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Biological and Chemical Physics Commons

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Characterization Of Neutron And Proton Exposure On The Radiation Resistant Bacterium, Deinococcus Radiodurans, Ronald C. Lenker 2017 Air Force Institute of Technology

Characterization Of Neutron And Proton Exposure On The Radiation Resistant Bacterium, Deinococcus Radiodurans, Ronald C. Lenker

Theses and Dissertations

Deinococcus radiodurans is a robust bacterium that is known for its extraordinary resistance to ionizing radiation. In general, many of the investigations of this bacterium's resistance have revolved around low linear energy transfer radiation, such as gamma and electron radiation. This study explored Deinococcus radiodurans's ability to survive high linear energy transfer radiation, specifically proton and neutron radiation. Deinococcus radiodurans was dehydrated to reduce the effects of low linear energy transfer radiation. The bacteria were exposed to both neutron and proton radiation of varying amounts and rehydrated. The resulting colonies were counted and compared to colonies of non-irradiated ...


Molecular Dynamics Investigations Of Structural Conversions In Transformer Proteins, Jeevan GC 2017 Florida International University

Molecular Dynamics Investigations Of Structural Conversions In Transformer Proteins, Jeevan Gc

FIU Electronic Theses and Dissertations

Multifunctional proteins that undergo major structural changes to perform different functions are known as “Transformer Proteins”, which is a recently identified class of proteins. One such protein that shows a remarkable structural plasticity and has two distinct functions is the transcription antiterminator, RfaH. Depending on the interactions between its N-terminal domain and its C-terminal domain, the RfaH CTD exists as either an all-α-helix bundle or all-β-barrel structure. Another example of a transformer protein is the Ebola virus protein VP40 (eVP40), which exists in different conformations and oligomeric states (dimer, hexamer, and octamer), depending on the required function.I performed Molecular ...


Removal Of Chlorine From Chlorine-Nitrogen Mixture In A Film Of Liquid Water, Sarwan S. Sandhu 2017 University of Dayton

Removal Of Chlorine From Chlorine-Nitrogen Mixture In A Film Of Liquid Water, Sarwan S. Sandhu

Sarwan S. Sandhu

In industry there are many examples of absorption of a gas with or without chemical reaction in the liquid phase. In physical absorption, a particular gaseous component is removed from a gas mixture due to its larger solubility in the liquid phase solvent. The removal of butane and pentane from a refinery gas mixture by a heavy oil in the liquid phase is an example of physical absorption. In absorption with chemical reaction, the gaseous component to be removed transfers across the gas-liquid interface due to a difference in the bulk chemical potentials or concentrations in the two phases. The ...


Improving Sers-Based Readout Strategy For Biomarker Detecting Immunoassays, Joseph Smolsky 2017 U.N.O. Physics Department

Improving Sers-Based Readout Strategy For Biomarker Detecting Immunoassays, Joseph Smolsky

Student Research and Creative Activity Fair

Detection and monitoring of disease biomarkers increases probability of successful disease treatment. Surface enhanced Raman scattering (SERS) has several advantages over conventional readout strategies utilized in detecting immunoassays. SERS provides a method for chemical characterization based on molecular vibrational spectra. Raman signals are typically weak and need to be enhanced. This can be done using plasmons in nanoparticles of noble metals, we use gold (Au). Molecules with known spectra, Raman reporter molecules (RRM), can be adsorbed to Au nanoparticles. This enhances the Raman signal of the RRM when illuminated by a laser of optimal wavelength. Adding antibodies to nanoparticles modified ...


