In Chapter 10 of Intermediate Physics for Medicine and Biology, Russ Hobbie and I discuss negative feedback loops. Feedback is often used to maintain an important variable nearly constant. This idea underlies homeostasis and is fundamental to physiology. "Are Physiological Oscillations Physiological?" by Ivy Xiong and Alan Garfinkel. So imagine my surprise when I read Ivy Xiong and Alan Garfinkel’s topical review in The Journal of Physiology titled “Are Physiological Oscillations Physiological?” (In Press), which changed the way I look at homeostasis and feedback. Its abstract states ..read more

Are Electromagnetic Fields Making Me Ill?, by Brad Roth Every year the Kresge Library at Oakland University hosts an event called “Authors at Oakland” where they honor publications by Oakland University faculty. This year was “a celebration of the book.” Intermediate Physics for Medicine and Biology was featured at a previous Authors at Oakland event, and this year I submitted Are Electromagnetic Fields Making Me Ill? Two authors were selected to give a short talk about their book, and I was one of them. So on Wednesday, March 20 I spoke to an audience of OU librarians, members of t ..read more

Recently I was reading an article by Ramsay Lewis and Yuhong Dong in The Epoch Times titled Invisible Electromagnetic Fields: Do They Harm Your Health? My friend and colleague David Garfinkle once told me that whenever you see a book or article whose title is in the form of a question, the answer is always “no.” I assumed that would be the case for this article, and I began reading. The article describes how citizens of Virginia Beach opposed an offshore renewable energy project, justifying their opposition in part because of possible health hazards from electric and magnetic fields prod ..read more

William Catterall, known as “the father of ion channels,” died on February 28 at the age of 77. Russ Hobbie and I cite Catterall’s article on the structure of sodium ion channels in Chapter 9 of Intermediate Physics for Medicine and Biology. Payandeh J, Scheuer T, Zheng N, Catterall WA (2011) The crystal structure of a voltage-gated sodium channel. Nature 475:353–358. Catterall worked in the intramural program at the National Institutes of Health in the laboratory of Marshall Nirenberg. He then moved to the University of Washington, where he was a professor of Pharmacology for over 40 years. T ..read more

German biophysicist Erwin Neher turned 80 last week. Neher and Bert Sakmann received the 1991 Nobel Prize in Physiology or Medicine for their development of patch clamping: a method to record the current through individual ion channels. Russ Hobbie and I discuss Neher and Sakmann’s work in Chapter 9 of Intermediate Physics for Medicine and Biology. I will turn over the rest of this post to Neher. In the two-minute video below, he offers advice to young scientists.   Erwin Neher's Advice to Young People: From a Nobel Prize Winner  https://www.youtube.com/watch?v=vB3MNPuMFCI   I ..read more

Gene Surdotovich and I are hard at work preparing the 6th edition of Intermediate Physics for Medicine and Biology. One change compared to the 5th edition is that we are redrawing most of the figures using Mathematica. It’s a lot of work, but the revised figures look great and many are in color. One advantage of redrawing the figures is that it forces us to rethink what the figure is all about and if it makes sense. This brings me to Figure 10.13 in the chapter about feedback. Specifically, it is from Section 10.6 about a negative feedback loop with two time constants. Without going into deta ..read more

I've always been fascinated by Stirling’s approximation, ln(n!) = n ln(n) − n, where n! is the factorial. Russ Hobbie and I mention Stirling’s approximation in Appendix I of Intermediate Physics for Medicine and Biology. In the homework problems for that appendix (yes, IPMB does has homework problems in its appendices), a more accurate version of Stirling’s approximation is given as ln(n!) = n ln(n) − n + ½ ln(2π n) . There is one thing that’s always bothered me about Stirling’s approximation: it’s for the logarithm of the factorial, not the factorial itself. So today, I’ll derive an appr ..read more

Intermediate Physics for Medicine and Biology provides, for the first time, a textbook about the role that physics plays in medicine. Well… no. I recently found a textbook that preceded IPMB by over a century. Below is its preface. The fact that a knowledge of Physics is indispensable to a thorough understanding of Medicine has not yet been as fully realized in this country as in Europe, where the admirable works of Desplats and Gariel, of Robertson, and of numerous German writers, constitute a branch of educational literature to which we can show no parallel. A full appreciation of this, th ..read more

Allan was born in Johannesburg, the youngest of three children. He spent his teenage years in Cape Town, and was interested in debating, tennis, and acting. He also loved astronomy, which triggered an interest in physics and mathematics. At the University of Cape Town he studied electrical engineering, following in the footsteps of his father and brother. But he soon abandoned engineering to learn physics and to engage in mountaineering. After he obtained his undergraduate degree, he went to England and studied physics at the Cavendish Laboratory in Cambridge.  He didn’t finish his PhD ..read more

Numerical Methods That Work, by Forman Acton. The American computer scientist Forman Acton died ten years ago this Sunday. In Intermediate Physics for Medicine and Biology, Russ Hobbie and I cite Acton’s Numerical Methods That Work. For readers interested in using computers to model biological processes, I recommend this well written and engaging book. Before he died, Acton donated funds to establish the Forman Acton Foundation. Here is how their website describes his life: Forman Sinnickson Acton was born in Salem City, and he went on to change the world. Born on August 10, 1920, h ..read more