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Introduction Passive heat treatment has been suggested to improve glycemic control in individuals with type 2 diabetes mellitus (T2DM). Previous studies have focused predominantly on hot water immersion and traditional sauna bathing, as opposed to the more novel method of infrared-based sauna bathing. Here, the impact of a single infrared sauna session on post-prandial glycemic control was assessed in older individuals with T2DM. Methods In this randomized controlled crossover trial, 12 participants with T2DM (male/female: 10/2, age: 69±7 y, BMI: 27.5±2.9 kg/m2) rested in an infrared sauna twice: once in a heated (60°C) and once in a thermoneutral (21°C) condition for 40 min, immediately followed by a 2-h oral glucose tolerance test (OGTT). Venous blood samples were obtained to assess plasma glucose and insulin concentrations and to determine the whole-body composite insulin sensitivity index. Results Body core and leg skin temperature were higher following the heated condition compared to the thermoneutral condition (38.0±0.3 vs. 36.6±0.2°C and 39.4±0.8 vs. 31.3±0.8°C, respectively; P<0.001 for both). The incremental area under the curve (iAUC) of plasma glucose concentrations during the OGTT was higher after the heated condition compared to the thermoneutral condition (17.7±3.1 vs. 14.8±2.8 mmol/L/120 min; P<0.001). No differences were observed in plasma insulin concentrations (heated: 380±194 vs. thermoneutral: 376±210 pmol/L/120 min; P=0.93) or whole-body composite insulin sensitivity indexes (4.5±2.8 vs. 4.5±2.1; P=0.67). Conclusions A single infrared sauna session does not improve postprandial blood glucose handling in individuals with T2DM. Future studies should assess the effect of more prolonged application of infrared sauna bathing on daily glycemic control. [ABSTRACT FROM AUTHOR]

Passively elevating body temperature can trigger a potentially beneficial acute inflammatory response. However, heat therapy often causes discomfort and negative thermal perceptions, particularly in females who generally have lower heat tolerance than males. This study aimed to evaluate the impact of facial cooling on thermal comfort and interleukin-6 concentration in response to 60 minutes of dry heat exposure, and to investigate sex differences in physiological responses and perceptions. 22 healthy young adults (10 females, 12 males; age: 24.4 ± 3.3 years) completed three trials in randomized order using a dry sauna device: 1) Hyperthermia (71.1 ± 1.9°C; HEAT), 2) Hyperthermia with facial cooling via fans (71.1 ± 3.0°C; FAN), and 3) Normothermia (27.0 ± 0.9°C; CON). Blood samples to determine interleukin-6 (IL-6) plasma concentration were collected before and after exposure; basic affect and thermal comfort, rectal and skin temperature were assessed throughout the intervention. Rectal temperature following HEAT (38.0 ± 0.3°C) and FAN (37.8 ± 0.3°C) did not differ between males and females (p = 0.57). Females had higher forehead skin temperatures than males (p ≤ 0.019). Thermal comfort remained more positive in FAN compared to HEAT (p ≤ 0.002). Females felt more thermal discomfort than males in HEAT (p ≤ 0.03), but not in FAN (p = 0.28). The increase in IL-6 plasma concentration was similar between HEAT and FAN (p = 1.00), and higher than CON (p ≤ 0.02); there was no difference between males and females (p = 0.69). This study showed that facial cooling alleviated the thermal discomfort during heat exposure, particularly benefitted females, and did not impede the acute IL-6 response. [ABSTRACT FROM AUTHOR]

Individuals are easily threatened by heat stress or hypothermia in outdoor environments. Therefore, there is a pressing necessity for thermal regulation materials capable of adapting to temperature shocks. Herein, an aerogel‐functionalized textile as a passive thermal regulator (AT‐PTR) is designed and demonstrated, comprising a heating side composed of carbon nanotube‐modified cotton fabric and a cooling side built of silica aerogel‐functionalized poly(vinylidene‐co‐hexafluoropropene) P(VdF‐HFP) nanofibers. The AT‐PTR demonstrates exceptional solar absorption on the heating side, achieving a warming performance of 23.2 °C in cold winter. On the cooling side, its high solar reflectance and infrared emissivity facilitate a sub‐ambient cooling effect of 12.7 °C during hot summer. Moreover, outdoor field tests of the AT‐PTR conducted across various regions and seasons demonstrate an all‐seasonal outdoor human thermal management capability. Additionally, the AT‐PTR exhibits outstanding wind‐proof and moisture permeability, and heat flow can be simply attained by flipping the AT‐PTR, ensuring sustained thermal comfort for individuals across various environments. [ABSTRACT FROM AUTHOR]

Combat sports athletes often undergo rapid body mass loss (BML), which presents health risks. Hydration testing has been proposed as a possible solution to reduce or eliminate rapid BML. However, combat sports athletes may exhibit distinct physiological characteristics due to repeated exposure to BML. Thus, traditional and emerging hydration biomarkers should be investigated to determine their potential suitability for field use in this cohort. This study examined whether BML can explain changes in serum and urine osmolality (SosmΔ, UosmΔ), tear osmolarity (TosmΔ), hematocrit (HctΔ), and urine‐specific gravity (USGΔ) after mild–moderate passive dehydration. Biomarker reliability was also assessed across two trials. Fifteen male and female combat sports athletes (age: 26.3 ± 5.3 years, body mass: 67.7 ± 9.9 kg) underwent a sauna protocol twice (5–28 days apart) aiming for 4% BML. The average BML in Trials 1 and 2 was 3.0 ± 0.7%. Regression analysis revealed that BML explained HctΔ (R2 = 0.22, p = 0.009) but not SosmΔ (R2 = 0.11, p = 0.079) or other biomarkers. Intraclass correlation coefficients (ICCs) were significant for all biomarkers except TosmΔ (ICC = 0.06, p = 0.37) and post‐Tosm (ICC = 0.04, p = 0.42); post‐Hct performed best (ICC = 0.82, p < 0.001). Contingency tables with post‐Sosm (295 mOsm/kg) and post‐USG (1.020) cutoffs revealed an 80% true negative rate (TNR) and a 62% true positive rate (TPR). Increasing the Sosm cutoff to 301 mOsm/kg decreased the TNR to 52% but increased the TPR to 83%. Although blood parameters were most sensitive to BML, they could only explain 11%–22% of biomarker variation. The typical USG cutoff misclassified 42% of athletes postdehydration, and reliability was generally poor‐moderate. Alternative strategies should be pursued to manage rapid BML in combat sports. [ABSTRACT FROM AUTHOR]

Air-source heat pumps (ASHPs), as an active device, are widely used in building heating and cooling processes. However, in severe cold regions, they face reduced heating efficiency and frosting problems in winter. This paper proposes a new heating solution by coupling an ASHP with passive heating systems. It combines an ASHP with passive sunrooms and heat storage systems for heating. Through software simulations and mathematical modeling, the new scheme is compared and analyzed against traditional ASHP solutions to explore the performance of this scheme in rural houses in severe cold regions of China during winter. According to simulation and calculation analysis, on the coldest day of winter, the coupling scheme can provide approximately 99.41 kWh of heat to the indoors, which exceeds the 86.67 kWh required to maintain an indoor temperature of 20 °C. The system's power consumption is 36.96 kWh, which is 66.88% lower than that of traditional heat pump heating. The study shows that the coupling system of an ASHP and passive heating has a good heating effect in severe cold regions. For the situation of insufficient solar energy at night, the design of phase-change materials and heat storage media can meet heating needs throughout the day. [ABSTRACT FROM AUTHOR]

