Wheel–rail contact: experimental study of the creep forces–creepage relationships

The wheel–rail contact problem plays an important role in the simulation methods used to solve railway dynamics problems. As a consequence, many different mathematical models have been developed to calculate wheel–rail contact forces. However, most of them tackle this problem purely from a theoretical point of view and need to be experimentally validated. Such validation could also reveal the influence of certain parameters not taken into account in the mathematical developments. This paper presents the steps followed in building a scaled test-bench to experimentally characterise the wheel–rail contact problem. The results of the longitudinal contact force as a function of the longitudinal creepage are obtained and the divergences with respect to Kalker's simplified theory are analysed. The influence of lateral creepage, angular velocity and certain contaminants such as cutting fluid or high positive friction modifier is also discussed

Herida antebraquial infectada por Aeromonas hydrophila

Se presenta un caso de celulitis por Aeromonas hydrophila, en un paciente de 23 años, tras una herida antebraquial producida en el medio acuático. La celulitis se resolvió mediante desbridamiento agresivo y quimioterapia. En los controles posteriores no se han apreciado déficits funcionales tras la infección.A case of Aeromonas hidrophila cellulitis developped in a 23-year-old patient, after aquatic environment forearm wound is presented. His cellulitis was effectively resolved with aggressive debridement and chemotherapy. Follow-up examinations have shown no residual functional deficits from the infection

A case–control study to assess the effectiveness of pertussis vaccination during pregnancy on newborns, Valencian community, Spain, 1 March 2015 to 29 February 2016

In the Valencian Community (Spain), the programme of maternal pertussis vaccination during pregnancy started in January 2015. The objective of this study was to estimate in this region the vaccine effectiveness (VE) in protecting newborns against laboratory-confirmed pertussis infection. A matched case–control study was undertaken in the period between 1 March 2015 and 29 February 2016. Twenty-two cases and 66 controls (+/− 15 days of age difference) were included in the study. Cases were non-vaccinated infants < 3 months of age at disease onset testing positive for pertussis by real-time PCR. For every case three unvaccinated controls were selected. Odds ratios (OR) were calculated by multiple conditional logistic regression for association between maternal vaccination and infant pertussis. Other children in the household, as well as mother- and environmental covariates were taken into account. The VE was calculated as 1 − OR. Mothers of five cases (23%) and of 41 controls (62%) were vaccinated during pregnancy. The adjusted VE was 90.9% (95% confidence interval (CI): 56.6 to 98.1). The only covariate in the final model was breastfeeding (protective effect). Our study provides evidence in favour of pertussis vaccination programmes for pregnant women in order to prevent whooping cough in infants aged less than 3 months

Technical design and performance of the NEMO3 detector

The development of the NEMO3 detector, which is now running in the Frejus Underground Laboratory (L.S.M. Laboratoire Souterrain de Modane), was begun more than ten years ago. The NEMO3 detector uses a tracking-calorimeter technique in order to investigate double beta decay processes for several isotopes. The technical description of the detector is followed by the presentation of its performance.Comment: Preprint submitted to Nucl. Instrum. Methods A Corresponding author: Corinne Augier ([email protected]

The compositional and evolutionary logic of metabolism

Metabolism displays striking and robust regularities in the forms of modularity and hierarchy, whose composition may be compactly described. This renders metabolic architecture comprehensible as a system, and suggests the order in which layers of that system emerged. Metabolism also serves as the foundation in other hierarchies, at least up to cellular integration including bioenergetics and molecular replication, and trophic ecology. The recapitulation of patterns first seen in metabolism, in these higher levels, suggests metabolism as a source of causation or constraint on many forms of organization in the biosphere. We identify as modules widely reused subsets of chemicals, reactions, or functions, each with a conserved internal structure. At the small molecule substrate level, module boundaries are generally associated with the most complex reaction mechanisms and the most conserved enzymes. Cofactors form a structurally and functionally distinctive control layer over the small-molecule substrate. Complex cofactors are often used at module boundaries of the substrate level, while simpler ones participate in widely used reactions. Cofactor functions thus act as "keys" that incorporate classes of organic reactions within biochemistry. The same modules that organize the compositional diversity of metabolism are argued to have governed long-term evolution. Early evolution of core metabolism, especially carbon-fixation, appears to have required few innovations among a small number of conserved modules, to produce adaptations to simple biogeochemical changes of environment. We demonstrate these features of metabolism at several levels of hierarchy, beginning with the small-molecule substrate and network architecture, continuing with cofactors and key conserved reactions, and culminating in the aggregation of multiple diverse physical and biochemical processes in cells.Comment: 56 pages, 28 figure

The Elusive Third Subunit IIa of the Bacterial B-Type Oxidases: The Enzyme from the Hyperthermophile Aquifex aeolicus

