Lower Skin Temperature Research Articles

Exploring the Correlation of Physiological Stress Signals with Student Exam Performance: A Preliminary Study.

Stress responses in real-world settings are less studied compared to controlled laboratory environments, limiting our understanding of their impact on cognitive performance. This study investigates the relationship between physiological stress signals and academic performance using an open-access dataset of 10 students assessed across three exam sessions (Midterm 1, Midterm 2, and Final Exam). Physiological measures, including electrodermal activity (EDA), heart rate (HR), and skin surface temperature (TEMP), along with exam grades, were analyzed using traditional hypothesis testing, bootstrap method, correlation analysis, and regression tree modeling. To address the small sample size, we validated traditional hypothesis test results with the bootstrap method, and both approaches were compatible. Hypothesis testing revealed no significant differences in physiological measures across exam sessions, supporting the null hypothesis. Grades differed significantly between the final exam and both midterms (p < 0.05). Stress fluctuations were also analyzed across three periods (beginning, middle, and end) for each exam, revealing temporal response variations. Correlation analysis showed a moderate negative relationship between EDA and HR (r = -0.504, p < 0.01) and a weak positive relationship between EDA and TEMP (r = 0.417, p < 0.05), both intensifying during the final exam. Regression analysis explained 78% of the variance in grades (R2 = 0.78), with regression tree modeling identifying lower skin temperature (< 28°C) and higher EDA (≥ 0.19) as predictors of poorer performance. These findings underscore the interplay between physiological stress responses and academic outcomes, emphasizing the need for further research and interventions to support student success.

Analysis of factors affecting early necrosis of the affected finger after surgery in patients with reimplantation of severed fingers.

The study aimed to investigate the factors associated with early necrosis of the finger after reimplantation of broken fingers. Sixty-seven cases of reimplantation of severed fingers in our hospital between January 2023 and December 2023 were retrospectively analyzed. All patients underwent reimplantation of severed fingers and were divided into early necrosis group and non-necrosis group according to the presence or absence of early necrosis of the finger body 7 days after surgery. The relevant data of the 2 groups were collected, and the statistically significant items were screened by univariate analysis, and then by multifactorial logistic regression analysis to determine the high-risk factors for early necrosis after reimplantation of the severed finger. Among 67 patients, 13 cases showed early postoperative necrosis, with a necrosis rate of 19.40% (13/67). The difference between the 2 groups was significant (P < .05) in the comparison of smoking history, finger type (little finger), preoperative ischemic duration, vasospasm, type of injury (crush injury), postoperative infection, and low skin temperature. Multifactorial analysis showed that smoking history (OR = 7.255, 95% CI: 1.767-29.782), little finger (OR = 7.040, 95% CI: 1.897-26.130), preoperative ischemia ≥ 8 hours (OR = 15.714, 95% CI: 3.095-79.798), vasospasm (OR = 5.850, 95% CI: 1.563-21.894), crush injury (OR = 5.667, 95% CI: 1.393-23.059), postoperative infection (OR = 5.600, 95% CI: 1.544-20.312), and postoperative hypothermia of the skin (OR = 7.096, 95% CI: 1.872-26.906) were the necrotic post-replantation necrosis after amputation of the finger high-risk factors (OR > 1, P < .05). The risk of early necrosis of the affected finger after reimplantation of an amputated finger is closely related to smoking history, pinky size, preoperative ischemic time of more than 8 hours, vasospasm, crush injuries, postoperative infections, and postoperative hypothermic skin temperature. Preventive measures need to be taken in advance to reduce the risk of necrosis in the affected finger.

