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Analog Implementation Of The Hodgkin-Huxley Model Neuron, Zachary D. Mobille, George H. Rutherford, Jordan Brandt-Trainer, Rosangela Follmann, Epaminondas Rosa 2019 Illinois State University

Analog Implementation Of The Hodgkin-Huxley Model Neuron, Zachary D. Mobille, George H. Rutherford, Jordan Brandt-Trainer, Rosangela Follmann, Epaminondas Rosa

Annual Symposium on Biomathematics and Ecology: Education and Research

No abstract provided.


Period Drift In A Neutrally Stable Stochastic Oscillator, Kevin Sanft 2019 Illinois State University

Period Drift In A Neutrally Stable Stochastic Oscillator, Kevin Sanft

Annual Symposium on Biomathematics and Ecology: Education and Research

No abstract provided.


Treating Epilepsy With Physics, Louis R. Nemzer 2019 Nova Southeastern University

Treating Epilepsy With Physics, Louis R. Nemzer

Louis R Nemzer

No abstract provided.


Modeling Proton Relative Biological Effectiveness Using Monte Carlo Simulations Of Microdosimetry, Mark A. Newpower 2019 The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences

Modeling Proton Relative Biological Effectiveness Using Monte Carlo Simulations Of Microdosimetry, Mark A. Newpower

UT GSBS Dissertations and Theses (Open Access)

Proton therapy is a radiotherapy modality that can offer a better physical dose distribution when compared to photon radiotherapy by taking advantage of the Bragg peak, a narrow region of rapid energy loss. Proton therapy is also known to offer an enhanced relative biological effectiveness (RBE) compared to photons. In the current clinical standard, RBE is fixed at 1.1 at all points along the proton beam, meaning protons are assumed to require 10% less dose than photons to achieve target coverage and organ at risk (OAR) sparing. However, there is mounting clinical evidence, and a significant number of in ...


Commissioning Of Micro-Cube Thermoluminescent Dosimeters For Small Field Dosimetry Quality Assurance In Radiotherapy, Brandon Luckett 2019 The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences

Commissioning Of Micro-Cube Thermoluminescent Dosimeters For Small Field Dosimetry Quality Assurance In Radiotherapy, Brandon Luckett

UT GSBS Dissertations and Theses (Open Access)

Small field dosimetry presents complications and uncertainties that could be circumvented by using detectors which are smaller than the radiation field. This study evaluates the reproducibility and accuracy of TLD micro-cubes for use in stereotactic radiosurgery (SRS) remote auditing quality assurance (QA) for treatment centers participating in clinical trials. This study tested the hypothesis that TLD micro-cubes could be commissioned to evaluate small field dosimetry, and provide reproducibility within 3%, as well as assure agreement between measured dose and calculated doses to within 5%.

The aims of this thesis were to characterize and commission TLD micro-cubes as well as to ...


Quantifying Uncertainty In A Measurement-Based Assessment Of Relative Biological Effectiveness In Carbon Ion Radiotherapy, Shannon Hartzell 2019 The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences

Quantifying Uncertainty In A Measurement-Based Assessment Of Relative Biological Effectiveness In Carbon Ion Radiotherapy, Shannon Hartzell

UT GSBS Dissertations and Theses (Open Access)

One of the largest inconsistencies in dose delivered during carbon ion therapy is due to uncertainties in relative biological effectiveness (RBE), a value that is calculated via one of several clinically implemented algorithms. This study investigates the uncertainty in measured microdosimetric parameters for RBE calculation by the Microdosimetric Kinetic Model (MKM), Repair Misrepair Fixation model (RMF), and Local Effect Model I (LEM) using a Tissue Equivalent Proportional Counter (TEPC).

Microdosimetric spectra, kinetic energy spectra, and dose fragment contributions were calculated using Monte Carlo (GEANT IV) for monoenergetic and SOBP carbon beams of clinical energy. From microdosimetric spectra, lineal energy values ...


Impact Of Excitation-Inhibition Balance/Imbalance On Dynamics Of Cortical Neural Networks, Vidit Agrawal 2019 University of Arkansas, Fayetteville

Impact Of Excitation-Inhibition Balance/Imbalance On Dynamics Of Cortical Neural Networks, Vidit Agrawal

Theses and Dissertations

The purpose of this research is to study the implications of Excitation/Inhibition balance and imbalance on the dynamics of ongoing (spontaneous) neural activity in the cerebral cortex region of the brain.

