Methicillin-Susceptible Staphylococcus aureus Biofilm Formation on Vascular Grafts: an In Vitro Study

Staphylococcus aureus; Biofilm; InfectionStaphylococcus aureus; Biopelícula; InfecciónStaphylococcus aureus; Biopel·lícula; InfeccióThe aim of this study was to quantify in vitro biofilm formation by methicillin-susceptible Staphylococcus aureus (MSSA) on the surfaces of different types of commonly used vascular grafts. We performed an in vitro study with two clinical strains of MSSA (MSSA2 and MSSA6) and nine vascular grafts: Dacron (Hemagard), Dacron-heparin (Intergard heparin), Dacron-silver (Intergard Silver), Dacron-silver-triclosan (Intergard Synergy), Dacron-gelatin (Gelsoft Plus), Dacron plus polytetrafluoroethylene (Fusion), polytetrafluoroethylene (Propaten; Gore), Omniflow II, and bovine pericardium (XenoSure). Biofilm formation was induced in two phases: an initial 90-minute adherence phase and a 24-hour growth phase. Quantitative cultures were performed, and the results were expressed as log10 CFU per milliliter. The Dacron-silver-triclosan graft and Omniflow II were associated with the least biofilm formation by both MSSA2 and MSSA6. MSSA2 did not form a biofilm on the Dacron-silver-triclosan graft (0 CFU/mL), and the mean count on the Omniflow II graft was 3.89 CFU/mL (standard deviation [SD] 2.10). The mean count for the other grafts was 7.01 CFU/mL (SD 0.82). MSSA6 formed a biofilm on both grafts, with 2.42 CFU/mL (SD 2.44) on the Dacron-silver-triclosan graft and 3.62 CFU/mL (SD 2.21) on the Omniflow II. The mean biofilm growth on the remaining grafts was 7.33 CFU/mL (SD 0.28). The differences in biofilm formation on the Dacron-silver-triclosan and Omniflow II grafts compared to the other tested grafts were statistically significant. Our findings suggest that of the vascular grafts we studied, the Dacron-silver-triclosan and Omniflow II grafts might prevent biofilm formation by MSSA. Although further studies are needed, these grafts seem to be good candidates for clinical use in vascular surgeries at high risk of infections due to this microorganism. IMPORTANCE The Dacron silver-triclosan and Omniflow II vascular grafts showed the greatest resistance to in vitro methicillin-susceptible Staphylococcus aureus biofilm formation compared to other vascular grafts. These findings could allow us to choose the most resistant to infection prosthetic graft

Geometrically controlled ratchet effect with collective vortex motion

© 2015 IOP Publishing Ltd and Deutsche Physikalische Gesellschaft. Rectified flux motion arising from the collective effect of many interacting vortices is obtained in a specially designed superconducting device. Ratchet structures with different asymmetric pinning potentials are generated by tuning the size, depth, and distribution of triangular blind-antidots in a high-temperature superconducting film. We experimentally and theoretically demonstrate that the amplitude and sign of the rectified vortex motion can be finely tuned with the pattern geometry. Two different dynamical regimes depending on the nature of vortices initiating the dissipation are identified, which can control the rectified vortex motion.This work has been supported by MINECO(MAT2014-51778-C2-1R, MAT2012-35370, CSD2007-0041, IPT- 2011-1090-920000), Generalitat de Catalunya (SGR2014-00753, 2014SGR150, XaRMAE), EU-FP7 NMP-LA- 2012-280432 EUROTAPES project and Cost Action MP1201.VR acknowledges the JAE-CSIC PhD grant. AS acknowledges funding from an ICREA Academia award.Peer Reviewe

