iiinova — where your digital self keeps evolving

Markus Deserno @markusdeserno.bsky.social · 16/10/2026

I’m not a finance wizard, so I might misunderstand what “pops” means.

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Markus Deserno @markusdeserno.bsky.social · 13/10/2026

Dumbo has been staring at me for two hours straight. 😅

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Markus Deserno @markusdeserno.bsky.social · 03/10/2026

New achievement unlocked 😳 This was about to happen this year, but it still feels unreal to actually see it. If even a small fraction of these citations came from people whose work benefitted from our discussion of such super technical details, then I am proud and happy!

I cracked the "1000 citations bar" on Google Scholar for this paper:

https://scholar.google.com/citations?view_op=view_citation&hl=en&user=1J28ExgAAAAJ&citation_for_view=1J28ExgAAAAJ:u5HHmVD_uO8C

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Markus Deserno @markusdeserno.bsky.social · 25/09/2026

PANTHEON What an absolute masterpiece. Just truly blown away.

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Markus Deserno @markusdeserno.bsky.social · 17/09/2026

I think if Hegseth knew who Leni Riefenstahl was, he’d be sad that she is dead.

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Markus Deserno @markusdeserno.bsky.social · 08/09/2026

Hi, #notability app! I am *that* close to ditching you forever. Your absolutely coercive business approaches are repugnant. I don't *want* to grant you permission to record, but you will not let me proceed. You put "upgrade to PRO" screens into my workspace that I cannot remove! F you.

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Markus Deserno @markusdeserno.bsky.social · 31/08/2026

📣 I am super thrilled to announce that during “Emerging Science Week” the MSAF subgroup of the Biophysical Society will run a webinar with three awesome speakers on “Lipids Feeling the World.” More info, including how you sign up, is contained in the ALT text of the image! Please share widely! 🧪

Lipids form the compartments that organize life. While doing so, they interact with an incredible variety of other molecules and supramolecular structures—things that touch the membrane on either side, are embedded inside, or simply want to get through. What are the chemical and biophysical principles that shape such interactions? How have biomembranes evolved to become such versatile interfaces to the world? In this webinar we will hear from three scientists who have examined questions of this kind from different directions, focusing on different molecules, and using different tools.

Speakers:

(1) Janice Robertson, Dept. of Biochemistry and Molecular Biophysics, Washington University St. Louis, USA
(2) Luca Monticelli, Molecular Microbiology and Structural Biochemistry, INSERM, Lyon, France
(3) Rumiana Dimova, Biophysics Lab, Max-Planck-Institute for Colloids and Interfaces, Potsdam, Germany

Here’s the link to register:

https://my.biophysics.org/Events/Calendar-Of-Events/Meeting-Home-Page?meetingid=4ea7bbbf-b695-f111-8075-6045bdff16f4

Attention: you’ll be asked to sign in or create an account. That’s just to keep track and send you an access link. YOU WILL NOT HAVE TO BE OR BECOME A BPS MEMBER!

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Markus Deserno @markusdeserno.bsky.social · 09/08/2026

Textbook case of not understanding the first amendment.

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Markus Deserno @markusdeserno.bsky.social · 06/08/2026

We have a great statue of him in Pittsburgh, right at the baseball stadium. And that bridge in the background—it’s the Roberto Clemente Bridge!

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Markus Deserno @markusdeserno.bsky.social · 16/07/2026

Hot Metal Bridge, crossing the Monongahela river on a dedicated pedestrian/bike path, Pittsburgh.

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Markus Deserno @markusdeserno.bsky.social · 12/07/2026

This bird just briefly visited me on my window sill. Is this a baby cardinal?

