Biomedical Engineering and Bioengineering Commons^™

A Microfluidic Pretreatment Isoelectric Focusing Dc-Field Assisted H-Filter For The Separation Of Charged Particles, Cameron Sean Carroll

Biomedical Engineering

Microfluidic devices are small portable diagnostic chips that allow for analysis of a biologic sample at relatively low cost. This makes them ideal for settings where a hospital is unavailable. The microfluidic pretreatment isoelectric focusing DC-field assisted H-filter is a device that allows for the separation of differently charged particles in a biologic sample. It does this by employing the concepts of diffusion, electrophoresis, and isoelectric focusing. This is perfect for isolation of a desired analyte or separation of waste from a sample in order to achieve better diagnostic results. The device was first modeled mathematically and visually using Comsol. …

Investigating The Reproducibility Of The Current Bvm Protocol, Corey Gross

Biomedical Engineering

Coronary Artery Disease (CAD) is responsible for 1 death every minute in the US. Angioplasty with the implantation of stents is a common treatment method for CAD. Although there is a variety of stents currently on the market, there is still a need to develop new types for different pathologic conditions. Preliminary assessment of the physiological response to new stents is needed as they are being developed. The FDA approval process implemented today is a long, tedious path with a range of testing methods that include static in vitro testing and high-cost animal testing. Tissue engineered blood vessels have been …

Tracking Knee Joint Functional Axes Through Tikhonov Filtering And Plűcker Coordinates, Wangdo Kim, Yoon-Hyuk Kim, António P. Veloso, Sean S. Kohles

Mechanical and Materials Engineering Faculty Publications and Presentations

Researchers have reported several compensation methods to estimate bone and joint position from a cluster of skin-mounted markers as influenced by Soft Tissue Artifacts (STA). Tikhonov Regularization Filtering (TRF) as a means to estimate Instantaneous Screw Axes (ISA) was introduced here as a means to reduce the displacement of a rigid body to its simplest geometric form. Recent studies have suggested that the ISA of the knee, i.e., Knee Functional Axes (KFA), might be closely connected to the estimation of constraint forces such as those due to medial and lateral connective tissues. The estimations of ISAs were known to be …

Biomedical Advancements In Injury Recovery, Performance Enhancement, And Mechanical Assistance Applied To Athletics, Matthew Russell

Biomedical Engineering

Athletics is constantly changing, and athletes are continually getting bigger, faster, and stronger. At the same time, biomedical technology and innovation is rapidly developing. New methods of injury recovery, genetic enhancement, and prosthetic assistance are being assimilated into the athletic world. The up and coming athlete needs to be aware of all of the usable information around them. This project is an accumulation of some of the cutting edge advancements in those fields. Platelet Rich Plasma Injections, Frequency Specific Microcurrent Treatment, and Silk Polymer Anterior Cruciate Ligament Replacement are innovative new ways to treat common sports injuries. Performance enhancement has …

Effects Of Ovariectomy And Anatomical Location On Osteonal Encroachment In Adult Cortical Ovine Bone, Paige Brell Ryan

Master's Theses

The purpose of this study is to further quantify adult ovine ovariectomized bone for new remodeling characteristics to obtain a better understanding of how remodeling is occurring and the effectiveness of this animal model for the study of postmenopausal osteoporosis. Postmenopausal osteoporosis is a major health concern and animal models to test new treatment options are needed. The ovine model is a good option because the ewes undergo Haversian remodeling, are a large sized animal, and have a similar hormone profile to humans. Ewes, however, do not undergo a natural menopause, so an ovariectomy surgery was conducted in the sheep …

Bacterial Growth On Metal And Non-Metal Surfaces In A Static Bioreactor, Rolan Yuk Loong Liong

