144 research outputs found

    Estimation of the mechanical properties of the eye through the study of its vibrational modes

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    Measuring the eye's mechanical properties in vivo and with minimally invasive techniques can be the key for individualized solutions to a number of eye pathologies. The development of such techniques largely relies on a computational modelling of the eyeball and, it optimally requires the synergic interplay between experimentation and numerical simulation. In Astrophysics and Geophysics the remote measurement of structural properties of the systems of their realm is performed on the basis of (helio-)seismic techniques. As a biomechanical system, the eyeball possesses normal vibrational modes encompassing rich information about its structure and mechanical properties. However, the integral analysis of the eyeball vibrational modes has not been performed yet. Here we develop a new finite difference method to compute both the spheroidal and, specially, the toroidal eigenfrequencies of the human eye. Using this numerical model, we show that the vibrational eigenfrequencies of the human eye fall in the interval 100 Hz - 10 MHz. We find that compressible vibrational modes may release a trace on high frequency changes of the intraocular pressure, while incompressible normal modes could be registered analyzing the scattering pattern that the motions of the vitreous humour leave on the retina. Existing contact lenses with embebed devices operating at high sampling frequency could be used to register the microfluctuations of the eyeball shape we obtain. We advance that an inverse problem to obtain the mechanical properties of a given eye (e.g., Young's modulus, Poisson ratio) measuring its normal frequencies is doable. These measurements can be done using non-invasive techniques, opening very interesting perspectives to estimate the mechanical properties of eyes in vivo. Future research might relate various ocular pathologies with anomalies in measured vibrational frequencies of the eye.Comment: Published in PLoS ONE as Open Access Research Article. 17 pages, 5 color figure

    Análisis de los factores de riesgo de las fracturas vertebrales osteoporóticas.

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    Hemos realizado un estudio prospectivo de cohortes con pacientes ingresados en el servicio de Cirugía Ortopédica y Traumatología del Hospital Clínico Universitario de Valencia que habían sufrido una fractura de perfil osteoporótico desde octubre 2004 hasta abril 2005, incluyéndose un total de 59 pacientes con fractura osteoporótica vertebral y 390 pacientes con fractura osteoporótica no vertebral. Este estudio se ha desarrollado dentro del proyecto GIOS (Proyecto de Gestión Integral del manejo clínico de pacientes mayores de 50 años con fractura osteoporótica). Se han analizado los factores de riesgo de los pacientes que presentan una fractura osteoporótica vertebral y su distribución por edades, y se ha comparado con los de las fracturas osteoporóticas no vertebrales (cadera, radio distal y húmero proximal). Se han hallado diferencias en la incidencia con respecto a la edad y una mayor influencia de factores no relacionados con la edad en las fracturas vertebrales osteoporóticas que en las no vertebrales. En los resultados obtenidos se aprecia que menos del 10% de los pacientes incluidos en el estudio estaban previamente tratados contra la osteoporosis, por lo que es deseable detectar los pacientes con factores de riesgo de fractura osteoporótica para iniciar tratamiento preventivo. La implantación de proyectos para el manejo de pacientes osteoporóticos como el utilizado en el presente estudio (GIOS), es deseable para la expansión de la prevención primaria y secundaria de la osteoporosis.This prospective cohorts study includes patients who were hospitalized, due to osteoporotic fractures, from October 2004 to April 2005, at the Orthopaedics and Trauma Department at Hospital Clínico Universitario of Valencia. This study is included in GIOS Project (Integral Management Project for patients older than 50 years suffering osteoporotic fracture). A total of 449 patients have been included in the study, 59 patients suffered osteoporotic vertebral fracture and 390 patients suffering non-vertebral osteoporotic fractures, such as hip, distal radius and proximal humerus. The risk fac- tors of both groups have been analyzed and matched by age to be compared. It has been found incidence differences in age between both groups, as well as a greater influence of non-related age factors in the osteoporotic vertebral fracture group. From the results, it can be appreciated that not even a 10% of the patients included in the study, were previously tre- ated against osteoporosis, being desirable to detect patients with a high risk of suffering this type of fracture, in order to reduce the risk factors and start preventive treatment. Due to the growth of elder population, the number of osteoporotic fractures will increase substantially in future years, unless cost-effective control programs as GIOS are implanted

    Amplitude, Latency, and Peak Velocity in Accommodation and Disaccommodation Dynamics.

