Thermal Skin Research Articles

Redox intensity and psychoemotional status of rats in burn skin injury

Relevance. Currently, the problem of regeneration of damaged skin, including of a burn nature, remains relevant. The work describes the results of the study of the redox intensity and of the psychoemotional status of rats in thermal skin injury. The aim of the study is an experimental study of the redox intensity and of the psychoemotional status of rats in burn skin injury. Materials and Methods. The study was conducted on nonlinear male rats of average weight 250 grams for 6-8 months. To assess psychoemotional status, studies were carried out using standard psychophysiological methods: «Open Field», «Elevated cruciform maze», «Suok Test» and «Porsolt.» The intensity of redox processes in the hypothalamic and prefrontal regions of the brain was assessed by determining the intensity of lipid peroxidation and catalase activity. The activity of lipid peroxidation was determined by the initial content of malonic dialdehyde, as well as by the rate of spontaneous and ascorbic peroxidation of lipids. Results and Discussion. During the study, it was found that burn damage to the skin was accompanied by an increase in the concentration of TBC-active products of lipid peroxidation in the hypothalamic and prefrontal regions of the brain of rats, which resulted in the development of oxidative stress. Burn injury initiated peroxidation processes in the studied areas of the brain, the most pronounced in the early period of the burn process (on days 2-4), with varying degrees decreasing in the following periods (on days 7, 10). The results of the assessment of the psychoemotional status of animals in burn skin injury in standard behavioral tests confirm the involvement of the nervous system in response to stress, the reflex activity of which under stressful conditions manifests itself in a change in behavioral reactions. In the conditions of burn damage to the skin, signs of an alarming-depressive state, in particular disorientation in space, suppression of the psychoemotional state, and a change in the nature of behavioral reactions were noted. Conclusion. Thus, the revealed changes in the intensity of redox processes and the peculiarities of the psychoemotional status of rats in burn skin damage are the result of biochemical and functional disorders of the brain, activated during protective and adaptation reactions in burn injury.

Distribution of Vernix Caseosa and Associated Factors Among Newborns Delivered at Adama Comprehensive Specialized Hospital Medical College, Ethiopia, in 2022: Cross-Sectional Study.

Vernix caseosa is a complex proteolipid material synthesized partly by fetal sebaceous glands during the last trimester of pregnancy. Understanding the structure and function of newborn skin is crucial for determining optimal thermal support, infection control, and skin moisturization. So far, in Ethiopia, there is no research done related to the distribution of vernix caseosa and associated factors on newborn skin. Doing such research could give awareness about factors associated with the distribution of vernix caseosa on newborns' skin and to take necessary protective measures for those that may be affected. The objective of this study is to assess the distribution of vernix caseosa and associated factors among newborns delivered at Adama Comprehensive Specialized Hospital Medical College from November to December 1, 2021. Hospital-based cross-sectional study design was conducted from November to December 1, 2021 at Adama Comprehensive Specialized Hospital Medical College (ACSHMC). Four hundred twenty-two eligible newborns were selected by a systematic sampling method. Data were collected by four data collectors by using a pretested questionnaire. The distribution of vernix caseosa on the different regions of the neonate was assessed, by exposing their whole body for a minute. Data entry was done by EPI data version 4.6 and analyzed by using SPSS version 25. A logistic regression of P-value of <0.25 during bivariate and P < 0.05 during multivariate analysis at a 95% confidence level was considered statistically significant. Out of 422 study participants 231 (54.7%) with 95% CI (49.8, 59.8) babies had vernix caseosa. Being primiparous with (AOR = 1.9, PV = 0.013, 95% CI: 1.141, 2.92), being multiparous with (AOR = 1.98, PV = 0.04, CI: 1.29, 3.225), being females with (AOR = 2.1, PV = 0.001, CI: 1.39, 3.18), being preterm with (AOR = 2.98, PV = 0.036, 95% CI: 1.08, 10.72), non-diseased newborns with (AOR = 1.6, PV = 0.046, 95% CI: 1.07, 2.7) were identified as associated factors for the distribution of vernix caseosa on the newborn skin. This study showed that the distribution of vernix caseosa on the skin of the newborns was associated with parity, sex, gestational age, and absence of disease.

