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[1208] SZILARD ZWICKY [1209]
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[1208] SZILARD
ZWICKY [1209] In 1963 he became head of the physics department at the Imperial College of Science and Technology and in 1965 he was elected president of the Royal Soci ety. In 1969 he was made a life peer and became Lord Blackett. [1208] SZILARD, Leo (zeefiahrd) Hungarian-American physicist
ary 11, 1898 Died: La Jolla, California, May 30, 1964 Szilard, the son of a Jewish engineer, obtained his doctorate at the University of Berlin in 1922 and joined its faculty thereafter. When Hitler came to power, however, Szilard, mindful of his Jewish origins, lost no time in leaving Germany, and went to England. While in England he went into the field of nuclear physics and in 1934 con ceived the idea of a nuclear chain reac tion, in which a neutron induced an atomic breakdown, releasing two neu trons, which break down two more atoms, and so on. He even applied for a patent for the process, keeping it secret, in part, because he foresaw its impor tance in nuclear bombs. However, the reaction he had in mind involved the breakdown of beryllium to helium and this did not, in fact, form a practical chain reaction. Nevertheless, when uranium fission was discovered by Hahn [1063] and an nounced by Meitner [1060] in 1939, Szilard saw that here was a chain reac tion that would be practical. He had gone to the United States in 1937 and now he realized the importance of get ting a practical nuclear bomb before Hitler did. The newspapers had publi cized the early fission experiments with out really knowing what they were talk ing about and Szilard’s blood ran cold. He persuaded America’s physicists not to publish their work in the field to avoid giving the Germans any ideas. That summer he, Wigner [1260], and Teller [1332] (all Hungarian refugees) persuaded Einstein [1064] to send his fa mous letter (written by Szilard, actually) to President Franklin D. Roosevelt, and this set in motion the Manhattan Project that was to prepare the first nuclear bomb.
Szilard worked with Fermi [1243] in Chicago on the development of the first self-sustained nuclear reactor, their inno vation being the use of graphite as a moderator to slow neutrons to a velocity where they were most efficiently cap tured. (The French, under Frédéric Jo- liot-Curie [1227], were trying to use heavy water for the purpose.) In 1943 Szilard became an American citizen. Once the atomic bomb was ready for use, Szilard was one of the large group of scientists who, in revulsion at their own work, pleaded that the bomb not be used or else used only over unin habited territory as a demonstration. The military, and some scientists such as Compton [1159], thought otherwise, however, and President Harry S Tru man made the fateful decision that vis ited nuclear destruction upon the Japa nese cities of Hiroshima and Nagasaki. Szilard veered away from nuclear physics after the war, accepting a post as professor of biophysics at the University of Chicago in 1946. He labored unceas ingly to ban nuclear warfare and even nuclear testing and to turn nuclear power to peaceful uses only. In 1959 he received the Atoms for Peace award. [1209] ZWICKY, Fritz (tsvik'ee) Swiss astronomer Born: Varna, Bulgaria (of Swiss parents), February 14, 1898 Died: Pasadena, California, Feb ruary 8, 1974 Zwicky studied at the Federal Institute of Technology in Zürich, Switzerland, obtaining his doctorate in 1922. He went to the United States in 1925 and taught at the California Institute of Technology and worked at the Mount Wilson and Palomar observatories. One of Zwicky’s fields of interest was supernovas. The distinction between these and ordinary novas was first ad vanced by him and Baade [1163] in 1934.
Ordinary novas had been observed in 761 [1210] ASTBURY
SCHOENHEIMER [1211]
plenty by astronomers, but in 1885 a nova had been observed in the Androm eda galaxy (or nebula, as it was then called) which attained the magnitude of 7, so that it was nearly visible to the naked eye. In the 1920s, when the dis tance of the Andromeda galaxy was set at 800,000 light-years by Hubble [1136], it was realized that the nova must have been as bright as many millions of ordi nary stars to appear so luminous at such a distance. A supernova, then, is a star that blew up in one grand flash, whereas an ordinary nova merely puffs away per haps one percent of its mass and then re turns to its ordinary way of stellar life. The extremely bright novas observed by Tycho Brahe [156] and Kepler [169] must have been supernovas within our own galaxy as was the nova of 1054, which ended as Rosse’s [513] Crab neb ula.
