The hypothermic nature of fungi.

Fungi play essential roles in global health, ecology, and economy, but their thermal biology is relatively unexplored. Mushrooms, the fruiting body of mycelium, were previously noticed to be colder than surrounding air through evaporative cooling. Here, we confirm those observations using infrared thermography and report that this hypothermic state is also observed in mold and yeast colonies. The relatively colder temperature of yeasts and molds is also mediated via evaporative cooling and associated with the accumulation of condensed water droplets on plate lids above colonies. The colonies appear coldest at their center and the surrounding agar appears warmest near the colony edges. The analysis of cultivated Pleurotus ostreatus mushrooms revealed that the hypothermic feature of mushrooms can be observed throughout the whole fruiting process and at the level of mycelium. The mushroom's hymenium was coldest, and different areas of the mushroom appear to dissipate heat differently. We also constructed a mushroom-based air-cooling prototype system capable of passively reducing the temperature of a semiclosed compartment by approximately 10 °C in 25 min. These findings suggest that the fungal kingdom is characteristically cold. Since fungi make up approximately 2% of Earth's biomass, their evapotranspiration may contribute to cooler temperatures in local environments.

Hyperspectral imaging reveals small-scale water gradients in apple leaves due to minimal cuticle perforation by Venturia inaequalis conidiophores.

Effects of Venturia inaequalis on water relations of apple leaves were studied under controlled conditions without limitation of water supply to elucidate their impact on the non-haustorial biotrophy of this pathogen. Leaf water relations, namely leaf water content and transpiration, were spatially resolved by hyperspectral imaging and thermography; non-imaging techniques-gravimetry, a pressure chamber, and porometry-were used for calibration and validation. Reduced stomatal transpiration 3-4 d after inoculation coincided with a transient increase of water potential. Perforation of the plant cuticle by protruding conidiophores subsequently increased cuticular transpiration even before visible symptoms occurred. With sufficient water supply, cuticular transpiration remained at elevated levels for several weeks. Infections did not affect the leaf water content before scab lesions became visible. Only hyperspectral imaging was suitable to demonstrate that a decreased leaf water content was strictly limited to sites of emerging conidiophores and that cuticle porosity increased with sporulation. Microscopy confirmed marginal cuticle injury; although perforated, it tightly surrounded the base of conidiophores throughout sporulation and restricted water loss. The role of sustained redirection of water flow to the pathogen's hyphae in the subcuticular space above epidermal cells, to facilitate the acquisition and uptake of nutrients by V. inaequalis, is discussed.

Thermographic assessment of mastitis progression in sahiwal cattle: Insights into the patterns in the natural course of infection.

Mastitis is a global concern in the dairy sector, demanding innovative solutions for effective management for quality lifetime milk production. In this study, infrared thermography (IRT) as a non-invasive technology was integrated into routine farm activities for continuous health monitoring of animals. For 30 days, we systematically monitored the udder health status in 40 Sahiwal cows (160 quarters), employing IRT along with the California Mastitis Test (CMT). We also assessed somatic cell count (SCC), microbial identification, and milk quality parameters of representative samples. The thermal imaging data was analyzed, considering both backward propagation from the 0th day to the -10th day and forward propagation from the 0th day to the +10th day. Our findings revealed that on the 0th day, the mean temperatures of the udder surface skin temperature (USST) and teat skin surface temperature (TSST) exhibited differences (p < 0.05) between the quarters affected by sub-clinical mastitis (SCM) and clinical mastitis (CM) in comparison to the healthy quarters, with the highest degree of difference observed. The observed temperature differences between CM and SCM quarters compared to healthy ranged from 1.8 to 3.62 °C and 0.98 to 3.23 °C for USST, and from 1.68 to 3.16 °C and 0.56 to 2.32 °C for TSST, respectively. Furthermore, our observations indicated that both udder and teat quarters responded differently to mastitis. A temperature rise of 1.37 °C in SCM quarters and 1.75 °C in CM quarters was observed between the -10th and -8th day relative to day 0, with the increase being more pronounced in the morning hours. Also, a notable temperature surge occurred during the -2nd and -1st days relative to the 0th day. The log10SCC values and milk quality parameters significantly differed (p < 0.05) between mastitis-affected and healthy samples. In addition, Staphylococcus spp. was identified as the predominant mastitis-causing pathogen in the bacteriological identification conducted in this study. Therefore, IRT efficiently assesses the initiation point of udder infection in Sahiwal cows, aiding in effective udder health management.

