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Development of laser speckle blood flowmeter for evaluating the physiological function of skin
摘要： Objective: We developed and demonstrated laser speckle ?owgraphy (LSFG) for two-dimensional (2D) skin blood ?ow (SBF) measurements to facilitate the noninvasive comparisons of SBF between individuals. Approach: By using morphing technology with a face mesh to compare SBF spatial distributions among individuals, we examined the practicability of SBF measurement with LSFG. Main results: (1) The uniformity of SBF measurement was demonstrated by examinations at different distances and angles for healthy subjects. (2) Mean blur rate (MBR)—a blood ?ow index of LSFG—exhibited signi?cant correlation with the thermal diffusion method (TDM)—an established blood ?ow measurement method—suggesting that MBR is an effective index of SBF. (3) Blowout time, the half-width duration/duration of one cardiac cycle, exhibited signi?cant negative correlation with age and positive correlation with stratum corneum hydration. Signi?cance: These results suggest that LSFG is useful for evaluating SBF-related skin properties, and it has signi?cant potential in medicine and cosmetology.
关键词： aging,stratum corneum hydration,skin blood ?ow,laser speckle ?owgraphy,morphing,strain-gauge plethysmography,thermal diffusion
更新于2025-09-23 15:19:57
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Dewetted nanostructures of gold, silver, copper, and palladium with enhanced faceting
摘要： At the foundation of nanoscience and nanotechnology is the ability to shape-engineer nanometric objects so as to exert control over their physical and chemical properties. Architectural control is achieved by manipulating thermodynamic and kinetic factors that are able to guide reactions along pathways that lead to the formation or elimination of particular crystal facets. While the dewetting of ultrathin metal films provides a straightforward method for generating substrate-based metallic nanostructures, the ability to shape-engineer these structures is limited to such an extent that even the formation of highly faceted equiaxed structures often proves challenging. This, however, is not the case for colloidal syntheses where the exquisite chemical controls and synthetic ease offered by liquid-phase chemistry has led to the generation of a diverse library of nanostructure architectures. Here, it is demonstrated that the faceting of dewetted structures of gold, silver, copper, and palladium can be enhanced by subjecting them to a liquid-phase chemical environment in which metal ions are reduced to a neutral state and deposited on the nanostructure surface in manner that leads to facet formation. The faceting procedure, which can be carried out in minutes, is also shown to be amenable to a templated dewetting approach in which lithographically-defined metal discs formed in an array each agglomerate to form a single nanostructure. The work has the potential to increase the functionality of dewetted nanostructures by enabling facet-dependent chemical reactivity and plasmonic hot spots.
关键词： tetrahexahedron,chemical synthesis,facets,thermal diffusion,epitaxial growth
更新于2025-09-09 09:28:46