Atomic Energy of Canada Limited

About: Atomic Energy of Canada Limited is a company organization based out in Ottawa, Ontario, Canada. It is known for research contribution in the topics: Zirconium alloy & Neutron. The organization has 4845 authors who have published 4826 publications receiving 102951 citations.

Sorption of strontium onto bacteriogenic iron oxides.

Abstract: Bacteriogenic iron oxides (BIOS) were obtained from a dilute, circumneutral groundwater seep, characterized with respect to mineralogy, and examined for their ability to sorb aqueous Sr2+. BIOS were composed of microbial sheaths encrusted in 2-line ferrihydrite. Sorption experiments indicated that Sr remained completely unbound at pH 7.6). EXAFS analysis of Sr-loaded BIOS failed to elucidate whether Sr sorption occurred on sites specific to the mineral or microbial fraction, but indicated that sorption likely occurred by outer-sphere complexation between BIOS and hydrated Sr2+. Sorption experiments showed that, at low ionic strength (I = 0.001 M), sorption followed a Langmuir isotherm (Smax = 3.41 mol Sr (g of Fe)1−, Kads = 1.26). At higher ionic strength (I = 0.1 M), there was significant inhibition of Sr sorption (Smax = 1.06 mol Sr (g of Fe)1−, Kads = 1.23), suggesting that sorption to BIOS occurs by outer-sphere complexation. The r...

Singlet oxygen: a major reactive species in the furocoumarin photosensitized inactivation of E. coli ribosomes.

Abstract: — The skin photosensitizing furocoumarins, 8-methoxypsoralen (MOP) and 4,5′,8-trimethylpsoralen (TMP), inactivate E. coli ribosomes in vitro, on UV irradiation at 313 nm. Purging the solutions with N2 protects the ribosomes considerably against photoinactivation (75% with MOP and 80% with TMP). In air, the ribosome photoinactivation is mainly due to singlet oxygen (1O2), since the presence of NaN3 and other 1O2 quenchers protects the system and the inactivation is enhanced in D2O. Although 1O2 dominates as the inactivating species, the possibility of additional (∼15%) minor mechanisms involving free radicals exists. However, O-2 does not appear to be the damaging species, since superoxide dismutase does not provide any protection. Photosensitization of the partially purified enzyme, phe-tRNA-synthetase with MOP or TMP shows inactivation and protection curves similar to those seen with the ribosomes. On the other hand, unfrac-tionated tRNAphc is not photosensitized under similar conditions, although it shows self-photosensitization. It is likely that in the furocoumarin-sensitized ribosomes, the primary events of photoinactivation are associated with the proteins.