Preliminary study of finger temperature recovery in patients with diabetes mellitus following cold stimulation.

OBJECTIVE: To explore the difference in temperature recovery following cold stimulation between participants with and without diabetes mellitus (DM). MATERIALS AND METHODS: The participants without (control group; n = 25) and with (DM group; n = 26) DM were subjected to local cold stimulation (10º C for 90 s). The thermal images of their hands were continuously captured using a thermal camera within 7 min following cold stimulation, and the highest temperature of each fingertip was calculated. According to the temperature values at different timepoints, the temperature recovery curves were drawn, and the baseline temperature (T-base), initial temperature after cooling (T0), temperature decline amplitude (T-range), and area under the temperature recovery curve > T0 (S) were calculated. Finally, symmetry differences between the two groups were analysed. RESULTS: No statistical differences in the T-base, T0, and T-range were observed between the DM and control groups. After drawing the rewarming curve according to the temperature of the fingertips of the patients following cold stimulation, the S in the DM group was significantly lower than that in the control group (p < 0.05). Furthermore, the asymmetry of the base temperature of the hand was observed in the DM group. CONCLUSIONS: Following cold stimulation, the patients with DM exhibited a different rewarming pattern than those without DM. Thus, cold stimulation tests under infrared thermography may contribute to the early screening of diabetic peripheral neuropathy in future.

Implications of heat exchange for a free-living endangered marsupial determined by non-invasive thermal imaging.

We used thermal imagining and heat balance modelling to examine the thermal ecology of wild mammals, using the diurnal marsupial numbat (Myrmecobius fasciatus) as a model. Body surface temperature was measured using infra-red thermography at environmental wet and dry bulb temperatures of 11.7-29°C and 16.4-49.3°C, respectively; surface temperature varied for different body parts and with environmental temperature. Radiative and convective heat exchange varied markedly with environmental conditions and for various body surfaces reflecting their shapes, surface areas and projected areas. Both the anterior and posterior dorsolateral body areas functioned as thermal windows. Numbats in the shade had lower rates of solar radiative heat gain but non-solar avenues for radiative heat gain were substantial. Radiative gain was higher for black and lower for white stripes, but overall, the stripes had no thermal role. Total heat gain was generally positive (<4 to >20 W) and often greatly exceeded metabolic heat production (3-6 W). Our heat balance model indicates that high environmental heat loads limit foraging in open areas to as little as 10 min and that climate change may extend periods of inactivity, with implications for future conservation and management. We conclude that non-invasive thermal imaging is informative for modelling heat balance of free-living mammals.

Protocol description and initial experience in kidney graft perfusion using infrared thermography.

PURPOSE: Protocol description for renal perfusion study using thermographic technology and description of the thermographic and clinical behavior of the transplanted kidneys before and after unclamping. METHODS: Infrared thermographic images of renal grafts are obtained before kidney reperfusion, 10 min after and just before closing the surgical wound. Thermographic data is evaluated together with the type of graft and donor, cold ischemia time, hypovascularized areas determined by the surgeon during surgical intervention, alterations in vascular flow in postoperative echo-Doppler, time at the beginning of graft function and serum creatinine monitoring during postoperative follow-up. RESULTS: 17 grafts were studied. The mean temperature of the grafts before reperfusion, 10 min after and at the end of the surgery were 18.7 °C (SD 6.27), 32.36 °C (SD1.47) and 32.07 °C (SD1.78) respectively. 4 grafts presented hypoperfused areas after reperfusion. These areas presented a lower temperature compared to the well perfused parenchyma surface using thermographic images. CONCLUSION: The study of the usefulness and applicability of thermography can allow the development of tools that provide additional objective information on organ perfusion in real time and non-invasive manner. Our protocol and initial results can contribute to provide new evidence. Further analyses should be developed to shed light on the role of this technology.

