Pub Date : 2021-01-01DOI: 10.32604/MCB.2021.012598
Y. Zhao, Parham Vatankhah, Tiffany Goh, Jiaqiu Wang, Xuanyi Chen, M. N. Kashani, Keke Zheng, Zhiyong Li, L. Ju
Platelet aggregation plays a central role in pathological thrombosis, preventing healthy physiological blood fl ow within the circulatory system. For decades, it was believed that platelet aggregation was primarily driven by solu-ble agonists such as thrombin, adenosine diphosphate and thromboxane A2. However, recent experimental fi nd-ings have unveiled an intriguing but complementary biomechanical mechanism — the shear rate gradients generated from fl ow disturbance occurring at sites of blood vessel narrowing, otherwise known as stenosis, may rapidly trigger platelet recruitment and subsequent aggregation. In our Nature Materials 2019 paper [1], we employed micro fl uidic devices which incorporated micro-scale stenoses to elucidate the molecular insights underlying the prothrombotic effect of blood fl ow disturbance. Nevertheless, the rheological mechanisms associated with this stenotic micro fl uidic device are poorly characterized. To this end, we developed a computational fl uid dynamics (CFD) simulation approach to systematically analyze the hemodynamic in fl uence of bulk fl ow mechanics and fl ow medium. Grid sensitivity studies were performed to ensure accurate and reliable results. Interestingly, the peak shear rate was signi fi cantly reduced with the device thickness, suggesting that fabrication of micro fl uidic devices should retain thicknesses greater than 50 µm to avoid unexpected hemodynamic aberra-tion, despite thicker devices raising the cost of materials and processing time of photolithography. Overall, as many groups in the fi eld have designed micro fl uidic devices to recapitulate the effect of shear rate gradients and investigate platelet aggregation, our numerical simulation study serves as a guideline for rigorous design and fabrication of micro fl uidic thrombosis models. blood fl ow rendering was colored by shear rate at constant viscosity. Note the shear rate maxima occurs at the stenosis apex and near the wall while the center forms a low shear pocket. (B and F) Peak shear rate γ max linearly correlates with input bulk shear rate γ 0 for both eccentric and concentric stenoses respectively. Note the concentric stenosis geometry demonstrates better linearity. The shear rate γ (C and G) and shear rate gradient γ ’ (D and H) distribution were analyzed along a sample streamline 1µm above stenosis apex spanning the shear acceleration ( x = − 100 – 0 µm) and deceleration ( x = 0 – 100 µm) zones. Note the γ and γ ’ present equal-space increment in regard to γ 0 . The γ max is located at x = 0 µm while the γ ’ max is located at x = − 5 µm
{"title":"Computational Fluid Dynamics Simulations at Micro-Scale Stenosis for Microfluidic Thrombosis Model Characterization","authors":"Y. Zhao, Parham Vatankhah, Tiffany Goh, Jiaqiu Wang, Xuanyi Chen, M. N. Kashani, Keke Zheng, Zhiyong Li, L. Ju","doi":"10.32604/MCB.2021.012598","DOIUrl":"https://doi.org/10.32604/MCB.2021.012598","url":null,"abstract":"Platelet aggregation plays a central role in pathological thrombosis, preventing healthy physiological blood fl ow within the circulatory system. For decades, it was believed that platelet aggregation was primarily driven by solu-ble agonists such as thrombin, adenosine diphosphate and thromboxane A2. However, recent experimental fi nd-ings have unveiled an intriguing but complementary biomechanical mechanism — the shear rate gradients generated from fl ow disturbance occurring at sites of blood vessel narrowing, otherwise known as stenosis, may rapidly trigger platelet recruitment and subsequent aggregation. In our Nature Materials 2019 paper [1], we employed micro fl uidic devices which incorporated