Hasil untuk "Physiology"

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arXiv Open Access 2025
Electromechanical human heart modeling for predicting endocardial heart motion

Milad Hasani, Alireza Rezania, Sam Riahi

This work presents a biventricular electromechanical human heart model that is comprehensive and clinically relevant, integrating a realistic 3D heart geometry with both systemic and pulmonary hemodynamics. The model uses a two-way fluid-structure-interaction (FSI) formulation with actual 3D blood meshes to accurately investigate the effect of blood flow on the myocardium. It couples a reaction-diffusion framework and a voltage-dependent active stress term to replicate the link between electrical excitation and mechanical contraction. Additionally, the model incorporates innovative epicardial boundary conditions to mimic the stiffness and viscosity of neighboring tissues. The model's ability to replicate physiological heart motion was validated against Cine magnetic resonance imaging (MRI) data, which demonstrated a high degree of consistency in regional displacement patterns. The analysis of the right ventricle showed that the basal and mid free walls experience the largest motion, making these regions ideal for implanting motion-driven energy harvesting devices. This validated model is a robust tool for enhancing our understanding of cardiac physiology and optimizing therapeutic interventions before clinical implementation.

en physics.med-ph, math.NA
arXiv Open Access 2025
Pressure-Free Surface-Induced Flow by Geometric Rectification

Zheng Li

Pressure-driven flow collapses when confined ($u\propto r^{2}$). Asymmetry rectifies surface activity (exchange or slip gradients) into axial flux at $ΔP=0$ despite zero net exchange. Lorentz reciprocity yields a projection law: throughput is the inner product of source with a geometry kernel. Signatures include inverted ``narrower-is-faster'' scaling ($u\propto r^{-1}$), leading-order viscosity independence, length amplification ($Q\propto L$), and linear superposition, defining surface-induced flow as a pressure-free Stokes-transport mode from microfluidics to physiology.

en physics.flu-dyn
arXiv Open Access 2025
Adding a Storage Pool improves 3-PG Tree-ring Simulations

Yanfang Wang, Liang Wei, Liheng Zhong et al.

Tree rings provide long-term records of tree growth and climate changes, which makes them ideal benchmarks for forest modeling. Tree-ring information has greatly improved the reliability of 3-PG, which is one of the most commonly used process-based forest growth models. Here we strengthen 3-PGs ability to simulate tree-ring width and carbon stable isotopes (δ13C) by enhancing its descriptions of tree physiology. The major upgrade was adding a carbon storage pool for tree-ring formation using stored carbohydrates. We also incorporated previous modifications (replacing the age modifier with a height modifier) of 3-PG and tested their efficacy in improving tree-ring simulations. We ran the model based on two grand fir (Abies grandis) stands. The updated model greatly improved the simulations for both tree-ring widths and δ13C. The results represent one of the best tree-ring δ13C simulations, which accurately captured the amplitude in annual variations of δ13C. The correlations (R2) between simulations and observations reached 0.50 and 0.73 at two stands respectively. The new model also greatly improved the simulations of raw tree-ring widths and detrended ring-widths index. Because of better descriptions of tree physiology and more accurate simulations of tree rings than the previous model version, the updated 3-PG should provide more reliable simulations than previous 3-PG versions when tree-ring information is used as benchmark in future studies.

en q-bio.QM
arXiv Open Access 2025
StARS DCM: A Sleep Stage-Decoding Forehead EEG Patch for Real-time Modulation of Sleep Physiology

William G. Coon, Preston Peranich, Griffin Milsap

The System to Augment Restorative Sleep (StARS) is a modular hardware/software platform designed for real-time sleep monitoring and intervention. Utilizing the compact DCM biosignal device, StARS captures electrophysiological signals (EEG, EMG, EOG) and synchronizes sensor data using the ezmsg real-time software framework. StARS supports interventions such as closed-loop auditory stimulation and dynamic thermal modulation guided by sleep-stage decoding via advanced neural network models and transfer learning. Configurable with a lightweight EEG forehead patch or wearable sensors like smart rings, StARS offers flexible, low-burden solutions for EEG, BCI, and sleep-enhancement research and applications. The open-source DCM patch further enables customizable EEG device development.

en eess.SP
arXiv Open Access 2025
Application of a Virtual Imaging Framework for Investigating a Deep Learning-Based Reconstruction Method for 3D Quantitative Photoacoustic Computed Tomography

Refik Mert Cam, Seonyeong Park, Umberto Villa et al.

