Hierarchical rotating-bending metamaterials for simultaneous mechanical vibration suppression and electricity generation

triangular joints between dodecagon unit cells. The proposed structure is additively manufactured from thermoplastic polyurethane (TPU) and further analyzed through finite element analysis (FEA) to explore the deformation mechanisms. Under compression, the high-stiffness triangular joints rotate, inducing bending in adjacent walls, resulting in enhanced stability and quasi-zero-stiffness (QZS) features. Local deformation mechanisms include pure bending, bending combined with shear, and simultaneous shrinkage and expansion. To harness these local deformations, piezo elements integration strategies are proposed. A piezo bender (PB) is adhered to regions experiencing pure bending, lead zirconate titanate (PZT) patches are attached where bending and shear coexist, and piezo stacks are applied at locations with shrinkage and expansion. Experimental results show that before and after gluing piezo elements, the structure exhibits obvious vibration isolation performance, which is independent of the number of unit cells. From the frequency transfer functions, at 10 Hz, where vibration isolation arises, the PB and piezo stack generate power around 8.6 and 2.6 μWg , respectively, while PZT generates power around 11 nW/g. At a higher frequency of 200 Hz, the PB generates a power of 32 nW/g, piezo stack generates a power of 7.6 nW/g, and PZT generates a power of 2.9 nW/g. The proposed hierarchical metamaterials provides multifunctional capabilities, simultaneously isolating vibrations and generating electricity. They facilitate versatile solutions in vibration/stiffness control of engineering structures, like wearable devices, home appliances, vehicle parts, and civil infrastructures, by providing self-powered sensing and energy generation ability

Flavonoid-rich extracts of Nelumbo nucifera leaves alleviate obesity in HFD-fed mice via microbiota-dependent modulation of brown fat thermogenesis

Ethnopharmacological relevance: Nelumbo nucifera Gaertn (lotus) leaf is a commonly used traditional Chinese herbal medicine with a wide range of pharmacological properties, especially lipid-lowering and weight-loss effects. Accumulating evidence highlights activation of the thermogenic program of brown adipose tissue (BAT) as a promising anti-obesity strategy. However, it remains unclear whether such beneficial metabolic effects induced by the lotus leaf are related to its regulatory role in BAT function. Aim of the study: This work aims to investigate whether the lotus leaf reduces obesity by activating BAT and to elucidate whether the mechanism behind it is related to the regulation of gut microbiota. Material and methods: A mouse model of obesity was established using a high-fat diet (HFD), and the anti-obesity effect of flavonoid-rich lotus leaf extract (LLE) was determined in vivo. An animal energy metabolism monitoring system confirmed that LLE promoted energy expenditure. Then, RT-qPCR, immunohistochemistry, and Western blotting were conducted to detect the expression of genes and proteins involved in BAT thermogenesis. Subsequently, the underlying mechanisms were demonstrated by 16 S rRNA gene sequencing and non-targeted metabolism analysis. Finally, fecal microbiota transplantation (FMT) was performed to investigate the LLE-dependent alleviation of obesity via the gut microbiota-BAT axis. Results: Our study demonstrated that LLE effectively reduced weight gain, ameliorated glucolipid disorders, and enhanced energy expenditure in HFD-fed mice. Notably, LLE augmented BAT activity by increasing thermogenic markers (e.g., SIRT1, PGC-1α, UCP1) and repressing inflammatory responses, potentially through activation of β3-AR/AMPK/p38 signaling pathways. Importantly, LLE could mitigate HFD-induced microbial dysbiosis (decrease in Proteobacteria, Verrucomicbiota, Acidobacteriota, Bacteroides, Dubosiella, and increase in Bilophila, Tyzzerella, Oscillibacter, Akkermansia, and Alistipes) and significantly altered 5 metabolite pathways, especially primary bile acid biosynthesis and linoleic acid metabolism. The FMT experiment confirmed that the microbial changes induced by LLE were associated with reduced body weight, enhanced energy expenditure, increased BAT activity, and thermogenesis. Conclusions: Collectively, our findings reveal that lotus leaf promotes brown fat thermogenesis by modulating gut microbiota, identifying it as a promising new treatment target for obesity

Theoretical investigation of the reaction mechanism for formation of pyridinyl formimidamide ancillary ligand in the synthesis of a new class of iridium(III) complexes

In this study, density functional theory (DFT) calculations were performed to explore the reaction mechanism for the formation of a silver-formimidamide intermediate complex in the synthesis pathway of a novel cyclometallated iridium(III) complex bearing a pyridine-formimidamide ancillary ligand. The purpose of this study is to provide a detailed explanation of how the cyclic carbene ancillary ligand of (2-(4-methylbenzyl)-1H-1,2,4-triazol-1-yl)pyridine, MBpyta converted into acyclic (E)-N-cyano-N-(4-methylbenzyl)-N'-(pyridin-2-yl) formimidamide, CNMBpyfa when undergoing complexation with chloro-bridged iridium(III) dimer [{Ir(F2ppy)2(µ-Cl)}2]. The calculated results showed that the role of silver(I) oxide and the electron-withdrawing effect of the starting ligand in reactants triggered the two stages of deprotonation of two carbons in the starting triazolium salt precursor. Geometrical optimization reveals that the crystal structure of complex Ir(F2ppy)2(CNMBpyfa) has the lowest electronic energy compared to other designated ancillary ligand positions, confirming that the experimental data represent the most stable state of the synthesized complex

A comprehensive review on hybrid lattice meta-structures for biomedical engineering applications

Fabricating lattice structures with optimal physical, mechanical, and biological properties remains one of the key challenges in biomedical engineering. Meta-structures are geometry-driven systems that use structural architecture, often through periodic, hierarchical or graded designs, to achieve mechanical or functional properties not typically found in conventional bulk materials. Lattice meta-structures have emerged as a promising approach to meet the demanding requirements of biomedical devices, particularly due to their ability to mimic the structural and functional characteristics of host tissues. However, conventional meta-structures —composed of repeating single unit cells— often fall short in addressing all critical performance criteria. To overcome these limitations, hybrid meta-structures —combining two or more repeating architectures—have been developed, combining different structural architectures to enhance adaptability and functionality. The present review aims to provide a comprehensive overview of the design strategies and biomedical applications of hybrid meta-structures. Additionally, it offers insights into current challenges and outlines potential directions for future research in this rapidly evolving field