Engineering Commons^™

Infrared Light Activated Floating Micro Stimulators For Neuro-Prosthetic Applications, Kimberlyn M. Gray

Doctoral Dissertations

The most common failures in neural stimulation implants are due to interconnect complications such as tissue response, lead migration, and lead breakages. The challenge in eliminating interconnects lies in minimizing device size to maintain spatial selectivity required in the CNS. One approach to this problem is a current generating device that can be stimulated by an external signal, such as light or sound. Here, we report the design, construction and testing of rnicrophotodiode devices that can be stimulated remotely with near-infrared (NIR) light to generate current that can be injected locally into the peripheral nervous system. The use of near-infrared …

Advances In Helical Stent Design And Fabrication: Studies Of Stent Thermal Treatment, Stent Mechanical Properties, And Stent Interactions With A Simulated Plaque-Laden Artery, Tre Raymond Welch

Bioengineering Dissertations - Archive

Advancements in processing biomaterials have lead to the development of bioresorbable PLLA drug-loaded stents with different geometric configurations. To further advance the technology, systematic studies have been carried out. This dissertation consists of six specific aims: 1) To characterize the effects of thermal annealing on the mechanical characteristics of PLLA helical stent, 2) To characterize the mechanical characteristics of a PLLA double helix stent, 3) To characterize the physical and chemical properties of PLLA films impregnated with niacin and curcumin, 4) To characterize the mechanical interaction of expanded stent and vascular wall with both model simulation and experimental studies using …

Functional Near Infrared Spectroscopy For The Assessment Of Motor Cortex Plasticity In Pediatric Subjects Affected By Cerebral Palsy, Bilal Khan

Bioengineering Theses - Archive

Functional near infrared spectroscopy (fNIRS) is widely used to monitor hemodynamic changes occurring in the cerebral cortex as a result of neuronal activation. One of the current challenges in this field is that activation-related hemodynamic signals are often eclipsed by global hemodynamic fluctuations due to cardiac pulsation, respiration and Mayer waves. In this study, we demonstrate by using a combination of principal component analysis (PCA) and adaptive filtering that the global hemodynamic modulation signals can be effectively removed from the fNIRS measuring cortical hemodynamic response. While pediatric subjects were performing a finger tapping task, we concurrently recorded cardiac pulsation and …

Spatiotemporal Measurement Of Freezing-Induced Deformation Of Engineered Tissues, Ka Yaw Teo

Bioengineering Theses - Archive

In order to cryopreserve functional engineered tissues (ETs), the microstructure of extracellular matrix (ECM) as well as the cellular viability should be maintained given that the functionality of ETs is closely related to the ECM microstructure. Since the post-thaw ECM microstructure is determined by the deformation of ETs during cryopreservation, the freezing-induced deformation of ETs was measured in the present study with a newly developed quantum dot (QD)-mediated cell image deformetry technique using dermal equivalents as a model system. The dermal equivalents were constructed by seeding QD-labeled fibroblasts in type I collagen matrices. After 24 hour incubation, the ETs were …

Development Of Microscope Stage Incubator For Long-Term Monitoring Of Neuronal Cell Culture During Axotomy, Kailash Karthikeyan

Bioengineering Theses - Archive

It is imperative to understand the patterns in regeneration of the central and peripheral nervous system after injury. This understanding would provide a fundamental cue towards molecules and other factors involved in regeneration, and how they affect the regeneration pattern after injury. In most culturing techniques currently used for neuronal culturing and observing the neuronal regeneration, it is difficult to determine the regeneration pattern (individual axonal level) though the overall regeneration is observed due to the complexity of neuronal network. Thus a model that provides isolation of individual axons and allowing us to monitor continuously upon injury has been developed. …

Controlled Vascular Cellular Growth By Microstructured Patterned Surfaces On Implantable Biodegradable Polymer Scaffold., Nitin Garg

Bioengineering Theses - Archive

The technological advances in the field of MEMS and biodegradable polymers with elastomeric properties have opened new areas of application for engineering of soft tissues such as blood vessel, heart valves, cartilage, tendon, and bladder, which exhibit elastic properties. In this thesis work, Microfabrication technology has successfully been applied to biodegradable polymer films to encourage cell growth in designated area. This work is presented with the final goal of fabricating implantable polymer scaffolds to produce small diameter blood vessels in a controlled manner spatially by using the concept of wettability and contact guidance.There are several methods to control cell growth …

Molecular Modelling Of Dna Translocation In Bio-Functionalized Nanopores With Applications In Gene Sequencing, Abhijit Ramachandran

