5,313 research outputs found

    Host-Guest-Mediated Epitope Presentation on Self-Assembled Peptide Amphiphile Hydrogels

    Get PDF
    A key feature in biomaterial design is the incorporation of bioactive signals into artificial constructs to stimulate tissue regeneration. Most currently used hydrogel cell culture systems depend on the covalent attachment of extracellular matrix (ECM)-derived peptides to either macromolecular units or smaller self-assembling building blocks, thereby restricting biosignal presentation and adaptability. However, new ways to rationally incorporate adhesion epitopes through noncovalent interactions would offer opportunities to better recreate the dynamic and reversible nature of the native ECM. Here, we report on a noncovalent epitope presentation approach mediated by host–guest interactions. Using peptide amphiphile hydrogels, we demonstrate that the adamantane/β-cyclodextrin pair can be used to anchor RGDS cell adhesion signals onto self-assembled hydrogels via host–guest interactions. We evaluate hydrogel morphological and rheological properties as well as fibroblast attachment, organization, and spreading when cultured atop these scaffolds. This host–guest-mediated epitope display might lead to new self-assembling hydrogels for improved cell culture applications in fields such as tissue engineering and regenerative medicine

    Estudio de la iluminación natural en la edificación

    Get PDF
    En la estación de radiación solar e iluminación de alta calidad del International Daylight Measurement Program (IDMP) en Madrid ubicada en la terraza norte de la E.T.S. de Arquitectura de la Universidad Politécnica de Madrid (40º 25’ N, 3º 41’ W) se está realizando un estudio conjunto entre profesores de la ETSAM y de la EUATM sobre la iluminación natural en la Edificación. Desde hace más de un año, se están midiendo iluminancias globales en superficies horizontales, en superficies verticales con las cuatro orientaciones (N, S, E y O) y en superficies inclinadas con distintos ángulos de inclinación mediante un domo semiesférico sobre el que se colocan los sensores fotométricos. Todas estas medidas para los tres tipos de cielo (despejado, parcialmente cubierto y cubierto). También se ha construido un modelo a escala de un local de la ETSAM con la finalidad de medir la iluminación natural simultáneamente en el local y en el modelo reducido. Una vez conocida la viabilidad del modelo se ha estudiado la iluminación natural que tendría dicho local, orientado al norte en la realidad, si estuviese orientado hacia el Sur, el Este o el Oeste. Con todo esto se han realizado varios trabajos de fin de máster del Máster en Técnicas y Sistemas de Edificación de la EUATM y se continúan realizando otros

    Towards a new generation axion helioscope

    Get PDF
    We study the feasibility of a new generation axion helioscope, the most ambitious and promising detector of solar axions to date. We show that large improvements in magnetic field volume, x-ray focusing optics and detector backgrounds are possible beyond those achieved in the CERN Axion Solar Telescope (CAST). For hadronic models, a sensitivity to the axion-photon coupling of \gagamma\gtrsim {\rm few} \times 10^{-12} GeV1^{-1} is conceivable, 1--1.5 orders of magnitude beyond the CAST sensitivity. If axions also couple to electrons, the Sun produces a larger flux for the same value of the Peccei-Quinn scale, allowing one to probe a broader class of models. Except for the axion dark matter searches, this experiment will be the most sensitive axion search ever, reaching or surpassing the stringent bounds from SN1987A and possibly testing the axion interpretation of anomalous white-dwarf cooling that predicts mam_a of a few meV. Beyond axions, this new instrument will probe entirely unexplored ranges of parameters for a large variety of axion-like particles (ALPs) and other novel excitations at the low-energy frontier of elementary particle physics.Comment: 37 pages, 11 figures, accepted for publication in JCA

    The International Axion Observatory (IAXO)

    Get PDF
    The International Axion Observatory (IAXO) is a new generation axion helioscope aiming at a sensitivity to the axion-photon coupling of a few 1012^{12} GeV1^{-1}, i.e. 1 - 1.5 orders of magnitude beyond the one currently achieved by CAST. The project relies on improvements in magnetic field volume together with extensive use of x-ray focusing optics and low background detectors, innovations already successfully tested in CAST. Additional physics cases of IAXO could include the detection of electron-coupled axions invoked to solve the white dwarfs anomaly, relic axions, and a large variety of more generic axion-like particles (ALPs) and other novel excitations at the low-energy frontier of elementary particle physics. This contribution is a summary of our paper [1] to which we refer for further details.Comment: 4 pages, 2 figures. To appear in the proceedings of the 7th Patras Workshop on Axions, WIMPs and WISPs, Mykonos, Greece, 201

    Three-body structure of low-lying 18Ne states

    Full text link
    We investigate to what extent 18Ne can be descibed as a three-body system made of an inert 16O-core and two protons. We compare to experimental data and occasionally to shell model results. We obtain three-body wave functions with the hyperspherical adiabatic expansion method. We study the spectrum of 18Ne, the structure of the different states and the predominant transition strengths. Two 0+, two 2+, and one 4+ bound states are found where they are all known experimentally. Also one 3+ close to threshold is found and several negative parity states, 1-, 3-, 0-, 2-, most of them bound with respect to the 16O excited 3- state. The structures are extracted as partial wave components, as spatial sizes of matter and charge, and as probability distributions. Electromagnetic decay rates are calculated for these states. The dominating decay mode for the bound states is E2 and occasionally also M1.Comment: 17 pages, 5 figures (version to appear in EPJA

