BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//132.216.98.100//NONSGML kigkonsult.se iCalcreator 2.20.4//
BEGIN:VEVENT
UID:20250628T074051EDT-5317ide0HU@132.216.98.100
DTSTAMP:20250628T114051Z
DESCRIPTION:Control of Cell Volume with Space-Charge Layers and Bulk Electr
 oneutrality\n\nCharles S. Peskin\, New York University\n	Tuesday September 
 12\, 12-1pm\n	Zoom Link: https://mcgill.zoom.us/j/86855481591\n	In Person: 5
 50 Sherbrooke\, Room 189\n	\n	Abstract: Animal cells do not have cell walls\
 , and their membranes cannot withstand any significant pressure difference
 . Macromolecules that are confined to the cell contain numerous charged gr
 oups\, and the counterions of these charges have a substantial osmotic eff
 ect\, pulling water into the cell. The cell therefore faces a severe osmot
 ic challenge to avoid having its volume increase until the cell bursts. Th
 is challenge is met by pumping ions\, specifically by continuous action of
  the Na+/K+ exchange mechanism\, which repeatedly expels three Na+ ions fr
 om the cell in exchange for two K+ ions from the external environment. Thi
 s allows the cell to reach an out-of-equilibrium steady state\, which can 
 only be maintained by the constant expenditure of energy. The energy sourc
 e is ATP hydrolysis.\n\nA by-product of the above mechanism is an electric
 al potential difference across the cell membrane. All animal cells have su
 ch a resting potential\, on the order of 70 mV negative inside\, and neuro
 ns (among some other cell types) have learned the trick of transiently mod
 ulating this potential as a signaling mechanism. Thus\, the control of cel
 l volume is the foundation of electrophysiology.\n\nA typical animal cell 
 is therefore charged. The charge is not distributed uniformly over the cel
 l\, but instead is concentrated in a very thin space-charge layer adjacent
  to the inner face of the cell membrane. A similar layer with charge of op
 posite sign is formed adjacent to the outer face. We use the linearized Po
 isson-Boltzmann equation for the description the space-charge layers\, and
  in this way we are able to evaluate their ionic content. This is needed f
 or the formulation of the ODE that describe the control of cell volume\, e
 specially to obtain results in which volume changes interact with electric
 al signaling\, so that the capacitance of the cell membrane cannot be negl
 ected.\n
DTSTART:20230912T160000Z
DTEND:20230912T170000Z
SUMMARY:QLS Seminar Series - Charles S. Peskin
URL:/qls/channels/event/qls-seminar-series-charles-s-p
 eskin-350449
END:VEVENT
END:VCALENDAR