1,493 research outputs found

    Scanning tunneling microscopy of electrochemically activated platinum surfaces : A direct ex-situ determination of the electrode nanotopography

    Get PDF
    A direct scanning tunneling microscopy ex-situ determination on the nanometer scale of the topography of electrochemically highly activated platinum electrodes is presented. A correlation between catalytic activity and surface microtopography becomes evident. This result gives support to a structural model for the activated electrode surface. In the model, a volume with a pebble-like structure allows electrocatalytic processes to occur practically free of diffusion relaxation contributions under usual voltammetric conditions.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicada

    Static quantities of the W boson in the SU_L(3) X U_X(1) model with right-handed neutrinos

    Full text link
    The static electromagnetic properties of the WW boson, Δκ\Delta \kappa and ΔQ\Delta Q, are calculated in the SU_L(3)} \times U_X(1) model with right-handed neutrinos. The new contributions from this model arise from the gauge and scalar sectors. In the gauge sector there is a new contribution from a complex neutral gauge boson Y0Y^0 and a singly-charged gauge boson Y±Y^\pm. The mass of these gauge bosons, called bileptons, is expected to be in the range of a few hundreds of GeV according to the current bounds from experimental data. If the bilepton masses are of the order of 200 GeV, the size of their contribution is similar to that obtained in other weakly coupled theories. However the contributions to both ΔQ\Delta Q and Δκ\Delta \kappa are negligible for very heavy or degenerate bileptons. As for the scalar sector, an scenario is examined in which the contribution to the WW form factors is identical to that of a two-Higgs-doublet model. It is found that this sector would not give large corrections to Δκ\Delta \kappa and ΔQ\Delta Q.Comment: New material included. Final version to apppear in Physical Review

    Treatment with implants in patients with diabetes. A 7-year comparative study

    Get PDF
    Introducción. La implantología oral puede constituir una modalidad terapéutica en el tratamiento prostodóncico de los pacientes con compromiso médico. El estudio muestra la evaluación del tratamiento con implantes en pacientes con diabetes comparados con pacientes sin diabetes. Métodos. 48 pacientes edéntulos totales (24 pacientes diabéticos y 24 no diabéticos) fueron tratados con 96 implan- tes con superficie arenada y grabada Galimplant ® en la mandíbula para su rehabilitación prostodóncica con sobre- dentaduras mandibulares. 2 implantes fueron insertados en cada paciente. Los implantes fueron cargados funcional- mente tras un periodo de tiempo de 6 semanas con retenedores de fricción. Los hallazgos clínicos (implantológicos y prostodóncicos) se han seguido durante 7 años. Resultados. Los resultados indican una supervivencia de los implantes del 95,8%. Durante el periodo de seguimeinto clínico se perdieron 4 implantes (dos implantes en cada grupo). La pérdida de hueso marginal media fué de 0,7 mm en ambos grupos. El 100% de los pacientes fueron tratados mediante una sobredentadura implantorretenida con anclajes de fricción. En 14 pacientes se realizaron cambios en los componentes plásticos de los ataches. El seguimiento clínico medio fue de 82,5 meses (60-102 meses). Conclusiones. Los resultados del presente estudio indican que el tratamiento con implantes dentales en pacientes diabéticos es una terapéutica exitosa sin diferencias entre los pacientes diabéticos y no diabéticos. PALABRAS CLAVE: Implantes dentales, pacientes geriátricos, diabetes mellitus, sobredentaduras, oseo- integración, implantología oral.Introduction. Implant dentistry can to constitute a therapeutic modality in the prosthodontic treatment of medically compromised patients. This study reports the evaluation of treatment with implants in patients with diabetes compared with patients without diabetes. Methods. 48 edentulous patients (24 diabetic patients and 24 non-diabetic patients) were treated with 96 Galimplant ® sand-blasted and acid-etched surface implants for prosthodontic rehabilitation with mandibular overdentures. Two implants were inserted in each patient. Implants were loaded after a healing free-loading period between 6 weeks with locator attaches. Clinical findings (implant and prosthodontics) were followed during at 7 years. Results. Clinical results indicate a survival rate of implants of 95.8% in both groups. Four implant was lost during the follow-up period (two implants in each group). Media marginal bone loss was 0.7 mm in both groups. 100% of patients were treated with overdentures retained with 2 implants with locator attaches. Changes in plastic components of attaches were reported in 14 patients. The media follow-up was of 82.5 months (60-102 months). Conclusions. Clinical results of this study indicate that treatment with dental implants in diabetic patients is a successful implant treatment without differences with nondiabetic patients