Tidal Interaction between the UX Tauri A/C Disk System Revealed by ALMA

We present sensitive and high angular-resolution (∼0.″2-0.″3) (sub)millimeter (230 and 345 GHz) continuum and CO(2-1)/CO(3-2) line archive observations of the disk star system in UX Tauri carried out with the Atacama Large Millimeter/Submillimeter Array. These observations reveal the gas and dusty disk surrounding the young star UX Tauri A with a large signal-to-noise ratio (>400 in the continuum and >50 in the line), and for the first time we detect the molecular gas emission associated with the disk of UX Tauri C (with a size for the disk of <56 au). No (sub)millimeter continuum emission is detected at the 5σ level (0.2 mJy at 0.85 mm) associated with UX Tauri C. For the component UX Tauri C, we estimate a dust disk mass of ≤0.05 M ⊕. Additionally, we report a strong tidal disk interaction between both disks, UX Tauri A/C, separated 360 au in projected distance. The CO line observations reveal marked spiral arms in the disk of UX Tauri A and an extended redshifted stream of gas associated with the UX Tauri C disk. No spiral arms are observed in the dust continuum emission of UX Tauri A. Assuming a Keplerian rotation we estimate the enclosed masses (disk+star) from their radial velocities in 1.4 ± 0.6 M o˙ for UX Tauri A, and 70 ± 30/sin i Jupiter masses for UX Tauri C (the latter coincides with the mass upper limit value for a brown dwarf). The observational evidence presented here lead us to propose that UX Tauri C has a close approach of a possible wide, evolving, and eccentric orbit around the disk of UX Tauri A, causing the formation of spiral arms and a stream of molecular gas falling toward UX Tauri C.Fil: Zapata, Luis A.. Instituto de Radioastronomía y Astrofísica; MéxicoFil: Rodríguez, Luis F.. Instituto de Radioastronomía y Astrofísica; México. Universidad Autónoma de Chiapas; MéxicoFil: Fernandez Lopez, Manuel. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Palau, Aina. Instituto de Radioastronomía y Astrofísica; MéxicoFil: Estalella, Robert. Universidad de Barcelona; EspañaFil: Osorio, Mayra. Instituto de Astrofísica de Andalucía; EspañaFil: Anglada, Guillem. Instituto de Astrofísica de Andalucía; EspañaFil: Huelamo, Nuria. Centro de Astrobiología (csic-inta); Españ