Higher-Order Power Harmonics Of Pulsed Electrical Stimulation Modulates Corticospinal Contribution Of Peripheral Nerve Stimulation, Chiun-Fan Chen, Marom Bikson, Li-Wei Chou, Chunlei Shan, Niranjan Khadka, Wen-Shiang Chen, Felipe Fregni 2017 Loyola University Chicago

Higher-Order Power Harmonics Of Pulsed Electrical Stimulation Modulates Corticospinal Contribution Of Peripheral Nerve Stimulation, Chiun-Fan Chen, Marom Bikson, Li-Wei Chou, Chunlei Shan, Niranjan Khadka, Wen-Shiang Chen, Felipe Fregni

Engineering Science Faculty Publications

It is well established that electrical-stimulation frequency is crucial to determining the scale of induced neuromodulation, particularly when attempting to modulate corticospinal excitability. However, the modulatory effects of stimulation frequency are not only determined by its absolute value but also by other parameters such as power at harmonics. The stimulus pulse shape further influences parameters such as excitation threshold and fiber selectivity. The explicit role of the power in these harmonics in determining the outcome of stimulation has not previously been analyzed. In this study, we adopted an animal model of peripheral electrical stimulation that includes an amplitude-adapted pulse train ...


The Impact Of Base Stacking On The Conformations And Electrostatics Of Single-Stranded Dna, Alex Plumridge, Steve P. Meisburger, Kurt Andresen, Lois Pollack 2017 Cornell University

The Impact Of Base Stacking On The Conformations And Electrostatics Of Single-Stranded Dna, Alex Plumridge, Steve P. Meisburger, Kurt Andresen, Lois Pollack

Physics and Astronomy Faculty Publications

Single-stranded DNA (ssDNA) is notable for its interactions with ssDNA binding proteins (SSBs) during fundamentally important biological processes including DNA repair and replication. Previous work has begun to characterize the conformational and electrostatic properties of ssDNA in association with SSBs. However, the conformational distributions of free ssDNA have been difficult to determine. To capture the vast array of ssDNA conformations in solution, we pair small angle X-ray scattering with novel ensemble fitting methods, obtaining key parameters such as the size, shape and stacking character of strands with different sequences. Complementary ion counting measurements using inductively coupled plasma atomic emission spectroscopy ...


Simulation Model Of An Automatic Commercial Ice Machine, Haithem Murgham, David Myszka, Vijay Bahel, Rajan Rajendran, Kurt Knapke, Suresh Shivashankar, Kyaw Wynn 2017 University of Dayton

Simulation Model Of An Automatic Commercial Ice Machine, Haithem Murgham, David Myszka, Vijay Bahel, Rajan Rajendran, Kurt Knapke, Suresh Shivashankar, Kyaw Wynn

David Myszka

Automatic commercial ice-making machines that produce a batch of cube ice at regular intervals are known as “cubers." Such machines are commonly used in food service, food preservation, hotel, and health service industries. The machines are typically rated for the weight of ice produced over a 24-hour period at ambient air temperatures of 90°F and water inlet temperature of 70°F.

These cubers typically utilize an air-cooled, vapor-compression cycle to freeze circulating water flowing over an evaporator grid. Once a sufficient amount ice is formed, a valve switches to enable a harvest mode, where the compressor’s discharge gas ...


Student Resources For: From Photon To Neuron, Light, Imaging, Vision, Philip C. Nelson 2017 University of Pennsylvania

Student Resources For: From Photon To Neuron, Light, Imaging, Vision, Philip C. Nelson

Department of Physics Papers

This zip archive contains datasets and additional media associated to the book "From Photon to Neuron (Princeton University Press, 2017).


Second Harmonic Generation – A Novel Approach In Retinal Imaging, Denis Y. Sharoukhov 2017 The Graduate Center, City University of New York

Second Harmonic Generation – A Novel Approach In Retinal Imaging, Denis Y. Sharoukhov

All Dissertations, Theses, and Capstone Projects

Here we present the utilization of Second Harmonic Generation (SHG) for label-free imaging of microtubules (MTs) in the retinal nerve fiber layer (RNFL). MTs are an important part of axonal cytoskeleton, providing structural support and serving as a railroad in intracellular transport. We demonstrate the application of SHG microscopy to the following studies: 1) Can changes in MT conformation be detected when treated with a stabilizing drug (Taxol); 2) if disruption in MT precedes loss of axons in a mouse model of glaucoma (DBA/2J); and 3) if elevated levels of intraocular pressure affect MT integrity. Our results validate SHG ...


