Thermoregulatory Ability Research Articles

The Thermoregulatory and Thermal Responses of Individuals With a Spinal Cord Injury During Exercise, Acclimation and by Using Cooling Strategies–A Systematic Review

Background: In individuals with a spinal cord injury thermoregulatory mechanisms are fully or partially interrupted. This could lead to exercise-induced hyperthermia in temperate conditions which can be even more distinct in hot conditions. Hyperthermia has been suggested to impair physiological mechanisms in athletes, which could negatively influence physical performance and subjective well-being or cause mild to severe health issues.Objective: The aim was to evaluate the literature on the thermoregulatory and thermal responses of individuals with a spinal cord injury during exercise in temperate and hot conditions taking the effects of cooling techniques and heat acclimation into account.Data sources: Two electronic databases, PubMed and Web of Science were searched. Studies were eligible if they observed the influence of exercise on various thermoregulatory parameters (e.g., core and skin temperature, sweat rate, thermal sensation) in individuals with a spinal cord injury.Results: In total 32 articles were included of which 26 were of strong, 3 of moderate and 3 of weak quality. Individuals with a high lesion level, especially those with a tetraplegia, reached a higher core and skin temperature with a lower sweat rate. The use of cooling techniques before and during exercise can positively affect the burden of the impaired thermoregulatory system in all individuals with a spinal cord injury.Conclusion: Due to the absence of normal thermoregulatory abilities, individuals with a high-level spinal cord injury need special attention when they are exercising in temperate and hot conditions to prevent them from potential heat related issues. The use of cooling techniques can reduce this risk.

Smart composite nanofiber mats with thermal management functionality

Nanofibers with thermal management ability are attracting great attention in both academia and industry due to the increasing interest in energy storage applications, thermal insulation, and thermal comfort. While electrospinning is basically a fiber formation technique, which uses electrostatic forces to draw ultrafine fibers from a wide variety of polymers, with the addition of phase change materials (PCMs) to the electrospinning solution it enables the production of shape stabilized phase change materials with thermal management functionality. In this study, polyacrylonitrile (PAN) nanofibers containing paraffinic PCMs were produced by electrospinning method and the composite nanofibers obtained were characterized in terms of their morphology, chemical structure, thermal properties, stability, thermal degradation behaviour and hydrophobicity. Besides, PCMs with different phase transition temperatures were added simultaneously into the nanofiber structure in order to investigate the tunability of the thermoregulation properties of the nanofibers. Uniform nanofibers with thermal management functionality were obtained. It could be possible to obtain composite nanofibers showing thermoregulation ability over a wider temperature range by simultaneous addition of PCMs with different melting points into the nanofiber structure. 50 wt% PCM could be added to PAN nanofiber structure wherein the resulting nanofiber exhibited 58.74 J g−1 of enthalpy storage during heating and 57.41 J g−1 of heat release during cooling. The composite nanofibers maintained their cylindrical fiber morphology, structure and composition after multiple heating–cooling cycles and retained their thermal management functionality. The contact angle measurements showed that the addition of PCMs imparted hydrophobicity to the nanofibers.

Thermoregulation in post-cardiac arrest patients treated with targeted temperature management

ObjectiveEvaluate the relationship between heat generation during rewarming in post-cardiac arrest patients receiving targeted temperature management (TTM) as a surrogate of thermoregulatory ability and clinical outcomes. MethodsThis is a prospective observational single-centre study conducted at an urban tertiary-care hospital. We included post-cardiac arrest adults who received TTM via surface cooling device between April 2018 and June 2019. ResultsPatient heat generation was calculated by multiplying the inverse of the average machine water temperature with time to rewarm to 37 °C and standardized in two ways to account for target temperature variation: (1) divided by number of degrees between target temperature and 37 °C, and (2) limited to when patient was rewarmed from 36 °C to 37 °C. The primary outcome was poor neurologic status, defined as Cerebral Performance Category (CPC) score 3–5, and the secondary outcome was 30-day survival. Sixty-six patients were included: 45 (68%) had a CPC-score of 3–5 and 23 (35%) were alive at 30 days. Besides initial rhythm and arrest downtime, baseline characteristics were similar between outcomes. Heat generation was not associated with poor neurological outcome (CPC 3–5: 6.6 [IQR: 6.1, 7.4] versus CPC 1–2: 6.6 [IQR: 5.7, 7.6], p = 0.89) or survival at 30 days (non-survivors: 6.6 [IQR: 6.6, 7.4] vs. survivors: 6.6 [IQR: 5.7, 8.0, p = 0.78]). ConclusionHeat generation during rewarming was not associated with neurologic outcomes. However, there was a relationship between poor neurological outcome and higher median water temperatures. Time to rewarm was prolonged in patients with poor neurological outcome.

