Browsing by Author "Cho, Elizabeth"
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Item Assessment of Digit Skin Temperatures Via Infrared Thermography Under Different Climatic Conditions(2024-05) Boettger, Chloe E.; Maddux, Scott D.; Cho, Elizabeth; Romero, Steven A.The responsiveness of the manual/pedal digits (i.e., finger/toes) to temperature changes makes them valuable indicators of thermoregulatory function. Further, while infrared thermography is used in many medical settings, its utility in assessing acute changes in digit skin temperatures remains poorly established. Accordingly, this research investigated the use of forward-looking infrared (FLIR) imaging as a methodological tool for analyzing digital skin temperatures across varying climatic conditions. A Teledyne FLIR E76 camera and associated FLIR Studio software were used to assess peripheral digit skin temperatures in a sample of 10 living human subjects (3 female, 7 male). Images of each hand and foot were captured every 5 minutes over a 45-minute period during exposure to four controlled climatic conditions in an environmental chamber. These experimental conditions included a control (22°C and 50% humidity), hot-humid (37°C and 85% humidity), hot-dry (44°C and 15% humidity), and cold-dry (5°C and 80% humidity) exposures. All images were taken at a perpendicular angle from the skin surface at a distance of 0.45 mm, as measured using the camera's laser-guided range finder function. Baseline images were similarly taken during a preliminary rest period prior to each experimental exposure. This resulted in a total of 2,200 images collected from the left hand and left foot of the 25 participants. Following theoretical expectations, preliminary findings indicate peripheral digit temperatures predictably decrease during the cold-dry exposure, while the hot-dry and hot-humid exposures induce increases in digit temperatures. These preliminary results suggest that infrared thermography likely provides an expedient mechanism for accurately assessing peripheral skin temperatures in humans under different climatic conditions. Infrared thermography may thus have valuable applications for assessing thermoregulatory function in both clinical and research settings.Item Assessment of digit skin temperatures via infrared thermography under different climatic conditions.(2024-03-21) Boettger, Chloe; Tran, Baonhu; Ward, Lyndee; Counts, Caroline; Cowgill, Libby; Ocobock, Cara; Cho, Elizabeth; Maddux, ScottThe responsiveness of the manual/pedal digits (i.e., finger/toes) to temperature changes makes them valuable indicators of thermoregulatory function. Further, while infrared thermography is used in many medical settings, its utility in assessing acute changes in digit skin temperatures remains poorly established. Accordingly, this research investigated the use of forward-looking infrared (FLIR) imaging as a methodological tool for analyzing digital skin temperatures across varying climatic conditions. A Teledyne FLIR E76 camera and associated FLIR Studio software were used to assess peripheral digit skin temperatures in a sample of 25 living human subjects (12 female, 13 male). Images of each hand and foot were captured every 5 minutes over a 45-minute period during exposure to four controlled climatic conditions in an environmental chamber. These experimental conditions included a control (22°C and 50% humidity), hot-humid (37°C and 85% humidity), hot-dry (44°C and 15% humidity), and cold-dry (5°C and 80% humidity) exposures. All images were taken at a perpendicular angle from the skin surface at a distance of 0.45 mm, as measured using the camera’s laser-guided range finder function. Baseline images were similarly taken during a preliminary rest period prior to each experimental exposure. This resulted in a total of 2,200 images collected from the left hand and left foot of the 25 participants. Following theoretical expectations, preliminary findings indicate peripheral digit temperatures predictably decrease during the cold-dry exposure, while the hot-dry and hot-humid exposures induce increases in digit temperatures. These preliminary results suggest that infrared thermography likely provides an expedient mechanism for accurately assessing peripheral skin temperatures in humans under different climatic conditions. Infrared thermography may thus have valuable applications for assessing thermoregulatory function in both clinical and research settings.Item Evaluating philtrum-to-tragus distance as an external predictor of nasal passage dimensions: A computed tomography (CT) approach(2024-03-21) Counts, Caroline; Boettger, Chloe; Tran, Baonhu; Ward, Lyndee; Cowgill, Libby; Ocobock, Cara; Cho, Elizabeth; Maddux, ScottAccurate quantification of nasopharyngeal temperature requires the placement of a flexible intranasal probe into the upper or mid-nasopharynx. Yet, without guidance from medical imaging, data shows that in practice less than half of nasopharyngeal temperature probes are optimally positioned. Still, previous studies have suggested that the distance between the philtrum (external nose) to tragus (external ear) provides a reliable predictor of internal nasal passage dimensions. However, previous attempts to verify the accuracy of this external proxy have returned equivocal results. Accordingly, this study employed measurements collected from CT scans of 11 living participants (4 female, 7 male) to assess associations between external philtrum-tragus length and internal lengths of the nasal cavity, nasopharynx, and total nasal passage (i.e., cavity + pharynx). Results show statistically significant correlations between philtrum-tragus length and internal measurements of nasal cavity (r=0.412, p=0.033) and total nasal passage (r=0.502, p=0.015) length. In contrast, no significant correlation was identified between philtrum-tragus length and nasopharynx length (r=0.110, p=0.320). Despite the small size of the study sample, these suggest that philtrum-tragus length can provide insights for estimating internal dimensions relating to the location of the end of nasal cavity (i.e., choanal aperture) and the posterior wall of nasopharynx. Thus, this external measurement may enhance the accuracy of intranasal probe placement, especially when medical imaging data (i.e., radiographs, CT, MRI) are not available for guidance. Accordingly, additional investigation into the applied utility of philtrum-tragus length with larger sample sizes appears warranted.Item Every breath you take: Experimentally investigating respiratory responses to hot environments(2024-03-21) Tran, Baonhu; Ward, Lyndee; Boettger, Chloe; Counts, Caroline; Cowgill, Libby; Ocobock, Cara; Cho, Elizabeth; Maddux, ScottThe