Advances in Bioengineering最新文献

{"title":"Mechanical Loading Modulates Gene Expression in Chondrocyte-Seeded Agarose Hydrogels","authors":"Sansan S. Lo, R. Mauck, Sara L. Seyhan, G. Palmer, V. Mow, C. Hung","doi":"10.1115/imece2001/bed-23145","DOIUrl":"https://doi.org/10.1115/imece2001/bed-23145","url":null,"abstract":"\u0000 A successful tissue engineered articular cartilage construct needs to possess mechanical, biochemical, and histological features similar to that of native cartilage in order to serve its load-bearing function. Agarose is a suitable scaffold material for chondrocyte cultures (1,2), allowing long-term maintenance of cell phenotype and the elaboration of a functional cartilage-like matrix. This culture system facilitates further elucidation of the roles of matrix and cell-matrix interactions in the regulation of chondrocyte response to mechanical loads. We have previously shown (3) that mechanical loading at a physiologic frequency can increase the rate of matrix deposition, increasing mechanical properties of the tissue engineered constructs (∼21 fold increases in HA over day 0 with loading vs. ∼4 fold increases for free swelling controls). We have also shown that dynamic loading of transiently transfected chondrocytes in agarose hydrogels for 1 hour at 10% strain increased aggrecan promoter activity by ∼1.5 fold (4). In this study we sought to further characterize the short term response of chondrocytes to static load (by measuring aggrecan promoter activity) and the effects of dynamic compression on aggrecan gene expression over a longer (3 day) culture period (by monitoring mRNA levels). Monitoring matrix gene expression during early times of culture, when there is little matrix accumulation and the cells deform directly with the matrix (5), may provide insights into cellular responses to strain and allow for the optimization of cartilage bioreactor conditions.","PeriodicalId":7238,"journal":{"name":"Advances in Bioengineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81162697","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":"3D Kinematic Analysis of the Carpometacarpal Joints","authors":"R. Patterson, M. El-shennawy, Koji Nakamura, S. Viegas","doi":"10.1115/imece2001/bed-23047","DOIUrl":"https://doi.org/10.1115/imece2001/bed-23047","url":null,"abstract":"\u0000 Carpometacarpal joint motion has been difficult to accurately measure with standard methods. There has been relatively little information on the kinematics of the 2nd through 5th carpometacapal (CMC) joints. It is however, generally accepted that the range of motion in the 2nd through the 5th CMC joints increases from the radial to the ulnar side of the hand, with the 2nd CMC joint being essentially immobile, while the 5th CMC joint simultaneously flexes and adducts1. The purpose of this study is to investigate the 3D dynamic kinematics of the 2nd – 5th CMC joints during flexion/extension motion (FEM), radio-ulnar deviation (RUD), and pronation/supination motion (PSM).","PeriodicalId":7238,"journal":{"name":"Advances in Bioengineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89562351","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":"Temporal Development of Material Properties in Free Swelling Chondrocyte-Seeded Agarose Constructs","authors":"Terri-Ann N. Kelly, C. C. Wang, N. Chahine, G. Ateshian, C. Hung","doi":"10.1115/imece2001/bed-23144","DOIUrl":"https://doi.org/10.1115/imece2001/bed-23144","url":null,"abstract":"\u0000 An understanding of chondrocyte mechanotransduction requires knowledge of the deformational fields within the tissue. Since the study of chondrocyte mechanotransduction in articular cartilage explants is hampered by its inhomogeneous biochemical composition and biomechanical properties, investigators have performed loading studies of chondrocyte-suspended hydrogel polymer systems such as agarose [1]. Prior to significant matrix elaboration by the cells, the agarose offers a uniform, uncharged three-dimensional (3D) mechanical environment for chondrocytes [2,3]. In this study, a technique, which combines video microscopy [4] and digital image correlation [5], was used to provide a novel characterization of the temporal changes in displacement field, apparent Young’s Modulus and apparent Poisson’s ratio of free swelling chondrocyte-seeded agarose constructs. Biochemical analysis was performed to permit correlation of these parameters with matrix elaboration.","PeriodicalId":7238,"journal":{"name":"Advances in Bioengineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89940394","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of Variations in Intraluminal Thrombus Constitutive Properties on Abdominal Aortic Aneurysm Wall Stress: A Parametric Study","authors":"Elena S. Di Martino, D. Whang, A. Redaelli, M. Makaroun, D. Vorp","doi":"10.1115/imece2001/bed-23120","DOIUrl":"https://doi.org/10.1115/imece2001/bed-23120","url":null,"abstract":"\u0000 