Pre-exercise passive heating attenuates muscle damage caused by eccentric exercise in rats where the induction of heat shock proteins (HSPs) confers a myoprotective effect. We investigated whether pre-exercise hot water immersion (HWI) confers similar benefits in humans. Eleven recreational male athletes were immersed in 41°C water up to 60 min or until rectal temperatures reached 39.5°C. After a 6 h rest, the participants performed an eccentric downhill run for 1 h at −4% gradient to induce muscle damage. An endurance capacity test at 75% VO2max was conducted 18 h later. The control trial was similar except that participants were immersed at 34°C. Blood samples were collected to assess HSPs levels, creatine kinase, and lactate dehydrogenase activities. Plasma eHSP70 was higher post-immersion in HWI trials (1.3 ± 0.4 vs 1.1 ± 0.4; p = 0.005). Plasma eHSP27 was higher before (p = 0.049) and after (p = 0.015) endurance test in HWI. Leukocytic p-HSP27 was increased 18 h after HWI (0.97 ± 0.14 vs 0.67 ± 0.11; p = 0.04). Creatine kinase and lactate dehydrogenase activities were increased by 3-fold and 1.5-fold, respectively, after endurance test in HWI but did not differ across trials (p > 0.05). Mean heart rates were higher during eccentric run and endurance test in HWI as compared to control (p < 0.05). Endurance capacity was similar between trials (57.3 ± 11.5 min vs 55.0 ± 13.5 min; p = 0.564). Pre-exercise heating increased the expression of plasma eHSPs and leukocytic p-HSP27 but did not reduce muscle damage nor enhance endurance capacity. [ABSTRACT FROM AUTHOR]

Objective: We examined sex‐specific microvascular reactivity and hemodynamic responses under conditions of augmented resting blood flow induced by passive heating compared to normal blood flow. Methods: Thirty‐eight adults (19 females) completed a vascular occlusion test (VOT) on two occasions preceded by rest with or without passive heating in a randomized, counterbalanced order. Skeletal muscle tissue oxygenation (StO2, %) was assessed with near‐infrared spectroscopy (NIRS), and the rate of desaturation and resaturation as well as maximal StO2 (StO2max) and prolonged hypersaturation (area under the curve, StO2AUC) were quantified. Before the VOT, brachial artery blood flow (BABF), vascular conductance, and relative BABF (BABF normalized to forearm lean mass) were determined. Sex × condition ANOVAs were used. A p‐value ≤.05 was considered statistically significant. Results: Twenty minutes of heating increased BABF compared to the control (102.9 ± 28.3 vs. 36.0 ± 20.9 mL min−1; p <.01). Males demonstrated greater BABF than females (91.9 ± 34.0 vs. 47.0 ± 19.1 mL min−1; p <.01). There was no sex difference in normalized BABF. There were no significant interactions for NIRS‐VOT outcomes, but heat did increase the rate of desaturation (−0.140 ± 0.02 vs. −0.119 ± 0.03% s−1; p <.01), whereas regardless of condition, males exhibited greater rates of resaturation and StO2max than females. Conclusions: These results suggest that blood flow is not the primary factor causing sex differences in NIRS‐VOT outcomes. [ABSTRACT FROM AUTHOR]

Purpose: Soccer substitutes are exposed to periods of limited activity before entering match-play, likely negating benefits of active warm-ups. This study aimed to determine the effects of using a passive heat intervention following a pre-match, and half-time warm-up, on muscle and core temperature in soccer players during ambient (18 °C) and cold (2 °C) conditions. Methods: On four occasions, 8 male players, completed a pre-match warm-up, followed by 45 min of rest. Following this, participants completed a half-time re-warm-up followed by an additional 45 min of rest, simulating a full match for an unplaying substitute. During periods of rest, participants wore either standardised tracksuit bottoms (CON), or heated trousers (HEAT), over typical soccer attire. Results: Vastus lateralis temperature declined less in HEAT compared to CON following the 1st half in 2 °C (Δ − 4.39 ± 0.81 vs. − 6.21 ± 1.32 °C, P = 0.002) and 18 °C (Δ − 2.48 ± 0.71 vs. − 3.54 ± 0.88 °C, P = 0.003). These findings were also observed in the 2nd half for the 2 °C (Δ − 4.36 ± 1.03 vs. − 6.26 ± 1.04 °C, P = 0.002) and 18 °C (Δ − 2.85 ± 0.57 vs. − 4.06 ± 1 °C, P = 0.018) conditions. In addition, core temperature declined less in HEAT compared to CON following the 1st (Δ − 0.41 ± 0.25 vs. − 0.84 ± 0.41 °C, P = 0.037) and 2nd (Δ − 0.25 ± 0.33 vs. − 0.64 ± 0.34 °C, P = 0.028) halves of passive rest in 2 °C, with no differences in the 18 °C condition. Perceptual data confirmed that participants were more comfortable in HEAT vs. CON in 2 °C (P < 0.01). Conclusions: Following active warm-ups, heated trousers attenuate the decline in muscle temperature in ambient and cold environments. [ABSTRACT FROM AUTHOR]

This study aims to evaluate the energy-saving potential of passive solar heating systems in diverse global climates and introduce a new indicator, the passive solar heating indicator (PSHI), to enhance the efficiency of building designs. By collecting climate data from 600 cities worldwide through a simulation model, the present study employs polynomial regression to analyze the impact of outdoor temperature and solar radiation intensity on building energy savings. It also uses K-means cluster analysis to scientifically categorize cities based on their energy-saving potential. The findings underscore the benefits of both direct and indirect solar heating strategies in different climates. Significantly, the PSHI shows superior predictive accuracy and applicability over traditional indices, such as the irradiation temperature difference ratio (ITR) and the irradiation degree hour ratio (C-IDHR), especially when outdoor temperatures are close to indoor design temperatures. Moreover, the application of a cluster analysis provides hierarchical guidance on passive heating designs globally, paving the way for more accurate and customized energy-efficient building strategies. [ABSTRACT FROM AUTHOR]

The world is experiencing increased frequency, duration, and severity of life-threatening heat extremes. Most hospitalizations and excess deaths during extreme heat events are associated with preexisting diseases in older adults. As climate change persists, the global population ages and the number of individuals with chronic diseases expands, more people are at risk of adverse health outcomes during extreme heat events. Therefore, proactive preventive measures are urgently needed to mitigate heat-related health risks within these populations. In this context, passive heat therapy (e.g., hot baths, saunas, and water-perfused suits) emerges as a promising countermeasure to improve physiological resilience to a warming planet. Passive heating improves cardiovascular function and overall health in older adults and individuals living with chronic diseases, offering the prospect of reducing cardiovascular strain during hotter days. Moreover, some studies suggest that passive heat therapy can be an effective strategy for heat acclimation (i.e., improved thermoregulation). This review describes the existing literature on the effects of passive heat therapy on cardiovascular and thermoregulatory responses in individuals with higher heat-related health risks and explores the use of passive heating as a strategy for heat acclimation to mitigate health risks during extreme heat events. NEW & NOTEWORTHY: Passive heat therapy improves cardiovascular function and health in middle-aged and older adults living with or without chronic diseases. In addition, preliminary studies indicate that passive heat interventions can induce heat acclimation, improving thermoregulatory responses. Thus, passive heat therapy could serve as a preventive measure for people at risk of adverse health outcomes during extreme heat events, improving resilience to ongoing climate change. [ABSTRACT FROM AUTHOR]

