A hybrid computational model of bursting neurons
Barbara Breen

Bursting neurons, neurons that fire in rhythmic clusters, are the
pacemakers of any neurological system. The frequency of bursting may
control activities from breathing to digestion to locomotion to the
circadian cycle. Modeling such neurons computationally presents
unique challenges, and there are any number of simplified models in
use that allow for computational ease of integration. The drawback of
these simpler, "integrate-and-fire" models is quite literally that
the simpler the model, the less physiological relevance it has.

While the mechanics of neuron firing is well-described by the
differential equations that describe an RC circuit, it isn't unusual
to find four orders of magnitude difference in the  time scales
operating within a single bursting neuron. This feature requires the
implementation of algorithms that can estimate rate of change over
several variables in advance of each computational step -- an
expensive price in terms of computational speed and efficiency.

I will describe an analysis of a bursting neuron that utilizes tools
from nonlinear dynamics (parameterization and bifurcation diagram)
that allow me to simplify a complex neuron model without compromising
its physiological relevance. This "hybrid" model, a unique
combination of the "RC circuit" with the "integrate-and-fire" models,
gives us the opportunity to model larger networks of bursting neurons
with excellent computational efficiency.


What If Radiation is Actually GOOD For You?
Ed Hiserodt

Regulations for radiation safety have long been based on the Linear
No-Threshold (LNT) Theory.  A wealth of experimental and statistical data
proves that below 10 cSv (10 rems) radiation is not only not harmful, but
has a beneficial effect known as hormesis-a stimulation of the immune system
by small doses of an agent that is injurious at high levels.  The talk draws
on some of the more than 160 studies cited in the book and goes into detail
on several of them, including a comprehensive radon study using data from
1900 U.S. Counties.


VORE TASKS & INSTANT NOTE CAPTURE:
New Software Tools Coming Soon To Your Classroom
Toby Dittric

When was the last time you assigned oral homework or gave an oral examination? When was the last time you modified your PowerPoint lecture presentations? How often do you modify your PowerPoint lectures? Perhaps what is needed is the newly invented software technology described in this presentation. This software technology is currently Patent Pending in the USPTO with International Patent Rights reserved. This presentation is the first public disclosure of these inventions.


Becoming a Medical Physicist
Jeff Limmer

In this section the learner will be exposed to the pathways
which lead to the profession of Medical Physics. This includes the
traditional, accredited programs, the coursework and experience
required; as well as the non-traditional routes through other
professions and residencies. If there is time, there will also be an
example of how this training is applied in the workplace.


The Role of Mechanical Stimuli on Heart Development
Sandra Rugonyi, PhD

Mechanical forces acting on a cell influence the cell’s “behavior”. When mechanical forces change, cells respond by generating a cascade of signaling and gene expression events that lead to cellular adaptation to the new conditions. In tissues, these adaptations manifest, for instance, as changes in morphology and tissue elasticity. Blood flow exerts pressure and shear forces on the walls of the cardiovascular system, including the heart, and these forces affect cellular response and ultimately cardiovascular function. This is also true during embryonic development, when deviations from normal blood flow conditions could lead to congenital heart disease. Although it has been shown that changes in hemodynamic conditions during development produce a spectrum of heart defects, the mechanisms by which mechanical forces alter the development of the heart are still not well understood. Progress towards understanding this mechanisms has been halted by challenging measurements of heart movement, blood flow velocities and flow-induced forces in embryos in vivo. Our objective is to quantify flow-induced forces, during normal and altered hemodynamic conditions, and predict the effect of these forces on heart development. To this end, we study the heart of chick embryos that have been incubated for approximately 3.5 days of a 21-day incubation period. At this developmental stage, the chick heart is beating but only consists of a looped tube, which has a primitive atrium followed by a ventricle. We focus on models of the heart outflow tract (OFT), which connects the primitive ventricle with the arterial sac from which blood is distributed to the chick circulatory system. To better characterize flow-induced forces in vivo, we use a combination of experimental data and numerical modeling of the heart. The movement of the OFT wall during the cardiac cycle is captured with optical coherence tomography (OCT) imaging techniques, and pressure in the ventricle is measured using a servo-null system. These data are incorporated into finite element models of the OFT, from which flow-induced mechanical forces can be quantified. A future step is to correlate flow-induced mechanical forces with cell proliferation and gene expression patterns under normal and altered blood flow conditions to unravel the mechanisms by which deviations from normal hemodynamic conditions during development lead to congenital heart disease.


Fusion: The Unlikely Union of Physics and English Comp
Åsa Bradley

Learning communities invigorate teaching and enhance student learning by enabling students to discover connections between disciplines and increasing their critical thinking skills. This style of teaching also fosters collaboration and leadership in the classroom, which are critical to any student-centered active learning environment.

During this talk I’ll share lessons learned while team teaching a physics survey class English composition. I’ll show our planning process for integrating the two disciplines, share some of our assignments and activities we used in the classroom, as well as describe how we divided up the lesson time. Come find out how you can implement this tremendously beneficial and fun way of teaching on your campus.


In Vivo Optical Spectroscopy for the Diagnosis and Management of Disease: an Industrial Perspective
Ed Hull

Optical methods have long held promise in the areas of disease diagnosis
and management due to their potential for rapid delivery of information
specific to the chemistry and morphology of biological tissues. Bringing
a particular technology to the marketplace necessitates facing a range
of challenges beyond scientific proof-of-principle related to device
cost, size, ruggedness, and accurate performance over a broad range of
users and operating conditions. In this talk, a general introduction
will be given to the field of tissue optics as it relates to medical
device development for disease diagnosis. The research and development,
engineering, and regulatory hurdles faced by two very different optical
diagnostic technologies will then be addressed. The first instrument
exploits noninvasive fluorescence spectroscopy of the skin for detection
of undiagnosed Type II diabetes, the incidence of which is rising in
truly epidemic proportions in the United States and throughout the
world. The second device is a near-infrared scanning spectroscopic
cardiac catheter system for detection of lipid-rich atherosclerotic
plaques in vivo. For both systems, the diagnostic accuracy of
currently-accepted detection schemes will be reviewed, and the
motivation for an optical solution addressed. A review of the tissue
optical properties and user requirements governing the design of the
devices will be presented, and results of recent clinical studies will
be summarized. Some considerations for undergraduates seeking to enter
the medical device workplace will also be offered.