Hasil untuk "Physiology"

D. Hubel, T. Wiesel

Sayantan Nag Chowdhury, Hildegard Meyer-Ortmanns

Non-reciprocal couplings are frequently found in systems out-of-equilibrium such as neuronal networks. We consider generalized Kuramoto models with non-reciprocal adaptive couplings. The non-reciprocity refers to the type of couplings according to Hebbian or anti-Hebbian rules and to different time scales on which the couplings evolve. The main effect of this specific combination of deterministic dynamics is an induced metastability of anti-phase synchronized clusters of oscillators. Metastable switching is typical for neuronal networks and a characteristic of brain dynamics. We analyze the metastability as a function of the system parameters, in particular of the size and the network connectivity. The mechanism behind sudden changes in the order parameters is individual oscillators which change their cluster affiliation from time to time, providing ``weak ties" between clusters of synchronized oscillators, where an individual oscillator may represent an entire brain area. The time series exhibit random features but arise from deterministic dynamics.

Aakanksha J Shetty, Alexei Sirbu, Paolo Annibale

G protein-coupled receptors (GPCRs) represent a diverse and vital family of membrane proteins that mediate intracellular signaling in response to extracellular stimuli, playing critical roles in physiology and disease. Traditionally recognized as chemical signal transducers, GPCRs have recently been implicated in mechanotransduction, the process of converting mechanical stimuli into cellular responses. This review explores the emerging role of GPCRs in sensing and responding to mechanical forces, with a particular focus on the cardiovascular system. Cardiovascular homeostasis is heavily influenced by mechanical forces such as shear stress, cyclic stretch, and pressure, which are central to both normal physiology and the pathogenesis of diseases like hypertension and atherosclerosis. GPCRs, including the angiotensin II type 1 receptor (AT1R) and the \b{eta}2-adrenergic receptor (\b{eta}2-AR), have demonstrated the ability to integrate mechanical and chemical signals, potentially through conformational changes and/or modulation of lipid interactions, leading to biased signaling. Recent studies highlight the dual activation mechanisms of GPCRs, with \b{eta}2-AR now serving as a key example of how mechanical and ligand-dependent pathways contribute to cardiovascular regulation. This review synthesizes current knowledge of GPCR mechanosensitivity, emphasizing its implications for cardiovascular health and disease, and explores advancements in methodologies poised to further unravel the mechanistic intricacies of these receptors.

Soroosh Sabeti, Nicholas B. Larson, Judy C. Boughey et al.

Abstract Background Angiogenic activity of cancerous breast tumors can be impacted by neoadjuvant chemotherapy (NAC), thus potentially serving as a marker for response monitoring. While different imaging modalities can aid in evaluation of tumoral vascular changes, ultrasound-based approaches are particularly suitable for clinical use due to their availability and noninvasiveness. In this paper, we make use of quantitative high-definition microvasculature imaging (qHDMI) based on contrast-free ultrasound for assessment of NAC response in breast cancer patients. Methods Patients with invasive breast cancer recommended treatment with NAC were included in the study and ultrafast ultrasound data were acquired at pre-NAC, mid-NAC, and post-NAC time points. Data acquisitions also took place at two additional timepoints – at two and four weeks after NAC initiation in a subset of patients. Ultrasound data frames were processed within the qHDMI framework to visualize the microvasculature in and around the breast tumors. Morphological analyses on the microvasculature structure were performed to obtain 12 qHDMI biomarkers. Pathology from surgery classified response using residual cancer burden (RCB) and was used to designate patients as responders (RCB 0/I) and non-responders (RCB II/III). Distributions of imaging biomarkers across the two groups were analyzed using Wilcoxon rank-sum test. The trajectories of biomarker values over time were investigated and linear mixed effects models were used to evaluate interactions between time and group for each biomarker. Results Of the 53 patients included in the study, 32 (60%) were responders based on their RCB status. The results of linear mixed effects model analysis showed statistically significant interactions between group and time in six out of the 12 qHDMI biomarkers, indicating differences in trends of microvascular morphological features by responder status. In particular, vessel density (p-value: 0.023), maximum tortuosity (p-value: 0.049), maximum diameter (p-value: 0.002), fractal dimension (p-value: 0.002), mean Murray’s deviation (p-value: 0.034), and maximum Murray’s deviation (p-value: 0.022) exhibited significantly different trends based on responder status. Conclusions We observed microvasculature changes in response to NAC in breast cancer patients using qHDMI as an objective and quantitative contrast-free ultrasound framework. These finding suggest qHDMI may be effective in identifying early response to NAC.