Study of pedestrians’ mixed thermal responses when experiencing rapid and simultaneous variations in sun and wind conditions in urban continuums

• Subjects experienced different intensities of variations in wind and solar radiation while walking in urban areas; • A novel index to characterize the variation; • Transient physio-psychological responses to variations were recorded; • Influences of simultaneously varying wind and solar radiation were explored; • Intensity of simultaneous variations was quantified by skin temperature variability; • Intensifying simultaneous variations can increase the thermal acceptability. Rich, rapid, and simultaneous variations in wind and solar radiation produced by complex urban continuums are supposed to have positive effects on thermal comfort during walking. However, the identification of these influences is still challenging. In view of this, this study observed the mixed thermal perceptions and skin temperature of 70 healthy young college students when strolling in two complex urban continuums and experiencing rapid variations in sun and wind conditions. An index was proposed to categorize the varying wind and solar radiation in both numerical and geometrical respects. The results showed that, the intensities of varying wind, varying solar radiation, and air temperature simultaneously influenced the mixed thermal perceptions. Meanwhile, the intensity of simultaneously varied wind and solar radiation can be quantified by the mean skin temperature variability in a multiple linear model. An increase in the intensity of simultaneously varied wind and solar radiation led to a two-degree rise in the acceptable air temperature and a 1.2-degree increase in the mean skin temperature threshold for irritation. The study revealed the effects of simultaneously varied wind and solar radiation on pedestrian thermal comfort, motivating urban planners to take advantage of the dynamic nature created by urban morphologies to generate wind and solar radiation variations for comfort.

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.

Study on the influence of hypobaric hypoxia on human thermal comfort under step change thermal environments

Given the meteorological conditions on the Tibetan plateau such as low temperatures and large diurnal range, people moving in and out of buildings are inevitably exposed to the transient, step change thermal environments. Significant temperature changes are closely related to humans' thermoregulatory processes, and the hypoxic environment may affect the thermoregulation process of sojourners in Tibet, which makes it difficult for people to adapt to temperature changes in time and increases the risk of disease. Nevertheless, most experimental studies on temperature step change were carried out in plain. Only a few experimental studies focused on the effect of temperature step change on human thermal comfort under low temperature and hypoxic environment. In order to understand the impact of this condition, the same temperature step change experiment was conducted in Xi'an and Lhasa, respectively. The results showed that the hypoxic environment of the plateau could cause decreasing of sojourners’ thermal sensation and skin temperature in Tibet under low temperature environment, and prolong the time needed for skin to rewarm. The results of this study can help provide a better thermal environment in buildings to ensure the health and thermal comfort of Tibetan sojourners.

A modified method of the standard effective temperature (SET) based on the extended mean skin temperature index (EMSTI)

Among the existing thermal environment evaluation indexes, the standard effective temperature (SET) is based on the two-node model and performs better than the predicted mean vote (PMV) in non-neutral environments. However, previous studies show that the mean skin temperature and skin wettedness of the SET standard environment do not equal to the actual value, which violates the premise of SET. Moreover, it is found that the mean skin temperature of the standard environment differs from the actual value significantly under high temperature and humidity. Therefore, the applicability of SET in hot and humid environments deserves further study. The mean skin temperature is a superior evaluation index of thermal sensation in steady-state thermal environments with moderate temperature and humidity, and has been widely used in thermal sensation prediction. However, there also lacks in-depth research on the relationship between thermal sensation and mean skin temperature under high temperature and humidity. In this study, an extended mean skin temperature index (EMSTI) based on mean skin temperature combined with the maximum latent heat loss from skin surface is proposed through theoretical derivation. By verifying the index using the experimental data from different laboratories, it is shown that the proposed EMSTI can well evaluate the thermal sensation of hot and humid environments in different areas. The EMSTI is further used to represent thermal sensation to establish the equivalent relationship between the standard and actual environment, and the SET in hot-humid areas is modified.

