|
02/28/2011
Numbers - Planets, Microbes, Courtship and Phone
CHAPTER 7 - WINDING DOWN AT PITT
Longtime readers will know that, given my obsession with outer space, I am compelled to start off with NASA's announcement (11-030) on February 2 that the space telescope Kepler has found 1,235 "planet candidates" outside our solar system. If most of these candidates do prove to be planets it will roughly triple the number of known planets orbiting stars other than our own Sun. Out of these planet candidates, 68 are "near-Earth" size and five of these are in habitable zones. Could one of these be the Holy Grail that harbors some form of life? The NASA press release indicates that Kepler used the dimming of a star's light as a planet transits across the face of the star to detect the planet candidates. Heretofore, most of these "exoplanets" have been discovered by the "wobble" in a star's position caused by the pull of the planet's gravity on the star. In order to confirm that one of these candidates is indeed a planet, NASA likes to get three cases of dimming of the star's light. Since the planets in the habitable zones typically take about a year to orbit their stars, it will take about another three years to spot three transits.
When I first started writing these columns back in 1999, finding a planet orbiting another star was a big deal. Now Kepler is finding a plethora of planets. On a completely different scale, decoding the human DNA was an equally big deal, perhaps even bigger. There was briefly a feeling that, with DNA decoded, everything would quickly fall into place and the mysteries of life and diseases would soon be unraveled. However, it was soon determined that all that "junk" DNA was not junk but played an important role in how the genes operated. Not only that, but how the DNA is folded up and where it is located in a cell also play very important roles in the chemistry that goes on within our cells. Recently, I've seen more and more articles on the fact that we humans harbor huge numbers of microbes including bacteria, viruses and fungi that comprise what scientists are calling our microbiome.
I was especially taken with an article, "The Ecosystem Inside", by Michael Tennesen in the March issue of Discover magazine. It seems that we adult humans have in us and on us as many as 200 trillion microbes, some 20 times as many cells as we have in our bodies. The article likens the diverse collection of microbes in our gut to an ecosystem akin to a lush rain forest. What really struck me was a statement in a sidebar to the article by Amy Barth putting the weight of the menagerie of microbes in our gut at as much as four pounds! It's a fascinating article that puts into perspective the balance between 'good" and "bad" microbes and how antibiotics can upset that balance. Scientists are now trying to determine the nature of the thousands of different organisms in the microbiome and perhaps figure out some cures for diseases by altering or bringing it back into balance.
All these big numbers of cells and planets can get overwhelming at times. Let's get back to my memoirs and we'll see that courtship and numbers may not be compatible. Last month (see archives if you missed it) I told how I danced my way into a romance with Vicki, my wife to be. This month I'll tell of how this romance led to the most serious mistake of my scientific career. This may be familiar to longtime readers but I'll repeat it here for completeness. To set the stage, let's look at my PhD project. I previously mentioned that my professor, Ed Wallace, gave me the opportunity to drop my Master's project (and my passion for radioactivity) and work on a PhD project supported by the Office of Naval Research. In essence, the project involved measuring the electromotive force (emf) of electrochemical cells with one electrode being pure magnesium and the other electrode being an alloy of magnesium and cadmium. (The emf is akin to the voltage of a cell battery.) I won't go into detail but, by measuring cells with alloys of different compositions of magnesium and cadmium at different temperatures, I could calculate the values of certain thermodynamic properties of the alloy system. For example, one such property is the heat of reaction, that is, the heat evolved when magnesium and cadmium react to form an alloy of a given composition.
Because the cells were measured at elevated temperatures (270 -300 degrees Centigrade), I had to use an electrolyte of fused salts (lithium, rubidium and magnesium bromides). The research involved a few challenges. Lithium bromide is hygroscopic, i.e., it likes to soak up water from the atmosphere and I had to take precautions to keep it dry. Cadmium metal has a significant vapor pressure at around 300 degrees Centigrade. I made the magnesium-cadmium alloys by melting them in a closed system involving a little pot with a lid and, using magnets, could carry out the melting and pouring of the alloy into a mold in what I thought was a somewhat clever setup. When I started making the cells to measure the voltages, I expected to follow the usual procedure of making a cell with an anode (magnesium) and a cathode (the alloy).
However, I had the brilliant idea (I thought it was clever at the time) of making a cell with seven electrodes, with 3 or 4 magnesium electrodes and/or 3 or 4 different alloys. This meant I could finish my thesis work in a considerably shorter time than by making and measuring individual cells with just two electrodes. I soon found that maybe I was wrong. In those days the voltage measurements were made by using a potentiometer. This is an instrument where you measurement the emf by essentially dialing in a voltage to counter the voltage of your cell, using a sensitive galvanometer to indicate any differences in voltage. When the galvanometer needle or indicator does not swing one way or the other, you've found the proper emf . Well, in my cells with multiple electrodes, I at first connected the lead wire from one of my magnesium electrodes directly to one post of the potentiometer and used a rotating switching device to rotate the leads from the other electrodes into connection with the other post on the galvanometer. The data were jumping all over the place! I would get a different voltage on the same electrode pair when I switched back and forth. It looked like my brilliant idea of multiple electrodes was not so bright after all.
