Synchronization of activity among myocytes constituting vital organs, e.g., the heart, is crucial for physiological functions. Self-organized coordination in such heterogeneous ensemble of excitable and oscillatory cells is therefore of clinical importance. We show by varying the strength of intercellular coupling and the electrophysiological diversity, a wide range of collective behavior emerges including clusters of synchronized activity. Strikingly, stretch-activated currents allow waves of mechanical deformation to alter the activity of neighboring cells, promoting robust global coherence.
{"title":"Mechanics promotes coherence in heterogeneous active media","authors":"Soling Zimik, Sitabhra Sinha","doi":"arxiv-2408.10603","DOIUrl":"https://doi.org/arxiv-2408.10603","url":null,"abstract":"Synchronization of activity among myocytes constituting vital organs, e.g.,\u0000the heart, is crucial for physiological functions. Self-organized coordination\u0000in such heterogeneous ensemble of excitable and oscillatory cells is therefore\u0000of clinical importance. We show by varying the strength of intercellular\u0000coupling and the electrophysiological diversity, a wide range of collective\u0000behavior emerges including clusters of synchronized activity. Strikingly,\u0000stretch-activated currents allow waves of mechanical deformation to alter the\u0000activity of neighboring cells, promoting robust global coherence.","PeriodicalId":501572,"journal":{"name":"arXiv - QuanBio - Tissues and Organs","volume":"30 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142183354","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Karsten Kruse, Rémi Berthoz, Luca Barberi, Anne-Cécile Reymann, Daniel Riveline
Stress generation by the actin cytoskeleton shapes cells and tissues. Despite impressive progress in live imaging and quantitative physical descriptions of cytoskeletal network dynamics, the connection between processes at molecular scales and cell-scale spatio-temporal patterns is still unclear. Here we review studies reporting acto-myosin clusters of micrometer size and with lifetimes of several minutes in a large number of organisms ranging from fission yeast to humans. Such structures have also been found in reconstituted systems in vitro and in theoretical analysis of cytoskeletal dynamics. We propose that tracking these clusters can serve as a simple readout for characterising living matter. Spatio-temporal patterns of clusters could serve as determinants of morphogenetic processes that play similar roles in diverse organisms.
{"title":"Acto-myosin clusters as active units shaping living matter","authors":"Karsten Kruse, Rémi Berthoz, Luca Barberi, Anne-Cécile Reymann, Daniel Riveline","doi":"arxiv-2408.05119","DOIUrl":"https://doi.org/arxiv-2408.05119","url":null,"abstract":"Stress generation by the actin cytoskeleton shapes cells and tissues. Despite\u0000impressive progress in live imaging and quantitative physical descriptions of\u0000cytoskeletal network dynamics, the connection between processes at molecular\u0000scales and cell-scale spatio-temporal patterns is still unclear. Here we review\u0000studies reporting acto-myosin clusters of micrometer size and with lifetimes of\u0000several minutes in a large number of organisms ranging from fission yeast to\u0000humans. Such structures have also been found in reconstituted systems in vitro\u0000and in theoretical analysis of cytoskeletal dynamics. We propose that tracking\u0000these clusters can serve as a simple readout for characterising living matter.\u0000Spatio-temporal patterns of clusters could serve as determinants of\u0000morphogenetic processes that play similar roles in diverse organisms.","PeriodicalId":501572,"journal":{"name":"arXiv - QuanBio - Tissues and Organs","volume":"3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141935877","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In silico testing of implant materials is a research area of high interest, as cost- and labour-intensive experiments may be omitted. However, assessing the tissue-material interaction mathematically and computationally can be very complex, in particular when functional, such as biodegradable, implant materials are investigated. In this work, we expand and refine suitable existing mathematical models of bone growth and magnesium-based implant degradation based on ordinary differential equations. We show that we can simulate the implant degradation, as well as the osseointegration in terms of relative bone volume fraction and changes in bone ultrastructure when applying the model to experimental data from titanium and magnesium-gadolinium implants for healing times up to 32 weeks. By conducting a parameter study we further show that a lack of data at early time points has little influence on the simulation outcome. Moreover, we show that the model is predictive in terms of relative bone volume fraction with mean absolute errors below 6%