Master's Theses

Research was conducted to observe bacterial growth on the surface of metals in a static bioreactor. Metal and non-metal samples were subjected to bacterial exposure (1 day and 9 days). The metal samples were surface treated prior to bacterial exposure. The microstructures of the surface treated samples were analyzed by optical microscopy. After exposure, the microstructures of the samples were analyzed by scanning electron microscopy (SEM). The analysis suggested that microbial attachment on the surface was related to the underlying microstructure of steel. The preferential attachment of microbes could potentially be influenced by cathodic and anodic regions created by the …

Mitochondrial Handling Of Excess Ca2+ Is Substrate-Dependent With Implications For Reactive Oxygen Species Generation, Mohammed Aldakkak, David F. Stowe, Ranjan K. Dash, Amadou K.S. Camara

Biomedical Engineering Faculty Research and Publications

The mitochondrial electron transport chain is the major source of reactive oxygen species (ROS) during cardiac ischemia. Several mechanisms modulate ROS production; one is mitochondrial Ca²⁺ uptake. Here we sought to elucidate the effects of extramitochondrial Ca²⁺ (e[Ca²⁺]) on ROS production (measured as H₂O₂ release) from complexes I and III. Mitochondria isolated from guinea pig hearts were preincubated with increasing concentrations of CaCl₂ and then energized with the complex I substrate Na⁺ pyruvate or the complex II substrate Na⁺ succinate. Mitochondrial H₂O₂ release rates were assessed after …

Simultaneous Measurement Of Deep Tissue Blood Flow And Oxygenation Using Noncontact Diffuse Correlation Spectroscopy Flow-Oximeter, Ting Li, Yu Lin, Yu Shang, Lian He, Chong Huang, Margaret M. Szabunio, Guoqiang Yu

Biomedical Engineering Faculty Publications

We report a novel noncontact diffuse correlation spectroscopy flow-oximeter for simultaneous quantification of relative changes in tissue blood flow (rBF) and oxygenation (Δ[oxygenation]). The noncontact probe was compared against a contact probe in tissue-like phantoms and forearm muscles (n = 10), and the dynamic trends in both rBF and Δ[oxygenation] were found to be highly correlated. However, the magnitudes of Δ[oxygenation] measured by the two probes were significantly different. Monte Carlo simulations and phantom experiments revealed that the arm curvature resulted in a significant underestimation (~-20%) for the noncontact measurements in Δ[ …

Atypical Glycolysis In Clostridium Thermocellum, Jilai Zhou, Daniel G. Olson, D. Aaron Argyros, Yu Deng, Walter M. Van Gulik, Johannes P. Van Dijken, Lee R. Lynd

Dartmouth Scholarship

Cofactor specificities of glycolytic enzymes in Clostridium thermocellum were studied with cellobiose-grown cells from batch cultures. Intracellular glucose was phosphorylated by glucokinase using GTP rather than ATP. Although phosphofructokinase typically uses ATP as a phosphoryl donor, we found only pyrophosphate (PPi)-linked activity. Phosphoglycerate kinase used both GDP and ADP as phosphoryl acceptors. In agreement with the absence of a pyruvate kinase sequence in the C. thermocellum genome, no activity of this enzyme could be detected. Also, the annotated pyruvate phosphate dikinase (ppdk) is not crucial for the generation of pyruvate from phosphoenolpyruvate (PEP), as deletion of the ppdk gene did …

Picture Of A Chelate In Exchange: The Crystal Structure Of Nahodotma, A 'Semi'-Hydrated Chelate, Katherine M. Payne, Edward J. Valente, Silvio Aime, Mauro Botta, Mark Woods

Chemistry Faculty Publications and Presentations

Crystallography generally only provides static structural information. This can render it an ineffective technique for probing dynamic solution state processes. A crystal of HoDOTMA affords unique structures that effectively represent that of a lanthanide tetra-acetate chelate mid-way through the water exchange process.