Facial and ocular thermal mapping in black-and-gold howler monkey (Alouatta caraya) by infrared thermography: An ex situ study.

BACKGROUND: This study used infrared thermography (IRT) for mapping the facial and ocular temperatures of howler monkeys, to determine parameters for the diagnosis of febrile processes. There are no published IRT study in this species. METHODS: Were evaluated images of a group of monkeys kept under human care at Sorocaba Zoo (São Paulo, Brazil). The images were recorded during 1 year, in all seasons. Face and eye temperatures were evaluated. RESULTS: There are statistically significant differences in face and eye temperatures. Mean values and standard deviations for facial and ocular temperature were respectively: 33.0°C (2.1) and 36.5°C (1.9) in the summer; 31.5°C (4.5) and 35.3°C (3.6) in the autumn; 30.0°C (4.3) and 35.6°C (3.9) in the winter; 30.8°C (2.9) and 35.5°C (2.1) in the spring. CONCLUSIONS: The IRT was effective to establish a parameter for facial and ocular temperatures of black-and-gold howler monkeys kept under human care.

Short-term effects of 448 kilohertz radiofrequency stimulation on plantar fascia measured by quantitative ultrasound elastography and thermography on active healthy subjects: an open controlled clinical trial.

Objective: This study is an open clinical trial. The aim of this study was to show the changes that occur in the viscoelastic properties of the plantar fascia (twenty healthy volunteers) measured by SEL and the changes in the plantar fascia temperature measured by thermography after the application of a 448 kHz capacitive resistive monopolar radiofrequency (CRMR) in active healthy subjects immediately after treatment and at the 1-week follow-up.Methods: Furthermore, to analyze if an intervention with 448 kHz CRMR in the plantar fascia of the dominant lower limb produces a thermal response in the plantar fascia of the non-dominant lower limb. The final objective was to analyze the level of association between the viscoelastic properties of the PF and the temperature before and after the intervention with 448 kHz CRMR.Results: Our results showed that a temperature change, which was measured by thermography, occurred in the plantar fascia after a single intervention (T0-T1) and at the 1-week follow up (T1-T2).Conclusion: However, no changes were found in the viscoelastic properties of the plantar fascia after the intervention or at the 1-week follow up. This is the first study to investigate changes in both plantar fascia viscoelastic properties and in plantar fascia temperature after a radiofrequency intervention.

Combining analytical techniques to assess the translocation of diesel particles across an alveolar tissue barrier in vitro.