micro-scale stenoses to elucidate the molecular insights underlying the prothrombotic effect of blood fl ow disturbance. Nevertheless, the rheological mechanisms associated with this stenotic micro fl uidic device are poorly characterized. To this end, we developed a computational fl uid dynamics (CFD) simulation approach to systematically analyze the hemodynamic in fl uence of bulk fl ow mechanics and fl ow medium. Grid sensitivity studies were performed to ensure accurate and reliable results. Interestingly, the peak shear rate was signi fi cantly reduced with the device thickness, suggesting that fabrication of micro fl uidic devices should retain thicknesses greater than 50 µm to avoid unexpected hemodynamic aberra-tion, despite thicker devices raising the cost of materials and processing time of photolithography. Overall, as many groups in the fi eld have designed micro fl uidic devices to recapitulate the effect of shear rate gradients and investigate platelet aggregation, our numerical simulation study serves as a guideline for rigorous design and fabrication of micro fl uidic thrombosis models. blood fl ow rendering was colored by shear rate at constant viscosity. Note the shear rate maxima occurs at the stenosis apex and near the wall while the center forms a low shear pocket. (B and F) Peak shear rate γ max linearly correlates with input bulk shear rate γ 0 for both eccentric and concentric stenoses respectively. Note the concentric stenosis geometry demonstrates better linearity. The shear rate γ (C and G) and shear rate gradient γ ’ (D and H) distribution were analyzed along a sample streamline 1µm above stenosis apex spanning the shear acceleration ( x = − 100 – 0 µm) and deceleration ( x = 0 – 100 µm) zones. Note the γ and γ ’ present equal-space increment in regard to γ 0 . The γ max is located at x = 0 µm while the γ ’ max is located at x = − 5 µm","PeriodicalId":48719,"journal":{"name":"Molecular & Cellular Biomechanics","volume":"17 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87856612","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}
Pub Date : 2021-01-01DOI: 10.32604/MCB.2021.015453
Datao Xu, Zhenghui Lu, Siqin Shen, G. Fekete, U. Ugbolue, Yaodong Gu
Patellar tendinopathy is a clinical symptom of patellar tendons characterized by local pain in the front of the knee joint. It is common among basketball and volleyball players. Patients with patellar tendinopathy may exhibit different landing strategies during landing compared to healthy individuals. The purpose of this study was to compare the differences in lower limb joint energy dissipation (eccentric work) values for the symptomatic patellar tendinopathy (PT) athletes and no patellar tendinopathy (UPT) athletes during single-leg landing. A total of 26 (PT: 13, UPT:13) semi-professional male basketball and volleyball player’s kinetic data were collected during the landing phases. Joint work was calculated by the integral of joint power over time. In this study, the result showed that the ankle joint means energy dissipation (p < 0.001) and total energy dissipation (p < 0.001) of PT were significantly greater than UPT. Compared to the UPT athletes, the PT athletes showed smaller knee joint mean energy dissipation (p = 0.002) and contribution to total energy dissipation (p < 0.001) during the landing stance. Meanwhile, there were no differences in hip joint contribution to total energy dissipation (p = 0.523) and lower limb total energy dissipation (p = 0.127). A deeper understanding of each joint’s energy dissipation contribution ratio between UPT and PT during landing can provide clues that reveal the biomechanical mechanism of PT athletes landing. Further study should choose a larger sample size to more comprehensively reveal the energy dissipation strategy of PT during landing.
