Physics Girl has Long Covid

I’m a fan of Dianna Cowern, better known as Physics Girl, who makes Youtube videos about physics that would be helpful for readers of Intermediate Physics for Medicine and Biology. Three years ago I featured several of her videos in a blog post.

Cowern is suffering from a severe case of long Covid. I’m going to turn this week’s post over to Simone Giertz for an update on Cowern’s health.

An update on Dianna's health, by Simone Giertz.

https://www.youtube.com/watch?v=vydgkCCXbTA

 

 

Cobalt Blues: The Story of Leonard Grimmett, the Man Behind the First Cobalt-60 Unit in the United States

Cobalt Blues,
by Peter Almond.

I recently read Cobalt Blues: The Story of Leonard Grimmett, the Man Behind the First Cobalt-60 Unit in the United States (Springer, 2013), written by Peter Almond. The treatment of cancer using the isotope cobalt-60 is now obsolete, but in the era just after World War II it was cutting-edge technology. In his prologue, Almond writes

[The British medical physicist Leonard George] Grimmett was an expert in the use of radium to treat cancer and in the safe handling and measurement of radiation and radioactive materials in clinical situations. He had spent the best part of his career devising better, safer, and more efficient ways to treat cancer with radiation and he remained in England during [World War II]... Then in 1948 while working for UNESCO in Paris he received an offer he could not refuse the, “…post as physicist to a new ‘Cancer Research Institute and Atomic Center’ in The University of Texas”, one of the original universities in the ORINS [Oak Ridge Institute of Nuclear Studies] consortium. Thus was set in motion the events that would lead Grimmett to Houston, Texas and to be the first person to publish, in 1950, the design of a cobalt-60 radiation therapy unit for the treatment of cancer. For the next 25 years cobalt-60 units would be the mainstay of cancer radiation therapy, treating millions of patients worldwide. Grimmett, however, would not live to see the completion of his work. This is his story.

Grimmett is a fascinating guy. As a young boy he learned to play the piano and was quite good. “He had worked his way through college playing for the silent movies, but with the advent of the ‘talkies,’ he had lost his income. He went to work at Westminster Hospital.” At Westminster and other hospitals he helped develop cancer treatment machines using radium, and later he established the medical physics program at the renowned M. D. Anderson Cancer Center. But he had other talents. He was a pilot, a scriptwriter, a gemologist, and jeweler. He’s remembered today primarily for developing a cobalt-60 therapy machine. Almond writes

It is not known for sure who first had the idea of replacing the radium in teletherapy units with a more suitable and less-expensive artificial radioactive substance. Grimmett, however, had been thinking about it for some years before he went to Houston, and a case can be made that he was the first.

What motivated him to use cobalt? “What Grimmett was looking for was an artificial radioactive isotope with gamma ray energies of 1–5 MeV with as long a half-life as possible that could be made in large quantities at a reasonable price.” He considered using sodium-24 for therapy. After ²⁴Na beta decays it emits two gamma rays with energies of 4.1 and 1.4 MeV (see Fig. 17.9 of Intermediate Physics for Medicine and Biology). However, the half-life of ²⁴Na is only 15 hours. 

The idea that cobalt-60 might be a suitable replacement for radium first occurred to Grimmett while he was reading Physical Review in an air-raid shelter during World War II… Later, after the war, he would have read the paper by J. S. Mitchell in the December 1946 issue of the British Journal of Radiology [82]. This is often cited as the paper that initiated the cobalt-60 era. Mitchell specifically mentions cobalt-60 as a replacement for radium beam therapy, and he gave the half-life as 5.3 years and the gamma ray energies as 1.3 and 1.1 MeV. He also reported that it could be produced in “the pile” (nuclear reactor).

Why did Almond title his book Cobalt Blues? Grimmett had trouble obtaining the needed cobalt-60. It is a by-product of nuclear reactors. He first tried the reactor at Oak Ridge, but ended up getting it from a reactor on Chalk River in Canada. Incidentally, the book cover of Cobalt Blues is a lovely cobalt blue.

Grimmett was not the only person trying to use cobalt-60 to treat cancer. Almond briefly describes the other groups, including one in Canada by Harold Johns, and tries to sort out the various priority claims.

Unfortunately, Grimmett died unexpectedly and never saw his unit in use. His obituary in the Houston Chronicle begins

Doctor Grimmett, Cancer Expert, Dies Suddenly 

Dr. Leonard G. Grimmett, 49, eminent physicist whose work in cancer research at M.D. Anderson Hospital, opened a whole new field of treatment of cancer, died of a heart attack at 1:10 a.m. Sunday at his home, 3238 Ewing.

