Molecular & Cellular Biomechanics最新文献

{"title":"The Influence of Drag on Nonlinear Oscillatory Flow through Concentric Annulus","authors":"B Umadevi, C. V. Vinay, P. A. Dinesh","doi":"10.32604/mcb.2021.015605","DOIUrl":"https://doi.org/10.32604/mcb.2021.015605","url":null,"abstract":"A mathematical model has been developed to study the effect of particle drag parameter and frequency parameter on velocity and pressure gradient in nonlinear oscillatory two phase flow. The main purpose is to apply the model to study the combined effect of introduction of the catheter and elastic properties of the arterial wall on the pulsatile nature of the blood flow. We model the artery as an isotropic thin walled elastic tube and the catheter as a coaxial flexible tube. Blood is modeled as an incompressible particulate viscous Newtonian fluid. Perturbation technique has been applied to find the approximations for velocity and pressure gradient up to second order. Numerical solutions are investigated with graphical presentations to understand the effects of drag parameter, frequency parameter and phase angle on velocity along radial direction and pressure gradient along axial directions. As the drag parameter increases, mean pressure gradient and mean velocity will be decreased. As frequency parameter increases mean velocity profile bends near the outer wall. Due to elastic nature of artery wall, a thin catheter experience small oscillations and a thick catheter remains stationary inside the artery. Finally, the effect of catheterization on various physiologically important flow rate characteristics—mean velocity, mean pressure gradient are studied for a range of different catheter sizes, particle drag parameter and frequency parameters.","PeriodicalId":48719,"journal":{"name":"Molecular & Cellular Biomechanics","volume":"78 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74041595","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}

{"title":"Study on the Effect of PNF Method on the Flexibility and Strength Quality of Stretching Muscles of Shoulder Joints of Swimmers","authors":"Boqing Li, X. Bai, Yongli Zhu","doi":"10.32604/MCB.2021.014748","DOIUrl":"https://doi.org/10.32604/MCB.2021.014748","url":null,"abstract":"In the process of swimming, the shoulder joint will be damaged when the arm is stroking. To reduce the injury of shoulder joints and improve the speed of stroke, it is necessary to train the flexibility of shoulder joints. This paper briefly introduced the concept of shoulder joint and flexibility and then explained the traditional stretching training method and proprioceptive neuromuscular facilitation (PNF) stretching method. Then, taking 20 college team swimmers of Yunnan University as the subjects, the comparative experiment of the traditional and PNF stretching methods was carried out. The results showed that the shoulder rotation index of the athletes after the use of the PNF stretching method was significantly lower compared with the traditional stretching method; under the PNF stretching method, the average power and total work of shoulder joints significantly improved in the highspeed external rotation, and the performance in the 50 m freestyle also significantly improved.","PeriodicalId":48719,"journal":{"name":"Molecular & Cellular Biomechanics","volume":"86 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78952561","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}

{"title":"Biomechanical Properties of Multi-Swing and Single-Swing Rope Skipping Actions","authors":"Yiran Tian","doi":"10.32604/MCB.2021.014394","DOIUrl":"https://doi.org/10.32604/MCB.2021.014394","url":null,"abstract":"Rope skipping is popular as it is easy to learn; thus, it has developed into a competitive sport. The research on the biomechanical properties of rope skipping can effectively improve training efficiency and reduce injury probability. This paper briefly introduced the characteristics of single-swing and multi-swing techniques in competitive rope skipping, selected ten second-grade athletes as the subjects to test the single-swing and triple-swing rope skipping, and tested the biomechanical properties in the process of rope skipping. The results showed that the variation range of the lower limb joint angle in the triple-swing rope skipping was larger than that in the single-swing rope skipping in the stage of thrusting against the ground and the hanging stage and smaller in the buffering stage. The maximum ground reaction force, the maximum vertical displacement, the vertical velocity at the moment of leaving the ground, and the vertical velocity at the moment of landing in triple-swing rope skipping were significantly higher than those in the process of single-swing rope skipping. In conclusion, to ensure the success of the triple-swing rope skipping, the lower limbs need to exert a larger acting force on the ground to obtain larger counter-acting force to extend the hanging time and ensure three circles.","PeriodicalId":48719,"journal":{"name":"Molecular & Cellular Biomechanics","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88859318","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}