Thermoregulation at birth differs between piglets from two genetic lines divergent for residual feed intake

Thermoregulation is essential to piglets' neonatal survival. This study used infrared thermography (IRT) to assess thermoregulation abilities of piglets from two lines divergent for residual feed intake (RFI). At birth, morphology (weight, length, width and circumference), vigour (respiration, mobility and vocalisation), and rectal temperature were recorded from piglets of the 11th generation of the low RFI (LRFI, more efficient; n = 34) and the high RFI (HRFI, less efficient; n = 28) lines. Infrared thermography images were taken at 8, 15, 30 and 60 min post partum. Temperatures of the ear base and tip, and of the back (i.e. shoulders to rumps) were extracted (Thermacam Researcher Pro 2.0) and analysed with linear mixed models (SAS 9.4). Piglets had different average hourly weight gain (HRFI = 7.1 ± 1.3 g/h, LRFI = 3.6 ± 1.3 g/h; P < 0,001) but did not differ in morphology or vigour. All temperatures increased overtime. At birth, piglets' rectal temperature was correlated with the initial temperature of the ear base and the maximum back temperature (0.37 and 0.33, respectively; P < 0.05). High residual feed intake piglets had lower ear tip temperatures than LRFI piglets at 15 (24.7 ± 0.37 °C vs. 26.3 ± 0.36 °C, respectively; F1, 63.5 = 9.11, P < 0.005) and 30 min post partum (26.2 ± 0.47 °C vs. 27.6 ± 0.44 °C, respectively; F1, 66.9 = 4.52, P < 0.05). Moreover, thermal pattern of the ear tip differed between the two genetic lines. In conclusion, IRT allowed non-invasive assessment of piglets' thermoregulation abilities and indicated an influence of genetic selection for RFI on neonatal thermoregulation abilities.

137 Randel Lecture: Genetic control of thermotolerance in cattle at the whole-animal and cellular level

Abstract Research by Randel and others has revealed the extensive genetic diversity in thermotolerance existing in cattle. Genetic differences in resistance to heat stress involve genes that affect body temperature regulation and that stabilize cellular function during hyperthermia. There are large differences between breeds in ability to regulate body temperature during heat stress. There is also genetic variation in thermoregulatory ability within breeds that arose in cold climates – the estimate of heritability of rectal temperature during heat stress in Holsteins is 0.17. Efforts are underway to identify genes conferring increased thermoregulatory ability in thermotolerant breeds and transfer these to thermosensitive breeds. One such gene is the prolactin receptor gene (PRLR). Several mutations in PRLR exist in criollo-type B. taurus that result in formation of a truncated receptor protein. Cattle with this mutation, which is dominant, have a short sleek hair coat and are referred to as “slick”. The slick mutation has been introduced into Holsteins by crossbreeding with Senepol cattle and in Red Angus by gene editing. Slick Holsteins are less affected by heat stress than wild-type Holsteins with respect to rectal temperature, milk yield and reproduction. Genetic variation also exists in cellular responses to elevated temperature (i.e., heat shock). Exposure of preimplantation embryos to heat shock, for example, causes a greater reduction in subsequent development of Angus, Holstein, Angus x Holstein or Jersey embryos than embryos from Brahman or Nelore (B. indicus) or Romosinuano (criollo). One gene with alleles affecting cellular resistance is the heat shock protein 70 gene HSPA1A. A mutation in the promoter region of HSPA1Ais associated with increased transcription of the encoded protein and enhanced survival of lymphocytes exposed to heat shock. Identification of other genes conferring thermotolerance will result in the increased ability to produce thermotolerant lines of cattle via genetic selection or gene transfer.

