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A novel transformation of primary amines to the corresponding N-monoalkylhydroxylamines is described. The three-step protocol involves selective mono-cyanomethylation of primary amines, regioselective formation of nitrones by m-CPBA oxidation, and hydroxylaminolysis of the nitrones with hydroxylamine hydrochloride. The method is applicable for a wide range of primary amines, including alkyl, benzyl, and chiral.

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In this paper, we report the petrographic properties of visible tephra layers sampled from two drill cores (SG93 and SG06) from Lake Suigetsu, central Japan, because no fundamental petrographic data including the refractive indices of minerals and volcanic glass shards, the shapes of volcanic glasses, and mineral compositions of the Suigetsu tephra samples have been reported. The Suigetsu tephra layers can be broadly classified into those derived from calderas on Kyushu Island (e.g., Aso, Ata, and Aira) and those that derive from Daisen and Sambe volcanoes in the Chugoku district of southwest Japan. The tephra layers correlated with the Ulleung⊖Oki tephra from Ulleung Island on Japan Sea, the Sakate tephra which has a close relationship with the Sambe⊖Ukinuno tephra, and the scoria layer from an unknown source volcano were also found in the Suigetsu core samples. The Suigetsu tephra layer correlated with the San'in 1 tephra found in the drill core bored from Japan Sea can be also correlated with the Kuju-1 tephra which erupted from the Kuju caldera on Kyushu Island, based on the petrographic properties. The petrographic characteristics provide important constraints on the correlation and identification of tephras, which cannot be obtained by only the major element compositions of volcanic glass shards. However, the correlation of some tephra layers remains ambiguous. Therefore, additional geochemical data from volcanic glass shards including the concentrations of various trace elements are also necessary for a more rigorous identification and correlation of the Suigetsu tephra.

The major and trace element concentrations of volcanic glass shards from visible tephra layers in the SG93 and SG06 cores from Lake Suigetsu, central Japan, were determined by femtosecond laser ablation–inductively coupled plasma–mass spectrometry. The glass‐shard analyses, together with the petrographic properties of the tephra samples, allow the Suigetsu tephra layers to be broadly classified into tephras derived from calderas on Kyushu Island, and from Daisen and Sambe volcanoes in the Chugoku district of southwest Japan. The layers correlated with tephras from Kuju caldera and Daisen volcano, and with the younger Sambe tephras, have adakitic elemental features. A Suigetsu tephra sample correlated with the Sambe−Kisuki tephra based on petrographic properties has an elemental pattern similar to that of the Toya tephra from Hokkaido Island, northeast Japan. This match implies that tephras from northeast Japan, as well as Kyushu–Chugoku tephras, are possible correlatives of the Suigetsu tephra layers. Both petrographic properties and major–trace element data of volcanic glass shards are essential for robust tephra correlations, and hierarchical cluster analysis proved additionally useful in statistically evaluating relationships among the tephras.

Misfolding of the human protein alpha-synuclein results in toxic fibrils and the aggregation of Lewy bodies, which are a hallmark of Parkinson’s disease in brain tissue. Here we disclose a...

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