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    The aim of this work was to ascertain whether there are differences in amplitude, latency, and peak velocity of accommodation and disaccommodation responses when different analysis strategies are used to compute them, such as fitting different functions to the responses or for smoothing them prior to computing the parameters. Accommodation and disaccommodation responses from four subjects to pulse changes in demand were recorded by means of aberrometry. Three different strategies were followed to analyze such responses: fitting an exponential function to the experimental data; fitting a Boltzmann sigmoid function to the data; and smoothing the data. Amplitude, latency, and peak velocity of the responses were extracted. Significant differences were found between the peak velocity in accommodation computed by fitting an exponential function and smoothing the experimental data (mean difference 2.36 D/s). Regarding disaccommodation, significant differences were found between latency and peak velocity, calculated with the two same strategies (mean difference of 0.15 s and -3.56 D/s, resp.). The strategy used to analyze accommodation and disaccommodation responses seems to affect the parameters that describe accommodation and disaccommodation dynamics. These results highlight the importance of choosing the most adequate analysis strategy in each individual to obtain the parameters that characterize accommodation and disaccommodation dynamics

    Atopic dermatitis incidence and risk factors in young adults in Castellon (Spain): A prospective cohort study

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    Introduction: There are few atopic dermatitis (AD) incidence cohort studies in young adults, the etiology of this disease remains obscure, and AD risk factors in adults are not well understood. The objective of this study was to estimate AD ten-year incidence and prevalence in a cohort of adolescent aged 14–16 at inception in Castellon province in Valencia Region, Spain and describe related risk factors. Material and methods: From 2002 to 2012, a population-based prospective cohort study was carried out. Questionnaires from the International Study of Asthma and Allergies in Childhood (ISAAC) were used with an additional questionnaire for related factors completed by participants and their parents, respectively, in 2002. In 2012 the same questionnaires were completed by the participants’ through a telephone interview, and incidence and prevalence of AD were estimated. Directed acyclic graphs, Poisson regression and inverse probability weighted regression adjustment were used. Results: The participation rate was 79.5% (1435/1805) with AD lifetime prevalence of 34.9% and AD incidence of 13.5 per 1000 person years. Females presented higher prevalence and incidence than males. After adjustment significant risk factors were being female, history of asthma or allergic rhinitis, family history of AD, history of respiratory infections, history of bronchitis, history of pneumonia, history of sinusitis, and birthplace outside Castellon province. The highest AD population attributable risks were female, 30.3%, and history of respiratory infections 15.3%. Differences with AD childhood risk factors were found. Conclusions: AD incidence in our cohort was high and several risks factors were related to AD

    Impacto de las recomendaciones sobre la vacunación de hepatitis A en niños de familias inmigrantes de países de alta endemia residentes en Castellón

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    Introducción: Los hijos de inmigrantes procedentes de países de alta endemia de hepatitis A que viajan para visitar a sus familiares, forman un grupo al que se recomienda la vacunación previa al viaje. En el Departamento de La Plana (Castellón), a finales de noviembre de 2012, hubo un aumento de casos de hepatitis A en niños que regresaban del viaje de su país de origen (Marruecos). Se realizaron actuaciones para promocionar la vacunación de estos niños antes de los viajes a su país en la primavera/verano de 2013. Objetivo: Evaluar el impacto de estas recomendaciones. Métodos: Estudio retrospectivo observacional comparativo usando datos del Registro de Vacunas. Se compararon los periodos previo y posterior a la intervención. Resultados: Hubo un aumento en el número de niños vacunados (de 33 a 263). El mayor incremento se observó en niños origen magrebí del Departamento de La Plana (pasó de 2 a 139). En este Departamento se estimó una cobertura del 17%. Conclusiones: Las medidas adoptadas tuvieron un impacto moderado. La cobertura sigue siendo baja. Conviene insistir en la vacunación preexposición de estos niños. Deben implicarse los servicios de salud pública, atención primaria, vacunación internacional y escolares

    Aberrant upregulation of the glycolytic enzyme PFKFB3 in CLN7 neuronal ceroid lipofuscinosis

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    CLN7 neuronal ceroid lipofuscinosis is an inherited lysosomal storage neurodegenerative disease highly prevalent in children. CLN7/MFSD8 gene encodes a lysosomal membrane glycoprotein, but the biochemical processes affected by CLN7-loss of function are unexplored thus preventing development of potential treatments. Here, we found, in the Cln7∆ex2 mouse model of CLN7 disease, that failure in autophagy causes accumulation of structurally and bioenergetically impaired neuronal mitochondria. In vivo genetic approach reveals elevated mitochondrial reactive oxygen species (mROS) in Cln7∆ex2 neurons that mediates glycolytic enzyme PFKFB3 activation and contributes to CLN7 pathogenesis. Mechanistically, mROS sustains a signaling cascade leading to protein stabilization of PFKFB3, normally unstable in healthy neurons. Administration of the highly selective PFKFB3 inhibitor AZ67 in Cln7∆ex2 mouse brain in vivo and in CLN7 patients-derived cells rectifies key disease hallmarks. Thus, aberrant upregulation of the glycolytic enzyme PFKFB3 in neurons may contribute to CLN7 pathogenesis and targeting PFKFB3 could alleviate this and other lysosomal storage diseases

    Aberrant upregulation of the glycolytic enzyme PFKFB3 in CLN7 neuronal ceroid lipofuscinosis

