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1. Radiation effects on the integrity of paper

Author

D’Almeida, Maria Luiza Otero, Barbosa, Patrícia de Souza Medeiros, Boaratti, Marcelo Fernando Guerra, and Borrely, Sueli Ivone

Subjects
*PAPER disinfection, *RADIATION doses, *CELLULOSE chemistry, *EUCALYPTUS, *COBALT isotopes, *GAMMA rays, *WOOD-pulp
Abstract

Abstract: Books and documents attacked by fungi and insects have already been treated by radiation for disinfestations purposes. However, there is still need to investigate the influence of radiation on the cellulose paper structure. The aim of this research was to study the effects of radiation on paper properties, especially those related to strength and appearance. Paper sheets for this study were prepared in the laboratory, using bleached eucalyptus pulp as raw material. No additives were used to concentrate the attention only on the effects of irradiation on the pure cellulose matrix. The samples were irradiated at IPEN''s 60Co Gammacell irradiator with six radiation doses, from 3 to 15kGy at the dose rate 0.817Gy/s. The properties of paper sheets were tested after irradiation and compared with unirradiated samples according to ISO methods. No significant changes were detected in paper samples irradiated up to 15kGy. [Copyright &y& Elsevier]

Published
2009
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3. The Heterogeneity of the High Molecular Weight B12 Binder in Serum

Author

Christine Lawrence

Subjects
Electrophoresis, Male, Paper, Immunology, Size-exclusion chromatography, Beta-Globulins, Biochemistry, Blood serum, Column chromatography, Transcobalamin, Alpha-Globulins, Humans, Cyanocobalamin, Cellulose, Chromatography, Binding Sites, Chemistry, Blood Proteins, Cell Biology, Hematology, Blood Protein Electrophoresis, Blood proteins, Molecular Weight, Cobalt Isotopes, Vitamin B 12, Blood chemistry, Sephadex, Chromatography, Gel, Female
Abstract

The binding of vitamin B12 by serum proteins was studied by separating Co57B12-enriched serum by Sephadex gel filtration, column chromatography with DEAE-cellulose, and paper electrophoresis. Each method of separation yielded two discrete B12-binding fractions. However, the analysis of each serum by all three separation technics indicated that one of the fractions was, in each case, bipartite. The "high" molecular weight B12-binding fraction defined by Sephadex gel filtration consisted of transcobalamin I and just part of the transcobalamin II fraction. The remaining portion of transcobalamin II was eluted from Sephadex gel in a "low" molecular weight fraction. Thus, transcobalamin II, equivalent to the β-globulin B12-binder, consisted of both "high" and "low" molecular weight components. This suggests that there are at least three serum proteins that can bind vitamin B12: two β-globulins, together comprising the transcobalamin II fraction and differing in molecular weight; and transcobalamin I.

Published
1969