Katelyn E. Mooney, Derek B. Archer, Aditi Sathe et al.

Abstract INTRODUCTION We assessed associations between apolipoprotein E Translocase of Outer Mitochondrial Membrane 40 (APOE‐TOMM40)‐‘523 haplotypes and white matter microstructure (WMM) across limbic tracts important for memory and cognition in non‐Hispanic Black and White individuals. METHODS Linear regression models, stratified by APOE and racialized groups, assessed associations between TOMM40‐‘523‐S and limbic tract WMM free‐water (FW) and free‐water‐corrected fractional anisotropy (FAFWcorr). RESULTS Black‐ε4+‐one‐'523‐S carriers had lower FW in the cingulum and inferior longitudinal fasciculus compared to Black‐ε4+‐no‐'523‐S carriers. Additionally, Black‐ε4+‐one‐'523‐S carriers had lower FW in the cingulum, uncinate, and fornix, and higher FAFWcorr in the uncinate compared to Black‐ε4+‐'523‐S/S carriers. White‐ε3/ε3‐‘523‐S/S carriers had lower FAFWcorr in the cingulum and inferior temporal gyrus compared to White‐ε3/ε3‐no‐'523‐S carriers, and lower FAFWcorr in the cingulum compared to White‐ε3/ε3‐one‐‘523‐S carriers. DISCUSSION This supports prior work that ‘523‐S is associated with abnormal aging in White‐ε3/ε3 carriers, but is potentially risk‐mitigating in Black‐ε4+ carriers, while suggesting a differential effect by racialized background of APOE on WMM. Highlights White matter microstructure (WMM) across limbic tracts important for cognition was measured by diffusion MRI. Black apolipoprotein E (APOE) ε4+ carriers with one copy of TOMM40‐‘523‐S had normal aging WMM metrics across several tracts, including the cingulum bundle, uncinate fasciculus, fornix, and inferior longitudinal fasciculus. White APOE ε3/ε3 carriers with two copies of TOMM40‐‘523‐S had abnormal aging WMM metrics in the cingulum bundle and inferior temporal gyrus. APOE associations with aging may differ in racialized groups due to TOMM40‐‘523‐S copy number.

Xinjian Li, Lin Mi, Juntao Duan et al.

INTRODUCTION: Revascularization of nonculprit arteries in patients with ST-Segment Elevation Myocardial Infarction (STEMI) is now recommended based on several trials. However, the optimal therapeutic strategy of nonculprit lesions remains unknown. Murray law-based Quantitative Flow Ratio (μQFR) is a novel, non-invasive, vasodilator‐free method for evaluating the functional severity of coronary artery stenosis, which has potential applications for nonculprit lesion assessment in STEMI patients. MATERIAL AND METHODS: Patients with STEMI who received staged PCI before hospital discharge were enrolled retrospectively. μQFR analyses of nonculprit vessels were performed based on both acute and staged angiography. RESULTS: : Eighty-four patients with 110 nonculprit arteries were included. The mean acute μQFR was 0.76 ± 0.18, and the mean staged μQFR was 0.75 ± 0.19. The average period between acute and staged evaluation was 8 days. There was a good correlation (r = 0.719, P < 0.001) between acute μQFR and staged μQFR. The classification agreement was 89.09%. The area under the receiver operator characteristic (ROC) curve for detecting staged μQFR ≤ 0.80 was 0.931. CONCLUSIONS: : It is feasible to calculate the μQFR during the acute phase of STEMI patients. Acute μQFR and staged μQFR have a good correlation and agreement. The μQFR could be a valuable method for assessing functional significance of nonculprit arteries in STEMI patients.