Exercise and passive heating induce some similar vascular hemodynamic, circulating blood marker, and perceptual responses. However, it remains unknown whether post exercise hot water immersion can synergise exercise derived responses and if they differ from hot water immersion alone. This study investigated the acute responses to post moderate‐intensity exercise hot water immersion (EX+HWI) when compared to exercise (EX+REST) and hot water immersion (HWI+HWI) alone. Sixteen physically inactive middle‐aged adults (nine males and seven females) completed a randomized cross‐over counterbalanced design. Each condition consisted of two 30‐min bouts separated by 10 min of rest. Cycling was set at a power output equivalent to 50% V̇o2 peak. Water temperature was controlled at 40°C up to the mid sternum with arms not submerged. Venous blood samples and artery ultrasound scans were assessed at 0 (baseline), 30 (immediately post stressor one), 70 (immediately post stressor two), and 100 min (recovery). Additional physiological and perceptual measures were assessed at 10‐min intervals. Brachial and superficial femoral artery shear rates were higher after EX+HWI and HWI+HWI when compared with EX+REST (p < 0.001). Plasma nitrite was higher immediately following EX+HWI and HWI+HWI than EX+REST (p < 0.01). Serum interleukin‐6 was higher immediately after EX+HWI compared to EX+REST (p = 0.046). Serum cortisol was lower at 30 min in the HWI+HWI condition in contrast to EX+REST (p = 0.026). EX+HWI and HWI+HWI were more enjoyable than EX+REST (p < 0.05). Irrespective of whether hot water immersion proceeded exercise or heating, hot water immersion enhanced vascular and blood marker responses, while also being more enjoyable than exercise alone. [ABSTRACT FROM AUTHOR]

Hospitality institutions are significant consumers of water, electricity and gas resources. These resources may be scarce or critical in several locations. Authors have investigated strategies for efficient building operation, considering various energy carriers. Despite reported methods to enhance efficiency, nowadays they commonly have to be integrated into hotels from the design process through regular operation. This study aims to provide a detailed analysis of sustainable architecture in hotel design to decrease resource usage without compromising the quality of services provided. The considered design process is based on using a structured methodology focused on a energy management system that guarantees an efficient use of resources. The present study also considers incorporating renewable energy sources for the nominal operation of the hotel to achieve a net-zero energy building classification. The design of the building resulted in the proposed architecture that can maintain a comfortable temperature range of $17^{\circ } C$ to $24^{\circ } C$ in the guest rooms throughout the year. The energy generated from the proposed photovoltaic, thermal solar systems and rainwater harvesting can guarantee a nearly negligible net consumption of these resources for the hotel.

Whether glucose concentration increases during heat exposure because of reduced peripheral tissue uptake or enhanced appearance is currently unknown. This study aimed to report glucose concentrations in both capillary and venous blood in response to a glucose challenge during passive heating (PH) to assess whether heat exposure affects glucose uptake in healthy males. Twelve healthy male participants completed two experimental sessions, where they were asked to undertake an oral glucose tolerance test (OGTT) whilst immersed in thermoneutral (CON, 35.9 (0.6) °C) and hot water (HWI, 40.3 (0.5) °C) for 120 min. Venous and capillary blood [glucose], rectal temperature, and heart rate were recorded. [Glucose] area under the curve for HWI venous (907 (104) AU) differed from CON venous (719 (88) AU, all P < 0.001). No other differences were noted (P > 0.05). Compared with CON, HWI resulted in greater rectal temperature (37.1 (0.3) °C versus 38.6 (0.4) °C, respectively) and heart rate (69 (12) bpm versus 108 (11) bpm, respectively) on cessation (P < 0.001). An OGTT results in similar capillary [glucose] during hot and thermoneutral water immersion, whereas venous [glucose] was greater during HWI when compared with CON. This indicates that peripheral tissue glucose uptake is acutely reduced in response to HWI. Abbreviations: AUC: Area under the curve; CON: Thermoneutral immersion trial; HWI: Hot water immersion trial; OGTT: Oral glucose tolerance test; PH: Passive heating; $${\bar T_{{\rm{msk}}}}$$ T ˉ m s k : Mean skin temperature; Trec: Rectal temperature [ABSTRACT FROM AUTHOR]

Air-source heat pumps (ASHPs), as an active device, are widely used in building heating and cooling processes. However, in severe cold regions, they face reduced heating efficiency and frosting problems in winter. This paper proposes a new heating solution by coupling an ASHP with passive heating systems. It combines an ASHP with passive sunrooms and heat storage systems for heating. Through software simulations and mathematical modeling, the new scheme is compared and analyzed against traditional ASHP solutions to explore the performance of this scheme in rural houses in severe cold regions of China during winter. According to simulation and calculation analysis, on the coldest day of winter, the coupling scheme can provide approximately 99.41 kWh of heat to the indoors, which exceeds the 86.67 kWh required to maintain an indoor temperature of 20 °C. The system’s power consumption is 36.96 kWh, which is 66.88% lower than that of traditional heat pump heating. The study shows that the coupling system of an ASHP and passive heating has a good heating effect in severe cold regions. For the situation of insufficient solar energy at night, the design of phase-change materials and heat storage media can meet heating needs throughout the day.

This research aims to showcase the imperative of integrating passive cooling and heating techniques within buildings to effectively decrease energy consumption. To accomplish this objective, numerical simulations were conducted on a representative double-walled brick building in two cold desert climates using TRNSYS software. The simulations were performed to compare and evaluate the thermal and energy performance of two distinct passive techniques, one for cooling the reflective roof and the other for heating the Trombe wall (TW). The findings demonstrate that employing a reflective roof building with an air gap significantly reduces indoor temperatures by 3 °C during the hottest weekdays of summer, as compared to the reference building, across the two studied Moroccan climates. Moreover, this approach decreases the demand for cooling energy by an impressive 69–78 %. Similarly, the passive heating technique proves highly effective during winter, reducing energy requirements by 26–30 % while increasing indoor temperatures by over 2.9 °C. Combining both techniques proves to be the most efficient solution, resulting in a 37.87 % reduction in total annual energy consumption for cooling and heating in Er-Rachidia and a 30 % reduction in Ifran. These results strongly support the suggestion that Moroccan thermal regulations should incentivize the adoption of passive cooling and heating systems, particularly in cold desert climates.

