Photolysis of the d-glycosides: α benzylfructofuranoside, β benzylfructopyranoside,and α and β phenyl,benzyl and β phenylethyl glucosides; and the bearing of the data upon the transfer of energy within molecules

Direct absorption of light by glycosides dissolved in water has been discovered to produce changes in optical activities and formation of material which reduces the Shaffer, Hartmann, Somogyi reagent. Comparison of these measurements indicates in many cases the same products as are formed by hydrolysis in acid. The β glucosides and α fructoside, however, apparently give optically inactive photolytic products.Absorption spectra were obtained for α benzylfructofuranoside and β benzylfructopyranoside, and were found to be the same in the near ultraviolet as those previously obtained for benzyl glucosides and benzyl alcohol.The absorption spectrum for freshly purified fructose gives a deeper minimum about λ240 mμ than the previously reported values. The latter, however, were approached when the dry crystals had stood in air for several months although no change occurred in their sp.rot., m.p. or general apperance.All the glycosides studied were white crystalline compounds. Less than five per cent. of the ultraviolet light of λ254 mμ they absorb produces reaction; nevertheless, the apparatus and procedures available were adequate to study the reaction conveniently in monochromatic light of this wave-length.The absorption spectra, the products of photolysis, and the quantum yields, the latter based on the reducing material formed, lead to the hypothesis that the photochemical reaction is produced by an intramolecular transfer of absorbed energy from the aglycone to the hemiacetal oxygen bridge which is the reactive center. The efficiency of this transfer is, as expected, greater for benzyl than for phenylethyl glucosides but phenyl glucosides, contrariwise, are the least efficient.The structure and energy possessed by the glycoside outside the aglycone have no measurable effect on the efficiency of the photochemical reaction when followed by measuring the reducing material produced although they change up to one hundred thousand fold the rates of the thermal hydrolyses in acid.     

Who is using the .co.uk domain? Professional and media adoption of the web

This paper reports on a survey of 221 web sites chosen at random from a subset of the .co.uk area of the Internet. A breakdown of the types of business represented shows that whilst computing companies continue to have a sizeable presence on the web, certain other types of business now also have a relatively large number of sites. The survey found many media-related businesses and professional-based companies and practices, reflecting the increasing use of Information Technology in these areas but also the increasing knowledge about the Internet that is needed or helpful in many types of job. The results are consistent with general business use of the web in the UK still being in an experimental phase of web site creation by those who can rather than by those who should.     

A guide to the literature on the history of engineering available in the cooper union library: Cooper Union Bulletin. Engineering and science series,Number 28, 46 pages, 18 × 2S CMS., paper. New York,The Cooper Union for the Advancement of Science and Art, 1946.

The linear logarithmic relations between deformation and temperature and pressure, previously empirical, have been directly derived from the defining equations for compressibility and thermal expansivity and shown to apply to all three stages of every deformation.Gibbs' thermodynamic potential function is shown to lead directly to simple and exact expressions for the energy of change of phase and of deformation within any one phase. The latter, a general equation of state, amounts to a simple relation between the four internal pressures.The derived deformation and energy functions are applied to some experimental data on steel tape which included thermal and relaxation observations.Thermodynamic relations governing both elastic and viscous behavior are developed. Plastic behavior involves both single phase and multiple phase applications of the second law. Precise thermal measurements should give the constants.