Estudio in vitro de microfiltracion de dos sistemas adhesivos en sellantes

62 p.Debido al progreso importante en el diseño de materiales y nuevas tecnicas que reducen los problemas de micro filtración en la odontología, surge la necesidad de conocer y estudiar el comportamiento marginal de los nuevos materiales para el sellado de fosas y fisuras. En el mercado han aparecido materiales que simplifican el accionar clínico, come los primer de auto grabado, con una manipulación mas rápida, y también materiales que mejoran la biomecánica del sellarte como los adhesivos de quinta generación. En nuestros tiempos, el uso del sellante convencional esta siendo modificado, debido a problemas en su aplicación, principalmente la contaminación con saliva después del grabado ácido, que provoca la micro filtración o la perdida del sellante. Para solucionar este problema aparece el uso del adhesivo acompañando al sellante. Hitt y Feigal en 1992 fueron los primeros en reportar los beneficios de aplicar un agente de unión dentinarío entre el esmalte grabado y el sellante como una forma de optimizar la fuerza de unión en un caso de humedad o contaminación salivaria. Otros estudios han confirmado los beneficios de los agentes de unión bajo los sellantes en esmalte contaminado, los cuales mejoran el éxito clínico a corto tiempo, reducen la micro filtración, refuerzan la fluidez de la resina dentro de la fisura e incrementan la fuerza de unión. El propósito de este estudio in vitro, fue comparar los valores de micro filtración en dos grupos de sellantes: un sellante mas un adhesivo de quinta generacion; y otro grupo de sellantes mas un primer de autograbado. Ambos grupos estarán sometidos a un proceso de ciclado térmico y a un proceso de cargas. El proceso del termo ciclado es para simular las condiciones intraorales adversas que pueden ser inducidas por la comida, bebida o la respiración, junto a un proceso de envejecimiento acelerado. Las cargas son para simular el intenso estrés oclusal que sufren las piezas dentarias durante la función normal y la parafuncion. Los objetivos de este estudio fueron comparar los valores de micro filtración entre los dos grupos de sellantes, determinando la micro filtración en cada grupo por separado. Para realizar este estudio se seleccionaron treinta y seis piezas dentarias extraídas por razones ortodoncicas, molares y premolares sin caries, los cuales fueron divididos al azar en dos grupos, y sellados en todas sus fisuras con el sellante y el adhesivo correspondiente. Posteriormente, las muestras se sometieron al proceso de cargas donde se aplicaron 250 ciclos de 10 Kg. 0 98 N. por 0.5 segundos en la fosa central del diente sobre el sellante. Luego, las muestras fueron sometidas a 300 ciclos térmicos, permaneciendo posteriormente 24 horas en una solución de tincion de azul de metileno al 0,2%, para finalmente cortar las muestras a través del sellante y observar y cuantificar la penetración del agente colorante en la interfase sellante-esmalte. Los resultados fueron sometidos al análisis de discrepancia estadística de Kruskall Wallis con un nivel de significancia del 95%. El test estadístico fue realizado con el software Stat Graphic Plus for Windows, Versión 1.4 ( Manugistic, Inc., Rockville, MD ). Los resultados revelan que ambos grupos de sellantes presentan un gran numero de piezas dentarias con microfiltracion grado 3. No obstante, existen diferencias significativas entre ambos, presentando un menor numero de piezas dentarias con micro filtración el grupo de sellantes que se realizo con un adhesivo de quinta generación (p=0,037878 )

Far Ultraviolet Spectra of B Stars near the Ecliptic

Spectra of B stars in the wavelength range of 911-1100 A have been obtained with the EURD spectrograph onboard the Spanish satellite MINISAT-01 with ~5 A spectral resolution. IUE spectra of the same stars have been used to normalize Kurucz models to the distance, reddening and spectral type of the corresponding star. The comparison of 8 main-sequence stars studied in detail (alpha Vir, epsilon Tau, lambda Tau, tau Tau, alpha Leo, zeta Lib, theta Oph, and sigma Sgr) shows agreement with Kurucz models, but observed fluxes are 10-40% higher than the models in most cases. The difference in flux between observations and models is higher in the wavelength range between Lyman alpha and Lyman beta. We suggest that Kurucz models underestimate the FUV flux of main-sequence B stars between these two Lyman lines. Computation of flux distributions of line-blanketed model atmospheres including non-LTE effects suggests that this flux underestimate could be due to departures from LTE, although other causes cannot be ruled out. We found the common assumption of solar metallicity for young disk stars should be made with care, since small deviations can have a significant impact on FUV model fluxes. Two peculiar stars (rho Leo and epsilon Aqr), and two emission line stars (epsilon Cap and pi Aqr) were also studied. Of these, only epsilon Aqr has a flux in agreement with the models. The rest have strong variability in the IUE range and/or uncertain reddening, which makes the comparison with models difficult.Comment: 25 pages, 6 figures, to be published in The Astrophysical Journa

Radiation background with the CMS RPCs at the LHC

The Resistive Plate Chambers (RPCs) are employed in the CMS Experiment at the LHC as dedicated trigger system both in the barrel and in the endcap. This article presents results of the radiation background measurements performed with the 2011 and 2012 proton-proton collision data collected by CMS. Emphasis is given to the measurements of the background distribution inside the RPCs. The expected background rates during the future running of the LHC are estimated both from extrapolated measurements and from simulation

Web-based monitoring tools for Resistive Plate Chambers in the CMS experiment at CERN