Quantitative photoacoustic computed tomography (qPACT) is a promising imaging modality for estimating physiological parameters such as blood oxygen saturation. However, developing robust qPACT reconstruction methods remains challenging due to computational demands, modeling difficulties, and experimental uncertainties. Learning-based methods have been proposed to address these issues but remain largely unvalidated. Virtual imaging (VI) studies are essential for validating such methods early in development, before proceeding to less-controlled phantom or in vivo studies. Effective VI studies must employ ensembles of stochastically generated numerical phantoms that accurately reflect relevant anatomy and physiology. Yet, most prior VI studies for qPACT relied on overly simplified phantoms. In this work, a realistic VI testbed is employed for the first time to assess a representative 3D learning-based qPACT reconstruction method for breast imaging. The method is evaluated across subject variability and physical factors such as measurement noise and acoustic aberrations, offering insights into its strengths and limitations.

en physics.med-ph, cs.AI
DOAJ Open Access 2025
The effect of endurance, resistance and concurrent training on respiratory capacity of cystic fibrosis patients

Ashkan Sohrabi, Samaneh Ebrahimi, Ehsan Arabzadeh et al.

Cystic fibrosis (CF) is a multisystem disease that may affect organ systems, including the respiratory system. Exercise training provides multiple benefits for people with CF. The purpose of this study was to determine the effects of three exercise-training programs on respiratory capacity and pulmonary function in patients with CF. Sixty CF patients (age 8–15 years, body mass index or BMI > 16 kg/m2) were randomly allocated to three experimental groups including: Endurance training (ET, n = 15), Resistance training (RT, n = 15), Concurrent Training (CT, n = 14) and control (C, n = 16). Trainings groups completed a 10-week moderate exercise programs (endurance, resistance and concurrent modality). Spirometry was performed both prior to randomization and following the intervention to assess first second of forced expiration (FEV1), forced vital capacity (FVC) and FEV1/FVC ratio. Health-related quality of life (HRQoL) was assessed using the adolescent/adult version of the CF Questionnaire. The results show that 10-weeks of supervised ET, RT and CT improved FEV1, FVC, FEV1/FVC (%), peak expiratory flow (PEF) (l/s), forced mid-expiratory flow (FEF) 25–75 % (l/s), maximal voluntary ventilation (MVV) dimension, and HRQoL (p < 0.05). In addition, in the three exercise groups, a significant improvement in all variables at post-test was observed when compared to pre-test (p < 0.05). In CF patients, performing controlled endurance, resistance and combined exercises improved functional and respiratory parameters. However, it seems that combined exercises had a greater effect on these variables than resistance and endurance exercises alone.

Sports medicine
arXiv Open Access 2024
Exploring Emotions in Multi-componential Space using Interactive VR Games

Rukshani Somarathna, Gelareh Mohammadi

Emotion understanding is a complex process that involves multiple components. The ability to recognise emotions not only leads to new context awareness methods but also enhances system interaction's effectiveness by perceiving and expressing emotions. Despite the attention to discrete and dimensional models, neuroscientific evidence supports those emotions as being complex and multi-faceted. One framework that resonated well with such findings is the Component Process Model (CPM), a theory that considers the complexity of emotions with five interconnected components: appraisal, expression, motivation, physiology and feeling. However, the relationship between CPM and discrete emotions has not yet been fully explored. Therefore, to better understand emotions underlying processes, we operationalised a data-driven approach using interactive Virtual Reality (VR) games and collected multimodal measures (self-reports, physiological and facial signals) from 39 participants. We used Machine Learning (ML) methods to identify the unique contributions of each component to emotion differentiation. Our results showed the role of different components in emotion differentiation, with the model including all components demonstrating the most significant contribution. Moreover, we found that at least five dimensions are needed to represent the variation of emotions in our dataset. These findings also have implications for using VR environments in emotion research and highlight the role of physiological signals in emotion recognition within such environments.

en cs.HC, cs.AI
DOAJ Open Access 2024
Associations of adverse childhood experiences with blood pressure among early adolescents in the United States

Abubakr A.A. Al-shoaibi, Christopher M. Lee, Julia H. Raney et al.

