The Impact of Biomechanics in Tissue Engineering and Regenerative Medicine

Science.gov (United States)

Butler, David L.; Goldstein, Steven A.; Guo, X. Edward; Kamm, Roger; Laurencin, Cato T.; McIntire, Larry V.; Mow, Van C.; Nerem, Robert M.; Sah, Robert L.; Soslowsky, Louis J.; Spilker, Robert L.; Tranquillo, Robert T.

2009-01-01

Biomechanical factors profoundly influence the processes of tissue growth, development, maintenance, degeneration, and repair. Regenerative strategies to restore damaged or diseased tissues in vivo and create living tissue replacements in vitro have recently begun to harness advances in understanding of how cells and tissues sense and adapt to their mechanical environment. It is clear that biomechanical considerations will be fundamental to the successful development of clinical therapies based on principles of tissue engineering and regenerative medicine for a broad range of musculoskeletal, cardiovascular, craniofacial, skin, urinary, and neural tissues. Biomechanical stimuli may in fact hold the key to producing regenerated tissues with high strength and endurance. However, many challenges remain, particularly for tissues that function within complex and demanding mechanical environments in vivo. This paper reviews the present role and potential impact of experimental and computational biomechanics in engineering functional tissues using several illustrative examples of past successes and future grand challenges. PMID:19583462

Bladder biomechanics and the use of scaffolds for regenerative medicine in the urinary bladder

DEFF Research Database (Denmark)

Ajalloueian, Fatemeh; Lemon, Greg; Hilborn, Jöns

2018-01-01

and scaffolds. To replicate an organ that is under frequent mechanical loading and unloading, special attention towards fulfilling its biomechanical requirements is necessary. Several biological and synthetic scaffolds are available, with various characteristics that qualify them for use in bladder regeneration...... in vitro and in vivo, including in the treatment of clinical conditions. The biomechanical properties of the native bladder can be investigated using a range of mechanical tests for standardized assessments, as well as mathematical and computational bladder biomechanics. Despite a large body of research...

In vitro biomechanical and biocompatible evaluation of natural hydroxyapatite/chitosan composite for bone repair.

Science.gov (United States)

Lü, Xiaoying; Zheng, Buzhong; Tang, Xiaojun; Zhao, Lifeng; Lu, Jieyan; Zhang, Zhiwei; Zhang, Jizhong; Cui, Wei

2011-01-01

To evaluate the biomechanical properties and biocompatibility of natural hydroxyapatite/chitosan (HA/CS) composites. The natural HA/CS composites with a different proportion of HA and CS were prepared by the cross-linking method, and then the compressive strength, microstructure and pH values of extracts from these composites were measured by SEM and pH meter, respectively. Subsequently, the biocompatibility of the composites was evaluated by means of a series of biological tests, including MTT, acute systemic toxicity, heat source, and hemolysis tests in vitro. The chitosan content in the composites had significantly influenced the mechanical properties and microstructure of the composites. The pH value of the composite extract was approximately 7.0, which was very close to that of human plasma. Furthermore, the natural HA/CS composites showed no cytotoxicity, irritation, teratogenicity, carcinogenicity and special pyrogen. These results indicated that the natural HA/CS composite may be a potential bone repair material.

Evaluation of a minimally invasive procedure for sacroiliac joint fusion – an in vitro biomechanical analysis of initial and cycled properties

Directory of Open Access Journals (Sweden)

Lindsey DP

2014-05-01

Full Text Available Derek P Lindsey,1 Luis Perez-Orribo,2 Nestor Rodriguez-Martinez,2 Phillip M Reyes,2 Anna Newcomb,2 Alexandria Cable,2 Grace Hickam,2 Scott A Yerby,1 Neil R Crawford21SI-BONE, Inc., San Jose, CA, USA; 2Spinal Biomechanics Research Laboratory, Barrow Neurological Institute, St Joseph's Hospital and Medical Center, Phoenix, AZ, USAIntroduction: Sacroiliac (SI joint pain has become a recognized factor in low back pain. The purpose of this study was to investigate the effect of a minimally invasive surgical SI joint fusion procedure on the in vitro biomechanics of the SI joint before and after cyclic loading.Methods: Seven cadaveric specimens were tested under the following conditions: intact, posterior ligaments (PL and pubic symphysis (PS cut, treated (three implants placed, and after 5,000 cycles of flexion–extension. The range of motion (ROM in flexion–extension, lateral bending, and axial rotation was determined with an applied 7.5 N • m moment using an optoelectronic system. Results for each ROM were compared using a repeated measures analysis of variance (ANOVA with a Holm–Šidák post-hoc test.Results: Placement of three fusion devices decreased the flexion–extension ROM. Lateral bending and axial rotation were not significantly altered. All PL/PS cut and post-cyclic ROMs were larger than in the intact condition. The 5,000 cycles of flexion–extension did not lead to a significant increase in any ROMs.Discussion: In the current model, placement of three 7.0 mm iFuse Implants significantly decreased the flexion–extension ROM. Joint ROM was not increased by 5,000 flexion–extension cycles.Keywords: biomechanics, iliosacral, arthrodesis, cadaver

Combined Effects of Scaffold Stiffening and Mechanical Preconditioning Cycles on Construct Biomechanics, Gene Expression, and Tendon Repair Biomechanics

OpenAIRE

Nirmalanandhan, Victor Sanjit; Juncosa-Melvin, Natalia; Shearn, Jason T.; Boivin, Gregory P.; Galloway, Marc T.; Gooch, Cynthia; Bradica, Gino; Butler, David L.

2009-01-01

Our group has previously reported that in vitro mechanical stimulation of tissue-engineered tendon constructs significantly increases both construct stiffness and the biomechanical properties of the repair tissue after surgery. When optimized using response surface methodology, our results indicate that a mechanical stimulus with three components (2.4% strain, 3000 cycles/day, and one cycle repetition) produced the highest in vitro linear stiffness. Such positive correlations between construc...

[Foot stress simulator for biomechanical in vitro studies of lower leg segments].

Science.gov (United States)

Rosenbaum, D; Schmitt, H; Bertsch, C; Bauer, G; Claes, L

1996-05-01

In this paper we describe a foot-loading simulator that permits in vitro studies on human lower leg and foot specimens. The specimens are fixed in a jig and loaded axially with the aid of a pneumatic cylinder. The resulting transfer of forces through the ankle joint complex and Chopart's articulation (line) can be demonstrated on a pressure-sensitive film. Plantar pressure measurements obtained in patients or normal subjects can be used to ensure the comparability of in vivo and in vitro measurements. The supporting platform can be tilted in such a manner as to provide a range of foot positions up to 20 degrees in plantar- or dorsiflexion, eversion or inversion. The system is used for investigating the effects on the intra-articular pressures and plantar pressure patterns of physiological muscle activity and pathological conditions following fracture of the calcaneum or damage to the lateral ligament. By way of an example, the effects of muscle forces on plantar pressure distribution are presented.

Direct lateral approach to lumbar fusion is a biomechanically equivalent alternative to the anterior approach: an in vitro study.

Science.gov (United States)

Laws, Cory J; Coughlin, Dezba G; Lotz, Jeffrey C; Serhan, Hassan A; Hu, Serena S

2012-05-01

A human cadaveric biomechanical study of lumbar mobility before and after fusion and with or without supplemental instrumentation for 5 instrumentation configurations. To determine the biomechanical differences between anterior lumbar interbody fusion (ALIF) and direct lateral interbody fusion (DLIF) with and without supplementary instrumentation. Some prior studies have compared various surgical approaches using the same interbody device whereas others have investigated the stabilizing effect of supplemental instrumentation. No published studies have performed a side-by-side comparison of standard and minimally invasive techniques with and without supplemental instrumentation. Eight human lumbosacral specimens (16 motion segments) were tested in each of the 5 following configurations: (1) intact, (2) with ALIF or DLIF cage, (3) with cage plus stabilizing plate, (4) with cage plus unilateral pedicle screw fixation (PSF), and (5) with cage plus bilateral PSF. Pure moments were applied to induce specimen flexion, extension, lateral bending, and axial rotation. Three-dimensional kinematic responses were measured and used to calculate range of motion, stiffness, and neutral zone. Compared to the intact state, DLIF significantly reduced range of motion in flexion, extension, and lateral bending (P = 0.0117, P = 0.0015, P = 0.0031). Supplemental instrumentation significantly increased fused-specimen stiffness for both DLIF and ALIF groups. For the ALIF group, bilateral PSF increased stiffness relative to stand-alone cage by 455% in flexion and 317% in lateral bending (P = 0.0009 and P < 0.0001). The plate increased ALIF group stiffness by 211% in extension and 256% in axial rotation (P = 0.0467 and P = 0.0303). For the DLIF group, bilateral PSF increased stiffness by 350% in flexion and 222% in extension (P < 0.0001 and P = 0.0008). No differences were observed between ALIF and DLIF groups supplemented with bilateral PSF. Our data support that the direct lateral approach

Biomechanical study of percutaneous lumbar diskectomy

International Nuclear Information System (INIS)

Li Yuan; Huang Xianglong; Shen Tianzhen; Hu Zhou; Hong Shuizong; Mei Haiying

2003-01-01

Objective: To investigate the stiffness of lumbar spine after the injury caused by percutaneous diskectomy and evaluate the efficiency of percutaneous lumbar diskectomy by biomechanical study. Methods: Four fresh lumbar specimens were used to analyse load-displacement curves in the intact lumbar spine and vertical disc-injured lumbar spine. The concepts of average flexibility coefficient (f) and standardized average flexibility coefficient (fs) were also introduced. Results: The load-displacement curves showed a good stabilization effect of the intact lumbar spine and disc-injured lumbar spine in flexion, extension, right and left bending. The decrease of anti-rotation also can be detected (P<0.05). Conclusion: In biomechanical study, percutaneous lumbar diskectomy is one of the efficiency methods to treat lumbar diac hernia

A Simplified Method of Opacifying and Mixing Acrylic Cement for Percutaneous Vertebroplasty: A Clinical and In Vitro Study

International Nuclear Information System (INIS)

Teng Gaojun; He Shicheng; Deng Gang; Guo Jinhe; Fang Wen; Zhu Guangyu

2005-01-01

The objective of this study was to simplify the opacifying mixing process of the bone cement and contrast used for percutaneous vertebroplasty (PVP). We performed a biomechanical study of polymethyl methacrylate (PMMA) (Corinplast TM 3) using three different mixtures of PMMA, monomer, and contrast: group I, 2:1; group II, 3:2; group III, 3:2:1 ratio of powder/monomer/iodinated contrast (Omnipaque). In vitro biomechanical testing of ultimate compressive strength was carried out in all samples. Following the conclusion of a proper bone cement mixture regimen drawn from the in vitro study, PVP was performed in 125 patients: 58 with cancer, 12 with hemangioma, and 54 with osteoporotic fracture. The ultimate compressive strength in group III was decreased by 38% compared to groups II and I. Proper fluoroscopic visualization was achieved in all PVP procedures using this mixture. There were no major complications associated with injection of the cement mixture. Complete (CR) and partial response (PR) was obtained in 64% and 32.8%, respectively. No further vertebral collapse occurred during follow-up. The regimen using iodinated contrast for cement visualization during PVP provides a simple and convenient new method for mixing. Although the biomechanical strength is altered by the contrast medium added, it seems insignificant in clinical practice based on the authors' limited experience

Confidence crisis of results in biomechanics research.

Science.gov (United States)

Knudson, Duane

2017-11-01

Many biomechanics studies have small sample sizes and incorrect statistical analyses, so reporting of inaccurate inferences and inflated magnitude of effects are common in the field. This review examines these issues in biomechanics research and summarises potential solutions from research in other fields to increase the confidence in the experimental effects reported in biomechanics. Authors, reviewers and editors of biomechanics research reports are encouraged to improve sample sizes and the resulting statistical power, improve reporting transparency, improve the rigour of statistical analyses used, and increase the acceptance of replication studies to improve the validity of inferences from data in biomechanics research. The application of sports biomechanics research results would also improve if a larger percentage of unbiased effects and their uncertainty were reported in the literature.

Toward characterization of craniofacial biomechanics.

Science.gov (United States)

Szwedowski, Tomasz D; Whyne, Cari M; Fialkov, Jeffrey A

2010-01-01

Surgical reconstruction of craniofacial deformities has advanced significantly in recent years. However, unlike orthopedic surgery of the appendicular skeleton, the biomechanical characterization of the human craniofacial skeleton (CFS) has yet to be elucidated. Attempts to simplify facial skeletal structure into straightforward mechanical device analogies have been insufficient in delineating craniofacial biomechanics. Advanced computational engineering analysis methods offer the potential to accurately and completely define the internal mechanical environment of the CFS. This study developed a finite element (FE) model in the I-deas 10 FEM software package of a preserved cadaveric human CFS and compared the predictions of this model against in vitro strain measurement of simulated occlusal loading forces from a single masseter muscle. The FE model applied shell element modeling to capture the behavior of the thin cortical bone that may play an important role in stabilizing the facial structures against functional loads. In vitro testing included strain measurements at 12 locations for a total of 16 independent channels with less than 150 N of tensile force applied through the masseter muscle into the zygomatic arch origin at 4 different orientations, with 3 trials of 500 recorded data points for each loading orientation. Linear regression analysis yielded a moderate prediction (r = 0.57) between the model and experimentally measured strains. Exclusion of strain comparisons in regions that required greater modeling assumptions greatly improved the correlation (r = 0.70). Future validation studies will benefit from improved placement of strain gauges as guided by FE model predicted strain patterns.

Research Techniques in Biomechanics.

Science.gov (United States)

Ward, Terry

Biomechanics involves the biological human beings interacting with his/her mechanical environment. Biomechanics research is being done in connection with sport, physical education, and general motor behavior, and concerns mechanics independent of implements. Biomechanics research falls in the following two general categories: (1) that specific…

Combined effects of scaffold stiffening and mechanical preconditioning cycles on construct biomechanics, gene expression, and tendon repair biomechanics.

Science.gov (United States)

Nirmalanandhan, Victor Sanjit; Juncosa-Melvin, Natalia; Shearn, Jason T; Boivin, Gregory P; Galloway, Marc T; Gooch, Cynthia; Bradica, Gino; Butler, David L

2009-08-01

Our group has previously reported that in vitro mechanical stimulation of tissue-engineered tendon constructs significantly increases both construct stiffness and the biomechanical properties of the repair tissue after surgery. When optimized using response surface methodology, our results indicate that a mechanical stimulus with three components (2.4% strain, 3000 cycles/day, and one cycle repetition) produced the highest in vitro linear stiffness. Such positive correlations between construct and repair stiffness after surgery suggest that enhancing structural stiffness before surgery could not only accelerate repair stiffness but also prevent premature failures in culture due to poor mechanical integrity. In this study, we examined the combined effects of scaffold crosslinking and subsequent mechanical stimulation on construct mechanics and biology. Autologous tissue-engineered constructs were created by seeding mesenchymal stem cells (MSCs) from 15 New Zealand white rabbits on type I collagen sponges that had undergone additional dehydrothermal crosslinking (termed ADHT in this manuscript). Both constructs from each rabbit were mechanically stimulated for 8h/day for 12 consecutive days with half receiving 100 cycles/day and the other half receiving 3000 cycles/day. These paired MSC-collagen autologous constructs were then implanted in bilateral full-thickness, full-length defects in the central third of rabbit patellar tendons. Increasing the number of in vitro cycles/day delivered to the ADHT constructs in culture produced no differences in stiffness or gene expression and no changes in biomechanical properties or histology 12 weeks after surgery. Compared to MSC-based repairs from a previous study that received no additional treatment in culture, ADHT crosslinking of the scaffolds actually lowered the 12-week repair stiffness. Thus, while ADHT crosslinking may initially stiffen a construct in culture, this specific treatment also appears to mask any benefits

The biomechanical effect of transverse connectors use in a pre- and postlaminectomy model of the posterior cervical spine: an in vitro cadaveric study.

Science.gov (United States)

Majid, Kamran; Gudipally, Manasa; Hussain, Mir; Moldavsky, Mark; Khalil, Saif

2011-12-15

An in vitro biomechanical study investigating the effect of transverse connectors on posterior cervical stabilization system in a laminectomy model. To evaluate the optimal design, number, and location of the transverse connectors in stabilizing long segment posterior instrumentation in the cervical spine. In the cervical spine, lateral mass screw (LMS) fixation is used for providing stability after decompression. Transverse connectors have been used to augment segmental posterior instrumentation. However, in the cervical region the optimal design, number, and the location of transverse connectors is not known. Seven fresh human cervicothoracic cadaveric spines (C2-T1) were tested by applying ±1.5 Nm moments in flexion (F), extension (E), lateral bending (LB), and axial rotation (AR). After testing the intact condition, LMS/rods were placed and then were tested with two different transverse connectors (top-loading connector [TL] and the head-to-head [HH] connector) in multiple levels, pre- and postlaminectomy (PL). LMS significantly reduced segmental motion by 77.2% in F, 75.6% in E, 86.6% in LB, and 86.1% in AR prelaminectomy and by 75.4% in F, 76% in E, 80.6% in LB, and 76.4% in AR postlaminectomy compared to intact (P transverse connectors is significant in AR, when using two connectors at the proximal and distal ends, compared to one connector. In a clinical setting, this data may guide surgeons on transverse connector configurations to consider during posterior cervical instrumentation.

Biomechanics in Schools.

Science.gov (United States)

Vincent, J. F. V.

1980-01-01

Examines current usage of the term "biomechanics" and emphasizes the importance of differentiating between structure and material. Describes current prolects in biomechanics and lists four points about the educational significance of the field. (GS)

Integrated Circuit-Based Biofabrication with Common Biomaterials for Probing Cellular Biomechanics.

Science.gov (United States)

Sung, Chun-Yen; Yang, Chung-Yao; Yeh, J Andrew; Cheng, Chao-Min

2016-02-01

Recent advances in bioengineering have enabled the development of biomedical tools with modifiable surface features (small-scale architecture) to mimic extracellular matrices and aid in the development of well-controlled platforms that allow for the application of mechanical stimulation for studying cellular biomechanics. An overview of recent developments in common biomaterials that can be manufactured using integrated circuit-based biofabrication is presented. Integrated circuit-based biofabrication possesses advantages including mass and diverse production capacities for fabricating in vitro biomedical devices. This review highlights the use of common biomaterials that have been most frequently used to study cellular biomechanics. In addition, the influence of various small-scale characteristics on common biomaterial surfaces for a range of different cell types is discussed. Copyright © 2015 Elsevier Ltd. All rights reserved.

Biomechanical evaluation of one-piece and two-piece small-diameter dental implants: In-vitro experimental and three-dimensional finite element analyses.

Science.gov (United States)

Wu, Aaron Yu-Jen; Hsu, Jui-Ting; Chee, Winston; Lin, Yun-Te; Fuh, Lih-Jyh; Huang, Heng-Li

2016-09-01

Small-diameter dental implants are associated with a higher risk of implant failure. This study used both three-dimensional finite-element (FE) simulations and in-vitro experimental tests to analyze the stresses and strains in both the implant and the surrounding bone when using one-piece (NobelDirect) and two-piece (NobelReplace) small-diameter implants, with the aim of understanding the underlying biomechanical mechanisms. Six experimental artificial jawbone models and two FE models were prepared for one-piece and two-piece 3.5-mm diameter implants. Rosette strain gauges were used for in-vitro tests, with peak values of the principal bone strain recorded with a data acquisition system. Implant stability as quantified by Periotest values (PTV) were also recorded for both types of implants. Experimental data were analyzed statistically using Wilcoxon's rank-sum test. In FE simulations, the peak value and distribution of von-Mises stresses in the implant and bone were selected for evaluation. In in-vitro tests, the peak bone strain was 42% lower for two-piece implants than for one-piece implants. The PTV was slightly lower for one-piece implants (PTV = -6) than for two-piece implants (PTV = -5). In FE simulations, the stresses in the bone and implant were about 23% higher and 12% lower, respectively, for one-piece implants than those for two-piece implants. Due to the higher peri-implant bone stresses and strains, one-piece implants (NobelDirect) might be not suitable for use as small-diameter implants. Copyright © 2016. Published by Elsevier B.V.

Using Clinical Gait Case Studies to Enhance Learning in Biomechanics

Science.gov (United States)

Chester, Victoria

2011-01-01

Clinical case studies facilitate the development of clinical reasoning strategies through knowledge and integration of the basic sciences. Case studies have been shown to be more effective in developing problem-solving abilities than the traditional lecture format. To enhance the learning experiences of students in biomechanics, clinical case…

Recent microfluidic devices for studying gamete and embryo biomechanics.

Science.gov (United States)

Lai, David; Takayama, Shuichi; Smith, Gary D

2015-06-25

The technical challenges of biomechanic research such as single cell analysis at a high monetary cost, labor, and time for just a small number of measurements is a good match to the strengths of microfluidic devices. New scientific discoveries in the fertilization and embryo development process, of which biomechanics is a major subset of interest, is crucial to fuel the continual improvement of clinical practice in assisted reproduction. The following review will highlight some recent microfluidic devices tailored for gamete and embryo biomechanics where biomimicry arises as a major theme of microfluidic device design and function, and the application of fundamental biomechanic principles are used to improve outcomes of cryopreservation. Copyright © 2015 Elsevier Ltd. All rights reserved.

In vitro toxicological nanoparticle studies under flow exposure

International Nuclear Information System (INIS)

Sambale, Franziska; Stahl, Frank; Bahnemann, Detlef; Scheper, Thomas

2015-01-01

The use of nanoparticles is becoming increasingly common in industry and everyday objects. Thus, extensive risk management concerning the potential health risk of nanoparticles is important. Currently, in vitro nanoparticle testing is mainly performed under static culture conditions without any shear stress. However, shear stress is an important biomechanical parameter. Therefore, in this study, a defined physiological flow to different mammalian cell lines such as A549 cells and NIH-3T3 cells has been applied. The effects of zinc oxide and titanium dioxide nanoparticles (TiO 2 -NP), respectively, were investigated under both static and dynamic conditions. Cell viability, cell morphology, and adhesion were proven and compared to the static cell culture. Flow exposure had an impact on the cellular morphology of the cells. NIH-3T3 cells were elongated in the direction of flow and A549 cells exhibited vesicles inside the cells. Zinc oxide nanoparticles reduced the cell viability in the static and in the dynamic culture; however, the dynamic cultures were more sensitive. In the static culture and in the dynamic culture, TiO 2 -NP did not affect cell viability. In conclusion, dynamic culture conditions are important for further in vitro investigations and provide more relevant results than static culture conditions

In vitro toxicological nanoparticle studies under flow exposure

Energy Technology Data Exchange (ETDEWEB)

Sambale, Franziska, E-mail: sambale@iftc.uni-hannover.de; Stahl, Frank; Bahnemann, Detlef; Scheper, Thomas [Gottfried Wilhelm Leibniz University Hanover, Institute for Technical Chemistry (Germany)

2015-07-15

The use of nanoparticles is becoming increasingly common in industry and everyday objects. Thus, extensive risk management concerning the potential health risk of nanoparticles is important. Currently, in vitro nanoparticle testing is mainly performed under static culture conditions without any shear stress. However, shear stress is an important biomechanical parameter. Therefore, in this study, a defined physiological flow to different mammalian cell lines such as A549 cells and NIH-3T3 cells has been applied. The effects of zinc oxide and titanium dioxide nanoparticles (TiO{sub 2}-NP), respectively, were investigated under both static and dynamic conditions. Cell viability, cell morphology, and adhesion were proven and compared to the static cell culture. Flow exposure had an impact on the cellular morphology of the cells. NIH-3T3 cells were elongated in the direction of flow and A549 cells exhibited vesicles inside the cells. Zinc oxide nanoparticles reduced the cell viability in the static and in the dynamic culture; however, the dynamic cultures were more sensitive. In the static culture and in the dynamic culture, TiO{sub 2}-NP did not affect cell viability. In conclusion, dynamic culture conditions are important for further in vitro investigations and provide more relevant results than static culture conditions.

The Role of Minimally Invasive Vertebral Body Stent on Reduction of the Deflation Effect After Kyphoplasty: A Biomechanical Study.

Science.gov (United States)

Wang, Dalin; Zheng, Shengnai; Liu, An; Xu, Jie; Du, Xiaotao; Wang, Yijin; Wang, Liming

2018-03-15

Biomechanical investigation using cadaver spines. The aim of the present study was to assess the magnitude of the deflation effect after balloon kyphoplasty (BKP) or use of minimally invasive vertebral body stent (MIVBS) in in vitro biomechanical condition. BKP is a well-established minimally invasive treatment option for osteoporotic vertebral compression fractures. However, this technique can lead to a secondary height loss-known as the "deflation effect"-causing intrasegmental kyphosis and an overall alignment failure. The study was conducted on 24 human cadaveric vertebral bodies (T12-L5). After creating a compression fracture model, the fractured vertebral bodies were reduced by BKP (n = 12) or by MIVBS (n = 12) and then augmented with polymethyl methacrylate bone cement. Each step of the procedure was performed under fluoroscopic guidance and the results were analyzed quantitatively. Finally, the strength and stiffness of augmented vertebral bodies were measured by biomechanical tests. Complete initial reduction of the fractured vertebral body height was achieved by both systems. Secondary loss of reduction after balloon deflation was significantly greater in the BKP group (2.36 ± 0.63 mm vs. 0.34 ± 0.43 mm in the MIVBS group; P deflation effect after BKP can be significantly decreased with the use of the MIVBS technique. N/A.

A review of biomechanics of the shoulder and biomechanical concepts of rotator cuff repair

Directory of Open Access Journals (Sweden)

Nobuyuki Yamamoto

2015-01-01

Full Text Available In this article, we describe the basic knowledge about shoulder biomechanics, which is thought to be useful for surgeons. Some clinical reports have described that the excellent outcome after cuff repair without acromioplasty and a limited acromioplasty might be enough for subacromial decompression. It was biomechanically demonstrated that a 10-mm medial shift of the tendon repair site has a minimum effect on biomechanics. Many biomechanical studies reported that the transosseous equivalent repair was superior to other techniques, although the tendon may lose its inherent elasticity. We herein introduce our recent experiment data and latest information on biomechanics.

FUNDAMENTALS OF BIOMECHANICS

Directory of Open Access Journals (Sweden)

Duane Knudson

2007-09-01

Full Text Available DESCRIPTION This book provides a broad and in-depth theoretical and practical description of the fundamental concepts in understanding biomechanics in the qualitative analysis of human movement. PURPOSE The aim is to bring together up-to-date biomechanical knowledge with expert application knowledge. Extensive referencing for students is also provided. FEATURES This textbook is divided into 12 chapters within four parts, including a lab activities section at the end. The division is as follows: Part 1 Introduction: 1.Introduction to biomechanics of human movement; 2.Fundamentals of biomechanics and qualitative analysis; Part 2 Biological/Structural Bases: 3.Anatomical description and its limitations; 4.Mechanics of the musculoskeletal system; Part 3 Mechanical Bases: 5.Linear and angular kinematics; 6.Linear kinetics; 7.Angular kinetics; 8.Fluid mechanics; Part 4 Application of Biomechanics in Qualitative Analysis :9.Applying biomechanics in physical education; 10.Applying biomechanics in coaching; 11.Applying biomechanics in strength and conditioning; 12.Applying biomechanics in sports medicine and rehabilitation. AUDIENCE This is an important reading for both student and educators in the medicine, sport and exercise-related fields. For the researcher and lecturer it would be a helpful guide to plan and prepare more detailed experimental designs or lecture and/or laboratory classes in exercise and sport biomechanics. ASSESSMENT The text provides a constructive fundamental resource for biomechanics, exercise and sport-related students, teachers and researchers as well as anyone interested in understanding motion. It is also very useful since being clearly written and presenting several ways of examples of the application of biomechanics to help teach and apply biomechanical variables and concepts, including sport-related ones

Teaching undergraduate biomechanics with Just-in-Time Teaching.

Science.gov (United States)

Riskowski, Jody L

2015-06-01

Biomechanics education is a vital component of kinesiology, sports medicine, and physical education, as well as for many biomedical engineering and bioengineering undergraduate programmes. Little research exists regarding effective teaching strategies for biomechanics. However, prior work suggests that student learning in undergraduate physics courses has been aided by using the Just-in-Time Teaching (JiTT). As physics understanding plays a role in biomechanics understanding, the purpose of study was to evaluate the use of a JiTT framework in an undergraduate biomechanics course. This two-year action-based research study evaluated three JiTT frameworks: (1) no JiTT; (2) mathematics-based JiTT; and (3) concept-based JiTT. A pre- and post-course assessment of student learning used the biomechanics concept inventory and a biomechanics concept map. A general linear model assessed differences between the course assessments by JiTT framework in order to evaluate learning and teaching effectiveness. The results indicated significantly higher learning gains and better conceptual understanding in a concept-based JiTT course, relative to a mathematics-based JiTT or no JiTT course structure. These results suggest that a course structure involving concept-based questions using a JiTT strategy may be an effective method for engaging undergraduate students and promoting learning in biomechanics courses.

Biomechanics in dermatology: Recent advances and future directions.

Science.gov (United States)

Lewinson, Ryan T; Haber, Richard M

2017-02-01

Biomechanics is increasingly being recognized as an important research area in dermatology. To highlight only a few examples, biomechanics has contributed to the development of novel topical therapies for aesthetic and medical purposes, enhanced our understanding of the pathogenesis of plantar melanoma, and provided insight into the epidemiology of psoriatic disease. This article summarizes the findings from recent studies to demonstrate the important role that biomechanics may have in dermatologic disease and therapy and places these biomechanical findings in a clinical context for the practicing physician. In addition, areas for future biomechanics research and development in dermatology are discussed. Copyright © 2016 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.

Important learning factors in high- and low-achieving students in undergraduate biomechanics.

Science.gov (United States)

Hsieh, ChengTu; Knudson, Duane

2017-07-21

The purpose of the present study was to document crucial factors associated with students' learning of biomechanical concepts, particularly between high- and-low achieving students. Students (N = 113) from three introductory biomechanics classes at two public universities volunteered for the study. Two measures of students' learning were obtained, final course grade and improvement on the Biomechanics Concept Inventory version 3 administered before and after the course. Participants also completed a 15-item questionnaire documenting student learning characteristics, effort, and confidence. Partial correlations controlling for all other variables in the study, confirmed previous studies that students' grade point average (p biomechanics, (p biomechanics concepts. Students' confidence when encountering difficult biomechanics concepts was also significantly (p biomechanics and confidence in solving relevant professional problems in order to improve learning for both low- and high-ability students.

Quantitative methods for reconstructing tissue biomechanical properties in optical coherence elastography: a comparison study

International Nuclear Information System (INIS)

Han, Zhaolong; Li, Jiasong; Singh, Manmohan; Wu, Chen; Liu, Chih-hao; Wang, Shang; Idugboe, Rita; Raghunathan, Raksha; Sudheendran, Narendran; Larin, Kirill V; Aglyamov, Salavat R; Twa, Michael D

2015-01-01

We present a systematic analysis of the accuracy of five different methods for extracting the biomechanical properties of soft samples using optical coherence elastography (OCE). OCE is an emerging noninvasive technique, which allows assessment of biomechanical properties of tissues with micrometer spatial resolution. However, in order to accurately extract biomechanical properties from OCE measurements, application of a proper mechanical model is required. In this study, we utilize tissue-mimicking phantoms with controlled elastic properties and investigate the feasibilities of four available methods for reconstructing elasticity (Young’s modulus) based on OCE measurements of an air-pulse induced elastic wave. The approaches are based on the shear wave equation (SWE), the surface wave equation (SuWE), Rayleigh-Lamb frequency equation (RLFE), and finite element method (FEM), Elasticity values were compared with uniaxial mechanical testing. The results show that the RLFE and the FEM are more robust in quantitatively assessing elasticity than the other simplified models. This study provides a foundation and reference for reconstructing the biomechanical properties of tissues from OCE data, which is important for the further development of noninvasive elastography methods. (paper)

Relapse and stability of surgically assisted rapid maxillary expansion, an anatomical biomechanical study

NARCIS (Netherlands)

Koudstaal, M.J.; Smeets, J.B.J.; Kleinrensink, G.J.; Schulten, A.J.M.; van der Wal, K.G.H.

2009-01-01

Purpose: This anatomic biomechanical study was undertaken to gain insight into the underlining mechanism of tipping of the maxillary segments during transverse expansion using tooth-borne and bone-borne distraction devices. Materials and Methods: An anatomic biomechanical study was performed on 10

Qualitative biomechanical principles for application in coaching.

Science.gov (United States)

Knudson, Duane

2007-01-01

Many aspects of human movements in sport can be readily understood by Newtonian rigid-body mechanics. Many of these laws and biomechanical principles, however, are counterintuitive to a lot of people. There are also several problems in the application of biomechanics to sports, so the application of biomechanics in the qualitative analysis of sport skills by many coaches has been limited. Biomechanics scholars have long been interested in developing principles that facilitate the qualitative application of biomechanics to improve movement performance and reduce the risk of injury. This paper summarizes the major North American efforts to establish a set of general biomechanical principles of movement, and illustrates how principles can be used to improve the application of biomechanics in the qualitative analysis of sport technique. A coach helping a player with a tennis serve is presented as an example. The standardization of terminology for biomechanical principles is proposed as an important first step in improving the application ofbiomechanics in sport. There is also a need for international cooperation and research on the effectiveness of applying biomechanical principles in the coaching of sport techniques.

Role of Aquaporin 0 in lens biomechanics.

Science.gov (United States)

Sindhu Kumari, S; Gupta, Neha; Shiels, Alan; FitzGerald, Paul G; Menon, Anil G; Mathias, Richard T; Varadaraj, Kulandaiappan

2015-07-10

Maintenance of proper biomechanics of the eye lens is important for its structural integrity and for the process of accommodation to focus near and far objects. Several studies have shown that specialized cytoskeletal systems such as the beaded filament (BF) and spectrin-actin networks contribute to mammalian lens biomechanics; mutations or deletion in these proteins alters lens biomechanics. Aquaporin 0 (AQP0), which constitutes ∼45% of the total membrane proteins of lens fiber cells, has been shown to function as a water channel and a structural cell-to-cell adhesion (CTCA) protein. Our recent ex vivo study on AQP0 knockout (AQP0 KO) mouse lenses showed the CTCA function of AQP0 could be crucial for establishing the refractive index gradient. However, biomechanical studies on the role of AQP0 are lacking. The present investigation used wild type (WT), AQP5 KO (AQP5(-/-)), AQP0 KO (heterozygous KO: AQP0(+/-); homozygous KO: AQP0(-/-); all in C57BL/6J) and WT-FVB/N mouse lenses to learn more about the role of fiber cell AQPs in lens biomechanics. Electron microscopic images exhibited decreases in lens fiber cell compaction and increases in extracellular space due to deletion of even one allele of AQP0. Biomechanical assay revealed that loss of one or both alleles of AQP0 caused a significant reduction in the compressive load-bearing capacity of the lenses compared to WT lenses. Conversely, loss of AQP5 did not alter the lens load-bearing ability. Compressive load-bearing at the suture area of AQP0(+/-) lenses showed easy separation while WT lens suture remained intact. These data from KO mouse lenses in conjunction with previous studies on lens-specific BF proteins (CP49 and filensin) suggest that AQP0 and BF proteins could act co-operatively in establishing normal lens biomechanics. We hypothesize that AQP0, with its prolific expression at the fiber cell membrane, could provide anchorage for cytoskeletal structures like BFs and together they help to confer

Interference screw versus Endoscrew fixation for anterior cruciate ligament reconstruction: A biomechanical comparative study in sawbones and porcine knees

Directory of Open Access Journals (Sweden)

Chu-Chih Hung

2014-04-01

Full Text Available Interference screw fixation is one of the most common methods for ligament reconstruction. Although the advantages and clinical outcomes of this procedure have been widely reported, post-surgical complications often arise. The purpose of this study was to evaluate a new femoral fixation device, the Endoscrew, for anterior cruciate ligament (ACL reconstruction. We performed a mechanical test in accordance with American Society for Testing and Materials (ASTM standards and an in vitro biomechanical study. An axial pullout test was conducted to evaluate the mechanical properties of the new device and the interference screw when implanted in solid rigid polyurethane foam test blocks. The biomechanical test used porcine femora to evaluate the initial fixation strength between these two implants. The maximum pullout force of the interference screw group [722.05 ± 130.49 N (N] was significantly greater (p < 0.01 than the Endoscrew group (440.79 ± 26.54 N when implanted in polyurethane foam 320 kg/m3 density. With polyurethane foam 160 kg/m3 density, the maximum pullout forces were (242.61 ± 37.36 N (p < 0.001 and (99.33 ± 30.01 N for the interference screw group and Endoscrew group, respectively. In the in vitro mechanical study, the Endoscrew (646.39 ± 72.38 N required a significantly greater ultimate load prior to failure (p < 0.05 when compared with the interference screw (489.72 ± 138.64 N. With regard to pullout stiffness, there was no statistically significant difference (p < 0.13 between the Endoscrew group (99.15 ± 12.16 N/mm and the interference screw group (87.96 ± 11.12 N/mm. The cyclic stiffness was also not significantly different (p < 0.44 between the Endoscrew group (93.09 ± 16.07 N/mm and the interference screw group (85.78 ± 14.76 N/mm. The axial pullout test showed that the strength of the Endoscrew was close to the fixation strength required for daily activities, but it is

Role of Aquaporin 0 in lens biomechanics

Energy Technology Data Exchange (ETDEWEB)

Sindhu Kumari, S.; Gupta, Neha [Physiology and Biophysics, Stony Brook University, Stony Brook, NY (United States); Shiels, Alan [Washington University School of Medicine, St. Louis, MO (United States); FitzGerald, Paul G. [Cell Biology and Human Anatomy, School of Medicine, University of California, Davis, CA (United States); Menon, Anil G. [University of Cincinnati College of Medicine, Cincinnati, OH (United States); Mathias, Richard T. [Physiology and Biophysics, Stony Brook University, Stony Brook, NY (United States); SUNY Eye Institute, NY (United States); Varadaraj, Kulandaiappan, E-mail: kulandaiappan.varadaraj@stonybrook.edu [Physiology and Biophysics, Stony Brook University, Stony Brook, NY (United States); SUNY Eye Institute, NY (United States)

2015-07-10

Maintenance of proper biomechanics of the eye lens is important for its structural integrity and for the process of accommodation to focus near and far objects. Several studies have shown that specialized cytoskeletal systems such as the beaded filament (BF) and spectrin-actin networks contribute to mammalian lens biomechanics; mutations or deletion in these proteins alters lens biomechanics. Aquaporin 0 (AQP0), which constitutes ∼45% of the total membrane proteins of lens fiber cells, has been shown to function as a water channel and a structural cell-to-cell adhesion (CTCA) protein. Our recent ex vivo study on AQP0 knockout (AQP0 KO) mouse lenses showed the CTCA function of AQP0 could be crucial for establishing the refractive index gradient. However, biomechanical studies on the role of AQP0 are lacking. The present investigation used wild type (WT), AQP5 KO (AQP5{sup −/−}), AQP0 KO (heterozygous KO: AQP0{sup +/−}; homozygous KO: AQP0{sup −/−}; all in C57BL/6J) and WT-FVB/N mouse lenses to learn more about the role of fiber cell AQPs in lens biomechanics. Electron microscopic images exhibited decreases in lens fiber cell compaction and increases in extracellular space due to deletion of even one allele of AQP0. Biomechanical assay revealed that loss of one or both alleles of AQP0 caused a significant reduction in the compressive load-bearing capacity of the lenses compared to WT lenses. Conversely, loss of AQP5 did not alter the lens load-bearing ability. Compressive load-bearing at the suture area of AQP0{sup +/−} lenses showed easy separation while WT lens suture remained intact. These data from KO mouse lenses in conjunction with previous studies on lens-specific BF proteins (CP49 and filensin) suggest that AQP0 and BF proteins could act co-operatively in establishing normal lens biomechanics. We hypothesize that AQP0, with its prolific expression at the fiber cell membrane, could provide anchorage for cytoskeletal structures like BFs and

Role of Aquaporin 0 in lens biomechanics

International Nuclear Information System (INIS)

Sindhu Kumari, S.; Gupta, Neha; Shiels, Alan; FitzGerald, Paul G.; Menon, Anil G.; Mathias, Richard T.; Varadaraj, Kulandaiappan

2015-01-01

Maintenance of proper biomechanics of the eye lens is important for its structural integrity and for the process of accommodation to focus near and far objects. Several studies have shown that specialized cytoskeletal systems such as the beaded filament (BF) and spectrin-actin networks contribute to mammalian lens biomechanics; mutations or deletion in these proteins alters lens biomechanics. Aquaporin 0 (AQP0), which constitutes ∼45% of the total membrane proteins of lens fiber cells, has been shown to function as a water channel and a structural cell-to-cell adhesion (CTCA) protein. Our recent ex vivo study on AQP0 knockout (AQP0 KO) mouse lenses showed the CTCA function of AQP0 could be crucial for establishing the refractive index gradient. However, biomechanical studies on the role of AQP0 are lacking. The present investigation used wild type (WT), AQP5 KO (AQP5 −/− ), AQP0 KO (heterozygous KO: AQP0 +/− ; homozygous KO: AQP0 −/− ; all in C57BL/6J) and WT-FVB/N mouse lenses to learn more about the role of fiber cell AQPs in lens biomechanics. Electron microscopic images exhibited decreases in lens fiber cell compaction and increases in extracellular space due to deletion of even one allele of AQP0. Biomechanical assay revealed that loss of one or both alleles of AQP0 caused a significant reduction in the compressive load-bearing capacity of the lenses compared to WT lenses. Conversely, loss of AQP5 did not alter the lens load-bearing ability. Compressive load-bearing at the suture area of AQP0 +/− lenses showed easy separation while WT lens suture remained intact. These data from KO mouse lenses in conjunction with previous studies on lens-specific BF proteins (CP49 and filensin) suggest that AQP0 and BF proteins could act co-operatively in establishing normal lens biomechanics. We hypothesize that AQP0, with its prolific expression at the fiber cell membrane, could provide anchorage for cytoskeletal structures like BFs and together they help to

An in vitro biomechanical comparison of anterior cruciate ligament reconstruction: single bundle versus anatomical double bundle techniques

Directory of Open Access Journals (Sweden)

Sandra Umeda Sasaki

2008-01-01

Full Text Available INTRODUCTION: Anterior cruciate ligament ruptures are frequent, especially in sports. Surgical reconstruction with autologous grafts is widely employed in the international literature. Controversies remain with respect to technique variations as continuous research for improvement takes place. One of these variations is the anatomical double bundle technique, which is performed instead of the conventional single bundle technique. More recently, there has been a tendency towards positioning the two bundles through double bone tunnels in the femur and tibia (anatomical reconstruction. OBJECTIVES: To compare, through biomechanical tests, the practice of anatomical double bundle anterior cruciate ligament reconstruction with a patellar graft to conventional single bundle reconstruction with the same amount of patellar graft in a paired experimental cadaver study. METHODS: Nine pairs of male cadaver knees ranging in age from 44 to 63 years were randomized into two groups: group A (single bundle and group B (anatomical reconstruction. Each knee was biomechanically tested under three conditions: intact anterior cruciate ligament, reconstructed anterior cruciate ligament, and injured anterior cruciate ligament. Maximum anterior dislocation, rigidity, and passive internal tibia rotation were recorded with knees submitted to a 100 N horizontal anterior dislocation force applied to the tibia with the knees at 30, 60 and 90 degrees of flexion. RESULTS: There were no differences between the two techniques for any of the measurements by ANOVA tests. CONCLUSION: The technique of anatomical double bundle reconstruction of the anterior cruciate ligament with bone-patellar tendon-bone graft has a similar biomechanical behavior with regard to anterior tibial dislocation, rigidity, and passive internal tibial rotation.

The effect of tendon loading on in-vitro carpal kinematics of the wrist joint

NARCIS (Netherlands)

Foumani, M.; Blankevoort, L.; Stekelenburg, C.; Strackee, S. D.; Carelsen, B.; Jonges, R.; Streekstra, G. J.

2010-01-01

Measurements of in-vitro carpal kinematics of the wrist provide valuable biomechanical data. Tendon loading is often applied during cadaver experiments to simulate natural stabilizing joint compression in the wrist joint. The purpose of this study was to investigate the effect of tendon loading on

An in vitro biomechanical comparison of equine proximal interphalangeal joint arthrodesis techniques: an axial positioned dynamic compression plate and two abaxial transarticular cortical screws inserted in lag fashion versus three parallel transarticular cortical screws inserted in lag fashion.

Science.gov (United States)

Sod, Gary A; Riggs, Laura M; Mitchell, Colin F; Hubert, Jeremy D; Martin, George S

2010-01-01

To compare in vitro monotonic biomechanical properties of an axial 3-hole, 4.5 mm narrow dynamic compression plate (DCP) using 5.5 mm cortical screws in conjunction with 2 abaxial transarticular 5.5 mm cortical screws inserted in lag fashion (DCP-TLS) with 3 parallel transarticular 5.5 mm cortical screws inserted in lag fashion (3-TLS) for the equine proximal interphalangeal (PIP) joint arthrodesis. Paired in vitro biomechanical testing of 2 methods of stabilizing cadaveric adult equine forelimb PIP joints. Cadaveric adult equine forelimbs (n=15 pairs). For each forelimb pair, 1 PIP joint was stabilized with an axial 3-hole narrow DCP (4.5 mm) using 5.5 mm cortical screws in conjunction with 2 abaxial transarticular 5.5 mm cortical screws inserted in lag fashion and 1 with 3 parallel transarticular 5.5 mm cortical screws inserted in lag fashion. Five matching pairs of constructs were tested in single cycle to failure under axial compression, 5 construct pairs were tested for cyclic fatigue under axial compression, and 5 construct pairs were tested in single cycle to failure under torsional loading. Mean values for each fixation method were compared using a paired t-test within each group with statistical significance set at Pcycle to failure, of the DCP-TLS fixation were significantly greater than those of the 3-TLS fixation. Mean cycles to failure in axial compression of the DCP-TLS fixation was significantly greater than that of the 3-TLS fixation. The DCP-TLS was superior to the 3-TLS in resisting the static overload forces and in resisting cyclic fatigue. The results of this in vitro study may provide information to aid in the selection of a treatment modality for arthrodesis of the equine PIP joint.

Multiscale modeling in biomechanics and mechanobiology

CERN Document Server

Hwang, Wonmuk; Kuhl, Ellen

2015-01-01

Presenting a state-of-the-art overview of theoretical and computational models that link characteristic biomechanical phenomena, this book provides guidelines and examples for creating multiscale models in representative systems and organisms. It develops the reader's understanding of and intuition for multiscale phenomena in biomechanics and mechanobiology, and introduces a mathematical framework and computational techniques paramount to creating predictive multiscale models.   Biomechanics involves the study of the interactions of physical forces with biological systems at all scales – including molecular, cellular, tissue and organ scales. The emerging field of mechanobiology focuses on the way that cells produce and respond to mechanical forces – bridging the science of mechanics with the disciplines of genetics and molecular biology. Linking disparate spatial and temporal scales using computational techniques is emerging as a key concept in investigating some of the complex problems underlying these...

Growth factor release by vesicular phospholipid gels: in-vitro results and application for rotator cuff repair in a rat model.

Science.gov (United States)

Buchmann, Stefan; Sandmann, Gunther H; Walz, Lars; Reichel, Thomas; Beitzel, Knut; Wexel, Gabriele; Tian, Weiwei; Battmann, Achim; Vogt, Stephan; Winter, Gerhard; Imhoff, Andreas B

2015-04-10

Biological augmentation of rotator cuff repair is of growing interest to improve biomechanical properties and prevent re-tearing. But intraoperative single shot growth factor application appears not sufficient to provide healing support in the physiologic growth factor expression peaks. The purpose of this study was to establish a sustained release of granulocyte-colony stimulating factor (G-CSF) from injectable vesicular phospholipid gels (VPGs) in vitro and to examine biocompatibility and influence on histology and biomechanical behavior of G-CSF loaded VPGs in a chronic supraspinatus tear rat model. G-CSF loaded VPGs were produced by dual asymmetric centrifugation. In vitro the integrity, stability and release rate were analyzed. In vivo supraspinatus tendons of 60 rats were detached and after 3 weeks a transosseous refixation with G-CSF loaded VPGs augmentation (n = 15; control, placebo, 1 and 10 μg G-CSF/d) was performed. 6 weeks postoperatively the healing site was analyzed histologically (n = 9; H&E by modified MOVIN score/Collagen I/III) and biomechanically (n = 6). In vitro testing revealed stable proteins after centrifugation and a continuous G-CSF release of up to 4 weeks. Placebo VPGs showed histologically no negative side effects on the healing process. Histologically in vivo testing demonstrated significant advantages for G-CSF 1 μg/d but not for G-CSF 10 μg/d in Collagen III content (p = 0.035) and a higher Collagen I/III ratio compared to the other groups. Biomechanically G-CSF 1 μg/d revealed a significant higher load to failure ratio (p = 0.020) compared to control but no significant differences in stiffness. By use of VPGs a continuous growth factor release could be obtained in vitro. The in vivo results demonstrate an improvement of immunohistology and biomechanical properties with a low dose G-CSF application via VPG. The VPG itself was well tolerated and had no negative influence on the healing behavior. Due to the favorable properties

Developments in dynamic MR elastography for in vitro biomechanical assessment of hyaline cartilage under high-frequency cyclical shear.

Science.gov (United States)

Lopez, Orlando; Amrami, Kimberly K; Manduca, Armando; Rossman, Phillip J; Ehman, Richard L

2007-02-01

The design, construction, and evaluation of a customized dynamic magnetic resonance elastography (MRE) technique for biomechanical assessment of hyaline cartilage in vitro are described. For quantification of the dynamic shear properties of hyaline cartilage by dynamic MRE, mechanical excitation and motion sensitization were performed at frequencies in the kilohertz range. A custom electromechanical actuator and a z-axis gradient coil were used to generate and image shear waves throughout cartilage at 1000-10,000 Hz. A radiofrequency (RF) coil was also constructed for high-resolution imaging. The technique was validated at 4000 and 6000 Hz by quantifying differences in shear stiffness between soft ( approximately 200 kPa) and stiff ( approximately 300 kPa) layers of 5-mm-thick bilayered phantoms. The technique was then used to quantify the dynamic shear properties of bovine and shark hyaline cartilage samples at frequencies up to 9000 Hz. The results demonstrate that one can obtain high-resolution shear stiffness measurements of hyaline cartilage and small, stiff, multilayered phantoms at high frequencies by generating robust mechanical excitations and using large magnetic field gradients. Dynamic MRE can potentially be used to directly quantify the dynamic shear properties of hyaline and articular cartilage, as well as other cartilaginous materials and engineered constructs. (c) 2007 Wiley-Liss, Inc.