Surface temperature characteristics of underwater thermal jet based on thermal skin

In this study, the effect of underwater thermal jet on the thermal skin of water surface were conducted by experiments. The parameters, such as the Reynolds number, underwater depth, disturbance degree of the propeller, and the temperature difference between the thermal jet and ambient water, on the temperature distribution of the water thermal skin were analyzed. The results demonstrate that the infrared signal of the water surface is mainly caused by the destruction of thermal skin structure but not the direct thermal signal generated by the buoyancy of the thermal wake. Moreover, the damage of the thermal skin is closely related to the flow field of the lower water column. As the depth of the underwater jet increases, the greater the temperature difference between the jet and ambient water, the larger is the area of temperature signal generated by the water surface, with a positive correlation between them. When the depth of the hot jet under the action of the thruster is small (d/D<0.36Fr), the structure of cooling water is unstable during its rising due to the inhibition of water surface. This, has a random effect on the infrared signal of the water surface. This study could provide experimental support for revealing the mechanism of infrared characteristics at water surface caused by the buoyancy of underwater thermal jet.

Occupant’s thermal comfort in a radiant ceiling cooling room with hot wall surface

A radiant ceiling cooling (CC) system integrated with a mechanical ventilation system was extensively applied in a modern office in a glass curtain wall building. Thermal comfort in a radiant ceiling cooling room with mixing ventilation (MV) or underfloor air distribution (UFAD) was investigated by objective measurements and subjective questionnaires. The external wall surface temperature and mean radiant temperature were 33.9–34.6°C and 27.2–27.4°C, respectively, with a heat transfer of 41.5 W/m2 from the external wall and 37.8–38.6°C and 27.4–28.2°C with a heat transfer of 69.5 W/m2 from the external wall. The indoor air velocity in the occupied zone was 0.17–0.23 m/s in the room with CC+MV and 0.09–0.16 m/s in the room with CC + UFAD. There was a considerable difference between occupants’ thermal perceptions with different distances away from the external wall. Both the ventilation system type and hot wall surface temperature did not influence occupants’ overall thermal perceptions, but their local thermal sensation and skin temperature. The results suggest that the impacts of ventilation system type and hot wall surface temperature on occupants’ local thermal response should be considered during the design of a radiant ceiling cooling system combined with a mechanical ventilation system.

Radiative Hybrid Ferrofluid Flow Over a Permeable Shrinking Sheet in a Three-Dimensional System

Due to the significance of magnetic nanofluids in environmental and biomedical sectors, this study is designed to analyze the available solutions alongside with the flow and thermal behaviours of radiative hybrid ferrofluid flow in a three-dimensional system subjected to the shrinking surface. The case of Fe3O4-CoFe2O4/water is considered in this work. The initial procedure is conducted by reducing the complex model into a system of nonlinear differential equations using similarity transformation technique. The results are generated using the bvp4c package in the Matlab software and graphically presented. The existence of dual solutions leads to the treatment of stability analysis where the first solution is affirmed as the physical solution. Meanwhile, the impact of thermal radiation, magnetic field and suction are also observed for the distributions of thermal rate and skin friction coefficients. These distributions boost with the imposition of magnetic field and suction while a deterioration in thermal rate is observed with the rise of thermal radiation.

