Stress Measurements Research Articles

Better emotion regulation mediates gratitude and increased stress in undergraduate students across a university semester.

It is well established that university students are vulnerable to poor mental health. Although increased gratitude has been shown to reduce stress among students, a clearer understanding of key mechanisms underpinning this relationship are needed to better inform theoretical models and potential interventions targeted at improving well-being in university students. The present study provides the first direct test of whether capacity for emotion regulation mediates the relationship of gratitude with stress at the beginning and middle of the academic semester. This study is also the first to assess this relationship in a cross-lagged panel mediation model. We used a repeated measures design and a total of 343 undergraduate students completed two online surveys with validated measures of gratitude, stress, and emotion regulation-one at the beginning and the second in the middle of the academic semester. Results showed that emotion regulation mediated the relationship between gratitude and stress at the beginning of semester, and again 6weeks later. A Clogg's z-score test suggested that the strength of the indirect effect significantly increased across the two time points. A post-hoc cross-lagged panel model found that high gratitude at the beginning of the semester predicted low stress in the middle of the semester via emotion regulation. These data provide novel evidence that emotion regulation may serve as a key protective factor against undergraduate stress. The results provide evidence to support leading theories on how gratitude can reduce stress and promote well-being in university students. They also highlight the practical importance of strengthening emotion regulation abilities in university students and can be used to inform future targeted interventions to improve well-being in university students.

Hydrogels in biosensing and medical diagnostics

This article presents an in-depth examination of recent advancements in medical and biotechnological sensing technologies, focusing on the forefront of innovation in hydrogel-based sensors within the domains of biomedical engineering and regenerative medicine. It delves into cutting-edge sensing technologies that facilitate non-invasive glucose monitoring, highlights progress in the development of intelligent solutions for wound care, and discusses the application of optical and fluorescence-based sensors for real-time diagnostics within the body. Further, it reviews the latest glucose monitoring devices, alongside wearable and implantable sensors designed for the continuous monitoring of health, including the measurement of physiological strain and stress. The exploration extends to the latest in non-invasive and minimally invasive technologies for ongoing health assessment, and to imaging and visualization techniques critical for medical diagnostics and therapeutic procedures. These advancements mark a pivotal move toward more efficient, precise, and patient-focused healthcare technologies, signaling new avenues for diagnosis, monitoring, and treatment in the healthcare sector.

Ferulago Angulata methanolic extract ameliorates scopolamine-induced memory impairment through the inhibition of hippocampal monoamine oxidase activity.

Ferulago angulata is a medicinal herb from the Apiaceae family known for its antioxidant, anti-apoptotic, and neuroprotective properties. This study aimed to assess the effects of F. angulata extract on neurobehavioral and biochemical parameters in scopolamine-induced amnesic rats. Fifty-six male Wistar rats were divided into seven groups and orally treated with F. angulata extract (100, 200, 400mg/kg) and Rivastigmine (1.5mg/kg) for 10 days. Starting on the sixth day of treatment, the Morris water maze behavioral study was conducted to evaluate cognitive function, with scopolamine administered 30min before training. Biochemical assays, including monoamine oxidase and oxidative stress measures, were performed on hippocampal tissue. Results showed that extract treatment significantly attenuated scopolamine-induced memory impairment in a dose-dependent manner. Following scopolamine administration, malondialdehyde levels and monoamine oxidase A/B activity increased, while total thiol content and catalase activity decreased compared to the control group. Pretreatment with F. angulata extracts ameliorated the scopolamine-induced impairment in all factors. Toxicological evaluation of liver, lung, heart, and kidney tissues did not indicate any side effects at high doses. The total extract of F. angulata prevents scopolamine-induced learning and memory impairment through antioxidant mechanisms and inhibition of monoamine oxidase. These results suggest that F. angulata extract is effective in the scopolamine model and could be a promising agent for preventing dementia, especially Alzheimer's disease.

