Electronic noses sniff out volatile organic compounds
May 2023, phys.org
Many e-noses generate different signals toward VOCs of the same concentration when the sensor is located in different parts of the "nose" chamber:"To counteract this problem, the fluidic behavior of the gas flow needs to be well controlled," said author Weiwei Wu. "This ensures a uniform fluidic field and concentration of VOCs in the chamber and avoids generating any fake sensing characteristics."A vertical chamber that looks much like a showerhead promotes vertical flow so gas spreads through holes at the bottom of the device and around to evenly distributed sensors.
via Interdisciplinary Research Center of Smart Sensors, School of Advanced Materials and Nanotechnology, Xidian University; Intelligent Perception Research Institute, Zhejiang Lab, Hangzhou: Controlling fluidic behavior for ultrasensitive volatile sensing, Applied Physics Reviews (2023). DOI: 10.1063/5.0141840
Note: This problem has come up in two other papers where they talk about how the two different nostrils cancel each other out because they can't rely on evenly distributed air; it messes up the statistics, so at least with two different nostrils, you can have some error correction. See "Domestic cat nose functions as a highly efficient coiled parallel gas chromatograph", We et al. PLoS Computational Biology (2023). DOI: 10.1371/journal.pcbi.1011 https://pubmed.ncbi.nlm.nih.gov/37384594/ and "Odor representations from the two nostrils are temporally segregated in human piriform cortex", Dikeçligil et al, Current Biology (2023). DOI: 10.1016/j.cub.2023.10.021 https://dx.doi.org/10.1016/j.cub.2023.10.021
Image credit: AI Art - A Person Getting Their Head Electrocuted as Interpreted by the Internet - 2023
Perceiving the smell of lemon, geranium or eucalyptus: A study on the electrical signals behind human olfaction
Jul 2023, phys.org
Somewhat related to electronic noses, real-live odor receptors obtained from nasal biopsies:
"Until now, nobody had measured in intact human tissue the electrical activity of cells, neurons and epithelial cells that form the olfactory epithelium of our nose in which odorant molecules are captured."
via International School of Advanced Studies, Aldo Moro University of Bari, University of Trieste, and the Otorhinolaryngology Clinic of Azienda Sanitaria Universitaria Giuliano Isontina: Andres Hernandez-Clavijo et al, Shedding light on human olfaction: electrophysiological recordings from sensory neurons in acute slices of olfactory epithelium, iScience (2023). DOI: 10.1016/j.isci.2023.107186
'Electronic tongue' holds promise as possible first step to artificial emotional intelligence
Oct 2023, phys.org
It sounds to me a bit of a stretch right now to call this emotional intelligence; it sounds like basic chemical detection to me, but with the addition of a memristor.
The memristor is the new part, and one day we will have gustatory chips, and olfactory chips, vision chips, etc.; chips for everything; everything will have its own chip. Christmas chips and new mother chips and traffic chips for cars and ambient energy harvesting chips for sneakers and even organic chemistry chips for med students so they don't have to study. Everything will have its own chip. There won't be categories of chips, instead every single thing will have its own chip. Just not today.
Continuing:
The artificial tastebuds comprise tiny, graphene-based electronic sensors called chemitransistors that can detect gas or chemical molecules. The other part of the circuit uses memtransistors, which is a transistor that remembers past signals, made with molybdenum disulfide. This allowed the researchers to design an "electronic gustatory cortex" that connect a physiology-drive "hunger neuron," psychology-driven "appetite neuron" and a "feeding circuit.""When detecting salt the device senses sodium ions. This means the device can 'taste' salt.""We are trying to make arrays of graphene devices to mimic the 10,000 or so taste receptors we have on our tongue."
via Penn State: Subir Ghosh et al, An all 2D bio-inspired gustatory circuit for mimicking physiology and psychology of feeding behavior, Nature Communications (2023). DOI: 10.1038/s41467-023-41046-7
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