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Markus Deserno @markusdeserno.bsky.social · 05/07/2026

🎇 Happy anniversary, America! May there be happy years in your future! 🎆

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Markus Deserno @markusdeserno.bsky.social · 03/07/2026

Thanks for the alt text. Current image reliability on Bluesky leaves a lot to be desired…

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Markus Deserno @markusdeserno.bsky.social · 23/06/2026

That’s awkward—but only for a short while! Once the average nonlinear solution has relaxed, the time dependence in the coefficients vanishes and we go back to an exactly solvable Ornstein-Uhlenbeck process. And, importantly: the elastic coupling remains in the equation! 23/26

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Markus Deserno @markusdeserno.bsky.social · 23/06/2026

Our paper walks you through the tricky but beautiful derivation of what is called a “system size expansion”, or “linear noise approximation.” The upshot is, we get a much simpler PDE, which is close to an Ornstein-Uhlenbeck process—except its coefficients are time dependent! 22/26

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Markus Deserno @markusdeserno.bsky.social · 23/06/2026

For those interested in funky animations—here’s an illustration of the time evolution of P(N+,t) for the case N=100, with an initial N+ of 10. Observe that the variance converges faster than the mean, so that the asymptotic motion of the probability density is a “sideways slide.” 20/26

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Markus Deserno @markusdeserno.bsky.social · 23/06/2026

Note that for the “ideal gas case” (i.e., constant rate r0) this Fokker-Planck equation HUGELY simplifies, and we get a very elegant analytical solution: a Gaussian with a time-dependent mean and variance! This is called an “Ornstein-Uhlenbeck process”: diffusion in a quadratic potential! 19/26

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Markus Deserno @markusdeserno.bsky.social · 23/06/2026

This equation is easy to write down, but generally hard to solve—especially analytically. But if we’re OK with a CONTINUUM APPROXIMATION, we can (via the so-called “Kramers-Moyal expansion”) derive a partial differential equation (PDE) for P(N+,t): the FOKKER-PLANCK EQUATION. 17/26

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Markus Deserno @markusdeserno.bsky.social · 23/06/2026

In our paper we derive, via a sequence of standard arguments, “equations of motion” for the probability distribution P(N+,t) of having N+ lipids in the upper leaflet at time t. The most intuitive one is the “master equation,” shown and briefly motivated in the attached image. 16/26

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Markus Deserno @markusdeserno.bsky.social · 23/06/2026

Example: here are two stochastic trajectories (created by the so-called “Gillespie algorithm”), and a “red haze” of 500 more. Obviously, the (blue) solution to our beloved rate equation only describes the AVERAGE time evolution. Question: what can we say about the FLUCTUATIONS around it? 15/26

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Markus Deserno @markusdeserno.bsky.social · 23/06/2026

Now that lipids see each other, let’s have different types! Say, 300 A-lipids and 200 B-lipids, with the A’s initially balanced, but not the B’s. We get a rapid relaxation of ABUNDANCE (which messes up the original A-balance) and a much slower relaxation of COMPOSITION (which restores it). 10/26

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Markus Deserno @markusdeserno.bsky.social · 23/06/2026

Example time: 300 lipids, initially 175 in the upper leaflet. (That’s a hefty 17% initial relative abundance asymmetry.) The ideal and stress-corrected decay to the equilibrium 150 lipids per leaflet is shown here (for α=19). Observe the massively faster decay driven by elastic stresses! 9/26

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Markus Deserno @markusdeserno.bsky.social · 23/06/2026

Two things are notable. First, for typical systems α=19, so this parameter is NOT small! Second, if the rates are state-dependent, our good old flip-flop rate equation becomes nonlinear! 😬 8/26

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Markus Deserno @markusdeserno.bsky.social · 23/06/2026

In our paper we explain that the ratio between this parameter and the thermal energy yields a new dimensionless “elastic coupling parameter,” α, which determines how the abundance asymmetry affects flip-flop rates. Namely: exponentially! 7/26

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Markus Deserno @markusdeserno.bsky.social · 23/06/2026

If for whatever reason the two leaflets are unevenly packed, each one experiences an elastic energy that quadratically penalizes the difference between the actual and the optimal area. The key parameter is the product of area expansion modulus and area per lipid. 6/26

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Markus Deserno @markusdeserno.bsky.social · 23/06/2026

We can define a relative abundance asymmetry as the normalized number difference between the upper and lower leaflet. It follows a simple differential equation that describes the exponential relaxation from some initial asymmetry to the equilibrium steady state. 4/26

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Markus Deserno @markusdeserno.bsky.social · 23/06/2026