    Efecto de las fuentes de polen sobre el rendimiento en la extracción de aceite y perfil de ácidos grasos de las semillas de dátil (Phoenix dactylifera L.) cultivar Medjool de México

    Get PDF
    The present investigation aimed to assess the effect of pollen sources on the mass, dimension, oil content and fatty acid profile of the seeds from female palms of the Medjool date cultivar. The palms were pollinated with Deglet Noor, Khadrawy, Medjool and Zahidi cultivars. In addition, three palms were pollinated as the treatment control. The fatty acids were evaluated by gas chromatography-mass spectrometry. The surface morphology of date seed powder was examined using SEM, before and after n-hexane interaction. The seeds of the Medjool treatment had the greatest mass (1.42 g), but the lowest oil content (5.37% w/w); the control seeds showed smaller mass (1.21 g), but higher oil content (13.57% w/w). The proportion of fatty acids varied significantly among the treatments with respect to the control. The most abundant fatty acids were oleic (C18:1), lauric (C12:0), myristic (C14:0), palmitic (C16:0), linoleic (C18:2), and stearic (C18:0). Together these fatty acids presented a composition between 98.3 and 98.67% for treatments, and 99.0% for the control. The results indicate that the pollen sources from Deglet Noor, Khadrawy, Medjool and Zahidi cultivars had a significant effect on mass, dimension, oil content and fatty acid profile of the seeds of the date cultivar Medjool. The date seed oil could be used as edible oil, in food products, and in pharmaceutical and cosmetic applications.La presente investigación tuvo como objetivo evaluar el efecto de las fuentes de polen, sobre la masa, dimensión, contenido de aceite y el perfil de ácidos grasos de las semillas de dátil del cultivar Medjool. Las palmas hembras del cultivar Medjool fueron polinizadas con cultivares Deglet Noor, Khadrawy, Medjool y Zahidi. Además, tres palmas fueron polinizadas como tratamiento control. Los ácidos grasos se evaluaron por cromatografía de gases-espectrometría de masas. La morfología de la superficie del polvo de semillas de dátil se examinó utilizando un equipo SEM, antes y después de la interacción n-hexano. Las semillas del tratamiento Medjool resultaron con mayor masa (1,42 g), pero menor contenido de aceite (5,37% p/p); la semilla control, mostró una masa más pequeña (1,21 g), pero un mayor contenido de aceite (13,57% p/p). La composición de ácidos grasos varió significativamente entre los tratamientos con respecto al control. Los ácidos grasos mayoritarios fueron: oleico (C18:1), láurico (C12:0), mirístico (C14:0), palmítico (C16:0), linoleico (C18:2) and esteárico (C18:0). En total, estos ácidos grasos alcanzan una composición entre 98.3 y 98.67% para los tratamientos, y 99.0% para el control. Los resultados indican que la fuente de polen de los cultivares Deglet Noor, Khadrawy, Medjool y Zahidi tiene un efecto significativo sobre la masa, dimensión, contenido de aceite y el perfil de ácidos grasos de la semilla del cultivar de dátil Medjool. El aceite de la semilla de dátil, podría usarse como aceite comestible, productos alimenticios, aplicaciones farmacéuticas y cosméticas

    Efectos del tamaño de camada y de la suplementación de la dieta de conejas lactantes con ácidos grasos poliinsaturados n-3

