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BEGIN:VEVENT
DTSTAMP:20260813T032758Z
LAST-MODIFIED:20121116T203436Z
DTSTART:20070126T173000Z
DTEND:20070126T190000Z
UID:event71@bu.edu
URL:http://physics.bu.edu/internal/events/show/71
SUMMARY:Ion transport in biological ion channels and silicon nanopores: No 
	life without entropy
DESCRIPTION:Featuring B.I. Shkolvskii\, University of Minnesota\n\nPart of 
	the Biophysics/Condensed Matter Seminar Series.\n\nJoint Condensed Matter/B
	iophysics Seminar\n\nThis talk deals with ion charge transport via a protei
	n ion channel in a lipid membrane or a water filled nanopore in a silicon f
	ilm. It is known that due to the large ratio of dielectric constants of wat
	er filling the channel and of the surrounding channel walls\, the electric 
	field of an ion placed inside the channel is confined inside the channel\, 
	so that the ion has to cross a large electrostatic self-energy barrier. Two
	 oppositely charged ions can easily enter the channel but they do not condu
	ct because they are connected by interaction potential linearly growing wit
	h the distance between them similarly to two quarks. This should lead to ne
	gligible conductance of the channel. Nevertheless\, ion channels function.\
	n\nI will talk about two mechanisms employed by Nature for elimination of t
	he electrostatic barrier in ion channels\, namely effects of salt ions diss
	olved in water and of immobile charges on the channel internal walls. Both 
	type of charges lead to insulator-metal crossover.  The first transition re
	sembles Mott transition in the exciton gas with increasing density of excit
	ons; the second one resembles Mott transition in a doped semiconductor with
	 growing concentration of impurities. Of course\, I talk about completely c
	lassical phenomenon (happening in water at room temperature)\, where the en
	tropy plays the role of quantum mechanics.\n\nOur transition is also simila
	r to the thermal deconfinement of quarks in heavy nuclei collisions leading
	 to quark–gluon plazma.
LOCATION:SCI 352\, 590 Commonwealth Avenue\, 02215
STATUS:CONFIRMED
CLASS:PUBLIC
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