Sunday, July 13, 2014

Stanislao Cannizzaro

Stanislao Cannizzaro was born on July 13, 1826 in Palermo, Sicily, the fourth and youngest son of Mariano Cannizzaro and his wife Anna. Mariano was a magistrate in Palermo and the Director-General of the Sicilian Police. Cannizzaro was educated at home and in church schools and went to the University of Palermo to study medicine in 1841. Cannizzaro found the study of medicine to be tedious as he was more interested in chemistry. Unfortunately the university did not have facilities to study chemistry so Cannizzaro went to Naples where he met the physicist Macedonio Melloni, with whom he became friends and upon Melloni's recommendation he got a job working in the chemical laboratories of the University of Pisa working for Raffeal Piria.

Cannizzaro returned to Palermo in 1847 and served as an artillery officer in the 1848 rebellion. Also in 1848 he was elected to the Sicilian Parliament and served as its youngest member. After the fall of Messina on September 7, 1848 Cannizzaro was sent to Taorminna to organize resistance. When the rebellion collapsed Cannizzaro lived a life on the run eventually escaping to Marseilles, France in 1849. Cannizzaro toured France getting access to laboratories where he could and eventually he settled in Alessandria, Italy where he got a position as a professor of physical chemistry and mechanics at the National University in Alessandria. In 1855 Cannizzaro was called to the Chair of Chemistry at the University of Genoa. In 1861 he took a professorship at the University of Palermo where he remained for ten years. In 1871 Cannizaro was called to the professorship at the University of Rome.

Cannizzaro is most remembered for his work popularizing the ideas of another Italian chemist Amedeo Avagadro. Avagadro had proposed that equal volumes of two gasses at the same temperature and pressure would contain the same number of molecules and that the molecular mass of the molecules would be the sum of the atomic masses of the atoms of which the gasses are composed. Using this principal Cannizzaro developed a method for determining the molecular masses of gasses. At the time chemists were still trying to work out the uses of the words atomic and molecular. Cannizzaro's outline, prepared for his students at the University of Genoa, helped chemists understand that gasses are molecules composed of multiple atoms and have the molecular mass of the sum of the atomic masses of the atoms of which they are composed. For example, oxygen gas, composed of two oxygen atoms each having the atomic mass of 16, has the molecular mass of 32. For his work contributing to the understanding of the concepts of atom and molecule Cannizzaro was awarded the Copley Medal by the Royal Society of London in 1891,

Cannizzaro is also remembered for his work in organic chemistry, where he studied amines and aromatic compounds. Aromatic compounds are compounds that contain a benzene ring. The Cannizzaro reaction is the reaction where an aldehyde is reacted with a base and the reaction produces the alcohol and carboxylic acid that correspond to the aldehyde.

Cannizaro died on May 10, 1910.


References:

Anon.; "Stanislao Cannizaro"; retrieved from chemheritage.org

Thorpe, Sir Thomas Edward; "Stanislao Canniaro" in Essays in Historical Chemistry; MacMillian and Co.; 1902

Stanislao Cannizaro Wikipedia Entry

Sunday, June 29, 2014

Peter Waage

Peter Waage was born on June 29, 1832 on the island Hidra, near Flekkefjord in Norway. His father, also named Peter, was a ship-master and owner so he was often away from home and Waage was raised and taught by his mother, Regine. Waage learned to read by age four and spent his youth collecting minerals, plants, and insects. He graduated high school in Christiana and began studying medicine at the university. After his first division he switched to chemistry. in 1858 Waage won the Crown Prince's Gold Medal for a paper he wrote about oxygen containing organic acids and he earned his doctorate in 1859. After graduating Waage won a scholarship to study in France and Germany, Waage as appointed as a lecturer in 1861 and professor of chemistry in 1866 at the University of Kristiana.

Waage is most remembered for his discovery, with his brother-in-law Otto Guldberg, of the law of mass action. The law of mass action says that the rate of a chemical reaction is proportional to the concentration of the chemical reacting. For the chemical reaction A + B --> AB the rate of the reaction is =k[A][B], where [A] and [B] are the concentrations of the reactants A and B and k is the the rate constant. The rate constant, k, varies depending on what the reaction is. Waage and Guldberg also studied the effects of temperature on chemical reactions. Because their paper was published in Norwegian it was largely unnoticed. The paper was later published in French and German and gained wide acceptance when the results were repeated by William Esson and Vernon Harcourt of Oxford University.

