{"title":"A Structural Constitutive Model for Planar Collagenous Tissues That Integrates SALS-Derived Fiber Orientation Data","authors":"M. Sacks","doi":"10.1115/imece2001/bed-23065","DOIUrl":"https://doi.org/10.1115/imece2001/bed-23065","url":null,"abstract":"\u0000 Structurally based constitutive models attempt to exploit the tissue composition and structure to avoid ambiguities in material characterization, and offer insight into the function, structure, and mechanics of tissue components. In the structural approach, the tissues total strain energy is assumed to be the sum of the individual fiber strain energies [1–3]. Although theoretically complete, the fiber architecture must be estimated from assumed distributions and “backed-out” from the mechanical data. Thus, fall realization of the structural approach is significantly limited without direct quantitative structural information to either validate structural model predictions or for direct implementation into the model. This limitation of the structural constitutive modeling approach motivated the development of the following structural constitutive model for planar collagenous tissue that directly incorporates the experimentally measured angular distribution of collagen fibers.","PeriodicalId":7238,"journal":{"name":"Advances in Bioengineering","volume":"14 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84552233","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Flow Evaluation of a Compliant Coronary Artery Anastomosis Model","authors":"Pedro D. Pedroso, R. Venugopalan, A. Anayiotos","doi":"10.1115/imece2001/bed-23123","DOIUrl":"https://doi.org/10.1115/imece2001/bed-23123","url":null,"abstract":"\u0000 Coronary artery bypass grafting (CABG) is a common surgical procedure for coronary artery diseases or severe stenosis of the coronary arteries. It makes use of a peripheral vein (usually the saphenous vein of the leg) to form a conduit between the aorta and the coronary artery distal to the obstructive lesion. It is rapidly becoming the treatment of choice in cases where the vessel is more than 70% occluded or when angioplasty is not possible. However, a significant number of grafts subsequently fail due to acute thrombosis in the early post-operative period or to restenosis within months or years. Intimal thickening in the CABG anastomosis has been implicated as the major cause of restenosis and long-term graft failure. Several studies point to the interplay between non-uniform hemodynamics (including disturbed flows and recirculation zones), wall shear stress, and long particle residence time as possible etiologies. An important feature of the anastomosis geometry, is a bulge that forms at the veno-arterial junction. This sinus forms as a result of the stretching of the thin venous wall when the graft is exposed to aortic pressure conditions. The resultant sinus, and the impedance mismatch of the vein-artery connection, contribute to a complicated region of highly disturbed flow at the divider and may have a primary role in restenosis and final failure of the graft.","PeriodicalId":7238,"journal":{"name":"Advances in Bioengineering","volume":"27 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85169728","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A Material Model for Shortening-Dependent Stiffness of Tracheal Smooth Muscle","authors":"P. A. Sarma, R. Pidaparti, R. Meiss","doi":"10.1115/imece2001/bed-23161","DOIUrl":"https://doi.org/10.1115/imece2001/bed-23161","url":null,"abstract":"\u0000 The objectives of the present study are to develop a material model of a tracheal smooth muscle tissue from experimental data, and to simulate the mechanical response through a three-dimensional nonlinear finite element analysis. The developed material model and simulation models are validated against the experimental data. The results obtained indicate that the approach and the material model developed are useful for describing the length-dependent characteristics of tracheal smooth muscle tissue.","PeriodicalId":7238,"journal":{"name":"Advances in Bioengineering","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91232695","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Relationships Between Transfemoral Socket Interface Pressure and Hip Moment of Residual Limb With a 4-Bar Pneumatic Knee During Stance Phase of Gait","authors":"Junghwa Hong, J. Ryu, Shin-Ki Kim, M. Mun","doi":"10.1115/imece2001/bed-23051","DOIUrl":"https://doi.org/10.1115/imece2001/bed-23051","url":null,"abstract":"\u0000 For transfemoral amputees, the biomechanical interaction between the stump and the prosthetic socket during stance phase of gait is critically important to achieve normal-like ambulation. It is widely accepted that abnormal socket interface pressure distribution and temporal behavior cause pathology in the stump directly affecting gait of amputees. Therefore, many investigators have studied static and dynamic socket pressure behaviors. The results of the investigations suggested that the pressure changes during gait of transfemoral amputees are closely related to the prosthetic