I enjoyed Almond’s book. I learned much about the early years of the M. D. Anderson Cancer Center and about the issues that must be considered when building radiation therapy units. Readers of IPMB will find Cobalt Blues fascinating.

A Simple Mathematical Function Representing the Intracellular Action Potential

In Problem 14 of Chapter 7 in Intermediate Physics for Medicine and Biology, Russ Hobbie and I chose a strange-looking function to represent the intracellular potential along a nerve axon, v_i(x). It’s zero everywhere except in the range −a < x < a, where it’s

 

 

Why this function? Well, it has several nice properties, which I’ll leave for you to explore in this new homework problem.

Section 7.4

Problem 14 ¼. For the intracellular potential, v_i(x), given in Problem 14

(a) show that v_i(x) is an even function,

(b) evaluate v_i(x) at x = 0,

(c) show that v_i(x) and dv_i(x)/dx are continuous at x = 0, a/2 and a, and

(d) plot v_i(x), dv_i(x)/dx, and d²v_i(x)/dx² as functions of x, over the range −2a < x < 2a.

This representation of v_i(x) has a shape like that of an action potential. Other functions also have a similar shape, such as a Gaussian. But our function is nice because it’s non-zero over only a finite region (−a < x < a) and it’s represented by a simple, low-order polynomial rather than a special function. An even simpler function for v_i(x) would be triangular waveform, like that shown in Figure 7.4 of IPMB. However, that function has a discontinuous derivative and therefore its second derivative is infinite at discrete points (delta functions), making it tricky (but not too tricky) to deal with when calculating the extracellular potential (Eq. 7.21). Our function in Problem 14 ¼ has a discontinuous but finite second derivative.

The main disadvantage of the function in Problem 14 ¼ is that the depolarization phase of the “action potential” has the same shape as the repolarization phase. In a real nerve, the upstroke is usually briefer than the downstroke. The next new homework problem asks you to design a new function v_i(x) that does not suffer from this limitation.

Section 7.4

Problem 14 ½. Design a piecewise continuous mathematical function for the intracellular potential along a nerve axon, v_i(x), having the following properties. 

(a) v_i(x) is zero outside the region −a < x < 2a. 

(b) v_i(x) and its derivative dv_i(x)/dx are continuous. 

(c) v_i(x) is maximum and equal to one at x = 0. 

(d) v_i(x) can be represented by a polynomial b_i + c_i x + d_i x², where i refers to four regions: 

        i = 1,    −a < x < −a/2 

        i = 2, −a/2 < x < 0 

        i = 3,      0 < x < a

        i = 4,      a < x < 2a.

Finally, here’s another function that I’m particularly fond of.

Section 7.4

Problem 14 ¾. Consider a function that is zero everywhere except in the region −a < x < 2a, where it is

(a) Plot v_i(x) versus x over the region −a < x < 2a,

(b) Show that v_i(x) and its derivative are each continuous. 

(c) Calculate the maximum value of v_i(x).

Simple functions like those described in this post rarely capture the full behavior of biological phenomena. Instead, they are “toy models” that build insight. They are valuable tools when describing biological phenomena mathematically.

Abraham Liboff (1927–2023)

Abe Liboff, in his
office at Oakland University

Oakland University physicist Abe Liboff died recently. A notice from President Ora Hirsch Pescovitz, published on the OU website, stated:

It is with deep sadness that I inform you of the death of Professor Emeritus Abraham Liboff who passed away on January 9, 2023. Dr. Liboff joined the Oakland University community in the Department of Physics on August 15, 1972, where he served until his retirement in August 2000.

During his tenure here at OU, Dr. Liboff was Chair of the Department of Physics. He is credited with 111 research publications, more than two dozen patents and nearly 3,400 scholarly citations during his career.

I arrived at OU in 1998, so his time at OU and mine overlapped by a couple years. I remember having a delightful breakfast with him during my job interview. He was one of the founders of OU’s medical physics PhD program that I directed for 15 years. His office was just a few doors down the hall from mine and he helped me get started at Oakland. I’ll miss him.

Although I loved the man, I didn’t love Abe’s cyclotron resonance theory of how magnetic fields interact with biological tissue. It’s difficult to reconcile admiration for a scientist with rejection of his scientific contributions. Rather than trying to explain Abe’s theory, I’ll quote the abstract from his article “Geomagnetic Cyclotron Resonance in Living Cells,” published in the Journal of Biological Physics (Volume 13, Pages 99–102, 1985).

