Bulletin of the American Physical Society
Annual Meeting of the Four Corners Section of the APS
Volume 57, Number 11
Friday–Saturday, October 26–27, 2012; Socorro, New Mexico
Session J1: Biophysics |
Hide Abstracts |
Chair: Gus Hart, Brigham Young University Room: Macey Center Galena |
Saturday, October 27, 2012 1:30PM - 1:42PM |
J1.00001: Microfluidics Gas Dynamic Virtual Nozzle Garrett Nelson, Fernada Camacho-Alanis, John Spence, Uwe Weierstall, Alexandra Ros, Bruce Doak The Gas Dynamic Virtual Nozzle (GDVN) is a microscopic liquid droplet injector that utilizes a gas focusing sheath to run a continuous supply of hydrated bioparticles in vacuum across a pulsed X-ray beam. Its ability to run for days without clogging make it an ideal injector for next-generation biological imaging techniques such as serial femtosecond crystallography (SFX). We report a new approach to nozzle fabrication that has significantly extended the injector's capabilities. Soft photolithography was used to produce a microfluidics version that is comparable to the standard GDVN but capable of subsonic operation and fast fluid switching -- desirable features for increasing data yield by reducing wasted sample. [Preview Abstract] |
Saturday, October 27, 2012 1:42PM - 1:54PM |
J1.00002: Non-Invasive Glucose Measurement: A Brief Review of Methods, from a Physics Perspective Daniel Blakley, Steven Simske, Pankaj Vadgama This presentation reviews many of the key pioneering methods for non-invasive glucose measurements that have been attempted to date, discussing principles of operation particularly with respect to the physics involved. [Preview Abstract] |
Saturday, October 27, 2012 1:54PM - 2:06PM |
J1.00003: New Advances in Cardiology Signal Processing Daniel Blakley, Steven Simske This presentation introduces a new advanced cardiology signal processing method to address the inherent problems that have plagued such measurements for over 60 years. [Preview Abstract] |
Saturday, October 27, 2012 2:06PM - 2:18PM |
J1.00004: Biophysical Studies of Function and Stability in Adenylosuccinate Lyase Stephen Ray, Nathan Duval, Terry Wilkinson II, Sean Shaheen, Kinshuk Ghosh, David Patterson Adenylosuccinate Lyase (ADSL) is a homotetrameric protein with four active sites that accommodate two reactions in the de novo purine biosynthesis pathway. ~It catalyzes the conversion of SAICAR to AICAR and AMPS to AMP. ~Point mutations in the gene encoding the protein ADSL lead to ADSL deficiency, a disorder characterized by serious neurological and physiological symptoms. ~Two leading hypotheses regarding the pathogenesis are ``Loss of Function'' or ``Gain in Toxic Function.'' ~These hypotheses can be related to the reduction of either the enzyme kinetics or the stability of the tetramer structure. ~Enzymatic studies can be used to provide a quantitative measure of the extent to which the enzyme acts on its designated substrates, SAICAR and AMPS. ~Recent kinetic studies have measured activity only on the substrates independently. ~Here we present characterization of enzyme kinetics for the biophysically interesting and physiologically relevant case where two substrates exhibit competitive binding to the enzyme, for both wild type and disease causing mutants of ADSL. Preliminary data suggest equivalent specific activities may be necessary to suppress severe phenotypes from expressing. Additionally, we will present results on the role of mutations on the thermodynamic stability of the enzyme. We will discuss thermodynamic analysis that gives a direct quantitative measure of the propensity of formation of folded and unfolded states of the protein, which influence the functionality of the protein and may also influence aggregation. [Preview Abstract] |
Saturday, October 27, 2012 2:18PM - 2:30PM |
J1.00005: Modeling Condensation, Hydro- and Pepto-affinity of Surfaces in Medical Implant Devices and Surgical Lenses: Effect of Blood Proteins Ross Bennett-Kennett, Nicole Herbots, Ashlee Murphy, David Sell, Tyler Kutz, Sophia Benitez, Ajjya Acharya, Brett Hughes, Clarizza Watson, Eric Culbertson, Clive Sell, H. Kwong Surgical lenses in laparoscopes and arthroscopes ``fog'' during surgery. Fogging increases by up to 40\% surgery duration, infection rates, and scarring due to exposure from repeated scopes withdrawal for cleaning. Modeling nucleation on surfaces shows that 2-D layer-by-layer condensation maintains transparency while 3-D droplets refract at gas/fluid interfaces leading to opacity or ``fogging.'' This ProteinKnox\texttrademark model for lenses made from bio-compatible polymers, and silica led us to a nano-scale molecular mesh applied as a bio-identical emulsion. ProteinKnox\texttrademark [1-5] meets a 100\% success rate in eliminating fogging for up to 240 minutes over 300 experiments. Twenty surgical trials in the OR yield a success rate of 90\%, with loss of vision due to the presence of blood or blood proteins, not fogging. We studied the common blood protein, heparin, which prevents coagulation, with the ProteinKnox\texttrademark model. Heparin behaves like H2O on hydrophobic surfaces. It does not prevent fogging nor interferes with 2-D condensatio. Next, we investigated fibrinogen as agonist agent because it causes coagulation. Fibrinogen applied to various surfaces in emulsions prepared in accordance with the ProteinKnox\texttrademark model can prevent not only [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700