137 research outputs found

    PlanetCam UPV/EHU: a two-channel lucky imaging camera for solar system studies in the spectral range 0.38-1.7 µm

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    This is an author-created, un-copyedited version of an article published in Publications of the Astronomical Society of the Pacific. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it.We present PlanetCam UPV/EHU, an astronomical camera designed fundamentally for high-resolution imaging of Solar System planets using the “lucky imaging” technique. The camera observes in a wavelength range from 380 nm to 1.7 µm and the driving science themes are atmosphere dynamics and vertical cloud structure of Solar System planets. The design comprises two configurations that include one channel (visible wavelengths) or two combined channels (visible and short wave nfrared) working simultaneously at selected wavelengths by means of a dichroic beam splitter. In this paper the camera components for the two configurations are described, as well as camera performance and the different tests done for the precise characterization of its radiometric and astrometric capabilities at high spatial resolution. Finally, some images of solar system objects are presented as well as photometric results and different scientific cases on astronomical targets.Peer ReviewedPostprint (author's final draft

    Análisis de los costes asociados al seguimiento de pacientes con VIH que discontinúan el tratamiento antirretroviral por falta de eficacia o toxicidad inaceptable en España

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    [Abstract] Objective. To assess the use of resources and the costs associated with following up patients infected with the human immunodeficiency virus after discontinuation of an antiretroviral treatment and initiation of a new one due to a lack of effectiveness or unacceptable toxicity, as compared to the costs involved in the routine follow-up of patients on antiretroviral treatment, from the Spanish National Health System perspective. Method. The use of resources (clinical tests, medical visits, and hospital pharmacy visits) associated with following three profiles of patients infected with the human immunodeficiency virus (stable ones, those discontinuing an existing antiretroviral treatment and being switched to a new one due to a lack of effectiveness, and those discontinuing an existing antiretroviral treatment and being switched to a new one due to unacceptable toxicity) was identified, based on clinical practice guidelines and the findings of a multidisciplinary expert panel (n = 5). The experts agreed on the main adverse events leading to discontinuation, classifying them into gastrointestinal, renal, osseous, musculoskeletal, dermatological, hepatic, lipid profile-related, neuropsychiatric and sexual alterations. Unit costs were identified from official healthcare costs databases. The cost (€, 2020) of following up each patient profile was estimated, excluding the cost of the antiretroviral treatment itself, with a time horizon of two years. Results. The per-patient cost of following up stable patients over two years was estimated at €4,148 (tests: €2,293; visits: €1,855). Patient follow-up after discontinuation of an existing antiretroviral treatment and initiation of a different one due to a lack of effectiveness was estimated at €5,434 (tests: €2,777; visits: €2,657). The cost of follow-up after discontinuation of an existing regimen and initiation of a new one due to unacceptable toxicity varied according to the adverse event prompting the switch, ranging from €4,690 for lipid profile dysregulation, to €5,304, for musculoskeletal alterations. In this patient profile, the cost of tests ranged from €2,403 to €3,017, and that of visits from €2,287 to €2,842. Conclusions. The cost associated with following up of patients infected with the human immunodeficiency virus after discontinuation of an existing antiretroviral regimen and initiation of a new one is higher than that of routine follow-up, without taking the cost of drugs into account. The treatment discontinuation rate is a relevant factor when selecting the most appropriate therapy for each patient.[Resumen] Objetivo. Estimar el uso de recursos y costes asociados al seguimiento de pacientes con infección por el virus de la inmunodeficiencia humana tras discontinuación del tratamiento antirretroviral actual debido a falta de efectividad o toxicidad inaceptable y cambio a un nuevo tratamiento antirretroviral, comparado con el seguimiento habitual de los pacientes con tratamiento antirretroviral, desde la perspectiva del Sistema Nacional de Salud español. Método. Se identificó el uso de recursos (pruebas clínicas, visitas médicas, visitas a la farmacia hospitalaria) asociado al seguimiento de pacientes con infección por el virus de la inmunodeficiencia humana en tres perfiles de pacientes (estable, discontinuación y cambio por falta de efectividad, discontinuación y cambio por toxicidad inaceptable), a partir de las guías de práctica clínica y un panel de expertos multidisciplinar (n = 5). Los expertos consensuaron los principales eventos adversos que conducían a la discontinuación, agrupándolos en: alteraciones gastrointestinales, renales, óseas, musculoesqueléticas, dermatológicas, hepáticas y del perfil lipídico, trastornos neuropsiquiátricos y sexuales. Los costes unitarios se identificaron a partir de bases de datos oficiales de costes sanitarios y de la literatura. Se estimó el coste (€, 2020) del seguimiento en cada perfil de paciente, sin incluir el coste derivado del tratamiento antirretroviral, en un horizonte temporal de dos años. Resultados. El coste por paciente a dos años se estimó en 4.148 € (pruebas: 2.293 €; visitas: 1.855 €) para el seguimiento del paciente estable. El seguimiento del paciente tras discontinuación por falta de efectividad y cambio de tratamiento antirretroviral se estimó en 5.434 € (pruebas: 2.777 €; visitas: 2.657 €). El coste del seguimiento tras la discontinuación por toxicidad inaceptable y cambio de tratamiento antirretroviral varió en función del evento adverso que motivó el cambio, oscilando entre 4.690 € para las alteraciones del perfil lipídico, y 5.304 € para las alteraciones musculoesqueléticas. En este perfil de pacientes, las pruebas variaron entre 2.403 € y 3.017 € y las visitas entre 2.287 € y 2.842 €. Conclusiones. El coste asociado al seguimiento del paciente con infección por el virus de la inmunodeficiencia humana tras discontinuación y cambio a un nuevo tratamiento antirretroviral es mayor comparado con el seguimiento habitual, sin tener en cuenta el coste farmacológico. La tasa de discontinuación del tratamiento antirretroviral es un factor relevante a la hora de seleccionar la terapia más adecuada para cada paciente