The associations of adverse childhood experiences (ACEs) with blood pressure in adulthood are inconclusive. Similarly, the association between ACEs and blood pressure earlier in the life course is understudied. This study aims to assess the associations of ACEs with blood pressure among early adolescents. We utilized data collected at baseline (age: 9–10 years) and Year 2 follow-up from 4077 participants in the Adolescent Brain Cognitive Development (ABCD) Study. We used adjusted multiple linear regression models to estimate the associations of ACEs (cumulative score and subtypes) at baseline with systolic blood pressure (SBP) and diastolic blood pressure (DBP) at year 2 of follow-up. Experiencing ≥4 ACEs (compared to 0) was significantly associated with higher SBP (B = 3.31, 95 % CI 0.03, 6.57, p = 0.048). Of the ACEs subtypes, household substance use (B = 2.28, 95 % CI 0.28, 4.28, p = 0.028) and divorce or separation (B = 2.08, 95 % CI 0.01, 4.15, p = 0.048) were both significantly associated with a higher SBP while household mental illness (B = 2.57, 95 % CI 1.32, 3.81, p < 0.001) was significantly associated with a higher DBP. Our findings suggest that exposure to multiple ACEs is associated with higher blood pressure in adolescence.

Diseases of the circulatory (Cardiovascular) system, Public aspects of medicine
DOAJ Open Access 2024
Laser amygdalohippocampotomy reduces contralateral hippocampal sub-clinical activity in bitemporal epilepsy: A case illustration of responsive neurostimulator ambulatory recordings

Hael F. Abdulrazeq, Anna R. Kimata, Belinda Shao et al.

Responsive neurostimulation (RNS) is a valuable tool in the diagnosis and treatment of medication refractory epilepsy (MRE) and provides clinicians with better insights into patients’ seizure patterns. In this case illustration, we present a patient with bilateral hippocampal RNS for presumed bilateral mesial temporal lobe epilepsy. The patient subsequently underwent a right sided LITT amygdalohippocampotomy based upon chronic RNS data revealing predominance of seizures from that side. Analyzing electrocorticography (ECOG) from the RNS system, we identified the frequency of high amplitude discharges recorded from the left hippocampal lead pre- and post- right LITT amygdalohippocampotomy. A reduction in contralateral interictal epileptiform activity was observed through RNS recordings over a two-year period, suggesting the potential dependency of the contralateral activity on the primary epileptogenic zone. These findings suggest that early targeted surgical resection or laser ablation by leveraging RNS data can potentially impede the progression of dependent epileptiform activity and may aid in preserving neurocognitive networks. RNS recordings are essential in shaping further management decisions for our patient with a presumed bitemporal epilepsy.

Neurology. Diseases of the nervous system, Neurophysiology and neuropsychology
DOAJ Open Access 2024
Ethanolic Extracts of Cissus quadrangularis Linn. (Vitaceae) Attenuate Vincristine-Induced Peripheral Neuropathy in Rats: An Evidence of the Antioxidant, Calcium Inhibitory, and Neuromodulatory Properties

Feigni Youyi Marcelle Olga, Mbiantcha Marius, Yousseu Nana William et al.

Cissus quadrangularis Linn. (C. quadrangularis, Vitaceae) is a plant reported to treat injured tendons, broken bones, asthma, stomach ache, scurvy, and digestive disorders. The present study evaluated the antihyperalgesic effects of ethanolic extract of C. quadrangularis Linn. Vincristine sulfate (100 μg/kg, i.p.) was administered in rats for 10 days with 2 days break to induce painful peripheral neuropathy. Mechanical hyperalgesia and allodynia tests were performed to assess the threshold of painful neuropathy. Calcium levels in the sciatic nerve, oxidant stress markers, and levels of GABA and 5-HT were also determined in the brain and spinal cord after 15 days. Ethanolic extract of C. quadrangularis (180 and 360 mg/kg) and pregabalin (50 mg/kg) were administered for 15 consecutive days. The results revealed that the extract significantly (p<0.001) inhibited hyperalgesia and allodynia in animals after vincristine administration. The extract decreased total calcium levels in the sciatic nerve, MDA levels while increasing GSH activity, 5-HT level, as well as GABA levels in the brain and spinal cord. The results of this study suggest that the ethanolic extract of C. quadrangularis uses antioxidant capacity, calcium inhibitory action, and neuromodulation of GABA and 5-HT to prevent the development of painful neuropathy after vincristine administration. This demonstrates that C. quadrangularis is a promising molecule for the management of peripheral neuropathic pain induced by anticancer drugs.