High heat storing and thermally diffusive artificial skin for wearable thermal management

Thermal management for wearable devices is of great importance since heat generation from electronic devices can cause adverse effects such as skin burns and malfunctioning of the devices. Here, we present an advanced thermal skin (ATS) based on a hybrid structure that exhibits both high thermal diffusivity and thermal storage capability. Silver flake/polydimethylsiloxane (PDMS) serpentine structure (SPS) and sodium-acetate-based hydrogel matrix (SAHM) form an interfacial layer between the skin and wearable device not only to thermally protect the skin but also to prevent the device from malfunctioning by absorbing the heat released from the device. The high thermal diffusivity of SPS serves to spread the heat, while the high thermal storage capability of SAHM facilitates heat absorption without a significant temperature increase. Unlike the general phase change materials (PCMs), SAHM retains a small modulus change of 4.8 fold while maintaining comparable heat capacity to paraffin. Such a skin-like softness of ATS regardless of its phase has not yet been reported elsewhere to the authors’ best knowledge. This property enables conformal contact with the deformable surface and increases its applicability to wearable thermal management, and in this regard, we expect that this study will make significant contributions to the heat management of future wearables.

7723 Adverse Events Using Advanced Sealing Devices during Vaginal Hysterectomy: An Analysis of the Maude Database

<h3>Study Objective</h3> To identify visceral injuries associated with the use of advanced sealing devices at the time of vaginal hysterectomy. <h3>Design</h3> Retrospective review. <h3>Setting</h3> Analysis of the Manufacturer and User Facility Device Experience (MAUDE) database for reported visceral injuries from 11/1/1990 – 11/1/2021. <h3>Patients or Participants</h3> MAUDE was queried for the Brand Name ‘LigaSure Impact' and ‘ENSEAL x1' and Event Type ‘Injury' associated with vaginal hysterectomy. Two individuals independently reviewed events identified. <h3>Interventions</h3> N/A. <h3>Measurements and Main Results</h3> A total of 102 events were recorded. Following removal of duplicate entries, there were a total of 92 reports of injury [LigaSure Impact n=50, ENSEAL x1 n=42]. Of these reports, 29 were during hysterectomy of all types [LigaSure Impact: 11/50 (22%), ENSEAL x1: 18/42 (43%)], of which 9 were during vaginal hysterectomy [LigaSure Impact: 4/11 (36%), ENSEAL x1: 5/18 (28%)] including 2 thermal skin injuries, 1 ureteral injury, 1 bladder injury and 5 unspecified injuries attributed to device malfunction. No bowel injuries were identified. <h3>Conclusion</h3> Thermal injury is a rare but important complication associated with use of advanced sealing devices during vaginal hysterectomy. Vaginal surgeons must be aware of this potential adverse outcome and remain vigilant in preventing it.

Dynamic thermal perception under whole-body cyclical conditions: Thermal overshoot and thermal habituation

The emerging “smart grid” paradigm with associated demand-management programs, such as demand-response (DR), calls for enhanced building energy flexibility. This can be achieved by time-shifting or -shaving building heating and cooling peak loads through the implementation of heating and cooling set-point temperature modulations. However, designing and controlling comfortable DR-induced set-point variations remains a challenge as the psycho-physiology of dynamic thermal perception is still poorly understood. In this paper, we explored the physiological and subjective responses of 29 male and 35 female adults to whole-body warm and cool cyclical thermal conditions and focused on studying the phenomena of “thermal overshoot” and “thermal habituation”. We observed that females responded to cooling with a higher rate of cooling of skin temperature and, correspondingly, stronger thermal overshoot responses compared to males. These perceptual differences were explained in terms of skin temperature differences since the relationship between thermal sensation and skin temperature was independent of sex. We tested whether other factors influence the interindividual variability of the sensory response and found that the thermal overshoot response weakens as participants' body mass index increases and their age decreases. Thermal habituation was found to modify skin temperature only after cool exposures. Given that the studied rates of change of the air temperatures are those that can be typically found in buildings during DR events, our results can have implications on the design and control of female-proofed set-point fluctuations, as designing for an average occupant might result in thermally unacceptable conditions for females.

