Introduction long-time

It is one of the peculiarities of herbal drugs that their indications have for the most part been determijied empirically. The reason is easily understood most herbal drugs have been used for a very long time to alleviate or cure illnesses and more especially disorders. Their introduction in therapeutics happened at a time when pharmacodynamics and pharmacokinetics were unknown concepts, when there was no Medicines Act to require proof of the quality, efficacy, and innocuity of herbal medicines. Today, when introducing a new medicine, extensive investigations are required in the interest of safety. To many the requirement of the proof of activity of such a drug as chamomile appears to be superfluous, but nevertheless, as a representative of a scientifically oriented pharma-... 

Most, if not all, textbooks and courses of QM proceed in a similar axiomatic way. At the end of the introduction to QM, most, if not all, students are confused. It takes a long time, several advanced courses, graduate school and often more to master QM. It is ironic that current masters of QM also internalize the paradigm of QM instruction that initially confused and frustrated them, and thus instruct new students in the same way. As a result, those students who take QM as part of a general education and not as the first step of a career in Physics, are left confused forever. I believe this constitutes a failure of the Physics community to communicate to humanity its most precious, successful and beautiful accomplishment. 

From a historic perspective glycosyl chlorides and bromides introduced, respectively, by Michael [2] and Koenigs and Knorr [3] were the most widely used donors in the saccharide synthesis for a very long time. The introduction of 1,2-orthoesters in 1964 [4] was the first important attempt to find an alternative to the Koenigs-Knorr method. However, Paulsen in his 1990 review of reliable donors for glycosyl... 

Surface engineering by means of fluorination is an effective way to change surface properties, and is used for both polymer surfaces and inorganic substrates. Polymer surface fluorination has been around a long time. The first patent we know of dates back to 1938,1 but it was only in the 1970s that the introduction of several major industrial applications led to a rapid acceleration in development. 

The problem of background fluorescence has been largely overcome with the introduction of time-resolved fluorimetry. This technique relies on the use of fluorophores with a long-lived fluorescence which can be measured... 

For a long time metal carbenes have been either classified as Fischer- or Schrock carbenes, depending on the oxidation state of the metal. Since the introduction of N-heterocycHc carbene complexes this classification needs to be extended because of the very different electronic character of these ligands. Carbenes—molecules with a neutral dicoordinate carbon atom—play an important role in all fields of chemistry today. The first examples in the field of organic chemistry were published by Doering and Hoffmann in the 1950s [1], while Fischer and Maasbol introduced them to organometallic chemists about ten years later [2,3]. But it took another 25 years until the first carbenes could be isolated [4-8]. 

Alihough ihc Latin natrium has been around for a long time. Ehe IUPAC has not recommended its use previously, and Na has been universally called "iodide." In view of the phasing out of terms like "cuprous" and "ferric, the introduction of hitherto unused latinized names is unexpected.]... 

Jain (20), in his introduction, notes that the direct injection of the blood sample does not give "ghost" or interfering peaks. The column can be used for a long time. The method is not limited to ethanol, since methanol, isopropanol, and acetone as well as toluene, methylethylketone, and xylene (associated with glue sniffing) can be quickly determined. 

Emery is a mixture of granular corundum of dark color, magnetite and hematite, sometimes with spinel. Quartz may be present For a long time emery was supposed to be an ore of iron. Until the introduction of artificial abrasives, emery was much used for such purposes. 

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