Why National Biomechanics Day?

Science.gov (United States)

DeVita, Paul

2018-04-11

National Biomechanics Day (NBD) seeks to expand the influence and impact of Biomechanics on our society by expanding the awareness of Biomechanics among young people. NBD will manifest this goal through worldwide, synchronized and coordinated celebrations and demonstrations of all things Biomechanics with high school students. NBD invites all Biomechanists to participate in NBD 2018, http://nationalbiomechanicsday.asbweb.org/. Copyright © 2018 Elsevier Ltd. All rights reserved.

Energetics, Biomechanics, and Performance in Masters' Swimmers: A Systematic Review.

Science.gov (United States)

Ferreira, Maria I; Barbosa, Tiago M; Costa, Mário J; Neiva, Henrique P; Marinho, Daniel A

2016-07-01

Ferreira, MI, Barbosa, TM, Costa, MJ, Neiva, HP, and Marinho, DA. Energetics, biomechanics, and performance in masters' swimmers: a systematic review. J Strength Cond Res 30(7): 2069-2081, 2016-This study aimed to summarize evidence on masters' swimmers energetics, biomechanics, and performance gathered in selected studies. An expanded search was conducted on 6 databases, conference proceedings, and department files. Fifteen studies were selected for further analysis. A qualitative evaluation of the studies based on the Quality Index (QI) was performed by 2 independent reviewers. The studies were thereafter classified into 3 domains according to the reported data: performance (10 studies), energetics (4 studies), and biomechanics (6 studies). The selected 15 articles included in this review presented low QI scores (mean score, 10.47 points). The biomechanics domain obtained higher QI (11.5 points), followed by energetics and performance (10.6 and 9.9 points, respectively). Stroke frequency (SF) and stroke length (SL) were both influenced by aging, although SF is more affected than SL. Propelling efficiency (ηp) decreased with age. Swimming performance declined with age. The performance declines with age having male swimmers deliver better performances than female counterparts, although this difference tends to be narrow in long-distance events. One single longitudinal study is found in the literature reporting the changes in performance over time. The remaining studies are cross-sectional designs focusing on the energetics and biomechanics. Overall, biomechanics parameters, such as SF, SL, and ηp, tend to decrease with age. This review shows the lack of a solid body of knowledge (reflected in the amount and quality of the articles published) on the changes in biomechanics, energetics, and performance of master swimmers over time. The training programs for this age-group should aim to preserve the energetics as much as possible and, concurrently, improve the

Brillouin microscopy: assessing ocular tissue biomechanics.

Science.gov (United States)

Yun, Seok Hyun; Chernyak, Dimitri

2018-07-01

Assessment of corneal biomechanics has been an unmet clinical need in ophthalmology for many years. Many researchers and clinicians have identified corneal biomechanics as source of variability in refractive procedures and one of the main factors in keratoconus. However, it has been difficult to accurately characterize corneal biomechanics in patients. The recent development of Brillouin light scattering microscopy heightens the promise of bringing biomechanics into the clinic. The aim of this review is to overview the progress and discuss prospective applications of this new technology. Brillouin microscopy uses a low-power near-infrared laser beam to determine longitudinal modulus or mechanical compressibility of tissue by analyzing the return signal spectrum. Human clinical studies have demonstrated significant difference in the elastic properties of normal corneas versus corneas diagnosed with mild and severe keratoconus. Clinical data have also shown biomechanical changes after corneal cross-linking treatment of keratoconus patients. Brillouin measurements of the crystalline lens and sclera have also been demonstrated. Brillouin microscopy is a promising technology under commercial development at present. The technique enables physicians to characterize the biomechanical properties of ocular tissues.

Invertebrate biomechanics.

Science.gov (United States)

Patek, S N; Summers, A P

2017-05-22

Invertebrate biomechanics focuses on mechanical analyses of non-vertebrate animals, which at root is no different in aim and technique from vertebrate biomechanics, or for that matter the biomechanics of plants and fungi. But invertebrates are special - they are fabulously diverse in form, habitat, and ecology and manage this without the use of hard, internal skeletons. They are also numerous and, in many cases, tractable in an experimental and field setting. In this Primer, we will probe three axes of invertebrate diversity: worms (Phylum Annelida), spiders (Class Arachnida) and insects (Class Insecta); three habitats: subterranean, terrestrial and airborne; and three integrations with other fields: ecology, engineering and evolution. Our goal is to capture the field of invertebrate biomechanics, which has blossomed from having a primary focus on discoveries at the interface of physics and biology to being inextricably linked with integrative challenges that span biology, physics, mathematics and engineering. Copyright © 2017 Elsevier Ltd. All rights reserved.

Arch index and running biomechanics in children aged 10-14 years.

Science.gov (United States)

Hollander, Karsten; Stebbins, Julie; Albertsen, Inke Marie; Hamacher, Daniel; Babin, Kornelia; Hacke, Claudia; Zech, Astrid

2018-03-01

While altered foot arch characteristics (high or low) are frequently assumed to influence lower limb biomechanics and are suspected to be a contributing factor for injuries, the association between arch characteristics and lower limb running biomechanics in children is unclear. Therefore, the aim of this study was to investigate the relationship between a dynamically measured arch index and running biomechanics in healthy children. One hundred and one children aged 10-14 years were included in this study and underwent a biomechanical investigation. Plantar distribution (Novel, Emed) was used to determine the dynamic arch index and 3D motion capture (Vicon) to measure running biomechanics. Linear mixed models were established to determine the association between dynamic arch index and foot strike patterns, running kinematics, kinetics and temporal-spatial outcomes. No association was found between dynamic arch index and rate of rearfoot strikes (p = 0.072). Of all secondary outcomes, only the foot progression angle was associated with the dynamic arch index (p = 0.032) with greater external rotation in lower arched children. Overall, we found only few associations between arch characteristics and running biomechanics in children. However, altered foot arch characteristics are of clinical interest. Future studies should focus on detailed foot biomechanics and include clinically diagnosed high and low arched children. Copyright © 2018 Elsevier B.V. All rights reserved.

Mystery of alar ligament rupture: Value of MRI in whiplash injuries - biomechanical, anatomical and clinical studies

International Nuclear Information System (INIS)

Bitterling, H.; Brueckmann, H.; Staebler, A.

2007-01-01

Purpose: Whiplash injury of the cervical spine is a frequent issue in medical expertise and causes enormous consequential costs for motor insurance companies. Some authors accuse posttraumatic changes of alar ligaments to be causative for consequential disturbances. Materials and methods: Review of recent studies on biomechanics, anatomical and clinical MR imaging. Results: Biomechanical experiments can not induce according injuries of alar ligaments. Although MRI provides excellent visualization of alar ligaments, the range of normal variants is high. (orig.)

The effect of tibial plateau leveling osteotomy position on cranial tibial subluxation: an in vitro study.

Science.gov (United States)

Kowaleski, Michael P; Apelt, Detlef; Mattoon, John S; Litsky, Alan S

2005-01-01

To compare centered versus distal tibial plateau leveling osteotomy (TPLO) position on cranial tibial subluxation, postoperative tibial plateau angle (TPA), and tibial long axis shift (TLAS). In vitro biomechanical evaluation. Six pairs of canine cadaveric hind limbs. One limb of each pair was randomly assigned to the distal (TPLO-D) or centered (TPLO-C) osteotomy group. Cranial tibial subluxation (CTS) under load was quantified sequentially under 3 conditions: intact, after cranial cruciate ligament transection, and after TPLO; a corrected CTS value was also calculated. Postoperative TPA and TLAS were measured. Comparisons were made using 1-way repeated measures ANOVA with a Tukey's multiple comparison post hoc test for CTS, and a Wilcoxon's sign rank test for TPA and TLAS. Significance was set at Pcranial tibial thrust. The centered osteotomy position is geometrically more precise, and biomechanically more effective than the distal position.

Comparison of revision strategies for failed C2-posterior cervical pedicle screws: a biomechanical study.

Science.gov (United States)

Mayer, Michael; Zenner, Juliane; Bogner, Robert; Hitzl, Wolfgang; Figl, Markus; von Keudell, Arvind; Stephan, Daniel; Penzkofer, Rainer; Augat, Peter; Korn, Gundobert; Resch, Herbert; Koller, Heiko

2013-01-01

With increasing usage within challenging biomechanical constructs, failures of C2 posterior cervical pedicle screws (C2-pCPSs) will occur. The purpose of the study was therefore to investigate the biomechanical characteristics of two revision techniques after the failure of C2-pCPSs. Twelve human C2 vertebrae were tested in vitro in a biomechanical study to compare two strategies for revision screws after failure of C2-pCPSs. C2 pedicles were instrumented using unicortical 3.5-mm CPS bilaterally (Synapse/Synthes, Switzerland). Insertion accuracy was verified by fluoroscopy. C2 vertebrae were potted and fixed in an electromechanical testing machine with the screw axis coaxial to the pullout direction. Pullout testing was conducted with load and displacement data taken continuously. The peak load to failure was measured in newtons (N) and is reported as the pullout resistance (POR). After pullout, two revision strategies were tested in each vertebra. In Group-1, revision was performed with 4.0-mm C2-pCPSs. In Group-2, revision was performed with C2-pedicle bone-plastic combined with the use of a 4-mm C2-pCPSs. For the statistical analysis, the POR between screws was compared using absolute values (N) and the POR of the revision techniques normalized to that of the primary procedures (%). The POR of primary 3.5-mm CPSs was 1,140.5 ± 539.6 N for Group-1 and 1,007.7 ± 362.5 N for Group-2; the difference was not significant. In the revision setting, the POR in Group-1 was 705.8 ± 449.1 N, representing a reduction of 38.1 ± 32.9 % compared with that of primary screw fixation. For Group-2, the POR was 875.3 ± 367.9 N, representing a reduction of 13.1 ± 23.4 %. A statistical analysis showed a significantly higher POR for Group-2 compared with Group-1 (p = 0.02). Although the statistics showed a significantly reduced POR for both revision strategies compared with primary fixation (p plastic, the POR can be significantly increased compared with the use of only an

In vitro and biomechanical screening of polyethylene glycol and poly(trimethylene carbonate) block copolymers for annulus fibrosus repair.

Science.gov (United States)

Long, Rose G; Rotman, Stijn G; Hom, Warren W; Assael, Dylan J; Illien-Jünger, Svenja; Grijpma, Dirk W; Iatridis, James C

2018-02-01

Herniated intervertebral discs (IVDs) are a common cause of back and neck pain. There is an unmet clinical need to seal annulus fibrosus (AF) defects, as discectomy surgeries address acute pain but are complicated by reherniation and recurrent pain. Copolymers of polyethylene glycol with trimethylene carbonate (TMC) and hexamethylene diisocyanate (HDI) end-groups were formulated as AF sealants as the HDI form covalent bonds with native AF tissue. TMC adhesives were evaluated and optimized using the design criteria: stable size, strong adherence to AF tissue, high cytocompatibility, restoration of IVD biomechanics to intact levels following in situ repair, and low extrusion risk. TMC adhesives had high adhesion strength as assessed with a pushout test (150 kPa), and low degradation rates over 3 weeks in vitro. Both TMC adhesives had shear moduli (220 and 490 kPa) similar to, but somewhat higher than, AF tissue. The adhesive with three TMC moieties per branch (TMC3) was selected for additional in situ testing because it best matched AF shear properties. TMC3 restored torsional stiffness, torsional hysteresis area and axial range of motion to intact states. However, in a failure test of compressive deformation under fixed 5 ° flexion, some herniation risk was observed with failure strength of 5.9 MPa compared with 13.5 MPa for intact samples; TMC3 herniated under cyclic organ culture testing. These TMC adhesives performed well during in vitro and in situ testing, but additional optimization to enhance failure strength is required to further this material to advanced screening tests, such as long-term degradation. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

[RESEARCH PROGRESS OF BIOMECHANICS OF PROXIMAL ROW CARPAL INSTABILITY].

Science.gov (United States)

Guo, Jinhai; Huang, Fuguo

2015-01-01

To review the research progress of the biomechanics of proximal row carpal instability (IPRC). The related literature concerning IPRC was extensively reviewed. The biomechanical mechanism of the surrounding soft tissue in maintaining the stability of the proximal row carpal (PRC) was analyzed, and the methods to repair or reconstruct the stability and function of the PRC were summarized from two aspects including basic biomechanics and clinical biomechanics. The muscles and ligaments of the PRC are critical to its stability. Most scholars have reached a consensus about biomechanical mechanism of the PRC, but there are still controversial conclusions on the biomechanics mechanism of the surrounding soft tissue to stability of distal radioulnar joint when the triangular fibrocartilage complex are damaged and the biomechanics mechanism of the scapholunate ligament. At present, there is no unified standard about the methods to repair or reconstruct the stability and function of the PRC. So, it is difficult for clinical practice. Some strides have been made in the basic biomechanical study on muscle and ligament and clinical biomechanical study on the methods to repair or reconstruct the stability and function of PRC, but it will be needed to further study the morphology of carpal articular surface and the adjacent articular surface, the pressure of distal carpals to proximal carpal and so on.

Biological variability in biomechanical engineering research: Significance and meta-analysis of current modeling practices.

Science.gov (United States)

Cook, Douglas; Julias, Margaret; Nauman, Eric

2014-04-11

Biological systems are characterized by high levels of variability, which can affect the results of biomechanical analyses. As a review of this topic, we first surveyed levels of variation in materials relevant to biomechanics, and compared these values to standard engineered materials. As expected, we found significantly higher levels of variation in biological materials. A meta-analysis was then performed based on thorough reviews of 60 research studies from the field of biomechanics to assess the methods and manner in which biological variation is currently handled in our field. The results of our meta-analysis revealed interesting trends in modeling practices, and suggest a need for more biomechanical studies that fully incorporate biological variation in biomechanical models and analyses. Finally, we provide some case study example of how biological variability may provide valuable insights or lead to surprising results. The purpose of this study is to promote the advancement of biomechanics research by encouraging broader treatment of biological variability in biomechanical modeling. Copyright © 2014 Elsevier Ltd. All rights reserved.

Gingival Recessions and Biomechanics

DEFF Research Database (Denmark)

Laursen, Morten Godtfredsen

Gingival recessions and biomechanics “Tissue is the issue, but bone sets the tone.“ A tooth outside the cortical plate can result in loss of bone and development of a gingival recession. The presentation aims to show biomechanical considerations in relation to movement of teeth with gingival...... by moving the root back in the alveolus. The tooth movement is accompanied by bone gain and thus increase the success rate for soft tissue augmentation. The choice of biomechanical system influences the treatment outcome. If a standard straight wire appliance is used, a biomechanical dilemma can arise...

Intestinal morphometric and biomechanical changes during aging in rats

DEFF Research Database (Denmark)

Zhao, Jingbo; Gregersen, Hans

2015-01-01

Background and aim: Previously we demonstrated pronounced morphometric and biomechanical remodeling in the rat intestine during physiological growth up to 32 weeks of age. The aim of the present study is to study intestinal geometric and biomechanical changes in aging rats. Materials and methods...... in the circumferential direction. In conclusion pronounced morphometric and biomechanical remodeling occurred in the rat intestine during aging. The observed changes likely reflect the changes of the physiological function of the intestine during ageing, similar to other tissues where function, mechanical loading......: Twenty-four male Wistar rats, aged from 6 to 22 months, were used in the study. The body weight and the wet weight per length of duodenal and ileal segments were measured at the termination of experiment. Morphometric data were obtained by measuring the wall thickness and wall cross-sectional area...

Integrative Role Of Cinematography In Biomechanics Research

Science.gov (United States)

Zernicke, Ronald F.; Gregor, Robert J.

1982-02-01

Cinematography is an integral element in the interdisciplinary biomechanics research conducted in the Department of Kinesiology at the University of California, Los Angeles. For either an isolated recording of a movement phenomenon or as a recording component which is synchronized with additional transducers and recording equipment, high speed motion picture film has been effectively incorporated into resr'arch projects ranging from two and three dimensional analyses of human movements, locomotor mechanics of cursorial mammals and primates, to the structural responses and dynamic geometries of skeletal muscles, tendons, and ligaments. The basic equipment used in these studies includes three, 16 mm high speed, pin-registered cameras which have the capacity for electronic phase-locking. Crystal oscillators provide the generator pulses to synchronize the timing lights of the cameras and the analog-to-digital recording equipment. A rear-projection system with a sonic digitizer permits quantification of film coordinates which are stored on computer disks. The capacity for synchronizing the high speed films with additional recording equipment provides an effective means of obtaining not only position-time data from film, but also electromyographic, force platform, tendon force transducer, and strain gauge recordings from tissues or moving organisms. During the past few years, biomechanics research which comprised human studies has used both planar and three-dimensional cinematographic techniques. The studies included planar analyses which range from the gait characteristics of lower extremity child amputees to the running kinematics and kinetics of highly skilled sprinters and long-distance runners. The dynamics of race cycling and kinetics of gymnastic maneuvers were studied with cinematography and either a multi-dimensional force platform or a bicycle pedal with strain gauges to determine the time histories of the applied forces. The three-dimensional technique

Poor relation between biomechanical and clinical studies for the proximal femoral locking compression plate

DEFF Research Database (Denmark)

Viberg, Bjarke; Voergård Rasmussen, Katrine Marie; Overgaard, Søren

2017-01-01

Background and purpose — The proximal femur locking compression plate (PF-LCP) is a new concept in the treatment of hip fractures. When releasing new implants onto the market, biomechanical studies are conducted to evaluate performance of the implant. We investigated the relation between biomecha......Background and purpose — The proximal femur locking compression plate (PF-LCP) is a new concept in the treatment of hip fractures. When releasing new implants onto the market, biomechanical studies are conducted to evaluate performance of the implant. We investigated the relation between...

Validation of an experimental polyurethane model for biomechanical studies on implant supported prosthesis - tension tests

Directory of Open Access Journals (Sweden)

Mariane Miyashiro

2011-06-01

Full Text Available OBJECTIVES: The complexity and heterogeneity of human bone, as well as ethical issues, frequently hinder the development of clinical trials. The purpose of this in vitro study was to determine the modulus of elasticity of a polyurethane isotropic experimental model via tension tests, comparing the results to those reported in the literature for mandibular bone, in order to validate the use of such a model in lieu of mandibular bone in biomechanical studies. MATERIAL AND METHODS: Forty-five polyurethane test specimens were divided into 3 groups of 15 specimens each, according to the ratio (A/B of polyurethane reagents (PU-1: 1/0.5, PU-2: 1/1, PU-3: 1/1.5. RESULTS: Tension tests were performed in each experimental group and the modulus of elasticity values found were 192.98 MPa (SD=57.20 for PU-1, 347.90 MPa (SD=109.54 for PU-2 and 304.64 MPa (SD=25.48 for PU-3. CONCLUSION: The concentration of choice for building the experimental model was 1/1.

Knee Biomechanics During Jogging After Arthroscopic Partial Meniscectomy: A Longitudinal Study.

Science.gov (United States)

Hall, Michelle; Wrigley, Tim V; Metcalf, Ben R; Hinman, Rana S; Cicuttini, Flavia M; Dempsey, Alasdair R; Lloyd, David G; Bennell, Kim L

2017-07-01

Altered knee joint biomechanics is thought to play a role in the pathogenesis of knee osteoarthritis and has been reported in patients after arthroscopic partial meniscectomy (APM) while performing various activities. Longitudinally, understanding knee joint biomechanics during jogging may assist future studies to assess the implications of jogging on knee joint health in this population. To investigate knee joint biomechanics during jogging in patients 3 months after APM and a healthy control group at baseline and 2 years later at follow-up. Controlled laboratory study. Seventy-eight patients who underwent medial APM and 38 healthy controls underwent a 3-dimensional motion analysis during barefoot overground jogging at baseline. Sixty-four patients who underwent APM and 23 controls returned at follow-up. External peak moments (flexion and adduction) and the peak knee flexion angle during stance were evaluated for the APM leg, non-APM leg (nonoperated leg), and control leg. At baseline, the peak knee flexion angle was 1.4° lower in the APM leg compared with the non-APM leg ( P = .03). No differences were found between the moments in the APM leg compared with the control leg (all P > .05). However, the normalized peak knee adduction moment was 35% higher in the non-APM leg compared with the control leg ( P = .008). In the non-APM leg, the normalized peak knee adduction and flexion moments were higher compared with the APM leg by 16% and 10%, respectively, at baseline ( P ≤ .004). Despite the increase in the peak knee flexion moment in the APM leg compared with the non-APM leg ( P .05). Comparing the APM leg and control leg, no differences in knee joint biomechanics during jogging for the variables assessed were observed. Higher knee moments in the non-APM leg may have clinical implications for the noninvolved leg. Kinematic differences were small (~1.4°) and therefore of questionable clinical relevance. These results may facilitate future clinical research

Computational biomechanics

International Nuclear Information System (INIS)

Ethier, C.R.

2004-01-01

Computational biomechanics is a fast-growing field that integrates modern biological techniques and computer modelling to solve problems of medical and biological interest. Modelling of blood flow in the large arteries is the best-known application of computational biomechanics, but there are many others. Described here is work being carried out in the laboratory on the modelling of blood flow in the coronary arteries and on the transport of viral particles in the eye. (author)

Biomechanics Associated with Patellofemoral Pain and ACL Injuries in Sports.

Science.gov (United States)

Weiss, Kaitlyn; Whatman, Chris

2015-09-01

Knee injuries are prevalent among a variety of competitive sports and can impact an athlete's ability to continue to participate in their sport or, in the worst case, end an athlete's career. The aim was to evaluate biomechanics associated with both patellofemoral pain syndrome (PFPS) and anterior cruciate ligament (ACL) injuries (in sports involving landing, change in direction, or rapid deceleration) across the three time points frequently reported in the literature: pre-injury, at the time of injury, and following injury. A search of the literature was conducted for research evaluating biomechanics associated with ACL injury and PFPS. The Web of Science, SPORTDiscus, EBSCO, PubMed, and CINAHL databases, to March 2015, were searched, and journal articles focused on ACL injuries and PFPS in sports that met the inclusion criteria were reviewed. The search methodology was created with the intent of extracting case-control, case, and cohort studies of knee injury in athletic populations. The search strategy was restricted to only full-text articles published in English. These articles were included in the review if they met all of the required selection criteria. The following inclusion criteria were used: (1) The study must report lower extremity biomechanics in one of the following settings: (a) a comparison of currently injured and uninjured participants, (b) a prospective study evaluating risk factors for injury, or (c) a study reporting on the injury event itself. (2) The study must include only currently active participants who were similar at baseline (i.e. healthy, high school level basketball players currently in-season) and include biomechanical analysis of either landing, change in direction, or rapid deceleration. (3) The study must include currently injured participants. The studies were graded on the basis of quality, which served as an indication of risk of bias. An adapted version of the 'Strengthening the Reporting of Observational Studies in

The biomechanical assessment of the cervical inter-vertebral kinematics, between DDD patients ICR based study

Science.gov (United States)

Saveh, Amir Hossein; Zali, Ali Reza; Seddighi, Amir Saeed; Zarghi, Afsaneh; Chizari, Mahmoud; Hanafiah, Yussof

2012-01-01

Abstract: It is very important to pay more attention to spine from the biomechanical perspective. It would allow the analysis of initial conditions of the vertebral disc degeneration syndrome and adopting of normal spine kinematics to compare and match it with a degenerated disc and providing a biomechanical index as an indicator for the conduct of any surgical intervention including arthroplasty to maximize restoring spinal biomechanical motion. It is clear that the head movement is possible with the help of muscles. However, the shape and type of motion depends on the structure and shape of the cervical spine and the interaction between them. Cervical spine kinematics depends on the anatomy of the bones and joints. Bazhdok et al (2000) investigated the cervical kinematics and mechanical behavior of the spine and its anatomical connections. They have examined the atlanto- occipital joint motion during flexion-extension and rotation as well as the mechanism of paradoxical motion of atlanto- axial joint by radiography. Bifalkou et al (2011) studied the inter-vertebral motion based on arc kinematic commentary of video fluoroscopy. They showed that the diagnosis of biomechanical instability can be done based on the kinematic examination of the spine obtained in sagittal images. They also declared that the fluoroscopy can be used as a tool for study. Using an automated algorithm, image adaption was carried out and the motion direction of vertebrae was tracked. In the present study, some patients were selected among patients with cervical disc degeneration. Following imaging by fluoroscopy, the instantaneous center of the spinal action was calculated. It was used as a biomechanical criterion and the treatment group was compared with the healthy group. The loci of the instantaneous centers of the two groups were compared and its difference with the value of healthy group was calculated. A biomechanical criterion was introduced as a basis for comparison of normal and

Biomechanical analysis of rollator walking

DEFF Research Database (Denmark)

Alkjaer, T; Larsen, Peter K; Pedersen, Gitte

2006-01-01

The rollator is a very popular walking aid. However, knowledge about how a rollator affects the walking patterns is limited. Thus, the purpose of the study was to investigate the biomechanical effects of walking with and without a rollator on the walking pattern in healthy subjects.......The rollator is a very popular walking aid. However, knowledge about how a rollator affects the walking patterns is limited. Thus, the purpose of the study was to investigate the biomechanical effects of walking with and without a rollator on the walking pattern in healthy subjects....

Biomechanical Remodeling of the Diabetic Gastrointestinal Tract

DEFF Research Database (Denmark)

Zhao, Jingbo; Liao, Donghua; Yang, Jian

2010-01-01

several years, several studies demonstrated that experimental diabetes induces GI morphological and biomechanical remodeling. Following the development of diabetes, the GI wall becomes thicker and the stiffness of the GI wall increases in a time-dependent manner. It is well known that mechanosensitive...... the biomechanical environment of the mechanosensitive nerve endings, therefore, the structure as well as the tension, stress and strain distribution in the GI wall is important for the sensory and motor function. Biomechanical remodeling of diabetic GI tract including alterations of residual strain and increase...

Optic nerve head biomechanics in aging and disease.

Science.gov (United States)

Downs, J Crawford

2015-04-01

This nontechnical review is focused upon educating the reader on optic nerve head biomechanics in both aging and disease along two main themes: what is known about how mechanical forces and the resulting deformations are distributed in the posterior pole and ONH (biomechanics) and what is known about how the living system responds to those deformations (mechanobiology). We focus on how ONH responds to IOP elevations as a structural system, insofar as the acute mechanical response of the lamina cribrosa is confounded with the responses of the peripapillary sclera, prelaminar neural tissues, and retrolaminar optic nerve. We discuss the biomechanical basis for IOP-driven changes in connective tissues, blood flow, and cellular responses. We use glaucoma as the primary framework to present the important aspects of ONH biomechanics in aging and disease, as ONH biomechanics, aging, and the posterior pole extracellular matrix (ECM) are thought to be centrally involved in glaucoma susceptibility, onset and progression. Copyright © 2015 Elsevier Ltd. All rights reserved.

Gait biomechanics in the era of data science.

Science.gov (United States)

Ferber, Reed; Osis, Sean T; Hicks, Jennifer L; Delp, Scott L

2016-12-08

Data science has transformed fields such as computer vision and economics. The ability of modern data science methods to extract insights from large, complex, heterogeneous, and noisy datasets is beginning to provide a powerful complement to the traditional approaches of experimental motion capture and biomechanical modeling. The purpose of this article is to provide a perspective on how data science methods can be incorporated into our field to advance our understanding of gait biomechanics and improve treatment planning procedures. We provide examples of how data science approaches have been applied to biomechanical data. We then discuss the challenges that remain for effectively using data science approaches in clinical gait analysis and gait biomechanics research, including the need for new tools, better infrastructure and incentives for sharing data, and education across the disciplines of biomechanics and data science. By addressing these challenges, we can revolutionize treatment planning and biomechanics research by capitalizing on the wealth of knowledge gained by gait researchers over the past decades and the vast, but often siloed, data that are collected in clinical and research laboratories around the world. Copyright © 2016 Elsevier Ltd. All rights reserved.

Computer simulation of human motion in sports biomechanics.

Science.gov (United States)

Vaughan, C L

1984-01-01

This chapter has covered some important aspects of the computer simulation of human motion in sports biomechanics. First the definition and the advantages and limitations of computer simulation were discussed; second, research on various sporting activities were reviewed. These activities included basic movements, aquatic sports, track and field athletics, winter sports, gymnastics, and striking sports. This list was not exhaustive and certain material has, of necessity, been omitted. However, it was felt that a sufficiently broad and interesting range of activities was chosen to illustrate both the advantages and the pitfalls of simulation. It is almost a decade since Miller [53] wrote a review chapter similar to this one. One might be tempted to say that things have changed radically since then--that computer simulation is now a widely accepted and readily applied research tool in sports biomechanics. This is simply not true, however. Biomechanics researchers still tend to emphasize the descriptive type of study, often unfortunately, when a little theoretical explanation would have been more helpful [29]. What will the next decade bring? Of one thing we can be certain: The power of computers, particularly the readily accessible and portable microcomputer, will expand beyond all recognition. The memory and storage capacities will increase dramatically on the hardware side, and on the software side the trend will be toward "user-friendliness." It is likely that a number of software simulation packages designed specifically for studying human motion [31, 96] will be extensively tested and could gain wide acceptance in the biomechanics research community. Nevertheless, a familiarity with Newtonian and Lagrangian mechanics, optimization theory, and computers in general, as well as practical biomechanical insight, will still be a prerequisite for successful simulation models of human motion. Above all, the biomechanics researcher will still have to bear in mind that

Comparative biomechanical study between fresh frozen bone and fresh frozen pasteurized bone process

International Nuclear Information System (INIS)

Ferdiansyah Abdurrahman

1999-01-01

To observe the biomechanical properties difference between fresh frozen bone and fresh frozen pasteurized bone process Thirty eight femurs bones taken from 6 years old primate.(macaca fascicularis) from Primate Nursery Center LIPI Bogor, 20 bones were 6 cm cut for bending test and 18 remains were 3 cm cut for compression test. All bones were frozen and then divided into two groups for each biomechanical study. First group (I 0 bones for bending test and 9 bones for compression test) were undergone fresh frozen procession only. The second group with the same amount was undergone fresh frozen and pasteurized on 60 degree C for three hours. Bending test was done until the bones were broken on control group and pasteurized group and the result was compared, the same procedure was done for compression test. The study was done in room temperature. The biomechanical test result was analyzed by two independent T tests. The bending test control group has ( mean 0.097 N / mm sup 2 (SD = 0.007) and the pasteurized group ( mean 0. I 0 1 N / mm sup 2 (SD = 0.0 1 3), there was no significant difference (p 0.399). The compression test control group has ( = mean 0.71 N / mm sup 2 (SD=0.128)where as the pasteurized group has(mean 0.50N/mm sup 2 (SD=0.111),there was significant difference (p =0.004) From the result biomechanical study on bending test, there was no significant difference of bone strength, whereas on compression test the fresh frozen with pasteurized bone group is 125% stronger than control group. The result of this study will be very useful for reconstruction bone allograft

Biomechanical analysis of titanium plate systems in mandibular condyle fractures: a systematized literature review Análise biomecânica de sistemas de placas de titânio em fraturas de côndilo mandibular: uma revisão sistematizada da literatura

Directory of Open Access Journals (Sweden)

Fábio Wildson Gurgel Costa

2012-06-01

Full Text Available PURPOSE: To conduct a systematized review of the literature about the main methodologies used to evaluate the biomechanical fixation systems with titanium plates in fractures of the mandibular condyle. METHODS: A systematized review of literature was performed in the electronic databases PubMed, EMBASE, LILACS and MEDLINE without restriction of the publication date. The eligibility criteria were laboratory studies involving mandibular condyle fractures, studies using titanium plates, biomechanical studies, in vitro and computational studies involving the finite element method (FEM. RESULTS: Eleven articles that met the eligibility criteria were selected, including seven articles involving in vitro studies and four studies with biomechanical analysis by using FEM. CONCLUSION: Although few articles have used the finite element method, the results of in vitro studies were similar to those found in computational studies, regarding to the stable use of two titanium miniplates.OBJETIVO: Realizar uma revisão sistematizada da literatura sobre as principais metodologias empregadas na avaliação biomecânica de sistemas de fixação com placas de titânio em fraturas de côndilo mandibular. MÉTODOS: Foi realizada uma revisão sistematizada da literatura nas bases de dados eletrônicas PubMed, EMBASE, LILACS e MEDLINE sem restrição quanto à data de publicação. Os critérios de elegibilidade foram estudos laboratoriais envolvendo fraturas de côndilo mandibular, estudos utilizando placas de titânio, estudos biomecânicos, estudos in vitro e estudos computacionais envolvendo o método de elementos finitos (MEF. RESULTADOS: Foram selecionados 11 artigos que se enquadraram nos critérios de elegibilidade, incluindo sete artigos envolvendo estudos in vitro e quatro utilizando análise biomecânica através do MEF. CONCLUSÃO: Embora poucos artigos tenham utilizado o método de elementos finitos, os resultados das pesquisas in vitro assemelham-se aos

Patch-augmented rotator cuff repair: influence of the patch fixation technique on primary biomechanical stability.

Science.gov (United States)

Jung, Christian; Spreiter, Gregor; Audigé, Laurent; Ferguson, Stephen J; Flury, Matthias

2016-05-01

There is an ongoing debate about the potential of patch augmentation to improve biomechanical stability and healing associated with rotator cuff repair. The biomechanical properties of three different patch-augmented rotator cuff repair techniques were assessed in vitro and compared with a standard repair. Dermal collagen patch augmentation may increase the primary stability and strength of the repaired tendon in vitro, depending on the technique used for patch application. Forty cadaveric sheep shoulders with dissected infraspinatus tendons were randomized into four groups (n = 10/group) for tendon repair using a knotless double-row suture anchor technique. A xenologous dermal extracellular matrix patch was used for augmentation in the three test groups using an "integrated", "cover", or "hybrid" technique. Tendons were preconditioned, cyclically loaded from 10 to 30 N at 1 Hz, and then loaded monotonically to failure. Biomechanical properties and the mode of failure were evaluated. Patch augmentation significantly increased the maximum load at failure by 61 % in the "cover" technique test group (225.8 N) and 51 % in the "hybrid" technique test group (211.4 N) compared with the non-augmented control group (140.2 N) (P ≤ 0.015). For the test group with "integrated" patch augmentation, the load at failure was 28 % lower (101.6 N) compared with the control group (P = 0.043). There was no significant difference in initial and linear stiffness among the four experimental groups. The most common mode of failure was tendon pullout. No anchor dislocation, patch disruption or knot breakage was observed. Additional patch augmentation with a collagen patch influences the biomechanical properties of a rotator cuff repair in a cadaveric sheep model. Primary repair stability can be significantly improved depending on the augmentation technique.

Biomechanics principles and practices

CERN Document Server

Peterson, Donald R

2014-01-01

Presents Current Principles and ApplicationsBiomedical engineering is considered to be the most expansive of all the engineering sciences. Its function involves the direct combination of core engineering sciences as well as knowledge of nonengineering disciplines such as biology and medicine. Drawing on material from the biomechanics section of The Biomedical Engineering Handbook, Fourth Edition and utilizing the expert knowledge of respected published scientists in the application and research of biomechanics, Biomechanics: Principles and Practices discusses the latest principles and applicat

The Influence of Artificial Cervical Disc Prosthesis Height on the Cervical Biomechanics: A Finite Element Study.

Science.gov (United States)

Yuan, Wei; Zhang, Haiping; Zhou, Xiaoshu; Wu, Weidong; Zhu, Yue

2018-05-01

Artificial cervical disc replacement is expected to maintain normal cervical biomechanics. At present, the effect of the Prestige LP prosthesis height on cervical biomechanics has not been thoroughly studied. This finite element study of the cervical biomechanics aims to predict how the parameters, like range of motion (ROM), adjacent intradiscal pressure, facet joint force, and bone-implant interface stress, are affected by different heights of Prestige LP prostheses. The finite element model of intact cervical spine (C3-C7) was obtained from our previous study, and the model was altered to implant Prestige LP prostheses at the C5-C6 level. The effects of the height of 5, 6, and 7 mm prosthesis replacement on ROM, adjacent intradiscal pressure, facet joint force, as well as the distribution of bone-implant interface stress were examined. ROM, adjacent intradiscal pressure, and facet joint force increased with the prosthesis height, whereas ROM and facet joint force decreased at C5-C6. The maximal stress on the inferior surface of the prostheses was greater than that on the superior surface, and the stresses increased with the prosthesis height. The biomechanical changes were slightly affected by the height of 5 and 6 mm prostheses, but were strongly affected by the 7-mm prosthesis. An appropriate height of the Prestige LP prosthesis can preserve normal ROM, adjacent intradiscal pressure, and facet joint force. Prostheses with a height of ≥2 mm than normal can lead to marked changes in the cervical biomechanics and bone-implant interface stress. Copyright © 2018 Elsevier Inc. All rights reserved.

A pilot study of biomechanical assessment before and after an integrative training program for adolescents with juvenile fibromyalgia.

Science.gov (United States)

Tran, Susan T; Thomas, Staci; DiCesare, Christopher; Pfeiffer, Megan; Sil, Soumitri; Ting, Tracy V; Williams, Sara E; Myer, Gregory D; Kashikar-Zuck, Susmita

2016-07-22

Adolescents with juvenile fibromyalgia (JFM) tend to be very sedentary and avoid participation in physical activity. A prior study suggested that JFM patients show altered biomechanics compared to healthy adolescents which may make them more prone to pain/injury during exercise. A new intervention combining well established cognitive behavioral therapy (CBT) techniques with specialized neuromuscular exercise -Fibromyalgia Integrative Training for Teens (FIT Teens) was developed and shown to be promising in improving functioning in adolescents with JFM. In contrast to traditional exercise programs such as aerobic or resistance training, neuromuscular training is a tailored approach which targets gait, posture, balance and movement mechanics which form the foundation for safe exercise participation with reduced risk for injury or pain (and hence more tolerable by JFM patients). The aim of this pilot feasibility study was to establish whether objective biomechanical assessment including sophisticated 3-D motion analysis would be useful in measuring improvements in strength, balance, gait, and functional performance after participation in the 8-week FIT Teens program. Eleven female participants with JFM (ages 12-18 years) completed pre- and post-treatment assessments of biomechanics, including walking gait analysis, lower extremity strength assessment, functional performance, and dynamic postural stability. Descriptive data indicated that mechanics of walking gait and functional performance appeared to improve after treatment. Hip abduction strength and dynamic postural control also demonstrated improvements bilaterally. Overall, the results of this pilot study offer initial evidence for the utility of biomechanical assessment to objectively demonstrate observable changes in biomechanical performance after an integrated training intervention for youth with JFM. If replicated in larger controlled studies, findings would suggest that through the FIT Teens intervention

Fundamental biomechanics of the spine--What we have learned in the past 25 years and future directions.

Science.gov (United States)

Oxland, Thomas R

2016-04-11

Since the publication of the 2nd edition of White and Panjabi׳s textbook, Clinical Biomechanics of the Spine in 1990, there has been considerable research on the biomechanics of the spine. The focus of this manuscript will be to review what we have learned in regards to the fundamentals of spine biomechanics. Topics addressed include the whole spine, the functional spinal unit, and the individual components of the spine (e.g. vertebra, intervertebral disc, spinal ligaments). In these broad categories, our understanding in 1990 is reviewed and the important knowledge or understanding gained through the subsequent 25 years of research is highlighted. Areas where our knowledge is lacking helps to identify promising topics for future research. In this manuscript, as in the White and Panjabi textbook, the emphasis is on experimental research using human material, either in vivo or in vitro. The insights gained from mathematical models and animal experimentation are included where other data are not available. This review is intended to celebrate the substantial gains that have been made in the field over these past 25 years and also to identify future research directions. Copyright © 2015 Elsevier Ltd. All rights reserved.

Vesicle biomechanics in a time-varying magnetic field.

Science.gov (United States)

Ye, Hui; Curcuru, Austen

2015-01-01

Cells exhibit distortion when exposed to a strong electric field, suggesting that the field imposes control over cellular biomechanics. Closed pure lipid bilayer membranes (vesicles) have been widely used for the experimental and theoretical studies of cellular biomechanics under this electrodeformation. An alternative method used to generate an electric field is by electromagnetic induction with a time-varying magnetic field. References reporting the magnetic control of cellular mechanics have recently emerged. However, theoretical analysis of the cellular mechanics under a time-varying magnetic field is inadequate. We developed an analytical theory to investigate the biomechanics of a modeled vesicle under a time-varying magnetic field. Following previous publications and to simplify the calculation, this model treated the inner and suspending media as lossy dielectrics, the membrane thickness set at zero, and the electric resistance of the membrane assumed to be negligible. This work provided the first analytical solutions for the surface charges, electric field, radial pressure, overall translational forces, and rotational torques introduced on a vesicle by the time-varying magnetic field. Frequency responses of these measures were analyzed, particularly the frequency used clinically by transcranial magnetic stimulation (TMS). The induced surface charges interacted with the electric field to produce a biomechanical impact upon the vesicle. The distribution of the induced surface charges depended on the orientation of the coil and field frequency. The densities of these charges were trivial at low frequency ranges, but significant at high frequency ranges. The direction of the radial force on the vesicle was dependent on the conductivity ratio between the vesicle and the medium. At relatively low frequencies (biomechanics under a time-varying magnetic field. Biological effects of clinical TMS are not likely to occur via alteration of the biomechanics of brain

Factors Related to Students' Learning of Biomechanics Concepts

Science.gov (United States)

Hsieh, ChengTu; Smith, Jeremy D.; Bohne, Michael; Knudson, Duane

2012-01-01

The purpose of this study was to replicate and expand a previous study to identify the factors that affect students' learning of biomechanical concepts. Students were recruited from three universities (N = 149) located in the central and western regions of the United States. Data from 142 students completing the Biomechanics Concept Inventory…

Biomechanics of occlusion--implications for oral rehabilitation.

Science.gov (United States)

Peck, C C

2016-03-01

The dental occlusion is an important aspect of clinical dentistry; there are diverse functional demands ranging from highly precise tooth contacts to large crushing forces. Further, there are dogmatic, passionate and often diverging views on the relationship between the dental occlusion and various diseases and disorders including temporomandibular disorders, non-carious cervical lesions and tooth movement. This study provides an overview of the biomechanics of the masticatory system in the context of the dental occlusion's role in function. It explores the adaptation and precision of dental occlusion, its role in bite force, jaw movement, masticatory performance and its influence on the oro-facial musculoskeletal system. Biomechanics helps us better understand the structure and function of biological systems and consequently an understanding of the forces on, and displacements of, the dental occlusion. Biomechanics provides insight into the relationships between the dentition, jaws, temporomandibular joints, and muscles. Direct measurements of tooth contacts and forces are difficult, and biomechanical models have been developed to better understand the relationship between the occlusion and function. Importantly, biomechanical research will provide knowledge to help correct clinical misperceptions and inform better patient care. The masticatory system demonstrates a remarkable ability to adapt to a changing biomechanical environment and changes to the dental occlusion or other components of the musculoskeletal system tend to be well tolerated. © 2015 John Wiley & Sons Ltd.

CURRENT CONCEPTS IN BIOMECHANICAL INTERVENTIONS FOR PATELLOFEMORAL PAIN

Science.gov (United States)

Meira, Erik P.

2016-01-01

Patellofemoral pain (PFP) has historically been a complex and enigmatic issue. Many of the factors thought to relate to PFP remain after patients' symptoms have resolved making their clinical importance difficult to determine. The tissue homeostasis model proposed by Dye in 2005 can assist with understanding and implementing biomechanical interventions for PFP. Under this model, the goal of interventions for PFP should be to re-establish patellofemoral joint (PFJ) homeostasis through a temporary alteration of load to the offended tissue, followed by incrementally restoring the envelope of function to the baseline level or higher. High levels of PFJ loads, particularly in the presence of an altered PFJ environment, are thought to be a factor in the development of PFP. Clinical interventions often aim to alter the biomechanical patterns that are thought to result in elevated PFJ loads while concurrently increasing the load tolerance capabilities of the tissue through therapeutic exercise. Biomechanics may play a role in PFJ load modification not only when addressing proximal and distal components, but also when considering the involvement of more local factors such as the quadriceps musculature. Biomechanical considerations should consider the entire kinetic chain including the hip and the foot/ankle complex, however the beneficial effects of these interventions may not be the result of long-term biomechanical changes. Biomechanical alterations may be achieved through movement retraining, but the interventions likely need to be task-specific to alter movement patterns. The purpose of this commentary is to describe biomechanical interventions for the athlete with PFP to encourage a safe and complete return to sport. Level of Evidence 5 PMID:27904791

Age-related changes in biomechanical properties of transgenic porcine pulmonary and aortic conduits

International Nuclear Information System (INIS)

Wilczek, Piotr; Malota, Zbigniew; Lesiak, Anna; Niemiec-Cyganek, Aleksandra; Kubin, Barbara; Nozynski, Jerzy; Mzyk, Aldona; Gramatyka, Michalina; Slomski, Ryszard; Wilczek, Grazyna; Opiela, Jolanta

2014-01-01

The limitations associated with conventional valve prosthesis have led to a search for alternatives. One potential approach is tissue engineering. Most tissue engineering studies have described the biomechanical properties of heart valves derived from adult pigs. However, because one of the factors affecting the function of valve prosthesis after implantation is appropriate sizing for a given patient, it is important to evaluate the usefulness of a heart valve given the donor animal’s weight and age. The aim of this study was to evaluate how the age of a pig can influence the biomechanical and hemodynamical properties of porcine heart valve prosthesis after acellularization. Acellular porcine aortic and pulmonary valve conduits were used. Hearts were harvested from animals differing in weight and age. The biomechanical properties of the valves were then characterized using a uniaxial tensile test. Moreover, computer simulations based on the finite element method (FEM) were used to study the influence of biomechanical properties on the hemodynamic conditions. Studying biomechanical and morphological changes in porcine heart valve conduits according to the weight and age of the animals can be valuable for developing age-targeted therapy using tissue engineering techniques. (paper)

Applied Biomechanics in an Instructional Setting

Science.gov (United States)

Hudson, Jackie L.

2006-01-01

Biomechanics is the science of how people move better, meaning more skillfully and more safely. This article places more emphasis on skill rather than safety, though there are many parallels between them. It shares a few features of the author's paradigm of applied biomechanics and discusses an integrated approach toward a middle school football…

Biomechanical Loading Modulates Proinflammatory and Bone Resorptive Mediators in Bacterial-Stimulated PDL Cells

Directory of Open Access Journals (Sweden)

Andressa Vilas Boas Nogueira

2014-01-01

Full Text Available The present study aimed to evaluate in vitro whether biomechanical loading modulates proinflammatory and bone remodeling mediators production by periodontal ligament (PDL cells in the presence of bacterial challenge. Cells were seeded on BioFlex culture plates and exposed to Fusobacterium nucleatum ATCC 25586 and/or cyclic tensile strain (CTS of low (CTSL and high (CTSH magnitudes for 1 and 3 days. Synthesis of cyclooxygenase-2 (COX2 and prostaglandin E2 (PGE2 was evaluated by ELISA. Gene expression and protein secretion of osteoprotegerin (OPG and receptor activator of nuclear factor kappa-B ligand (RANKL were evaluated by quantitative RT-PCR and ELISA, respectively. F. nucleatum increased the production of COX2 and PGE2, which was further increased by CTS. F. nucleatum-induced increase of PGE2 synthesis was significantly (P<0.05 increased when CTSH was applied at 1 and 3 days. In addition, CTSH inhibited the F. nucleatum-induced upregulation of OPG at 1 and 3 days, thereby increasing the RANKL/OPG ratio. OPG and RANKL mRNA results correlated with the protein results. In summary, our findings provide original evidence that CTS can enhance bacterial-induced syntheses of molecules associated with inflammation and bone resorption by PDL cells. Therefore, biomechanical, such as orthodontic or occlusal, loading may enhance the bacterial-induced inflammation and destruction in periodontitis.

Biomechanics and tennis.

Science.gov (United States)

Elliott, B

2006-05-01

Success in tennis requires a mix of player talent, good coaching, appropriate equipment, and an understanding of those aspects of sport science pertinent to the game. This paper outlines the role that biomechanics plays in player development from sport science and sport medicine perspectives. Biomechanics is a key area in player development because all strokes have a fundamental mechanical structure and sports injuries primarily have a mechanical cause.

Effects of Inflammation on Multiscale Biomechanical Properties of Cartilaginous Cells and Tissues.

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Nguyen, Q T; Jacobsen, T D; Chahine, N O

2017-11-13

Cells within cartilaginous tissues are mechanosensitive and thus require mechanical loading for regulation of tissue homeostasis and metabolism. Mechanical loading plays critical roles in cell differentiation, proliferation, biosynthesis, and homeostasis. Inflammation is an important event occurring during multiple processes, such as aging, injury, and disease. Inflammation has significant effects on biological processes as well as mechanical function of cells and tissues. These effects are highly dependent on cell/tissue type, timing, and magnitude. In this review, we summarize key findings pertaining to effects of inflammation on multiscale mechanical properties at subcellular, cellular, and tissue level in cartilaginous tissues, including alterations in mechanotransduction and mechanosensitivity. The emphasis is on articular cartilage and the intervertebral disc, which are impacted by inflammatory insults during degenerative conditions such as osteoarthritis, joint pain, and back pain. To recapitulate the pro-inflammatory cascades that occur in vivo, different inflammatory stimuli have been used for in vitro and in situ studies, including tumor necrosis factor (TNF), various interleukins (IL), and lipopolysaccharide (LPS). Therefore, this review will focus on the effects of these stimuli because they are the best studied pro-inflammatory cytokines in cartilaginous tissues. Understanding the current state of the field of inflammation and cell/tissue biomechanics may potentially identify future directions for novel and translational therapeutics with multiscale biomechanical considerations.

Trends in the development of microfluidic cell biochips for in vitro hepatotoxicity.

