Search

The impact of housing temperature on exercise‐induced metabolic adaptations is not well understood, despite extensive research on the benefits of exercise for metabolic health. The aim of this study was to elucidate how housing temperatures influence the molecular responses and metabolic benefits of exercise in mice. Male C57BL/6N mice were housed at either room temperature (RT, 21°C) or in a thermoneutral environment (TN, 29°C) and subjected to either a 6‐week or acute exercise regimen. The results demonstrated that chronic exercise in TN conditions significantly improved glucose tolerance, whereas no such improvement was observed in RT conditions. Exercise reduced adipocyte size in inguinal and epididymal white adipose tissue in RT conditions, but no significant exercise‐induced browning of inguinal white adipose tissue was detected at either housing temperature. Additionally, housing temperature predominantly influenced key metabolic proteins in skeletal muscle, with exercise and temperature exhibiting interactive effects on glycogen synthase, Glut4 and Pgc‐1α. Moreover, the regulation of exerkines, including Fgf21, fetuin‐A, irisin, Gdf15, spexin and apelin, was temperature dependent after both long‐term and acute exercise. Notably, expression of Metrnl was consistently upregulated in skeletal muscle after long‐term exercise in both RT and TN environments, but was downregulated after acute exercise. These findings highlight that environmental temperature critically modulates the metabolic benefits of exercise and the expression of exerkines. The results of this study suggest that conventional RT conditions might obscure the full metabolic effects of exercise. We recommend the use of TN conditions in future research to reduce confounding factors and provide a more accurate assessment of the metabolic benefits of exercise. [ABSTRACT FROM AUTHOR]

Background: Sub-thermoneutral housing increases facultative thermogenesis in mice, which may mask the pre-clinical efficacy of anti-obesity strategies that target energy expenditure (EE). Here, we quantified the impact of protonophore treatment on whole-body energetics in mice housed at 30°C. Methods: C57BL/6J mice (n = 48, 24M/24F) were housed at 24°C for 2 weeks; 32 (16M/16F) were then transitioned to 30°C for a further 4 weeks. Following 2 weeks acclimation at 30°C, mice (n = 16 per group, 8M/8F) received either normal (0 mg/L; Control) or supplemented (400 mg/L; 2,4-Dinitrophenol [DNP]) drinking water. Mice were singly housed in metabolic cages to determine total EE (TEE) and its components via respiratory gas exchange. Mitochondrial respiratory function of permeabilized liver tissue was determined by high-resolution respirometry. Results: Transitioning mice from 24°C to 30°C reduced TEE and basal EE (BEE) by 16% and 41%, respectively (both P < 0.001). Compared to 30°C controls, TEE was 2.6 kcal/day greater in DNP-treated mice (95% CI: 1.6–3.6 kcal/day, P < 0.001), which was partly due to a 1.2 kcal/day higher BEE in DNP-treated mice (95% CI: 0.6–1.7 kcal/day, P < 0.001). The absolute TEE of 30°C DNP-treated mice was lower than that of mice housed at 24°C in the absence of DNP (DNP: 9.4 ± 0.7 kcal/day vs. 24°C control: 10.4 ± 1.5 kcal/day). DNP treatment reduced overall body fat of females by 2.9 percentage points versus sex-matched controls (95% CI: 1.3%–4.5%, P < 0.001), which was at least partly due to a reduction in inguinal white fat mass. Conclusion: Protonophore treatment markedly increases EE in mice housed at 30°C. The magnitude of change in TEE of mice receiving protonophore treatment at 30°C was smaller than that brought about by transitioning mice from 24°C to 30°C, emphasizing that housing temperature must be considered when assessing anti-obesity strategies that target EE in mice. [ABSTRACT FROM AUTHOR]

Caloric restriction (CR) results in reduced energy and protein intake, raising questions about protein restriction's contribution to CR longevity benefits. We kept ad libitum (AL)–fed male C57BL/6J mice at 27°C (AL27) and pair-fed (PF) mice at 22°C (22(PF27)). The 22(PF27) group was fed to match AL27 while restricted for calories due to cold-induced metabolism. The 22(PF27) mice had significantly lower body weight, lean mass, fat mass, leptin, IGF-1, and TNF-α levels than AL27 mice (p<0.001 for all). Manipulations over ~11 weeks resulted in significant differences in body temperature, physical activity, and expression of key genes linked to hunger in the hypothalamus. Survival was significantly greater in 22(PF27) compared to AL27 overall (p<0.001). CR in the context of equivalent energy and protein intake resulted in hormonal, metabolic, and physiological benefits and extended longevity. Hence, energy imbalance, rather than low energy or protein intake per se, mediates the benefits of CR. [ABSTRACT FROM AUTHOR]

BackgroundSub-thermoneutral housing increases facultative thermogenesis in mice, which may mask the pre-clinical efficacy of anti-obesity strategies that target energy expenditure (EE). Here, we quantified the impact of protonophore treatment on whole-body energetics in mice housed at 30°C.MethodsC57BL/6J mice (n = 48, 24M/24F) were housed at 24°C for 2 weeks; 32 (16M/16F) were then transitioned to 30°C for a further 4 weeks. Following 2 weeks acclimation at 30°C, mice (n = 16 per group, 8M/8F) received either normal (0 mg/L; Control) or supplemented (400 mg/L; 2,4-Dinitrophenol [DNP]) drinking water. Mice were singly housed in metabolic cages to determine total EE (TEE) and its components via respiratory gas exchange. Mitochondrial respiratory function of permeabilized liver tissue was determined by high-resolution respirometry.ResultsTransitioning mice from 24°C to 30°C reduced TEE and basal EE (BEE) by 16% and 41%, respectively (both P < 0.001). Compared to 30°C controls, TEE was 2.6 kcal/day greater in DNP-treated mice (95% CI: 1.6–3.6 kcal/day, P < 0.001), which was partly due to a 1.2 kcal/day higher BEE in DNP-treated mice (95% CI: 0.6–1.7 kcal/day, P < 0.001). The absolute TEE of 30°C DNP-treated mice was lower than that of mice housed at 24°C in the absence of DNP (DNP: 9.4 ± 0.7 kcal/day vs. 24°C control: 10.4 ± 1.5 kcal/day). DNP treatment reduced overall body fat of females by 2.9 percentage points versus sex-matched controls (95% CI: 1.3%–4.5%, P < 0.001), which was at least partly due to a reduction in inguinal white fat mass.ConclusionProtonophore treatment markedly increases EE in mice housed at 30°C. The magnitude of change in TEE of mice receiving protonophore treatment at 30°C was smaller than that brought about by transitioning mice from 24°C to 30°C, emphasizing that housing temperature must be considered when assessing anti-obesity strategies that target EE in mice.

Lipoprotein lipase (LPL) is secreted into the interstitial spaces by parenchymal cells and then transported into capillaries by GPIHBP1. LPL carries out the lipolytic processing of triglyceride (TG)-rich lipoproteins (TRLs), but the tissue-specific regulation of LPL is incompletely understood. Plasma levels of TG hydrolase activity after heparin injection are often used to draw inferences about intravascular LPL levels, but the validity of these inferences is unclear. Moreover, plasma TG hydrolase activity levels are not helpful for understanding LPL regulation in specific tissues. Here, we sought to elucidate LPL regulation under thermoneutral conditions (30 °C). To pursue this objective, we developed an antibody-based method to quantify (in a direct fashion) LPL levels inside capillaries. At 30 °C, intracapillary LPL levels fell sharply in brown adipose tissue (BAT) but not heart. The reduced intracapillary LPL levels were accompanied by reduced margination of TRLs along capillaries. ANGPTL4 expression in BAT increased fourfold at 30 °C, suggesting a potential explanation for the lower intracapillary LPL levels. Consistent with that idea, Angptl4 deficiency normalized both LPL levels and TRL margination in BAT at 30 °C. In Gpihbp1-/- mice housed at 30 °C, we observed an ANGPTL4-dependent decrease in LPL levels within the interstitial spaces of BAT, providing in vivo proof that ANGPTL4 regulates LPL levels before LPL transport into capillaries. In conclusion, our studies have illuminated intracapillary LPL regulation under thermoneutral conditions. Our approaches will be useful for defining the impact of genetic variation and metabolic disease on intracapillary LPL levels and TRL processing.