Volatility In Mrna Secondary Structure As A Design Principle For Antisense, Erik Johnson, Ranjan Srivastava

Open Access Author Fund Awardees' Articles

Designing effective antisense sequences is a formidable problem. A method for predicting efficacious antisense holds the potential to provide fundamental insight into this biophysical process. More practically, such an understanding increases the chance of successful antisense design as well as saving considerable time, money and labor. The secondary structure of an mRNA molecule is believed to be in a constant state of flux, sampling several different suboptimal states. We hypothesized that particularly volatile regions might provide better accessibility for antisense targeting. A computational framework, GenAVERT was developed to evaluate this hypothesis. GenAVERT used UNAFold and RNAforester to generate and compare …

Comparison Of A Sio2-Cao-Zno-Sro Glass Polyalkenoate Cement To Commercial Dental Materials: Glass Structure And Physical Properties, A. W. Wren, A. Coughlan, F. R. Laffir, Mark R. Towler

Chemical and Biochemical Engineering Faculty Research & Creative Works

Glass polyalkenoate cements (GPCs) have previously been considered for orthopedic applications. A Zn-GPC (BT 101) was compared to commercial GPCs (Fuji IX and Ketac Molar) which have a setting chemistry analogous to BT 101. Handling properties (working, T_w and setting, T_s times) for BT 101 were shorter than the commercial GPCs. BT 101 also had a higher setting exotherm (S_x - 34 °C) than the commercial GPCs (29 °C). The maximum strengths for BT 101, Fuji IX, and Ketac Molar were 75, 238, and 216 MPa (compressive, σ_c), and 34, 54, and 62 MPa (biaxial …

A Biomechanical Comparison Of Three Spondylolysis Repair Techniques In A Calf Spine Model, R. Roberto, B. Dezfuli, C. Deuel, S. Curtiss, S. Hazelwood

Biomedical Engineering

Summary of background data: Previous work has demonstrated the efficacy of lumbar pedicle screw hook rod (PSHR) techniques and the Buck screw in the stabilization of spondylolysis. The mechanical behavior of lower profile cervical implants used to create PSHR, hybrid cable plate constructs, and titanium miniplating has not previously been described.

Methods: Calf lumbar spines (L2-L6) were utilized for testing (n = 27). Intervertebral rotation was measured in the intact spines across the L4-5 segment before and after creation of bilateral pars interarticularis defects. Defects were then stabilized with one of three repair techniques, PSHR, miniplate, or …

Computational Fluid Dynamic Simulations For Determination Of Ventricular Workload In Aortic Arch Obstructions, Jessica S. Coogan, Frandics P. Chan, John F. Ladisa, Charles A. Taylor, Frank L. Hanley, Jeffrey A. Feinstein

Biomedical Engineering Faculty Research and Publications

Objective

The cardiac workload associated with various types of aortic obstruction was determined using computational fluid dynamic simulations.

Methods

Computed tomography image data were collected from 4 patients with 4 distinct types of aortic arch obstructions and 4 controls. The categorization of arch hypoplasia corresponded to the “A, B, C” nomenclature of arch interruption; a type “D” was added to represent diffuse arch hypoplasia. Measurements of the vessel diameter were compared against the normal measurements to determine the degree of narrowing. Three-dimensional models were created for each patient, and additional models were created for type A and B hypoplasia to …

Effect Of Fine Wire Electrode Insertion On Gait Patterns In Children With Hemiplegic Cerebral Palsy, Joseph Krzak, Daniel M. Corcos, Adam Graf, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

Background

Fine wire electromyography (EMG) is commonly used for surgical decision making in equinovarus foot deformity. However, this invasive technique may have the unwanted effect of altering the gait of children with cerebral palsy (CP). The purpose of this study was to determine if fine wire insertion into the posterior tibialis muscle affects temporal-spatial parameters and hindfoot kinematics during gait in children with equinovarus secondary to hemiplegic CP.

