Effect of repeated topical capsaicin gel administration on oral thermal quantitative sensory testing: A two-arm longitudinal study.

OBJECTIVES: Few studies used thermal quantitative sensory testing to assess the effects of repeated capsaicin gel administration in the oral cavity. This study aimed to investigate thermal sensory and pain thresholds before and after repeated capsaicin gel administration. SUBJECTS AND METHODS: Ten healthy females (22 ± 2 years) applied a capsaicin gel on the gingival mucosa twice daily for 14 days, and heat pain threshold, warm detection threshold, cold pain threshold, and cold detection threshold were assessed on the oral mucosa. Measurements were performed before and after the 14 days and were compared to a control sample (n = 10, all females, 23 ± 3 years). RESULTS: Capsaicin increased heat pain threshold in the anterior maxilla by 2.9°C (95% CI: 1.6-4.2) (p < 0.001) and in the anterior mandible by 2.2°C (95% CI: 1.0-3.4) (p = 0.001), similar to warm detection threshold that increased by Δ1.1°C (95% CI: 0.3-1.9) (p = 0.009). No significant changes were found in the controls. CONCLUSIONS: These findings encourage the use of thermal quantitative sensory testing in the oral cavity to assess thermal sensation, which might be useful for assessing the effects of therapies aimed at reducing pain.

The thermal comfort of pedestrians in a humid subtropical climate according to different thermal perception ratings.

This study aims to evaluate agreement among subjective thermal comfort, thermal sensation, thermal perception, and thermal tolerance indices, according to pedestrians in downtown Santa Maria, southern Brazil, which has a humid subtropical climate (Cfa). Between August 2015 and July 2016 (three periods), 1728 questionnaires were applied. Evaluation of the dependence of statistical variables was based on gender and age, at three periods of time: August 2015 (864 respondents), January 2016 (432 respondents), and July 2016 (432 respondents). Statistical evaluation was based on Pearson's chi-square test using RStudio software, and a significance level (α) of 5% for thermal comfort, thermal sensation, thermal preference, and thermal tolerance was used. Results indicated that age and gender affect the relationship between the variables. Thermal comfort and thermal tolerance presented the best correlation and coherence, regardless of age or gender. This study contributes to knowledge on the local microclimate and can contribute to urban planning to implement strategies that improve pedestrians' thermal comfort.

Thermal-Adaptation-Behavior-Based Thermal Sensation Evaluation Model with Surveillance Cameras.

The construction sector is responsible for almost 30% of the world's total energy consumption, with a significant portion of this energy being used by heating, ventilation and air-conditioning (HVAC) systems to ensure people's thermal comfort. In practical applications, the conventional approach to HVAC management in buildings typically involves the manual control of temperature setpoints by facility operators. Nevertheless, the implementation of real-time alterations that are based on the thermal comfort levels of humans inside a building has the potential to dramatically improve the energy efficiency of the structure. Therefore, we propose a model for non-intrusive, dynamic inference of occupant thermal comfort based on building indoor surveillance camera data. It is based on a two-stream transformer-augmented adaptive graph convolutional network to identify people's heat-related adaptive behaviors. The transformer specifically strengthens the original adaptive graph convolution network module, resulting in further improvement to the accuracy of the detection of thermal adaptation behavior. The experiment is conducted on a dataset including 16 distinct temperature adaption behaviors. The findings indicate that the suggested strategy significantly improves the behavior recognition accuracy of the proposed model to 96.56%. The proposed model provides the possibility to realize energy savings and emission reductions in intelligent buildings and dynamic decision making in energy management systems.

Machine learning thermal comfort prediction models based on occupant demographic characteristics.

This study aims to investigate the predictive occupant demographic characteristics of thermal sensation (TS) and thermal satisfaction (TSa) as well as to find the most effective machine learning (ML) algorithms for predicting TS and TSa. To achieve this, a survey campaign was carried out in three mixed-mode buildings to develop TS and TSa prediction models by using six ML algorithms (Logistic Regression, Naïve Bayes, Decision Tree (DT), Random Forest (RF), K-Nearest Neighborhood (KNN) and Support Vector Machine). The prediction models were developed based on six demographic characteristics (gender, age, thermal history, education level, income, occupation). The results show that gender, age, and thermal history are significant predictors of both TS and TSa. Education level, income, and occupation were not significant predictors of TS, but were significant predictors of TSa. The study also found that RF and KNN are the most effective ML algorithms for predicting TS, while DT and RF are the most effective ML algorithms for predicting TSa. The study found that the accuracy of TS prediction models ranges from 83% to 99%, with neutral being the most correctly classified scale. The accuracy of TSa prediction models ranges from 84% to 97%, with dissatisfaction being the most common misclassification.

Effect of ice slurry ingestion on thermoregulatory responses during fixed-intensity cycling in humid and dry heat.