Since Kepler’s time, however, no su pernova had appeared in our galaxy and Zwicky searched the outer galaxies for any that might be bright enough for spectral studies. His researches showed that in any given galaxy, only two or three supernovas appear every thousand years. The connection of supernovas and white dwarfs has been illuminated by Chandrasekhar [1356]. Zwicky also investigated clusters of galaxies. In 1942 he studied the large cluster of galaxies in the constellation Coma Berenices and showed that their distribution resembled statistically the distribution of molecules in a gas at tem perature equilibrium. Thus, the largest and the smallest seem to join hands. [1210] ASTBURY, William Thomas English physical biochemist Born: Stoke-on-Trent, Staffordshire, February 25, 1898 Died: Leeds, Yorkshire, June 4, 1961
Astbury did his research at Cambridge under William Henry Bragg [922] from 1921. In 1928 he joined the faculty of the University of Leeds. In 1930 he was studying the structure of wool and subjected it to X-ray diffrac tion determinations (the work that had made Bragg famous) both in the stretched and unstretched form. The X-ray diffraction pattern changed and with that Astbury began to try to work out the structure of protein molecules generally from such studies. In 1937 he made the first X-ray diffraction studies of nucleic acid. Astbury’s determinations of structure were wrong, but they were a respectable first attempt and they led on to the work of Pauling [1236] in proteins and James Dewey Watson [1480] and Crick [1406] in nucleic acids. [1211] SCHOENHEIMER, Rudolf (shem'high-mer) German-American biochemist Born: Berlin, May 10, 1898 Died: New York, New York, September 11, 1941 Educated in Germany and receiving his Ph.D. at the University of Berlin, in 1923, Schoenheimer was another of those German-Jewish scientists to whom the coming of Hitler meant that safety lay only in exile. He emigrated to the United States in 1933 and obtained a po sition at Columbia University’s College of Physicians and Surgeons. In 1935 Schoenheimer introduced the use of isotopic tracers in biochemical research. Hevesy [1100] had been the first to make use of isotopes more than a decade earlier, to be sure, but he had worked with lead isotopes, atoms of types that were foreign to living tissue, and isotope work had languished since. By 1935, however, deuterium, the heavy isotope of hydrogen, had become avail able in reasonable quantity, thanks to the work of Lewis [1037] and Urey [1164]. Here was an isotope of an ele ment naturally found in living tissue. Schoenheimer made use of fat mole cules that contained deuterium atoms in place of some of the hydrogen atoms. These were incorporated into the diet of laboratory animals, whose tissues treated the deuterized fat much as they would ordinary fat. Analysis of the body fat of the animals for deuterium content threw 7 6 2
[1212] RABI
FLOREY [1213] new and startling light on hitherto ob scured facets of biochemistry. It was believed at the time, for in stance, that the fat stores of an organism were usually immobile; that the mole cules composing it just lay there, so to speak, until such time as famine de manded their use. In times of reasonable nourishment, it was thought, the body made use of newly digested fat pouring in from the alimentary tract. However, when Schoenheimer fed rats on his deuterized fat and analyzed the fat stores, he found that at the end of four days the tissue fat contained nearly half of the deuterium that had been fed the animal. In other words, ingested fat was stored and stored fat was used. There was a rapid turnover and the body constituents were not static, but changed constantly and dynamically. Schoenheimer then made use of a heavy isotope of nitrogen, soon after it was first prepared in quantity by Urey, and tagged amino acids with it. In a series of experiments he traced the heavy nitrogen within the amino acids of the organism after it had been ingested as part of a single amino acid. He found that here, too, there was constant action. Molecules were rapidly changing and shifting, even though the overall move ment might be small. Schoenheimer’s work was the first to catch body chemistry in action, so to speak, and he was undoubtedly the fa ther of isotopic tracer research in bio chemistry. However, in 1941, during the darkest days of World War II, Schoen heimer committed suicide. He did not live to see the defeat of Germany, nor the coming, in quantity, of radioactive isotopes after World War II; isotopes which, in the hands of men like Calvin [1361], were to serve as a still more delicate tool for revealing the de tails of chemical mechanisms within liv ing tissue. [1212] RABI, Isidor Isaac (rah'bee) Austrian-American physicist