Multiple psychiatric diagnoses and return-to-work following posttraumatic stress injury rehabilitation

BACKGROUND: Posttraumatic stress injury (PTSI) is a term used to describe a range of psychiatric difficulties which arise following exposure to a psychologically traumatic event. The impact of being diagnosed with multiple psychiatric conditions on the return-to-work (RTW) outcomes of individuals with PTSI has not been adequately researched. OBJECTIVE: The current study examined whether the presence of two or more psychiatric conditions occurring simultaneously is predictive of RTW outcomes in workers with PTSI. METHOD: A population-based cohort design was conducted using archival data from injured workers admitted to a PTSI rehabilitation program. Differences in RTW outcomes and demographic, administrative, and clinical variables were compared between individuals with single and multiple psychiatric diagnoses. A range of variables were entered into a multivariable logistic regression model predicting RTW. RESULTS: The final logistic regression model indicated workers had higher odds of RTW if they had a single psychiatric diagnosis (Adjusted Odds Ratio (AOR) 2.20), non-elevated scores on a measure of traumatic stress (AOR 1.85), and reported higher self-perceived readiness to RTW (AOR 1.24). CONCLUSION: Being diagnosed with multiple psychiatric conditions appears to be associated with more negative RTW outcomes following PTSI rehabilitation.

The impact of the Systematic Assessment for Resilience (SAR) framework on students’ resilience, anxiety, depression, burnout, and academic-related stress: a quasi-experimental study

BackgroundMedical students face significant psychological stress, impacting their academic performance and well-being. The Systematic Assessment for Resilience (SAR) framework is designed to enhance resilience and mitigate stress among medical students, addressing the need for interventions within the assessment system in medical education. The aim of this study was to evaluate the implementation of SAR framework on medical students’ resilience, anxiety, depression, burnout, and academic stress.MethodsThis study employed a quasi-experimental design with pre- and post-testing. It involved the training of course coordinators in implementing the SAR framework and its integration into the daily learning activities. Fourth-year medical students were assessed before and after the intervention using standardized measures of resilience, anxiety, depression, burnout, and academic stress. Data were analyzed using quantitative methods and thematic analysis for qualitative feedback.ResultsPost-intervention, students demonstrated a significant increase in resilience scores (p < 0.001) and a notable decrease in measures of anxiety, depression, and academic stress (p < 0.001). The burnout types were also statistically different (p < 0.001) except client-related burnout (p > 0.05). Qualitative feedback of the course coordinators highlighted an improved learning environment, increased coping strategies, and a more supportive academic culture.ConclusionThe SAR framework significantly contributes to enhancing medical students’ resilience and reducing psychological distress. Its implementation suggests a promising approach to fostering a supportive educational environment that not only addresses the psychological challenges faced by medical students but also enhances their academic performance and overall well-being. Further research is warranted to explore the long-term impacts of SAR across different medical education contexts.

Flaw sensitivity of bacterial cellulose hydrogel under monotonic and cyclic loadings

The presence of flaw in solid materials can lead to stress concentration, resulting in the reduction of rupture stress and stretchability of material. When the flaw is sufficiently smaller than a material-specific length, referred to as flaw sensitivity length, the material exhibits flaw insensitivity. The flaw sensitivity length is a critical material property that reflects how the material is sensitive or insensitive to crack. However, the impact of crack length on the load-bearing process of material remains an open problem. In this work, we characterize the flaw sensitivity of a stretchable material, bacterial cellulose hydrogel, under monotonic and cyclic loadings. Through fracture and fatigue tests, we first determine that the hydrogel exhibits high fracture toughness and fatigue resistance. We next characterize the flaw sensitivity of the hydrogel through two visualized experimental methods. Photoelasticity observation on the stress distribution in samples during loading shows that the samples with cracks below 2 mm exhibit uniform stress distribution during the deformation process, while those with cracks above 2 mm experience stress concentration at crack tip. Scanning electron microscope observation on the microstructure morphology of samples under fixed stretch shows that the samples with cracks below 2 mm exhibit uniform alignment of nanofibers, while those with cracks above 2 mm exhibit more intense alignment and even bundling of nanofibers at crack tip. Similar trends are observed in the samples under cyclic loading, where the transition length is also about 2 mm. Notably, the flaw sensitivity lengths obtained by the visualized methods agree well with that obtained by direct measurement of rupture stress and theoretical estimations under monotonic and cyclic loadings. The methods offer novel way to study the flaw sensitivity of materials, thereby contributing to the exploration of failure mechanisms.