human body loses heat to the environment through two mechanisms: the skin and the respiratory system. Accordingly, it has previously been hypothesized that respiration may play an important role in overall thermoregulatory responses to heat stress. However, previous studies investigating respiratory responses to heat have generally failed to account for variation in humidity levels seen across hot environments (i.e., hot-humid vs. hot-dry conditions). Thus, the goal of this study was to experimentally test for potential differences in respiratory responses to heat stress given variation in air humidity. A mixed-sex sample of human volunteers (5 females, 6 males) were subjected to three different climatic conditions: room temperature (22°C, 50% relative humidity (RH)), hot-dry (44°C, 15% RH), and hot-humid (37°C, 85% RH).Test subjects were exposed to each climatic condition for 45 minutes, with metabolic and respiratory data collected for 30 minutes using a wearable COSMED K-5 metabolic system. Respiratory frequency (Rf, breaths/minute) and oxygen consumption (VO2, ml/minute)were assessed. Results of a repeated-measures ANOVA found a statistically significant difference in Rf values between the climatic conditions (F=5.05, p=0.017). Subsequent Tukey-Kramer multiple-comparison post-hoc test results indicate that participants exhibited significantly higher Rf values in the hot-dry condition (mean=17.498) compared to the room temperature (mean=15.859)and hot-humid (mean=15.764) conditions. In contrast, no significant differences for VO2 consumption between the three climatic conditions (F=2.33, p=0.123) were found. These results indicate that in the hot-dry climatic condition, participants breathe more frequently without increasing the total amount of air inspired (i.e., taking more frequent but shallower breaths). These results are largely consistent with findings of previous studies that have demonstrated similar physiological responses to heat stress. Furthermore, our study highlights the existence of differential respiratory responses in hot-dry vs. hot-humid conditions, suggesting that humidity may play an important role in mediating respiratory responses to heat stress. Additional research into the impacts of humidity on respiratory function is thus warranted.Item Investigating Associations Between Asthma and Nasal Abnormalities: A Computed Tomography (CT) Approach(2023) McCullough, Jason "Drew"; Maddux, Scott D.; Cho, Elizabeth; Ward, LyndeePurpose: Asthma affects over 300 million people worldwide and 3,500 people suffer asthma related deaths each year. Although there is no clear cause of asthma, approximately 90% of asthmatics suffer from cold/exercise induced bronchoconstriction, a symptom triggered by the inhalation of cold and/or dry air. As the nasal passages account for most of the heat and moisture transferred to inspired air during respiration, anatomical variation in nasal morphology may contribute to asthma development. While the existence of nasal anatomical variants is well documented, little is known about the prevalence of such variants among asthmatics. Methods: Accordingly, this study sought to investigate potential associations between asthma and three common nasal anatomical variants: septal deviations, concha bullosa, and paradoxical turbinate. This study analyzed Computer Topography (CT) scans of a diverse, mixed sex sample (n=242) from the New Mexico Decedent Image Database (NMDID). The asthmatic individuals (n= 120) were identified through associated medical records and compared to a control sample of non-asthmatics (n = 122). CT scans were analyzed using Avizo permitting qualitative coding of each anatomical variant for presence and type. Chi-square tests of independence were then used to test for differences in variant prevalence between the asthmatic and control samples. Results: The results of our study show significantly higher prevalence of concha bullosa in asthmatics compared to control individuals (χ2= 5.87, p=0.015), with 70.0% asthmatics exhibiting at least one pneumatized turbinate compared to only 54.9% of control individuals. Conclusions: This result suggests a potential relationship between the presence of conchae bullosa and asthma, possibly due to this variant negatively influencing intranasal air-conditioning capabilities. Future work employing computational fluid dynamics (CFD) analyses may be able to further elucidate the influence concha bullosa have on nasal passage air flow and conditioning. Such work could provide important insights into the role nasal anatomy may play in asthma prevalence and severity. This project was supported by Texas Center for Health Disparities grants RF00241 & RI40241Item The influence of humidity and precipitation on skeletal morphological variation in East Asia(2022) Cho, Elizabeth; Cowgill, Libby; Blomquist, GregoryHuman ecogeographic proportions in Europe, Africa, and the Americas are well studied, but Asia remains underrepresented despite its diverse range of climates, latitudinal expanse, and long history of habitation. The monsoon is a significant environmental force across East Asia with two distinct phases: a summer phase and winter phase. The southwest winds of the summer component cross the equator bringing heavy rain during the warmer, humid months of the year while the winter's northeastern winds bring cold, dry air down from Siberia during the year's coldest months. Previous assessment of East Asian body form and minimum temperature during the monsoon's winter phase has found body size to conform with Bergmann's rule while limb length patterns did not follow Allen's rule. These analyses found that Southeast Asian are small overall, possibly due to the greater selective pressure of living in a humid climate which is exacerbated by the monsoon's heavy rain summer component. Reduction of body size in these populations could allow for better thermoregulation as the climate conditions of Southeast Asia are not conducive to heat dissipation via sweat evaporation. For this study, measurements throughout the body were gathered on female (N=439) and male (N=460) individuals from seven East Asian countries and represent 10 populations. Osteometric data and proportional indices were combined with appropriately matched autosomal SNP data, precipitation, and humidity data using linear mixed model analysis to evaluate the selective pressure of these climatic factors specifically associated with the summer phase of the monsoon. The influence of both climate variables was found to vary depending on the region of the body assessed. This further supports the need for ecogeographic research to assess the body as a whole and highlights the complexity of climatic adaptation.