Congruences of small degree in G(1,4)

We give the list of all possible congruences in G(1,4) of degree d ≤10 and we explicitely construct most of them.     

Congruences on near-Heyting algebras

A near-Heyting algebra is a join-semilattice with a top element such that every principal upset is a Heyting algebra. We establish a one-to-one correspondence between the lattices of filters and congruences of a near-Heyting algebra. To attain this aim, we first show an embedding from the lattice of filters to the lattice of congruences of a distributive nearlattice. Then, we describe the subdirectly irreducible and simple near-Heyting algebras. Finally, we fully characterize the principal congruences of distributive nearlattices and near-Heyting algebras. We conclude that the varieties of distributive nearlattices and near-Heyting algebras have equationally definable principal congruences.     

Platinum(II)-Based Optical Probes for Imaging Quadruplex DNA Structures via Phosphorescence Lifetime Imaging Microscopy

G-quadruplex DNA is a non-canonical structure that forms in guanine-rich regions of the genome. There is increasing evidence showing that G-quadruplexes have important biological functions, and therefore molecular tools to visualise these structures are important. Herein we report on a series of new cyclometallated platinum(II) complexes which, upon binding to G-quadruplex DNA, display an increase in their phosphorescence, acting as switch-on probes. More importantly, upon binding to G-quadruplexes they display a selective and distinct lengthening of their emission lifetime. We show that this effect can be used to selectively visualise these structures in cells using Phosphorescence Lifetime Imaging Microscopy (PLIM).     

Non-maturing deposits modelling in a Ornstein-Uhlenbeck framework

This paper builds a multivariate Lévy-driven Ornstein-Uhlenbeck process for the management of non-maturing deposits, that are a major source of funding for banks. The contribution of the paper is both theoretical and operational. On the theoretical side, the novelty of this model is to include three independent sources of randomness in a Lévy framework: market interest rates, deposit rates and deposit volumes. The choice of a Lévy background driving process allows us to model rare but severe events. On the operational side, we propose a procedure to include severe volume outflows with positive probability in future scenarios simulation, explaining its implementation with an illustrative example using Italian banking sector data.     

Cacaoidin,First Member of the New Lanthidin RiPP Family

Lantibiotics are ribosomally synthesized and post-translationally modified peptides (RiPPs) characterized by the presence of lanthionine or methyllanthionine rings and their antimicrobial activity. Cacaoidin, a novel glycosylated lantibiotic, was isolated from a Streptomyces cacaoi strain and fully characterized by NMR, mass spectrometry, chemical derivatization approaches and genome analysis. The new molecule combines outstanding structural features, such as a high number of d -amino acids, an uncommon glycosylated tyrosine residue and an unprecedented N,N-dimethyl lanthionine. This latter feature places cacaoidin within a new RiPP family located between lanthipeptides and linaridins, here termed lanthidins. Cacaoidin displayed potent antibacterial activity against Gram-positive pathogens including Clostridium difficile. The biosynthetic gene cluster showed low homology with those of other known lanthipeptides or linaridins, suggesting a new RiPP biosynthetic pathway.     

Food authentication in real life: How to link nontargeted approaches with routine analytics?

In times of increasing globalization and the resulting complexity of trade flows, securing food quality is an increasing challenge. The development of analytical methods for checking the integrity and, thus, the safety of food is one of the central questions for actors from science, politics, and industry. Targeted methods, for the detection of a few selected analytes, still play the most important role in routine analysis. In the past 5 years, nontargeted methods that do not aim at individual analytes but on analyte profiles that are as comprehensive as possible have increasingly come into focus. Instead of investigating individual chemical structures, data patterns are collected, evaluated and, depending on the problem, fed into databases that can be used for further nontargeted approaches. Alternatively, individual markers can be extracted and transferred to targeted methods. Such an approach requires (i) the availability of authentic reference material, (ii) the corresponding high-resolution laboratory infrastructure, and (iii) extensive expertise in processing and storing very large amounts of data. Probably due to the requirements mentioned above, only a few methods have really established themselves in routine analysis. This review article focuses on the establishment of nontargeted methods in routine laboratories. Challenges are summarized and possible solutions are presented.     

Self-Assembly of an Amino Acid Derivative into an Antimicrobial Hydrogel Biomaterial

N-(4-Nitrobenzoyl)-Phe self-assembled into a transparent supramolecular hydrogel, which displayed high fibroblast and keratinocyte cell viability. The compound showed a mild antimicrobial activity against E. coli both as a hydrogel and in solution. Single-crystal XRD data revealed packing details, including protonation of the C-terminus due to an apparent pK_a shift, as confirmed by pH titrations. MicroRaman analysis revealed almost identical features between the gel and crystal states, although more disorder in the former. The hydrogel is thermoreversible and disassembles within a range of temperatures that can be fine-tuned by experimental conditions, such as gelator concentration. At the minimum gelling concentration of 0.63 wt %, the hydrogel disassembles in a physiological temperature range of 39–42 °C, thus opening the way to its potential use as a biomaterial.     

Simple Synthetic Routes to N-Heterocyclic Carbene Gold(I)–Aryl Complexes: Expanded Scope and Reactivity

The discovery of sustainable and scalable synthetic protocols leading to gold–aryl compounds bearing N-heterocyclic carbene (NHC) ligands sparked an investigation of their reactivity and potential utility as organometallic synthons. The use of a mild base and green solvents provide access to these compounds, starting from widely available boronic acids and various [Au(NHC)Cl] complexes, with reactions taking place under air, at room temperature and leading to high yields with unprecedented ease. One compound, (N,N′-bis[2,6-(di-isopropyl)phenyl]imidazol-2-ylidene)(4-methoxyphenyl)gold, ([Au(IPr)(4-MeOC₆H₄)]), was synthesized on a multigram scale and used to gauge the reactivity of this class of compounds towards C−H/N−H bonds and with various acids, revealing simple pathways to gold–based species that possess attractive properties as materials, reagents and/or catalysts.