The level of fatigue was measured with questionnaires. ResultsThe duration of the incremental exercise test increased with the application of COLD (28.4 ± 5.1 min) versus NEUTRAL water (vs 20.8 ± 5.1 min) (p = 0.001) and was paralleled by a significant reduction in body temperatures (∼1 °C, p < 0.05). The distance covered during the 2-min walk test performed after the incremental exercise test increased with the COLD (176.5 ± 0.6 m), relative to the NEUTRAL condition (147.7 ± 43.5 m) (p = 0.01). Fatigue levels did not change between conditions. ConclusionWe show that head-and-neck cooling with cold water effectively enhances exercise tolerance and mitigates increases in core temperature during exercise in individuals with MS.