Waage and Guldberg were brother-in-laws twice over. Waage and Guldberg married sisters and after Waage's first wife died he married Guldberg's sister. Waage also discovered ways of preparing unsweetened condensed milk and sterile canned milk. Waage developed a condensed fish meal used as rations by the Norwegian Navy.

Waage died on January 13, 1900.


References:

Albe, Joseph and Smith, Michelle; "Otto Guldberg and Peter Wage";

Ringnes, Vivi; "Peter Wage"; Retrived from vitten.no

Peter Wage Wikipedia Entry

Sunday, June 22, 2014

Hermann Minkowski

Hermann Minkowski was born on June 22, 1864 in Aleksotas, Lithuania, then part of Poland and the Russian Empire. He was the third son of Lewin Minkowski, a Jewish merchant and his German wife Rachel. When Minkowski was 8 the family moved to Konigsberg, Germany (now Kaliningrad, Russia) to escape persecution and where he attended gymnasium school and showed an ability for mathematics. Minkowski attended the University of Kongisberg starting in 1880. He went to the University of Berlin for a three terms and shared a the Grand Prix des Sciences Mathematiques from the Paris Academy of Sciences with English mathematician Henry J.S. Smith in 1881, when he was 18. Minkowski earned his doctorate in 1885.

After two years of obligatory military service in 1887 Minkowski was appointed privatdozent at the University of Bonn. In 1892 Minkowski became an asOsociate professor at Bonn. In 1894 Minkowski joined the faculty of Zurich Polytechnic, where one of his students was Albert Einstein. In 1902 Minkowski took a chair in mathematics which had been created especially for him at Gottingen University. Minkowski remained in Gottingen util his death.

Minkowski is most remembered for his work on geometry and space-time. In Euclidean geometry there are three dimensions, representing the three dimensions of space. Minkowski incorporated a fourth dimension representing time to the Euclidean system where time and space are interlinked together forming a whole four dimensional system. This four dimensional space is called Minkowski space-time and arises naturally when consequences of relativity are considered.

Minkowski died suddenly of appendicitis on January 12, 1909.


References:

O'Connor, J.J. and Robertson, E.F.; "Hermann Minkowski"; MacTuror; Retrieved from: http://www-history.mcs.st-andrews.ac.uk/

Manhanti, Subodh; "Hermann Minkowski: Founder of Geometry of Numbers"; Dream 2047 Vol.14 (May 2012) p40-42

Hermann Mikowski Wikipedia Entry

Sunday, June 15, 2014

Thomas H. Weller

Thomas Huckle Weller was born on June 15th 1915 in Ann Arbor, Michigan. Born into a family of physicians, his father served as chair of pathology at the University of Michigan Medical School.Weller attended the University of Michigan where he studied biology earning his BA in 1936. He completed his masters a year later and then went to  Harvard Medical School where he studied tropical medicine, graduating in 1940. Weller began his residency at Children's Hospital in Boston in 1941, but his training was interrupted by World War II and three years of service in the United States Army where he earned the rank of major and he headed the departments of bacteriology, virology and parisitology at the Army research station in Puerto Rico. After the war Weller returned to Harvard and the Department of Comparative Pathology and Tropical Medicine where he worked under John Franklin Enders.

Enders was working on growing viruses in culture. Viruses, unlike bacteria, are unable to reproduce on their own, so strictly speaking they are not living organisms. Viruses require a host cell in order to reproduce. Each cell has a mechanism by which it reproduces itself. Viruses take over this mechanism and use it to produce more viruses. Viruses grown in the laboratory must be grown in a cell culture. Different viruses infect and use different types of cells to reproduce. Enders and Weller were studying which types of cultured cells could be used to grow different types of viruses. Working with Enders, Weller was the first to be able to grow poliovirus in culture. Poliovirus enters humans via the the cells of the alimentary canal and migrates to other cells. It can infect motor neuron cells causing paralysis. For their development of the ability to cultivate the poliovirus Weller, Enders, and Frederick C. Robbins were awarded the 1954 Nobel Prize for Physiology and Medicine. With the ability to grow poliovirus in culture Jonas Salk was able to create a vaccine for polio and the disease has virtually been eliminated.

