111 research outputs found

    Quantification of phase content in TiO2 thin films by Raman spectroscopy

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    Recently, it has been reported that TiO2 with mixture of phases (anatase/rutile) exhibit higher photocatalytic activity than TiO2 with pure anatase phase. Therefore, the production and correct quantification of the ratio of phases becomes an important task. In this work, anatase TiO2 thin films were obtained by the DC reactive magnetron sputtering technique. TiO2 with mixture of phases (anatase/rutile) were prepared by thermal annealing of the as-deposited thin films. The value of the anatase/rutile ratio in the titanium dioxide thin films was estimated using Raman spectroscopy. Additionally, it is reported the dependence of the bandgap of the TiO2 thin films as a function of the anatase/rutile ratio. The band gap of the TiO2 thin films was determined from diffuse reflectance measurements

    Electron evaporation of carbon using a high density plasma

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    High-density plasmas are often used either in the preparation of thin films or for the modification of surfaces; nitriding. However, except for collision-driven chemical reactions the electrons present are not used, although electron bombardment heating of the work piece nearly always occurs. Principally it is the ions and neutrals that are utilised for materials processing. By suitable biasing of a conducting source material the electrons can be extracted from a highdensity low-pressure plasma to such an extent that evaporation of this source material can be achieved. Due to the presence of the plasma and the flux of electrons a large proportion of the evaporant is expected to be ionised. We have used this novel arrangement to prepare thin films of carbon using a resonant high-density argon plasma and a water cooled rod of high purity graphite. Multiple substrates were used both outside of, and immersed in, the plasma. We report the characteristics of the plasma (electron temperature and density, the ion energy and flux, and optical emission spectra), the deposition process (the evaporation rate and ion/neutral ratio), and the film properties (IR and UV/Vis absorption spectra, Raman spectra, elemental analysis, hardness and refractive index

    Understanding the Real Effect of the High-Order Aberrations after Myopic Femto-Lasik

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    In this work we try to understand the real effect of increase in aberrations after Femto-LASIK surgery on the patient’s final visual quality, specifically when the visual acuity measurement is considered. A clinical study with 37 eyes of 20 patients that underwent myopic Femto-LASIK surgery and different personalized eye model simulations were carried out. In clinical study, correlations between pre- and postoperative parameters with visual acuity were analysed. Eye simulations (based on real data) provided simulations of vision quality before and after surgery. Our main results showed a significant increase in aberrations was obtained after surgery; however, no differences were found between the preoperative corrected distance visual acuity (CDVA) and the postoperative uncorrected distance visual acuity (UDVA). This absence of differences in visual quality could be explained by performing different simulations on three eyes that would cover most of the possible clinical situations. Simulations were implemented considering a pupil size of 2.5 mm and the personalized data of each patient. Results showed that final visual acuity (VA) change are determined by the final high-order aberrations (HOAS) and their increase after surgery but measured under photopic conditions. In conclusion, customized analysis of higher-order aberrations in scotopic pupils better predicts patient visual acuity after Lasik surgery.This work was supported by the “Generalitat Valenciana” of Spain (project AICO/2021/130)

    Hyperspectral detection of citrus damage with Mahalanobis kernel classifier

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    Presented is a full computer vision system for the identification of post-harvest damage in citrus packing houses. The method is based on the combined use of hyperspectral images and the Mahalanobis kernel classifier. More accurate and reliable results compared to other methods are obtained in several scenarios and acquired images

    A 3D TLM code for the study of the ELF electromagnetic wave propagation in the Earth's atmosphere

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    The interest in the study of electromagnetic propagation through planetary atmospheres is briefly discussed. Special attention is devoted to extremely-low-frequency fields in the Earth's atmosphere for its global nature and possible applications to climate monitoring studies among others. In the Earth's case, the system can be considered as a spherical electromagnetic shell resonator in which two concentric and large conducting spheres with a radius around 6300 km are separated by a very small distance of around 100 km, the atmosphere height. A numerical solution using the Transmission Line Method is proposed. The classical spherical-coordinate description is easy to use, however, the important difference in the dimensions along the three coordinate directions causes high numerical dispersion in the results. A Cartesian scheme with equal node size for all directions is used to reduce this undesired dispersion. A pre-processing stage is the key point introduced to lessen the resulting high demand of memory and time calculation and make the solution feasible. A parallelized Fortran code together with pre- and post-processing Python programs to ease the user interface are provided with this work. Details on the Fortran code and the Python modules are included both in the paper and the source codes to allow the use and modifications by other researchers interested in electromagnetic propagation through planetary atmospheres. The program allows calculation of the time evolution of the electromagnetic field at any point in the atmosphere. It includes the possibility of considering multiple time-dependent sources and different homogeneous and inhomogeneous conductivity profiles to model different situations. Profiles to study day-night asymmetries or locally perturbed profiles which have been attributed to earthquakes in the literature are implemented, for instance.MCIN/AEI 10.13039/501100011033 (grant PID 2020-112805 GA-I00)Grant PID 2020-112805 GA-I00 funded by MCIN/AEI/10.13039/ 50110001103

    Simulated observations of star formation regions: infrared evolution of globally collapsing clouds

