Análise Numérica e Experimental da Influência de Dispositivos de Ponta de Asa no Perfil Aerodinâmico NACA 23015

Agricultural aviation has peculiar operating characteristic as the low flight altitudes and the need for precise maneuvers in a short time, these aircraft demand high aerodynamic efficiency. An alternative to improve the performance of these aircraft is the use of a wingtip device. The present work presents a numerical-experimental analysis about the influence of the use of wing tip devices in an aerodynamic profile NACA 23015. The analyzes were performed using two angles of attack. The first was 6 °, as the angle of installation of the wing in an aircraft is commonly and the second was 15 °, a value close to the stall angle. The experimental analyzes were performed in an open circuit aerodynamic channel. Numerical analyzes were performed using the Reynolds-Averaged Navier-Stokes (RANS) equations using the k-ω SST turbulence model. The results obtained by the numerical and experimental methods showed similar values, with only differences in the region of minimum pressure being observed. With the addition of the wing tip device, it was possible to observe an increase of approximately 5.5% and 3.0% in aerodynamic efficiency with angles of attack of 6 and 15 degrees respectively, both in numerical analysis and in experimental tests. Therefore, it is possible to conclude that the device developed in this work can be used as an alternative to optimize the aerodynamic performance of aircraft.A aviação agrícola apresenta características peculiares de operação. Devido às baixas altitudes de voo e a necessidade de manobras precisas em um curto espaço de tempo, estas aeronaves demandam uma elevada eficiência aerodinâmica. Uma possível alternativa para aprimorar o desempenho dessas aeronaves é a utilização de dispositivo ponta de asas. O presente trabalho apresenta uma análise numérico-experimental acerca da influência do uso de dispositivos de ponta de asa no perfil aerodinâmico NACA 23015. As análises foram realizadas utilizando dois ângulos de ataque. O primeiro deles foi 6°, por ser comumente o ângulo de instalação da asa em uma aeronave e o segundo foi de 15°, valor este próximo ao ângulo de estol. As análises experimentais foram realizadas em um canal aerodinâmico de circuito aberto. As análises numéricas foram realizadas a partir das equações de Reynolds-Averaged Navier-Stokes (RANS) adotando o modelo de turbulência k-ω SST. Os resultados obtidos pelos métodos numéricos e experimentais apresentaram valores similares, sendo observadas apenas divergências na região de pressão mínima. Com a adição do dispositivo de ponta de asa foi possível observar um acréscimo de aproximadamente 5,5% e 3,0% na eficiência aerodinâmica com ângulos de ataque de 6 e 15 graus respectivamente, tanto nas análises numéricas quanto nos ensaios experimentais. Sendo assim é possível concluir que o dispositivo desenvolvido neste trabalho pode ser utilizado como uma alternativa para a otimização do desempenho aerodinâmico de aeronaves

Protein-Functionalized Nanoparticles Derived from End-Functional Polymers and Polymer Prodrugs for Crossing the Blood-Brain Barrier

International audienc

Oxidative Stress Boosts the Uptake of Cerium Oxide Nanoparticles by Changing Brain Endothelium Microvilli Pattern

Vascular oxidative stress is considered a worsening factor in the progression of Alzheimer’s disease (AD). Increased reactive oxygen species (ROS) levels promote the accumulation of amyloid-β peptide (Aβ), one of the main hallmarks of AD. In turn, Aβ is a potent inducer of oxidative stress. In early stages of AD, the concomitant action of oxidative stress and Aβ on brain capillary endothelial cells was observed to compromise the blood–brain barrier functionality. In this context, antioxidant compounds might provide therapeutic benefits. To this aim, we investigated the antioxidant activity of cerium oxide nanoparticles (CNP) in human cerebral microvascular endothelial cells (hCMEC/D3) exposed to Aβ oligomers. Treatment with CNP (13.9 ± 0.7 nm in diameter) restored basal ROS levels in hCMEC/D3 cells, both after acute or prolonged exposure to Aβ. Moreover, we found that the extent of CNP uptake by hCMEC/D3 was +43% higher in the presence of Aβ. Scanning electron microscopy and western blot analysis suggested that changes in microvilli structures on the cell surface, under pro-oxidant stimuli (Aβ or H2O2), might be involved in the enhancement of CNP uptake. This finding opens the possibility to exploit the modulation of endothelial microvilli pattern to improve the uptake of anti-oxidant particles designed to counteract ROS-mediated cerebrovascular dysfunctions

Reduced Levels of ABCA1 Transporter Are Responsible for the Cholesterol Efflux Impairment in β-Amyloid-Induced Reactive Astrocytes: Potential Rescue from Biomimetic HDLs

