16767 research outputs found
Sort by
Concert: The Angela and William Haines Young Concert Artists Residency, Anthony Trionfo, flute
Get PDFMS Teams meeting with Ginny-cat
No full textOn a Tuesday in June, during a MS Teams meeting, my cat Ginny required attention. She walked behind my desktop computer and disabled my keyboard and mouse! This is unique to the work-from-home experience
The violin case
No full text© 2020 Elsevier B.V. Three humorous episodes, reproduced here, illustrate debates that played out on the pages of Cognition under the aegis of its founding editor, Jacques Mehler. These are the formal structure of language, the mechanisms by which speech unfolds in time, and the constrained creativity of ordinary language use
Fe(III)-polyuronic acid photochemistry: radical chemistry in natural polysaccharide
No full text© 2021, The Author(s), under exclusive licence to European Photochemistry Association,European Society for Photobiology. The photochemistry of Fe(III) coordinated to natural uronate-containing polysaccharides has been investigated quantitatively in aqueous solution. It is demonstrated that the photoreduction of the coordinated Fe(III) to Fe(II) and oxidative decarboxylation occurs in a variety of uronate-containing polysaccharides. The photochemistry of the Fe(III)-polyuronic acid system generated a radical species during the reaction which was studied using the spin trapping technique. The identity of the radical species from this reaction was confirmed as CO2•− indicating that both bond cleavage of the carboxylate and oxidative decarboxylation after ligand to metal charge transfer radical reactions may be taking place upon irradiation. Degradation of the polyuronic acid chain was investigated with dynamic light scattering, showing a decrease in the hydrodynamic radius of the polymer assemblies in solution after light irradiation that correlates with the Fe(II) generation. A decrease in viscosity of Fe(IIII)-alginate after light irradiation was also observed. Additionally, the photochemical reaction was investigated in plant root tissue (parsnip) demonstrating that Fe(III) coordination in these natural materials leads to photoreactivity that degrades the pectin component. These results highlight that this Fe(III)-polyuronic acid can occur in many natural systems and may play a role in biogeochemical cycling of iron and ferrous iron generation in plants with significant polyuronic acid content. Graphic abstract: [Figure not available: see fulltext.