scholarly journals A stretchable and adhesive ionic conductor based on polyacrylic acid and deep eutectic solvents

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Gang Li ◽  
Zhihao Deng ◽  
Minkun Cai ◽  
Kaixi Huang ◽  
Mengxue Guo ◽  
...  
Keyword(s):  
Polyacrylic Acid ◽  
Low Temperatures ◽  
Deep Eutectic Solvents ◽  
Ionic Conductor ◽  
High Signal ◽  
Signal Quality ◽  
High Adhesion ◽  
Stretchable Electrode ◽  
Electromyographic Signal ◽  
Surface Electromyographic Signal

AbstractHydrogels are a widely used ionic conductor in on-skin electronic and iontronic devices. However, hydrogels dehydrate in the open air and freeze at low temperatures, limiting their real applications when they are attached on skin or exposed to low temperatures. Polymer-ionic liquid gels can overcome these two obstacles, but synthetic ionic liquids are expensive and toxic. In this work, we present an ionic conductor based on polyacrylic acid (PAAc) and deep eutectic solvents (DESs) that well addresses the aforementioned challenges. We polymerize acrylic acid in DESs to get the PAAc–DES gel, which exhibits excellent stretchability (> 1000%), high electrical conductivity (1.26 mS cm−1), high adhesion to the skin (~ 100 N m−1), as well as good anti-drying and anti-freezing properties. We also demonstrate that the PAAc-DES gel can be used as an on-skin electrode to record the surface electromyographic signal with high signal quality, or as a transparent stretchable electrode in iontronic devices that can work at –20 °C. We believe that the PAAc–DES gels are an ideal candidate as epidermal electrodes or transparent stretchable electrodes.

scholarly journals Implantable computer-controlled adaptive multielectrode positioning system

2018 ◽  
Vol 119 (4) ◽  
pp. 1471-1484 ◽  
Author(s):  
E. Ferrea ◽  
L. Suriya-Arunroj ◽  
D. Hoehl ◽  
U. Thomas ◽  
A. Gail
Keyword(s):  
Cerebral Cortex ◽  
Large Scale ◽  
Nonhuman Primates ◽  
Tissue Response ◽  
High Signal ◽  
Signal Quality ◽  
Positioning System ◽  
Multielectrode Arrays ◽  
User Friendliness ◽  
Computer Controlled

Acute neuronal recordings performed with metal microelectrodes in nonhuman primates allow investigating the neural substrate of complex cognitive behaviors. Yet the daily reinsertion and positioning of the electrodes prevents recording from many neurons simultaneously, limiting the suitability of these types of recordings for brain-computer interface applications or for large-scale population statistical methods on a trial-by-trial basis. In contrast, chronically implanted multielectrode arrays offer the opportunity to record from many neurons simultaneously, but immovable electrodes prevent optimization of the signal during and after implantation and cause the tissue response to progressively impair the transduced signal quality, thereby limiting the number of different neurons that can be recorded over the lifetime of the implant. Semichronically implanted matrices of electrodes, instead, allow individually movable electrodes in depth and achieve higher channel count compared with acute methods, hence partially overcoming these limitations. Existing semichronic systems with higher channel count lack computerized control of electrode movements, leading to limited user-friendliness and uncertainty in depth positioning. Here we demonstrate a chronically implantable adaptive multielectrode positioning system with detachable drive for computerized depth adjustment of individual electrodes over several millimeters. This semichronic 16-channel system is designed to optimize the simultaneous yield of units in an extended period following implantation since the electrodes can be independently depth adjusted with minimal effort and their signal quality continuously assessed. Importantly, the electrode array is designed to remain within a chronic recording chamber for a prolonged time or can be used for acute recordings with high signal-to-noise ratio in the cerebral cortex of nonhuman primates. NEW & NOTEWORTHY We present a 16-channel motorized, semichronic multielectrode array with individually depth-adjustable electrodes to record in the cerebral cortex of nonhuman primates. Compared with fixed-geometry arrays, this system allows repeated reestablishing of single neuron isolation. Compared with manually adjustable arrays it benefits from computer-controlled positioning. Compared with motorized semichronic systems it allows higher channel counts due to a robotic single actuator approach. Overall the system is designed to optimize the simultaneous yield of units over the course of implantation.