Methods

12 children with hemiplegic CP who presented with an equinovarus foot (mean age 12.5 yrs, four right-sided, eight left-sided) were recruited. Temporal-spatial parameters and 3-D segmental foot and ankle kinematic gait …

Protection Against Cardiac Injury By Small Ca2 +-Sensitive K+ Channels Identified In Guinea Pig Cardiac Inner Mitochondrial Membrane, David F. Stowe, Ashish K. Gadicherla, Yifan Zhou, Mohammed Aldakkak, Qunli Cheng, Wai-Meng Kwok, Ming Tao Jiang, James S. Heisner, Meiying Yang, Amadou K.S. Camara

Biomedical Engineering Faculty Research and Publications

We tested if small conductance, Ca^{2 +}‐sensitive K⁺ channels (SK_Ca) precondition hearts against ischemia reperfusion (IR) injury by improving mitochondrial (m) bioenergetics, if O₂‐derived free radicals are required to initiate protection via SK_Ca channels, and, importantly, if SK_Ca channels are present in cardiac cell inner mitochondrial membrane (IMM). NADH and FAD, superoxide (O₂⁻), and m[Ca^{2 +}] were measured in guinea pig isolated hearts by fluorescence spectrophotometry. SK_Ca and IK_Ca channel opener DCEBIO (DCEB) was given for 10 min and ended 20 min before IR. …

Long-Term Follow Up Of Van Nes Rotationplasty For Congenital Proximal Focal Femoral Deficiency, Jeffrey D. Ackman, Haluk Altiok, Ann Flanagan, Mary Peer, Adam Graf, Joseph Krzak, Sahar Hassani, Dan C. Eastwood, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

Van Nes rotationplasty may be used for patients with congenital proximal focal femoral deficiency (PFFD). The lower limb is rotated to use the ankle and foot as a functional knee joint within a prosthesis. A small series of cases was investigated to determine the long-term outcome. At a mean of 21.5 years (11 to 45) after their rotationplasty, a total of 12 prosthetic patients completed the Short-Form (SF)-36, Faces Pain Scale-Revised, Harris hip score, Oswestry back pain score and Prosthetic Evaluation Questionnaires, as did 12 age- and gender-matched normal control participants. A physical examination and gait analysis, computerised dynamic posturography …

Fabrication And Evaluation Of A Collagen-Based Fiber-Gel Three-Dimensional Construct For Peripheral Nerve Repair, Mevan Lakmal Siriwardane

Dissertations

Nerve regeneration following a peripheral nerve injury often relies on growth cone- mediated guidance and the presence of Schwann cells to support the regenerating axons and remyelinate portions of denervated nerve pathways. The emphasis of this work is to develop a synthetic nervous tissue construct that contains similar basal lamina or extracellular matrix to peripheral nerve in order to achieve a level of effectiveness in nerve repair and future peripheral nerve regeneration applications. To this end, three- dimensional nervous tissue constructs consisting of type I collagen are fabricated into a composite biomaterial scaffold to promote contact-guided growth of neuronal and …

Quantification Of Neural Substrates Of Vergence System Via Fmri, Yelda Alkan

Dissertations

Vergence eye movement is one of the oculomotor systems which allow depth perception via disconjugate movement of the eyes. Neuroimaging methods such as functional magnetic resonance imaging (fMRI) measure neural activity changes activity in the brain while subjects perform experimental tasks. A rich body of primate investigations on vergence is already established in the neurophysiology literature; on the other hand, there are a limited number of fMRI studies on neural mechanisms behind the vergence system.

The results demonstrated that vergence system shares neural sources and also shows differentiation within the boundaries of frontal eye fields (FEF) and midbrain of the …

Easily Implantable And Stable Nail-Fastener For Skeletal Fixation And Method, Patrick Atkinson, David Lecronier

Mechanical Engineering Patents

An intramedullary nail (20) defining a bore (34) is inserted into a medullary canal (26) of a bone (24). A threaded fastener (22) has a compression portion (48) presenting a compression portion diameter (D) and a threaded portion (50) present ing a threaded portion diameter (D). The fastener (22) extends through a near cortex hole (40) and/or a far cortex hole (42), and the threaded portion (22) threadedly engages the bore (34). A compression transmission device (54) is disposed between a head (44) of the fastener (22) and the intramedullary nail (20) for transmitting the compressional load of the threaded …