498 research outputs found
A Versatile Processing Chain for Experimental TanDEM-X Product Evaluation
TanDEM-X is a high-resolution interferometric mission with the main goal of providing a global digital elevation model
(DEM) of the Earth surface by means of single-pass X-band SAR interferometry. It is, moreover, the first genuinely
bistatic spaceborne SAR mission, and, independently of its usual quasi-monostatic configuration, includes many of the
peculiarities of bistatic SAR. An experimental, versatile, and flexible interferometric chain has been developed at DLR
Microwaves and Radar Institute for the scientific exploitation of TanDEM-X data acquired in non-standard configurations.
The paper describes the structure of the processing chain and focusses on some essential aspects of its bistatic part
Optimizing CIGB-300 intralesional delivery in locally advanced cervical cancer
Background:We conducted a phase 1 trial in patients with locally advanced cervical cancer by injecting 0.5 ml of the CK2-antagonist CIGB-300 in two different sites on tumours to assess tumour uptake, safety, pharmacodynamic activity and identify the recommended dose.Methods:Fourteen patients were treated with intralesional injections containing 35 or 70 mg of CIGB-300 in three alternate cycles of three consecutive days each before standard chemoradiotherapy. Tumour uptake was determined using 99 Tc-radiolabelled peptide. In situ B23/nucleophosmin was determined by immunohistochemistry.Results:Maximum tumour uptake for CIGB-300 70-mg dose was significantly higher than the one observed for 35 mg: 16.1±8.9 vs 31.3±12.9 mg (P=0.01). Both, AUC 24h and biological half-life were also significantly higher using 70 mg of CIGB-300 (P<0.001). Unincorporated CIGB-300 diffused rapidly to blood and was mainly distributed towards kidneys, and marginally in liver, lungs, heart and spleen. There was no DLT and moderate allergic-like reactions were the most common systemic side effect with strong correlation between unincorporated CIGB-300 and histamine levels in blood. CIGB-300, 70 mg, downregulated B23/nucleophosmin (P=0.03) in tumour specimens.Conclusion:Intralesional injections of 70 mg CIGB-300 in two sites (0.5 ml per injection) and this treatment plan are recommended to be evaluated in phase 2 studies.Fil: Sarduy, M. R.. Medical-surgical Research Center; CubaFil: García, I.. Centro de Ingeniería Genética y Biotecnología; CubaFil: Coca, M. A.. Clinical Investigation Center; CubaFil: Perera, A.. Clinical Investigation Center; CubaFil: Torres, L. A.. Clinical Investigation Center; CubaFil: Valenzuela, C. M.. Centro de Ingeniería Genética y Biotecnología; CubaFil: Baladrón, I.. Centro de Ingeniería Genética y Biotecnología; CubaFil: Solares, M.. Hospital Materno Ramón González Coro; CubaFil: Reyes, V.. Center For Genetic Engineering And Biotechnology Havana; CubaFil: Hernández, I.. Isotope Center; CubaFil: Perera, Y.. Centro de Ingeniería Genética y Biotecnología; CubaFil: Martínez, Y. M.. Medical-surgical Research Center; CubaFil: Molina, L.. Medical-surgical Research Center; CubaFil: González, Y. M.. Medical-surgical Research Center; CubaFil: Ancízar, J. A.. Centro de Ingeniería Genética y Biotecnología; CubaFil: Prats, A.. Clinical Investigation Center; CubaFil: González, L.. Centro de Ingeniería Genética y Biotecnología; CubaFil: Casacó, C. A.. Clinical Investigation Center; CubaFil: Acevedo, B. E.. Centro de Ingeniería Genética y Biotecnología; CubaFil: López Saura, P. A.. Centro de Ingeniería Genética y Biotecnología; CubaFil: Alonso, Daniel Fernando. Universidad Nacional de Quilmes; ArgentinaFil: Gómez, R.. Elea Laboratories; ArgentinaFil: Perea Rodríguez, S. E.. Center For Genetic Engineering And Biotechnology Havana; Cuba. Centro de Ingeniería Genética y Biotecnología; Cub
The theoretical performance of different algorithms for shift estimation between SAR images
This paper compares several algorithms for shift estimation between SAR images, presenting their performance along with their respective merits and demerits. It shows that there is a parallelism between correlation-based estimators (coherent and incoherent) and two different implementations of split-spectrum methods (Delta-k), both in terms of robustness to interferometric phase variations within the estimation window and in terms of performance. The character of Delta-k estimators is regulated by the amount of multi-looking at interferogram level and is related to the statistical efficiency of the standard estimator for the interferometric phase in case of Gaussian speckle
Impact of Early Non-Invasive Ventilation in Amyotrophic Lateral Sclerosis: A multicenter Randomized Controlled Trial
Respiratory complications; Respiratory insufficiency; SurvivalComplicaciones respiratorias; Insuficiencia respiratoria; SupervivenciaComplicacions respiratòries; Insuficiència respiratòria; SupervivènciaBackground and objective:
Forced vital capacity (FVC) less than 50% of predicted is one of the main parameters used for Non-Invasive Ventilation (NIV) initiation in Amyotrophic Lateral Sclerosis (ALS). Recent studies suggest that higher values of FVC could be considered as a threshold. The aim of this study is to evaluate whether early use of NIV improves the prognosis of ALS patients compared with standard initiation.
