Tailoring of the Properties of Amorphous Mesoporous Titanosilicates Active in Acetone Condensation.

Amorphous mesoporous materials are promising as catalysts for processes involving or forming bulk molecules. In a reaction such as acetone condensation to form mesitylene, an effective catalyst should not only have a developed porous structure but also have active centers of acidic and basic types. The sol-gel approach allows one to obtain titanosilicates with such characteristics.

[Photo-induced destruction of DOPA-melanin].

Studies of the effect of illumination at different wavelengths revealed a high stability of DOPA-melanin to the visible light. Contrariwise, UV-visible light of high intensity upon prolonged (many hours) illumination caused a significant bleaching of the diluted aqueous solution of the pigment. The absorption spectrum of DOPA-melanin in the UV- and IR-regions did not differ from the initial one; however, the illuminated pigment acquired an ability for fluorescence.

[A spectrofluorometric method of recording oxidation products of eumelanin destruction].

Dynamics of oxidative destruction of DOPA-melanin and melanin proteins was studied after treatment with 3% hydrogen peroxide within 60 min at 100 degrees. The pigments were estimated by absorption at 400 nm as well as by means of spectrofluorimetric patterns both in total preparation and in preparation obtained after fractionation on Tojapearl-55 and Tojapearl-40. Intensive fluorescence in the region 500-510 nm was detected within initial steps of oxidation while the absorption spectrum was unaltered.

[Estimation of various quantitative methods for the determination of native and formaldehyde-treated proteins].

Quantitative estimation of native and treated with 4% formaldehyde albumin, pepsin, lysozyme, histone, gelatin and other proteins was carried out using four procedures--biurete, Lowry-Folin, ninhydrin and coomassy R-250. Chromogeneity of proteins in corresponding color reactions was expressed as OD per 100 micrograms of nitrogen estimated by means of Kjeldahl micromethod. The proteins were treated with formaldehyde in corresponding buffers at 20 degrees within 7 days, non-bound or loosely bound formaldehyde was dialysed.

[Study of volatile substances produced during the melanoidin synthesis in the model system: glyceraldehyde + glycine].

Volatile compounds produced during the synthesis of melanoidins in the model system: glyceraldehyde + glycine were studied. The reactions that resulted in the formation of melanoidins yielded carbon dioxide and trace amounts of ammonia and carbonyl compounds. With a rise in the incubation temperature the browning rate and quantities of gaseous substances increased, although there was no correlation between the two latter parameters.