1,437 research outputs found
Dexamethasone Intravitreal Implant for Treatment of Patients with Recalcitrant Macular Edema Resulting from Irvine-Gass Syndrome
PURPOSE:
To evaluate the effectiveness of a single intravitreal injection of dexamethasone implant, over 6 months in patients with recalcitrant CME due to Irvine-Gass syndrome.
METHODS:
Retrospective review of the medical records of nine patients with refractory macular edema (ME) due to Irvine-Gass syndrome, who underwent a single intravitreal injection of dexamethasone implant, Ozurdex, between November 2010 and January 2012, at the Instituto de Microcirurgia Ocular, Barcelona, Spain. All patients underwent a complete ophthalmic evaluation, including best-corrected visual acuity (BCVA) using standardized ETDRS charts, tonometry, fluorescein angiography, and spectral-domain optical coherence tomography with foveal thickness (FT) measurement.
RESULTS:
The mean duration of CME before treatment with Ozurdex was 9.1 months (range, 6-13 months). At baseline, the mean FT was 542.22 ± 134.78 μm. Mean (SD) values of FT did decrease to 350.88 ± 98.71 μm (P = 0.001) at month 1 and 319.22 ± 60.96 μm (P = 0.002) at month 3. Data on the 6-month follow-up showed a mild increase 398.33 ± 127.89 μm (P = 0.031). The mean (SD) change from baseline FT was 191.33 μm (a decrease value of 35%) at month 1, and 223.00 μm (decrease value of 41%) and 143.89 μm (decrease value of 26%) at month 3 and month 6, respectively. The baseline BCVA data were 0.62 ± 0.15 logarithm of the minimum angle of resolution (logMAR). The mean BCVA improved to 0.47 ± 0.21 logMAR (P = 0.008) and 0.37 ± 0.24 logMAR (P = 0.001) after month 1 and month 3, respectively. At the last visit (6-month follow-up), the mean BCVA was 0.37 ± 0.26 logMAR (P = 0.002).
CONCLUSIONS:
In this study, both mean FT and mean BCVA had improved from baseline by 1 month after treatment with a dexamethasone implant, and the improvement remained statistically significant throughout the 6-month study.info:eu-repo/semantics/publishedVersio
Minimization of Feedback Loop Distortions in Digital Predistortion of a Radio-Over-Fiber System with Optimization Algorithms
This article proposes the linearization of an intensity modulation/direct detection radio-over-fiber (RoF) link with feedback loop. The goal is to carry out the predistortion process in a real scenario, in which the output signals are a few kilometers far from the baseband unit (BBU). First, the feedback loop is considered ideal, so the output signals are captured at the remote radio head side. Then, the feedback loop is taken into account, and both the input and output signals are captured at the BBU side. Applying optimization algorithms, such as Fibonacci, Golden, or Powell, it is possible to seek the optimal attenuation value within only a few iterations, which minimizes the distortion of the feedback loop. Experiments are carried out in a RoF system with 10 and 25 km length fiber within the long-Term evolution (LTE) standard. Measured results show how with a proper choice of the attenuation it is possible to reach analogous results regarding to an ideal feedback loop in terms of adjacent channel power ratio, the output signal power and error vector magnitude
DPD Linearization Complexity Reduction of Remote Radio Heads in C-RAN with Radio over Fiber Fronthaul
Radio-over-Fiber (RoF) is a suitable technology for efficiently developing the cloud-RAN concept in Fifth Generation (5G) deployments based on Long Term Evolution Advanced LTE-A. Distortion coming out from the radiofrequency (RF) power amplifier should be taken into account in order to achieve the desired performance at the base station. In this paper, a complexity reduction technique based on a variable degree polynomial predistorter is proposed. The obtained results show that it is possible to achieve a reduction of operations with a penalty of 1.6 dB in ACLR and negligible impact on the EVM
Hydrogen Susceptibility of Nanostructured Bainitic Steels
Abstract