Methods:
This is a randomized, parallel, multicenter, open-label, controlled clinical trial, with recruitment at the ALS outpatient multidisciplinary units of six Spanish hospitals. Patients were included when their FVC reached the 75% threshold and were randomized by computer, stratifying by center in an allocation ratio of 1:1 to Early NIV (FVC below 75%) or Standard NIV (FVC below 50%) initiation. The primary outcome was time to death or tracheostomy.
Trial registration number ClinicalTrials.gov: NCT01641965.
Results:
Between May 2012 and June 2014, 42 patients were randomized to two groups, 20 to Early NIV and 22 to Standard NIV initiation. We found differences in survival in favor of the intervention group: an incidence of mortality (2.68 [1.87–5.50] vs. 3.33 [1.34–4.80] person-months) and a median survival (25.2 vs. 19.4 months), although without reaching statistical significance (p = 0.267).
Conclusions:
This trial did not reach the primary endpoint of survival; nevertheless, it is the first Randomized Controlled Trial (RCT) to demonstrate the benefits of early NIV in slowing the decline of respiratory muscle strength and reducing adverse events. Although not all the results reached statistical significance, all the analyzed data favor early NIV. In addition, this study demonstrates good tolerance and compliance with early NIV without quality of sleep impairment. These data reinforce the early respiratory evaluation of ALS patients and NIV initiation with an FVC of around 75%.This study received Health Research Fund (FIS) from Carlos III Health Institute (ISCIII), and a grant from Catalan Society of Pneumology (SOCAP)
Boosting the activity of transition metal carbides towards methane activation by nanostructuring
The interaction of methane with pristine surfaces of bulk MoC and Mo2C is known to be weak. In contrast, a series of X-ray photoelectron spectroscopy (XPS) experiments, combined with thermal desorption mass spectroscopy (TDS), for MoCy (y = 0.5-1.3) nanoparticles supported on Au(111)¿which is completely inert towards CH4¿show that these systems adsorb and dissociate CH4 at room temperature and low CH4 partial pressure. This industrially-relevant finding has been further investigated with accurate density functional theory (DFT) based calculations on a variety of MoCy supported model systems. The DFT calculations reveal that the MoCy/Au(111) systems can feature low C-H bond scission energy barriers, smaller than the CH4 adsorption energy. Our theoretical results for bulk surfaces of Mo2C and MoC show that a simple Brønsted-Evans-Polanyi (BEP) relationship holds for C-H bond scission on these systems. However, this is not the case for methane activation on the MoCy nanoparticles as a consequence of their unique electronic and chemical properties. The discovery that supported molybdenum carbide nanoparticles are able to activate methane at room temperature paves the road towards the design of a new family of active carbide catalysts for methane activation and valorisation, with important implications in climate change mitigation and carbon cycle closure
Analysis of the Retrieval Performance of 2-D Ionospheric Irregularity Maps in the Biomass Mission
Low-frequency synthetic aperture radar (SAR)
images are affected by trans-ionospheric propagation of the
radar waves. The 2-D total electron content (TEC) maps can be
obtained as a product of the ionospheric corrections, allowing for
imaging of ionospheric irregularities at very high resolution and
broader coverage compared to other sensing technologies (such
as Global Navigation Satellite Systems (GNSS) and ionosondes).
We analyze, in this article, the case of the Biomass mission and
characterize the errors in the imaging of the ionosphere resulting
from the calibration algorithms foreseen for its ground processor
prototype: a Faraday rotation (FR)-based and an autofocus (AF)
approach. The analysis relies on a turbulent power law Rino
model for the perturbation of the ionosphere and the spectral
behavior of the calibration algorithms. We also discuss the
suitability of both approaches for image correction in different
scenarios (varying signal-to-noise ratio (SNR) and geographic
location)
Aperture-Dependent Injection of Ionospheric Perturbations Into Simulated SAR Data
This letter presents an algorithm for the introduction of ionospheric disturbances into synthetic aperture radar (SAR) simulations in an aperture-dependent manner using subapertures. Its suitability is compared with other methods that follow the beam-center approximation. The method can be generalized to the injection of all kinds of disturbances, and its two main benefits are the accuracy of the squint angle accommodation inside the synthetic aperture and the possibility of neglecting the static ionosphere assumption. For example, realistic ionospheric disturbance maps (phase and intensity scintillation) are introduced into clutter images simulated for the Biomass mission. In this case, with a typical ionospheric irregularity height of 350 km, the limiting azimuth resolution of the irregularities to be injected is around 337 m
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