    Design and evaluation of a treatment programme for Spanish adolescents with overweight and obesity. The EVASYON Study

    Get PDF
    Background The prevalence of overweight and obesity (OW/OB) among adolescents worldwide has increased since the 60 s. Spain has reached one of the highest OW/OB prevalence rates among adolescents from European countries. The aim of this methodological paper is to describe the design and evaluation in the EVASYON study (Development, implementation and evaluation of the efficacy of a therapeutic programme for adolescents with OW/OB: integral education on nutrition and physical activity). Methods/Design The EVASYON was planned by a multidisciplinary team to treat OW/OB in Spanish adolescents. The EVASYON is a multi-centre study conducted in 5 hospitals in 5 Spanish cities (Granada, Madrid, Pamplona, Santander and Zaragoza) and two hundred and four OW/OB Spanish adolescents were recruited for this intervention. The treatment was implemented for approximately one-year follow-up. The adolescents were treated in groups of a maximum of 10 subjects; each group had 20 visits during the treatment period in two phases: intensive during the first 2 months (1st to 9th visits), and extensive during the last 11 months (10th to 20th visits). In order to assess the efficacy of the treatment, 8 dimensions were measured: diet; physical activity and fitness; eating behaviour; body composition; haematological profile; metabolic profile; minerals and vitamins; immuno-inflammatory markers. Moreover, genetic polymorphisms were also determined. Discussion The treatment programme developed in the EVASYON study was designed as a national pilot study to be implemented as an effective treatment for adolescents with OW/OB into the Spanish Health Care Service

    CAST constraints on the axion-electron coupling

    Full text link
    In non-hadronic axion models, which have a tree-level axion-electron interaction, the Sun produces a strong axion flux by bremsstrahlung, Compton scattering, and axio-recombination, the "BCA processes." Based on a new calculation of this flux, including for the first time axio-recombination, we derive limits on the axion-electron Yukawa coupling g_ae and axion-photon interaction strength g_ag using the CAST phase-I data (vacuum phase). For m_a < 10 meV/c2 we find g_ag x g_ae< 8.1 x 10^-23 GeV^-1 at 95% CL. We stress that a next-generation axion helioscope such as the proposed IAXO could push this sensitivity into a range beyond stellar energy-loss limits and test the hypothesis that white-dwarf cooling is dominated by axion emission

    Factors associated with lesion detection in colonoscopy among different indications

    Get PDF
    Background and objective: Different factors may influence colonoscopy performance measures. We aimed to analyze procedure- and endoscopist-related factors associated with detection of colorectal lesions and whether these factors have a similar influence in the context of different colonoscopy indications: positive fecal immunochemical test (+FIT) and post-polypectomy surveillance colonoscopies. Methods: This multicenter cross-sectional study included adults aged 40-80 years. Endoscopists (N = 96) who had performed ≥50 examinations were assessed for physician-related factors. Adenoma detection rate (ADR), adenomas per colonoscopy rate (APCR), advanced ADR, serrated polyp detection (SDR), and serrated polyps per colonoscopy rate (SPPCR) were calculated. Results: We included 12,932 procedures, with 4810 carried out after a positive FIT and 1967 for surveillance. Of the 96 endoscopists evaluated, 43.8% were women, and the mean age was 41.9 years. The ADR, advanced ADR, and SDR were 39.7%, 17.7%, and 12.8%, respectively. Adenoma detection rate was higher in colonoscopies after a +FIT (50.3%) with a more than doubled advanced ADR compared to non-FIT procedures (27.6% vs. 13.0%) and similar results in serrated lesions (14.7% vs. 13.5%). Among all the detection indicators analyzed, withdrawal time was the only factor independently related to improvement (p < 0.001). Regarding FIT-positive and surveillance procedures, for both indications, withdrawal time was also the only factor associated with a higher detection of adenomas and serrated polyps (p < 0.001). Endoscopist-related factors (i.e., weekly hours dedicated to endoscopy, annual colonoscopy volume and lifetime number of colonoscopies performed) had also impact on lesion detection (APCR, advanced ADR and SPPCR). Conclusions: Withdrawal time was the factor most commonly associated with improved detection of colonic lesions globally and in endoscopies for + FIT and post-polypectomy surveillance. Physician-related factors may help to address strategies to support training and service provision. Our results can be used for establishing future benchmarking and quality improvement in different colonoscopy indications

    Search for the Higgs boson in events with missing transverse energy and b quark jets produced in proton-antiproton collisions at s**(1/2)=1.96 TeV

    Get PDF
    We search for the standard model Higgs boson produced in association with an electroweak vector boson in events with no identified charged leptons, large imbalance in transverse momentum, and two jets where at least one contains a secondary vertex consistent with the decay of b hadrons. We use ~1 fb-1 integrated luminosity of proton-antiproton collisions at s**(1/2)=1.96 TeV recorded by the CDF II experiment at the Tevatron. We find 268 (16) single (double) b-tagged candidate events, where 248 +/- 43 (14.4 +/- 2.7) are expected from standard model background processes. We place 95% confidence level upper limits on the Higgs boson production cross section for several Higgs boson masses ranging from 110 GeV/c2 to 140 GeV/c2. For a mass of 115 GeV/c2 the observed (expected) limit is 20.4 (14.2) times the standard model prediction.Comment: 8 pages, 2 figures, submitted to Phys. Rev. Let
    corecore