{"title":"Cyclic Stretch Induces Inflammatory Cytokines via the Oxidative Stress and NF-ΚB Pathways Activation in Human Keratoconic Fibroblasts","authors":"Xiao-na Li, Sijia Wang, Jie Song, Yi-Xian Qin, Jizhong Yang, Rui He, Weiyi Chen","doi":"10.32604/MCB.2021.014071","DOIUrl":"https://doi.org/10.32604/MCB.2021.014071","url":null,"abstract":"The cornea is a load-bearing tissue. Lower biomechanical properties in the local tissue of keratoconic cornea evoke mechanical stress increase. Inflammatory cytokines have been shown to be over-expressed in patients with keratoconus. However, how mechanical stimuli are involved in the production of inflammatory cytokines in keratoconus remains unclear. The objective of the study is to determine the role of mechanical stretch in the regulation of inflammatory cytokines and the underlying mechanisms in keratoconus. Human keratoconic fibroblasts (hKCFs) were subjected to 12% cyclic mechanical stretch at 0.1 Hz or in static conditions as controls. N-acetyl cysteine (NAC) and pyrrolidine dithiocarbamate and pyrrolidine dithiocarbamate (PDTC) were used to inhibit reactive oxygen species (ROS) production and NF-κB pathway respectively. ROS production was measured using 2’,7’-dichlorodihydrofluorescindiacetate probe. Conditioned media and cell lysates were collected for protein assessment. Cyclic stretch-induced a higher production of intercellular cell adhesion molecule-1 (ICAM-1), tumor necrosis factor α (TNF-α), interleukin (IL)-6, and IL-8 in hKCFs than static controls. ROS was also elevated in response to cyclic stretch. Inhibition of ROS or NF-κB attenuated stretch-induced ICAM-1, TNF-α, IL-6, and IL-8. Inhibition of stretch-induced ROS production by NAC also attenuated NF-κB activation. Our findings suggest that mechanical stretch may induce the release of inflammatory cytokines by activating oxidative stress and NF-kB pathway, and ROS may positively control NF-κB signaling. Over-expression of inflammatory cytokines induced by mechanical stretch may play a role in progression of keratoconus.","PeriodicalId":48719,"journal":{"name":"Molecular & Cellular Biomechanics","volume":"65 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86094445","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}

{"title":"Numerical Simulation of Bone Plate with Fatigue Crack and Investigation of Attraction Hole for Retarding Crack Growth","authors":"Zhonghang Zhao, A. Ji, Changsheng Chen","doi":"10.32604/mcb.2021.016238","DOIUrl":"https://doi.org/10.32604/mcb.2021.016238","url":null,"abstract":"Premature fracture of the bone plate caused by fatigue crack is the main failure mode in treating femoral shaft fracture. In order to improve the durability of the plate, this study proposed a crack attraction hole (CAH) to retard the crack propagation based on the fracture mechanics. In this paper, a numerical model of the femoral fracture internal fixation system was constructed, in which the femur was developed using a validated simplified model. First, the fatigue crack initiation location was defined at the stress concentration through static analysis. Next, with the joint simulation method of Franc3D and ABAQUS, the fatigue crack path in the bone plate was predicted. Meanwhile, the Paris parameters of Ti-6Al-4V obtained through experiments were encoded into Franc3D to calculate the crack propagation life. Finally, we considered the influence of CAH designs with different relative vertical distances (2.0, 3.0, and 4.0 mm) and diameters (1.5, 2.0, and 2.5 mm) on the crack propagation path and life of the bone plate. Additionally, the effects of all CAH configurations on the biomechanical performance of the bone plate fixation system were evaluated. The results indicated that the fatigue crack growth path in the bone plate is comparable to a straight line, and the crack growth rate significantly increases when the crack tip reaches the outer boundary of the plate. The findings suggest that the addition of CAH in the bone plate will lead to the deflection of the crack path and increase the fatigue life. Equally important, the improvement of the fatigue life was positively correlated with the diameter of CAH and negatively correlated with the relative vertical distance. In addition, the biomechanical properties of the bone plate system were slightly affected by CAH, substantiating the feasibility of this method. Finally, the comparative analysis verified that a CAH with a relative vertical distance of 3 mm and a diameter of 2 mm exhibited superior improvement in the comprehensive performance on the bone plate.","PeriodicalId":48719,"journal":{"name":"Molecular & Cellular Biomechanics","volume":"31 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78305161","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}