However, I decided to disconnect my one magnesium electrode and only connect it in sync with whatever other electrode I was trying to measure. It worked beautifully . There apparently was some sort of electrical "pickup" or stray voltage that came into play when I kept the one electrode hooked up permanently! Within weeks I finished taking data. All that remained was for me to calculate all my data and write my thesis.
Here's where courtship and mathematics proved a poor combination! One of the calculations involved something known as the Gibbs-Duhem equation. If you asked me to write the equation today, I would have to look it up in a textbook. However, I do know that making the calculations involved something known as graphical integration. Today, I'm sure I could do the calculations using a computer program but there weren't computers back in 1950. The graphical integration involved essentially plotting a graph of x versus y. The graph looked somewhat like a ski jump, starting up high in y and tailing off down low as x increased. The calculation involved measuring the areas under the curve for different intervals of x. You can do this by counting the squares on your graph paper or even cutting up the sections of graph paper and weighing them. To check whether I knew how to do graphical integration, I took a paper from the literature on another alloy system and checked to see if I came out with the same results as the authors of that paper. I did.
I was ready to do my graphical calculations on my magnesium cadmium data. In order to make very precise calculations, I took an extra large piece of graph paper and tacked it down on a drafting table. That evening I was ready to plot my data and start counting squares. In last month's column, I mentioned that Vicki was taking a Spanish class in a local high school and that I would walk her back to the nurses dorm after class. It was time to go over to the high school and on the way back I thought, hey, she can help me with my graphical calculations. So, we stopped at Alumni Hall and I asked her to read me the numbers, which I plotted on my large graph paper. It didn't take very long and I walked her back to the dorm.
When I got back to my calculations the next day, all looked in order; there was the ski jump. I made my calculations fairly expeditiously and wrote my thesis. All that remained was to defend the thesis. The only problem I had in my thesis defense was with Dr. Alexander Silverman, then chairman of the chemistry department at Pitt. To analyze my alloys, I reacted the alloys to form sulfates. Silverman looked at my calculations and it he must have spent about 15 minutes criticizing me for using an "old" value of the atomic weight of sulfur in my calculations. Apparently, someone had come up with a more recent value that differed from the one I found in a chemistry handbook. It didn't make a whit of difference in the calculations. Nobody else on my committee had any criticisms and I had my PhD in 1950.
Now, as radio broadcaster Paul Harvey would say, for the rest of the story. After I left Pitt, Ed Wallace had one of his graduate students check my calculations and he confirmed my results. The paper was published in the Journal of Physical Chemistry in 1952. As we'll see next month, I was off to NACA and then, in 1952 joined Bell Labs. After I'd been at Bell Labs for a while I gave a seminar on my thesis. It wasn't too long after that talk that I got a chilling letter from Ed Wallace saying that some fellow in Australia had read our paper and wrote Wallace that he was confused by the calculations. It took me a few seconds at most to realize with horror what had happened. I won't say it was my wife's fault but my calculations were based on a graph on which the values of x and y were interchanged - I had not a plot of x vs. y, but y vs. x! And Dr. Silverman was concerned about the atomic weight of sulfur! The graduate student obviously did not make an independent plot of my data but just took my graph and re-measured the areas.
As I said, I can't say definitely that my wife mixed up x and y when she read the data to me. However, it has become clear to me over the 60 years we've been married that numbers are not her forte. She can say hundreds when she means thousands, or vice versa, and it is not out of the question that she could have been equally unconcerned about x and y!
Well, so much for numbers. But wait, something happened last week concerning numbers that makes me wonder about the Internet. Over the past year or so my wife reestablished contact with a childhood friend, Betty, who still lives in the area in Pennsylvania where Vicki was born and raised. Last week, Vicki called Betty several times and each time she got a weird sound, something like what you get with a fax machine. Vicki finally called an operator, who said the phone was "discontinued", prompting concern that Betty might have had some sort of medical problem. Vicki remembered that Betty had a daughter named Colleen. I entered Colleen's name on one of the phone number-search sites on the Internet and, sure enough, her name came up with a phone number and an address on the street where Betty lives.
Vicki called the number and a lady answered. Vicki, thinking she was talking to Colleen, said she was an old friend of Betty's and was concerned about her. The lady said that indeed Betty was in the hospital and had had surgery. Vicki then told the lady that her maiden name was Vicki Novak and the lady shouted, "Vicki Novak!! I'm Sarah P.!!!" Turns out that Vicki knew Sarah from her childhood and they spent a long time reminiscing about old times. What bugs me is that the number was not Colleen's number and she does not live at that address. So how did I come up with Sarah P.? To make matters more perplexing, Vicki then called the hospital asking to talk to patient Betty Y. The gal at the hospital told Vicki that there was no patient Betty Y. there! So Vicki called another (correct) number I found for one of Betty's sons. He gave her a phone number in the hospital that Vicki used to talk directly to Betty, who indeed was still a patient.
OK, maybe you're thinking, as I was, that Betty probably had a cell phone with her and that was possibly why the hospital didn't seem to know she was a patient. However, my wife used that same number to call again a few days later and got a patient in the same room. The fellow said Betty had been transferred to a nursing home. Obviously, the hospital has a problem! And it's the hospital where Vicki got her R.N.
Well, I've rambled on enough about numbers. Next column, hopefully, will be posted on April 1 or thereabouts. I'll finish my days at Pitt and make my way to Cleveland.
Allen F. Bortrum
|