Analysis of Mathematical Models Produced when Solving Fermi Problems

[EN] In this paper, we present an analysis of written productions of 16 year-old students while solving Estimation Problems involving Big Numbers (EPiBN). This kind of problems is a particular type of Fermi problems and allows us to introduce modelling processes in Secondary school classrooms. Our analysis supports on the characterization of mathematical models developed by students based on the model definition of Lesh and Harel. The results show that, through the analysis of EPiBN resolutions, differentiating aspects can be distinguished between the models produced by students without modelling experience of those produced by students with prior experience, especially in the concepts and language used to shape the built mathematical models.[ES] En este trabajo presentamos un estudio en el que analizamos las producciones escritas de estudiantes de 16 años con diferentes niveles de experiencia en modelización al resolver Problemas de Estimación de Grandes Cantidades (PEGC). Estos problemas son un tipo concreto de los Problemas de Fermi y permiten introducir los procesos de modelización en las aulas de Educación Secundaria. Nuestro análisis se soporta en la caracterización de los modelos matemáticos que producen los alumnos, basada en la definición de modelo matemático propuesta por Lesh y Harel. Los resultados muestran que, a través del análisis de las resoluciones de PEGC, se pueden distinguir aspectos diferenciadores entre los modelos producidos por alumnos sin experiencia modelizadora de aquellos producidos por alumnos con experiencia previa, especialmente en los conceptos y lenguajes utilizados para dar forma a los modelos matemáticos construidos.Este trabajo es fruto de una investigación llevada a cabo en el marco de los proyectos de investigación EDU2012-35638 y EDU2013-4683-R que han recibido soporte económico del Ministerio de Economía y Competitividad español y de los Fondos FEDER, así como de la ayuda recibida por parte de la Conselleria de Educació de la Generalitat Valenciana (proyecto GV/2016/129) y la Direcció General de Recerca de la Generalitat de Catalunya (SGR2014-723).Ferrando Palomares, I.; Albarracín, L.; Gallart-Palau, C.; García-Raffi, LM.; Gorgorió, N. (2017). Análisis de los Modelos Matemáticos Producidos durante la Resolución de Problemas de Fermi. Bolema. 31(57):220-242. https://doi.org/10.1590/1980-4415v31n57a11S2202423157Albarracín, L., & Gorgorió, N. (2013). PROBLEMAS DE ESTIMACIÓN DE GRANDES CANTIDADES: MODELIZACIÓN E INFLUENCIA DEL CONTEXTO. Revista Latinoamericana de Investigación en Matemática Educativa, 16(3), 289-315. doi:10.12802/relime.13.1631Albarracín, L., & Gorgorió, N. (2014). Devising a plan to solve Fermi problems involving large numbers. Educational Studies in Mathematics, 86(1), 79-96. doi:10.1007/s10649-013-9528-9Blum, W. (2002). Educational Studies in Mathematics, 51(1/2), 149-171. doi:10.1023/a:1022435827400Ferri, R. B. (2006). Theoretical and empirical differentiations of phases in the modelling process. ZDM, 38(2), 86-95. doi:10.1007/bf02655883Carlson, J. E. (1997). Fermi problems on gasoline consumption. The Physics Teacher, 35(5), 308-309. doi:10.1119/1.2344696Efthimiou, C. J., & Llewellyn, R. A. (2007). Cinema, Fermi problems and general education. Physics Education, 42(3), 253-261. doi:10.1088/0031-9120/42/3/003Lesh, R., & Harel, G. (2003). Problem Solving, Modeling, and Local Conceptual Development. Mathematical Thinking and Learning, 5(2), 157-189. doi:10.1207/s15327833mtl0502&3_03Lester, F. K. (1994). Musings about Mathematical Problem-Solving Research: 1970-1994. Journal for Research in Mathematics Education, 25(6), 660. doi:10.2307/749578Schoenfeld, A. H. (2007). Problem solving in the United States, 1970–2008: research and theory, practice and politics. ZDM, 39(5-6), 537-551. doi:10.1007/s11858-007-0038-zCampos, I. da S., & Araújo, J. de L. (2015). Envolvimento dos Alunos em Atividades de Modelagem Matemática: relação com o saber e possibilidades de ação. Bolema: Boletim de Educação Matemática, 29(51), 167-182. doi:10.1590/1980-4415v29n51a09Sriraman, B., & Knott, L. (2009). The Mathematics of Estimation: Possibilities for Interdisciplinary Pedagogy and Social Consciousness. Interchange, 40(2), 205-223. doi:10.1007/s10780-009-9090-

Vocal cord paresis and diaphragmatic dysfunction are severe and frequent symptoms of GDAP1-associated neuropathy

[EN] Cranial nerve involvement in Charcot-Marie-Tooth disease (CMT) is rare, though there are a number of CMT syndromes in which vocal cord paralysis is a characteristic feature. CMT disease due to mutations in the ganglioside-induced differentiation-associated protein 1 gene (GDAP1) has been reported to be associated with vocal cord and diaphragmatic palsy. In order to address the prevalence of these complications in patients with GDAP1 mutations we evaluated vocal cord and respiratory function in nine patients from eight unrelated families with this disorder. Hoarseness of the voice and inability to speak loudly were reported by eight patients and one had associated symptoms of respiratory insufficiency. Patients were investigated by means of peripheral and phrenic nerve conduction studies, flexible laryngoscopy, pulmonary function studies and polysomnography. Nerve conduction velocities and pathological studies were compatible with axonal CMT (CMT2). Flexible laryngoscopy showed left vocal cord palsy in four cases, bilateral cord palsies in four cases and was normal in one case. Restrictive respiratory dysfunction was seen in the eight patients with vocal cord paresis who were all chair-bound. These eight had confirmed phrenic nerve dysfunction on neurophysiology evaluation. The patient with normal vocal cord and pulmonary function had a less severe clinical course.This study shows that CMT patients with GDAP1 mutations develop severe disability due to weakness of limb muscles and that laryngeal and respiratory muscle involvement occurs late in the disease process when significant proximal upper limb weakness has developed. The early and predominant involvement of the left vocal cord innervated by the longer left recurrent laryngeal nerve suggests a length dependent pattern of nerve degeneration. In GDAP1 neuropathy, respiratory function should be thoroughly investigated because life expectancy can be compromised due to respiratory failure.Fondo de Investigacion Sanitaria (PI/05/1572); CIBERNED; CIBERER; Instituto de Salud Carlos III.Sevilla, T.; Jaijo, T.; Nauffal, D.; Collado, D.; Chumillas, MJ.; Vilchez, JJ.; Muelas, N.... (2008). Vocal cord paresis and diaphragmatic dysfunction are severe and frequent symptoms of GDAP1-associated neuropathy. Brain. 131:3051-3061. https://doi.org/10.1093/brain/awn2283051306113