{"title":"The Differences in Lower Extremity Joints Energy Dissipation Strategy during Landing between Athletes with Symptomatic Patellar Tendinopathy (PT) and without Patellar Tendinopathy (UPT)","authors":"Datao Xu, Zhenghui Lu, Siqin Shen, G. Fekete, U. Ugbolue, Yaodong Gu","doi":"10.32604/MCB.2021.015453","DOIUrl":"https://doi.org/10.32604/MCB.2021.015453","url":null,"abstract":"Patellar tendinopathy is a clinical symptom of patellar tendons characterized by local pain in the front of the knee joint. It is common among basketball and volleyball players. Patients with patellar tendinopathy may exhibit different landing strategies during landing compared to healthy individuals. The purpose of this study was to compare the differences in lower limb joint energy dissipation (eccentric work) values for the symptomatic patellar tendinopathy (PT) athletes and no patellar tendinopathy (UPT) athletes during single-leg landing. A total of 26 (PT: 13, UPT:13) semi-professional male basketball and volleyball player’s kinetic data were collected during the landing phases. Joint work was calculated by the integral of joint power over time. In this study, the result showed that the ankle joint means energy dissipation (p < 0.001) and total energy dissipation (p < 0.001) of PT were significantly greater than UPT. Compared to the UPT athletes, the PT athletes showed smaller knee joint mean energy dissipation (p = 0.002) and contribution to total energy dissipation (p < 0.001) during the landing stance. Meanwhile, there were no differences in hip joint contribution to total energy dissipation (p = 0.523) and lower limb total energy dissipation (p = 0.127). A deeper understanding of each joint’s energy dissipation contribution ratio between UPT and PT during landing can provide clues that reveal the biomechanical mechanism of PT athletes landing. Further study should choose a larger sample size to more comprehensively reveal the energy dissipation strategy of PT during landing.","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":"82966764","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}
Pub Date : 2021-01-01DOI: 10.32604/mcb.2021.017750
F. Rahbar, Avid Farhang Fagheh, A. Khosravi, Siavash Shariatzadeh, R. Akhavan-Sigari
The protein ERp57 is a stress-responsive protein, mainly exists in the endoplasmic reticulum (ER), and a small amount in the cell membrane, cytoplasm, nucleus and mitochondria, which is involved in the signal transduction from the cell surface, the regulation process that occurs in the nucleus, and the formation of polymer protein complexes involved in DNA repair. Various degrees of ERp57 dysregulation has been observed in many types of non-communicable diseases especially in cancers. Previous studies showed that the expression of ERp57 could play a key role in occurrence and development of cancers such as breast cancer, gastric cancer, ovarian cancer, etc.; in addition, it has been suggested to play a pivotal role in disease progression of non-cancerous diseases such as neurodegeneration, liver disease, kidney disease, intestinal irritability syndrome and airway hypersensitivity. Thus, abnormal expression of ERp57 could be used as promising biomarker for cancer diagnosis and prognosis based on the previous studies. In this regard, current study was aimed to review the literature, which have been elucidate the role of ERp57 protein expression in both non-cancer and cancer disease. Overall, most studies have shown that inhibiting/knocking out of ERp57 could inhibit the cell proliferation and also induce apoptosis in both human cancerous and non-cancerous cells. Also, it has been suggested that the overexpression of ERp57 could intensify the cancer development. Therefore, it could be hypothesized that targeting of ERp57 might be a potential treatment in cancerous and non-cancerous diseases.