    Get PDF
    Se han empleado 2 piensos isofibrosos, isoenergéticos e isoproteicos formulados con 2 fuentes de grasa. En el pienso AGPI (ácidos grasoso poliinsatudados n-3) se incluyó un 6% de un suplemento con un 50% de extracto etéreo concentrado en AGPI n-3, a partir de aceite refinado de salmón, y en el pienso C, un 3% de grasa mezcla

    Postcranial morphology of the middle Pleistocene humans from Sima de los Huesos, Spain

    Get PDF
    Current knowledge of the evolution of the postcranial skeleton in the genus Homo is hampered by a geographically and chronologically scattered fossil record. Here we present a complete characterization of the postcranium of the middle Pleistocene paleodeme from the Sima de los Huesos (SH) and its paleobiological implications. The SH hominins show the following: (i) wide bodies, a plesiomorphic char- acter in the genus Homo inherited from their early hominin ancestors; (ii) statures that can be found in modern human middle-latitude pop- ulations that first appeared 1.6–1.5 Mya; and (iii) large femoral heads in some individuals, a trait that first appeared during the middle Pleistocene in Africa and Europe. The intrapopulational size variation in SH shows that the level of dimorphism was similar to modern humans (MH), but the SH hominins were less encephalized than Ne- andertals. SH shares many postcranial anatomical features with Ne- andertals. Although most of these features appear to be either plesiomorphic retentions or are of uncertain phylogenetic polarity, a few represent Neandertal apomorphies. Nevertheless, the full suite of Neandertal-derived features is not yet present in the SH popula- tion. The postcranial evidence is consistent with the hypothesis based on the cranial morphology that the SH hominins are a sister group to the later Neandertals. Comparison of the SH postcranial skeleton to other hominins suggests that the evolution of the postcranium oc- curred in a mosaic mode, both at a general and at a detailed level

    The LAEX and NASA portals for CoRoT public data

    Get PDF
    * Aims. We describe here the main functionalities of the LAEX (Laboratorio de Astrofisica Estelar y Exoplanetas/Laboratory for Stellar Astrophysics and Exoplanets) and NASA portals for CoRoT Public Data. The CoRoT archive at LAEX was opened to the community in January 2009 and is managed in the framework of the Spanish Virtual Observatory. NStED (NASA Star and Exoplanet Database) serves as the CoRoT portal for the US astronomical community. NStED is a general purpose stellar and exoplanet archive with the aim of providing support for NASA planet finding and characterisation goals, and the planning and support of NASA and other space missions. CoRoT data at LAEX and NStED can be accessed at http://sdc.laeff.inta.es/corotfa/ and http://nsted.ipac.caltech.edu,respectively. * Methods. Based on considerable experience with astronomical archives, the aforementioned archives are designed with the aim of delivering science-quality data in a simple and efficient way. * Results. LAEX and NStED not only provide access to CoRoT Public Data but furthermore serve a variety of observed and calculated astrophysical data. In particular, NStED provides scientifically validated information on stellar and planetary data related to the search for and characterization of extrasolar planets, and LAEX makes any information from Virtual Observatory services available to the astronomical community.Comment: Accepted for publication in Astronomy & Astrophysic

    TRIB3 suppresses tumorigenesis by controlling mTORC2/AKT/FOXO signaling.

    Get PDF
    In a recent article, we found that Tribbles pseudokinase 3 (TRIB3) plays a tumor suppressor role and that this effect relies on the dysregulation of the phosphorylation of v-akt murine thymoma viral oncogene homolog (AKT) by the mammalian target of rapamycin complex 2 (mTORC2 complex), and the subsequent hyperphosphorylation and inactivation of the transcription factor Forkhead box O3 (FOXO3)

    Colección documental de Cuéllar (934-1492)

    Get PDF
    Colabora: Consejería de Cultura y Turismo de la Junta de Castilla y Leó
    corecore