Therapeutics. Pharmacology
DOAJ Open Access 2024
Indicadores de carga externa e interna según el sexo durante un torneo congestionado juvenil de balonmano costarricense

Daniel Rojas-Valverde, Jose Pino-Ortega, Carlos Gómez-Carmona et al.

El objetivo de la investigación fue identificar los indicadores de carga externa e interna en balonmano juvenil durante un torneo congestionado en Costa Rica, seleccionando variables a través de Análisis de Componentes Principales (ACP) como técnica de reducción de datos, y determinar si existen diferencias entre sexo. Los datos se obtuvieron de 73 jugadores juveniles de balonmano (33 mujeres y 38 hombres) de ocho clubes locales durante un torneo de partidos congestionados de 3 días. Se analizaron doce partidos (seis masculinos y seis femeninos) utilizando ACP y una prueba t-Student independiente para las diferencias relacionadas entre sexos. Se identificaron seis indicadores principales de carga, cinco de carga externa [distancia relativa (DR); cantidad de aceleraciones (AceR), aceleración máxima (AceMáx), velocidad máxima (VMáx), y diferencia entre aceleraciones y deceleraciones (DfAce-Dec)] y uno de carga interna [frecuencia cardíaca media (FCmedia)]. En hombres, los indicadores más representativos fueron la DR, la FCmedia y AceMáx, explicaron el 39,6% de la varianza. En mujeres fueron la VMáx y AceMáx explicando el 44,4% de la varianza. AceR (p< 0,01), AceMáx (p< 0,01), VMáx (p< 0,01) fueron mayores en hombres respecto a las mujeres. Mientras que la FCmedia (p= 0,02) fue mayor en mujeres que hombres. Se concluye que la carga externa e interna mostró diferencias entre jugadores masculinos y femeninos. Hombres caracterizados por variables asociadas con el volumen, mientras que, para las mujeres fueron más comunes indicadores relacionados con la intensidad. Para torneos congestionados, es importante individualizar según sexo las cargas de entrenamiento, así como priorizar las cualidades físicas a entrenar.

Recreation. Leisure, Sports
arXiv Open Access 2023
Regulation of store-operated calcium entry

Goutham Kodakandla, Askar Akimzhanov, Darren Boehning

Plasma membrane calcium influx through ion channels is crucial for many events in cellular physiology. Cell surface stimuli lead to the production of inositol 1,4,5-trisphosphate (IP3), which binds to IP3 receptors in the endoplasmic reticulum (ER) to release calcium pools from the ER lumen. This leads to depletion of ER calcium pools which has been termed store-depletion. Store-depletion leads the dissociation of calcium ions from the EF-hand motif of the ER calcium sensor Stromal Interaction Molecule 1 (STIM1). This leads to a conformational change in STIM1 which helps it to interact with a plasma membrane (PM) at ER:PM junctions. At these ER:PM junctions, STIM1 binds to and activates a calcium channel known as Orai1 to form calcium-release activated calcium (CRAC) channels. Activation of Orai1 leads to calcium influx, known as store-operated calcium entry (SOCE). In addition to Orai1 and STIM1, the homologs of Orai1 and STIM1, such as Orai2/3 and STIM2 also play a crucial role in calcium homeostasis. The influx of calcium through the Orai channel activates a calcium current that has been termed CRAC currents. CRAC channels form multimers and cluster together in large macromolecular assemblies termed puncta. How these CRAC channels form puncta has been contentious since their discovery. In this review, we will outline the history of SOCE, the molecular players involved in this process (Orai and STIM proteins, TRP channels, SOCE-associated regulatory factor etc.), as well as the models that have been proposed to explain this important mechanism in cellular physiology.

en q-bio.CB, q-bio.SC
DOAJ Open Access 2023
Evaluation of Agro-Industrial Carbon and Energy Sources for <i>Lactobacillus plantarum</i> M8 Growth

José Escurra, Francisco P. Ferreira, Tomás R. López et al.

