Biomedical Engineering and Bioengineering Commons^™

Transgenic Rat Model Of Neurodegeneration Caused By Mutation In The Tdp Gene, Hongxia Zhou, Cao Huang, Han Chen, Dian Wang, Carlisle P. Landel, Pedro Yuxing Xia, Robert Bowser, Yong-Jian Liu, Xu Gang Xia

Nebraska Center for Biotechnology: Faculty and Staff Publications

TDP-43 proteinopathies have been observed in a wide range of neurodegenerative diseases. Mutations in the gene encoding TDP-43 (i.e., TDP) have been identified in amyotrophic lateral sclerosis (ALS) and in frontotemporal lobe degeneration associated with motor neuron disease. To study the consequences of TDP mutation in an intact system, we created transgenic rats expressing normal human TDP or a mutant form of human TDP with a M337V substitution. Overexpression of mutant, but not normal, TDP caused widespread neurodegeneration that predominantly affected the motor system. TDP mutation reproduced ALS phenotypes in transgenic rats, as seen by progressive degeneration of motor neurons …

Cytocompatible Cross-Linking Of Electrospun Zein Fibers For The Development Of Water-Stable Tissue Engineering Scaffolds, Quiran Jiang, Narendra Reddy, Yiqi Yang

Department of Agricultural and Biological Systems Engineering: Faculty Publications

This paper reports a new method of cross-linking electrospun zein fibers using citric acid as a non-toxic cross-linker to enhance the water stability and cytocompatibility of zein fibers for tissue engineering and other medical applications. The electrospun structure has many advantages over other types of structures and protein-based biomaterials possess unique properties preferred for tissue engineering and other medical applications. However, ultrafine fiber matrices developed from proteins have poor mechanical properties and morphological stability in the aqueous environments required for medical applications. Efforts have been made to improve the water stability of electrospun protein scaffolds using cross-linking and other approaches, …

Microwave-Based Alkali Pretreatment Of Switchgrass And Coastal Bermudagrass For Bioethanol Production, Deepak R. Keshwani, Jay J. Cheng

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Switchgrass and coastal bermudagrass are promising lignocellulosic feedstocks for bioethanol production. However, pretreatment of lignocelluloses is required to improve production of fermentable sugars from enzymatic hydrolysis. Microwave-based alkali pretreatment of switchgrass and coastal bermudagrass was investigated in this study. Pretreatments were carried out by immersing the biomass in dilute alkali reagents and exposing the slurry to microwave radiation at 250 W for residence times ranging from 5 to 20 minutes. Simons’ stain method was used to quantify changes in biomass porosity as a result of the pretreatment. Pretreatments were evaluated based on yields of total reducing sugars, glucose, and xylose. …

Preferential Flow Effects On Subsurface Contaminant Transport In Alluvial Floodplains, Derek M. Heeren, Ron B. Miller, Garey A. Fox, Daniel E. Storm, Todd Halihan, Chad J. Penn

Department of Agricultural and Biological Systems Engineering: Faculty Publications

For sorbing contaminants, transport from upland areas to surface water systems is typically considered to be due to surface runoff, with negligible input from subsurface transport assumed. However, certain conditions can lead to an environment where subsurface transport to streams may be significant. The Ozark region, including parts of Oklahoma, Arkansas, and Missouri, is one such environment, characterized by cherty, gravelly soils and gravel bed streams. Previous research identified a preferential flow path (PFP) at an Ozark floodplain along the Barren Fork Creek in northeastern Oklahoma and demonstrated that even a sorbing contaminant, i.e., phosphorus, can be transported in significant …

Net Radiation Dynamics: Performance Of 20 Daily Net Radiation Models As Related To Model Structure And Intricacy In Two Climates, Suat Irmak, Denis Mutiibwa, José O. Payero

Department of Agricultural and Biological Systems Engineering: Faculty Publications

We compared daily net radiation (R_n) estimates from 19 methods with the ASCE‐EWRI R_n estimates in two climates: Clay Center, Nebraska (sub‐humid) and Davis, California (semi‐arid) for the calendar year. The performances of all 20 methods, including the ASCE‐EWRI R_n method, were then evaluated against R_n data measured over a non‐stressed maize canopy during two growing seasons in 2005 and 2006 at Clay Center. Methods differ in terms of inputs, structure, and equation intricacy. Most methods differ in estimating the cloudiness factor, emissivity (α), and calculating net longwave radiation (R_nl). All methods use …