The objective was to assess whether low-protein (LP) diets regulate food intake (FI) and thermogenesis differently during thermoneutral (TN) and heat stress (HS) conditions. Two-hundred-day-old male broiler chicks were weight-matched and assigned to 36 pens with 5–6 chicks/pen. After 2 weeks of acclimation, birds were subjected into four groups (9 pens/group) including (1) a normal-protein diet under TN (ambient temperature), (2) an LP diet under TN, (3) a normal-protein diet under HS (35 °C for 7 h/day), and (4) an LP diet under HS, for 4 weeks. During HS, but not TN, LP tended to decrease FI, which might be associated with a lower mRNA abundance of duodenal ghrelin and higher GIP during HS. The LP group had a higher thermal radiation than NP under TN, but during HS, the LP group had a lower thermal radiation than NP. This was linked with higher a transcript of muscle β1AR and AMPKα1 during TN, but not HS. Further, LP increased the gene expression of COX IV during TN but reduced COX IV and the sirtuin 1 abundance during HS. The dietary protein content differentially impacted plasma metabolome during TN and HS with divergent changes in amino acids such as tyrosine and tryptophan. Compared to NP, LP had increased abundances of p_Tenericutes, c_Mollicutes, c_Mollicutes_RF9, and f_tachnospiraceae under HS. Overall, LP diets may mitigate the negative outcome of heat stress on the survivability of birds by reducing FI and heat production. The differential effect of an LP diet on energy balance during TN and HS is likely regulated by gut and skeletal muscle and alterations in plasma metabolites and cecal microbiota. [ABSTRACT FROM AUTHOR]

Recently, there has been growing interest in utilizing ammonia through its decomposition process for on-site hydrogen production, primarily due to technical problems in hydrogen generation and storage. As ammonia decomposition is an endothermic reaction, an external heat source is required to facilitate the reaction. To address this, an ammonia autothermal reforming process that directly integrates ammonia decomposition and oxidation using air as the source of oxygen within a single reactor vessel was proposed. This process eliminates the need for additional external heat sources and simplifies the process. The design of the reactor incorporates an air distribution structure that allows for achieving a specified temperature range for the desired reaction. Thermodynamic analysis of the autothermal system revealed that high feed temperature, high reaction temperature, and low pressure are the most beneficial conditions for generating a high yield of hydrogen. The proposed process was simulated to assess its feasibility using kinetic parameters obtained from experimental data in the literature [27]. An optimization problem to minimize the reactor length in designing the proposed reactor was developed. The reactor design produces a high yield of hydrogen while maintaining the reaction temperature within the desired range. Adjusting the air flow rate at distribution points along the reactor to maintain peak temperatures at predetermined levels was shown to provide good load flexibility for variations in ammonia flow rate. • Hydrogen production from ammonia by integrating ammonia decomposition and ammonia oxidation was proposed. • Thermodynamic analysis of the ammonia autothermal reforming process was performed. • A new ammonia autothermal reformer with an air side stream distribution was proposed and optimized. • The reactor has good load flexibility for variations in ammonia flow rate. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the effects of flavonoid, which is a product of citrus production, on blood parameters and HSP 70 concentration in quails applied at thermoneutral and heat stress. In this study, 160 quails (Coturnix coturnix japonica, male), 6 wk old and 150-200 g live weight, were housed in cages for 1 wk of exercise and 5 wk of trial period. The study design consists of 4 groups of 40 animals and 4 subgroups with 10 animals in each group. Thermoneutral (24 ± 0.1 ° C) groups are NC (0 g hesperidin/kg basal feed) and NHES3 (3 g hesperidin/kg basal feed) and heat stress (34 ± 0.1 °C) groups are HC (0 g hesperidin/kg basal feed) and HHES3 (3 g hesperidin/kg basal feed) were randomly generated. In the case of heat stress, pO2, pH, HCO3, Cl concentrations decreased in the HHES3 group compared to the HC group (P<0.05). ALP enzyme concentration showed a significant decrease in the HHES3 group compared to the HC group in the heat stress condition. Heat shock protein (HSP70) protein level increased in blood serum, kidney, liver and thigh tissues in HC group with cellular stress during heat stress; however, HSP70 concentration decreased significantly in the HHES3 group. As a result, positive effects of hesperidin supplementation in the diet were found in both heat stress and thermoneutral conditions. [ABSTRACT FROM AUTHOR]

Lipoprotein lipase (LPL) is secreted into the interstitial spaces by parenchymal cells and then transported into capillaries by GPIHBP1. LPL carries out the lipolytic processing of triglyceride (TG)-rich lipoproteins (TRLs), but the tissue-specific regulation of LPL is incompletely understood. Plasma levels of TG hydrolase activity after heparin injection are often used to draw inferences about intravascular LPL levels, but the validity of these inferences is unclear. Moreover, plasma TG hydrolase activity levels are not helpful for understanding LPL regulation in specific tissues. Here, we sought to elucidate LPL regulation under thermoneutral conditions (30°C). To pursue this objective, we developed an antibody-based method to quantify (in a direct fashion) LPL levels inside capillaries. At 30°C, intracapillary LPL levels fell sharply in brown adipose tissue (BAT) but not heart. The reduced intracapillary LPL levels were accompanied by reduced margination of TRLs along capillaries. ANGPTL4 expression in BAT increased fourfold at 30°C, suggesting a potential explanation for the lower intracapillary LPL levels. Consistent with that idea, Angptl4 deficiency normalized both LPL levels and TRL margination in BAT at 30°C. In Gpihbp1-/- mice housed at 30°C, we observed an ANGPTL4- dependent decrease in LPL levels within the interstitial spaces of BAT, providing in vivo proof that ANGPTL4 regulates LPL levels before LPL transport into capillaries. In conclusion, our studies have illuminated intracapillary LPL regulation under thermoneutral conditions. Our approaches will be useful for defining the impact of genetic variation and metabolic disease on intracapillary LPL levels and TRL processing. [ABSTRACT FROM AUTHOR]

Typical vivarium temperatures (20-26°C) induce facultative thermogenesis in mice, a process attributable in part to uncoupling protein-1 (UCP1). The impact of modest changes in housing temperature on whole body and adipose tissue energetics in mice remains unclear. Here, we determined the effects of transitioning mice from 24°C to 30° C on total energy expenditure and adipose tissue protein signatures. C57BL/6J mice were housed at 24°C for 2 wk and then either remained at 2°C (n = 16/group, 8M/8F) or were transitioned to 30°C (n = 16/group, 8M/8F) for 4 wk. Total energy expenditure and its components were determined by indirect calorimetry. Interscapular brown adipose tissue (iBAT) and inguinal white adipose tissue (iWAT) proteins were quantified by Western blot and quantitative proteomics. Transitioning from 24°C to 30°C reduced total energy expenditure in both male (-25%) and female (-16%) mice, which was attributable to lower basal energy expenditure in males (-36%) and females (-40%). Total iBAT UCP1 protein content was 50% lower at 30°C compared with 24°C, whereas iWAT UCP1 protein content was similar between conditions. iBAT UCP1 protein content remained 20-fold greater than iWAT at 30°C. In iBAT and iWAT, 183 and 41 proteins were differentially expressed between 24°C and 30°C, respectively. iWAT proteins (257) differentially expressed between sexes at 30°C were not differentially expressed at 24°C. Thus, 30°C housing lowers total energy expenditure of mice when compared with an ambient temperature (24°C) that falls within the National Research Council's guidelines for housing laboratory mice. Lower iBAT UCP1 content accompanied chronic housing at 30°C. Furthermore, housing temperature influences sexual dimorphism in the iWAT proteome. These data have implications regarding the optimization of preclinical models of human disease. [ABSTRACT FROM AUTHOR]

