JongWon Kim^1,2, Ning Li², Ramana Pidaparti^2,*, Xianqiao Wang^2,*

Molecular & Cellular Biomechanics, Vol.15, No.3, pp. 127-141, 2018, DOI: 10.3970/mcb.2018.02669

Abstract Nonlinear microstructure of the microtubules (MTs) plays an important role in their mechanical properties. Despite the extensive efforts into the development of continuum models for microtubules, a mesoscale finite element model that can link the molecular level information to the overall performance of microtubules is still missing. The aim of this study is to develop a molecular dynamics model (MDM), finite element model (FEM) and structural mechanics beam model (SMBM) for tubulins of protofilament (PF). In MDM, the backbone atoms of α-tubulin were fixed while the backbone atoms of β-tubulin were attached to a molecular dynamics (MD) atom through a… More >

Yuxiang Huang¹, Chuliu He¹, Jiaqiu Wang², Yuehong Miao¹, Tongjin Zhu¹, Ping Zhou¹, Zhiyong Li^1,2,*

Molecular & Cellular Biomechanics, Vol.15, No.2, pp. 117-125, 2018, DOI: 10.3970/mcb.2018.02478

Abstract Intravascular optical coherence tomography (IVOCT) is becoming more and more popular in clinical diagnosis of coronary atherosclerotic. However, reading IVOCT images is of large amount of work. This article describes a method based on image feature extraction and support vector machine (SVM) to achieve semi-automatic segmentation of IVOCT images. The image features utilized in this work including light attenuation coefficients and image textures based on gray level co-occurrence matrix. Different sets of hyper-parameters and image features were tested. This method achieved an accuracy of 83% on the test images. Single class accuracy of 89% for fibrous, 79.3% for calcification and… More >

Zhedian Zhou¹, Tal Geva², Rahul H. Rathod², Alexander Tang², Chun Yang³, Kristen L. Billiar⁴, Dalin Tang^1,*,3, Pedro del Nido⁵

Molecular & Cellular Biomechanics, Vol.15, No.2, pp. 99-115, 2018, DOI: 10.3970/mcb.2018.00558

Abstract Patients with repaired Tetralogy of Fallot (ToF), a congenital heart defect which includes a ventricular septal defect and severe right ventricular outflow obstruction, account for the majority of cases with late onset right ventricle (RV) failure. The current surgical approach, which includes pulmonary valve replacement/insertion (PVR), has yielded mixed results. A computational parametric study using 7 patient-specific RV/LV models based on cardiac magnetic resonance (CMR) data as "virtual surgery" was performed to investigate the impact of patch size, RV remodeling and tissue regeneration in PVR surgery design on RV cardiac functions. Two patch sizes, three degrees of scar trimming (RV… More >

Lilan Gao^1,2,*, Qingxian Yuan^1,2, Ruixin Li^3,*, Lei Chen^1,2, Chunqiu Zhang^1,2, Xizheng Zhang^1,2

Molecular & Cellular Biomechanics, Vol.15, No.2, pp. 85-98, 2018, DOI: 10.3970/mcb.2018.00329

Abstract Silk fibroin-typeⅡcollagen scaffold was made by 3D printing technique and freeze-drying method, and its mechanical properties were studied by experiments and theoretical prediction. The results show that the three-dimensional silk fibroin-typeⅡ collagen scaffold has good porosity and water absorption, which is (89.3%+3.26%) and (824.09%+93.05%), respectively. With the given strain value, the stress of scaffold decreases rapidly firstly and then tends to be stable during the stress relaxation. Both initial and instantaneous stresses increase with increase of applied strain value. The creep strains of scaffold with different stress levels show the two stages: the rapidly increasing stage and the second stable… More >

Ranu Gupta^1,3,*, Rahul Pachauri^2,3, Ashutosh Kumar Singh^1,4

Molecular & Cellular Biomechanics, Vol.15, No.2, pp. 63-83, 2018, DOI: 10.3970/mcb.2018.00114

Abstract Various chaos-based image encryption schemes have been proposed in last few years. The proposed image encryption method uses chaotic map. The encryption is done by using 256 bit long external secret key. The initial condition for the chaotic mapping is evaluated by the use of external secret key along with the mapping function. Besides that, the proposed method is made more robust by applying multiple operations to the pixels of the image depending on the outcome of the calculation of the logistic map. Moreover, block shuffling of the image and modifying the secret key after encryption of each row is… More >