Robust Dynamic Balance Of Ap-1 Transcription Factors In A Neuronal Gene Regulatory Network., Gregory M Miller, Babatunde A Ogunnaike, James S Schwaber, Rajanikanth Vadigepalli

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

BACKGROUND: The octapeptide Angiotensin II is a key hormone that acts via its receptor AT1R in the brainstem to modulate the blood pressure control circuits and thus plays a central role in the cardiac and respiratory homeostasis. This modulation occurs via activation of a complex network of signaling proteins and transcription factors, leading to changes in levels of key genes and proteins. AT1R initiated activity in the nucleus tractus solitarius (NTS), which regulates blood pressure, has been the subject of extensive molecular analysis. But the adaptive network interactions in the NTS response to AT1R, plausibly related to the development of …

Use Of A 3d Perfusion Bioreactor With Osteoblasts And Osteoblast/Endothelial Cell Co-Cultures To Improve Tissue-Engineered Bone, Matthew J. Barron

Dissertations, Master's Theses and Master's Reports - Open

The delivery of oxygen, nutrients, and the removal of waste are essential for cellular survival. Culture systems for 3D bone tissue engineering have addressed this issue by utilizing perfusion flow bioreactors that stimulate osteogenic activity through the delivery of oxygen and nutrients by low-shear fluid flow. It is also well established that bone responds to mechanical stimulation, but may desensitize under continuous loading. While perfusion flow and mechanical stimulation are used to increase cellular survival in vitro, 3D tissue-engineered constructs face additional limitations upon in vivo implantation. As it requires significant amounts of time for vascular infiltration by the host, …

Influence Of Traumatic Impaction And Pathological Loading On Knee Menisci, Megan Leigh Killian

Dissertations, Master's Theses and Master's Reports - Open

Nearly half of the US population faces the risk of developing knee osteoarthritis (OA). Both in vitro and in vivo studies can aid in a better understanding of the etiology, progression, and advancement of this debilitating disorder. The knee menisci are fibrocartilagenous structures that aid in the distribution of load, attenuation of shock, alignment and lubrication of the knee. Little is known about the biochemical and morphological changes associated with knee menisci following altered loading and traumatic impaction, and investigations are needed to further elucidate how degradation of this soft tissue advances over time. The biochemical response of porcine meniscal …

The Development Of A Mesenchymal Stem Cell Based Biphasic Osteochondral Tissue Engineered Construct, Scott Maxson

All Dissertations

The ability of human articular cartilage to respond to injury is poor. Once cartilage damage has occurred, an irreversible degenerative process can occur and will often lead to osteoarthritis (OA). An estimated 26.9 million of U.S. adults are affected by OA. Osteochondral grafting is currently used to treat OA and osteochondral defects; however, complications can develop at the donor site and defect area. Osteochondral tissue engineering provides a potential treatment option and alternative to osteochondral grafting. The long term goal of this work is to develop a tissue engineered mesenchymal stem cell (MSC) based osteochondral construct to repair cartilage damage. …

Integration Mechanisms For Heading Perception, Elif M. Sikoglu, Finnegan J. Calabro, Scott A. Beardsley, Lucia M. Vaina

Biomedical Engineering Faculty Research and Publications

Previous studies of heading perception suggest that human observers employ spatiotemporal pooling to accommodate noise in optic flow stimuli. Here, we investigated how spatial and temporal integration mechanisms are used for judgments of heading through a psychophysical experiment involving three different types of noise. Furthermore, we developed two ideal observer models to study the components of the spatial information used by observers when performing the heading task. In the psychophysical experiment, we applied three types of direction noise to optic flow stimuli to differentiate the involvement of spatial and temporal integration mechanisms. The results indicate that temporal integration mechanisms play …

The Effect Of Abductor Muscle And Anterior-Posterior Hip Contact Load Simulation On The In-Vitro Primary Stability Of A Cementless Hip Stem, Youngbae Park, Carolyne Albert, Yong-San Yoon, Göran Fernlund, Hanspeter Frei, Thomas R. Oxland

Biomedical Engineering Faculty Research and Publications

Background

In-vitro mechanical tests are commonly performed to assess pre-clinically the effect of implant design on the stability of hip endoprostheses. There is no standard protocol for these tests, and the forces applied vary between studies. This study examines the effect of the abductor force with and without application of the anterior-posterior hip contact force in the in-vitro assessment of cementless hip implant stability.