The contribution of cutaneous thermal signals to bodily self-awareness

Thermosensory signals may contribute to the sense of body ownership, but their role remains highly debated. We test this assumption within the framework of pathological body ownership, hypothesising that skin temperature and thermoception differ between right-hemisphere stroke patients with and without Disturbed Sensation of Ownership (DSO) for the contralesional plegic upper limb. Patients with DSO exhibit lower basal hand temperatures bilaterally and impaired perception of cold and warm stimuli. Lesion mapping reveals associations in the right Rolandic Operculum and Insula, with these regions linked to lower skin temperature located posterior to those associated with thermoception deficits. Disconnections in bilateral parietal regions are associated with lower hand temperature, while disconnections in a right-lateralized thalamus-parietal hub correlate with thermoception deficits. We discuss the theoretical implications of these findings in the context of the ongoing debate on the role of homeostatic signals in shaping a coherent sense of body ownership.

Investigating the potential of geothermal heat pump and precision air supply system for heat stress abatement in dairy cattle barns.

Maintaining an optimal indoor thermal environment is crucial for enhancing the welfare and productivity of livestock in intensive breeding farms. This paper investigated the application of a combined geothermal heat pump with a precision air supply (GHP-PAS) system for cooling dairy cows on a dairy farm. The effectiveness of the GHP-PAS system in mitigating heat stress in lactating dairy cattle, along with its energy performance and local cooling efficiency in the free stalls were evaluated. A total of 140 multiparous lactating Holstein cows was tested in two groups. One group was housed in a barn equipped with a GHP-PAS system (GP barn, n=70), and the other was housed in a barn with a conventional fan-sprinkling system (FS barn, n=70). Results showed that the ambient temperature of both GP and FS barns were lower than that outside the barn (P<0.05), with no significant difference between the GP and FS barns (P>0.05). Compared to cows in the FS barn, those in the GP barn exhibited lower skin temperature, rectal temperature, and respiratory rate (P<0.05). The mean temperature difference between outflow and inflow water was 2.56°C of the GHP unit. The average energy efficiency ratios (EER) of the GHP unit and the GHP-PAS system were 5.03 and 2.92, respectively. The daily average electricity consumption was 20.4±1.0 kWh. The field test results indicated that the airflow from a single nozzle of the GHP-PAS system effectively covered a stall space with an average width of 1.84m at a cow reclining height of 0.5m, with an average air velocity of 1m/s. The per-cow hourly electricity consumption for cooling was 2.04 kWh for the GHP-PAS system and 0.36 kWh for the FS system, highlighting that the GHP-PAS system is approximately 5.6 times more energy-intensive than the FS system. In conclusion, the GHP-PAS system showed the potential for alleviating heat stress in dairy cows. Further research is needed to enhance the energy efficiency and cooling effectiveness of the current GHP-PAS system.

Cooling Effectiveness of the Sustainable Cooling Solution for Cattle: Case Study in Poland

Recently, the dairy sector has been ever more affected by global warming. This study aimed to test a novel conductive cooling system for cattle that was successfully implemented and evaluated under summer thermally challenging weather conditions in Poland. The system consists mainly of the chiller, tank, and chilled water-driven mattress, designed to prioritize animal well-being. The experimental evaluation was carried out on three Friesian dry cows, housed on different types of bedding—commercial water mattress, straw, and cooling water mattress—and supplied with water at 10 °C (day) and 16 °C (night). The cooling water mattress’ surface temperature was twice as low as that of the commercial water mattress. The animal’s thermal comfort was assessed with physiological and behavioral reactions. The cooling effect on animals’ bodies was demonstrated with a lower reticulorumen temperature of the cooled cow (p &lt; 0.05) than the reference ones. The local effect of cooling was proved with an 8 °C-lower skin temperature after the cow’s resting period. The presented study opens a new research direction toward dairy cattle’s welfare, sustainability, and the food–energy–water nexus, based on potential energy and water savings.