{"title":"Computational modelling of bone growth and mineralization surrounding biodegradable Mg-based and permanent Ti implants","authors":"Domenik Priebe, Nik Pohl, Tamadur AlBaraghtheh, Sven Schimek, Florian Wieland, Diana Krüger, Sascha Trostorff, Regine Willumeit-Römer, Ralf Köhl, Berit Zeller-Plumhoff","doi":"arxiv-2408.03820","DOIUrl":"https://doi.org/arxiv-2408.03820","url":null,"abstract":"In silico testing of implant materials is a research area of high interest,\u0000as cost- and labour-intensive experiments may be omitted. However, assessing\u0000the tissue-material interaction mathematically and computationally can be very\u0000complex, in particular when functional, such as biodegradable, implant\u0000materials are investigated. In this work, we expand and refine suitable\u0000existing mathematical models of bone growth and magnesium-based implant\u0000degradation based on ordinary differential equations. We show that we can\u0000simulate the implant degradation, as well as the osseointegration in terms of\u0000relative bone volume fraction and changes in bone ultrastructure when applying\u0000the model to experimental data from titanium and magnesium-gadolinium implants\u0000for healing times up to 32 weeks. By conducting a parameter study we further\u0000show that a lack of data at early time points has little influence on the\u0000simulation outcome. Moreover, we show that the model is predictive in terms of\u0000relative bone volume fraction with mean absolute errors below 6%","PeriodicalId":501572,"journal":{"name":"arXiv - QuanBio - Tissues and Organs","volume":"195 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141935876","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A data fitting procedure is devised and thoroughly tested to provide self-consistent estimates of the relevant mechanokinetic parameters involved in a plausible scheme underpinning the output of an ensemble of myosin II molecular motors mimicking the muscle contraction. The method builds on a stochastic model accounting for the force exerted by the motor ensemble operated both in the low and high force-generating regimes corresponding to different temperature ranges. The proposed interpretative framework is successfully challenged against simulated data, meant to mimic the experimental output of a unidimensional synthetic nanomachine powered by pure muscle myosin isoforms.
{"title":"Resolving the kinetics of an ensemble of muscle myosin motors via a temperature-dependent fitting procedure","authors":"Valentina Buonfiglio, Niccolò Zagli, Irene Pertici, Vincenzo Lombardi, Pasquale Bianco, Duccio Fanelli","doi":"arxiv-2408.03676","DOIUrl":"https://doi.org/arxiv-2408.03676","url":null,"abstract":"A data fitting procedure is devised and thoroughly tested to provide\u0000self-consistent estimates of the relevant mechanokinetic parameters involved in\u0000a plausible scheme underpinning the output of an ensemble of myosin II\u0000molecular motors mimicking the muscle contraction. The method builds on a\u0000stochastic model accounting for the force exerted by the motor ensemble\u0000operated both in the low and high force-generating regimes corresponding to\u0000different temperature ranges. The proposed interpretative framework is\u0000successfully challenged against simulated data, meant to mimic the experimental\u0000output of a unidimensional synthetic nanomachine powered by pure muscle myosin\u0000isoforms.","PeriodicalId":501572,"journal":{"name":"arXiv - QuanBio - Tissues and Organs","volume":"22 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141935871","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Indentation tests are classical tools to determine material properties. For biological samples such as cysts of cells, however, the observed force-displacement relation cannot be expected to follow predictions for simple materials. Here, by solving the Pogorelov problem of a point force indenting an elastic shell for a purely nonlinear material, we discover that complex material behaviour can even give rise to new scaling exponents in this force-displacement relation. In finite-element simulations, we show that these exponents are surprisingly robust, persisting even for thick shells indented with a sphere. By scaling arguments, we generalise our results to pressurised and pre-stressed shells, uncovering additional new scaling exponents. We find these predicted scaling exponents in the force-displacement relation observed in cyst indentation experiments. Our results thus form the basis for inferring the mechanisms that set the mechanical properties of these biological materials.
