We give a necessary and sufficient condition for the preservation of finite products by a reflection of a variety of universal algebras into an idempotent subvariety. It is also shown that simple and semi-left-exact reflections into subvarieties of universal algebras are the same. It then follows that a reflection of a variety of universal algebras into an idempotent subvariety has stable units...

The evaluation of extraction protocols for untargeted metabolomics approaches is still difficult. We have applied a novel stable isotope-assisted workflow for untargeted LC-HRMS-based plant metabolomics , which allows for the first time every detected feature to be considered for method evaluation. The efficiency and complementarity of commonly used extraction solvents, namely 1 + 3 (v/v) mixtu...

Tris(3-bromo-acetylacetonato) chromium(III) as an inert and very stable complex with a good leaving group was synthesized using as-prepared Cr(acetylacetonate)3. Highly ordered nanoporous silica (LUS-1), with some great features, was functionalized with 3-aminopropyltriethoxysilane. Then the as-prepared product was modified with tris(3-bromo-acetylacetonato) chromium(III) under mild reaction co...