    Photoluminescent And Self-Assembled Hyaluronic Acid-Zinc Oxide-Ginsenoside Rh2 Nanoparticles And Their Potential Caspase-9 Apoptotic Mechanism Towards Cancer Cell Lines

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    Background: Zinc oxide nanoparticles (ZnO NPs) are used in modern cancer therapy based on their specific target, efficacy, low toxicity and biocompatibility. The photocatalytic performance of Zinc oxide (ZnO) nanocomposites with hyaluronic acid (HA) was used to study anticancer properties against various human cancer cell lines. Methods: Zinc oxide (ZnO) nanocomposites functionalized by hyaluronic acid (HA) were prepared by a co-precipitation method (HA-ZnONcs). The submicron-flower-shaped nanocomposites were further functionalized with ginsenoside Rh2 by a cleavable ester bond via carbodiimide chemistry to form Rh2HAZnO. The physicochemical behaviors of the synthesized ZnO nanocomposites were characterized by various analytical and spectroscopic techniques. We carried out 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) assay to evaluate the toxicity of Rh2HAZnO in various human cancer cells (A549, MCF-7, and HT29). Furthermore, to confirm the apoptotic effects of Rh2HAZnO and to determine the role of the Caspase-9/p38 MAPK pathways by various molecular techniques such as RT-PCR and Western blotting. Furthermore, Rh2HAZnO induced morphological changes of these cell lines, mainly intracellular reactive oxygen species (ROS) were observed by ROS staining and nucleus by Hoechst staining. Results: We confirmed that Rh2HAZnO exhibits the anti-cancer effects on A549 lung cancer, HT29 colon cancer, and MCF7 breast cancer cells. Moreover, intracellular reactive oxygen species (ROS) were observed in three cancer cell lines. Rh2HAZnO induced apoptotic process through p53-mediated pathway by upregulating p53 and BAX and downregulating BCL2. Specifically, Rh2HAZnO induced activation of cleaved PARP (Asp214) in A549 lung cancer cells and upregulated Caspase-9/phosphorylation of p38 MAPK in other cell lines (HT29 and MCF-7). Furthermore, Rh2HAZnO induced morphological changes in the nucleus of these cell lines. Conclusion: These results suggest that the potential anticancer activity of novel Rh2HAZnO nanoparticles might be linked to induction of apoptosis through the generation of ROS by activation of the Caspase-9/p38 MAPK pathway

