Thermoregulatory System Research Articles

Development of an experimental unit and methodology for ground-based experimental testing of two-phase thermoregulation systems for spacecrafts

Development of an experimental unit and methodology for ground-based experimental testing of two-phase thermoregulation systems for spacecrafts

Research on spacecraft environment control and astronaut health evaluation based on Modelica

Abstract The environmental control system of a manned spacecraft plays a pivotal role in maintaining the internal environment and temperature control, and it constitutes a fundamental component of the spacecraft. In this study, a Modelica-based model for the environmental control and health assessment of astronauts was examined with the objective of analysing the impact of the internal environment of the spacecraft on human physiological changes. The model employs multi-domain simulation techniques, integrating thermodynamic and hydrodynamic models to describe airflow and temperature changes, while incorporating human physiology models to capture the body’s response to these environmental changes. In particular, thermodynamic models are employed to calculate the transfer and distribution of heat within the cabin air, while hydrodynamic models are utilised to simulate airflow and pressure changes, which subsequently influence the breathing patterns and thermoregulatory mechanisms of the astronauts. The human physiology models include simulations of the cardiovascular, respiratory, and thermoregulatory systems. The coupling of these models enables the accurate prediction of the physiological state of astronauts under various environmental conditions. By modifying the environmental control parameters within the model, including air flow rate, temperature set point, and humidity level, the impact of disparate environmental control strategies can be evaluated. This method has the potential to be employed in the prediction of the health status of astronauts during various flight phases.

Integrating artificial intelligence for optimal thermal comfort: A design approach for electric heating textiles aligned with user preferences

Human thermal comfort, crucial for well-being and productivity, is often improved by personal comfort systems that offer tailored control over environmental conditions while promoting energy efficiency. Previous studies have explored various textile technologies in thermoregulation systems according to user preferences. However, limited research has focused on temperature prediction by artificial intelligence to maximize thermal comfort for varied users. This study proposes a design approach to optimize thermal comfort in electric heating textiles using artificial intelligence, considering user preferences related to age and gender differences. A fuzzy logic model is established as a proof of concept for temperature regulation by varying ambient temperature, followed by developing an artificial neural network model to predict the optimal temperature for maximum comfort. Subsequently, a smart electric heating jacket is fabricated to assess preferred heating temperatures among 50 subjects with varying ages and genders. Results from the artificial neural network model show promising temperature prediction, while subject tests reveal significant differences in skin temperatures based on gender. This emphasizes the need for artificial intelligence-based heating e-textiles to accommodate diverse user needs. The study’s findings are expected to contribute to intelligent temperature regulation in thermal textiles and wearables, benefitting both the industry and consumers through customized heating products.

Physiological Responses of Wheelchair Basketball Athletes to a Combined Aerobic and Anaerobic Training Program

Among the multifarious adapted sports, wheelchair basketball stands out as a highly recommended group activity among individuals with paraplegia, including those with Spinal Cord Injury (SCI). Athletes facing this particular impairment exhibit distinct alterations in their metabolic, cardiorespiratory, neuromuscular, and thermoregulatory systems, ultimately leading to a diminished physiological respiratory capacity in comparison to able-bodied individuals or those with other forms of impairments. The primary objective of the present research endeavor is therefore to explore the impact of a comprehensive exercise regime, encompassing both aerobic and anaerobic components, upon the enhancement of the aerobic capacity of wheelchair basketball athletes. A total of 32 wheelchair basketball players, ranging in age from 34 to 42, were enlisted in the study, with half allocated to an experimental group engaging in combined aerobic and anaerobic training [EG, n = 16], while the remaining participants were assigned to a control group undertaking solely aerobic exercise training [CG, n = 16]. The 12-minute wheelchair propulsion distance was utilized to evaluate the V̇O2peak in individuals with paraplegia, both before and after the intervention. The findings revealed a significant Time x Group interaction for the 12-minute wheelchair propulsion distance variable, highlighting a notable enhancement in the treatment group (p < 0.001). In contrast, no substantial changes were detected in the control group. Thus, the outcomes suggest that the integration of aerobic and anaerobic exercise yields a highly positive impact on the aerobic performance of wheelchair basketball players. Key words: physiology; exercise; sport; spinal cord injuries; cardiorespiratory fitness.