alignment, the socket shape, the stump size, and the residual muscle activity [1,2]. In addition, the temporal changes of hip moment during ambulation may affect the socket pressure distributions of transfemoral amputees [3,4]. However, relationships between the hip moment and the socket pressure have not been well understood. The purpose of this study is to investigate the relationships between the hip moment and the socket pressure during amputee gait with transfemoral prostheses.","PeriodicalId":7238,"journal":{"name":"Advances in Bioengineering","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90351218","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Shape Opimization of Femoral Components of an Artificial Hip Prosthesis Using the Three-Dimensional P-Version Finite Element Method","authors":"M. Higa, I. Nishimura, H. Tanino, Y. Mitamura","doi":"10.1115/imece2001/bed-23012","DOIUrl":"https://doi.org/10.1115/imece2001/bed-23012","url":null,"abstract":"\u0000 The three-dimensional shape optimization of cemented total hip arthroplasty (THA) was introduced in this paper. The P-version Finite Element Method (FEM) combined with an optimization procedure was used to minimize the peak stress in the bone cement near the tip of the implant. Six-design variables were used in this study. Each variable represents the dimension of the medial-lateral width and anterior-posterior width of the three levels (proximal, distal and middle) of cross sectional area of the prosthesis. The results of the design optimization showed considerable reduction in stress concentration compared to the initial design that is currently used clinically.","PeriodicalId":7238,"journal":{"name":"Advances in Bioengineering","volume":"7 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90452422","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Numerical Simulation and Evaluation of the Reduced-Platen Compression Test for Estimating Cancellous Bone Mechanical Properties in the Rat","authors":"H. Hogan, Kent D. Harms, H. Sampson","doi":"10.1115/imece2001/bed-23030","DOIUrl":"https://doi.org/10.1115/imece2001/bed-23030","url":null,"abstract":"\u0000 Animal models are utilized in numerous research studies aimed at better understanding skeletal biology, bone biomechanics, and many orthopedic diseases or pathologies. Prominent among these animal models are rodents, most commonly rats and mice. In estimating bone mechanical properties in these animals, cortical bone is routinely assessed by bending one of the long bones such as the femur or tibia, which targets the mid-diaphysis region. Testing specimens of isolated cancellous bone is exceedingly challenging, however, even for the larger rat skeleton. Recognizing the prominence and importance of cancellous bone mechanical properties has led to increased mechanical testing of vertebra and femoral neck specimens in skeletal research employing rats and mice. The specimens in these tests actually consist of a combination of both cortical and cancellous tissue, however. In an attempt to more closely approximate the ideal of isolated cancellous bone specimens a method has been developed recently for testing specimens from the proximal tibia metaphysis and distal femoral metaphysis [1]. In either case, the specimen in this so-called “reduced-platen compression” (RPC) test consists of a section of the metaphysis containing both cortical and cancellous bone. The specimen and test configuration are illustrated schematically in Fig. 1.","PeriodicalId":7238,"journal":{"name":"Advances in Bioengineering","volume":"14 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81059685","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Characterization of Agarose and Alginate Gels for Cell Compression Experiments","authors":"J. Srinivasan, N. Mukherjee","doi":"10.1115/imece2001/bed-23143","DOIUrl":"https://doi.org/10.1115/imece2001/bed-23143","url":null,"abstract":"\u0000 Various concentrations of folly hydrated agarose and alginate gel formed into cuboid shapes are tested in unconfined compression with impermeable plattens to determine Young’s modulus at equilibrium (relaxed elastic modulus) of the gel blocks. Repeat testing of a single block was performed to assess intra-test variability in testing conditions and deterioration of the gels during the testing procedure. Variability in material properties of gels formed in a single batch was assessed. The data was compared with values obtained from a search of relevant literature. While general trends in the data were the same (increased modulus for larger concentration gel), large differences in actual values of material properties were noted which could be ascribed to differences in the method and conditions of testing and theoretical models used to obtain material properties. Accurate properties of the gels are needed in gel-cell (cells embedded in gel) compression experiments in order to extract accurate cellular properties. It is concluded that it is necessary to use the gel material properties obtained under the same conditions of testing in order to determine cellular material properties