Beam quality changes in Hermite-Gauss mode fields propagating through Gaussian apertures

The beam quality behavior of Hermite-Gauss laser modes propagating through Gaussian apertures is analyzed

Mechanical Identities of RNA and DNA Double Helices Unveiled at the Single-Molecule Level

[EN] Double-stranded (ds) RNA is the genetic material of a variety of viruses and has been recently recognized as a relevant molecule in cells for its regulatory role. Despite that the elastic response of dsDNA has been thoroughly characterized in recent years in single-molecule stretching experiments, an equivalent study with dsRNA is still lacking. Here, we have engineered long dsRNA molecules for their individual characterization contrasting information with dsDNA molecules of the same sequence. It is known that dsRNA is an A-form molecule unlike dsDNA, which exhibits B-form in physiological conditions. These structural types are distinguished at the single-molecule level with atomic force microscopy (AFM) and are the basis to understand their different elastic response. Force¿extension curves of dsRNA with optical and magnetic tweezers manifest two main regimes of elasticity, an entropic regime whose end is marked by the A-form contour- length and an intrinsic regime that ends in a low-cooperative overstretching transition in which the molecule extends to 1.7 times its A-form contour-length. DsRNA does not switch between the A and B conformations in the presence of force. Finally, dsRNA presents both a lower stretch modulus and overstretching transition force than dsDNA, whereas the electrostatic and intrinsic contributions to the persistence length are larger.This work was supported by grants from the Spanish Ministry of Science and Innovation (BFU2011-29038 and BFU2010-15703) and the Comunidad de Madrid (S2009/MAT/1507). IRA.-G. acknowledges a Ramon y Cajal contract from the Spanish Ministry of Science and Innovation (RYC-2007-01765). Work in the F.M.-H. laboratory was supported by a Starting Grant from the European Research Council (no. 206117) and a grant from the Spanish Ministry of Science and Innovation (FIS2011-24638). We thank M. S. Dillingham for kindly providing the pSP73-JY0 plasmid, M. Menendez for access to a spectropolarimeter, A. Monserrate for polylysine-AFM control experiments, and B. Ibarra for fruitful discussions.Herrero-Galán, E.; Fuentes-Perez. M.E.; Carrasco, C.; Valpuesta, J.; Carrascosa, J.; Moreno-Herrero, F.; Arias-Gonzalez, JR. (2013). Mechanical Identities of RNA and DNA Double Helices Unveiled at the Single-Molecule Level. Journal of the American Chemical Society. 135(1):122-131. https://doi.org/10.1021/ja3054755S122131135

Deriving the Dynamical Masses of Ultra-Luminous X-ray Sources with OSIRIS

Ultra Luminous X-ray Sources (ULXs) are extragalactic X-ray point sources with LX ∼ 1039 − 1041 erg s−1 discovered in the 80s with the Einstein satellite and confirmed as black hole X-ray binaries during the last decade. The nature of the compact object is highly controversial. They could be super-Eddington stellar-mass black holes or intermediate mass black holes. Deriving dynamical masses of the brightest ULXs, which can be done with OSIRIS, is the only way to find out the nature of the compact object.Las ULXs (del acrónimo inglés Ultra Luminous X-ray sources) son fuentes de rayos X puntuales extragalácticas con LX ∼ 1039−1041 erg s−1 descubiertas en los 80 con el satélite Einstein. En la última década se ha confirmado que son binarias de rayos X con agujero negro. Hay mucha controversia sobre la naturaleza del objeto compacto. Podría tratarse de un agujero negro de masa estelar acretando en el régimen super-Eddington, o un agujero negro de masa intermedia. El único método para poder dilucidar la naturaleza de dichos objetos es mediante la determinación de las masas dinámicas de estos sistemas, tarea que se puede realizar con OSIRIS

Optimización energética de un secadero industrial

El objetivo del presente Proyecto Final de Carrera es la optimización energética de un secadero industrial para el secado y tostado de avellanas, reduciendo al mínimo su consumo energético sin alterar las características finales del producto. La primera parte consiste en una revisión de la bibliografía del secado de sólidos y artículos científicos del secado y tostado de alimentos. Se realiza un estudio de la fenomenología del secado, mediante la realización de los balances de energía y materia y el estudio de la cinética de los fenómenos de transporte de calor y materia. Mediante este estudio se obtiene un sistema de ecuaciones y un algoritmo de cálculo que controla la evolución de las variables termodinámicas durante el proceso. El algoritmo se resuelve en el programa Engeeniering Equation Solver (EES) y se aplica al caso concreto de las avellanas. En segundo lugar, se utiliza el programa diseñado para realizar un estudio paramétrico de las variables termodinámicas que influyen en el proceso y un estudio de la influencia de las dimensiones del secadero en dichas variables. Mediante este estudio se obtienen los valores óptimos de las variables termodinámicas, maximizando la eficiencia energética del secadero. Se analiza el comportamiento de las avellanas y el aire durante el proceso para los valores óptimos. Finalmente, se propone como medida de ahorro energética la instalación de un intercambiador. Se diseña el intercambiador mediante el método NTU-Ɛ y su implementación en el programa EES y se estudia su rentabilidad económica