Raeva Petya, Ivanova Snezhana

After Covid 19, hazards appeared for the development of the hotel and restaurant business. Some of the skilled personnel left this business and headed for more sustainable industries or abroad. Therefore, the aim of the work is to study the main factors affecting the survival and prospects for the development of the restaurant business in the hotel-restaurant complexes in Bulgaria. The main motivations of consumers for the future development of modern restaurants in the country aimed at increasing customer satisfaction have been studied. The research was conducted through qualitative and quantitative marketing research and SWOT analysis of available high-end hotels and dining and entertainment establishments in Bulgaria. Mathematical and statistical models were used to process the data of the respondents for each of the questions. The results are presented graphically. A comparative characterization of six hotel-restaurant chains in Bulgaria was made in terms of categorization, comfort, amenities and quality of service, and way of eating in the restaurants. The positive sides and their shortcomings and prospects for development in the current economic situation are reflected, and the consequences of the Covid 19 crisis are also taken into account.

Michael J. Bennington, Tuo Wang, Jiaguo Yin et al.

The McKibben pneumatic artificial muscle is a commonly studied soft robotic actuator, and its quasistatic force-length properties have been well characterized and modeled. However, its damping and force-velocity properties are less well studied. Understanding these properties will allow for more robust dynamic modeling of soft robotic systems. The force-velocity response of these actuators is of particular interest because these actuators are often used as hardware models of skeletal muscles for bioinspired robots, and this force-velocity relationship is fundamental to muscle physiology. In this work, we investigated the force-velocity response of McKibben actuators and the ability to tune this response through the use of viscoelastic polymer sheaths. These viscoelastic McKibben actuators (VMAs) were characterized using iso-velocity experiments inspired by skeletal muscle physiology tests. A simplified 1D model of the actuators was developed to connect the shape of the force-velocity curve to the material parameters of the actuator and sheaths. Using these viscoelastic materials, we were able to modulate the shape and magnitude of the actuators' force-velocity curves, and using the developed model, these changes were connected back to the material properties of the sheaths.

Amanda Z. Zucoloto, Jared Schlechte, Aline Ignacio et al.

Summary: During bloodstream infections, neutrophils home to the liver as part of an intravascular immune response to eradicate blood-borne pathogens, but the mechanisms regulating this crucial response are unknown. Using in vivo imaging of neutrophil trafficking in germ-free and gnotobiotic mice, we demonstrate that the intestinal microbiota guides neutrophil homing to the liver in response to infection mediated by the microbial metabolite D-lactate. Commensal-derived D-lactate augments neutrophil adhesion in the liver independent of granulopoiesis in bone marrow or neutrophil maturation and activation in blood. Instead, gut-to-liver D-lactate signaling primes liver endothelial cells to upregulate adhesion molecule expression in response to infection and promote neutrophil adherence. Targeted correction of microbiota D-lactate production in a model of antibiotic-induced dysbiosis restores neutrophil homing to the liver and reduces bacteremia in a model of Staphylococcus aureus infection. These findings reveal long-distance traffic control of neutrophil recruitment to the liver by microbiota-endothelium crosstalk.

Julia L. Larson, Henry T. Robertson, Henry T. Robertson et al.

Introduction: Trauma is the leading cause of death in persons under the age of 45. Recovery in patients who survive initial trauma are frequently complicated by sequelae of injury that increases susceptibility to infection and inflammation. Uncontrolled inflammation can advance into life-threatening organ failure, including acute respiratory distress syndrome (ARDS). Similarities exist between biomarkers established in the etiology of acute respiratory distress syndrome and those identified in the acute inflammatory and healing phase of bone fractures. This study investigates the impact of long bone fractures on the development of acute respiratory distress syndrome where it is hypothesized that patients with long bone fractures would have different biomarker profiles and increased development of lung injury compared to patients without long bone fractures.Methods: This is a retrospective data analysis of patients from an observational data repository from three trauma centers. Trauma patients with and without long bone fractures were matched and analyzed for the presence of known biomarkers of acute respiratory distress syndrome and for the development of acute respiratory distress syndrome.Results: There were no differences in overall acute respiratory distress syndrome development or hospital outcomes, however long bone fracture patients had a 2.35-fold higher hazard ratio of acute respiratory distress syndrome in the first 10 hospital days. There was a statistically significant increase in the levels of IL-6 in patients with long bone fractures (p = .0007). Structural equations modeling demonstrated that IL-6 was positively influenced by long bone fractures and IL-8.Conclusion: The presence of long bone fractures did not result in differences in the overall development of acute respiratory distress syndrome or hospital outcomes, though was found to have an increased hazard ratio for acute respiratory distress syndrome development in the first 10 days. Further research is needed to better characterize the relationship between varying cytokine profiles and the development of acute respiratory distress syndrome in a trauma population.

