2,284 research outputs found

    Terapia fototérmica mediante un fotosensibilizador intracelular: La Croconaina

    Get PDF
    El mundo de la nanomedicina aplicada en el tratamiento de cáncer está creciendo muy rápidamente. De hecho, a lo largo de las últimas décadas se han diseñado muchas nanoterapias como alternativa o mejora de las terapias ya existentes contra el cáncer y contra las enfermedades infecciosas principalmente. Una de ellas, la terapia fototérmica, tiene como finalidad el aprovechar el calor emitido por algunos agentes fototérmicos al absorber luz en el infrarrojo cercano (NIR), para poder así destruir células cancerígenas por ablación térmica. Por otro lado, la croconaina es una molécula ya estudiada como agente fotosensibilizante por su dualidad estructural y de absorbancia frente a cambios de pH, presentando una importante absorción en 800 nm cuando se encuentra en medio ácido (pH 5). Esta característica resulta interesante para una terapia fototérmica más segura y efectiva que solo permite la inactivación de las células cuando se encuentra en su interior (ya que algunos compartimentos intracelulares, endosomas, son ácidos) pues el medio extracelular es ligeramente alcalino. En este trabajo se presenta la compleja síntesis de la croconaina incluida en un macrociclo para evitar su posterior agregación y posible quenching de absorbancia. Asimismo, se muestran nuevas encapsulaciones de croconaina que se han llevado a cabo tanto en nanopartículas poliméricas, mediante nanoprecipitación o doble emulsión, como en niosomas. Estas innovadoras encapsulaciones exhiben beneficios frente a los liposomas ya utilizados para encapsular dicha molécula, pues tienen una mayor estabilidad y reducidos costes. También se resalta la dificultad de lograr el comportamiento dual en medio ácido y alcalino de las nanopartículas cargadas de croconaina, debido a la baja difusión del medio en la nanopartícula, impidiendo su cambio de estructura, o bien de la posible baja concentración de molécula encapsulada dentro de las nanopartículas. Todas las síntesis químicas se han caracterizado mediante resonancia magnética nuclear (RMN), y todas las síntesis de nanopartículas se han caracterizado mediante técnicas de visualización ya sea mediante microscopía electrónica de barrido (SEM) o mediante microscopía electrónica de transmisión (TEM). Por otro lado, el comportamiento fototérmico de la croconaina y las nanopartículas se ha evaluado mediante ensayo espectroscópico de absorción UV/VIS y mediante la monitorización de la temperatura al irradiar las muestras con un láser de 808 nm. Finalmente, se ha comprobado la baja citotoxicidad de la molécula en cultivos celulares de monocitos, y su imposible aplicación, a las dosis estudiadas y con las irradiancias usadas, como agente de terapia fototérmica para la ablación de Estafilococos Aureus en infecciones a causa de la alta resistencia térmica de dicha cepa bacteriana

    Focal modulation using rotating phase filters

    Get PDF
    We describe a simple method of refocusing optical systems that is based on the use of two identical phase filters. These filters are divided in annuli and each annulus is divided into sectors with a particular phase value. A controlled focus displacement is achieved by rotating one filter with respect to the other. This displacement is related with the filter parameters. Transverse responses are studied as a function of filters relative position. Furthermore, the experimental set up shows that theoretical prediction fit well with experimental results. The main advantage of this system is the ease of fabrication so that it could be useful in different applications requiring small size, light weight or thin systems, like mobile phone cameras, microscopy tomography, and others

    Combining Genetic and Transcriptomic Approaches to Identify Transporter-Coding Genes as Likely Responsible for a Repeatable Salt Tolerance QTL in Citrus