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Baudoin, Régis; Corlu, Anne; Griscom, Laurent; Legallais, Cécile; Leclerc, Eric

2007-06-01

Current developments in the technological fields of liver tissue engineering, bioengineering, biomechanics, microfabrication and microfluidics have lead to highly complex and pertinent new tools called "cell biochips" for in vitro toxicology. The purpose of "cell biochips" is to mimic organ tissues in vitro in order to partially reduce the amount of in vivo testing. These "cell biochips" consist of microchambers containing engineered tissue and living cell cultures interconnected by a microfluidic network, which allows the control of microfluidic flows for dynamic cultures, by continuous feeding of nutrients to cultured cells and waste removal. Cell biochips also allow the control of physiological contact times of diluted molecules with the tissues and cells, for rapid testing of sample preparations or specific addressing. Cell biochips can be situated between in vitro and in vivo testing. These types of systems can enhance functionality of cells by mimicking the tissue architecture complexities when compared to in vitro analysis but at the same time present a more rapid and simple process when compared to in vivo testing procedures. In this paper, we first introduce the concepts of microfluidic and biochip systems based on recent progress in microfabrication techniques used to mimic liver tissue in vitro. This includes progress and understanding in biomaterials science (cell culture substrate), biomechanics (dynamic cultures conditions) and biology (tissue engineering). The development of new "cell biochips" for chronic toxicology analysis of engineered tissues can be achieved through the combination of these research domains. Combining these advanced research domains, we then present "cell biochips" that allow liver chronic toxicity analysis in vitro on engineered tissues. An extension of the "cell biochip" idea has also allowed "organ interactions on chip", which can be considered as a first step towards the replacement of animal testing using a combined liver

Biomechanical aspects of bone microstructure in vertebrates ...

Indian Academy of Sciences (India)

Prakash

2009-10-29

Oct 29, 2009 ... Biomechanical or biophysical principles can be applied to study biological structures in their modern or .... Accounting for the flow in a horizontal pipe, z1 = z2, and ..... OH, USA for providing financial assistance and academic.

Problems of Sport Biomechanics and Robotics

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Wlodzimierz S. Erdmann

2013-02-01

Full Text Available This paper presents many common areas of interest of different specialists. There are problems described from sport, biomechanics, sport biomechanics, sport engineering, robotics, biomechanics and robotics, sport biomechanics and robotics. There are many approaches to sport from different sciences and engineering. Robotics is a relatively new area and has had moderate attention from sport specialists. The aim of this paper is to present several areas necessary to develop sport robots based on biomechanics and also to present different types of sport robots: serving balls, helping to provide sports training, substituting humans during training, physically participating in competitions, physically participating in competitions against humans, serving as models of real sport performance, helping organizers of sport events and robot toys. Examples of the application of robots in sports communities are also given.

Biomechanical regulation of in vitro cardiogenesis for tissue-engineered heart repair.

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Zimmermann, Wolfram-Hubertus

2013-01-01

The heart is a continuously pumping organ with an average lifespan of eight decades. It develops from the onset of embryonic cardiogenesis under biomechanical load, performs optimally within a defined range of hemodynamic load, and fails if acutely or chronically overloaded. Unloading of the heart leads to defective cardiogenesis in utero, but can also lead to a desired therapeutic outcome (for example, in patients with heart failure under left ventricular assist device therapy). In light of the well-documented relevance of mechanical loading for cardiac physiology and pathology, it is plausible that tissue engineers have integrated mechanical stimulation regimens into protocols for heart muscle construction. To achieve optimal results, physiological principles of beat-to-beat myocardial loading and unloading should be simulated. In addition, heart muscle engineering, in particular if based on pluripotent stem cell-derived cardiomyocytes, may benefit from staggered tonic loading protocols to simulate viscoelastic properties of the prenatal and postnatal myocardial stroma. This review will provide an overview of heart muscle mechanics, summarize observations on the role of mechanical loading for heart development and postnatal performance, and discuss how physiological loading regimens can be exploited to advance myocardial tissue engineering towards a therapeutic application.

Visualisation to enhance biomechanical tuning of ankle-foot orthoses (AFOs in stroke: study protocol for a randomised controlled trial

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Carse Bruce

2011-12-01

Full Text Available Abstract Background There are a number of gaps in the evidence base for the use of ankle-foot orthoses for stroke patients. Three dimensional motion analysis offers an ideal method for objectively obtaining biomechanical gait data from stroke patients, however there are a number of major barriers to its use in routine clinical practice. One significant problem is the way in which the biomechanical data generated by these systems is presented. Through the careful design of bespoke biomechanical visualisation software it may be possible to present such data in novel ways to improve clinical decision making, track progress and increase patient understanding in the context of ankle-foot orthosis tuning. Methods A single-blind randomised controlled trial will be used to compare the use of biomechanical visualisation software in ankle-foot orthosis tuning against standard care (tuning using observation alone. Participants (n = 70 will have experienced a recent hemiplegia (1-12 months and will be identified by their care team as being suitable candidates for a rigid ankle-foot orthosis. The primary outcome measure will be walking velocity. Secondary outcome measures include; lower limb joint kinematics (thigh and shank global orientations & kinetics (knee and hip flexion/extension moments, ground reaction force FZ2 peak magnitude, step length, symmetry ratio based on step length, Modified Ashworth Scale, Modified Rivermead Mobility Index and EuroQol (EQ-5D. Additional qualitative measures will also be taken from participants (patients and clinicians at the beginning and end of their participation in the study. The main aim of the study is to determine whether or not the visualisation of biomechanical data can be used to improve the outcomes of tuning ankle-foot orthoses for stroke patients. Discussion In addition to answering the primary research question the broad range of measures that will be taken during this study are likely to contribute to a

Analysis of Big Data in Gait Biomechanics: Current Trends and Future Directions.

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Phinyomark, Angkoon; Petri, Giovanni; Ibáñez-Marcelo, Esther; Osis, Sean T; Ferber, Reed

2018-01-01

The increasing amount of data in biomechanics research has greatly increased the importance of developing advanced multivariate analysis and machine learning techniques, which are better able to handle "big data". Consequently, advances in data science methods will expand the knowledge for testing new hypotheses about biomechanical risk factors associated with walking and running gait-related musculoskeletal injury. This paper begins with a brief introduction to an automated three-dimensional (3D) biomechanical gait data collection system: 3D GAIT, followed by how the studies in the field of gait biomechanics fit the quantities in the 5 V's definition of big data: volume, velocity, variety, veracity, and value. Next, we provide a review of recent research and development in multivariate and machine learning methods-based gait analysis that can be applied to big data analytics. These modern biomechanical gait analysis methods include several main modules such as initial input features, dimensionality reduction (feature selection and extraction), and learning algorithms (classification and clustering). Finally, a promising big data exploration tool called "topological data analysis" and directions for future research are outlined and discussed.

A scalable platform for biomechanical studies of tissue cutting forces

International Nuclear Information System (INIS)

Valdastri, P; Tognarelli, S; Menciassi, A; Dario, P

2009-01-01

This paper presents a novel and scalable experimental platform for biomechanical analysis of tissue cutting that exploits a triaxial force-sensitive scalpel and a high resolution vision system. Real-time measurements of cutting forces can be used simultaneously with accurate visual information in order to extract important biomechanical clues in real time that would aid the surgeon during minimally invasive intervention in preserving healthy tissues. Furthermore, the in vivo data gathered can be used for modeling the viscoelastic behavior of soft tissues, which is an important issue in surgical simulator development. Thanks to a modular approach, this platform can be scaled down, thus enabling in vivo real-time robotic applications. Several cutting experiments were conducted with soft porcine tissues (lung, liver and kidney) chosen as ideal candidates for biopsy procedures. The cutting force curves show repeated self-similar units of localized loading followed by unloading. With regards to tissue properties, the depth of cut plays a significant role in the magnitude of the cutting force acting on the blade. Image processing techniques and dedicated algorithms were used to outline the surface of the tissues and estimate the time variation of the depth of cut. The depth of cut was finally used to obtain the normalized cutting force, thus allowing comparative biomechanical analysis

Comparing handrim biomechanics for treadmill and overground wheelchair propulsion

Science.gov (United States)

Kwarciak, Andrew M.; Turner, Jeffrey T.; Guo, Liyun; Richter, W. Mark

2010-01-01

Study design Cross-sectional study. Objectives To compare handrim biomechanics recorded during overground propulsion to those recorded during propulsion on a motor-driven treadmill. Setting Biomechanics laboratory. Methods Twenty-eight manual wheelchair users propelled their own wheelchairs, at a self-selected speed, on a low-pile carpet and on a wheelchair accessible treadmill. Handrim biomechanics were recorded with an OptiPush instrumented wheelchair wheel. Results Across the two conditions, all handrim biomechanics were found to be similar and highly correlated (r > 0.85). Contact angle, peak force, average force, and peak axle moment differed by 1.6% or less across the two conditions. While not significant, power output and cadence tended to be slightly higher for the treadmill condition (3.5% and 3.6%, respectively), due to limitations in adjusting the treadmill grade. Conclusion Based on the results of this study, a motor-driven treadmill can serve as a valid surrogate for overground studies of wheelchair propulsion. PMID:21042332

Effects of sex and obesity on gait biomechanics before and six months after total knee arthroplasty: A longitudinal cohort study.

Science.gov (United States)

Paterson, K L; Sosdian, L; Hinman, R S; Wrigley, T V; Kasza, J; Dowsey, M; Choong, P; Bennell, K L

2018-03-01

Gait biomechanics, sex, and obesity can contribute to suboptimal outcomes from primary total knee arthroplasty. The aims of this study were to i) determine if sex and/or obesity influence the amount of change in gait biomechanics from pre-surgery to six months post-surgery and; ii) assess if gait returns to normal in men and women. Three-dimensional gait analysis was performed on 43 patients undergoing primary total knee arthroplasty for knee osteoarthritis (pre- and six months post-operative) and 40 asymptomatic controls. Mixed linear regression models were fit to assess which factors influenced change in gait biomechanics within the arthroplasty cohort, and interaction terms were included to assess if biomechanics returned to normal following surgery. Male peak knee adduction moment (p biomechanics after arthroplasty. Men retained abnormal gait patterns after surgery, whilst women did not. Further research should determine the long-term implications of gait abnormalities seen in men after arthroplasty. Copyright © 2018 Elsevier B.V. All rights reserved.

Dr Dapertutto's biomechanics

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Stojmenović Dragan

2015-01-01

Full Text Available The subject matter of the research is the basic models of Meyerhold's biomechanics, which were used to define its theoretical principles. Professor Meyerhold, the theatrical leader of an eccentric stream, with which he changed the modern understanding of the theatre, established the technique of biomechanics by analysing the calculated type of movement. The analysis determines the answers to the questions: What kind of influence does Taylor's 'scientific management of work' have on defining the principles of Meyerhold's techniques of biomechanics? Which aesthetic models of stage movement were some of the basic subjects of Meyerhold's research? Meyerhold's theatrical work has been researched by a number of theatre theorists. However, how much does his work influence the film medium?.

Biomechanics and mechanobiology in functional tissue engineering

NARCIS (Netherlands)

Guilak, F.; Butler, D.L.; Goldstein, S.A.; Baaijens, F.P.T.

2014-01-01

The field of tissue engineering continues to expand and mature, and several products are now in clinical use, with numerous other preclinical and clinical studies underway. However, specific challenges still remain in the repair or regeneration of tissues that serve a predominantly biomechanical

[Evaluation of corneal biomechanics in keratoconus using dynamic ultra-high-speed Scheimpflug measurements].

Science.gov (United States)

Brettl, S; Franko Zeitz, P; Fuchsluger, T A

2018-06-22

The in vivo analysis of corneal biomechanics in patients with keratoconus is especially of interest with respect to diagnosis, follow-up and monitoring of the disease. For a better understanding it is necessary to describe the potential of dynamic Scheimpflug measurements for the detection and interpretation of biomechanical changes in keratoconus. The current state of analyzing biomechanical changes in keratoconus with the Corvis ST (Oculus Optikgeräte GmbH, Wetzlar, Germany) is described. This technique represents a new approach for understanding corneal biomechanics. Furthermore, it was investigated whether the device can biomechanically quantify a rigidity increasing effect of therapeutic UV-crosslinking and whether early stages of keratoconus can be detected using dynamic Scheimpflug analysis. In patients with keratoconus, the in vivo analysis of corneal biomechanics using dynamic Scheimpflug measurements as a supplementary procedure can be of advantage with respect to disease management. By optimization of screening of subclinical keratoconus stages, this method widens the analytic spectrum regarding diagnosis and follow-up of the disease; however, further studies are required to evaluate whether visual outcome of affected patients can be improved by earlier diagnosis.

Biomechanical aspects of bone microstructure in vertebrates

Indian Academy of Sciences (India)

2009-10-29

Oct 29, 2009 ... Biomechanical or biophysical principles can be applied to study biological structures in their modern or fossil form. Bone is an important tissue in paleontological studies as it is a commonly preserved element in most fossil vertebrates, and can often allow its microstructures such as lacuna and canaliculi to ...

Biomechanics of Thoracolumbar Burst and Chance-Type Fractures during Fall from Height

Science.gov (United States)

Ivancic, Paul C.

2014-01-01

Study Design In vitro biomechanical study. Objective To investigate the biomechanics of thoracolumbar burst and Chance-type fractures during fall from height. Methods Our model consisted of a three-vertebra human thoracolumbar specimen (n = 4) stabilized with muscle force replication and mounted within an impact dummy. Each specimen was subjected to a single fall from an average height of 2.1 m with average velocity at impact of 6.4 m/s. Biomechanical responses were determined using impact load data combined with high-speed movie analyses. Injuries to the middle vertebra of each spinal segment were evaluated using imaging and dissection. Results Average peak compressive forces occurred within 10 milliseconds of impact and reached 40.3 kN at the ground, 7.1 kN at the lower vertebra, and 3.6 kN at the upper vertebra. Subsequently, average peak flexion (55.0 degrees) and tensile forces (0.7 kN upper vertebra, 0.3 kN lower vertebra) occurred between 43.0 and 60.0 milliseconds. The middle vertebra of all specimens sustained pedicle and endplate fractures with comminution, bursting, and reduced height of its vertebral body. Chance-type fractures were observed consisting of a horizontal split fracture through the laminae and pedicles extending anteriorly through the vertebral body. Conclusions We hypothesize that the compression fractures of the pedicles and vertebral body together with burst fracture occurred at the time of peak spinal compression, 10 milliseconds. Subsequently, the onset of Chance-type fracture occurred at 20 milliseconds through the already fractured and weakened pedicles and vertebral body due to flexion-distraction and a forward shifting spinal axis of rotation. PMID:25083357

Neck muscle biomechanics and neural control.

Science.gov (United States)

Fice, Jason Bradley; Siegmund, Gunter P; Blouin, Jean-Sebastien

2018-04-18

The mechanics, morphometry, and geometry of our joints, segments and muscles are fundamental biomechanical properties intrinsic to human neural control. The goal of our study was to investigate if the biomechanical actions of individual neck muscles predicts their neural control. Specifically, we compared the moment direction & variability produced by electrical stimulation of a neck muscle (biomechanics) to their preferred activation direction & variability (neural control). Subjects sat upright with their head fixed to a 6-axis load cell and their torso restrained. Indwelling wire electrodes were placed into the sternocleidomastoid (SCM), splenius capitis (SPL), and semispinalis capitis (SSC) muscles. The electrically stimulated direction was defined as the moment direction produced when a current (2-19mA) was passed through each muscle's electrodes. Preferred activation direction was defined as the vector sum of the spatial tuning curve built from RMS EMG when subjects produced isometric moments at 7.5% and 15% of their maximum voluntary contraction (MVC) in 26 3D directions. The spatial tuning curves at 15% MVC were well-defined (unimodal, pbiomechanics but, as activation increases, biomechanical constraints in part dictate the activation of synergistic neck muscles.

Evaluation of standardized porcine bone models to test primary stability of dental implants, using biomechanical tests and Micro-CT. An in vitro pilot study

Directory of Open Access Journals (Sweden)

C. Delmondes Freitas Dantas

2015-06-01

Full Text Available Aim This study evaluated a new porcine bone model to test the primary stability of different implants, analyzing Micro-CT, insertion torque, and pull-out strength. Materials and methods Bone cylinders were prepared from porcine bone and separated into 2 groups: 10 high density bone cylinders (HDB, and 10 low density bone cylinders (LDB. Then, 3D pre-implant analyses were performed, evaluating tridimensional bone density (ratio of trabecular bone volume and total tomographic volume, BV/TV, trabecular separation; percentage of closed pores; percentage of open pores; percentage of total porosity, in 3 bone levels (L1 bone volume corresponding to the internal part of the threads; L2 corresponding to the area between 0 to 0.5 mm from the end of threads; L3 corresponding to the area between 0.5 to 1.5 mm from the end of threads. Twenty implants of two different macrostructures were inserted in the bone cylinders, and divided into 4 groups (5 implants each: Group 1, e-Fix HE implant placed in HDB cylinder; Group 2, e-Fix HE implant in LDB cylinder; Group 3, e-Fix HE Silver implant placed in HDB cylinder; Group 4, e-Fix HE Silver implant in LDB cylinder. The insertion torque was recorded and bone cylinders were re-evaluated by Micro-CT (post-implant analysis. Then a pull-out strength test was performed. Results 3D analysis showed that pre- and post-implants intra-groups evaluation had statistically significant differences in Group 3 and 4, for all tomographic parameters assessed. Group 3 showed the best values for biomechanical tests (Friedman Test, p<0.05. Conclusion This methodology can produce standardized bone cylinders of high and low bone density, in which different implant designs are able to promote different effects, evidenced by biomechanical and image analysis.

Biomechanics Strategies for Space Closure in Deep Overbite

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Harryanto Wijaya

2013-07-01

Full Text Available Space closure is an interesting aspect of orthodontic treatment related to principles of biomechanics. It should be tailored individually based on patient’s diagnosis and treatment plan. Understanding the space closure biomechanics basis leads to achieve the desired treatment objective. Overbite deepening and losing posterior anchorage are the two most common unwanted side effects in space closure. Conventionally, correction of overbite must be done before space closure resulted in longer treatment. Application of proper space closure biomechanics strategies is necessary to achieve the desired treatment outcome. This cases report aimed to show the space closure biomechanics strategies that effectively control the overbite as well as posterior anchorage in deep overbite patients without increasing treatment time. Two patients who presented with class II division 1 malocclusion were treated with fixed orthodontic appliance. The primary strategies included extraction space closure on segmented arch that employed two-step space closure, namely single canine retraction simultaneously with incisors intrusion followed by enmasse retraction of four incisors by using differential moment concept. These strategies successfully closed the space, corrected deep overbite and controlled posterior anchorage simultaneously so that the treatment time was shortened. Biomechanics strategies that utilized were effective to achieve the desired treatment outcome.

Computational modeling in biomechanics

CERN Document Server

Mofrad, Mohammad

2010-01-01

This book provides a glimpse of the diverse and important roles that modern computational technology is playing in various areas of biomechanics. It includes unique chapters on ab initio quantum mechanical, molecular dynamic and scale coupling methods..

Citation metrics of excellence in sports biomechanics research.

Science.gov (United States)

Knudson, Duane

2017-11-13

This study extended research on key citation metrics of winners of two career scholar awards in sports biomechanics. Google Scholar (GS) was searched using Harzing's Publish or Perish software for the 13 most recent winners of the ISBS Geoffrey Dyson Award and the ASB Jim Hay Memorial Award. Returned records were corrected for author, and publications excluded for all but peer-reviewed journal articles, proceedings articles, chapters and books in English. These recent award winners had published about 150 publications that had been cited typically 4,082 and 6,648 times over a 26- and 28-year period before receiving these career awards for sports biomechanics research. Estimated median citations at time of their awards were 2,927 and 4,907 for the Dyson and Hay awards, respectively. Award winners had mean Hirsh indexes of 32-45 and mean h i of 19-28. Their mean g indexes (59-84) and their numerous citation classics (C > 100) indicated that they had many influential publications. The citation metrics of these scholars were outstanding and consistent with recent studies of top scholars in biomechanics and kinesiology/exercise science. Careful searching, cleaning and interpretation of several scholar-level citation metrics may provide useful confirmatory evidence for evaluations of awards committees.

Shoe heel abrasion and its possible biomechanical cause: a transversal study with infantry recruits.

Science.gov (United States)

Baumfeld, Daniel; Raduan, Fernando C; Macedo, Benjamim; Silva, Thiago Alexandre Alves; Baumfeld, Tiago; Favato, Danilo Fabrino; de Andrade, Marco Antonio Percope; Nery, Caio

2015-11-19

Excessive shoe heel abrasion is of concern to patients and shoe manufacturers, but little scientific information is available about this feature and its possible causes. The purpose of this study was to relate this phenomenon with biomechanical factors that could predispose to shoe heel abrasion. Ninety-seven recruits (median age 25) were enrolled in this study. Shoe abrasion was assessed manually with a metric plastic tape on the posterior part of the heel that comes in contact with the ground. The number of sprains, foot alignment, and calf muscle shortening (Silfverskiold test) was also assessed in order to relate it with shoe heel abrasion. After using our exclusion criteria, 86 recruits and 172 were considered for this study. The most common abrasion site was the lateral portion of the heel surface (50 %). Forty-four percent of the participants had neutral hind-foot alignment and 39 % had valgus alignment. Twenty-six (30 %) patients have had previous ankle or foot sprains. Neutral foot was related with less calf muscle shortening. On the other hand, valgus hind-foot alignment was more associated with Achilles shortening (p study was able to correlate shoe heel abrasion with biomechanical causes (neutral alignment-uniform abrasion/varus alignment-central and lateral abrasion). More effort has to be done to continue evaluating outsole abrasion with its possible biomechanical cause in order to predict and treat possible associated injuries.

Biomechanics, Exercise Physiology, and the 75th Anniversary of RQES

Science.gov (United States)

Hamill, Joseph; Haymes, Emily M.

2005-01-01

The purpose of this paper is to review the biomechanics and exercise physiology studies published in the Research Quarterly for Exercise and Sport (RQES) over the past 75 years. Studies in biomechanics, a relatively new subdiscipline that evolved from kinesiology, first appeared in the journal about 40 years ago. Exercise physiology studies have…

Artificial intelligence in sports biomechanics: new dawn or false hope?

Science.gov (United States)

Bartlett, Roger

2006-12-15

This article reviews developments in the use of Artificial Intelligence (AI) in sports biomechanics over the last decade. It outlines possible uses of Expert Systems as diagnostic tools for evaluating faults in sports movements ('techniques') and presents some example knowledge rules for such an expert system. It then compares the analysis of sports techniques, in which Expert Systems have found little place to date, with gait analysis, in which they are routinely used. Consideration is then given to the use of Artificial Neural Networks (ANNs) in sports biomechanics, focusing on Kohonen self-organizing maps, which have been the most widely used in technique analysis, and multi-layer networks, which have been far more widely used in biomechanics in general. Examples of the use of ANNs in sports biomechanics are presented for javelin and discus throwing, shot putting and football kicking. I also present an example of the use of Evolutionary Computation in movement optimization in the soccer throw in, which predicted an optimal technique close to that in the coaching literature. After briefly overviewing the use of AI in both sports science and biomechanics in general, the article concludes with some speculations about future uses of AI in sports biomechanics. Key PointsExpert Systems remain almost unused in sports biomechanics, unlike in the similar discipline of gait analysis.Artificial Neural Networks, particularly Kohonen Maps, have been used, although their full value remains unclear.Other AI applications, including Evolutionary Computation, have received little attention.

Mathematical foundations of biomechanics.

Science.gov (United States)

Niederer, Peter F

2010-01-01

The aim of biomechanics is the analysis of the structure and function of humans, animals, and plants by means of the methods of mechanics. Its foundations are in particular embedded in mathematics, physics, and informatics. Due to the inherent multidisciplinary character deriving from its aim, biomechanics has numerous connections and overlapping areas with biology, biochemistry, physiology, and pathophysiology, along with clinical medicine, so its range is enormously wide. This treatise is mainly meant to serve as an introduction and overview for readers and students who intend to acquire a basic understanding of the mathematical principles and mechanics that constitute the foundation of biomechanics; accordingly, its contents are limited to basic theoretical principles of general validity and long-range significance. Selected examples are included that are representative for the problems treated in biomechanics. Although ultimate mathematical generality is not in the foreground, an attempt is made to derive the theory from basic principles. A concise and systematic formulation is thereby intended with the aim that the reader is provided with a working knowledge. It is assumed that he or she is familiar with the principles of calculus, vector analysis, and linear algebra.

Biomechanics research in ski jumping, 1991-2006.

Science.gov (United States)

Schwameder, Hermann

2008-01-01

In this paper, I review biomechanics research in ski jumping with a specific focus on publications presented between 1991 and 2006 on performance enhancement, limiting factors of the take-off, specific training and conditioning, aerodynamics, and safety. The first section presents a brief description of ski jumping phases (in-run, take-off, early flight, stable flight, and landing) regarding the biomechanical and functional fundamentals. The most important and frequently used biomechanical methods in ski jumping (kinematics, ground reaction force analyses, muscle activation patterns, aerodynamics) are summarized in the second section. The third section focuses on ski jumping articles and research findings published after the establishment of the V-technique in 1991, as the introduction of this technique has had a major influence on performance enhancement, ski jumping regulations, and the construction of hill profiles. The final section proposes topics for future research in the biomechanics of ski jumping, including: take-off and early flight and the relative roles of vertical velocity and forward somersaulting angular momentum; optimal jumping patterns utilizing the capabilities of individual athletes; development of kinematic and kinetic feedback systems for hill jumps; comparisons of simulated and hill jumps; effect of equipment modifications on performance and safety enhancement.

Systems biomechanics of the cell

CERN Document Server

Maly, Ivan V

2013-01-01

Systems Biomechanics of the Cell attempts to outline systems biomechanics of the cell as an emergent and promising discipline. The new field owes conceptually to cell mechanics, organism-level systems biomechanics, and biology of biochemical systems. Its distinct methodology is to elucidate the structure and behavior of the cell by analyzing the unintuitive collective effects of elementary physical forces that interact within the heritable cellular framework. The problematics amenable to this approach includes the variety of cellular activities that involve the form and movement of the cell body and boundary (nucleus, centrosome, microtubules, cortex, and membrane). Among the elementary system effects in the biomechanics of the cell, instability of symmetry, emergent irreversibility, and multiperiodic dissipative motion can be noted. Research results from recent journal articles are placed in this unifying framework. It is suggested that the emergent discipline has the potential to expand the spectrum of ques...

Unified Approach to the Biomechanics of Dental Implantology

Science.gov (United States)

Grenoble, D. E.; Knoell, A. C.

1973-01-01

The human need for safe and effective dental implants is well-recognized. Although many implant designs have been tested and are in use today, a large number have resulted in clinical failure. These failures appear to be due to biomechanical effects, as well as biocompatibility and surgical factors. A unified approach is proposed using multidisciplinary systems technology, for the study of the biomechanical interactions between dental implants and host tissues. The approach progresses from biomechanical modeling and analysis, supported by experimental investigations, through implant design development, clinical verification, and education of the dental practitioner. The result of the biomechanical modeling, analysis, and experimental phases would be the development of scientific design criteria for implants. Implant designs meeting these criteria would be generated, fabricated, and tested in animals. After design acceptance, these implants would be tested in humans, using efficient and safe surgical and restorative procedures. Finally, educational media and instructional courses would be developed for training dental practitioners in the use of the resulting implants.

ARTIFICIAL INTELLIGENCE IN SPORTS BIOMECHANICS: NEW DAWN OR FALSE HOPE?

Directory of Open Access Journals (Sweden)

Roger Bartlett

2006-12-01

Full Text Available This article reviews developments in the use of Artificial Intelligence (AI in sports biomechanics over the last decade. It outlines possible uses of Expert Systems as diagnostic tools for evaluating faults in sports movements ('techniques' and presents some example knowledge rules for such an expert system. It then compares the analysis of sports techniques, in which Expert Systems have found little place to date, with gait analysis, in which they are routinely used. Consideration is then given to the use of Artificial Neural Networks (ANNs in sports biomechanics, focusing on Kohonen self-organizing maps, which have been the most widely used in technique analysis, and multi-layer networks, which have been far more widely used in biomechanics in general. Examples of the use of ANNs in sports biomechanics are presented for javelin and discus throwing, shot putting and football kicking. I also present an example of the use of Evolutionary Computation in movement optimization in the soccer throw in, which predicted an optimal technique close to that in the coaching literature. After briefly overviewing the use of AI in both sports science and biomechanics in general, the article concludes with some speculations about future uses of AI in sports biomechanics.

Biomechanical Strength of Retrograde Fixation in Proximal Third Scaphoid Fractures.

Science.gov (United States)

Daly, Charles A; Boden, Allison L; Hutton, William C; Gottschalk, Michael B

2018-04-01

Current techniques for fixation of proximal pole scaphoid fractures utilize antegrade fixation via a dorsal approach endangering the delicate vascular supply of the dorsal scaphoid. Volar and dorsal approaches demonstrate equivalent clinical outcomes in scaphoid wrist fractures, but no study has evaluated the biomechanical strength for fractures of the proximal pole. This study compares biomechanical strength of antegrade and retrograde fixation for fractures of the proximal pole of the scaphoid. A simulated proximal pole scaphoid fracture was produced in 22 matched cadaveric scaphoids, which were then assigned randomly to either antegrade or retrograde fixation with a cannulated headless compression screw. Cyclic loading and load to failure testing were performed and screw length, number of cycles, and maximum load sustained were recorded. There were no significant differences in average screw length (25.5 mm vs 25.6 mm, P = .934), average number of cyclic loading cycles (3738 vs 3847, P = .552), average load to failure (348 N vs 371 N, P = .357), and number of catastrophic failures observed between the antegrade and retrograde fixation groups (3 in each). Practical equivalence between the 2 groups was calculated and the 2 groups were demonstrated to be practically equivalent (upper threshold P = .010). For this model of proximal pole scaphoid wrist fractures, antegrade and retrograde screw configuration have been proven to be equivalent in terms of biomechanical strength. With further clinical study, we hope surgeons will be able to make their decision for fixation technique based on approaches to bone grafting, concern for tenuous blood supply, and surgeon preference without fear of poor biomechanical properties.

Recent software developments for biomechanical assessment

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Greaves, John O. B.

1990-08-01

While much of the software developed in research laboratories is narrow in focus and suited for a specific experiment, some of it is broad enough and of high enough quality to be useful to others in solving similar problems. Several biomechanical assessment packages are now beginning to emerge, including: * 3D research biomechanics (5- and 6-DOF) with kinematics, kinetics, 32-channel analog data subsystem, and project management. * 3D full-body gait analysis with kinematics, kinetics, EMG charts, and force plate charts. * 2D dynamic rear-foot assessment. * 2D occupational biomechanics lifting task and personnel assessments. * 2D dynamic gait analysis. * Multiple 2D dynamic spine assessments. * 2D sport and biomechanics assessments with kinematics and kinetics. * 2D and 3D equine gait assessments.

Esophageal morphometric and biomechanical changes during aging in rats

DEFF Research Database (Denmark)

Zhao, Jingbo; Gregersen, Hans

of the present study is to investigate the esophageal geometry and biomechanical changes during aging in rats. Materials and methods Twenty-four male Wistar rats, aged from 6 to 22 months, were used in the study. The body weight and the wet weight per length of esophageal segment were measured at the termination...... was found among 12, 18 and 22 months groups (p>0.05). The longitudinal stress-strain curves shifted from right to the left during aging (pstiffness has no obvious...... change after 12 months in the circumferential direction. Furthermore, we confirm that the esophagus was stiffer in the longitudinal direction than in the circumferential direction. Conclusions A pronounced morphometric and biomechanical remodeling was occurred in the rat esophagus during aging...

Modelling biomechanics of bark patterning in grasstrees.

Science.gov (United States)

Dale, Holly; Runions, Adam; Hobill, David; Prusinkiewicz, Przemyslaw

2014-09-01

Bark patterns are a visually important characteristic of trees, typically attributed to fractures occurring during secondary growth of the trunk and branches. An understanding of bark pattern formation has been hampered by insufficient information regarding the biomechanical properties of bark and the corresponding difficulties in faithfully modelling bark fractures using continuum mechanics. This study focuses on the genus Xanthorrhoea (grasstrees), which have an unusual bark-like structure composed of distinct leaf bases connected by sticky resin. Due to its discrete character, this structure is well suited for computational studies. A dynamic computational model of grasstree development was created. The model captures both the phyllotactic pattern of leaf bases during primary growth and the changes in the trunk's width during secondary growth. A biomechanical representation based on a system of masses connected by springs is used for the surface of the trunk, permitting the emergence of fractures during secondary growth to be simulated. The resulting fracture patterns were analysed statistically and compared with images of real trees. The model reproduces key features of grasstree bark patterns, including their variability, spanning elongated and reticulate forms. The patterns produced by the model have the same statistical character as those seen in real trees. The model was able to support the general hypothesis that the patterns observed in the grasstree bark-like layer may be explained in terms of mechanical fractures driven by secondary growth. Although the generality of the results is limited by the unusual structure of grasstree bark, it supports the hypothesis that bark pattern formation is primarily a biomechanical phenomenon.

Computational Biomechanics Theoretical Background and BiologicalBiomedical Problems

CERN Document Server

Tanaka, Masao; Nakamura, Masanori

2012-01-01

Rapid developments have taken place in biological/biomedical measurement and imaging technologies as well as in computer analysis and information technologies. The increase in data obtained with such technologies invites the reader into a virtual world that represents realistic biological tissue or organ structures in digital form and allows for simulation and what is called “in silico medicine.” This volume is the third in a textbook series and covers both the basics of continuum mechanics of biosolids and biofluids and the theoretical core of computational methods for continuum mechanics analyses. Several biomechanics problems are provided for better understanding of computational modeling and analysis. Topics include the mechanics of solid and fluid bodies, fundamental characteristics of biosolids and biofluids, computational methods in biomechanics analysis/simulation, practical problems in orthopedic biomechanics, dental biomechanics, ophthalmic biomechanics, cardiovascular biomechanics, hemodynamics...

Biomechanics of Wheat/Barley Straw and Corn Stover

Energy Technology Data Exchange (ETDEWEB)

Christopher T. Wright; Peter A. Pryfogle; Nathan A. Stevens; Eric D. Steffler; J. Richard Hess; Thomas H. Ulrich

2005-03-01

The lack of understanding of the mechanical characteristics of cellulosic feedstocks is a limiting factor in economically collecting and processing crop residues, primarily wheat and barley stems and corn stover. Several testing methods, including compression, tension, and bend have been investigated to increase our understanding of the biomechanical behavior of cellulosic feedstocks. Biomechanical data from these tests can provide required input to numerical models and help advance harvesting, handling, and processing techniques. In addition, integrating the models with the complete data set from this study can identify potential tools for manipulating the biomechanical properties of plant varieties in such a manner as to optimize their physical characteristics to produce higher value biomass and more energy efficient harvesting practices.

4th International Plant Biomechanics Conference Proceedings (Abstracts)

Energy Technology Data Exchange (ETDEWEB)

Frank W. Telewski; Lothar H. Koehler; Frank W. Ewers

2003-07-20

The 4th International Plant Biomechanics Conference facilitated an interdisciplinary exchange between scientists, engineers, and educators addressing the major questions encountered in the field of Plant Biomechanics. Subjects covered by the conference include: Evolution; Ecology; Mechanoreception; Cell Walls; Genetic Modification; Applied Biomechanics of Whole Plants, Plant Products, Fibers & Composites; Fluid Dynamics; Wood & Trees; Fracture Mechanics; Xylem Pressure & Water Transport; Modeling; and Introducing Plant Biomechanics in Secondary School Education.

Assessment and characterization of in situ rotator cuff biomechanics

Science.gov (United States)

Trent, Erika A.; Bailey, Lane; Mefleh, Fuad N.; Raikar, Vipul P.; Shanley, Ellen; Thigpen, Charles A.; Dean, Delphine; Kwartowitz, David M.

2013-03-01

Rotator cuff disease is a degenerative disorder that is a common, costly, and often debilitating, ranging in severity from partial thickness tear, which may cause pain, to total rupture, leading to loss in function. Currently, clinical diagnosis and determination of disease extent relies primarily on subjective assessment of pain, range of motion, and possibly X-ray or ultrasound images. The final treatment plan however is at the discretion of the clinician, who often bases their decision on personal experiences, and not quantitative standards. The use of ultrasound for the assessment of tissue biomechanics is established, such as in ultrasound elastography, where soft tissue biomechanics are measured. Few studies have investigated the use of ultrasound elastography in the characterization of musculoskeletal biomechanics. To assess tissue biomechanics we have developed a device, which measures the force applied to the underlying musculotendentious tissue while simultaneously obtaining the related ultrasound images. In this work, the musculotendinous region of the infraspinatus of twenty asymptomatic male organized baseball players was examined to access the variability in tissue properties within a single patient and across a normal population. Elastic moduli at percent strains less than 15 were significantly different than those above 15 percent strain within the normal population. No significant difference in tissue properties was demonstrated within a single patient. This analysis demonstrated elastic moduli are variable across individuals and incidence. Therefore threshold elastic moduli will likely be a function of variation in local-tissue moduli as opposed to a specific global value.

Interpreting locomotor biomechanics from the morphology of human footprints.

Science.gov (United States)

Hatala, Kevin G; Wunderlich, Roshna E; Dingwall, Heather L; Richmond, Brian G

2016-01-01

Fossil hominin footprints offer unique direct windows to the locomotor behaviors of our ancestors. These data could allow a clearer understanding of the evolution of human locomotion by circumventing issues associated with indirect interpretations of habitual locomotor patterns from fossil skeletal material. However, before we can use fossil hominin footprints to understand better the evolution of human locomotion, we must first develop an understanding of how locomotor biomechanics are preserved in, and can be inferred from, footprint morphologies. In this experimental study, 41 habitually barefoot modern humans created footprints under controlled conditions in which variables related to locomotor biomechanics could be quantified. Measurements of regional topography (depth) were taken from 3D models of those footprints, and principal components analysis was used to identify orthogonal axes that described the largest proportions of topographic variance within the human experimental sample. Linear mixed effects models were used to quantify the influences of biomechanical variables on the first five principal axes of footprint topographic variation, thus providing new information on the biomechanical variables most evidently expressed in the morphology of human footprints. The footprint's overall depth was considered as a confounding variable, since biomechanics may be linked to the extent to which a substrate deforms. Three of five axes showed statistically significant relationships with variables related to both locomotor biomechanics and substrate displacement; one axis was influenced only by biomechanics and another only by the overall depth of the footprint. Principal axes of footprint morphological variation were significantly related to gait type (walking or running), kinematics of the hip and ankle joints and the distribution of pressure beneath the foot. These results provide the first quantitative framework for developing hypotheses regarding the

Biomechanics-based in silico medicine: the manifesto of a new science.

Science.gov (United States)

Viceconti, Marco

2015-01-21

In this perspective article we discuss the role of contemporary biomechanics in the light of recent applications such as the development of the so-called Virtual Physiological Human technologies for physiology-based in silico medicine. In order to build Virtual Physiological Human (VPH) models, computer models that capture and integrate the complex systemic dynamics of living organisms across radically different space-time scales, we need to re-formulate a vast body of existing biology and physiology knowledge so that it is formulated as a quantitative hypothesis, which can be expressed in mathematical terms. Once the predictive accuracy of these models is confirmed against controlled experiments and against clinical observations, we will have VPH model that can reliably predict certain quantitative changes in health status of a given patient, but also, more important, we will have a theory, in the true meaning this word has in the scientific method. In this scenario, biomechanics plays a very important role, biomechanics is one of the few areas of life sciences where we attempt to build full mechanistic explanations based on quantitative observations, in other words, we investigate living organisms like physical systems. This is in our opinion a Copernican revolution, around which the scope of biomechanics should be re-defined. Thus, we propose a new definition for our research domain "Biomechanics is the study of living organisms as mechanistic systems". Copyright © 2014 Elsevier Ltd. All rights reserved.

No effects of functional exercise therapy on walking biomechanics in patients with knee osteoarthritis

DEFF Research Database (Denmark)

Henriksen, Marius; Klokker, Louise; Bartholdy, Cecilie

2016-01-01

AIM: To assess the effects of a functional and individualised exercise programme on gait biomechanics during walking in people with knee OA. METHODS: Sixty participants were randomised to 12 weeks of facility-based functional and individualised neuromuscular exercise therapy (ET), 3 sessions per...... limited confidence in the findings due to multiple statistical tests and lack of biomechanical logics. Therefore we conclude that a 12-week supervised individualised neuromuscular exercise programme has no effects on gait biomechanics. Future studies should focus on exercise programmes specifically...

Adhesive strength of hydroxyl apatite(HA) coating and biomechanics behavior of HA-coated prosthesis:an experimental study

OpenAIRE

Tian-yang ZHANG; Yong-hong DUAN; Shu ZHU; Jin-yu ZHU; Qing-sheng ZHU

2011-01-01

Objective To explore the influence of adhesive strength of hydroxyapatite(HA) coating on the post-implantation stability of HA-coated prosthesis.Methods The adhesive strength and biomechanics behavior of HA coating were studied by histopathological observation,material parameters and biomechanical testing,the titanium(Ti)-coated prosthesis was employed as control.Results Scratch test showed that the adhesive strength of HA coating was significantly lower than that of Ti coating(P < 0.01).Hist...

Biomechanics of compensatory mechanisms in spinal-pelvic complex

Science.gov (United States)

Ivanov, D. V.; Hominets, V. V.; Kirillova, I. V.; Kossovich, L. Yu; Kudyashev, A. L.; Teremshonok, A. V.

2018-04-01

3D geometric solid computer model of spinal-pelvic complex was constructed on the basis of computed tomography and full body X-ray in standing position data. The constructed model was used for biomechanical analysis of compensatory mechanisms arising in the spine with anteversion and retroversion of the pelvis. The results of numerical biomechanical 3D modeling are in good agreement with the clinical data.

Biomechanical ToolKit: Open-source framework to visualize and process biomechanical data.

Science.gov (United States)

Barre, Arnaud; Armand, Stéphane

2014-04-01

C3D file format is widely used in the biomechanical field by companies and laboratories to store motion capture systems data. However, few software packages can visualize and modify the integrality of the data in the C3D file. Our objective was to develop an open-source and multi-platform framework to read, write, modify and visualize data from any motion analysis systems using standard (C3D) and proprietary file formats (used by many companies producing motion capture systems). The Biomechanical ToolKit (BTK) was developed to provide cost-effective and efficient tools for the biomechanical community to easily deal with motion analysis data. A large panel of operations is available to read, modify and process data through C++ API, bindings for high-level languages (Matlab, Octave, and Python), and standalone application (Mokka). All these tools are open-source and cross-platform and run on all major operating systems (Windows, Linux, MacOS X). Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

The effect of trochlear dysplasia on patellofemoral biomechanics: a cadaveric study with simulated trochlear deformities.

Science.gov (United States)

Van Haver, Annemieke; De Roo, Karel; De Beule, Matthieu; Labey, Luc; De Baets, Patrick; Dejour, David; Claessens, Tom; Verdonk, Peter

2015-06-01

Trochlear dysplasia appears in different geometrical variations. The Dejour classification is widely used to grade the severity of trochlear dysplasia and to decide on treatment. To investigate the effect of trochlear dysplasia on patellofemoral biomechanics and to determine if different types of trochlear dysplasia have different effects on patellofemoral biomechanics. Controlled laboratory study. Trochlear dysplasia was simulated in 4 cadaveric knees by replacing the native cadaveric trochlea with different types of custom-made trochlear implants, manufactured with 3-dimensional printing. For each knee, 5 trochlear implants were designed: 1 implant simulated the native trochlea (control condition), and 4 implants simulated 4 types of trochlear dysplasia. The knees were subjected to 3 biomechanical tests: a squat simulation, an open chain extension simulation, and a patellar stability test. The patellofemoral kinematics, contact area, contact pressure, and stability were compared between the control condition (replica implants) and the trochlear dysplastic condition and among the subgroups of trochlear dysplasia. The patellofemoral joint in the trochlear dysplastic group showed increased internal rotation, lateral tilt, and lateral translation; increased contact pressures; decreased contact areas; and decreased stability when compared with the control group. Within the trochlear dysplastic group, the implants graded as Dejour type D showed the largest deviations for the kinematical parameters, and the implants graded as Dejour types B and D showed the largest deviations for the patellofemoral contact areas and pressures. Patellofemoral kinematics, contact area, contact pressure, and stability are significantly affected by trochlear dysplasia. Of all types of trochlear dysplasia, the models characterized with a pronounced trochlear bump showed the largest deviations in patellofemoral biomechanics. Investigating the relationship between the shape of the trochlea and

An aetiological study on spondylolysis from a biomechanical aspect.

Science.gov (United States)

Ichikawa, N.; Ohara, Y.; Morishita, T.; Taniguichi, Y.; Koshikawa, A.; Matsukura, N.

1982-01-01

The authors report clinical studies on lumbar disorders (clinical symptoms, X-ray findings) in athletes in various sports. The sport items were divided into three groups according to the main dynamic load applied to the lumbar region. As a result, over 60% of the athletes suffered from "lumbago", and among them spondylolysis reached the high rate of 27%. Arising from these clinical observations, we performed biomechanical laboratory analyses on human cadaver material, axial compression and rotational bending. Our results suggest that the incidence of spondylolysis depends upon the extent and direction of the loads. Images Fig. 4 Fig. 5 Fig. 8 Fig. 9 Fig. 10 PMID:7139222

Head Impact Biomechanics in Women's College Soccer.

Science.gov (United States)

Lynall, Robert C; Clark, Michael D; Grand, Erin E; Stucker, Jaclyn C; Littleton, Ashley C; Aguilar, Alain J; Petschauer, Meredith A; Teel, Elizabeth F; Mihalik, Jason P

2016-09-01

There are limited nonlaboratory soccer head impact biomechanics data. This is surprising given soccer's global popularity. Epidemiological data suggest that female college soccer players are at a greater concussion injury risk than their male counterparts. Therefore, the purposes of our study were to quantify head impact frequency and magnitude during women's soccer practices and games in the National Collegiate Athletic Association and to characterize these data across event type, playing position, year on the team, and segment of game (first and second halves). Head impact biomechanics were collected from female college soccer players (n = 22; mean ± SD age = 19.1 ± 0.1 yr, height = 168.0 ± 3.5 cm, mass = 63.7 ± 6.0 kg). We employed a helmetless head impact measurement device (X2 Biosystems xPatch) before each competition and practice across a single season. Peak linear and rotational accelerations were categorized based on impact magnitude and subsequently analyzed using appropriate nonparametric analyses. Overall, women's college soccer players experience approximately seven impacts per 90 min of game play. The overwhelming majority (~90%) of all head impacts were categorized into our mildest linear acceleration impact classification (10g-20g). Interestingly, a higher percentage of practice impacts in the 20g-40g range compared with games (11% vs 7%) was observed. Head impact biomechanics studies have provided valuable insights into understanding collision sports and for informing evidence-based rule and policy changes. These have included changing the football kickoff, ice hockey body checking ages, and head-to-head hits in both sports. Given soccer's global popularity, and the growing public concern for the potential long-term neurological implications of collision and contact sports, studying soccer has the potential to impact many athletes and the sports medicine professionals caring for them.

Novel in Vitro Modification of Bone for an Allograft with Improved Toughness Osteoconductivity

Science.gov (United States)

2015-06-01

age and sex groups and then analyzed separately. The last row summarizes the results of post-hoc analysis. K0 ∆amax Kmax R Age p=0.0783 NS5 NS5...bone: evaluation by R-curves. Bone, 2004. 35(6): p. 1240-6. 18. Reddy, G.K., Glucose-mediated in vitro glycation modulates biomechanical integrity of

Investigation of the influence of design details on short implant biomechanics using colorimetric photoelastic analysis: a pilot study

Directory of Open Access Journals (Sweden)

João César Zielak

Full Text Available Introduction : The clinical survival of a dental implant is directly related to its biomechanical behavior. Since short implants present lower bone/implant contact area, their design may be more critical to stress distribution to surrounding tissues. Photoelastic analysis is a biomechanical method that uses either simple qualitative results or complex calculations for the acquisition of quantitative data. In order to simplify data acquisition, we performed a pilot study to demonstrate the investigation of biomechanics via correlation of the findings of colorimetric photoelastic analysis (stress transition areas; STAs of design details between two types of short dental implants under axial loads. Methods Implants were embedded in a soft photoelastic resin and axially loaded with 10 and 20 N of force. Implant design features were correlated with the STAs (mm2 of the colored fringes of colorimetric photoelastic analysis. Results Under a 10 N load, the surface area of the implants was directly related to STA, whereas under a 20 N load, the surface area and thread height were inversely related to STA. Conclusion A smaller external thread height seemed to improve the biomechanical performance of the short implants investigated.

An Evidence-Based Videotaped Running Biomechanics Analysis.

Science.gov (United States)

Souza, Richard B

2016-02-01

Running biomechanics play an important role in the development of injuries. Performing a running biomechanics analysis on injured runners can help to develop treatment strategies. This article provides a framework for a systematic video-based running biomechanics analysis plan based on the current evidence on running injuries, using 2-dimensional (2D) video and readily available tools. Fourteen measurements are proposed in this analysis plan from lateral and posterior video. Identifying simple 2D surrogates for 3D biomechanic variables of interest allows for widespread translation of best practices, and have the best opportunity to impact the highly prevalent problem of the injured runner. Copyright © 2016 Elsevier Inc. All rights reserved.

Translating ocular biomechanics into clinical practice: current state and future prospects.

Science.gov (United States)

Girard, Michaël J A; Dupps, William J; Baskaran, Mani; Scarcelli, Giuliano; Yun, Seok H; Quigley, Harry A; Sigal, Ian A; Strouthidis, Nicholas G

2015-01-01

Biomechanics is the study of the relationship between forces and function in living organisms and is thought to play a critical role in a significant number of ophthalmic disorders. This is not surprising, as the eye is a pressure vessel that requires a delicate balance of forces to maintain its homeostasis. Over the past few decades, basic science research in ophthalmology mostly confirmed that ocular biomechanics could explain in part the mechanisms involved in almost all major ophthalmic disorders such as optic nerve head neuropathies, angle closure, ametropia, presbyopia, cataract, corneal pathologies, retinal detachment and macular degeneration. Translational biomechanics in ophthalmology, however, is still in its infancy. It is believed that its use could make significant advances in diagnosis and treatment. Several translational biomechanics strategies are already emerging, such as corneal stiffening for the treatment of keratoconus, and more are likely to follow. This review aims to cultivate the idea that biomechanics plays a major role in ophthalmology and that the clinical translation, lead by collaborative teams of clinicians and biomedical engineers, will benefit our patients. Specifically, recent advances and future prospects in corneal, iris, trabecular meshwork, crystalline lens, scleral and lamina cribrosa biomechanics are discussed.

Corneal Biomechanics in Ectatic Diseases: Refractive Surgery Implications

Science.gov (United States)

Ambrósio, Jr, Renato; Correia, Fernando Faria; Lopes, Bernardo; Salomão, Marcella Q.; Luz, Allan; Dawson, Daniel G.; Elsheikh, Ahmed; Vinciguerra, Riccardo; Vinciguerra, Paolo; Roberts, Cynthia J.

