Fluoroscopy is a radiographic procedure for evaluating esophageal disorders such as achalasia, dysphasia and gastroesophageal reflux disease. It performs dynamic imaging of the swallowing process and provides anatomical detail and a qualitative idea of how well swallowed fluid is transported through the esophagus. In this work, we present a method called mechanics informed fluoroscopy (FluoroMech)

It is essential to study the viral droplet’s uptake in the human respiratory system to better control, prevent, and treat diseases. Micro-droplets can easily pass through ordinary respiratory masks. Therefore, the SARS-COV-2 transmit easily in conversation with a regular mask with 'silent spreaders' in the most physiological way of breathing through the nose, indoor and at rest condition. The results

Atherosclerosis is initiated by endothelial injury that is related to abnormal values of hemodynamic parameters such as wall shear stress (WSS), oscillatory shear index (OSI) and stress phase angle (SPA), which are more common in arterial bifurcations due to the complex structure. An experimental model of human carotid bifurcation with accurate geometrical and mechanical features was set up, and using

Pressure ulcers are localized sites of tissue damage which form due to the continuous exposure of skin and underlying soft tissues to sustained mechanical loading, by bodyweight forces or because a body site is in prolonged contact with an interfacing object. The latter is the common cause for the specific sub-class of pressure ulcers termed ‘medical device-related pressure ulcers’, where the injury

The abdominal aorta is the largest artery in the abdominal cavity that supplies blood flows to vital organs through the complex visceral arterial branches, including the celiac trunk (the liver, stomach, spleen, etc.), the renal arteries (the kidneys) and the superior and inferior mesenteric arteries (the small and large intestine, pancreas, etc.). An accurate simulation of blood flows in this network

Precision medicine is a new frontier in healthcare that uses scientific methods to customize medical treatment to the individual genes, anatomy, physiology, and lifestyle of each person. In cardiovascular health, precision medicine has emerged as a promising paradigm to enable cost-effective solutions that improve quality of life and reduce mortality rates. However, the exact role in precision medicine

The present study investigates the layer-specific mechanical behavior of human skin. Motivated by skin’s histology, a biphasic model is proposed which differentiates between epidermis, papillary and reticular dermis, and hypodermis. Inverse analysis of ex vivo tensile and in vivo suction experiments yields mechanical parameters for each layer and predicts a stiff reticular dermis and successively softer

The present study has sought to investigate the fluid characteristic and mechanical properties of trabecular bone using fluid–structure interaction (FSI) approach under different trabecular bone orientations. This method imposed on trabecular bone structure at both longitudinal and transverse orientations to identify effects on shear stress, permeability, stiffness and stress regarded to the trabeculae

Probing mechanical properties of cells has been identified as a means to infer information on their current state, e.g. with respect to diseases or differentiation. Oocytes have gained particular interest, since mechanical parameters are considered potential indicators of the success of in vitro fertilisation procedures. Established tests provide the structural response of the oocyte resulting from

In the last decade, many computational models have been developed to describe the transport of drug eluted from stents and the subsequent uptake into arterial tissue. Each of these models has its own set of limitations: for example, models typically employ simplified stent and arterial geometries, some models assume a homogeneous arterial wall, and others neglect the influence of blood flow and plasma

Microfluidic devices, such as the tumor-on-a-chip (ToC), allow for the delivery of multiple drugs as desired for various therapies such as cancer treatment. Due to the complexity involved, visualizing, and gaining knowledge of the performance of such devices through experimentation alone is difficult if not impossible. In this paper, we performed a numerical simulation study on ToC performance, which

New treatments for bone diseases require testing in animal models before clinical translation, and the mouse tibia is among the most common models. In vivo micro-Computed Tomography (microCT)-based micro-Finite Element (microFE) models can be used for predicting the bone strength non-invasively, after proper validation against experimental data. Different modelling techniques can be used to estimate

Stress fibers (SFs) in cells transmit external forces to cell nuclei, altering the DNA structure, gene expression, and cell activity. To determine whether SFs are involved in mechanosignal transduction upon intraluminal pressure, this study investigated the SF direction in smooth muscle cells (SMCs) in aortic tissue and strain in the SF direction. Aortic tissues were fixed under physiological pressure

The eye’s accommodative mechanism changes optical power for near vision. In accommodation, ciliary muscle excursion relieves lens tension, allowing it to return to its more convex shape. Lens deformation alters its refractive properties, but the mechanics of ciliary muscle actions are difficult to intuit due to the complex architecture of the tissues involved. The muscle itself comprises three sections

