BEGIN:VCALENDAR VERSION:2.0 PRODID:researchseminars.org CALSCALE:GREGORIAN X-WR-CALNAME:researchseminars.org BEGIN:VEVENT SUMMARY:Tomislav Plesa (University of Cambridge) DTSTART:20221027T150000Z DTEND:20221027T153000Z DTSTAMP:20260421T123923Z UID:MoRN/55 DESCRIPTION:Title: In tegral feedback in synthetic biology: Negative-equilibrium catastrophe \nby Tomislav Plesa (University of Cambridge) as part of Seminar on the Ma thematics of Reaction Networks\n\n\nAbstract\nA central goal of synthetic biology is the design of molecular\ncontrollers that can manipulate the dy namics of intracellular networks\nin a stable and accurate manner. To addr ess the fact that detailed knowledge\nabout intracellular networks is unav ailable\, integral-feedback controllers (IFCs)\n have been put forward for controlling molecular abundances.\nThese controllers can maintain accurac y in spite of the uncertainties in the controlled networks.\nHowever\, thi s desirable feature is achieved only if stability is also maintained.\nIn this talk\, we show that molecular IFCs can suffer from a hazardous instab ility called\nnegative-equilibrium catastrophe (NEC)\, whereby\nall nonneg ative equilibria vanish under the action of the controllers\,\nand some of the molecular abundances blow up.\nWe analyze the performance of a family of bimolecular IFCs \nwhen uncertain unimolecular networks are controlle d\,\nand show that it is possible to safeguard against NECs.\nIn contrast\ , when IFCs are applied on uncertain bimolecular \n(and hence most intrace llular) networks\,\nwe show that preventing NECs generally becomes an intr actable problem\nas the number of interacting molecular species increases. \nNECs therefore place a fundamental limit to\ndesign and control of molec ular networks.\n LOCATION:https://researchseminars.org/talk/MoRN/55/ END:VEVENT END:VCALENDAR