Characterization of depression subtypes and their relationships to stressor profiles among middle-aged and older adults: An analysis of the canadian longitudinal study on aging (CLSA)

The current diagnostic criteria for depression do not sufficiently reflect its heterogeneous clinical presentations. Associations between adverse childhood experiences (ACEs), allostatic load (AL), and depression subtypes have not been extensively studied. Depression subtypes were determined based on clinical presentations, and their relationships to AL biomarkers and ACEs were elucidated in a sample of middle-aged and older adults. Participants from the Canadian Longitudinal Study on Aging who screened positive for depression were included (n = 3966). Depression subtypes, AL profiles and ACE profiles were determined with latent profile analyses, and associations between them were determined using multinomial logistic regression. Four depression subtypes were identified: positive affect, melancholic, typical, and atypical. Distinct associations between depression subtypes, stressor profiles and covariates were observed. Among the subtypes compared to positive affect, atypical subtype had the most numerous significant associations, and the subtypes had unique relationships to stressor profiles. Age, sex, smoking status, chronic conditions, marital status, and physical activity were significant covariates. The present study describes distinct associations between depression subtypes and measures of stress (objective and self-reported), as well as related factors that differentiate subtypes. The findings may inform more targeted and integrated clinical management strategies for depression in individuals exposed to multiple stressors.

Associations of prenatal stress with 5-year-old children's executive function in a low socioeconomic status population.

Prenatal stress has a significant, but small, negative effect on children's executive function (EF) in middle and high socioeconomic status (SES) households. Importantly, rates and severity of prenatal stress are higher and protective factors are reduced in lower SES households, suggesting prenatal stress may be particularly detrimental for children's EF in this population. This study examined whether prenatal stress was linked to 5-year-old's EF in a predominantly low SES sample and child sex moderated this association, as males may be more vulnerable to adverse prenatal experiences. Participants were 132 mother-child dyads drawn from a prospective prenatal cohort. Mothers reported on their depression symptoms, trait anxiety, perceived stress, everyday discrimination, and sleep quality at enrollment and once each trimester, to form a composite prenatal stress measure. Children's EF was assessed at age 5 years using the parent-report Behavior Rating Inventory of Executive Function - Preschool (BRIEF-P) Global Executive Composite subscale and neuropsychological tasks completed by the children. Mixed models revealed higher prenatal stress was associated with lower BRIEF-P scores, indicating better EF, for females only. Higher prenatal stress was associated with lower performance on neuropsychological EF measures for both males and females. Results add to the limited evidence about prenatal stress effects on children's EF in low SES households.

Abstract PO2-09-07: Neighborhood Disadvantage and Social Adversity in Breast Cancer Patients

Abstract Introduction: Neighborhood disadvantage has been shown to independently predict breast cancer specific survival even after considering access to care barriers. This effect may be explained in part by biologic influences of the neighborhood environment on breast tumors. Social genomics literatures posits that this relationship is mediated by chronic stress in the form of social adversity, i.e. disadvantaged neighborhoods may be leading to increased stress for patients which in turn may effect tumor biology. Our objective in this study was to link a measure of patient-reported neighborhood specific stress with an objective and widely used measure of neighborhood disadvantage, the Area Deprivation Index (ADI). Methods: In this prospective cohort study patients with stage I-IV breast cancer completed survey questions from a validated Neighborhood Social Environment Adversity Survey (NSEAS) to measure perceived stress caused by their environment. Questions included both 5-item and 4-item Likert scale answer choices with higher scores indicating higher stress. Responses were standardized into Z-scores and composite and subscale scores were calculated by summation. Subscales included threat to safety, social cohesion, and aesthetic quality. Survey questions demonstrated good reliability with a Cronbach’s α of 0.72. Cohort addresses were used to determine the ADI, a continuous measure from 1-10 with higher scores indicating more disadvantage. Hierarchical linear regression was used to assess the relationship between ADI and NSEAS composite and subscale scores while controlling for covariates. Results: 380 breast cancer patients completed the NSEAS 61.6% were Hispanic, 17.0% were Non-Hispanic White, and 21.4% were Non-Hispanic Black. Mean age (SD) was 56 (12) years. Mean (SD) ADI was 4 (3). On univariate analysis, we found that ADI significantly predicts NSEAS composite and subscale scores (Composite β =0.63, t=5.68, p&amp;lt; 0.001; Threat to Safety β =0.18, t=5.07, p&amp;lt; 0.001; Social Cohesion β =0.19, t=3.35, p&amp;lt; 0.001; Aesthetic Quality β =0.15, t=4.20, p&amp;lt; 0.001). After controlling for age, race, ethnicity, highest education level, patient insurance, and annual household income, we found that ADI continued to significantly predict levels of NSEAS (Composite β =0.48, t=4.02, p&amp;lt; 0.001; Threat to Safety β =0.14, t=3.57, p&amp;lt; 0.001; Social Cohesion β =0.14, t=2.34, p=0.02; Aesthetic Quality β =0.12, t=3.09, p=0.002). Conclusion: In our novel study, we found that higher levels of neighborhood disadvantage independently predict higher levels of perceived neighborhood stress in breast cancer patients. Because of the known detrimental effects of both chronic stress and neighborhood disadvantage on health, understanding the specific factors of stress caused by neighborhood-level social adversity can help define targetable areas of intervention for future studies. These findings contribute to current literature on how and why neighborhood disadvantage leads to worse breast cancer outcomes. Table 1. Hierarchical Regression Illustrating Relationship between Neighborhood Disadvantage and Patient-Reported Neighborhood Social Environment Adversity Survey Scores Citation Format: Alexandra Hernandez, Maya Lubarsky, Susan Kesmodel, Michael Antoni, Neha Goel. Neighborhood Disadvantage and Social Adversity in Breast Cancer Patients [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO2-09-07.