Use of infrared thermography to noninvasively assess neonatal piglet temperature.

Hypothermia is risk factor for piglet neonatal mortality, especially for low birth weight piglets. Piglets with intrauterine growth retardation (IUGR) also have a higher mortality risk at birth. This study aimed to validate infrared thermography (IRT) as an alternative to rectal temperature (RT) to measure piglet temperature in the hour postpartum, and to identify piglets with thermoregulation difficulties. At birth (6.3 ± 0.35 min postpartum), 67 piglets were dried, weighed, scored for growth retardation (IUGR; 0–3), and isolated in a plastic box where IRT images were taken, followed by RT. Piglets were then returned to the farrowing pen, and the process repeated at 15, 30, and 60 min postpartum. Piglets were ranked according to their weight (quartiles: 0.57–1.27 kg, 1.27–1.5 kg, 1.5–1.74 kg, 1.74–2.44 kg). Temperatures (ear base and tip; minimum, maximum and average of back) were extracted from IRT images (Thermacam Researcher Pro 2.0). Pearson correlations between temperature measures were calculated, and the effect of time, IUGR score, and weight were included in linear mixed models (SAS 9.4). RT was correlated with all IRT data across time points (P < 0.05); correlations were strongest with the ear base, and weakest with the ear tip and minimum back temperature. Both IUGR score and weight rank affected ear base (P < 0.05) and RTs (P < 0.05). The lightest piglets, and piglets with severe IUGR had the lowest temperature, relative to their counterparts. Indeed, differences between all weights categories were significant for RT. Piglets with the lowest weight (0.27–1.27 kg) had lower ear base temperatures than piglets in the third quartile (1.5–1.74 kg; 35.2 ± 0.36 °C vs. 36.5 ± 0.35 °C, t64.9 = −4.51, P < 0.001) and the heaviest piglets (1.74–2.44 kg; 35.2 ± 0.36 °C vs. 36.4 ± 0.36 °C, t70.4 = −3.97, P < 0.005). Overall, piglets with severe IUGR (score 3) had a lower RT than normal piglets (score 0; 35.8 ± 0.46 °C vs. 37.2 ± 0.42 °C, t43.1 = 3.16, P < 0.05) and piglets with mild IUGR (score 1; 35.8 ± 0.46 °C vs. 37.1 ± 0.40 °C, t45.3 = 2.92, P < 0.05); and they also had lower temperature at the base of the ear than normal piglets (35.1 ± 0.42 °C vs. 36.3 ± 0.36 °C, t63.1 = 3.01, P < 0.05). These results confirmed that IRT is an interesting noninvasive tool for assessing neonatal piglets’ thermoregulatory abilities and could be used in research investigating successful interventions for piglets at risk of hypothermia.

Hot and bothered: The role of behaviour and microclimates in buffering species from rising temperatures.

In Focus: Bladon, A. J., Lewis, M., Bladon, E. K., Buckton, S. J., Corbett, S., Ewing, S. R., … Turner, E. C. (2020). How butterflies keep their cool: Physical and ecological traits influence thermoregulatory ability and population trends. Journal of Animal Ecology. https://doi.org/10.1111/1365-2656.13319 Threatened with rising average temperatures and the new normal of climate extremes, species that cannot keep pace with climate change must adapt where they are, or face extinction. The ranges of many British butterflies have indeed extended northwards as the climate has warmed, but this option is increasingly restricted by the expansion and intensification of urban and agricultural lands. On a day-to-day basis, butterflies can thermoregulate using behaviours such as adjusting their wing positioning or moving into suitable microclimates. The extent to which these two options buffer individuals from free-air temperature, however, is not well known. Nor is the extent to which the different mechanisms are exploited by different species, and whether that has had any bearing on species' population trends over the time-scale of recent climate change. Using a simple and easily replicated approach, Bladon etal.(2020) were able to quantify intra- and interspecific variation in buffering ability, and species' relative reliance on the two thermoregulatory mechanisms of wing adjustment versus microclimate selection. The authors report marked variation in buffering capacity, correlated with wing size, wing colouration and taxonomic family. Species also differed in their thermoregulatory behaviours, with some - such as the Ringlet Aphantopus hyperantus and Large Skipper Ochlodes sylvanus-achieving impressive buffering through wing positioning. Others, like the Brown Argus Aricia agestis and Small Heath Coenonympha pamphilus, were more reliant on microclimate selection, and these were the species most likely to have shown declining population trends over the past 40years. The study underscores the importance of individual thermoregulatory behaviours for understanding species' vulnerability to climate change. In combination with much improved methods for measuring and modelling climate at biologically relevant scales, the approach of Bladon etal.(2020) can and should be extended to identify the places and species most at risk, and the steps that conservation practitioners can take to maximise resilience to climate change. Much attention has been given to improving habitat connectivity to facilitate range shifts, but we should also consider how microclimate availability can be enhanced to allow species to manage when they cannot move.

