Lasers are such a fundamental piece of technology today that we hardly notice them. So cheap that they can be given away as toys and so versatile that they make everything from DVD players to corneal surgery a reality, lasers are one of the building blocks of the modern world. Yet lasers were once the exclusive province of physicists, laboring over expansive and expensive experimental setups that seemed more the stuff of science fiction than workhouse tool of communications and so many other fields. The laser has been wildly successful, and the story of its development is an intriguing tale of observation, perseverance, and the importance of keeping good notes.
When you consider that almost every single cell in your body has more than a meter of DNA coiled up inside its nucleus, it seems like it should be pretty easy to get some to study. But with all the other cellular gunk in a crude preparation, DNA can be quite hard to isolate. That’s where this cheap and easy magnetic DNA separation method comes in. If it can be optimized and tested with some help from the citizen science community.
Commercial DNA separation methods generally involve mixing silica beads into crude cell fractions; the DNA preferentially binds to the silica, making it possible to mechanically separate it from the rest of the cellular junk. But rather than using a centrifuge to isolate the DNA, [Justin] from The Thought Emporium figured that magnets might do a better job. It’s not a new idea — biotech companies offer magnetic separation beads commercially, but at too steep a price for [Justin]’s budget. His hack comes from making magnetite particles from common iron compounds like PCB etchant and moss killer, and household ammonia cleaner. The magnetite particles are then coated with sodium silicate solution, also known as waterglass. The silica coating should allow the beads to bind to DNA, with the magnetic core taking care of separation.
[Justin] was in the process of testing his method when he lost access to the needed instruments, so he’s appealing to the larger science community for help optimizing his technique. Based on his track record of success in fields ranging from satellite tracking to graphene production, we’ll bet he’ll nail this one too.
Fellow Hackaday writer [Ethan Zonca] was doing a little bit of woodworking recently and decided to test ammonia fuming on a small piece of oak. Yes, this means discoloring wood with ammonia vapor, and it’s a real technique. [Ethan] wanted to increase the rate of evaporation of his ammonia solution and decided to make an immersion heater. Out of a vacuum tube.
This is a non-optimal solution to the problem of heating a solution of ammonia – already a bad idea unless you have a fume hood – but it gets better. The vacuum tube was slightly cracked, something easily fixed with a bit of silicone sealant. This was then immersed in an ammonia solution, wired up to a driver board and controlled by a homebrew PID controller. If it’s stupid and it works, it’s not stupid.
After getting the ammonia solution up to 30° C, a noxious cloud of ammonia seeped into a piece of oak. This was left overnight, and the result is something that looks like old barn wood, and looks great after some linseed oil is rubbed into it. This is only a test run for fuming an entire desktop this spring, and while that’s a project that will require a real heater (and doing it outside), it’s still a great demonstration of lateral thinking and great woodworking techniques.
[Blake] just finished a gas sensor suite built from Gadgeteer parts. The three sensors are the cylindrical towers along the left hand side of the assembly. The one at the top (with the orange ring) is an alcohol sensor. The middle one senses ammonia and the lower sensor measures air quality. Also rolled into the mix are temperature and humidity sensors.
You can collect a lot of data with this type of setup. To keep it organized [Blake] used the ThingSpeak interface. Using the NIC in the upper right he uploads the measurements for real-time graphing. The setup is explained in detail in the video after the break, including a test with some cleaning ammonia.
We haven’t tried out the Gadgeteer system for ourselves yet. But you’ve got to admit that the ribbon cable connector system the family of parts uses really helps to keep a rather complicated setup like this one nice and tidy.