Modeling Sensor-based Vigilance Decrement in the Healthcare Environment

Vigilance refers to an individual’s ability to maintain attention over time. Vigilance decrement is particularly concerning in clinical environments where shift work and long working hours are common. This study identifies significant factors and indicators for predicting and monitoring individuals’ vigilance decrement. We enrolled 11 participants and measured their vigilance levels by recording their reaction times while completing the Psychomotor Vigilance Test. Additionally, we measured participants’ physiological responses and collected their sleep deprivation data, demographic information, and self-reported anxiety levels. Using repeated-measures correlation analysis, we found that decreased vigilance levels, indicated by longer reaction times, were associated with higher electrodermal activity ( p &lt; .01), lower skin temperature ( p &lt; .001), shorter fixation durations ( p &lt; .05), and increased saccade frequency ( p &lt; .05). Moreover, sleep deprivation significantly affected vigilance decrement ( p &lt; .001). Our findings provide the potential to develop a predictive model of vigilance decrements using physiological signals collected from non-intrusive devices, as an alternative to current behavior-based methods.

The effect of a combined cooling intervention on cognitive function in the heat during an intermittent running protocol.

Despite optimal cognitive function being essential for performance, there is a lack of research on the effectiveness of combined cooling interventions on team sport athlete's cognitive function when exercising in the heat. In a randomised, crossover design, 12 unacclimatised men (age: 22.3±3.0years, body mass: 73.4±5.1kg, height: 181.0±5.3cm and max: 51.2±9.5mL/kg/min) participated in a control (CON) and combined cooling trial (ice slurry and ice collar; COOL). A battery of cognitive tests were completed prior to, during (at half-time) and following a 90-min intermittent running protocol in the heat (33°C, 50% relative humidity (RH)). Perceptual and physiological measures were taken throughout the protocol. In CON, response times were quicker on the Stroop task complex level (p=0.002) and the visual search test complex level at full-time (p=0.014) compared to COOL. During COOL, response times were quicker at half-time on the Stroop task complex level (p=0.024) compared to CON. Lower rectal temperatures were seen during COOL (CON: 37.44±0.65°C and COOL: 37.28±0.68°C) as well as lower skin, neck and forehead temperatures (main effect of trial, all p<0.05). Lower ratings of thermal sensation and perceived exertion and enhanced thermal comfort were recorded during COOL (main effect of trial, all p<0.05). Whilst minimal differences in cognitive function were found when using the combined cooling intervention, the findings highlight a practical and effective strategy to improving many physiological and perceptual responses to intermittent exercise in the heat.

COMPARATIVE EVALUATION OF THE ADAPTIVE RESPONSES OF YANKASA AND SUDAN FAT-TAILED SHEEP IN THE TROPICAL HOT-DRY SEASON

The aim of the study was to comparatively evaluate the variation in physiological parameters of Yankasa (n=10) and recently introduced, Sudan Fat-tailed (n=10) sheep during the peak of the hot-dry season in the Guinea Savannah climate. Results revealed that the rectal, skin, eye and hair temperatures, as well as respiratory and pulse rate were significantly higher in the afternoon as compared with the morning and evening hours in both breeds. The Sudan Fat-tailed exhibited lower (P &lt;0.05) skin and hair temperatures in the morning, while in the afternoon hours, they had higher (P &lt; 0.05) eye temperature and heart rate compared with Yankasa sheep. There was no significant breed difference in respiratory rate and rectal temperature. It was concluded that although both breeds of sheep showed some variation in physiological response to the heat stress during the peak of the hot- dry season, they are equally adapted to the peak of the heat stress in the Guinea Savannah climate. However, the adaptive responses of Sudan Fat-tailed to other seasons need to be evaluated.

Cooler break areas: Reducing heat stress among construction workers in Japan

This study explores the break environment conditions provided to construction workers in hot and humid climates and assesses the impact of the thermal conditions in rest areas on the physiological and psychological responses of the workers. It was conducted during summer in Japan with 26 male rebar workers across five construction sites by monitoring variables such as ambient temperature, humidity, step count, pulse rate, blood pressure, forehead skin temperature, and fatigue level. Workers worked for approximately 8–9 h per day, with scheduled 15–30-min short breaks at 10:00 and 15:00, in addition to a 1-h break at lunchtime. While the work sites exhibited temperatures ranging from 30.0 to 38.4 °C and relative humidity between 47.0 and 87.2 %, the thermal conditions in the rest areas varied, with temperatures from 26.9 to 35.8 °C and relative humidity from 45.4 to 83.4 %. We found that break periods in cooler areas led to lower pulse rates and prevented excessive pulse pressure decreases after exercise. Additionally, the combination of a cooler environment during breaks with a cooling jacket led to lower maximum forehead skin temperatures during the subsequent work periods. However, workers tended to report higher tiredness levels when break areas were cooler. Therefore, while providing cool rest areas is beneficial for worker recovery and preventing heat-related illnesses, the potential negative effects on workers’ perception of tiredness should be considered.