{"title":"A Review of the Role of ERp57 in Cancerous and Non-Cancerous Cell Physiology and its Potential as a Therapeutic Target","authors":"F. Rahbar, Avid Farhang Fagheh, A. Khosravi, Siavash Shariatzadeh, R. Akhavan-Sigari","doi":"10.32604/mcb.2021.017750","DOIUrl":"https://doi.org/10.32604/mcb.2021.017750","url":null,"abstract":"The protein ERp57 is a stress-responsive protein, mainly exists in the endoplasmic reticulum (ER), and a small amount in the cell membrane, cytoplasm, nucleus and mitochondria, which is involved in the signal transduction from the cell surface, the regulation process that occurs in the nucleus, and the formation of polymer protein complexes involved in DNA repair. Various degrees of ERp57 dysregulation has been observed in many types of non-communicable diseases especially in cancers. Previous studies showed that the expression of ERp57 could play a key role in occurrence and development of cancers such as breast cancer, gastric cancer, ovarian cancer, etc.; in addition, it has been suggested to play a pivotal role in disease progression of non-cancerous diseases such as neurodegeneration, liver disease, kidney disease, intestinal irritability syndrome and airway hypersensitivity. Thus, abnormal expression of ERp57 could be used as promising biomarker for cancer diagnosis and prognosis based on the previous studies. In this regard, current study was aimed to review the literature, which have been elucidate the role of ERp57 protein expression in both non-cancer and cancer disease. Overall, most studies have shown that inhibiting/knocking out of ERp57 could inhibit the cell proliferation and also induce apoptosis in both human cancerous and non-cancerous cells. Also, it has been suggested that the overexpression of ERp57 could intensify the cancer development. Therefore, it could be hypothesized that targeting of ERp57 might be a potential treatment in cancerous and non-cancerous diseases.","PeriodicalId":48719,"journal":{"name":"Molecular & Cellular Biomechanics","volume":"33 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86618202","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}
Pub Date : 2021-01-01DOI: 10.32604/MCB.2021.014287
Guangyu Zhai, Kuan Zhang, G. Chai
The study mainly analyzed the relationship between temperature and the upper respiratory tract infections (URI) in Lanzhou. We collected the daily URI and meteorological data from 2010 to 2015. A distributed lag non-linear model was used to examine the relationship and potential effects of different temperatures and different lag days on the morbidity of URI. The results showed that the morbidity of URI was significantly related to the meteorological factors, and the peak of the onset of the disease usually occurred between November and February the next year. The correlation analysis was carried out between meteorological factors and URI cases, and the result revealed that the daily morbidity of URI in Lanzhou was related to air temperature, air pressure, and wind speed. The exposure effect curve of average daily temperature to different sex and different age groups in Lanzhou displayed an M-shaped. Temperature had a certain lag effect on the daily morbidity of URI. For low temperature, it appeared on the present day, and the maximum impact appeared at lag 2 days and persisted for 12 days. The female was more vulnerable than the male, and the impact was obvious in teenagers and the elderly and not obvious in adult. Meteorological factors play an important role in the occurrence of URI in Lanzhou, but the main factor is low temperature. Temperature can trigger the morbidity of URI directly; it can induce various symptoms of URI (such as cold, sore throat and rhinitis) and directly affect the distribution of URI in the population.
{"title":"Impact of Temperature on Upper Respiratory Tract Infections in Lanzhou Based on the Distributed Lag Model","authors":"Guangyu Zhai, Kuan Zhang, G. Chai","doi":"10.32604/MCB.2021.014287","DOIUrl":"https://doi.org/10.32604/MCB.2021.014287","url":null,"abstract":"The study mainly analyzed the relationship between temperature and the upper respiratory tract infections (URI) in Lanzhou. We collected the daily URI and meteorological data from 2010 to 2015. A distributed lag non-linear model was used to examine the relationship and potential effects of different temperatures and different lag days on the morbidity of URI. The results showed that the morbidity of URI was significantly related to the meteorological factors, and the peak of the onset of the disease usually occurred between November and February the next year. The correlation analysis was carried out between meteorological factors and URI cases, and the result revealed that the daily morbidity of URI in Lanzhou was related to air temperature, air pressure, and wind speed. The exposure effect curve of average daily temperature to different sex and different age groups in Lanzhou displayed an M-shaped. Temperature had a certain lag effect on the daily morbidity of URI. For low temperature, it appeared on the present day, and the maximum impact appeared at lag 2 days and persisted for 12 days. The female was more vulnerable than the male, and the impact was obvious in teenagers and the elderly and not obvious in adult. Meteorological factors play an important role in the occurrence of URI in Lanzhou, but the main factor is low temperature. Temperature can trigger the morbidity of URI directly; it can induce various symptoms of URI (such as cold, sore throat and rhinitis) and directly affect the distribution of URI in the population.","PeriodicalId":48719,"journal":{"name":"Molecular & Cellular Biomechanics","volume":"9 4 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78467572","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}
Pub Date : 2021-01-01DOI: 10.32604/mcb.2021.017503
Yang Li, Runxin Fang, Ren-cheng Wang, Qiming Dai, Zhiyong Li, G. Ma
Longitudinal stent foreshortening is a known phenomenon, however, the impact of coronary artery curvature on longitudinal stent foreshortening remains unclear. The aim of this study is to determine the impact of coronary artery curvature on the longitudinal stent foreshortening in the real-world scenarios. A total of 86 consecutive patients underwent coronary stent implantation were included in the present study. The degree of coronary artery curvature was defined as the length of the coronary artery curvature divided by the straight length. Longitudinal stent foreshortening was defined as the stent length after implantation divided by the stent length before implantation. The mean longitudinal foreshortening rate of coronary stents was about 94% in curved coronary arteries. Longitudinal stent foreshortening rate was positively correlated with the degree of coronary artery curvature (r = –0.86, P < 0.01). Coronary artery curvature is associated with significant longitudinal foreshortening of coronary stents, thus longitudinal foreshortening should be considered on deciding the stent length in curved coronary artery and a longer stent is usually needed in curved coronary artery.