    The dark nature of GRB 051022 and its host galaxy

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    We present multiwavelength (X-ray/optical/near-infrared/millimetre) observations of GRB 051022 between 2.5 hours and ~1.15 yr after the event. It is the most intense gamma-ray burst (~ 10^-4 erg cm^-2) detected by HETE-2, with the exception of the nearby GRB 030329. Optical and near infrared observations did not detect the afterglow despite a strong afterglow at X-ray wavelengths. Millimetre observations at Plateau de Bure (PdB) detected a source and a flare, confirming the association of this event with a moderately bright (R = 21.5) galaxy. Spectroscopic observations of this galaxy show strong [O II], Hbeta and [O III] emission lines at a redshift of 0.809. The spectral energy distribution of the galaxy implies Av (rest frame) = 1.0 and a starburst occuring ~ 25 Myr ago, during which the star-forming-rate reached >= 25 Msun/yr. In conjunction with the spatial extent (~ 1'') it suggests a very luminous (Mv = - 21.8) blue compact galaxy, for which we also find with Z Zsun. The X-ray spectrum shows evidence of considerable absorption by neutral gas with NH, X-ray = 3.47(+0.48/-0.47) x 10^22 cm^-2 (rest frame). Absorption by dust in the host galaxy at z = 0.809 certainly cannot account for the non-detection of the optical afterglow, unless the dust-to-gas ratio is quite different than that seen in our Galaxy (i.e. large dust grains). It is likely that the afterglow of the dark GRB 051022 was extinguished along the line of sight by an obscured, dense star forming region in a molecular cloud within the parent host galaxy. This galaxy is different from most GRB hosts being brighter than L* by a factor of 3. We have also derived a SFR ~ 50 Msun/yr and predict that this host galaxy will be detected at sub-mm wavelengths.Comment: 7 Pages, 7 figures. Accepted in Astronomy and Astrophysic

    KOBEsim: A Bayesian observing strategy algorithm for planet detection in radial velocity blind-search surveys

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    Context. Ground-based observing time is precious in the era of exoplanet follow-up and characterization, especially in high-precision radial velocity instruments. Blind-search radial velocity surveys thus require a dedicated observational strategy in order to optimize the observing time, which is particularly crucial for the detection of small rocky worlds at large orbital periods. Aims. We developed an algorithm with the purpose of improving the efficiency of radial velocity observations in the context of exoplanet searches, and we applied it to the K-dwarfs Orbited By habitable Exoplanets experiment. Our aim is to accelerate exoplanet confirmations or, alternatively, reject false signals as early as possible in order to save telescope time and increase the efficiency of both blind-search surveys and follow-up of transiting candidates. Methods. Once a minimum initial number of radial velocity datapoints is reached in such a way that a periodicity starts to emerge according to generalized Lomb-Scargle periodograms, that period is targeted with the proposed algorithm, named KOBEsim. The algorithm selects the next observing date that maximizes the Bayesian evidence for this periodicity in comparison with a model with no Keplerian orbits. Results. By means of simulated data, we proved that the algorithm accelerates the exoplanet detection, needing 29-33% fewer observations and a 41-47% smaller time span of the full dataset for low-mass planets (mp < 10 M⊕) in comparison with a conventional monotonic cadence strategy. For 20 M⊕ planets we found a 16% enhancement in the number of datapoints. We also tested KOBEsim with real data for a particular KOBE target and for the confirmed planet HD 102365 b. These two tests demonstrate that the strategy is capable of speeding up the detection by up to a factor of 2 (i.e., reducing both the time span and number of observations by half).14 página

    The shallow-decay phase in both optical and x-ray afterglows of Swift GRB 090529A: Energy injection into a wind-type medium?

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    The energy injection model is usually proposed to interpret the shallow-decay phase in Swift GRB X-ray afterglows. However, very few GRBs have simultaneous signatures of energy injection in their optical and X-ray afterglows. Here, we report optical observations of GRB 090529A from 2000 sec to 106\sim10^6 sec after the burst, in which an achromatic decay is seen at both wavelengths. The optical light curve shows a decay from 0.37 to 0.99 with a break at 105\sim10^5 sec. In the same time interval, the decay indices of the X-ray light curve changed from 0.04 to 1.2. Comparing these values with the closure relations, the segment after 3×104\times10^{4} sec is consistent with the prediction of the forward shock in an ISM medium without any energy injection. The shallow-decay phase between 2000 to 3×104\times10^{4} sec could be due to the external shock in a wind-type-like medium with an energy injection under the condition of νo<νc<νx\nu_o < \nu_c < \nu_x. However, the constraint of the spectral region is not well consistent with the multi-band observations. For this shallow-decay phase, other models are also possible, such as energy injection with evolving microphysical parameters, or a jet viewed off-axis,etc.Comment: 19pages,2gigures, accepted by MNRA