Bone marrow adipose tissue (BMAT) levels are higher in distal femur metaphysis of female mice housed at thermoneutral (32°C) than in mice housed at 22°C, as are abdominal white adipose tissue (WAT) mass, and serum leptin levels. We performed two experiments to explore the role of increased leptin in temperature-enhanced accrual of BMAT. First, we supplemented 6-week-old female C57BL/6J (B6) mice with leptin for 2 weeks at 10 µg/d using a subcutaneously implanted osmotic pump. Controls consisted of ad libitum (ad lib) fed mice and mice pair fed to match food intake of leptin-supplemented mice. The mice were maintained at 32°C for the duration of treatment. At necropsy, serum leptin in leptin-supplemented mice did not differ from ad lib mice, suggesting suppression of endogenous leptin production. In support, Ucp1 expression in BAT, percent body fat, and abdominal WAT mass were lower in leptin-supplemented mice. Leptin-supplemented mice also had lower BMAT and higher bone formation in distal femur metaphysis compared to the ad lib group, changes not replicated by pair-feeding. In the second experiment, BMAT response was evaluated in 6-week-old female B6 wild type (WT), leptin-deficient ob/ob and leptin-treated (0.3 mg/d) ob/ob mice housed at 32°C for the 2-week duration of the treatment. Compared to mice sacrificed at baseline (22°C), BMAT increased in ob/ob mice as well as WT mice, indicating a leptin independent response to increased temperature. However, infusion of ob/ob mice with leptin, at a dose rate having negligible effects on either energy metabolism or serum leptin levels, attenuated the increase in BMAT. In summary, increased housing temperature and increased leptin have independent but opposing effects on BMAT in mice. [ABSTRACT FROM AUTHOR]

Bone marrow adipose tissue (BMAT) levels are higher in distal femur metaphysis of female mice housed at thermoneutral (32°C) than in mice housed at 22°C, as are abdominal white adipose tissue (WAT) mass, and serum leptin levels. We performed two experiments to explore the role of increased leptin in temperature-enhanced accrual of BMAT. First, we supplemented 6-week-old female C57BL/6J (B6) mice with leptin for 2 weeks at 10 µg/d using a subcutaneously implanted osmotic pump. Controls consisted of ad libitum (ad lib) fed mice and mice pair fed to match food intake of leptin-supplemented mice. The mice were maintained at 32°C for the duration of treatment. At necropsy, serum leptin in leptin-supplemented mice did not differ from ad lib mice, suggesting suppression of endogenous leptin production. In support, Ucp1 expression in BAT, percent body fat, and abdominal WAT mass were lower in leptin-supplemented mice. Leptin-supplemented mice also had lower BMAT and higher bone formation in distal femur metaphysis compared to the ad lib group, changes not replicated by pair-feeding. In the second experiment, BMAT response was evaluated in 6-week-old female B6 wild type (WT), leptin-deficient ob/ob and leptin-treated (0.3 μg/d) ob/ob mice housed at 32°C for the 2-week duration of the treatment. Compared to mice sacrificed at baseline (22°C), BMAT increased in ob/ob mice as well as WT mice, indicating a leptin independent response to increased temperature. However, infusion of ob/ob mice with leptin, at a dose rate having negligible effects on either energy metabolism or serum leptin levels, attenuated the increase in BMAT. In summary, increased housing temperature and increased leptin have independent but opposing effects on BMAT in mice.

Previous research has shown that cooling interventions can alter exercise performance, comfort, and rating of perceived exertion (RPE) in hot environments but less is known about the efficacy of cooling strategies in thermoneutral environments. The purpose of this investigation was to examine the physiological and perceptual effects of a cooling garment worn during a 10-km performance trial in a thermoneutral environment. Eight males (mean age ± SD = 22 ± 2 years) and five females (age = 24 ± 4 years) completed two 10-km performance trials separated by at least 48 hours on a cycle ergometer in a thermoneutral environment (24°C, 48% relative humidity). Time to completion, heart rate, oxygen consumption (...O2), power (W), percentage of physical working capacity at fatigue threshold (PWCFT), and RPE were measured at 10% intervals. There was no significant difference between the cooling (23.8 ± 5.5 minutes) and non-cooling (23.5 ± 5.1 minutes) conditions for time to completion. All variables increased similarly during both performance trials. The cooling garment had no effect on the 10-km performance trial time to completion in a thermoneutral environment. Additionally, PWCFT tracked the changes in work output and local muscle fatigue that were not as apparent as the heart rate, ...O2, and RPE responses that may have reflected pacing strategies. [ABSTRACT FROM AUTHOR]

Increasing whole‐body energy expenditure via the pharmacological activation of uncoupling protein 1 (UCP1)‐dependent brown adipose tissue (BAT) thermogenesis is a promising weight management strategy, yet most therapeutics studied in rodents to date either induce compensatory increases in energy intake, have thermogenic effects that are confounded by sub‐thermoneutral housing temperatures or are not well tolerated in humans. Here, we sought to determine whether the non‐invasive topical application of the pharmacological cold mimetic and transient receptor potential (TRP) cation channel subfamily M member 8 (TRPM8) agonist L‐menthol (MNTH), could be used to stimulate BAT thermogenesis and attenuate weight gain in mice housed at thermoneutrality. Using three different strains of mice and multiple complimentary approaches to quantify thermogenesis in vivo, coupled with ex vivo models to quantify direct thermogenic effects, we were able to convincingly demonstrate the following: (1) acute topical MNTH application induces BAT thermogenesis in a TRPM8‐ and UCP1‐dependent manner; (2) MNTH‐induced BAT thermogenesis is sufficient to attenuate weight gain over time without affecting energy intake in lean and obese mice; (3) the ability of topical MNTH application to stimulate BAT thermogenesis is mediated, in part, by a central mechanism involving the release of norepinephrine. These data collectively suggest that topical application of MNTH may be a promising weight management strategy. [ABSTRACT FROM AUTHOR]

Methane tri-reforming combines steam reforming, dry reforming and partial oxidation of methane in a single reactor. The heat generated by the exothermic partial oxidation of methane can be used to supply the energy for the other two endothermic reactions (dry and steam reforming of methane). The thermoneutral condition allows the use of a tri-reformer with a simpler reactor structure since no external heat supply is necessary. Thermodynamic analysis of the thermoneutral reactor was performed using Gibbs free energy minimization approach. Conventional tri-reformers have heat and mass management problems. We developed a novel tri-reformer concept that utilizes proper distribution of O 2 gas to the reactor to address the problems. The optimization of the proposed reactor was performed with the objective function of minimizing total annual cost. Maintaining the peak temperatures by adjusting the O 2 flow rate at the distribution point along the reactor was shown to provide good load flexibility for the change in methane flow rate. [Display omitted] • Thermodynamic analysis of thermoneutral tri-reformer was performed. • A new tri-reformer with side stream distribution of O2 was proposed. • The reactor can deal with the heat and mass management problem of tri-reformer. • The reactor gives good load flexibility for the change in feed flow rate. [ABSTRACT FROM AUTHOR]

Growing female mice housed at room temperature (22°C) weigh the same but differ in body composition compared to mice housed at thermoneutrality (32°C). Specifically, mice housed at room temperature have lower levels of white adipose tissue (WAT). Additionally, bone marrow adipose tissue (bMAT) and cancellous bone volume fraction in distal femur metaphysis are lower in room temperature-housed mice. The metabolic changes induced by sub-thermoneutral housing are associated with lower leptin levels in serum and higher levels of Ucp1 gene expression in brown adipose tissue. Although the precise mechanisms mediating adaptation to sub-thermoneutral temperature stress remain to be elucidated, there is evidence that increased sympathetic nervous system activity acting via β-adrenergic receptors plays an important role. We therefore evaluated the effect of the non-specific β-blocker propranolol (primarily β1 and β2 antagonist) on body composition, femur microarchitecture, and bMAT in growing female C57BL/6 mice housed at either room temperature or thermoneutral temperature. As anticipated, cancellous bone volume fraction, WAT and bMAT were lower in mice housed at room temperature. Propranolol had small but significant effects on bone microarchitecture (increased trabecular number and decreased trabecular spacing), but did not attenuate premature bone loss induced by room temperature housing. In contrast, propranolol treatment prevented housing temperature-associated differences in WAT and bMAT. To gain additional insight, we evaluated a panel of genes in tibia, using an adipogenesis PCR array. Housing temperature and treatment with propranolol had exclusive as well as shared effects on gene expression. Of particular interest was the finding that room temperature housing reduced, whereas propranolol increased, expression of the gene for acetyl-CoA carboxylase (Acacb), the rate-limiting step for fatty acid synthesis and a key regulator of β-oxidation. Taken together, these findings provide evidence that increased activation of β1 and/or β2 receptors contributes to reduced bMAT by regulating adipocyte metabolism, but that this pathway is unlikely to be responsible for premature cancellous bone loss in room temperature-housed mice.

