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Highlights • Dynamic homogenized model derived by micro-macro asymptotic analysis of ribbed plate with inner resonance. • Explicit and analytical expressions of effective parameters associated with unconventional dispersion in bending and torsion. • Clear understanding of the different branches of dispersion diagram, in terms of flexural and torsional waves and of guided waves. • Good agreement with numerical method based on WFEM (Wave Finite Element Method) approach. • Easy-to-use theoretical framework for engineering purposes and inner resonance panel design. Abstract The dynamic behavior of a periodic ribbed plate with local resonance is investigated. The behavior of the cell made of a beam clamped along a plate edge analyzed through multi-scale asymptotic method enables to derive the governing equations of the effective mechanical behavior. This approach allows obtaining a full homogenized analytical model that provides a relevant representation of the flexural and torsional mechanisms at both global and local scales. The complex dynamic behavior is shown to encompass several mechanisms associated with enriched kinematics. Two types of flexural and torsional waves are evidenced and governed by two distinct differential equations that describes (i) waves where both beam and plate moves, and (ii) guided waves where the plate only is set in motion. The inner resonance of the plate induces unconventional dispersion features, with singularities associated either with the symmetric eigenmodes for the bending waves or the antisymmetric modes for the torsional waves. The guided waves are alternatively related to the symmetric and antisymmetric modes of the bended plate and are propagative above the corresponding eigenfrequencies. The predictions of the homogenized model are successfully compared to numerical calculations conducted using Wave Finite Element based methods, for two realistic examples of ribbed plates. The study provides design rules to tailor ribbed plate panels having specific atypical features in a given frequency range. [ABSTRACT FROM AUTHOR]

Deep dorsal horn neurons are involved in the processing of nociceptive information in the spinal cord. Previous studies revealed a role of the intrinsic bioelectrical properties (plateau potentials) of deep dorsal horn neuron in neuronal hyperexcitability, indicating their function in pain sensitization. These properties were considered to rely on L-type calcium currents. Two different isotypes of L-type calcium channel alpha 1 subunit have been cloned (CaV1.2 and CaV1.3). Both are known to be expressed in the spinal cord. However, no data were available on their subcellular localization. Moreover, possible changes in CaV1.2 and CaV1.3 expression had never been investigated in nerve injury models. Our study provides evidence for a differential expression of CaV1.2 and CaV1.3 subunits in the somato-dendritic compartment of deep dorsal horn neurons. CaV1.2 immunoreactivity is restricted to the soma and proximal dendrites whereas CaV1.3 immunoreactivity is found in the whole somato-dendritic compartment, up to distal dendritic segments. Moreover, these specific immunoreactive patterns are also found in electrophysiologically identified deep dorsal horn neurons expressing plateau potentials. After nerve injury, namely total axotomy or partial nerve ligation, CaV1.2 and CaV1.3 expression undergo differential changes, showing up- and down-regulation, respectively, both at the protein and at the mRNA levels. Taken together, our data support the role of L-type calcium channels in the control of intrinsic biolectrical regenerative properties. Furthermore, CaV1.2 and CaV1.3 subunits may have distinct and specific roles in sensory processing in the dorsal horn of the spinal cord, the former being most likely involved in long-term changes after nerve injury. [ABSTRACT FROM AUTHOR]

• Development of lightweight gearbox housings with improved NVH characteristics. • Introduction of locally resonant metamaterials in gearbox housings to reduce noise radiation. • Numerical results demonstrate significant reductions in sound power radiated with these solutions. • Experimental results confirm the effectiveness of the metamaterial solutions in gearbox housings. Mass reduction of automotive components enhances vehicles' performance and extends their driving range. However, lightweight construction typically leads to noise and vibration issues. Hence, the development of lightweight components must go in tandem with advancements in the field of noise and vibration. This work focuses on the lightweighting of the gearbox housings (GBHs) and on the introduction of vibroacoustic metamaterials to improve their Noise, Vibration, and Harshness (NVH) characteristics. Topology optimization methods were used to reduce the mass of a GBH. Its noise emission was evaluated numerically, before and after the mass reduction. Locally resonant metamaterial (LRM) solutions were applied in the GBH and then tested in numerical simulations. This analysis showed the LRM solutions reduce the emission of noise in the predicted band gaps (BGs), while also providing significant attenuation across the entire frequency spectrum under consideration. The experimental results confirmed the effectiveness of the LRM attenuation concept and the trends observed in the numerical results. Vibration was also attenuated in parts of the GBH where the LRM was not applied. Attenuation of in-plane housing vibration was also observed. The proposed LRM solutions are lightweight, passive and low-cost solutions that can implemented in housings to enhance their NVH characteristics. [ABSTRACT FROM AUTHOR]