How butterflies keep their cool: Physical and ecological traits influence thermoregulatory ability and population trends.

Understanding which factors influence the ability of individuals to respond to changing temperatures is fundamental to species conservation under climate change. We investigated how a community of butterflies responded to fine-scale changes in air temperature, and whether species-specific responses were predicted by ecological or morphological traits. Using data collected across a UK reserve network, we investigated the ability of 29 butterfly species to buffer thoracic temperature against changes in air temperature. First, we tested whether differences were attributable to taxonomic family, morphology or habitat association. We then investigated the relative importance of two buffering mechanisms: behavioural thermoregulation versus fine-scale microclimate selection. Finally, we tested whether species' responses to changing temperatures predicted their population trends from a UK-wide dataset. We found significant interspecific variation in buffering ability, which varied between families and increased with wing length. We also found interspecific differences in the relative importance of the two buffering mechanisms, with species relying on microclimate selection suffering larger population declines over the last 40years than those that could alter their temperature behaviourally. Our results highlight the importance of understanding how different species respond to fine-scale temperature variation, and the value of taking microclimate into account in conservation management to ensure favourable conditions are maintained for temperature-sensitive species.

Morphometric analysis of dung beetle (Gymnopleurus mopsus: Scarabaeidae: Coleoptera) populations from two different biomes in Mongolia

AbstractStudying the phenotypic variation of organisms along environmental gradients can provide insight into the influences of specific environmental factors. Mongolia, which is distributed across three different biomes, is an ideal location for studying the mechanisms that underlie such phenotypic variation over a large range of climate. The present study examined the variation in shape and size of the body in a ball-rolling dung beetle, Gymnopleurus mopsus (Pallas), in Mongolia and investigated the effects of climate on the species’ morphology. A total of 290 individuals were collected from seven sites and were analysed using multivariate and regression approaches, as well as geometric morphometrics. Body shape and size varied across the study sites and between the different biomes. Populations from the desert-steppe region had thinner bodies and longer heads than those from the steppe region, possibly to facilitate burrowing. Variation in the species’ body size followed a pattern that was the converse of Bergmann’s rule and, thus, might increase heat capacity and enhance thermoregulation ability in the desert-steppe region. Accordingly, the results of the present study provide novel insight into the influence of climate on the variation of dung beetle phenotypes.

Transparent Wood Composites Fabricated by Impregnation of Epoxy Resin and W-Doped VO2 Nanoparticles for Application in Energy-Saving Windows.

