Pulmonary hypertension of the newborn (PHN) constitutes a critical condition with severe cardiovascular and neurological consequences. One of its main causes is hypoxia during gestation, and thus, it is a public health concern in populations living above 2500 m. Although some mechanisms are recognized, the pathophysiological facts that lead to PHN are not fully understood, which explains the lack of an effective treatment. Oxidative stress is one of the proposed mechanisms inducing pulmonary vascular dysfunction and PHN. Therefore, we assessed whether melatonin, a potent antioxidant, improves pulmonary vascular function. Twelve newborn sheep were gestated, born, and raised at 3600 meters. At 3 days old, lambs were catheterized and daily cardiovascular measurements were recorded. Lambs were divided into two groups, one received daily vehicle as control and another received daily melatonin (1 mg/kg/d), for 8 days. At 11 days old, lung tissue and small pulmonary arteries (SPA) were collected. Melatonin decreased pulmonary pressure and resistance for the first 3 days of treatment. Further, melatonin significantly improved the vasodilator function of SPA, enhancing the endothelial- and muscular-dependent pathways. This was associated with an enhanced nitric oxide-dependent and nitric oxide independent vasodilator components and with increased nitric oxide bioavailability in lung tissue. Further, melatonin reduced the pulmonary oxidative stress markers and increased enzymatic and nonenzymatic antioxidant capacity. Finally, these effects were associated with an increase of lumen diameter and a mild decrease in the wall of the pulmonary arteries. These outcomes support the use of melatonin as an adjuvant in the treatment for PHN.
In this paper, an adaptive scene-based nonuniformity correction methodology for infrared image sequences is developed. The method estimates detector parameters and carry out the non-uniformity correction based on the recursive least square filter approach, with adaptive supervision. The key advantage of the method is based in its capacity for estimate detectors parameters, and then compensate for fixed-pattern noise in a frame by frame basics. The ability of the method to compensate for nonuniformity is demonstrated by employing several infrared video sequences obtained using two infrared cameras.
Continuous measurement of partial discharge plays a vital role in monitoring the status of high voltage equipment in electricity substations. This requires a comprehensive supervisory system to detect, monitor, collect and locate partial discharge activities. Most of the sensors developed so far require a dedicated software and hardware platform to integrate them into a system. A comprehensive supervisory system is proposed and designed that integrates broadband radiometric sensors into a robust wireless network. The network is easy to install and reconfigure. Partial discharge activities are collected by the sensors and transferred to a central database where processed to provide monitoring, visualisation and localisation of the partial discharge sources.
In this paper, a technique to improve the convergence and to reduce the ghosting artifacts of a previously developed adaptive scenebased nonuniformity correction method is presented. The nonuniformity correction method estimates detector parameters based on the recursive least square filter approach. We propose, three parameters to reduce ghosting artifacts and to speed up the convergence of such method by using only the read-out data. The parameters proposed are based in identify global motion between consecutive frames as well as evaluate the main assumption used in the previous method in the uncertainty on the input infrared irradiance. The ability of the method to compensate for nonuniformity and reducing ghosting artifacts is demonstrated by employing several infrared video sequences obtained using two infrared cameras.
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