{"title":"Mechanics of poking a cyst","authors":"Shiheng Zhao, Pierre A. Haas","doi":"arxiv-2408.03716","DOIUrl":"https://doi.org/arxiv-2408.03716","url":null,"abstract":"Indentation tests are classical tools to determine material properties. For\u0000biological samples such as cysts of cells, however, the observed\u0000force-displacement relation cannot be expected to follow predictions for simple\u0000materials. Here, by solving the Pogorelov problem of a point force indenting an\u0000elastic shell for a purely nonlinear material, we discover that complex\u0000material behaviour can even give rise to new scaling exponents in this\u0000force-displacement relation. In finite-element simulations, we show that these\u0000exponents are surprisingly robust, persisting even for thick shells indented\u0000with a sphere. By scaling arguments, we generalise our results to pressurised\u0000and pre-stressed shells, uncovering additional new scaling exponents. We find\u0000these predicted scaling exponents in the force-displacement relation observed\u0000in cyst indentation experiments. Our results thus form the basis for inferring\u0000the mechanisms that set the mechanical properties of these biological\u0000materials.","PeriodicalId":501572,"journal":{"name":"arXiv - QuanBio - Tissues and Organs","volume":"48 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141935745","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Atherosclerosis, a chronic inflammatory cardiovascular disease, leads to arterial constriction caused by the accumulation of lipids, cholesterol, and various substances within artery walls. Such plaque can rupture, resulting in a blood clot that obstructs major arteries and may initiate myocardial infarction, ischemic stroke, etc. Atherosclerotic plaque formation begins with the accumulation of foam cells and macrophages within the intima layer of the arterial wall. At the latter stage, the smooth muscle cells migrated from deeper artery wall layers, contributing to the fibrous cap formation and plaque stabilizing. A developed plaque gradually enters the lumen and narrows down the lumen to impede blood flow. We introduce a two-phase and macroscopic model to investigate the progression of plaque growth in its advanced stage and analyze the minimum gap (Lumen Clearance) within an atherosclerotic artery so that blood cells can pass through. Cardiac troponin, a high specificity and sensitivity biomarker, facilitates early detection of elevated myocardial infarction, Ischemic stroke, etc. risks. This study aims to establish a relationship between the troponin concentration in atherosclerotic arteries and their internal clearance, which could significantly improve our understanding of disease progression. Our observations show that the plaque undergoes rapid evolution in its initial stages, gradually slowing down over time to reach a steady state. At the same time, the lumen clearance exhibits an opposite behavior, decreasing slowly over time. Our study finds a positive correlation between plaque depth and troponin concentration in the blood and a negative relationship between troponin concentrations and lumen clearance in atherosclerotic arteries.
{"title":"The Role of Biomarkers on Haemodynamics in Atherosclerotic Artery","authors":"Ruchira Ray, Bibaswan Dey","doi":"arxiv-2408.03117","DOIUrl":"https://doi.org/arxiv-2408.03117","url":null,"abstract":"Atherosclerosis, a chronic inflammatory cardiovascular disease, leads to\u0000arterial constriction caused by the accumulation of lipids, cholesterol, and\u0000various substances within artery walls. Such plaque can rupture, resulting in a\u0000blood clot that obstructs major arteries and may initiate myocardial\u0000infarction, ischemic stroke, etc. Atherosclerotic plaque formation begins with\u0000the accumulation of foam cells and macrophages within the intima layer of the\u0000arterial wall. At the latter stage, the smooth muscle cells migrated from\u0000deeper artery wall layers, contributing to the fibrous cap formation and plaque\u0000stabilizing. A developed plaque gradually enters the lumen and narrows down the\u0000lumen to impede blood flow. We introduce a two-phase and macroscopic model to\u0000investigate the progression of plaque growth in its advanced stage and analyze\u0000the minimum gap (Lumen Clearance) within an atherosclerotic artery so that\u0000blood cells can pass through. Cardiac troponin, a high specificity and\u0000sensitivity biomarker, facilitates early detection of elevated myocardial\u0000infarction, Ischemic stroke, etc. risks. This study aims to establish a\u0000relationship between the troponin concentration in atherosclerotic arteries and\u0000their internal clearance, which could significantly improve our understanding\u0000of disease progression. Our observations show that the plaque undergoes rapid\u0000evolution in its initial stages, gradually slowing down over time to reach a\u0000steady state. At the same time, the lumen clearance exhibits an opposite\u0000behavior, decreasing slowly over time. Our study finds a positive correlation\u0000between plaque depth and troponin concentration in the blood and a negative\u0000relationship between troponin concentrations and lumen clearance in\u0000atherosclerotic arteries.","PeriodicalId":501572,"journal":{"name":"arXiv - QuanBio - Tissues and Organs","volume":"16 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141935746","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Faezeh Ghobadi, Maryam Saadatmand, Sara Simorgh, Peiman Brouki Milan