The Resistive Plate Chambers (RPC) are used in the CMS experiment at the trigger level and also in the standard offline muon reconstruction. In order to guarantee the quality of the data collected and to monitor online the detector performance, a set of tools has been developed in CMS which is heavily used in the RPC system. The Web-based monitoring (WBM) is a set of java servlets that allows users to check the performance of the hardware during data taking, providing distributions and history plots of all the parameters. The functionalities of the RPC WBM monitoring tools are presented along with studies of the detector performance as a function of growing luminosity and environmental conditions that are tracked over time

Water Vapor Vertical Profiles on Mars in Dust Storms Observed by TGO/NOMAD

It has been suggested that dust storms efficiently transport water vapor from the near‐surface to the middle atmosphere on Mars. Knowledge of the water vapor vertical profile during dust storms is important to understand water escape. During Martian Year 34, two dust storms occurred on Mars: a global dust storm (June to mid‐September 2018) and a regional storm (January 2019). Here we present water vapor vertical profiles in the periods of the two dust storms (Ls = 162–260° and Ls = 298–345°) from the solar occultation measurements by Nadir and Occultation for Mars Discovery (NOMAD) onboard ExoMars Trace Gas Orbiter (TGO). We show a significant increase of water vapor abundance in the middle atmosphere (40–100 km) during the global dust storm. The water enhancement rapidly occurs following the onset of the storm (Ls~190°) and has a peak at the most active period (Ls~200°). Water vapor reaches very high altitudes (up to 100 km) with a volume mixing ratio of ~50 ppm. The water vapor abundance in the middle atmosphere shows high values consistently at 60°S‐60°N at the growth phase of the dust storm (Ls = 195°–220°), and peaks at latitudes greater than 60°S at the decay phase (Ls = 220°–260°). This is explained by the seasonal change of meridional circulation: from equinoctial Hadley circulation (two cells) to the solstitial one (a single pole‐to‐pole cell). We also find a conspicuous increase of water vapor density in the middle atmosphere at the period of the regional dust storm (Ls = 322–327°), in particular at latitudes greater than 60°S

Expected Performances of the NOMAD/ExoMars instrument

NOMAD (Nadir and Occultation for MArs Discovery) is one of the four instruments on board the ExoMars Trace Gas Orbiter, scheduled for launch in March 2016. It consists of a suite of three high-resolution spectrometers – SO (Solar Occultation), LNO (Limb, Nadir and Occultation) and UVIS (Ultraviolet and Visible Spectrometer). Based upon the characteristics of the channels and the values of Signal-to-Noise Ratio obtained from radiometric models discussed in [Vandaele et al., Optics Express, 2015] and [Thomas et al., Optics Express, 2015], the expected performances of the instrument in terms of sensitivity to detection have been investigated. The analysis led to the determination of detection limits for 18 molecules, namely CO, H2O, HDO, C2H2, C2H4, C2H6, H2CO, CH4, SO2, H2S, HCl, HCN, HO2, NH3, N2O, NO2, OCS, O3. NOMAD should have the ability to measure methane concentrations <25 parts per trillion (ppt) in solar occultation mode, and 11 parts per billion in nadir mode. Occultation detections as low as 10 ppt could be made if spectra are averaged [Drummond et al., Planetary Space and Science, 2011]. Results have been obtained for all three channels in nadir and in solar occultation

Zero by 2030 and OneHealth: The multidisciplinary challenges of rabies control and elimination

"Rabies, caused by a negative strand RNA-virus belonging to the genus Lyssavirus (family Rhabdoviridae of the order Mononegavirales), remains of global concern [1]. This vaccine-preventable viral zoonotic disease is present in more than 150 countries and territories [2]. Ac- cording to the World Health Organization (WHO), rabies is estimated to cause ~59,000 human deaths annually, with 95% of cases occurring in Africa and Asia [3,4]. However, rabies still occurs in other regions, such as Latin America and the Caribbean [5–8], Central Asia and the Middle East [9,10]. Whilst a number of animals can host the rabies virus, dogs are the main source of human rabies deaths, contributing up to 99% of all rabies transmissions to humans. Dog-mediated rabies has been eliminated from Western Europe, Canada, the United States of America (USA), Japan and some Latin American countries [11]. Nevertheless, the risk of reintroduction and disease among travellers to risk areas is a matter of concern [12–15]. As occurred with many other communicable and non-communicable diseases, the 2020–2022 COVID-19 pandemic negatively impacted the efforts of control and reemergence of rabies in certain countries [7,16,17]. Post-pandemic challenges to enhance con- trol and prevention are multiple and need urgent actions to achieve the goal in eight years by 2030 [16].

CMS RPC muon detector performance with 2010-2012 LHC data

The muon spectrometer of the CMS (Compact Muon Solenoid) experiment at the Large Hadron Collider (LHC) is equipped with a redundant system made of Resistive Plate Chambers (RPCs) and Drift Tube (DT) chambers in the barrel, RPC and Cathode Strip Chambers (CSCs) in the endcap region. In this paper, the operations and the performance of the RPC system during the first three years of LHC activity are presented. The stability of the RPC performance, in terms of efficiency, cluster size and noise, is also reported. Finally, the radiation background levels on the RPC system have been measured as a function of the LHC luminosity. Extrapolations to the High Luminosity LHC conditions are also discussed

Performance of the gas gain monitoring system of the CMS RPC muon detector

The RPC muon detector of the CMS experiment at the LHC (CERN, Geneva, Switzerland) is equipped with a Gas Gain Monitoring (GGM) system. A report on the stability of the system during the 2011-2012 data taking run is given, as well as the observation of an effect which suggests a novel method for the monitoring of gas mixture composition.Comment: Presented at RPC2014, Beijing, China. Accepted for publication on JINS

Rate and duration of hospitalisation for acute pulmonary embolism in the real-world clinical practice of different countries : Analysis from the RIETE registry

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