Historical development 20th century

Historical developments of ESR dating, dosimetry and microscopy in the 20th century are described in reviews and the book updated in 2002.1 New works in early 21st century can be seen in recent and forthcoming proceedings.2 This report describes a brief introduction of the quantitative use of ESR in earth and planetary science, especially in dating, aimed in part at those who are not familiar with these applications and discuss new prospects and development of these interdisciplinary fields in the 21st century. 

Table 1.2 provides an overview of historic events in biocatalysis and biotechnology. It demonstrates that biotechnology is an old science, or even an old art. The big ideas and driving forces for biocatalysis in the 20th century were twofold first, the idea of catalysis as transition-state complementarity in 1944 and second, the development of molecular biology after 1978 to allow the design of enzymes and their production vehicles. 

In the first place, historical interest appears to have shifted from the classical to the modern period, and especially to the very recent past. Thus a new historical interest in physical organic chemistry is so considerable that Chapter 5 is devoted to it alone. There must be several reasons for this stress on 20th-century developments and it is tempting to speculate. It could be argued, for example, that there is little new to learn about classical branches of chemistry and that the subject is virtually exhausted. However, some major incursions in the last few years have demonstrated the fallacy of such a view, for in fact the development of (say) organic chemistry has been far more complex than most of us have realized until quite recently. In its institutional aspects, there is much to be learned about the design and construction of laboratories and about the growth and decline of individual schools all over Europe. However, it takes time for these perceptions to take root. 

Historically, polyanhydrides were developed in the textile industry during the first half of the 20th century as alternate fiber materials. " However, the modern polyanhydrides that are currently under investigation as drug delivery platforms represent a novel class of polymer that, unlike the polyesters, has been specifically developed for biodegradable applications. In particular, these polyanhydrides were specifically prepared in attempts to produce surface-eroding dosage forms. 

The Jewish problem , its terrible outgrowths in the 20th century, and the new rising phase of anti-Semitism in Europe 60 years after the Holocaust are all horrifying, yet I consider them as natural symptoms, concomitant signs, typical outward manifestations of a myths-directed society. Unfortunately, anti-Semitism is just one of the historically developed irrational hatreds with which the still imbalanced present world of the Homo sapiens sapiens is imbued. 

Helge Kragh is professor at the History of Science Department, Aarhus University, Denmark. He has published on the history of technology and physical sciences and is interested in the philosophy of science. His most recent book is Cosmology and Controversy The Historical Development of Two Theories of the Universe (Princeton, 1996), and he is now working on a history of physics in the 20th century. 

Historical The term A. was introduced by the apothecary C. F. W. Meissner in 1819 for alkali-like plant substances. The development of A. chemistry is illustrated by some dates and names morphine (1803 or 1816 Sertiimer), strychnine (1818 Pelletier and Caven-tou), solanine (1820 Desfosses), caffeine (1820 Runge), quinine (1820 Pelletier and Caventou), nicotine (1828 Posselt and Reimann), atropine (1831 Mein), codeine (1832 Robiquet), theobromine (1842 Woskresensky), cocaine (1860 Wohler), ephedrine (1887 Nagai), scopolamine (1881 Ladenburg and 1888 E. Schmidt), mescaline (1896 Heffter). The first A. synthesis was realized in 1886 by Ladenburg (coniine). In the 20th century A. chemistry is especially associated with the names Willstatter, Woodward, Schopf,... 

Unlike the employers, the employee organisations tend to be made up of members of similar trades or skills rather than from particular industries. This has its reason in the historic development of the trade unions to protect their members employment by restricting entry into a trade and so maintain a demand for those skills. In the early part of the 20th century national negotiations on behalf of groups of unions in an industry had become the practice but this is now being eroded by employment laws and a recognition that it may not always be for the benefit of all members to do so. 

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