THE EFFECT OF WATER DOUSING ON HEAT STRAIN AND PERFORMANCE DURING ENDURANCE RUNNING IN THE HEAT

INTRODUCTION Water dousing (pouring water on the body) is an easy-to-implement cooling method while running due to the availability of water at race aid stations, and may decrease the risk of heat illness and improve performance. However, dousing has not been investigated in extended duration running (i.e., ≥10 km), a typical distance in both elite and community level events. AIMS: Assess the effect of water dousing on heat strain and performance during self-paced and fixed-intensity exercise in the heat. DESIGN: Crossover, block randomised controlled trial. METHODS 13 trained runners completed a 10 km time trial (TT) and 60 min fixed pace run (60% velocity of VO2max) in a 30°C, 47% relative humidity environment using either water dousing (DOUSE) or no dousing (CON). RESULTS 10 km TT performance was faster in DOUSE compared to CON (44:11±6:14 vs. 44:38±6:03 min:s; p=0.033). Change in core temperature (Tc) was not different between groups during the TT (+0.02±0.33°C in DOUSE; p=0.853) or fixed pace run (+0.02±0.30°C; p=0.848). Change in mean skin temperature (Tsk) was lower in DOUSE during the TT (-1.80±0.63°C; p&amp;lt;0.001) and fixed pace run (-1.38±0.78°C; p&amp;lt;0.001). Heart rate (HR) was lower for DOUSE during the fixed pace run (-3.5±5.5 bpm; p=0.041) but not during the TT (-0.2±4.2 bpm; p=0.853). Thermal sensation was lower for DOUSE during the TT (-49.3±41.9 mm; p&amp;lt;0.001) and fixed pace run (-44.7±27.6 mm; p&amp;lt;0.001). Rating of perceived exertion (RPE) was not different between groups for the TT (-0.2±0.9; p=0.390) or fixed pace run (-0.2±1.0; p=0.480). CONCLUSION Water dousing improves 10 km TT performance in the heat but does not mitigate a rise in Tc. The positive change in thermal perception (via lower skin temperature) likely drives this ergogenic effect.

Spinal cord electrical stimulation with neurophysiological monitoring for treatment of high-risk diabetic foot

