Open Access. Powered by Scholars. Published by Universities.®

Physics Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 6 of 6

Full-Text Articles in Physics

Advanced Dual Beam Optical Tweezers For Undergraduate Biophysics Research, Brian Daudelin Dec 2016

Advanced Dual Beam Optical Tweezers For Undergraduate Biophysics Research, Brian Daudelin

Honors Program Theses and Projects

Optical tweezing is a modern physics technique which allows us to use the radiation pressure provided from laser beams to trap very small microscopic particles. In the last two decades optical tweezers have been used extensively in biophysics and atomic physics to study the building blocks of our world on the cellular and quantum levels. Our goal is to construct a dual beam optical tweezers for future undergraduate biophysical research. In this thesis we discuss how the construction and assembly of the dual beam optical tweezers is done from start to finish. Construction consisted of assembling a polarization maintaining laser. …


Quantifying The Dna Binding Properties Of The Binuclear Ruthenium Complex Λλ-P, Nicholas Bryden Dec 2016

Quantifying The Dna Binding Properties Of The Binuclear Ruthenium Complex Λλ-P, Nicholas Bryden

Honors Program Theses and Projects

Threading intercalators are small molecules that bind to DNA by threading their side chains through the DNA bases to intercalate their middle planar section between the DNA base pairs. The high binding affinity and slow dissociation rates of threading intercalators have put them in the class of prospective anti-cancer drugs. In this study we explore the binding of a specific threading intercalator, a binuclear ruthenium complex ΛΛ-P (ΛΛ-[μ-bidppz(phen)4Ru2]4+) using optical tweezers. A single DNA molecule is held at a constant force and the small molecules are introduced to the system in various concentrations until equilibrium is achieved. Measurements of DNA …


Quantum Field Theory And Jet Phenomena, David Elofson May 2016

Quantum Field Theory And Jet Phenomena, David Elofson

Honors Program Theses and Projects

This honors thesis studies graduate-level quantum field theory including Feynman diagrams and Feynman calculus in order to connect experimental results with the theoretical background. It discusses results of a research experience for undergraduates through Duke University's high energy physics program regarding jet phenomena and explains the inadequacy of quantum mechanics in predicting particle interactions. It follows the canonical method of building a relativistic quantum field theory and describes the process for building one from Langrangians. It addresses the non-interacting part of the theory using the canonical quantization and uses the Feynman propagator and Wick's theorem to address the interacting part …


Multi-Frequency Ferromagnetic Resonance Investigation Of Nickel Nanocubes Encapsulated In Diamagnetic Magnesium Oxide Matrix, Saritha Nellutla, Sudhakar Nori, Srinivasa R. Singamaneni, John T. Prater, Jagdish Narayan, Alix I. Smirnov Jan 2016

Multi-Frequency Ferromagnetic Resonance Investigation Of Nickel Nanocubes Encapsulated In Diamagnetic Magnesium Oxide Matrix, Saritha Nellutla, Sudhakar Nori, Srinivasa R. Singamaneni, John T. Prater, Jagdish Narayan, Alix I. Smirnov

Chemical Sciences Faculty Publications

Partially aligned nickel nanocubes were grown epitaxially in a diamagnetic magnesium oxide (MgO:Ni) host and studied by a continuous wave ferromagnetic resonance (FMR) spectroscopy at the X-band (9.5 GHz) from ca. 117 to 458 K and then at room temperature for multiple external magnetic fields/resonant frequencies from 9.5 to 330 GHz. In contrast to conventional magnetic susceptibility studies that provided data on the bulk magnetization, the FMR spectra revealed the presence of three different types of magnetic Ni nanocubes in the sample. Specifically, three different ferromagnetic resonances were observed in the X-band spectra: a line 1 assigned to large nickel …


Mechanisms Of Small Molecule-Dna Interactions Probed By Single-Molecule Force Spectroscopy, Ali A. Almaqwashi, Thayaparan Paramanathan, Ioulia Rouzina, Mark C. Williams Jan 2016

Mechanisms Of Small Molecule-Dna Interactions Probed By Single-Molecule Force Spectroscopy, Ali A. Almaqwashi, Thayaparan Paramanathan, Ioulia Rouzina, Mark C. Williams

Physics Faculty Publications

There is a wide range of applications for non-covalent DNA binding ligands, and optimization of such interactions requires detailed understanding of the binding mechanisms. One important class of these ligands is that of intercalators, which bind DNA by inserting aromatic moieties between adjacent DNA base pairs. Characterizing the dynamic and equilibrium aspects of DNA-intercalator complex assembly may allow optimization of DNA binding for specific functions. Single-molecule force spectroscopy studies have recently revealed new details about the molecular mechanisms governing DNA intercalation. These studies can provide the binding kinetics and affinity as well as determining the magnitude of the double helix …


Biophysical Measurements Of Cells, Microtubules, And Dna With An Atomic Force Microscope, Luka M. Devenica, Clay Contee, Raysa Cabrejo, Matthew Kurek, Edward F. Deveney, Ashley R. Carter Jan 2016

Biophysical Measurements Of Cells, Microtubules, And Dna With An Atomic Force Microscope, Luka M. Devenica, Clay Contee, Raysa Cabrejo, Matthew Kurek, Edward F. Deveney, Ashley R. Carter

Physics Faculty Publications

Atomic force microscopes (AFMs) are ubiquitous in research laboratories and have recently been priced for use in teaching laboratories. Here, we review several AFM platforms and describe various biophysical experiments that could be done in the teaching laboratory using these instruments. In particular, we focus on experiments that image biological materials (cells, microtubules, and DNA) and quantify biophysical parameters including membrane tension, persistence length, contour length, and the drag force.