Tracer Counterpermeation Analysis Of Diffusivity In Finite-Length Nanopores With And Without Single-File Dynamics, David Ackerman, James W. Evans 2017 Iowa State University

Tracer Counterpermeation Analysis Of Diffusivity In Finite-Length Nanopores With And Without Single-File Dynamics, David Ackerman, James W. Evans

Physics and Astronomy Publications

We perform a tracer counterpermeation (TCP) analysis for a stochastic model of diffusive transport through a narrow linear pore where passing of species within the pore is inhibited or even excluded (single-file diffusion). TCP involves differently labeled but otherwise identical particles from two decoupled infinite reservoirs adsorbing into opposite ends of the pore, and desorbing from either end. In addition to transient behavior, we assess steady-state concentration profiles, spatial correlations, particle number fluctuations, and diffusion fluxes through the pore. From the profiles and fluxes, we determine a generalized tracer diffusion coefficient Dtr(x), at various positions x within the pore ...


C.V. - Wojciech Budzianowski, Wojciech M. Budzianowski 2017 Wojciech Budzianowski Consulting Services

C.V. - Wojciech Budzianowski, Wojciech M. Budzianowski

Wojciech Budzianowski

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Renewable Energy And Sustainable Development (Resd) Group, Wojciech M. Budzianowski 2017 Wroclaw University of Technology

Renewable Energy And Sustainable Development (Resd) Group, Wojciech M. Budzianowski

Wojciech Budzianowski

No abstract provided.


Including Wrist Flexion In The Human Arm Model Changes Everything!, William B. Laing III, Austin Johnson, Albert D. Gonzalez, Chris S. Hansen 2017 Southern Adventist University

Including Wrist Flexion In The Human Arm Model Changes Everything!, William B. Laing Iii, Austin Johnson, Albert D. Gonzalez, Chris S. Hansen

Faculty Works

Does your introductory physics laboratory experiment that analyzes the human arm as a lever assume an inflexible wrist? If so, the analysis of the biceps force required to perform a biceps curl will lead to results that contradict experience: one does not expect the required biceps force to decrease as the mass is raised. We will show that allowing for wrist flexion leads to agreement with empirical data: that the required force does increase as the mass is raised if the wrist angle is allowed to be optimal.


Application Of The Fisher Dimer Model To Dna Condensation, John C. Baker III 2017 VCU

Application Of The Fisher Dimer Model To Dna Condensation, John C. Baker Iii

Theses and Dissertations

This paper considers the statistical mechanics occupation of the edge of a single helix of DNA by simple polymers. Using Fisher's exact closed form solution for dimers on a two-dimensional lattice, a one-dimensional lattice is created mathematically that is occupied by dimers, monomers, and holes. The free energy, entropy, average occupation, and total charge on the lattice are found through the usual statistical methods. The results demonstrate the charge inversion required for a DNA helix to undergo DNA condensation.


Competing Theories Of Pitch Perception: Frequency And Time Domain Analysis, Nowell Thacher Stoddard 2017 Bard College

Competing Theories Of Pitch Perception: Frequency And Time Domain Analysis, Nowell Thacher Stoddard

Senior Projects Spring 2017

Pitch perception is a phenomenon that has been the subject of much debate within the psychoacoustics community. It is at once a psychological, physiological and mathematical issue that has divided scientists for the last 200 years. My project aims to investigate the benefits and shortcomings of both the place theory and time theory approaches. This is done first by a model consistent with the long-standing focus on the frequency domain, and then by expanding to a more modern approach that functions in the time domain.


Dynamics Of Mitotic Microtubules In Fission Yeast, Patrick Flynn 2017 University of Colorado, Boulder

Dynamics Of Mitotic Microtubules In Fission Yeast, Patrick Flynn

Undergraduate Honors Theses

Microtubules (MTs) are cytoskeletal polymers that assemble into a biomechanical complex known as the mitotic spindle. The spindle is responsible for the equal partitioning of chromosomes during cell division; an event known as mitosis. The dependence of proper chromosome segregation on the dynamics of individual microtubules (MTs) is not well understood or easy to study due to their small size and quick dynamics. Mathematical models and simulations have been constructed in order to better understand the physical basis of how the mitotic spindle accurately, or inaccurately, divides duplicated chromosomes during mitosis. These models rely on the dynamics parameters of individual ...