Although considerable experimental evidence now exists to indicate that low-frequency magnetic fields influence living cells, the mode of coupling remains a mystery. We propose a radical new model for electromagnetic interactions with cells, one resulting from a cyclotron resonance mechanism attached to ions moving through transmembrane channels. It is shown that the cyclotron resonance condition on such ions readily leads to a predicted ELF-coupling at geomagnetic levels. This model quantitatively explains the results reported by Blackman et al. (1984), identifying the focus of magnetic interaction in these experiments as K⁺ charge carriers. The cyclotron resonance concept is consistent with recent indications showing that many membrane channels have helical configurations. This model is quite testable, can probably be applied to other circulating charge components within the cell and, most important, leads to the feasibility of direct resonant electromagnetic energy transfer to selected compartments of the cell.

In my book Are Electromagnetic Fields Making Me Ill? I didn’t have the heart to attack Abe in print. When discussing cyclotron resonance effects, I cited the work of Carl Blackman instead, who proposed a similar theory. What’s the problem with this idea? If you calculate the cyclotron frequency of a calcium ion in the earth’s magnetic field, you get about 23 Hz (see Eq. 8.5 in Intermediate Physics for Medicine and Biology). However, the thermal speed of a calcium ion at body temperature is about 440 m/s (Eq. 4.12 in IPMB). At that speed, the radius of the cyclotron orbit would be 3 meters (roughly ten feet)! The mean free path of a ion in water, however, is about an angstrom, which means the ion will suffer more than a billion collisions in one orbit; these interactions should swamp any cyclotron motion. Moreover, ion channels have a size of about 100 angstroms. In order to have a orbital radius similar to the size of a ion channel, the calcium ion would need to be moving extremely fast, which means it would have a kinetic energy vastly larger than the thermal energy. The theory just doesn’t work.

Since Liboff isn’t around to defend himself, I’ll let Louis Slesin—the editor and publisher of Microwave News—tell Abe’s side of the story. Read Slesin’s Reminiscence on the Occasion of Abe Liboff’s 90th Birthday. Although I don’t agree with Slesin on much, we both concur that Abe was a “wonderful and generous man.” If you want to hear about cyclotron resonance straight from the horse’s mouth, you can hear Abe talk about his career and work in a series of videos posted on the Seqex YouTube channel. (Seqex is a company that sells products based on Abe’s theories.) Below I link to the most interesting of these videos, in which Abe tells how he conceived of his cyclotron resonance idea.

Abe Liboff discussing the cyclotron resonance theory.
https://www.youtube.com/watch?v=YL-wqJ-PMAQ&list=PLCO-VktC6wofkMeEeZknT9Y4WhMnP76Ee&index=6

Water, Cavendish, and Lavoisier

To understand biological physics, you must know the properties of water. In Intermediate Physics for Medicine and Biology, Russ Hobbie and I discuss water’s density, compressibility, viscosity, heat capacity, surface tension, thermal conductivity, dielectric constant, and index of refraction. It’s behavior is critical for osmosis, diffusion, absorption of x-rays, propagation of ultrasonic waves, and magnetic resonance imaging.

In the very first section of IPMB, about distances and sizes, we say

At the 1-nm scale and below, we reach the world of small molecules and individual atoms. Water is the most common molecule in our body. It consists of two atoms of hydrogen and one of oxygen. The distance between adjacent atoms in water is about 0.1 nm.

Every schoolchild learns that water is H₂O. But how do we know that water is made from hydrogen and oxygen? In other words, how did we first learn that water is not an element itself, but is a compound of two elements?

A Short History of Chemistry,
by Isaac Asimov.

I’ll let Isaac Asimov tell the story. In A Short Histor of Chemistry, he writes

In 1783 [English scientist Henry] Cavendish was … working with his inflammable gas… He burned some of it and studied the consequences. He found that the vapors produced by the burning condensed to form a liquid that, on investigation, proved to be nothing more or less than water.

This was a crucially important experiment. In the first place, it was another hard blow at the Greek theory of the elements [air, water, earth, fire], for it showed that water was not a simple substance but was the sole product of the combination of two gases.

[French chemist Antoine] Lavoisier, hearing of the experiment, named Cavendish’s gas, hydrogen (“water-producer”) and pointed out that hydrogen burned by combining with oxygen and that therefore water was a hydrogen-oxygen combination.

Asimov's Biographical Encyclopedia
of Science and Technology,
by Isaac Asimov.

So now you know. But these two brilliant scientists had tragic fates. You can find the stories in Asimov’s Biographical Encyclopedia of Science and Technology.