{"title":"Certain Investigations on Melanoma Detection Using Non-Subsampled Bendlet Transform with Different Classifiers","authors":"S. Poovizhi, T. R. Ganesh Babu, R. Praveena","doi":"10.32604/mcb.2021.017984","DOIUrl":"https://doi.org/10.32604/mcb.2021.017984","url":null,"abstract":"Skin is the largest organ and outer enclosure of the integumentary system that protects the human body from pathogens. Among various cancers in the world, skin cancer is one of the most commonly diagnosed cancer which can be either melanoma or non-melanoma. Melanoma cancers are very fatal compared with non-melanoma cancers but the chances of survival rate are high when diagnosed and treated earlier. The main aim of this work is to analyze and investigate the performance of Non-Subsampled Bendlet Transform (NSBT) on various classifiers for detecting melanoma from dermoscopic images. NSBT is a multiscale and multidirectional transform based on second order shearlet system which precisely classifies the curvature over other directional representation systems. Here two-phase classification is employed using k-Nearest Neighbour (kNN), Naive Bayes (NB), Decision Trees (DT) and Support Vector Machines (SVM). The first phase classification is used to classify the images of PH2 database into normal and abnormal images and the second phase classification classifies the abnormal images into benign and malignant. Experimental result shows the improvement in classification accuracy, sensitivity and specificity compared with the state of art methods.","PeriodicalId":48719,"journal":{"name":"Molecular & Cellular Biomechanics","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90459289","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}

{"title":"Study of Hepatocytes Polyploidization Peculiarities in Cholestatic Liver of Adult Rats","authors":"S. Kiparoidze, N. Karumidze, E. Bakuradze, I. Modebadze, L. Rusishvili, D. Kordzaia, D. Dzidziguri","doi":"10.32604/mcb.2021.015596","DOIUrl":"https://doi.org/10.32604/mcb.2021.015596","url":null,"abstract":"According to the literature, different mechanisms and kinetics proceeding of regenerative growth has been established using the basic models of liver regeneration (after resection or chemically induced). Hence, in order to determine general regularities of the adaptive-compensatory processes in various pathological conditions, the processes taking place in the cholestatic liver of adult white rats during the first four days after common bile duct ligation have been studied. It has been shown that in cholestatic liver, compensatory-adaptive processes take place with different kinetics compared to those after resection. In particular, in response to the increased functional load caused by destructive processes during cholestasis, the liver, at an early stage, responds by simple division of high ploidy (binuclear tetraploid) cells and further provides their quantitative increase. The difference between the processes taking place in cholestatic and resected liver is more expressed on the third and fourth day after common bile duct ligation. In particular, 4c cells are still highest in cholestatic liver, while all ploidy cells are present in equal numbers in the regenerated liver after resection. This fact of compensatory growth characteristic for reparative regeneration was not detected in cholestatic liver at the mentioned date.","PeriodicalId":48719,"journal":{"name":"Molecular & Cellular Biomechanics","volume":"6 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79238112","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}

{"title":"Study on the Effect of Shoulder Training on the Mechanics of Tennis Serve Speed through Video Analysis","authors":"Wei Jiang, Gang He","doi":"10.32604/mcb.2021.017050","DOIUrl":"https://doi.org/10.32604/mcb.2021.017050","url":null,"abstract":"Tennis service is an important part of winning a match. This study analyzed the mechanics of tennis serving speed and divided ten tennis players into two groups. One group carried out conventional training, while the other group carried out auxiliary training on shoulders through elastic band besides conventional training. The actions were photographed by cameras and analyzed. The results showed that the throwing height and hitting point height of the two groups improved after the experiment, and p < 0.05 in the comparison between Groups A and B; the ball deflection angle reduced after throwing, but the improvement of Group B was more significant compared to Group A (p < 0.05); the service speed and success rate also significantly improved in Group B, i. e., the performance of Group B was better (p < 0.05). The results show that shoulder training plays a positive role in improving the service speed and the video analysis method is reliable in training, which is conducive to improving the training efficiency.","PeriodicalId":48719,"journal":{"name":"Molecular & Cellular Biomechanics","volume":"16 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90384625","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}