The prevalence of abdominal aortic aneurysm (AAA) is growing together with population age, being 8.8% in a population above 65 years according to a recent study [1]. Deciding between elective surgical repair of AAA and watchful management is a complex issue due to the lack of reliable rupture risk indices. The maximum transverse diameter of AAA is most commonly used in clinical practice to base this decision. From a biomechanical viewpoint, AAA rupture is related to the balance between the stresses acting on the wall and strength of the wall tissue. Many different factors contribute to the stress within the aortic aneurysm wall, including the presence of intraluminal thrombus (ILT) [2–5], the local surface curvature [6] and material characteristics of the AAA wall [7], and the presence of local “stress concentrators” due to calcifications or local thinning. As regards the ILT, its role with respect to aneurysm wall stresses has given rise to many hypotheses. Some studies show that the pressure inside the thrombus is not reduced with respect to the arterial blood pressure, some, including studies from the authors, state a possible protective role [2–5]. Previously in our laboratory, a nonlinear, hyperelastic constitutive model was developed for ILT, and the parameters for which were determined through ex-vivo experimentation [8]. The purpose of this study was to investigate the reliability of using the same population-mean values of ILT constitutive parameters for estimates of wall stress distribution in all AAA. For this, we performed a parametric study in which the ELT constitutive parameters were varied within a physiological range and aortic wall stresses were evaluated.","PeriodicalId":7238,"journal":{"name":"Advances in Bioengineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91002595","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":"Applications of a Microfluidic Amplifier As a Bi-Stable Device in an Oxygen Delivery System","authors":"N. Macia","doi":"10.1115/imece2001/bed-23109","DOIUrl":"https://doi.org/10.1115/imece2001/bed-23109","url":null,"abstract":"\u0000 This paper presents the application of a planar, fluid amplifier which has been used as a bi-stable element in an intermittent, oxygen delivery device. The proportional fluid amplifier is made bi-stable by positive feedback: by connecting its outputs to its inputs, through a fluid resistor network. The fluidic fluid amplifier is the device that gave birth to the fluidics technology, in 1959, at the former Harry Diamond Laboratories (U.S. Army).","PeriodicalId":7238,"journal":{"name":"Advances in Bioengineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78184035","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":"FEA Optimization of Pedorthic Treatment for Podalgia","authors":"V. Houston, G. Luo, C. P. Mason, M. Mussman, M. Garbarini, A. C. Beattie, C. Thongpop","doi":"10.1115/imece2001/bed-23095","DOIUrl":"https://doi.org/10.1115/imece2001/bed-23095","url":null,"abstract":"\u0000 Foot problems are quite common. Epidemiological studies have shown as many as 86% of elderly individuals report having problems with their feet, ranging from calluses, cracking and ingrown nails to inflammation, swelling, ischemia, ulceration, and gangrenous necrosis [1]. Persons suffering chronic Diabetes Mellitus are at particular risk of trauma to their feet because of peripheral neuropathy, plantar fat pad and muscle atrophy, and vascular insufficiency. Half of all lower limb amputations each year in the United States are performed on diabetics because of foot and ankle injuries that fail to heal [2]. At the very least, podalgia and pedal trauma restrict person’s mobility and limit their independence, impacting their fiscal as well as their physical well-being. With the exception of memorable catastrophic events, the etiopathogenesis of podalgia and other problems contributing to pedal trauma are generally not well understood. In work with Hansen’s disease and diabetic patients, Brand et al. [3] showed that stresses as small as 1/2 psi could produce trauma in the foot fat pads of even healthy animals, if chronically and repetitively applied without adequate time for tissues to recover and rest, Pedorthic insoles (often with orthopedic shoes) are prescribed for curative as well as prophylactic treatment of podalgia and pedal trauma, especially for diabetic patients with peripheral vascular disease, and arthritic patients with osseous deformity. There are hundreds of such devices commercially available, that range in composition and mechanical characteristics from extremely soft silicone elastomers to stiff plastic and metal plates. They maybe thin or thick, flat or custom milled with precision CAD/CAM systems using 3D laser scans of the individual’s feet to match their pedal