Purpose: Rowers can be in marshaling areas for up to 20 to 25 min before the start of a race, which likely negates any benefits of an active warm-up, especially in cold environments. It is unknown if using a heated jacket following a standardized rowing warm-up can improve 2000-m rowing performance. Methods: On 2 separate occasions, 10 trained male rowers completed a standardized rowing warm-up, followed by 25 min of passive rest before a 2000-m rowing time trial on a rowing ergometer. Throughout the passive rest, the participants wore either a standardized tracksuit top (CON) or an externally heated jacket (HEAT). The trials, presented in a randomized crossover fashion, were performed in a controlled environment (temperature 8°C, humidity 50%). Rowing time-trial performance, core body temperature, and mean skin temperature, along with perceptual variables, were measured. Results: During the 25-min period, core body temperature increased in HEAT and decreased in CON (Δ0.54°C [0.74°C] vs −0.93°C [1.14°C]; P =.02). Additionally, mean skin temperature (30.22°C [1.03°C] vs 28.86°C [1.07°C]) was higher in HEAT versus CON (P <.01). In line with the physiological data, the perceptual data confirmed that participants were more comfortable in HEAT versus CON, and subsequently, rowing performance was improved in HEAT compared with CON (433.1 [12.7] s vs 437.9 [14.4] s, P <.01). Conclusion: The data demonstrate that an upper-body external heating garment worn following a warm-up can improve rowing performance in a cool environment. [ABSTRACT FROM AUTHOR]

The article focuses on a method of heating buildings by utilizing warm air circulation in closed channels located within external walls, referred to as “collector walls” by the author. These channels are also present in the roof and floors, creating a closed-loop system of interconnected air spaces that form a thermo-circulating heating structure. When the collector walls receive favourable solar exposure from the south, east, or west, the air circulating within the thermo-circulating heating structure is naturally heated through solar radiation, resulting in passive heating. However, in cases where solar radiation is insufficient, an external heat source is re-quired. Heating elements can be directly incorporated into the convection, such as in the lower part of the collector wall.

This study aims to evaluate the energy-saving potential of passive solar heating systems in diverse global climates and introduce a new indicator, the passive solar heating indicator (PSHI), to enhance the efficiency of building designs. By collecting climate data from 600 cities worldwide through a simulation model, the present study employs polynomial regression to analyze the impact of outdoor temperature and solar radiation intensity on building energy savings. It also uses K-means cluster analysis to scientifically categorize cities based on their energy-saving potential. The findings underscore the benefits of both direct and indirect solar heating strategies in different climates. Significantly, the PSHI shows superior predictive accuracy and applicability over traditional indices, such as the irradiation temperature difference ratio (ITR) and the irradiation degree hour ratio (C-IDHR), especially when outdoor temperatures are close to indoor design temperatures. Moreover, the application of a cluster analysis provides hierarchical guidance on passive heating designs globally, paving the way for more accurate and customized energy-efficient building strategies.

About 20% of all energy utilized worldwide is allocated to regulate the temperature of buildings through heating and cooling in response to seasonal changes. Numerous cutting-edge, low-carbon-footprint innovations have recently been demonstrated to assist resolve this issue, including passive radiative cooling and sun heating. Their accessibility is nevertheless constrained to particular seasons or climate zones by the steady and one-sided control of temperature. Here, taking advantage of recent breakthroughs in photonic manipulation and radiative heat transfer technology, we propose phase-transition metamaterials with dynamically passive and radiative thermal regulation capability for temperature control that can be scaled up for application in buildings. At a critical temperature, the sun absorptance of this metafilm can self-modulate from 0.9 to 0.18 as a result of temperature changes. This metafilm is made of reflective silver (Ag) thin film on top of polyethylene (PE) film with vanadium dioxide (VO 2) nanoparticles embedded in it. By varying the volume percentages of the VO 2 nanoparticles and the PE matrix thickness, this metafilm's optical performance can be tailored. We model the inactive dynamic thermal regulator's equilibrium temperature response to diurnal temperature swings. The industrial film extrusion approach has the potential to produce the nanoparticles embedded into the polymer structure, and the physical vapor deposition method can deposit the Ag thin film scalably, both of which are encouraging for scale-up deployment. This passive radiative heat thermal management technology can be potentially applied to regions with extreme annual temperature fluctuations. [Display omitted] • VO 2 -derived photonic metamaterials with switchable solar reflectance. • Transparent polyethylene film as a matrix provides a flexible feature. • Numerical simulation shows solar reflectance modulation from 0.9 to 0.18 from metallic to insulation. • Tunable solar reflectance by adjusting the geometric structures of the metafilm. [ABSTRACT FROM AUTHOR]

Purpose: Examine the effects of 42°C hot‐water immersion on muscle contraction function and motor unit discharge rates. Voluntary and evoked contraction assessments were examined first with a concomitant increase in the core and muscle temperature, and thereafter with increased muscle temperature but cooled core temperature. Methods: Fifteen participants (24.9 ± 5.6 years) performed neuromuscular assessments before, after, and ~15‐min after either 90‐min of 42°C (hot) or 36°C (control) water immersion. Maximal voluntary contraction (MVC) assessment of knee extension was performed along with surface electromyography (sEMG) (vastus lateralis and medialis [VL, VM]) and voluntary activation level (VAL). Resting evoked twitch was elicited for peak torque and time to peak torque analysis. In addition, the VL and VM motor unit discharge rates (MUDR) were measured. Results: After hot‐water immersion (core temperature ↑1°C; muscle temperature ↑2.4°C), MVC torque and VAL decreased (p < 0.05). The sEMG (VL and VM) and peak twitch torque did not change (p > 0.05), while time to peak torque decreased (p = 0.007). The VL and VM MUDR decreased, showing a time effect, after both water immersion conditions (36 and 42°C) (p > 0.001). Fifteen minutes after the hot‐water immersion (core temperature at baseline; muscle temperature ↑1.4°C), MVC torque returned to baseline, but VAL remained lower. The sEMG (VL and VM) remained unchanged. Peak twitch torque increased (p < 0.002) and time to peak torque remained lower (p = 0.028). The MUDR remained lower after both water immersion conditions (p < 0.05). Conclusion: Increased core temperature evoked by 42°C hot‐water immersion decreases MVC torque and VAL. However, a passive increase in muscle temperature improved evoked muscle contractile function (i.e., time to peak torque [after] and peak twitch torque [~15 min after]). Moreover, a passive increase in muscle temperature reduced the required MUDR to attain the same torque. [ABSTRACT FROM AUTHOR]

Purpose: Ultrasound-derived echo intensity (EI) has been used as a physiological marker for changes in skeletal muscle "quality" with physical training, disuse, aging, and neuromuscular disorders. However, the methodological and physiological factors influencing EI and its longitudinal change are still unclear. Here, we performed two separate experiments to investigate the effects of muscle temperature and fascicle angle, which are known to influence muscle tissue and sound wave properties and therefore affect EI. Methods: In experiment 1 (n = 16, 28.0 ± 6.6 yr), vastus lateralis (VL) ultrasonographic images were acquired and intramuscular temperature continuously recorded for 15 min after 20 min of heating to 40.4°C ± 0.7°C using a microwave device. In experiment 2 (n = 17, 30.2 ± 9.8 yr), VL sonographic images were obtained with the knee both fully extended (0°) and flexed to 90° and EI and fascicle angle measured post hoc. Fascicle movement was tracked during the passive knee flexion to ensure that sonographic images were obtained at the same muscle region. Knee flexion reduced muscle thickness, and we therefore reran analyses calculating EI using identical dimensions to minimize this effect. Results: EI decreased only immediately after the passive heating, and although a moderate, negative correlation was observed between EI and temperature (r rm = −0.36), the effect of muscle temperature was small (β = 0.97 (−1.89 to −0.06) per degree Celsius, P = 0.051). Nonetheless, EI increased as fascicle angle decreased, and a large, negative correlation (r rm = −0.85) was observed; the effect of fascicle angle on EI was large (β = 3.0 (−3.8 to −2.2) per degree, P < 0.01), and this was maintained when analyses were performed at a constant depth of the region of interest (β = 3.5 (−4.4 to −2.7) per degree, P < 0.01). Conclusions: These findings support the hypothesis that fascicle angle meaningfully affects VL EI but provides weak evidence of a temperature effect in vivo. Thus, acute fascicle angle alterations should be accounted for in studies using EI measurements, and longer-term studies should consider whether changes in EI might be partly explained by a change in fascicle angle. [ABSTRACT FROM AUTHOR]