Cavendish (1731-1810):

[Cavendish] was excessively shy and absent-minded. He almost never spoke and when he did it was with a sort of stammer… He build a separate entrance to his house so he could come and leave alone… he even literally insisted on dying alone.

The eccentric had one and only one love, and that was scientific research. He spent almost sixty years in exclusive preoccupation with it. It was a pure love, too, for he did not care whether his findings were published, whether he got credit, or anything beyond the fact that he was sating his own curiosity. He wrote no books and published only twenty articles altogether. As a result, much of what he did remained unknown until years after his death…

Lavoisier (1743-1794):

In the same year that [Lavoisier’s] textbook [Elementary Treatise on Chemistry] appeared the French Revolution broke out. By 1792 the radical antimonarchists were in control…. Lavoisier… was guillotined on May 8, 1794, and buried in an unmarked grave. Two months later the radicals were overthrown. His was the most deplorable single casualty of the revolution.

50 Prominent Medical Physicists

Fifty Outstanding Medical Physicists.

In 2014, to mark its 50th anniversary, the International Organization for Medical Physics published a list of 50 medical physicists who have made an outstanding contribution to the advancement of medical physics over the last 50 years. I thought it would be interesting to see how many Russ Hobbie and I mention in Intermediate Physics for Medicine and Biology.

Hardly any. Only 11 of these 50 prominent medical physicists appear in IPMB.

1. Peter R. Almond, of the M. D. Anderson Cancer Center, helped develop cancer treatments using photons, electrons, and neutrons. IPMB cites his paper “Review of Electron Beam Therapy Physics” (Physics in Medicine & Biology, Volume 51, Pages R455–R489, 2006) coauthored with Kenneth Hogstrom. 
2. F. Herbert Attix worked at the Naval Research Laboratory and then the University of Wisconsin. IPMB cites Attix a dozen times, primarily for his landmark textbook Introduction to Radiological Physics and Radiation Dosimetry. 
3. John Cameron was the father of the medical physics PhD program at the University of Wisconsin. IPMB cites his book Physics of the Body. 
4. Aaron Fenster, of the University of Western Ontario, co-founded a microCT company eventually sold to GE Healthcare. Russ and I cite his paper with Paul Carson about the “Evolution of Ultrasound Physics and the Role of Medical Physicists in the AAPM and its Journal in that Evolution” (Medical Physics, Volume 36, Pages 411–428, 2008). 
5. William Hendee, of the Medical College of Wisconsin, coauthored over thirty books. IPMB cites one of them, written with E. Russell Ritenour: Medical Imaging Physics. 
6. Godfrey Hounsfield won a Nobel Prize for developing X-ray computed tomography, a central topic in Chapters 12 and 16 of IPMB. 
7. Willi Kalender, of the University of Erlangen-Nuremberg, introduced volumetric spiral computer tomography. IPMB cites his book Computed Tomography: Fundamentals, System Technology, Image Quality and Applications. 
8. Paul Lauterbur won a Nobel Prize for the invention of magnetic resonance imaging, the main topic of Chapter 18 in IPMB. 
9. Peter Mansfield shared the Nobel Prize with Lauterbur, primarily for his contributions to MRI, including echo-planar imaging. 
10. Colon Orton, of Wayne State University, studied radiotherapy and was active in the American Association of Physicists in Medicine. In IPMB, Russ and I cite three of his “Point/Counterpoint” articles in Medical Physics, for which he served as moderator. 
11. Peter Wells, of Cardiff University, pioneered techniques using ultrasound imaging, the topic of Chapter 13 in IPMB. Russ and I cite his paper “Ultrasound Imaging” (Physics in Medicine and Biology, Volume 51, Pages R83–R98, 2006).

Another eight don’t appear in IPMB but have been mentioned in this blog: Anders Brahme, John Cunningham, Charles Mistretta, Ervin Podgorsak, Madan Rehani, Jean-Claude Rosenwald, Jacob Van Dyk, and Steve Webb. I’m not familiar with the other 31. I guess I don’t know as much as I thought I did. 😮 You can find the entire list here. 

 

Enjoy! 

*************************

As I was posting this article on my blog, it occurred to me that the list of 50 medical physicists came out about ten years ago, and that I ought to update it to 60 outstanding medical physicists in the last 60 years. Here are my additional ten. I tried to honor the spirit of the list by restricting myself to those who worked in the era from 1963 to 2023, but I couldn’t resist going back just a little further to select a few who worked in the 1950s.

