bluuebunny/crossref_metadata_2025_split huggingface dataset:
Delivering a Safe and Effective Cellular Product
Authors: Schaeffer Susan 
Published: November 2021

Abstract
Apligraf® is a viable, bi-layered skin construct containing purified Type I bovine collagen and viable allogeneic human fibroblast and keratinocyte cells isolated from infant foreskin tissue. It is classified as a medical device in the United States and has been shown to be safe and effective in the treatment of venous stasis ulcers. Production of a living skin tissue presents unique challenges because of the number of diverse raw materials involved in its manufacture. Critical components such as collagen, cell banks, serum and media supplements are subjected to rigorous and costly testing to ensure that they are free of pathogens and impurities. Approaches to the quality challenges presented in the manufacture of Apligraf® will be discussed below.
Microstructural Factors in Neocartilage Function
Authors: Lewis Jack L. 
Published: November 2021

Abstract
Tissue engineering of cartilage and other connective tissues is a highly active area of research, motivated by the considerable medical need and commercial potential. Tissue with biological properties and biochemical composition similar to cartilage have been generated in laboratory cultures and animal models, and one method is being used in patients. Throughout the early development of regenerated cartilage, the focus has been on getting something to grow that is biochemically like cartilage and fills defects with tissue that visually looks like cartilage and holds up mechanically over the short term. The issues of cell source, culturing conditions, and scaffolds have also been addressed. However, all of the tissues generated have structure and microstructural organization that are not like natural cartilage. Although the clinical performance of the regenerated tissue appears promising, experience with prior regenerated tissue and the fact that the tissue is abnormal gives concern about the long term performance of the regenerated cartilage and the influence of activity level on this performance. Its long term mechanical properties are suspected to be inadequate. Future developments in this area will need to both enhance the mechanical characteristics of the regenerated tissue and develop methods and criteria for evaluating the tissue that is generated. Our work on matrix assembly by chondrocytes has been directed towards these ends. The goal has been to understand the microstructural basis for mechanical properties in tissue generated by chondrocytes in culture, develop methods to alter and control the microstructure, and build both experimental and theoretical models that allow evaluating the connection between microstructure and macroscopic properties. This is similar to a materials science approach which, we believe, will be one approach to the second generation of engineered tissues. The approach and results to date on tissue generated by chondrocytes will be described in this presentation. A specific question related to collagen network microstructure will be used to illustrate this approach.
Biocompatible Scaffolds for Engineered Arteries
Authors: Niklason L. E. , DuLaney T. V. , Moats A. K. , Mitchell S. , Prabhakar V. 
Published: November 2021

Abstract
Because of the tremendous clinical need for small caliber (&lt; 6 mm diameter) arterial replacements, multiple approaches have been developed to culture biological arterial grafts both in vivo and in vitro. We have developed an approach that utilizes autologous smooth muscle and endothelial cells that are expanded in culture and then seeded onto rapidly degrading polyglycolic acid (PGA) scaffolds. The seeded tubular scaffolds are cultured under conditions of pulsatile radial stress to simulate the native hemodynamic environment. However, the effects of the type of culture scaffold on the phenotype and properties of tissue engineered vessels has not been investigated.
Materials Processing Technology for an Acellular Artificial Skin
Authors: Cahn Frederick 
Published: November 2021

Abstract
Artificial skin is a bilayer skin replacement system designed to regenerate dermal tissue. Prior to the commercial availability of artificial skin, surgically created wounds that cannot be closed by primary means (such as excising deep partial or full-thickness burns), had to be treated with autograft; a graft of the patient’s own skin harvested from a healthy donor site. This is because the dermal layer of skin cannot regenerate functional tissue spontaneously; instead, scar tissue forms. When applied surgically to a clean, excised wound bed, autograft becomes permanently engrafted, that is, it becomes permanently affixed to the underlying tissue and vascularized. However, autograft has serious drawbacks, including the creation of a donor wound, which has its own significant morbidity, and its unavailability in sufficient quantity in patients with large wounds.
Towards a Mechanism for Bioprosthetic Valve Failure
Authors: Vesely Ivan , Barber J. Edward , Mako W. John , Ratliff Norman B. 
Published: November 2021

