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The nonlinear strain response of soft material–based snap-through systems enables amplified and accelerated force output. However, efficiency of snap-through energy release is challenging to improve because of the inherent trade-off between initial curvature and stiffness. Here, spatial programming of stiffness variation in the azobenzene-functionalized liquid-crystalline polymer (Azo-LCP) addresses this limitation and achieves efficient photomechanical jumping. Introduction of stiffness mismatch induced localized curvature, which preserved the initial curvature and simultaneously enhanced photomechanical strain responsivity. By programming for symmetry of stiffness variation, we achieved directional or vertical jumping via strategic placement of the rigid region, with corresponding stress accumulation behaviors corroborated by finite element simulations. Integration of patterned stiffness variation with geometric asymmetry enabled both vertical and horizontal jumping within a single structure, without compromising performance. This dual-mode jumper also demonstrated sequential and consecutive jumps under continuous light exposure. 

Shape changes in electron-beam patterned poly(acrylic acid) can be controlled by the many patterning parameters to create gel-based ribbons with both in-plane and out-of-plane pH-dependent swelling anisotropies. 

Abstract Understanding how evolution shapes genetic networks to create new developmental forms is a central question in biology. Flowering shoot (inflorescence) architecture varies significantly across plant families and is a key target of genetic engineering efforts in many crops^1–4. Asteraceae (sunflower family), comprising 10% of flowering plants, all have capitula, a novel inflorescence that mimics a single flower^5,6. Asteraceae capitula are highly diverse but are thought to have evolved once via unknown mechanisms^7,8. During capitulum development, shoot stem cells undergo prolonged proliferation to accommodate the formation of intersecting spirals of flowers (florets) along the disk-shaped head^9,10. Here we show that capitulum evolution paralleled decreases in CLAVATA3 (CLV3) peptide signaling, a conserved repressor of stem cell proliferation. We trace this to novel amino acid changes in the mature CLV3 peptide which decrease receptor binding and downstream transcriptional outputs. Using genetically tractable Asteraceae models, we show that reversion ofCLV3to a more active form impairs Asteraceae stem cell regulation and capitulum development. Additionally, we trace the evolution ofCLV3and its receptors across the Asterales allowing inferences on capitulum evolution within this lineage. Our findings reveal novel mechanisms driving evolutionary innovation in plant reproduction and suggest new approaches for genetic engineering in crop species. 

Abstract Compliant mechanisms with reconfigurable degrees of freedom are gaining attention in the development of kinesthetic haptic devices, robotic systems, and mechanical metamaterials. However, available devices exhibit limited programmability and form-customizability, restricting their versatility. To address this gap, we propose a metastructure concept featuring reconfigurable motional freedom and tunable stiffness, adaptable to various form factors and applications. These devices incorporate passive flexures and actively stiffness-changing rods to modify kinematic freedom. A rational design pipeline informs the flexures’ topological arrangements, geometric parameters, and control signals based on targeted mobilities, enabling the creation of unitary joints with up to six degrees of freedom. Our demonstrative application examples include a wrist device that has an effective stiffness of 0.370 Nm/deg (unlocked state, 5% displacement) to 2.278 Nm/deg (locked state, 1% displacement) to enable dynamic joint mobility control, a haptic thimble device (2.27-52.815 Nmm⁻¹at 1% displacement) that mimics the sensation of touching physical materials ranging from soft gel to metal surfaces, and a wearable device composed of multiple joints tailored for the arm and hand to augment haptic experiences or facilitate muscle training. We believe the presented method can help democratize compliant metastructures development and expand their versatility for broader contexts.