Ciprofloxacin, Drones, and Amino Acids... In Space!

Today I Learned:
1) Ciprofloxacin is one of the stronger, cheaper antibiotics on the market. It's a little unusual in its mechanism of action -- most antibiotics I know of work by either inhibiting synthesis of the bacterial cell wall or by blocking bacterial ribosomes, but ciprofloxacin works by inhibiting several bacterial topoisomerases and gyrases, which are important for DNA replication (they help unwind DNA and relieve torsional stress from the unwinding).

Ciprofloxacin also, rarely, has a couple of nasty side effects. In addition to the usual sort of stuff (nausea, abnormal liver function, muscle weakness, etc), ciprofloxacin is associated with an increased risk of tendon rupture. It apparently weakens several kinds of connective tissue important for holding tendons together. It's a rare side effect, so it's still used pretty commonly, but it's not supposed to be given to anyone with known tendon problems or to the elderly.

Ciprofloxacin may also cause retinal detachment, which is just as nasty as it sounds (evidence of retinal detachment caused by ciprofloxacin: http://ift.tt/1MYk1vR). However, a Danish study tried to replicate the finding and failed: http://ift.tt/217bwt0. The authors claim that they can rule out any more than a 3-fold increase in risk of retinal detachment due to small sample size (they looked at about 500 cases of retinal detachment, out of a total of around 660,000 cases of ciprofloxacin use), which corresponds to "in the worst-case scenario [...] no more than 11 additional cases of retinal detachment per 1,000,000 treatment episodes". So if it does cause retinal detachment, it's *quite* rare.

2) ...a little bit about drone design. For one thing, there are tricopters as well as quadcopters. Also, off-the-shelf drones primarily use PID controllers. Also, control sticks for flying off-the-shelf drones (and probably other remote-control aircraft) typically use something called "expo", which is an exponential mapping between distance-from-the-center-of-the-control-pad-to-the-stick to the size of the effect on the drone. This is so you can make fine adjustments near the center of the stick-range while still allowing large changes with big stick movements.

3) ...a bit about how we know about amino acids* in space. Incidentally, there are amino acids in space, in surprising abundance. We know this from at least two independent sources. Firstly, astronomers in 1994 found spectral lines for the amino acid glycine in three nebulae, and I believe other experiments have found similar spectral data in other gas clouds.

Secondly, we've found complex amino acid mixtures inside fresh meteorites, which includes many amino acids not found on Earth. Moreover, in 2009 NASA's Stardust mission brought home dust samples from the comet Wild 2, which contained detectable amounts of glycine (contamination was ruled out by the glycine's radiological signature -- it had more Carbon 13 than Earth glycine).

*Amino acids == the monomers that make up proteins, which are the complex molecules that perform most biological functions.