Congenital heart defects (CHDs) are abnormalities in the heart structure present at birth. One important condition is hypoplastic left heart syndrome (HLHS) where severely underdeveloped left ventricle (LV) cannot support systemic circulation. HLHS usually initiates as localized tissue malformations with no underlying genetic cause, suggesting that disturbed hemodynamics contribute to the embryonic

To study the ostrich (Struthio camelus) foot sole with an irregular surface and papillae, we designed a multi-angle device to measure its friction properties on sand. The observed macro- and micro-structures of the ostrich foot sole intensified friction by tightly gripping sand particles. The sliding friction of the ostrich foot on a single-layer sand board increased with the enlarging particle size

Aortic dissections progress, in part, by delamination of the wall. Previous experiments on cut-open segments of aorta demonstrated that fluid injected within the wall delaminates the aorta in two distinct modes: stepwise progressive tearing in the abdominal aorta and a more prevalent sudden mode of tearing in the thoracic aorta that can also manifest in other regions. A microstructural understanding

Correction to: Biomechanics and Modeling in Mechanobiology.

Magnetic drug delivery known as smart technique in medicine is basically according to combining the drug inside capsules with the magnetic property or attaching the drug with magnetic surfaces at the micro- and nanoscale. In the present study, magnetic drug delivery in the aortic artery has been investigated. To approach the more realistic problem conditions of blood flow rheology, the effect of parameters

Smooth muscle cells (SMCs) usually express a contractile phenotype in the healthy aorta. However, aortic SMCs have the ability to undergo profound changes in phenotype in response to changes in their extracellular environment, as occurs in ascending thoracic aortic aneurysms (ATAA). Accordingly, there is a pressing need to quantify the mechanobiological effects of these changes at single cell level

The spreading of infectious diseases including COVID-19 depends on human interactions. In an environment where behavioral patterns and physical contacts are constantly evolving according to new governmental regulations, measuring these interactions is a major challenge. Mobility has emerged as an indicator for human activity and, implicitly, for human interactions. Here, we study the coupling between

The active response of cells to mechanical cues due to their interaction with the environment has been of increasing interest, since it is involved in many physiological phenomena, pathologies, and in tissue engineering. In particular, several experiments have shown that, if a substrate with overlying cells is cyclically stretched, they will reorient to reach a well-defined angle between their major

A pathologically formed blood clot or thrombus is central to major cardiovascular diseases like heart attack and stroke. Detailed quantitative evaluation of flow and flow-mediated transport processes in the thrombus neighborhood within large artery hemodynamics is crucial for understanding disease progression and assessing treatment efficacy. This, however, remains a challenging task owing to the complexity

The monitoring of the ciliated walls in the uterine tube has supreme importance in enhancing the sperm to reach the egg (capacitation processes), and at peristaltic ciliary flow has a more favorable residual time along the canal when compared to the peristaltic flow. Based on the importance of this study, a mathematical simulation of this process has been carried out by studying the behavior of a non-Newtonian

Previous studies have shown that the rupture properties of an ascending thoracic aortic aneurysm (ATAA) are strongly correlated with the pre-rupture response features. In this work, we present a two-step machine learning method to predict where the rupture is likely to occur in ATAA and what safety reserve the structure may have. The study was carried out using ATAA specimens from 15 patients who underwent

Computational modelling is an invaluable tool for investigating features of human locomotion and motor control which cannot be measured except through invasive techniques. Recent research has focussed on creating personalised musculoskeletal models using population-based morphing or directly from medical imaging. Although progress has been made, robust definition of two critical model parameters remains

Turbulent-like hemodynamics with prominent cycle-to-cycle flow variations have received increased attention as a potential stimulus for cardiovascular diseases. These turbulent conditions are typically evaluated in a statistical sense from single scalars extracted from ensemble-averaged tensors (such as the Reynolds stress tensor), limiting the amount of information that can be used for physical interpretations

In order for computational fluid dynamics to provide quantitative parameters to aid in the clinical assessment of type B aortic dissection, the results must accurately mimic the hemodynamic environment within the aorta. The choice of inlet velocity profile (IVP) therefore is crucial; however, idealised profiles are often adopted, and the effect of IVP on hemodynamics in a dissected aorta is unclear

An exponential rise in patient data provides an excellent opportunity to improve the existing health care infrastructure. In the present work, a method to enable cardiovascular digital twin is proposed using inverse analysis. Conventionally, accurate analytical solutions for inverse analysis in linear problems have been proposed and used. However, these methods fail or are not efficient for nonlinear

The interphase joining tendon to bone plays the crucial role of integrating soft to hard tissues, by effectively transferring stresses across two tissues displaying a mismatch in mechanical properties of nearly two orders of magnitude. The outstanding mechanical properties of this interphase are attributed to its complex hierarchical structure, especially by means of competing gradients in mineral

The S-shaped curvature of the spine has been hypothesized as the underlying mechanical cause of adolescent idiopathic scoliosis. In earlier work, we proposed a reduced-order model in which the spine was viewed as an S-shaped elastic rod under torsion and bending. Here, we simulate the deformation of S-shaped rods of a wide range of curvatures and inflection points under a fixed mechanical loading.