Adaptive integumentary features of beef cattle raised on afforested or non-shaded tropical pastures

We aimed to analyze the seasonal acclimatization process of Nelore and Canchim cattle raised on two production systems (non-shaded, NS, and integrated crop-livestock-forest, ICLF), based on the dynamics of the morphological and functional attributes of the hair coat and skin during winter and summer. The study was conducted in Brazil, in a low-altitude tropical climate region. A completely randomized 2 × 2 factorial design was adopted as follows: two production systems (NS and ICLF), two breeds (Nelore and Canchim) in a longitudinal structure, with measurements repeated over time through two stations (winter and summer). The experimental animals consisted of 32 Nelore (Bos indicus) and 32 Canchim (5/8 Bos taurus × 3/8 Bos indicus) bulls. The animals were equally distributed between two intensive rotational grazing systems. In both breeds, the hair coat was significantly thicker in winter but longer in summer, which increased epidermal protection. The Nelore bulls had shorter, wider, and thicker hairs, which are attributes that promote heat loss via conduction. The Canchim bulls showed significantly lower hair density and higher epithelium distance to sweat glands, which resulted in higher core temperature and respiratory rate. In turn, Nelore bulls had higher serum concentrations of triiodothyronine and lower serum concentrations of cortisol. However, Canchim bulls more frequently and intensely activated their thermoregulatory system and markedly adjusted their hair coat and hair features to reduce heat gain, especially in summer. Therefore, the anatomical plasticity and functional integumentary characteristics of Nelore and Canchim bulls reflect their acclimatization to tropical conditions.

Greater severity of depressive symptoms is associated with changes to perceived sweating, preferred ambient temperature, and warmth-seeking behavior

ABSTRACT The thermosensory system is relevant to both the conceptualization and treatment of depression. There is evidence that depression is associated with changes in thermoregulatory functioning, and that thermosensory pathways can be recruited to influence affect and reduce depressive symptoms. In this study, we investigated the relationship between severity of depressive symptoms and changes to measures of subjective experiences associated with thermoregulatory processes as well as the relationship between severity of depressive symptoms and affective responses to warm stimuli, specifically frequency of warmth-seeking behavior. Participants (N = 529) completed measures of depressive symptoms, subjective experiences associated with thermoregulatory processes (i.e., perceived sweating and preferred ambient temperature) and frequency of warmth-seeking behavior (e.g., long hot baths, saunas, etc.). We demonstrate that, controlling for age and gender, greater severity of depressive symptoms is associated with greater perceived sweating and lower preferred ambient temperature. Furthermore, we demonstrate that greater severity of depressive symptoms is associated with more frequent warmth-seeking behavior, and that something other than thermal preference (i.e., stated preference for warmer temperature) is driving this behavior. These data highlight the importance of incorporating the thermoregulatory system in our conceptualization of the pathophysiology of depression and support the potential to recruit thermosensory pathways to target depressive symptoms.

Pengaruh Blanket Warmer Terhadap Suhu Tubuh Pasien Intra Sectio Caesarea Sebagai Upaya Pencegahan Terjadinya Hipotermi

Sectio caesarean is a surgical process involving an incision that is very risky and causes many complications for the human body. One of the complications caused by an intra-cesarean section is hypothermia. Hypothermia is a medical emergency that occurs when the body loses heat faster than it produces warmth. When the body temperature drops, the nervous system and other organs typically cannot function properly, which in turn affects the functioning of many other organs (Dafiani, 2021). This study aimed to determine the effect of a blanket warmer on the body temperature of intra-cesarean section patients to prevent hypothermia. This quantitative study used a quasi-experimental design (pre-test–post-test with a control group design). Data were collected on intra-section cesarean patients. As many as 35 respondents had been given non-pharmacotherapy therapy in the form of a blanket warmer. The results of the analysis showed that most pregnant women were aged 20–35 years in the no-risk group (91.4%), cesarean section with absolute indication (68.6%), and cesarean section duration < 60 minutes (57.1%). The minimum body temperature of 35.7°C before receiving a blanket warmer, and a maximum body temperature of 36.6°C after receiving one. After carrying out statistical tests using the Wilcoxon test, a P-value of 0.000, or ≤ 0.05, was obtained. In conclusion, blanket warmers influence the incidence of intra-cesarean hypothermia at SMC Telogorejo Hospital. Suggestions for further research include developing variables that can disrupt the thermoregulation system, as well as comparing the use of tools other than blanket warmers to prevent hypothermia before surgery.