Alfonso Varela-López, José M. Romero-Márquez, María D. Navarro-Hortal et al.

The rise of life expectancy in current societies is not accompanied, to date, by a similar increase in healthspan, which represents a great socio-economic problem. It has been suggested that aging can be manipulated and then, the onset of all age-associated chronic disorders can be delayed because these pathologies share age as primary underlying risk factor. One of the most extended ideas is that aging is consequence of the accumulation of molecular damage. According to the oxidative damage theory, antioxidants should slow down aging, extending lifespan and healthspan. The present review analyzes studies evaluating the effect of dietary antioxidants on lifespan of different aging models and discusses the evidence on favor of their antioxidant activity as anti-aging mechanisms. Moreover, possible causes for differences between the reported results are evaluated.

Marco Fedele, Roberto Piersanti, Francesco Regazzoni et al.

While ventricular electromechanics is extensively studied, four-chamber heart models have only been addressed recently; most of these works however neglect atrial contraction. Indeed, as atria are characterized by a complex physiology influenced by the ventricular function, developing computational models able to capture the physiological atrial function and atrioventricular interaction is very challenging. In this paper, we propose a biophysically detailed electromechanical model of the whole human heart that considers both atrial and ventricular contraction. Our model includes: i) an anatomically accurate whole-heart geometry; ii) a comprehensive myocardial fiber architecture; iii) a biophysically detailed microscale model for the active force generation; iv) a 0D closed-loop model of the circulatory system; v) the fundamental interactions among the different core models; vi) specific constitutive laws and model parameters for each cardiac region. Concerning the numerical discretization, we propose an efficient segregated-intergrid-staggered scheme and we employ recently developed stabilization techniques that are crucial to obtain a stable formulation in a four-chamber scenario. We are able to reproduce the healthy cardiac function for all the heart chambers, in terms of pressure-volume loops, time evolution of pressures, volumes and fluxes, and three-dimensional cardiac deformation, with unprecedented matching (to the best of our knowledge) with the expected physiology. We also show the importance of considering atrial contraction, fibers-stretch-rate feedback and suitable stabilization techniques, by comparing the results obtained with and without these features in the model. The proposed model represents the state-of-the-art electromechanical model of the iHEART ERC project and is a fundamental step toward the building of physics-based digital twins of the human heart.

Xiaoxin Song, Fei Wu, Xiaotong Lu et al.

Extraction of farming progress information in rice–wheat rotation regions is an important topic in smart field research. In this study, a new method for the classification of farming progress types using unmanned aerial vehicle (UAV) RGB images and the proposed regional mean (RM) model is presented. First, RGB information was extracted from the images to create and select the optimal color indices. After index classification, we compared the brightness reflection of the corresponding grayscale map, the classification interval, and the standard deviation of each farming progress type. These comparisons showed that the optimal classification color indices were the normalized red–blue difference index (NRBDI), the normalized green–blue difference index (NGBDI), and the modified red–blue difference index (MRBDI). Second, the RM model was built according to the whole-field farming progress classification requirements to achieve the final classification. We verified the model accuracy, and the Kappa coefficients obtained by combining the NRBDI, NGBDI, and MRBDI with the RM model were 0.86, 0.82, and 0.88, respectively. The proposed method was then applied to predict UAV RGB images of unharvested wheat, harvested wheat, and tilled and irrigated fields. The results were compared with those obtained with traditional machine learning methods, that is, the support vector machine, maximum likelihood classification, and random forest methods. The NRBDI, NGBDI, and MRBDI were combined with the RM model to monitor farming progress of ground truth ROIs, and the Kappa coefficients obtained were 0.9134, 0.8738, and 0.9179, respectively, while traditional machine learning methods all produced a Kappa coefficient less than 0.7. The results indicate a significantly higher accuracy of the proposed method than those of the traditional machine learning classification methods for the identification of farming progress type. The proposed work provides an important reference for the application of UAV to the field classification of progress types.