Abstract PO3-02-03: Ketogenic diet and letrozole to inhibit PI3K signaling in ER+ breast cancer

Abstract Obesity is associated with an increased risk of breast cancer recurrence, similar in magnitude to the reduction in risk seen with the use of adjuvant chemotherapy. However, whether and how obesity causes that increased risk of recurrence remains unknown. Plausible mechanisms include obesity-mediated increases in estrogen signaling, inflammatory conditions resulting from obesity, or effects on insulin or other growth factor signaling pathways resulting from the insulin-resistant state that often accompanies obesity. While phosphatidyl inositol 3-kinase (PI3K) signaling is the normal, biological effector of insulin signaling, abnormal activation of PI3K is of particular concern in breast cancer, where it is associated with resistance to endocrine therapies and HER2-targeted therapies. We hypothesize that at least part of the adverse outcome associated with obesity results from aberrant activation of PI3K signaling in tumors. This may confer resistance to established therapies, or directly stimulate tumor growth (particularly in tumors with existing PI3K pathway mutations), or both. We tested a dietary intervention designed to alter insulin resistance pathophysiology coupled with endocrine therapy in the well-established neoadjuvant treatment paradigm in breast cancer. This will allow us to study the effects of the dietary intervention directly on tumor biology. The primary objective of this neoadjuvant study was to assess feasibility and tolerability of 2 weeks of a very low-carbohydrate ketogenic diet in combination with letrozole for patients with early stage operable ER+ disease. Up to 36 patients will be enrolled for this pilot and feasibility study (24 in the treatment group and 12 controls). Baseline metabolic parameters will be measured and the treatment group will begin a dietitian-supervised 2-week diet to induce a ketogenic state, along with letrozole 2.5 mg daily. The control group will receive only letrozole. At the end of 2 weeks, patients will proceed with surgical treatment of their breast cancer. We will report the primary outcome measure of feasibility, assessed by determining 1) the proportion of patients in the diet group achieving ketosis, 2) adherence to the diet and 3) participant-reported measures of stress, fatigue, and emotional health. For both groups, cell proliferation will be measured in a tumor biopsy obtained from the surgical specimen and compared with the pre-treatment diagnostic biopsy. Correlative studies will evaluate tumor markers of insulin/PI3K signaling before and after the intervention and between diet and control. Citation Format: Brent Rexer, Vandana Abramson, Sara Nunnery, Sonya Reid, Laura Kennedy, Melinda Sanders, Jessica Bennett, Paula Gonzalez-Ericsson, Violeta Sanchez. Ketogenic diet and letrozole to inhibit PI3K signaling in ER+ breast cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO3-02-03.