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    The direct comparison between hydrodynamical simulations and observations is needed to improve the physics included in the former and test biases in the latter. Post-processing radiative transfer and synthetic observations are now the standard way to do this. We report on the first application of the \texttt{SKIRT} radiative transfer code to simulations of a star-forming cloud. The synthetic observations are then analyzed following traditional observational workflows. We find that in the early stages of the simulation, stellar radiation is inefficient in heating dust to the temperatures observed in Galactic clouds, thus the addition of an interstellar radiation field is necessary. The spectral energy distribution of the cloud settles rather quickly after 3\sim3 Myr of evolution from the onset of star formation, but its morphology continues to evolve for 8\sim8 Myr due to the expansion of \textsc{Hii} regions and the respective creation of cavities, filaments, and ridges. Modeling synthetic \textit{Herschel} fluxes with 1- or 2-component modified black bodies underestimates total dust masses by a factor of 2\sim2. Spatially-resolved fitting recovers up to about 70%70\% of the intrinsic value. This ``missing mass'' is located in a very cold dust component with temperatures below 1010 K, which does not contribute appreciably to the far-infrared flux. This effect could bias real observations if such dust exists in large amounts. Finally, we tested observational calibrations of the SFR based on infrared fluxes and concluded that they are in agreement when compared to the intrinsic SFR of the simulation averaged over 100\sim100 Myr

    Prediction of sustained remission of chronic hepatitis C after a 12-month course of alfa interferon

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    alpha-Interferon therapy normalizes aminotransferase levels in approximately 50% of the patients with chronic hepatitis C, but post-therapy relapses are common and predictive factors of sustained response remain largely unknown. We retrospectively assessed several parameters as predictors of sustained remission after a 12-month course of lymphoblastoid alpha-interferon: the Knodell histological activity index, serum levels of procollagen type III peptide, serum HCV-RNA, anti-alpha-interferon antibodies, and anti-HCV antibodies (C-100-3), all at month 12. Thirty-seven patients were studied. Fourteen patients were non-responders (38%), 15 patients experienced a sustained response (40.5%) and eight patients responded similarly but relapsed after alpha-interferon withdrawal (21.5%). A decrease in the histological activity index above 5, normalization of procollagen type III peptide levels (< 12 ng/ml) and the absence of viremia after treatment were all significantly associated with a sustained response (p = 0.008, p = 0.007 and p = 0.037, respectively). Anti-interferon antibodies were detected in only one non-responder patient. Anti-C-100-3 antibodies became undetectable at month 12 in 5 of the 15 sustained responders. The best prediction of sustained response was obtained from the three variables independent of multivariate analysis according to the following equation: F = 0.872 + 0.067 x K (decrease of histological index) -0.052 x P (procollagen type III peptide levels at month 12) -0.28 x R (HCV-RNA at month 12; R = 2 when present and R = 1 when absent). A score higher than 0 predicted sustained remission with a 100% sensitivity and specificity in this series of patients

    Differentially Deregulated MicroRNAs as Novel Biomarkers for Neoplastic Progression in Ulcerative Colitis.

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    INTRODUCTION: Colorectal cancer (CRC) is a potentially life-threatening complication of long-standing ulcerative colitis (UC). MicroRNAs (miRNA) are epigenetic regulators that have been involved in the development of UC-associated CRC. However, their role as potential mucosal biomarkers of neoplastic progression has not been adequately studied. METHODS: In this study, we analyzed the expression of 96 preselected miRNAs in human formalin-fixed and paraffin-embedded tissue of 52 case biopsies (20 normal mucosa, 20 dysplasia, and 12 UC-associated CRCs) and 50 control biopsies (10 normal mucosa, 21 sporadic adenomas, and 19 sporadic CRCs) by using Custom TaqMan Array Cards. For validation of deregulated miRNAs, we performed individual quantitative real-time polymerase chain reaction in an independent cohort of 50 cases (13 normal mucosa, 25 dysplasia, and 12 UC-associated CRCs) and 46 controls (7 normal mucosa, 19 sporadic adenomas, and 20 sporadic CRCs). RESULTS: Sixty-four miRNAs were found to be differentially deregulated in the UC-associated CRC sequence. Eight of these miRNAs were chosen for further validation. We confirmed miR-31, -106a, and -135b to be significantly deregulated between normal mucosa and dysplasia, as well as across the UC-associated CRC sequence (all P < 0.01). Notably, these miRNAs also confirmed to have a significant differential expression compared with sporadic CRC (all P < 0.05). DISCUSSION: UC-associated and sporadic CRCs have distinct miRNA expression patterns, and some miRNAs indicate early neoplastic progression.This work was funded by grants from the Instituto de Salud Carlos III (PI12/01481; PI19/01050). Project PI19/ 01050 is funded by Instituto de Salud Carlos III (ISCIII) and co funded by the European Union. CIBEREHD is funded by the Insti tuto de Salud Carlos III and Beca Marató de TV3 (201932-30). Parts of this work were also supported by the Xarxa de Bancs de Tumors de Catalunya sponsored by Pla Director d’Oncología de Catalunya (XBTC) and by the Hospital Clínics Premi Fi de Residència (G.J). None of the funding parties has been involved in collection, analysis, and interpretation of the data
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