Investigating the transient conditions of “Sabat” space and its influence on pedestrian sensations during thermal walks. Algiers’ Casbah case study

Cities are already witnessing the impacts of climate change. Prolonged heat exposure have a direct effect on pedestrians’ thermoregulatory system, causing serious heat-related issues in the form of fatigue and thermal exhaustion. While the human body is capable of maintaining heat balance, excessive heat exposure combined with increasing heat loads can deteriorate the thermoregulatory process which leads to discomfort. Walkability is one of the significant challenges for climate change mitigation. Balancing the dichotomy of walking to mitigate climate change, and mitigating climate change to walk emphasizes the importance of promoting resilient walkability. In this context, the term “resilience” is used to highlight the need to design urban spaces able to adapt to increased urban heat, enabling pedestrians to tolerate and recover from discomfort conditions. This study investigates the potential of the “Sabat”, a traditional semi-outdoor space with lift-up design, and its distribution in generating transient thermal aeraulic conditions, and reducing fatigue sensation, hence, supporting a positive walking experience. Thermal walks have been conducted in Casbah of Algiers during temperate and hot weather conditions, in the context of uphill walking. Results revealed the alliesthesial effect of cool-shaded and ventilated Sabats to reduce fatigue sensation, which was confirmed by the significant correlation at lag-(-1) (r = 0.504, p < 0.001). Findings shed light on the importance of maintaining dynamic alliesthesia to create modulated restorative opportunities and offer starting point for hypothesizing broader trends for future implementation of Sabat design in modern cities.

Effects of Wearing Personal Protective Equipment on Serum Cortisol Levels and Physiological Variables in Healthcare Workers: A Randomised Controlled Trial in a Simulated Pandemic Environment.

The COVID-19 pandemic has necessitated the widespread use of personal protective equipment (PPE), particularly in high-risk environments. Full-body PPE is favoured for its comprehensive protection against the virus but poses challenges to the body's thermoregulatory system as it inhibits air exchange. This randomised trial was undertaken to investigate the effects of wearing a commonly used gown-type full-body PPE kit in a simulated environment. Initially, 65 healthy males were recruited and randomly divided into two groups: a study group wearing a full-body PPE kit (gown-type, full-body PPE kit with trousers, a gown-type shirt with a hood, a shoe cover, an N95 face mask, and an optional face shield) and a control group without PPE. They remained seated for three hours while wearing the PPE kit. Room conditions mimicked non-air-conditioned hospital scenarios, with temperature and humidity recorded and ventilation provided through open doors and windows, along with ceiling fan cooling. Activities with minimal physical exertion were allowed, and access to the toilet was kept to a minimum. Subjects underwent assessments of heart rate, respiratory rate, temperature, blood pressure, heart rate variability (HRV), and blood samples for serum cortisol before donning the PPE kit and entering a simulated ICU/WARD environment and after doffing. A total of 60 participants completed the study (30 in each group). Compared to the controls, serum cortisol levels significantly increased in the PPE groups, and HRV data indicated increased sympathetic activity in the PPE group. Wearing a full-body PPE kit (gown-type upper garment with trousers) was found to have a significant impact on cortisol levels and physiological variables in a simulated environment. This suggests that in situations like the COVID-19 pandemic that warrant the use of such PPE kits, appropriate measures should be taken to provide better thermal stability for maintaining the well-being of healthcare workers.

Care of The Older Fighter: Position Statement of the Association of Ringside Physicians

ABSTRACT Older Fighters are defined as combat sports athletes older than 35 years, based on heightened medical risks and historical classification. Age-related changes to the neurological, cardiopulmonary, endocrinological, thermoregulatory, osmoregulatory, and musculoskeletal systems increase these athletes’ risks for injury and may prolong their recovery. These age-related risks warrant special considerations for competition, licensure, prefight medical clearance, in-fight supervision, post-fight examination, and counseling regarding training practices and retirement from combat sports. Neurological considerations include increased risk of intracranial lesions, intracranial hemorrhage, and sequelae from traumatic brain injury (TBI), warranting more comprehensive neurological evaluation and neuroimaging. Increased risk of myocardial ischemia and infarction warrant careful assessment of cardiac risk factors and scrutiny of cardiovascular fitness. Older fighters may take longer time to recover from musculoskeletal injury; post-injury clearance should be individualized.