纵向支架缩短是一种已知的现象，然而，冠状动脉弯曲对纵向支架缩短的影响尚不清楚。本研究的目的是确定在现实情况下冠状动脉曲率对纵向支架缩短的影响。本研究共纳入86例连续行冠状动脉支架植入术的患者。冠状动脉弯曲度定义为冠状动脉弯曲长度除以直长。纵向支架预缩定义为植入后的支架长度除以植入前的支架长度。在弯曲的冠状动脉中，冠脉支架的平均纵向缩短率约为94%。纵向支架缩短率与冠状动脉弯曲度呈正相关(r = -0.86, P < 0.01)。冠状动脉弯曲与冠状动脉支架明显的纵向预缩有关，因此在确定弯曲冠状动脉支架长度时应考虑纵向预缩，弯曲冠状动脉通常需要更长的支架。
{"title":"Impact of Coronary Artery Curvature on the Longitudinal Stent Foreshortening: Real-World Observations","authors":"Yang Li, Runxin Fang, Ren-cheng Wang, Qiming Dai, Zhiyong Li, G. Ma","doi":"10.32604/mcb.2021.017503","DOIUrl":"https://doi.org/10.32604/mcb.2021.017503","url":null,"abstract":"Longitudinal stent foreshortening is a known phenomenon, however, the impact of coronary artery curvature on longitudinal stent foreshortening remains unclear. The aim of this study is to determine the impact of coronary artery curvature on the longitudinal stent foreshortening in the real-world scenarios. A total of 86 consecutive patients underwent coronary stent implantation were included in the present study. The degree of coronary artery curvature was defined as the length of the coronary artery curvature divided by the straight length. Longitudinal stent foreshortening was defined as the stent length after implantation divided by the stent length before implantation. The mean longitudinal foreshortening rate of coronary stents was about 94% in curved coronary arteries. Longitudinal stent foreshortening rate was positively correlated with the degree of coronary artery curvature (r = –0.86, P < 0.01). Coronary artery curvature is associated with significant longitudinal foreshortening of coronary stents, thus longitudinal foreshortening should be considered on deciding the stent length in curved coronary artery and a longer stent is usually needed in curved coronary artery.","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":"81646298","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}
Pub Date : 2021-01-01DOI: 10.32604/mcb.2021.015605
B Umadevi, C. V. Vinay, P. A. Dinesh
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.
{"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}
Pub Date : 2021-01-01DOI: 10.32604/MCB.2021.014748
Boqing Li, X. Bai, Yongli Zhu
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.
{"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}
Pub Date : 2021-01-01DOI: 10.32604/MCB.2021.014394
Yiran Tian
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.
{"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}
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.
{"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}
Pub Date : 2021-01-01DOI: 10.32604/mcb.2021.016238
Zhonghang Zhao, A. Ji, Changsheng Chen
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.
{"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}
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