Lactic acid is a compound used industrially due to its properties. There are two methods for its production: chemical synthesis and microbial fermentation. In microbial fermentation, food industry waste can be used as a substrate, providing a route towards achieving a circular economy. Thus, this study evaluated different substrates for <i>Lactobacillus plantarum</i> growth, a lactic acid producer, such as molasses, whey, glucose, and saccharose, either alone or supplemented with additional nutrients. Bacterial growth parameters were assessed using OD<sub>620</sub> measurement. It was shown that whey supplemented with yeast extract supported the best growth, allowing a μ<sub>max</sub> = 0.63 h<sup>−1</sup>.

Plant ecology, Animal biochemistry
DOAJ Open Access 2023
Subcutaneous Mycobacterium vaccae ameliorates the effects of early life adversity alone or in combination with chronic stress during adulthood in male and female mice

Giulia Mazzari, Christopher A. Lowry, Dominik Langgartner et al.

Chronic psychosocial stress is a burden of modern society and poses a clear risk factor for a plethora of somatic and affective disorders, of which most are associated with an activated immune status and chronic low-grade inflammation. Preclinical and clinical studies further suggest that a failure in immunoregulation promotes an over-reaction of the inflammatory stress response and, thus, predisposes an individual to the development of stress-related disorders. Therefore, all genetic (i.e., sex) and environmental (i.e., early life adversity; ELA) factors facilitating an adult's inflammatory stress response are likely to increase their stress vulnerability.In the present study we investigated whether repeated subcutaneous (s.c.) administrations with a heat-killed preparation of Mycobacterium vaccae (M. vaccae; National Collection of Type Cultures (NCTC) 11659), an abundant soil saprophyte with immunoregulatory properties, are protective against negative behavioral, immunological and physiological consequences of ELA alone or of ELA followed by chronic psychosocial stress during adulthood (CAS) in male and female mice. ELA was induced by the maternal separation (MS) paradigm, CAS was induced by 19 days of chronic subordinate colony housing (CSC) in males and by a 7-week exposure to the social instability paradigm (SIP) in females.Our data indicate that ELA effects in both sexes, although relatively mild, were to a great extent prevented by subsequent s.c. M. vaccae administrations. Moreover, although the use of different paradigms for males and females impedes a direct comparison, male mice seemed to be more susceptible to CAS than females, with only females benefitting slightly from the stress protective effects of s.c. M. vaccae administrations when given prior to CAS alone. Finally, our data support the hypothesis that female mice are more vulnerable to the additive effects of ELA and CAS than male mice and that s.c. M. vaccae administrations subsequent to ELA but prior to CAS are protective in both sexes.Taken together and considering the limitation that CAS in males and females was induced by different paradigms, our findings are consistent with the hypotheses that murine stress vulnerability during different phases of life is strongly sex dependent and that developing immunoregulatory approaches, such as repeated s.c. administrations with immunoregulatory microorganisms, have potential for prevention/treatment of stress-related disorders.

Neurosciences. Biological psychiatry. Neuropsychiatry, Neurology. Diseases of the nervous system
arXiv Open Access 2022
Sparse algorithms for EEG source localization

Teja Mannepalli, Aurobinda Routray

Source localization using EEG is important in diagnosing various physiological and psychiatric diseases related to the brain. The high temporal resolution of EEG helps medical professionals assess the internal physiology of the brain in a more informative way. The internal sources are obtained from EEG by an inversion process. The number of sources in the brain outnumbers the number of measurements. In this article, a comprehensive review of the state of the art sparse source localization methods in this field is presented. A recently developed method, certainty based reduced sparse solution (CARSS), is implemented and is examined. A vast comparative study is performed using a sixty four channel setup involving two source spaces. The first source space has 5004 sources and the other has 2004 sources. Four test cases with one, three, five, and seven simulated active sources are considered. Two noise levels are also being added to the noiseless data. The CARSS is also evaluated. The results are examined. A real EEG study is also attempted.

arXiv Open Access 2022
A Level Set Kalman Filter Approach to Estimate the Circadian Phase and its Uncertainty from Wearable Data

