About me
I am an assistant professor in the physics department at California State University at Northridge. See my CV for more technical details about my professional existence. My contact information is:
Contact:
Phone: 818 677 4124 :::: email: yshiferaw at csun.edu
Research
I am interested in the application of nonlinear dynamics and pattern formation to problems in biology. Much of my work revolves around the application of these methods to understand the dynamics that underlies abnormal cardiac rhythms which precede a heart attack. This work involves a wide range of scales ranging from the ion channels that regulate the electrical activity in heart cells, to the dynamics of spiral waves in the whole heart. Remarkably, ideas from physics and mathematics are essential for a complete understanding of these biological phenomena, which is critical in order to develop rational treatments. Recently I have also started to look into the application of stochastic processes to shed light on random arrhythmogenic sub-cellular activity in heart cells. My work involves a combination of numerical computation and some analytics, and is also firmly grounded in experimental work.
To learn more about my research work browse through my PUBLICATIONS. Click on the publication links and you should be able to download PDFs of my papers.
Teaching
I am teaching physics 100a this semester. The website for my MWF 12:00-12:50 class is here. For my TH 7:00-8:15 class click here.
I am currently looking for some research students. If you are an undergraduate or graduate student interested in computational biology/biophysics feel free to email me.
Cardiac Cell Models
Click HERE to got to the cell model page where you can download the latest SHIF-FOX cardiac cell model. Also included is a background and description of the model. I have included a cardiac cable code so users can explore its features. Researchers are free to use this code (providing you cite our papers!). Please email me if you have questions or comments about the model.
Gallery
The picture on the left is a rabbit heart (courtesy of Hideki Hayashi at Cedars Sinai). At sites a,b and c, alternans of the calcium transient are observed. However, alternans change phase along the nodal line at b. On the right is a fluoresence image of the amplitude of calcium alternans showing the location of the nodal line. This is a fascinating example of pattern formation in the heart, and may shed light on the genesis of arrhythmias.
Some Useful Links
I usually navigate the biophysics literature using PUBMED and the new google-scholar.
The very useful "Handbook of Mathematical Functions", by Abramowitz and Stegun, is online!
A great online textbook, written by a nobel laureate, on the eye and brain
For physics preprints see the Los Alamos Archives.
Some Talks
My talk on the Turing instability in cardiac cells, and a recent talk at KITP on some older work on calcium cycling in cardiac cells.
Talk on our work on stochastic calcium signaling in cells: stochastic signaling.
Some resources
Bellow are some accessible introductory lecture slides by experts in the field (all of these are already in the public domain).
1 Excellent article by Professor Francisco Bezanilla on the "Molecular Basis of Excitability". Excellent introduction, by an expert in the field, on how ion channels regulate the electrical potential across cells.
2. Elizabeth Cherry and Flavio Fenton at Cornell have put together a nice collections of Java applets on various aspects of excitable media and cardiac dynamics. Check out their website here.
3. Professor Jim Weiss of UCLA has given some excellent talks on the application of dynamical systems to cardiac arrhythmias. Download them here, and here.
4. Dr. Igor Efimov also has some very nice slides on basic cell architecture and its relevance to cardiac function. He has a webpage with some nice introductory slides.
5. Professor Charles Peskin at the Courant institute has some nice introductory slides on his website.
6. Excellent resource on various biophysical topics at the biophysical society site. Some nice texts which can be downloaded free.
7. A nice article by Alain Karma and Robert Gilmour (Physics Today) on pattern formation in the heart.
8. A very nice ppt slide, by Professor Robert Kass, on the Hodgkin-Huxley equations. A nice introduction to this classic work.
9. Alponso Bueno has written a very nice chapter on basic modeling of cardiac electrophysiology in his thesis here. Overall this is well written and quite informative.
10. Don Bers has written a nice review article on calcium cycling and arryhthmias.