Physiological adaptations during heat exposure are critical in pregnancy. Maternal thermoregulation has to accommodate the increased metabolic load of the developing fetus. Here, we assess the consequences of intermittent heat exposure, as occurs in heat waves, for maternal adaptations during pregnancy, and chronic feto-placental outcomes. Following timed mating, C57BL/6J mice were allocated to either standard animal housing temperature conditions (SH) or housing at a temperature within the thermoneutral zone (TNZ). A subset of the TNZ group was exposed to 37 °C for 8 h a day from E15.5 to E17.5 to simulate a heat wave (HW). Maternal weight gain, food intake, rectal temperature, and nesting behaviors were measured across gestation. Fetal and placental tissues were collected at E18.5. With heat exposure, maternal rectal temperature increased while food intake and nest complexity decreased. Maternal daily weight gain initially decreased due to heat exposure, but on the last day of exposure, it was comparable to the other experimental groups. These maternal responses during heat exposure impacted on the fetus, with restrictions in placental and fetal development evident just before birth. Thus, the vascular portion of the placenta, and the relative fetal head size, was smaller. Furthermore, SH and TNZ animals demonstrated distinct differences in food intake and nesting behavior during pregnancy, reinforcing the need for caution in extrapolating from animal models to humans when housing occurs outside of thermoneutral zone conditions. This study highlights the direct effects of temperature conditions on health in pregnancy and provides a foundation for future studies to investigate fetal health consequences that are associated with intermittent heat exposure. [ABSTRACT FROM AUTHOR]

Obesity and its metabolic sequelae are implicated in dysfunction of the somatosensory, sympathetic, and hypothalamic systems. Because these systems contribute to integrative regulation of energy expenditure (EE) and energy intake (EI) in response to ambient temperature (Ta) changes, we hypothesized that diet-induced obesity (DIO) disrupts Ta-associated EE-EI coupling. C57BL/6N male mice were fed a high-fat diet (HFD; 45% kcal) or low-fat diet (LFD; 10% kcal) for ∼9.5 wk; HFD mice were then split into body weight (BWT) quartiles (n = 8 each) to study DIO-low gainers (Q1) versus -high gainers (Q4). EI and indirect calorimetry (IC) were measured over 3 days each at 10°C, 20°C, and 30°C. Responses did not differ between LFD, Q1, and Q4; EI and BWT-adjusted EE increased rapidly when transitioning toward 20°C and 10°C. In all groups, EI at 30°C was not reduced despite lower EE, resulting in positive energy balance and respiratory exchange ratios consistent with increased de novo lipogenesis, energy storage, and relative hyperphagia. We conclude that 1) systems controlling Ta-dependent acute EI/EE coupling remained intact in obese mice and 2) rapid coupling of EI/EE at cooler temperatures is an important adaptation to maintain energy stores and defend body temperature, but less critical at thermoneutrality. A post hoc analysis using digestible EI plus IC-calculated EE suggests that standard IC assumptions for EE calculation require further validation in the setting of DIO. The experimental paradigm provides a platform to query the hypothalamic, somatosensory, and sympathetic mechanisms that drive Ta-associated EI/EE coupling. [ABSTRACT FROM AUTHOR]

Growing female mice housed at room temperature (22°C) weigh the same but differ in body composition compared to mice housed at thermoneutrality (32°C). Specifically, mice housed at room temperature have lower levels of white adipose tissue (WAT). Additionally, bone marrow adipose tissue (bMAT) and cancellous bone volume fraction in distal femur metaphysis are lower in room temperature-housed mice. The metabolic changes induced by sub-thermoneutral housing are associated with lower leptin levels in serum and higher levels of Ucp1 gene expression in brown adipose tissue. Although the precise mechanisms mediating adaptation to sub-thermoneutral temperature stress remain to be elucidated, there is evidence that increased sympathetic nervous system activity acting via β-adrenergic receptors plays an important role. We therefore evaluated the effect of the non-specific β-blocker propranolol (primarily β1 and β2 antagonist) on body composition, femur microarchitecture, and bMAT in growing female C57BL/6 mice housed at either room temperature or thermoneutral temperature. As anticipated, cancellous bone volume fraction, WAT and bMAT were lower in mice housed at room temperature. Propranolol had small but significant effects on bone microarchitecture (increased trabecular number and decreased trabecular spacing), but did not attenuate premature bone loss induced by room temperature housing. In contrast, propranolol treatment prevented housing temperature-associated differences in WAT and bMAT. To gain additional insight, we evaluated a panel of genes in tibia, using an adipogenesis PCR array. Housing temperature and treatment with propranolol had exclusive as well as shared effects on gene expression. Of particular interest was the finding that room temperature housing reduced, whereas propranolol increased, expression of the gene for acetyl-CoA carboxylase (Acacb), the rate-limiting step for fatty acid synthesis and a key regulator of β-oxidation. Taken together, these findings provide evidence that increased activation of β1 and/or β2 receptors contributes to reduced bMAT by regulating adipocyte metabolism, but that this pathway is unlikely to be responsible for premature cancellous bone loss in room temperature-housed mice. [ABSTRACT FROM AUTHOR]

Keywords: brown adipose tissue; cold exposure; obesity; pre-clinical model; thermogenesis; thermoneutral EN brown adipose tissue cold exposure obesity pre-clinical model thermogenesis thermoneutral 719 721 3 02/15/22 20220215 NES 220215 Obesity is defined as a surfeit of adipose tissue, which develops over time when energy consumption chronically exceeds expenditure. Of course, measuring BAT function I in vivo i is a non-trivial endeavour; future studies could help address this point using thermal imaging of BAT surface temperature in an effort optimize the ability of ICE protocols in activating classical brown fat. Given that adult humans have some metabolically active brown fat, it is possible that cold-induced BAT activation could be therapeutically relevant in people living with obesity and related co-morbidities (Ivanova & Blondin, 2021). [Extracted from the article]

The effects of nano-emulsified vegetable oil (NEVO) and betaine (BET) supplements on growth performance and meat qualities of broilers reared under cyclic heat stress (HS) were investigated. Two hundred and eighty-eight mixed-sex broilers at 21 d were randomly distributed to a 2 × 3 factorial arrangement of treatments formed by two environmental temperatures (thermoneutral (TN; 24 ± 1 °C) and cyclic high-temperature (HT; 35 ± 1 °C)) and three dietary treatments (control (CON), NEVO, and BET). The cumulative performance (21–35 d) revealed a reduction in average daily gain (ADG) (p < 0.05) in the CON compared to NEVO. NEVO and BET groups had a better feed conversion ratio (FCR) and performance efficiency factor (PEF) compared with the CON (p < 0.001, p < 0.01, respectively). The environmental temperature affected daily feed intake (DFI), ADG, FCR, and PEF. The addition of BET improved breast fillets yield, temperature, pH15min, and pH24hr (p < 0.05) in comparison with the CON. Moreover, the TN group had lower fillet temperature and higher pH15min compared to the HT. Moreover, HT increased shear force (SF), hardness, springiness, cohesiveness, and chewiness of the fillets compared to TN. In conclusion, dietary supplementation with BET and NEVO could effectively improve performance parameters and meat characteristics under HS conditions.