in gel-cell compression experiments.","PeriodicalId":7238,"journal":{"name":"Advances in Bioengineering","volume":"99 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81280454","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Improved Histologic Analysis of Component Distribution and Wall Behavior in Cyanoacrylate-Embolized Vessels","authors":"W. Calvo, B. Lieber, A. Wakhloo, L. Hopkins","doi":"10.1115/imece2001/bed-23131","DOIUrl":"https://doi.org/10.1115/imece2001/bed-23131","url":null,"abstract":"\u0000 Use of embolic agents is currently an accepted treatment modality among neurointerventional clinicians in order to completely occlude abnormal shunts in the cerebral vasculature known as arteriovenous malformations or AVMs. The first cyanoacrylate polymer recently approved by the US Food and Drug Administration for use in humans is n-butyl 2-cyanoacrylate (NBCA). In order to control the polymerization time of NBCA, as well as to opacify the mixture for angiographic visualization, an iodized poppyseed oil-based contrast agent (Lipiodol) is added to the NBCA. Glacial acetic acid is also used to delay polymerization further by decreasing the pH of the mixture.","PeriodicalId":7238,"journal":{"name":"Advances in Bioengineering","volume":"49 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78774533","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The Role of Biomechanics in the Modern Biomedical Engineering Undergraduate Curriculum","authors":"R. Spilker, R. Kamm","doi":"10.1115/imece2001/bed-23023","DOIUrl":"https://doi.org/10.1115/imece2001/bed-23023","url":null,"abstract":"\u0000 During the Summer and Fall of 2000, the Whitaker Foundation engaged the biomedical engineering community in a curriculum assessment and vision exercise that included: collection and posting (www.Whitaker.org) of a curriculum database from departments and programs in bioengineering (note that within this document, bioengineering is understood to be synonymous with biomedical engineering); identification of key curricular topic areas and facilitators for each of these areas; posting of white papers by the facilitators; and a period of community comment. This activity culminated in the Whitaker Educational Summit, held in December 2000, at which representatives of virtually all US bioengineering departments and programs, numerous international participants, and those interested in establishing programs, gathered for a series of lectures and discussions on general topics in the undergraduate bioengineering curriculum, and for focused group discussions in each of the topic areas. Summary comments were prepared at that meeting by professional science writers and published at the Whitaker web site, and a period of comment followed. As facilitators for the area of biomechanics, and representatives of the US National Committee on Biomechanics, we offer a vision of biomechanics in the undergraduate bioengineering curriculum, and a set of recommendations that result from the. Whitaker process.","PeriodicalId":7238,"journal":{"name":"Advances in Bioengineering","volume":"347 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82980532","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A Device for Driving a Wire or a Drill Precisely in a Given Direction Through a Point Under Closed Sky Conditions","authors":"G. Danieli, G. Fragomeni, E. Giuzio","doi":"10.1115/imece2001/bed-23079","DOIUrl":"https://doi.org/10.1115/imece2001/bed-23079","url":null,"abstract":"\u0000 The paper presents a new device which allows the precise positioning of a guide through a point and in a given direction, or which can permit to reach a given bone section. Other devices exist mainly addressed to the insertion of a screw in the correct position on endo-medullary nails, but these are usually based on the knowledge of the geometry of the nail, and are therefore made by the maker of the nail. In other instances, often the doctors use trial drilling under fluoroscopy to place a kirshner wire in the required position. The actual device is instead based only on an aiming methodology resting on geometrical considerations. Previous knowledge of the position of such a point and direction, which can be given by a hole belonging to a plate or to an endo-medullary nail or can be part of the patient’s bone structure, is not necessary. This is due to the use of fluoroscopy coupled to the localisation of two aiming planes on whose interception is placed the line of interest. A first instrument developed on this principle found limited clinical success due to the complexity of the first kinematic chain used in the aiming process and to human error. A new version has been designed and is at present under construction, which solves the kinematic problem through a careful choice of a series of constraints enabling the aiming process to be divided in sub processes, thus gradually controlling the final result.","PeriodicalId":7238,"journal":{"name":"Advances in Bioengineering","volume":"3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89770909","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}