Sunday, November 27, 2011
Sherrington was a good student and earned the highest marks in his class in botany, human anatomy and physiology. He earned membership in the Royal College of Surgeons in 1884 and earned a first class in the Natural Science Tripos and earned a M.B. Bachelor of Medicine and Surgery in 1885. In 1886 he earned the title of Licentiate of the Royal Collage of Physicians. During the winter of 1884-5 he worked for German physiologist Friedrich Goltz in Strasbourg, Germany. In 1885 he served as part of a committee that went to Toledo, Spain to investigate a potential vaccine for cholera. The vaccine turned out to be ineffective. Later that year he went to Berlin to work for Rudolf Virchow, studying the cholera specimens gathered in Spain. Virchow sent Sherrington to Robert Koch for a class on technique. Sherrington stayed with Koch for a year and studied bacteriology. In 1886 Sherrington went to Italy to investigate a cholera epidemic.
In 1887 Sherrington was elected as a fellow at Caius College and appointed lecturer in systematic physiology at St. Thomas Hospital Medical School. In 1891 Sherrington was appointed superintendent of the Brown Institute for Physiological and Pathological Research at the University of London. Sherrington's research topics included leukocytes, the specific gravity of blood, the presence of bacteria in secretions and changes in blood in local inflammation. He was also able to cure his nephew from diphtheria by injecting him with anti-toxin. This is the first recorded case of the successful use of anti-toxin in diphtheria treatment in England. He also researched spinal reflexes, which laid the basis of the work for which he is most remembered. In 1895 he was appointed as the Holt Professor in physiology at Liverpool University. He continued his research into spinal cord innervation and the innervation of opposing muscles.
In 1906 Sherrington published The Integrative Action of The Nervous System, a book so important in neurophysiology that its influence has been compared to Newton's Principia's importance to physics. In the book he introduced the term synapse to describe the space between nerve cells. Nerve cells function to carry action potentials, a wave of electrochemical energy, that move down nerve cells. Synapses, the spaces in between nerve cells, carry the impulse from one cell to the next by means of a chemical neurotransmitter. When the action potential reaches the end of one nerve cell (called dendrites) that cell releases a neurotransmitter that signals the next cell to fire an action potential. The neurotransmitter diffuses across the synapse and is detected by receptors on the second nerve cell. In response to the neurotransmitter being detected by the receptor the second nerve cell fires, sending an action potential down the nerve. For his work in elucidating the structure and function of the nervous system Sherrington shared part of the 1932 Nobel Prize for physiology and medicine.
In 1913 he was offered the Waynflete chair in physiology, where he remained until his retirement 1936. During World War I, when his classes were reduced he worked at a shell factory and studied fatigue, particularly industrial fatigue. Other honors won by Sherrington include election to the Royal Society in 1893 and he served as its president in the early 1920s. He won the Royal Medal from the Royal Society in 1905, the Knight of the Grand Cross in the Most Excellent Order of the British Empire in 1922 and Order of Merit in 1924.
He spent his retirement in a house he built in his boyhood home, Ipswitch, keeping an active correspondence with many of his former students. He died on March 4, 1952
O'Connor, W.J.; British Physiologists 1885-1914: A Biographical Dictionary; Manchester University Press ND; 1991
Pearce, J.M.S.; "Sir Charles Scott Sherrington and the Synapse"; Journal of Neurology, Neurosurgery, and Psychiatry(2004)75:544
Charles Scott Sherrington Wikipedia Entry
Sir Charles Scott Sherrington Nobel Biography
Sunday, November 20, 2011
After finishing his bachelors Hubble went to England, where he studied law, at the insistence of his dying father, at Queens College, Oxford on a Rhodes Scholarship. He remained in England for three years. Upon returning to the United States Hubble taught high school mathematics, physics and Spanish, also coaching basketball, for a year. After a year teaching he returned to his passion, astronomy, and began studying at the Yerkes Observatory at the University of Chicago, finishing his Ph.D. in 1917. His dissertation was titled "Photographic Investigations of Faint Nebulae" Hubble served in the United States Army during World War I, rising to the rank of major. In 1919 Hubble accepted a position at the Mt. Wilson Observatory, in Pasadena, California, where he remained on staff until his death. During World War II Hubble worked for the Army at the Aberdeen Proving Ground, in Aberdeen, Maryland, where he worked on ballistics and for which he was awarded the Legion of Merit.