Bioengineering Theses - Archive

The human genome project which was completed in 2003 took more than 12 years to complete at a cost of $2.7 billion. The advancement in technologies in the next five years led to the same feat being achieved in 5 months with a total cost of $1.5 million. Micro-fabrication technology has now made it possible miniaturize to micro- and nanofluidic devices for biochemical analysis. Solid-state nanopore based molecular analysis provides the potential to characterize and sequence DNA, based on the signature of the ionic current measured. A major challenge in using solid-state nanopores for DNA detection and sequencing is the …

Effects Of Cyclic Strain And Growth Factors On Vascular Smooth Muscle Cell Responses, Kytai Truong Nguyen, Hao Xu

Bioengineering Faculty Publications - Archive

Under physiological and pathological conditions, vascular smooth muscle cells (SMC) are exposed to different biochemical factors and biomechanical forces. Previous studies pertaining to SMC responses have not investigated the effects of both factors on SMCs. Thus, in our research we investigated the combined effects of growth factors like bFGF (basic fibroblast growth factor), TGF-�� (transforming growth factor ��) and PDGF (platelet-derived growth factor) along with physiological cyclic strain on SMC responses. Physiological cyclic strain (10% strain) significantly reduced SMC proliferation compared to static controls while addition of growth factors bFGF, TGF-�� or PDGF-AB had a positive influence on SMC growth …

Dlp Hyperspectral Imaging For Surgical And Clinical Utility, Robert Paul Francis

Bioengineering Theses - Archive

Surgeons want technology to help them see differences in tissue chemistry. If they know how oxygenated tissues and organs are during medical procedures, they are more able to eliminate dangerous tissues and maintain viable organs. Hyperspectral imaging non-invasively measures the optical absorbance spectrum of each pixel in a spatial field of view and, with chemometric image processing, can visualize the spatial distribution of tissue oxygenation. Current hyperspectral imaging systems are too slow to monitor real-time physiological changes in live tissue. Therefore, a novel DLP Hyperspectral Imaging (DLP HSI) system is developed for real-time, non-invasive, in-vivo imaging of tissue chemistry in …

A Novel Device For The Establishment Of An Animal Model Mimicking Spinal Deformity Surgery For Neurological Deficit Risk Mitigation, Bradley Elmer

Bioengineering Theses - Archive

Correction forces during spine deformity surgery impart significant multidirectional stress forces to the spinal cord, which in some cases result in severe damage to the spinal cord and permanent paralysis, the most feared complication. Animal models are critical for the development of neuroprotective strategies. However, those currently available are limited to contusion, transection, or unidirectional distraction injuries, which fail to replicate the multidirectional forces that occur during spine corrective surgery. In order to develop an improved model of distraction spinal cord injury we designed a device based on intervertebral grip fixation and linear actuators, capable of inducing controllable bidirectional distraction …

In Situ Crosslinkable Polyesters For Tissue Engineering And Drug Delivery, Dipendra Raj Gyawali

Bioengineering Theses - Archive

In situ crosslinkable elastic materials are increasingly being explored for various biomedical applications such as drug delivery and tissue engineering due to their site specific nature. The creation of an in situ crosslinkable elastomer rich in pendant chemistry has been a challenge in the field of biomaterials. Herein, we have developed two new in situ biodegradable materials: poly(octamethylene maleate citrates) (POMC) and poly(poly(ethylene glycol) maleate citrate) (PPEGMC). These materials are all low molecular weight in their pre-polymeric form, which shows their potential to be used as an injectable biomaterial. The preservation of pendant carboxylic and hydroxyl groups in these polymeric …

Development Of An Optical Spectroscopic Method To Detect Neurohemodynamic Changes Induced By Pain In Rats, Sweta Narvenkar

Bioengineering Theses - Archive

In my optical spectroscopy study, multi-channel, thin optical probes with short source-detector separation have been implemented, calibrated, and used along with a multi-channel spectrometer as a quantitative technique to observe changes in vascular hemoglobin concentration and hemoglobin oxygen saturation as well as light scattering of tissues. Each of the four needle probes used in my study consists of two bifurcated fibers; one fiber is connected to a halogen light source and the other fiber to a CCD-array spectrometer having a spectral window from 450 nm to 900 nm. Each fiber is 100 micron in diameter. As we utilized the four …

Gold Nanorods As Contrast Agents For Biological Imaging: Optical Properties, Surface Conjugation And Photothermal Effects, Ling Tong, Qingshan Wei, Alexander Wei, Ji-Xin Cheng