The canonical approach uses linear first-order rate equations. If N+ and N– = N – N+ are the lipid numbers in the upper (+) and lower (–) leaflet, then each leaflet loses lipids proportional to its current number, times some rate. And it gains what the other one loses. 3/26

Free celtic frame decoration for this and several subsequent images comes from this webpage:
https://freesvg.org/celtic-frame-in-black-and-white-vector-drawing

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Markus Deserno @markusdeserno.bsky.social · 23/06/2026

First off—what is this about? We know that lipids can “flip-flop” between the two leaflets of a membrane. But we are NOT interested in the tortuous contortions a single one of them has to do to do so. Instead, we want to describe the many-lipid long-time stochastic fluxes that ensue. 2/26

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Markus Deserno @markusdeserno.bsky.social · 04/06/2026

While others are fascinated by different types of explosive revelations.

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Markus Deserno @markusdeserno.bsky.social · 28/05/2026

What in the fucking fuck is this supposed to mean? The mental rot is brain melting. What’s the goal here? “Sure, I have no health insurance, can’t pay for food and gas, and will never own a home. But thank GOD my representative can name check all obscure wide receivers from the early 2000s.”

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Markus Deserno @markusdeserno.bsky.social · 04/05/2026

I’ve just been at a screening of “Star Wars: The Empire Strikes Back,” with live music by the Pittsburgh Symphony Orchestra. And let me tell you: there is no better way to watch this movie or listen to this score. What a phenomenal show. What an amazing orchestra. Unforgettable. 🥰

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Markus Deserno @markusdeserno.bsky.social · 05/04/2026

This is in many ways a very good movie.

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Markus Deserno @markusdeserno.bsky.social · 23/03/2026

I’m sorry. This is a lengthy and whiny hot take. He makes a bunch of generalizations for which we rightfully call out modern columnists. Language changes, people change, modes of communication change—times change. Old people struggle to keep up and feel it’s a profound sign of doom.

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Markus Deserno @markusdeserno.bsky.social · 16/03/2026

📣 To celebrate Biophysics Week, the Membrane Structure and Function Subgroup (MSAF) of @biophysicalsoc.bsky.social will host a webinar on March 24 at 11am EDT. Our speakers are @mejohnson81.bsky.social, @ibudin.bsky.social, and Cecília Leal (not on 🦋). 🧪 👀 More info in the alt text! Please share! 🔄

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Markus Deserno @markusdeserno.bsky.social · 15/03/2026

It means they will never be able to send the kind of deep heartfelt all-American Christmas cards that he sends

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Markus Deserno @markusdeserno.bsky.social · 26/02/2026

The latest BPS Bulletin contains a beautiful obituary of Michael Saxton, who passed away in July 2025. Many thanks to Ingela Parmryd, Thomas Jue, and Anne Kenworthy for sharing their memories of Mike. He was a true fixture at all BPS meetings I remember, and he will be missed!

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Markus Deserno @markusdeserno.bsky.social · 22/02/2026

Today I had the great honor to hand the 2026 Thomas E. Thompson Award, the Prize of the BPS Membrane Structure and Function Subgroup, to Tobias Baumgart. 🏆 🎉 He’s on the right, in case that’s not clear! 😅 He gave a wonderful award lecture. A great conclusion of our Subgroup Saturday Symposium! 🧪

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Markus Deserno @markusdeserno.bsky.social · 27/01/2026

Many have already shared this powerful image by MJ.Hiblen, over on Insta under www.instagram.com/mjhiblenart/. It really makes me well up. May Renée and Alex rest in peace. 💔

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Markus Deserno @markusdeserno.bsky.social · 25/01/2026

How long until the word “appear” disappears? Not holding my breath.

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Markus Deserno @markusdeserno.bsky.social · 18/01/2026

Found a more “flattering” picture. This is Mitchum in “El Dorado,” where he plays sheriff J.P. Harrah, shown here as a drunkard who has given up on himself after an “affair of the heart” (we’re not even shown) ended poorly. Excellent movie, by the way.

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Markus Deserno @markusdeserno.bsky.social · 12/01/2026

“When kids weren’t as clumsy as nowadays, they used to build snowstorks in the winter.”

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