Key points: Mice are commonly housed at room temperatures below their thermoneutral zone meaning they are exposed to chronic thermal stress.Endurance exercise induces browning and mitochondrial biogenesis in white adipose tissue of rodents, but there are conflicting reports of this phenomenon in humans.We hypothesized that the ambient room temperature at which mice are housed could partially explain these discrepant reports between humans and rodents.We housed mice at room temperature or thermoneutrality and studied their physiological responses to acute and chronic exercise. We found that thermoneutral housing altered running behaviour and glucose homeostasis, and further, that exercise‐induced markers of mitochondrial biogenesis and the browning of white adipose tissue were reduced in mice housed at thermoneutrality. Mice are often housed at temperatures below their thermoneutral zone resulting in compensatory increases in thermogenesis. Despite this, many studies report housing mice at room temperature (RT), likely for the convenience of the researchers studying them. As such, the conflicting reports between humans and rodents regarding the ability of exercise to increase mitochondrial and thermogenic markers in white adipose tissue may be explained by the often‐overlooked variable, housing temperature. To test this hypothesis, we housed male C57BL/6 mice at RT (22°C) or thermoneutrality (TN) (29°C) with or without access to a voluntary running wheel for 6 weeks or subjected them to an acute exhaustive bout of treadmill running. We examined the gene expression and protein content of select mitochondrial and thermogenic markers in skeletal muscle, epididymal white adipose tissue (eWAT), inguinal white adipose tissue (iWAT) and brown adipose tissue (BAT). We also assessed adipocyte morphology and indices of glucose homeostasis. Housing temperature influenced glucose tolerance and insulin action in vivo, yet the beneficial effects of exercise, both acute and chronic, remained intact in eWAT, BAT and skeletal muscle irrespective of housing temperature. Housing mice at TN led to an attenuation of some of the effects of exercise on iWAT. Collectively, we present data characterizing the acute and chronic metabolic adaptations to exercise at different housing temperatures and demonstrate, for the first time, that temperature influences the ability of exercise to increase markers of mitochondrial biogenesis and the browning of white adipose tissue. Key points: Mice are commonly housed at room temperatures below their thermoneutral zone meaning they are exposed to chronic thermal stress.Endurance exercise induces browning and mitochondrial biogenesis in white adipose tissue of rodents, but there are conflicting reports of this phenomenon in humans.We hypothesized that the ambient room temperature at which mice are housed could partially explain these discrepant reports between humans and rodents.We housed mice at room temperature or thermoneutrality and studied their physiological responses to acute and chronic exercise. We found that thermoneutral housing altered running behaviour and glucose homeostasis, and further, that exercise‐induced markers of mitochondrial biogenesis and the browning of white adipose tissue were reduced in mice housed at thermoneutrality. [ABSTRACT FROM AUTHOR]

The thermodynamic features of hydrogen production via chemical looping reforming of waste cooking oil were studied at atmospheric pressure using Gibbs free energy minimization, accounting for the possibility of coke formation. The synthesis gas composition was determined as a function of reforming temperature (400–1000 °C), steam to carbon ratio (S/C, 1–14) and NiO to carbon ratio (NiO/C, 0–2). To evaluate the thermodynamically plausible products, the study started with an expanded product set of approximately 30 by-products. The results show that coke formation can be thermodynamically inhibited by increasing the S/C ratio and/or the NiO/C ratio. The conditions that maximize hydrogen production, minimize methane and carbon monoxide content as well as avoid coke formation at thermoneutral conditions were found to be S/C = 5, T = 600 °C and NiO/C = 0.493. Under these conditions, a hydrogen yield of 144.3 mol/kg of soybean waste cooking oil can be obtained, which appears to be an attractive result for starting experimental research.

The effects of dietary supplemental lysophospholipids (LPLs) and vitamin C (VC) on performance, activity of antioxidant enzymes, and thyroid hormones of broiler chickens reared under thermoneutral and high ambient temperatures were evaluated. A total of 1,680 broiler chicks (Cobb 500) in finishing rearing period (days 21–38 of age) were allotted to two groups: thermoneutral (TN) and heat stress (HS). In the TN group, 480 chicks were subjected to four treatments with four replicates (n = 30) and maintained in usual ambient temperature (24 ± 1°C). In HS group, the remaining 1,200 chicks were subjected to four treatments with 10 replicates (n = 30) and exposed to high ambient temperature (34 ± 1°C for 8 hr daily). In both groups, four iso‐caloric and iso‐nitrogenous experimental diets based on a 2 × 2 factorial arrangements including supplemental LPLs (0 or 1,000 mg/kg) and VC (0 or 500 mg/kg) were formulated and used. Supplemental LPLs decreased (p < 0.05) body weight gain and increased FCR in the TN and HS groups. In the TN group, increased (p < 0.05) serum glucose was observed in chickens fed with dietary supplemental VC. In the HS group, decreased (p < 0.05) total protein concentration was detected in birds fed with supplemental LPLs. In both TN and HS groups, decreased (p < 0.05) uric acid concentration was detected in chicks fed with the VC‐supplemented diets. A significant (p < 0.05) interaction between LPLs and VC on lactate concentration in the TN group was observed. In the HS group, decreased breast malondialdehyde concentration was detected in birds fed with the VC‐supplemented diet. In the TN group, increased serum total antioxidant status was detected in birds fed with the LPLs‐supplemented diet. In conclusion, LPLs improved oxidative stability and increased the antioxidant capacity of the serum. In addition, vitamin C modified heat stress and reduced lipid peroxidation. [ABSTRACT FROM AUTHOR]

Objectives The laboratory mouse is presently the most common model for examining mechanisms of human physiology and disease. Housing temperatures can have a large impact on the outcome of such experiments and on their translatability to the human situation. Humans usually create for themselves a thermoneutral environment without cold stress, while laboratory mice under standard conditions (≈20° C) are under constant cold stress. In a well-cited, theoretical paper by Speakman and Keijer in Molecular Metabolism, it was argued that housing mice under close to standard conditions is the optimal way of modeling the human metabolic situation. This tenet was mainly based on the observation that humans usually display average metabolic rates of about 1.6 times basal metabolic rate. The extra heat thereby produced would also be expected to lead to a shift in the ‘lower critical temperature’ towards lower temperatures. Methods To examine these tenets experimentally, we performed high time-resolution indirect calorimetry at different environmental temperatures on mice acclimated to different housing temperatures. Results Based on the high time-resolution calorimetry analysis, we found that mice already under thermoneutral conditions display mean diurnal energy expenditure rates 1.8 times higher than basal metabolism, remarkably closely resembling the human situation. At any temperature below thermoneutrality, mice metabolism therefore exceeds the human equivalent: Mice under standard conditions display energy expenditure 3.1 times basal metabolism. The discrepancy to previous conclusions is probably attributable to earlier limitations in establishing true mouse basal metabolic rate, due to low time resolution. We also found that the fact that mean energy expenditure exceeds resting metabolic rate does not move the apparent thermoneutral zone (the lower critical temperature) downwards. Conclusions We show that housing mice at thermoneutrality is an advantageous step towards aligning mouse energy metabolism to human energy metabolism. [ABSTRACT FROM AUTHOR]

