Vapor phase adsorption of organic compounds on octyl silicas

The influence of the modification of silica by octyltrichlorosilane with the formation of an oligomeric grafted layer (sample C8(II)) and additional silanization (sample C8(III)) on the thermodynamic adsorption characteristics (TACs) of different classes of organic compounds was investigated by gas chromatography. It was shown that the modification leads to decreased adsorption values for most of the investigated compounds (with the exception of alkanes, for which TACs on sample C8(II) approach the values observed on the initial support, due probably to additional interactions with silanol groups formed in modifying the surface with octyltrichlorosilane). It was established that blocking these silanol groups during additional silanization with trimethylsilane resulted in inert surfaces whose adsorption properties with respect to many compounds (including some capable of participating in strong specific interactions) approaches to the properties of octyl-silica with a close-packed grafted monolayer.     

Fullerenolates: metallated polyhydroxylated fullerenes with potent anti-amyloid activity

It has been revealed for the first time that sodium fullerenolate Na(4)[C(60)(OH)(～30)] (NaFL), a water soluble polyhydroxylated [60]fullerene derivative, destroys amyloid fibrils of the Aβ(1-42) peptide in the brain and prevents their formation in in vitro experiments. The cytotoxicity of NaFL was found to be negligibly low with respect to nine different culture cell lines. At the same time, NaFL showed a very low acute toxicity in vivo. The maximal tolerable dose (MTD) and LD50 for NaFL correspond to 1000 mg kg(-1) and 1800 mg kg(-1), respectively, as revealed by in vivo tests in mice using intraperitoneal drug injection. The observed pronounced anti-amyloid activity and low toxicity of NaFL make it a very promising lead drug for the development of potent fullerene-based therapeutic approaches for the treatment of amyloidoses, such as Alzheimer's disease and others.     

Synthesis of chiral mesoporous silicas with oligo(saccharide) surfaces and their use in separation of stereoisomers

Novel chiral mesoporous silicas (SBA-15 motif) with chemically bonded oligo(saccharides) (1, 3, and 7 glucose units) were obtained through the cocondensation of organosilicon derivatives of the oligo(saccharides) and silica precursors in the presence of polymer surfactant template under mild acidic conditions. The pore order and structure of the materials prepared were characterized by transmission electron microscopy and nitrogen adsorption. The direct application of the oligo(saccharide)-grafted SBA-15 stationary phases in the HPLC separations of stereoisomers was demonstrated for the first time.     

Parametric analysis of kinetic models, XI. Influence of the number of active sites

The influence of active sites number on the stationary characteristics of kinetic models is analyzed for some nonlinear schemes of conversion on catalyst surface. Mechanisms involving one and two types of active sites are considered. A possibility of critical effects is shown.     

1,5-Disubstituted 1,1,5,5-tetranitro-3-pentanones

Conclusions The reaction of salts of 1,1,1,3,5,5,5-heptanitropentane and 1,5-difluoro-1,1,3,5,5-pentanitropentane with oxidizing agents in concentrated sulfuric acid or trifluoroacetic acid yielded 1,1,1,5,5,5-hexanitro-3-pentanone and 1,5-difluoro-1,1,5,5-tetranitro-3-pen-tanone.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2366–2368, October, 1984.     

Temperature investigation of low-frequency Raman spectra of monocrystalline malononitrile

The Raman spectroscopy method is used to investigate phase transition in crystalline malononitrile. Polarized phonon spectra of a substance are studied in three crystalline phases: T, F, and T'. It is shown that phase transitions are not accompanied by significant restructuring of the crystal lattice, which, probably, preserves monoclinic syngony.Kuzbass Polytechnical Institute. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 21–24, December, 1992.