BACKGROUND: During inhalation, airborne particles such as particulate matter ≤ 2.5 µm (PM2.5), can deposit and accumulate on the alveolar epithelial tissue. In vivo studies have shown that fractions of PM2.5 can cross the alveolar epithelium to blood circulation, reaching secondary organs beyond the lungs. However, approaches to quantify the translocation of particles across the alveolar epithelium in vivo and in vitro are still not well established. In this study, methods to assess the translocation of standard diesel exhaust particles (DEPs) across permeable polyethylene terephthalate (PET) inserts at 0.4, 1, and 3 µm pore sizes were first optimized with transmission electron microscopy (TEM), ultraviolet-visible spectroscopy (UV-VIS), and lock-in thermography (LIT), which were then applied to study the translocation of DEPs across human alveolar epithelial type II (A549) cells. A549 cells that grew on the membrane (pore size: 3 µm) in inserts were exposed to DEPs at different concentrations from 0 to 80 µg.mL- 1 ( 0 to 44 µg.cm- 2) for 24 h. After exposure, the basal fraction was collected and then analyzed by combining qualitative (TEM) and quantitative (UV-VIS and LIT) techniques to assess the translocated fraction of the DEPs across the alveolar epithelium in vitro. RESULTS: We could detect the translocated fraction of DEPs across the PET membranes with 3 µm pore sizes and without cells by TEM analysis, and determine the percentage of translocation at approximatively 37% by UV-VIS (LOD: 1.92 µg.mL- 1) and 75% by LIT (LOD: 0.20 µg.cm- 2). In the presence of cells, the percentage of DEPs translocation across the alveolar tissue was determined around 1% at 20 and 40 µg.mL- 1 (11 and 22 µg.cm- 2), and no particles were detected at higher and lower concentrations. Interestingly, simultaneous exposure of A549 cells to DEPs and EDTA can increase the translocation of DEPs in the basal fraction. CONCLUSION: We propose a combination of analytical techniques to assess the translocation of DEPs across lung tissues. Our results reveal a low percentage of translocation of DEPs across alveolar epithelial tissue in vitro and they correspond to in vivo findings. The combination approach can be applied to any traffic-generated particles, thus enabling us to understand their involvement in public health.

An efficient multi-level thresholding method for breast thermograms analysis based on an improved BWO algorithm.

Breast cancer is a prevalent disease and the second leading cause of death in women globally. Various imaging techniques, including mammography, ultrasonography, X-ray, and magnetic resonance, are employed for detection. Thermography shows significant promise for early breast disease detection, offering advantages such as being non-ionizing, non-invasive, cost-effective, and providing real-time results. Medical image segmentation is crucial in image analysis, and this study introduces a thermographic image segmentation algorithm using the improved Black Widow Optimization Algorithm (IBWOA). While the standard BWOA is effective for complex optimization problems, it has issues with stagnation and balancing exploration and exploitation. The proposed method enhances exploration with Levy flights and improves exploitation with quasi-opposition-based learning. Comparing IBWOA with other algorithms like Harris Hawks Optimization (HHO), Linear Success-History based Adaptive Differential Evolution (LSHADE), and the whale optimization algorithm (WOA), sine cosine algorithm (SCA), and black widow optimization (BWO) using otsu and Kapur's entropy method. Results show IBWOA delivers superior performance in both qualitative and quantitative analyses including visual inspection and metrics such as fitness value, threshold values, peak signal-to-noise ratio (PSNR), structural similarity index measure (SSIM), and feature similarity index (FSIM). Experimental results demonstrate the outperformance of the proposed IBWOA, validating its effectiveness and superiority.

Capturing temperature changes on the ocular surface along with estrus and ovulation using infrared thermography in Japanese Black cows.

Pre-ovulatory follicles are cooler than the neighboring reproductive organs in cows. Thus, measuring the temperature of reproductive organs could be a useful method for predicting estrus and ovulation in cows, and the establishment of a non-invasive technique is required. In this study, we used infrared thermography (IRT) to measure ocular surface temperature as a potential surrogate for reproductive organ temperature. Five Japanese Black cows with synchronized estrus were subjected to temperature measurements in five regions of the ocular surface, including the nasal conjunctiva, nasal limbus, center cornea, temporal limbus, and temporal conjunctiva, twice a day (0800 h and 1600 h) during the experimental period. The temperatures in the five regions significantly declined in cows from estrus to ovulation. To the best of our knowledge, this study is the first to use IRT to show a temperature decrease in the ocular surface along with estrus to ovulation in Japanese Black cows.

Effect of access to natural shade on scrotal thermoregulatory capacity, integrity of the testicular parenchyma and sperm morphology of Nelore (Bos indicus) and Canchim (Bos taurus x Bos indicus) bulls.