We engineered a microfluidic platform to study the effects of bioactive glass nanoparticles (BGNs) on cell viability under static culture. We incorporated different concentrations of BGNs (1%, 2%, and 3% w/v) in collagen hydrogel (with a concentration of 3.0 mg/mL). The microfluidic chip's dimensions were optimized through fluid flow and mass transfer simulations. Collagen type I extracted from rat tail tendons was used as the main material, and BGNs synthesized by the sol-gel method were used to enhance the mechanical properties of the hydrogel. The extracted collagen was characterized using FTIR and SDS-PAGE, and BGNs were analyzed using XRD, FTIR, DLS, and FE-SEM/EDX. The structure of the collagen-BGNs hydrogels was examined using SEM, and their mechanical properties were determined using rheological analysis. The cytotoxicity of BGNs was assessed using the MTT assay, and the viability of fibroblast (L929) cells encapsulated in the collagen-BGNs hydrogel inside the microfluidic device was assessed using a live/dead assay. Based on all these test results, the L929 cells showed high cell viability in vitro and promising microenvironment mimicry in a microfluidic device. Collagen3-BGNs3 (Collagen 3 mg/mL + BGNs 3% (w/v)) was chosen as the most suitable sample for further research on a microfluidic platform.
{"title":"Microfluidic 3D Cell Culture: Potential Application of Collagen Hydrogels with an Optimal Dose of Bioactive Glasses","authors":"Faezeh Ghobadi, Maryam Saadatmand, Sara Simorgh, Peiman Brouki Milan","doi":"arxiv-2408.03196","DOIUrl":"https://doi.org/arxiv-2408.03196","url":null,"abstract":"We engineered a microfluidic platform to study the effects of bioactive glass\u0000nanoparticles (BGNs) on cell viability under static culture. We incorporated\u0000different concentrations of BGNs (1%, 2%, and 3% w/v) in collagen hydrogel\u0000(with a concentration of 3.0 mg/mL). The microfluidic chip's dimensions were\u0000optimized through fluid flow and mass transfer simulations. Collagen type I\u0000extracted from rat tail tendons was used as the main material, and BGNs\u0000synthesized by the sol-gel method were used to enhance the mechanical\u0000properties of the hydrogel. The extracted collagen was characterized using FTIR\u0000and SDS-PAGE, and BGNs were analyzed using XRD, FTIR, DLS, and FE-SEM/EDX. The\u0000structure of the collagen-BGNs hydrogels was examined using SEM, and their\u0000mechanical properties were determined using rheological analysis. The\u0000cytotoxicity of BGNs was assessed using the MTT assay, and the viability of\u0000fibroblast (L929) cells encapsulated in the collagen-BGNs hydrogel inside the\u0000microfluidic device was assessed using a live/dead assay. Based on all these\u0000test results, the L929 cells showed high cell viability in vitro and promising\u0000microenvironment mimicry in a microfluidic device. Collagen3-BGNs3 (Collagen 3\u0000mg/mL + BGNs 3% (w/v)) was chosen as the most suitable sample for further\u0000research on a microfluidic platform.","PeriodicalId":501572,"journal":{"name":"arXiv - QuanBio - Tissues and Organs","volume":"21 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141935872","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Salem Mosleh, Emil Annevelink, Venkatasubramanian Viswanathan, L. Mahadevan
Safe, all-solid-state lithium metal batteries enable high energy density applications, but suffer from instabilities during operation that lead to rough interfaces between the metal and electrolyte and subsequently cause void formation and dendrite growth that degrades performance and safety. Inspired by the morphogenetic control of thin lamina such as tree leaves that robustly grow into flat shapes -- we propose a range of approaches to control lithium metal stripping and plating. To guide discovery of materials that will implement these feedback mechanisms, we develop a reduced order model that captures couplings between mechanics, interface growth, temperature, and electrochemical variables. We find that long-range feedback is required to achieve true interface stability, while approaches based on local feedback always eventually grow into rough interfaces. All together, our study provides the beginning of a practical framework for analyzing and designing stable electrochemical interfaces in terms of the mechanical properties and the physical chemistry that underlie their dynamics.
