Biomedical Commons^™

A Knowledge-Based Clinical Toxicology Consultant For Diagnosing Multiple Exposures, Joel D. Schipper, Douglas D. Dankel Ii, A. Antonio Arroyo, Jay L. Schauben

Publications

Objective: This paper presents continued research toward the development of a knowledge-based system for the diagnosis of human toxic exposures. In particular, this research focuses on the challenging task of diagnosing exposures to multiple toxins. Although only 10% of toxic exposures in the United States involve multiple toxins, multiple exposures account for more than half of all toxin-related fatalities. Using simple medical mathematics, we seek to produce a practical decision support system capable of supplying useful information to aid in the diagnosis of complex cases involving multiple unknown substances.

Methods: The system is automatically trained using data mining …

Design And Fabrication Of Nanofluidic Systems With Integrated Sensing Electrodes For Rapid Biomolecule Characterization, Taylor Bradley Busch

Graduate Theses and Dissertations

A transparent nanofluidic system with embedded sensing electrodes was designed and fabricated by integrating Atomic Force Microscopy (AFM) nanolithography, Focused Ion Beam (FIB) milling and metal deposition, and standard microfabrication processing. The fabrication process started with the evaporation of chrome/gold (Cr/Au) onto a Pyrex 7740 wafer followed by photolithography and wet etching of the microchannels. The wafer was patterned a second time to form Au microelectrodes with 15-45 micrometer separation gaps in the nanochannel region. Sensing electrodes (up to one micron wide) were then deposited using FIB to bridge the gaps. The nanochannels were realized through both AFM nanolithography and …

The Geometry And Sensitivity Of Ion-Beam Sculpted Nanopores For Single Molecule Dna Analysis, Ryan Connor Rollings

Graduate Theses and Dissertations

In this dissertation, the relationship between the geometry of ion-beam sculpted solid-state nanopores and their ability to analyze single DNA molecules using resistive pulse sensing is investigated. To accomplish this, the three dimensional shape of the nanopore is determined using energy filtered and tomographic transmission electron microscopy. It is shown that this information enables the prediction of the ionic current passing through a voltage biased nanopore and improves the prediction of the magnitude of current drop signals when the nanopore interacts with single DNA molecules. The dimensional stability of nanopores in solution is monitored using this information and is improved …

Design And Testing Of Novel Mouthguard With Intermediate Nitinol And Foam Layers, Adam Kessler

UNLV Theses, Dissertations, Professional Papers, and Capstones

It is the aim of this study to investigate a novel mouthguard design that incorporates the use of a nickel-titanium (Nitinol) layer and thin foam layer in addition to EVA layers. It is thought that the Nitinol layer can distribute the force of an impact and that the thin foam layer may absorb this distributed force better than a solid EVA mouthguard of the same thickness. Rectangular, flat coupons representative of several mouthguard configurations were constructed for testing using an instrumented drop-weight impact tower. The coupon configurations include a control made of laminated EVA, a group of laminated EVA and …

Closed Loop Control Of A Cylindrical Tube Type Ionic Polymer Metal Composite (Ipmc), Benjamin Mead

UNLV Theses, Dissertations, Professional Papers, and Capstones

The goal of this research is to provide a framework for the integration of tube type, cylindrical Ionic Polymer Metal-Composite (IPMC) into conventional devices. IPMCs are one of the most widely used types of electro-active polymer actuator, due to their low electric driving potential and large deformation range. For this research a tube type IPMC was investigated. This IPMC has a circular cross section with four separate electrodes on its surface and a hole through the middle. The four electrodes allow for biaxial bending and accurate control of the tip location. One of the main advantages of using this type …

Enhanced Diagnostic Accuracy Of Mammograms On A Mobile Device, Sharanya Padmanabhan

Open Access Theses

With the death of a woman every 13 minutes in the US, and one every minute worldwide, due to breast cancer, the need for early detection cannot be overstated. Mammography is a boon for both early detection and screening of breast tumors. It is an imaging system that uses low dose (9mrem) x-rays for examining the breasts, by the electrons reflected from the tissues (thermoelectric effect). However, there are 20% false positives and 10% false negatives in current practice. Hence, there is a critical need for enhancing the accuracy of these mammograms. Towards this, this thesis was aimed at enhancing …

Modeling Tools For Conformal Orthotic Devices, Steven David Riddle

Open Access Theses

The purpose of this thesis is to advance the design of conformal orthotic devices through the development of two modeling tools to address knowledge gaps in the field.