Special Issue: “Fluctuating Asymmetry as a Measure of Stress: Influence of Natural and Anthropogenic Factors”

The main cause of stress, according to Selye [...]

Stress, hardiness and eating disorder symptoms in military academy cadets

ABSTRACT Eating disorders are a persistent and debilitating problem, especially among college age men and women. This problem is exacerbated in occupations such as the military, where maintenance of strict standards regarding weight, fitness and appearance is important for job retention and promotion. Also, previous research confirms that stress is a contributing element to eating disorders. It is thus important to identify factors that may assist individuals to remain resilient and avoid stress-related health and eating difficulties. The present study utilizes historical data to examine the impact of stress on health and eating disorder symptoms in a representative sample of West Point military academy cadets, while testing the role of gender and hardiness as stress moderators in this relation. A survey containing measures of stress, hardiness and eating disorders symptoms was completed by 387 cadets in the fall and spring of 2000–2001. Moderation effects were tested with advanced conditional process analysis procedures developed recently by Hayes (2022). Results show that hardiness was a significant moderator, with cadets low in hardiness showing increased eating disorder symptoms and more general health symptoms. While gender was not a significant moderator with respect to eating disorder symptoms, it was significant for general health symptoms; female cadets showed more stress-related health symptoms than their male counterparts. These results suggest that eating disorder symptoms in military academy cadets and college students more generally may be reduced through programs aimed at developing hardiness attitudes and stress coping approaches.

Liver-specific Bmal1 deletion in mice leads to increased aortic stiffness and altered vascular remodeling

Circadian rhythms have an important role in cardiovascular physiology. Circadian clock genes are critical for vascular homeostasis. Global loss of the circadian clock gene Bmal1 increases aortic stiffness with impaired vascular function and blood pressure rhythm in mice. We previously found that hepatocyte-specific Bmal1 deletion (HBK) in the liver changes perivascular adipose tissue-mediated vascular function in young adult mice, indicating that liver circadian clock disruption distally affects function in another tissue and potential cross-talk between the liver and vasculature. We hypothesized that liver-specific Bmal1 deletion leads to aortic stiffness and pathological vascular remodeling. Studies were performed in 4- to 6- month old male HBK and flox control mice. Aortic stiffness, measured by pulse wave velocity, was significantly elevated in HBK mice compared to flox control mice (Flox: 1.84 ± 0.1 m/s; HBK: 2.9 ± 0.2 m/s; n = 5, p &lt; 0.01). Systolic blood pressure (tail-cuff) in the light phase was similar in both flox control and HBK mice (Flox: 101 ± 1 mm Hg; HBK: 103 ± 2 mm Hg; n = 3-5, p = 0.35). Aortas and plasma were collected at ZT2 for histological analysis and metabolite measurements. MetaMorph software analysis of Masson’s Trichrome-stained aortic sections revealed significantly increased aortic wall fibrosis in HBK mice (% fibrosis per area, Flox 17.0% ± 3.3%, HBK 27.4% ± 2.1%, p=0.03). The medial cell number in H&amp;E stained-aortic sections was increased in HBK mice compared to flox control mice (Flox: 534.6 ± 31.9; HBK: 1069 ± 90.1; p &lt; 0.01). TUNEL stained apoptotic cells were also counted and more apoptotic cells were observed in young HBK mice aortas compared to flox controls (Flox: 224.4 ± 56.1; HBK: 408.4 ± 20.8; p = 0.02). Aortic wall thickness was not different in young adult HBK mice compared to flox control mice. Aortic levels of the lipid peroxidation marker vascular 4-hydroxynonenal (4-HNE), a measure of oxidative stress, were similar between flox control and HBK mice. In plasma, the oxidative stress marker, 8-hydroxy-2’-deoxyguanosine (8-OHdG), a DNA damage product, and plasminogen activator inhibitor-1 (PAI-1) were not different between genotypes. In conclusion, our findings indicate that liver circadian clock disruption increases aortic stiffness and fibrosis with higher cell numbers as well as aortic apoptosis. These data suggest that altered vascular remodeling in HBK mice may contribute to aortic stiffness resulting in cardiovascular disease. Funded by P01HL136267 to JSP, R21AA026906 to SMB, and AHA 856877 to PP. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

