On the possibility of extending the Nore-Frenkel generalized law of correspondent states to non-isotropic patchy interactions

Colloidal systems (and protein solutions) are often characterized by attractive interactions whose range is much smaller than the particle size. When this is the case and the interaction is spherical, systems obey a generalized law of correspondent states (GLCS), first proposed by Noro and Frenkel [ J.Chem.Phys. 113, 2941 (2000) ]. The thermodynamic properties become insensitive to the details of the potential, depending only on the value of the second virial coefficient B_2 and the density $\rho$. The GLCS does not generically hold for the case of non-spherical potentials. In this Letter we suggest that when particles interact via short-ranged small-angular amplitude patchy interactions (so that the condition of only one bond per patch is fulfilled) it is still possible to generalize the GLCS close to the liquid-gas critical point. Keywords: Colloids, Second Virial Coefficient, Proteins interactions, Short-ranged attractive attractions.Comment: 11 pages, 3 figures. Accepted for publication on J. Phys. Chem.

Noro-Frenkel scaling in short-range square well: A Potential Energy Landscape study

We study the statistical properties of the potential energy landscape of a system of particles interacting via a very short-range square-well potential (of depth $-u_0$), as a function of the range of attraction $\Delta$ to provide thermodynamic insights of the Noro and Frenkel [ M.G. Noro and D. Frenkel, J.Chem.Phys. {\bf 113}, 2941 (2000)] scaling. We exactly evaluate the basin free energy and show that it can be separated into a {\it vibrational} ($\Delta$-dependent) and a {\it floppy} ($\Delta$-independent) component. We also show that the partition function is a function of $\Delta e^{\beta u_o}$, explaining the equivalence of the thermodynamics for systems characterized by the same second virial coefficient. An outcome of our approach is the possibility of counting the number of floppy modes (and their entropy).Comment: 4 pages, 4 figures accepted for publication on PR

Nuevas tendencias en las políticas de inmigración italianas: “cambiar algo para que nada cambie”

Este ARI examina los recientes cambios en la política de inmigración italiana llevados a cabo en 2008 por el gobierno conservador de Silvio Berlusconi. Las medidas contra la migración irregular aprobadas en 2008 han suscitado una oleada de críticas en toda la UE. El gobierno italiano de Silvio Berlusconi ha sido acusado de racismo mientras que el ministro de Interior italiano insistía en que solo se trataba de formas razonables de ocuparse de la inmigración irregular y de garantizar la seguridad de los ciudadanos italianos. Este ARI sostiene que las nuevas normas, a pesar de ser más ambiguas de lo que parecen a primera vista (y a veces bastante desagradables), no resuelven la contradicción existente en la política de inmigración italiana, donde existe una demanda creciente de mano de obra extranjera que choca con la tendencia hacia medidas más restrictivas. El principal objeto de este ARI es mostrar que la reforma propuesta por el gobierno italiano difícilmente logrará reducir el flujo de inmigrantes irregulares en Italia

New Trends in Italian Immigration Policies: 'To change everything in order to keep everything the same'

This ARI looks at the recent developments in Italian immigration policies carried out in 2008 by the conservative government of Silvio Berlusconi. The measures against irregular migration approved in 2008 have given rise to a wave of criticism across the EU. The Italian government of Silvio Berlusoni has been accused of racism while the Italian Minister of the Interior insists that his measures are simply reasonable ways of dealing with irregular immigration and guaranteeing the safety of Italian citizens. This paper argues that the new rules, although more uncertain than they seem at first glance (and sometimes thoroughly unpleasant), do not solve the contradictory logic of Italy’s immigration policies, with an increasing demand for foreign labour conflicting with the trend towards more restrictive measures. The main object of this paper is to show that the reform proposed by the Italian government is unlikely to reduce the rate of irregular migrants in Italy

È possibile misurare l’integrazione degli immigrati? Lo stato dell’arte

Da diversi decenni, l’immigrazione è un tema caldo per l’opinione pubblica dei paesi europei (e non). Vi è una diffusa insoddisfazione per la capacità delle politiche adottate di favorire effettivamente l’«integrazione» dei segmenti di popolazione straniera residenti sul territorio. In che misura questa insoddisfazione coglie una difficoltà reale? Per saperlo, bisognerebbe essere in grado di definire con esattezza cosa debba intendersi per «integrazione», come essa andrebbe misurata e, last but not least, come valutare se le politiche messe in atto dai governi occidentali producono o meno gli effetti desiderati. Su ognuno di questi punti, esiste un ricco dibattito scientifico spesso poco conosciuto. In questo lavoro viene condotta una rassegna critica della letteratura scientifica sul tema, volta ad evidenziare le risorse già disponibili e i problemi ancora aperti

DFT Protocol for EPR prediction of paramagnetic Cu(II) complexes and application to protein binding sites

With the aim to provide a general protocol to interpret electron paramagnetic resonance (EPR) spectra of paramagnetic copper(II) coordination compounds, density functional theory (DFT) calculations of spin Hamiltonian parameters g and A for fourteen Cu(II) complexes with different charges, donor sets, and geometry were carried out using ORCA software. The performance of eleven functionals was tested, and on the basis of the mean absolute percent deviation (MAPD) and standard deviation (SD), the ranking of the functionals for Az is: B3LYP > B3PW91 ~ B3P86 > PBE0 > CAM-B3LYP > TPSSh > BH and HLYP > B2PLYP > MPW1PW91 > ω-B97x-D » M06; and for gz is: PBE0 > BH and HLYP > B2PLYP > ω-B97x-D > B3PW91~B3LYP~B3P86 > CAM-B3LYP > TPSSh~MPW1PW91 » M06. With B3LYP the MAPD with respect to A exp tl z is 8.6% with a SD of 4.2%, while with PBE0 the MAPD with respect to g exp tl z is 2.9% with a SD of 1.1%. The results of the validation confirm the fundamental role of the second order spin-orbit contribution to Az. The computational procedure was applied to predict the values of gz and Az of the adducts formed by Cu(II) with albumin and two fragments of prion protein, 106-126 and 180-193