To evaluate the clinical efficacy of a single-session implantation of spinal cord electrical stimulation with neurophysiological monitoring a spinal cord electrical stimulator under general anesthesia with neurophysiological monitoring for the treatment of high-risk diabetic foot. The clinical data of seven patients with high-risk diabetic foot who underwent spinal cord electrical stimulation in neurosurgery ward nine of Tianjin Huanhu Hospital from May 2022 to May 2023 were collected. The operation was performed under general anesthesia with the "C" arm X ray machine guidance and neurophysiological monitoring. The arterial diameter and peak flow rate of lower extremity, lower extremity skin temperature (calf skin temperature, foot skin temperature), visual analog scale (VAS), continuous distance of movement, blood glucose level and toe wound were compared between patients before and after surgery. A total of seven patients with high-risk diabetic foot were included. The diameters and peak flow rates of femoral artery, popliteal artery, anterior tibial artery, posterior tibial artery and dorsal foot artery in both lower limbs were significantly improved after surgery. All patients had different degrees of lower limb pain before operation. After operation, VAS score decreased significantly (1.1±0.9 vs. 6.8±3.4), the pain was significantly relieved, and the calf skin temperature and foot skin temperature were significantly higher than those before surgery [calf skin temperature (centigrade): 33.3±0.9 vs. 30.9±0.7, foot skin temperature (centigrade): 31.4±0.8 vs. 29.1±0.6], fasting blood glucose and postprandial blood glucose were significantly lower than those before surgery [fasting blood glucose (mmol/L): 7.6±1.4 vs. 10.5±1.2, postprandial blood glucose (mmol/L): 9.3±2.3 vs. 13.5±1.1], the differences were statistically significant (all P < 0.01). The lower limb movement of all seven patients was significantly improved after surgery, including one patient who needed wheelchair travel before surgery, and one patient who had intermittent claudication before surgery. Among them, one patient needed wheelchair travel and one patient had intermittent claudication before surgery. All patients could walk normally at 2 weeks after operation. Among the seven patients, two patients had the diabetic foot wound ulceration before surgery, which could not heal for a long time. One month after surgery, blood flow around the foot wound recovered and the healing was accelerated. The wound was dry and crusted around the wound, and the wound healed well. For diabetic high-risk foot patients who are intolerant to diabetic peripheral neuralgia and local anesthesia spinal cord electrical stimulation test, one-time implantation of spinal cord electrical stimulator under general anesthesia under neurophysiological monitoring can effectively alleviate peripheral neuralgia and other diabetic foot related symptoms, improve lower limb blood supply, and reduce the risk of toe amputation. Clinical practice has proved the effectiveness of this technique, especially for the early treatment of diabetic high-risk foot patients.

Gender disparities in thermal responses under vertical air temperature differences

The effects of vertical temperature differences (VTD) on human thermal comfort have attracted growing attention from researchers when utilizing split air conditioners for winter heating. This study underscores the need to investigate the influences of gender disparities in the context of significant vertical temperature variations, a critical aspect that has not yet been comprehensively explored. Twenty gender-balanced subjects were exposed to a variety of stratified thermal environments created by a split air-conditioner. Their overall and local perceptual and physiological responses were measured at various operative temperatures and VTD. Results show that females have lower thermal sensation vote (TSV) and mean skin temperature under the same environments compared to males. Neutral operative temperatures of females and males are 23.7 ˚C and 20.8 ˚C, respectively. On the cold side, lower leg and foot thermal sensations are dominant whereas chest and back are dominant on the warm side. When females rated “slightly warm” (TSV equaled 1) or “warm” (TSV equaled 2), or males rated “slightly cool” (TSV equaled −1), increased VTD can lower thermal acceptability. The research findings have significant implications for the understanding of gender requirements of stratified heating environments and for maximizing the thermal comfort of the two genders.

Response of skin temperature, blood ammonia and lactate during incremental exercise until exhaustion in elite athletes

