Multiplexing metabolic signals causes significant data distortion. This post explains how, and gives you access to an amazing, interactive tool for exploring the metabolic data distortions produced by this practically universally-used technique! To save cost, almost all metabolic phenotyping systems multiplex their gas analyzers, so that the air streams from the metabolic chambers are analyzed in succession. [...]
A funny thing happened on my way to helping a colleague make sense of the specifications of a metabolic phenotyping system. There were many strange things to mull over. Not the least of these were oxygen and carbon dioxide analyzer accuracy specifications that appeared to be the product of smoke, mirrors, and absinthe-infused coca tea [...]
OK, imagine a mouse in a cage. With Promethion, you can monitor that mouse's position to within a calculated centroid of 2.5 mm (several times higher resolution than legacy systems). You do this with an infrared light array. So, what do you do with those data? Well, you can of course calculate the time which the mouse [...]
Let's say you need to measure the food uptake of an experimental animal, which of course could mean any creature, including you. For the sake of simplicity, imagine a mouse or a rat feeding intermittently from a food hopper. You'd think that all you needed to do was weigh the hopper periodically, such as [...]
This shows a day's worth of data from a single mouse in graphic form, recorded by a Promethion-C system for a research study on which I'm collaborating. The time resolution of the data set is one second. Loads of additional data (such as XY position and so on) didn't make it into the graph but are [...]
When mice (or rats) are wandering around their Promethion system cages and simply being mice (or rats), they interact with the various sensors in their cages – the mass sensors attached to their food and water dispensers, their body mass sensor, their running wheel, and their X-Y open-field position sensor, for example. In the [...]
The essence of metabolic phenotyping is accurate metabolic measurement. As a matter of convenience, cost and feasibility, practically all metabolic phenotyping systems operate in a multiplexed mode, in which a single gas analysis chain is shared between multiple animals, typically 8, 10, 16 or more. Cycle times between metabolic measurements for a given animal vary [...]
I've written quite a lot of scientific data acquisition and analysis software, some of which - like Datacan and ExpeData - are in use in many laboratories around the world. I'm often asked: Why don't you write software for Apple computers rather than PCs? There's a reason, or maybe a couple of them, and here [...]