Tuesday, March 28, 2006

Finally, an environmentally responsible nuclear bomb

"US researchers say they have developed 'green' chemicals that could replace the lead-based primary explosives that are used to detonate everything from blasting caps to ballistic missiles."

What will they think of next?

Saturday, March 18, 2006

Biological electric fields

Many living cells keep their interior at a different voltage than their exterior.  The upper limit for human cells seems to be about 50 millivolts.  Normally we think of that as a puny voltage—a flashlight battery is 30 times higher.

But I got to thinking.  Sure, the voltage is smallish, but cell membranes are super thin, in the range of 5 nanometers.  If we divide the voltage by the distance it acts over, we get the electric field strength:

        50 mV / 5 nm = 10 000 000 V/m

Good grief, that is big!  (The dielectric breakdown strength of air is a couple of MV/m.)  So cell polarization is not a subtle force that gently touches trans-membrane proteins.  It is definitely more of a fold-spindle-mutilate interaction.  I am impressed that ion transporters can pump against a potential gradient that large.

Wednesday, March 08, 2006

Microwaved marshmallow Peeps

Food. Of the. Gods.

(Granted, unhealthy, brightly-dyed Gods, but holy nonetheless.)

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