Phenotypical features of the p.R120W mutation in the GDAP1 gene causing autosomal dominant Charcot-Marie-Tooth disease

[EN] Mutations in the ganglioside-induced-differentiation-associated protein 1 gene (GDAP1) can cause Charcot-Marie-Tooth (CMT) disease with demyelinating (CMT4A) or axonal forms (CMT2K and ARCMT2K). Most of these mutations present a recessive inheritance, but few autosomal dominant GDAP1 mutations have also been reported. We performed a GDAP1 gene screening in a clinically well-characterized series of 81 index cases with axonal CMT neuropathy, identifying 17 patients belonging to 4 unrelated families in whom the heterozygous p.R120W was found to be the only disease-causing mutation. The main objective was to fully characterize the neuropathy caused by this mutation. The clinical picture included a mild-moderate phenotype with onset around adolescence, but great variability. Consistently, ankle dorsiflexion and plantar flexion were impaired to a similar degree. Nerve conduction studies revealed an axonal neuropathy. Muscle magnetic resonance imaging studies demonstrated selective involvement of intrinsic foot muscles in all patients and a uniform pattern of fatty infiltration in the calf, with distal and superficial posterior predominance. Pathological abnormalities included depletion of myelinated fibers, regenerative clusters and features of axonal degeneration with mitochondrial aggregates. Our findings highlight the relevance of dominantly transmitted p.R120W GDAP1 gene mutations which can cause an axonal CMT with a wide clinical profile.We are grateful to the propositi and their relatives for their kind collaboration. We also want to thank I. Llopis and M. Escutia for their help with sample management. This work was supported by the Instituto de Salud Carlos III [PI08/90857, PI08/0889, CP08/00053 and PS09/00095], the Fundacion para la Investigacion del Hospital Universitari La Fe [CM06/00154], the Spanish Ministry Science and Innovation [grant number SAF2006-01047], and the Generalitat Valenciana [grant no. Prometeo/2009/05]. Dr. C. Espinos has a "Miguel Servet'' contract funded by the Fondo de Investigacion Sanitaria. Both Centro de Investigacion Biomedica en Red de Enfermedades Raras (CIBERER) and Centro de Investigacion Biomedica en Red de Enfermedades Neurodegenerativas (CIBERNED) are initiatives from the Instituto de Salud Carlos III.Sivera, R.; Espinós-Armero, CÁ.; Vílchez, JJ.; Mas, F.; Martínez-Rubio, D.; Chumillas, MJ.; Mayordomo, F.... (2010). Phenotypical features of the p.R120W mutation in the GDAP1 gene causing autosomal dominant Charcot-Marie-Tooth disease. Journal of the Peripheral Nervous System. 15(4):334-344. https://doi.org/10.1111/j.1529-8027.2010.00286.x33434415

