Conformations Of A Model Protein Revealed By An Aggregating Cuᴵᴵ Porphyrin: Sensing The Difference

Aggregated t-CuP binds to poly-L-glutamate through supramolecular interactions, revealing itself to be an extremely sensitive probe for the major conformations of the polymeric scaffold

Effect Of Zinc Cations On The Kinetics Of Supramolecular Assembly And The Chirality Of Porphyrin J-Aggregates

Dilute aqueous solutions of anionic meso-4-sulfonatophenyl-porphyrin (TPPS) extract zinc(ii) ions from glass or quartz surfaces at room temperature and efficiently form the corresponding metal complex (ZnTPPS). The partial or complete formation of ZnTPPS has been probed by UV/Vis spectroscopy and both static and time-resolved fluorescence. The source of zinc(ii) ions has been clearly identified through inductively coupled plasma optical emission spectrometry. The presence of increasing amounts of ZnTPPS slows down the rate of TPPS J-aggregate formation in acid solution. This influences the nucleation step and has a profound impact on the onset of chirality in these species. This evidence indicates the important role of this adventitious metal ion in the interpretation of various spectroscopic and kinetic data for the self-assembly of the TPPS porphyrin and provides some insights into controversial findings on their chirality. The use of this metal derivative as the starting compound for in situ formation of monomeric TPPS is suggested

Mechanism For Copper(II)-Mediated Disaggregation Of A Porphyrin J-Aggregate

J-aggregates of anionic meso-tetrakis(4-sulfonatophenyl)porphyrin form at intermediate pH (2.3–3.1) in the presence of NiSO₄ or ZnSO₄ (ionic strength, I.S. = 3.2 M). These aggregates convert to monomeric porphyrin units via metallation with copper(II) ions. The kinetics for the disassembly process, as monitored by UV/vis spectroscopy, exhibits zeroth-order behavior. The observed zeroth-order rate constants show a two-term dependence on copper(II) ion concentrations: linear and second order. Also observed is an inverse dependence on hydrogen ion concentration. Activation parameters have been determined for the disassembly process leading to ΔH^≠ = (+163 ± 15) kJ·mol⁻¹ and ΔS^≠ = (+136 ± 11) J·K⁻¹. A mechanism is proposed in which copper(II) cation is in pre-equilibrium with a reactive site at the rim of the J-aggregate. An intermediate copper species is thus formed that eventually leads to the final metallated porphyrin either through an assisted attack of a second metal ion or through a direct insertion of the metal cation into the macrocycle core

Adhesive and Rheological Features of Ecofriendly Coatings with Antifouling Properties

In this work, formulations of "environmentally compatible" silicone-based antifouling, synthesized in the laboratory and based on copper and silver on silica/titania oxides, have been characterized. These formulations are capable of replacing the non-ecological antifouling paints currently available on the market. The texture properties and the morphological analysis of these powders with an antifouling action indicate that their activity is linked to the nanometric size of the particles and to the homogeneous dispersion of the metal on the substrate. The presence of two metal species on the same support limits the formation of nanometric species and, therefore, the formation of homogeneous compounds. The presence of the antifouling filler, specifically the one based on titania (TiO2) and silver (Ag), facilitates the achievement of a higher degree of cross-linking of the resin, and therefore, a better compactness and completeness of the coating than that attained with the pure resin. Thus, a high degree of adhesion to the tie-coat and, consequently, to the steel support used for the construction of the boats was achieved in the presence of the silver-titania antifouling

Optical and electronic properties of manganese thiophosphate and H2T4 porphyrin metal complexes films

Films of manganese thiophosphate (MnPS3) and Mn(III)T4 porphyrin, obtained from a reaction of a colloidal suspension of MnPS3 nanosheets with an aqueous solution of the porphyrin, have been investigated by means of optical absorption and X-ray photoemission spectroscopies. Our attention is turned to the (300–850) nm range and to the C and N 1s, Mn, P, S and Cl 2p and Mn 3p core regions. The analysis of the resulting spectra and their comparison with those reported for the original compounds has allowed us to obtain information both about the interaction between MnPS3 and Mn(III)T4 and the effects produced by the porphyrin metallation

Best practices and QA protocols for code development

The OperaHPC project aims to improve the numerical capabilities of 3D fuel performance modelling as part of its strategic objectives. To achieve this goal, an open-source approach has been chosen for the tools developed in the framework of the project, namely MMM and OFFBEAT, the latter coupled to the SCIANTIX code. As the open-source approach is relatively new in the domain of nuclear safety studies, this document presents a framework for achieving quality assurance targets for the open-source scientific computing tools within the OperaHPC project. First, the document provides a brief review of the most common QA programs and standards employed in the field, with a particular focus to the aspects that are more relevant to OperaHPC. Then, it discusses modern software development practices to improve code quality, highlighting the importance of revision control systems, testing methodologies, and documentation. Finally, it describes the concept of governance model for regulating interactions between contributors, users, and decision-makers. The framework presented in this document provides a backbone for the verification and validation actions that will be carried out within the project and contributes to the qualification of the MMM, OFFBEAT and SCIANTIX tools for nuclear safety studies

Germano Sartelli

Libro-catalogo della mostra sugli artisti imolesi che hanno partecipato alle Biennali Internazionali d'arte di Venezia. Capitolo dedicato all'opera dello scultore Germano Sartelli, tra i principali esponenti dell'informale italiano