The current global energy challenges require strategies to increase energy-independence across regions and individual countries in order to facilitate and foster the utilization of passive energy sources. As such, solar energy utilization for covering and offsetting building heating loads is a sustainable way to reduce energy consumption (electricity, gas etc.) for space heating. Trombe wall technology is a passive building solar heating system that can be modified and applied to mild and cold regions. This work presents a review of Trombe wall system's feasibility and applications across different climatic regions. Trombe wall systems are applicable as a secondary space heating source in mid-sunshine and cold regions. However, a number of design and structural aspects must be thoroughly considered, including the incorporation of PCMs, and the integration of PV/BIPV elements and other performance-improving aspects to enhance the system's thermal performance and output. The findings of this work can be used in potential future assessments of the Trombe wall system's technology in different climatic regions. [ABSTRACT FROM AUTHOR]

Abstract Trombe walls figure among many passive devices used in the Mediterranean climate to minimize heating demands in residential buildings. The thickness of this massive wall is a critical parameter that influences the effectiveness of the system. Insufficient wall thickness conducts to an important interior temperature fluctuation, and huge wall thickness will increase costs and thermal resistance. In this paper, the optimum thickness of four different construction materials (concrete, stone, adobe, and brick), which can be used in the Trombe wall, was determined using an energetic and economic analysis. The energetic results with TRNSYS software show that the best materials, which can contribute to a reduction by 50% in heating loads of a single room, are stone and concrete. For the economic analysis, the life cycle cost and the payback period were calculated for each construction material. The results show that the optimum thickness for stone and concrete are, respectively, 34 and 32 cm with a payback period of 2.85 and 2.65 years.

Abstract Background Prior to exercise, a warm-up routine has been suggested to be an imperative factor in task readiness with the anticipation that it will enhance performance. One of the key benefits of a warm-up is the increase in muscle and core temperature, which can be achieved in a variety of ways. An effective way to achieve improvements in core and muscle temperature is by performing an active warm-up. However, lengthy transition periods between an active warm-up and exercise performance are known to cause a decline in core and muscle temperature, thereby reducing performance capability. As such, methods are needed to assist athletes during transition periods, to maintain the benefits of a warm-up with the aim of optimising performance. Accordingly, the purpose of this review is to systematically analyse the evidence base that has investigated the use of passive heating to aide sporting performance when a transition period is experienced. Methods A systematic review and meta-analysis were undertaken following relevant studies being identified using PubMed, Web of Science, and EBSCO. Studies investigating the effects of passive heating strategies during the transition period between an active warm-up and exercise performance were included. The quality of the included studies were assessed by two independent reviewers using a modified version of the Physiotherapy Evidence Database scale. Results Seven studies, all high quality (mean = 7.6), reported sufficient data (quality score > 5) on the effects of passive heating strategies on exercise performance, these studies consisted of 85 well-trained athletes (78 male and 7 female). Passive heating strategies used between an active warm-up and exercise, significantly increased peak power output in all studies (ES = 0.54 [95% CI 0.17 to 0.91]). However, only a favourable trend was evident for exercise performance (ES = 1.07 [95% CI − 0.64 to 0.09]). Conclusions Based upon a limited number of well-conducted, randomised, controlled trials, it appears that passive heating strategies used between an active warm-up and exercise have a positive impact on peak power output. Although, additional research is necessary to determine the optimum procedure for passive warm-up strategies.

Abstract Background Many significant ecosystems, including important non-forest woody ecosystems such as the Cerrado (Brazilian savannah), are under threat from climate change, yet our understanding of how increasing temperatures will impact native vegetation remains limited. Temperature manipulation experiments are important tools for investigating such impacts, but are often constrained by access to power supply and limited to low-stature species, juvenile individuals, or heating of target organs, perhaps not fully revealing how entire or mature individuals and ecosystems will react to higher temperatures. Results We present a novel, modified open top chamber design for in situ passive heating of whole individuals up to 2.5 m tall (but easily expandable) in remote field environments with strong solar irradiance. We built multiple whole-tree heating structures (WTHSs) in an area of Cerrado around native woody species Davilla elliptica and Erythroxylum suberosum to test the design and its effects on air temperature and humidity, while also studying the physiological responses of E. suberosum to short-term heating. The WTHSs raised internal air temperature by approximately 2.5 °C above ambient during the daytime. This increased to 3.4 °C between 09:00 and 17:00 local time when thermal impact was greatest, and during which time mean internal temperatures corresponded closely with maximum ambient temperatures. Heating was consistent over time and across WTHSs of variable size and shape, and they had minimal effect on humidity. E. suberosum showed no detectable response of photosynthesis or respiration to short-term experimental heating, but some indication of acclimation to natural temperature changes. Conclusions Our WTHSs produced a consistent and reproducible level of daytime heating in line with mid-range climate predictions for the Cerrado biome by the end of the century. The whole-tree in situ passive heating design is flexible, low-cost, simple to build using commonly available materials, and minimises negative impacts associated with passive chambers. It could be employed to investigate the high temperature responses of many understudied species in a range of complex non-forest environments with sufficient solar irradiance, providing new and important insights into the possible impacts of our changing climate.

Passive hyperthermia induces a range of physiological responses including augmenting skeletal muscle mRNA expression. This experiment aimed to examine gene and protein responses to prolonged passive leg hyperthermia. Seven young participants underwent 3 h of resting unilateral leg heating (HEAT) followed by a further 3 h of rest, with the contralateral leg serving as an unheated control (CONT). Muscle biopsies were taken at baseline (0 h), and at 1.5, 3, 4, and 6 h in HEAT and 0 and 6 h in CONT to assess changes in selected mRNA expression via qRT-PCR, and HSP72 and VEGFα concentration via ELISA. Muscle temperature (Tm) increased in HEAT plateauing from 1.5 to 3 h (+ 3.5±1.5°C from 34.2±1.2°C baseline value; P < 0.001), returning to baseline at 6 h. No change occurred in CONT. Endothelial nitric oxide synthase (eNOS), Forkhead box O1 (FOXO-1), Hsp72, and VEGFα mRNA increased in HEAT (P < 0.05); however, post hoc analysis identified that only Hsp72 mRNA statistically increased (at 4 h vs. baseline). When peak change during HEAT was calculated angiopoietin 2 (ANGPT-2) decreased (-0.4 ± 0.2-fold), and C-C motif chemokine ligand 2 (CCL2) (+ 2.9±1.6-fold), FOXO-1 (+ 6.2±4.4-fold), Hsp27 (+ 2.9 ± 1.7-fold), Hsp72 (+ 8.5±3.5-fold), Hsp90a (+ 4.6±3.7-fold), and VEGFα (+ 5.9 ±3.1-fold) increased from baseline (all P < 0.05). At 6 h Tm were not different between limbs (P = 0.582; CONT = 32.5±1.6°C, HEAT = 34.3±1.2°C), and only ANGPT-2 (P = 0.031; -1.3±1.4-fold) and VEGFα (P = 0.030; 1.1 ±1.2-fold) differed between HEAT and CONT. No change in VEGFα or HSP72 protein concentration were observed over time; however, peak change in VEGFα did increase (P < 0.05) in HEAT (+140±184 pg·mL-1) versus CONT (+ 7±86 pg·mL-1). Passive hyperthermia transiently augmented ANGPT-2, CCL2, eNOS, FOXO-1, Hsp27, Hsp72, Hsp90a and VEGFα mRNA, and VEGFα protein. [ABSTRACT FROM AUTHOR]