in Poland), July 29, 1898 Rabi was taken to the United States at the age of one. He did his undergraduate work at Cornell University on a scholar ship, majoring in chemistry, and gradu ated in 1919. After a few fruitless years as a chemist, he decided it was physics he really enjoyed. He returned to school and obtained his Ph.D. at Columbia Uni versity in 1927. From 1927 to 1929 he made the European rounds, studying with a number of prominent physicists, including Bohr [1101], Sommerfeld [976], Pauli [1228], Heisenberg [1245], and Stem [1124]. Stem’s work particularly impressed him. When Rabi returned to the United States he obtained a faculty position at Columbia University in 1929 and began work on molecular beams on his own. In 1933 and thereafter he instituted im provements in the study of molecular beams that made it possible to measure magnetic properties of atoms and mole cules with great accuracy. This finding was important in connection with the de velopment of the maser (acronym for “microwave amplification by stimulated emission radiation”) by Townes [1400], As an analytic technique, it was to be outdone by the nuclear magnetic reso nance of Purcell [1378], In 1944, the year after Stern’s Nobel Prize, Rabi himself won the Nobel Prize in physics. During World War II, Rabi worked on radar and on the atomic bomb and after the war served as chairman of the ad visory committee to the Atomic Energy Commission from 1952 to 1956. In 1964 he became the first University Professor —without departmental ties—in Colum bia’s history. [1213] FLOREY, Howard Walter Florey, Baron
Australian-English pathologist Born: Adelaide, Australia, Sep tember 24, 1898 Died: Oxford, England, February 21, 1968 Florey attended the University of Ad elaide and obtained his medical degree there in 1921. He then traveled to En
[1213] FLOREY
LYSENKO [1214] gland as a Rhodes Scholar, studying at Oxford (under Sherrington [881]) and Cambridge. He received a Ph.D. at Cambridge in 1927. He went on to teach pathology, first at the University of Sheffield in 1931 and then, beginning in 1935, at Oxford. Domagk’s [1183] discovery in the mid- 1930s of the antibacterial activity of Prontosil had raised the issue of che motherapy with new urgency. Dubos’ [1235] isolation of the first antibiotic in 1939 stimulated matters even further and the coming of World War II gave the fight against infection important mili tary incentives. Florey had been working on lyso zyme, an antibacterial agent discovered by Fleming [1077], and that led natu rally to a consideration of Fleming’s ne glected work on penicillin. In collabo ration with Chain [1306], Florey set about trying to isolate the actual antibac terial agent from the mold studied by Fleming. Rather quickly he obtained a yellow powder from moldy broth that contained the agent. During World War II, an intense course of research in Great Britain and the United States succeeded in preparing ever purer samples of penicillin. Initial studies of antibacterial activity were made with preparations containing only 1 percent of penicillin. Even so, these were encouraging. In 1941 penicillin was used on nine cases of human bac terial infection with dramatically success ful results. Penicillin was first used for war casu alties in Tunisia and Sicily in 1943, and very successfully, too. By 1945 prepara tions were prepared in a concentration sufficient to display antibacterial activity even after a fifty-millionfold dilution and half a ton per month was being pre pared. Under war pressure, the chemical structure of penicillin was worked out by means of X-ray diffraction studies. The X rays were scattered in complicated fashion indeed from so complex a mole cule, and for the first time electronic computers were used to work out the te dious mathematics involved; this fore shadowed the even greater computer vic tories in this field a decade later in con nection with Hodgkin [1352] and her de termination of the structure of vitamin B i 2. With the problem of structure beaten, methods of quantity production were de vised. After the war, penicillin became an important medical workhorse, and it is still the most used of the antibiotics. Unlike some of the antibiotics discovered subsequently, penicillin has a very low toxicity. Florey was knighted in 1944 for his work, and in 1945 he shared the Nobel Prize in medicine and physiology with Fleming and Chain. In 1958 synthetic penicillin analogues were formed by let ting the mold form the basic ring struc ture and then adding different groups to that structure in the test tube. Such synthetic penicillins could be used against bacteria unaffected by the natural product.