Solid oxide electrolyzer (SOE) can operate in co-electrolysis mode of H2O and CO2 because of the high operating temperature and the nickel-based fuel electrode material. In this configuration, the fuel electrode is fed with a mix of steam and carbon dioxide that is converted through electrolysis reactions into a syngas that can be further upgraded to other carbon fuels. This technology can lead to interesting scenarios in the field of energy storage and CO2 reuse. SOE performance in terms of syngas quality and chemical equilibrium is presented in this study. An experimental test on a four-cell stack was performed to evaluate which are the effects of inlet gas composition and current density on the output syngas composition and on the thermal balance of the stack. Results were analyzed with the support of a thermodynamic model that aims to demonstrate that equilibrium condition is reached within the stack for all the involved reactions including reverse water shift. Also, we show that there is a direct relation between inlet and outlet compositions. For each composition, current density for thermoneutral condition was calculated obtaining values in the range of 377-493 mA/cm2 depending on the composition. Such results permit to study SOE integration in a complete process for energy and CO2 storage. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Solid oxide fuel cells remain at the forefront of research into electrochemical energy conversion technology. More recent interest has focused on operating in electrolyser mode to convert steam or carbon dioxide into hydrogen or carbon monoxide, respectively. The mechanism of these reactions is not fully understood, particularly when operated in co-electrolysis mode using both steam and CO 2 . This contribution reports the use of a thermal camera to directly observe changes in the cell temperature during operation, providing a remote, non-contact and highly sensitive method for monitoring an operational cell. [ABSTRACT FROM AUTHOR]

Este experimento foi realizado para avaliar níveis de energia metabolizável (EM) (2850, 2921, 3000, 3075 e 3150 kcal/kg) para pintos de corte, machos, de 1 a 21 dias de idade, mantidos em ambiente de conforto térmico. Quatrocentos e cinqüenta pintos, machos, com 44±0,2 g de peso inicial médio, foram distribuídos em delineamento experimental inteiramente casualizado, com cinco tratamentos, nove repetições e dez aves por unidade experimental. O nível de EM da ração influenciou o ganho de peso médio diário e o consumo de energia metabolizável, que aumentaram, e a conversão alimentar, que reduziu linearmente com o aumento do nível de energia da ração. O nível de EM da ração influenciou as taxas de deposições de proteína e gordura na carcaça e o peso de gordura abdominal, que aumentaram linearmente, enquanto o rendimento de carcaça não foi influenciado. O nível de 3075 kcal EM na ração proporcionou o melhor desempenho das aves mantidas em condição de conforto térmico, na fase de 1 a 21 dias de idade.This experiment was carried out to evaluate the metabolizable energy (ME) (2850, 2921, 3000, 3075 e 3150 kcal/kg) levels for male broilers from 1 to 21 days of age, maintained in thermoneutralenvironment. Four hundred and fifty chicks, male, with average initial 44±0.2 g LW, were allotted to a completely randomized experimental design with five treatments, nine replicates and ten animals per experimental unit. The ME level of the diet affected the average weight gain and the ME intake, which increased, and the feed:gain ratio, that linearly decreased with the increase of the dietary energy level. The dietary energy level affected the fat and protein deposition rates of the carcass and abdominal fat weight, which linearly increased, while the carcass yield was not affected. The dietary level of 3075 kcal ME promoted the best broiler performance, from 1 to 21 days of age, maintained under a thermoneutralenvironment.

Obstructive sleep apnea causes intermittent hypoxia (IH) during sleep and is associated with dysregulation of glucose metabolism. We developed a novel model of clinically realistic IH in mice to test the hypothesis that IH causes hyperglycemia, glucose intolerance, and insulin resistance via activation of the sympathetic nervous system. Mice were exposed to acute hypoxia of graded severity (21, 14, 10, and 7% O2) or to IH of graded frequency [oxygen desaturation index (ODI) of 0, 15, 30, or 60, SpO2 nadir 80%] for 30 min to measure levels of glucose fatty acids, glycerol, insulin, and lactate. Glucose tolerance tests and insulin tolerance tests were then performed under each hypoxia condition. Next, we examined these outcomes in mice that were administered phentolamine (α-adrenergic blockade) or propranolol (β-adrenergic blockade) or that underwent adrenal medullectomy before IH exposure. In all experiments, mice were maintained in a thermoneutral environment. Sustained and IH induced hyperglycemia, glucose intolerance, and insulin resistance in a dose-dependent fashion. Only severe hypoxia (7% O2) increased lactate, and only frequent IH (ODI 60) increased plasma fatty acids. Phentolamine or adrenal medullectomy both prevented IH-induced hyperglycemia and glucose intolerance. IH inhibited glucose-stimulated insulin secretion, and phentolamine prevented the inhibition. Propranolol had no effect on glucose metabolism but abolished IH-induced lipolysis. IH-induced insulin resistance was not affected by any intervention. Acutely hypoxia causes hyperglycemia, glucose intolerance, and insulin resistance in a dose-dependent manner. During IH, circulating catecholamines act upon α-adrenoreceptors to cause hyperglycemia and glucose intolerance. [ABSTRACT FROM AUTHOR]

Sprint (high-intensity) exercise performance is reduced when immediately preceded by cold water immersion ( CWI). We aimed to investigate whether this performance effect could be attenuated by combining an active recovery (arm exercise) with hip-level CWI, and whether this attenuation may be related to an effect on core temperature ( Tcore). Participants ( n = 8) completed three Wingate tests before ( Ex1) and after ( Ex2) four different 30-min recovery interventions: CWI at 15 °C ( CW15), arm exercise during CWI at 15 °C (CW15+ AE), arm exercise during thermoneutral immersion at 34 °C ( TW34+ AE) and non-immersed arm exercise ( AE). After AE and TW34+ AE, performance during Ex2 was not different from Ex1; while after CW15+ AE and CW15, performance was reduced by 4.9% and 7.6%, respectively. Arm exercise maintained Tcore during recovery in CW15+ AE, while it declined to a larger extent upon commencement of Ex2 (−0.9 °C) when compared with CW15 (−0.6 °C). This suggests similar leg muscle cooling during recovery in CW15 and CW15+ AE. Without any other significant effects (e.g., on blood lactate), these data suggest that the improvement in sprint performance following an active CWI recovery, over CWI alone, may be related to maintained Tcore and its effect on neurophysiological mechanisms that drive muscle activation, but not by reduced muscle cooling. [ABSTRACT FROM AUTHOR]

Highlights: [•] Thermodynamic analysis of steam and autothermal reforming of soybean frying oil. [•] Soybean frying oil is considered as a mixture of triglycerides. [•] Coke formation is avoided by increasing the temperature and/or the S/C ratio. [•] Optimum steam reforming conditions are 650–850°C and S/C ratio around 5. [•] Optimum autothermal conditions are 600–800°C, S/C of 3–5 and O/C of 0.391–0.455. [ABSTRACT FROM AUTHOR]

Abstract: A thermodynamic analysis of hydrogen production via steam and autothermal reforming of beef tallow has been carried out via the Gibbs free energy minimization method. Equilibrium calculations are performed at atmospheric pressure with a wide range of temperatures (400–1200°C), steam-to-beef tallow ratios (1–15) and oxygen-to-beef tallow ratios (0.0–2.0). The results show that the optimum conditions for steam reforming can be achieved at reforming temperatures between 700°C and 900°C and a steam-to-beef tallow ratio of approximately 5. Optimal operating conditions of T =700°C and a steam-to-beef tallow ratio of 5 are proposed. With this condition, a hydrogen yield of 170moles/kg beef tallow and a CO concentration in the synthesis gas of 4.77% with a trace content of CH4 (0.01%) can be obtained without coke formation. The most favorable conditions for hydrogen production from autothermal systems are achieved at the temperature, steam-to-beef tallow ratio and oxygen-to-beef tallow ratio of 600–800°C, 3–5 and 0.0–0.45, respectively. Thermoneutral conditions can be accomplished with an oxygen-to-beef tallow ratio of 0.384–0.427. The recommended conditions are a steam-to-beef tallow ratio of 5, T =600°C and an oxygen-to-beef tallow ratio of 0.422. Under these conditions, 150moles H2/kg beef tallow can be produced with only 2.92% CO and 0.07% CH4 in the synthesis gas. [Copyright &y& Elsevier]