1. Paul Callaghan developed microscopic MRI 
2. Hermann Carr proposed using gradients to image with magnetic resonance
   
3. Allan Cormack won the Nobel Prize for his work on computed tomography
   
4. Raymond Damadian performed early work on developing MRI
   
5. Erwin Hahn discovered the nuclear magnetic resonance spin echo
6. Eric Hall is the author of Radiobiology for the Radiologist
7. John Hubbell compiled data on photon cross sections and attenuation coefficients
8. Harold Johns is a coauthor of The Physics of Radiology
9. Faiz Khan is the author of The Physics of Radiation Therapy
   
10. William Oldendorf was a pioneer in computed tomography
    

Felix Savart, Biological Physicist

Bust of Félix Savart
in the Institut de France.
From Wikipedia.

 

 

I’m fascinated by scientists who make the transition from medicine to physics, which is the opposite of my own transition from physics to medicine. One example is Félix Savart. In this blog post, I provide several excerpts from a 1959 article by Victor McKusick and H. Kenneth Wiskind, titled Félix Savart (1791–1841), Physician-Physicist: Early Studies Pertinent to the Understanding of Murmurs (Journal of the History of Medicine and Allied Sciences, Volume 14, Pages 411–423).

Savart was born in Meziere, France on June 30, 1791. His family had a long history of excelling in engineering, but Savart chose a different path.

Savart decided on a medical career and about 1808 entered the hospital in Metz. From 1810 to 1814 he served as a regimental surgeon in Napoleon’s armies… After discharge from the army, he completed his medical training in Strasbourg, where he received his doctor’s degree in October 1816. The title of his doctorate thesis was "Du cirsocele." The mundane topic of varicocele [enlarged veins in the scrotum] must have had little intrinsic appeal for him, and it is perhaps slight wonder he did not stay in medicine.

I can understand how that topic might drive a person away from the medical profession. For whatever reason, Savart spent little time practicing medicine. Instead, he was interested in physics, and particularly in sound.

In 1817 Savart returned to Metz with the intention of establishing a medical practice… He spent his time “more in fitting out a laboratory and building instruments than in seeing sick people and perusing Hippocrates…” It was during this period that he… began to devote himself specifically to the study of acoustics, a subject which engaged his attention almost exclusively for the remainder of his life.

McKusick and Wiskind compare Savart to three other physicians who made the transition to physics: Hermann von Helmholtz, Thomas Young, and Jean Leonard Marie Poiseuille. When Savart was 28, he made a life-changing trip to Paris.

In 1819 Savart went to Paris… to consult Jean-Baptiste Biot (1774–1862) in connection with his study of the acoustics of musical instruments. This was undoubtedly a turning point in Savart’s career. Biot encouraged and aided Savart in many ways and took him into collaboration in a study of electricity.

Savart’s name appears in Intermediate Physics for Medicine and Biology only when paired with Biot for the Biot-Savart Law. Russ Hobbie and I write

8.2.3 The Biot-Savart Law

In situations where the symmetry of the problem does not allow the [magnetic] field to be calculated from Ampere’s law, it is possible to find the field due to a steady current in a closed circuit using the Biot-Savart law.

Ironically, Savart is remembered among physicists for this one investigation into magnetism rather than a lifetime studying acoustics. 

Savart was an excellent experimentalist and instrument builder. He made careful measurements of the frequencies produced by a trapezoid violin, which a French commission found to be as good as the violins of Stradivarius. McKusick and Wiskind describe one of his more significant inventions: the Savart wheel.

About 1830 Savart invented a toothed wheel for determining the number of vibrations in a given musical tone. He attached tongues of pasteboard to the hoop of the wheel and arranged for these to strike a projecting object as the wheel was turned… [With this invention] Savart [determined] the frequency limits of audibility of sounds for the human ear [see Section 13.4 in IPMB]. He set the low and high values at 8 and 24,000 cycles per second, respectively... The values he determined are of the same order of magnitude as the 16 to 16,000 cycles per second one usually hears quoted now.

Savart also has a unit named for him.

The savart is a unit related to the perceptible change in frequency; 300 savarts are approximately equal to one octave. However, this unit has not enjoyed general acceptance and usage.

Another unit for frequency interval, discussed previously in this blog, is the cent. A savart is about 4 cents.

Savart became of member of the French Academie des Sciences in 1827, a position he held “until his untimely death on 16 March 1841 at the age of fifty years.”

Félix Savart is a biological physicist in the mold of Helmholtz, Young, and Poiseuille. He’s just the sort of interdisciplinary scientist that Russ and I had in mind when writing Intermediate Physics for Medicine and Biology.