The objective of this work was to evaluate the effect of using naturally shaded pastures on scrotal thermoregulatory capacity, testicular echotexture, and sperm morphology of Nelore (Bos indicus) and Canchim (5/8 Bos taurus x 3/8 Bos indicus) bulls in a tropical climate region. Sixty-four adult Nelore and Canchim bulls were used, equally allocated in Full Sun (FS, n = 32) or Crop-Livestock-Forestry (CLF, n = 32) pasture systems. During five consecutive climate seasons, the bulls underwent monthly breeding soundness evaluations and the biometeorological variables in the systems were continuously monitored. Microclimate was significantly different between systems. CLF system had lower BGHI than FS throughout the experimental period. No triple interaction (Season x Breed x Treatment, P > 0.05) was observed for any of the variables. Animals in CLF showed lower body temperature in Summer (FS:39.41 ± 0.05 vs. CLF:39.30 ± 0.05 °C; P = 0.005) and in Autumn (FS:39.54 ± 0.05 vs. CLF:39.35 ± 0.05 °C; P = 0.005). Access to shading did not determine differences in the evolution of scrotal biometry, temperatures, and scrotal thermal gradients (P > 0.05). Regardless of breed, animals in CLF showed greater right testicular volume (FS:247.5 ± 5.7 vs. CLF:259.0 ± 5.7 cm³; P < 0.05), more suitable parenchyma echotexture, and fewer microlithiasis spots in the Spring and Summer. Testosterone concentration was higher in FS (FS:2.6 ± 0.2 vs. CLF:2.1 ± 0.2 ng/mL; P = 0.035). Canchim bulls presented higher total sperm defects during the Autumn and Winter (P = 0.010), but the total defects levels for Canchim and Nelore bulls were in normal range for adult bulls. Thus, the natural shade in CLF system was effective in improving the microclimate of pastures and minimizing adverse environmental effects on some reproductive features of interest in beef cattle.

Estimation of Heat Production Rate using Thermal Data During Exercise in Indoor Environments: A Study of Heat Storage Rate in Male Athletes.

The increasing preference for indoor exercise spaces highlights the relationship between indoor thermal environments and physiological responses, particularly concerning thermal comfort during physical activity. Determining the metabolic heat production rate during exercise is essential for optimizing the thermal comfort, well-being, and performance of individuals engaged in physical activities. This value can be determined during the activity using several methods, including direct calorimetry measurement, indirect calorimetry that uses analysis of respiratory gases, or approximations using collected data such as speed, body mass, and heart rate. The study aimed to calculate the metabolic heat production rate by infrared thermal evaluation (ITE) based on the body's thermal balance approach and compare it with the values determined by indirect calorimetry (IC). Fourteen participants volunteered for the study, using a cycling ergometer in a controlled climatic chamber. After the familiarization sessions, maximal O2 intake levels (VO2max) were determined through maximal graded exercise tests. Subsequently, constant work rate exercise tests were performed at 60% of VO2max for 20 min. The metabolic heat production rates were calculated by IC and ITE for each athlete individually. Respiratory gases were used to determine IC, while body skin and core temperatures, along with physical environmental data, were applied to calculate ITE using the human body thermal balance approximation of ASHRAE. According to the results, heat storage rates were misleading among the body's heat transfer modes, particularly during the first 8 min of the exercise. ITE showed a moderate level of correlation with IC (r: 0.03-0.86) with a higher level of dispersion relative to the mean (CV%: 12-84%). Therefore, a new equation (ITEnew) for the heat storage rates was proposed using the experimental data from this study. The results showed that ITEnew provided more precise estimations for the entire exercise period (p > 0.05). Correlations between ITEnew and IC values were consistently strong throughout the exercise period (r: 0.62-0.85). It can be suggested that ITEnew values can predict IC during the constant work rate steady-state exercise.

Advances in far-infrared research: therapeutic mechanisms of disease and application in cancer detection.