Abstract: It has been argued that mice should be housed at 30°C to best mimic the thermal conditions experienced by humans, and that the current practice of housing mice at 20–22°C impairs the suitability of mice as a model for human physiology and disease. In the current paper we challenge this notion. First, we show that humans routinely occupy environments about 3°C below their lower critical temperature (T lc), which when lightly clothed is about 23°C. Second, we review the data for the T lc of mice. Mouse T lc is dependent on body weight and about 26–28°C for adult mice weighing >25g. The equivalent temperature to that normally experienced by humans for most single housed adult mice is therefore 23–25°C. Group housing or providing the mice with bedding and nesting material might lower this to about 20–22°C, close to current standard practice. [Copyright &y& Elsevier]

Abstract: This study determined the potential for short-term adaptation to fescue toxicosis and heat stress in rats. Male CD outbred rats (n=24) were implanted with temperature transmitters (Respironics, Bend, OR) to measure core temperature (Tc) and general activity. All rats were initially fed diets with ground, uninfected tall fescue seed (E−) and exposed to 21°C (thermoneutral, TN) to establish baseline values. In Period 1, all groups were maintained at TN for 7 days, with one group fed a diet containing ground, endophyte-infected tall fescue seed (E+, approximately 165μg ergovaline/kg BW/d) and two groups fed E− diet. Ergovaline is thought to be the primary toxin responsible for many symptoms associated with fescue toxicosis. Period 1 was followed by 7 days at 31°C (heat stress, HS, Period 2) on the same diets. All animals were fed E− diet during the second 7 day of HS (Period 3). In the final 7 day (Period 4), E+ diet was returned to the original group and fed to one of the previously E− groups, with the third group remaining on E− diet. A 40% decrease in FI occurred with E+ treatment at TN (P<0.05), with a comparable BW reduction (P<0.05) after 4 day. Both responses worsened during HS. Treatment with E+ in Period 4 indicated that FI and BW had not adapted to fescue toxicosis. A reduction in daily Tc occurred with E+ treatment at TN (P<0.05) followed by hyperthermia during the initial stage of HS (P<0.05). Although feed intake and growth rate showed no change over time, there was a reduction in fescue toxicosis-induced hyperthermia in the heat with repeat treatment. Conditioning animals to fescue toxicosis and heat stress prior to exposure may be beneficial in reducing impacts on thermal status of the animal. [Copyright &y& Elsevier]

Abstract: Dry autothermal reforming of ethanol can be used to produce a variety of value added products like hydrogen, syngas and also carbon (possible CNF). A thermodynamic analysis of dry autothermal reforming of ethanol has been carried out to locate the thermoneutral temperatures and product composition at those points at 1, 3, 6 and 9 bar reaction pressures. The variations of thermoneutral temperatures and individual product yields at those temperatures have been discussed to find the optimum operating parameters for desired product output from the process. The process operated at thermoneutral conditions can give useful products like hydrogen, syngas (of low ratio) and carbon (possibly CNFs) and also provide a way for CO2 sequestration using renewable ethanol fuel. A maximum of 2.58 moles of syngas of ratio 2.01 obtained at 1 bar, CER=1 and OER=0.5 along with 0.82 moles of carbon, 0.20 moles of CH4 and 0.89 moles of water for the thermoneutral temperature of 603.55°C was found to be the best operating thermoneutral point for value added product generation from this process. This study can be applied to a variety of fuels for producing value added products. [ABSTRACT FROM AUTHOR]

Abstract: In this work, thermodynamics was applied to investigate the glycerol autothermal reforming to generate hydrogen for fuel cell application. Equilibrium calculations employing the Gibbs free energy minimization were performed in a wide range of temperature (700–1000K), steam to glycerol ratio (1–12) and oxygen to glycerol ratio (0.0–3.0). Results show that the most favorable conditions for hydrogen production are achieved with the temperatures, steam to glycerol ratios and oxygen to glycerol ratios of 900–1000K, 9–12 and 0.0–0.4, respectively. Further, it is demonstrated that thermoneutral conditions (steam to glycerol ratio 9–12) can be obtained at oxygen to glycerol ratios of around 0.36 (at 900K) and 0.38–0.39 (at 1000K). Under these thermoneutral conditions, the maximum number of moles of hydrogen produced are 5.62 (900K) and 5.43 (1000K) with a steam to glycerol ratio of 12. Also, it should be noted that methane and carbon formation can be effectively eliminated. [Copyright &y& Elsevier]

Abstract: Flue gases from coal, gas, or oil-fired power stations, as well as from several heavy industries, such as the production of iron, lime and cement, are major anthropogenic sources of global CO2 emissions. The newly proposed process for syngas production based on the tri-reforming of such flue gases with natural gas could be an important route for CO2 emission avoidance. In addition, by combining the carbothermic reduction of iron oxide with the partial oxidation of the carbon source, an overall thermoneutral process can be designed for the co-production of iron and syngas rich in CO. Water-gas shift (WGS) of CO to H2 enables the production of useful syngas. The reaction process heat, or the conditions for thermoneutrality, are derived by thermochemical equilibrium calculations. The thermodynamic constraints are determined for the production of syngas suitable for methanol, hydrogen, or ammonia synthesis. The environmental and economic consequences are assessed for large-scale commercial production of these chemical commodities. Preliminary evaluations with natural gas, coke, or coal as carbon source indicate that such combined processes should be economically competitive, as well as promising significant fuel saving and CO2 emission avoidance. The production of ammonia in the above processes seems particularly attractive, as it consumes the nitrogen in the flue gases. [Copyright &y& Elsevier]

This study characterizes the responses, particularly diurnal variations, of thyroid hormones (TH) [3,5,3′-triiodothyronine (T3), thyroxine (T4), and T3:T4 ratio (T3/T4)] of Arbor Acres broilers to constant thermoneutral (TN) or warm cyclic (WC) temperatures. There existed distinct circadian variations—2 peaks in TH under the TN and WC conditions. The 2 peaks of T3, T4, and T3/T4 of the broilers occurred, respectively, at 0 and 16 h, 8 and 16 h, and 0 and 12 h under the TN condition; but at 0 and 12 h, 0 and 8 h, and 4 and 12 h under the WC conditions. During a 5-d heat exposure (HE) to the WC regimens, T3 and T4 showed continual decrease. The daily mean of T3 declined significantly (P < 0.05) on the first day of HE, whereas significant decrease of T4 (P < 0.05) occurred on the second day of HE. There was no signify- cant change in daily mean of T3/T4 during the same HE period. Hence, results of the study indicate that T3 provides a better heat stress indicator than T4. The nature of circadian variations in TH makes it necessary to collect blood samples more than once a day, e.g., 6 times at 0, 4, 8, 12, 16, and 20 h, to ensure full evaluation of hormonal responses of market-size broilers undergoing thermal challenges. [ABSTRACT FROM AUTHOR]

Objective: The objective of the study was to evaluate endothelial nitric oxide synthase concentration in the placenta, uterine, and umbilical vessels near term in an ovine model of intrauterine growth restriction induced by hyperthermia beginning in early gestation. Study design: Four pregnant ewes were exposed to hyperthermia conditions for 80 days beginning at 35 days gestation to induce intrauterine growth restriction. Four ewes were kept in ambient conditions as controls. Umbilical artery Doppler systolic to diastolic ratios were calculated. At 128 days gestation, fetal catheters were placed for aortic blood pressure measurements and blood gas determination. At 132 days gestation, fetal mean systemic blood pressure and gases were determined. Sheep placentomes, umbilical artery and vein, and uterine artery were assessed for endothelial nitric oxide synthase concentration and immunolocalization. Results: Compared with control pregnancies, the intrauterine growth restriction pregnancies showed: (1) reduced fetal and placental weights (P ≤ .01); (2) elevated systemic blood pressure (41 ± 1.53 mm Hg versus 44.3 ± 1.71 mm Hg; P ≤ .05) and systolic to diastolic ratios (3.0 ± 0.34 versus 3.8 ± 0.18; P ≤ .01); (3) reduced fetal O2 saturation (52.2 ± 7.03% versus 33.05 ± 10.98%; P ≤ .008); and (4) decreased endothelial nitric oxide synthase protein concentration in the umbilical artery (2.7-fold; P ≤ .01) and a trend for a decrease in the uterine artery (1.4-fold; P ≤ .1). Conclusion: We conclude that placental endothelial nitric oxide synthase protein concentration is increased near term in our ovine model of intrauterine growth restriction, and that this increase may be secondary to hypoxia. [ABSTRACT FROM AUTHOR]