The study aimed to evaluate the lower limb skin temperature (Tsk) and blood concentrations of lactate (LA) and ammonia (NH3) during exercise and recovery. Eleven elite sprint athletes (25 ± 3.4 yrs) and 11 elite endurance athletes (24.45 ± 5.4 yrs) performed an incremental running test until exhaustion. Body composition was estimated using the DXA method. Thermograms of the anterior and posterior surfaces of the lower limbs were recorded at rest, before each test stage (every 3 min, starting from 10 km h−1 and increasing by 2 km h−1), and in the 5th, 10th, 15th, 20th, and 30th minute of recovery. Endurance athletes had a higher maximum oxygen uptake than sprint athletes (5.0 ± 0.7 vs 4.3 ± 0.4 l·kg−1, p = 0.018), lower percentage of lean content (79 ± 2 vs 83 ± 2%, p < 0.001), and a higher percentage of fat content in the lower limbs (17 ± 2 vs 12 ± 2%, p < 0.001). In both groups, a significant decrease in Tsk was observed compared to resting value (endurance athletes—31.5 ± 0.6 °C; sprint athletes—32.3 ± 0.6 °C), during exercise (p < 0.001) and rewarming during recovery (p < 0.001). However, endurance athletes had a lower Tsk than sprint athletes at the exhaustion point (30.0 ± 1.1 vs 31.6 ± 0.8 °C, p < 0.05) and the pattern of change in Tsk differed between groups (p < 0.001). Tsk in the endurance athletes group decreased throughout the exercise protocol and returned more rapidly to initial values during recovery, while Tsk in the sprint group stabilised between moderate intensity and exhaustion, recovering more slowly after exercise. Both LA (endurance athletes—max 10.2 ± 1.5; sprint athletes—max 10.1 ± 1.4 mmol⋅L−1, p < 0.001) and NH3 (endurance athletes—max 75.6 ± 11.5; sprint athletes—max 76.7 ± 9.0 mmol⋅L−1, p < 0.001) increased during exercise and decreased during recovery (p < 0.001). During exercise, lower levels and slower increases in LA were observed during exercise in the endurance athletes’ group (p < 0.05). A negative correlation was revealed between Tsk and fat percentage (r = −0.43 to −0.71, p < 0.05). Tsk was positively correlated with LA during recovery (r = 0.43 to 0.48, p < 0.05), and negatively during recovery (r = −0.45 to −0.54, p < 0.05). Differences between groups in maximum aerobic capacity, the pattern of change in Tsk, and the correlation between Tsk and LA suggest that individuals who decrease less Tsk during exercise and higher Tsk during recovery are those with better aerobic capacity. In addition, athletes with less body fat dissipate heat from their tissues more efficiently.

Multi-inspired Janus fabrics with asymmetric coolmax patterns for rapid sweat diffusion and effective sweat-shedding

Janus fabrics with unidirectional liquid transport property have attracted wide attention for their ability to remove excess sweat and lower skin temperature. However, most Janus fabrics face the sweat removal issue on their outer surface when the sweat absorption capacity of their hydrophilic surface reaches limit, which inevitably slows down one-way sweat transport rate and induces the fabrics to become heavy/clingy. Herein, inspired by natural Namib Desert beetles and drip tips, circular Coolmax patterns (severed as sweat extraction points near the skin) and triangular Coolmax patterns (severed as sweat removal zones on the outside of the fabric) are asymmetrically sewn on superhydrophobic cotton fabrics to enable continues one-way sweat transport and allow effective sweat diffusion/shedding on its outer surface. During the sweat transporting and evaporation process, a large amount of heat is dissipated. As a result, the created Janus fabrics can maintain human body temperature about 1.3 ℃ lower than the conventional cotton fabric. Moreover, the low adhesion (∼0.2 mN cm−2) between the wet skin and the fabric makes wearers feel more comfortable. The method can be potentially used for the large-scale commercial production of Janus fabrics and provide insights for the development of smart fabrics in the future.

Skin temperature influence on transcutaneous carbon dioxide (CO2) conductivity and skin blood flow in healthy human subjects at the arm and wrist.

Objective: present transcutaneous carbon dioxide (CO2)-tcpCO2-monitors suffer from limitations which hamper their widespread use, and call for a new tcpCO2 measurement technique. However, the progress in this area is hindered by the lack of knowledge in transcutaneous CO2 diffusion. To address this knowledge gap, this study focuses on investigating the influence of skin temperature on two key skin properties: CO2 permeability and skin blood flow. Methods: a monocentric prospective exploratory study including 40 healthy adults was undertaken. Each subject experienced a 90 min visit split into five 18 min sessions at different skin temperatures-Non-Heated (NH), 35, 38, 41, and 44°C. At each temperature, custom sensors measured transcutaneous CO2 conductivity and exhalation rate at the arm and wrist, while Laser Doppler Flowmetry (LDF) assessed skin blood flow at the arm. Results: the three studied metrics sharply increased with rising skin temperature. Mean values increased from the NH situation up to 44°C from 4.03 up to 8.88 and from 2.94 up to 8.11 m·s-1 for skin conductivity, and from 80.4 up to 177.5 and from 58.7 up to 162.3 cm3·m-2·h-1 for exhalation rate at the arm and wrist, respectively. Likewise, skin blood flow increased elevenfold for the same temperature increase. Of note, all metrics already augmented significantly in the 35-38°C skin temperature range, which may be reached without active heating-i.e. only using a warm clothing. Conclusion: these results are extremely encouraging for the development of next-generation tcpCO2 sensors. Indeed, the moderate increase (× 2) in skin conductivity from NH to 44°C tends to indicate that heating the skin is not critical from a response time point of view, i.e. little to no skin heating would only result in a doubled sensor response time in the worst case, compared to a maximal heating at 44°C. Crucially, a skin temperature within the 35-38°C range already sharply increases the skin blood flow, suggesting that tcpCO2 correlates well with the arterial paCO2 even at such low skin temperatures. These two conclusions further strengthen the viability of non-heated tcpCO2 sensors, thereby paving the way for the development of wearable transcutaneous capnometers.