Validation and Applications of Protein-Ligand Docking Approaches Improved for Metalloligands with Multiple Vacant Sites

Altres ajuts: COST Action CM1306Decoding the interaction between coordination compounds and proteins is of fundamental importance in biology, pharmacy, and medicine. In this context, protein-ligand docking represents a particularly interesting asset to predict how small compounds could interact with biomolecules, but to date, very little information is available to adapt these methodologies to metal-containing ligands. Here, we assessed the predictive capability of a metal-compatible parameter set for the docking program GOLD for metalloligands with multiple vacant sites and different geometries. The study first presents a benchmark of 25 well-characterized X-ray metalloligand-protein adducts. In 100% of the cases, the docking solutions are superimposable to the X-ray determination, and in 92% the value of the root-mean-square deviation between the experimental and calculated structures is lower than 1.5 Å. After the validation step, we applied these methods to five case studies for the prediction of the binding of pharmacological active metal species to proteins: (i) the anticancer copper(II) complex [Cu II (Br)(2-hydroxy-1-naphthaldehyde benzoyl hydrazine)(indazole)] to human serum albumin (HSA); (ii) one of the active species of antidiabetic and antitumor vanadium compounds, V IV O 2+ ion, to carboxypeptidase; (iii) the antiarthritic species [Au I (PEt 3 )] + to HSA; (iv) the antitumor oxaliplatin to ubiquitin; (v) the antitumor ruthenium(II) compound RAPTA-PentaOH to cathepsin B. The calculations suggested that the binding modes are in good agreement with the partial information retrieved from spectroscopic and spectrometric analysis and allowed us, in certain cases, to propose additional hypotheses. This method is an important update in protein-metalloligand docking, which could have a wide field of application, from biology and inorganic biochemistry to medicinal chemistry and pharmacology

Sol–Gel Microcapsulation in Silica-Based Particles: A Comparative Study

We compare the two main sol-gel/emulsion methods to prepare silica-based microparticles doped with actives. Moreover, we analyze the morphpology of the resulting particles varying also the nature of the organosilane, and the pH of the sol-gel process. Benzoyl peroxide was used as molecular dopant

On the Impact of Morphisms on BWT-Runs

Morphisms are widely studied combinatorial objects that can be used for generating infinite families of words. In the context of Information theory, injective morphisms are called (variable length) codes. In Data compression, the morphisms, combined with parsing techniques, have been recently used to define new mechanisms to generate repetitive words. Here, we show that the repetitiveness induced by applying a morphism to a word can be captured by a compression scheme based on the Burrows-Wheeler Transform (BWT). In fact, we prove that, differently from other compression-based repetitiveness measures, the measure r_bwt (which counts the number of equal-letter runs produced by applying BWT to a word) strongly depends on the applied morphism. More in detail, we characterize the binary morphisms that preserve the value of r_bwt(w), when applied to any binary word w containing both letters. They are precisely the Sturmian morphisms, which are well-known objects in Combinatorics on words. Moreover, we prove that it is always possible to find a binary morphism that, when applied to any binary word containing both letters, increases the number of BWT-equal letter runs by a given (even) number. In addition, we derive a method for constructing arbitrarily large families of binary words on which BWT produces a given (even) number of new equal-letter runs. Such results are obtained by using a new class of morphisms that we call Thue-Morse-like. Finally, we show that there exist binary morphisms ? for which it is possible to find words w such that the difference r_bwt(?(w))-r_bwt(w) is arbitrarily large

Directed self-assembly of trimeric DNA-bindingchiral miniprotein helicates

We propose that peptides are highly versatile platforms for the precise design of supramolecular metal architectures, and particularly, for the controlled assembly of helicates. In this context, we show that the bacteriophage T4 Fibritin foldon (T4Ff) can been engineered on its N-terminus with metal-chelating 2,2′-bipyridine units that stereoselectively assemble in the presence of Fe(II) into parallel, three-stranded peptide helicates with preferred helical orientation. Modeling studies support the proposed self-assembly and the stability of the final helicate. Furthermore, we show that these designed mini-metalloproteins selectively recognize three-way DNA junctions over double-stranded DNAFinancial support from the Spanish grants CTQ2015-70698-R, CTQ2017-87889-P, the Xunta de Galicia (Centro singular de investigación de Galicia accreditation 2016–2019, ED431G/09) and the European Union (European Regional Development Fund - ERDF), is gratefully acknowledged. JG-G, thanks the Spanish MINECO for his FPI fellowship, GB thanks the ERC for her EU METALIC-II 2013-2442/001-001-EMA2 mobility scheme fellowship, and GS. thanks the Universitat Autònoma de Barcelona for its support to his PhD. J-DM and GS are thankful for the support given by the Generalitat de Catalunya 2017SGR1323. Support of COST Action CM1306 is kindly acknowledged. MEV, also wish to acknowledge the generous support by the Fundación Asociación Española Contra el Cáncer AECC (IDEAS197VAZQ grant)S