The field of human orthotics has been continually troubled by identifying successful methods of harnessing devices to the body. Past orthotics have utilized a rigid framework with minimal degrees of freedom (DOFs) driven by hard actuators attached to the body at select anchor points. Many devices design the structure and anchor points such that they reduce the degrees of freedom of a targeted joint, limiting the user's mobility and often causing the …

Using Multi-Processors To Reconstruct Images With Proton Computed Tomography, Chenwei Xu

Theses Digitization Project

This project will employ the use of multi-processor technology to reconstruct image data as fast as possible. Two-dimensional image reconstruction technique reconstructs images by solving a linear equation: A x x =b, where A is the path matrix of proton histories, b is electron matrix of the image, and x is the matrix of image. One row in matrix A represents one beam. Matrix A consists of a number of beam projections to the image, and each projection consists of a number of beams. Contains source code.

Detection Of Brain Abnormalities In Football Players Through Diffusion Weighted Imaging, Allan Emilio Diaz Gaez

Open Access Theses

Depression and cognitive impairment are commonly found in retired football players. Although they receive high magnitude hits to the head, the majority of the hits are sub-concussive, resulting in no clinical symptoms. Recent work using functional magnetic resonance (fMRI) and neurocognitive testing confirms that blows, causing changes in brain function, might not necessarily result in clinical diagnosis of concussion. Furthermore, cognitive deficiency in football players may be attributed to repetitive sub-concussive blows to the head. Diffusion weighted imaging (DWI) has previously been utilized to detect white matter (WM) abnormalities in mild traumatic brain injury (mTBI) patients, including those who have …

Sediment And Nutrient Behaviour On The River Bandon, Ireland, S. T. Harrington, Joseph R. Harrington

Conference Papers

This paper presents aspects of sediment and nutrient behaviour on the River Bandon which is located in the South Western River Basin District in Ireland; it is a relatively large sized river catchment in an Irish context with a catchment area of 608 km2. The river catchment is primarily agricultural with some pockets of urban development. The river is prone to flooding on stretches, features a number of special areas of conservation and is distinguished by both suspended and bed load transport. Continuous monitoring of turbidity commenced in February 2010. Manual sampling and testing for suspended sediment concentration and a …

Study Of The Effects Of Changing Physiological Conditions On Dielectric Properties Of Breast Tissues, Abas Sabouni, Camerin Hahn, Sima Noghanian, Edward Sauter, Tim Weiland

Electrical Engineering Faculty Publications

This paper addresses the changes in the physical characteristics (temperature and water/blood content) of breast tissue under different physiological conditions. We examined ex vivo specimens of breast tissue excised at the time of surgery to study the effects of physiological conditions on dielectric properties. We observed that the dielectric properties strongly depend on tissue physiological state. When the biological tissues undergo physiological changes, such as those due to disease or those induced by external changes such as variations in the environmental temperature, the microscopic processes deviate from their normal state and impact the overall dielectric properties. This suggests that microwave …

Recruitment Of The Intracellular Ca2+ By Ultrashort Electric Stimuli: The Impact Of Pulse Duration, Iurii Semenov, Shu Xiao, Olga N. Pakhomova, Andrei G. Pakhomov

Bioelectrics Publications

Nanosecond-duration electric stimuli are distinguished by the ability to permeabilize intracellular membranes and recruit Ca²⁺ from intracellular stores. We quantified this effect in non-excitable cells (CHO) using ratiometric Ca²⁺ imaging with Fura-2. In a Ca²⁺-free medium, 10-, 60-, and 300-ns stimuli evoked Ca2⁺ transients by mobilization of Ca²⁺ from the endoplasmic reticulum. With 2 mM external Ca²⁺, the transients included both extra- and intracellular components. The recruitment of intracellular Ca²⁺ increased as the stimulus duration decreased. At the threshold of 200–300 nM, the transients were amplified by calcium-induced calcium release. We …

Inkjet Based Personalized Screening Platform For Cancer Therapy, Jorge Ivan Rodriguez

Open Access Theses & Dissertations

The new paradigm of personalized medicine is beginning to affect clinical practice. In particular, many of the advances in genomics and proteomics have made personalized screening and therapeutic inventions possible. On chip, cellomics approaches to screening and intervention are becoming more commonplace. Cancer therapies may benefit from the rise in `-omics' technologies. In addition, the availability of rapid screening data is crucial to mitigate cancer propagation and increase the possibility of patient recovery. This study is an endeavor to develop a cellomic anticancer drug screening process based on inkjet printing. Previous research has demonstrated that inkjet based screening can reliably …

Effects Of Blood Flow On The Heating Of Cardiac Stents Due To Radio Frequency Fields, Nate Ian Elder