{"title":"Controlling moving interfaces in solid state batteries","authors":"Salem Mosleh, Emil Annevelink, Venkatasubramanian Viswanathan, L. Mahadevan","doi":"arxiv-2408.03175","DOIUrl":"https://doi.org/arxiv-2408.03175","url":null,"abstract":"Safe, all-solid-state lithium metal batteries enable high energy density\u0000applications, but suffer from instabilities during operation that lead to rough\u0000interfaces between the metal and electrolyte and subsequently cause void\u0000formation and dendrite growth that degrades performance and safety. Inspired by\u0000the morphogenetic control of thin lamina such as tree leaves that robustly grow\u0000into flat shapes -- we propose a range of approaches to control lithium metal\u0000stripping and plating. To guide discovery of materials that will implement\u0000these feedback mechanisms, we develop a reduced order model that captures\u0000couplings between mechanics, interface growth, temperature, and electrochemical\u0000variables. We find that long-range feedback is required to achieve true\u0000interface stability, while approaches based on local feedback always eventually\u0000grow into rough interfaces. All together, our study provides the beginning of a\u0000practical framework for analyzing and designing stable electrochemical\u0000interfaces in terms of the mechanical properties and the physical chemistry\u0000that underlie their dynamics.","PeriodicalId":501572,"journal":{"name":"arXiv - QuanBio - Tissues and Organs","volume":"30 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141935875","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Valentina Buonfiglio, Irene Pertici, Matteo Marcello, Ilaria Morotti, Marco Caremani, Massimo Reconditi, Marco Linari, Duccio Fanelli, Vincenzo Lombardi, Pasquale Bianco
Myosin II is the muscle molecular motor that works in two bipolar arrays in each thick filament of the striated (skeletal and cardiac) muscle, converting the chemical energy into steady force and shortening by cyclic ATP--driven interactions with the nearby actin filaments. Different isoforms of the myosin motor in the skeletal muscles account for the different functional requirements of the slow muscles (primarily responsible for the posture) and fast muscles (responsible for voluntary movements). To clarify the molecular basis of the differences, here the isoform--dependent mechanokinetic parameters underpinning the force of slow and fast muscles are defined with a unidimensional synthetic nanomachine powered by pure myosin isoforms from either slow or fast rabbit skeletal muscle. Data fitting with a stochastic model provides a self--consistent estimate of all the mechanokinetic properties of the motor ensemble including the motor force, the fraction of actin--attached motors and the rate of transition through the attachment--detachment cycle. The achievements in this paper set the stage for any future study on the emergent mechanokinetic properties of an ensemble of myosin molecules either engineered or purified from mutant animal models or human biopsies.
肌球蛋白Ⅱ是肌肉分子马达，它在横纹肌（骨骼肌和心肌）每条粗丝的两个双极阵列中工作，通过与附近肌动蛋白丝的循环 ATP 驱动相互作用，将化学能转化为稳定的力量和缩短。由于骨骼肌中肌球蛋白运动的同工形式不同，慢肌（主要负责姿势）和快肌（负责自主运动）的功能要求也不同。为了阐明这种差异的分子基础，本文通过一个由纯兔慢肌或快肌肌球蛋白同工酶驱动的单维合成纳米机器，定义了支撑慢肌和快肌力量的同工酶依赖性机械动力学参数。随机模型的数据拟合为运动组合的所有机械动力学特性提供了自我一致的估计，包括运动力、肌动蛋白附着运动的比例以及附着-分离循环的转换率。本文的研究成果为今后研究从突变动物模型或人体活组织中设计或纯化的肌球蛋白分子集合的新机械动力学特性奠定了基础。
{"title":"Force and kinetics of fast and slow muscle myosin determined with a synthetic sarcomere-like nanomachine","authors":"Valentina Buonfiglio, Irene Pertici, Matteo Marcello, Ilaria Morotti, Marco Caremani, Massimo Reconditi, Marco Linari, Duccio Fanelli, Vincenzo Lombardi, Pasquale Bianco","doi":"arxiv-2408.00373","DOIUrl":"https://doi.org/arxiv-2408.00373","url":null,"abstract":"Myosin II is the muscle molecular motor that works in two bipolar arrays in\u0000each thick filament of the striated (skeletal and cardiac) muscle, converting\u0000the chemical energy into steady force and shortening by cyclic ATP--driven\u0000interactions with the nearby actin filaments. Different isoforms of the myosin\u0000motor in the skeletal muscles account for the different functional requirements\u0000of the slow muscles (primarily responsible for the posture) and fast muscles\u0000(responsible for voluntary movements). To clarify the molecular basis of the\u0000differences, here the isoform--dependent mechanokinetic parameters underpinning\u0000the force of slow and fast muscles are defined with a unidimensional synthetic\u0000nanomachine powered by pure myosin isoforms from either slow