VIP-2 —High-Sensitivity Tests on the Pauli Exclusion Principle for Electrons

The VIP collaboration is performing high sensitivity tests of the Pauli Exclusion Principle for electrons in the extremely low cosmic background environment of the underground Gran Sasso National Laboratory INFN (Italy). In particular, the VIP-2 Open Systems experiment was conceived to put strong constraints on those Pauli Exclusion Principle violation models which respect the so-called Messiah–Greenberg superselection rule. The experimental technique consists of introducing a direct current in a copper conductor, and searching for the X-rays emission coming from a forbidden atomic transition from the L shell to the K shell of copper when the K shell is already occupied by two electrons. The analysis of the first three months of collected data (in 2018) is presented. The obtained result represents the best bound on the Pauli Exclusion Principle violation probability which fulfills the Messiah–Greenberg rule.     

Counterion effects on the 183W NMR spectra of the lacunary Keggin polyoxotungstate [PW11O39]7–. Relativistic DFT calculations

The ¹⁸³W NMR spectra of the lacunary Keggin polyoxotungstate [PW₁₁O₃₉]^7– feature noticeable differences according to the counterion (Li or Na). Such differences are modeled by ion pairs where the lacuna is occupied by a Li(H₂O)⁺ or Na(H₂O)⁺ group through relativistic DFT calculation of the tungsten chemical shifts.     

One‐pot,solvent‐free,metal‐free synthesis and UCST‐based purification of poly(ethylene oxide)/poly‐ε‐caprolactone block copolymers

A fast, one pot, solvent‐free and metal‐free synthesis of poly‐ε‐caprolactone and poly(ethylene oxide) block copolymers is reported. Copolymers with different molar mass, different hydrophilic to lipophilic balance, high degree of conversion and narrow molar mass dispersity have been obtained by organocatalyzed ring opening polymerization of ε‐caprolactone in presence of mono‐ or diol‐poly(ethylene oxide) as initiator and fumaric acid as catalyst. A new biocompatible and environmental friendly purification method is presented, exploiting the upper critical solution temperature of these class of copolymers in ethanol. The phase diagrams of the synthesized copolymers in ethanol are also reported. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 2992–2999     

Synthesis and characterization of poly(2,5‐furan dicarboxylate)s based on a variety of diols

Novel polyesters from renewable resources based on 2,5‐dicarboxylic acid and several diols were synthesized and characterized using different polycondensation techniques. The aliphatic diols were sufficiently volatile to allow the use of polytransesterifications, which gave high‐molecular weight semicrystalline materials with good thermal stability. In particular, the polyester based on ethylene glycol displayed properties comparable with those of its aromatic counterpart, poly(ethylene terephthalate), namely, the most important industrial polyester. The use of isosorbide gave rise to amorphous polymers with very stiff chains and hence a high glass transition temperature and an enhanced thermal stability. The interfacial polycondensation between the acid dichloride and hydroquinone produced a semicrystalline material with features similar to those of entirely aromatic polyesters, characterized essentially by the absence of melting and poor solubility, both associated with their remarkable chain rigidity. The replacement of hydroquinone with the corresponding benzylic diol was sufficient to provide a more tractable polyester. This study provided ample evidence in favor of the exploitation of furan monomers as renewable alternatives to fossil‐based aromatic homologs. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Structural informatics,modeling, and design with an open‐source Molecular Software Library (MSL)

We present the Molecular Software Library (MSL), a C++ library for molecular modeling. MSL is a set of tools that supports a large variety of algorithms for the design, modeling, and analysis of macromolecules. Among the main features supported by the library are methods for applying geometric transformations and alignments, the implementation of a rich set of energy functions, side chain optimization, backbone manipulation, calculation of solvent accessible surface area, and other tools. MSL has a number of unique features, such as the ability of storing alternative atomic coordinates (for modeling) and multiple amino acid identities at the same backbone position (for design). It has a straightforward mechanism for extending its energy functions and can work with any type of molecules. Although the code base is large, MSL was created with ease of developing in mind. It allows the rapid implementation of simple tasks while fully supporting the creation of complex applications. Some of the potentialities of the software are demonstrated here with examples that show how to program complex and essential modeling tasks with few lines of code. MSL is an ongoing and evolving project, with new features and improvements being introduced regularly, but it is mature and suitable for production and has been used in numerous protein modeling and design projects. MSL is open‐source software, freely downloadable at http://msl‐libraries.org . We propose it as a common platform for the development of new molecular algorithms and to promote the distribution, sharing, and reutilization of computational methods. © 2012 Wiley Periodicals, Inc.     

An «ultimate» approach to cumulative seismic damage

Summary This paper presents an approach to investigate seismic reliability of structures acted on by more earthquakes.The opportunity to analyze the behaviour of structures under the decisive quake is stressed, and the possibility to derive safety statements by inspecting the way the structure collapses is proved with regard to a simple structural pattern.Numerical results show that the criterion yields results quite consistent with usual practice, though, usually, cumulation of damage is not explicitly accounted for in aseismic standards.

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Sommario Nel presente articolo si espone un possibile metodo per studiare la sicurezza di organismi strutturali esposti all'azione di più terremoti susseguenti.Viene sottolineata l'opportunità di analizzare il comportamento della struttura sotto il terremoto decisivo, e si dimostra con un esempio la possibilità di calcolarne l'affidabilità mediante l'indagine del modo di collasso.I risultati numerici mostrano che questo criterio fornisce, almeno nel semplice caso esaminato, conclusioni coerenti non la pratica tecnica, benché di solito le Norme antisismiche non tengano conto esplicitamente del fenomeno della accumulazione del danno.

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This research has been financially supported by the Italian National Research Council (C.N.R.).