The novel equipment for measuring internal stress in acrylic

Acrylic is widely used in aquariums, windows of planes and submarines, and even scientific experiments like the Sudbury Neutrino Observatory (SNO) and the Jiangmen Underground Neutrino Observatory (JUNO). Internal stress has a significant impact on the properties and characteristics of acrylic such as strength, fracture and creep, which is highly concerned and has become a hotspot in research field. The measurement of internal stress is an important issue, which includes two aspects - the calibration of stress-optical coefficient of acrylic and the measurement of birefringence optical path difference (BOPD) caused by internal stress. The measuring equipment mainly realize the measurement of BOPD, and currently have the largest dynamic range of 50–3000 nm. Dynamic range is considered as one of the core performance indicators of measuring equipment, and a larger dynamic range is urgently required to meet the needs of different scenarios. The novel equipment for measuring internal stress in acrylic has been designed and developed based on photo-elastic principle and spectrometric method, which has the dynamic range of 20–12000 nm and the uncertainty of stress measurement better than 3%. The measuring principle, components, functions and measurements of the novel measuring equipment are introduced and discussed in this article.

Effect of Anisotropy on Residual Stress Measurement of 316L Stainless Steel by Ultrasonic Surface Wave

Fe–Cr alloys are widely used in power, petroleum, and manufacturing industries for their good resistance to corrosion and oxidation at high temperatures. Ultrasound is the only nondestructive method so far to measure the residual stress of in-service components. However, for parts with material anisotropy, such as materials processed by rolling, the measurement accuracy is highly restrained. In this paper, a rolled 316L stainless steel sample is used to study the influence of texture on the measurement of residual stress by ultrasonic surface wave. The experimental results show that the propagation velocity of surface waves in the sample has anisotropic characteristics. The wave velocity parallel to the rolling direction (0°) is the maximum, and the wave velocity perpendicular to the rolling direction (90°) is the minimum, thereby affecting the measurement accuracy. It is found that reducing the frequency of surface waves can reduce the influence of anisotropy. Therefore, a low-frequency method and modified formula are used to improve the measurement accuracy. The maximum error in the rolling direction is reduced from 21.3 to 3.6 MPa, and the maximum relative error is also reduced from 45.4 to 9.0%. The modified formula can further reduce the influence of anisotropy, with the maximum error value further reduced to 2.3 MPa, the maximum relative error reduced to 4.9%, and the surface wave detection accuracy effectively improved.

A Prebiotic Diet Increases Cardiovascular Adaptability Under Hypergravity-Induced Stress

Life in space presents significant challenges to mammalian physiology and the longer one is in space, the greater the impact. Three major stressors are present in space: 1) changes in gravitational environment, 2) psychological/physiological stress, and 3) constant low dose radiation. It is critical, therefore, to discover interventions that promote stress resilience. Dietary prebiotics selectively increase the relative abundances of probiotic bacterial species in the gut. We have previously reported that a diet enriched in galactooligosaccharide (GOS) and polydextrose (PDX) compared to control diet robustly elevates parabacteroides distasonis, clostridium leptum, and reduces the negative impact of acute and chronic stress. Interoceptors (e.g., baroreceptors) sense gravity-induced changes in blood pressure and cardiac function/structure. There is evidence that hypergravity disrupts autonomic and cardiovascular homeostasis and function. Cardiovascular homeostasis depends on a sympathetic and parasympathetic balance reflected in heart rate variability (HRV), a measure of cardiovascular stress. The following study was designed to test the hypothesis that GOS+PDX reduces the cardiovascular impacts of living in an altered gravitational environment. Adult female mice were housed in 1G or 3G and were fed GOS+PDX or a matched control diet for 4 weeks on the NASA Ames 1.22-meter radius centrifuge. We recorded electrocardiograms (ECG) in animals from all four groups immediately before, halfway through, and immediately after centrifugation. We analyzed HRV data using a Python-based Jupyter notebook and R. R was used to perform a 1F-LD-1F ANOVA with pair-wise comparisons to quantify changes in HRV longitudinally. Classic time domain based HRV metrics, standard deviation of the successive differences between adjacent R-R intervals and standard deviation of NN intervals, showed little change over time. Instead, frequency domain measures showed results were housing in 3G compared to 1G reliably changed Shannon entropy, Sample entropy, and low to high frequency ratio at each time-point. The changes across time reflected adaptation to hypergravity and a consequent reduction in HRV. Poincare plot analysis and low to high frequency ratio metrics showed divergent compensatory reactions between diets at 3G. Overall, 3G impacted HRV less in mice that were fed the prebiotic diet compared to the control diet. Further longitudinal studies with greater temporal resolution are needed to assess changes in HRV caused by gravitational changes. However, our data suggests the prebiotic diet significantly reduces 3G activation of sympathetic drive and increases parasympathetic drive, potentially reducing cardiovascular stress in animals exposed to high gravity. NASA grant 80NSSC19K1038 funded this project. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Induction of TNFα by flavin adenine dinucleotide (FADH) protects neonatal C57Bl6 lungs from high oxygen induced lung injury

