Iron catalysts with N-ligands for carbene transfer of diazo reagents

Transition-metal-catalyzed carbene transfer reactions, involving diazo compounds and their precursors, are powerful tools for creating new C-C bonds. Depending on the involved catalytic system, the carbene insertion can efficiently be driven towards a specific functional group for the synthesis of a wide portfolio of fine chemicals. The present report is focused on the catalytic activity of iron catalysts in promoting alkene cyclopropanations, C-H and X-H (X = N, O, S, Se, Si, Sn, Ge) functionalizations. Porphyrin, porphyrinoid and non-heme iron complexes are discussed by analyzing experimental studies and theoretical calculations performed for proposing reaction mechanisms. The catalytic activity of artificial iron biocatalysts is also briefly reported in order to underline the similarities and differences between reaction mechanisms mediated by modified biocatalysts and synthetic catalysts. This review summarizes the achievements made in this field since 2006

Gender equality in library science and book history Italian journals: a focus on boards, authors and peer-reviewers

The presence of women in Italian open access journals in library science and book history has never been subject to quantitative evaluations. As in the case of other areas in the humanities, the study of the number of women on the boards and as authors has taken second place to analyses of gender positioning in academic careers. Starting from the data entered into Wikidata by the project "Riviste di biblioteconomia" managed by the Wikidata Group for Museums, Archives and Libraries, the contribution presents a focus on AIB Studi, Bibliothecae.it and JLIS.it regarding the gender balance in the scientific committees and board and the number of female contributors. In conclusion, a mention concerns the small number of articles from foreign countries, in particular from Africa and South-East Asia

“La alfabetización: el desafío de un proceso que convoca a todos los niveles educativos”

Reseña del libro de Alicia Acosta “Contextos alfabetizadores. Hablar, leer y escribir en el jardín de infantes, escuela primaria y secundaria”, publicado en el año 2016 por editorial Punto de fuga/19. La obra propone un recorrido crítico sobre el concepto de alfabetización como proceso, poniéndolo en diálogo con la enseñanza en el Nivel inicial, primario y secundario

Decreasing amyloid toxicity through an increased rate of aggregation

Amyloid β is one of the peptides involved in the onset of Alzheimer's disease, yet the structure of the toxic species and its underlying mechanism remain elusive on account of the dynamic nature of the Aβ oligomerisation process. While it has been reported that incubation of Amyloid β (1-42) sequences (Aβ42) lead to formation of aggregates that vary in morphology and toxicity, we demonstrate that addition of a discrete macrocyclic host molecule, cucurbit[8]uril (CB[8]), substantially reduces toxicity in the neuronal cell line SH-SY5Y. The macrocycle preferentially targets Phe residues in Aβ42 complexing them in a 2 : 1 fashion in neighboring peptide strands. A small but significant structural 'switch' occurs, which induces an increased aggregation rate, suggesting a different cell-uptake mechanism for Aβ42 in the presence of CB[8]. Dramatically increasing the rate of Aβ42 aggregation with CB[8] bypasses the toxic, oligomeric state offering an alternative approach to counter Alzheimer's disease.The authors are grateful for funding from an ERC Starting Investigator grant ASPiRe (No. 240629) and an EPSRC Programme grant SNaP (EP/G060649/1)

Porphyrin-based homogeneous catalysts for the CO 2 cycloaddition to epoxides and aziridines

The direct insertion of carbon dioxide (CO2) into three-membered rings, such as epoxides and aziridines, represents a relevant strategy to obtain cyclic carbonates and oxazolidinones, which are two useful classes of fine chemicals. The synthesis of these compounds can be efficiently catalyzed by a combination of metal porphyrin complexes and various co-catalysts in homogeneous systems. The catalytic efficiency of these systems is discussed herein by taking into account both the characteristics of the metals and the nature of the co-catalysts, either when used as two-component systems or when combined in bifunctional catalysts. Moreover, mechanistic proposals of the CO2 cycloaddition processes are reported to provide a rationale of catalytic cycles in order to pave the way for designing more active and efficient catalytic procedures

La conversación literaria como oportunidad para formar lectores que construyan sentidos

Reseña teórica en perspectiva (sección Mapoteca) del libro de Aidan Chambers Dime. Los niños, la lectura y la conversación, publicado en el año 2007 por Fondo de Cultura Económica, en su colección Espacios para la Lectura. La obra propone el enfoque “Dime” el cual se centra en la conversación literaria como posibilidad de que los niños aprendan y tengan la posibilidad de hablar bien de los libros que leen en la escuela.  

Le biblioteche degli ordini professionali: il caso genovese

L’analisi delle biblioteche ordinistiche genovesi offre l’opportunità per ricentrare l’attenzione nei confronti delle biblioteche specializzate private. Le collezioni librarie degli ordini professionali sono costituite da patrimoni bibliografici spesso sottovalutati e/o non sfruttati che, nella maggior parte dei casi genovesi, sono andati dispersi. Il contributo fa emergere le criticità di una gestione non professionalizzata e poco consapevole del valore rappresentato dai materiali documentari di specifico indirizzo sedimentatisi nel tempo. Al contempo, si valutano le potenzialità che simili raccolte librarie potrebbero esprimere nelle reti documentarie locali e nazionali