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The optimal absorption of flexural energy by the critical coupling of a locally resonant grating embedded in a thin plate is reported in this work for the reflection and transmission problems. The grating is made of a 1D-periodic array of local resonators. A viscoelastic coating is also placed on top of each resonator to control the intrinsic losses of the system. The scattering matrices for the propagative waves of both problems are obtained by means of the Layered Multiple Scattering Theory and validated by the Finite Element Method. In this work, we find that the perfect absorption can be obtained in the reflection problem and the maximal absorption in the transmission problem is limited to 50% by tuning the losses only. These results agree with the theoretical predictions since the eigenvalues reduce to the reflection coefficient in the reflection problem and only one of the two eigenvalues of the scattering matrix is critically coupled in the transmission problem. These results highlight the adaptability of the critical coupling method to optimize the absorption of locally resonant materials for flexural waves in 2D transmission and reflection problems, and pave the way to the design of resonators for efficient flexural wave absorption. [ABSTRACT FROM AUTHOR]

An Acoustic Black Hole (ABH) is a passive and efficient way to control the flexural vibrations of beams or plates. In its classical form, an ABH consists of a local reduction of the thickness of a structure according to a power law profile, associated with a thin viscoelastic coating placed in the thinnest region. A focalization and a wave trap effect occur, leading to a localized energy dissipation, which induces a local temperature increase. The objective of this paper is twofold. First, the goal is to develop an adequate experimental methodology capable of accurately mapping the small temperature variations induced by the local dissipation mechanism. Second, from the thermal standpoint, the goal is to provide experimental evidence of a local temperature increase associated with a damping effect in the case of an ABH beam. This paper thus describes a new kind of experimental methodology able to provide original data, bringing some new insight into the ABH physical understanding and the analysis of structural damping. [ABSTRACT FROM AUTHOR]

Abstract Despite abundant evidence demonstrating that platelets foster metastasis, anti-platelet agents have low therapeutic potential due to the risk of hemorrhages. In addition, whether platelets can regulate metastasis at the late stages of the disease remains unknown. In this study, we subject syngeneic models of metastasis to various thrombocytopenic regimes to show that platelets provide a biphasic contribution to metastasis. While potent intravascular binding of platelets to tumor cells efficiently promotes metastasis, platelets further support the outgrowth of established metastases via immune suppression. Genetic depletion and pharmacological targeting of the glycoprotein VI (GPVI) platelet-specific receptor in humanized mouse models efficiently reduce the growth of established metastases, independently of active platelet binding to tumor cells in the bloodstream. Our study demonstrates therapeutic efficacy when targeting animals bearing growing metastases. It further identifies GPVI as a molecular target whose inhibition can impair metastasis without inducing collateral hemostatic perturbations.

We report the synthesis and single-crystal X-ray diffraction, magnetic, and luminescence measurements of a novel family of luminescent cage-like tetranuclear silsesquioxanes (PhSiO1.5)8(LnO1.5)4(O)(C5H8O2)6(EtOH)2(CH3CN)2⋅2CH3CN (where Ln = Tb, 1; Tb/Eu, 2; and Gd, 3), featuring seven-coordinated lanthanide ions arranged in a one-capped trigonal prism geometry. Compounds 1 and 2 exhibit characteristic Tb3+ and Tb3+/Eu3+-related emissions, respectively, sensitized by the chelating antenna acetylacetonate (acac) ligands upon excitation in the UV and visible spectral regions. Compound 3 is used to assess the energies of the triplet states of the acac ligand. For compound 1, theoretical calculations on the intramolecular energy transfer and multiphonon rates indicate a thermal balance between the 5D4 Stark components, while the mixed Tb3+/Eu3+ analog 2, with a Tb:Eu ratio of 3:1, showcases intra-cluster Tb3+-to-Eu3+ energy transfer, calculated theoretically as a function of temperature. By utilizing the intensity ratio between the 5D4→7F5 (Tb3+) and 5D0→7F2 (Eu3+) transitions in the range 11–373 K, we demonstrate the realization of a ratiometric luminescent thermometer with compound 2, operating in the range 11–373 K with a maximum relative sensitivity of 2.0% K−1 at 373 K. These findings highlight the potential of cage-like silsesquioxanes as versatile materials for optical sensing-enabled applications.