Electric

Mar. 23rd, 2019 10:00 pm
rebeccmeister: (Default)
[personal profile] rebeccmeister
Several of the next couple of labs involve membrane potentials, aka bioelectrics. I was a bit worried about sorting out what I needed from among the existing supplies, but on Friday most serendipitously my predecessor stopped by so I was able to ask her about a few key things in person.

That meant that today I was able to come in, organize a bunch of stuff, get some things set up, do some initial testing, and then go home at a reasonable hour so I could work on another task that's overdue (not done yet; must finish in the morning because my brain's gone soft).

What we'll be doing in this lab: examining characteristics of skeletal muscle isometric twitches (contractions). This involves stimulating the muscle or sciatic nerve in different ways, which means using some form of electrical stimulator. The good news is, as my predecessor pointed out, we have a set of these:



These stimulators are so satisfyingly old-school. Knobs and toggle switches, oh my!

I would like to write more commentary about our main physiology computer interface system*, but I think I have to save that for another day. It's both good and fine, and extremely annoying, all at the same time, because proprietary software reasons. In theory it's possible to accomplish the same goal as with the Grass Stimulator via the interface's software and hardware, but that would require having the right connectors, which the company would happily charge me an arm and a leg for. I could probably develop substitutes, but that takes more time and running around than I have at the moment.

So now, the next big logistical challenge is going to be figuring out the setup for a lab where we'll be studying active transport across frog skin. That involves being able to supply a continuous voltage to voltage clamp the membrane. The company that sells the chamber to hold the skin will also sell me the electrodes for this project, but the electrodes collectively cost a good $600 per chamber, which we can't afford just yet. Plus I don't know how or whether those will interface with our computer interface system. I am also going to get some nice multimeters (microammeters) for that one.

My predecessor also pointed out that way back in the day, they just used chart recorders for all this stuff. We still have at least one, actually, for a bomb calorimeter. I love all the old instrumentation. One of these days I WILL bust out the bomb calorimeter for the students.

I am still waking up at night, with the mental checklist going, because on top of the frog skin lab, I also need to have logistics lined up for studying salt and osmotic balance in crayfish, and for studying excretion in insects (need to order some Amaranth Red), and for studying nutrient regulation in insects. In a lot of ways the more immediate stuff is fun - just get the supplies together and go. It's the timing for the upcoming labs that's still incredibly stressful, because things have to get ordered far enough in advance to ensure that they will actually show up on time. And I don't always know how long that window of opportunity is.

And that's just one part of the job, not to mention other things going on in my life.



* I'm not going to mention the brand, at the moment. Maybe later. I need to learn this landscape a little more first.

Date: 2019-03-24 08:16 am (UTC)
myka: (Default)
From: [personal profile] myka
That stimulator looks beautiful, like my dad's old radios...

Date: 2019-03-24 04:43 pm (UTC)
randomdreams: riding up mini slickrock (Default)
From: [personal profile] randomdreams
What sort of range do the microammeters read? It may be worthwhile doing some sort of DIY on those: a microcontroller sensing the voltage across a current sense resistor, because then it can both display it and send it to a host computer. That way your per-unit would be in the $50 range, which should be half to 1/20 of competing commercial solutions.

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