Two types of transparent wood composites with anisotropic structure for energy-saving windows were successfully fabricated by infiltration of epoxy resin dispersion containing tungsten-doped vanadium dioxide nanoparticles (W-doped VO2 NPs) into the delignified wood template and subsequent polymerization. The well integration of the epoxy resin, W-doped VO2 NPs, and the pore-structured wood endowed the anisotropic composites with high visible transmittance (68.2% for the composite prepared from longitudinally cut trees (L-composite), 73.3% for the composite prepared from radically cut trees (R-composite)), obviously different mechanical performance (fracture stress of 74.57 MPa (L-composite) and 56.14 MPa (R-composite) and modulus of 1.47 GPa (L-composite) and 1.23 GPa (R-composite)), and low thermal conductivity (0.20 W·m-1 K-1 (L-composite) and 0.32 W·m-1 K-1 (R-composite)). Moreover, these two kinds of W/VO2 transparent wood composites both show an outstanding thermoregulation ability when they are used as windows. A significant amount of heat (from a simulated light source) was reflected by VO2 NPs, and as a result, the indoor temperature of a demo system had a significant slower temperature increase rate when compared with that for a similar system with a common glass panel applied. Novel transparent wood composites combining a low thermal conductivity wood template and thermochromic VO2 NPs provide a potential solution for replacement of heavy, high thermal conductivity, and infrared transparent glass but still meet indoor occupancy view perception.

Evaluation of pumice for development of low-cost and energy-efficient composite phase change materials and lab-scale thermoregulation performances of its cementitious plasters

Integration of a building mass with a phase change-energy storage material is able to improve its thermal efficiency. With this respect, pumice was evaluated as low-cost supporting material for development of energy-efficient composites containing capric acid (CA) and polyethylene glycol(PEG) as phase change material (PCM). The developed leak-proof composites was also incorporated separately with ordinary cement (OC; Portland Cement) to produce novel plaster with thermal energy storage (TES) ability for thermoregulation of buildings. The DSC analysis results demonstrated that the shape-stabilized composite PCMs (S-SCPCMs) had melting temperatures of 31.03 °C and 8.80 °C and TES capacity of 116.27 J/g and 98.39 J/g, respectively. Cycling thermal degradation stability and TES dependability of the leak proof composites were examined by TGA techniques. The lab-scale test revealed that the indoor center temperatures (ICT) of the cubic chambers plastered separately by pumice/CA/OC and pumice/PEG/OC mortars were maintained at comfortable temperature range for relatively longer times compared to the control chamber plastered by OC mortar.

Effect of mound size on intranest thermoregulation in the red wood antsFormicarufa and F. polyctena (Hymenoptera, Formicidae)

Red wood ants are capable of active thermoregulation in the nest, which allows them to achieve a high number of workers and a dominant position in biocenoses. We investigated the features of the spring warm-up and the ability for active thermoregulation of the mounds of the ants Formica polyctena and F. rufa in the vicinity of Kyiv, Ukraine. We have proposed a model of thermoregulation of the mound, which takes into account the heat flow from the sun, heat exchange with air and soil, and endogenous heat generated by the antcolony. The calculation of the model for specific values showed that only F. polyctena mounds with a diameter of more than 0.9 m and F. rufa mounds with a diameter of more than 1.1 m are able to maintain a constant optimum temperature in the nest. Comparison of the calculated data with the measurement results onthe studied nests showed that the diameters of the majority of moundsexceededthe critical values for both speciesindicatingthe ability ofthermoregulation.The possibility of using the model to study the thermoregulation of moundsin different natural areas is discussed. Keywords:

Evidence of trans-generational developmental modifications induced by simulated heat waves in an arthropod

Heat waves are considered to pose a greater risk to arthropods with their limited thermoregulation abilities than the increase of mean temperatures. Theoretically, within- and trans-generational modifications may allow populations to keep pace with rapidly occurring heat waves. Here, we evaluated this assumption using individuals of predatory mite Amblydromalus limonicus from the F1 and F2 generation, which were exposed to summer or simulated heat wave conditions during juvenile development. Independent of generation, survival and male body size were insensitive to heat waves. Heat stress elongated juvenile development of F1 males and females, and lowered the F1 female size at maturity indicating non-adaptive within-generational effects. Trans-generational modifications speeded up the development of F2 males and females and resulted in larger body size of F2 females deriving from the heat wave-experienced F1 generation. Faster F2 development should be adaptive, because it reduces the exposure time to heat waves and promotes an early beginning of mating activities. Being large at extreme high temperatures maybe a benefit for the F2 females, because large individuals are less vulnerable to dehydration and overheating. Thus, the potential fitness loss from reduced F1 growth should be compensated by increased fitness in the F2 indicating adaptive trans-generational modifications.