Background: Bronchopulmonary dysplasia (BPD) is a serious lung disease caused by oxidative stress, predominately affecting premature infants that require prolonged oxygen support. The co-factor flavin adenine dinucleotide (FADH) facilitates glutathione reductase (GR) enzymatic activity and increases the bioavailability of the antioxidant glutathione (GSH). As such, we hypothesized that intranasal delivery of FADH can improve redox homeostasis and attenuate lung injury following chronic high oxygen supplementation (0.85% FiO2) by altering pro-inflammatory signal transduction pathways in a C57Bl6 newborn mouse model for BPD. Methods: We used a prolonged hyperoxia-induced lung injury rodent model to recapitulate the clinical and histological changes present in BPD. Newborn mice were housed in FiO2 85% (hyperoxic) or 21% O2 (normoxic) from day of birth until post-natal day (PN) 14. FADH (7 μM) or saline (control) treatments were administered daily via intranasal insufflation on PN 14-21 in a final volume of 1.5μL/g body weight. BALF and lung tissue samples were collected and evaluated for redox stress, lung injury/development, and inflammation using standard immunohistological techniques, morphometric analysis, and standard molecular assays. BALF cytokines were measured using a flow cytometric approach (BioLegend). Two-dimensional cell migration assays were tracked via microscopy daily until 100% confluence reached; the ½ maximal peak values were evaluated to compare rate of wound closure following very low (2.5 ng/mL) TNFα or IL12 treatment. Transepithelial resistance and potential differences were measured using an EVOM device (World Precision Instrument) across human small airway epithelial cells, and equivalent short circuit currents (Isc) calculated in accordance with Ohm’s Law, where V=IR. Single data comparisons were performed using paired Student’s t-tests. Multiple comparisons were performed using ANOVA followed by post-hoc testing in Sigma Plot. Results: FADH protected neonatal lungs from high oxygen induced oxidative stress: GSH/GSSG Eh (a measure of oxidative stress) improved from -168.77 mV ± 3.64 mV to -179.10 mV ± 1.85 mV (n=5 BALF measurements). FADH also improved lung injury scores from 0.187±0.038 to 0.03±0.014 (p=0.005), decreased neutrophil migration (p&lt;0.001), and increased macrophages (p&lt;0.001) when compared to age-matched untreated pups. FADH-mediated increase in TNFα (and not IL12) significantly increased the rate of lung epithelial cell wound closure from [2.27±0.07 to 1.97±0.1 average days for ½ complete wound closure, n=6, p=0.01] and increased Isc from 6.5±.21 to 9.2±1.0 μA/cm2, n=3, p=0.03. Conclusions: Our findings indicate that FADH protects the preterm lung from hyperoxic injury by 1) increasing the bioavailability of GSH and 2) via TNFα signaling to increase the rate of wound closure and repair of epithelial cell function. Significances: The mechanisms identified through this study could be targeted as a potential adjunct therapy for BPD patients to attenuate high oxygen induced lung injury. Funding: Supported by R01HL137033 (MH). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Social Support, Stress, and Mental Health: Examining the Stress-Buffering Hypothesis in Adolescent Football Athletes.