Increasing energy demand around the world and meeting this demand from fossil fuels cause negative consequences such as global warming. For reducing the impact of these results, the use of renewable resources is gaining importance. Heating of buildings is a high energy dependent process, thus benefiting from solar energy is advantageous for locations with a long hours of sunshine. Manisa is also advantageous in terms of sunshine duration. One of the solar heating applications is the Trombe wall. In this study, a classical Trombe wall (Type-1) and a different type of Trombe wall (Type-2) were designed and these two types of walls were compared in terms of energy, economic and environmental aspects. During analyzes, the air channel depth and the variation of solar radiation intensity, which are important parameters for Trombe walls, are discussed. As a result of the calculations, the energy efficiency for Type-1 and Type-2 walls was found to be 0,37 and 0,46, respectively, at the optimized operating parameters for January (for 500 W/m2 solar radiation intensity and 0,35 m air duct depth). Again with these parameters, it has been calculated that the indoor temperature rises to the maximum values of 19,6 oC and 21,8 oC for Type-1 and Type-2 walls at 15.00. Economic analysis indicated that payback period of the Type-1 and Type-2 walls are 7,3 and 6,9 years, respectively. It has been calculated that the use of Type-1 and Type-2 walls provides a reduction of 5985,5 kg and 6405 kg in total carbon emissions, respectively. [ABSTRACT FROM AUTHOR]

Declines in muscle force, power, and contractile function can be observed in older adults, clinical populations, inactive individuals, and injured athletes. Passive heating exposure (e.g., hot baths, sauna, or heated garments) has been used for health purposes, including skeletal muscle treatment. An acute increase in muscle temperature by passive heating can increase the voluntary rate of force development and electrically evoked contraction properties (i.e., time to peak twitch torque, half-relation time, and electromechanical delay). The improvements in the rate of force development and evoked contraction assessments with increased muscle temperature after passive heating reveal peripheral mechanisms' potential role in enhancing muscle contraction. This review aimed to summarise, discuss, and highlight the potential role of an acute passive heating stimulus on skeletal muscle cells to improve contractile function. These mechanisms include increased calcium kinetics (release/reuptake), calcium sensitivity, and increased intramuscular fluid. [ABSTRACT FROM AUTHOR]

Trombe walls provide a passive source of heating and ventilation for buildings. However, Trombe walls can also cause overheating during hot and sunny weather conditions. In this work, we investigate the potential of a multifunctional Trombe wall design, comprising a tinted acrylic sheet submerged in a water wall that functions as a thermal storage medium. The tinted acrylic sheet absorbs incident light, which is then converted to heat and absorbed by the water. The proposed Trombe wall can function as a tinted semi-transparent window to add aesthetic value. Furthermore, heated water rises to the top of the Trombe wall where it can be removed, which provides the dual benefit of preventing overheating and providing a source of preheated water for applications within the building. Experimental results performed on a laboratory-scale Trombe wall prototype showed that the percentage of solar-simulated light energy incident onto the Trombe wall prototype, over a period of five hours, that was stored as thermal energy in the water increased from 60.3% to 83.2% when tinted glass was inserted in the water storage wall. Furthermore, the temperature of the water at the top of the Trombe wall reached ~56 °C, which is suitable to be used as pre-heated water in building applications. [ABSTRACT FROM AUTHOR]

This investigation assessed the psycho-physiological and performance effects of hot water immersion (HWI) implemented either before or after a repeated-sprint training in hypoxia (RSH) session conducted in the heat. Ten participants completed three RSH trials (3 × 10 × 5-s sprints), conducted at 40°C and simulated altitude of 3000 m. A 30-min monitoring period preceded and followed all exercise sessions. In PRE, the pre-exercise period was HWI, and the post-exercise period was seated rest in temperate conditions. This combination was reversed in POST. In CON, participants were seated in temperate conditions for both periods. Compared to CON, PRE elicited a reduction in power output during each repeated-sprint set (14.8–16.2%, all p < 0.001), and a significantly higher core temperature (Tc) during the pre-exercise period and throughout the exercise session (p < 0.001 and p = 0.025, respectively). In POST, power output and Tc until the end of exercise were similar to CON, with Tc higher at the conclusion of the post-exercise period (p < 0.001). Time across the entire protocol spent ≥38.5°C Tc was significantly longer in PRE (48.1 ± 22.5 min) than POST (31.0 ± 11.3 min, p = 0.05) and CON (15.8 ± 16.3 min, p < 0.001). Employing HWI following RSH conducted in the heat provides effective outcomes regarding physiological strain and cycling performance when compared to pre-exercise or no HWI. [ABSTRACT FROM AUTHOR]

Heat exposure's effect on glucose tolerance depends on the amount of body exposed, likely relating to autonomic nervous system balance. We assessed how partial-body heat exposure at two different levels of the lower extremities affects glucose tolerance and autonomic nervous system balance, measured via heart rate variability. We hypothesized feet-heating would improve glucose tolerance without affecting heart rate variability, while calf-heating would worsen glucose tolerance and decrease heart rate variability compared to a thermoneutral control condition. In a randomized, controlled, crossover trial, healthy participants' ( N  = 31, 23(3) years, 45% male) glucose tolerance was measured in (A) thermoneutral; (B) feet-heating; and (C) calf-heating conditions. Every 30 min for 2 h, blood glucose, heart rate, heart rate variability, tympanic temperature, thermal comfort scores, and blood pressure were measured. There were significant interactions between condition and time for blood glucose ( F (4.6,72.6) = 2.6, p  = 0.036), heart rate ( F (3.4, 54.5) = 3.5, p  = 0.017), heart rate variability ( F (4.3,63.2) = 7.5, p  < .0001), tympanic temperature ( F (8, 268) = 2.4, p  = 0.014), and thermal comfort scores ( F (8, 248) = 22.1, p  < 0.0001). Calf-heating increased 90 min glucose (+12 (95% confidence interval, CI: 3-21) mg/dL, p  = 0.013) and decreased heart rate variability throughout (mean decrease: 13%-22%, p  < 0.007), while feet-heating lowered 90 min glucose (-7 (95% CI: -16 to +1) mg/dL, p  = 0.090) without affecting heart rate variability ( p  = 0.14-0.99). Blood pressure and body temperature were similar between conditions, but heart rate and thermal comfort scores increased with heating. Calf-heating worsens, while feet-heating may improve, glucose tolerance. Changes in heart rate variability coincided with changes in glucose tolerance despite unchanged body temperature. Whether heart rate variability can be used to monitor autonomic nervous system balance during heating to optimize its acute effect on glycemic indices should be further explored., Competing Interests: The authors have no conflicts of interest to declare.