Other Nanotechnology Publications

Gold nanorods (NRs) have plasmon-resonant absorption and scattering in the near-infrared (NIR) region, making them attractive probes for in vitro and in vivo imaging. In the cellular environment, NRs can provide scattering contrast for darkfield microscopy, or emit a strong two-photon luminescence due to plasmon-enhanced two-photon absorption. NRs have also been employed in biomedical imaging modalities such as optical coherence tomography or photoacoustic tomography. Careful control over surface chemistry enhances the capacity of NRs as biological imaging agents by enabling cell-specific targeting, and by increasing their dispersion stability and circulation lifetimes. NRs can also efficiently convert optical energy into heat, …

Magnitude And Variability In Emissions Savings In The Corn-Ethanol Life Cycle From Feeding Co-Products To Livestock, Virgil R. Bremer, Adam Liska, Terry J. Klopfenstein, Galen E. Erickson, Haishun Yang, Daniel T. Walters, Kenneth G. Cassman

Adam Liska Papers

Conclusions

• Co-product GHG emissions credit varied by >2-fold, from 11.5 to 28.3 gCO₂e per MJ of ethanol produced

• Co-product GHG emissions credit depend on
-types of co-products produced
-proportion fed to beef cattle vs. diary or swine
-location of corn production; the CP credit is highest in regions where GHG kg^-1grain are highest

• Depending on CP production types and feeding livestock classes, corn-ethanol net life cycle GHG intensity is 44-56 gCO₂e per MJ

• Midwest corn-ethanol reduces GHG emissions compared to gasoline by 47% on average, with co-products offsetting 23% of …

Differential Regulation Of Vitamin D Receptor (Vdr) By P53, P63 And P73, Ramakrishna Kommagani

Browse all Theses and Dissertations

The tumor suppressor p53 is the single most altered gene in human cancers. p53 homologues, p63 and p73 play a major role in development and in human cancer. Both p63and p73-null mice exhibit profound developmental abnormalities, suggesting a vital role for p63 and p73 in development. Although the role of p73 in human cancers is well established, the role of p63 still remains to be understood. While p63 plays a major role in development, p73 plays a major role in tumor suppression as well as in development. Although a functional co-operation is evident between each member of p53 family, additional …

Antibacterial Properties Of A Tri-Sodium Citrate Modified Glass Polyalkenoate Cement, A. W. Wren, D. Boyd, R. Thornton, J. C. Cooney, Mark R. Towler

Chemical and Biochemical Engineering Faculty Research & Creative Works

Primary deep infection following joint replacement surgery accounts for 7% of all revisions. Glass polyalkenoate cements (GPCs) have previously been shown to exhibit antibacterial properties. The present study had two objectives. The first was to determine if addition of tri-sodium citrate (TSC) to the powder phase of an Al-free GPC (0.04 SrO-0.12 CaO-0.36 ZnO-0.48 SiO2, by mole fraction) enhanced the resultant cement's antibacterial properties against three strains of bacteria that are commonly found in periprosthetic sites following total joint replacements (TJRs); namely, E. coli, B. fragilis, and S. epidermidis. Four cement sets were prepared, which contained 0 wt% TSC (control), …

A New Pulsed Electric Field Therapy For Melanoma Disrupts The Tumor's Blood Supply And Causes Complete Remission Without Recurrence, Richard Nuccitelli, Xinhua Chen, Andrei G. Pakhomov, Wallace H. Baldwin, Saleh Sheikh, Jennifer L. Pomicter, Wei Ren, Chris Osgood, R. James Swanson, Juergen F. Kolb, Stephen J. Beebe, Karl H. Schoenbach

Bioelectrics Publications

We have discovered a new, ultrafast therapy for treating skin cancer that is extremely effective with a total electric field exposure time of only 180 mu sec. The application of 300 high-voltage (40 kV/cm), ultrashort (300 nsec) electrical pulses to murine melanomas in vivo triggers both necrosis and apoptosis, resulting in complete tumor remission within an average of 47 days in the 17 animals treated. None of these melanomas recurred during a 4-month period after the initial melanoma had disappeared. These pulses generate small, long-lasting, rectifying nanopores in the plasma membrane of exposed cells, resulting in increased membrane permeability to …

Therapeutic Ultrasound Angioplasty: The Risk Of Arterial Perforation. An In Vitro Study, Mark Wylie, Garrett Mcguinness, Graham Gavin