Abstract
Porcine bioprosthetic valves are commonly used to replace the native cardiac valves when they become diseased and dysfunctional. One class of bioprosthesis consists of whole pig aortic valves, tanned in glutaraldehyde and mounted on plastic or wire frames. These devices work very well in the short term (&lt; 5 years) but eventually begin to fail gradually and typically do not last more than 15 years [1]. Many have tried to elucidate a mechanism of bioprosthetic valve failure, but little progress has been made, until recently. Historically, calcification has been thought to be the primary mechanism of bioprosthetic valve failure [2]. Recently, however, it has become recognized that mechanical damage to bioprosthetic valves can occur independently from calcification [3]. This shift in opinion has been supported by a number of observations. For example, Purinya et. al. [4] have shown that after four years of implantation, bioprosthetic valve explants have lower failure stresses and fail at greater strains than fresh porcine bioprostheses. Similar observations have been made in valves fatigued in vitro [5]. Others have shown that these mechanical changes are accompanied by biochemical changes in the collagen fibers [6]. We have shown previously in preliminary studies that glycosaminoglycans (GAGs) are lost from implanted bioprosthetic valves [7]. Since GAGs are responsible for maintaining tissue viscoelasticity, loss of GAGs would have detrimental effects on tissue mechanics. In separate studies, we have demonstrated that damage to elastin can also have detrimental effects on tissue mechanics, and on valve durability as a whole [8].
Large Displacement Flexural Properties of Tissue Engineered Heart Valve Scaffolds
Authors: Sacks Michael S. , Kaushal Sanjay , Mayer John E. 
Published: November 2021

Abstract
The need for improved heart valve prostheses is especially critical in pediatric applications, where growth and remodeling are essential. Tissue engineered heart valves (TEHV) have functioned in the pulmonary circulation of growing lambs for up to four months [1], and thus can potentially overcome limitations of current bioprosthetic heart valves. Despite these promising results, significant questions remain. In particular, the role of scaffold mechanical properties in optimal extra-cellular matrix development, as well as TEHV durability, are largely unexplored. We have previously demonstrated flexure testing as a sensitive and critical test for BHV tissue mechanical property evaluation [2]. The following study was conducted to determine the feasibility of using this technique to provide fundamental information required for optimizing TEHV scaffold designs.
Flow-Dependent Luminal Deposition of Microspheres in Porcine Carotid Arteries Ex Vivo
Authors: Enyinna Onyekachi C. , Chesler Naomi C. 
Published: November 2021

Abstract
Throughout the cardiovascular system, blood flow and pressure are unsteady and pulsatile, with oscillatory (zero-mean) flow in areas of bends and bifurcations (Ku 1997). Resulting hemodynamic forces have been proposed as a controlling factor for arterial wall permeability to atherogenic proteins such as low density lipoprotein (LDL). For example, Meyer et al. found that increased transmural pressure decreased LDL entrapment in the arterial media, and Lever and coworkers found that LDL entrapment was increased when stretching was prohibited by a restraining collar (Lever, et al. 1996; Meyer, et al. 1996).
A Device for Evaluating Laxity of the Thumb Carpometacarpal Joint
Authors: Soltz Michael A. , Koff Mathew F. , Balaguer Eric J. , Pawluk Robert J. , Strauch Robert J. , Rosenwasser Melvin P. , Ateshian Gerard A. , Mow Van C. 
Published: November 2021

Abstract
It has been proposed that ligamentous laxity promotes osteoarthritis of the thumb carpometacarpal joint. However, quantitative measurements of laxity for this joint have not been correlated with its incidence of osteoarthritis nor with other measures of degenerative changes such as joint congruence, surface remodeling, cartilage mechanical properties or biochemical composition. The goal of this study was to design and build a device for testing the laxity of the carpometacarpal joint, with the long-term aim of advancing our understanding of the etiology of osteoarthritis in this joint. This laxity tester has the ability to accurately measure the force-displacement response along the joint’s dorsal-volar, radial-ulnar, and distraction-reduction directions, as well as the torque-rotation response in pronation-supination. The compliance of the tester was evaluated and laxity curves were generated for a sample thumb carpometacarpal joint.
An Experimental Methodology to Evaluate the Rigidity of Penile Prostheses in Vitro
Authors: Wang Shyh-Jen 
Published: November 2021

Abstract
This work investigates the hardness and buckling force of penile prosthesis to further understand the rigidity of penile prosthesis before and after implantation. Evaluated herein are four prosthetic samples (inflatable 3, semi-rigid 1), five realities (inflatable 1, semi-rigid 4), and one after implantation of prosthesis. The hardness is measured with a hardness tester by pressing the tester’s indentor to the surface of the specimen. In addition, a patient after implantation is evaluated with respect to the hardness of penile versus various numbers of pumping. The buckling force of the prosthesis is also determined by a push-pull gauge and special designed sampling table. Results in this study demonstrate that although the inflatable prosthesis could only be pumped to a certain amount of hardness, hardness and buckling force correlate well with each other. After reaching the extreme hardness, prostheses can even be further pumped a few times. However, continuous pumping only puts more tension on the prosthetic material without increasing any hardness and could induce to mechanical failure of prosthesis. Results also indicate that the buckling force decreases with increasing length of the semi-rigid prostheses, and, then, enlarged when the prosthesis has a larger diameter. This in vitro non-invasive mechanical measurement of the rigidity in penile prosthesis can provide not only clinicians with further information about the penile prosthesis before implantation, but also the patients with more confidence in the prosthesis usage after implantation.
Stress-Dependent Effects of Platelet-Derived Growth Factor-BB on Fibroblast Migration and Traction Differ in Collagen and Fibrin
Authors: Shreiber David I. , Enever Paul A. J. , Tranquillo Robert T. 
Published: November 2021