Sports-Related Gastrointestinal Disorders: From the Microbiota to the Possible Role of Nutraceuticals, a Narrative Analysis.

Intense physical exercise can be related to a significant incidence of gastrointestinal symptoms, with a prevalence documented in the literature above 80%, especially for more intense forms such as running. This is in an initial phase due to the distancing of the flow of blood from the digestive system to the skeletal muscle and thermoregulatory systems, and secondarily to sympathetic nervous activation and hormonal response with alteration of intestinal motility, transit, and nutrient absorption capacity. The sum of these effects results in a localized inflammatory process with disruption of the intestinal microbiota and, in the long term, systemic inflammation. The most frequent early symptoms include abdominal cramps, flatulence, the urge to defecate, rectal bleeding, diarrhea, nausea, vomiting, regurgitation, chest pain, heartburn, and belching. Promoting the stability of the microbiota can contribute to the maintenance of correct intestinal permeability and functionality, with better control of these symptoms. The literature documents various acute and chronic alterations of the microbiota following the practice of different types of activities. Several nutraceuticals can have functional effects on the control of inflammatory dynamics and the stability of the microbiota, exerting both nutraceutical and prebiotic effects. In particular, curcumin, green tea catechins, boswellia, berberine, and cranberry PACs can show functional characteristics in the management of these situations. This narrative review will describe its application potential.

Thermal adaptability of neonatal piglets: Early life welfare crisis

Thermal adaptability of neonatal piglets: Early life welfare crisis

Peristaltic mechanism of Ellis fluid with viscous dissipation and thermal radiation induced by cilia wave

Bioheat transfer analysis in tissue has attracted the attention of numerous researchers due to its widespread potential applications in the medical field, mainly in thermotherapy and the human thermoregulation system. Also, temperature regulation of the human body primarily occurs through bioheat transfer. Due to the widespread biomedical applications of bio-heat transfer, we aim to investigate the movement of biofluid and bioheat in human organs with the influences of thermal radiation and ciliary waves. The mathematical model for Ellis fluid flow through a tube includes the metachronal wave of cilia motion and convective conditions. The governing equations are created based on mass, momentum conservation, and energy. The current problem is displayed and exact solutions are managed under long wavelength [Formula: see text] and low Reynolds number [Formula: see text] approximations. An analytical approach is employed to derive expressions for longitudinal velocity, temperature, pressure gradient, and stream function as a function of the parameters of the problem. The physical behavior of the peristaltic motion of the Ellis fluid is explained in detail and illustrated graphically for various parameter values. The results of the current study provide potential information for advancement in the biomedical industry, particularly in the development of biomedical devices and processes.

Hot, cold, or just right? An infrared biometric sensor to improve occupant comfort and reduce overcooling in buildings via closed-loop control

To improve occupant comfort and save energy in buildings, we have developed a closed-loop air conditioning (AC) sensor-controller that predicts occupant thermal sensation from the thermographic measurement of skin temperature distribution, then uses this information to reduce overcooling (cooling-energy overuse that discomforts occupants) by regulating AC output. Taking measures to protect privacy, it combines thermal-infrared (TIR) and color (visible spectrum) cameras with machine vision to measure the skin-surface temperature profile. Since the human thermoregulation system uses skin blood flow to maintain thermoneutrality, the distribution of skin temperature can be used to predict warm, neutral, and cool thermal states. We conducted a series of human-subject thermal-sensation trials in cold-to-hot environments, measuring skin temperatures and recording thermal sensation votes. We then trained random-forest classification machine-learning models (classifiers) to estimate thermal sensation from skin temperatures or skin-temperature differences. The estimated thermal sensation was input to a proportional integral (PI) control algorithm for the AC, targeting a sensation level between neutral and warm. Our sensor-controller includes a sensor assembly, server software, and client software. The server software orients the cameras and transmits images to the client software, which in turn assesses occupant skin temperature distribution, estimates occupant thermal sensation, and controls AC operation. A demonstration conducted in a conference room in an office building near Houston, TX showed that our system reduced overcooling, decreasing AC load by 42% when the room was occupied while improving occupant comfort (fraction of “comfortable” votes) by 15 percentage points.