Finite element head (FE) models are important numerical tools to study head injuries and develop protection systems. The generation of anatomically accurate and subject-specific head models with conforming hexahedral meshes remains a significant challenge. The focus of this study is to present two developmental works: first, an anatomically detailed FE head model with conforming hexahedral meshes that

Quantification of lumbar spine load transfer is important for understanding low back pain, especially among persons with a lower limb amputation. Computational modeling provides a helpful solution for obtaining estimates of in vivo loads. A multiscale model was constructed by combining musculoskeletal and finite element (FE) models of the lumbar spine to determine tissue loading during daily activities

Mechanical behaviour of pre-stressed fibre-reinforced composites is modelled in a geometrically exact setting. A general approach which includes two different reference configurations is employed: one configuration corresponds to the load-free state of the structure and another one to the stress-free state of each material particle. The applicability of the approach is demonstrated in terms of a viscoelastic

The adolescent idiopathic scoliosis (AIS) is a 3D deformity of the spine whose origin is unknown and clinical evolution unpredictable. In this work, a mixed theoretical and numerical approach based on energetic considerations is proposed to study the global spine deformations. The introduced mechanical model aims at overcoming the limitations of computational cost and high variability in physical parameters

Bone plates are used to treat bone fractures by stabilizing the fracture site and allowing treatments to take place. Mechanical properties of the applied bone plate determine the stability of the fracture site and affect the endochondral ossification process and the healing performance. In recent years, biodegradable bone plates have been used in demand for the elimination of a second surgery to remove

Growth and remodeling in the heart is driven by a combination of mechanical and hormonal signals that produce different patterns of growth in response to exercise, pregnancy, and various pathologies. In particular, increases in afterload lead to concentric hypertrophy, a thickening of the walls that increases the contractile ability of the heart while reducing wall stress. In the current study, we

The nucleus pulposus (NP) in the intervertebral disk (IVD) depends on diffusive fluid transport for nutrients through the cartilage endplate (CEP). Disruption in fluid exchange of the NP is considered a cause of IVD degeneration. Furthermore, CEP calcification and sclerosis are hypothesized to restrict fluid flow between the NP and CEP by decreasing permeability and porosity of the CEP matrix. We performed

Lumbar spine biomechanics during the forward-bending of the upper body (flexion) are well investigated by both in vivo and in vitro experiments. In both cases, the experimentally observed relative motion of vertebral bodies can be used to calculate the instantaneous center of rotation (ICR). The timely evolution of the ICR, the centrode, is widely utilized for validating computer models and is thought

The scar is a predominant outcome of adult mammalian wound healing despite being associated with partial function loss. Here in this paper, we have described the structure of a full-thickness normal scar as a “di-fork” with dual biomechanical compartments using in vivo and ex vivo experiments. We used structural mechanics simulations to model the deformation fields computationally and stress distribution

Atherosclerotic plaque in the femoral is the leading cause of peripheral artery disease (PAD), the worse consequence of which may lead to ulceration and gangrene of the feet. Numerical studies on fluid-structure interactions (FSI) of atherosclerotic femoral arteries enable quantitative analysis of biomechanical features in arteries. This study aims to investigate the hemodynamic performance and its

An essential prerequisite for the efficient biomechanical tailoring of crops is to accurately relate mechanical behavior to compositional and morphological properties across different length scales. In this article, we develop a multiscale approach to predict macroscale stiffness and strength properties of crop stem materials from their hierarchical microstructure. We first discuss the experimental

Human embryonic stem cells (hESCs) can differentiate to three germ layers within biochemical and biomechanical niches. The complicated mechanical environments in vivo could have diverse effects on the fate decision and biological functions of hESCs. To globally screen mechanosensitive molecules, three typical types of mechanical stimuli, i.e., tensile stretch, shear flow, and mechanical compression

The adhesion of a circulating tumor cell (CTC) in a three-dimensional curved microvessel was numerically investigated. Simulations were first performed to characterize the differences in the dynamics and adhesion of a CTC in the straight and curved vessels. After that, a parametric study was performed to investigate the effects of the applied driven force density f (or the flow Reynolds number Re)

Atrioventricular heart valves (AHVs) regulate the unidirectional flow of blood through the heart by opening and closing of the leaflets, which are supported in their functions by the chordae tendineae (CT). The leaflets and CT are primarily composed of collagen fibers that act as the load-bearing component of the tissue microstructures. At the CT-leaflet insertion, the collagen fiber architecture is