    Get PDF
    The excessive accumulation of chloride (Cl−) in leaves due to salinity is frequently related to decreased yield in citrus. Two salt tolerance experiments to detect quantitative trait loci (QTLs) for leaf concentrations of Cl−, Na+, and other traits using the same reference progeny derived from the salt-tolerant Cleopatra mandarin (Citrus reshni) and the disease-resistant donor Poncirus trifoliata were performed with the aim to identify repeatable QTLs that regulate leaf Cl− (and/or Na+) exclusion across independent experiments in citrus, as well as potential candidate genes involved. A repeatable QTL controlling leaf Cl− was detected in chromosome 6 (LCl-6), where 23 potential candidate genes coding for transporters were identified using the C. clementina genome as reference. Transcriptomic analysis revealed two important candidate genes coding for a member of the nitrate transporter 1/peptide transporter family (NPF5.9) and a major facilitator superfamily (MFS) protein. Cell wall biosynthesis- and secondary metabolism-related processes appeared to play a significant role in differential gene expression in LCl-6. Six likely gene candidates were mapped in LCl-6, showing conserved synteny in C. reshni. In conclusion, markers to select beneficial Cleopatra mandarin alleles of likely candidate genes in LCl-6 to improve salt tolerance in citrus rootstock breeding programs are provided

    Gaia Focused Product Release: Radial velocity time series of long-period variables

    Get PDF
    Context. The third Gaia Data Release (DR3) provided photometric time series of more than 2 million long-period variable (LPV) candidates. Anticipating the publication of full radial-velocity data planned with Data Release 4, this Focused Product Release (FPR) provides radial-velocity time series for a selection of LPV candidates with high-quality observations. Aims. We describe the production and content of the Gaia catalog of LPV radial-velocity time series, and the methods used to compute the variability parameters published as part of the Gaia FPR. Methods. Starting from the DR3 catalog of LPV candidates, we applied several filters to construct a sample of sources with high-quality radial-velocity measurements. We modeled their radial-velocity and photometric time series to derive their periods and amplitudes, and further refined the sample by requiring compatibility between the radial-velocity period and at least one of the G, GBP, or GRP photometric periods. Results. The catalog includes radial-velocity time series and variability parameters for 9614 sources in the magnitude range 6 ≲ G/mag ≲ 14, including a flagged top-quality subsample of 6093 stars whose radial-velocity periods are fully compatible with the values derived from the G, GBP, and GRP photometric time series. The radial-velocity time series contain a mean of 24 measurements per source taken unevenly over a duration of about three years. We identify the great majority of the sources (88%) as genuine LPV candidates, with about half of them showing a pulsation period and the other half displaying a long secondary period. The remaining 12% of the catalog consists of candidate ellipsoidal binaries. Quality checks against radial velocities available in the literature show excellent agreement. We provide some illustrative examples and cautionary remarks. Conclusions. The publication of radial-velocity time series for almost ten thousand LPV candidates constitutes, by far, the largest such database available to date in the literature. The availability of simultaneous photometric measurements gives a unique added value to the Gaia catalog

    Quantum numbers of the X(3872)X(3872) state and orbital angular momentum in its ρ0Jψ\rho^0 J\psi decay

    Get PDF
    Angular correlations in B+X(3872)K+B^+\to X(3872) K^+ decays, with X(3872)ρ0J/ψX(3872)\to \rho^0 J/\psi, ρ0π+π\rho^0\to\pi^+\pi^- and J/ψμ+μJ/\psi \to\mu^+\mu^-, are used to measure orbital angular momentum contributions and to determine the JPCJ^{PC} value of the X(3872)X(3872) meson. The data correspond to an integrated luminosity of 3.0 fb1^{-1} of proton-proton collisions collected with the LHCb detector. This determination, for the first time performed without assuming a value for the orbital angular momentum, confirms the quantum numbers to be JPC=1++J^{PC}=1^{++}. The X(3872)X(3872) is found to decay predominantly through S wave and an upper limit of 4%4\% at 95%95\% C.L. is set on the fraction of D wave.Comment: 16 pages, 4 figure