Abstract
We used our novel assays of cell behavior in tissue equivalents to study the dose-response effects of PDGF-BB on RDF migration and traction in mechanically stressed and stress-free type I collagen and fibrin gels. PDGF-BB increased fibroblast migration significantly in all assays, but the effects on traction depended on the presence of stress and the nature of the ECM. PDGF-BB decreased fibroblast traction in stressed collagen gels, but increased traction in stress-free gels. No statistical conclusion could be inferred for stressed fibrin gels, and increasing PDGF-BB decreased traction in stress-free fibrin gels. These results demonstrate the complex response of fibroblasts to environmental cues, and point to opportunities to orchestrate cell behavior to affect the outcome of wound healing.
Fracture Patterns and Strain Information in Thoracolumbar Burst Fractures
Authors: Langrana Noshir A. , Harten Robert D. , Lin David C. , Reiter Mitchell F. , Lee Casey K. 
Published: November 2021

Abstract
A combined loading of axial compression and anterior shear on a spinal motion segment causes the severe form of burst fracture. Thoracolumbar motion segments were instrumented with a strain gage on the middle of the anterior wall and one near the base of the pedicles. Two samples were subjected to high-speed axial compression in the neutral position while two were tested in extension to maximize facet joint loading. The specimens tested in extension exhibited the more severe fracture pattern, indicated by failure of the middle column and an increase in interpedicular distance. Failure loads and ratio of strain at the base of the pedicles to strain at the anterior wall were higher in this group. The results suggest that the shear force transmitted through the facet joint and the pedicles to the posterior upper half of the vertebral body is an essential component of the injury mechanism.
Characterization of Porosity and Pore Size Distribution Changes in Human Compact Bone by Low-Field NMR
Authors: Ni Qingwen , King J. Derwin , Wang Xiaodu 
Published: November 2021

Abstract
Previous studies have shown that the overall porosity of bone has a significant effect on the mechanical strength of bone. In a comprehensive review on porosity of bone, Martin [1] described that small changes in porosity would lead to significant changes in the stiffness and strength of both compact and spongy bone. In a recently study, McCalden [2], reported that the porosity of bone has a significant effect to absorb energy during fracture. Since changes in numbers and sizes of these natural cavities are directly related to the remodeling processes and biomechanical properties of bone, a direct sensing technique to detect such changes in bone has been long wanted.
The Inspiratory and Expiratory Flow in Distensible Tracheostenosis Model
Authors: Sera Toshihiro , Satoh Sunao , Horinouchi Hirohisa , Kobayashi Kohichi , Tanishita Kazuo 
Published: November 2021

Abstract
To identify the possible mechanism of wheeze generation in the tracheostenosis, we measured the inspiratory and expiratory flow in the realistic model reconstructed based on CT data of patient. Trachea consists of tracheal cartilage rings and smooth muscle, which influence the localized variation of distensibility of model airway. The localized variation of distensibility was achieved by the varied thickness of silicone rubber based on the elastic modulus measured for the pig airway. The Reynolds number was 1100, and both inspiratory and expiratory flow were disturbed by the stenosis. The turbulence intensity for the distensible model is moderated compared the rigid model.
Development of Biomechanical Cervical Spine Physical Models
Authors: Milkowski Lisa M. , Crockett Robert S. , Kumaresan Srirangam 
Published: November 2021

Abstract
A methodology using rapid prototyping (RP) to produce discrete-region and continuous gradients in material mixtures to represent cervical spine vertebra is presented. Composites are created by using a RP lattice pattern as a host for filler materials. With additional process steps to replace the RP lattice epoxy, composites are also created with two different matrix materials creating differing local property regions. The internal structure thickness of the lattice pattern is varied in a continuous manner to produce composites ranging from the host material to the filler material. Results from initial samples are presented.
Three-Dimensional Woven Composite Materials for Impact Protection: Application to Soccer Shin Guards
Authors: Francisco Anthony C. , Leung Jeffrey C. , Moutos Franklin T. , Guilak Farshid 
Published: November 2021