Nanostructured steels with an ultimate tensile strength of 1.6 GPa were produced with austenite content varying from 0 to 35 vol pct. The effect on the mechanical properties was assessed after saturating the steel with hydrogen. Elongation was reduced to 2 to 5 pct and UTS to 65 to 70 pct of prior value. Thermal desorption measurements confirmed the higher solubility of hydrogen in the steel with higher austenite content. The level of hydrogen saturation was found to correlate to the total area of grain boundaries rather than to the volume fraction of retained austenite.This is the final version of the article. It was first available from Springer via http://dx.doi.org/10.1007/s11661-015-3221-
Efficiency enhancement by reconfigurable matching networks in LINC transmitters
This paper proposes the use of a transmitter based on a linear amplification with nonlinear components (LINC) architecture, in which the reconfigurable matching networks (RMNs) are included. By varying the RMN active cell number, it is possible to change the load impedance at the power amplifier (PA) output, improving the amplifier drain efficiency and therefore the efficiency of the whole system. A long-term evolution (LTE) downlink signal with a bandwidth of 1.4 MHz and a peak-to-average power ratio (PAPR) of 11.48 dB is applied in order to carry out the experiments. Results show that the use of the RMNs in a LINC architecture improves the efficiency at all tested frequencies, especially at 927 MHz reaching an enhancement of 36.50%. Regarding the distortion, the adjacent channel leakage ratio (ACLR) values increase in all cases, with an improvement of 3.5 dB at 958 MHz. Finally, in terms of error vector magnitude (EVM), the proposed architecture offers a value of 1.96% at 927 MHz
Evaluation of potential of high Si high C steel nanostructured bainite for wear and fatigue applications
Investigaciones paleobotánicas en la cuenca central del Duero
El objetivo del trabajo es dar a conocer el estado actual de conocimientos científicos sobre el pasado del paisaje vegetal (Cuaternario final) en los territorios interiores no montanos de la depresión del Duero. Se recogen todos los yacimientos cuyo estudio ya ha concluido así como los que se encuentran en fase de investigación o prospección. Se precisa el tipo de informador en cada caso (polen, carbones, maderas, otros macrorrestos), el rango cronológico conocido hasta el momento así como el grado o proporción de trabajo realizado en cada yacimiento en relación con las previsiones efectuadas. Se aporta una síntesis-resumen de los principales resultados obtenidos hasta el momento y de los aspectos más concluyentes de los mismos en relación con la elaboración de modelos de evolución del paisaje vegetal posteriores al último máximo glacial en la Meseta norte. A nuestro juicio debe destacarse, como uno de los resultados más relevantes, el conocimiento ya afianzado de que los pinares de meseta han sido el elemento más significativo en amplios sectores del sur y este de la cuenca a lo largo de todo o gran parte del Holoceno, circunstancia que contrasta con todas las propuestas de paisaje pretérito (preantrópico) existentes antes de la realización de las prospecciones paleobotánicas
A new XRD method to quantify plate and lath martensites of hardened medium-carbon steel
This paper introduces a new technique to separately measure the volume fraction and tetragonal ratio of co-existing lath and plate martensites in ultrahigh strength steel, and to calculate their different carbon contents. First of all, the two martensites are assumed to have body centre tetragonal lattice structures of different tetragonal ratios. X-ray diffraction is then applied to obtain the overlapping (200) diffraction peak, which is subsequently separated as four sub-peaks using a self-made multiple Gaussian peak-fitting method to allow the measurement of the individual lattice parameters c and a. Finally a modified equation is applied to calculate the carbon contents from the obtained tetragonal ratios. The new technique is then applied to investigate the effect of subsequent tempering on the decarbonisation of the as-quenched martensites.
Keywords: Gaussian peak-fitting, martensite carbon content,
martensite tetragonal ratio, medium-carbon steels, Xray
diffractio
Diseño de redes neuronales con aprendizaje combinado de retropropagación y búsqueda aleatoria progresiva aplicado a la determinación de austenita retenida en aceros TRIP
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