The first research work addresses the question that why among the continuum of Excitation-Inhibition balance configurations, particular configuration should be favored? We calculate the entropy of neural network dynamics by studying an analytically tractable network of binary neurons. Our main result from this work is that the entropy maximizes at regime which is neither excitation-dominant nor inhibition-dominant but at the boundary of both. Along this boundary we see ...


Quantifying Complex Systems Via Computational Fly Swarms, Troy Taylor 2019 Linfield College

Quantifying Complex Systems Via Computational Fly Swarms, Troy Taylor

Senior Theses

Complexity is prevalent both in natural and in human-made systems, yet is not well understood quantitatively. Qualitatively, complexity describes a phenomena in which a system composed of individual pieces, each having simple interactions with one another, results in interesting bulk properties that would otherwise not exist. One example of a complex biological system is the bird flock, in particular, a starling murmuration. Starlings are known to move in the direction of their neighbors and avoid collisions with fellow starlings, but as a result of these simple movement choices, the flock as a whole tends to exhibit fluid-like movements and form ...


Characteristics Of Sulfur Atoms Adsorbed On Ag(100), Ag(110), And Ag(111) As Probed With Scanning Tunneling Microscopy: Experiment And Theory, Peter M. Spurgeon, Da-Jiang Liu, Holly Walen, Junepyo Oh, Hyun Jin Yang, Yousoo Kim, Patricia A. Thiel 2019 Iowa State University

Characteristics Of Sulfur Atoms Adsorbed On Ag(100), Ag(110), And Ag(111) As Probed With Scanning Tunneling Microscopy: Experiment And Theory, Peter M. Spurgeon, Da-Jiang Liu, Holly Walen, Junepyo Oh, Hyun Jin Yang, Yousoo Kim, Patricia A. Thiel

Chemistry Publications

In this paper, we report that S atoms on Ag(100) and Ag(110) exhibit a distinctive range of appearances in scanning tunneling microscopy (STM) images, depending on the sample bias voltage, VS. Progressing from negative to positive VS, the atomic shape can be described as a round protrusion surrounded by a dark halo (sombrero) in which the central protrusion shrinks, leaving only a round depression. This progression resembles that reported previously for S atoms on Cu(100). We test whether DFT can reproduce these shapes and the transition between them, using a modified version of the Lang–Tersoff–Hamann ...


Magnetic Borophenes From An Evolutionary Search, Meng-Hong Zhu, Xiao-Ji Weng, Guoying Gao, Shuai Dong, Ling-Fang Lin, Wei-Hua Wang, Qiang Zhu, Artem R. Oganov, Xiao Dong, Yongjun Tian, Xiang-Feng Zhou, Hui-Tian Wang 2019 Nankai University

Magnetic Borophenes From An Evolutionary Search, Meng-Hong Zhu, Xiao-Ji Weng, Guoying Gao, Shuai Dong, Ling-Fang Lin, Wei-Hua Wang, Qiang Zhu, Artem R. Oganov, Xiao Dong, Yongjun Tian, Xiang-Feng Zhou, Hui-Tian Wang

Physics & Astronomy Faculty Publications

A computational methodology based on ab initio evolutionary algorithms and spin-polarized density functional theory was developed to predict two-dimensional magnetic materials. Its application to a model system borophene reveals an unexpected rich magnetism and polymorphism. A metastable borophene with nonzero thickness is an antiferromagnetic semiconductor from first-principles calculations, and can be further tuned into a half-metal by finite electron doping. In this borophene, the buckling and coupling among three atomic layers are not only responsible for magnetism, but also result in an out-of-plane negative Poisson's ratio under uniaxial tension, making it the first elemental material possessing auxetic and magnetic ...


Seeing Eye To Eye: A Machine Learning Approach To Automated Saccade Analysis, Maigh Attre 2019 University of Connecticut

Seeing Eye To Eye: A Machine Learning Approach To Automated Saccade Analysis, Maigh Attre

Honors Scholar Theses

Abnormal ocular motility is a common manifestation of many underlying pathologies particularly those that are neurological. Dynamics of saccades, when the eye rapidly changes its point of fixation, have been characterized for many neurological disorders including concussions, traumatic brain injuries (TBI), and Parkinson’s disease. However, widespread saccade analysis for diagnostic and research purposes requires the recognition of certain eye movement parameters. Key information such as velocity and duration must be determined from data based on a wide set of patients’ characteristics that may range in eye shapes and iris, hair and skin pigmentation [36]. Previous work on saccade analysis ...