Conference Papers

The use of therapeutic ultrasound delivered via small diameter wire waveguides may represent an emerging minimally invasive approach in the treatment of chronic total occlusions (CTOs), calcified and fibrous plaques. The distal-tip mechanical vibrations (typically 0-210 μm peak-to-peak) have been reported to debulk rigid calcified and fibrous tissues while healthy elastic arterial tissue remains largely unaffected. The risk of arterial (healthy tissue) perforation with energized waveguides is not fully understood. An ultrasonic apparatus capable of delivering a range of wire waveguide distal-tip displacements, up to 80 μm peak-to-peak (p-p), at an operational frequency of 22.5 KHz (+/- 6%) has been …

A Mobile Ecg Monitoring System With Context Collection, Jin Peng Li, Damon Berry, Richard Hayes

Conference Papers

Preventative health management represents a shift from the traditional approach of reactive treatment-based healthcare towards a proactive wellness-management approach where patients are encouraged to stay healthy with expert support when they need it, at any location and any time. This work represents a step along the road towards proactive, preventative healthcare for cardiac patients. It seeks to develop a smart mobile ECG monitoring system that requests and records context information about what is happening around the subject when an arrhythmia event occurs. Context information about the subject’s activities of daily living will, it is hoped, provide an enriched data set …

Development Of Novel Microwave Cooking Model For Not-Ready-To Eat Foods, Sohan Birla, Krishnamoorthy Pitchai, Jeyamkondan Subbiah, David D. Jones

Department of Agricultural and Biological Systems Engineering: Presentations and White Papers

Recently safety of microwave cooked food has come under scrutiny because of recent outbreak and recalls associated with some of these not-ready-to-eat (NRTE) frozen foods. Heating uniformity of these foods is paramount in rendering the foods safe for consumption. Degree of uneven microwave heating is influenced by both microwave oven and characteristics of food load which decides the electric field distribution within the food load. Given the complexity of parameters, a computer model is always desirable to optimize heating uniformity by proper selection of food shape, proportions, plating, packaging selection and more. Earlier many researchers have made one or more …

Process Simulation Of Dilute Acid Pretreatment Of Coastal Bermudagrass For Bioethanol Production, Arthur Redding, Deepak R. Keshwani, Jay J. Cheng

Department of Agricultural and Biological Systems Engineering: Presentations and White Papers

Coastal bermudagrass is a promising lignocellulosic feedstock for bioethanol production. It is well suited for the Southeastern United States where it is currently grown for hay production and nutrient management in animal farming operations. Prior experiments have generated sugar and sugar degradation data from the dilute acid pretreatment and enzymatic hydrolysis of bermudagrass over a range of pretreatment conditions. Experimentally, the yield of total glucose and xylose was maximized at 93 % of the theoretical value for the pretreatment conditions 140 °C and 1.2 % sulfuric acid (w/w) for a residence time of 30 minutes. To explore further potential optimum …

Continuous Glucose Monitoring Microsensor With A Nanoscale Conducting Matrix And Redox Mediator, Daniel Pesantez

Legacy Theses & Dissertations (2009 - 2024)

The major limiting factor in kidney clinical transplantation is the shortage of transplantable organs. The current inability to distinguish viability from non-viability on a prospective basis represents a major obstacle in any attempt to expand organ donor criteria. Consequently, a way to measure and monitor a relevant analyte to assess kidney viability is needed. For the first time, the initial development and characterization of a metabolic microsensor to assess kidney viability is presented. The rate of glucose consumption appears to serve as an indicator of kidney metabolism that may distinguish reversible from irreversible kidney damage. The proposed MetaSense (Metabolic Sensor) …

Three-Dimensional Hydrogel Cell Culture Systems For Modeling Neural Tissue, John P. Frampton

Legacy Theses & Dissertations (2009 - 2024)

Two-dimensional (2-D) neural cell culture systems have served as physiological models for understanding the cellular and molecular events that underlie responses to physical and chemical stimuli, control sensory and motor function, and lead to the development of neurological diseases. However, the development of three-dimensional (3-D) cell culture systems will be essential for the advancement of experimental research in a variety of fields including tissue engineering, chemical transport and delivery, cell growth, and cell-cell communication. In 3-D cell culture, cells are provided with an environment similar to tissue, in which they are surrounded on all sides by other cells, structural molecules …

Biotechnology For Immune Cell Detection And Evaluation : Devices Specifically Designed To Capture, Detect Or To Evaluate Alterations In Leukocyte Structure And Function, Thomas Joseph Zieziulewicz

Legacy Theses & Dissertations (2009 - 2024)

The advent of Nano-biotechnology has opened a whole new area of biological study that has allowed us to pattern, manipulate, separate, evaluate and detect biological structures and functions that were previously not possible. This dissertation will describe different types of micro-fabricated devices that were designed to quantify and/or evaluate the functional activities of cells of the immune system. The micro-fabricated devices were developed in collaboration with our colleagues at Princeton University as part of our Cellular Micro-dynamics Program of the Nanobiotechnology Center (NBTC) at Cornell University.

