Leonardo Sanches

Increasing prevalence of Alzheimer’s disease, driven by population aging, highlights the need to investigate its underlying molecular mechanisms. Within this context, long non-coding RNAs (lncRNAs) have emerged as a key regulatory layer. To advance the understanding of lncRNA dysregulation and function during Alzheimer’s disease progression, we reanalyzed publicly available single-nucleus RNA sequencing (snRNA-seq) datasets. The selected transcriptomic datasets were integrated and subjected to differential expression and genomic co-localization correlation analyses to infer putative cis -regulatory mechanisms. Our results reveal conserved cell-type composition and a shared transcriptional trajectory across brain regions during Alzheimer’s disease progression. In contrast, lncRNAs displayed marked cell-type and context specificity and formed coordinated expression patterns with neighboring genes within defined chromatin contexts. These associations suggest potential cis -regulatory roles and implicate lncRNAs in processes such as synaptic plasticity and maladaptive oligodendrocyte differentiation linked to myelin dysfunction. While these findings are primarily hypothesis-generating, they provide a cross-regional framework and a prioritized set of candidate lncRNAs for future functional investigation in Alzheimer’s disease.

Identification of flutter margins in modern aeroelastic systems is a challenging task due to increased nonlinearities in novel designs, which can result in instabilities occurring below the linear flutter speed. These instabilities pose a significant risk as they may involve multiple stable solutions, such as large-amplitude self-sustained oscillations. The lack of efficient nonlinear bifurcation analysis methods for experimental systems exacerbates the challenges associated with postflutter analysis. This paper presents a data-driven method for predicting flutter instabilities and bifurcation diagrams of an experimental nonlinear 2-degree-of-freedom (2-DOF) airfoil. The approach uses measurement data from the preflutter regime to forecast the postflutter dynamics, eliminating the need for computationally expensive models. This study is the first application of the recently introduced data-driven bifurcation forecasting method to experimental aeroelastic systems. The results show that the proposed method is accurate, with predictions matching the measured behavior of the system. The presented study provides valuable insights into the nonlinear stability and dynamics of experimental airfoils and demonstrates the potential for applicability of this approach in the analysis of experimental systems. The findings have significant implications for online monitoring and evaluation of the nonlinear dynamics of aeroelastic systems in the aerospace industry, where safety is of crucial importance.

Galloping is a self-excited vibration problem that structures immersed in fluid flow can experience. Due to its essential nonlinear phenomena, the structure exhibits limit cycle oscillations (LCOs), which, at high levels, can lead to failure of the systems. This work proposes an investigation of electromagnetic-enhanced nonlinear energy sinks (NES-EH) for the hybrid mitigation of aeroelastic LCOs and energy harvesting. The study focuses on a prismatic bluff body with a linear suspension immersed in the airflow, using classical steady nonlinear modeling for aerodynamic loads. The conventional NES approach is adopted, employing cubic stiffness and linear damping. Additionally, a linear electromagnetic transducer is included in the assembly for the energy harvesting process. By combining the method of multiple scales with the Harmonic Balance Method, analytical solutions are derived to characterize the system's dynamics under the influence of the device. The different response domains and their respective boundaries induced by the NES-EH are characterized based on the bifurcation diagrams. Furthermore, a slow invariant manifold (SIM) characterization is presented for each induced response domain, and its significant features are discussed. Parametric studies are carried out based on bifurcation analyses to assess the effect of NES-EH parameters on the galloping system dynamics, which allows for designing the absorber parameters. The electrical resistance is optimized to maximize the harvested power. The optimal design of NES-EH is then compared with classical energy harvesting solutions for the galloping problem. Additionally, a thorough analysis of the Target Energy Transfer phenomenon is performed.

An expandable and Fire, Smoke, and Toxicity (FST) compliant epoxy foam is proposed as an interesting alternative to Nomex® honeycomb cores for the development of Multi‐Functional Structures (MFS). The paper first analyzes the processing conditions using several experimental techniques as differential scanning calorimetry (DSC), rheology, and expansion in a closed volume in order to evaluate the reaction kinetics, the chemorheological behavior, and the expansion kinetics of the material. The experimental data are used to identify several empirical models describing the material processing behavior and finally plotting the isothermal time–temperature transformation (TTT) diagram. A typical curing cycle for the foam is used to describe the evolution of the material parameters during the curing process. The fully cured foam is then characterized using optical and laser microscopy in order to identify its cell size distribution and density. Quasi‐static and dynamic machines are used to evaluate its mechanical and dynamical properties. The time–temperature equivalence is finally used to plot the master's curves of the material, representing the evolution of the material viscoelastic properties as a function of the frequency.