Autonomic thermoregulatory responses and subjective thermal perceptions upon the initiation of thermal behavior among resting humans in hot and humid environment

BackgroundWhile thermoregulatory behavior is critical for maintaining homeostasis, our knowledge of behavioral thermoeffectors in humid heat is limited compared to the control of autonomic thermoeffectors. The predictions that the frequency and duration of intensified humid heat events are expected to increase in the coming years underline this shortcoming. Therefore, this study aims to elucidate the activation of autonomic thermoregulatory responses and subjective thermal perceptions upon deciding to initiate thermal behavior in a hot and humid environment.MethodsTen young male adults participated in an experimental trial where local cooling was permitted at any time during the behavioral assessment during passive exposure to humid heat. The air temperature and relative humidity were kept at 33^{circ }C and 80%, respectively. Skin temperatures, core body temperature (T_{text {core}}), and skin blood flow (forearm, upper arm, and upper back) were obtained 120 s preceding thermal behavior. Local sweat rate (forearm and upper arm) and subjective thermal perceptions (neck and whole-body) upon thermal behavior initiation were also recorded.ResultsMean skin temperature ({overline{mathrm {T}}}_{text {sk}}) and T_{text {core}} increased prior to thermal behavior initiation (p= 0.002; p= 0.001). An increase in mean body temperature ({overline{mathrm {T}}}_{text {body}}) was also observed (p < 0.001). However, the initiation of thermal behavior is not preceded by an increase in skin blood flow (pge 0.154) and local sweat rate (pge 0.169). An increase in thermal discomfort and skin wetness perception was observed (ple 0.048; ple 0.048), while thermal sensation did not differ from the baseline (pge 0.357).ConclusionThese findings suggest that when given the opportunity to behaviorally thermoregulate in a hot and humid environment, changes in skin blood flow and sweat rate are not required for thermal behavior to be initiated in resting humans. Moreover, an increase in {overline{mathrm {T}}}_{text {sk}} and T_{text {core}}, which appears to cause an increase in thermal discomfort, precedes thermal behavior. In addition, an increase in {overline{mathrm {T}}}_{text {body}} leading up to thermal behavior initiation was observed, suggesting that changes in {overline{mathrm {T}}}_{text {body}} rather than {overline{mathrm {T}}}_{text {sk}} and T_{text {core}} alone mediate thermal behavior in humid heat. Collectively, the results of this study appear to support the hypothesis that the temporal recruitment of autonomic thermoeffectors follows an orderly manner based on their physiological cost.

Thermal responses and skin temperature to moderate temperature ramps in winter: An office-lab study

In order to explore the acceptable temperature limits of humans in temperature ramps by intermittent heating in the north China, the research was conducted in an office-lab. Four indoor dynamic heating environments with different initial temperatures (15–18 °C) and change rates (0.02–0.18 °C/min) were created. The room temperature gradually rose as people entered the room and divided into two phases by the ramping rates, which was fast in the first phase. During the filed experiments, the variations of overall and local thermal responses were investigated while environmental parameters was monitored. Additionally, the local skin temperatures of participants' hand and ankle were also recorded.The results indicated that the variations of skin temperature from different exposed parts were different. It indicated that humans can make active physiological adjustments according to environmental changes. Moreover, the subject's thermal responses were lagging and affected by the thermal experience. The thermal sensation vote (TSV) was statistically different between the two phases. The calf was the most significant factor on the overall thermal sensation. Furthermore, the TSV significantly affected other psychological responses. The relationships between the TSV and other thermal responses were observed. The thermal sensation evaluation models were established.In summary, the indoor temperature of 16–18 °C is recommended as the initial temperature when the temperature ramping rate is less than 0.2 °C/min. This study gives a theoretical guide for the creation of dynamic indoor thermal environments, which is beneficial for thermal comfort, health, and energy saving.