2017-01-01

Background: Ectasia development occurs due to a chronic corneal biomechanical decompensation or weakness, resulting in stromal thinning and corneal protrusion. This leads to corneal steepening, increase in astigmatism, and irregularity. In corneal refractive surgery, the detection of mild forms of ectasia pre-operatively is essential to avoid post-operative progressive ectasia, which also depends on the impact of the procedure on the cornea. Method: The advent of 3D tomography is proven as a significant advancement to further characterize corneal shape beyond front surface topography, which is still relevant. While screening tests for ectasia had been limited to corneal shape (geometry) assessment, clinical biomechanical assessment has been possible since the introduction of the Ocular Response Analyzer (Reichert Ophthalmic Instruments, Buffalo, USA) in 2005 and the Corvis ST (Oculus Optikgeräte GmbH, Wetzlar, Germany) in 2010. Direct clinical biomechanical evaluation is recognized as paramount, especially in detection of mild ectatic cases and characterization of the susceptibility for ectasia progression for any cornea. Conclusions: The purpose of this review is to describe the current state of clinical evaluation of corneal biomechanics, focusing on the most recent advances of commercially available instruments and also on future developments, such as Brillouin microscopy. PMID:28932334

Advanced Computational Methods in Bio-Mechanics.

Science.gov (United States)

Al Qahtani, Waleed M S; El-Anwar, Mohamed I

2018-04-15

A novel partnership between surgeons and machines, made possible by advances in computing and engineering technology, could overcome many of the limitations of traditional surgery. By extending surgeons' ability to plan and carry out surgical interventions more accurately and with fewer traumas, computer-integrated surgery (CIS) systems could help to improve clinical outcomes and the efficiency of healthcare delivery. CIS systems could have a similar impact on surgery to that long since realised in computer-integrated manufacturing. Mathematical modelling and computer simulation have proved tremendously successful in engineering. Computational mechanics has enabled technological developments in virtually every area of our lives. One of the greatest challenges for mechanists is to extend the success of computational mechanics to fields outside traditional engineering, in particular to biology, the biomedical sciences, and medicine. Biomechanics has significant potential for applications in orthopaedic industry, and the performance arts since skills needed for these activities are visibly related to the human musculoskeletal and nervous systems. Although biomechanics is widely used nowadays in the orthopaedic industry to design orthopaedic implants for human joints, dental parts, external fixations and other medical purposes, numerous researches funded by billions of dollars are still running to build a new future for sports and human healthcare in what is called biomechanics era.

Applications of biomechanics for prevention of work-related musculoskeletal disorders.

Science.gov (United States)

Garg, Arun; Kapellusch, Jay M

2009-01-01

This paper summarises applications of biomechanical principles and models in industry to control musculoskeletal disorders of the low back and upper extremity. Applications of 2-D and 3-D biomechanical models to estimate compressive force on the low back, the strength requirements of jobs, application of guidelines for overhead work and application of strain index and threshold limit value to address distal upper extremity musculoskeletal disorders are presented. Several case studies applied in the railroad industry, manufacturing, healthcare and warehousing are presented. Finally, future developments needed for improved biomechanical applications in industry are discussed. The information presented will be of value to practising ergonomists to recognise how biomechanics has played a significant role in identifying causes of musculoskeletal disorders and controlling them in the workplace. In particular, the information presented will help practising ergonomists with how physical stresses can be objectively quantified.

Biomechanically acquired foot types

International Nuclear Information System (INIS)

Weissman, S.D.

1989-01-01

Over the years, orthopedics of the foot has gone through many stages and phases, each of which has spawned a whole vocabulary of its own. According the author, today we are in the biomechanical age, which represents a step forward in understanding the mechanisms governing the functions of the lower extremity. A great deal of scientific research on the various foot types and pathological entities is now being performed. This paper discusses how, from a radiographic point of view, a knowledge of certain angular relationships must be achieved before one can perform a biomechanical evaluation. In order to validate the gross clinical findings, following an examination of a patient, a biomechanical evaluation can be performed on the radiographs taken. It must be remembered, however, that x-rays are never the sole means of making a diagnosis. They are just one of many findings that must be put together to arrive at a pertinent clinical assessment or diagnosis

Biomechanics of the elbow joint in tennis players and relation to pathology.

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Eygendaal, Denise; Rahussen, F Th G; Diercks, R L

2007-11-01

Elbow injuries constitute a sizeable percentage of tennis injuries. A basic understanding of biomechanics of tennis and analysis of the forces, loads and motions of the elbow during tennis will improve the understanding of the pathophysiology of these injuries. All different strokes in tennis have a different repetitive biomechanical nature that can result in tennis-related injuries. In this article, a biomechanically-based evaluation of tennis strokes is presented. This overview includes all tennis-related pathologies of the elbow joint, whereby the possible relation of biomechanics to pathology is analysed, followed by treatment recommendations.

Occupational stress and biomechanical risk in a high fashion clothing company.

Science.gov (United States)

Forcella, Laura; Bonfiglioli, Roberta; Cutilli, Piero; Antonucci, Andrea; Di Donato, Angela; Siciliano, Eugenio; Cortini, Michela; Violante, Francesco Saverio; Boscolo, Paolo

2012-01-01

Psychosocial discomfort may amplify job-related risk factors. The aim of this study is to evaluate job stress in a high fashion clothing company with upper limb biomechanical overload due to repetitive and forceful manual activities. Biomechanical risk was analyzed and in part reduced using the OCRA Check list. A total of 518 workers (433 females and 85 males) were investigated to determine anxiety (by STAI 1 and 2), occupational stress (using the Italian version of the Karasek Job Content Questionnaire) and perception of symptoms. Final biomechanical assessment did not reveal high risk jobs, except for cutting. Although the perception of anxiety and job insecurity was within the normal range, all the workers showed a high level of job strain (correlated with the perception of symptoms) due, probably, to very low decision latitude. It was suggested that job strain may increase the perception of symptoms. Moreover, the result of this study indicates that musculoskeletal overload has to be further analyzed since its low level is not in agreement with the level of discomfort due to the repetitive tasks.

Cycling biomechanics: a literature review.

Science.gov (United States)

Wozniak Timmer, C A

1991-01-01

Submitted in partial fulfillment for a Master of Science degree at the University of Pittsburgh, School of Health Related Professions, Pittsburgh, PA 1.5213 This review of current literature on cycling biomechanics emphasizes lower extremity muscle actions and joint excursions, seat height, pedal position, pedaling rate, force application, and pedaling symmetry. Guidelines are discussed for optimal seat height, pedal position, and pedaling rate. Force application in the power and recovery phases of cycling and the relationship of force application to pedaling symmetry are discussed. The need for a biomechanical approach to cycling exists since a great deal of the literature is primarily physiologic in nature. The purpose of this review is to make cyclists and their advisors aware of the biomechanics of cycling and guidelines to follow. This approach is also important because cycling is a very common form of exercise prescribed by physical therapists for clinic or home programs. Biomechanical aspects of cycling should be considered by cyclists at any level of participation and by physical therapists in order for goal-oriented, efficient cycling to occur. J Orthop Sports Phys Ther 1991;14(3):106-113.

Biomechanical factors associated with the risk of knee injury when ...

African Journals Online (AJOL)

Objectives. To systematically assess the literature investigating biomechanical knee injury risk factors when an individual lands from a jump. Data sources. Four electronic databases were searched for peer-reviewed English journals containing landing biomechanical studies published over 14 years (1990 - 2003).

Biomechanical pulping of kenaf

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Aziz Ahmed; Masood Akhtar; Gary C. Myers; Gary M. Scott

1999-01-01

The objective of this study was to investigate the effect of fungal pretreatment of whole kenaf prior to refining on refiner electrical energy consumption, paper strength, and optical properties. We also explored the suitability of whole kenaf biomechanical pulp for making newsprint in terms of ISO brightness and strength properties. Kenaf was sterilized by autoclaving...

Evaluation of corneal biomechanics in patients with keratectasia following LASIK using dynamic Scheimpflug analyzer.

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Ueki, Ryotaro; Maeda, Naoyuki; Fuchihata, Mutsumi; Asai, Tomoko; Koh, Shizuka; Fujimoto, Hisataka; Uematsu, Masafumi; Nishida, Kohji

2018-04-26

To investigate the corneal biomechanics in eyes with keratectasia following LASIK using a dynamic Scheimpflug analyzer. Case-Control study. The subjects in the study included 12 eyes with keratectasia after LASIK (KE), 24 eyes with keratoconus (KC), 17 eyes without keratectasia after LASIK (LASIK), and 34 eyes with normal corneas (Normal). Corneal biomechanics of the four groups were evaluated using a dynamic Scheimpflug analyzer. Compared with Normal (7.06 ± 0.54), the radius at the highest concavity (radius, mm) of LASIK (5.96 ± 0.76), KE (4.93 ± 0.61) and KC (5.39 ± 1.02) were significantly small. The Deflection Amplitude (HCDLA, mm) of Normal (0.94 ± 0.07) was significantly lower than those of KE (1.11 ± 0.10) and KC (1.06 ± 0.16), and was not significantly different from that of LASIK (0.98 ± 0.07). There were significant differences between LASIK and KE in radius and HCDLA (P biomechanical features evaluated using the dynamic Scheimpflug analyzer suggest that biomechanical properties in eyes with keratectasia, keratoconus, and LASIK are different from those of normal eyes. Although the biomechanics in eyes with keratectasia differs from that in eyes with LASIK, it is similar to that in eyes with keratoconus.

Cutiscan® - A new system of biomechanical evaluation of the skin in vivo - comparative study of use depending on the anatomical site

Directory of Open Access Journals (Sweden)

Catarina Rosado

2015-05-01

Full Text Available Skin is a complex biomaterial. One of its characteristics is anisotropy due to fiber alignment, resulting from prolonged exposure to a surrounding stress state. This property is important in experimental studies of skin biomechanics and in experimental dermatology. During the last decades, several devices have been developed to study the cutaneous physiology. The CutiScan®, one of the latest, provides information not only about the elastic and viscoelastic properties, but also on anisotropy and directionality of the skin. The aim of this study is to investigate the changes in the biomechanical properties of human skin due to the anatomical site, combined with a study on the benefits and limitations of the CutiScan®, and also comparing it with other more studied devices - the Cutometer® and the Reviscometer®. 20 volunteers were engaged in this investigation after an informed consent. Measurements were conducted in three different anatomical sites (forehead, forearm and leg with each device. Results showed that devices were able to identify significant differences among anatomical sites. The CutiScan® enabled a more complete assessment of skin’s biomechanical properties, since it provides real-time images and 360º elasticity curves that allowed the simultaneous study of viscoelasticity and anisotropy.

Perspectives on Sharing Models and Related Resources in Computational Biomechanics Research.

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Erdemir, Ahmet; Hunter, Peter J; Holzapfel, Gerhard A; Loew, Leslie M; Middleton, John; Jacobs, Christopher R; Nithiarasu, Perumal; Löhner, Rainlad; Wei, Guowei; Winkelstein, Beth A; Barocas, Victor H; Guilak, Farshid; Ku, Joy P; Hicks, Jennifer L; Delp, Scott L; Sacks, Michael; Weiss, Jeffrey A; Ateshian, Gerard A; Maas, Steve A; McCulloch, Andrew D; Peng, Grace C Y

2018-02-01

The role of computational modeling for biomechanics research and related clinical care will be increasingly prominent. The biomechanics community has been developing computational models routinely for exploration of the mechanics and mechanobiology of diverse biological structures. As a result, a large array of models, data, and discipline-specific simulation software has emerged to support endeavors in computational biomechanics. Sharing computational models and related data and simulation software has first become a utilitarian interest, and now, it is a necessity. Exchange of models, in support of knowledge exchange provided by scholarly publishing, has important implications. Specifically, model sharing can facilitate assessment of reproducibility in computational biomechanics and can provide an opportunity for repurposing and reuse, and a venue for medical training. The community's desire to investigate biological and biomechanical phenomena crossing multiple systems, scales, and physical domains, also motivates sharing of modeling resources as blending of models developed by domain experts will be a required step for comprehensive simulation studies as well as the enhancement of their rigor and reproducibility. The goal of this paper is to understand current perspectives in the biomechanics community for the sharing of computational models and related resources. Opinions on opportunities, challenges, and pathways to model sharing, particularly as part of the scholarly publishing workflow, were sought. A group of journal editors and a handful of investigators active in computational biomechanics were approached to collect short opinion pieces as a part of a larger effort of the IEEE EMBS Computational Biology and the Physiome Technical Committee to address model reproducibility through publications. A synthesis of these opinion pieces indicates that the community recognizes the necessity and usefulness of model sharing. There is a strong will to facilitate

Biomechanically Excited SMD Model of a Walking Pedestrian

DEFF Research Database (Denmark)

Zhang, Mengshi; Georgakis, Christos T.; Chen, Jun

2016-01-01

Through their biomechanical properties, pedestrians interact with the structures they occupy. Although this interaction has been recognized by researchers, pedestrians' biomechanical properties have not been fully addressed. In this paper, a spring-mass-damper (SMD) system, with a pair of biomech......Through their biomechanical properties, pedestrians interact with the structures they occupy. Although this interaction has been recognized by researchers, pedestrians' biomechanical properties have not been fully addressed. In this paper, a spring-mass-damper (SMD) system, with a pair...... produced the pedestrian's center of mass (COM) trajectories from the captured motion markers. The vertical COM trajectory was approximated to be the pedestrian SMD dynamic responses under the excitation of biomechanical forces. SMD model parameters of a pedestrian for a specific walking frequency were...... estimated from a known walking frequency and the pedestrian's weight, assuming that pedestrians always walk in displacement resonance and retain a constant damping ratio of 0.3. Thus, biomechanical forces were extracted using the measured SMD dynamic responses and the estimated SMD parameters. Extracted...

Biomechanical implant treatment complications: a systematic review of clinical studies of implants with at least 1 year of functional loading.

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Hsu, Yung-Ting; Fu, Jia-Hui; Al-Hezaimi, Khalid; Wang, Hom-Lay

2012-01-01

The aim of this article is to discuss the current literature available on the etiology and management of biomechanical complications of dental implant treatment. An electronic search of the PubMed database for English-language articles published before May 31, 2011, was performed based on a focus question: "How can biomechanical implant treatment complications be managed and identified?" The key words used were "dental implant," "etiology," "management," "excessive occlusal forces," "occlusal forces," "occlusion," "parafunctional habits," "biomechanical failure," "biomechanical complications," and "occlusal overloading." Clinical trials with a minimum of 10 implants followed for at least 1 year after functional loading were included. The initial electronic search identified 2,087 publications, most of which were eliminated, as they were animal studies, finite element analyses, bench-top studies, case reports, and literature reviews. After the titles, abstracts, and full text of 39 potentially eligible publications were reviewed, 15 studies were found to fulfill the inclusion criteria. Occlusal overloading was thought to be the primary etiologic factor in biomechanical implant treatment complications, which commonly included marginal bone loss, fracture of resin/ceramic veneers and porcelain, retention device or denture base fracture of implant-supported overdentures, loosening or fracture of abutment screws, and even implant failure. Occlusal overloading was positively associated with parafunctional habits such as bruxism. An appreciation of the intricacy of implant occlusion would allow clinicians to take a more preventive approach when performing implant treatment planning, as avoidance of implant overloading helps to ensure the long-term stability of implant-supported prostheses.

The application of finite element analysis in the skull biomechanics and dentistry.

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Prado, Felippe Bevilacqua; Rossi, Ana Cláudia; Freire, Alexandre Rodrigues; Ferreira Caria, Paulo Henrique

2014-01-01

Empirical concepts describe the direction of the masticatory stress dissipation in the skull. The scientific evidence of the trajectories and the magnitude of stress dissipation can help in the diagnosis of the masticatory alterations and the planning of oral rehabilitation in the different areas of Dentistry. The Finite Element Analysis (FEA) is a tool that may reproduce complex structures with irregular geometries of natural and artificial tissues of the human body because it uses mathematical functions that enable the understanding of the craniofacial biomechanics. The aim of this study was to review the literature on the advantages and limitations of FEA in the skull biomechanics and Dentistry study. The keywords of the selected original research articles were: Finite element analysis, biomechanics, skull, Dentistry, teeth, and implant. The literature review was performed in the databases, PUBMED, MEDLINE and SCOPUS. The selected books and articles were between the years 1928 and 2010. The FEA is an assessment tool whose application in different areas of the Dentistry has gradually increased over the past 10 years, but its application in the analysis of the skull biomechanics is scarce. The main advantages of the FEA are the realistic mode of approach and the possibility of results being based on analysis of only one model. On the other hand, the main limitation of the FEA studies is the lack of anatomical details in the modeling phase of the craniofacial structures and the lack of information about the material properties.

Physiological, biochemical, anthropometric, and biomechanical influences on exercise economy in humans

DEFF Research Database (Denmark)

Lundby, C; Montero, D; Gehrig, S

2017-01-01

and cycling EE within a single study. In 22 healthy males (VO2max range 45.5-72.1 mL·min-1·kg-1), no factor related to skeletal muscle structure (% slow-twitch fiber content, number of capillaries per fiber), mitochondrial properties (volume density, oxidative capacity, or mitochondrial efficiency...... were correlated (R2=.94; Pindividual running and cycling EE considering that during cycle ergometer exercise, the biomechanical influence on EE would be small because of the fixed......Interindividual variation in running and cycling exercise economy (EE) remains unexplained although studied for more than a century. This study is the first to comprehensively evaluate the importance of biochemical, structural, physiological, anthropometric, and biomechanical influences on running...

The use of the co-ordinate measuring machine for the study of three-dimensional biomechanics of the knee.

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Veselko, M; Jenko, M; Lipuscek, I

1998-07-01

Original methodology for the study of three-dimensional biomechanics of the knee is presented in the paper. Defining the geometry of the rigid body in the body-fixed reference frame and the orientation of the body-fixed reference frame in the global co-ordinate system are the theoretic basis. The data in the form of co-ordinates of the Cartesian frame are gathered by the co-ordinate measuring machine and analysed by specially computer program. The theory and a practical example of the study of the three-dimensional biomechanics of the knee are presented. Various possibilities of the use of the methodology are discussed.

Low-Back Biomechanics and Static Stability During Isometric Pushing

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Granata, Kevin P.; Bennett, Bradford C.

2006-01-01

Pushing and pulling tasks are increasingly prevalent in industrial workplaces. Few studies have investigated low-back biomechanical risk factors associated with pushing, and we are aware of none that has quantified spinal stability during pushing exertions. Data recorded from 11 healthy participants performing isometric pushing exertions demonstrated that trunk posture, vector force direction of the applied load, and trunk moment were influenced (p pushing task, and foot position. A biomechanical model was used to analyze the posture and hand force data gathered from the pushing exertions. Model results indicate that pushing exertions provide significantly (p pushing exertions. If one maintains stability by means of cocontraction, additional spinal load is thereby created, increasing the risk of overload injury. Thus it is important to consider muscle cocontraction when evaluating the biomechanics of pushing exertions. Potential applications of this research include improved assessment of biomechanical risk factors for the design of industrial pushing tasks. PMID:16435695

Biomechanical and Hemodynamic Measures of Right Ventricular Diastolic Function: Translating Tissue Biomechanics to Clinical Relevance.

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Jang, Sae; Vanderpool, Rebecca R; Avazmohammadi, Reza; Lapshin, Eugene; Bachman, Timothy N; Sacks, Michael; Simon, Marc A

2017-09-12

Right ventricular (RV) diastolic function has been associated with outcomes for patients with pulmonary hypertension; however, the relationship between biomechanics and hemodynamics in the right ventricle has not been studied. Rat models of RV pressure overload were obtained via pulmonary artery banding (PAB; control, n=7; PAB, n=5). At 3 weeks after banding, RV hemodynamics were measured using a conductance catheter. Biaxial mechanical properties of the RV free wall myocardium were obtained to extrapolate longitudinal and circumferential elastic modulus in low and high strain regions (E 1 and E 2 , respectively). Hemodynamic analysis revealed significantly increased end-diastolic elastance (E ed ) in PAB (control: 55.1 mm Hg/mL [interquartile range: 44.7-85.4 mm Hg/mL]; PAB: 146.6 mm Hg/mL [interquartile range: 105.8-155.0 mm Hg/mL]; P =0.010). Longitudinal E 1 was increased in PAB (control: 7.2 kPa [interquartile range: 6.7-18.1 kPa]; PAB: 34.2 kPa [interquartile range: 18.1-44.6 kPa]; P =0.018), whereas there were no significant changes in longitudinal E 2 or circumferential E 1 and E 2 . Last, wall stress was calculated from hemodynamic data by modeling the right ventricle as a sphere: stress=Pressure×radius2×thickness. RV pressure overload in PAB rats resulted in an increase in diastolic myocardial stiffness reflected both hemodynamically, by an increase in E ed , and biomechanically, by an increase in longitudinal E 1 . Modest increases in tissue biomechanical stiffness are associated with large increases in E ed . Hemodynamic measurements of RV diastolic function can be used to predict biomechanical changes in the myocardium. © 2017 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.

Harnessing biomechanics to develop cartilage regeneration strategies.

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Athanasiou, Kyriacos A; Responte, Donald J; Brown, Wendy E; Hu, Jerry C

2015-02-01

As this review was prepared specifically for the American Society of Mechanical Engineers H.R. Lissner Medal, it primarily discusses work toward cartilage regeneration performed in Dr. Kyriacos A. Athanasiou's laboratory over the past 25 years. The prevalence and severity of degeneration of articular cartilage, a tissue whose main function is largely biomechanical, have motivated the development of cartilage tissue engineering approaches informed by biomechanics. This article provides a review of important steps toward regeneration of articular cartilage with suitable biomechanical properties. As a first step, biomechanical and biochemical characterization studies at the tissue level were used to provide design criteria for engineering neotissues. Extending this work to the single cell and subcellular levels has helped to develop biochemical and mechanical stimuli for tissue engineering studies. This strong mechanobiological foundation guided studies on regenerating hyaline articular cartilage, the knee meniscus, and temporomandibular joint (TMJ) fibrocartilage. Initial tissue engineering efforts centered on developing biodegradable scaffolds for cartilage regeneration. After many years of studying scaffold-based cartilage engineering, scaffoldless approaches were developed to address deficiencies of scaffold-based systems, resulting in the self-assembling process. This process was further improved by employing exogenous stimuli, such as hydrostatic pressure, growth factors, and matrix-modifying and catabolic agents, both singly and in synergistic combination to enhance neocartilage functional properties. Due to the high cell needs for tissue engineering and the limited supply of native articular chondrocytes, costochondral cells are emerging as a suitable cell source. Looking forward, additional cell sources are investigated to render these technologies more translatable. For example, dermis isolated adult stem (DIAS) cells show potential as a source of

Changes in fatigue, multiplanar knee laxity, and landing biomechanics during intermittent exercise.

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Shultz, Sandra J; Schmitz, Randy J; Cone, John R; Henson, Robert A; Montgomery, Melissa M; Pye, Michele L; Tritsch, Amanda J

2015-05-01

Knee laxity increases during exercise. However, no one, to our knowledge, has examined whether these increases contribute to higher-risk landing biomechanics during prolonged, fatiguing exercise. To examine associations between changes in fatigue (measured as sprint time [SPTIME]), multiplanar knee laxity (anterior-posterior [APLAX], varus-valgus [VVLAX] knee laxity, and internal-external rotation [IERLAX]) knee laxity and landing biomechanics during prolonged, intermittent exercise. Descriptive laboratory study. Laboratory and gymnasium. A total of 30 male (age = 20.3 ± 2.0 years, height = 1.79 ± 0.05 m, mass = 75.2 ± 7.2 kg) and 29 female (age = 20.5 ± 2.3 years, height = 1.67 ± 0.08 m, mass = 61.8 ± 9.0 kg) competitive athletes. A 90-minute intermittent exercise protocol (IEP) designed to simulate the physiologic and biomechanical demands of a soccer match. We measured SPTIME, APLAX, and landing biomechanics before and after warm-up, every 15 minutes during the IEP, and every 15 minutes for 1 hour after the IEP. We measured VVLAX and IERLAX before and after the warm-up, at 45 and 90 minutes during the IEP, and at 30 minutes after the IEP. We used hierarchical linear modeling to examine associations between exercise-related changes in SPTIME and knee laxity with exercise-related changes in landing biomechanics while controlling for initial (before warm-up) knee laxity. We found that SPTIME had a more global effect on landing biomechanics in women than in men, resulting in a more upright landing and a reduction in landing forces and out-of-plane motions about the knee. As APLAX increased with exercise, women increased their knee internal-rotation motion (P = .02), and men increased their hip-flexion motion and energy-absorption (P = .006) and knee-extensor loads (P = .04). As VVLAX and IERLAX increased, women went through greater knee-valgus motion and dorsiflexion and absorbed more energy at the knee (P ≤ .05), whereas men were positioned in greater hip

Effects of a peracetic acid disinfection protocol on the biocompatibility and biomechanical properties of human patellar tendon allografts.

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Lomas, R J; Jennings, L M; Fisher, J; Kearney, J N

2004-01-01

Patellar tendon allografts, retrieved from cadaveric human donors, are widely used for replacement of damaged cruciate ligaments. In common with other tissue allografts originating from cadaveric donors, there are concerns regarding the potential for disease transmission from the donor to the recipient. Additionally, retrieval and subsequent processing protocols expose the graft to the risk of environmental contamination. For these reasons, disinfection or sterilisation protocols are necessary for these grafts before they are used clinically. A high-level disinfection protocol, utilising peracetic acid (PAA), has been developed and investigated for its effects on the biocompatibility and biomechanics of the patellar tendon allografts. PAA disinfection did not render the grafts either cytotoxic or liable to provoke an inflammatory response as assessed in vitro . However, the protocol was shown to increase the size of gaps between the tendon fibres in the matrix and render the grafts more susceptible to digestion with collagenase. Biomechanical studies of the tendons showed that PAA treatment had no effect on the ultimate tensile stress or Young's modulus of the tendons, and that ultimate strain was significantly higher in PAA treated tendons.

Effects of solid acellular type-I/III collagen biomaterials on in vitro and in vivo chondrogenesis of mesenchymal stem cells.

Science.gov (United States)

Gao, Liang; Orth, Patrick; Cucchiarini, Magali; Madry, Henning

2017-09-01

Type-I/III collagen membranes are advocated for clinical use in articular cartilage repair as being able of inducing chondrogenesis, a technique termed autologous matrix-induced chondrogenesis (AMIC). Area covered: The current in vitro and translational in vivo evidence for chondrogenic effects of solid acellular type-I/III collagen biomaterials. Expert commentary: In vitro, mesenchymal stem cells (MSCs) adhere to the fibers of the type-I/III collagen membrane. No in vitro study provides evidence that a type-I/III collagen matrix alone may induce chondrogenesis. Few in vitro studies compare the effects of type-I and type-II collagen scaffolds on chondrogenesis. Recent investigations suggest better chondrogenesis with type-II collagen scaffolds. A systematic review of the translational in vivo data identified one long-term study showing that covering of cartilage defects treated by microfracture with a type-I/III collagen membrane significantly enhanced the repair tissue volume compared with microfracture alone. Other in vivo evidence is lacking to suggest either improved histological structure or biomechanical function of the repair tissue. Taken together, there is a paucity of in vitro and preclinical in vivo evidence supporting the concept that solid acellular type-I/III collagen scaffolds may be superior to classical approaches to induce in vitro or in vivo chondrogenesis of MSCs.

Emulating facial biomechanics using multivariate partial least squares surrogate models.

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Wu, Tim; Martens, Harald; Hunter, Peter; Mithraratne, Kumar

2014-11-01

A detailed biomechanical model of the human face driven by a network of muscles is a useful tool in relating the muscle activities to facial deformations. However, lengthy computational times often hinder its applications in practical settings. The objective of this study is to replace precise but computationally demanding biomechanical model by a much faster multivariate meta-model (surrogate model), such that a significant speedup (to real-time interactive speed) can be achieved. Using a multilevel fractional factorial design, the parameter space of the biomechanical system was probed from a set of sample points chosen to satisfy maximal rank optimality and volume filling. The input-output relationship at these sampled points was then statistically emulated using linear and nonlinear, cross-validated, partial least squares regression models. It was demonstrated that these surrogate models can mimic facial biomechanics efficiently and reliably in real-time. Copyright © 2014 John Wiley & Sons, Ltd.

Influence of endodontic instrument-holder on sterilization efficacy. A pilot in-vitro study.

Directory of Open Access Journals (Sweden)

Angelo Carrizo

2013-08-01

Full Text Available Infection control is crucial in dentistry and various methods have been designed to assure its efficacy. However, little information exists regarding the influence it could have the instrument-holder of endodontic files. The aim of this research was to determine the influence of three instruments-holders on sterilization efficacy of endodontic files. Methods: A pilot in-vitro study. 60 endodontic files were contaminated by biomechanical preparation of extracted molars with periapical abscess, then processed according to the standard washing method. The endodontic files were divided into 3 groups (n=20 and assigned to 3 instrument-holders: Metallic box (MB, surgical gauze (SG and synthetic sponge (SS. Then, the files were packaged and sterilized by autoclaving (134°C/45min. Microbiological culture was performed in thioglycolate solution for each endodontic file (37ºC/5days. Results: The overall sterilization efficacy was 91.7%, 80% for MB, 100% for SS, and 95% for SG, with no statistically significant differences (p=0.06 between the groups. Conclusions: The lack of differences in the efficacy of sterilization may be due to the reduced sample; therefore, a full-size study is necessary to confirm this outcomes. The results of this study discourage the use of the MB as instrument-holder until a full-size study can confirm this data.

Biomechanics of Hybrid Anterior Cervical Fusion and Artificial Disc Replacement in 3-Level Constructs: An In Vitro Investigation

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Liao, Zhenhua; Fogel, Guy R.; Pu, Ting; Gu, Hongsheng; Liu, Weiqiang

2015-01-01

Background The ideal surgical approach for cervical disk disease remains controversial, especially for multilevel cervical disease. The purpose of this study was to investigate the biomechanics of the cervical spine after 3-level hybrid surgery compared with 3-level anterior cervical discectomy and fusion (ACDF). Material/Methods Eighteen human cadaveric spines (C2-T1) were evaluated under displacement-input protocol. After intact testing, a simulated hybrid construct or fusion construct was created between C3 to C6 and tested in the following 3 conditions: 3-level disc plate disc (3DPD), 3-level plate disc plate (3PDP), and 3-level plate (3P). Results Compared to intact, almost 65~80% of motion was successfully restricted at C3-C6 fusion levels (p0.05). 3PDP construct resulted in significant decrease of ROM at C3-C6 levels less than 3P (pbiomechanical advantages compared to fusion in normalizing motion. PMID:26529430

Analysis of occupational stress in a high fashion clothing factory with upper limb biomechanical overload.

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Forcella, Laura; Bonfiglioli, Roberta; Cutilli, Piero; Siciliano, Eugenio; Di Donato, Angela; Di Nicola, Marta; Antonucci, Andrea; Di Giampaolo, Luca; Boscolo, Paolo; Violante, Francesco Saverio

2012-07-01

To study job stress and upper limb biomechanical overload due to repetitive and forceful manual activities in a factory producing high fashion clothing. A total of 518 workers (433 women and 85 men) were investigated to determine anxiety, occupational stress (using the Italian version of the Karasek Job Content Questionnaire) and perception of symptoms (using the Italian version of the Somatization scale of Symptom Checklist SCL-90). Biomechanical overload was analyzed using the OCRA Check list. Biomechanical assessment did not reveal high-risk jobs, except for cutting. Although the perception of anxiety and job insecurity was within the normal range, all the workers showed a high level of job strain (correlated with the perception of symptoms) due to very low decision latitude. Occupational stress resulted partially in line with biomechanical risk factors; however, the perception of low decision latitude seems to play a major role in determining job strain. Interactions between physical and psychological factors cannot be demonstrated. Anyway, simultaneous long-term monitoring of occupational stress features and biomechanical overload could guide workplace interventions aimed at reducing the risk of adverse health effects.

Twenty-year trends of authorship and sampling in applied biomechanics research.

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Knudson, Duane

2012-02-01

This study documented the trends in authorship and sampling in applied biomechanics research published in the Journal of Applied Biomechanics and ISBS Proceedings. Original research articles of the 1989, 1994, 1999, 2004, and 2009 volumes of these serials were reviewed, excluding reviews, modeling papers, technical notes, and editorials. Compared to 1989 volumes, the mean number of authors per paper significantly increased (35 and 100%, respectively) in the 2009 volumes, along with increased rates of hyperauthorship, and a decline in rates of single authorship. Sample sizes varied widely across papers and did not appear to change since 1989.

Culture & differentiation of mesenchymal stem cell into osteoblast on degradable biomedical composite scaffold: In vitro study

Directory of Open Access Journals (Sweden)

Krishan G Jain

2015-01-01

Full Text Available Background & objectives: There is a significant bone tissue loss in patients from diseases and traumatic injury. The current autograft transplantation gold standard treatment has drawbacks, namely donor site morbidity and limited supply. The field of tissue engineering has emerged with a goal to provide alternative sources for transplantations to bridge this gap between the need and lack of bone graft. The aim of this study was to prepare biocomposite scaffolds based on chitosan (CHT, polycaprolactone (PCL and hydroxyapatite (HAP by freeze drying method and to assess the role of scaffolds in spatial organization, proliferation, and osteogenic differentiation of human mesenchymal stem cells (hMSCs in vitro, in order to achieve bone graft substitutes with improved physical-chemical and biological properties. Methods: Pure chitosan (100CHT and composites (40CHT/HAP, 30CHT/HAP/PCL and 25CHT/HAP/PCL scaffolds containing 40, 30, 25 parts per hundred resin (phr filler, respectively in acetic acid were freeze dried and the porous foams were studied for physicochemical and in vitro biological properties. Results: Scanning electron microscope (SEM images of the scaffolds showed porous microstructure (20-300 μm with uniform pore distribution in all compositions. Materials were tested under compressive load in wet condition (using phosphate buffered saline at pH 7.4. The in vitro studies showed that all the scaffold compositions supported mesenchymal stem cell attachment, proliferation and differentiation as visible from SEM images, [3-(4,5-dimethylthiazole-2-yl-2,5-diphenyltetrazolium bromide] (MTT assay, alkaline phosphatase (ALP assay and quantitative reverse transcription (qRT-PCR. Interpretation & conclusions: Scaffold composition 25CHT/HAP/PCL showed better biomechanical and osteoinductive properties as evident by mechanical test and alkaline phosphatase activity and osteoblast specific gene expression studies. This study suggests that this novel

Biomechanics of Spider Silks

Science.gov (United States)

2006-03-02

water and deformation conditions. Such fibres [Nexia ’ biosteel ’ silk ] were spun from recombinant silk ’cloned’ from Spidroin II and indeed show 67...SUBTITLE 5. FUNDING NUMBERS Biomechanics of Spider Silks F49620-03-1-0111 6. AUTHOR(S) Fritz Vollrath 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES...Perform Pro, WHSIDIOR, Oct 94 COVER SHEET FINAL (3rd Year) Report to AFOSR on: BIOMECHANICS OF SPIDER SILKS Fritz Vollrath, Oxford University, England

The biomechanics of seed germination.

Science.gov (United States)

Steinbrecher, Tina; Leubner-Metzger, Gerhard

2017-02-01

From a biomechanical perspective, the completion of seed (and fruit) germination depends on the balance of two opposing forces: the growth potential of the embryonic axis (radicle-hypocotyl growth zone) and the restraint of the seed-covering layers (endosperm, testa, and pericarp). The diverse seed tissues are composite materials which differ in their dynamic properties based on their distinct cell wall composition and water uptake capacities. The biomechanics of embryo cell growth during seed germination depend on irreversible cell wall loosening followed by water uptake due to the decreasing turgor, and this leads to embryo elongation and eventually radicle emergence. Endosperm weakening as a prerequisite for radicle emergence is a widespread phenomenon among angiosperms. Research into the biochemistry and biomechanics of endosperm weakening has demonstrated that the reduction in puncture force of a seed's micropylar endosperm is environmentally and hormonally regulated and involves tissue-specific expression of cell wall remodelling proteins such as expansins, diverse hydrolases, and the production of directly acting apoplastic reactive oxygen. The endosperm-weakening biomechanics and its underlying cell wall biochemistry differ between the micropylar (ME) and chalazal (CE) endosperm domains. In the ME, they involve cell wall loosening, cell separation, and programmed cell death to provide decreased and localized ME tissue resistance, autolysis, and finally the formation of an ME hole required for radicle emergence. Future work will further unravel the molecular mechanisms, environmental regulation, and evolution of the diverse biomechanical cell wall changes underpinning the control of germination by endosperm weakening. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Biomechanics of Artificial Disc Replacements Adjacent to a 2-Level Fusion in 4-Level Hybrid Constructs: An In Vitro Investigation

Science.gov (United States)

Liao, Zhenhua; Fogel, Guy R.; Wei, Na; Gu, Hongsheng; Liu, Weiqiang

2015-01-01

Background The ideal procedure for multilevel cervical degenerative disc diseases remains controversial. Recent studies on hybrid surgery combining anterior cervical discectomy and fusion (ACDF) and artificial cervical disc replacement (ACDR) for 2-level and 3-level constructs have been reported in the literature. The purpose of this study was to estimate the biomechanics of 3 kinds of 4-level hybrid constructs, which are more likely to be used clinically compared to 4-level arthrodesis. Material/Methods Eighteen human cadaveric spines (C2–T1) were evaluated in different testing conditions: intact, with 3 kinds of 4-level hybrid constructs (hybrid C3–4 ACDR+C4–6 ACDF+C6–7ACDR; hybrid C3–5ACDF+C5–6ACDR+C6–7ACDR; hybrid C3–4ACDR+C4–5ACDR+C5–7ACDF); and 4-level fusion. Results Four-level fusion resulted in significant decrease in the C3–C7 ROM compared with the intact spine. The 3 different 4-level hybrid treatment groups caused only slight change at the instrumented levels compared to intact except for flexion. At the adjacent levels, 4-level fusion resulted in significant increase of contribution of both upper and lower adjacent levels. However, for the 3 hybrid constructs, significant changes of motion increase far lower than 4P at adjacent levels were only noted in partial loading conditions. No destabilizing effect or hypermobility were observed in any 4-level hybrid construct. Conclusions Four-level fusion significantly eliminated motion within the construct and increased motion at the adjacent segments. For all 3 different 4-level hybrid constructs, ACDR normalized motion of the index segment and adjacent segments with no significant hypermobility. Compared with the 4-level ACDF condition, the artificial discs in 4-level hybrid constructs had biomechanical advantages compared to fusion in normalizing adjacent level motion. PMID:26694835

Patellar Tendon Repair Augmentation With a Knotless Suture Anchor Internal Brace: A Biomechanical Cadaveric Study.

Science.gov (United States)

Rothfeld, Alex; Pawlak, Amanda; Liebler, Stephenie A H; Morris, Michael; Paci, James M

2018-04-01

Patellar tendon repair with braided polyethylene suture alone is subject to knot slippage and failure. Several techniques to augment the primary repair have been described. Purpose/Hypothesis: The purpose was to evaluate a novel patellar tendon repair technique augmented with a knotless suture anchor internal brace with suture tape (SAIB). The hypothesis was that this technique would be biomechanically superior to a nonaugmented repair and equivalent to a standard augmentation with an 18-gauge steel wire. Controlled laboratory study. Midsubstance patellar tendon tears were created in 32 human cadaveric knees. Two comparison groups were created. Group 1 compared #2 supersuture repair without augmentation to #2 supersuture repair with SAIB augmentation. Group 2 compared #2 supersuture repair with an 18-gauge stainless steel cerclage wire augmentation to #2 supersuture repair with SAIB augmentation. The specimens were potted and biomechanically loaded on a materials testing machine. Yield load, maximum load, mode of failure, plastic displacement, elastic displacement, and total displacement were calculated for each sample. Standard statistical analysis was performed. There was a statistically significant increase in the mean ± SD yield load and maximum load in the SAIB augmentation group compared with supersuture alone (mean yield load: 646 ± 202 N vs 229 ± 60 N; mean maximum load: 868 ± 162 N vs 365 ± 54 N; P augmented repairs (mean yield load: 495 ± 213 N vs 566 ± 172 N; P = .476; mean maximum load: 737 ± 210 N vs 697 ± 130 N; P = .721). Patellar tendon repair augmented with SAIB is biomechanically superior to repair without augmentation and is equivalent to repair with augmentation with an 18-gauge stainless steel cerclage wire. This novel patellar tendon repair augmentation is equivalent to standard 18-gauge wire augmentation at time zero. It does not require a second surgery for removal, and it is biomechanically superior to primary repair alone.

Dance band on the Titanic: biomechanical signaling in cardiac hypertrophy.

Science.gov (United States)

Sussman, Mark A; McCulloch, Andrew; Borg, Thomas K

2002-11-15

Biomechanical signaling is a complex interaction of both intracellular and extracellular components. Both passive and active components are involved in the extracellular environment to signal through specific receptors to multiple signaling pathways. This review provides an overview of extracellular matrix, specific receptors, and signaling pathways for biomechanical stimulation in cardiac hypertrophy.

Forward lunge knee biomechanics before and after partial meniscectomy

DEFF Research Database (Denmark)

Hall, Michelle; Nielsen, Jonas Høberg; Holsgaard-Larsen, Anders

2015-01-01

partial meniscectomy (APM) on knee joint mechanics. The purpose of this study was to evaluate changes in knee joint biomechanics during a forward lunge in patients with a suspected degenerative meniscal tear from before to three months after APM. METHODS: Twenty-two patients (35-55years old......) with a suspected degenerative medial meniscal tear participated in this study. Three dimensional knee biomechanics were assessed on the injured and contralateral leg before and three months after APM. The visual analogue scale was used to assess knee pain and the Knee Injury Osteoarthritis Outcome Score was used...

Smart Materials in Structural Health Monitoring, Control and Biomechanics

CERN Document Server

Soh, Chee-Kiong; Bhalla, Suresh

2012-01-01

"Smart Materials in Structural Health Monitoring, Control and Biomechanics" presents the latest developments in structural health monitoring, vibration control and biomechanics using smart materials. The book mainly focuses on piezoelectric, fibre optic and ionic polymer metal composite materials. It introduces concepts from the very basics and leads to advanced modelling (analytical/ numerical), practical aspects (including software/ hardware issues) and case studies spanning civil, mechanical and aerospace structures, including bridges, rocks and underground structures. This book is intended for practicing engineers, researchers from academic and R&D institutions and postgraduate students in the fields of smart materials and structures, structural health monitoring, vibration control and biomedical engineering. Professor Chee-Kiong Soh and Associate Professor Yaowen Yang both work at the School of Civil and Environmental Engineering, Nanyang Technological University, Singapore. Dr. Suresh Bhalla is an A...

Paralympic sport: an emerging area for research and consultancy in sports biomechanics.

Science.gov (United States)

Keogh, Justin W L

2011-09-01

The Paralympic Games are the pinnacle of sport for many athletes with a disability. The overall purpose of this paper is to highlight the role that the field of sports biomechanics specifically (and sports science in general) may play in improving performance in various summer Paralympic sports through research and consultancy. To achieve this broad aim, this review provides some history and background on the Summer Paralympic Games, discusses the eligibility and classification rules, describes the potential for the constraints-led approach of dynamical systems theory to inform practice and research in this area, and reviews selected studies examining the biomechanics of the primary forms of Paralympic locomotion. Some recommendations on how sports biomechanics can help facilitate improvements in Paralympic athletic performance through applied research and consultancy are provided, along with commentary on what may be some of the most important issues addressing Paralympic sport.

Biomechanics: basic and applied research

International Nuclear Information System (INIS)

Bergmann, G.; Rohlmann, A.; Koelbel, R.

1987-01-01

This volume presents the state of the art in biomechanics. The most recent achievements of biomechanical research in the fields of orthopaedics, dynamics of the musculoskeletal system, hard and soft tissues, rehabilitation, sports, cardiovascular problems and research methodology have been selected and edited by a distinguished panel of reviewers. The material is such that the volume will serve as a reference for many years for bioengineers, sports scientists, clinicians and clinical researchers in rehabilitation, orthopaedics and cardiovascular surgery

Corneal biomechanical properties after laser-assisted in situ keratomileusis and photorefractive keratectomy

Directory of Open Access Journals (Sweden)

Hwang ES

2017-10-01

Full Text Available Eileen S Hwang,1 Brian C Stagg,1 Russell Swan,1 Carlton R Fenzl,1 Molly McFadden,2 Valliammai Muthappan,1 Luis Santiago-Caban,1 Mark D Mifflin,1 Majid Moshirfar1,3 1Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, 2Department of Internal Medicine, University of Utah, Salt Lake City, 3HDR Research Center, Hoopes Vision, Draper, UT, USA Background: The purpose of this study was to evaluate the effects of laser-assisted in situ keratomileusis (LASIK and photorefractive keratectomy (PRK on corneal biomechanical properties.Methods: We used the ocular response analyzer to measure corneal hysteresis (CH and corneal resistance factor (CRF before and after refractive surgery.Results: In all, 230 eyes underwent LASIK and 115 eyes underwent PRK without mitomycin C (MMC. Both procedures decreased CH and CRF from baseline. When MMC was used after PRK in 20 eyes, it resulted in lower corneal biomechanical properties at 3 months when compared to the other procedures, but all three procedures had similar values at 12 months.Conclusion: Significant but similar decreases in corneal biomechanical properties after LASIK, PRK without MMC, and PRK with MMC were noted. Keywords: corneal biomechanics, photorefractive keratectomy, laser-assisted in situ keratomileusis, corneal hysteresis, corneal resistance factor, mitomycin C

Comparison of transverse wires and half pins in Taylor Spatial Frame: A biomechanical study

OpenAIRE

Khurana, Ashish; Byrne, Carlton; Evans, Sam; Tanaka, Hiro; Haraharan, Kartik

2010-01-01

Abstract Background The aim of this study was to compare the stiffness characteristics of Taylor Spatial Frame (TSF) fixed with transverse wires and half pins. Design & Methods Experiments were carried out at the biomechanics laboratory at Cardiff University. All mechanical testing was performed with a servo hydraulic test frame (MTS 858 Mini Bionix II(R), MTS Corp., Mineapolis, USA). Custom built mounts were used to attach the bone rigidly to the one end of machine and the TSF ring to the ot...

A multiscale approach to blast neurotrauma modeling:Part II: Methodology for inducing blast injury to in vitro models

Directory of Open Access Journals (Sweden)

Gwen B. Effgen

2012-02-01

Full Text Available Due to the prominent role of improvised explosive devices (IEDs in wounding patterns of U.S. war-fighters in Iraq and Afghanistan, blast injury has risen to a new level of importance and is recognized to be a major cause of injuries to the brain. However, an injury risk-function for microscopic, macroscopic, behavioral, and neurological deficits has yet to be defined. While operational blast injuries can be very complex and thus difficult to analyze, a simplified blast injury model would facilitate studies correlating biological outcomes with blast biomechanics to define tolerance criteria. Blast-induced traumatic brain injury (bTBI results from the translation of a shock wave in air, such as that produced by an IED, into a pressure wave within the skull-brain complex. Our blast injury methodology recapitulates this phenomenon in vitro, allowing for control of the injury biomechanics via a compressed-gas shock tube used in conjunction with a custom-designed, fluid-filled receiver that contains the living culture. The receiver converts the air shock wave into a fast-rising pressure transient with minimal reflections, mimicking the intracranial pressure history in blast. We have developed an organotypic hippocampal slice culture model that exhibits cell death when exposed to a 530  17.7 kPa peak overpressure with a 1.026 ± 0.017 ms duration and 190 ± 10.7 kPa-ms impulse in-air. We have also injured a simplified in vitro model of the blood-brain barrier, which exhibits disrupted integrity immediately following exposure to 581  10.0 kPa peak overpressure with a 1.067 ms ± 0.006 ms duration and 222 ± 6.9 kPa-ms impulse in-air. To better prevent and treat bTBI, both the initiating biomechanics and the ensuing pathobiology must be understood in greater detail. A well-characterized, in vitro model of bTBI, in conjunction with animal models, will be a powerful tool for developing strategies to mitigate the risks of bTBI.

Development of custom measurement system for biomechanical evaluation of independent wheelchair transfers.

Science.gov (United States)

Koontz, Alicia M; Lin, Yen-Sheng; Kankipati, Padmaja; Boninger, Michael L; Cooper, Rory A

2011-01-01

This study describes a new custom measurement system designed to investigate the biomechanics of sitting-pivot wheelchair transfers and assesses the reliability of selected biomechanical variables. Variables assessed include horizontal and vertical reaction forces underneath both hands and three-dimensional trunk, shoulder, and elbow range of motion. We examined the reliability of these measures between 5 consecutive transfer trials for 5 subjects with spinal cord injury and 12 nondisabled subjects while they performed a self-selected sitting pivot transfer from a wheelchair to a level bench. A majority of the biomechanical variables demonstrated moderate to excellent reliability (r > 0.6). The transfer measurement system recorded reliable and valid biomechanical data for future studies of sitting-pivot wheelchair transfers.We recommend a minimum of five transfer trials to obtain a reliable measure of transfer technique for future studies.

Computational biomechanics for medicine from algorithms to models and applications

CERN Document Server

Joldes, Grand; Nielsen, Poul; Doyle, Barry; Miller, Karol

2017-01-01

This volume comprises the latest developments in both fundamental science and patient-specific applications, discussing topics such as: cellular mechanics; injury biomechanics; biomechanics of heart and vascular system; medical image analysis; and both patient-specific fluid dynamics and solid mechanics simulations. With contributions from researchers world-wide, the Computational Biomechanics for Medicine series of titles provides an opportunity for specialists in computational biomechanics to present their latest methodologies and advancements.

Impaired Corneal Biomechanical Properties and the Prevalence of Keratoconus in Mitral Valve Prolapse

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Emine Kalkan Akcay

2014-01-01

Full Text Available Objective. To investigate the biomechanical characteristics of the cornea in patients with mitral valve prolapse (MVP and the prevalence of keratoconus (KC in MVP. Materials and Methods. Fifty-two patients with MVP, 39 patients with KC, and 45 control individuals were recruited in this study. All the participants underwent ophthalmologic examination, corneal analysis with the Sirius system (CSO, and the corneal biomechanical evaluation with Reichert ocular response analyzer (ORA. Results. KC was found in six eyes of four patients (5.7% and suspect KC in eight eyes of five patients (7.7% in the MVP group. KC was found in one eye of one patient (1.1% in the control group (P=0.035. A significant difference occurred in the mean CH and CRF between the MVP and control groups (P=0.006 and P=0.009, resp.. All corneal biomechanical and topographical parameters except IOPcc were significantly different between the KC-MVP groups (P<0.05. Conclusions. KC prevalence is higher than control individuals in MVP patients and the biomechanical properties of the cornea are altered in patients with MVP. These findings should be considered when the MVP patients are evaluated before refractive surgery.