Methods

Cementless stems (VerSys Fiber Metal) were implanted in twelve composite femurs which were divided into two groups: group 1 (N = 6) was loaded with the hip contact force only, whereas group 2 (N = …

Motion Of The Multisegmental Foot In Hallux Valgus, Karl Canseco, Leah Rankine, Jason T. Long, Thomas Smedberg, Richard Marks, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

Hallux valgus is a common condition characterized by lateral deviation of the large toe and medial deviation of the first metatarsal. While some gait analyses of patients with hallux valgus have been performed using plantar pressures, very little is known about the kinematics of gait in this population. The purpose of this study was to evaluate triplanar kinematics in patients with hallux valgus using a multisegmental foot model. Materials and Methods: A 15-camera Vicon Motion Analysis System was used to evaluate the gait of 38 feet in 33 patients with mild to severe hallux valgus. The Milwaukee foot model was …

Evaluation Of Lumbosacral Orthosis In Flexion And Extension Movements Of Lumbar Spine., Norazian Abd Razak

Student Works (2010-2019)

Lumbosacral orthosis (LSO) is a type of spinal orthosis that has been recommended for abdominal support, pain management, and motion or positional control. By implemented radiographic technique, objectives of this study was to evaluate the changes of lumbar lordosis in flexion and extension of trunk movements with and without wearing the LSO measured by Cobb, Centroid, and Posterior Tangent techniques and to correlate the value of lordotic angles in particular posture. Ten healthy male subjects without any history of low back pain participated and a semi-rigid LSO was utilized. Antero-posterior and lateral radiographs of spine images during neutral, flexion, and …

Distraction Osteogenesis In An Organ Culture Model, Bradley R. Heil

University of Kentucky Master's Theses

Distraction osteogenesis (DO) is a surgical procedure in which applied strain stimulates new bone growth; however, the underlying mechanisms by which bone cells respond to load are still uncertain. An organ culture model of DO was developed and validated by using linear distraction on the femoral shafts of 5 day old Wistar rats. Two loading regimes were utilized: distracting the bones for 2 hrs on day 1 (GRP I); distracting the bones for 2 hrs on days 1, 3, and 5 (GRP II). After 1 week in culture, the bones were compared to unloaded contralateral controls and assessed for changes. …

Drug-Eluting Stents For Coronary Artery Disease: A Review, David Martin, Fergal Boyle

Articles

Over the past decade the introduction of drug-eluting stents (DESs) has revolutionised the treatment of coronary artery disease. However, in recent years concern has arisen over the long-term safety and efficacy of DESs due to the occurrence of late adverse clinical events such as stent thrombosis. With this concern in mind, research and development is currently centred on increasing the long-term safety and efficacy of DESs. The aim of this paper is to provide a thorough review of currently approved and promising investigational DESs. With dozens of companies involved in the development of new and innovative anti-restenotic agents, polymeric coatings …

Computational Structural Modelling Of Coronary Stent Deployment: A Review, David Martin, Fergal Boyle

Articles

The finite element (FE) method is a powerful investigative tool in the field of biomedical engineering, particularly in the analysis of medical devices such as coronary stents whose performance is extremely difficult to evaluate in vivo. In recent years, a number of FE studies have been carried out to simulate the deployment of coronary stents, and the results of these studies have been utilised to assess and optimise the performance of these devices. The aim of this paper is to provide a thorough review of the state-of-the-art research in this area, discussing the aims, methods and conclusions drawn from a …

Imaging The Vasculature With Susceptibility Weighted Imaging: Applications And Analysis, Samuel Barnes

Wayne State University Dissertations

Modern magnetic resonance imaging sequences allow detailed non-invasive imaging of both the arteries and veins. This work is divided into four sections that examine different applications and analysis of these sequences.

Susceptibility weighted imaging (SWI) typically generates excellent negative venous contrast. Techniques to generate positive arterial contrast in SWI images without degrading the venous contrast with a single echo are examined. By using high isotropic resolution and high readout bandwidth flow losses can be minimized (generating good arterial contrast) even at the long echo times required for good venous contrast. A downsampling filter is then used to restore lost venous …

Estimation Of 3d Shape In The Patellofemoral Joint Using Statistical Shape Models And 2d Data, Colm O'Kane

Conference Papers

Disorders of the patellofemoral joint (PFJ) including PF osteoarthritis and PF pain disorder have been estimated to represent 25% of all patients presenting for knee joint treatment. The diagnosis and treatment of these disorders is curtailed by lack of understanding of the mechanical operation of the joint. A crucial aspect to be considered in understanding contact patterns and kinematics of the PFJ is the alignment of the patella in the trochlear groove. Investigation of patellar alignment necessitates accurate knowledge of the 3D articular surfaces of both patella and femur, along with underlying bone geometry. These 3D data are generally obtained …