PURPOSE: This study examined the thermoregulatory response and ergogenic effects of ice slurry (ICE) ingestion in hot environments with high and low relative humidity (RH). METHODS: Eight males completed four trials in a crossover manner in dry (DRY: 34.7 ± 0.2 °C, 38 ± 2%RH) and humid heat (HUM: 34.8 °C ± 0.2 °C, 80 ± 1%RH). They ingested 8.0 g·kg-1 of ICE (0.0 °C) or 37.5 °C water (CON) during 30 min before exercise, and three aliquots (3.2 g·kg-1) of ICE or CON during 45-min cycling at 50%[Formula: see text]O2peak, followed by cycling to exhaustion at 80%[Formula: see text]O2peak (TTE). Body core temperature (Tcore), mean skin temperature (Tsk), heart rate (HR), thermal comfort, thermal sensation and rating of perceived exertion (RPE) were measured. RESULTS: Relative to CON, ICE improved TTE by 76.5 ± 96.5% in HUM and 21.3 ± 44.9% in DRY (p = 0.044). End-exercise Tcore was lower in ICE versus CON in DRY (37.8 ± 0.4 °C versus 38.1 ± 0.3 °C, p = 0.005) and HUM (38.8 ± 0.4 °C versus 39.3 ± 0.6 °C, p = 0.004). ICE decreased HR, heat storage and heat strain index only in DRY (p < 0.001-0.018). ICE improved thermal sensation and comfort in DRY and HUM (p < 0.001-0.011), attenuated RPE in HUM (p = 0.012) but not in DRY (p = 0.065). CONCLUSION: ICE tended to benefit performance in humid heat more than in dry heat. This is likely due to the reduced extent of hyperthermia in dry heat and the relative importance of sensory inputs in mediating exercise capacity.

Thermal perception and lung function: a panel study in young adults with exercise under high outdoor temperature.

It has been observed that high temperature exposure is associated with a reduction in lung function and some possible biological mechanisms have been suggested. However, it is unclear if thermal perception plays a role in the association. From September 3rd to 15th, 2018, in Guangzhou, China, we repeatedly measured daily thermal perception and lung function among 126 participants with outdoor military training. We performed a linear mixed model and stratified analyses by the origin of students, gender, and the training period to evaluate the effects of thermal perception on lung function. A total of 399 measurements were collected. Per vote increase in thermal sensation vote towards the "hot" direction was associated with a - 0.04 L (95% CI: - 0.08 to - 0.01) decrease in forced vital capacity (FVC), and - 0.04 L (95% CI: - 0.08 to - 0.01) decrease in forced expiratory volume in 1 s (FEV1). Per grade increase towards the "very uncomfortable" direction for thermal comfort vote was associated with an increased percentage of forced expiratory volume in 1 s (FEV1%) by 1.52% (95% CI: 0.18 to 2.86). For thermal preference, with preferred cooler vote increased by one level, FVC and FEV1 decreased by - 0.05 L/s (95% CI: - 0.08 to - 0.02) and - 0.05L/s (95% CI: - 0.08 to - 0.02), respectively. The effects of thermal perception on lung function were stronger among non-local and in the first week of training. Our study suggests that in the same high-temperature environment, thermal perception is associated with lung function, even in healthy adults.

Effect of air blowing inside isolated hospital clothing on perceptual and physiological heat strain in laboratory conditions.

Heat stress is one of the most common complaints of health care employees who wear isolation gowns to protect themselves from biological agents, particularly during the warmer seasons. This study was conducted in a climatic chamber to determine the influence of airflow within isolated hospital gowns on physiological-perceptual heat strain indices. The experiment was conducted in three trials: regular clothes (CON), an impenetrable gown without air blowing (GO), and a gown with air blowing (GO + FAN) at temperature conditions of 27 °C and 25% relative humidity (RH). During the trial, physiological-perceptual response data were recorded for a half-hour on a treadmill at a speed of km/hr and a slope of 0% activity at 5-min intervals. The ASHRAE Likert scale was used to assess thermal comfort (TC), thermal sensation (TS), and skin wetness sensation (WS). As the results show, there was a significant difference in mean scores for TC and WS in both sexes when working in the CON, GO, and GO + FAN groups (P < 0.001). In women, the mean scores for TS, TC, and WS reduced considerably (P < 0.001) in the GO and GO + FAN in the amount of 10 and 12 CFM (20 [Formula: see text]/h), but in males, there was a statistically significant difference between mean scores (P < 0.001) in the GO + FAN at 12 CFM (20 [Formula: see text]/h) and 14 CFM (24 [Formula: see text]/h). Also, the greatest difference between the average heart rate, chest temperature, and temperature inside the clothes in women and men in the trials GO and GO + FAN was observed in the air flow 12 CFM and 14 CFM, respectively (P < 0.001). The usage of an air blower in isolated hospital clothes has been shown to influence physiological-perceptual parameters in men and women substantially. The existence of airflow in these gowns can improve safety, performance, and thermal comfort while also decreasing the risk of heat-related disorders.