The cerebral synthesis of cholesterol is mainly handled by astrocytes, which are also responsible for apoproteins’ synthesis and lipoproteins’ assembly required for the cholesterol transport in the brain parenchyma. In Alzheimer disease (AD), these processes are impaired, likely because of the astrogliosis, a process characterized by morphological and functional changes in astrocytes. Several ATP-binding cassette transporters expressed by brain cells are involved in the formation of nascent discoidal lipoproteins, but the effect of beta-amyloid (Aβ) assemblies on this process is not fully understood. In this study, we investigated how of Aβ1-42-induced astrogliosis affects the metabolism of cholesterol in vitro. We detected an impairment in the cholesterol efflux of reactive astrocytes attributable to reduced levels of ABCA1 transporters that could explain the decreased lipoproteins’ levels detected in AD patients. To approach this issue, we designed biomimetic HDLs and evaluated their performance as cholesterol acceptors. The results demonstrated the ability of apoA-I nanodiscs to cross the blood–brain barrier in vitro and to promote the cholesterol efflux from astrocytes, making them suitable as a potential supportive treatment for AD to compensate the depletion of cerebral HDLs

Oxcarbazepine free or loaded PLGA nanoparticles as effective intranasal approach to control epileptic seizures in rodents

The brain as a target for drug delivery is a challenge in pharmaceutical research. Among the several proposed strategies, the intranasal route represents a good strategy to deliver drugs to the brain. The goal of this study was to investigate the potential use of oxcarbazepine (OXC) to enhance brain targeting efficiency after intranasal (IN) administration. As well as attempting to use as low a dose as possible to obtain therapeutic effect. Our results showed that, after IN administrations, the dose of OXC that was effective in controlling epileptic seizures was 0.5 mg/Kg (1 dose, every 20 min for 1 h) in rodents, confirmed by Cerebral Spinal Fluid (CSF) bioavailability. With the aim of reducing the number of administrations, sustaining drug release and increasing brain targeting, OXC was loaded into poly(lactide-co-glycolide) (PLGA) nanoparticles (NPs). The selected nanoformulation for in vivo studies was obtained re-suspending the freeze-dried and cryo-protected OXC loaded PLGA NPs. The translocation of 1-1'-Dioctadecyl-3,3,3',3'-tetramethylindotricarbocyanine Iodide loaded PLGA NPs, from nose to the brain, was confirmed by Fluorescence Molecular Tomography, which also evidenced an accumulation of NPs in the brain after repeated IN administrations. IN administrations of OXC loaded PLGA NPs reduced the number of administrations to 1over 24 h compared to the free drug thus controlling seizures in rats. Immunohistochemical evaluations (anti-neurofilament, anti-beta tubulin, and anti-caspase3) demonstrated a neuroprotective effect of OXC PLGA NPs after 16 days of treatment. These encouraging results confirmed the possibility of developing a novel non-invasive nose to brain delivery system of OXC for the treatment of epilepsy

The synergistic effect of chlorotoxin-mApoE in boosting drug-loaded liposomes across the BBB

International audienc

Oxidative Stress Boosts the Uptake of Cerium Oxide Nanoparticles by Changing Brain Endothelium Microvilli Pattern

Vascular oxidative stress is considered a worsening factor in the progression of Alzheimer's disease (AD). Increased reactive oxygen species (ROS) levels promote the accumulation of amyloid-beta peptide (A beta), one of the main hallmarks of AD. In turn, A beta is a potent inducer of oxidative stress. In early stages of AD, the concomitant action of oxidative stress and A beta on brain capillary endothelial cells was observed to compromise the blood-brain barrier functionality. In this context, antioxidant compounds might provide therapeutic benefits. To this aim, we investigated the antioxidant activity of cerium oxide nanoparticles (CNP) in human cerebral microvascular endothelial cells (hCMEC/D3) exposed to A beta oligomers. Treatment with CNP (13.9 +/- 0.7 nm in diameter) restored basal ROS levels in hCMEC/D3 cells, both after acute or prolonged exposure to A beta. Moreover, we found that the extent of CNP uptake by hCMEC/D3 was +43% higher in the presence of A beta. Scanning electron microscopy and western blot analysis suggested that changes in microvilli structures on the cell surface, under pro-oxidant stimuli (A beta or H2O2), might be involved in the enhancement of CNP uptake. This finding opens the possibility to exploit the modulation of endothelial microvilli pattern to improve the uptake of anti-oxidant particles designed to counteract ROS-mediated cerebrovascular dysfunctions