Effects of Deepwater Horizon oil on feather structure and thermoregulation in gulls: Does rehabilitation work?

Impacts of large-scale oil spills on avian species are far-reaching. While media attention often focuses on lethal impacts, sub-lethal effects and the impacts of rehabilitation receive less attention. The objective of our study was to characterize effects of moderate external oiling and subsequent rehabilitation on feather structure and thermoregulation in gulls. We captured 30 wild ring-billed gulls (Larus delawarensis) and randomly assigned each individual to an experimental group: 1) controls, 2) rehabilitated birds (externally oiled, rehabilitated by washing), or 3) oiled birds (externally oiled, not rehabilitated). We externally oiled birds with weathered MC252 Deepwater Horizon oil (water for controls) and collected feathers and thermography imagery (FLIR) approximately weekly for four weeks to investigate feather structure (quantified using a barbule clumping index) and thermoregulatory ability (characterized by internal body temperature and external surface temperature). Post-oiling feather clumping was significantly higher in oiled and rehabilitated birds compared to controls, but steadily declined over time in both groups. However, feather microstructure in rehabilitated birds was indistinguishable from controls within three weeks of washing whereas the feathers of oiled birds were still significantly clumped a month post oiling. Internal body temperatures didn't differ in any of the groups, suggesting birds maintain thermoregulatory homeostasis in spite of moderate external oiling. External temperatures for rehabilitated birds didn't differ from controls within a week of rehabilitation. Overall, rehabilitation procedures were effective and washed birds were in better condition compared to non-rehabilitated, oiled birds. This study provides evidence that the benefits of rehabilitation for moderately oiled birds likely outweigh the costs with regard to feather structure and thermoregulation. While feather preening and time were insufficient to reestablish baseline fine scale feather structure in moderately oiled birds, the significant clumping reduction over time may indicate that rehabilitation of lightly oiled birds may not be necessary and deserves further study.

PSXI-37 Differences in thermoregulation ability and genetic parameters of skin traits in Angus, Brahman and their Crossbreds

Abstract Thermoregulation is important for beef cattle but tends to be negatively correlated with production traits. The objective of this study was to determine the variation in core body temperature and to estimate genetic parameters of skin traits in Angus, Brahman, and different levels of crossbred heifers (n = 337) reared in hot and humid conditions. Core body temperature was recorded as vaginal temperature every 15 minutes for 5 consecutive days. Dry bulb temperature and relative humidity in the pasture were also measured every 15 min and used to calculate a temperature-humidity index (THI). Five mm skin biopsies were collected from the right side of sixth thoracic bone of each heifer. Cross-sections of biopsy samples with a thickness of 7 µm were stained with Hematoxilin–Eosin technique. The number and area of sweat and sebaceous glands, and the thickness of dermis and epidermis were determined using the ImageJ program. Data were analysed using PROC MIXED in SAS 9.4 with a model including the effect of breed, year, and their interaction. Genetic parameters were estimated using WOMBAT. Average core body temperature of Angus, 25%, 37.5%, 50%,75% and 100% Brahman were 39.50±0.05, 39.30±0.04, 39.15±0.05, 39.2±0.0, 39.03±0.05, 39.04±0.05, respectively. Brahman heifers had lower core body temperature compared to Angus heifers (P = 0.0006). Heifers with smaller and more numerous sweat glands had higher (P &amp;lt; 0.01) and more variable core body temperature (P &amp;lt; 0.0001). Heritability of core body temperature under high and low THI was 0.44±0.006 and 0.61±0.003, respectively. Dermis and epidermis thickness had the lowest heritability (0.231±0.002) and the highest heritability (0.75±0.007), respectively. Heritabilities for the number of sweat glands and total sweat gland area were 0.375±0.02 and 0.432±0.006, respectively. In conclusion, thermoregulation was highly correlated with breed composition, number of sweat glands and the average size of sweat glands.