Serious wounds, both chronic and acute (e.g., surgical), are among the most common, expensive and difficult-to-treat health problems. Negative pressure wound therapy (NPWT) is considered a mainstream procedure for treating both wound types. Soft tissue deformation stimuli are the crux of NPWT, enhancing cell proliferation and migration from peri-wound tissues which contributes to healing. We developed

The stiffness of the cellular environment controls malignant cell phenotype and proliferation. However, the effect of viscous dissipation on these parameters has not yet been investigated, in part due to the lack of in vitro cell substrates reproducing the mechanical properties of normal tissues and tumors. In this article, we use a newly reported viscoelastic polyacrylamide gel cell substrate, and

Actin stress fibers (SFs), a contractile apparatus in nonmuscle cells, possess a contractile unit that is apparently similar to the sarcomere of myofibrils in muscles. The function of SFs has thus often been addressed based on well-characterized properties of muscles. However, unlike the fixed number of myosin molecules in myofibrils, the number of nonmuscle myosin II (NMII) within the contractile

Amoeboid cells often migrate using pseudopods, which are membrane protrusions that grow, bifurcate, and retract dynamically, resulting in a net cell displacement. Many cells within the human body, such as immune cells, epithelial cells, and even metastatic cancer cells, can migrate using the amoeboid phenotype. Amoeboid motility is a complex and multiscale process, where cell deformation, biochemistry

Ischemic mitral regurgitation (IMR), a frequent complication of myocardial infarction, is characterized by regurgitation of blood from the left ventricle back into the left atrium. Physical interventions via surgery or less-invasive techniques are the only available therapies for IMR, with valve repair via undersized ring annuloplasty (URA) generally preferred over valve replacement. However, recurrence

Vascular stenting is a common intervention for the treatment for atherosclerotic plaques. However, stenting still has a significant rate of restenosis caused by intimal hyperplasia formation. In this study, we evaluate whether stent overexpansion leads to Vasa Vasorum (VV) compression, which may contribute to vascular wall hypoxia and restenosis. An idealized multilayered fibroatheroma model including

The compliance of the proximal aortic wall is a major determinant of cardiac afterload. Aortic compliance is often estimated based on cross-sectional area changes over the pulse pressure, under the assumption of a negligible longitudinal stretch during the pulse. However, the proximal aorta is subjected to significant axial stretch during cardiac contraction. In the present study, we sought to evaluate

Revealing the mechanisms underlying the intracellular calcium responses in vascular endothelial cells (VECs) induced by mechanical stimuli contributes to a better understanding for vascular diseases, including hypertension, atherosclerosis, and aneurysm. Combining with experimental measurement and Computational Fluid Dynamics simulation, we developed a mechanobiological model to investigate the intracellular

The artery relies on interlamellar structural components, mainly elastin and collagen fibers, for maintaining its integrity and resisting dissection propagation. In this study, the contribution of arterial elastin and collagen fibers to interlamellar bonding was studied through mechanical testing, multiphoton imaging and finite element modeling. Steady-state peeling experiments were performed on porcine

Performing physiologically relevant simulations of the beating heart in clinical context requires to develop detailed models of the microscale force generation process. These models, however, may reveal difficult to implement in practice due to their high computational costs and complex calibration. We propose a hierarchy of three interconnected muscle contraction models—from the more refined to the

Many biomedical, orthopaedic, and industrial applications are emerging that will benefit from personalized neuromusculoskeletal models. Applications include refined diagnostics, prediction of treatment trajectories for neuromusculoskeletal diseases, in silico design, development, and testing of medical implants, and human–machine interfaces to support assistive technologies. This review proposes how

Vesiculation is a ubiquitous process undergone by most cell types and serves a variety of vital cell functions; vesiculation from erythrocytes, in particular, is a well-known example and constitutes a self-protection mechanism against premature clearance, inter alia. Herein, we explore a paradigm that red blood cell derived vesicles may form within the microvascular, in intense shear flow, where cells

A continuous model for the peristaltic locomotion of compressible and incompressible rod-like bodies is presented. Using Green and Naghdi’s theory of a directed rod, incompressibility is enforced as an internal constraint. A discussion on muscle actuation models for a single continuum is included. The resulting theory is demonstrated in a simulation of a soft-robotic device. In addition, a calibration

We propose a mechanical model of generation of vitreoretinal tractions in the presence of posterior vitreous detachment (PVD). PVD is a common occurrence with aging, and it consists in the separation of the vitreous body from the retina at the back pole of the eye, due to progressive shrinking of the vitreous gel. During this separation process, vitreoretinal tractions are generated at regions of high