Abdallah Alomari, Ebtesam khamees, Ahmad Kamel

The term indoor environmental quality is often confused with the term indoor air quality, but the term indoor environmental quality is larger and more comprehensive than the term indoor air quality , indoor air quality is a main part of indoor environmental quality which includes indoor air quality, the sustainable design has focused on the issue of the quality of the interior environment, as the sustainable interior design provides for achieving the quality of the interior environment by applying some special standards that are concerned with the quality of the interior air and the requirements of human comfort, the principle of internal environmental quality stipulates ensuring an internal environment in the dwelling that satisfies its residents, and this is done by providing fresh air inside the dwelling that does not cause harm to humans, by ensuring a good ventilation for the house, using building materials, interior finishing materials, furniture with low emissions and volatile materials, the requirement of thermal comfort should also be fulfilled by the temperature and humidity appropriate to the physiology of the human body, It is also necessary to secure the appropriate amount of lighting in the interior spaces of the dwelling by relying on natural lighting during the day. Achieving indoor environmental quality helps reduce the amount of energy consumed inside the dwelling, maintaining human health and preserving the natural environment , the quality of the internal environment is achieved by taking advantage of the climatic characteristics of the place in which the house is to be constructed, climatic characteristics mean the movement of the sun and the movement of the prevailing winds, as these elements must be used to help achieve the quality of the internal environment, the Jordanian guide for green buildings stipulated that the quality of the internal environment is met through some special standards, as these standards clarify the method of achieving the quality of the internal environment in the dwelling, it also evaluates it through earned points that show the extent to which the internal environment of the residence is compatible with these standards. The most important results obtained through the research were that the application of the internal environment quality standards of the Jordanian standard for green buildings benefits the natural environment and the residents of these dwellings, The standards of the guide helps to provide a healthy indoor environment that is free of contaminants and meets human comfort requirements.

Jörg Encke, Mathias Dietz

Sound in noise is better detected or understood if target and masking sources originate from different locations. Mammalian physiology suggests that the neurocomputational process that underlies this binaural unmasking is based on two hemispheric channels that encode interaural differences in their relative neuronal activity. Here, we introduce a mathematical formulation of the two-channel model - the complex-valued correlation coefficient. We show that this formulation quantifies the amount of temporal fluctuations in interaural differences, which we suggest underlie binaural unmasking. We applied this model to an extensive library of psychoacoustic experiments, accounting for 98% of the variance across eight studies. Combining physiological plausibility with its success in explaining behavioral data, the proposed mechanism is a significant step towards a unified understanding of binaural unmasking and the encoding of interaural differences in general.

Daniel McDuff, Ewa Nowara

What breathes life into an embodied agent or avatar? While body motions such as facial expressions, speech and gestures have been well studied, relatively little attention has been applied to subtle changes due to underlying physiology. We argue that subtle pulse signals are important for creating more lifelike and less disconcerting avatars. We propose a method for animating blood flow patterns, based on a data-driven physiological model that can be used to directly augment the appearance of synthetic avatars and photo-realistic faces. While the changes are difficult for participants to "see", they significantly more frequently select faces with blood flow as more anthropomorphic and animated than faces without blood flow. Furthermore, by manipulating the frequency of the heart rate in the underlying signal we can change the perceived arousal of the character.

Luciana Bergamasco, Lily N. Edwards-Callaway, Nora M. Bello et al.

