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Full-Text Articles in Life Sciences

Biomechanical Characterization And Modeling Of Human Tmj Disc, Gregory Wright May 2015

Biomechanical Characterization And Modeling Of Human Tmj Disc, Gregory Wright

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Temporomandibular joint (TMJ) disorder affects over 10 million people in the US each year. The signs and symptoms of temporomandibular joint disorders (TMDs) include limited mouth opening, clicking and locking of the jaw, and significant pain in the craniofacial region. In patients who seek treatment for TMDs, over 70% have TMJ disc displacement related to disc degeneration. The TMJ disc is interposed between the mandible condyle and the glenoid fossa of the temporal bone. The disc reduces contact stresses within the joint and provides lubrication to the joint. It is generally believed that pathological mechanical loadings, such as sustained jaw …


Contra-Compartmental Joint Mechanics In Unicondylar Knee Arthroplasty, Roy Rusly Apr 2015

Contra-Compartmental Joint Mechanics In Unicondylar Knee Arthroplasty, Roy Rusly

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Recently, unicondylar knee arthroplasty (UKA) has seen a resurgence in clinical popularity, due to its increased success rate, improvement in implant designs, and more efficient surgical techniques. However, it continues to be a more technically demanding procedure and less forgiving compared to TKA [14,16-19]. The early reported failures due to the malalignment errors during surgery remain areas of concern clinically and experimentally [41-44,46]. In addition, the difference in the compliance between the UKA implant materials (metal-polymer) and the soft tissues in the un-operated comparted could also affect the load distribution on the knee joint. Advancement in medical technology and improvement …


Investigating The Effects Of Biochemical And Biophysical Signals On Vascular Smooth Muscle Cell Differentiation, Ruikai Chen Dec 2014

Investigating The Effects Of Biochemical And Biophysical Signals On Vascular Smooth Muscle Cell Differentiation, Ruikai Chen

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In blood vessel engineering, an optimal bioartifical scaffold can be characterized as a 3D tubular structure with high porosity for nutrient diffusion and enough mechanical strength to sustain in vivo dynamic environment. The luminal surface of the scaffold is supposed to have a continuous layer of endothelial cell that is ideally non-immunogenic and non-thrombogenic while the media layer of the construct is assigned for the ingrowth of vascular smooth muscle cell which can provide structural integrity and contractility. While reconstructing endothelial cell layer has been at the center of interest in most polymeric vascular replacements related research, growing VSMCs has …


Evaluation Of The Functional Capabilities Of Fins And Limbs For Moving On Land: Insights Into The Invasion Of Land By Tetrapods, Sandy Kawano Aug 2014

Evaluation Of The Functional Capabilities Of Fins And Limbs For Moving On Land: Insights Into The Invasion Of Land By Tetrapods, Sandy Kawano

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Transitions to novel habitats present different adaptive challenges, producing captivating examples of how functional innovations of the musculoskeletal system influence phenotypic divergence and adaptive radiations. One intriguing example is the transition from aquatic fishes to tetrapods. Recent technological advances and discoveries of critical fossils have catapulted our understanding on how fishes gave rise to terrestrial vertebrates. Considerable attention has been paid to legged locomotion on land, but given that the first tetrapods were aquatic, limbs did not evolve primarily for terrestriality. How, then, is the locomotor function of limbs different from fins? Extant amphibious fishes demonstrate that fins can be …


Humeral Torsion And Shoulder Biomechanics: Comparison Of A Novel Ultrasonographic Technique With The Computed Tomography Benchmark, Bryan Thurston May 2013

Humeral Torsion And Shoulder Biomechanics: Comparison Of A Novel Ultrasonographic Technique With The Computed Tomography Benchmark, Bryan Thurston

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The rotation angle between the proximal and distal axes of long bones is known as torsion, and it is thought to be indicative of the forces applied to the bone during growth. The humerus, for example, develops an internal twist or antetorsion, as daily activities are anterior to the body. However, the strong posterior stress induced by an overhead throwing motion may counteract this internal twist in young athletes and cause prominent bilateral dimorphism.
To measure torsion in these young athletes, a new technique using ultrasound has been developed and implemented in clinical practice. However, before widespread use in diverse …


Integrating Biomechanics And Cell Physiology To Understanding Ivd Nutrition And Cell Homeostasis, Yongren Wu May 2013

Integrating Biomechanics And Cell Physiology To Understanding Ivd Nutrition And Cell Homeostasis, Yongren Wu

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Back pain associated with degeneration of the intervertebral disc (IVD) is a major public health problem in Western industrialized societies. Degeneration of the IVD changes the osmotic and nutrient environment in the extracellular matrix (ECM) which affects cell behaviors, including: cell proliferation, cell energy metabolism, and matrix synthesis. In addition, a thin layer of hyaline cartilaginous end-plate (CEP) at the superior/inferior disc-vertebral interface was found to play an important role in nutrient supply as well as load distribution in the IVD. Therefore, our general hypothesis is that the CEP regulates the ECM osmotic and nutrient environment which further affects IVD …


Biomechanical Testing Of Salter-Harris Fractures Type I And Ii In The Distal Femur And Proximal Tibia, Margeaux Rogers May 2013

Biomechanical Testing Of Salter-Harris Fractures Type I And Ii In The Distal Femur And Proximal Tibia, Margeaux Rogers