The role of temperature as a driver of metabolic flexibility in the Red-billed Leiothrix (Leiothrix lutea)

BackgroundThe thermoregulatory ability of animals is strongly influenced by the temperature of their environment. Acclimation to cold requires a range of physiological and morphological adjustments. In this study, we tested the hypothesis that a small passerine, the Red-billed Leiothrix (Leiothrix lutea), can maintain homeothermy in cold conditions by adjusting the physiology and biochemistry of its tissue and organs and return to its former physiological and biochemical state when moved to a warm temperature.MethodsPhenotypic variation in thermogenic activity of the Red-billed Leiothrixs (Leiothrix lutea) was investigated under warm (35 °C), normal (25 °C) or cold (15 °C) ambient temperature conditions. Oxygen consumption was measured using an open-circuit respirometry system. Mitochondrial state-4 respiration and cytochrome-c oxidase (COX) activity in liver, kidney heart and pectoral muscle were measured with a Clark electrode.ResultsBirds acclimated to an ambient temperature of 15 °C for 4 weeks significantly increased their basal metabolic rate (BMR) compared to a control group kept at 25 °C. Birds acclimated to 35 °C decreased their BMR, gross energy intake (GEI) and digestible energy intake (DEI). Furthermore, birds acclimated to 15 °C increased state-4 respiration in their pectoral muscles and cytochrome-c oxidase (COX) activity in their liver and pectoral muscle, compared to the 25 °C control group. Birds acclimated to 35 °C also displayed lower state-4 respiration and COX activity in the liver, heart and pectoral muscles, compared to those kept at 25 °C. There was a positive correlation between BMR and state-4 respiration, and between BMR and COX activity, in all of the above organs except the liver and heart.ConclusionsOur study illustrates that the morphological, physiological, and enzymatic changes are associated with temperature acclimation in the Red-billed Leiothrix, and supports the notion that the primary means by which small birds meet the energetic challenges of cold conditions is through metabolic adjustments.

Abstract 158: Association Between Initial Body Temperature and Neurologic Outcomes of Out-Of-Hospital Cardiac Arrest Undergoing Targeted Temperature Management

Objectives: Targeted temperature management (TTM) is the core post-resuscitation care to minimize neurologic deficit after out-of-hospital cardiac arrest (OHCA). Uncontrolled body temperature of patients may reflect the thermoregulation ability which can be associated with neurologic damage during arrest. The aim of this study was to investigate the association between initial body temperature (BT) and neurologic outcomes in OHCA patients who underwent TTM. Methods: We used nationwide OHCA database from January 2016 to December 2017. Adult OHCA patients with presumed cardiac etiology who underwent TTM after return-of-spontaneous circulation (ROSC) were included. The main exposure was a BT at initiation of TTM which was categorized into 3 groups: low (-35.5°c), middle(35.6°c-37.4°c), and high BT (37.5°c-). The primary outcome was good neurologic outcome (cerebral performance categories (CPC) 1 or 2). Adjusted ratios (AORs) and 95% confidence intervals (CIs) were estimated to evaluate association between initial BT of TTM and outcome in multivariable logistic regression model. Stratified subgroup analyses were according to the target temperature of TTM (hypothermia vs normothermia). Results: Of a total of 744 patients, 208 (28.0%) patients were low initial BT group and 471 (63.3%) patients were normal initial BT group and 65 (8.7%) patients were high initial BT group. Good neurological recovery rate was 13.9% in low initial BT group, 41.8% in middle initial BT group and 36.9% in high initial BT group. The adjusted odds ratios for good neurologic recovery were 0.281 (95% confidence interval [CI] 0.17-0.47) in low BT group and 0.65 (95% CI 0.34-1.27) in high BT group compared with normal initial BT group. Similar results were also found regardless of target temperature of TTM. Conclusion: Low initial BT of TTM was associated with unfavorable neurologic recovery for OHCA patients who underwent TTM after ROSC.

Effect of shearing on some physiological and hormonal parameters in Akkaraman sheep.