    Nutrient scavenging-fueled growth in pancreatic cancer depends on caveolae-mediated endocytosis under nutrient-deprived conditions

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    Pancreatic ductal adenocarcinoma (PDAC) is characterized by its nutrient-scavenging ability, crucial for tumor progression. Here, we investigated the roles of caveolae-mediated endocytosis (CME) in PDAC progression. Analysis of patient data across diverse datasets revealed a strong association of high caveolin-1 (Cav-1) expression with higher histologic grade, the most aggressive PDAC molecular subtypes, and worse clinical outcomes. Cav-1 loss markedly promoted longer overall and tumor-free survival in a genetically engineered mouse model. Cav-1-deficient tumor cell lines exhibited significantly reduced proliferation, particularly under low nutrient conditions. Supplementing cells with albumin rescued the growth of Cav-1-proficient PDAC cells, but not in Cav-1-deficient PDAC cells under low glutamine conditions. In addition, Cav-1 depletion led to significant metabolic defects, including decreased glycolytic and mitochondrial metabolism, and downstream protein translation signaling pathways. These findings highlight the crucial role of Cav-1 and CME in fueling pancreatic tumorigenesis, sustaining tumor growth, and promoting survival through nutrient scavenging

    Multi-wavelength observations of the energetic GRB 080810: detailed mapping of the broadband spectral evolution

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    GRB 080810 was one of the first bursts to trigger both Swift and the Fermi Gamma-ray Space Telescope. It was subsequently monitored over the X-ray and UV/optical bands by Swift, in the optical by ROTSE and a host of other telescopes and was detected in the radio by the VLA. The redshift of z= 3.355 +/- 0.005 was determined by Keck/HIRES and confirmed by RTT150 and NOT. The prompt gamma/X-ray emission, detected over 0.3-10^3 keV, systematically softens over time, with E_peak moving from ~600 keV at the start to ~40 keV around 100 s after the trigger; alternatively, this spectral evolution could be identified with the blackbody temperature of a quasithermal model shifting from ~60 keV to ~3 keV over the same time interval. The first optical detection was made at 38 s, but the smooth, featureless profile of the full optical coverage implies that this originated from the afterglow component, not the pulsed/flaring prompt emission. Broadband optical and X-ray coverage of the afterglow at the start of the final X-ray decay (~8 ks) reveals a spectral break between the optical and X-ray bands in the range 10^15 - 2x10^16 Hz. The decay profiles of the X-ray and optical bands show that this break initially migrates blueward to this frequency and then subsequently drifts redward to below the optical band by ~3x10^5 s. GRB 080810 was very energetic, with an isotropic energy output for the prompt component of 3x10^53 erg and 1.6x10^52 erg for the afterglow; there is no evidence for a jet break in the afterglow up to six days following the burst.Comment: 15 pages, 9 figures, 4 in colour. Accepted for publication in MNRA

    GRB 060121: Implications of a Short/Intermediate Duration Gamma-Ray Burst at High Redshift

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    Since the discovery of the first short-hard gamma-ray burst afterglows in 2005, the handful of observed events have been found to be embedded in nearby (z < 1), bright underlying galaxies. We present multiwavelength observations of the short-duration burst GRB 060121, which is the first observed to clearly outshine its host galaxy (by a factor >10^2). A photometric redshift for this event places the progenitor at a most probable redshift of z = 4.6, with a less probable scenario of z = 1.7. In either case, GRB 060121 could be the farthermost short-duration GRB detected to date and implies an isotropic-equivalent energy release in gamma-rays comparable to that seen in long-duration bursts. We discuss the implications of the released energy on the nature of the progenitor. These results suggest that GRB 060121 may belong to a family of energetic short-duration events, lying at z > 1 and whose optical afterglows would outshine their host galaxies, unlike the first short-duration GRBs observed in 2005. The possibility of GRB 060121 being an intermediate duration burst is also discussed.Comment: 4 pages, 4 figures. Submitted to ApJ
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