Discussion on inapplicability of Universal Thermal Climate Index (UTCI) for outdoor thermal comfort in cold region

The Universal Thermal Climate Index (UTCI) is one of the commonly used thermal indices to evaluate outdoor thermal comfort. In order to explore its applicability in cold regions, UTCI was compared with the Physiological Equivalent Temperature (PET) and outdoor air temperature (Ta) simultaneously. And the internal mechanism relationship between UTCI and outdoor environmental parameters were explored. The results showed that UTCI, PET, Ta had a good linear relationship with outdoor human thermal sensation. The probability of correct interpretation for outdoor thermal comfort was 74.2%, 75.1%, 80.1%, respectively. UTCI may have an invalid interval under its low-temperature zone in cold region. With the decrease of UTCI in the invalid interval will not affect the subjective thermal sensation and objective average skin temperature significantly. Taking Tianjin for example, the invalid interval of UTCI was approximately lower than −15 °C, which may be due to UTCI being very sensitive to the outdoor lower air temperature (approximately lower than 0 °C) and higher wind speed (approximately above 8 m/s). This study does not recommend UTCI as an evaluation index for outdoor thermal comfort in cold and severe cold regions in winter.

Infrared thermal imaging-based skin temperature response during cupping at two different negative pressures

Cupping therapy can relieve muscle fatigue and pain after exercise by increasing blood flow at the treatment site, which may lead to dynamic changes of the local skin temperature. This study aimed to analyze the effect of cupping on local skin temperature under two different negative pressures using infrared thermography (IRT). Cupping therapy was performed on the forearms of 22 healthy subjects using the negative pressures of − 0.03 and − 0.04 MPa. IRT was used to record the dynamic changes in skin temperature before, during, and after cupping. Both cupping pressures induced a non-linear skin temperature response: temperature decreased first and then increased during cupping, while it first increased and then decreased after cupping. A significant difference was noted between the two negative pressure groups in the maximum temperature increment after cupping (P < 0.001). Compared with the basal temperature before cupping, the maximum increase in skin temperature after cupping in the − 0.03 and − 0.04 MPa groups was 0.92 and 1.42 °C, respectively. The findings of this study can lay the foundation evaluating the curative effect of cupping based on IRT and provide an objective reference for selecting the cupping negative pressure.

Influence Of Local Muscle Cooling On Mitochondrial Related Gene Expression At Rest

Our lab has demonstrated physiological and molecular differences between exercising in ambient cold and an application of local cold. Local cold application has been shown to decrease the temperature of the skin and muscle, causing vasoconstriction, and decreasing blood flow. Currently, the effects of local cold application independent of exercise on mitochondrial related gene expression is unknown. PURPOSE: To determine the impact of localized cooling to the skeletal muscle during rest. METHODS: Thermal wraps were applied to the vastus lateralis (VL) of each limb of 12 participants. One limb received a cold application (randomized) in the form of circulated 10 °C fluid (COLD), while the other did not (CON). Wraps were removed at the 4-hour time point and measurements of skin temperature, blood flow, and intramuscular temperature were collected. Muscle biopsies were taken from the VL of each leg for later molecular analyses. Statistical significance (p < 0.05) was analyzed via paired t-tests. RESULTS: Skin temperature, measured via laser thermometer, was lower in COLD (34.84 ± 0.94 °C, to 13.15 ± 0.99 °C, p < 0.01). Similarly, thermal camera skin temperature measurements were (35.75 ± 0.94 °C, to 12.81 ± 0.93 °C, p < 0.01). Intramuscular temperature, via hypodermic thermocouple, also was lower in COLD (35.57 ± 0.76 °C, to 20.54 ± 1.31 °C, p < 0.01) after cold application. Blood flow, measured via ultrasound equipped with a transducer, did not change (0.64 ± 0.12 cm/sec, to 0.62 ± 0.17 cm/sec, p = 0.450). Arterial diameter was lower in COLD after 4 h (0.62 ± 0.05 mm, to 0.60 ± 0.05 mm, p = 0.018). Molecular outcomes (gene expression) will be measured soon via RT-qPCR and analyzed using the 2-∆∆ct method. CONCLUSIONS: Mitochondrial related gene expression data will help interpret previous local cold and exercise findings. Supported by NE-INBRE, NIGMS Funding (P20GM103427).