Background: Prior to exercise, a warm-up routine has been suggested to be an imperative factor in task readiness with the anticipation that it will enhance performance. One of the key benefits of a warm-up is the increase in muscle and core temperature, which can be achieved in a variety of ways. An effective way to achieve improvements in core and muscle temperature is by performing an active warm-up. However, lengthy transition periods between an active warm-up and exercise performance are known to cause a decline in core and muscle temperature, thereby reducing performance capability. As such, methods are needed to assist athletes during transition periods, to maintain the benefits of a warm-up with the aim of optimising performance. Accordingly, the purpose of this review is to systematically analyse the evidence base that has investigated the use of passive heating to aide sporting performance when a transition period is experienced. Methods: A systematic review and meta-analysis were undertaken following relevant studies being identified using PubMed, Web of Science, and EBSCO. Studies investigating the effects of passive heating strategies during the transition period between an active warm-up and exercise performance were included. The quality of the included studies were assessed by two independent reviewers using a modified version of the Physiotherapy Evidence Database scale. Results: Seven studies, all high quality (mean = 7.6), reported sufficient data (quality score > 5) on the effects of passive heating strategies on exercise performance, these studies consisted of 85 well-trained athletes (78 male and 7 female). Passive heating strategies used between an active warm-up and exercise, significantly increased peak power output in all studies (ES = 0.54 [95% CI 0.17 to 0.91]). However, only a favourable trend was evident for exercise performance (ES = 1.07 [95% CI − 0.64 to 0.09]). Conclusions: Based upon a limited number of well-conducted, randomised, controlled trials, it appears that passive heating strategies used between an active warm-up and exercise have a positive impact on peak power output. Although, additional research is necessary to determine the optimum procedure for passive warm-up strategies. [ABSTRACT FROM AUTHOR]

Trombe walls figure among many passive devices used in the Mediterranean climate to minimize heating demands in residential buildings. The thickness of this massive wall is a critical parameter that influences the effectiveness of the system. Insufficient wall thickness conducts to an important interior temperature fluctuation, and huge wall thickness will increase costs and thermal resistance. In this paper, the optimum thickness of four different construction materials (concrete, stone, adobe, and brick), which can be used in the Trombe wall, was determined using an energetic and economic analysis. The energetic results with TRNSYS software show that the best materials, which can contribute to a reduction by 50% in heating loads of a single room, are stone and concrete. For the economic analysis, the life cycle cost and the payback period were calculated for each construction material. The results show that the optimum thickness for stone and concrete are, respectively, 34 and 32 cm with a payback period of 2.85 and 2.65 years. [ABSTRACT FROM AUTHOR]

Passive hot water immersion (PHWI) provides a peripheral vasculature shear stimulus comparable to low-intensity exercise within the active skeletal muscle, whereas moderate- and high-intensity exercise elicit substantially greater shear rates in the peripheral vasculature, likely conferring greater vascular benefits. Notably, few studies have compared postintervention shear rates in the peripheral and cerebral vasculature after high-intensity exercise and PHWI, especially considering that the postintervention recovery period represents a key window in which adaptation occurs. Therefore, we aimed to compare shear rates in the internal carotid artery (ICA), vertebral artery (VA), and common femoral artery (CFA) between high-intensity exercise and whole body PHWI for up to 80 min after intervention. Fifteen healthy (27 ± 4 yr), moderately trained individuals underwent three time-matched interventions in a randomized order that included 30 min of whole body immersion in a 42°C hot bath, 30 min of treadmill running and 5 × 4-min high-intensity intervals (HIIE). There were no differences in ICA (P = 0.4643) and VA (P = 0.1940) shear rates between PHWI and exercise (both continuous and HIIE) after intervention. All three interventions elicited comparable increases in CFA shear rate after intervention (P = 0.0671); however, CFA shear rate was slightly higher 40 min after threshold running (P = 0.0464) and slightly higher, although not statistically, for HIIE (P = 0.0565) compared with PHWI. Our results suggest that timeand core temperature-matched high-intensity exercise and PHWI elicit limited changes in cerebral shear and comparable increases in peripheral vasculature shear rates when measured for up to 80 min after intervention. [ABSTRACT FROM AUTHOR]

Impaired endothelial insulin signaling and consequent blunting of insulin-induced vasodilation is a feature of type 2 diabetes (T2D) that contributes to vascular disease and glycemic dysregulation. However, the molecular mechanisms underlying endothelial insulin resistance remain poorly known. Herein, we tested the hypothesis that endothelial insulin resistance in T2D is attributed to reduced expression of heat shock protein 72 (HSP72). HSP72 is a cytoprotective chaperone protein that can be upregulated with heating and is reported to promote insulin sensitivity in metabolically active tissues, in part via inhibition of JNK activity. Accordingly, we further hypothesized that, in individuals with T2D, 7 days of passive heat treatment via hot water immersion to waist level would improve leg blood flow responses to an oral glucose load (i.e., endogenous insulin stimulation) via induction of endothelial HSP72. In contrast, we found that: 1) endothelial insulin resistance in T2D mice and humans was not associated with reduced HSP72 in aortas and venous endothelial cells, respectively; 2) after passive heat treatment, improved leg blood flow responses to an oral glucose load did not parallel with increased endothelial HSP72; and 3) downregulation of HSP72 (via small-interfering RNA) or upregulation of HSP72 (via heating) in cultured endothelial cells did not impair or enhance insulin signaling, respectively, nor was JNK activity altered. Collectively, these findings do not support the hypothesis that reduced HSP72 is a key driver of endothelial insulin resistance in T2D but provide novel evidence that lower-body heating may be an effective strategy for improving leg blood flow responses to glucose ingestion-induced hyperinsulinemia. [ABSTRACT FROM AUTHOR]

Background: Many significant ecosystems, including important non-forest woody ecosystems such as the Cerrado (Brazilian savannah), are under threat from climate change, yet our understanding of how increasing temperatures will impact native vegetation remains limited. Temperature manipulation experiments are important tools for investigating such impacts, but are often constrained by access to power supply and limited to low-stature species, juvenile individuals, or heating of target organs, perhaps not fully revealing how entire or mature individuals and ecosystems will react to higher temperatures. Results: We present a novel, modified open top chamber design for in situ passive heating of whole individuals up to 2.5 m tall (but easily expandable) in remote field environments with strong solar irradiance. We built multiple whole-tree heating structures (WTHSs) in an area of Cerrado around native woody species Davilla elliptica and Erythroxylum suberosum to test the design and its effects on air temperature and humidity, while also studying the physiological responses of E. suberosum to short-term heating. The WTHSs raised internal air temperature by approximately 2.5 °C above ambient during the daytime. This increased to 3.4 °C between 09:00 and 17:00 local time when thermal impact was greatest, and during which time mean internal temperatures corresponded closely with maximum ambient temperatures. Heating was consistent over time and across WTHSs of variable size and shape, and they had minimal effect on humidity. E. suberosum showed no detectable response of photosynthesis or respiration to short-term experimental heating, but some indication of acclimation to natural temperature changes. Conclusions: Our WTHSs produced a consistent and reproducible level of daytime heating in line with mid-range climate predictions for the Cerrado biome by the end of the century. The whole-tree in situ passive heating design is flexible, low-cost, simple to build using commonly available materials, and minimises negative impacts associated with passive chambers. It could be employed to investigate the high temperature responses of many understudied species in a range of complex non-forest environments with sufficient solar irradiance, providing new and important insights into the possible impacts of our changing climate. [ABSTRACT FROM AUTHOR]