THERMOREGULATION SYSTEM FOR BIOSENSORS BASED ON FIELD-EFFECT TRANSISTORS WITH A NANOWIRE CHANNEL

In this work we present an automatic thermoregulation system for biosensors based on field-effect transistors with a nanowire channel, which provides full control on the required temperature regime in bioanalytical analises. The system elements, including field-effect transistors with a nanowire channel, temperature sensors and heaters, were fabricated on a single silicon cristal using electron beam lithography, reactive ion etching and high-vacuum deposition techniques. Unicue electronics have been developed to control and maintain temperature. The dependence of thermometer readout on heating power was measured, which is in good agreement with the results of numerical simulation. A demonstration of a thermoregulation system with PID-feedback was carried out, ensuring the establishment of a desiered temperature in the range of 30-70◦ C in 18 s in liquid. A demonstration of a thermoregulation system for detecting nucleic acids was carried out using synthetic single-stranded DNA, which is a gene fragment from the bacterium Escherichia coli. The minimal detectable response was observed for a sample with a concentration of 3 fM.

Application of Kangaroo Mother Care (KMC) Method to Maintain Body Temperature Stability of Low Birth Weight (LBW) Babies at Toto Kabila Gorontalo Hospital

Background: LBW infants are infants born with a weight of less than 2500 grams. Due to their larger surface area-to-body weight ratio, they are highly susceptible to thermoregulation system disturbances, such as hypothermia. One non-pharmacological intervention to maintain body temperature in infants is the Kangaroo Mother Care (KMC) method, as it helps stabilize heart rate and respiration and reduces the risk of infections in infants. Aim: To describe the results of applying the KMC method to LBW infants at RSUD Toto Kabila Regional Public Hospital. Method: The study design used is a descriptive case study involving three participants. The data will be presented using tables and described to illustrate the results and describe the application of the KMC method on LBW infants. Result: All three respondents experienced different increases in body temperature after applying the KMC method. The highest temperature increase was 1.9°C, while the lowest temperature increase was 1°C. Conclusion: The application of the KMC method was able to maintain normal body temperature stability, as demonstrated by the pre- and post-measurement results of body temperature after three days of applying the method on three LBW infants at RSUD Toto Kabila Regional Public Hospital.Keywords: LBW Kangaroo Mother Care, Body Temperature Stability

A Comparison of Three Anesthetic Drug Combinations for Use in Inducing Surgical Anesthesia in Female Guinea Pigs (Cavia porcellus).

Guinea pigs are often used in translational research, but providing them with safe and effective anesthesia is a challenge. Common methods like inhalant anesthesia and injectable ketamine/xylazine induce surgical anesthesia but can negatively affect cardiovascular, respiratory, and thermoregulatory systems and complicate the interpretation of research outcomes. Several alternative anesthetic regimens have been investigated, but none have consistently achieved a surgical plane of anesthesia. Therefore, identifying an anesthetic regimen that achieves a stable state of the surgical plane of anesthesia while preserving cardiorespiratory function would be a valuable contribution. To address this issue, we compared the efficacy of 3 anesthetic combinations in female Dunkin-Hartley guinea pigs: 1) alfaxalone, dexmedetomidine, and fentanyl (ADF); 2) alfaxalone, midazolam, and fentanyl (AMF); and 3) alfaxalone, midazolam, fentanyl, and isoflurane (AMFIso). We monitored anesthetic depth, heart rate, oxygenation, respiratory rate, respiratory effort, blood pressure, and body temperature every 15 min from injection to recovery. We also recorded the time to loss of righting reflex, duration of anesthesia, and time to achieve a surgical plane. The results showed no statistically significant differences in induction and recovery times among the groups. In the AMFIso group, 100% of the animals achieved a surgical plane of anesthesia, whereas only 10% of the animals in the AMF group reached that level. None of the animals in ADF group reached a surgical plane of anesthesia. Respiratory rate was significantly lower in the AMFIso as compared with the ADF group (P < 0.001) but was not different between the AMF and ADF groups. Temperature was significantly lower in the AMFIso group as compared with both the ADF and AMF groups (P < 0.001). In conclusion, both combinations of solely injectable anesthetics assessed in this study can be used for short, nonpainful procedures without significant cardiorespiratory depression. However, for mildly to moderately painful surgical procedures, the addition of an inhalant anesthetic like isoflurane is necessary for female guinea pigs.