Football sport participation has been linked to both positive and negative effects on overall health. Social support, a network that provides individuals with resources to cope effectively, may positively influence one's stress and mental health. However, little research has been conducted on adolescent football players. To examine the relationships among social support, psychological stress, and mental health in adolescent football athletes. Cross-sectional study. High school athletes during the precompetitive and postcompetitive football season in rural Alabama. Black and African American adolescent athletes (N = 93) competing for a school-sponsored football team. After a competitive season, participants completed a battery of social support, psychological stress, and mental health symptom measures using the National Institutes of Health Toolbox Application and Patient-Reported Outcomes Measurement Information System. The T-score means, Pearson correlations, and multiple regression analyses were calculated. Social support was negatively correlated with psychological stress (emotional support, r = -0.386; family relationships, r = -0.412; peer relationships, r = -0.265) and mental health (depression, r = -0.367 and r = -0.323 for emotional support and family relationships, respectively), whereas psychological stress and mental health (depression, r = 0.751; anxiety, r = 0.732) were positively correlated. In regression analyses, social support measures (ie, emotional support, family relationships, and peer relationships) were used to predict psychological stress (F = 7.094, P < .001, R2 = 0.191), depression symptoms (F = 5.323, P < .001, R2 = 0.151), and anxiety symptoms (F = 1.644, P = .190, R2 = 0.052). In line with the stress-buffering hypothesis, social support in the form of family relationships and overall emotional support garnered through sport participation may reduce psychological stress and help to preserve the mental health of football athletes. These findings indicate that perceived social support may act as a positive resource for the coping of Black and African American adolescent athletes. Further research is warranted to understand the effects of stress and social support on the mental health of adolescents, particularly racial and ethnic minorities who are underrepresented in the athletic training literature.

Following community norms or an internal compass? The role of prospective leaders' social category membership in the differential effects of authentic and ethical leadership on stereotype threat.

Increasing racial diversity in organizations remains a challenge, as stereotype threat undermines the performance and career aspirations of minority group members during job recruitment. The present study examines how prospective leaders can leverage their influence on their followers' identities to mitigate the stereotype threat Black individuals face in this context. We explore the effects of two moral leadership styles (ethical vs. authentic) on stereotype threat in the context of recruitment. Specifically, we investigate whether prospective leaders' ingroup status moderates the relationship between ethical versus authentic leadership styles and candidates' stereotype threat during the selection process and candidates' willingness to join the organization. To this end, we conducted four experiments with Black residents of Brazilian favelas (impoverished neighborhoods), two of which included real-world job recruitment processes and physiological measures of stress (i.e., salivary cortisol and blood pressure). The results indicate that when the prospective leaders are from the outgroup, displaying ethical leadership by relying on community norms is more helpful in reducing Black candidates' threat and, in turn, promotes willingness to apply for the job. In contrast, when the leader is from the ingroup, displaying authentic leadership by emphasizing the importance of an internal moral compass is more helpful in reducing threat, and this effect is mediated by the identity process of inclusion of the leader in the self. Overall, the present study suggests that prospective direct supervisors have the critical ability to reduce stereotype threat, which can negatively affect Black applicants and their desire to join organizations. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Multiscale residual stress and mechanical behavior analysis in machining of Ti-6Al-4V alloy with advanced microscopic characterization

Machining of polycrystalline metal materials results in metallurgical modifications in the machined surface, and it can introduce multiscale residual stresses (macroscale and microscale residual stress), which may be detrimental to the mechanical properties thereby interfering with the service performance of machined parts. However, most of the current studies only focus on the macroscale residual stress, the microscale residual stresses have always been neglected since the limitations of the commonly used techniques for residual stress measurement in machined surfaces. In this study, the recently developed Focused Ion Beam-digital image correlation (FIB-DIC) ring core method was employed to evaluate the time-resolved strain relaxation and multiscale residual stress of the machined surface under different cutting conditions. The quantitative evaluation of residual stress and microstructural effects on hardness of the machined surface was conducted by combining with FIB incremental milling and nanoindentation technique. It has been observed that although the global tensile strain relaxation was captured in the ring-core region, local microscale compressive strain relaxation also occurred. The hardness of the machined surface was determined by the combined effects of microstructure and residual stress induced by machining. Specifically, the grain refinement and compressive residual stress contributed to hardening, while tensile residual stress resulted in softening of the machined surface. Furthermore, it was also observed the hardening/softening effects were enhanced with increasing intensity of tension and compression.