Optical Enhancement In Periodic Plasmonic Gratings For Sers And Metal-Semiconductor-Metal Photodetectors (Msm-Pds) Applications, Ahmad Aziz Darweesh 2019 University of Arkansas, Fayetteville

Optical Enhancement In Periodic Plasmonic Gratings For Sers And Metal-Semiconductor-Metal Photodetectors (Msm-Pds) Applications, Ahmad Aziz Darweesh

Theses and Dissertations

This dissertation is aimed to numerically study the effect of plasmonic grating electrodes on the efficiency of metal-semiconductor-metal photodetectors (MSM PDs) and the sensitivity of Surface Enhanced Raman Spectroscopy (SERS). This research can benefit many areas of nanoscience and optics, including plasmonic applications, such as, super lenses, nano-scale optical circuits, optical filters, surface plasmon enhanced photo-detectors solar cells, imaging sensors, charge-coupled devices (CCD), and optical-fiber communication systems. Several parameters, wire widths and thickness, gap space, taper angle, and the incident wavelength and angle, were investigated. The goal of this research is to utilize the plasmonic phenomenon by using plasmonic gratings ...


Quantification Of Contrast-Enhanced Ultrasound, Joseph Pathoulas 2019 College of Saint Benedict/Saint John's University

Quantification Of Contrast-Enhanced Ultrasound, Joseph Pathoulas

All College Thesis Program, 2016-present

The aim of this experiment was to investigate the effect of manipulating ultrasound scanner settings on time-intensity curve parameters in a tube perfusion phantom system using contrast-enhanced ultrasound imaging. Imaging was performed using a Philips LOGIQ E9 ultrasound scanner equipped with a C1-6VN transducer and utilized two different microbubble contrast agents: Definity and Lumason. The ultrasound scanner settings manipulated included: gain, dynamic range, and frequency. Additionally, relative microbubble concentration, microbubble type, and perfusion flow rate were manipulated. Four time-intensity curve parameters (time to peak, area under curve, gradient, peak intensity) were measured from linearized pixel data. Time to peak was ...


Mg Assisted Flux Growth And Characterization Of Single Crystalline Sm2co17, Tej Nath Lamichhane, Qisheng Lin, Valentin Taufour, Andriy Palasyuk, Tribhuwan Pandey, David Parker, Sergey L. Bud’ko, Paul C. Canfield 2019 Iowa State University and Ames Laboratory

Mg Assisted Flux Growth And Characterization Of Single Crystalline Sm2co17, Tej Nath Lamichhane, Qisheng Lin, Valentin Taufour, Andriy Palasyuk, Tribhuwan Pandey, David Parker, Sergey L. Bud’Ko, Paul C. Canfield

Ames Laboratory Accepted Manuscripts

This paper presents details of Mg-assisted flux growth of Sm2Co17 single crystals in a Ta crucible well below the melting temperature of binary Sm2Co17. Both the crushed single crystalline powder x-ray diffraction (XRD) and single crystalline XRD data revealed the Th2Zn17 type rhombohedral(R-3m) crystal structure. Ta atom is found to be statistically replacing the Co-Co dumbbell with its position being at the center of the dumbbell. The Curie temperature of our lightly Mg and Ta doped Sm2Co17 sample is determined to be ∼1100 K using method of generalized Bloch law fitting of easy axis spontaneous magnetization data.


Three-Dimensional Time-Resolved Trajectories From Laboratory Insect Swarms, Michael Sinhuber, Kasper van der Vaart, Rui Ni, James G. Puckett, Douglas H. Kelley, Nicholas T. Ouellette 2019 Stanford University

Three-Dimensional Time-Resolved Trajectories From Laboratory Insect Swarms, Michael Sinhuber, Kasper Van Der Vaart, Rui Ni, James G. Puckett, Douglas H. Kelley, Nicholas T. Ouellette

Physics and Astronomy Faculty Publications

Aggregations of animals display complex and dynamic behaviour, both at the individual level and on the level of the group as a whole. Often, this behaviour is collective, so that the group exhibits properties that are distinct from those of the individuals. In insect swarms, the motion of individuals is typically convoluted, and swarms display neither net polarization nor correlation. The swarms themselves, however, remain nearly stationary and maintain their cohesion even in noisy natural environments. This behaviour stands in contrast with other forms of collective animal behaviour, such as flocking, schooling, or herding, where the motion of individuals is ...