Dae Wook Kim, Minki P. Lee, Daniel B. Forger

The circadian clock is an internal timer that coordinates the daily rhythms of behavior and physiology, including sleep and hormone secretion. Accurately tracking the state of the circadian clock, or circadian phase, holds immense potential for precision medicine. Wearable devices present an opportunity to estimate the circadian phase in the real world, as they can non-invasively monitor various physiological outputs influenced by the circadian clock. However, accurately estimating circadian phase from wearable data remains challenging, primarily due to the lack of methods that integrate minute-by-minute wearable data with prior knowledge of the circadian phase. To address this issue, we propose a framework that integrates multi-time scale physiological data to estimate the circadian phase, along with an efficient implementation algorithm based on Bayesian inference and a new state space estimation method called the level set Kalman filter. Our numerical experiments indicate that our approach outperforms previous methods for circadian phase estimation consistently. Furthermore, our method enables us to examine the contribution of noise from different sources to the estimation, which was not feasible with prior methods. We found that internal noise unrelated to external stimuli is a crucial factor in determining estimation results. Lastly, we developed a user-friendly computational package and applied it to real-world data to demonstrate the potential value of our approach. Our results provide a foundation for systematically understanding the real-world dynamics of the circadian clock.

en math.DS
arXiv Open Access 2022
Complexity Synchronization

Korosh Mahmoodi, Scott E. Kerick, Paolo Grigolini et al.

The observational ubiquity of inverse power law spectra (IPL) in complex phenomena entails theory for dynamic fractal phenomena capturing their fractal dimension, dynamics, and statistics. These and other properties are consequences of the complexity resulting from nonlinear dynamic networks collectively summarized for biomedical phenomena as the Network Effect (NE) or focused more narrowly as Network Physiology. Herein we address the measurable consequences of the NE on time series generated by different parts of the brain, heart, and lung organ networks, which are directly related to their inter-network and intra-network interactions. Moreover, these same physiologic organ networks have been shown to generate crucial event (CE) time series, and herein are shown, using modified diffusion entropy analysis (MDEA), to have scaling indices with quasiperiodic changes in complexity, as measured by scaling indices, over time. Such time series are generated by different parts of the brain, heart, and lung organ networks, and the results do not depend on the underlying coherence properties of the associated time series but demonstrate a generalized synchronization of complexity. This high order synchrony among the scaling indices of EEG (brain), ECG (heart), and respiratory time series is governed by the quantitative interdependence of the multifractal behavior of the various physiological organs' network dynamics. This consequence of the NE opens the door for an entirely general characterization of the dynamics of complex networks in terms of complexity synchronization (CS) independently of the scientific, engineering, or technological context.

en nlin.AO, q-bio.QM
DOAJ Open Access 2022
Physical Activity, Muscle Oxidative Capacity, and Coronary Artery Calcium in Smokers with and without COPD

Tiller NB, Kinninger A, Abbasi A et al.

Nicholas B Tiller,1 April Kinninger,2 Asghar Abbasi,1 Richard Casaburi,1 Harry B Rossiter,1 Matthew J Budoff,2 Alessandra Adami3 1Institute of Respiratory Medicine and Exercise Physiology, Division of Respiratory and Critical Care Physiology and Medicine, The Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, CA, USA; 2Division of Cardiology, The Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, CA, USA; 3Department of Kinesiology, University of Rhode Island, Kingston, RI, USACorrespondence: Harry B Rossiter, Institute of Respiratory Medicine and Exercise Physiology, Division of Respiratory and Critical Care Physiology and Medicine, The Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, 1124 W. Carson Street, CDCRC Building, Torrance, CA, 90502, USA, Tel +1 310-222-8200, Email hrossiter@lundquist.orgIntroduction: Severe chronic obstructive pulmonary disease (COPD) is partly characterized by diminished skeletal muscle oxidative capacity and concurrent dyslipidemia. It is unknown whether such metabolic derangements increase the risk of cardiovascular disease. This study explored associations among physical activity (PA), muscle oxidative capacity, and coronary artery calcium (CAC) in COPDGene participants.Methods: Data from current and former smokers with COPD (n = 75) and normal spirometry (n = 70) were retrospectively analyzed. Physical activity was measured for seven days using triaxial accelerometry (steps/day and vector magnitude units [VMU]) along with the aggregate of self-reported PA amount and PA difficulty using the PROactive D-PPAC instrument. Muscle oxidative capacity (k) was assessed via near-infrared spectroscopy, and CAC was assessed via chest computerized tomography.Results: Relative to controls, COPD patients exhibited higher CAC (median [IQR], 31 [0– 431] vs 264 [40– 799] HU; p = 0.003), lower k (mean ± SD = 1.66 ± 0.48 vs 1.25 ± 0.37 min− 1; p < 0.001), and lower D-PPAC total score (65.2 ± 9.9 vs 58.8 ± 13.2; p = 0.003). Multivariate analysis—adjusting for age, sex, race, diabetes, disease severity, hyperlipidemia, smoking status, and hypertension—revealed a significant negative association between CAC and D-PPAC total score (β, − 0.05; p = 0.013), driven primarily by D-PPAC difficulty score (β, − 0.03; p = 0.026). A 1 unit increase in D-PPAC total score was associated with a 5% lower CAC (p = 0.013). There was no association between CAC and either k, steps/day, VMU, or D-PPAC amount.Conclusion: Patients with COPD and concomitantly elevated CAC exhibit greater perceptions of difficulty when performing daily activities. This may have implications for exercise adherence and risk of overall physical decline.Keywords: coronary artery calcium, COPD, muscle, oxidative capacity, physical activity, respiratory