Far infrared (FIR) irradiation is commonly used as a convenient, non-contact, non-invasive treatment for diseases such as myocardial ischemia, diabetes, and chronic kidney disease. In this review, we focus on reviewing the potential therapeutic mechanisms of FIR and its cutting-edge applications in cancer detection. Firstly, we searched the relevant literature in the last decade for systematic screening and briefly summarized the biophysical properties of FIR. We then focused on the possible mechanisms of FIR in wound healing, cardiovascular diseases, and other chronic diseases. In addition, we review recent applications of FIR in cancer detection, where Fourier transform infrared spectroscopy and infrared thermography provide additional diagnostic methods for the medical diagnosis of cancer. Finally, we conclude and look into the future development of FIR for disease treatment and cancer detection. As a high-frequency non-ionizing wave, FIR has the advantages of safety, convenience, and low cost. We hope that this review can provide biological information reference and relevant data support for those who are interested in FIR and related high-frequency non-ionizing waves, to promote the further application of FIR in the biomedical field.

Comparison of infrared thermography of the face between mouth-breathing and nasal-breathing children.

PURPOSE: To compare the temperature of thermoanatomic points and areas of the upper and lower lips between mouth-breathing and nasal-breathing children. METHODS: This cross-sectional observational study had a sample of 30 nasal-breathing and 30 mouth-breathing children aged 4 to 11 years. One front-view, one left-view, and one right-view infrared thermogram of the face were acquired from each participant. A total of 14 thermoanatomic points plus the upper lip and lower lip areas were marked on the front-view thermograms, while on the side-view thermograms, six thermoanatomic points were marked. The research also calculated the difference between the temperature of the upper and lower lip areas (∆T area) and between the temperature of the points on the upper and lower lips (∆T points). The normalized mean temperatures of points and areas and temperature differences were compared between groups with the t-test and Mann-Whitney test. RESULTS: The temperature of the thermoanatomic points closest to the lip (nasolabial, Labial Commissure, and lower labial), areas of the lips, and external acoustic meatus was lower in mouth breathers than in nasal breathers, which did not happen for most other points. ∆T area and ∆T points were not different between the groups. CONCLUSION: Thermography is a promising complementary diagnostic tool, since showed mouth-breathing children had lower temperatures in the region of the lips than nasal breathers.

Accuracy of infrared thermography evaluation in burn wound healing: a systematic review and meta-analysis.

OBJECTIVE: Accurate assessment of burn depth and burn wound healing potential is essential to determine early treatments. Infrared thermography (IRT) is a non-invasive and objective tool to do this. This systematic review evaluated the accuracy of IRT to determine burn wound healing potential. METHOD: This systematic review and meta-analysis used MEDLINE, EMBASE, CINAHL, PEDro, DiTA and CENTRAL databases. IRT data were extracted from primary studies and categorised into four cells (i.e., true positives, false positives, true negatives and false negatives). Subgroup analysis was performed according to methods used to capture thermal images. RESULTS: The search strategy identified 2727 publications; however, 15 articles were selected for review and 11 for meta-analysis. In our meta-analysis, the accuracy of IRT was 84.8% (63% sensitivity and 81.9% specificity). CONCLUSION: IRT is a moderately accurate tool to identify burn depth and healing potential. Thus, IRT should be used carefully for evaluating burn wounds.

Integrating technologies to enhance risk assessment for the early detection and prevention of pressure ulcers.

Pressure ulcers (PU) are a globally recognised healthcare concern, with their largely preventable development prompting the implementation of targeted preventive strategies. Risk assessment is the first step to planning individualised preventive measures. However, despite the long use of risk assessment, and the >70 risk assessment tools currently available, PUs remain a significant concern. Various technological advancements, including artificial intelligence, subepidermal moisture measurement, cytokine measurement, thermography and ultrasound are emerging as promising tools for PU detection, and subsequent prevention of more serious PU damage. Given the rise in availability of these technologies, this advances the question of whether our current approaches to PU prevention can be enhanced with the use of technology. This article delves into these technologies, suggesting that they could lead healthcare in the right direction, toward optimal assessment and adoption of focused prevention strategies.

Thermography Sensor to Assess Motor and Sensitive Neuromuscular Sequels of Brain Damage.