Calorimetric scrutiny of lipid binding by sticholysin II toxin mutants

The mechanisms by which pore-forming toxins are able to insert into lipid membranes are a subject of the highest interest in the field of lipid–protein interaction. Eight mutants affecting different regions of sticholysin II, a member of the pore-forming actinoporin family, have been produced, and their hemolytic and lipid-binding properties were compared to those of the wild-type protein. A thermodynamic approach to the mechanism of pore formation is also presented. Isothermal titration calorimetry experiments show that pore formation by sticholysin II is an enthalpy-driven process that occurs with a high affinity constant (1.7×108 M−1). Results suggest that conformational flexibility at the N-terminus of the protein does not provide higher affinity for the membrane, although it is necessary for correct pore formation. Membrane binding is achieved through two separate mechanisms, that is, recognition of the lipid–water interface by a cluster of aromatic residues and additional specific interactions that include a phosphocholinebinding site. Thermodynamic parameters derived from titration experiments are discussed in terms of a putative model for pore formation

Protein Thermodynamic Destabilization in the Assessment of Pathogenicity of a Variant of Uncertain Significance in Cardiac Myosin Binding Protein C.

In the era of next generation sequencing (NGS), genetic testing for inherited disorders identifies an ever-increasing number of variants whose pathogenicity remains unclear. These variants of uncertain significance (VUS) limit the reach of genetic testing in clinical practice. The VUS for hypertrophic cardiomyopathy (HCM), the most common familial heart disease, constitute over 60% of entries for missense variants shown in ClinVar database. We have studied a novel VUS (c.1809T>G-p.I603M) in the most frequently mutated gene in HCM, MYBPC3, which codes for cardiac myosin-binding protein C (cMyBPC). Our determinations of pathogenicity integrate bioinformatics evaluation and functional studies of RNA splicing and protein thermodynamic stability. In silico prediction and mRNA analysis indicated no alteration of RNA splicing induced by the variant. At the protein level, the p.I603M mutation maps to the C4 domain of cMyBPC. Although the mutation does not perturb much the overall structure of the C4 domain, the stability of C4 I603M is severely compromised as detected by circular dichroism and differential scanning calorimetry experiments. Taking into account the highly destabilizing effect of the mutation in the structure of C4, we propose reclassification of variant p.I603M as likely pathogenic. Looking into the future, the workflow described here can be used to refine the assignment of pathogenicity of variants of uncertain significance in MYBPC3.J.A.C. was funded by the Ministerio de Ciencia, Innovación y Universidades (MCNU) through grants BIO2017-83640-P (AEI/FEDER, UE) and RYC-2014-16604, the European Research Area Network on Cardiovascular Diseases (ERA-CVD/ISCIII, MINOTAUR, AC16/00045), the Comunidad de Madrid (P2018/NMT-4443) and the CNIC-Severo Ochoa intramural grant program (03-2016 IGP). The CNIC is supported by the Instituto de Salud Carlos III (ISCIII), MCNU and the Pro CNIC Foundation, and is a Severo Ochoa Center of Excellence (SEV-2015-0505). G.F. was funded by the Ministero dell’Istruzione, dell’Università e della Ricerca-Rome PS35-126/IND.S

La discapacidad intelectual en el medio penitenciario

Actualmente, la discapacidad intelectual es una realidad que se encuentra en los centros penitenciarios, en concreto, y en el que nos centramos en este trabajo, en el centro penitenciario de Zuera. Este colectivo es desconocido por el resto de la sociedad, ya que, no existe una intervención individual adaptada a sus necesidades, ni un módulo específico para estos internos. Es gracias a la colaboración con Plena Inclusión Aragón que se realiza un trabajo de apoyo a estos internos

Structure prediction of honey bee vitellogenin: a multi-domain protein important for insect immunity

Vitellogenin (Vg) has been implicated as a central protein in the immunity of egg-laying animals. Studies on a diverse set of species suggest that Vg supports health and longevity through binding to pathogens. Specific studies of honey bees (Apis mellifera) further indicate that the vitellogenin (vg) gene undergoes selection driven by local pathogen pressures. Determining the complete 3D structure of full-length Vg (flVg) protein will provide insights regarding the structure–function relationships underlying allelic variation. Honey bee Vg has been described in terms of function, and two subdomains have been structurally described, while information about the other domains is lacking. Here, we present a structure prediction, restrained by experimental data, of flVg from honey bees. To achieve this, we performed homology modeling and used AlphaFold before using a negative-stain electron microscopy map to restrict, orient, and validate our 3D model. Our approach identified a highly conserved Ca2+-ion-binding site in a von Willebrand factor domain that might be central to Vg function. Thereafter, we used rigid-body fitting to predict the relative position of high-resolution domains in a flVg model. This mapping represents the first experimentally validated full-length protein model of a Vg protein and is thus relevant for understanding Vg in numerous species. Our results are also specifically relevant to honey bee health, which is a topic of global concern due to rapidly declining pollinator numbers.publishedVersio

Parametric characterization of general partially coherent beams propagating through ABCD optical-systems

Within the formalism of the Wigner distribution function, a new parameter is proposed, which characterizes arbitrary tridimensional partially coherent beams and is invariant through ABCD optical systems. The relationship between such a parameter and the bidimensional concept of beam quality is analyzed. An absolute lower bound that the new parameter can reach is also shown