Nano-TiO2/PEEK bioactive composite as a bone substitute material: in vitro and in vivo studies

Science.gov (United States)

Wu, Xiaomian; Liu, Xiaochen; Wei, Jie; Ma, Jian; Deng, Feng; Wei, Shicheng

2012-01-01

Background Compared with titanium (Ti) and other metal implant materials, poly(ether-ether ketone) (PEEK) shows outstanding biomechanical properties. A number of studies have also reported attractive bioactivity for nano-TiO2 (n-TiO2). Methods In this study, n-TiO2/PEEK nanocomposites were prepared, taking advantage of the unique properties of both PEEK polymer and n-TiO2. The in vitro and in vivo bioactivity of these nanocomposites was assessed against a PEEK polymer control. The effect of surface morphology or roughness on the bioactivity of the n-TiO2/PEEK nanocomposites was also studied. n-TiO2/PEEK was successfully fabricated and cut into disks for physical and chemical characterization and in vitro studies, and prepared as cylindrical implants for in vivo studies. Their presence on the surface and dispersion in the composites was observed and analyzed by scanning and transmission electron microscopy and X-ray photoelectron spectroscopy. Results Bioactivity evaluation of the nanocomposites revealed that pseudopods of osteoblasts preferred to anchor at areas where n-TiO2 was present on the surface. In a cell attachment test, smooth PEEK showed the lowest optical density value (0.56 ± 0.07) while rough n-TiO2/PEEK exhibited the highest optical density value (1.21 ± 0.34, P PEEK was approximately twice as large as that of PEEK (P PEEK, especially if it has a rough composite surface. A n-TiO2/PEEK composite with a rough surface could be a novel alternative implant material for orthopedic and dental applications. PMID:22419869

Sixth Computational Biomechanics for Medicine Workshop

CERN Document Server

Nielsen, Poul MF; Miller, Karol; Computational Biomechanics for Medicine : Deformation and Flow

2012-01-01

One of the greatest challenges for mechanical engineers is to extend the success of computational mechanics to fields outside traditional engineering, in particular to biology, biomedical sciences, and medicine. This book is an opportunity for computational biomechanics specialists to present and exchange opinions on the opportunities of applying their techniques to computer-integrated medicine. Computational Biomechanics for Medicine: Deformation and Flow collects the papers from the Sixth Computational Biomechanics for Medicine Workshop held in Toronto in conjunction with the Medical Image Computing and Computer Assisted Intervention conference. The topics covered include: medical image analysis, image-guided surgery, surgical simulation, surgical intervention planning, disease prognosis and diagnostics, injury mechanism analysis, implant and prostheses design, and medical robotics.

Do exercises used in injury prevention programmes modify cutting task biomechanics? A systematic review with meta-analysis.

Science.gov (United States)

Pappas, Evangelos; Nightingale, Elizabeth J; Simic, Milena; Ford, Kevin R; Hewett, Timothy E; Myer, Gregory D

2015-05-01

Some injury prevention programmes aim to reduce the risk of ACL rupture. Although the most common athletic task leading to ACL rupture is cutting, there is currently no consensus on how injury prevention programmes influence cutting task biomechanics. To systematically review and synthesise the scientific literature regarding the influence of injury prevention programme exercises on cutting task biomechanics. The three largest databases (Medline, EMBASE and CINAHL) were searched for studies that investigated the effect of injury prevention programmes on cutting task biomechanics. When possible meta-analyses were performed. Seven studies met the inclusion criteria. Across all studies, a total of 100 participants received exercises that are part of ACL injury prevention programmes and 76 participants served in control groups. Most studies evaluated variables associated with the quadriceps dominance theory. The meta-analysis revealed decreased lateral hamstrings electromyography activity (p ≤ 0.05) while single studies revealed decreased quadriceps and increased medial hamstrings activity and decreased peak knee flexion moment. Findings from single studies reported that ACL injury prevention exercises reduce neuromuscular deficits (knee valgus moment, lateral trunk leaning) associated with the ligament and trunk dominance theories, respectively. The programmes we analysed appear most effective when they emphasise individualised biomechanical technique correction and target postpubertal women. The exercises used in injury prevention programmes have the potential to improve cutting task biomechanics by ameliorating neuromuscular deficits linked to ACL rupture, especially when they emphasise individualised biomechanical technique correction and target postpubertal female athletes. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Advances in Proximal Interphalangeal Joint Arthroplasty: Biomechanics and Biomaterials.

Science.gov (United States)

Zhu, Andy F; Rahgozar, Paymon; Chung, Kevin C

2018-05-01

Proximal interphalangeal (PIP) joint arthritis is a debilitating condition. The complexity of the joint makes management particularly challenging. Treatment of PIP arthritis requires an understanding of the biomechanics of the joint. PIP joint arthroplasty is one treatment option that has evolved over time. Advances in biomaterials have improved and expanded arthroplasty design. This article reviews biomechanics and arthroplasty design of the PIP joint. Copyright © 2018 Elsevier Inc. All rights reserved.

Biomechanics of subcellular structures by non-invasive Brillouin microscopy

Science.gov (United States)

Antonacci, Giuseppe; Braakman, Sietse

2016-11-01

Cellular biomechanics play a pivotal role in the pathophysiology of several diseases. Unfortunately, current methods to measure biomechanical properties are invasive and mostly limited to the surface of a cell. As a result, the mechanical behaviour of subcellular structures and organelles remains poorly characterised. Here, we show three-dimensional biomechanical images of single cells obtained with non-invasive, non-destructive Brillouin microscopy with an unprecedented spatial resolution. Our results quantify the longitudinal elastic modulus of subcellular structures. In particular, we found the nucleoli to be stiffer than both the nuclear envelope (p biomechanics and its role in pathophysiology.

Study in vitro of origin radioprotective food the radioprotective effect in vitro of food borne; Estudio in vitro de radioprotectores de origen alimentario

Energy Technology Data Exchange (ETDEWEB)

Soraino, J. M.; Sebastia, N.; Almonacid, M.; Alonso, O.; Cervera, J.; Such, E.; Silla, M. A.; Villaescusa, J. I.; Montoro, A.

2012-07-01

Study in vitro of origin radioprotective food the radioprotective effect in vitro of food borne substances studied is a first step in developing effective radioprotectors that can prevent radiation damage to healthy tissue., cannot forget that these studies must be accompanied by in vitro studies of toxicity and bioavailability to profile designing radioprotective substance.

Biomechanical in vitro evaluation of three stable internal fixation techniques used in sagittal osteotomy of the mandibular ramus: a study in sheep mandibles

Directory of Open Access Journals (Sweden)

Leandro Benetti de Olivera

2012-08-01

Full Text Available Among the osteotomies performed in orthognathic surgery, the sagittal osteotomy of the mandibular ramus (SOMR is the most common, allowing a great range of movements and stable internal fixation (SIF, therefore eliminating the need of maxillomandibular block in the postoperative period. OBJECTIVES: The purpose of this study was to evaluate the biomechanical resistance of three national systems used for SIF in SOMR in sheep mandibles. MATERIAL AND METHODS: The study was performed in 30 sheep hemi-mandibles randomly divided into 3 experimental groups, each containing 10 hemi-mandibles. The samples were measured to avoid discrepancies and then subjected to SOMR with 5-mm advancement. In group I, 2.0x12 mm screws were used for fixation, inserted in an inverted "L" pattern (inverted "L" group. In group II, fixation was performed with two 2.0x12 mm screws, positioned in a linear pattern and a 4-hole straight miniplate and four 2.0x6.0 mm monocortical screws (hybrid group. In group III, fixation was performed with two 4-hole straight miniplates and eight 2.0x6.0 mm monocortical screws (mini plate group. All materials used for SIF were supplied by Osteosin - SIN. The hemimandibles were subjected to vertical linear load test by Kratos K2000MP mechanical testing unit for loading registration and displacement. RESULTS: All groups showed similar resistance during mechanical test for loading and displacement, with no statistically significant differences between groups according to analysis of variance. CONCLUSION: These results indicate that the three techniques of fixation are equally effective for clinical fixation of SOMR.

Analysis of Biomechanical Factors in Bend Running

OpenAIRE

Bing Zhang; Xinping You; Feng Li

2013-01-01

Sprint running is the demonstration of comprehensive abilities of technology and tactics, under various conditions. However, whether it is just to allocate the tracks for short-distance athletes from different racetracks has been the hot topic. This study analyzes its forces, differences in different tracks and winding influences, in the aspects of sport biomechanics. The results indicate, many disadvantages exist in inner tracks, middle tracks are the best and outer ones are inferior to midd...

Robots in human biomechanics--a study on ankle push-off in walking.

Science.gov (United States)

Renjewski, Daniel; Seyfarth, André

2012-09-01

In biomechanics, explanatory template models are used to identify the basic mechanisms of human locomotion. However, model predictions often lack verification in a realistic environment. We present a method that uses template model mechanics as a blueprint for a bipedal robot and a corresponding computer simulation. The hypotheses derived from template model studies concerning the function of heel-off in walking are analysed and discrepancies between the template model and its real-world anchor are pointed out. Neither extending the ground clearance of the swinging leg nor an impact reduction at touch-down as an effect of heel lifting was supported by the experiments. To confirm the relevance of the experimental findings, a comparison of robot data to human walking data is discussed and we speculate on an alternative explanation of heel-off in human walking, i.e. that the push-off powers the following leg swing.

In vitro metabolism and permeation studies in rat jejunum

DEFF Research Database (Denmark)

Gammelgaard, Bente; Jensen, K; Steffansen, B

1999-01-01

The purpose of these studies was to compare the in vitro absorption of two inorganic chromium(III) compounds: chromium chloride and chromium nitrate, with organic chromium(III)-picolinate; and to investigate if any in vitro metabolism of chromium(VI) takes place. The in vitro metabolism studies...

Biomechanical analysis of the camelid cervical intervertebral disc

Directory of Open Access Journals (Sweden)

Dean K. Stolworthy

2015-01-01

Full Text Available Chronic low back pain (LBP is a prevalent global problem, which is often correlated with degenerative disc disease. The development and use of good, relevant animal models of the spine may improve treatment options for this condition. While no animal model is capable of reproducing the exact biology, anatomy, and biomechanics of the human spine, the quality of a particular animal model increases with the number of shared characteristics that are relevant to the human condition. The purpose of this study was to investigate the camelid (specifically, alpaca and llama cervical spine as a model of the human lumbar spine. Cervical spines were obtained from four alpacas and four llamas and individual segments were used for segmental flexibility/biomechanics and/or morphology/anatomy studies. Qualitative and quantitative data were compared for the alpaca and llama cervical spines, and human lumbar specimens in addition to other published large animal data. Results indicate that a camelid cervical intervertebral disc (IVD closely approximates the human lumbar disc with regard to size, spinal posture, and biomechanical flexibility. Specifically, compared with the human lumbar disc, the alpaca and llama cervical disc size are approximately 62%, 83%, and 75% with regard to area, depth, and width, respectively, and the disc flexibility is approximately 133%, 173%, and 254%, with regard to range of motion (ROM in axial-rotation, flexion-extension, and lateral-bending, respectively. These results, combined with the clinical report of disc degeneration in the llama lower cervical spine, suggest that the camelid cervical spine is potentially well suited for use as an animal model in biomechanical studies of the human lumbar spine.

Bio-mechanical Analysis of Human Joints and Extension of the Study to Robot

OpenAIRE

S. Parasuraman; Ler Shiaw Pei

2008-01-01

In this paper, the bio-mechanical analysis of human joints is carried out and the study is extended to the robot manipulator. This study will first focus on the kinematics of human arm which include the movement of each joint in shoulder, wrist, elbow and finger complexes. Those analyses are then extended to the design of a human robot manipulator. A simulator is built for Direct Kinematics and Inverse Kinematics of human arm. In the simulation of Direct Kinematics, the human joint angles can...

Consequences of biomechanically constrained tasks in the design and interpretation of synergy analyses.

Science.gov (United States)

Steele, Katherine M; Tresch, Matthew C; Perreault, Eric J

2015-04-01

Matrix factorization algorithms are commonly used to analyze muscle activity and provide insight into neuromuscular control. These algorithms identify low-dimensional subspaces, commonly referred to as synergies, which can describe variation in muscle activity during a task. Synergies are often interpreted as reflecting underlying neural control; however, it is unclear how these analyses are influenced by biomechanical and task constraints, which can also lead to low-dimensional patterns of muscle activation. The aim of this study was to evaluate whether commonly used algorithms and experimental methods can accurately identify synergy-based control strategies. This was accomplished by evaluating synergies from five common matrix factorization algorithms using muscle activations calculated from 1) a biomechanically constrained task using a musculoskeletal model and 2) without task constraints using random synergy activations. Algorithm performance was assessed by calculating the similarity between estimated synergies and those imposed during the simulations; similarities ranged from 0 (random chance) to 1 (perfect similarity). Although some of the algorithms could accurately estimate specified synergies without biomechanical or task constraints (similarity >0.7), with these constraints the similarity of estimated synergies decreased significantly (0.3-0.4). The ability of these algorithms to accurately identify synergies was negatively impacted by correlation of synergy activations, which are increased when substantial biomechanical or task constraints are present. Increased variability in synergy activations, which can be captured using robust experimental paradigms that include natural variability in motor activation patterns, improved identification accuracy but did not completely overcome effects of biomechanical and task constraints. These results demonstrate that a biomechanically constrained task can reduce the accuracy of estimated synergies and highlight

Combining epidemiology and biomechanics in sports injury prevention research: a new approach for selecting suitable controls.

Science.gov (United States)

Finch, Caroline F; Ullah, Shahid; McIntosh, Andrew S

2011-01-01

Several important methodological issues need to be considered when designing sports injury case-control studies. Major design goals for case-control studies include the accounting for prior injury risk exposure, and optimal definitions of both cases and suitable controls are needed to ensure this. This article reviews methodological aspects of published sports injury case-control studies, particularly with regard to the selection of controls. It argues for a new approach towards selecting controls for case-control studies that draws on an interface between epidemiological and biomechanical concepts. A review was conducted to identify sport injury case-control studies published in the peer-review literature during 1985-2008. Overall, 32 articles were identified, of which the majority related to upper or lower extremity injuries. Matching considerations were used for control selection in 16 studies. Specific mention of application of biomechanical principles in the selection of appropriate controls was absent from all studies, including those purporting to evaluate the benefits of personal protective equipment to protect against impact injury. This is a problem because it could lead to biased conclusions, as cases and controls are not fully comparable in terms of similar biomechanical impact profiles relating to the injury incident, such as site of the impact on the body. The strength of the conclusions drawn from case-control studies, and the extent to which results can be generalized, is directly influenced by the definition and recruitment of cases and appropriate controls. Future studies should consider the interface between epidemiological and biomechanical concepts when choosing appropriate controls to ensure that proper adjustment of prior exposure to injury risk is made. To provide necessary guidance for the optimal selection of controls in case-control studies of interventions to prevent sports-related impact injury, this review outlines a new case

Biomechanical evaluation of the side-cutting manoeuvre associated with ACL injury in young female handball players

DEFF Research Database (Denmark)

Bencke, Jesper; Curtis, Derek; Krogshede, Christina

2013-01-01

The purpose of the study was to investigate the biomechanics of the knee and hip joint during handball-specific side-cutting on the dominant and non-dominant leg. Understanding the sports-specific biomechanics may improve prevention measures and post-injury treatment....

High-Tensile Strength Tape Versus High-Tensile Strength Suture: A Biomechanical Study.

Science.gov (United States)

Gnandt, Ryan J; Smith, Jennifer L; Nguyen-Ta, Kim; McDonald, Lucas; LeClere, Lance E

2016-02-01

To determine which suture design, high-tensile strength tape or high-tensile strength suture, performed better at securing human tissue across 4 selected suture techniques commonly used in tendinous repair, by comparing the total load at failure measured during a fixed-rate longitudinal single load to failure using a biomechanical testing machine. Matched sets of tendon specimens with bony attachments were dissected from 15 human cadaveric lower extremities in a manner allowing for direct comparison testing. With the use of selected techniques (simple Mason-Allen in the patellar tendon specimens, whip stitch in the quadriceps tendon specimens, and Krackow stitch in the Achilles tendon specimens), 1 sample of each set was sutured with a 2-mm braided, nonabsorbable, high-tensile strength tape and the other with a No. 2 braided, nonabsorbable, high-tensile strength suture. A total of 120 specimens were tested. Each model was loaded to failure at a fixed longitudinal traction rate of 100 mm/min. The maximum load and failure method were recorded. In the whip stitch and the Krackow-stitch models, the high-tensile strength tape had a significantly greater mean load at failure with a difference of 181 N (P = .001) and 94 N (P = .015) respectively. No significant difference was found in the Mason-Allen and simple stitch models. Pull-through remained the most common method of failure at an overall rate of 56.7% (suture = 55%; tape = 58.3%). In biomechanical testing during a single load to failure, high-tensile strength tape performs more favorably than high-tensile strength suture, with a greater mean load to failure, in both the whip- and Krackow-stitch models. Although suture pull-through remains the most common method of failure, high-tensile strength tape requires a significantly greater load to pull-through in a whip-stitch and Krakow-stitch model. The biomechanical data obtained in the current study indicates that high-tensile strength tape may provide better repair

Biomechanical study in vitro on the use of self-designed external fixator in diaphyseal III metacarpal fractures in horses.

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Turek, B; Potyński, A; Wajler, C; Szara, T; Czopowicz, M; Drewnowska, O

2015-01-01

Diaphyseal fractures of the III metacarpal bone represent 22% of all fractures of the long bones in horses. Treatment of such cases is difficult. The most popular solution used in these types of fractures is two plates applied directly to the bone surface, but they are not applicable on contaminated and infected fractures. External fixators are quite commonly used in human medicine, although in veterinary practice there is no typical stabilizer designed for the treatment of diaphyseal fractures of the III metacarpal bone so far. In this study, an external semicircular fixator of our own design was used and in vitro strength tests were conducted to determine the maximum force which would lead to the destruction of non-fractured bone and fractured bone treated with the stabilizer. On the basis of the strength tests, we can conclude that the stabilizer can be strong enough to allow the horse to stand up after surgery. It also has many favorable features which make it easy to assemble and to take care of a wound, while being safe enough for the animal at the same time.

Scleral Biomechanics in the Aging Monkey Eye

Science.gov (United States)

Girard, Michaël J. A.; Suh, J-K. Francis; Bottlang, Michael; Burgoyne, Claude F.; Downs, J. Crawford

2010-01-01

Purpose To investigate the age-related differences in the inhomogeneous, anisotropic, nonlinear biomechanical properties of posterior sclera from old (22.9 ± 5.3 years) and young (1.5 ± 0.7 years) rhesus monkeys. Methods The posterior scleral shell of each eye was mounted on a custom-built pressurization apparatus, then intraocular pressure (IOP) was elevated from 5 to 45 mmHg while the 3D displacements of the scleral surface were measured using speckle interferometry. Each scleral shell geometry was digitally reconstructed from data generated by a 3D digitizer (topography) and 20 MHz ultrasounds (thickness). An inverse finite element (FE) method incorporating a fiber-reinforced constitutive model was used to extract a unique set of biomechanical properties for each eye. Displacements, thickness, stress, strain, tangent modulus, structural stiffness, and preferred collagen fiber orientation were mapped for each posterior sclera. Results The model yielded 3-D deformations of posterior sclera that matched well with those observed experimentally. The posterior sclera exhibited inhomogeneous, anisotropic, nonlinear mechanical behavior. The sclera was significantly thinner (p = 0.038), and tangent modulus and structural stiffness were significantly higher in old monkeys (p biomechanics, and potentially contribute to age-related susceptibility to glaucomatous vision loss. PMID:19494203

Biomechanical model-based displacement estimation in micro-sensor motion capture

International Nuclear Information System (INIS)

Meng, X L; Sun, S Y; Wu, J K; Zhang, Z Q; 3 Building, 21 Heng Mui Keng Terrace (Singapore))" data-affiliation=" (Department of Electrical and Computer Engineering, National University of Singapore (NUS), 02-02-10 I3 Building, 21 Heng Mui Keng Terrace (Singapore))" >Wong, W C

2012-01-01

In micro-sensor motion capture systems, the estimation of the body displacement in the global coordinate system remains a challenge due to lack of external references. This paper proposes a self-contained displacement estimation method based on a human biomechanical model to track the position of walking subjects in the global coordinate system without any additional supporting infrastructures. The proposed approach makes use of the biomechanics of the lower body segments and the assumption that during walking there is always at least one foot in contact with the ground. The ground contact joint is detected based on walking gait characteristics and used as the external references of the human body. The relative positions of the other joints are obtained from hierarchical transformations based on the biomechanical model. Anatomical constraints are proposed to apply to some specific joints of the lower body to further improve the accuracy of the algorithm. Performance of the proposed algorithm is compared with an optical motion capture system. The method is also demonstrated in outdoor and indoor long distance walking scenarios. The experimental results demonstrate clearly that the biomechanical model improves the displacement accuracy within the proposed framework. (paper)

Masticatory biomechanics in the rabbit: a multi-body dynamics analysis.

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Watson, Peter J; Gröning, Flora; Curtis, Neil; Fitton, Laura C; Herrel, Anthony; McCormack, Steven W; Fagan, Michael J

2014-10-06

Multi-body dynamics is a powerful engineering tool which is becoming increasingly popular for the simulation and analysis of skull biomechanics. This paper presents the first application of multi-body dynamics to analyse the biomechanics of the rabbit skull. A model has been constructed through the combination of manual dissection and three-dimensional imaging techniques (magnetic resonance imaging and micro-computed tomography). Individual muscles are represented with multiple layers, thus more accurately modelling muscle fibres with complex lines of action. Model validity was sought through comparing experimentally measured maximum incisor bite forces with those predicted by the model. Simulations of molar biting highlighted the ability of the masticatory system to alter recruitment of two muscle groups, in order to generate shearing or crushing movements. Molar shearing is capable of processing a food bolus in all three orthogonal directions, whereas molar crushing and incisor biting are predominately directed vertically. Simulations also show that the masticatory system is adapted to process foods through several cycles with low muscle activations, presumably in order to prevent rapidly fatiguing fast fibres during repeated chewing cycles. Our study demonstrates the usefulness of a validated multi-body dynamics model for investigating feeding biomechanics in the rabbit, and shows the potential for complementing and eventually reducing in vivo experiments.

Button fixation technique for Achilles tendon reinsertion: a biomechanical study.

Science.gov (United States)

Awogni, David; Chauvette, Guillaume; Lemieux, Marie-Line; Balg, Frédéric; Langelier, Ève; Allard, Jean-Pascal

2014-01-01

Chronic insertional tendinopathy of the Achilles tendon is a frequent and disabling pathologic entity. Operative treatment is indicated for patients for whom nonoperative management has failed. The treatment can consist of the complete detachment of the tendon insertion and extensive debridement. We biomechanically tested a new operative technique that uses buttons for fixation of the Achilles tendon insertion on the posterior calcaneal tuberosity and compared it with 2 standard bone anchor techniques. A total of 40 fresh-frozen cadaver specimens were used to compare 3 fixation techniques for reinserting the Achilles tendon: single row anchors, double row anchors, and buttons. The ultimate loads and failure mechanisms were recorded. The button assembly (median load 764 N, range 713 to 888) yielded a median fixation strength equal to 202% (range 137% to 251%) of that obtained with the double row anchors (median load 412 N, range 301 to 571) and 255% (range 213% to 317%) of that obtained with the single row anchors (median load 338 N, range 241 to 433N). The most common failure mechanisms were suture breakage with the buttons (55%) and pull out of the implant with the double row (70%) and single row (85%) anchors. The results of the present biomechanical cadaver study have shown that Achilles tendon reinsertion fixation using the button technique provides superior pull out strength than the bone anchors tested. Copyright © 2014 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

Lower limb biomechanics in femoroacetabular impingement syndrome: a systematic review and meta-analysis.

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King, Matthew G; Lawrenson, Peter R; Semciw, Adam I; Middleton, Kane J; Crossley, Kay M

2018-05-01

(1) Identify differences in hip and pelvic biomechanics in patients with femoroacetabular impingement syndrome (FAIS) compared with controls during everyday activities (eg, walking, squatting); and (2) evaluate the effects of interventions on hip and pelvic biomechanics during everyday activities. Systematic review. Medline, CINAHL, EMBASE, Scopus and SPORTDiscus until February 2017. Primary aim: studies that investigated hip or pelvic kinematics and/or joint torques of everyday activities in patients with FAIS compared with the asymptomatic contralateral limb or a control group. Secondary aim: studies that evaluated effects of conservative or surgical interventions on patients with FAIS using pre-post or controlled clinical trial designs. Biomechanical data must have been collected using three-dimensional motion capture devices. Reporting quality was assessed using the Epidemiological Appraisal Instrument and data were pooled (standardised mean difference (SMD), 95% CI) where populations and primary outcomes were similar. Fourteen studies were included (11 cross-sectional and three pre/post intervention), varying between low and moderate reporting quality. Patients with FAIS walked with a lower: peak hip extension angle (SMD -0.40, 95% CI -0.71 to -0.09), peak internal rotation angle (-0.67, 95% CI -1.19 to -0.16) and external rotation joint torque (-0.71, 95% CI -1.07 to -0.35), and squatted to a lesser depth with no difference in hip flexion range. Pre/post intervention data were limited in number and quality, and to surgical cohorts. This review suggests that patients with FAIS may demonstrate hip biomechanical impairments during walking and squatting, with minimal literature available to comment on other tasks. The information presented in the review provides insight into the biomechanical differences associated with FAIS; however, the between-group differences were small to moderate. This information may aid in the development of management strategies for

Biomechanics Scholar Citations across Academic Ranks

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Knudson Duane

2015-11-01

Full Text Available Study aim: citations to the publications of a scholar have been used as a measure of the quality or influence of their research record. A world-wide descriptive study of the citations to the publications of biomechanics scholars of various academic ranks was conducted.

Is gender influencing the biomechanical results after autologous chondrocyte implantation?

Science.gov (United States)

Kreuz, Peter C; Müller, Sebastian; Erggelet, Christoph; von Keudell, Arvind; Tischer, Thomas; Kaps, Christian; Niemeyer, Philipp; Hirschmüller, Anja

2014-01-01

The influence of gender on the biomechanical outcome after autologous chondrocyte implantation (ACI) including isokinetic muscle strength measurements has not been investigated. The present prospective study was performed to evaluate gender-specific differences in the biomechanical function 48 months after ACI. Fifty-two patients (mean age 35.6 ± 8.5 years) that met our inclusion criteria, underwent ACI with Bioseed C(®) and were evaluated with the KOOS score preoperatively, 6, 12 and 48 months after surgery. At final follow-up, 44 out of the 52 patients underwent biomechanical evaluation with isokinetic strength measurements of both knees. All data were evaluated separately for men and women and compared for each time interval using the Mann-Whitney U test. Clinical scores improved significantly over the whole study period (p genders. Isokinetic muscle strength measures are significantly worse in women (p role for the explanation of gender-specific results after ACI.

Strength of suture anchor versus transosseous tunnel in anatomic reconstruction of the ankle lateral ligaments: a biomechanical study.

Science.gov (United States)

Li, Hong-Yun; Hua, Ying-Hui; Wu, Zi-Ying; Chen, Bo; Chen, Shi-Yi

2013-11-01

The purpose of this study was to compare the biomechanical characteristics of fixation with 2-suture anchors versus transosseous tunnel fixation in anatomic reconstruction of the ankle lateral ligaments. Six matched pairs of human cadaveric ankles underwent anatomic lateral ankle reconstruction, and fixation of the graft on the talus was achieved with 2 suture anchors or a transosseous tunnel. Ankles for the transosseous tunnel group were chosen at random, with the paired contralateral ankles used for the 2-suture anchor group. Half of the peroneus brevis tendon was harvested as a graft. For each technique, one end of the tendon was secured to the original insertion point of the anterior talofibular ligament (ATFL) at the talus, whereas the other end was armed with 2 No. 5 nonabsorbable sutures (Ethicon, Somerville, NJ) and passed through the bone tunnel in the fibula. Biomechanical testing was performed by applying the force in line with the graft. Load to failure was determined at a displacement rate of 50 mm/min. The load-displacement curve, maximum load at failure (N), and stiffness (N/mm) were recorded and compared between the 2 techniques. There was no difference between constructs in the 2-suture anchor group and the transosseous tunnel group in terms of the ultimate load and stiffness (161.8 ± 47.6 N v 171.9 ± 76.0 N; P = .92; 4.59 ± 1.85 N/mm v 5.77 ± 1.98 N/mm; P = .35). Most constructs failed because of anchor pullout in the 2-suture anchor group (5 of 6) and fracture of the bony bridge in the transosseous tunnel group (6 of 6). The strength of fixation with suture anchors in anatomic reconstruction of the ankle lateral ligaments was equivalent to transosseous tunnel fixation as determined with biomechanical testing. However, this study did not prove that one is advantageous over the other. Both techniques showed excellent biomechanical results. Therefore, the 2-suture anchor fixation approach can be safely used in anatomic reconstruction of the

An Anatomic and Biomechanical Comparison of Bankart Repair Configurations.

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Judson, Christopher H; Voss, Andreas; Obopilwe, Elifho; Dyrna, Felix; Arciero, Robert A; Shea, Kevin P

2017-11-01

Suture anchor repair for anterior shoulder instability can be performed using a number of different repair techniques, but none has been proven superior in terms of anatomic and biomechanical properties. Purpose/Hypothesis: The purpose was to compare the anatomic footprint coverage and biomechanical characteristics of 4 different Bankart repair techniques: (1) single row with simple sutures, (2) single row with horizontal mattress sutures, (3) double row with sutures, and (4) double row with labral tape. The hypotheses were as follows: (1) double-row techniques would improve the footprint coverage and biomechanical properties compared with single-row techniques, (2) horizontal mattress sutures would increase the footprint coverage compared with simple sutures, and (3) repair techniques with labral tape and sutures would not show different biomechanical properties. Controlled laboratory study. Twenty-four fresh-frozen cadaveric specimens were dissected. The native labrum was removed and the footprint marked and measured. Repair for each of the 4 groups was performed, and the uncovered footprint was measured using a 3-dimensional digitizer. The strength of the repair sites was assessed using a servohydraulic testing machine and a digital video system to record load to failure, cyclic displacement, and stiffness. The double-row repair techniques with sutures and labral tape covered 73.4% and 77.0% of the footprint, respectively. These percentages were significantly higher than the footprint coverage achieved by single-row repair techniques using simple sutures (38.1%) and horizontal mattress sutures (32.8%) ( P row and double-row groups or between the simple suture and horizontal mattress suture techniques. Likewise, there was no difference in the biomechanical properties of the double-row repair techniques with sutures versus labral tape. Double-row repair techniques provided better coverage of the native footprint of the labrum but did not provide superior

Comparison of completely knotless and hybrid double-row fixation systems: a biomechanical study.

Science.gov (United States)

Chu, Thomas; McDonald, Erik; Tufaga, Michael; Kandemir, Utku; Buckley, Jenni; Ma, C Benjamin

2011-04-01

The purpose of this study was to compare the biomechanical performance of a completely knotless double-row repair system (SutureCross Knotless Anatomic Fixation System; KFx Medical, Carlsbad, CA) with 2 commonly used hybrid double-row repair (medial knot-tying, lateral knotless) systems (Bio-Corkscrew/PushLock [Arthrex, Naples, FL] and Spiralok/Versalok [DePuy Mitek, Raynham, MA]). Fourteen pairs of fresh-frozen cadaveric shoulders were harvested, the supraspinatus tendons were isolated, and full-thickness supraspinatus tears were created. One of each pair was repaired with the completely knotless system, and the contralateral side was repaired with either of the hybrid systems. The repairs were then subjected to cyclic loading followed by load to failure. Conditioning elongation, peak-to-peak elongation, ultimate load, and mechanism of failure were recorded and compared by use of paired t tests. Seven additional shoulders were tested to determine the effect of refrigeration storage on the completely knotless system by use of the same mechanical testing protocol. For the completely knotless repair group, 11 of 14 paired specimens failed during the cyclic loading period. Only 1 of 14 hybrid repair systems had failures during cyclic loading, and both hybrid repair systems had statistically lower conditioning elongation than the completely knotless repair group. The mean ultimate load of the SutureCross group was 166 ± 87 N, which was significantly lower than that in the Corkscrew/PushLock (310 ± 82 N) and Spiralok/Versalok (337 ± 44 N) groups. There was an effect of refrigeration storage on the peak-to-peak elongation and stiffness of the SutureCross group; however, there was no difference in ultimate tensile load or conditioning elongation. The completely knotless repair system has lower time-zero biomechanical properties than the other 2 hybrid systems. The SutureCross system has lower time-zero biomechanical properties when compared with other hybrid repair

Biomechanical analysis technique choreographic movements (for example, "grand battman jete"

Directory of Open Access Journals (Sweden)

Batieieva N.P.

2015-04-01

Full Text Available Purpose : biomechanical analysis of the execution of choreographic movement "grand battman jete". Material : the study involved students (n = 7 of the department of classical choreography faculty of choreography. Results : biomechanical analysis of choreographic movement "grand battman jete" (classic exercise, obtained kinematic characteristics (path, velocity, acceleration, force of the center of mass (CM bio parts of the body artist (foot, shin, thigh. Built bio kinematic model (phase. The energy characteristics - mechanical work and kinetic energy units legs when performing choreographic movement "grand battman jete". Conclusions : It was found that the ability of an athlete and coach-choreographer analyze the biomechanics of movement has a positive effect on the improvement of choreographic training of qualified athletes in gymnastics (sport, art, figure skating and dance sports.

Lingual biomechanics, case selection and success

Directory of Open Access Journals (Sweden)

Sanjay Labh

2016-01-01

Full Text Available Deeper understanding of lingual biomechanics is prerequisite for success with lingual appliance. The difference between labial and lingual force system must be understood and kept in mind during treatment planning, especially anchorage planning, and extraction decision-making. As point of application of force changes, it completely changes the force system in all planes. This article describes lingual biomechanics, anchorage planning, diagnostic considerations, treatment planning, and case selection criteria in lingual orthodontics.

Biomechanical analysis of double poling in elite cross-country skiers.

Science.gov (United States)

Holmberg, Hans-Christer; Lindinger, Stefan; Stöggl, Thomas; Eitzlmair, Erich; Müller, Erich

2005-05-01

To further the understanding of double poling (DP) through biomechanical analysis of upper and lower body movements during DP in cross-country (XC) skiing at racing speed. Eleven elite XC skiers performed DP at 85% of their maximal DP velocity (V85%) during roller skiing at 1 degrees inclination on a treadmill. Pole and plantar ground reaction forces, joint angles (elbow, hip, knee, and ankle), cycle characteristics, and electromyography (EMG) of upper and lower body muscles were analyzed. 1) Pole force pattern with initial impact force peak and the following active force peak (PPF) correlated to V85%, (r = 0.66, P biomechanical aspects. Future research should further investigate the relationship between biomechanical and physiological variables and elaborate training models to improve DP performance.

Double-row vs single-row rotator cuff repair: a review of the biomechanical evidence.

Science.gov (United States)

Wall, Lindley B; Keener, Jay D; Brophy, Robert H

2009-01-01

A review of the current literature will show a difference between the biomechanical properties of double-row and single-row rotator cuff repairs. Rotator cuff tears commonly necessitate surgical repair; however, the optimal technique for repair continues to be investigated. Recently, double-row repairs have been considered an alternative to single-row repair, allowing a greater coverage area for healing and a possibly stronger repair. We reviewed the literature of all biomechanical studies comparing double-row vs single-row repair techniques. Inclusion criteria included studies using cadaveric, animal, or human models that directly compared double-row vs single-row repair techniques, written in the English language, and published in peer reviewed journals. Identified articles were reviewed to provide a comprehensive conclusion of the biomechanical strength and integrity of the repair techniques. Fifteen studies were identified and reviewed. Nine studies showed a statistically significant advantage to a double-row repair with regards to biomechanical strength, failure, and gap formation. Three studies produced results that did not show any statistical advantage. Five studies that directly compared footprint reconstruction all demonstrated that the double-row repair was superior to a single-row repair in restoring anatomy. The current literature reveals that the biomechanical properties of a double-row rotator cuff repair are superior to a single-row repair. Basic Science Study, SRH = Single vs. Double Row RCR.

Biomechanics of the thorax - research evidence and clinical expertise.

Science.gov (United States)

Lee, Diane Gail

2015-07-01

Understanding the biomechanics of the thorax is critical for understanding its role in multiple conditions since the thorax is part of many integrated systems including the musculoskeletal, respiratory, cardiac, digestive and urogynecological. The thorax is also an integrated system within itself and an element of the whole body/person. Therefore, understanding the biomechanics of the thorax is fundamental to all forms of treatment for multiple conditions. The interpretation of movement examination findings depends on one's view of optimal biomechanics and the influential factors. This article will provide a synopsis of the current state of research evidence as well as observations from clinical experience pertaining to the biomechanics of the thorax in order to help clinicians organise this knowledge and facilitate evidence-based and informed management of the, often complex, patient with or without thoracic pain and impairment. The integrated systems model (ISM) will be introduced as a way to determine when the noted biomechanical findings are relevant to a patient's clinical presentation.

A biomechanical evaluation of proximal femoral nail antirotation with respect to helical blade position in femoral head: A cadaveric study

Directory of Open Access Journals (Sweden)

Jin-Ho Hwang

2012-01-01

Full Text Available Objective: Despite new developments in the management of osteoporotic fractures, complications like screw cutout are still found in the fixation of proximal femur fractures even with biomechanically proven better implants like proximal femoral nail antirotation (PFNA. The purpose of this cadaveric study was to investigate the biomechanical stability of this device in relation to two common positions (center-center and inferior-center of the helical blade in the femoral head in unstable trochanteric fractures. Materials and Methods: Eight pairs of human cadaveric femurs were used; in one group [center-center (C-C group], the helical blade of PFNA was fixed randomly in central position both in anteroposterior and lateral view, whereas in the other group it was fixed in inferior one-third position in anteroposterior and in central position in lateral view [inferior-center (I-C group]. Unstable intertrochanteric fracture was created and each specimen was loaded cyclically till load to failure Results: Angular and rotational displacements were significantly higher within the C-C group compared to the I-C group in both unloaded and loaded condition. Loading to failure was higher in the I-C group compared to the C-C group. No statistical significance was found for this parameter. Correlations between tip apex distance, cyclic loading which lead to femoral head displacement, and ultimate load to failure showed a significant positive relationship. Conclusion: The I-C group was superior to the C-C group and provided better biomechanical stability for angular and rotational displacement. This study would be a stimulus for further experimental studies with larger number specimens and complex loading protocols at multicentres.

Can biomechanical variables predict improvement in crouch gait?

Science.gov (United States)

Hicks, Jennifer L.; Delp, Scott L.; Schwartz, Michael H.

2011-01-01

Many patients respond positively to treatments for crouch gait, yet surgical outcomes are inconsistent and unpredictable. In this study, we developed a multivariable regression model to determine if biomechanical variables and other subject characteristics measured during a physical exam and gait analysis can predict which subjects with crouch gait will demonstrate improved knee kinematics on a follow-up gait analysis. We formulated the model and tested its performance by retrospectively analyzing 353 limbs of subjects who walked with crouch gait. The regression model was able to predict which subjects would demonstrate ‘improved’ and ‘unimproved’ knee kinematics with over 70% accuracy, and was able to explain approximately 49% of the variance in subjects’ change in knee flexion between gait analyses. We found that improvement in stance phase knee flexion was positively associated with three variables that were drawn from knowledge about the biomechanical contributors to crouch gait: i) adequate hamstrings lengths and velocities, possibly achieved via hamstrings lengthening surgery, ii) normal tibial torsion, possibly achieved via tibial derotation osteotomy, and iii) sufficient muscle strength. PMID:21616666

Emulating facial biomechanics using multivariate partial least squares surrogate models

OpenAIRE

Martens, Harald; Wu, Tim; Hunter, Peter; Mithraratne, Kumar

2014-01-01

This is the author’s final, accepted and refereed manuscript to the article. Locked until 2015-05-06 A detailed biomechanical model of the human face driven by a network of muscles is a useful tool in relating the muscle activities to facial deformations. However, lengthy computational times often hinder its applications in practical settings. The objective of this study is to replace precise but computationally demanding biomechanical model by a much faster multivariate meta-mode...

The biomechanics study of rabbit osteoporosis models treated by 99Tcm-MDP combined with GuKangLing

International Nuclear Information System (INIS)

Gao Kejia; Zhao Guoding; Ye Zhiwei; Mei Xiaogang; Tian Yingmin; Yan Chushun; Wang Wei; Li Wei; Cai Zhengyu; Song Haiping

2011-01-01

Objective: To study the bone biomechanics of the rabbit osteoporosis models induced by dexamethasone sodium phosphate injection (DX) using a combined treatment modality of 99 Tc-MDP and GuKangLing. Methods: Rabbits were intramuscularly injected with DX (2 mg/kg) twice a week for 6 weeks. The animal osteoporosis model group (Group C) and normal group (Group A) were compared to confirm the model was available. Another control group (Group B), the osteoporosis control group (Group D) were set for the comparison at the end of the experiment. The 99 Tc-MDP therapy group (Group E), GuKangLing therapy group (Group F) and 99 Tc-MDP plus GuKangLing therapy group (Group G) were included in the study. The treatment lasted for 16 weeks. The bone biomechanics, cytopathology bone histomorphology, bone mineral density (BMD), X-ray, CT, bone scintigraphy and serum bone alkaline phosphatase (BALP) and P (bone gla protein) were chosen as the markers or methods to evaluate the treatment results (excellent, effective and invalid). The analysis of variance (ANOVA) and t-test were used for group comparison analysis. Results: Cytopathology result indicated that there was no bone trabecular destruction in Group A. However, there was distinct bone destruction in Group C. The bone biomechanics (left femur head (265.914 ±52.773) N, L 4 (369.671 ±94.919) N), BMD (left femur (0.238 ±0.016) g/cm 2 , L 4 (0.236 ±0.016) g/cm 2 ) and bone histomorphology ((66.230 ± 10.848)%) in Group C reduced clearly as compared with Group A ((405.343±55.410) N, (750.870±53.718) N, (0.294±0.017) g/cm 2 , (0.302±0.023) g/cm 2 , (131.500 ± 21.846)%) (t ≥4.550, all P<0.01). Radionuclide bone scan also showed that the uptake of tracers was higher by the main arthrosis in Group C than that in Group A. Vertebra was not clearly visualized on bone scan image. There were significant differences between Group A and Group C in serum BALP and P ((45.000±7.303) vs (12.485 ±1.512) U/L, (0.168±0.018) vs (0.115 �

Biomechanically determined hand force limits protecting the low back during occupational pushing and pulling tasks.

Science.gov (United States)

Weston, Eric B; Aurand, Alexander; Dufour, Jonathan S; Knapik, Gregory G; Marras, William S

2018-06-01

Though biomechanically determined guidelines exist for lifting, existing recommendations for pushing and pulling were developed using a psychophysical approach. The current study aimed to establish objective hand force limits based on the results of a biomechanical assessment of the forces on the lumbar spine during occupational pushing and pulling activities. Sixty-two subjects performed pushing and pulling tasks in a laboratory setting. An electromyography-assisted biomechanical model estimated spinal loads, while hand force and turning torque were measured via hand transducers. Mixed modelling techniques correlated spinal load with hand force or torque throughout a wide range of exposures in order to develop biomechanically determined hand force and torque limits. Exertion type, exertion direction, handle height and their interactions significantly influenced dependent measures of spinal load, hand force and turning torque. The biomechanically determined guidelines presented herein are up to 30% lower than comparable psychophysically derived limits and particularly more protective for straight pushing. Practitioner Summary: This study utilises a biomechanical model to develop objective biomechanically determined push/pull risk limits assessed via hand forces and turning torque. These limits can be up to 30% lower than existing psychophysically determined pushing and pulling recommendations. Practitioners should consider implementing these guidelines in both risk assessment and workplace design moving forward.

Biopolymer augmentation of the lag screw in the treatment of femoral neck fractures - a biomechanical in-vitro study

Directory of Open Access Journals (Sweden)

Paech A

2010-04-01

Full Text Available Abstract The cut-out of the sliding screw is one of the most common complications in the treatment of intertrochanteric fractures. The reasons for the cut-out are: a suboptimal position of the hip-screw in the femoral head, the type of fracture and poor bone quality. The aim of this study was to reproduce the cut-out event biomechanically and to evaluate the possible prevention of this event by the use of a biopolymer augmentation of the hip screw. Concerning the density and compression force of osteoporotic femoral bone polyurethane foam according to the terms of the Association for Standard Testing Material (ASTMF 1839-97 was used as test material. The polyurethane foam Lumoltan 200 with a compression force of 3.3 Mpa and a density of 0.192 g/cm3 was used to reproduce the osteoporotic bone of the femoral fragment (density 12 lbm/ft3. A cylinder of 50 mm of length and 50 mm of width was produced by a rotary splint raising procedure with planar contact. The axial load of the system was performed by a hydraulic force cylinder of a universal test machine type Zwick 1455, Ulm, Germany. The CCD-angle of the used TGN-System was preset at 130 degrees. The migration pattern of the hip screw in the polyurethane foam was measured and expressed as a curve of the distance in millimeter [mm] against the applied load in Newton [N] up to the cut-out point. During the tests the implants reached a critical changing point from stable to unstable with an increased load progression of steps of 50 Newton. This unstable point was characterized by an increased migration speed in millimeters and higher descending gradient in the migration curve. This peak of the migration curve served as an indicator for the change of the hip screw position in the simulated bone material. The applied load in the non-augmented implant showed that in this group for a density degree of 12 (0,192 g/cm3 the mean force at the failure point was 1431 Newton (± 52 Newton. In the augmented

Engineering a 3D-Bioprinted Model of Human Heart Valve Disease Using Nanoindentation-Based Biomechanics

Directory of Open Access Journals (Sweden)

Dewy C. van der Valk

2018-05-01

Full Text Available In calcific aortic valve disease (CAVD, microcalcifications originating from nanoscale calcifying vesicles disrupt the aortic valve (AV leaflets, which consist of three (biomechanically distinct layers: the fibrosa, spongiosa, and ventricularis. CAVD has no pharmacotherapy and lacks in vitro models as a result of complex valvular biomechanical features surrounding resident mechanosensitive valvular interstitial cells (VICs. We measured layer-specific mechanical properties of the human AV and engineered a three-dimensional (3D-bioprinted CAVD model that recapitulates leaflet layer biomechanics for the first time. Human AV leaflet layers were separated by microdissection, and nanoindentation determined layer-specific Young’s moduli. Methacrylated gelatin (GelMA/methacrylated hyaluronic acid (HAMA hydrogels were tuned to duplicate layer-specific mechanical characteristics, followed by 3D-printing with encapsulated human VICs. Hydrogels were exposed to osteogenic media (OM to induce microcalcification, and VIC pathogenesis was assessed by near infrared or immunofluorescence microscopy. Median Young’s moduli of the AV layers were 37.1, 15.4, and 26.9 kPa (fibrosa/spongiosa/ventricularis, respectively. The fibrosa and spongiosa Young’s moduli matched the 3D 5% GelMa/1% HAMA UV-crosslinked hydrogels. OM stimulation of VIC-laden bioprinted hydrogels induced microcalcification without apoptosis. We report the first layer-specific measurements of human AV moduli and a novel 3D-bioprinted CAVD model that potentiates microcalcification by mimicking the native AV mechanical environment. This work sheds light on valvular mechanobiology and could facilitate high-throughput drug-screening in CAVD.

Biomechanics of the pelvic floor musculature

NARCIS (Netherlands)

Janda, S.

2006-01-01

The present thesis was motivated by two main goals. The first research goal of the thesis was to understand the complex biomechanical behaviour of the pelvic floor muscles. The second goal was to study the mechanism of the pelvic organ prolapse (genital prolapse). The pelvic floor in humans is a

Two-Segment Foot Model for the Biomechanical Analysis of Squat

OpenAIRE

Panero, E.; Gastaldi, L.; Rapp, W.

2017-01-01

Squat exercise is acquiring interest in many fields, due to its benefits in improving health and its biomechanical similarities to a wide range of sport motions and the recruitment of many body segments in a single maneuver. Several researches had examined considerable biomechanical aspects of lower limbs during squat, but not without limitations. The main goal of this study focuses on the analysis of the foot contribution during a partial body weight squat, using a two-segment foot model tha...

A Comparative Biomechanical Analysis of 2 Double-Row, Distal Triceps Tendon Repairs

OpenAIRE

Dorweiler, Matthew A.; Van Dyke, Rufus O.; Siska, Robert C.; Boin, Michael A.; DiPaola, Mathew J.

2017-01-01

Background: Triceps tendon ruptures are rare orthopaedic injuries that almost always require surgical repair. This study tests the biomechanical properties of an original anchorless double-row triceps repair against a previously reported knotless double-row repair. Hypothesis: The anchorless double-row triceps repair technique will yield similar biomechanical properties when compared with the knotless double-row repair technique. Study Design: Controlled laboratory study. Methods: Eighteen ca...

Biomechanics of footwear.

Science.gov (United States)

Snijders, C J

1987-07-01

This article discusses biomechanical principles that indicate a number of basic design criteria for shoes and the properties of good footwear in terms of normal daily activities at home, at school, and at work. These properties also apply to normal occupational footwear and safety footwear.

Prospective Study of the Relation between Landing Biomechanics and Jumper's Knee

NARCIS (Netherlands)

der Worp, H van; van der Does, H T D; Brink, M.S.; Zwerver, J.; Hijmans, J.M.