Radiative cooling textiles using industry-standard particle-free nonporous micro-structured fibers.

Thermal radiation is a major dissipative pathway for heat generated by the human body and offers a significant thermoregulation mechanism over a wide range of conditions. We could use this in garment design to enhance personal cooling, which can improve the wearing comfort of garments or even result in energy savings in buildings. At present, however, radiative cooling has received insufficient attention in commercial design and production of textiles for wearable garments. Textiles that efficiently transmit the radiative heat were recently demonstrated, but either do not utilize standard weaving and knitting processes for wearable garments or require substantial process modifications. Here, we demonstrate the design and implementation of large-scale radiative cooling textiles for localized cooling management and enhanced thermal comfort using industry-standard particle-free nonporous micro-structured fibers that are fully compatible with standard textile materials and production methods. The micro-structured fibers, yarns and fabrics are part of a hierarchical photonic structure design that renders the textiles highly infrared transparent (up to > 0.8) while assuring visual opacity (up to 0.99). We design radiative cooling textiles with first-principles electromagnetic methods and fabricate them using commercial textile materials and formation facilities. Our "fabless" approach is confirmed by very good quantitative agreement between design and measurements. The resulting fabrics exhibit wearability properties expected of wearable textiles, and lower skin temperature by ≥ 3 °C compared to conventional textiles, which offers the potential for > 30 % energy savings in buildings and increases wearing comfort by significantly reducing the reliance on latent heat dissipation for thermoregulation.

Effects of Parallel Contact Cooling on Pulsed-Type, Bipolar Radiofrequency-Induced Tissue Reactions in an in vivo Porcine Model.

Skin cooling during laser or radiofrequency (RF) treatments is a method to minimize thermal damage to the epidermis, reduce pain, and decrease post-treatment downtime. We evaluated the effect of parallel contact cooling (PCC) on RF-induced thermal reactions in minipig skin in vivo after bipolar microneedling RF treatment. RF treatments were administered at frequencies of 0.5, 1, and 2 MHz with single (500 ms), six (1000 ms), and ten (5000 ms) sub-pulse packs to minipig skin with or without PCC. Subsequently, thermometric imaging and histology were used to analyze skin reactions to RF. Thermometric images showed that PCC promptly lowered skin temperature in the RF-treated area, with this effect persisting for over 60s. Regardless of the PCC, RF treatments lasting for 500 ms with a single pulse pack resulted in peri-electrode coagulative necrosis (PECN) zones and inter-electrode non-necrotic thermal reaction (IENT) zones in the dermis. In contrast, treatment lasting 5000 ms with 10 sub-pulse packs produced distinct IENT without notable PECN over a wide dermal area. Skin specimens obtained at 1 h and 3, 7, and 14 days after PCC-assisted RF treatments showed a higher degree of thermal tissue reactions in the deeper dermal regions compared to those after RF treatments without PCC. PCC-assisted RF treatment, utilizing an invasive bipolar microneedling device, enhanced RF-induced skin reactions in the mid to deep dermis while preserving the epidermis and upper papillary dermis from excessive thermal tissue injury.