The reduction of molecular oxygen to water is catalyzed by complicated membrane-bound metallo-enzymes containing variable numbers of subunits, called cytochrome c oxidases or quinol oxidases. We previously described the cytochrome c oxidase II from the hyperthermophilic bacterium Aquifex aeolicus as a ba3-type two-subunit (subunits I and II) enzyme and showed that it is included in a supercomplex involved in the sulfide-oxygen respiration pathway. It belongs to the B-family of the heme-copper oxidases, enzymes that are far less studied than the ones from family A. Here, we describe the presence in this enzyme of an additional transmembrane helix “subunit IIa”, which is composed of 41 amino acid residues with a measured molecular mass of 5105 Da. Moreover, we show that subunit II, as expected, is in fact longer than the originally annotated protein (from the genome) and contains a transmembrane domain. Using Aquifex aeolicus genomic sequence analyses, N-terminal sequencing, peptide mass fingerprinting and mass spectrometry analysis on entire subunits, we conclude that the B-type enzyme from this bacterium is a three-subunit complex. It is composed of subunit I (encoded by coxA2) of 59000 Da, subunit II (encoded by coxB2) of 16700 Da and subunit IIa which contain 12, 1 and 1 transmembrane helices respectively. A structural model indicates that the structural organization of the complex strongly resembles that of the ba3 cytochrome c oxidase from the bacterium Thermus thermophilus, the IIa helical subunit being structurally the lacking N-terminal transmembrane helix of subunit II present in the A-type oxidases. Analysis of the genomic context of genes encoding oxidases indicates that this third subunit is present in many of the bacterial oxidases from B-family, enzymes that have been described as two-subunit complexes

Hepatitis A. Una enfermedad transmisible de nuevo en crecimiento en la ciudad de Valencia

La hepatitis A es una enfermedad infecciosa de transmisi&oacute;n fecal-oral producida por el virus de la Hepatitis A. En la mayor&iacute;a de casos se trata de una infecci&oacute;n asintom&aacute;tica pero en ocasiones puede dar lugar a un cuadro grave de hepatitis fulminante.&nbsp;En las &uacute;ltimas d&eacute;cadas la hepatitis A ha sufrido una importante disminuci&oacute;n en Europa y en el mundo. Sin embargo, la disminuci&oacute;n en la exposici&oacute;n al virus de la Hepatitis A (VHA) ha conllevado una disminuci&oacute;n de la proporci&oacute;n de poblaci&oacute;n con inmunidad adquirida.El objetivo del presente trabajo es conocer las caracter&iacute;sticas de los pacientes afectados de hepatitis A y la evoluci&oacute;n de dicha enfermedad durante los a&ntilde;os 2004-2009 en la ciudad de Valencia, as&iacute; como contrastar si esta evoluci&oacute;n se acompa&ntilde;a de un desplazamiento de la Hepatitis A hacia cohortes de edad superiores.Se recuperaron los casos de hepatitis A notificados y registrados en el sistema de An&aacute;lisis de Vigilancia Epidemiol&oacute;gica (AVE) entre 2004 y 2009 en la ciudad de Valencia. Se realiz&oacute; un an&aacute;lisis de la evoluci&oacute;n de la edad en funci&oacute;n del tiempo, el modo de presentaci&oacute;n de los casos, la agregaci&oacute;n temporal, y el ingreso hospitalario como criterio de gravedad, as&iacute; como su relaci&oacute;n con poblaciones infantiles. Los datos han sido tabulados y analizados&nbsp; con el programa SPSS versi&oacute;n 14 para windows.Durante el periodo a estudio se registraron 397 casos de VHA. La incidencia anual ha pasado de 3,56 por cada 100.000 habitantes en 2004 a 11,67 en 2009. El 61% de los casos son hombres y el 39% son mujeres. La media de edad ha pasado de 17,97 en el a&ntilde;o 2004 a 32,25 en el 2009. Respecto de su origen, el 87,1% de los casos era aut&oacute;ctono. El modo de presentaci&oacute;n fue en el 27,7 % de los casos en el contexto de un brote y en el resto no se pudo establecer v&iacute;nculo, por lo que se consideraron casos aislados. La evoluci&oacute;n temporal, muestra agregaciones en las semanas epidemiol&oacute;gicas 41-42, correspondiendo con el final del periodo vacacional.Entre los motivos que pueden explicar el aumento de casos en la ciudad de Valencia podemos se&ntilde;alar la disminuci&oacute;n de la poblaci&oacute;n con inmunidad adquirida como efecto de la mejora en las condiciones del abastecimiento h&iacute;drico. Esta hip&oacute;tesis ser&iacute;a concordante con nuestra observaci&oacute;n del crecimiento de la afectaci&oacute;n en personas cada vez de mayor edad, lo que refuerza la necesidad de actuaciones preventivas activas como la vacunaci&oacute;n para recuperar la protecci&oacute;n anti-HVA en nuestra poblaci&oacute;n