Abstract
Soccer shin guards have been shown to provide significant protection against minor injuries such as scrapes and contusions. However, several studies suggest that serious injuries such as tibia fractures may still occur despite the use of shin guards [1]. The majority (79%) of such fractures are minimally displaced, suggesting that the injuring impacts are slightly above the fracture tolerance of bone [1]. In this respect, shin guards with improved impact properties may be able to decrease the risk of serious injuries in soccer. Impact testing of shin guards has shown that some designs and materials provide better protection than others [2]. Generally, a shin guard reduces impact by using a stiff shell over which to distribute the impact and a compliant material that absorbs impact energy. Unfortunately, the protective physical characteristics of guards correlate best with increased weight and thickness, factors that conflict with players’ preferences for lighter, more comfortable guards.
Inverse Estimation of the In Vivo Mechanical Properties of the Human Cornea
Authors: Chang Shou-sung , Pinsky Peter M. 
Published: November 2021

Abstract
Various forms of refractive surgery for vision correction have come into clinical practice in which the corneal tissue is either incised, removed, added to, or redistributed. The outcomes of these procedures must be to a large extent determined by the intrinsic mechanical properties of the major structural layer of the cornea, the stroma1. If these mechanical properties, principally the Young’s modulus and shear modulus, are established for the human cornea, it will be possible to include them in a finite element model of the stroma that can help predict the outcome of keratorefractive procedures. In this study an opto-mechanical testing device was developed to measure the contour of a cornea deformed in situ by a mechanical probe. A nonlinear finite element model of the cornea was then constructed to simulate the experiment for use in inverse estimation of the in vivo Young’s and shear moduli of an individual eye.
Sensitivity to Pore Geometry of Virus Transmission Through Latex Channels: Experimental Analysis
Authors: Myers Matthew R. , Lytle C. David , Routson Licia B. 
Published: November 2021

Abstract
Previously published measurements of virus transmission through a channel comprised of two planar sheets of latex material displayed an unexpectedly high transmission rate for large virus residence times in the channel. Additional experiments demonstrated that the elevated transmission rate can be explained as a high sensitivity of virus transport to perturbations in channel geometry, for highly adsorptive viruses.
Effect of Flow Rate on Properties of Resin Transfer Molded Disks
Authors: Olivero Kristian A. , Fuller Randal E. , Dhillon Inderbir S. , Altan M. Cengiz 
Published: November 2021

Abstract
The effect of flow rate on the mechanical properties of resin transfer molded disks is experimentally investigated. An experimental molding setup is constructed to fabricate fiber-reinforced, center-gated, disk-shaped composite parts. Disks are molded at different flow rates in order to observe the effect of this parameter on the mechanical properties of the final parts. Specimens are cut from different sections of the molded disks, and tested for strength and stiffness. Strength and stiffness are found to vary exponentially based on the maximum local fluid velocity during filling. Increased local velocity is found to reduce both the strength and stiffness of the molded parts due to increased voids induced by the faster moving fluid front.
Probabilistic Characterization of Fatigue Damage Data for Aerospace Materials
Authors: Orisamolu I. R. Wally 
Published: November 2021

Abstract
The development of stochastic models for representing the uncertainties present in a problem is a very important component of probabilistic reliability analysis. Stochastic modeling of engineering parameters require the determination of appropriate probability distribution functions and their associated statistical parameters. In cases that of practical interest, there are usually two or more random variables or processes involved, and hence it is further necessary to establish the correlations between the uncertain parameters or functions. The choice of stochastic models often influences the reliability values as well as the probabilistic sensitivity factors computed from analyses. This is especially so for probabilistic fracture mechanics and fatigue reliability calculations which constitute the cornerstone for durability and damage tolerance assessments.
The present paper reports the development of a methodology for probabilistic fatigue data characterization. The characterization utilizes raw fatigue damage (crack initiation or crack growth) data to determine the most appropriate probability distributions, statistical parameters and confidence bounds for the modeling parameters that are involved in fatigue damage initiation and propagation relations used in durability and damage tolerance prediction. Correlations between different parameters are also computed on the basis of well established deterministic models and standards (such as the ASTM E647-93 standard) that have been widely accepted in the industry. Statistical tests are implemented on the basis of Kolmogorov-Smirnov measures of model acceptability. The probabilistic models are determined using both the method of moments (MOM) and maximum likelihood estimators (MLE) and are packaged within the framework of a user-friendly computational tool (PRADAC). Illustrative practical examples are presented to demonstrate the utility of this probabilistic pre-processing computational tool and the important effects on fatigue reliability prediction of aerospace structural components.