Study for pediatric protocol optimization in chest CT scan

Radiological exams are increasingly used in clinic for diagnostic analysis of different types of pathologies. These exams are associated with a dose that is received by the patient. In addition, the risks in exposure to ionizing radiation are different according to the group which the individual belongs. According to age, the group of children is more radiosensitive than adults. In this work we have obtained values of the air-weighted kerma index for chest scans studies in a General Electric Computed Tomography (CT) scanner model Discovery with 64-channels. Using an adult protocol, two scans have been performed, one using a cylinder standard PMMA phantom while the second one has used an oblong chest phantom designed for a two year old pediatric patient. Furthermore, other protocols have been selected with a constant voltage but changing the X-ray tube current and maintaining the image quality in order to obtain a reduction in the received dose by the pediatric patient. The use of the adult protocol in the child phantom has an air-weighted kerma index of 89.5% greater than the kerma index using the adult phantom. Due small patients receive higher doses; the use of specific protocols for children is important for the dose reduction in CT tests. An optimized pediatric chest protocol is presented, obtaining as a result dose reduction compared with the adult protocol of 62.2%. Because of different CT scanners characteristics and in order to optimize protocols regard to dose and diagnostic image quality, it is necessary to use pediatric phantoms in health centers

Caracterización de la composición lignocelulósica y lípidos residuales en racimos de frutos vacíos del procesado de aceite de palma

Empty fruit bunches (EFBs) are an agro-industrial residue discarded in the environment when the fresh palm fruits are removed for oil extraction. EFBs are abundant in palm-oil-producing countries and cause environmental problems. Besides their content in lignocellulosic, EFBs also contain amounts of residual lipids from the separation process. Because the palm fruit has two main types of oil from the pulp (palm oil) or the seeds (kernal oil), the residual EFBs lipids may have different compositions. Thus, this work aimed at characterizing the lignocellulosic content and the residual lipids in two EFBs from different palm oil producers. The EFBs were classified as Type 1 and Type 2 according to their source. The results showed that Type 1 EFBs had higher lignocellulosic and fatty acid compositions, similar to palm and kernel oils, while Type 2 EFBs had lower lignocellulosic content and fatty acid composition, similar to palm oil.Los racimos de fruta vacíos (EFBs, por sus siglas en inglés) son un residuo agroindustrial que se desecha cuando se extraen las frutas frescas de palma para extraer el aceite. Los EFBs abundan en los países productores de aceite de palma, lo que genera problemas ambientales. Además de su contenido lignocelulósicos, EFBs también contiene una cantidad de lípidos residuales del proceso de separación. Debido a que la fruta de la palma tiene dos tipos principales de aceite, los de la pulpa (aceite de palma) o de las semillas (aceite de grano), los lípidos residuales de EFBs pueden tener diferentes composiciones. Por lo tanto, este trabajo tuvo como objetivo caracterizar el contenido lignocelulósico y los lípidos residuales en EFBs de diferentes productores de aceite de palma. Los EFBs se clasificaron como Tipo 1 y Tipo 2 según su fuente. Los resultados mostraron que el EFBs tipo 1 tenía una mayor composición lignocelulósica y de ácidos grasos similar a los aceites de palma y de grano, mientras que el EFBs tipo 2 tenía un contenido lignocelulósico inferior y una composición de ácidos grasos similar al aceite de palma

Modelling spectral and timing properties of accreting black holes: the hybrid hot flow paradigm

The general picture that emerged by the end of 1990s from a large set of optical and X-ray, spectral and timing data was that the X-rays are produced in the innermost hot part of the accretion flow, while the optical/infrared (OIR) emission is mainly produced by the irradiated outer thin accretion disc. Recent multiwavelength observations of Galactic black hole transients show that the situation is not so simple. Fast variability in the OIR band, OIR excesses above the thermal emission and a complicated interplay between the X-ray and the OIR light curves imply that the OIR emitting region is much more compact. One of the popular hypotheses is that the jet contributes to the OIR emission and even is responsible for the bulk of the X-rays. However, this scenario is largely ad hoc and is in contradiction with many previously established facts. Alternatively, the hot accretion flow, known to be consistent with the X-ray spectral and timing data, is also a viable candidate to produce the OIR radiation. The hot-flow scenario naturally explains the power-law like OIR spectra, fast OIR variability and its complex relation to the X-rays if the hot flow contains non-thermal electrons (even in energetically negligible quantities), which are required by the presence of the MeV tail in Cyg X-1. The presence of non-thermal electrons also lowers the equilibrium electron temperature in the hot flow model to <100 keV, making it more consistent with observations. Here we argue that any viable model should simultaneously explain a large set of spectral and timing data and show that the hybrid (thermal/non-thermal) hot flow model satisfies most of the constraints.Comment: 26 pages, 13 figures. To be published in the Space Science Reviews and as hard cover in the Space Sciences Series of ISSI - The Physics of Accretion on to Black Holes (Springer Publisher

Development of a Tool to Measure the Clinical Response to Biologic Therapy in Uncontrolled Severe Asthma: The FEV1, Exacerbations, Oral Corticosteroids, Symptoms Score

Background: There is a lack of tools to quantify the response to monoclonal antibodies (mAbs) holistically in severe uncontrolled asthma patients. Objective: To develop a valid score to assist specialists in this clinical context. Methods: The score was developed in four subsequent phases: (1) elaboration of the theoretical model of the construct intended to be measured (response to mAbs); (2) definition and selection of items and measurement instruments by Delphi survey; (3) weight assignment of the selected items by multicriteria decision analysis using the Potentially All Pairwise RanKings of All Possible Alternatives methodology using the 1000minds software; and (4) face validity assessment of the obtained score. Results: Four core items, with different levels of response for each, were selected: severe exacerbations, oral corticosteroid use, symptoms (evaluated by Asthma Control Test), and bronchial obstruction (assessed by FEV1 percent predicted). Severe exacerbations and oral corticosteroid maintenance dose were weighted most heavily (38% each), followed by symptoms (13%) and FEV1 (11%). Higher scores in the weighted system indicate a better response and the range of responses runs from 0 (worsening) to 100 (best possible response). Face validity was high (intraclass correlation coefficient of 0.86). Conclusions: The FEV1, exacerbations, oral corticosteroids, symptoms score allows clinicians to quantify response in severe uncontrolled asthma patients who are being treated with mAbs