Bart Hopkin describes the Savart wheel.
https://www.youtube.com/watch?v=yhen0XGyheY

A Trapezoid violin, designed by Félix Savart.
https://www.youtube.com/watch?v=Q3npNDKkqsc

 

Jennifer Cash describes the Biot-Savart law.
https://www.youtube.com/watch?v=1BoIH6Quhiw

The Preface as Poetry

Alexander Pope

I mentioned before in this blog that I’m reading Will and Ariel Durant’s eleven-volume masterpiece The Story of Civilization. Recently, in Volume Nine about The Age of Voltaire, they discussed Alexander Pope, the eighteenth century English poet who, among other things, translated the Iliad into English poetry using iambic pentameter heroic couplets. Thus inspired, I decided to translate the preface of Intermediate Physics for Medicine and Biology from prose to poetry. I’d tell you to “Enjoy!” but I’m not sure that’ll be possible for such doggerel.

In the preface to the third edition, 

Russell Hobbie set out on a mission. 

For the two years before seventy three 

He audited the University

Of Minnesota’s medical courses. 

He found a lack of physics discourses. 

An intermediate physics class would 

For these students be so useful and good. 

This book is the result of when he taught 

Such a course that students needed a lot. 

He hoped that even those physics teachers 

Scared of bio would value its features. 

And doctors would find it a good reference 

With the physics concepts never too dense. 

Because the book was used by those whose tools 

From math were not vast he set down four rules: 

Calculus would be used without regret, 

And reviewed in detail when not seen yet. 

Readers should know the vocabulary 

But it’s told from the start, it’s not scary. 

He did not skip steps in derivations, 

And shunned any weirdo math notations. 

Hobbie added someone to help him write 

The Fourth Edition, and they did not fight. 

They wrote a new chapter, but made sure that 

The new edition did not get too fat. 

They added more than one homework problem, 

And a solution manual for them. 

Chapter One reviews biomechanics, 

Stress and strain, also fluid dynamics. 

Then Two discusses the exponential 

A math function that’s truly essential.

Next Three deals with temperature and heat, 

Biothermodynamics it does treat. 

Diffusion’s the topic of Chapter Four 

A random walk, and drift, and so much more. 

Chapter Five describes flow across membranes, 

And osmosis from ions that it contains. 

Six covers bioelectricity, 

And a model by Hodgkin and Huxley. 

Chapter Seven contains the EKG, 

And defibrillation is really key. 

Chapter Eight deals with all things magnetic, 

Interesting, but not too poetic. 

Nine begins with the model of Donnan, 

Then Nernst-Planck, Debye-Huckel, and so on. 

Chapter Ten has lots of mathematics, 

With feedback and chaos and dynamics. 

Eleven derives Fourier transforms.

Least squares and correlations, it brainstorms. 

Next Twelve analyzes tomography, 

Which allows you to image in 3D!

Chapter Thirteen considers ultrasound, 

A topic that you’ll find really profound. 

Next Chapter Fourteen summarizes light, 

Mix red and green and blue and you get white!

Fifteen considers photons and matter: 

Photoelectric and Compton Scatter. 

Chapter Sixteen is about the x-ray, 

Where the unit for dose is named the gray. 

Seventeen is about technetium, 

Nuclear medicine, and even then some. 

Then Eighteen is not about anything 

But magnetic resonance imaging. 

Biophysics is a subject quite broad, 

Of which we are always completely awed. 

Our book has grown and become large enough, 

To fit molecular stuff would be tough. 

We would like to get any corrections,

Or even hear about your suggestions. 

And last we thank our long-suffering wives, 

We know that this book disrupted their lives.

The Age of Voltaire,
by Will and Ariel Durant.

 The Iliad, translated by Alexander Pope (the heroic couplets start at 2:20).

https://www.youtube.com/watch?v=28RNGOCIzYI

 

The Invisible Rainbow

The Invisible Rainbow,
by Arthur Firstenberg.

Over Christmas break, I read The Invisible Rainbow: A History of Electricity and Life, by Arthur Firstenberg. What can I say about such a book? First, if the conclusions in my own book—Are Electromagnetic Fields Making Me Ill? How Electricity and Magnetism Affect Our Health—are true, then everything Firstenberg writes about in his book is false. We disagree about the health risks posed by electromagnetic fields.

Firstenberg covers a wide range of issues in The Invisible Rainbow and let me begin by admitting that I’m not an expert in all of these subjects. For instance, I don’t know much about infectious diseases, such as influenza, and I’m not particularly knowledgeable about viruses in general. However, the Centers of Disease Control and Prevention gathers input from authorities on these topics and here is what it says about the causes of the flu.