ObjectiveShearing is one of the practices that is applied periodically to fiber producing animals, which can also alter resistance of animals to high temperatures in especially summer months. This study aimed to investigate effects of shearing on some physiological and hormonal parameters in Akkaraman sheep during summer season.MethodsThis study was carried out on 39 non-pregnant Akkaraman ewes (aged 1.5 years at the beginning of experiment). The 39 ewes were chosen randomly from the flock belonging to the Erciyes University and they were assigned to two groups as follows: i) group A (n = 20) designed as the control group, they were shorn and group B (n = 19) designed as the experimental group, they were unshorn. Prior to the shearing (−1 day) and on days 1, 7, 15, 30, 45, 60, 75, and 90 following the shearing, blood samples were taken from the vena jugularis of each sheep. Cortisol, β-endorphin, growth hormone (GH), thyroxine (T4), triiodothyronine (T3), and heat shock protein 70 (HSP-70) concentrations were determined using the enzyme immunoassay method. Body weight (BW), rectal temperature (RT), pulse rate (PR), and respiratory rate (RR) of each sheep were recorded at the same time. The data obtained were analyzed using two-way repeated measures analysis of variance.ResultsStatistical analysis showed a significant effect of shearing×period interaction (p< 0.01) and a significant effect of period (p<0.01) on BW, HSP-70, cortisol, T4 and RT, PR, GH, β-endorphin, T3, respectively. Also these analysis showed no significant effect of shearing× period interaction or period on RR.ConclusionThe results showed that the thermoregulation abilities of sheep were affected by shearing treatment and the shorn ewes were less affected by heat stress. In conclusion, based on the data of this study, shearing can be considered as a necessary management practice that requires protection for sheep from the effect of heat stress.

The Embryos of Turtles Can Influence Their Own Sexual Destinies

Sessile organisms with thermally sensitive developmental trajectories are at high risk from climate change. For example, oviparous reptiles with temperature-dependent sex determination (TSD) may experience strong (potentially disastrous) shifts in offspring sex ratio if reproducing females are unable to predict incubation conditions at the time of oviposition. How then have TSD reptile taxa persisted over previous periods of extreme climatic conditions? An ability of embryos to move within the egg to select optimal thermal regimes could buffer ambient extremes, but the feasibility of behavioral thermoregulation by embryos has come under strong challenge. To test this idea, we measured thermal gradients within eggs in semi-natural nests of a freshwater turtle species with TSD, manipulated embryonic thermoregulatory ability, and modeled the effects of embryonic thermoregulation on offspring sex ratios. Behavioral thermoregulation by embryos accelerated development and influenced offspring sex ratio, expanding the range of ambient conditions under which nests produce equal numbers of male and female offspring. Model projections suggest that sex ratio shifts induced by global warming will be buffered by the ability of embryos to influence their sexual destiny via behavioral thermoregulation.

Thermal comfort of people from two types of air-conditioned buildings - Evidences from chamber experiments

Air conditioning has been basically generalized in buildings as the most effective means of cooling in South China; there are two common types of air conditioning: centralized air conditioning system and split-type air-conditioner. The present study recruited 60 healthy young people, half from buildings with centralized air conditioning system (CAC buildings) and half from buildings with split-type air-conditioner (SAC buildings), and exposed them to a wide range of temperatures (20–32 °C) and humidity (50% and 70%) in a climate chamber. The results showed that the mean skin temperature was significantly higher for subjects from the CAC buildings under the non-neutral conditions, whereas there were no significant differences for other physiological responses. The two groups of subjects reported the same neutral temperatures (26.8 °C and 26.6 °C) and thermal sensitivities (0.31 °C-1). The 90% thermally acceptable SET ranges were 24.8–27.4 °C and 24.4–30.1 °C for the two groups of subjects, and the range was narrower by 3.1 °C and the upper limit was lower by 2.7 °C for subjects from the CAC buildings. Thermal history containing intermittent and short-term high & low-temperature exposures in the SAC buildings is suggested to strengthen the occupants' thermoregulatory ability. The long-term experience with a more stable cool environment and the less perceived controls are expected to shape a higher thermal expectation of occupants in the CAC buildings. This study specifies the thermal requirements of people in the two types of air-conditioned buildings, and promotes the understanding of the impacts of thermal history and expectation on human thermal comfort.