Targeted next generation sequencing in patients with inborn errors of metabolism

BACKGROUND: Next-generation sequencing (NGS) technology has allowed the promotion of genetic diagnosis and are becoming increasingly inexpensive and faster. To evaluate the utility of NGS in the clinical field, a targeted genetic panel approach was designed for the diagnosis of a set of inborn errors of metabolism (IEM). The final aim of the study was to compare the findings for the diagnostic yield of NGS in patients who presented with consistent clinical and biochemical suspicion of IEM with those obtained for patients who did not have specific biomarkers. METHODS: The subjects studied (n = 146) were classified into two categories: Group 1 (n = 81), which consisted of patients with clinical and biochemical suspicion of IEM, and Group 2 (n = 65), which consisted of IEM cases with clinical suspicion and unspecific biomarkers. A total of 171 genes were analyzed using a custom targeted panel of genes followed by Sanger validation. RESULTS: Genetic diagnosis was achieved in 50% of patients (73/146). In addition, the diagnostic yield obtained for Group 1 was 78% (63/81), and this rate decreased to 15.4% (10/65) in Group 2 (X2 = 76.171; p < 0.0001). CONCLUSIONS: A rapid and effective genetic diagnosis was achieved in our cohort, particularly the group that had both clinical and biochemical indications for the diagnosis

Competition between superconductor : ferromagnetic stray magnetic fields in YBa2Cu3O7−x films pierced with Co nano-rods

Altres ajuts: Cost Actions MP1201 and CM1301 (CELINA). A. Sanchez acknowledges a grant from ICREA Academia, funded by the Generalitat de Catalunya. We are grateful to I. Rivas and R. Valero from LMA-INA (Zaragoza, Spain) for experimental help in the cobalt growth and Ar+milling processes, and Dr C. Magén and Dr. P. Algarabel from LMA-INA (Zaragoza, Spain) for facilitating the use of their high performance computing server to perform the micromagnetic simulations. We acknowledge R. Morales from UPV/EHU and Ikerbasque, A. Fernández-Pacheco from U. Cambridge and S. Valencia from Helmholtz-Zentrum, Berlin for fruitful discussions.Superconductivity and ferromagnetism are two antagonistic phenomena that combined can lead to a rich phenomenology of interactions, resulting in novel physical properties and unique functionalities. Here we propose an original hybrid system formed by a high-temperature superconducting film, patterned with antidots, and with ferromagnetic nano-rods grown inside them. This particular structure exhibits the synergic influence of superconductor (SC) - ferromagnetic (FM) stray fields, in both the superconducting behaviour of the film and the three-dimensional (3D) magnetic structure of nano-rods. We show that FM stray fields directly influence the critical current density of the superconducting film. Additional functionalities appear due to the interaction of SC stray fields, associated to supercurrent loops, with the non-trivial 3D remanent magnetic structure of FM nano-rods. This work unravels the importance of addressing quantitatively the effect of stray magnetic fields from both, the superconductor and the ferromagnet in hybrid magnetic nano-devices based on high temperature superconductors

A state-of-the-art guide about the effects of sterilization processes on 3D-printed materials for surgical planning and medical applications: a comparative study

Surgeons use different medical devices in the surgery, such as patient-specific anatomical models, cutting and positioning guides, or implants. These devices must be sterilized before being used in the operation room. There are many sterilization processes available, with autoclave, hydrogen peroxide, and ethylene oxide being the most common in hospital settings. Each method has both advantages and disadvantages in terms of mechanics, chemical interaction, and post-treatment accuracy. The aim of the present study is to evaluate the dimensional and mechanical effect of the most commonly used sterilization techniques available in clinical settings, i.e., Autoclave 121, Autoclave 134, and hydrogen peroxide (HPO), on 11 of the most used 3D-printed materials fabricated using additive manufacturing technologies. The results showed that the temperature (depending on the sterilization method) and the exposure time to that temperature influence not only the mechanical behavior but also the original dimensioning planned on the 3D model. Therefore, HPO is a better overall option for most of the materials evaluated. Finally, based on the results of the study, a recommendation guide on sterilization methods per material, technology, and clinical application is presented.The research described in this paper was partially funded by the project named QuirofAM (Exp. COMRDI16-1-0011) and funded by ACCIÓ from the Catalan government and ERDF from European Union.Postprint (published version