The literature on the relation between jump biomechanics and jumper's knee indicates that a jump with horizontal displacement poses a threat for developing jumper's knee. Subjects with jumper's knee have been shown to display a stiff landing pattern characterized by a small range of motion. However,

Research and Teaching: Assessing the Effect of Problem-Based Learning on Undergraduate Student Learning in Biomechanics

Science.gov (United States)

Mandeville, David; Stoner, Mark

2015-01-01

The aim of this study was to assess the effect of using the problem-based learning (PBL) teaching strategy on student academic achievement and secondary learning outcomes when compared with the traditional lecture (TL) for an undergraduate Biomechanics course. Successive undergraduate Biomechanics courses--a TL cohort and a PBL cohort--were…

Soft Tissue Biomechanical Modeling for Computer Assisted Surgery

CERN Document Server

2012-01-01

  This volume focuses on the biomechanical modeling of biological tissues in the context of Computer Assisted Surgery (CAS). More specifically, deformable soft tissues are addressed since they are the subject of the most recent developments in this field. The pioneering works on this CAS topic date from the 1980's, with applications in orthopaedics and biomechanical models of bones. More recently, however, biomechanical models of soft tissues have been proposed since most of the human body is made of soft organs that can be deformed by the surgical gesture. Such models are much more complicated to handle since the tissues can be subject to large deformations (non-linear geometrical framework) as well as complex stress/strain relationships (non-linear mechanical framework). Part 1 of the volume presents biomechanical models that have been developed in a CAS context and used during surgery. This is particularly new since most of the soft tissues models already proposed concern Computer Assisted Planning, with ...

Biomechanical interpretation of a free-breathing lung motion model

International Nuclear Information System (INIS)

Zhao Tianyu; White, Benjamin; Lamb, James; Low, Daniel A; Moore, Kevin L; Yang Deshan; Mutic, Sasa; Lu Wei

2011-01-01

The purpose of this paper is to develop a biomechanical model for free-breathing motion and compare it to a published heuristic five-dimensional (5D) free-breathing lung motion model. An ab initio biomechanical model was developed to describe the motion of lung tissue during free breathing by analyzing the stress–strain relationship inside lung tissue. The first-order approximation of the biomechanical model was equivalent to a heuristic 5D free-breathing lung motion model proposed by Low et al in 2005 (Int. J. Radiat. Oncol. Biol. Phys. 63 921–9), in which the motion was broken down to a linear expansion component and a hysteresis component. To test the biomechanical model, parameters that characterize expansion, hysteresis and angles between the two motion components were reported independently and compared between two models. The biomechanical model agreed well with the heuristic model within 5.5% in the left lungs and 1.5% in the right lungs for patients without lung cancer. The biomechanical model predicted that a histogram of angles between the two motion components should have two peaks at 39.8° and 140.2° in the left lungs and 37.1° and 142.9° in the right lungs. The data from the 5D model verified the existence of those peaks at 41.2° and 148.2° in the left lungs and 40.1° and 140° in the right lungs for patients without lung cancer. Similar results were also observed for the patients with lung cancer, but with greater discrepancies. The maximum-likelihood estimation of hysteresis magnitude was reported to be 2.6 mm for the lung cancer patients. The first-order approximation of the biomechanical model fit the heuristic 5D model very well. The biomechanical model provided new insights into breathing motion with specific focus on motion trajectory hysteresis.

Biomechanical considerations in mandibular incisor extraction cases.

Science.gov (United States)

Rachala, Madhukar Reddy; Aileni, Kaladhar Reddy; Dasari, Arun Kumar; Sinojiya, Jay

2015-01-01

Mandibular incisor extraction can be regarded as a valuable treatment option in certain malocclusions to obtain excellence in orthodontic results in terms of function, aesthetics and stability. This treatment alternative is indicated in clinical situations like mild to moderate class III malocclusion, mild anterior mandibular tooth size excess, periodontally compromised teeth, ectopic eruption of mandibular incisor and minimal openbite tendencies. Unlike in premolar extraction cases, space closure in mandibular incisor extraction cases is unique in which the extraction space will be in the middle of the arch. The end result of space closure in these cases should be well aligned, upright, anterior teeth with parallel roots and the goal can be achieved with the bodily tooth movement through proper application of biomechanics. The purpose of this article is to explain the biomechanics of space closure in mandibular incisor extraction cases.

The effect of pharmacological treatment on gait biomechanics in peripheral arterial disease patients

Science.gov (United States)

2010-01-01

Background Pharmacological treatment has been advocated as a first line therapy for Peripheral Arterial Disease (PAD) patients suffering from intermittent claudication. Previous studies document the ability of pharmacological treatment to increase walking distances. However, the effect of pharmacological treatment on gait biomechanics in PAD patients has not been objectively evaluated as is common with other gait abnormalities. Methods Sixteen patients were prescribed an FDA approved drug (Pentoxifylline or Cilostazol) for the treatment of symptomatic PAD. Patients underwent baseline gait testing prior to medication use which consisted of acquisition of ground reaction forces and kinematics while walking in a pain free state. After three months of treatment, patients underwent repeat gait testing. Results Patients with symptomatic PAD had significant gait abnormalities at baseline during pain free walking as compared to healthy controls. However, pharmacological treatment did not produce any identifiable alterations on the biomechanics of gait of the PAD patients as revealed by the statistical comparisons performed between pre and post-treatment and between post-treatment and the healthy controls. Conclusions Pharmacological treatment did not result in statistically significant improvements in the gait biomechanics of patients with symptomatic PAD. Future studies will need to further explore different cohorts of patients that have shown to improve significantly their claudication distances and/or their muscle fiber morphology with the use of pharmacological treatment and determine if this is associated with an improvement in gait biomechanics. Using these methods we may distinguish the patients who benefit from pharmacotherapy and those who do not. PMID:20529284

Elastin density: Link between histological and biomechanical properties of vaginal tissue in women with pelvic organ prolapse?

Science.gov (United States)

de Landsheere, Laurent; Brieu, Mathias; Blacher, Silvia; Munaut, Carine; Nusgens, Betty; Rubod, Chrystèle; Noel, Agnès; Foidart, Jean-Michel; Nisolle, Michelle; Cosson, Michel

2016-04-01

The aim of the study was to correlate histological and biomechanical characteristics of the vaginal wall in women with pelvic organ prolapse (POP). Tissue samples were collected from the anterior [point Ba; POP Questionnaire (POP-Q)] and/or posterior (point Bp; POP-Q) vaginal wall of 15 women who underwent vaginal surgery for POP. Both histological and biomechanical assessments were performed from the same tissue samples in 14 of 15 patients. For histological assessment, the density of collagen and elastin fibers was determined by combining high-resolution virtual imaging and computer-assisted digital image analysis. For biomechanical testing, uniaxial tension tests were performed to evaluate vaginal tissue stiffness at low (C0) and high (C1) deformation rates. Biomechanical testing highlights the hyperelastic behavior of the vaginal wall. At low strains (C0), vaginal tissue appeared stiffer when elastin density was low. We found a statistically significant inverse relationship between C0 and the elastin/collagen ratio (p = 0.048) in the lamina propria. However, at large strain levels (C1), no clear relationship was observed between elastin density or elastin/collagen ratio and stiffness, likely reflecting the large dispersion of the mechanical behavior of the tissue samples. Histological and biomechanical properties of the vaginal wall vary from patient to patient. This study suggests that elastin density deserves consideration as a relevant factor of vaginal stiffness in women with POP.

Effect of material property heterogeneity on biomechanical modeling of prostate under deformation

International Nuclear Information System (INIS)

Samavati, Navid; McGrath, Deirdre M; Ménard, Cynthia; Jewett, Michael A S; Van der Kwast, Theo; Brock, Kristy K

2015-01-01

Biomechanical model based deformable image registration has been widely used to account for prostate deformation in various medical imaging procedures. Biomechanical material properties are important components of a biomechanical model. In this study, the effect of incorporating tumor-specific material properties in the prostate biomechanical model was investigated to provide insight into the potential impact of material heterogeneity on the prostate deformation calculations. First, a simple spherical prostate and tumor model was used to analytically describe the deformations and demonstrate the fundamental effect of changes in the tumor volume and stiffness in the modeled deformation. Next, using a clinical prostate model, a parametric approach was used to describe the variations in the heterogeneous prostate model by changing tumor volume, stiffness, and location, to show the differences in the modeled deformation between heterogeneous and homogeneous prostate models. Finally, five clinical prostatectomy examples were used in separately performed homogeneous and heterogeneous biomechanical model based registrations to describe the deformations between 3D reconstructed histopathology images and ex vivo magnetic resonance imaging, and examine the potential clinical impact of modeling biomechanical heterogeneity of the prostate. The analytical formulation showed that increasing the tumor volume and stiffness could significantly increase the impact of the heterogeneous prostate model in the calculated displacement differences compared to the homogeneous model. The parametric approach using a single prostate model indicated up to 4.8 mm of displacement difference at the tumor boundary compared to a homogeneous model. Such differences in the deformation of the prostate could be potentially clinically significant given the voxel size of the ex vivo MR images (0.3  ×  0.3  ×  0.3 mm). However, no significant changes in the registration accuracy were

Biomedical Imaging and Computational Modeling in Biomechanics

CERN Document Server

Iacoviello, Daniela

2013-01-01

This book collects the state-of-art and new trends in image analysis and biomechanics. It covers a wide field of scientific and cultural topics, ranging from remodeling of bone tissue under the mechanical stimulus up to optimizing the performance of sports equipment, through the patient-specific modeling in orthopedics, microtomography and its application in oral and implant research, computational modeling in the field of hip prostheses, image based model development and analysis of the human knee joint, kinematics of the hip joint, micro-scale analysis of compositional and mechanical properties of dentin, automated techniques for cervical cell image analysis, and iomedical imaging and computational modeling in cardiovascular disease.   The book will be of interest to researchers, Ph.D students, and graduate students with multidisciplinary interests related to image analysis and understanding, medical imaging, biomechanics, simulation and modeling, experimental analysis.

Biomechanical evaluation of native acromioclavicular joint ligaments and two reconstruction techniques in the presence of the sternoclavicular joint: A cadaver study.

Science.gov (United States)

Masionis, Povilas; Šatkauskas, Igoris; Mikelevičius, Vytautas; Ryliškis, Sigitas; Bučinskas, Vytautas; Griškevičius, Julius; Martin Oliva, Xavier; Monzó Planella, Mariano; Porvaneckas, Narūnas; Uvarovas, Valentinas

2017-01-01

Where is over 100 reconstruction techniques described for acromioclavicular (AC) joint reconstruction. Although, it is not clear whether the presence of the sternoclavicular (SC) joint influences the biomechanical properties of native AC ligaments and reconstruction techniques. The purpose of the present study was to investigate the biomechanical properties of native AC joint ligaments and two reconstruction techniques in cadavers with the SC joint still present. We tested eight fresh-frozen cadaver hemithoraces for superior translation (70 N load) and translation increment after 1000 cycles (loading from 20 to 70 N) in a controlled laboratory study. There were three testing groups created: native ligaments, the single coracoclavicular loop (SCL) technique, and the two coracoclavicular loops (TCL) technique. Superior translation was measured after static loading. Translation increment was calculated as the difference between superior translation after cyclic and static loading. Native AC ligaments showed significantly lower translation than the SCL ( p = 0.023) and TCL ( p = 0.046) groups. The SCL had a significantly lower translation increment than native AC ligaments ( p = 0.028). There was no significant difference between reconstruction techniques in terms of translation ( p = 0.865) and translation increment ( p = 0.113). Native AC joint ligaments had better static properties than both reconstruction techniques and worse dynamic biomechanical properties than the SCL technique. The SCL technique appeared to be more secure than the TCL technique. The presence of the SC joint did not have an observable influence on test results.

Scale-Independent Biomechanical Optimization

National Research Council Canada - National Science Library

Schutte, J. F; Koh, B; Reinbolt, J. A; Haftka, R. T; George, A; Fregly, B. J

2003-01-01

...: the Particle Swarm Optimizer (PSO). They apply this method to the biomechanical system identification problem of finding positions and orientations of joint axes in body segments through the processing of experimental movement data...

Clinical, biomechanical and morphological assessment of anterior cruciate ligament Kevlar®-based artificial prosthesis in rabbit model.

Science.gov (United States)

de la Garza-Castro, Santiago; González-Rivera, Carlos E; Vílchez-Cavazos, Félix; Morales-Avalos, Rodolfo; Barrera-Flores, Francisco J; Elizondo-Omaña, Rodrigo E; Soto-Dominguez, Adolfo; Acosta-Olivo, Carlos; Mendoza-Lemus, Oscar F

2017-07-27

The aim of this study was to evaluate the clinical, biomechanical and morphological characteristics of a Kevlar®-based prosthetic ligament as a synthetic graft of the anterior cruciate ligament (ACL) in an experimental animal model in rabbits. A total of 27 knees of rabbits randomly divided into 3 groups (control, ACL excision and ACL replacement with a Kevlar® prosthesis) were analyzed using clinical, biomechanical and morphological tests at 6, 12 and 18 weeks postprocedure. The mean displacement in mechanical testing was 0.73 ± 0.06 mm, 1.58 ± 0.19 mm and 0.94 ± 0.20 mm for the control, ACL excision and ACL replacement with synthetic prosthesis groups, respectively. The results showed an improvement in the stability of the knee with the use of the Kevlar® synthetic prosthesis in the biomechanical testing (p0.05), between the replacement group and the control group. The histological study revealed a good morphological adaptation of the synthetic material to the knee. This study proposes a new animal model for the placement and evaluation of Kevlar®-based synthetic ACL implants. The studied prosthesis showed promising behavior in the clinical and biomechanical tests and in the histological analysis. This study lays the foundation for further basic and clinical studies of artificial ACL prostheses using this material.

The Effect of Pterygium and Pterygium Surgery on Corneal Biomechanics.

Science.gov (United States)

Koç, Mustafa; Yavrum, Fuat; Uzel, Mehmet Murat; Aydemir, Emre; Özülken, Kemal; Yılmazbaş, Pelin

2018-01-01

To evaluate the effect of pterygium and pterygium surgery on corneal biomechanics by ocular response analyzer (ORA, Reichert, USA). This study considered 68 eyes (from 34 patients with a mean age of 21.2±7.1 years) with unilateral nasal, primary pterygium (horizontal length biomechanics. The correlation of the ORA measurements with the pterygium area was evaluated. Mean pterygium horizontal length and area were 3.31±1.43 mm and 6.82±2.17 mm 2 , respectively. There was no statistically significant difference between the eyes with and without pterygium in corneal hysteresis (CH, p=0.442), corneal resistance factor (CRF, p=0.554), corneal-compensated intraocular pressure (IOP cc , p=0.906), and Goldmann-correlated IOP (IOP g , p=0.836). All preoperative parameters decreased after surgery; however, none of them were statistically significant (CH, p=0.688; CRF, p=0.197; IOP cc , p=0.503; IOP g , p=0.231). There were no correlations between pterygium area and ORA measurements (p>0.05). Pterygium biomechanics. These results may be taken into account when cornea biomechanics, mainly intraocular pressure measurements, are important.

Assessment of corneal biomechanical parameters in myopes and emmetropes using the Corvis ST.

Science.gov (United States)

Lee, Rachel; Chang, Robert T; Wong, Ian Y H; Lai, Jimmy S M; Lee, Jacky W Y; Singh, Kuldev

2016-03-01

Prior studies have demonstrated conflicting results regarding the relationship between corneal biomechanical properties and refractive error. Thus, the purpose of this study was to compare the corneal biomechanical parameters of myopes and emmetropes. Ninety-four subjects with varying degrees of myopia (aged 29 to 74 years, spherical equivalent [SE] -0.5 to -17.5 D) and 25 emmetropes (aged 19 to 75 years, SE: -0.5 to +0.5 D) presenting at the Queen Mary Hospital, Hong Kong were recruited sequentially for this prospective study. All patients were phakic with no history of coexisting ocular disease. The corneal biomechanical parameters of the right eye of each subject were analysed using the Corvis ST non-contact tonometer. Intraocular pressure (IOP) was measured using both the Corvis ST and the Topcon Non-Contact Tonometer CT-80. Refractive error was measured by non-cycloplegic subjective and objective refractometry. High myopes (SE greater than -6.00 D) demonstrated greater mean outward applanation velocities (p < 0.001) and peak distance measurements (p = 0.009) compared to both low to moderate myopes (SE -0.50 to -6.00 D) and emmetropes. Both outward applanation velocity and peak distance were moderately correlated with refractive error (p ≤ 0.001), strongly correlated with IOP and weakly correlated with central corneal thickness. There were no statistically significant differences in age, IOP or central corneal thickness among emmetropes, low to moderate myopes or high myopes. Within this study of Chinese subjects, high myopes demonstrate greater corneal mean outward applanation velocity on Corvis ST testing, than emmetropes. In particular, those with high myopia (SE greater than -6.00 D) show a distinct corneal biomechanical profile relative to those with either emmetropia or low to moderate myopia using the Corvis ST. © 2016 Optometry Australia.

Biomechanics of the brain

CERN Document Server

Miller, Karol

2011-01-01

With contributions from scientists at major institutions, this book presents an introduction to brain anatomy for engineers and scientists. It provides, for the first time, a comprehensive resource in the field of brain biomechanics.

Biomechanical comparison of transoral and transbuccal lateral ...

African Journals Online (AJOL)

Objectives: The purpose of this experimental study was to compare the biomechanical behaviors of two different types of osteosynthesis that are used in the treatment of mandibular angle fractures. Materials and Methods: Twenty synthetic polyurethane human mandible replicas, with medullar and cortical portions, were ...

Matrix Metalloproteinase 9 (MMP-9 Regulates Vein Wall Biomechanics in Murine Thrombus Resolution.

Directory of Open Access Journals (Sweden)

Khanh P Nguyen

Full Text Available Deep venous thrombosis is a common vascular problem with long-term complications including post-thrombotic syndrome. Post-thrombotic syndrome consists of leg pain, swelling and ulceration that is related to incomplete or maladaptive resolution of the venous thrombus as well as loss of compliance of the vein wall. We examine the role of metalloproteinase-9 (MMP-9, a gene important in extracellular remodeling in other vascular diseases, in mediating thrombus resolution and biomechanical changes of the vein wall.The effects of targeted deletion of MMP-9 were studied in an in vivo murine model of thrombus resolution using the FVB strain of mice. MMP-9 expression and activity significantly increased on day 3 after DVT. The lack of MMP-9 impaired thrombus resolution by 27% and this phenotype was rescued by the transplantation of wildtype bone marrow cells. Using novel biomechanical techniques, we demonstrated that the lack of MMP-9 significantly decreased thrombus-induced loss of vein wall compliance. Biomechanical analysis of the contribution of individual structural components showed that MMP-9 affected the elasticity of the extracellular matrix and collagen-elastin fibers. Biochemical and histological analyses correlated with these biomechanical effects as thrombi of mice lacking MMP-9 had significantly fewer macrophages and collagen as compared to those of wildtype mice.MMP-9 mediates thrombus-induced loss of vein wall compliance by increasing stiffness of the extracellular matrix and collagen-elastin fibers during thrombus resolution. MMP-9 also mediates macrophage and collagen content of the resolving thrombus and bone-marrow derived MMP-9 plays a role in resolution of thrombus mass. These disparate effects of MMP-9 on various aspects of thrombus illustrate the complexity of individual protease function on biomechanical and morphometric aspects of thrombus resolution.

Matrix Metalloproteinase 9 (MMP-9) Regulates Vein Wall Biomechanics in Murine Thrombus Resolution

Science.gov (United States)

Nguyen, Khanh P.; McGilvray, Kirk C.; Puttlitz, Christian M.; Mukhopadhyay, Subhradip; Chabasse, Christine; Sarkar, Rajabrata

2015-01-01

Objective Deep venous thrombosis is a common vascular problem with long-term complications including post-thrombotic syndrome. Post-thrombotic syndrome consists of leg pain, swelling and ulceration that is related to incomplete or maladaptive resolution of the venous thrombus as well as loss of compliance of the vein wall. We examine the role of metalloproteinase-9 (MMP-9), a gene important in extracellular remodeling in other vascular diseases, in mediating thrombus resolution and biomechanical changes of the vein wall. Methods and Results The effects of targeted deletion of MMP-9 were studied in an in vivo murine model of thrombus resolution using the FVB strain of mice. MMP-9 expression and activity significantly increased on day 3 after DVT. The lack of MMP-9 impaired thrombus resolution by 27% and this phenotype was rescued by the transplantation of wildtype bone marrow cells. Using novel biomechanical techniques, we demonstrated that the lack of MMP-9 significantly decreased thrombus-induced loss of vein wall compliance. Biomechanical analysis of the contribution of individual structural components showed that MMP-9 affected the elasticity of the extracellular matrix and collagen-elastin fibers. Biochemical and histological analyses correlated with these biomechanical effects as thrombi of mice lacking MMP-9 had significantly fewer macrophages and collagen as compared to those of wildtype mice. Conclusions MMP-9 mediates thrombus-induced loss of vein wall compliance by increasing stiffness of the extracellular matrix and collagen-elastin fibers during thrombus resolution. MMP-9 also mediates macrophage and collagen content of the resolving thrombus and bone-marrow derived MMP-9 plays a role in resolution of thrombus mass. These disparate effects of MMP-9 on various aspects of thrombus illustrate the complexity of individual protease function on biomechanical and morphometric aspects of thrombus resolution. PMID:26406902

Biomechanical and nonfunctional assessment of physical capacity in male ICU survivors

DEFF Research Database (Denmark)

Poulsen, Jesper Brøndum; Rose, Martin Høyer; Jensen, Bente Rona

2013-01-01

: ICU admission is associated with decreased physical function for years after discharge. The underlying mechanisms responsible for this muscle function impairment are undescribed. The aim of this study was to describe the biomechanical properties of the quadriceps muscle in ICU survivors 12 months...

Phase reversal of biomechanical functions and muscle activity in backward pedaling.

Science.gov (United States)

Ting, L H; Kautz, S A; Brown, D A; Zajac, F E

1999-02-01

Computer simulations of pedaling have shown that a wide range of pedaling tasks can be performed if each limb has the capability of executing six biomechanical functions, which are arranged into three pairs of alternating antagonistic functions. An Ext/Flex pair accelerates the limb into extension or flexion, a Plant/Dorsi pair accelerates the foot into plantarflexion or dorsiflexion, and an Ant/Post pair accelerates the foot anteriorly or posteriorly relative to the pelvis. Because each biomechanical function (i.e., Ext, Flex, Plant, Dorsi, Ant, or Post) contributes to crank propulsion during a specific region in the cycle, phasing of a muscle is hypothesized to be a consequence of its ability to contribute to one or more of the biomechanical functions. Analysis of electromyogram (EMG) patterns has shown that this biomechanical framework assists in the interpretation of muscle activity in healthy and hemiparetic subjects during forward pedaling. Simulations show that backward pedaling can be produced with a phase shift of 180 degrees in the Ant/Post pair. No phase shifts in the Ext/Flex and Plant/Dorsi pairs are then necessary. To further test whether this simple yet biomechanically viable strategy may be used by the nervous system, EMGs from 7 muscles in 16 subjects were measured during backward as well as forward pedaling. As predicted, phasing in vastus medialis (VM), tibialis anterior (TA), medial gastrocnemius (MG), and soleus (SL) were unaffected by pedaling direction, with VM and SL contributing to Ext, MG to Plant, and TA to Dorsi. In contrast, phasing in biceps femoris (BF) and semimembranosus (SM) were affected by pedaling direction, as predicted, compatible with their contribution to the directionally sensitive Post function. Phasing of rectus femoris (RF) was also affected by pedaling direction; however, its ability to contribute to the directionally sensitive Ant function may only be expressed in forward pedaling. RF also contributed significantly to

Simulated parallel annealing within a neighborhood for optimization of biomechanical systems.

Science.gov (United States)

Higginson, J S; Neptune, R R; Anderson, F C

2005-09-01

Optimization problems for biomechanical systems have become extremely complex. Simulated annealing (SA) algorithms have performed well in a variety of test problems and biomechanical applications; however, despite advances in computer speed, convergence to optimal solutions for systems of even moderate complexity has remained prohibitive. The objective of this study was to develop a portable parallel version of a SA algorithm for solving optimization problems in biomechanics. The algorithm for simulated parallel annealing within a neighborhood (SPAN) was designed to minimize interprocessor communication time and closely retain the heuristics of the serial SA algorithm. The computational speed of the SPAN algorithm scaled linearly with the number of processors on different computer platforms for a simple quadratic test problem and for a more complex forward dynamic simulation of human pedaling.

Primary fixation of mini slings: a comparative biomechanical study in vivo

Directory of Open Access Journals (Sweden)

Paulo Palma

2012-04-01

Full Text Available INTRODUCTION AND OBJECTIVES: The mini sling concept for stress urinary incontinence is an anatomical approach that involves placing a midurethral low-tension tape anchored to the obturator internus muscles bilaterally. They overcome the blind passage of long needles and all the related complications. There are many different devices available and because these are outpatient procedures, primary fixation plays an important role in the outcome. The objective is to evaluate the primary fixation of the various devices of attachment of the commercially available mini-slings through biomechanical tests. MATERIALS AND METHODS: A total of 45 Wistar rats were divided in 3 groups of 15 rats each. They underwent 5 subcutaneous implantation of different mini slings and one polipropilene mesh (control, as follows: TVT-Secur® (Gynecare, USA, Type 1 polypropylene mesh (control; Ophira Mini Sling System® (Promedon, Argentina, Tissue Fixation System® (TFS PTY, Australia, Zipper Sling® and "T device" (Prosurg, USA. The abdominal wall was removed on bloc at different times after implant for biomechanical evaluation, which consisted in application of unidirectional force to the extremity of the fixation system or mesh, until it was completely removed from the tissue using a tension meter (Nexygen 3.0 Universal Testing Machine - LLOYD Instruments. The force was measured in Newtons (N. RESULTS: There was significant difference in the resistance to extraction among the different fixation systems. At 7 days the Ophira Mini Sling System® presented the best fixation and "T dispositive" the worst. CONCLUSION: Ophira mini sling System® presented the best primary fixation at 7º, 14º and 30º days. The impact of this feature in the clinical setting needs to be verified.

Anabolic androgenic steroids reverse the beneficial effect of exercise on tendon biomechanics: an experimental study.

Science.gov (United States)

Tsitsilonis, Serafim; Chatzistergos, Panayiotis E; Panayiotis, Chatzistergos E; Mitousoudis, Athanasios S; Athanasios, Mitousoudis S; Kourkoulis, Stavros K; Stavros, Kourkoulis K; Vlachos, Ioannis S; Ioannis, Vlachos S; Agrogiannis, George; George, Agrogiannis; Fasseas, Konstantinos; Konstantinos, Fasseas; Perrea, Despina N; Despina, Perrea N; Zoubos, Aristides B; Aristides, Zoubos B

2014-06-01

The effect of anabolic androgenic steroids on tendons has not yet been fully elucidated. Aim of the present study was the evaluation of the impact of anabolic androgenic steroids on the biomechanical and histological characteristics of Achilles tendons. Twenty-four male Wistar rats were randomized into four groups with exercise and anabolic steroids (nandrolone decanoate) serving as variables. Protocol duration was 12 weeks. Following euthanasia, tendons' biomechanical properties were tested with the use of a modified clamping configuration. Histological examination with light and electron microscopy were also performed. In the group of anabolic steroids and exercise the lowest fracture stress values were observed, while in the exercise group the highest ones. Histological examination by light and electron microscopy revealed areas of collagen dysplasia and an increased epitendon in the groups receiving anabolic steroids and exercise. These findings suggest that anabolic androgenic steroids reverse the beneficial effect of exercise, thus resulting in inferior maximal stress values. Copyright © 2013 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved.

Biomechanics of the thorax – research evidence and clinical expertise

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Lee, Diane Gail

2015-01-01

Understanding the biomechanics of the thorax is critical for understanding its role in multiple conditions since the thorax is part of many integrated systems including the musculoskeletal, respiratory, cardiac, digestive and urogynecological. The thorax is also an integrated system within itself and an element of the whole body/person. Therefore, understanding the biomechanics of the thorax is fundamental to all forms of treatment for multiple conditions. The interpretation of movement examination findings depends on one's view of optimal biomechanics and the influential factors. This article will provide a synopsis of the current state of research evidence as well as observations from clinical experience pertaining to the biomechanics of the thorax in order to help clinicians organise this knowledge and facilitate evidence-based and informed management of the, often complex, patient with or without thoracic pain and impairment. The integrated systems model (ISM) will be introduced as a way to determine when the noted biomechanical findings are relevant to a patient's clinical presentation. PMID:26309383

Effects of Bone Young’s Modulus on Finite Element Analysis in the Lateral Ankle Biomechanics

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W. X. Niu

2013-01-01

Full Text Available Finite element analysis (FEA is a powerful tool in biomechanics. The mechanical properties of biological tissue used in FEA modeling are mainly from experimental data, which vary greatly and are sometimes uncertain. The purpose of this study was to research how Young’s modulus affects the computations of a foot-ankle FEA model. A computer simulation and an in-vitro experiment were carried out to investigate the effects of incremental Young’s modulus of bone on the stress and strain outcomes in the computational simulation. A precise 3-dimensional finite element model was constructed based on an in-vitro specimen of human foot and ankle. Young’s moduli were assigned as four levels of 7.3, 14.6, 21.9 and 29.2 GPa respectively. The proximal tibia and fibula were completely limited to six degrees of freedom, and the ankle was loaded to inversion 10° and 20° through the calcaneus. Six cadaveric foot-ankle specimens were loaded as same as the finite element model, and strain was measured at two positions of the distal fibula. The bone stress was less affected by assignment of Young’s modulus. With increasing of Young’s modulus, the bone strain decreased linearly. Young’s modulus of 29.2 GPa was advisable to get the satisfactory surface strain results. In the future study, more ideal model should be constructed to represent the nonlinearity, anisotropy and inhomogeneity, as the same time to provide reasonable outputs of the interested parameters.

BIOMECHANIC EVALUATION OF CARPENTRY WORKERS IN THE DISTRITO FEDERAL, BRAZIL

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Nilton Cesar Fiedler

2010-08-01

Full Text Available The aim of this study was the biomechanical assessment of carpentry woodworkers, located in Brasília, DF. It was filmed the profile of each worker during the performance of his activities in the carpentry and the forces involved in the work were assessed. The image of each woodworker was congealed to accomplish the measurement of articulation angles. The data were submitted to the software of posture analysis “Winowas” (OWAS Method and to the biomechanic model of posture prognosis and static forces, developed by Michigan University. The OWAS method showed that, for all machines and carpentries assessed, the worst posture occurred when the worker lifted and placed the pieces of wood on the floor and during the feeding in the smoother. The tridimensional biomechanic model registered the worst posture in different phases of the work cycle. In the first one, there were problems in all articulations, except the hips, when placing the pieces on the floor from the smoother. In the second one, there were problems in all articulations, except the elbows and the L5-S1 column disc, by feeding the surface planer. The third one, the ankles were the most injured when feeding the smoother, the surface planer, the circular saw and the band saw. According to the results, the woodworkers should try to eliminate the constant work standing upright, use auxiliary machinery to handle pieces of wood, reduce the load during feeding the machines and improve postures.

In Vivo Corneal Biomechanical Properties with Corneal Visualization Scheimpflug Technology in Chinese Population

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Ying Wu

2016-01-01

Full Text Available Purpose. To determine the repeatability of recalculated corneal visualization Scheimpflug technology (CorVis ST parameters and to study the variation of biomechanical properties and their association with demographic and ocular characteristics. Methods. A total of 783 healthy subjects were included in this study. Comprehensive ophthalmological examinations were conducted. The repeatability of the recalculated biomechanical parameters with 90 subjects was assessed by the coefficient of variation (CV and intraclass correlation coefficient (ICC. Univariate and multivariate linear regression models were used to identify demographic and ocular factors. Results. The repeatability of the central corneal thickness (CCT, deformation amplitude (DA, and first/second applanation time (A1/A2-time exhibited excellent repeatability (CV% ≤ 3.312% and ICC ≥ 0.929 for all measurements. The velocity in/out (Vin/out, highest concavity- (HC- radius, peak distance (PD, and DA showed a normal distribution. Univariate linear regression showed a statistically significant correlation between Vin, Vout, DA, PD, and HC-radius and IOP, CCT, and corneal volume, respectively. Multivariate analysis showed that IOP and CCT were negatively correlated with Vin, DA, and PD, while there was a positive correlation between Vout and HC-radius. Conclusion. The ICCs of the recalculated parameters, CCT, DA, A1-time, and A2-time, exhibited excellent repeatability. IOP, CCT, and corneal volume significantly influenced the biomechanical properties of the eye.

Computational biomechanics for medicine imaging, modeling and computing

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Doyle, Barry; Wittek, Adam; Nielsen, Poul; Miller, Karol

2016-01-01

The Computational Biomechanics for Medicine titles provide an opportunity for specialists in computational biomechanics to present their latest methodologies and advancements. This volume comprises eighteen of the newest approaches and applications of computational biomechanics, from researchers in Australia, New Zealand, USA, UK, Switzerland, Scotland, France and Russia. Some of the interesting topics discussed are: tailored computational models; traumatic brain injury; soft-tissue mechanics; medical image analysis; and clinically-relevant simulations. One of the greatest challenges facing the computational engineering community is to extend the success of computational mechanics to fields outside traditional engineering, in particular to biology, the biomedical sciences, and medicine. We hope the research presented within this book series will contribute to overcoming this grand challenge.

Functional modeling of the craniospinal system for in-vitro parameter studies on the pathogenesis of NPH

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Benninghaus Anne

2017-09-01

Full Text Available Normal Pressure Hydrocephalus (NPH has become a common disease in the elderly coming along with typical symptoms of dementia, gait ataxia and urinary incontinence, which make the differential diagnosis with other forms of dementia difficult. Furthermore the pathogenesis of NPH is still not understood. About 10% of all demented patients might be suffering from NPH [1]. Many hypotheses suggest that modified biomechanical boundary conditions affect the craniospinal dynamics inducing the pathogenesis of NPH. We present a novel approach for an in-vitro model of the craniospinal system to investigate important hydrodynamic influences on the system such as (dynamic compliance of the vascular system and especially the spinal subarachnoid space (SAS as well as reabsorption and hydrostatics. The experimental set-up enables the individual adjustment of relevant parameters for sensitivity analyses regarding the impact of resulting CSF dynamics on the pathogenesis of NPH.

The effect of a daily quiz (TOPday) on self-confidence, enthusiasm, and test results for biomechanics.

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Tanck, Esther; Maessen, Martijn F H; Hannink, Gerjon; van Kuppeveld, Sascha M H F; Bolhuis, Sanneke; Kooloos, Jan G M

2014-01-01

Many students in Biomedical Sciences have difficulty understanding biomechanics. In a second-year course, biomechanics is taught in the first week and examined at the end of the fourth week. Knowledge is retained longer if the subject material is repeated. However, how does one encourage students to repeat the subject matter? For this study, we developed 'two opportunities to practice per day (TOPday)', consisting of multiple-choice questions on biomechanics with immediate feedback, which were sent via e-mail. We investigated the effect of TOPday on self-confidence, enthusiasm, and test results for biomechanics. All second-year students (n = 95) received a TOPday of biomechanics on every regular course day with increasing difficulty during the course. At the end of the course, a non-anonymous questionnaire was conducted. The students were asked how many TOPday questions they completed (0-6 questions [group A]; 7-18 questions [group B]; 19-24 questions [group C]). Other questions included the appreciation for TOPday, and increase (no/yes) in self-confidence and enthusiasm for biomechanics. Seventy-eight students participated in the examination and completed the questionnaire. The appreciation for TOPday in group A (n = 14), B (n = 23) and C (n = 41) was 7.0 (95 % CI 6.5-7.5), 7.4 (95 % CI 7.0-7.8), and 7.9 (95 % CI 7.6-8.1), respectively (p biomechanics due to TOPday. In addition, they had a higher test result for biomechanics (p biomechanics on the other.

A biomechanical assessment to evaluate breed differences in normal porcine medial collateral ligaments.

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Germscheid, Niccole M; Thornton, Gail M; Hart, David A; Hildebrand, Kevin A

2011-02-24

Little information is available on the role of genetic factors and heredity in normal ligament behaviour and their ability to heal. Assessing these factors is challenging because of the lack of suitable animal models. Therefore, the purpose of this study was to develop a porcine model in order to evaluate and compare the biomechanical differences of normal medial collateral ligaments (MCLs) between Yorkshire (YK) and red Duroc (RD) breeds. It was hypothesized that biomechanical differences would not exist between normal YK and RD MCLs. Comparisons between porcine and human MCL were also made. A biomechanical testing apparatus and protocol specific to pig MCL were developed. Ligaments were subjected to cyclic and static creep tests and then elongated to failure. Pig MCL morphology, geometry, and low- and high-load mechanical behaviour were assessed. The custom-designed apparatus and protocol were sufficiently sensitive to detect mechanical property differences between breeds as well as inter-leg differences. The results reveal that porcine MCL is comparable in both shape and size to human MCL and exhibits similar structural and material failure properties, thus making it a feasible model. Comparisons between RD and YK breeds revealed that age-matched RD pigs weigh more, have larger MCL cross-sectional area, and have lower MCL failure stress than YK pigs. The effect of weight may have influenced MCL geometrical and biomechanical properties, and consequently, the differences observed may be due to breed type and/or animal weight. In conclusion, the pig serves as a suitable large animal model for genetic-related connective tissue studies. Copyright © 2010 Elsevier Ltd. All rights reserved.

Current Biomechanical Concepts for Rotator Cuff Repair

Science.gov (United States)

2013-01-01

For the past few decades, the repair of rotator cuff tears has evolved significantly with advances in arthroscopy techniques, suture anchors and instrumentation. From the biomechanical perspective, the focus in arthroscopic repair has been on increasing fixation strength and restoration of the footprint contact characteristics to provide early rehabilitation and improve healing. To accomplish these objectives, various repair strategies and construct configurations have been developed for rotator cuff repair with the understanding that many factors contribute to the structural integrity of the repaired construct. These include repaired rotator cuff tendon-footprint motion, increased tendon-footprint contact area and pressure, and tissue quality of tendon and bone. In addition, the healing response may be compromised by intrinsic factors such as decreased vascularity, hypoxia, and fibrocartilaginous changes or aforementioned extrinsic compression factors. Furthermore, it is well documented that torn rotator cuff muscles have a tendency to atrophy and become subject to fatty infiltration which may affect the longevity of the repair. Despite all the aforementioned factors, initial fixation strength is an essential consideration in optimizing rotator cuff repair. Therefore, numerous biomechanical studies have focused on elucidating the strongest devices, knots, and repair configurations to improve contact characteristics for rotator cuff repair. In this review, the biomechanical concepts behind current rotator cuff repair techniques will be reviewed and discussed. PMID:23730471

The Undergraduate Biomechanics Experience at Iowa State University.

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Francis, Peter R.

This paper discusses the objectives of a program in biomechanics--the analysis of sports skills and movement--and the evolution of the biomechanics program at Iowa State University. The primary objective of such a course is to provide the student with the basic tools necessary for adequate analysis of human movement, with special emphasis upon…

Biomechanical Response and Behavior of Users under Emergency Buffer Crash

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R. Miralbes

2013-01-01

Full Text Available This paper aims to study the biomechanical effects on elevator users and the injuries sustained should an elevator crash happen. The analysis will focus on buffer impact, signaling that the earlier mentioned buffer is usually located at the bottom of the pit. In order to carry out this analysis, a numerical technique based on finite element method will be used, while elevator users will be simulated by means of automotive dummies. Two crash factors will be studied, namely, location of dummy and fall velocity. The analysis criteria will be damages sustained by the dummy, based on biomechanical index such as HIC, CSI, forces, and accelerations.

The Influence of Lower Extremity Lean Mass on Landing Biomechanics During Prolonged Exercise.

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Montgomery, Melissa M; Tritsch, Amanda J; Cone, John R; Schmitz, Randy J; Henson, Robert A; Shultz, Sandra J

2017-08-01

  The extent to which lower extremity lean mass (LELM) relative to total body mass influences one's ability to maintain safe landing biomechanics during prolonged exercise when injury incidence increases is unknown.   To examine the influence of LELM on (1) pre-exercise lower extremity biomechanics and (2) changes in biomechanics during an intermittent exercise protocol (IEP) and (3) determine whether these relationships differ by sex. We hypothesized that less LELM would predict higher-risk baseline biomechanics and greater changes toward higher-risk biomechanics during the IEP.   Cohort study.   Controlled laboratory.   A total of 59 athletes (30 men: age = 20.3 ± 2.0 years, height = 1.79 ± 0.05 m, mass = 75.2 ± 7.2 kg; 29 women: age = 20.6 ± 2.3 years, height = 1.67 ± 0.08 m, mass = 61.8 ± 9.0 kg) participated.   Before completing an individualized 90-minute IEP designed to mimic a soccer match, participants underwent dual-energy x-ray absorptiometry testing for LELM.   Three-dimensional lower extremity biomechanics were measured during drop-jump landings before the IEP and every 15 minutes thereafter. A previously reported principal components analysis reduced 40 biomechanical variables to 11 factors. Hierarchical linear modeling analysis then determined the extent to which sex and LELM predicted the baseline score and the change in each factor over time.   Lower extremity lean mass did not influence baseline biomechanics or the changes over time. Sex influenced the biomechanical factor representing knee loading at baseline (P = .04) and the changes in the anterior cruciate ligament-loading factor over time (P = .03). The LELM had an additional influence only on women who possessed less LELM (P = .03 and .02, respectively).   Lower extremity lean mass influenced knee loading during landing in women but not in men. The effect appeared to be stronger in women with less LELM. Continually decreasing knee loading over time may reflect a

Relationship between the Modified Modified Ashworth Scale and the Biomechanical Measure in Assessing Knee Extensor Muscle Spasticity in Patients with Post-Stroke Hemiparesia:A Pilot Study

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N. Nakhostin Ansari

2014-07-01

Full Text Available Introduction & Objective: The Modified Modified Ashworth Scale (MMAS is a clinical meas-ure that has been recently developed for the assessment of muscle spasticity. There is a dearth of research on the validity of the MMAS. The aim of the present study was to investi-gate the relationship between the MMAS and the biomechanical measure of work-velocity slope in assessing knee extensor muscle spasticity in patients with hemiparesia. Materials & Methods: Fourteen patients with post-stroke hemiparesia were included in this cross sectional study. Knee extensor spasticity was assessed with MMAS. An isokinetic dy-namometer was used to impose knee passive flexion with the angular velocity of 10, 30, 60, and 90 °/Sec to measure Torque-angle data. Work (Joule was calculated at each velocity to determine the slope of the work-velocity curves as the biomechanical measure of muscle spasticity. Results: The mean work decreased as the velocity increased but was not statistically signifi-cant (P = 0.07. The mean slope was – 0.35 [J /(°/Sec]. There was no significant correlation between the MMAS and the work-velocity slope (r =0.31, P = 0.28. Conclusion: There was no significant relationship between the MMAS and the biomechanical measure of work-velocity slope. Further studies with larger sample size are suggested. (Sci J Hamadan Univ Med Sci 2014; 21 (2: 131-136

Tensile strength comparison between peroneus longus and hamstring tendons: A biomechanical study

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Rudy

2017-01-01

Conclusion: The tensile strength of the peroneus longus tendon, which is similar to that of hamstring, gives information that both have the same biomechanic properties. Peroneus longus should not be used as a first option in ACL reconstruction, but may be used as an alternative donor in cases involving multiple instability that require more tendon donors in the reconstruction.

The Biomechanical Role of Scaffolds in Augmented Rotator Cuff Tendon Repairs

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2012-01-01

The biomechanical role of scaffolds in augmented rotator cuff tendon repairs Amit Aurora, D Enga,b, Jesse A. McCarron, MDc, Antonie J. van den Bogert...used for rotator cuff repair augmentation; however, the appropriate scaffold material properties and/or surgical application techniques for achieving...The model predicts that the biomechanical performance of a rotator cuff repair can be modestly increased by augmenting the repair with a scaffold that

Image-assisted non-invasive and dynamic biomechanical analysis of human joints

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Muhit, Abdullah A; Pickering, Mark R; Scarvell, Jennifer M; Ward, Tom; Smith, Paul N

2013-01-01

Kinematic analysis provides a strong link between musculoskeletal injuries, chronic joint conditions, treatment planning/monitoring and prosthesis design/outcome. However, fast and accurate 3D kinematic analysis still remains a challenge in order to translate this procedure into clinical scenarios. 3D computed tomography (CT) to 2D single-plane fluoroscopy registration is a promising non-invasive technology for biomechanical examination of human joints. Although this technique has proven to be very precise in terms of in-plane translation and rotation measurements, out-of-plane motion estimations have been a difficulty so far. Therefore, to enable this technology into clinical translation, precise and fast estimation of both in-plane and out-of-plane movements is crucial, which is the aim of this paper. Here, a fast and accurate 3D/2D registration technique is proposed to evaluate biomechanical/kinematic analysis. The proposed algorithm utilizes a new multi-modal similarity measure called ‘sum of conditional variances’, a coarse-to-fine Laplacian of Gaussian filtering approach for robust gradient-descent optimization and a novel technique for the analytic calculation of the required gradients for out-of-plane rotations. Computer simulations and in vitro experiments showed that the new approach was robust in terms of the capture range, required significantly less iterations to converge and achieved good registration and kinematic accuracy when compared to existing techniques and to the ‘gold-standard’ Roentgen stereo analysis. (paper)

Biomechanics of Pediatric Manual Wheelchair Mobility.

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Slavens, Brooke A; Schnorenberg, Alyssa J; Aurit, Christine M; Tarima, Sergey; Vogel, Lawrence C; Harris, Gerald F

2015-01-01

Currently, there is limited research of the biomechanics of pediatric manual wheelchair mobility. Specifically, the biomechanics of functional tasks and their relationship to joint pain and health is not well understood. To contribute to this knowledge gap, a quantitative rehabilitation approach was applied for characterizing upper extremity biomechanics of manual wheelchair mobility in children and adolescents during propulsion, starting, and stopping tasks. A Vicon motion analysis system captured movement, while a SmartWheel simultaneously collected three-dimensional forces and moments occurring at the handrim. A custom pediatric inverse dynamics model was used to evaluate three-dimensional upper extremity joint motions, forces, and moments of 14 children with spinal cord injury (SCI) during the functional tasks. Additionally, pain and health-related quality of life outcomes were assessed. This research found that joint demands are significantly different amongst functional tasks, with greatest demands placed on the shoulder during the starting task. Propulsion was significantly different from starting and stopping at all joints. We identified multiple stroke patterns used by the children, some of which are not standard in adults. One subject reported average daily pain, which was minimal. Lower than normal physical health and higher than normal mental health was found in this population. It can be concluded that functional tasks should be considered in addition to propulsion for rehabilitation and SCI treatment planning. This research provides wheelchair users and clinicians with a comprehensive, biomechanical, mobility assessment approach for wheelchair prescription, training, and long-term care of children with SCI.

Relations between Biomechanical Parameters and Static Power of Arms in Children with Disturbed Posture

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Slobodan Andrašić

2017-02-01

Full Text Available This study is aimed at determining the parameters and biomechanical analysis of their impact on the static arm strength in children with impaired posture as poor kyphotic posture, lordotic poor posture and children with flat feet. A transversal study included a sample of 67 children on the territory of the municipality of Subotica. The structure of the sample is as follows: 22 subjects with impaired kyphotic posture, 18 patients with impaired lordotic posture, and 27 subjects with flat feet. Measuring the level of static arm strength was done by the standardized "folding endurance" test. Observing the morphological development of children with kyphotic, lordotic poor posture and flat feet determined statistically significant differences in biomechanical variables.

The biomechanical influence of the deltotrapezoid fascia on horizontal and vertical acromioclavicular joint stability.

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Pastor, M F; Averbeck, A K; Welke, B; Smith, T; Claassen, L; Wellmann, M

2016-04-01

Many studies have investigated the biomechanical influence of the acromioclavicular (AC) and coracoclavicular (CC) ligaments on the stability of the acromioclavicular joint (ACJ). It has been shown that augmentation of the CC ligaments alone can result in residual horizontal instability. Our hypothesis was that the DTF would have a significant stabilizing effect on horizontal ACJ stability. In a biomechanical in vitro study a sequential injury of the ACJ was created on eight shoulders from full body, which were placed in an upright sitting position. The translation and rotation of the clavicle were measured in relation to the acromion using an optical navigation system in various states during thoracic-humeral elevation, abduction, and horizontal adduction. The three states were: an intact shoulder, complete sectioning of the AC ligaments, and a circular lesion of the DTF. Compared to the intact state we found a significant increase in anterior rotation of the clavicle of 1.11° (p = 0.012) and a tendency in lateral translation of 2.71 mm (p = 0.017) in relation to the acromion, with a combined lesion of AC ligaments and DTF. No significant differences were found between the intact state and the isolated dissected AC ligaments as well in adduction as elevation. A combined lesion of the AC ligaments and the DTF resulted in a quantitatively small but significant increase in anterior rotation and a tendency in lateral translation of the clavicle in relation to the acromion. These differences were quantitatively small, so that the clinical relevance of the stabilization effect of combined AC ligaments and DTF injuries is questionable.

Evaluation of Corneal Topography and Biomechanical Parameters after Use of Systemic Isotretinoin in Acne Vulgaris

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Yusuf Yildirim

2014-01-01

Full Text Available Purpose. We report the effect of isotretinoin on corneal topography, corneal thickness, and biomechanical parameters in patients with acne vulgaris. Method. Fifty-four eyes of 54 patients who received oral isotretinoin for treatment of acne vulgaris were evaluated. All patients underwent a corneal topographical evaluation with a Scheimpflug camera combined with Placido-disk (Sirius, ultrasonic pachymetry measurements, and corneal biomechanical evaluation with an ocular response analyzer at baseline, in the 1st, 3rd, and 6th months of treatment, and 6 months after isotretinoin discontinuation. Results. The thinnest corneal thickness measured with Sirius differed significantly in the 1st, 3rd, and 6th months compared with the baseline measurement; there was no significant change in ultrasonic central corneal thickness measurements and biomechanical parameters (corneal hysteresis and corneal resistance factor throughout the study. Average simulated keratometry and surface asymmetry index increased significantly only in the first month of treatment according to the baseline. All changes disappeared 6 months after the end of treatment. Conclusion. Basal tear secretion and corneal morphologic properties were significantly influenced during the systemic isotretinoin treatment and the changes were reversible after discontinuation. No statistical important biomechanical differences were found to be induced by isotretinoin.

Optical spectroscopic characterization of human meniscus biomechanical properties

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Ala-Myllymäki, Juho; Danso, Elvis K.; Honkanen, Juuso T. J.; Korhonen, Rami K.; Töyräs, Juha; Afara, Isaac O.