Design And Activation Of Frequency Tunable 200ghz Gyrotron, Natalie Golota, Faith Scott, Edward Saliba, Brice Albert, Alexander Barnes 2017 Washington University in St. Louis

Design And Activation Of Frequency Tunable 200ghz Gyrotron, Natalie Golota, Faith Scott, Edward Saliba, Brice Albert, Alexander Barnes

Undergraduate Research Symposium Posters

Dynamic Nuclear Polarization (DNP) when combined with Nuclear Magnetic Resonance (NMR) yields high sensitivity spectra while decreasing sample acquisition time. DNP transfers polarization from electron to nuclear spins, giving a strong enhancement of NMR signal. DNP is rapidly developing area of research due in part to application of cyclotron resonance masers (gyrotron) as high power microwave sources. Gyrotrons provide a high-power, high-frequency microwave source that can be used in close proximity to high field NMR magnets. Gyrotrons are operated under strong vacuum and within a cryogenic superconducting magnetic. Gyrotron microwave power is generated by a magnetron injection gun (MIG) composed ...


Rules And Mechanisms For Efficient Two-Stage Learning In Neural Circuits, Tiberiu Teşileanu, Bence Ölveczky, Vijay Balasubramanian 2017 CUNY Graduate Center, University of Pennsylvania

Rules And Mechanisms For Efficient Two-Stage Learning In Neural Circuits, Tiberiu Teşileanu, Bence Ölveczky, Vijay Balasubramanian

Publications and Research

Trial-and-error learning requires evaluating variable actions and reinforcing successful variants. In songbirds, vocal exploration is induced by LMAN, the output of a basal ganglia-related circuit that also contributes a corrective bias to the vocal output. This bias is gradually consolidated in RA, a motor cortex analogue downstream of LMAN. We develop a new model of such two-stage learning. Using stochastic gradient descent, we derive how the activity in ‘tutor’ circuits (e.g., LMAN) should match plasticity mechanisms in ‘student’ circuits (e.g., RA) to achieve efficient learning. We further describe a reinforcement learning framework through which the tutor can build ...


Analyses Of Densely Crosslinked Phenolic Systems Using Low Field Nmr, Jigneshkumar Patel 2017 University of Massachusetts, Amherst

Analyses Of Densely Crosslinked Phenolic Systems Using Low Field Nmr, Jigneshkumar Patel

Doctoral Dissertations

A uniform dispersion of reactants is necessary to achieve a complete reaction involving multi-components, especially for the crosslinking of rigid high-performance materials. In these reactions, miscibility is crucial for curing efficiency. This miscibility is typically enhanced by adding a third component, a plasticizer. For the reaction of the highly crystalline crosslinking agent hexamethylenetetramine (HMTA) with a strongly hydrogen-bonded phenol formaldehyde resin, furfural has been traditionally used as the plasticizer. However, the reason for its effectiveness is not clear. In this doctoral thesis work, miscibility and crosslinking efficiency of plasticizers in phenolic curing reactions are studied by thermal analysis and spectroscopic ...


Characterization Of The Atcc Α-Tc1-6 Pancreatic Alpha Cell Line To Study Glucagon Secretion, Larissa M. Ikenouye 2017 University of Denver

Characterization Of The Atcc Α-Tc1-6 Pancreatic Alpha Cell Line To Study Glucagon Secretion, Larissa M. Ikenouye

Electronic Theses and Dissertations

The endocrine pancreas is responsible for maintaining glycemic equilibrium in the body. Given the importance of this blood-glucose homeostasis and the implication an unbalance has on Diabetes mellitus, the study of the glucose-sensing alpha and beta cells in the pancreas is a popular field for scientific researchers. In this study, we use immunofluorescence, qPCR analysis, intracellular calcium experiments, and biochemical glucagon secretion assays to determine if the commercially available tumor cell line clone, α-TC1-6 obtained from American Type Culture Collection, is an appropriate model system for glucagon secretion in pancreatic alpha cells. We confirm the production of the hormone peptide ...


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