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Physics-Based Simulation of Contact-Induced Facial Wrinkling
Item type: Conference Paper
Montes Maestre, Juan Sebastian; Kavan, Ladislav; Boyer, Edmond; et al. (2026)
Facial skin dynamics are inherently challenging to simulate due to a combination of geometric, material, and anatomical complexities. Human skin is a nonlinear layered material with spatially heterogeneous attachments to the underlying tissues. During contact events, localized compression and shear induce mechanical instabilities, leading to fine-scale wrinkling patterns governed by a delicate interplay of geometry, boundary conditions, and through-the-thickness stresses.
We present a finite element framework to simulate contact-induced wrinkling of facial skin. We model skin as a viscoelastic material with time-dependent relaxation that governs the rate, persistence, and damping of wrinkle formation. We employ high-order prismatic solid-shell elements to resolve through-thickness stresses and high-frequency deformation modes. Central to our approach, we introduce a continuum-based formulation of skin ligaments to model heterogeneous skin attachments and provide anatomically inspired mobility constraints. These skin ligaments control the formation and appearance of facial wrinkles by modulating their amplitude, wavelength, and spatial distribution.
We evaluate our method on a set of synthetic examples and compare simulations with real-world footage. These results demonstrate that our skin model produces temporally coherent and visually realistic wrinkle patterns during transient contact.
2026 roadmap on next-generation solid electrolytes for battery applications
Item type: Review Article
Strauss, Florian; Brezesinski, Torsten; Ohno, Saneyuki; et al. (2026)
The global transition to sustainable energy systems requires breakthroughs in electrochemical storage technologies that are not only safe but also resource efficient. Solid-state batteries (SSBs), which use superionic solid electrolytes (SEs) instead of flammable liquid electrolytes, are at the forefront of this transformation. In general, SEs promise increased safety, access to high-voltage cathode and metal anode chemistries, and new avenues for circular design and recyclability. However, to reach their full potential, intertwined challenges related to ion transport, (electro)chemical stability, manufacturing, processing, and cost must be overcome. This 2026 roadmap on next-generation SEs for battery applications outlines new directions that will contribute to research in the field of SSBs over the next decade. It provides an overview of the current state of the art in sulfide- and halide-based SEs for Li and Na systems, examines post-Li/Na chemistries (K, Mg, and others), and highlights advances in hydroborate, fully reduced (irreducible), and compositionally complex (high-entropy) electrolytes, as well as glass-ceramic electrolytes. Beyond material innovation, the paper emphasizes the critical role of redox activity in SEs, scalable processing, high-throughput synthesis, and machine learning, as well as operando analytics and nuclear magnetic resonance spectroscopy to accelerate discoveries and gain a better understanding of structure-property relationships. Finally, the growing importance of recycling and circular design for ensuring sustainability is highlighted. By combining insights from chemistry, materials science, data (computational) science, and manufacturing, this article assumes that future SEs will progressively evolve from passive components to active design elements in high-energy-density electrochemical systems. The integration of multidisciplinary innovations will be crucial to realizing the potential of SSBs in practical technologies that power a decarbonized world.
Clinical evaluation of a sit-to-stand dual-posture mobility device for people with spinal cord injuries
Item type: Journal Article
Shimizu, Yukiyo; Kadone, Hideki; Eguchi, Yosuke; et al. (2026)
Abstract
Wheelchair users face health risks from prolonged sitting and social barriers owing to the vertical gap between their seated position and standing able-bodied individuals. We present Qolo, a novel standing mobility device equipped with passive exoskeletons for intuitive sit-to-stand transitions. Three prototypes were iteratively evaluated with 13 unique participants with spinal cord injury (SCI) from cervical to lumbar levels (C5-L3): Qolo-1 (n = 4), Qolo-2 (n = 12), and Qolo-3 (n = 5), with 3 participants completing all three evaluations. The safety and feasibility of standing transitions were assessed, and no adverse events were reported. Success rates improved from 50% with Qolo-1 to 91.7% with Qolo-2. Participants with complete thoracic injuries who struggled with Qolo-1 succeeded with Qolo-2 using increased spring assistance. Qolo-3 achieved dual sitting and standing mobility using an integrated seating system. Forward trunk lean activates spring assistance, providing intuitive control without electric motors. This iterative development through collaboration among rehabilitation physicians, engineers, and wheelchair end-users enabled application to a broader range of injury levels. The exoskeletal mechanism proved safe and feasible for individuals with complete thoracic SCI (T4-T11) and incomplete cervical or lumbar SCI, addressing the unmet need for accessible standing mobility in daily activities. Trial registration: UMIN Clinical Trials Registry, UMIN000016357. Registered on 28 January 2015.
Thinking big: the case for experimental macroecology
Item type: Other Journal Item
Matias, Miguel G.; Alexander, Jake; Freestone, Amy L.; et al. (2026)
Implementing a Second-Harmonic Generator for a Cold-Atom Experiment
Item type: Student Paper
Škrna, Ondřej (2026)