Castration is a common management procedure employed in North American cattle production and is known to cause a pain response. The present study was designed to investigate the effect of unmitigated surgical castration on the electroencephalography (EEG) responses and plasma substance P (SP) concentrations in calves of different ages under the same experimental conditions. Thirty male Holstein calves in three age categories [<6 weeks (6W); 3 months (3M); 6 months (6M); 10 calves per age group] were used in the study. Calves were subjected to a simulated castration session (SHAM) followed 24 h later by surgical castration (CAST) without analgesia. An EEG analysis was performed before the procedure (i.e., baseline), at treatment, and 0–5, 5–10, and 10–20 min post-treatment for both SHAM and CAST, respectively. Blood samples were collected immediately prior to both treatments (time 0) and again at 1, 2, 4, 8, and 12 h after both treatments. The EEG results showed a three-way interaction between treatment, age, and time for delta and beta absolute power, beta relative power, total power, and median frequency (<i>p</i> = 0.004, <i>p</i> = 0.04, <i>p</i> = 0.04, <i>p</i> = 0.03, and <i>p</i> = 0.008, respectively). Following CAST, EEG total power decreased, and median frequency increased relative to SHAM in 6W and 3M calves only following treatment. For 6W and 3M calves, delta and beta absolute power increased at CAST and at later time points relative to SHAM. Marginal evidence for two-way interactions was noted between time and treatment and between age and treatment on the concentration of SP (<i>p</i> = 0.068 and <i>p</i> = 0.066, respectively). Substance P concentrations decreased in CAST treatment compared to SHAM at the later times (8 h: <i>p</i> = 0.007; 12 h: <i>p</i> = 0.048); 6W calves showed lower SP concentration at CAST relative to SHAM (<i>p</i> = 0.017). These findings indicate variation in EEG responses and in SP concentrations following unmitigated surgical castration in calves and that these responses may be age specific. These EEG findings have implications for supporting the perception of the pain associated with surgical castration in young calves and emphasize the urgency of pain mitigation strategies during routine husbandry practices such as castration, as typically implemented in North American cattle management.

Mengfei Liu, Sheng Cao, Li He et al.

Alcoholic hepatitis is characterized by intense liver inflammation driven by excessive cytokines and chemokines production and immune cell infiltration. Here the authors identify a super-enhancer that regulates the expression of multiple CXCL chemokines in alcoholic hepatitis and may be a potential therapeutic target.

J. M. Wakeling, S. A. Ross, D. S. Ryan et al.

During contraction the energy of muscle tissue increases due to energy from the hydrolysis of ATP. This energy is distributed across the tissue as strain-energy potentials in the contractile elements, strain-energy potential from the 3D deformation of the base-material tissue (containing cellular and ECM effects), energy related to changes in the muscle's nearly incompressible volume and external work done at the muscle surface. Thus, energy is redistributed through the muscle's tissue as it contracts, with only a component of this energy being used to do mechanical work and develop forces in the muscle's line-of-action. Understanding how the strain-energy potentials are redistributed through the muscle tissue will help enlighten why the mechanical performance of whole muscle in its line-of-action does not match the performance that would be expected from the contractile elements alone. Here we demonstrate these physical effects using a 3D muscle model based on the finite element method. The tissue deformations within contracting muscle are large, and so the mechanics of contraction were explained using the principles of continuum mechanics for large deformations. We present simulations of a contracting medial gastrocnemius muscle, showing tissue deformations that mirror observations from MRI-based images. This paper tracks the redistribution of strain-energy potentials through the muscle tissue during isometric contractions, and shows how fibre shortening, pennation angle, transverse bulging and anisotropy in the stress and strain of the muscle tissue are all related to the interaction between the material properties of the muscle and the action of the contractile elements.

Michał Krzyżowski, Bartosz Baran, Bartosz Łozowski et al.

This study explores the influence of rosemary, <i>Rosmarinus officinalis</i> (L.) essential oil (EO) on the biochemical (acetylcholinesterase, catalase, and glutathione S-transferase), physiological (oxygen consumption), and behavioral (open field test, repellency) parameters of an important stored product insect: cowpea weevil, <i>Callosobruchus maculatus</i> (F.). <i>R. officinalis</i> EO exhibited effective insecticidal action against <i>C. maculatus</i> even at relatively low concentrations. LC₅₀ = 15.69 μL/L air, and was highly repellent at concentrations equal to or above LC₂₅. Statistically significant inhibition in locomotor activity occurred only after the acute exposure to the EO at LC_12.5 and LC₂₅. The oxygen consumption test showed metabolism increase only at LC₅₀. An increase in activity was observed in the case of all three enzymes examined. The presented data provides a potentially valuable resource in designing more environmentally friendly and safer insecticide agents.