"Eggs physically repulse me and I'm unable to enjoy beer or wine as they have a flavour I simply call Covid."-Parosmia: 'Since I had Covid, food makes me want to vomit'BBC News, Feb 2021
Thursday, February 4, 2021
Saturday, January 9, 2021
AKA Regeneration of Olfactory Neurons and Combinatorial Perception in People Recovering from the Novel Coronavirus of 2019
The general profile of excitatory vs. inhibitory responses by mitral cells changed with learning and task demands. In naive animals, most responsive cells (71%) responded by excitation to the odours. Following the learning of the 5-decision boundary task, the ratio of excitatory/inhibitory responses reversed. After learning, the majority (71.4%) of neurons now responded by inhibitory calcium transients to the odours (Fig. 6C,E). The ratio of inhibitory vs. excitatory responses reverted back to normal after retraining the mice on the 1-decision boundary task. Specifically, 73.3% of responsive neurons were again excitatory on day 18.
Tuesday, October 20, 2020
|People used to eat mummies.|
Last week for the first time, I saw someone else writing about this, but in the spirit of the season, which is Halloween here in the US. Good time for a perennial favorite here at Limbic Signal:
Thursday, October 15, 2020
For two years straight, Michael Snyder, MD, professor and chair of genetics at Stanford, sported a peculiar accessory — a little gray box strapped to his bicep taking sips of air and recording his exposome cloud.It turns out, at any given time, we are bombarded by a combination of microbes, fungi, chemicals, viruses, particulates and even tiny microscopic animals, a new paper in Cell reported. This whirling plume of particulates is called the human exposome.The long-term goal, Snyder said, is to simplify the device into something that resembles an exposome-monitoring smart watch that can suck up and analyze the atmosphere on its own.
Thursday, October 8, 2020
Tuesday, September 15, 2020
MIT researchers have a new and better way to compress models.It's so simple that they unveiled it in a tweet last month: Train the model, prune its weakest connections, retrain the model at its fast, early training rate, and repeat, until the model is as tiny as you want.
"We study spiking neural networks, which are systems that learn much as living brains do," said Los Alamos National Laboratory computer scientist Yijing Watkins. "We were fascinated by the prospect of training a neuromorphic processor in a manner analogous to how humans and other biological systems learn from their environment during childhood development."Watkins and her research team found that the network simulations became unstable after continuous periods of unsupervised learning. When they exposed the networks to states that are analogous to the waves that living brains experience during sleep, stability was restored. "It was as though we were giving the neural networks the equivalent of a good night's rest," said Watkins.
Thursday, September 3, 2020
Global pandemics are real good for motivating exposure scientists to identify threats in the environment. Add to that the threat detection capabilities of chemosensation (smelling), and you've got some ingredients for a burgeoning field of study that overlaps with olfaction-inspired technologies.
Olfaction is for threat detection perhaps above all things, so it is fitting that we see this application become more common. One common use already being implemented by the company Aclima is the distributed air-quality sensor network for pollutants:
May 2020, phys.org
The IGZO thin-film transistor acts as both an electronic component of the device and also as the NO2-sensing layer. The strongly electron-accepting NO2 molecule is drawn to the electrons on the transistor's surface. The more NO2 molecules that adhere to the IGZO, the more electrons are depleted from its surface, altering its electronic output and triggering an NO2 detection alert.
After a detection event, the sensor is reset by reviving the IGZO layer with the light from an integrated blue LED. Similar to a solar cell, the light generates negatively charged electrons and positively charged holes in the IGZO, which neutralizes the adsorbed NO2 and releases it from the surface. "This is the first study to achieve sensing and revival of a semiconducting metal oxide-based thin-film transistor sensor at room temperature," says Surya.
*Nitrous oxides (NO2) are a by-product of burning fuel, just like carbon monoxide, carbon dioxide, and sulfur oxides, and all of these are harmful to human health.
And here's another related report:
June 2020, phys.org
Researchers in the USA have developed a graphene-based electrochemical sensor capable of detecting histamines (allergens) and toxins in food much faster than standard laboratory tests.
The team created high-resolution interdigitated electrodes (IDEs) on flexible substrates, which they converted into histamine sensors by covalently linking monoclonal antibodies to oxygen moieties created on the graphene surface by a CO2 thermal annealing process.
As an additive manufacturing method that only deposits material where it is needed and therefore minimizes waste, aerosol-jet-printed sensors are low-cost, straightforward to make, and portable. This could potentially enable their use in places where continuous on-site monitoring of food samples is needed to determine and maintain the quality of products, as well as other applications.
-Aerosol-jet-printed graphene electrochemical histamine sensors for food safety monitoring, 2-D Materials, DOI: 10.1088/2053-1583/ab8919
And still further sensorific developments:
June 2020, phys.org
Using a process known as capillary action, akin to water transport in plants, the device uses evaporation to wick fluid that mimics the features of human sweat to a sensor for up to 10 days or longer.
"We expected that the flow of the model sweat will be suppressed by the deposition of a salt layer inside the drying pad," Velev said. "By following the flow of model sweat, we found, quite surprisingly, that such a simple paper construct can achieve continuous sweat pumping and disposal for very long periods."
"The biological markers or drug metabolites that seep in the patient's sweat over a long period will be captured on the paper pad and preserved in a time-stamped manner to be analyzed later, similar to tree rings preserving the record of tree development," Dickey said.
-Principles of long-term fluids handling in paper-based wearables with capillary-evaporative transport, Biomicrofluidics (2020). aip.scitation.org/doi/10.1063/5.0010417
May 2020, phys.org
From this press article: The exposome is the sum of all the environmental drivers of health and diseases: a combination of external factors such as chemicals contained in the air, water or food, and of internal components produced by our organism in response to various stress factors.
Aclima delivers hyperlocal air pollution and climate emissions intelligence at unprecedented block-by-block resolution.