or fast rabbit\u0000skeletal muscle. Data fitting with a stochastic model provides a\u0000self--consistent estimate of all the mechanokinetic properties of the motor\u0000ensemble including the motor force, the fraction of actin--attached motors and\u0000the rate of transition through the attachment--detachment cycle. The\u0000achievements in this paper set the stage for any future study on the emergent\u0000mechanokinetic properties of an ensemble of myosin molecules either engineered\u0000or purified from mutant animal models or human biopsies.","PeriodicalId":501572,"journal":{"name":"arXiv - QuanBio - Tissues and Organs","volume":"75 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141883938","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sepsis is a lethal syndrome of organ dysfunction that is triggered by an infection and claims 11 million lives per year globally. Prognostic algorithms based on deep learning have shown promise in detecting the onset of sepsis hours before the actual event but use a large number of bio-markers, including vital signs and laboratory tests. The latter makes the deployment of such systems outside hospitals or in resource-limited environments extremely challenging. This paper introduces SepAl, an energy-efficient and lightweight neural network, using only data from low-power wearable sensors, such as photoplethysmography (PPG), inertial measurement units (IMU), and body temperature sensors, designed to deliver alerts in real-time. SepAl leverages only six digitally acquirable vital signs and tiny machine learning algorithms, enabling on-device real-time sepsis prediction. SepAl uses a lightweight temporal convolution neural network capable of providing sepsis alerts with a median predicted time to sepsis of 9.8 hours. The model has been fully quantized, being able to be deployed on any low-power processors, and evaluated on an ARM Cortex-M33 core. Experimental evaluations show an inference efficiency of 0.11MAC/Cycle and a latency of 143ms, with an energy per inference of 2.68mJ. This work aims at paving the way toward accurate disease prediction, deployable in a long-lasting multi-vital sign wearable device, suitable for providing sepsis onset alerts at the point of care. The code used in this work has been open-sourced and is available at https://github.com/mgiordy/sepsis-prediction
{"title":"SepAl: Sepsis Alerts On Low Power Wearables With Digital Biomarkers and On-Device Tiny Machine Learning","authors":"Marco Giordano, Kanika Dheman, Michele Magno","doi":"arxiv-2408.08316","DOIUrl":"https://doi.org/arxiv-2408.08316","url":null,"abstract":"Sepsis is a lethal syndrome of organ dysfunction that is triggered by an\u0000infection and claims 11 million lives per year globally. Prognostic algorithms\u0000based on deep learning have shown promise in detecting the onset of sepsis\u0000hours before the actual event but use a large number of bio-markers, including\u0000vital signs and laboratory tests. The latter makes the deployment of such\u0000systems outside hospitals or in resource-limited environments extremely\u0000challenging. This paper introduces SepAl, an energy-efficient and lightweight\u0000neural network, using only data from low-power wearable sensors, such as\u0000photoplethysmography (PPG), inertial measurement units (IMU), and body\u0000temperature sensors, designed to deliver alerts in real-time. SepAl leverages\u0000only six digitally acquirable vital signs and tiny machine learning algorithms,\u0000enabling on-device real-time sepsis prediction. SepAl uses a lightweight temporal convolution neural network capable of\u0000providing sepsis alerts with a median predicted time to sepsis of 9.8 hours.\u0000The model has been fully quantized, being able to be deployed on any low-power\u0000processors, and evaluated on an ARM Cortex-M33 core. Experimental evaluations\u0000show an inference efficiency of 0.11MAC/Cycle and a latency of 143ms, with an\u0000energy per inference of 2.68mJ. This work aims at paving the way toward\u0000accurate disease prediction, deployable in a long-lasting multi-vital sign\u0000wearable device, suitable for providing sepsis onset alerts at the point of\u0000care. The code used in this work has been open-sourced and is available at\u0000https://github.com/mgiordy/sepsis-prediction","PeriodicalId":501572,"journal":{"name":"arXiv - QuanBio - Tissues and Organs","volume":"55 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142183355","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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