In 1954 Weller was appointed the Richard Pearson Strong Professor of Tropical Public Health, which he remained until 1983. In addition to his work growing polio virus, Weller also isolated and grew varicella virus (the virus that causes chicken pox and shingles). He was also able to grow rubella and cytomeglovirus. Weller was elected to the National Academy of Sciences in 1964. Weller was made professor emeritus in 1984.

Weller died on August 23, 2008.


References:

McIntosh, Kenneth; "Thomas H. Weller:1915-2008"; National Academy Press; 2011

Roache, Christina; "Thomas H. Weller, Nobel Laureate, Professor Emeritus, Dies"; Harvard School of Public Health press releases; August 26, 2008

Thomas Weller Nobel Biography

Thomas Weller Wikipedia Entry



Sunday, April 13, 2014

Bruno Rossi

Bruno Benedetto Rossi was born on April 13, 1905 in Venice, Italy. His father, Rino, was an electrical engineer and had taken part in the electrification of Venice. Rossi was educated at home until he was 14, after which he attended ginasio (gymnasium) and liceo (high school) in Venice. He began his university studies at the University of Padua and finished his laurea (doctorate) at the University of Bologna in 1927. In 1928 Rossi took a job as an assistant at the Physics Institute of the University of Florence. Initially Rossi was at a loss to find a project to work on with the limited resources of the institute, but after reading a paper on cosmic rays, Rossi began studying them and developed an improved instrument, called a coincidence circuit, allowing him to study them. The instrument consisted of two Geiger counters, one mounted above the other, where metal plates could be inserted in between. By varying the type and thickness of the metal plates Bruno could determine the penetrating power of the cosmic rays.

Cosmic rays are charged atomic particles that bombard the Earth originating from the supernovas of large stars and in smaller amounts from active galactic centers. The surface of the Earth is protected from these charged particles by the Earth's atmosphere and magnetic field, although some reach the Earth's surface. Life on Earth would not survive were it not for this protection. Initially these particles were believed to be a form of electromagnetic radiation, but in 1927 Jacob Clay measured the amount of rays detected as he voyaged from Netherlands to Java and reported that the amount of rays hitting the Earth's surface changed with latitude with a minimum at the equator. This demonstrated that the "rays" were not photons and must be charged particles that were deflected by the Earth's magnetic field.

In 1932 Rossi became a professor of experimental physics at the University of Padua. In 1938 he was dismissed from his professorship because he was Jewish. After  a brief stays at the Bohr Institute in Copenhagen and University of Manchester, Rossi emigrated to the United States where he took a position at Cornell University in 1940. In 1943 Rossie joined the Manhattan Project in Los Alamos, New Mexico where he was co-chair, with Hans Straub, of the "detector group", which was responsible for designing detectors used by the scientists developing the atomic bomb.

In 1946 Rossi took a professorship at the Massachusetts Institute of Technology at the new Laboratory of Nuclear Science. At MIT Rossi focused on studying newly discovered subatomic particles. Rossi focused on developing detectors that could be launched into space to study cosmic rays that are not affected by the Earth's atmosphere and magnetic field. Rossi retired in 1970, but continued teaching. Awards won by Rossi include the Rumford Prize from the American Academy of Arts and Sciences (1976), the Elliot Cresson Medal from the Franklin Institute (1974) and the National Medal of Science (1985). Rossi was also awarded honorary doctorates from the Universities of Palermo, Durham, and Chicago.

Rossi died on November 21, 1993, suffering a cardiac arrest.