contours. Although numerous studies [4, 5, 6] have been conducted, measuring pedal plantar interface stresses, no general quantitative principles for design, performance assessment, or prescription have been developed. These procedures remain highly subjective, and quite variable, depending upon the training, experience, and skill of the patient’s pedorthotist, podiatrist, and/or physcian. The objective of this study was to investigate the stresses and strains incurred in the soft plantar tissues of the foot as a function of insole material and design geometry to enhance understanding of footwear biomechanics and contribute to development of quantitative criteria for prescription, design, and performance assessment of pedorthic footwear.","PeriodicalId":7238,"journal":{"name":"Advances in Bioengineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78741380","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of Cryoprocessing on Umbilical Cord Blood for Hematological Disorders","authors":"S. Pal, R. David","doi":"10.1115/imece2001/bed-23152","DOIUrl":"https://doi.org/10.1115/imece2001/bed-23152","url":null,"abstract":"\u0000 Cellular therapies promise to become major therapeutic modalities of this new century. The hematopoietic restoration with umbilical cord blood transplant can be a useful source of hematopoietic stem cells for routine bone marrow reconstitution. Thus it can be used as an effective source of stem cells for the treatment of various hematological disorders like leukemia, thalessaemia, aplastic anemia and it also can be used to replace the damaged tissue in various pathological conditions like Parkinson’s disease, Alzheimer’s, osteoarthritis etc. The advantage of the umbilical cord blood transplant being, use of unrelated umbilical cord blood transplantation with upto 2 to 3 HLA mismatch (Wagner et al, 1996).","PeriodicalId":7238,"journal":{"name":"Advances in Bioengineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77415747","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":"Measuring the Efficiency of Off-Road Bicycle Suspension Systems","authors":"E. Wang","doi":"10.1115/imece2001/bed-23070","DOIUrl":"https://doi.org/10.1115/imece2001/bed-23070","url":null,"abstract":"\u0000 Off-Road bicycle suspension systems are beneficial because they dissipate vibrational energy and a lower vibration dosage can reduce the metabolic energy expenditure of the cyclist [1]. However, dampers dissipate energy and the energy dissipated must be compensated by additional input from the cyclist. Estimates of the energy dissipated range from 1–2% of the total power input by the cyclist [2–4]. Additionally, suspension systems add weight to a bicycle, which also requires additional energy when hill climbing and accelerating.","PeriodicalId":7238,"journal":{"name":"Advances in Bioengineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79195747","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":"Obstruction Detection in the Upper Airways Using Input Impedance in the Frequency Domain","authors":"A. Al-Jumaily, Y. Du","doi":"10.1115/imece2001/bed-23106","DOIUrl":"https://doi.org/10.1115/imece2001/bed-23106","url":null,"abstract":"\u0000 This research focuses on establishing an appropriate theoretical technique for identifying an obstruction in a flexible compliant tube such as the trachea. The input impedance frequency spectrums for both a healthy and an obstructed airway are used as a signature to determine and examine the constriction location, severity and degree. Uniform and gradual types of constriction are considered and the results demonstrate that the input impedance resonant frequencies can map the location, severity and degree of an obstruction.","PeriodicalId":7238,"journal":{"name":"Advances in Bioengineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77962999","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":"Instability Analysis of a Cervical Spine Model Under Flexion and Compression Loading","authors":"A. Tchako, A. Sadegh","doi":"10.1115/imece2001/bed-23041","DOIUrl":"https://doi.org/10.1115/imece2001/bed-23041","url":null,"abstract":"\u0000 An improved and detailed 3-D FE model of human cervical spine was created using digitized geometric measurement. The model was validated with the in-vivo studies of Moroney, Panjabi and Fuller. Clinical instability of the spine for two cases involving flexion and compression loading (simulating injuries in motorcycle vaulting, football and diving accidents) were analyzed. The instability was based on the check list of Panjabi and White. It was determined that flexion moment of 10 Nm or compressive force of 500N result in the onset of clinical instability.","PeriodicalId":7238,"journal":{"name":"Advances in Bioengineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75351320","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}