Intracellular calcium signaling in osteocytes:A mechano-transduction-mechano paradigm

Osteocytes in vivo are embedded in the mineralized extracellular bone matrix,where their cell bodies reside in the lacunae and are interconnected to neighboring osteocytes through numerous intercellular processes.The 3-dimensional（3D）osteocyte network positioning and ability to communicate with other bone cells make osteocytes ideal mechanosensors of bone.Thus the role of osteocyte network and intercellular communication between osteocytes in response to mechanical stimulation may clarify the mechanisms behind normal bone adaptation to mechanical loading.We have been using intracellular calcium([Ca2+]i)as a ubiquitous real-time signaling indicator for studying mechanotransduction in osteocytic network

M-LFM:a multi-level fusion modeling method for shape−performance integrated digital twin of complex structure

As a virtual representation of a specific physical asset,the digital twin has great potential for realizing the life cycle maintenance management of a dynamic system.Nevertheless,the dynamic stress concentration is generated since the state of the dynamic system changes over time.This generation of dynamic stress concentration has hindered the exploitation of the digital twin to reflect the dynamic behaviors of systems in practical engineering applications.In this context,this paper is interested in achieving real-time performance prediction of dynamic systems by developing a new digital twin framework that includes simulation data,measuring data,multi-level fusion modeling(M-LFM),visualization techniques,and fatigue analysis.To leverage its capacity,the M-LFM method combines the advantages of different surrogate models and integrates simulation and measured data,which can improve the prediction accuracy of dynamic stress concentration.A telescopic boom crane is used as an example to verify the proposed framework for stress prediction and fatigue analysis of the complex dynamic system.The results show that the M-LFM method has better performance in the computational efficiency and calculation accuracy of the stress prediction compared with the polynomial response surface method and the kriging method.In other words,the proposed framework can leverage the advantages of digital twins in a dynamic system:damage monitoring,safety assessment,and other aspects and then promote the development of digital twins in industrial fields.

Towards a shape-performance integrated digital twin for lumbar spine analysis[version 1;peer review:1 approved,1 not approved]

Background:With significant advancement and demand for digital transformation,the digital twin has been gaining increasing attention as it is capable of establishing real-time mapping between physical space and virtual space.In this work,a shape-performance integrated digital twin solution is presented to predict the real-time biomechanics of the lumbar spine during human movement.Methods:A finite element model(FEM)of the lumbar spine was firstly developed using computed tomography(CT)and constrained by the body movement which was calculated by the inverse kinematics algorithm.The Gaussian process regression was utilized to train the predicted results and create the digital twin of the lumbar spine in real-time.Finally,a three-dimensional virtual reality system was developed using Unity3D to display and record the real-time biomechanics performance of the lumbar spine during body movement.Results:The evaluation results presented an agreement(R-squared>0.8)between the real-time prediction from digital twin and offline FEM prediction.Conclusions:This approach provides an effective method of real-time planning and warning in spine rehabilitation.