2017-12-01

This study investigates the capacity of optical spectroscopy in the visible (VIS) and near-infrared (NIR) spectral ranges for estimating the biomechanical properties of human meniscus. Seventy-two samples obtained from the anterior, central, and posterior locations of the medial and lateral menisci of 12 human cadaver joints were used. The samples were subjected to mechanical indentation, then traditional biomechanical parameters (equilibrium and dynamic moduli) were calculated. In addition, strain-dependent fibril network modulus and permeability strain-dependency coefficient were determined via finite-element modeling. Subsequently, absorption spectra were acquired from each location in the VIS (400 to 750 nm) and NIR (750 to 1100 nm) spectral ranges. Partial least squares regression, combined with spectral preprocessing and transformation, was then used to investigate the relationship between the biomechanical properties and spectral response. The NIR spectral region was observed to be optimal for model development (83.0%≤R2≤90.8%). The percentage error of the models are: Eeq (7.1%), Edyn (9.6%), Eɛ (8.4%), and Mk (8.9%). Thus, we conclude that optical spectroscopy in the NIR range is a potential method for rapid and nondestructive evaluation of human meniscus functional integrity and health in real time during arthroscopic surgery.

Needle puncture in rabbit functional spinal units alters rotational biomechanics.

Science.gov (United States)

Hartman, Robert A; Bell, Kevin M; Quan, Bichun; Nuzhao, Yao; Sowa, Gwendolyn A; Kang, James D

2015-04-01

An in vitro biomechanical study for rabbit lumbar functional spinal units (FSUs) using a robot-based spine testing system. To elucidate the effect of annular puncture with a 16 G needle on mechanical properties in flexion/extension, axial rotation, and lateral bending. Needle puncture of the intervertebral disk has been shown to alter mechanical properties of the disk in compression, torsion, and bending. The effect of needle puncture in FSUs, where intact spinal ligaments and facet joints may mitigate or amplify these changes in the disk, on spinal motion segment stability subject to physiological rotations remains unknown. Rabbit FSUs were tested using a robot testing system whose force/moment and position precision were assessed to demonstrate system capability. Flexibility testing methods were developed by load-to-failure testing in flexion/extension, axial rotation, and lateral bending. Subsequent testing methods were used to examine a 16 G needle disk puncture and No. 11 blade disk stab (positive control for mechanical disruption). Flexibility testing was used to assess segmental range-of-motion (degrees), neutral zone stiffness (N m/degrees) and width (degrees and N m), and elastic zone stiffness before and after annular injury. The robot-based system was capable of performing flexibility testing on FSUs-mean precision of force/moment measurements and robot system movements were elastic zone stiffness in flexion and lateral bending. These findings suggest that disk puncture and stab can destabilize FSUs in primary rotations.

MRI and CT lung biomarkers: Towards an in vivo understanding of lung biomechanics.

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Young, Heather M; Eddy, Rachel L; Parraga, Grace

2017-09-29

The biomechanical properties of the lung are necessarily dependent on its structure and function, both of which are complex and change over time and space. This makes in vivo evaluation of lung biomechanics and a deep understanding of lung biomarkers, very challenging. In patients and animal models of lung disease, in vivo evaluations of lung structure and function are typically made at the mouth and include spirometry, multiple-breath gas washout tests and the forced oscillation technique. These techniques, and the biomarkers they provide, incorporate the properties of the whole organ system including the parenchyma, large and small airways, mouth, diaphragm and intercostal muscles. Unfortunately, these well-established measurements mask regional differences, limiting their ability to probe the lung's gross and micro-biomechanical properties which vary widely throughout the organ and its subcompartments. Pulmonary imaging has the advantage in providing regional, non-invasive measurements of healthy and diseased lung, in vivo. Here we summarize well-established and emerging lung imaging tools and biomarkers and how they may be used to generate lung biomechanical measurements. We review well-established and emerging lung anatomical, microstructural and functional imaging biomarkers generated using synchrotron x-ray tomographic-microscopy (SRXTM), micro-x-ray computed-tomography (micro-CT), clinical CT as well as magnetic resonance imaging (MRI). Pulmonary imaging provides measurements of lung structure, function and biomechanics with high spatial and temporal resolution. Imaging biomarkers that reflect the biomechanical properties of the lung are now being validated to provide a deeper understanding of the lung that cannot be achieved using measurements made at the mouth. Copyright © 2017 Elsevier Ltd. All rights reserved.

Understanding how axial loads on the spine influence segmental biomechanics for idiopathic scoliosis patients: A magnetic resonance imaging study.

Science.gov (United States)

Little, J P; Pearcy, M J; Izatt, M T; Boom, K; Labrom, R D; Askin, G N; Adam, C J

2016-02-01

Segmental biomechanics of the scoliotic spine are important since the overall spinal deformity is comprised of the cumulative coronal and axial rotations of individual joints. This study investigates the coronal plane segmental biomechanics for adolescent idiopathic scoliosis patients in response to physiologically relevant axial compression. Individual spinal joint compliance in the coronal plane was measured for a series of 15 idiopathic scoliosis patients using axially loaded magnetic resonance imaging. Each patient was first imaged in the supine position with no axial load, and then again following application of an axial compressive load. Coronal plane disc wedge angles in the unloaded and loaded configurations were measured. Joint moments exerted by the axial compressive load were used to derive estimates of individual joint compliance. The mean standing major Cobb angle for this patient series was 46°. Mean intra-observer measurement error for endplate inclination was 1.6°. Following loading, initially highly wedged discs demonstrated a smaller change in wedge angle, than less wedged discs for certain spinal levels (+2,+1,-2 relative to the apex, (pbiomechanical data on in vivo spinal biomechanics of the scoliotic spine, for analysis of deformity progression and surgical planning. Copyright © 2015 Elsevier Ltd. All rights reserved.

Associations between iliotibial band injury status and running biomechanics in women.

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Foch, Eric; Reinbolt, Jeffrey A; Zhang, Songning; Fitzhugh, Eugene C; Milner, Clare E

2015-02-01

Iliotibial band syndrome (ITBS) is a common overuse knee injury that is twice as likely to afflict women compared to men. Lower extremity and trunk biomechanics during running, as well as hip abductor strength and iliotibial band flexibility, are factors believed to be associated with ITBS. The purpose of this cross-sectional study was to determine if differences in lower extremity and trunk biomechanics during running exist among runners with current ITBS, previous ITBS, and controls. Additionally, we sought to determine if isometric hip abductor strength and iliotibial band flexibility were different among groups. Twenty-seven female runners participated in the study. Participants were divided into three equal groups: current ITBS, previous ITBS, and controls. Overground running trials, isometric hip abductor strength, and iliotibial band flexibility were recorded for all participants. Discrete joint and segment biomechanics, as well as hip strength and flexibility measures were analyzed using a one-way analysis of variance. Runners with current ITBS exhibited 1.8 (1.5)° greater trunk ipsilateral flexion and 7 (6)° less iliotibial band flexibility compared to runners with previous ITBS and controls. Runners with previous ITBS exhibited 2.2 (2.9) ° less hip adduction compared to runners with current ITBS and controls. Hip abductor strength 3.3 (2.6) %BM×h was less in runners with previous ITBS but not current ITBS compared to controls. Runners with current ITBS may lean their trunk more towards the stance limb which may be associated with decreased iliotibial band flexibility. Copyright © 2015 Elsevier B.V. All rights reserved.

Physiological, biomechanical and anthropometrical predictors of sprint swimming performance in adolescent swimmers.

Science.gov (United States)

Lätt, Evelin; Jürimäe, Jaak; Mäestu, Jarek; Purge, Priit; Rämson, Raul; Haljaste, Kaja; Keskinen, Kari L; Rodriguez, Ferran A; Jürimäe, Toivo

2010-01-01

The purpose of this study was to analyze the relationships between 100-m front crawl swimming performance and relevant biomechanical, anthropometrical and physiological parameters in male adolescent swimmers. Twenty five male swimmers (mean ± SD: age 15. 2 ± 1.9 years; height 1.76 ± 0.09 m; body mass 63.3 ± 10.9 kg) performed an all-out 100-m front crawl swimming test in a 25-m pool. A respiratory snorkel and valve system with low hydrodynamic resistance was used to collect expired air. Oxygen uptake was measured breath-by-breath by a portable metabolic cart. Swimming velocity, stroke rate (SR), stroke length and stroke index (SI) were assessed during the test by time video analysis. Blood samples for lactate measurement were taken from the fingertip pre exercise and at the third and fifth minute of recovery to estimate net blood lactate accumulation (ΔLa). The energy cost of swimming was estimated from oxygen uptake and blood lactate energy equivalent values. Basic anthropometry included body height, body mass and arm span. Body composition parameters were measured using dual-energy X-ray absorptiometry (DXA). Results indicate that biomechanical factors (90.3%) explained most of 100-m front crawl swimming performance variability in these adolescent male swimmers, followed by anthropometrical (45.8%) and physiological (45.2%) parameters. SI was the best single predictor of performance, while arm span and ∆La were the best anthropometrical and physiological indicators, respectively. SI and SR alone explained 92.6% of the variance in competitive performance. These results confirm the importance of considering specific stroke technical parameters when predicting success in young swimmers. Key pointsThis study investigated the influence of different anthropometrical, physiological and biomechanical parameters on 100-m swimming performance in adolescent boys.Biomechanical factors contributed most to sprint swimming performance in these young male swimmers (90

Lumbar Spine Musculoskeletal Physiology and Biomechanics During Simulated Military Operations

Science.gov (United States)

2016-06-01

AWARD NUMBER: W81XWH-13-2-0043 TITLE: Lumbar Spine Musculoskeletal Physiology and Biomechanics During Simulated Military Operations PRINCIPAL...31May2016 4. TITLE AND SUBTITLE Lumbar Spine Musculoskeletal Physiology and Biomechanics 5a. CONTRACT NUMBER During Simulated Military Operations 5b... Biomechanics , Cincinnati, 2015. § Website(s) or other Internet site(s) § Nothing to report § Technologies or techniques § Nothing to report

Preliminary evidence of altered biomechanics in adolescents with juvenile fibromyalgia.

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Sil, Soumitri; Thomas, Staci; DiCesare, Christopher; Strotman, Daniel; Ting, Tracy V; Myer, Gregory; Kashikar-Zuck, Susmita

2015-01-01

Juvenile fibromyalgia (FM) is characterized by chronic musculoskeletal pain and marked reduction in physical activity. Despite recommendations for exercise to manage juvenile FM pain, exercise adherence is poor. Because of pain and activity avoidance, adolescents with juvenile FM are at risk for altered joint mechanics that may make them susceptible to increased pain and reduced tolerance for exercise. The primary aim of this study was to assess functional deficits in patients with juvenile FM compared to healthy controls using objective biomechanical assessment. Female adolescent patients with juvenile FM (n = 17) and healthy controls (n = 14) completed biomechanical assessments, including gait analysis and tests of lower extremity strength (isokinetic knee extension/flexion and hip abduction) and functional performance (drop vertical jump test) along with self-reported measures of disability (Functional Disability Inventory), pain intensity, depressive symptoms (Children's Depression Inventory), and fear of movement (Tampa Scale of Kinesiophobia). Patients with juvenile FM demonstrated mild deficiencies in walking gait and functional performance (P < 0.05 for both) and significantly lower left knee extension and flexion strength (18-22% deficit) and bilateral hip abduction strength (34-38%) compared with healthy controls (P < 0.008 for all). Patients with juvenile FM reported significantly higher functional disability, pain intensity, depressive symptoms, and fear of movement relative to controls (P < 0.01 for all). This study showed that adolescents with juvenile FM exhibited objective alterations in biomechanics and self-reported fear of movement that may have reinforced their activity avoidance. Interventions for juvenile FM should include a focus on correcting functional deficits and instilling greater confidence in adolescents with juvenile FM to engage in exercise to improve functional outcomes. Copyright © 2015 by the American College of Rheumatology.

Innovative approaches to cell biomechanics from cell migration to on-chip manipulation

CERN Document Server

Okeyo, Kennedy Omondi; Adachi, Taiji

2015-01-01

This book covers topics on mechanosensing, mechanotransduction, and actin cytoskeletal dynamics in cell motility. It will contribute to a better understanding of how cells functionally adapt to their mechanical environment as well as highlighting fundamental concepts for designing material niches for cell manipulation. With topics from multidisciplinary fields of the life sciences, medicine, and engineering, the book is the first of its kind, providing comprehensive, integrated coverage of innovative approaches to cell biomechanics. It provides a valuable resource for seniors and graduate students studying cell biomechanics, and is also suitable for researchers interested in the application of methods and strategies in connection with the innovative approaches discussed. Each section of the book has been supplemented with concrete examples and illustrations to facilitate understanding even for readers unfamiliar with cell biomechanics.

Effects of total flavonoids from Drynariae Rhizoma prevent bone loss in vivo and in vitro

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Shuang-hong Song

2016-12-01

Full Text Available Estrogen deficiency is one of the major causes of osteoporosis in postmenopausal women. Drynariae Rhizoma is a widely used traditional Chinese medicine for the treatment of bone diseases. In this study, we investigated the therapeutic effects of the total Drynariae Rhizoma flavonoids (DRTF on estrogen deficiency-induced bone loss using an ovariectomized rat model and osteoblast-like MC3T3-E1 cells. Our results indicated that DRTF produced osteo-protective effects on the ovariectomized rats in terms of bone loss reduction, including decreased levels of bone turnover markers, enhanced biomechanical femur strength and trabecular bone microarchitecture deterioration prevention. In vitro experiments revealed that the actions of DRTF on regulating osteoblastic activities were mediated by the estrogen receptor (ER dependent pathway. Our data also demonstrated that DRTF inhibited osteoclastogenesis via up-regulating osteoprotegrin (OPG, as well as down-regulating receptor activator of NF–κB ligand (RANKL expression. In conclusion, this study indicated that DRTF treatment effectively suppressed bone mass loss in an ovariectomized rat model, and in vitro evidence suggested that the effects were exerted through actions on both osteoblasts and osteoclasts. Keywords: Osteoporosis, Osteoblast, Osteoclast, Ovariectomy, Drynariae Rhizoma

Biomechanical, anthropometric, and psychological determinants of barbell back squat strength.

Science.gov (United States)

Vigotsky, Andrew D; Bryanton, Megan A; Nuckols, Greg; Beardsley, Chris; Contreras, Bret; Evans, Jessica; Schoenfeld, Brad J

2018-02-27

Previous investigations of strength have only focused on biomechanical or psychological determinants, while ignoring the potential interplay and relative contributions of these variables. The purpose of this study was to investigate the relative contributions of biomechanical, anthropometric, and psychological variables to the prediction of maximum parallel barbell back squat strength. Twenty-one college-aged participants (male = 14; female = 7; age = 23 ± 3 years) reported to the laboratory for two visits. The first visit consisted of anthropometric, psychometric, and parallel barbell back squat one-repetition maximum (1RM) testing. On the second visit, participants performed isometric dynamometry testing for the knee, hip, and spinal extensors in a sticking point position-specific manner. Multiple linear regression and correlations were used to investigate the combined and individual relationships between biomechanical, anthropometric, and psychological variables and squat 1RM. Multiple regression revealed only one statistically predictive determinant: fat free mass normalized to height (standardized estimate ± SE = 0.6 ± 0.3; t(16) = 2.28; p = 0.037). Correlation coefficients for individual variables and squat 1RM ranged from r = -0.79-0.83, with biomechanical, anthropometric, experiential, and sex predictors showing the strongest relationships, and psychological variables displaying the weakest relationships. These data suggest that back squat strength in a heterogeneous population is multifactorial and more related to physical rather than psychological variables.

A biomechanical analysis of the vertebral and rib deformities in structural scoliosis

NARCIS (Netherlands)

Veldhuizen, AG; Klein, JP; Webb, PJ; Nijenbanning, G; Cool, JC; von Horn, [No Value

Although the structural changes occurring in the scoliotic spine have been reported as early as the 19th century, the descriptions and biomechanical explanations have not always been complete and consistent. In this study, three-dimensionally rendered CT images of two human skeletons with a

Biomechanical and psychosocial work exposures and musculoskeletal symptoms among vineyard workers.

Science.gov (United States)

Bernard, Christophe; Courouve, Laurène; Bouée, Stéphane; Adjémian, Annie; Chrétien, Jean-Claude; Niedhammer, Isabelle

2011-01-01

This study explored the associations between biomechanical and psychosocial work factors and musculoskeletal symptoms in vineyard workers. This cross-sectional study was based on a random sample of 2,824 male and 1,123 female vineyard workers in France. Data were collected using a self-administered questionnaire. Neck/shoulder, back and upper and lower extremity symptoms were evaluated using the Nordic questionnaire. Biomechanical exposures included 15 tasks related to vineyard activities. Psychosocial work factors included effort-reward imbalance and overcommitment, measured using the effort-reward imbalance model, and low job control and insufficient material means. Statistical analysis was performed using logistic regression analysis, and the results were adjusted for age, body mass index, educational level, work status and years in vineyard. Pruning-related factors increased the risk of upper extremity pain for both genders, of back pain for men and of neck/shoulder and lower extremity pain for women. Driving increased the risk of neck/shoulder and back pain among men. Psychosocial work factors, which were insufficient material means, overcommitment (both genders), effort-reward imbalance (men) and low job control (women), were associated with musculoskeletal symptoms, back and upper extremity pain for both genders and neck/shoulder and lower extremity pain for men. These results underlined that both biomechanical and psychosocial work factors may play a role in musculoskeletal pain among vineyard workers. Prevention policies focusing on both biomechanical and psychosocial work exposures may be useful to prevent musculoskeletal symptoms.

Biomechanical analysis on stent materials used as cardiovascular implants

Science.gov (United States)

Kumar, Vasantha; Ramesha, C. M.; Sajjan, Sudheer S.

2018-04-01

Atherosclerosis is the most common cause of death in the world, accounting for 48% of all deaths in the world. Atherosclerosis, also known as coronary artery disease occurs when excess cholesterol attaches itself to the walls of blood vessels. Coronary stent implantation is one of the most important procedures to treating coronary artery disease such atherosclerosis. Due to its efficiency, flexibility and simplicity, the use of coronary stents procedures has increased rapidly. In order to have better output of stent implantation, it is needed to study and analyze the biomechanical behavior of this device before manufacturing and put into use. Biomaterials are commonly used for medical application in cardiovascular stent implantation. A biomaterial is a non-viable material used as medical implant, so it is intended to interact with biological system. In this paper, an explicit dynamic analysis is used for analyzing the biomechanical behavior of cardiovascular stent by using finite element analysis tool, ABAQUS 6.10. Results showed that a best suitable biomaterial for cardiovascular stent implants, which exhibits an outstanding biocompatibility and biomechanical characteristics will be aimed at which will be quite useful to the human beings worldwide.

Future of crash dummies and biomechanical mathematical models

NARCIS (Netherlands)

Wismans, J.S.H.M.

2000-01-01

Thorough knowledge of the characteristics of the human body and its behaviour under extreme loading conditions is essential in order to prevent the serious consequences of road and other accidents. This field of research is called injury or impact biomechanics. In order to study the human body

Weightbath hydrotraction treatment: application, biomechanics, and clinical effects

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Márta Kurutz

2010-04-01

Full Text Available Márta Kurutz1, Tamás Bender21Department of Structural Mechanics, Budapest University of Technology and Economics, Hungary; 2Department of Physical Medicine, Polyclinic and Hospital of the Hospitaller Brothers of St. John of God, Budapest, Medical University of Szeged, HungaryBackground and purpose: Weightbath hydrotraction treatment (WHT is a simple noninvasive effective method of hydro- or balneotherapy to stretch the spine or lower limbs, applied successfully in hospitals and health resort sanitaria in Hungary for more than fifty years. This study aims to introduce WHT with its biomechanical and clinical effects. History, development, equipment, modes of application, biomechanics, spinal traction forces and elongations, indications and contraindications of WHT are precented.Subjects and methods: The calculation of traction forces acting along the spinal column during the treatment is described together with the mode of suspension and the position of extra weight loads applied. The biomechanics of the treatment are completed by in vivo measured elongations of lumbar segments using a special underwater ultrasound measuring method. The clinical effects, indications, and contraindications of the treatment are also presented.Results: In the underwater cervical suspension of a human body, approximately 25 N stretching load occurs in the cervical spine, and about 11 N occurs in the lumbar spine. By applying extra weights, the above tensile forces along the spinal column can be increased. Thus, the traction effect can be controlled by applying such loads during the treatment. Elongations of segments L3–L4, L4–L5, and L5–S1 were measured during the usual WHT of patients suspended cervically in water for 20 minutes, loaded by 20–20 N lead weights on the ankles. The mean initial elastic elongations of spinal segments were about 0.8 mm for patients aged under 40 years, 0.5 mm between 40–60 years, and 0.2 mm for patients over 60 years. The mean

The Biomechanics of Cervical Spondylosis

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Lisa A. Ferrara

2012-01-01

Full Text Available Aging is the major risk factor that contributes to the onset of cervical spondylosis. Several acute and chronic symptoms can occur that start with neck pain and may progress into cervical radiculopathy. Eventually, the degenerative cascade causes desiccation of the intervertebral disc resulting in height loss along the ventral margin of the cervical spine. This causes ventral angulation and eventual loss of lordosis, with compression of the neural and vascular structures. The altered posture of the cervical spine will progress into kyphosis and continue if the load balance and lordosis is not restored. The content of this paper will address the physiological and biomechanical pathways leading to cervical spondylosis and the biomechanical principles related to the surgical correction and treatment of kyphotic progression.

Analysis on Biomechanical Characteristics of Post-operational Vertebral C5-C6 Segments

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Heqiang Tian

2016-03-01

Full Text Available Both anterior cervical decompression and fusion (ACDF and artificial cervical disc replacement (ACDR have obvious advantages in the treatment of cervical spondylosis. To analyze the operation results, it is absolutely necessary to study the biomechanics of the movement range of post-operational vertebral C5-C6 segments, especially the biomechanical characteristics in cervical tissues in actual movements. In this study, using the human vertebral 3D graph gained by imaging diagnosis (CT, a vertebral solid model is established by the 3D reconstruction algorithm and reverse engineering technology. After that, with cervical soft tissue structure added to the solid model and set with a joint contact mechanism, a finite element model with a complete, accurate cervical C5-C6 kinematic unit is constructed, based on relevant physiological anatomical knowledge. This model includes vertebral segments, an intervertebral disc, ligament and zygopophysis in the cervical C5-C6 kinematic unit. In the created vertebral finite element model, the model is amended, referring to ACDF and ACDR, and the load and constraint are applied to a normal group, a fusion group and a displacement group, so as to analyze the biomechanical characteristics of the cervical vertebra after ACDF and ACDR. By comparing the finite element simulation results of different surgeries, this paper is intended to evaluate the functions and biomechanical behaviors of the post-operational vertebra, and explore the influence of the operation on the biomechanical stability of the cervical vertebra. This will provide theoretical guidance for implementation and optimization of ACDF and ACDR.

Augmentation of tendon healing with butyric acid-impregnated sutures: biomechanical evaluation in a rabbit model.

Science.gov (United States)

Leek, Bryan T; Tasto, James P; Tibor, Lisa M; Healey, Robert M; Freemont, Anthony; Linn, Michael S; Chase, Derek E; Amiel, David

2012-08-01

Butyric acid (BA) has been shown to be angiogenic and to enhance transcriptional activity in tissue. These properties of BA have the potential to augment biological healing of a repaired tendon. To evaluate this possibility both biomechanically and histologically in an animal tendon repair model. Controlled laboratory study. A rabbit Achilles tendon healing model was used to evaluate the biomechanical strength and histological properties at 6 and 12 weeks after repair. Unilateral tendon defects were created in the middle bundle of the Achilles tendon of each rabbit, which were repaired equivalently with either Ultrabraid BA-impregnated sutures or control Ultrabraid sutures. After 6 weeks, BA-impregnated suture repairs had a significantly increased (P Tendons repaired with BA-impregnated sutures demonstrated improved biomechanical properties at 6 weeks relative to control sutures, suggesting a neoangiogenic mechanism of enhanced healing through an increased myofibroblast presence. These findings demonstrate that a relatively simple alteration of suture material may augment early tendon healing to create a stronger repair construct during this time.

Biomechanical response of human spleen in tensile loading.

Science.gov (United States)

Kemper, Andrew R; Santago, Anthony C; Stitzel, Joel D; Sparks, Jessica L; Duma, Stefan M

2012-01-10

Blunt splenic injuries are most frequently caused as a result of motor vehicle collisions and are associated with high mortality rates. In order to accurately assess the risk of automotive related spleen injuries using tools such as finite element models, tissue level tolerance values and suitable material models must be developed and validated based on appropriate biomechanical data. This study presents a total of 41 tension tests performed on spleen parenchyma coupons and 29 tension tests performed on spleen capsule/parenchyma coupons. Standard dog-bone coupons were obtained from fresh human spleen and tested within 48 h of death. Each coupon was tested once to failure at one of the four loading rates to investigate the effects of rate dependence. Load and acceleration data were obtained at each of the specimen grips. High-speed video and optical markers placed on the specimens were used to measure local displacement. Failure stress and strain were calculated at the location of failure in the gage length of the coupon. The results of the study showed that both the spleen parenchyma and the capsule are rate dependent, with higher loading rates yielding higher failure stresses and lower failure strains. The results also show that the failure stress of the splenic capsule is significantly greater than that of the underlying parenchyma. Overall, this study provides novel biomechanical data that demonstrate the rate dependent tissue level tolerance values of human spleen tissue in tensile loading, which can aid in the improvement of finite element models used to assess injury risk in blunt trauma. Published by Elsevier Ltd.

The Relationship between Running Economy and Biomechanical Variables in Distance Runners

Science.gov (United States)

Tartaruga, Marcus Peikriszwili; Brisswalter, Jeanick; Peyre-Tartaruga, Leonardo Alexandre; Avila, Aluisio Otavio Vargas; Alberton, Cristine Lima; Coertjens, Marcelo; Cadore, Eduardo Lusa; Tiggemann, Carlos Leandro; Silva, Eduardo Marczwski; Kruel, Luiz Fernando Martins

2012-01-01

In this study, we analyzed the relationship between running economy (RE) and biomechanical parameters in a group running at the same relative intensity and same absolute velocity. Sixteen homogeneous male long-distance runners performed a test to determine RE at 4.4 m.s[superscript -1], corresponding to 11.1% below velocity at the ventilatory…

A literature review of the effects of computer input device design on biomechanical loading and musculoskeletal outcomes during computer work.

Science.gov (United States)

Bruno Garza, J L; Young, J G

2015-01-01

Extended use of conventional computer input devices is associated with negative musculoskeletal outcomes. While many alternative designs have been proposed, it is unclear whether these devices reduce biomechanical loading and musculoskeletal outcomes. To review studies describing and evaluating the biomechanical loading and musculoskeletal outcomes associated with conventional and alternative input devices. Included studies evaluated biomechanical loading and/or musculoskeletal outcomes of users' distal or proximal upper extremity regions associated with the operation of alternative input devices (pointing devices, mice, other devices) that could be used in a desktop personal computing environment during typical office work. Some alternative pointing device designs (e.g. rollerbar) were consistently associated with decreased biomechanical loading while other designs had inconsistent results across studies. Most alternative keyboards evaluated in the literature reduce biomechanical loading and musculoskeletal outcomes. Studies of other input devices (e.g. touchscreen and gestural controls) were rare, however, those reported to date indicate that these devices are currently unsuitable as replacements for traditional devices. Alternative input devices that reduce biomechanical loading may make better choices for preventing or alleviating musculoskeletal outcomes during computer use, however, it is unclear whether many existing designs are effective.

The Use of Wearable Inertial Motion Sensors in Human Lower Limb Biomechanics Studies: A Systematic Review

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Yue-Yan Chan

2010-12-01

Full Text Available Wearable motion sensors consisting of accelerometers, gyroscopes and magnetic sensors are readily available nowadays. The small size and low production costs of motion sensors make them a very good tool for human motions analysis. However, data processing and accuracy of the collected data are important issues for research purposes. In this paper, we aim to review the literature related to usage of inertial sensors in human lower limb biomechanics studies. A systematic search was done in the following search engines: ISI Web of Knowledge, Medline, SportDiscus and IEEE Xplore. Thirty nine full papers and conference abstracts with related topics were included in this review. The type of sensor involved, data collection methods, study design, validation methods and its applications were reviewed.

The use of wearable inertial motion sensors in human lower limb biomechanics studies: a systematic review.

Science.gov (United States)

Fong, Daniel Tik-Pui; Chan, Yue-Yan

2010-01-01

Wearable motion sensors consisting of accelerometers, gyroscopes and magnetic sensors are readily available nowadays. The small size and low production costs of motion sensors make them a very good tool for human motions analysis. However, data processing and accuracy of the collected data are important issues for research purposes. In this paper, we aim to review the literature related to usage of inertial sensors in human lower limb biomechanics studies. A systematic search was done in the following search engines: ISI Web of Knowledge, Medline, SportDiscus and IEEE Xplore. Thirty nine full papers and conference abstracts with related topics were included in this review. The type of sensor involved, data collection methods, study design, validation methods and its applications were reviewed.

Computational biomechanics for medicine new approaches and new applications

CERN Document Server

Miller, Karol; Wittek, Adam; Nielsen, Poul

2015-01-01

The Computational Biomechanics for Medicine titles provide an opportunity for specialists in computational biomechanics to present their latest methodologiesand advancements. Thisvolumecomprises twelve of the newest approaches and applications of computational biomechanics, from researchers in Australia, New Zealand, USA, France, Spain and Switzerland. Some of the interesting topics discussed are:real-time simulations; growth and remodelling of soft tissues; inverse and meshless solutions; medical image analysis; and patient-specific solid mechanics simulations. One of the greatest challenges facing the computational engineering community is to extend the success of computational mechanics to fields outside traditional engineering, in particular to biology, the biomedical sciences, and medicine. We hope the research presented within this book series will contribute to overcoming this grand challenge.

Biomechanical bases of rehabilitation of children with cerebral palsy

Science.gov (United States)

Davlet'yarova, K. V.; Korshunov, S. D.; Kapilevich, L. V.

2015-11-01

Biomechanical analysis and the study results of children's with cerebral palsy (CP) muscles bioelectrical activity while walking on a flat surface are represented. Increased flexion in the hip and shoulder joints and extension in the elbow joint in children with cerebral palsy were observed, with the movement of the lower limbs had less smooth character in comparison with the control group. Herewith, the oscillation amplitude was significantly increased, and the frequency in the m. gastrocnemius and m. lateralis was decreased. It was shown, that the dynamic stereotype of walking in children with cerebral palsy was characterized by excessive involvement of m. gastrocnemius and m.latissimus dorsi in locomotion. Thus, resulting biomechanical and bioelectrical parameters of walking should be considered in the rehabilitation programs development.

In vivo biological performance of a novel highly bioactive glass-ceramic (Biosilicate®): A biomechanical and histomorphometric study in rat tibial defects.

Science.gov (United States)

Granito, Renata N; Rennó, Ana Claudia; Ravagnani, Christian; Bossini, Paulo S; Mochiuti, Daniel; Jorgetti, Vanda; Driusso, Patricia; Peitl, Oscar; Zanotto, Edgar D; Parizotto, Nivaldo A; Oishi, Jorge

2011-04-01

This study aimed to investigate bone responses to a novel bioactive fully crystallized glass-ceramic of the quaternary system P(2)O(5)-Na(2)O-CaO-SiO(2) (Biosilicate®). Although a previous study demonstrated positive effects of Biosilicate® on in vitro bone-like matrix formation, its in vivo effect was not studied yet. Male Wistar rats (n = 40) with tibial defects were used. Four experimental groups were designed to compare this novel biomaterial with a gold standard bioactive material (Bioglass® 45S5), unfilled defects and intact controls. A three-point bending test was performed 20 days after the surgical procedure, as well as the histomorphometric analysis in two regions of interest: cortical bone and medullary canal where the particulate biomaterial was implanted. The biomechanical test revealed a significant increase in the maximum load at failure and stiffness in the Biosilicate® group (vs. control defects), whose values were similar to uninjured bones. There were no differences in the cortical bone parameters in groups with bone defects, but a great deal of woven bone was present surrounding Biosilicate® and Bioglass® 45S5 particulate. Although both bioactive materials supported significant higher bone formation; Biosilicate® was superior to Bioglass® 45S5 in some histomorphometric parameters (bone volume and number of osteoblasts). Regarding bone resorption, Biosilicate® group showed significant higher number of osteoclasts per unit of tissue area than defect and intact controls, despite of the non-significant difference in the osteoclastic surface as percentage of bone surface. This study reveals that the fully crystallized Biosilicate® has good bone-forming and bone-bonding properties. Copyright © 2011 Wiley Periodicals, Inc.

Biomechanical properties: effects of low-level laser therapy and Biosilicate® on tibial bone defects in osteopenic rats.

Science.gov (United States)

Fangel, Renan; Bossini, Paulo S; Renno, Ana Cláudia; Granito, Renata N; Wang, Charles C; Nonaka, Keico O; Driusso, Patricia; Parizotto, Nivaldo A; Oishi, Jorge

2014-12-30

The aim of this study was to investigate the effects of laser therapy and Biosilicate® on the biomechanical properties of bone callus in osteopenic rats. Fifty female Wistar rats were equally divided into 5 groups (n=10/group): osteopenic rats with intact tibiae (SC); osteopenic rats with unfilled and untreated tibial bone defects (OC); osteopenic rats whose bone defects were treated with Biosilicate® (B); osteopenic rats whose bone defects were treated with 830-nm laser, at 120 J/cm2 (L120) and osteopenic rats whose bone defects were treated with Biosilicate® and 830-nm laser, at 120 J/cm2 (BL120). Ovariectomy (OVX) was used to induce osteopenia. A non-critical bone defect was created on the tibia of the osteopenic animals 8 weeks after OVX. In Biosilicate® groups, bone defects were completely filled with the biomaterial. For the laser therapy, an 830-nm laser, 120 J/cm2 was used. On day 14 postsurgery, rats were euthanized, and tibiae were removed for biomechanical analysis. Maximal load and energy absorption were higher in groups B and BL120, according to the indentation test. Animals submitted to low-level laser therapy (LLLT) did not show any significant biomechanical improvement, but the association between Biosilicate® and LLLT was shown to be efficient to enhance callus biomechanical properties. Conversely, no differences were found between study groups in the bending test. Biosilicate® alone or in association with low level laser therapy improves biomechanical properties of tibial bone callus in osteopenic rats.

Biomechanical properties of a novel biodegradable magnesium-based interference screw

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Marco Ezechieli

2016-06-01

Full Text Available Magnesium-based interference screws may be an alternative in anterior/posterior cruciate ligament reconstruction. The well-known osteoconductive effects of biodegradable magnesium alloys may be useful. It was the purpose of this study to evaluate the biomechanical properties of a magnesium based interference screw and compare it to a standard implant. A MgYREZr-alloy interference screw and a standard implant (Milagro®; De Puy Mitek, Raynham, MA, USA were used for graft fixation. Specimens were placed into a tensile loading fixation of a servohydraulic testing machine. Biomechanical analysis included pretensioning of the constructs at 20 N for 1 min following cyclic pretensioning of 20 cycles between 20 and 60 N. Biomechanical elongation was evaluated with cyclic loading of 1000 cycles between 50 and 200 N at 0.5 Hz. Maximum load to failure was 511.3±66.5 N for the Milagro® screw and 529.0±63.3 N for magnesium-based screw (ns, P=0.57. Elongations after preload, during cyclical loading and during failure load were not different between the groups (ns, P>0.05. Stiffness was 121.1±13.8 N/mm for the magnesiumbased screw and 144.1±18.4 for the Milagro® screw (ns, P=0.32. MgYREZr alloy interference screws show comparable results in biomechanical testing to standard implants and may be an alternative for anterior cruciate reconstruction in the future.

Modelling and Analysis on Biomechanical Dynamic Characteristics of Knee Flexion Movement under Squatting

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Jianping Wang

2014-01-01

Full Text Available The model of three-dimensional (3D geometric knee was built, which included femoral-tibial, patellofemoral articulations and the bone and soft tissues. Dynamic finite element (FE model of knee was developed to simulate both the kinematics and the internal stresses during knee flexion. The biomechanical experimental system of knee was built to simulate knee squatting using cadaver knees. The flexion motion and dynamic contact characteristics of knee were analyzed, and verified by comparing with the data from in vitro experiment. The results showed that the established dynamic FE models of knee are capable of predicting kinematics and the contact stresses during flexion, and could be an efficient tool for the analysis of total knee replacement (TKR and knee prosthesis design.

The medical simulation markup language - simplifying the biomechanical modeling workflow.

Science.gov (United States)

Suwelack, Stefan; Stoll, Markus; Schalck, Sebastian; Schoch, Nicolai; Dillmann, Rüdiger; Bendl, Rolf; Heuveline, Vincent; Speidel, Stefanie

2014-01-01

Modeling and simulation of the human body by means of continuum mechanics has become an important tool in diagnostics, computer-assisted interventions and training. This modeling approach seeks to construct patient-specific biomechanical models from tomographic data. Usually many different tools such as segmentation and meshing algorithms are involved in this workflow. In this paper we present a generalized and flexible description for biomechanical models. The unique feature of the new modeling language is that it not only describes the final biomechanical simulation, but also the workflow how the biomechanical model is constructed from tomographic data. In this way, the MSML can act as a middleware between all tools used in the modeling pipeline. The MSML thus greatly facilitates the prototyping of medical simulation workflows for clinical and research purposes. In this paper, we not only detail the XML-based modeling scheme, but also present a concrete implementation. Different examples highlight the flexibility, robustness and ease-of-use of the approach.

Surgical options for lumbosacral fusion: biomechanical stability, advantage, disadvantage and affecting factors in selecting options.

Science.gov (United States)

Yoshihara, Hiroyuki

2014-07-01

Numerous surgical procedures and instrumentation techniques for lumbosacral fusion (LSF) have been developed. This is probably because of its high mechanical demand and unique anatomy. Surgical options include anterior column support (ACS) and posterior stabilization procedures. Biomechanical studies have been performed to verify the stability of those options. The options have their own advantage but also disadvantage aspects. This review article reports the surgical options for lumbosacral fusion, their biomechanical stability, advantages/disadvantages, and affecting factors in option selection. Review of literature. LSF has lots of options both for ACS and posterior stabilization procedures. Combination of posterior stabilization procedures is an option. Furthermore, combinations of ACS and posterior stabilization procedures are other options. It is difficult to make a recommendation or treatment algorithm of LSF from the current literature. However, it is important to know all aspects of the options and decision-making of surgical options for LSF needs to be tailored for each patient, considering factors such as biomechanical stress and osteoporosis.

Meshless methods in biomechanics bone tissue remodelling analysis

CERN Document Server

Belinha, Jorge

2014-01-01

This book presents the complete formulation of a new advanced discretization meshless technique: the Natural Neighbour Radial Point Interpolation Method (NNRPIM). In addition, two of the most popular meshless methods, the EFGM and the RPIM, are fully presented. Being a truly meshless method, the major advantages of the NNRPIM over the FEM, and other meshless methods, are the remeshing flexibility and the higher accuracy of the obtained variable field. Using the natural neighbour concept, the NNRPIM permits to determine organically the influence-domain, resembling the cellulae natural behaviour. This innovation permits the analysis of convex boundaries and extremely irregular meshes, which is an advantage in the biomechanical analysis, with no extra computational effort associated.   This volume shows how to extend the NNRPIM to the bone tissue remodelling analysis, expecting to contribute with new numerical tools and strategies in order to permit a more efficient numerical biomechanical analysis.

Assessment of Corneal Biomechanical Properties by CorVis ST in Patients with Dry Eye and in Healthy Subjects

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Qin Long

2015-01-01

Full Text Available Purpose. To investigate corneal biomechanical properties in patients with dry eye and in healthy subjects using Corneal Visualization Scheimpflug Technology (CorVis ST. Methods. Biomechanical parameters were measured using CorVis ST in 28 eyes of 28 patients with dry eye (dry eye group and 26 normal subjects (control group. The Schirmer I test value, tear film break-up time (TBUT, and corneal staining score (CSS were recorded for each eye. Biomechanical properties were compared between the two groups and bivariate correlation analysis was used to assess the relationship between biomechanical parameters and dry eye signs. Results. Only one of the ten biomechanical parameters was significantly different between the two groups. Patients in the dry eye group had significantly lower highest concavity time (HC-time (P=0.02 than the control group. Correlation analysis showed a significant negative correlation between HC-time and CSS with marginal P value (ρ=-0.39, P=0.04 in the dry eye group. Conclusions. The corneal biomechanical parameter of HC-time is reduced in dry eyes compared to normal eyes. There was also a very weak but significant negative correlation between HC-time and CSS in the dry eye group, indicating that ocular surface damage can give rise to a more compliant cornea in dry eyes.

Biomechanical Factors in Tibial Stress Fracture

Science.gov (United States)

2001-08-01

Relationship between Loading Rates and Tibial Accelerometry in Forefoot Strike Runners. Presented at the Annual American Society of Biomechanics Mtg...of the APTA, Seattle, WA, 2/99. McClay, IS, Williams, DS, and Manal, KT. Lower Extremity Mechanics of Runners with a Converted Forefoot Strike ...Management, Inc, 1998-1999 The Effect of Different Orthotic Devices on Lower Extremity Mechanics of Rearfoot and Forefoot Strikers, $3,500. Foot Management

Biomechanical and morphological multi-parameter photoacoustic endoscope for identification of early esophageal disease

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Jin, Dayang; Yang, Fen; Chen, Zhongjiang; Yang, Sihua; Xing, Da

2017-09-01

The combination of phase-sensitive photoacoustic (PA) imaging of tissue viscoelasticity with the esophagus-adaptive PA endoscope (PAE) technique allows the characterization of the biomechanical and morphological changes in the early stage of esophageal disease with high accuracy. In this system, the tissue biomechanics and morphology are obtained by detecting the PA phase and PA amplitude information, respectively. The PAE has a transverse resolution of approximately 37 μm and an outer diameter of 1.2 mm, which is suitable for detecting rabbit esophagus. Here, an in-situ biomechanical and morphological study of normal and diseased rabbit esophagus (tumors of esophagus and reflux esophagitis) was performed. The in-situ findings were highly consistent with those observed by histology. In summary, we demonstrated the potential application of PAE for early clinical detection of esophageal diseases.

Analysis of Biomechanical Structure and Passing Techniques in Basketball

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Ricardo E. Izzo

2011-06-01

Full Text Available The basketball is a complex sport, which these days has become increasingly linked to its’ psychophysical aspects rather than to the technical ones. Therefore, it is important to make a through study of the passing techniques from the point of view of the type of the pass and its’ biomechanics. From the point of view of the type of the used passes, the most used is the two-handed chest pass with a frequency of 39.9%. This is followed, in terms of frequency, by one-handed passes – the baseball, with 20.9 % – and by the two-handed over the head pass, with 18.2 %, and finally, one- or two-handed indirect passes (bounces, with 11.2 % and 9.8 %. Considering the most used pass in basketball, from the biomechanical point of view, the muscles involved in the correct movement consider all the muscles of the upper extremity, adding also the shoulder muscles as well as the body fixators (abdominals, hip flexors, knee extensors, and dorsal flexors of the foot. The technical and conditional analysis considers the throwing speed, the throw height and the air resistance. In conclusion, the aim of this study is to give some guidelines to improve the mechanical execution of the movements in training, without neglecting the importance of the harmony of the movements themselves.

Biomechanical and structural parameters of tendons in rats subjected to swimming exercise.

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Bezerra, M A; Santos de Lira, K D; Coutinho, M P G; de Mesquita, G N; Novaes, K A; da Silva, R T B; de Brito Nascimento, A K; Inácio Teixeira, M F H B; Moraes, S R A

2013-12-01

The aim of this study was to evaluate the effect of swimming exercise, without overloading, on the biomechanical parameters of the calcaneal tendon of rats. 27 male Wistar rats (70 days) were distributed randomly into 2 groups, Control Group (CG; n=15) with restricted movements inside the cage and Swimming Group (SG; n=12), subjected to exercise training in a tank with a water temperature of 30±1°C, for 1 h/day, 5 days/week for 8 weeks. All animals were kept in a reversed light/dark cycle of 12 h with access to food and water ad libitum. After that, they were anesthetized and had their calcaneus tendons collected from their left rear paws. The tendon was submitted to a mechanical test on a conventional test machine. From the stress vs. strain curve, the biomechanical data were analyzed. For the statistical analysis, the Student-T test was used (penergy of deformation/tendon cross sectional area (p=0.017) and elastic modulus of the tendon (p=0.013) showed positive outcomes in SG. There was no difference in the other parameters. The results indicate that the swimming exercise training, without overloading, was an important stimulus for improving the biomechanical parameters and structural properties of the calcaneal tendon. © Georg Thieme Verlag KG Stuttgart · New York.

Initial stress in biomechanical models of atherosclerotic plaques

NARCIS (Netherlands)

Speelman, L.; Akyildiz, A.C.; Adel, den B.; Wentzel, J.J.; Steen, van der A.F.W.; Virmani, R.; Weerd, van der L.; Jukema, J.W.; Poelmann, R.E.; Brummelen, van E.H.; Gijsen, F.J.H.

2011-01-01

Rupture of atherosclerotic plaques is the underlying cause for the majority of acute strokes and myocardial infarctions. Rupture of the plaque occurs when the stress in the plaque exceeds the strength of the material locally. Biomechanical stress analyses are commonly based on pressurized

Properties of an interspinous fixation device (ISD) in lumbar fusion constructs: a biomechanical study.

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Techy, Fernando; Mageswaran, Prasath; Colbrunn, Robb W; Bonner, Tara F; McLain, Robert F

2013-05-01

Segmental fixation improves fusion rates and promotes patient mobility by controlling instability after lumbar surgery. Efforts to obtain stability using less invasive techniques have lead to the advent of new implants and constructs. A new interspinous fixation device (ISD) has been introduced as a minimally invasive method of stabilizing two adjacent interspinous processes by augmenting an interbody cage in transforaminal interbody fusion. The ISD is intended to replace the standard pedicle screw instrumentation used for posterior fixation. The purpose of this study is to compare the rigidity of these implant systems when supplementing an interbody cage as used in transforaminal lumbar interbody fusion. An in vitro human cadaveric biomechanical study. Seven human cadaver spines (T12 to the sacrum) were mounted in a custom-designed testing apparatus, for biomechanical testing using a multiaxial robotic system. A comparison of segmental stiffness was carried out among five conditions: intact spine control; interbody spacer (IBS), alone; interbody cage with ISD; IBS, ISD, and unilateral pedicle screws (unilat); and IBS, with bilateral pedicle screws (bilat). An industrial robot (KUKA, GmbH, Augsburg, Germany) applied a pure moment (±5 Nm) in flexion-extension (FE), lateral bending (LB), and axial rotation (AR) through an anchor to the T12 vertebral body. The relative vertebral motion was captured using an optoelectronic camera system (Optotrak; Northern Digital, Inc., Waterloo, Ontario, Canada). The load sensor and the camera were synchronized. Maximum rotation was measured at each level and compared with the intact control. Implant constructs were compared with the control and with each other. A statistical analysis was performed using analysis of variance. A comparison between the intact spine and the IBS group showed no significant difference in the range of motion (ROM) in FE, LB, or AR for the operated level, L3-L4. After implantation of the ISD to augment

[The development of an oral biomechanical testing instrument].

Science.gov (United States)

Zhang, X H; Sun, X D; Lin, Z

2000-03-01

An oral biomechanical testing instrument, which is portable, powered with batteries and controlled by single chip microcomputer, was described. The instrument was characterized by its multichannel, high accuracy, low power dissipation, wide rage of force measurement and stable performance. It can be used for acquisiting, displaying and storing data. And it may be expected to be an ideal instrument for oral biomechanical measurements.

The Value of Biomechanical Research in Dance.

Science.gov (United States)

Ranney, D. A.

Simple observation of dance movement, while very useful, can lead to misconceptions, about the physical realities of dance movement, that make learning difficult. This gap between reality and understanding can be reduced by the application of biomechanical techniques such as cinematography, electromyography, and force-plate analysis. Biomechanical…

An introduction to biomechanics solids and fluids, analysis and design

CERN Document Server

Humphrey, Jay D

2004-01-01

Designed to meet the needs of undergraduate students, Introduction to Biomechanics takes the fresh approach of combining the viewpoints of both a well-respected teacher and a successful student. With an eye toward practicality without loss of depth of instruction, this book seeks to explain the fundamental concepts of biomechanics. With the accompanying web site providing models, sample problems, review questions and more, Introduction to Biomechanics provides students with the full range of instructional material for this complex and dynamic field.

Biomechanical paradigm and interpretation of female pelvic floor conditions before a treatment

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Lucente V

2017-08-01

Full Text Available Vincent Lucente,1 Heather van Raalte,2 Miles Murphy,1 Vladimir Egorov3 1The Institute for Female Pelvic Medicine and Reconstructive Surgery, Allentown, PA, USA; 2Princeton Urogynecology, Princeton, NJ, USA; 3Artann Laboratories, Trenton, NJ, USA Background: Further progress in restoring a woman’s health may be possible if a patient with a damaged pelvic floor could undergo medical imaging and biomechanical diagnostic tests. The results of such tests could contribute to the analysis of multiple treatment options and suggest the optimal one for that patient.Aim: To develop a new approach for the biomechanical characterization of vaginal conditions, muscles, and connective tissues in the female pelvic floor.Methods: Vaginal tactile imaging (VTI allows biomechanical assessment of the soft tissue along the entire length of the anterior, posterior, and lateral vaginal walls at rest, with manually applied deflection pressures and with muscle contraction, muscle relaxation, and Valsalva maneuver. VTI allows a large body of measurements to evaluate individual variations in tissue elasticity, support defects, as well as pelvic muscle function. Presuming that 1 the female pelvic floor organs are suspended by ligaments against which muscles contract to open or close the outlets and 2 damaged ligaments weaken the support and may reduce the force of muscle contraction, we made an attempt to characterize multiple pelvic floor structures from VTI data.Results: All of the 138 women enrolled in the study were successfully examined with the VTI. The study subjects have had normal pelvic support or pelvic organ prolapse (stages I–IV. The average age of this group of subjects was 60±15 years. We transposed a set of 31 VTI parameters into a quantitative characterization of pelvic muscles and ligamentous structures. Interpretation of the acquired VTI data for normal pelvic floor support and prolapse conditions is proposed based on biomechanical assessment of the

Surface-based prostate registration with biomechanical regularization

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van de Ven, Wendy J. M.; Hu, Yipeng; Barentsz, Jelle O.; Karssemeijer, Nico; Barratt, Dean; Huisman, Henkjan J.

