Shape memory alloys (SMAs) are widely utilized as an actuation source in microscale devices, since they have a simple actuation mechanism and high-power density. However, they have limitations in terms of strain range and actuation speed. High-speed microscale SMA actuators are developed having diamond-shaped frame structures with a diameter of 25 µm. These structures allow for a large elongation range compared with bulk SMA materials, with the aid of spring-like behavior under tensile deformation. These actuators are validated in terms of their applicability as an artificial muscle in microscale by investigating their behavior under mechanical deformation and changes in thermal conditions. The shape memory effect is triggered by delivering thermal energy with a laser. The fast heating and cooling phenomenon caused by the scale effect allows high-speed actuation up to 1600 Hz. It is expected that the proposed actuators will contribute to the development of soft robots and biomedical devices.
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http://dx.doi.org/10.1002/smll.201801023 | DOI Listing |
LiNbO domain structures have been widely applied in nonlinear beam shaping, quantum light generation, and nonvolatile ferroelectric memory. The recent developments in nanoscale domain engineering techniques make it possible to fabricate sub-diffracted nanodomains in LiNbO crystal for high-speed modulation and high-capacity storage. However, it still lacks a feasible and efficient way to characterize these nanoscale domains.
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January 2025
Monell Chemical Senses Center, Philadelphia, PA, USA.
The hippocampus (HPC) has emerged as a critical player in the control of food intake, beyond its well-known role in memory. While previous studies have primarily associated the HPC with food intake inhibition, recent research suggests a role in appetitive processes. Here we identified spatially distinct neuronal populations within the dorsal HPC (dHPC) that respond to either fats or sugars, potent natural reinforcers that contribute to obesity development.
View Article and Find Full Text PDFElife
January 2025
Department of Neurology, University of Iowa, Iowa City, United States.
The role of striatal pathways in cognitive processing is unclear. We studied dorsomedial striatal cognitive processing during interval timing, an elementary cognitive task that requires mice to estimate intervals of several seconds and involves working memory for temporal rules as well as attention to the passage of time. We harnessed optogenetic tagging to record from striatal D2-dopamine receptor-expressing medium spiny neurons (D2-MSNs) in the indirect pathway and from D1-dopamine receptor-expressing MSNs (D1-MSNs) in the direct pathway.
View Article and Find Full Text PDFJ Mater Chem B
January 2025
Department of Textile and Fibre Engineering, Indian Institute of Technology Delhi, Hauz Khas, New Delhi-110016, India.
In recent years, the development of biodegradable, cell-adhesive polymeric implants and minimally invasive surgery has significantly advanced healthcare. These materials exhibit multifunctional properties like self-healing, shape-memory, and cell adhesion, which can be achieved through novel chemical approaches. Engineering of such materials and their scalability using a classical polymer network without complex chemical synthesis and modification has been a great challenge, which potentially can be resolved using biobased dynamic covalent chemistry (DCC).
View Article and Find Full Text PDFJ Phys Chem B
January 2025
Single Molecule Analysis Group, Department of Chemistry, The University of Michigan, Ann Arbor, Michigan 48109, United States.
Single-molecule fluorescence resonance energy transfer (smFRET) has emerged as a pivotal technique for probing biomolecular dynamics over time at nanometer scales. Quantitative analyses of smFRET time traces remain challenging due to confounding factors such as low signal-to-noise ratios, photophysical effects such as bleaching and blinking, and the complexity of modeling the underlying biomolecular states and kinetics. The dynamic distance information shaping the smFRET trace powerfully uncovers even transient conformational changes in single biomolecules both at or far from equilibrium, relying on trace idealization to identify specific interconverting states.
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