{"title":"Effect of Mechanical Forces on the Behavior of Dental Stem Cells: A Scoping Review of In-Vitro Studies","authors":"M. Rad, Sadra Mohaghegh, Farnaz Kouhestani, S. Motamedian","doi":"10.32604/MCB.2021.015136","DOIUrl":"https://doi.org/10.32604/MCB.2021.015136","url":null,"abstract":"This article is a scoping review of the studies that assessed the effect of mechanical forces on the behavior of dental stem cells (DSCs). PubMed and Scopus searches were done for in-vitro studies evaluating the effect of tension, hydrostatic pressure (i.e., the pressure applied through an incompressible fluid), compression, simulated microgravity, and vibration on DSCs. The following factors were analyzed: osteogenic/odontogenic differentiation, proliferation, adhesion and migration. Articles were reviewed according to the Preferred Reporting Items for Systematic Reviews extension for scoping reviews (PRISMA-ScR) guideline. Included studies were evaluated based on the modified Consolidated Standards of Reporting Trials (CONSORT). A total of 18 studies published from 2008–2019 were included. Nine studies were focusing on Periodontal ligament Stem Cells (PDLSCs), eight studies on Dental Pulp Stem Cells (DPSCs) and one study on Stem Cells from Apical Papilla (SCAP). Results showed that tension, three-dimensional stress and simulated microgravity promoted the proliferation and osteogenic differentiation of PDLSCs. DPSCs proliferation increased after microgravity and tension exertion. In addition, dynamic hydrostatic pressure and compression promoted odontogenic differentiation of DPSCs. Besides, mechanical stimuli increased the osteogenic differentiation of DPSCs. One study analyzed the effect of carrier features on the response of DSCs to 3D-stress and showed that cells cultivated on scaffolds with 30% bioactive glass (BAG) had the highest osteogenic differentiation compared to other ratios of BAG. It has been shown that increasing the duration of tension (i.e., from 3 h to 24 h force application) enhanced the positive effect of force application on the osteogenic differentiation of DSCs. In conclusion, all types of mechanical forces except uniaxial tension increased the osteogenic/odontogenic differentiation of DSCs. In addition, the effect of mechanical stimulation on the proliferation of DSCs differs based on the type of stem cells and mechanical force.","PeriodicalId":48719,"journal":{"name":"Molecular & Cellular Biomechanics","volume":"37 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80085579","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}

{"title":"Surface Topography Assessments of Spine Shape Change within the Day in Healthy Male Adults","authors":"Jianming Lu, Liangliang Xiang, Huw Wiltshire","doi":"10.32604/mcb.2021.015993","DOIUrl":"https://doi.org/10.32604/mcb.2021.015993","url":null,"abstract":"Surface topography is a no-invasive, radiation-free method that can measure sufficient surface spine parameters by the structured back surface scan and a precise anatomical landmarks recognition. The purpose of the present study was to measure the spine shape parameter changes within the day via the DIERS Formetric 4D analysis system. Ten male healthy volunteers were recruited to participate in the experiment. All participants were sedentary people with the average sitting time during study or work t ≥ 8 h and without any back disease in the past six months. Data were analyzed by one-way ANOVA, which set time points within the day as variable and shape results as the dependent variable. The significant difference could be found for the trunk length VP-DM with a one-way ANOVA test of p = 0.011. There was a significant difference (p = 0.024) between time slots of 9 am and 7 pm with 95%CI (–15.83, –1.01) and MD –8.42. No significant difference statistically for the scoliosis angle and the p-value of the one-way ANOVA test is 0.715. There was no significant difference for trunk inclination VP-DM with a one-way ANOVA test of p = 0.284. Statistical analysis depicted no significant difference for the trunk imbalance VP-DM with a one-way ANOVA test of p = 0.730. Trunk length VP-DM was significantly decreased in the afternoon and evening. This may be a potential back pain risk for sedentary individuals. Regular physical activity and mild to moderate exercise are recommended to improve spinal stability and maintain spinal shape.","PeriodicalId":48719,"journal":{"name":"Molecular & Cellular Biomechanics","volume":"12 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86531156","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}