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    CLN7 neuronal ceroid lipofuscinosis is an inherited lysosomal storage neurodegenerative disease highly prevalent in children. CLN7/MFSD8 gene encodes a lysosomal membrane glycoprotein, but the biochemical processes affected by CLN7-loss of function are unexplored thus preventing development of potential treatments. Here, we found, in the Cln7∆ex2 mouse model of CLN7 disease, that failure in autophagy causes accumulation of structurally and bioenergetically impaired neuronal mitochondria. In vivo genetic approach reveals elevated mitochondrial reactive oxygen species (mROS) in Cln7∆ex2 neurons that mediates glycolytic enzyme PFKFB3 activation and contributes to CLN7 pathogenesis. Mechanistically, mROS sustains a signaling cascade leading to protein stabilization of PFKFB3, normally unstable in healthy neurons. Administration of the highly selective PFKFB3 inhibitor AZ67 in Cln7∆ex2 mouse brain in vivo and in CLN7 patients-derived cells rectifies key disease hallmarks. Thus, aberrant upregulation of the glycolytic enzyme PFKFB3 in neurons may contribute to CLN7 pathogenesis and targeting PFKFB3 could alleviate this and other lysosomal storage diseases.This work was funded by the European Regional Development Fund, European Union’s Horizon 2020 Research and Innovation Programme (BATCure grant No. 666918 to J.P.B., S.E.M., D.L.M., S.S., and T.R.M.; PANA grant No. 686009 to A.A.), Agencia Estatal de Investigación (PID2019-105699RB-I00/AEI/10.13039/501100011033 and RED2018‐102576‐T to J.P.B.; SAF2017-90794-REDT to A.A.), Instituto de Salud Carlos III (CB16/10/00282 to J.P.B.; PI18/00285; RD16/0019/0018 to A.A.), Junta de Castilla y León (CS/151P20 and Escalera de Excelencia CLU-2017-03 to J.P.B. and A.A.), Ayudas Equipos Investigación Biomedicina 2017 Fundación BBVA (to J.P.B.), and Fundación Ramón Areces (to J.P.B. and A.A.). SM benefits from MRC funding to the MRC Laboratory for Molecular Cell Biology University Unit at UCL (award code MC_U12266B) towards lab and office space. Part of this work was funded by Gero Discovery L.L.C. M.G.M. is an ISCIII-Sara Borrel contract recipient (CD18/00203)

    INTERLOCKING RESONANCE PATTERNS IN GALAXY DISKS

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    We have developed a method for finding dynamical resonances in disk galaxies using the change in sense of the radial component of the in-plane velocity at a resonance radius. Using simulations we show that we would expect to find these changes at corotation radii with a weaker effect at the Lindblad resonances. The method works well with observations at high spectral and angular resolutions, and is suited to the analysis of two-dimensional velocity fields in Hα from Fabry-Perot spectroscopy. We find clear indications of resonance effects in the disk velocity fields of virtually all of the 104 galaxies. The number of resonance radii detected ranges from one to seven, with a median of four. The frequency curves Ω, Ω ± κ/2, Ω ± κ/4 against radius for all the galaxies led us to discover a pattern in over 70% of the sample: given two pattern speeds, say Ω1 and Ω2, the OLR of Ω1 coincides with the corotation of Ω2, and the inner 4:1 resonance of Ω2 coincides with the corotation of Ω1. Although the second coincidence has been predicted, a prediction of this double coincidence is not found in the literature. This pattern is found once in 42 of the galaxies, twice in a further 26, three times in 5, and even four times in 1 galaxy. We also compute the ratio of corotation radius to bar length where we have sufficient image quality, finding a mean value of 1.3, and a shallow increase toward later type galaxies

    State recognition for ‘contested languages’: a comparative study of Sardinian and Asturian, 1992–2010

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    While the idea of a named language as a separate and discrete identity is a political and social construct, in the cases of Sardinian and Asturian doubts over their respective ‘languageness’ have real material consequences, particularly in relation to language policy decisions at the state level. The Asturian example highlights how its lack of official status means that it is either ignored or subjected to repeated challenges to its status as a language variety deserving of recognition and support, reflecting how ‘official language’ in the Spanish context is often understood in practice as synonymous with the theoretically broader category of ‘language’. In contrast, the recent state recognition of Sardinian speakers as a linguistic minority in Italy (Law 482/1999) illustrates how legal recognition served to overcome existing obstacles to the implementation of regional language policy measures. At the same time, the limited subsequent effects of this Law, particularly in the sphere of education, are a reminder of the shortcomings of top-down policies which fail to engage with the local language practices and attitudes of the communities of speakers recognized. The contrastive focus of this article thus acknowledges the continued material consequences of top-down language classification, while highlighting its inadequacies as a language policy mechanism which reinforces artificial distinctions between speech varieties and speakers deserving of recognition
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