Regulation Of Intracellular Calcium Concentration By Nanosecond Pulsed Electric Fields, Shaka S. Scarlett, Jody A. White, Peter F. Blackmore, Karl H. Schoenbach, Juergen Kolb

Bioelectrics Publications

Changes in [Ca²⁺]_i response of individual Jurkat cells to nanosecond pulsed electric fields (nsPEFs) of 60 ns and field strengths of 25, 50, and 100 kV/cm were investigated. The magnitude of the nsPEF-induced rise in [Ca²⁺]_i was dependent on the electric field strength. With 25 and 50 kV/cm, the [Ca²⁺]_i response was due to the release of Ca²⁺ from intracellular stores and occurred in less than 18 ms. With 100 kV/cm, the increase in [Ca²⁺]_i was due to both internal release and to influx across the plasma …

Nanoscale Approaches For Biomolecule Separation And Detection, Swati Goyal

Bioengineering Theses - Archive

Nanotechnology has the potential to contact and impact the biological interactions at the most basic chemical and physical levels. New approaches to nanodevices allow high sensitivity and specificity with low sample requirement. Such devices are potential candidates for early disease detection at molecular levels and have important implications in associated therapeutics.This research work focuses on two different areas: developing devices for DNA detection, protein enrichment and exploring material properties to fabricate microscale/nanoscale structures. In one approach, hairpin probe DNA was used to detect fmol of ss-DNA from k-ras oncogene. In another approach, nanochannel based device was developed to selectively increase …

Numerical Modeling Of Hemodynamics In The Thoracic Aorta And Alterations By Dacron Patch Treatment Of Aortic Coarctation, Ronak Jashwant Dholakia

Master's Theses (2009 -)

Coarctation of the aorta (CoA) is a major congenital heart disease, characterized by a severe stenosis of the proximal descending thoracic aorta. Traditionally, surgery has been the treatment of choice for CoA. Dacron patch aortoplasty gained increased popularity after its introduction in the mid-twentieth century due to its advantages over other surgical treatment methods available at the time. A major complication with Dacron patch aortoplasty has been the formation of late aneurysm with as much as 51% incidence reported in follow up studies. The change in aortic morphology and formation of aneurysms after Dacron patch surgery could lead to local …

Nano-Mechanics Of Cartilage Glycosaminoglycans Using Molecular Dynamics Methods, Kevin Neil Hendrickson

Master's Theses

Articular Cartilage (AC) is the main load carrying material in synovial joints {Hamerman, 1962} and degeneration of AC can cause pain in the form of arthritis. Current work is centered on the method of replacing damaged cartilage inside the body (in vivo) with tissue engineered outside the body (ex vivo) {Temenoff, 2000}. In order to engineer tissue ex vivo similar to the native tissue in structure and function there must be a comprehensive understanding of the mechanical properties of AC. This work focuses on the study of glycosaminoglycans (GAGs), a molecule known to be primarily responsible for the compressive stiffness …

A Study On The Effect Of Mechanical Stretch And Aligned Scaffold Architecture On Morphology Of Rat Ventricular Cells, Shruti Kanakia

Bioengineering Theses - Archive

Heart disease is one of the major causes of death in developing and industrialized countries. Myocardial infarction leads to remodeling of the left ventricle, which severely affects the pumping efficiency of the heart. In order to provide mechanical support to left ventricle the scaffold material should be elastic and mechanically strong. For the success of cardiac graft in vivo one of the important factor is ability of cardiac myocyte morphology to resemble that in vivo. The goal of this study is to build thick, prevascularized cardiac graft for myocardial infarction repair. Mechanical stress has been recognized as one of the …

An Evaluation Of The Biomechanical Properties Of The Superficial Musculoaponeurotic System, Matthew David Ruff

Bioengineering Theses - Archive

The Superficial Musculoaponeurotic System (SMAS) is a well defined tissue layer of the face commonly utilized in facial surgery, including facelifts. There are several reasons for the utilization of this tissue, including aesthetic results and reliability. Basic to the outcomes for these procedures are the inherent biomechanical properties of the SMAS. Most important for the surgeon in this regard are tissue burst pressure, elasticity, stress-relaxation under load, and creep. This study experimentally determines the biomechanical properties for human cadaveric tissue specimens. As well as defining the cited biomechanical properties, the study examines how they change, as sampled from different regions …