Assessment of hydrogen peroxide in breath condensate as an inflammatory marker in asthmatic children

Background: Asthma is a major global public health problem. Airway  inflammation is the primary cause of development and progression of asthma. Activation of inflammatory cells induces a respiratory burst resulting in the production of reactive oxygen species, such as H2O2.Objective: We sought to measure the concentration of H2O2 in exhaled breath condensate in asthmatic children and its correlation to asthmatic triggers, pulmonary function tests, treatment modalities and blood  absolute white blood cell counts.Methods: Fifty asthmatic and 35 healthy children were studied. Their ages ranged from 3-14 years. Exhaled H2O2 was measured using a colorimetric assay.Results: In asthmatic children, there was a significant elevation of the mean H2O2 concentration compared to values in normal subjects( p<0.0001). Bad housing showed significant correlation to asthma severity and to number of acute asthmatic attacks. Basal spirometric pulmonary function tests, mean values showed no significant correlation to the level of H2O2 nor to treatment with inhaled steroids. Similarly, neither asthma severity nor the intake of inhaled steroids did show any significant correlation with H2O2 level.Conclusion: Exhaled H2O2 was found significantly elevated in asthmatic children. Measurement of exhaled H2O2 may help to assess airway inflammation and oxidative stress in asthmatic patients.Keywords: Hydrogen peroxide – H2O2 – exhaled breath condensate – asthma – children – oxidative stress – pulmonary function tests

Neuroprotective Effect of Inhaled Nitric Oxide on Excitotoxic-Induced Brain Damage in Neonatal Rat

BACKGROUND: Inhaled nitric oxide (iNO) is one of the most promising therapies used in neonates. However, little information is known about its impact on the developing brain submitted to excitotoxic challenge. METHODOLOGY/PRINCIPAL FINDINGS: We investigated here the effect of iNO in a neonatal model of excitotoxic brain lesions. Rat pups and their dams were placed in a chamber containing 20 ppm NO during the first week of life. At postnatal day (P)5, rat pups were submitted to intracranial injection of glutamate agonists. At P10, rat pups exposed to iNO exhibited a significant decrease of lesion size in both the white matter and cortical plate compared to controls. Microglia activation and astrogliosis were found significantly decreased in NO-exposed animals. This neuroprotective effect was associated with a significant decrease of several glutamate receptor subunits expression at P5. iNO was associated with an early (P1) downregulation of pCREB/pAkt expression and induced an increase in pAkt protein concentration in response to excitotoxic challenge (P7). CONCLUSION: This study is the first describe and investigate the neuroprotective effect of iNO in neonatal excitotoxic-induced brain damage. This effect may be mediated through CREB pathway and subsequent modulation of glutamate receptor subunits expression

Simulation Assessment of Inlet Parameters and Membrane-Surface-Structure Effects on CO2 Absorption Flux in Membrane Contactors

The management of global carbon dioxide (CO2) emissions is considered one of the main environmental problems facing the modern world. One of the potential techniques for CO2 capture is absorption, using membrane contactor modules. Most of the previous research that dealt with membrane contactor simulations considered the whole membrane surface as the active reaction surface. However, in this paper, a more realistic model of the membrane-contactor module is presented, taking into account the effects of the pore size and surface porosity. CO2 absorption into the monoethanolamine (MEA) solution in hollow fiber membrane-contactor modules was numerically investigated. A computational fluid dynamics simulation was established using essential basic fluid dynamics and mass transfer equations in reactive mode. An algorithmic function was used to present the relations between the CO2 absorption flux and the hollow fiber length, membrane surface pore size, and porosity. The simulation results were compared to previously obtained experimental results without using any fitting parameters, and a good agreement was found with an average error of 8.5%. The validated simulation was then used to predict the effects of the MEA inlet velocity and concentration, the membrane surface pore size, and porosity on the total CO2 absorption flux. A maximum absorption flux of about 1.8 mol/m2·s was achieved at an MEA concentration of 4 M with a pore size of 0.2 microns, a surface porosity of 1%, and an inlet velocity of 0.25 m/s. The extrapolation technique was then used to predict the values of the absorption flux at longer fiber lengths. The concentration profiles around the pores at the gas–liquid contact surface of the membrane were obtained and presented. The proposed model exhibited excellent potential to evaluate the effective reaction surface in hollow fiber membrane contactors. This model could be considered the first step to obtaining accurate predictions of the membrane contactor gas absorption performance based on its surface structure.</jats:p

Genetic Algorithms for the Picker Routing Problem in Multi-block Warehouses

This article presents a genetic algorithm (GA) to solve the picker routing problem in multiple-block warehouses in order to minimize the traveled distance. The GA uses survival, crossover, immigration, and mutation operators, and is complemented by a local search heuristic. The genetic algorithm provides average distance savings of 13.9% when compared with s-shape strategy, and distance savings of 23.3% when compared with the GA with the aisle-by-aisle policy. We concluded that the GA performs better as the number of blocks increases, and as the percentage of picking locations to visit decreases. © 2019, Springer Nature Switzerland AG