Diseases of the respiratory system
DOAJ Open Access 2022
Effects of Different Types of Exercise on Kidney Diseases

Hamid Arazi, Majid Mohabbat, Payam Saidie et al.

The effects of exercise on kidney function have been studied for more than three decades. One of the most common health issues among patients with chronic kidney disease (CKD) is a lack of physical activity, which leads to a low exercise capacity in these patients. The majority of maintenance hemodialysis (MHD) patients do not exercise at all. At each stage of dialysis, patients lose 10–12 g of their amino acids through blood sampling. Dialysis also leads to increased cortisol and circadian rhythm sleep disorders in hemodialysis (HD) patients. Studies have also reported higher C-reactive protein levels in HD patients, which causes arterial stiffness. Exercise has a variety of health benefits in these patients, including improved blood pressure control, better sleep, higher physical function, and reduced anxiety and depression. On the other hand, it should be noted that intense exercise has the potential to progress KD, especially when conducted in hot weather with dehydration. This review aimed to investigate the effects of different types of exercise on kidney disease and provide exercise guidelines. In conclusion, moderate-intensity and long-term exercise (for at least a 6-month period), with consideration of the principles of exercise (individualization, intensity, time, etc.), can be used as an adjunctive treatment strategy in patients undergoing dialysis or kidney transplantation.

DOAJ Open Access 2022
Effects of compression running pants and treadmill running stages on knee proprioception and fatigue-related physiological responses in half-marathon runners

Lin Chang, Silin Fu, Jianghua Li et al.

Background: Knee injury is common in half-marathon runners, however, the effect of compression running pants on fatigue and knee proprioception remains unclear.Objectives: The study aims to investigate whether wearing compression running pants (CRP) and treadmill running stages affect knee proprioception and fatigue-related physiological responses during half-marathon running.Methods: Eighteen half-marathon runners completed two self-paced 21 km treadmill running trials, once wearing CRP and once wearing loose running shorts (LRS). For each 21 km run, RPE, heart rate, blood lactic acid, and knee flexion proprioception were assessed before starting, and after each 7 km stage.Results: Data analysis revealed no difference between CRP and LRS conditions in heart rate, RPE, or blood lactic acid. Repeated measures ANOVA showed a significant garment condition main effect whereby wearing CRP was associated with higher knee proprioceptive acuity (p = 0.006). Polynomial trend analysis showed a significant linear downwards trend in proprioceptive acuity across the four measurement occasions (p = 0.048). Stage analysis showed that wearing CRP was associated with better knee proprioception at running distances of 14 km (p = 0.007, 95%CI = -0.054, -0.010) and 21 km (p = 0.016, 95%CI = -0.051, -0.006).Conclusion: Compression running pants provide an overall positive effect on knee proprioception, particularly after 14 km and 21km, which may reduce the probability of knee injury. CRP had no significant effect on physiological measures in half-marathon running.

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