Aberrant Spices, Chromatic Aberrations, and Aberring Lenses

Today I Learned:

1) Lots of really spicy Indian dishes temper the spiciness with either szeschuan peppers (which produces a tingly sensation by activating the receptors that normally detect vibration) or, less dramatically, cardamom or nutmeg (which contain, among other things, mild local anesthetics). I'd wondered before how Indian food can be super spicy from the first bite, yet remain *exactly* that spicy over the whole meal -- apparently that has something to do with it.

2) A chromatic aberration is a shift or stretch in the position of a beam of light passing through a lens that depends on the color of the light. So maybe red light shifts a little to the left, green shifts a little to the right, and blue shifts way to the right -- that sort of thing. Apparently confocal microscopes are often not calibrated very well against chromatic aberrations, which is why co-localization photos (where you take a picture of two different things using different colors and overlay them) often have an annoying shifted effect.

3) There's a cool trick you can play with a cylindrical lens (which is actually the shape of a cylinder sliced down the center of the circular face) to get super high resolution in the Z axis. It turns out that cylindrical lenses have this cool little aberration where they stretch a beam in one axis (X or Y, I forget which) if you're looking at something slightly above the focal plane, but in the other axis (Y or X, respectively) if you're looking at something *below* the focal plane. Moreover, you can calculate the strength of the stretch from the distance off of the focal plane... and vice versa. So by measuring the stretch of what should by all rights by a circular signal, you can tell where a fluorescent point source is with respect to height. Ok, so the best stuff from today happened to not be DNA stuff. That will unlikely hold true -- expect DNA facts!