Hubble's arrival at the Mt. Wilson Observatory coincided with the instillation of the Hooker Telescope, a 2.5 meter telescope, which at the time was the largest in the world. At the time most astronomers believed that the Milky Way Galaxy was the extent of the universe and that the fuzzy objects called nebulae were contained within it. Using the Hooker Telescope, Hubble was able to show that some of these fuzzy objects contained stars and were much too distant to be inside of the Milky Way. Hubble showed that some of these objects were in fact galaxies and he devised a method of categorizing them based on their shape, called the Hubble Sequence, which is still used today classify galaxies. Hubble's most astonishing discovery came from studying the spectra of 46 galaxies in which he showed that the further galaxies were from each other the faster that they were moving away from each other. Based on this observation Hubble concluded that the universe was expanding at a constant rate (it later was determined that the rate of expansion is actually increasing). With his colleague Milton Humason, he estimated that the rate of expansion is 500 Km per second per megaparsec. So a galaxy one megaparsec away is receding from the Milky Way at a rate of 500Km/second (a mega parsec is one million parsecs, each 3.3 light years or about 3.08x1022meters). This is called the Hubble Constant and astronomers have been refining the measurement ever since.
Honors won by Hubble include the Bruce Medal, awarded by the Astronomical Society of the Pacific, the Franklin Medal, awarded by the Franklin Institute, and Gold Medal, the highest honor of the Royal Astronomical Society of Great Britain. He was never awarded the Nobel Prize because it was not till after his death that astronomy was considered a subject for which the Nobel Prize in physics could be awarded and the Nobel Prize is not awarded posthumously. In addition to the Hubble Space Telescope, a telescope orbiting the earth, an asteroid and a crater on the moon are also named after Hubble. In 2008 the United States Postal Service issued a stamp honoring Hubble.
Hubble died on September 23, 1953.
Christianson, Gale E.; Edwin Hubble: Mariner of the Nebulae; University of Chicago Press; 1996
Anonymous; Edwin Hubble Biography at edwinhubble.com
Anonymous: Edwin P. Hubble at Hubble Space Telescope Website (hubble.nasa.gov)
Edwin Hubble Wikipedia Entry
Sunday, November 13, 2011
With Edgar Allen, his research assistant, Doisy investigated the mouse estrous cycle and by 1936 they succeed in isolating all three estrogens (esterone, esterdiol and estratiol) from human urine (while collecting samples, one driver committed a traffic violation and was pulled over by a policeman, who when seeing the bottles of amber liquid in the car, believed that the driver was a bootlegger). Doisy followed the work of Danish researcher Henrick Dam, who had grown baby chickens on an artificial diet that contained no fats, and found that they were prone to hemmoraging. Dam also found this could be cured by a diet of hempseed, and was able to isolate the active principal. Doisy, with the assistance of graduate assistant Ralph McKee, was able to isolate two forms of this chemical (named K1 and K2).
Vitamin K, first reported by Dam, is short for Koagulationsvitamin, the German name given to it. Vitamin K functions to modify proteins by adding a carboxy group certain glutamine residues forming gamma-carboxyglutamate, which allows the protein to bind calcium. These modified proteins take part in the blood coagulation cascade and bone metabolism. Like other fat soluble vitamins (A and D) it is stored in fat tissue in the human body. Newborns are injected with a dose of vitamin K to prevent hemmoraging. It is found in green leafy vegetables such as spinach and Swiss chard and fruits including avacado, grapes, and kiwi fruit. For their work in discovering vitamin K, Doisy and Dam were awarded the 1943 Nobel prize in physiology or medicine.