The gender and age differences in the passengers' thermal comfort during cooling and heating conditions in vehicles.

The thermal physiological and psychological responses in vehicles, influenced by gender and age, play a crucial role in ensuring passengers' comfort. However, these differences have often been overlooked. This study aims to comprehensively examine passengers' thermal comfort and investigate gender and age disparities based on their physiological and psychological responses. Experiments were conducted inside a vehicle placed in a climate chamber under cooling and heating conditions, with the collected data subjected to statistical analysis. The findings reveal that males had significantly higher mean skin temperatures in cooling conditions and lower skin temperatures in heating conditions than females. However, overall thermal sensation and comfort did not significantly differ between genders. Interestingly, age-related differences were observed to a limited extent in both conditions. This study provides valuable insights into passengers' thermal responses in vehicles, considering the factors of gender and age, thereby contributing to a comprehensive understanding of thermal comfort in a vehicle environment.

Comparison Between the Efficacy of Spinal Cord Stimulation and of Endovascular Revascularization in the Treatment of Diabetic Foot Ulcers: A Retrospective Observational Study

ObjectiveWe aimed to compare the effects of spinal cord stimulation (SCS) with those of endovascular revascularization on the treatment of diabetic foot ulcers. Materials and MethodsA total of 104 patients with diabetic foot ulcers who met the inclusion criteria were retrospectively analyzed and classified to the SCS treatment group (n = 46) and endovascular revascularization treatment group (n = 46). The quality-of-life scores (Quality of Life Scale for Patients with Liver Cancer v2.0), visual pain analog scale score, lower limb skin temperature, lower limb arterial ultrasound results, and lower extremity electromyography results were analyzed to compare the efficacy of the two treatments for diabetic foot ulcers in the two groups before surgery and six months after surgery. ResultsA total of 92 patients (men: 73.9%, mean age: 66.51 ± 11.67 years) completed the six-month postoperative follow-up period. The patients in the SCS treatment group had a higher quality-of-life score (25.54% vs 13.77%, p < 0.05), a larger reduction in pain scores (69.18% vs 37.21%, p < 0.05), and a larger reduction in foot temperature (18.56% vs 7.24%, p < 0.05) than those of the endovascular revascularization treatment group at six months after surgery. The degree of vasodilation in the lower limbs on color Doppler arterial ultrasound and the nerve conduction velocity were higher in the SCS treatment group than in the endovascular revascularization treatment group at six months after surgery (p < 0.05). ConclusionSCS was more effective than endovascular revascularization in improving quality of life, relieving pain, improving lower limb skin temperature, increasing lower limb blood flow, and improving nerve conduction in patients with diabetic foot ulcers at six months after surgery.

Dynamic comfort criteria – A possible solution to the conflict between heat balance and adaptive thermal comfort models

Physiologists typically assume that optimal thermal comfort can only be achieved by minimizing thermoregulatory efforts. People are thus believed to be thermally comfortable with a mean skin temperature of 33–34 °C and minimized sweating rate at a low metabolic rate. Many heat balance comfort models are established based on these fixed comfort criteria. However, occupants’ thermal requirements are found to be more flexible and dynamic because of physiological and psychological adaptions. In this study, dynamic comfort criteria (DCC) are proposed to consider the adaption in the PMV model. Occupants tend to accept a lower skin temperature in a cold climate and a slightly higher sweating rate in a hot climate. We provide two methods to infer DCC based on ASHRAE thermal comfort database II. One is to develop a generalized DCC that can be applied globally. Another is to use Bayesian calibration to develop a customized DCC that further localizes the thermal requirements. With DCC, the deficiency of the PMV and the adaptive model can be largely eliminated. Unlike PMV, the model with DCC performs consistently in different operation modes. DCC is conceptually different from actual physiological responses, although they can sometimes be close to each other in values. The study paves the road for unifying comfort theories and equipping traditional comfort models with the ability to re-learn.