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Salter-Harris fractures of the proximal tibia and distal femur are common in pediatric patients that present to orthopedic surgeons. Salter-Harris type I fractures are characterized by breaks that extend only through the physis while Salter-Harris II fractures are the most common, accounting for 85% of Salter-Harris fractures, and extend past the growth plate, exiting through the metaphyseal bone1. Fixation of these fracture types can be accomplished using a variety of methods including the use of Kirschner wires, cannulated screws, and a combination of both materials. Stability of fracture fixation is of utmost importance as persistent motion at the fracture margin …


Computational Approaches To Understand Phenotypic Structure And Constitutive Mechanics Relationships Of Single Cells, Scott Wood Dec 2011

Computational Approaches To Understand Phenotypic Structure And Constitutive Mechanics Relationships Of Single Cells, Scott Wood

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The goal of this work is to better understand the relationship between the structure and function of biological cells by simulating their nonlinear mechanical behavior under static and dynamic loading using image structure-based finite element modeling (FEM). Vascular smooth muscle cells (VSMCs) are chosen for this study due to the strong correlation of the geometric arrangement of their structural components on their mechanical behavior and the implications of that behavior on diseases such as atherosclerosis.
VSMCs are modeled here using a linear elastic material model together with truss elements, which simulate the cytoskeletal fiber network that provides the cells with …


Comparative Forelimb Muscle Function In Turtles: Tests Of Environmental Variation And Neuromotor Conservation, Angela Rivera May 2011

Comparative Forelimb Muscle Function In Turtles: Tests Of Environmental Variation And Neuromotor Conservation, Angela Rivera

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Novel locomotor functions in animals may evolve through changes in morphology, muscle activity, or a combination of both. The idea that new functions or behaviors can arise solely through changes in structure, without concurrent changes in the patterns of muscle activity that control movement of those structures, has been formalized as the `neuromotor conservation hypothesis'. In vertebrate locomotor systems, evidence for neuromotor conservation is found across transitions in terrestrial species and into fliers, but transitions in aquatic species have received little comparable study to determine if changes in morphology and muscle function were coordinated through the evolution of new locomotor …


Electromechanics Of Biological Systems Studied By Scanning Probe Microscopy, Gary Thompson May 2011

Electromechanics Of Biological Systems Studied By Scanning Probe Microscopy, Gary Thompson

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The functional role of piezoelectricity and of other modes of electromechanical coupling across the hierarchical structures of biological materials garnered interest many years ago. Many biological materials have been described as exhibiting piezoelectric behavior, from wool fibers to wood planks and even to living mammalian cells, but efforts are on-going towards understanding how electromechanical coupling in biological systems transcends from the molecular to tissue levels.
In pursuit of high-resolution measurements of such hierarchical electromechanical coupling, scanning probe microscopy-based techniques are considered. Piezoresponse force microscopy (PFM) becomes the specific focus of this work, and the nascent development of PFM is reviewed …


Femoral Loading Mechanics In Virginia Opossums (Didelphis Virginiana): Torsion And Mediolateral Bending In Mammalian Parasagittal Locomotion, William Gosnell Dec 2010

Femoral Loading Mechanics In Virginia Opossums (Didelphis Virginiana): Torsion And Mediolateral Bending In Mammalian Parasagittal Locomotion, William Gosnell

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Studies of limb bone loading in terrestrial mammals have typically found anteroposterior bending to be the primary loading regime, with torsion contributing minimally. However, previous studies have focused on large, cursorial eutherian species in which the limbs are held essentially upright. Recent in vivo strain data from the Virginia opossum Didelphis virginiana, a marsupial that uses a crouched rather than upright limb posture, have indicated that its femur experiences moderate torsion during locomotion as well as strong mediolateral bending. The elevated femoral torsion and strong mediolateral bending observed in opossums (compared to other mammals) might result from external forces such …


We're Here Now: An Exploratory Study Of The Relationships Between Tourism And Post-Migration Community Participation And Sense Of Community, Jason Draper Dec 2009

We're Here Now: An Exploratory Study Of The Relationships Between Tourism And Post-Migration Community Participation And Sense Of Community, Jason Draper

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ABSTRACT
Research has suggested that visiting a community can result in an inclination (Cuba, 1989) or likelihood of moving there (McHugh, 1990). One reason that may contribute to the decision to move is tourism experiences provide an opportunity for visitors to compare the destination to their current community and determine if voids that exist would be filled should they relocate (Haug, Dann, & Mehmetoglu, 2007). However, should tourists decide to relocate, research is needed that examines how tourists transition to being a resident (Oigenblick & Kirschenbaum, 2002) and policy implications of residential growth. The purpose of this exploratory study was …


Physical Activity Among Youth In A Weekend Respite Camp Program, Kathleen Felton Dec 2009

Physical Activity Among Youth In A Weekend Respite Camp Program, Kathleen Felton

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The engagement in physical activity among 24 youths with disabilities was studied. Researchers examined the effects of age and gender of the youth, the parent's knowledge of physical activity recommendations, and parent's physical activity practices on physical activity engagement. Levels of physical activity participation through leisure time, work or chores, and sports were assessed. Analysis was performed to determine relationships between each of the variables and the youths' level of physical activity respectively. Results of chi-square analysis indicated that parental influence using current physical activity recommendations was correlated with the youth's level of physical activity participation through leisure. Results suggested …