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Background: Chronic neuroinflammation is one of the hallmarks of late-onset Alzheimer’s disease (AD) dementia pathogenesis. Carrying the Apolipoprotein ε4 (APOE4) allele has been associated with an accentuated response to brain inflammation and increases the risk of AD dementia progression. Among inflammation signaling pathways, aberrant eicosanoid activation plays a prominent role in neurodegeneration. Methods: Using brains from the Religious Order Study (ROS), this study compared measures of brain eicosanoid lipidome in older persons with AD dementia to age-matched controls with no cognitive impairment (NCI), stratified by APOE genotype. Results: Lipidomic analysis of the dorsolateral prefrontal cortex demonstrated lower levels of omega-3 fatty acids eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), and DHA-derived neuroprotectin D1 (NPD-1) in persons with AD dementia, all of which associated with lower measures of cognitive function. In persons with dementia. A significant interaction was observed between carrying the APOE4 allele and higher levels of both pro-inflammatory lipids and pro-resolving eicosanoid lipids on measures of cognitive performance and on neuritic plaque burden. Furthermore, analysis of lipid metabolism pathways implicated activation of calcium dependent phospholipase A2 (cPLA2), 5-lipoxygenase (5-LOX) and soluble epoxide hydrolase (sEH) enzymes. Conclusion: These findings implicate activation of the eicosanoid lipidome in the chronic unresolved state of inflammation in AD dementia, that is increased in carriers of the APOE4 allele, and identify potential therapeutic targets for resolving this chronic inflammatory state.

An important challenge for current naval research is the modernization of battleships. Their target detection system must be increasingly efficient and they must be increasingly undetectable. Due to turbulent flows and bubbles, ship wakes are a detectable acoustic signature and ship bow waves disturb sonar detection. In this work, we study sound propagation through bubble clouds in water. We have developed an experimental set‐up which permits us to acquire, in synchronization, acoustical signals and optical images. The phenomenon of bubble monopole resonance in very low frequency, related to bubble size, provokes effects of strong sound damping and sound speed dispersion. These experimental results, related to theoretical results, permit to estimated sizes and concentrations of bubbles. The acquired bubble images permit to know the real bubble sizes and concentrations, in order to correlate with the experimental acoustical results. Air bubbles are generated with a high pressure water jet introduced into t...

Commander and Prosperetti works [J. Acoust. Soc. Am. 85, 732–746 (1989)] show that an acoustic wave, propagating in a bubbly water, is very strongly damped and its phase speed is disturbed for bubble resonance frequency neighboring. In relation to our experimental results, numerical results obtained with these analytical works are presented. Experiments are realized in a large water‐filled tank. A frequency modulated burst, generated with broadband transducers of central frequency 100, 200, and 500 kHz, propagates through the bubble cloud obtained by a high pressure water jet. Our measurements show simultaneously, after the stop of jet, a strong damping of acoustic signal and a small change of its phase speed. After some minutes, this signal gets back progressively its initial amplitude and phase speed values. One can notice that the acoustic signal amplitude and phase speed are not identical in all emission frequency domain. To explain this phenomenon, we assume the existence of frequency band gaps related to the multiple scattering from the bubble cloud. [Work supported by Bassin d’Essais des Carenes (France).]