References:

Clark, George W.; "Bruno Benedetto Rossi: 1905-1993"; in Biographical Memoirs Vol. 75 (1997) National Academy Press

Clark, George W.; "The Contributions of Bruno B. Rossi to Particle Physics and Astrophysics"; Retrieved from: http://www.brera.unimi.it

Bruno Rossi Wikipedia Entry




 

Sunday, April 6, 2014

Feodor Lynen

Feodor Felix Konrad Lynen was born on April 6, 1911 in Munich, Germany. His father, Wilhelm Lynen, was a professor of mechanical engineering and his mother, Frieda, was the daughter of an industrialist. Lynen completed his primary and secondary education in Munich and attended Munich University studying chemistry. He completed his Ph.D. in 1937 with a dissertation identifying the toxic substance in amanita mushrooms. After graduation Lynen remained at Munich University becoming a chemistry lecturer in 1942, an assistant professor in 1947, and biochemistry professor in 1953. When World War II broke out Lynen was exempt because of injuries he sustained in a skiing accident. In 1956 he became director of the Max Plank institute for Cellular Chemistry.

Lynen's research dealt with determining the biochemical pathways by which cells produce fatty acids and sterols. Working with Konrad Bloch, he discovered the pathway by which cholesterol is synthesized. Later he determined the structure of acytel-coenzyme A. Acetyl-CoA is an important biochemical intermediate. It feeds two carbon acetic acid fragments from glycolysis (the initial steps by which cells break down glucose) into the citric acid cycle to generate cellular energy. It also is the basis of fatty acid and cholesterol synthesis using the two carbon acetate to build longer carbon chains to store energy or produce bigger carbon molecules. For their work Lynen and Bloch were awarded the Nobel Prize in Physiology and Medicine in 1964.

Other awards won by Lynen include the Grand Cross of Merit with Star and Sash of the Federal Republic of Germany in 1965, Norman Medal of the German Society for Fat Research in 1967, the Pour le mérite für Wissenschaften und Künste in 1971, and the Austrian Decoration for Science and Art in 1972.

Lynen died on August 6, 1979.

References:

Kresge, Nichole, Simoni, Robert D., and Hill, Robert L.; "Biotin Dependent Enzymes: the Work of Feodor Lynen"; Journal of Biological Chemistry (2009)284:e6-e7

Feodor Lynen Nobel Biography

Feodor Lynen Wikipedia Entry


Sunday, March 16, 2014

Martinus Beijernick

Martinus Willem Beijernick was born on March 16, 1851 in Amsterdam, Netherlands. Beijernick's father's tobacco business also failed that year and the family moved to Naarden, where he found work as a clerk working for the Holland Railway Company. Due to the family's financial situation Beijernick was educated by his father until he was 12 when he went to elementary school and then secondary school in Haarlem. With the encouragement of his science teacher Beijernick developed an interest in botany and at 15 he won a prize for his collection of plant samples that included 150 different species.

With the help of his family, Beijernick entered Delft Polytechnical Academy and although he studied chemistry his main interest remained botany. While there he met J. H. Van Hoft who he remained friendly throughout his career and served as an adviser to Beijernick. Beijernick earned a bachelors in chemical engineering in 1872 and then when to the University of Leiden where he earned his doctorate in 1877. While working on his doctorate Beijernick taught, but he was a poor teacher who berated his students for wrong answers and he did not remain in one teaching position for long. In 1885 Beijernick became a microbiologist at the Netherlands Yeast and Alcohol Manufactory in Delft. In 1895 he established the School of Microbiology at Delft Polytechnical.

Beijernick was unique among microbiologists at the time in that he researched the microorganisms that affected plants rather than those that affect humans. He was the first to discover that viruses were smaller than bacteria when he found that he was unable to filter the tobacco mosaic virus unlike bacteria. He was the first to isolate a sulfate reducing bacteria, the first microorganism that did not use carbon as a source of nutrition. He was also the first to isolate bacteria that complete nitrogen fixation. Nitrogen gas makes up 78% of the atmosphere but because the nitrogen-nitrogen bond is so stable nitrogen gas does not react with other atoms. Nitrogen fixating bacteria reduce nitrogen gas to become ammonia, which can react with other atoms and is used by plants as a nitrogen source. This is an important source of nitrogen, that is used to make amino acids, which are used to synthesize proteins by living organisms.

Beijernick retired in 1921 and died on  January 1, 1931.


References:

Chung, King-Thom and Ferris, Dean Hunter; "Martinus Willem Beijernick (1851-1931) Pioneer of General Microbiology"; ASM News (1996)62:539-543

Johnson, James; "Martinus Willem Beijernick: 1851-1931"; retrieved from apsnet.org.

Martinus Beijernick Wikipedia Entry