Molecular & Cellular Biomechanics, Vol.15, No.1, pp. 51-61, 2018, DOI:10.3970/mcb.2018.015.051

Abstract Tracheal stenosis is a common respiratory disease and is usually treated by stent implantation. However, the implanted stent often causes excessive hyperplasia of trachea granulation tissue, leading to the restenosis. Although surgical removal or chemical suppression can be used to alleviate the restenosis, the efficacy is limited. Thus, restenosis remains a thorny complication. We investigated this issue from the perspective of the “tress-growth”relationship. Firstly, the lower airway of 5 experimental dogs were CT-scanned to reconstruct the 3D numerical models; secondly, the implantations of the Nitinol alloy stents were numerically simulated; thirdly, 45 days after the stenting, the dogs were evaluated… More >

Molecular & Cellular Biomechanics, Vol.15, No.1, pp. 21-36, 2018, DOI:10.3970/mcb.2018.015.021

Abstract Dendritic cells (DCs) are the most potent professional antigen presenting cells as now known, which play critical roles in the initiation, programming and regulation of the immune response. Transforming growth factor-β₁ (TGF-β₁), one of the major suppressive cytokines in tumor microenvironment, can deteriorate the biomechanical characteristics and motility of mature dendritic cells (mDCs)，but the underlying molecular mechanisms are not well defined. In this study, the effects of TGF-β₁ on the motilities and T cell priming capabilities of mDCs as well as the molecular regulatory mechanisms were investigated. The results showed that the cytoskeleton (F-actin) organizations of mDCs were abnormally remodeled… More >

Virginia Aragon Sanabria¹, Cheng Dong^*

Molecular & Cellular Biomechanics, Vol.15, No.1, pp. 1-19, 2018, DOI:10.3970/mcb.2018.015.001

Abstract Endothelial barrier function is critical for tissue homeostasis throughout the body. Disruption of the endothelial monolayer leads to edema, vascular diseases and even cancer metastasis among other pathological conditions. Breakdown of the endothelial barrier integrity triggered by cytokines (e.g.IL-8,IL-1β) and growth factors (e.g.VEGF) is well documented. However, endothelial cells are subject to major biomechanical forces that affect their behavior. Due to their unique location at the interface between circulating blood and surrounding tissues, endothelial cells experience shear stress, strain and contraction forces. More than three decades ago, it was already appreciated that shear flow caused endothelial cells alignment in the… More >

Longjia Li^1,2, Tianbao Qian^2,3, Fei Hang^{1, 2, *}

Molecular & Cellular Biomechanics, Vol.14, No.4, pp. 221-234, 2017, DOI:10.3970/mcb.2017.014.221

Abstract Bone is an important natural hierarchical biomaterial which supports human body and protect organs. Its mechanical property has been researched extensively. In this experimental work, 3D microscope and scanning electron microscope (SEM) were used to research crack expansion on bovine femur cortical bone transverse section. Softwares such as image J and Photoshop were used in image and data analyses. Our results suggested that the interface energy of extending through osteons is smaller than the interface energy of extending along cement lines. Cracks are more likely to extend through osteons. Further investigations are needed to reduce errors and validate our findings. More >

Yang Li¹, Xiuxian Liu², Zhiyong Li^2,*, Jiayi Tong¹, Yi Feng¹, Genshan Ma¹, Chengxing Shen³, Naifeng Liu¹

Molecular & Cellular Biomechanics, Vol.14, No.4, pp. 213-229, 2017, DOI:10.3970/mcb.2017.014.213

Abstract Coronary tortuosity is a common angiographic finding, but the hemodynamic significance of coronary tortuosity is largely unknown. The impact of coronary tortuosity on coronary pressure and wall shear stress is still unclear. We addressed this issue in the present experimental study. A distorted tube model connected to heart pumping machine was established to simulate the coronary circulation. The pressure of each point was measured with a coronary pressure guidewire. Influence of tortuosity angle and tortuosity number on local pressure was measured. Wall shear stress was calculated accordingly to the pressure of each point. Pressure distribution in this system was affected… More >