Heating and ventilation in the building is essential to establish thermal comfort. The modern means invented to provide us with our heating and ventilation needs are generally expensive and represent sources of pollution. It is for this reason that there are several studies directed towards the research of renewable energies and non-polluting economic systems. The simulation of such a natural system at an almost low cost is the subject of our study in this work. In this work, a numerical study of passive heating and ventilation was made by natural convection in a room containing a heated vertical wall. In the case of heating, the system is closed and two openings are considered in the heated vertical wall allowing the re-circulation of the air in the room and therefore the heating of this latter. In the case of ventilation, the room is open to the outside through two inlet and outlet openings allowing the air circulation from the outside into the room and from the room into the outside which leads to ventilate the room. Numerical results with different mesh and Rayleigh number have been presented and their effects have been discussed.

• The solar drying process is an eco-friendly method for preserving agricultural produce, with a focus on drying Mango pulp. • Organic paraffin wax as a Phase Change Material (PCM) in a portable solar dryer as the heat storing material. • During peak sunshine hours, the excess heat can be stored and used in the off-sunshine hours. • When compared to the sun-dried products, the solar-dried products had better colour, aroma, and quality. Food drying is an important phase in the safeguarding of agricultural by products that assist as raw materials for a variety of end applications. In the Thermal Energy Storage (TES) application a Phase Change Material (PCM) is the suitable material. In this research, paraffin wax was utilized in the planning and building of the solar dryer. The novelty of this work is to reduce the drying duration and increases the drying efficiency. Ripened mango was grinded and dried using different method to preserve and improve the shelf life of that dried product. To create nutritious dried mango cubes for snacking. When compared to conventional drying methods, solar drying with PCM for drying mango pulp has shown good quality retention. The outcome revealed that PCM integrated in the solar dryer has the lowest drying duration compared with open sun dry and without PCM. In terms of quality, color, and scent, solar-dried items outperform sun-dried ones. [ABSTRACT FROM AUTHOR]

In this study, a passive solar house prototype was built using Trombe wall and was tested in the semi-arid region of Batna, in eastern Algeria. Traditional local materials (stone and adobe) were used for the construction of the thermal storage wall. A new local bio-based material made from date palm trunks was used for the insulation of the passive house prototype. For a better understanding of passive house heating and for a comparative study, a numerical simulation, using Fluent, was carried out. The aim of this study was to supply recommendations for improving the passive systems and to participate to the energy consumption control in the building sector. The results show that the experimental and numerical simulation results are in good agreement. The optimal orientation of the solar passive house has been determined, which is at 160° southeast. The use of local and bio-based materials has proven its effectiveness in the construction of the passive house. The thermal behavior of date palm wood has been found to be close to those of insulation materials commonly used in buildings. That means it has the same thermal insulation ability (thermal conductivity). On the other hand, the results show that the thermal efficiency of the passive solar heating system, with an adobe wall is significantly higher (50%) than that with a stone wall (30.7%). [ABSTRACT FROM AUTHOR]

Aerobic exercise induces mast cell degranulation and increases histamine formation by histidine decarboxylase, resulting in an ~150% increase in intramuscular histamine. The purpose of this study was to determine if the increase in skeletal muscle temperature associated with exercise is sufficient to explain this histamine response. Specifically, we hypothesized that local passive heating that mimics the magnitude and time course of changes in skeletal muscle temperature observed during exercise would result in increased intramuscular histamine concentrations comparable to exercising values. Seven subjects participated in the main study in which pulsed short-wave diathermy was used to passively raise the temperature of the vastus lateralis over 60 min. Heating increased intramuscular temperature from 32.6°C [95% confidence interval (CI) 32.0°C to 33.2°C] to 38.9°C (38.7°C to 39.2°C) (P < 0.05) and increased intramuscular histamine concentration from 2.14 ng/mL (1.92 to 2.36 ng/mL) to 2.97 ng/mL (2.57 to 3.36 ng/mL) (P < 0.05), an increase of 41%. In a follow-up in vitro experiment using human-derived cultured mast cells, heating to comparable temperatures did not activate mast cell degranulation. Therefore, it appears that exercise-associated changes in skeletal muscle temperature are sufficient to generate elevations in intramuscular histamine concentration. However, this thermal effect is most likely due to changes in de novo histamine formation via histidine decarboxylase and not due to degranulation of mast cells. In conclusion, physiologically relevant increases in skeletal muscle temperature explain part, but not all, of the histamine response to aerobic exercise. This thermal effect may be important in generating positive adaptations to exercise training. [ABSTRACT FROM AUTHOR]

A dual-channel solar thermal storage wall system with eutectic phase change material is studied. The full-day cooling load in summer and heating load in winter can be both decreased by this novel system. To investigate the airflow in the dual channel, mixed area assumptions based on the experimental results are summarized. Dynamic mathematical models of the system under four work modes are established and verified by the experimental results. The average RMSD (root mean square deviation) value is 0.35% in summer and 0.95% in winter. By analyzing the heat flux, the combination of dual channel and PCM is proven to decrease and delay cooling load both in the daytime and nighttime of summer. In winter's daytime, the thermal efficiency is promoted by the dual channel. And in winter's nighttime, the system is able to heat the room constantly by the PCM boards. Based on parameter researches, the optimum phase change temperature range and the optimum thickness of the PCM are 26–30 °C, 1.5 cm in summer and 16–22 °C, 0.6 cm in winter respectively. To reach the optimum annual thermal performance, the coverage area is 2 m2 for this system. [ABSTRACT FROM AUTHOR]

This work aims at answering the question–to what extent thermally compliant buildings are involved in ensuring the winter indoor thermal comfort of occupants in cold semi-arid climates in Morocco. Real-time monitoring of a new-built university building located in eastern Morocco was conducted. The good agreement between the measured and simulated temperatures of the case study building confirmed the accuracy of the developed model. Thereafter, the thermal performance of different external wall configurations was investigated. The results show that compliant buildings guarantee better comfort conditions in winter by passively increasing the indoor air temperature by up to 2 °C, resulting in a maximum percentage of dissatisfaction of less than 13%. The winter discomfort hours based on a temperature set point of 16 °C are reduced by 95% compared to typical buildings. Moreover, the thermal compliance of buildings significantly reduces the daily air temperature amplitude, leading to a periodic dynamic behaviour without peak loads, which could be effective for the building energy management. The efficacy of earthen walls in regulating indoor temperatures was also confirmed due to the excellent thermal inertia of earth. For optimum winter comfort (20 °C), the implementation of the Moroccan building energy code shows up to 72% of reduction in heating demand when applied to conventional buildings.