“Most experts believe that flu viruses spread mainly by tiny droplets made when people with flu cough, sneeze, or talk. These droplets can land in the mouths or noses of people who are nearby. Less often, a person might get flu by touching a surface or object that has flu virus on it and then touching their own mouth, nose or possibly their eyes.”

Firstenberg, on the other hand, claims that the flu is an electrical disease not caused by a virus spread from person to person. He writes

In 1889, power line harmonic radiation began. From that year forward the earth’s magnetic field bore the imprint of power line frequencies and their harmonics. In that year, exactly, the natural magnetic activity of the earth began to be suppressed. This has affected all life on earth. The power line age was ushered in by the 1889 pandemic of influenza.

In 1918, the radio era began. It began with the building of hundreds of powerful radio stations at [low] and [very low] frequencies, the frequencies guaranteed to most alter the magnetosphere. The radio era was ushered in by the Spanish influenza pandemic of 1918.

In 1957, the radar era began. It began with the building of hundreds of powerful early warning radar stations that littered the high latitudes of the northern hemisphere, hurling millions of watts of microwave energy skyward. Low-frequency components of these waves rode on magnetic field lines to the southern hemisphere, polluting it as well. The radar era was ushered in by the Asian flu pandemic of 1957.

In 1968, the satellite era began. It began with the launch of dozens of satellites whose broadcast power was relatively weak. But since they were already in the magnetosphere, they had as big an effect on it as the small amount of radiation that managed to enter it from sources on the ground. The satellite era was ushered in by the Hong Kong flu pandemic of 1968.

No mechanism is offered to explain how electromagnetic fields might cause a flu pandemic. No distinction is made between power line frequency (60 Hz) and radio frequency (MHz) radiation, although their physical effects are distinct. No estimation of “dose” (the distribution and magnitude of electric and magnetic field exposure) is provided. No randomized, controlled, double-blind studies are cited. He merely lists anecdotal evidence and coincidences.

Perhaps we could just ignore such dubious claims, except that The Invisible Rainbow is often quoted as evidence supporting the assertion that the Covid pandemic is somehow related to 5G cell phone radiation. Why would anyone get a Covid vaccine if they erroneously believe that the disease is caused by electromagnetic radiation? Such misinformation is dangerous to us all.

Firstenberg describes old studies without critical analysis. For instance, on page 73 he writes

In 1923, Vernon Blackman, an agricultural researcher at Imperial College in England, found in field experiments that electric currents averaging less than one milliampere (one thousandth of an ampere) per acre increased the yields of several types of crops by twenty percent. The current passing through each plant, he calculated, was only about 100 picoamperes.

One hundred picoamperes is 10⁻¹⁰ amperes. We aren’t told what the crops were, but let’s assume they consist of a thin stalk that I’ll estimate has a cross-sectional area of one square centimeter (10⁻⁴ m²). That means the current density would be 10⁻⁶ A/m². Furthermore, let’s assume an electrical conductivity on the order of saline, 1 S/m. The resulting electric field is 10⁻⁶ V/m, or one microvolt per meter. This is far less than the electric field that always surrounds us and is caused by thermal fluctuations. The proposition that one milliamp per acre has such an effect defies credulity.

Previously in this blog I have written about Robert Becker—author of The Body Electric—where I dismiss his assertions that nerve axons are semiconductors and that the myelin surrounding some nerve axons carries steady currents. Firstenberg quotes Becker to support these ideas.

It was the Schwann cells, Becker concluded—the myelin-containing glial cells—and not the neurons they surrounded, that carried the currents that determined growth and healing. And in a much earlier study Becker had already shown that the DC currents that flow along salamander legs, and presumably along the limbs and bodies of all higher animals, are of semiconducting type.

Firstenberg believes cell phones cause many health hazards. On page 176, he writes

[Allan Frey] discovered the blood-brain barrier effect, an alarming damage to the protective shield that keeps bacteria, viruses, and toxic chemicals out of the brain—damage that occurs at levels of radiation that are much lower than what is emitted by cell phones today.

In Are Electromagnetic Fields Making Me Ill? I discuss a recent review by Anne Perrin and collaborators, which considered many articles about electromagnetic fields and the blood-brain barrier, and concluded that the literature provides “no convincing proof of deleterious effects of [radio frequency radiation] on the integrity of the [blood-brain barrier]” (Comptes Rendus Physique, Volume 11, Pages 602–612, 2010).

On Page 255, Firstenberg discusses an epidemiological study that found no relationship between cell phones and cancer.

[A] study, published in the Journal of the National Cancer Institute, was titled “Cellular Telephone Use and Cancer Risks: Update of a Nationwide Danish Cohort.” It claimed to come to its conclusions after an examination of the medical records of over 420,000 Danish cell phone users and non-users over a period of two decades. It was clear to me that something was wrong with the statistics.