In 1960 Florey was elected president of the Royal Society and in 1962 provost of Queen’s College, Oxford. In 1965 he was given a life peerage and became Baron Florey of Adelaide. [1214] LYSENKO, Trofim Denisovich (lee-syenTco) Soviet biologist Born: Karlovka, Poltava Oblast, Ukraine, September 29, 1898 Died: Kiev, Ukraine, November 20, 1976 Lysenko graduated from the Poltava School of Horticulture in 1921 and from the Kiev Institute of Agriculture in 1925.
After 1928 Lysenko was concerned with the cultivation of new varieties of plant forms, as Burbank [799] was a half century earlier. Like Burbank (but with far less cause, considering the half-cen tury advance in genetic knowledge), Ly senko maintained that acquired charac teristics could be inherited. He believed for instance that he could alter the ge netic constitution of strains of wheat by properly controlling the environment. He denounced violently those geneticists, no tably Mendel [638], Weismann [704],
[1215] ZIEGLER
MÜLLER [1216] and T. H. Morgan [957], who had main tained that inherited characteristics were inborn and not affected by environ mental change. Lysenko was adroit enough to so ar range his arguments as to make them seem to fit Soviet economic and philo sophic theories. (Even if they did, of course, that would in no way affect their scientific truth or falsity.) The Soviet leader Joseph Stalin, increasingly arbi trary in his old age, was foolish enough to think that he could profitably take a hand in scientific disputes. At a gather ing of agricultural scientists, Lysenko’s views, with the powerful support of Stalin, were accepted, and geneticists who disagreed, notably Vavilov [1122], were forced to disagree in silence. With Stalin’s death in 1953, Lysen ko’s views, essentially worthless, receded somewhat into the background. Never theless, serious damage had been done to Soviet biology and to the world image of Soviet science that was not repaired until the launching of Sputnik I in 1957. Then for a time Soviet science came to be overestimated as seriously, perhaps, as it had earlier been underestimated. Lysenko retained some influence dur ing the period of dominance of Nikita Khrushchev, but with the latter’s fall in 1964 the end seemed to come. In 1965 Lysenko was removed from his post as director of the Institute of Genetics, which he had headed since 1940, and was roundly attacked by other scientists. It was an interesting way to celebrate the centennial of Mendel’s publication of his genetic laws. [1215] ZIEGLER, Karl (tsee'gler) German chemist
Nassau, November 26, 1898 Died: Muhlheim-Ruhr, August 12, 1973
Ziegler, the son of a minister, obtained his Ph.D. at the University of Marburg in 1920 and then taught first at Frank furt and then at Heidelberg. He was early interested in metallic-or ganic compounds, searching for improve ments on the famous compounds devel oped by Grignard [993]. Unexpectedly, these metallic-organic compounds proved of importance in the synthesis of poly mers. Throughout the 1930s and 1940s, plastics had been manufactured out of polymers that were produced in rather hit-or-miss fashion. That is, mole cules were put together in such a way as to produce random orientation. Polyeth ylene, for instance, was formed by put ting the two-carbon compound, ethylene, into long chains, end to end. But branches would form in the chain, weak ening the final product and giving it a low melting point. In 1953 Ziegler discovered that he could use a resin, to which ions of metals such as aluminum or titanium were attached, as a catalyst in the pro duction of polyethylene. Chains without branching were then formed. As a result, the new polyethylene was tougher than the old and melted at a considerably higher temperature. Similar catalysts are now being used, thanks to the work of Natta [1263], to orient molecules into long chains in which small side-chains of carbon atoms all point the same way—instead of in different directions at random—with the result that plastics and other polymers with new and useful properties can now be designed. As a result, Ziegler and Natta shared the 1963 Nobel Prize in chemistry. [1216] MULLER, Paul Hermann (myoo'ler) Swiss chemist
January 12, 1899 Died: Basel, October 13, 1965 Muller, the son of a civil servant, was a practicing chemist by the time he re turned to school for his degrees. He was educated at the University of Basel, ob taining his doctorate in 1925. He ac cepted a position thereafter with a dye firm.
In 1935 he began a research program designed to discover an organic com pound that would kill insects quickly,
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