Other awards won by Doisy include honorary degrees from Yale, Washington, Chicago, Illinois, St Louis, Gustavus Aldolphus College, and Paris Universities. He served on the League of Nations Committee for the Standardization of Sex Hormones in 1932 and 1935. He was president of the American Society of Biological chemists from 1943 to 1945, the Endocrine Society from 1948 to 1950 and the Society of Experimental Biology and Medicine from 1950 to 1951. In 1955 the biochemistry department of St. Louis University was named after him. He retired in 1965.
He died on October 23, 1986.
Carey, Charles W.; American Scientists; Infobase Publishing; 2006
Simoni, Robert D., Hill, Robert L., and Vaughn, Linda; "The Discovery of Esterone, Esterol, and Esterdiol and the Biochemical Study of Reproduction. The Work of Edward Aldebet Doisy"; The Journal of Biological Chemistry(2002)277:e7
Edward A. Doisy Nobel Autobiography
Edward Aldebert Doisy Wikipedia Entry
Monday, November 7, 2011
James Gregory was born on November 6, 1638 in Drumoak, Scotland. His father was a minister and died when Gregory was thirteen. His mother, whose uncle was a professor of mathematics, schooled the boy in geometry and had him attend grammar school in Aberdeen, Scotland. With his father dead, his education was seen to by his older brother David and he attended Marischal College in Aberdeen, graduating in 1657. Gregory studied optics and in 1663 published Optica Promota in which he described for the first time the construction of a reflecting telescope, also called a Gregorian telescope, honoring Gregory. He was not able to construct one because he did not have the skills required to prepare the mirrors.
A reflecting telescope is an optical telescope that uses one or more curved mirrors to reflect light from the object being viewed. It was invented as an alternative to a refracting telescope, in which light passes through lenses. Refracting telescopes suffer from the problem of chromatic aberration, in which, due to the fact that different colors of light have different indices of refraction through glass, some details can be blurry and show color blotches. An index of refraction is the ratio of the speed of light through a vacuum over the speed of light through a particular medium, in this case glass, and can used to determine how far a light beam is bent when it travels through one medium to another. The effect of the differences in the indices of refraction is that different colors will have different focal lengths for a particular telescope. Today nearly all large research-grade telescopes are reflecting telescopes. Without lenses, they do not suffer from chromatic aberration and have a wider spectrum of color, due to the fact that some wavelengths of light (particularly UV light) are absorbed by glass lenses. Another advantage of reflecting telescopes is that they can be made larger than refracting telescopes. The largest lens that can be practically created is only 1 meter in diameter, whereas reflecting telescope mirrors have been created that exceed 10 meters in diameter.
In 1663 Gregory went to London, England where he met some members of the Royal Society, including John Collins, Robert Hooke, and Sir Robert Moray. These friends introduced him to an optician named Rieve, who attempted to construct a telescope using Gregory's design, but he was unable to make the parabolic mirror to work to Gregory's satisfaction. Isaac Newton read Gregory's book and the two later corresponded. At that time the European continent was considered the center of mathematics research so in 1664 he left London for Padua, in the Venetian Republic, where he studied mathematics and published two works on proto-calculus, which bolstered his reputation and got him into the Royal Society when he returned to London in 1668. In 1669, with the help of Robert Hooke, he was appointed to a new chair in mathematics at the University of St. Andrews. He taught at St. Andrews for 6 years but did not enjoy his time there. Suspicious of his new ideas and his interest in higher mathematics his masters at the school shunned him and eventually withheld his salary and servants.
In 1674 he accepted a new professorship at the University of Edinburgh. At Edinburgh the university officials were more generous and he had the money he needed to establish an astronomy program. Sadly, in October of 1675 he suffered a stroke while he was showing the moons of Jupiter to his students. He died a few days later at the age of 37.
Chambers, Robert; "Biographical Dictionary of Eminent Scotsmen"; Volume 2; Blackie and Son, 1835
O'Connor JJ and EF Roberson; "Gregory Biography"; at history.st-andrews.ac.uk
Anon; "Biographical Information" for Gregory, James, at nahste.ac.uk
James Gregory Wikipedia Entry