2013-03-01

Adding MR-derived information to standard transrectal ultrasound (TRUS) images for guiding prostate biopsy is of substantial clinical interest. A tumor visible on MR images can be projected on ultrasound by using MRUS registration. A common approach is to use surface-based registration. We hypothesize that biomechanical modeling will better control deformation inside the prostate than a regular surface-based registration method. We developed a novel method by extending a surface-based registration with finite element (FE) simulation to better predict internal deformation of the prostate. For each of six patients, a tetrahedral mesh was constructed from the manual prostate segmentation. Next, the internal prostate deformation was simulated using the derived radial surface displacement as boundary condition. The deformation field within the gland was calculated using the predicted FE node displacements and thin-plate spline interpolation. We tested our method on MR guided MR biopsy imaging data, as landmarks can easily be identified on MR images. For evaluation of the registration accuracy we used 45 anatomical landmarks located in all regions of the prostate. Our results show that the median target registration error of a surface-based registration with biomechanical regularization is 1.88 mm, which is significantly different from 2.61 mm without biomechanical regularization. We can conclude that biomechanical FE modeling has the potential to improve the accuracy of multimodal prostate registration when comparing it to regular surface-based registration.

Biomechanical force induces the growth factor production in human periodontal ligament-derived cells.

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Ichioka, Hiroaki; Yamamoto, Toshiro; Yamamoto, Kenta; Honjo, Ken-Ichi; Adachi, Tetsuya; Oseko, Fumishige; Mazda, Osam; Kanamura, Narisato; Kita, Masakazu

2016-01-01

Although many reports have been published on the functional roles of periodontal ligament (PDL) cells, the mechanisms involved in the maintenance and homeostasis of PDL have not been determined. We investigated the effects of biomechanical force on growth factor production, phosphorylation of MAPKs, and intracellular transduction pathways for growth factor production in human periodontal ligament (hPDL) cells using MAPK inhibitors. hPDL cells were exposed to mechanical force (6 MPa) using a hydrostatic pressure apparatus. The levels of growth factor mRNA and protein were examined by real-time RT-PCR and ELISA. The phosphorylation of MAPKs was measured using BD™ CBA Flex Set. In addition, MAPKs inhibitors were used to identify specific signal transduction pathways. Application of biomechanical force (equivalent to occlusal force) increased the synthesis of VEGF-A, FGF-2, and NGF. The application of biomechanical force increased the expression levels of phosphorylated ERK and p38, but not of JNK. Furthermore, the levels of VEGF-A and NGF expression were suppressed by ERK or p38 inhibitor. The growth factors induced by biomechanical force may play a role in the mechanisms of homeostasis of PDL.

Platelet biomechanics, platelet bioenergetics, and applications to clinical practice and translational research.

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George, Mitchell J; Bynum, James; Nair, Prajeeda; Cap, Andrew P; Wade, Charles E; Cox, Charles S; Gill, Brijesh S

2018-07-01

The purpose of this review is to explore the relationship between platelet bioenergetics and biomechanics and how this relationship affects the clinical interpretation of platelet function devices. Recent experimental and technological advances highlight platelet bioenergetics and biomechanics as alternative avenues for collecting clinically relevant data. Platelet bioenergetics drive energy production for key biomechanical processes like adhesion, spreading, aggregation, and contraction. Platelet function devices like thromboelastography, thromboelastometry, and aggregometry measure these biomechanical processes. Platelet storage, stroke, sepsis, trauma, or the activity of antiplatelet drugs alters measures of platelet function. However, the specific mechanisms governing these alterations in platelet function and how they relate to platelet bioenergetics are still under investigation.

Lateral Augmentation Procedures in Anterior Cruciate Ligament Reconstruction: Anatomic, Biomechanical, Imaging, and Clinical Evidence.

Science.gov (United States)

Weber, Alexander E; Zuke, William; Mayer, Erik N; Forsythe, Brian; Getgood, Alan; Verma, Nikhil N; Bach, Bernard R; Bedi, Asheesh; Cole, Brian J

2018-02-01

There has been an increasing interest in lateral-based soft tissue reconstructive techniques as augments to anterior cruciate ligament reconstruction (ACLR). The objective of these procedures is to minimize anterolateral rotational instability of the knee after surgery. Despite the relatively rapid increase in surgical application of these techniques, many clinical questions remain. To provide a comprehensive update on the current state of these lateral-based augmentation procedures by reviewing the origins of the surgical techniques, the biomechanical data to support their use, and the clinical results to date. Systematic review. A systematic search of the literature was conducted via the Medline, EMBASE, Scopus, SportDiscus, and CINAHL databases. The search was designed to encompass the literature on lateral extra-articular tenodesis (LET) procedures and the anterolateral ligament (ALL) reconstruction. Titles and abstracts were reviewed for relevance and sorted into the following categories: anatomy, biomechanics, imaging/diagnostics, surgical techniques, and clinical outcomes. The search identified 4016 articles. After review for relevance, 31, 53, 27, 35, 45, and 78 articles described the anatomy, biomechanics, imaging/diagnostics, surgical techniques, and clinical outcomes of either LET procedures or the ALL reconstruction, respectively. A multitude of investigations were available, revealing controversy in addition to consensus in several categories. The level of evidence obtained from this search was not adequate for systematic review or meta-analysis; thus, a current concepts review of the anatomy, biomechanics, imaging, surgical techniques, and clinical outcomes was performed. Histologically, the ALL appears to be a distinct structure that can be identified with advanced imaging techniques. Biomechanical evidence suggests that the anterolateral structures of the knee, including the ALL, contribute to minimizing anterolateral rotational instability

CT-derived Biomechanical Metrics Improve Agreement Between Spirometry and Emphysema

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Bhatt, Surya P.; Bodduluri, Sandeep; Newell, John D.; Hoffman, Eric A.; Sieren, Jessica C.; Han, Meilan K.; Dransfield, Mark T.; Reinhardt, Joseph M.

2016-01-01

Rationale and Objectives Many COPD patients have marked discordance between FEV1 and degree of emphysema on CT. Biomechanical differences between these patients have not been studied. We aimed to identify reasons for the discordance between CT and spirometry in some patients with COPD. Materials and Methods Subjects with GOLD stage I–IV from a large multicenter study (COPDGene) were arranged by percentiles of %predicted FEV1 and emphysema on CT. Three categories were created using differences in percentiles: Catspir with predominant airflow obstruction/minimal emphysema, CatCT with predominant emphysema/minimal airflow obstruction, and Catmatched with matched FEV1 and emphysema. Image registration was used to derive Jacobian determinants, a measure of lung elasticity, anisotropy and strain tensors, to assess biomechanical differences between groups. Regression models were created with the above categories as outcome variable, adjusting for demographics, scanner type, quantitative CT-derived emphysema, gas trapping, and airway thickness (Model 1), and after adding biomechanical CT metrics (Model 2). Results Jacobian determinants, anisotropy and strain tensors were strongly associated with FEV1. With Catmatched as control, Model 2 predicted Catspir and CatCT better than Model 1 (Akaike Information Criterion, AIC 255.8 vs. 320.8). In addition to demographics, the strongest independent predictors of FEV1 were Jacobian mean (β= 1.60,95%CI = 1.16 to 1.98; p<0.001), coefficient of variation (CV) of Jacobian (β= 1.45,95%CI = 0.86 to 2.03; p<0.001) and CV strain (β= 1.82,95%CI = 0.68 to 2.95; p = 0.001). CVs of Jacobian and strain are both potential markers of biomechanical lung heterogeneity. Conclusions CT-derived measures of lung mechanics improve the link between quantitative CT and spirometry, offering the potential for new insights into the linkage between regional parenchymal destruction and global decrement in lung function in COPD patients. PMID:27055745

Are cranial biomechanical simulation data linked to known diets in extant taxa? A method for applying diet-biomechanics linkage models to infer feeding capability of extinct species.

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Zhijie Jack Tseng

Full Text Available Performance of the masticatory system directly influences feeding and survival, so adaptive hypotheses often are proposed to explain craniodental evolution via functional morphology changes. However, the prevalence of "many-to-one" association of cranial forms and functions in vertebrates suggests a complex interplay of ecological and evolutionary histories, resulting in redundant morphology-diet linkages. Here we examine the link between cranial biomechanical properties for taxa with different dietary preferences in crown clade Carnivora, the most diverse clade of carnivorous mammals. We test whether hypercarnivores and generalists can be distinguished based on cranial mechanical simulation models, and how such diet-biomechanics linkages relate to morphology. Comparative finite element and geometric morphometrics analyses document that predicted bite force is positively allometric relative to skull strain energy; this is achieved in part by increased stiffness in larger skull models and shape changes that resist deformation and displacement. Size-standardized strain energy levels do not reflect feeding preferences; instead, caniform models have higher strain energy than feliform models. This caniform-feliform split is reinforced by a sensitivity analysis using published models for six additional taxa. Nevertheless, combined bite force-strain energy curves distinguish hypercarnivorous versus generalist feeders. These findings indicate that the link between cranial biomechanical properties and carnivoran feeding preference can be clearly defined and characterized, despite phylogenetic and allometric effects. Application of this diet-biomechanics linkage model to an analysis of an extinct stem carnivoramorphan and an outgroup creodont species provides biomechanical evidence for the evolution of taxa into distinct hypercarnivorous and generalist feeding styles prior to the appearance of crown carnivoran clades with similar feeding preferences.

First Reported Cases of Biomechanically Adaptive Bone Modeling in Non-Avian Dinosaurs.

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Jorge Cubo

Full Text Available Predator confrontation or predator evasion frequently produces bone fractures in potential prey in the wild. Although there are reports of healed bone injuries and pathologies in non-avian dinosaurs, no previously published instances of biomechanically adaptive bone modeling exist. Two tibiae from an ontogenetic sample of fifty specimens of the herbivorous dinosaur Maiasaura peeblesorum (Ornithopoda: Hadrosaurinae exhibit exostoses. We show that these outgrowths are cases of biomechanically adaptive periosteal bone modeling resulting from overstrain on the tibia after a fibula fracture. Histological and biomechanical results are congruent with predictions derived from this hypothesis. Histologically, the outgrowths are constituted by radial fibrolamellar periosteal bone tissue formed at very high growth rates, as expected in a process of rapid strain equilibration response. These outgrowths show greater compactness at the periphery, where tensile and compressive biomechanical constraints are higher. Moreover, these outgrowths increase the maximum bending strength in the direction of the stresses derived from locomotion. They are located on the antero-lateral side of the tibia, as expected in a presumably bipedal one year old individual, and in the posterior position of the tibia, as expected in a presumably quadrupedal individual at least four years of age. These results reinforce myological evidence suggesting that Maiasaura underwent an ontogenetic shift from the primitive ornithischian bipedal condition when young to a derived quadrupedal posture when older.

First Reported Cases of Biomechanically Adaptive Bone Modeling in Non-Avian Dinosaurs.

Science.gov (United States)

Cubo, Jorge; Woodward, Holly; Wolff, Ewan; Horner, John R

2015-01-01

Predator confrontation or predator evasion frequently produces bone fractures in potential prey in the wild. Although there are reports of healed bone injuries and pathologies in non-avian dinosaurs, no previously published instances of biomechanically adaptive bone modeling exist. Two tibiae from an ontogenetic sample of fifty specimens of the herbivorous dinosaur Maiasaura peeblesorum (Ornithopoda: Hadrosaurinae) exhibit exostoses. We show that these outgrowths are cases of biomechanically adaptive periosteal bone modeling resulting from overstrain on the tibia after a fibula fracture. Histological and biomechanical results are congruent with predictions derived from this hypothesis. Histologically, the outgrowths are constituted by radial fibrolamellar periosteal bone tissue formed at very high growth rates, as expected in a process of rapid strain equilibration response. These outgrowths show greater compactness at the periphery, where tensile and compressive biomechanical constraints are higher. Moreover, these outgrowths increase the maximum bending strength in the direction of the stresses derived from locomotion. They are located on the antero-lateral side of the tibia, as expected in a presumably bipedal one year old individual, and in the posterior position of the tibia, as expected in a presumably quadrupedal individual at least four years of age. These results reinforce myological evidence suggesting that Maiasaura underwent an ontogenetic shift from the primitive ornithischian bipedal condition when young to a derived quadrupedal posture when older.

[Advances on biomechanics and kinematics of sprain of ankle joint].

Science.gov (United States)

Zhao, Yong; Wang, Gang

2015-04-01

Ankle sprains are orthopedic clinical common disease, accounting for joint ligament sprain of the first place. If treatment is not timely or appropriate, the joint pain and instability maybe develop, and even bone arthritis maybe develop. The mechanism of injury of ankle joint, anatomical basis has been fully study at present, and the diagnostic problem is very clear. Along with the development of science and technology, biological modeling and three-dimensional finite element, three-dimensional motion capture system,digital technology study, electromyographic signal study were used for the basic research of sprain of ankle. Biomechanical and kinematic study of ankle sprain has received adequate attention, combined with the mechanism research of ankle sprain,and to explore the the biomechanics and kinematics research progress of the sprain of ankle joint.

Cement augmentation of implants--no general cure in osteoporotic fracture treatment. A biomechanical study on non-displaced femoral neck fractures.

Science.gov (United States)

Hofmann-Fliri, Ladina; Nicolino, Tomas I; Barla, Jorge; Gueorguiev, Boyko; Richards, R Geoff; Blauth, Michael; Windolf, Markus

2016-02-01

Femoral neck fractures in the elderly are a common problem in orthopedics. Augmentation of screw fixation with bone cement can provide better stability of implants and lower the risk of secondary displacement. This study aimed to investigate whether cement augmentation of three cannulated screws in non-displaced femoral neck fractures could increase implant fixation. A femoral neck fracture was simulated in six paired human cadaveric femora and stabilized with three 7.3 mm cannulated screws. Pairs were divided into two groups: conventional instrumentation versus additional cement augmentation of screw tips with 2 ml TraumacemV+ each. Biomechanical testing was performed by applying cyclic axial load until failure. Failure cycles, axial head displacement, screw angle changes, telescoping and screw cut-out were evaluated. Failure (15 mm actuator displacement) occurred in the augmented group at 12,500 cycles (± 2,480) compared to 15,625 cycles (± 4,215) in the non-augmented group (p = 0.041). When comparing 3 mm vertical displacement of the head no significant difference (p = 0.72) was detected between the survival curves of the two groups. At 8,500 load-cycles (early onset failure) the augmented group demonstrated a change in screw angle of 2.85° (± 0.84) compared to 1.15° (± 0.93) in the non-augmented group (p = 0.013). The results showed no biomechanical advantage with respect to secondary displacement following augmentation of three cannulated screws in a non-displaced femoral neck fracture. Consequently, the indication for cement augmentation to enhance implant anchorage in osteoporotic bone has to be considered carefully taking into account fracture type, implant selection and biomechanical surrounding. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Comparative analysis of poly-glycolic acid-based hybrid polymer starter matrices for in vitro tissue engineering.

Science.gov (United States)

Generali, Melanie; Kehl, Debora; Capulli, Andrew K; Parker, Kevin K; Hoerstrup, Simon P; Weber, Benedikt

2017-10-01

Biodegradable scaffold matrixes form the basis of any in vitro tissue engineering approach by acting as a temporary matrix for cell proliferation and extracellular matrix deposition until the scaffold is replaced by neo-tissue. In this context several synthetic polymers have been investigated, however a concise systematic comparative analyses is missing. Therefore, the present study systematically compares three frequently used polymers for the in vitro engineering of extracellular matrix based on poly-glycolic acid (PGA) under static as well as dynamic conditions. Ultra-structural analysis was used to examine the polymers structure. For tissue engineering (TE) three human fibroblast cell lines were seeded on either PGA-poly-4-hydroxybutyrate (P4HB), PGA-poly-lactic acid (PLA) or PGA-poly-caprolactone (PCL) patches. These patches were analyzed after 21days of culture qualitative by histology and quantitative by determining the amount of DNA, glycosaminoglycan and hydroxyproline. We found that PGA-P4HB and PGA-PLA scaffolds enhance tissue formation significantly higher than PGA-PCL scaffolds (p<0.05). Polymer remnants were visualized by polarization microscopy. In addition, biomechanical properties of the tissue engineered patches were determined in comparison to native tissue. This study may allow future studies to specifically select certain polymer starter matrices aiming at specific tissue properties of the bioengineered constructs in vitro. Copyright © 2017 Elsevier B.V. All rights reserved.

Biomechanical analysis of clavicle hook plate implantation with different hook angles in the acromioclavicular joint.

Science.gov (United States)

Hung, Li-Kun; Su, Kuo-Chih; Lu, Wen-Hsien; Lee, Cheng-Hung

2017-08-01

A clavicle hook plate is a simple and effective method for treating acromioclavicular dislocation and distal clavicle fractures. However, subacromial osteolysis and peri-implant fractures are complicated for surgeons to manage. This study uses finite element analysis (FEA) to investigate the post-implantation biomechanics of clavicle hook plates with different hook angles. This FEA study constructed a model with a clavicle, acromion, clavicle hook plate, and screws to simulate the implantation of clavicle hook plates at different hook angles (90°, 95°, 100°, 105°, and 110°) for treating acromioclavicular joint dislocations. This study investigated the biomechanics of the acromion, clavicle, hook plate, and screws. A smaller hook angle increases the stress on the middle third of the clavicle. A larger hook angle increases the force exerted by the clavicle hook plate on the acromion. The screw at the most medial position on the plate generated the highest stress. The highest stress on the implanted clavicle hook plate was on the turning corner of the hook. A clavicle hook plate with different hook angles may induce different biomechanical behaviors in the clavicle and acromion. Orthopedic surgeons must select a suitable clavicle hook plate based on the anatomical structure of each patient.

Evidence of Big Five and Aggressive Personalities in Gait Biomechanics

OpenAIRE

Satchell, Liam; Morris, Paul; Mills, Chris; O?Reilly, Liam; Marshman, Paul; Akehurst, Lucy

2016-01-01

Behavioral observation techniques which relate action to personality have long been neglected (Furr and Funder in Handbook of research methods in personality psychology, The Guilford Press, New York, 2007) and, when employed, often use human judges to code behavior. In the current study we used an alternative to human coding (biomechanical research techniques) to investigate how personality traits are manifest in gait. We used motion capture technology to record 29 participants walking on a t...

A biomechanical analysis of common lunge tasks in badminton.

Science.gov (United States)

Kuntze, Gregor; Mansfield, Neil; Sellers, William

2010-01-01

The lunge is regularly used in badminton and is recognized for the high physical demands it places on the lower limbs. Despite its common occurrence, little information is available on the biomechanics of lunging in the singles game. A video-based pilot study confirmed the relatively high frequency of lunging, approximately 15% of all movements, in competitive singles games. The biomechanics and performance characteristics of three badminton-specific lunge tasks (kick, step-in, and hop lunge) were investigated in the laboratory with nine experienced male badminton players. Ground reaction forces and kinematic data were collected and lower limb joint kinetics calculated using an inverse dynamics approach. The step-in lunge was characterized by significantly lower mean horizontal reaction force at drive-off and lower mean peak hip joint power than the kick lunge. The hop lunge resulted in significantly larger mean reaction forces during loading and drive-off phases, as well as significantly larger mean peak ankle joint moments and knee and ankle joint powers than the kick or step-in lunges. These findings indicate that, within the setting of this investigation, the step-in lunge may be beneficial for reducing the muscular demands of lunge recovery and that the hop lunge allows for higher positive power output, thereby presenting an efficient lunging method.

Are trichomes involved in the biomechanical systems of Cucurbita leaf petioles?

Science.gov (United States)

Zajączkowska, Urszula; Kucharski, Stanisław; Guzek, Dominika

2015-12-01

Trichomes are involved in petiole movement and likely function as a part of the plant biomechanical system serving as an additional reservoir of hydrostatic pressure. The large, non-glandular trichomes on Cucurbita petioles occur across collenchyma strands. Time-lapse imaging was used to study the leaf reorientation of Cucurbita maxima 'Bambino' plants placed in horizontal position. The experiment comprised four variants of the large non-glandular petiole trichomes: (1) intact, (2) mechanically removed, (3) dehydrated, and (4) intact but with longitudinally injured petioles. Isolated strands of collenchyma with intact epidermis or epidermis mechanically removed from the abaxial and adaxial sides of the petiole were subjected to breaking test. The stiffness of the non-isolated tissue with intact epidermis was measured using the micro-indentation method. Petioles without trichomes did not exhibit tropic response, and the dehydration of trichomes slowed and prevented complete leaf reorientation. Isolated strands of collenchyma showed no correlation between strength values and position on the petiole. However, strands of collenchyma with epidermis exhibited a significantly greater strength regardless of their position on the petiole. The indentation test showed that non-isolated collenchyma is stiffer on the abaxial side of the petiole. Trichomes from the abaxial side of the petiole were larger at their base. The application of the 'tensile triangles method' revealed that these trichomes had a biomechanically optimized shape in comparison to the adaxial side. We conclude that trichomes can be involved in plant biomechanical system and serve as an additional reservoir of hydrostatic pressure that is necessary for maintaining petioles in the prestressed state.

A motor learning approach to training wheelchair propulsion biomechanics for new manual wheelchair users: A pilot study.

Science.gov (United States)

Morgan, Kerri A; Tucker, Susan M; Klaesner, Joseph W; Engsberg, Jack R

2017-05-01

Developing an evidence-based approach to teaching wheelchair skills and proper propulsion for everyday wheelchair users with a spinal cord injury (SCI) is important to their rehabilitation. The purpose of this project was to pilot test manual wheelchair training based on motor learning and repetition-based approaches for new manual wheelchair users with an SCI. A repeated measures within-subject design was used with participants acting as their own controls. Six persons with an SCI requiring the use of a manual wheelchair participated in wheelchair training. The training included nine 90-minute sessions. The primary focus was on wheelchair propulsion biomechanics with a secondary focus on wheelchair skills. During Pretest 1, Pretest 2, and Posttest, wheelchair propulsion biomechanics were measured using the Wheelchair Propulsion Test and a Video Motion Capture system. During Pretest 2 and Posttest, propulsion forces using the WheelMill System and wheelchair skills using the Wheelchair Skills Test were measured. Significant changes in area of the push loop, hand-to-axle relationship, and slope of push forces were found. Changes in propulsion patterns were identified post-training. No significant differences were found in peak and average push forces and wheelchair skills pre- and post-training. This project identified trends in change related to a repetition-based motor learning approach for propelling a manual wheelchair. The changes found were related to the propulsion patterns used by participants. Despite some challenges associated with implementing interventions for new manual wheelchair users, such as recruitment, the results of this study show that repetition-based training can improve biomechanics and propulsion patterns for new manual wheelchair users.

Clinical applications of biomechanics cinematography.

Science.gov (United States)

Woodle, A S

1986-10-01

Biomechanics cinematography is the analysis of movement of living organisms through the use of cameras, image projection systems, electronic digitizers, and computers. This article is a comparison of cinematographic systems and details practical uses of the modality in research and education.

Study of osteoporosis through the measurement of bone density, trace elements, biomechanical properties and immunocytochemicals

International Nuclear Information System (INIS)

Aras, N.K.; Korkusuz, F.; Akkas, N.; Laleli, Y.; Kuscu, L.; Gunel, U.

1996-01-01

Osteoporosis is defined as an absolute decrease in the amount of bone to a level below required for mechanical support. It is an important bone disease in elderly people in many countries. Unfortunately, there is no reliable statistical data in Turkey for the incidence of osteoporosis. A decrease in bone mass is the important cause in fractures in osteoporosis. Therefore, we intend to study both bone density and other variables such as trace elements, biomechanical properties and other immunocytochemicals in bone, all combined might give an information about the cause and prevention of osteoporosis. (author)

Cerebrospinal Fluid Pressure: Revisiting Factors Influencing Optic Nerve Head Biomechanics

Science.gov (United States)

Hua, Yi; Voorhees, Andrew P.; Sigal, Ian A.

2018-01-01

Purpose To model the sensitivity of the optic nerve head (ONH) biomechanical environment to acute variations in IOP, cerebrospinal fluid pressure (CSFP), and central retinal artery blood pressure (BP). Methods We extended a previously published numerical model of the ONH to include 24 factors representing tissue anatomy and mechanical properties, all three pressures, and constraints on the optic nerve (CON). A total of 8340 models were studied to predict factor influences on 98 responses in a two-step process: a fractional factorial screening analysis to identify the 16 most influential factors, followed by a response surface methodology to predict factor effects in detail. Results The six most influential factors were, in order: IOP, CON, moduli of the sclera, lamina cribrosa (LC) and dura, and CSFP. IOP and CSFP affected different aspects of ONH biomechanics. The strongest influence of CSFP, more than twice that of IOP, was on the rotation of the peripapillary sclera. CSFP had similar influence on LC stretch and compression to moduli of sclera and LC. On some ONHs, CSFP caused large retrolamina deformations and subarachnoid expansion. CON had a strong influence on LC displacement. BP overall influence was 633 times smaller than that of IOP. Conclusions Models predict that IOP and CSFP are the top and sixth most influential factors on ONH biomechanics. Different IOP and CSFP effects suggest that translaminar pressure difference may not be a good parameter to predict biomechanics-related glaucomatous neuropathy. CON may drastically affect the responses relating to gross ONH geometry and should be determined experimentally. PMID:29332130

Biomechanics of coupled motion in the cervical spine during simulated whiplash in patients with pre-existing cervical or lumbar spinal fusion: A Finite Element Study.

Science.gov (United States)

Huang, H; Nightingale, R W; Dang, A B C

2018-01-01

Loss of motion following spine segment fusion results in increased strain in the adjacent motion segments. However, to date, studies on the biomechanics of the cervical spine have not assessed the role of coupled motions in the lumbar spine. Accordingly, we investigated the biomechanics of the cervical spine following cervical fusion and lumbar fusion during simulated whiplash using a whole-human finite element (FE) model to simulate coupled motions of the spine. A previously validated FE model of the human body in the driver-occupant position was used to investigate cervical hyperextension injury. The cervical spine was subjected to simulated whiplash exposure in accordance with Euro NCAP (the European New Car Assessment Programme) testing using the whole human FE model. The coupled motions between the cervical spine and lumbar spine were assessed by evaluating the biomechanical effects of simulated cervical fusion and lumbar fusion. Peak anterior longitudinal ligament (ALL) strain ranged from 0.106 to 0.382 in a normal spine, and from 0.116 to 0.399 in a fused cervical spine. Strain increased from cranial to caudal levels. The mean strain increase in the motion segment immediately adjacent to the site of fusion from C2-C3 through C5-C6 was 26.1% and 50.8% following single- and two-level cervical fusion, respectively (p = 0.03, unpaired two-way t -test). Peak cervical strains following various lumbar-fusion procedures were 1.0% less than those seen in a healthy spine (p = 0.61, two-way ANOVA). Cervical arthrodesis increases peak ALL strain in the adjacent motion segments. C3-4 experiences greater changes in strain than C6-7. Lumbar fusion did not have a significant effect on cervical spine strain. Cite this article : H. Huang, R. W. Nightingale, A. B. C. Dang. Biomechanics of coupled motion in the cervical spine during simulated whiplash in patients with pre-existing cervical or lumbar spinal fusion: A Finite Element Study. Bone Joint Res 2018;7:28-35. DOI: 10

Keratoconus Progression Induced by In Vitro Fertilization Treatment.

Science.gov (United States)

Yuksel, Erdem; Yalinbas, Duygu; Aydin, Bahri; Bilgihan, Kamil

2016-01-01

To evaluate patients with keratoconus who manifested progression after in vitro fertilization (IVF) treatment. Patients with keratoconus who received IVF treatment were included in this study. None of the patients became pregnant as a result of the IVF treatment. Progression of keratoconus was determined by changes in corrected distance visual acuity and/or topographic changes and subjective assessments. Three patients with keratoconus received IVF treatment and keratoconus progression was detected in all 6 eyes of the patients. The mean age of the patients was 32.3 ± 3.6 years (range: 28 to 36 years) and the mean follow-up duration was 15.6 ± 3.2 months (range: 12 to 18 months). The mean and the maximum keratometry values increased and corrected distance visual acuity decreased after 2.3 IVF treatments. Drugs used in IVF treatment increase estrogen levels, which may affect corneal biomechanics and induce progression of keratoconus. Corneal cross-linking treatment could be offered to minimize the risk of keratoconus progression before IVF treatment. Copyright 2016, SLACK Incorporated.

Hip joint biomechanics in those with and without post-traumatic knee osteoarthritis after anterior cruciate ligament injury.

Science.gov (United States)

Wellsandt, E; Zeni, J A; Axe, M J; Snyder-Mackler, L

2017-12-01

Anterior cruciate ligament injury results in altered kinematics and kinetics in the knee and hip joints that persist despite surgical reconstruction and rehabilitation. Abnormal movement patterns and a history of osteoarthritis are risk factors for articular cartilage degeneration in additional joints. The purpose of this study was to determine if hip joint biomechanics early after anterior cruciate ligament injury and reconstruction differ between patients with and without post-traumatic knee osteoarthritis 5years after reconstruction. The study's rationale was that individuals who develop knee osteoarthritis after anterior cruciate ligament injury may also demonstrate large alterations in hip joint biomechanics. Nineteen athletes with anterior cruciate ligament injury completed standard gait analysis before (baseline) and after (post-training) extended pre-operative rehabilitation and at 6months, 1year, and 2years after reconstruction. Weightbearing knee radiographs were completed 5years after reconstruction to identify medial compartment osteoarthritis. Five of 19 patients had knee osteoarthritis at 5years after anterior cruciate ligament reconstruction. Patients with knee osteoarthritis at 5years walked with smaller sagittal plane hip angles (P: 0.043) and lower sagittal (P: 0.021) and frontal plane (P: 0.042) external hip moments in the injured limb before and after reconstruction compared to those without knee osteoarthritis. The current findings suggest hip joint biomechanics may be altered in patients who develop post-traumatic knee osteoarthritis. Further study is needed to confirm whether the risk of non-traumatic hip pathology is increased after anterior cruciate ligament injury and if hip joint biomechanics influence its development. Copyright © 2017 Elsevier Ltd. All rights reserved.

Biomechanics of the elbow joint in tennis players.

NARCIS (Netherlands)

Eygendaal, D.; Rahussen, F.T.; Diercks, R.L.

2007-01-01

Elbow injuries constitute a sizeable percentage of tennis injuries. A basic understanding of biomechanics of tennis and analysis of forces, loads and motions of the elbow during tennis can will improve the understanding of the pathophysiology of these injuries. All different strokes in tennis have a

Masticatory System Biomechanical Photoelastic Simulation fot the Comparision of the Conventional and Uni-Lock Systems in Mandibular Osteosynthesis

Directory of Open Access Journals (Sweden)

Jose Luis Cebrian Carretero

2017-08-01

Full Text Available The biomechanical consequences of the interaction between titanium trauma plates and screws and the fractured mandible are still a matter of investigation. The mathematical and biomechanical models that have been developed show limitations and the experimental studies are not able to reproduce muscle forces and internal stress distributions in the bone-implant interface and mandibular structure. In the present article we show a static simulator of the masticatory system to demonstrate in epoxy resin mandibular models, by means of 3D (three-dimensional photoelasticity, the stress distribution using different osteosynthesis methods in the mandibular angle fractures. The results showed that the simulator and 3D photoelasticity were a useful method to study interactions between bone and osteosynthesis materials. The “Lock” systems can be considered the most favourable method due to their stress distribution in the epoxy resin mandible. 3D photoelasticity in epoxy resin models is a useful method to evaluate stress distribution for biomechanical studies. Regarding to mandibular osteosynthesis, “lock” plates offer the most favourable stress distribution due to being less aggressive to the bone

In vitro precultivation alleviates post-implantation inflammation and enhances development of tissue-engineered tubular cartilage

Energy Technology Data Exchange (ETDEWEB)

Luo Xusong; Zhou Guangdong; Liu Wei; Zhang Wenjie; Cui Lei; Cao Yilin [Department of Plastic and Reconstructive Surgery, Shanghai Key Laboratory of Tissue Engineering, Shanghai 9th People' s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011 (China); Cen Lian, E-mail: guangdongzhou@126.co, E-mail: yilincao@yahoo.co [National Tissue Engineering Center of China, Shanghai 200011 (China)

2009-04-15

Tissue-engineered tubular cartilage is a promising graft for tracheal reconstruction. But polylactic acid/polyglycolic acid (PLA/PGA) fibers, the frequently used scaffolds for cartilage engineering, often elicit an obvious inflammation response following implantation into immunocompetent animals. We propose that the inflammation could be alleviated by in vitro precultivation. In this study, after in vitro culture for either 2 days (direct implantation group (DI)) or for 2 weeks (precultivation implantation group (PI)), autologous tubular chondrocyte-PLA/PGA constructs were subcutaneously implanted into rabbits. In the PI group, after 2 weeks of precultivation, most of the fibers were found to be completely embedded in an extracellular matrix (ECM) produced by the chondrocytes. Importantly, no obvious inflammatory reaction was observed after in vivo implantation and homogeneous cartilage-like tissue was formed with biomechanical properties close to native tracheal cartilage at 4 weeks post-implantation. In the DI group, however, an obvious inflammatory reaction was observed within and around the cell-scaffold constructs at 1 week implantation and only sporadic cartilage islands separated by fibrous tissue were observed at 4 weeks. These results demonstrated that the post-implantation inflammatory reaction could be alleviated by in vitro precultivation, which contributes to the formation of satisfactory tubular cartilage for tracheal reconstruction.

Biomechanics/risk management (Working Group 2)

DEFF Research Database (Denmark)

Sanz, Mariano; Naert, Ignace; Gotfredsen, Klaus

2009-01-01

INTRODUCTION: The remit of this workgroup was to update the existing knowledge base in biomechanical factors, navigation systems and medications that may affect the outcome of implant therapy. MATERIAL AND METHODS: The literature was systematically searched and critically reviewed. Five manuscripts...... were produced in five specific topics identified as areas where innovative approaches have been developed in biomechanical factors, navigation systems and medications that may affect the outcome of implant therapy. RESULTS: The results and conclusions of the review process are presented...... survival and complications of implant supported restorations? * A systematic review on the accuracy and the clinical outcome of computer-guided template based implant dentistry. * What is the impact of systemic bisphosphonates on patients undergoing oral implant therapy? * What is the impact...

Tree Branching: Leonardo da Vinci's Rule versus Biomechanical Models

Science.gov (United States)

Minamino, Ryoko; Tateno, Masaki

2014-01-01

This study examined Leonardo da Vinci's rule (i.e., the sum of the cross-sectional area of all tree branches above a branching point at any height is equal to the cross-sectional area of the trunk or the branch immediately below the branching point) using simulations based on two biomechanical models: the uniform stress and elastic similarity models. Model calculations of the daughter/mother ratio (i.e., the ratio of the total cross-sectional area of the daughter branches to the cross-sectional area of the mother branch at the branching point) showed that both biomechanical models agreed with da Vinci's rule when the branching angles of daughter branches and the weights of lateral daughter branches were small; however, the models deviated from da Vinci's rule as the weights and/or the branching angles of lateral daughter branches increased. The calculated values of the two models were largely similar but differed in some ways. Field measurements of Fagus crenata and Abies homolepis also fit this trend, wherein models deviated from da Vinci's rule with increasing relative weights of lateral daughter branches. However, this deviation was small for a branching pattern in nature, where empirical measurements were taken under realistic measurement conditions; thus, da Vinci's rule did not critically contradict the biomechanical models in the case of real branching patterns, though the model calculations described the contradiction between da Vinci's rule and the biomechanical models. The field data for Fagus crenata fit the uniform stress model best, indicating that stress uniformity is the key constraint of branch morphology in Fagus crenata rather than elastic similarity or da Vinci's rule. On the other hand, mechanical constraints are not necessarily significant in the morphology of Abies homolepis branches, depending on the number of daughter branches. Rather, these branches were often in agreement with da Vinci's rule. PMID:24714065

Tree branching: Leonardo da Vinci's rule versus biomechanical models.

Science.gov (United States)

Minamino, Ryoko; Tateno, Masaki

2014-01-01

This study examined Leonardo da Vinci's rule (i.e., the sum of the cross-sectional area of all tree branches above a branching point at any height is equal to the cross-sectional area of the trunk or the branch immediately below the branching point) using simulations based on two biomechanical models: the uniform stress and elastic similarity models. Model calculations of the daughter/mother ratio (i.e., the ratio of the total cross-sectional area of the daughter branches to the cross-sectional area of the mother branch at the branching point) showed that both biomechanical models agreed with da Vinci's rule when the branching angles of daughter branches and the weights of lateral daughter branches were small; however, the models deviated from da Vinci's rule as the weights and/or the branching angles of lateral daughter branches increased. The calculated values of the two models were largely similar but differed in some ways. Field measurements of Fagus crenata and Abies homolepis also fit this trend, wherein models deviated from da Vinci's rule with increasing relative weights of lateral daughter branches. However, this deviation was small for a branching pattern in nature, where empirical measurements were taken under realistic measurement conditions; thus, da Vinci's rule did not critically contradict the biomechanical models in the case of real branching patterns, though the model calculations described the contradiction between da Vinci's rule and the biomechanical models. The field data for Fagus crenata fit the uniform stress model best, indicating that stress uniformity is the key constraint of branch morphology in Fagus crenata rather than elastic similarity or da Vinci's rule. On the other hand, mechanical constraints are not necessarily significant in the morphology of Abies homolepis branches, depending on the number of daughter branches. Rather, these branches were often in agreement with da Vinci's rule.

The Biomechanics of Cranial Forces During Figure Skating Spinning Elements.

Science.gov (United States)

Wang, David H; Kostyun, Regina O; Solomito, Matthew J

2015-03-01

Several facets of figure skating, such as the forces associated with jumping and landing, have been evaluated, but a comprehensive biomechanical understanding of the cranial forces associated with spinning has yet to be explored. The purpose of this case study was to quantify the cranial rotational acceleration forces generated during spinning elements. This case report was an observational, biomechanical analysis of a healthy, senior-level, female figure skating athlete who is part of an on-going study. A triaxial accelerometer recorded the gravitational forces (G) during seven different spinning elements. Our results found that the layback spin generated significant cranial force and these forces were greater than any of the other spin elements recorded. These forces led to physical findings of ruptured capillaries, dizziness, and headaches in our participant.

Role of biomechanics in the understanding of normal, injured, and healing ligaments and tendons

Directory of Open Access Journals (Sweden)

Jung Ho-Joong

2009-05-01

Full Text Available Abstract Ligaments and tendons are soft connective tissues which serve essential roles for biomechanical function of the musculoskeletal system by stabilizing and guiding the motion of diarthrodial joints. Nevertheless, these tissues are frequently injured due to repetition and overuse as well as quick cutting motions that involve acceleration and deceleration. These injuries often upset this balance between mobility and stability of the joint which causes damage to other soft tissues manifested as pain and other morbidity, such as osteoarthritis. The healing of ligament and tendon injuries varies from tissue to tissue. Tendinopathies are ubiquitous and can take up to 12 months for the pain to subside before one could return to normal activity. A ruptured medial collateral ligament (MCL can generally heal spontaneously; however, its remodeling process takes years and its biomechanical properties remain inferior when compared to the normal MCL. It is also known that a midsubstance anterior cruciate ligament (ACL tear has limited healing capability, and reconstruction by soft tissue grafts has been regularly performed to regain knee function. However, long term follow-up studies have revealed that 20–25% of patients experience unsatisfactory results. Thus, a better understanding of the function of ligaments and tendons, together with knowledge on their healing potential, may help investigators to develop novel strategies to accelerate and improve the healing process of ligaments and tendons. With thousands of new papers published in the last ten years that involve biomechanics of ligaments and tendons, there is an increasing appreciation of this subject area. Such attention has positively impacted clinical practice. On the other hand, biomechanical data are complex in nature, and there is a danger of misinterpreting them. Thus, in these review, we will provide the readers with a brief overview of ligaments and tendons and refer them to

Role of biomechanics in the understanding of normal, injured, and healing ligaments and tendons

Science.gov (United States)

Jung, Ho-Joong; Fisher, Matthew B; Woo, Savio L-Y

2009-01-01

Ligaments and tendons are soft connective tissues which serve essential roles for biomechanical function of the musculoskeletal system by stabilizing and guiding the motion of diarthrodial joints. Nevertheless, these tissues are frequently injured due to repetition and overuse as well as quick cutting motions that involve acceleration and deceleration. These injuries often upset this balance between mobility and stability of the joint which causes damage to other soft tissues manifested as pain and other morbidity, such as osteoarthritis. The healing of ligament and tendon injuries varies from tissue to tissue. Tendinopathies are ubiquitous and can take up to 12 months for the pain to subside before one could return to normal activity. A ruptured medial collateral ligament (MCL) can generally heal spontaneously; however, its remodeling process takes years and its biomechanical properties remain inferior when compared to the normal MCL. It is also known that a midsubstance anterior cruciate ligament (ACL) tear has limited healing capability, and reconstruction by soft tissue grafts has been regularly performed to regain knee function. However, long term follow-up studies have revealed that 20–25% of patients experience unsatisfactory results. Thus, a better understanding of the function of ligaments and tendons, together with knowledge on their healing potential, may help investigators to develop novel strategies to accelerate and improve the healing process of ligaments and tendons. With thousands of new papers published in the last ten years that involve biomechanics of ligaments and tendons, there is an increasing appreciation of this subject area. Such attention has positively impacted clinical practice. On the other hand, biomechanical data are complex in nature, and there is a danger of misinterpreting them. Thus, in these review, we will provide the readers with a brief overview of ligaments and tendons and refer them to appropriate methodologies used to

Biochemical and biomechanical characterisation of equine cervical facet joint cartilage.

Science.gov (United States)

O'Leary, S A; White, J L; Hu, J C; Athanasiou, K A

2018-04-15

The equine cervical facet joint is a site of significant pathology. Located bilaterally on the dorsal spine, these diarthrodial joints work in conjunction with the intervertebral disc to facilitate appropriate spinal motion. Despite the high prevalence of pathology in this joint, the facet joint is understudied and thus lacking in viable treatment options. The goal of this study was to characterise equine facet joint cartilage and provide a comprehensive database describing the morphological, histological, biochemical and biomechanical properties of this tissue. Descriptive cadaver studies. A total of 132 facet joint surfaces were harvested from the cervical spines of six skeletally mature horses (11 surfaces per animal) for compiling biomechanical and biochemical properties of hyaline cartilage of the equine cervical facet joints. Gross morphometric measurements and histological staining were performed on facet joint cartilage. Creep indentation and uniaxial strain-to-failure testing were used to determine the biomechanical compressive and tensile properties. Biochemical assays included quantification of total collagen, sulfated glycosaminoglycan and DNA content. The facet joint surfaces were ovoid in shape with a flat articular surface. Histological analyses highlighted structures akin to articular cartilage of other synovial joints. In general, biomechanical and biochemical properties did not differ significantly between the inferior and superior joint surfaces as well as among spinal levels. Interestingly, compressive and tensile properties of cervical facet articular cartilage were lower than those of articular cartilage from other previously characterised equine joints. Removal of the superficial zone reduced the tissue's tensile strength, suggesting that this zone is important for the tensile integrity of the tissue. Facet surfaces were sampled at a single, central location and do not capture the potential topographic variation in cartilage properties. This

Artificial playing surfaces research: a review of medical, engineering and biomechanical aspects.

Science.gov (United States)

Dixon, S J; Batt, M E; Collop, A C

1999-05-01

In this paper, current knowledge of artificial playing surfaces is reviewed. Research status in the fields of sports medicine, engineering and biomechanics is described. A multidisciplinary approach to the study of artificial sports surface properties is recommended. The development of modelling techniques to characterise fundamental material properties is described as the most appropriate method for the unique specification of material properties such as stiffness and damping characteristics. It is suggested that the systematic manipulation of fundamental surface material properties in biomechanics research will allow the identification of subject responses to clearly defined surface variation. It is suggested that subjects should be grouped according to characteristic behaviour on specific sports surfaces. It is speculated that future biomechanics research will identify subject criterion related to differing group responses. The literature evidence of interactions between sports shoes and sports surfaces leads to the suggestion that sports shoe and sports surface companies should work together in the development of ideal shoe - surface combinations for particular groups of subjects.

Bone plate composed of a ternary nano-hydroxyapatite/polyamide 66/glass fiber composite: biomechanical properties and biocompatibility.

Science.gov (United States)

Qiao, Bo; Li, Jidong; Zhu, Qingmao; Guo, Shuquan; Qi, Xiaotong; Li, Weichao; Wu, Jun; Liu, Yang; Jiang, Dianming

2014-01-01

An ideal bone plate for internal fixation of bone fractures should have good biomechanical properties and biocompatibility. In this study, we prepared a new nondegradable bone plate composed of a ternary nano-hydroxyapatite/polyamide 66/glass fiber (n-HA/PA66/GF) composite. A breakage area on the n-HA/PA66/GF plate surface was characterized by scanning electron microscopy. Its mechanical properties were investigated using bone-plate constructs and biocompatibility was evaluated in vitro using bone marrow-derived mesenchymal stem cells. The results confirmed that adhesion between the n-HA/PA66 matrix and the glass fibers was strong, with only a few fibers pulled out at the site of breakage. Fractures fixed by the n-HA/PA66/GF plate showed lower stiffness and had satisfactory strength compared with rigid fixation using a titanium plate. Moreover, the results with regard to mesenchymal stem cell morphology, MTT assay, Alizarin Red S staining, enzyme-linked immunosorbent assay, and reverse transcription polymerase chain reaction for alkaline phosphatase and osteocalcin showed that the n-HA/PA66/GF composite was suitable for attachment and proliferation of mesenchymal stem cells, and did not have a negative influence on matrix mineralization or osteogenic differentiation of mesenchymal stem cells. These observations indicate that the n-HA/PA66/GF plate has good biomechanical properties and biocompatibility, and may be considered a new option for internal fixation in orthopedic surgery.

Functional assessment of the ex vivo vocal folds through biomechanical testing: A review

Science.gov (United States)

Dion, Gregory R.; Jeswani, Seema; Roof, Scott; Fritz, Mark; Coelho, Paulo; Sobieraj, Michael; Amin, Milan R.; Branski, Ryan C.

2016-01-01

The human vocal folds are complex structures made up of distinct layers that vary in cellular and extracellular composition. The mechanical properties of vocal fold tissue are fundamental to the study of both the acoustics and biomechanics of voice production. To date, quantitative methods have been applied to characterize the vocal fold tissue in both normal and pathologic conditions. This review describes, summarizes, and discusses the most commonly employed methods for vocal fold biomechanical testing. Force-elongation, torsional parallel plate rheometry, simple-shear parallel plate rheometry, linear skin rheometry, and indentation are the most frequently employed biomechanical tests for vocal fold tissues and each provide material properties data that can be used to compare native tissue verses diseased for treated tissue. Force-elongation testing is clinically useful, as it allows for functional unit testing, while rheometry provides physiologically relevant shear data, and nanoindentation permits micrometer scale testing across different areas of the vocal fold as well as whole organ testing. Thoughtful selection of the testing technique during experimental design to evaluate a hypothesis is important to optimizing biomechanical testing of vocal fold tissues. PMID:27127075

Bioactivity of sol-gel-derived TiO2 coating on polyetheretherketone: In vitro and in vivo studies.

Science.gov (United States)

Shimizu, Takayoshi; Fujibayashi, Shunsuke; Yamaguchi, Seiji; Yamamoto, Koji; Otsuki, Bungo; Takemoto, Mitsuru; Tsukanaka, Masako; Kizuki, Takashi; Matsushita, Tomiharu; Kokubo, Tadashi; Matsuda, Shuichi

2016-04-15

A polyetheretherketone (PEEK) surface was modified using a sol-gel-derived TiO2 coating in order to confer bone-bonding ability. To enhance the bonding strength of the coating layer, pretreatment with either O2 plasma or sandblasting was performed prior to sol-gel coating. Additionally, post-treatment with acid was carried out to confer apatite (calcium phosphate)-forming ability to the surface. Biomechanical and histological analyses performed using an in vivo rabbit tibia model showed that PEEK surfaces modified with sol-gel-derived TiO2 and acid post-treatment had better bone-bonding properties than uncoated PEEK surfaces. These modified surfaces also performed well in terms of their in vitro cell responses due to their modified surface chemistries and topographies. Although O2 plasma or sandblasting treatment were, for the most part, equivocal in terms of performance, we conclude that sol-gel-derived TiO2 coating followed by acid post-treatment significantly improves the bone bonding ability of PEEK surfaces, thus rendering them optimal for their use in surgical implants. The role of polyetheretherketone (PEEK) as an alternative biomaterial to conventional metallic implant materials has become increasingly important. However, its low bone bonding ability is yet to be resolved. This in vivo and in vitro investigation on the functionalization of PEEK surfaces highlights the utility of this material in clinical interventions that require implants, and may extend range of applications of PEEK. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Corneal biomechanical properties in healthy children measured by corneal visualization scheimpflug technology.

Science.gov (United States)

He, Miao; Ding, Hui; He, Hong; Zhang, Chi; Liu, Liangping; Zhong, Xingwu

2017-05-17

The aim of this study was to evaluate corneal biomechanical properties in a population of healthy children in China using corneal visualization Scheimpflug technology (CST). All children underwent complete bi-ocular examinations. CST provided intraocular pressure (IOP) and corneal biomechanical parameters, including time, velocity, length and deformation amplitude at first applanation (A1T, A1V, A1L, A1DA), at second applanation (A2T, A2V, A2L, A2DA), highest concavity time (HCT), maximum deformation amplitude (MDA), peak distance (PD), and radius of curvature (RoC). Pearson correlation analysis was used to assess the impacts of demographic factors, central corneal thickness (CCT), spherical equivalent (SE), and IOP on corneal biomechanics. One hundred eight subjects (32 girls and 76 boys) with the mean age of 10.80 ± 4.13 years (range 4 to18 years) were included in the final analyses. The right and left eyes were highly symmetrical in SE (p = 0.082), IOP (p = 0.235), or CCT (p = 0.210). Mean A1T of the right eyes was 7.424 ± 0.340 ms; the left eyes 7.451 ± 0.365 ms. MDA was 0.993 ± 0.102 mm in the right eyes and 0.982 ± 0.100 mm in the left eyes. Mean HCT of the right eyes was 16.675 ± 0.502 ms; the left eyes 16.735 ± 0.555 ms. All CST parameters of both eye were remarkably symmetrical with the exception of A2L (p = 0.006), A1DA (p = 0.025). The majority of CST parameters of both eyes were significantly correlated with CCT and IOP (p children eyes. Several CST biomechanical parameters in children are modified by CCT and IOP.