Open Access Theses

A safety concern during MRI scans with implanted medical devices is heating induced by the incident RF field. This research was performed to better understand the heating of cardiac stents during MRI. Heating of cardiac stents tends to occur at their ends. The temperature rise will be affected by blood flow through the lumen of the stent. In this work, an experiment was performed to simulate heating of a cardiac stent in the presence of blood flow during exposure to the electric field induced by a 64 MHz magnetic field, which corresponds to MRI at 1.5 T. The test procedure …

Vibrational Photoacoustic Tomography: Deep Tissue Imaging With Biomarker Sensitivity, Rui Li

Open Access Theses

As a molecular and functional imaging modality, photoacoustic imaging has been applied to animals or human organs such as breast, brain and skin. Till now, the contrast mechanism of photoacoustic imaging is mainly based on electronic absorption in visible and near infrared region. Inherent molecular vibration offers a contrast mechanism for chemical imaging in a label free manner. In vibrational microscopy based on either infrared absorption or Raman scattering, the imaging depth is limited to the ballistic photon mean free path, which is a few hundred microns in a biological sample. Owing to much weaker acoustic scattering in tissues as …

The Perceptual Salience Of Amplitude Modulated Cortical Stimulation: Peak Equivalence Or Rms Equivalence?, Oliver Brian Regele

Open Access Theses

Intracortical microstimulation (ICMS) is a method of electrically stimulating the primary motor, visual, somatosensory and auditory cortices in the brain. The goal is to replace deficient sensory function in cases such as deafness, blindness and paralysis. However these neural prosthetics have not made the full transition to clinical trials due to a lack of sufficient investigation into the optimal stimulation waveforms. Sinusoidally amplitude modulated (SAM) signals have been shown to be important to sensory systems, yet have not been fully explored as a stimulation waveform for stimulating cortical tissue.

This work represents an investigation into the detection characteristics of electrical …

Modulation Of Cell-Matrix Interaction For Cryopreservation Of Engineered Tissue, Angela Christine Seawright

Open Access Theses

Long term preservation of functional engineered tissues can significantly advance tissue engineering industry and regenerative medicine. Several preservation techniques have been proposed and investigated for this purpose, and cryopreservation is a leading candidate. While tissues are cryopreserved, ice forms in both the extracellular and intracellular spaces and causes freezing-induced spatiotemporal deformation of the tissue. During this process the cells undergo dehydration by the freezing-induced osmotic pressure difference and mechanical deformation, transmitted through cell-extracellular matrix adhesions. However, the significance and interaction of these cellular level transport and mechanics processes are not well understood. Therefore, this study aims to establish mechanistic understanding …

Role Of Microrna-155 In A Mouse Model Of Colon Cancer., Claire Mitchell Midyette

Theses and Dissertations

Colorectal cancer remains the third most common malignancy and the fourth most common cause of cancer mortality worldwide. Dysregulated miRNA levels are associated with several types of malignancies and may serve as important biomarkers and/or therapeutic targets in colorectal cancer. We examined the role of miRNA-155 on tumorigenesis and associated symptoms using a well-characterized mouse model of colorectal cancer. C57BL/6 wild-type mice and miRNA-155-/- mice (n=7-13 group) were given a single injection of AOM (10mg/Kg) followed by 3 cycles of DSS (2% in the water for 1 week followed by 2 weeks of plain water). A C57BL/6 wild-type group that …

Assessment And Evaluation Of The Dynamic Behavior Of Muscles With Special Reference To Subjects With Diabetes Mellitus, Jorge Garza-Ulloa

Open Access Theses & Dissertations

Diabetes mellitus (simply diabetes) is a group of metabolic diseases in which a person has high blood sugar, either because the body does not produce enough insulin, or because cells do not respond to the insulin that is produced. Each year, the costs of diabetes rise. Diabetes and its complications cost our national economy. Two new methods are proposed to measure the diabetes implications in the muscles of lower body: Muscle energy expenditure analysis based on the detection of muscle transition-to-fatigue, and Natural Fuzzy logic method for differential analysis in muscle/joint. Then the results are compared with the traditional method …

Investigation Of Start Domain Proteins In Human Luteinized Cells And Cos-1 Cells, Bo Shi

Theses and Dissertations

After the luteinizing hormone surge of the menstrual cycle, the ovarian follicular granulosa and theca cells terminally differentiate to form the luteal cells of the corpus luteum. During this process known as luteinization, granulosa cells begin to synthesize large quantities of progesterone, a hormone essential for pregnancy. The rate limiting step for the de novo synthesis of pregnenolone (the precursor to progesterone) is the transport of cholesterol from the outer to the inner mitochondrial membrane, a process mediated by STARD1. STARD1 contains a C-terminal lipid binding domain holding one molecule of cholesterol, and an N-terminal domain targeting STARD1 to the …