Closing in on the Neural Mechanisms of Finger Joint Angle Sense. Focus on “Quantitative Analysis of Dynamic Strain Sensitivity in Human Skin Mechanoreceptors”

Microneurographical recordings from 24 slowly adapting (SA) and 16 fast adapting (FA) cutaneous mechanoreceptor afferents were obtained in the human radial nerve. Most of the afferents innervated the hairy skin on the back of the hand. The afferents' receptive fields were subjected to controlled strains in a ramp-and-hold fashion with strain velocities from 1 to 64% · s−1, i.e., strain velocities within most of the physiological range. For all unit types, the mean variation in response onset approached 1 ms for strain velocities >8% · s−1. Except at the highest strain velocities, the first spike in a typical SAIII unit was evoked at strains <0.5% and a typical SAII unit began to discharge at <1% skin strain. Skin strain velocity had a profound effect on the discharge rates of all classes of afferents. The “typical” peak discharge rate at the highest strain velocity studied was 50–95 imp/s−1 depending on unit type. Excellent fits were obtained for both SA and FA units when their responses to ramp stretches were modeled by simple power functions ( r2 > 0.9 for 95% of the units). SAIII units grouped with SAII with respect to onset latency and onset variation but with SAI units with respect to dynamic strain sensitivity. Because both SA and FA skin afferents respond strongly, quickly, and accurately to skin strain changes, they all seem to be able to provide useful information about movement-related skin strain changes and therefore contribute to proprioception and kinesthesia.

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Quantitative analysis of proinflammatory cytokines (IL-1β, IL-6, TNF-α) in human skin wounds

Forensic Science International ◽

10.1016/s0379-0738(00)00218-8 ◽

2000 ◽

Vol 113 (1-3) ◽

pp. 251-264 ◽

Cited By ~ 99

Author(s):

W Grellner ◽

T Georg ◽

J Wilske

Keyword(s):

Quantitative Analysis ◽

Human Skin ◽

Proinflammatory Cytokines ◽

Skin Wounds ◽

Tnf Α

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An Experimental Study on Static and Dynamic Strain Sensitivity of Smart Concrete Sensors Doped with Carbon Nanotubes for SHM of Large Structures

10.20944/preprints201802.0063.v1 ◽

2018 ◽

Author(s):

Andrea Meoni ◽

Antonella D'Alessandro ◽

Austin Downey ◽

Enrique García-Macías ◽

Marco Rallini ◽

...

Keyword(s):

Carbon Nanotubes ◽

Reinforced Concrete ◽

Experimental Testing ◽

Dynamic Strain ◽

Cement Matrix ◽

Strain Sensitivity ◽

Strain Sensing ◽

Multi Walled Carbon Nanotubes ◽

Material Fabrication ◽

Smart Concrete

The availability of new self-sensing cement-based strain sensors allows the development of dense sensor networks for Structural Health Monitoring (SHM) of reinforced concrete structures. These sensors are fabricated by doping cement-matrix materials with conductive fillers, such as Multi Walled Carbon Nanotubes (MWCNTs), and can be embedded into structural elements made of reinforced concrete prior to casting. The strain sensing principle is based on the multifunctional composites outputting a measurable change in their electrical properties when subjected to a deformation. Previous work by the authors was devoted to material fabrication, modeling and applications in SHM. In this paper, we investigate the behavior of several sensors fabricated with and without aggregates and with different MWCNTs content. The strain sensitivity of the sensors, in terms of fractional change in electrical resistivity for unit strain, as well as their linearity are investigated through experimental testing under both static and dynamically varying compressive loadings. Moreover, the responses of the sensors when subjected to destructive compressive tests are evaluated. Overall, the presented results contribute to improving the scientific knowledge on the behavior of smart concrete sensors and to furthering their understanding for SHM applications.

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