    Gaia Early Data Release 3: Summary of the contents and survey properties

    Full text link
    Context. We present the early installment of the third Gaia data release, Gaia EDR3, consisting of astrometry and photometry for 1.8 billion sources brighter than magnitude 21, complemented with the list of radial velocities from Gaia DR2. Aims. A summary of the contents of Gaia EDR3 is presented, accompanied by a discussion on the differences with respect to Gaia DR2 and an overview of the main limitations which are present in the survey. Recommendations are made on the responsible use of Gaia EDR3 results. Methods. The raw data collected with the Gaia instruments during the first 34 months of the mission have been processed by the Gaia Data Processing and Analysis Consortium and turned into this early third data release, which represents a major advance with respect to Gaia DR2 in terms of astrometric and photometric precision, accuracy, and homogeneity. Results. Gaia EDR3 contains celestial positions and the apparent brightness in G for approximately 1.8 billion sources. For 1.5 billion of those sources, parallaxes, proper motions, and the (GBP − GRP) colour are also available. The passbands for G, GBP, and GRP are provided as part of the release. For ease of use, the 7 million radial velocities from Gaia DR2 are included in this release, after the removal of a small number of spurious values. New radial velocities will appear as part of Gaia DR3. Finally, Gaia EDR3 represents an updated materialisation of the celestial reference frame (CRF) in the optical, the Gaia-CRF3, which is based solely on extragalactic sources. The creation of the source list for Gaia EDR3 includes enhancements that make it more robust with respect to high proper motion stars, and the disturbing effects of spurious and partially resolved sources. The source list is largely the same as that for Gaia DR2, but it does feature new sources and there are some notable changes. The source list will not change for Gaia DR3. Conclusions. Gaia EDR3 represents a significant advance over Gaia DR2, with parallax precisions increased by 30 per cent, proper motion precisions increased by a factor of 2, and the systematic errors in the astrometry suppressed by 30-40% for the parallaxes and by a factor ~2.5 for the proper motions. The photometry also features increased precision, but above all much better homogeneity across colour, magnitude, and celestial position. A single passband for G, GBP, and GRP is valid over the entire magnitude and colour range, with no systematics above the 1% leve

    Predicting the onset and persistence of episodes of depression in primary health care. The predictD-Spain study: Methodology

    Get PDF
    Background: The effects of putative risk factors on the onset and/or persistence of depression remain unclear. We aim to develop comprehensive models to predict the onset and persistence of episodes of depression in primary care. Here we explain the general methodology of the predictD-Spain study and evaluate the reliability of the questionnaires used. Methods: This is a prospective cohort study. A systematic random sample of general practice attendees aged 18 to 75 has been recruited in seven Spanish provinces. Depression is being measured with the CIDI at baseline, and at 6, 12, 24 and 36 months. A set of individual, environmental, genetic, professional and organizational risk factors are to be assessed at each follow-up point. In a separate reliability study, a proportional random sample of 401 participants completed the test-retest (251 researcher-administered and 150 self-administered) between October 2005 and February 2006. We have also checked 118,398 items for data entry from a random sample of 480 patients stratified by province. Results: All items and questionnaires had good test-retest reliability for both methods of administration, except for the use of recreational drugs over the previous six months. Cronbach's alphas were good and their factorial analyses coherent for the three scales evaluated (social support from family and friends, dissatisfaction with paid work, and dissatisfaction with unpaid work). There were 191 (0.16%) data entry errors. Conclusion: The items and questionnaires were reliable and data quality control was excellent. When we eventually obtain our risk index for the onset and persistence of depression, we will be able to determine the individual risk of each patient evaluated in primary health care.The research in Spain was funded by grants from the Spanish Ministry of Health (grant FIS references: PI04/1980, PI0/41771, PI04/2450, and PI06/1442), Andalusian Council of Health (grant references: 05/403, 06/278 and 08/0194), and the Spanish Ministry of Education and Science (grant reference SAF 2006/07192). The Malaga sample, as part of the predictD-International study, was also funded by a grant from The European Commission (reference QL4-CT2002-00683)
    corecore