INTRODUCTION: The aim of this study was to observe the validity, diagnostic capacity, and reliability of the thermographic technique in the analysis of sensitive and motor sequelae in patients with chronic brain damage. METHOD: A longitudinal descriptive observational study was performed. Forty-five people with impairment in at least one anatomical region participated in and completed this study. All patients who had become infected by SARS-CoV-2 in the past year were excluded. Thermographic measurement was conducted, and the Modified Ashworth Scale and Pressure Pain Threshold was analyzed. RESULTS: A high correlation between two times of thermography data was observed. The Spearman correlations obtained between the Ashworth score on each leg and the temperature given by thermography were all significant. DISCUSSION AND CONCLUSIONS: Despite the above, the Spearman correlations obtained between the PPT in each leg and the temperature offered by thermography were not significant in any of the measurements. For this reason, thermography is a potential tool for the diagnosis and assessment of neuromuscular motor sequelae, but not for sensitive sequelae, after brain injury. Nevertheless, for the time being, no statistical relationship has been observed between the data reported by thermography and PPT; thus, future studies are needed to further investigate these results.

Analyzing the Thermal Characteristics of Three Lining Materials for Plantar Orthotics.

INTRODUCTION: The choice of materials for covering plantar orthoses or wearable insoles is often based on their hardness, breathability, and moisture absorption capacity, although more due to professional preference than clear scientific criteria. An analysis of the thermal response to the use of these materials would provide information about their behavior; hence, the objective of this study was to assess the temperature of three lining materials with different characteristics. MATERIALS AND METHODS: The temperature of three materials for covering plantar orthoses was analyzed in a sample of 36 subjects (15 men and 21 women, aged 24.6 ± 8.2 years, mass 67.1 ± 13.6 kg, and height 1.7 ± 0.09 m). Temperature was measured before and after 3 h of use in clinical activities, using a polyethylene foam copolymer (PE), ethylene vinyl acetate (EVA), and PE-EVA copolymer foam insole with the use of a FLIR E60BX thermal camera. RESULTS: In the PE copolymer (material 1), temperature increases between 1.07 and 1.85 °C were found after activity, with these differences being statistically significant in all regions of interest (p < 0.001), except for the first toe (0.36 °C, p = 0.170). In the EVA foam (material 2) and the expansive foam of the PE-EVA copolymer (material 3), the temperatures were also significantly higher in all analyzed areas (p < 0.001), ranging between 1.49 and 2.73 °C for EVA and 0.58 and 2.16 °C for PE-EVA. The PE copolymer experienced lower overall overheating, and the area of the fifth metatarsal head underwent the greatest temperature increase, regardless of the material analyzed. CONCLUSIONS: PE foam lining materials, with lower density or an open-cell structure, would be preferred for controlling temperature rise in the lining/footbed interface and providing better thermal comfort for users. The area of the first toe was found to be the least overheated, while the fifth metatarsal head increased the most in temperature. This should be considered in the design of new wearables to avoid excessive temperatures due to the lining materials.

Modelling and Thermographic Measurements of LED Optical Power.

This paper presents a simple engineering method for evaluating the optical power emitted by light-emitting diodes (LEDs) using infrared thermography. The method is based on the simultaneous measurement of the electrical power and temperature of an LED and a heat source (resistor) that are enclosed in the same plastic packaging under the same cooling conditions. This ensures the calculation of the optical power emitted by the LED regardless of the value of the heat transfer coefficient. The obtained result was confirmed by comparing it with the standard direct measurement method using an integrated sphere. The values of the estimated optical power using the proposed method and the integrated sphere equipped with a spectrometer were consistent with each other. The tested LED exhibited a high optical energy efficiency, reaching approximately η ≈ 30%. In addition, an uncertainty analysis of the obtained results was performed. Compact modelling based on a thermal resistor network (Rth) and a 3D-FEM analysis were performed to confirm the experimental results.