Firstenberg claims he could not follow up on his suspicions because the authors would not share their data. Recently Martin Röösli and coworkers performed a meta-analysis of many epidemiological studies (including the Danish one), and concluded that they "do not suggest increased brain or salivary gland tumor risk with [mobile phone] use” (Annual Review of Public Health, Volume 40, Pages 221–238, 2019).

I could go on. Firstenberg believes electromagnetic fields are responsible for diabetes, heart disease, and cancer. His views on the mechanism of hearing are at odds with what most researchers believe. He thinks the “qi” that supposedly underlies acupuncture is electric in nature (similar to Becker’s view).

Readers of Intermediate Physics for Medicine and Biology will find little physics in The Invisible Rainbow. One skill that Russ Hobbie and I stress is the ability to make order-of-magnitude estimations of effects, and I don’t see Firstenberg doing that.

I do have some sympathy for Firstenberg. He’s been plagued by a variety of symptoms that he associates with electromagnetic hypersensitivity. I have no doubt his suffering is real. Yet, the evidence from controlled, double-blind experiments does not support his claim that electromagnetic radiation causes his illness. Rubin et al. reviewed many experiments and concluded that “at present, there is no reliable evidence to suggest that people with [idiopathic environmental intolerance attributed to electromagnetic fields] experience unusual physiological reactions as a result of exposure to [electromagnetic fields]. This supports suggestions that [electromagnetic fields are] not the main cause of their ill health” (Bioelectromagnetics, Volume 32, Pages 593–609, 2011). The World Health Organization concludes

EHS [electromagnetic hypersensitivity] is characterized by a variety of non-specific symptoms that differ from individual to individual. The symptoms are certainly real and can vary widely in their severity. Whatever its cause, EHS can be a disabling problem for the affected individual. EHS has no clear diagnostic criteria and there is no scientific basis to link EHS symptoms to EMF [electromagnetic field] exposure. Further, EHS is not a medical diagnosis, nor is it clear that it represents a single medical problem.

I put Arthur Firstenberg in the same category as Martin Pall, Robert Becker, Paul Brodeur, and Devra Davis: well-meaning scientific mavericks whose hypotheses have not been confirmed. The Invisible Rainbow is an interesting read, but beware: as science it is flawed.

 Listen to Arthur Firstenberg, author of The Invisible Rainbow, answer questions about the hidden dangers of wireless and cellular phone radiation (I post this video so you can hear his side of the story, not because I agree with him).

https://www.youtube.com/watch?v=jyfa454Akm0

Happy Birthday, Robert Resnick

Physics,
by Halliday and Resnick.

Robert Resnick, physics textbook author extraordinaire, was born 100 years ago last Wednesday (January 11, 1923). A Rensselaer Polytechnic Institute website states

Robert Resnick is professor emeritus at Rensselaer and the former Edward P. Hamilton Distinguished Professor of Science Education, 1974–93. Together with his co-author David Halliday, he revolutionized physics education with their now famous textbook on general physics, still one of the most highly regarded texts in the field today.  

He is author or co-author of seven physics textbooks, which appear in 15 editions and more than 47 languages. 

Resnick introduced Rensselaer’s interdisciplinary science curriculum in 1973 and was its chair for 15 years. He was awarded the American Association of Physics Teachers’ highest honor, the Oersted Medal, in 1975, and served as its president, 1986–90. A Distinguished Service Citation issued in 1967 by the association said, “Few physicists have had greater or more direct influence on undergraduate physics students than has Robert Resnick.” 

Rensselaer named its Robert Resnick Center for Physics Education in his honor. 

Quantum Physics of Atoms, Molecules,
Solids, Nuclei, and Particles,
by Eisberg and Resnick.

In Intermediate Physics for Medicine and Biology, Russ Hobbie and I cite Resnick’s famous introductory physics book with Halliday once, but we cite his modern physics textbook—Quantum Physics of Atoms, Molecules, Solids, Nuclei, and Particles—with Robert Eisberg many times. In fact, in IPMB we reproduce (with permission) five of Eisberg and Resnick’s figures. I remember studying from their textbook as an undergraduate physics major at the University of Kansas.

Resnick died nine years ago (January 29, 2014). To learn more about his remarkable life, you can read his obituary in Physics Today. 

Happy 100th birthday, Robert Resnick. We miss ya.

An excerpt from Robert Resnick’s Oersted Medal Lecture.

https://www.youtube.com/watch?v=THPGQDLdeHw&t=16s