scholarly journals Investigation of Base-free Copper-Catalysed Azide–Alkyne Click Cycloadditions (CuAAc) in Natural Deep Eutectic Solvents as Green and Catalytic Reaction Media

2021 ◽  
Author(s):  
Salvatore V. Giofrè ◽  
Matteo Tiecco ◽  
Angelo Ferlazzo ◽  
Roberto Romeo ◽  
Gianluca Ciancaleoni ◽  
...  
Keyword(s):  
Low Temperatures ◽  
Materials Science ◽  
Cycloaddition Reaction ◽  
Deep Eutectic Solvents ◽  
Green Solvents ◽  
Experimental Conditions ◽  
Active Reaction ◽  
Natural Deep Eutectic Solvents ◽  
Catalytic Intermediates ◽  
Reaction Media

<p>The click cycloaddition reaction of azides and alkynes affording 1,2,3-triazoles is a widely used and effective chemical transformation, applied to obtain relevant products in medicine, biology and materials science. In this work, a set of Natural Deep Eutectic Solvents (NADESs) as green and “active” reaction media, has been investigated in the copper-catalysed azide–alkyne cycloaddition reactions (CuAAc). The use of these innovative solvents has shown to improve the reaction effectiveness, giving excellent yields. NADESs proved to be “active” in these transformations for the absence of added bases in all the performed reactions and in several cases, for their reducing capabilities. The reactions outcomes were rationalized by DFT calculations which demonstrated the involvement of H-bonds between DESs and alkynes as well as a stabilization of copper catalytic intermediates. The green experimental conditions, namely the absence of a base, the low temperatures, the lowering of reagents and the possibility of recycling of the green solvents, outline the great potential of NADESs for CuAAc and in general, for green organic synthesis. </p>

Comparison of SEMG Derived Parameters and Blood Oxygen Saturation in Monitoring Neuromuscular Fatigue in Humans

2013 ◽  
Vol 1 (4) ◽  
pp. 9-19
Author(s):  
M. Tarata ◽  
W. Wolf ◽  
D. Georgescu ◽  
D. Alexandru ◽  
M. Serbanescu
Keyword(s):  
Oxygen Saturation ◽  
Work Performance ◽  
Muscle Activation ◽  
Neuromuscular Fatigue ◽  
Blood Oxygen ◽  
Blood Oxygen Saturation ◽  
Noninvasive Methods ◽  
Electromyographic Signal ◽  
Surface Electromyographic Signal ◽  
Original Approach

The effects of neuromuscular fatigue are various and with serious consequences on work performance and safety. This paper provides a practical overview of several noninvasive methods of investigating neuromuscular fatigue (NMF), mainly via the surface electromyographic signal (SEMG), as essentially related to the muscle contraction and intimately mirroring muscle activation and contraction mechanisms. The purpose of this paper is to identify the most suitable non-invasively derived parameters for detecting and quantifying NMF, to be practically used in monitoring people exposed to high risks, such as fighter pilots. Wavelet Transform-based techniques (WT), as well as another original approach, together with the blood oxygen saturation are analyzed and discussed, based on results from preliminary experiments.

Normalization Patterns of the Surface Electromyographic Signal in the Phonation Evaluation

2015 ◽  
Vol 29 (1) ◽  
pp. 129.e1-129.e8 ◽  
Author(s):  
Patricia Maria Mendes Balata ◽  
Hilton Justino da Silva ◽  
Leandro de Araújo Pernambuco ◽  
Jabson Herber Profiro de Oliveira ◽  
Sílvia Regina Arruda de Moraes
Keyword(s):  
Electromyographic Signal ◽  
Surface Electromyographic Signal
Sign in / Sign up

Export Citation Format

Share Document