Abstract TMP111: Selective Activation of Peritoneal TRPV1-Containing Vagal Afferents Promotes Sustained Mild Hypothermia and Neuroprotection Following Stroke

Intro: Mild hypothermia has been clinically effective at improving outcomes in cardiac arrest patients for decades. Similarly, mild hypothermia has been shown to neuroprotective in experimental stroke models. Unfortunately, hypothermia protocols in awake subjects are hampered by inconsistent temperature management due to incomplete suppression of cold defense mechanisms (e.g. shiver response). To address a need for better strategies for cooling conscious subjects, we sought to promote mild hypothermia by pharmacological activation of heat-sensing nerve fibers in the thermoregulatory system. We hypothesize that selective activation of TRPV1-containing vagal afferents in the peritoneal cavity can promote sustained hypothermia and protection following stroke. Methods: Aged (18-20 mo) and young (11 weeks) C57BL6 mice of both sexes were given a capsinoid mixture consisting of capsiate and dihydrocapsiate. Mice from both the aged and young cohorts underwent permanent distal middle cerebral artery occlusion (pdMCAO) or sham before recovering for 2hrs in warming cages to maintain normal body temperatures during post-stroke recovery. At 2 hours after stroke, mice were given capsinoids or vehicle (4 IP injections, 90 min interval) to produce 6 hours of mild hypothermia (or normothermic control). After 3 days brains were collected for histological analysis. Results: Capsinoids are particularly suited for region selective activation of TRPV1 targets, as they are degraded by ubiquitous esterases, and thus limited in biodistribution to distant targets. This regionally restricted activation was demonstrated through induction of mild hypothermia with IP capsinoid administration, but not with oral or subcutaneous delivery. We demonstrated that the hypothermic effect is TRPV1 dependent and that IP capsinoid delivery increases activity of the cervical vagus (hook electrode). We applied this capsinoid-mediated hypothermia approach to the pdMCAO model and demonstrated a significant reduction of brain infarct at 3 days post-stroke in both young and aged mice of both sexes. Conclusion: Selective activation of TRPV1-containing peritoneal vagal afferents is sufficient to promote sustained mild hypothermia and protection following ischemic stroke.

Thermoregulation System for Biosensors Based on Field-Effect Transistors with a Nanowire Channel

Thermoregulation System for Biosensors Based on Field-Effect Transistors with a Nanowire Channel

Evaluation of a thermoregulatory intravascular catheter in critically ill burns patients.

Patients with severe burns are at high risk of thermoregulatory failure. Yet, there is a lack of consensus regarding the optimum approach to temperature dysregulation in patients with severe burns. Intravascular temperature management catheters may offer a superior method of temperature control, but robust data are lacking. In this article, we describe our experience in using a thermoregulatory catheter for temperature management in a tertiary referral burns center. We conducted a single-center, prospective evaluation of the use of a thermoregulatory intravenous catheter system (Thermogard XP®) in critically injured burns patients admitted to our intensive care unit over an 18-month period. Ten patients had a total of 12 catheters inserted. Patient temperatures were maintained between a median low of 36.9 °C and a median high of 38.4 °C while in the intensive care unit. If patients were transferred to theater, the median temperature change was -0.15 °C (interquartile range [IQR] -0.3, 0) if TBSA was ≤50% and -1.45 °C (IQR -2.05, -0.975) if >50%. No surgical procedures were terminated due to intraoperative hypothermia. On return from theater, 72.2% of patients were normothermic with a median temperature of 36.8 °C. Thirty percent of patients developed a thrombotic complication. Overall, the device appeared reliable in achieving and maintaining normothermia for critically ill burns patients manifesting temperature dysregulation. It may also be of benefit to patients expected to show temperature fluctuations during operative procedures. Further research is needed to define whether this represents an improvement over current practice and investigate the thrombus risk associated with such devices.