Experimental evaluation of thermal comfort, SBS symptoms and physiological responses in a radiant ceiling cooling environment under temperature step-changes

People usually experience transient thermal environments when entering or leaving a conditioned indoor environment. This has been previously explored but there is little knowledge on the impact of temperature step-changes on thermal comfort in a radiantly cooled environment. We aim to investigate human comfort and underlying physiological mechanism in such conditions. We assessed thermal comfort, sick building syndromes (SBS) symptoms, and physiological responses. Twenty healthy participants were exposed to three temperature step-change conditions with three outdoor air temperatures (29 °C, 33 °C and 36 °C) and one indoor air temperature of 26 °C. Subjective evaluation was collected through a questionnaire. Blood oxygen saturation (SpO2), skin temperature, and electrocardiograph (ECG) were measured. As expected, the overall thermal sensation, comfort, acceptability, preference, and subjective air freshness changed significantly before and after temperature step-changes. Perceived sweat and chest tightness were also affected by the temperature step-changes. Skin temperature, heart rate, time-domain, and nonlinear heart rate variability were affected significantly under temperature step-changes. We observed the overshoot phenomenon with thermal sensation and subjective air freshness under temperature down-step. Thermal sensation had a faster stabilization time than the measured physiological parameters (i.e., skin temperature, heart rate and heart rate variability) under temperature step-changes. The stabilization time before starting a thermal comfort experiment should be at least 30 min. Thermal sensation and skin temperature had an asymmetry effect on temperature step-changes.

The effect of inhaled air temperature on thermal comfort, perceived air quality, acute health symptoms and physiological responses at two ambient temperatures.

We explored the importance of inhaled air temperature on thermal comfort, perceived air quality, acute non-clinical health symptoms, and physiological responses. Sixteen subjects stayed in a stainless-steel chamber for 90 min. They experienced four conditions with two inhaled air temperatures of 22 and 30°C and two ambient temperatures of 22 and 30°C in a 2 × 2 design. They wore breathing masks covering their mouth and nose to control the inhaled air temperature; the air was provided from an adjacent twin stainless-steel chamber. The subjects evaluated thermal conditions and health symptoms on visual-analogue scales. Skin temperature and electrocardiography were recorded. Whole-body thermal sensation and skin temperature did not change when the temperature of inhaled air was changed. Perceived air quality was significantly improved when subjects sat in the chamber at 30°C and inhaled air with a temperature of 22°C; under these conditions lip and throat dryness were significantly reduced. The lower inhaled air temperature increased time-domain heart rate variability indicators and decreased heart rate and the LF/HF ratio, suggesting that the parasympathetic nervous system was activated and the sympathetic nervous system was suppressed.

Adipose stromal vascular fraction: a promising treatment for severe burn injury.

Thermal skin burn injury affects both adults and children globally. Severe burn injury affects a patient's life psychologically, cosmetically, and socially. The pathophysiology of burn injury is well known. Due to the complexity of burn pathophysiology, the development of specific treatment aiding in tissue regeneration is required. Treatment of burn injury depends on burn severity, size of the burn and availability of donor site. Burn healing requires biochemical and cellular events to ensure better cell response to biochemical signals of the healing process. This led to the consideration of using cell therapy for severe burn injury. Adult mesenchymal stem cells have become a therapeutic option because of their ability for self-renewal and differentiation. Adipose stromal vascular fraction (SVF), isolated from adipose tissues, is a heterogeneous cell population that contains adipose-derived stromal/stem cells (ADSC), stromal, endothelial, hematopoietic and pericytic lineages. SVF isolation has advantages over other types of cells; such as heterogeneity of cells, lower invasive extraction procedure, high yield of cells, and fast and easy isolation. Therefore, SVF has many characteristics that enable them to be a therapeutic option for burn treatment. Studies have been conducted mostly in animal models to investigate their therapeutic potential for burn injury. They can be used alone or in combination with other treatment options. Treatment with both ADSCs and/or SVF enhances burn healing through increasing re-epithelization, angiogenesis and decreasing inflammation and scar formation. Research needs to be conducted for a better understanding of the SVF mechanism in burn healing and to optimize current techniques for enhanced treatment outcomes.