Rapid and efficient separation/purification of pure metallofullerenes M(x)@C(n) (M = metal; x = 1, 2; n > 70) and carbide metallofullerenes of the type M(y)C(2)@C(n-2) (y = 2, 3, 4; n - 2 > 68) has been reported. The present method utilizes rapid and almost perfect preferential formation of TiCl(4) (generally known as a Lewis acid)-metallofullerene complexes, which easily decompose to provide pure metallofullerene powders by a simple water treatment. The present method enables one to separate the metallofullerenes up to >99% purity within 10 min without using any type of high-performance liquid chromatography (HPLC). It is found that the oxidation potentials of the metallofullerenes are crucial factors for efficient purification. The current separation/purification technique may open a brand-new era for inducing further applications and commercialization of endohedral metallofullerenes.
The accident at the Fukushima Daiichi nuclear power plant caused serious radiocesium (137Cs) contamination of forest ecosystems located in mountainous and hilly regions with steep terrain. To understand topographic effects on the redistribution and accumulation of 137Cs on forest floor, we investigated the distribution of Fukushima-derived 137Cs in forest-floor litter layers on a steep hillslope in a Japanese deciduous forest in August 2013 (29 months after the accident). Both leaf-litter materials and litter-associated 137Cs were accumulated in large amounts at the bottom of the hillslope. At the bottom, a significant fraction (65%) of the 137Cs inventory was observed to be associated with newly shed and less degraded leaf-litter materials, with estimated mean ages of 0.5–1.5 years, added via litterfall after the accident. Newly emerged leaves were contaminated with Fukushima-derived 137Cs in May 2011 (two months after the accident) and 137Cs concentration in them decreased with time. However, the concentrations were still two orders of magnitude higher than the pre-accident level in 2013 and 2014. These observations are the first to show that 137Cs redistribution on a forested hillslope is strongly controlled by biologically mediated processes and continues to supply 137Cs to the bottom via litterfall at a reduced rate.
(M. Atarashi-Andoh).
Highlights (3 to 5 bullet points, maximum 85 characters per bullet point)• Spatial variation in air dose rates in a mountainous area was investigated• Measurements obtained by KURAMA-II, NaI detectors, and airborne surveys were compared• Radiocesium deposition was greater on ridges than in valley bottoms• Elevation and slope aspect strongly affected air dose rates 1 Catchment-scale distribution of radiocesium air dose rate in a mountainous 1 deciduous forest and its relation to topography 2 3 Abstract 4 A large number of air dose rate measurements were collected by walking through a 5
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