A Theoretical Model Of Underground Dipole Antennas For Communications In Internet Of Underground Things, Abdul Salam, Mehmet C. Vuran, Xin Dong, Christos Argyropoulos, Suat Irmak 2019 Purdue University

A Theoretical Model Of Underground Dipole Antennas For Communications In Internet Of Underground Things, Abdul Salam, Mehmet C. Vuran, Xin Dong, Christos Argyropoulos, Suat Irmak

Faculty Publications

The realization of Internet of Underground Things (IOUT) relies on the establishment of reliable communication links, where the antenna becomes a major design component due to the significant impacts of soil. In this paper, a theoretical model is developed to capture the impacts of change of soil moisture on the return loss, resonant frequency, and bandwidth of a buried dipole antenna. Experiments are conducted in silty clay loam, sandy, and silt loam soil, to characterize the effects of soil, in an indoor testbed and field testbeds. It is shown that at subsurface burial depths (0.1-0.4m), change in soil ...


Fluorine Chemistry At Extreme Conditions: Possible Synthesis Of Hgf4, Michael G. Pravica, Sarah Schyck, Blake Harris, Petrika Cifligu, Eunja Kim, Brant Billinghurst 2019 University of Neveda, Las Vegas

Fluorine Chemistry At Extreme Conditions: Possible Synthesis Of Hgf4, Michael G. Pravica, Sarah Schyck, Blake Harris, Petrika Cifligu, Eunja Kim, Brant Billinghurst

Physics & Astronomy Faculty Publications

By irradiating a pressurized mixture of a fluorine-bearing compound (XeF2XeF2) and HgF2HgF2 with synchrotron hard x-rays ... (See full text for complete abstract)


Fundamental Limits Of Measuring Single-Molecule Rotational Mobility, Oumeng Zhang, Matthew D. Lew 2019 Washington University in St Louis

Fundamental Limits Of Measuring Single-Molecule Rotational Mobility, Oumeng Zhang, Matthew D. Lew

Electrical & Systems Engineering Publications and Presentations

Various methods exist for measuring molecular orientation, thereby providing insight into biochemical activities at nanoscale. Since fluorescence intensity and not electric field is detected, these methods are limited to measuring even-order moments of molecular orientation. However, any measurement noise, for example photon shot noise, will result in nonzero measurements of any of these even-order moments, thereby causing rotationally-free molecules to appear to be partially constrained. Here, we build a model to quantify measurement errors in rotational mobility. Our theoretical framework enables scientists to choose the optimal single-molecule orientation measurement technique for any desired measurement accuracy and photon budget.


Magnetic Resonance Studies Of Free Radicals Generation And Their Impact In Different Polymers, Sunita Humagain 2019 The Graduate Center, City University of New York

Magnetic Resonance Studies Of Free Radicals Generation And Their Impact In Different Polymers, Sunita Humagain

All Dissertations, Theses, and Capstone Projects

Studies of free radicals in the physics, chemistry, biology, and materials science have contributed to advancements in those fields. The presence of radicals can damage the material and system in some instances and, in some cases, they may enhance the property of the material as well. Knowledge of free radical transformations helps in resilience of certain polymers and inhibition of the oxidation of food and medicine. In this thesis, using the magnetic resonance techniques, EPR and NMR, the generation of free radicals and their effect on the structure of the material is being studied.

Kapton Polyimide (PI, Kapton®) used in ...


A Hydrogen-Bond Stabilized Mechanism Of Oxygen Evolution In Photosystem Ii: A Proposed Computational Experiment, Christopher King 2019 University of Montana, Missoula

A Hydrogen-Bond Stabilized Mechanism Of Oxygen Evolution In Photosystem Ii: A Proposed Computational Experiment, Christopher King

Undergraduate Theses and Professional Papers

The ability of plants to take in water and release oxygen into the atmosphere is crucial to the survival of life on Earth. During photosynthesis, water is oxidized to O2 (dioxygen) at the Oxygen Evolving Complex (OEC) of Photosystem II. Structurally, the OEC resembles a box with an open lid, consisting of metal atoms (four manganese and one calcium) bridged by oxygen atoms. The mechanism of action of this complex, however, is not well understood. Various mechanisms have been proposed in recent years to explain how the OEC oxidizes water to dioxygen, but all of these mechanisms contain gaps ...


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