Correlations among Firing Rates of Tactile, Thermal, Gustatory, Olfactory, and Auditory Sensations Mimicked by Artificial Hybrid Fluid (HF) Rubber Mechanoreceptors.

In order to advance the development of sensors fabricated with monofunctional sensation systems capable of a versatile response to tactile, thermal, gustatory, olfactory, and auditory sensations, mechanoreceptors fabricated as a single platform with an electric circuit require investigation. In addition, it is essential to resolve the complicated structure of the sensor. In order to realize the single platform, our proposed hybrid fluid (HF) rubber mechanoreceptors of free nerve endings, Merkel cells, Krause end bulbs, Meissner corpuscles, Ruffini endings, and Pacinian corpuscles mimicking the bio-inspired five senses are useful enough to facilitate the fabrication process for the resolution of the complicated structure. This study used electrochemical impedance spectroscopy (EIS) to elucidate the intrinsic structure of the single platform and the physical mechanisms of the firing rate such as slow adaption (SA) and fast adaption (FA), which were induced from the structure and involved the capacitance, inductance, reactance, etc. of the HF rubber mechanoreceptors. In addition, the relations among the firing rates of the various sensations were clarified. The adaption of the firing rate in the thermal sensation is the opposite of that in the tactile sensation. The firing rates in the gustation, olfaction, and auditory sensations at frequencies of less than 1 kHz have the same adaption as in the tactile sensation. The present findings are useful not only in the field of neurophysiology, to research the biochemical reactions of neurons and brain perceptions of stimuli, but also in the field of sensors, to advance salient developments in sensors mimicking bio-inspired sensations.

Gender differences in thermal sensation and skin temperature sensitivity under local cooling.

Local cooling has proven to be an alternative to traditional comfort air conditioning to ensure users' thermal comfort while conserving energy. Few studies have investigated the gender differences in the applicable cooling temperatures and the applicable cooling locations and the differences in the sensitivity of skin temperature to thermal sensation under local cooling. Based on the design of orthogonal experiment, nine chamber experiments were conducted through different combinations of ambient temperature, cooling temperature, and cooling location. The subjective questionnaires and objective measurements were obtained in each experimental case. The results showed that the ambient temperature and the cooling location significantly affect the human overall thermal sensation of both genders under local cooling, while cooling temperature and cooling location significantly affect the local thermal sensation. For female, a neutral thermal sensation can be achieved by cooling the back at 24-26 °C when the ambient temperature is 31 °C. Back cooling at 22-26 °C is effective for male when the ambient temperature is 28 °C and 31 °C, and sole cooling with a higher cooling temperature is more acceptable at 34 °C. Moreover, female skin temperature is more sensitive to thermal sensation than that of males under local cooling. The upper arm skin temperature is most sensitive to thermal sensations for female, while the forearm skin temperature is most sensitive for male.

Cutaneous warmth and hotness thresholds to radiation heat exposure at a distance of 10 cm from 17 body regions.

The purpose of the present study was to evaluate body regional differences in cutaneous warmth and hotness thresholds in relation to radiant heat exposure. Fourteen male subjects participated in this study (age: 25 ± 5 y, height: 176.6 ± 5.5 cm, body weight: 70 ± 5.8 kg). Cutaneous warmth and hotness thresholds were measured on the forehead, neck, chest, abdomen, upper back, lower back, upper arm, forearm, palm, back of hand, front thigh, shin, top of foot, buttock, back thigh, calf, and sole. The forehead (34.8 ± 0.2 °C), lower back (34.1 ± 1.2 °C) and palm (34.3 ± 0.7 °C) had the highest warmth thresholds, whereas the foot (29.8 ± 1.9 °C) and sole (28.0 ± 2.1 °C) had the lowest values among the 17 regions (P<0.001). Higher warmth thresholds were related to higher initial skin temperatures (Tsk) (r=0.972, P<0.001). Increases in Tsk for detecting warmth sensation were smaller for the lower back with a rise of 0.2 ± 0.4 °C and the abdomen (0.3 ± 0.3 °C) than for the buttock (0.9 ± 0.8 °C) and sole (0.8 ± 0.6 °C) (P<0.05). Increases in Tsk for detecting hotness sensation ranged from 0.5 to 1.5 °C. Warmth and hotness thresholds on the abdomen or sole had significant relationships with body mass index, indicating that the overweight are less sensitive to detecting radiant heat on the abdomen or sole. Thermal thresholds from radiant heat exposure of 100 cm2 were lower than the values from conductive heat exposure of 6.25 cm2, which might be explained by the effect of spatial summation.