Abstract: The cement and lime industries are major contributors to the anthropogenic CO2 emissions to the atmosphere. By combining the CO2-releasing calcination of CaCO3 with the CO2-consuming dry-reforming of CH4, and by further combining these endothermic reactions with the exothermic partial oxidation of CH4, a single thermo-neutral process can be designed for co-producing CaO and syngas in an authothermal reactor. Syngas can be further processed to H2, methanol, or Fischer–Tropsch chemicals. The conditions for thermo-neutrality are determined by thermo chemical equilibrium calculations. Such combined processes could achieve considerable CO2 emission avoidance as well as fuel saving relative to the conventional production of CaO and syngas. A preliminary evaluation indicates favorable economics for the co-production of CaO and hydrogen or methanol from CaCO3+O2+H2O and natural gas (NG) or coal. [Copyright &y& Elsevier]

Abstract: The treatment of flue gases from fossil fuel fired power stations by tri-reforming with natural gas or by coal gasification could become an attractive approach for converting the CO2, H2O, O2, and N2 contained in these flue gases via syngas processing into useful products, such as methanol, hydrogen, ammonia, or urea. The present study determines the constraints for achieving such thermochemical reactions under conditions of thermoneutrality, by reacting the flue gases with water, air, and natural gas or coal at 1000–1200K. The implications of such reactions are examined in terms of CO2 emission avoidance, fuel saving, economic viability, and exergy efficiency. [Copyright &y& Elsevier]

The role of skin temperature in reflex control of the active cutaneous vasodilator system was examined in six subjects during mild graded heat stress imposed by perfusing water at 34, 36, 38, and 40°C through a tube-lined garment. Skin sympathetic nerve activity (SSNA) was recorded from the peroneal nerve with microneurography. While monitoring esophageal, mean skin, and local skin temperatures, we recorded skin blood flow at bretylium-treated and untreated skin sites by using laser-Doppler velocimetry and local sweat rate by using capacitance hygrometry on the dorsal foot. Cutaneous vascular conductance (CVC) was calcu- lated by dividing skin blood flow by mean arterial pressure. Mild heat stress increased mean skin temperature by 0.2 or 0.3°C every stage, but esophageal and local skin temperature did not change during the first three stages. CVC at the bretylium tosylate-treated site (CVCBT) and sweat expulsion number increased at 38 and 40°C compared with 34°C (P < 0.05); however, CVC at the untreated site did not change. SSNA increased at 40°C (P < 0.05, different from 34°C). However, SSNA burst amplitude increased (P < 0.05), whereas SSNA burst duration decreased (P < 0.05), at the same time as we observed the increase in CVCBT and sweat expulsion number. These data support the hypothesis that the active vasodilator system is activated by changes in mean skin temperature, even at normal core temperature. and illustrate the intricate competition between active vasodilator and the vasoconstrictor system for control of skin blood flow during mild heat stress. [ABSTRACT FROM AUTHOR]

Background: Low back pain (LBP) is among the most common physical ailments and its chronic manifestation is a leading cause for disability worldwide. LBP is not attributable to a known diagnosis in 85% of the cases and therefore called chronic non-specific LBP (cnLBP). Passive immersion in warm water is commonly claimed to reduce muscular tension and pain, but not yet sufficiently investigated with regard to cnLBP. The current study compares three passive aquatic interventions regarding their effects on cnLBP: floating (resting in a supine immersed position on flotation devices), WATSU (a passive hands-on treatment, in which a practitioner stands in warm water, gently moving and massaging the client), and a Spa session., Methods: In this randomized cross-over clinical trial, all 24 adult participants with cnLBP will undergo the three interventions in balanced order with a washout-period of at least two weeks in between. Assessments will take place at baseline and follow-up of study and immediately before and after each intervention. Assessments cover the primary outcome self-reported current pain (Visual Analog Scale, range: 0-100 mm), other self-report questionnaires (addressing, e.g., personality traits or -states), and physiological parameters (e.g., measurement of spinal range of motion)., Discussion: The study adds estimates of intervention-specific effect-sizes of widespread passive aquatic interventions to cnLBP. The study also points to potential underlying pain-reducing mechanisms., Trial Registration: The protocol was approved by the Ethics Committee of the Canton Bern (ProjectID: 2018-00461). Trial registration is intended at ClinicalTrials.gov., (© 2022 The Authors.)

Temperature has a profound effect on many aspects of murine physiology. This raises the question of the best temperature at which mice should be housed to maximize the translational potential to humans. The temperatures at which mice have been routinely kept for studies of molecular physiology (20-21 °C) maximize the comfort of animal handling staff. There is a widespread movement suggesting we should perform experiments instead on mice housed at 30 °C. This often produces very different outcomes. Here we analyze the basis of this suggestion and show that while 20-21 °C is too cold, 30 °C is probably too hot. Rather we suggest an intermediate temperature "the Goldilocks solution" of 25-26 °C is probably optimal. This should be combined with providing animals with nesting material so that they can construct nests to generate microclimates that are within their own control. Providing copious nesting material has additional spin-off advantages in terms of increasing environmental enrichment. Ultimately, however, advocating a single temperature to mimic human physiology is plagued by the problem that humans vary widely in the temperature environments they experience, with consequences for human disease. Hence studying responses at a range of temperatures may provide the greatest insights and translational potential., (© 2022. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)

Simple Summary: Thermal stress is a critical issue for poultry during the summertime. It is imperative to overcome this problem by controlling the environment inside poultry houses or by water additives. This experiment evaluated the effects of two supplements for broilers in water. Nano-emulsified vegetable oil or betaine was used in two groups of broilers. One group was kept under a thermo-neutral temperature (24 °C) while the other was kept under a high temperature (35 °C). The high temperature lasted from 21 to 35 days old. The high-temperature group consumed less feed and suffered significantly from lower daily gain. Moreover, the thermo-neutral group had good meat attributes when compared to the high-temperature group. The two supplements improved the ability of broilers to use feed more efficiently and convert it to body gain compared to the un-supplemented birds. In addition, betaine enhanced carcass characteristics such as breast temperature and pH compared to the control. In summary, the heat challenge caused significant disadvantageous impacts on growth efficiency and meat qualities, while the two supplements used herein improved the performance. Therefore, it is recommended to use these supplements in the case of high temperatures inside broiler houses. The effects of nano-emulsified vegetable oil (NEVO) and betaine (BET) supplements on growth performance and meat qualities of broilers reared under cyclic heat stress (HS) were investigated. Two hundred and eighty-eight mixed-sex broilers at 21 d were randomly distributed to a 2 × 3 factorial arrangement of treatments formed by two environmental temperatures (thermoneutral (TN; 24 ± 1 °C) and cyclic high-temperature (HT; 35 ± 1 °C)) and three dietary treatments (control (CON), NEVO, and BET). The cumulative performance (21–35 d) revealed a reduction in average daily gain (ADG) (p < 0.05) in the CON compared to NEVO. NEVO and BET groups had a better feed conversion ratio (FCR) and performance efficiency factor (PEF) compared with the CON (p < 0.001, p < 0.01, respectively). The environmental temperature affected daily feed intake (DFI), ADG, FCR, and PEF. The addition of BET improved breast fillets yield, temperature, pH15min, and pH24hr (p < 0.05) in comparison with the CON. Moreover, the TN group had lower fillet temperature and higher pH15min compared to the HT. Moreover, HT increased shear force (SF), hardness, springiness, cohesiveness, and chewiness of the fillets compared to TN. In conclusion, dietary supplementation with BET and NEVO could effectively improve performance parameters and meat characteristics under HS conditions. [ABSTRACT FROM AUTHOR]