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John Sebastian

@johnseb.bsky.social
133 followers 226 following 15 posts

Fluid Mechanics, etc john-seb.github.io

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Reposted by John Sebastian
Meroz Lab @merozlab.bsky.social · 24/09/2026
🌱🪩 Optical illusions in plants? New paper @pnas.org: Nonlinear distributed sensing of light patterns leads to perceptual distortions in plants, or any distributed system tinyurl.com/5x79sxaj 📽️ opposing lights cancel, plant grows toward weaker light 🤩 R Kempinski, @amirporat.bsky.social, M Rivière
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LeidenForce @leidenforce.bsky.social · 24/08/2026
🔬 At the 13th #CMiF #SummerSchool, Cheikh, Gauri and Lorena presented their research on the #Leidenfrost effect and, more importantly, put their results in front of researchers outside the project. One of the most useful exercises in a PhD. #LeidenForce #DTU
Cheikh gives an oral presentation during a summer school. Part of a slide is visible behind him, showing a part of a graph.Gauri Patki presents her poster during the CMiF poster session. She stands beside her poster and discusses her research with the people attending the session.Lorena Victoria-García gives an oral presentation to the audience during the CMiF summer school.
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Saverio E. Spagnolie @sespagnolie.bsky.social · 21/08/2026
Including this mass asymmetry in the reduced order model produces a system which is related to the 4D Lorenz system, or the Malkus-Robbins system. Because so much is known about the Lorenz system, these connections allow us to predict behavior transition (bifurcation) times, and more. (7/10)
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Anja Geitmann @geitmannlab.bsky.social · 19/07/2026
Why do primary plant tissues hold their shape? We are told it's because of turgor pressure—but how does that work mechanically? We investigated how pressurized cylindrical structures support themselves. Read here: doi.org/10.1039/d6sm... Funded by @hfspo.bsky.social www.plantbiomechanics.net
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Proceedings of the National Academy of Sciences @pnas.org · 18/07/2026
A reverse sprinkler draws in fluid rather than ejecting it. The geometry of the reverse sprinkler’s arms drives its rotation: specifically, the flux in the angular momentum of the fluid being injected into the central hub of the sprinkler. In PNAS: ow.ly/K1C650Zoa3H
CAPTION: Flows of water coming into a reverse sprinkler, visualized using particles, and false-colored. 
CREDIT: New York University's Applied Math Lab
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Prakash Lab @ Miami @vprakashlab.bsky.social · 23/06/2026
🎨🔬 Can techniques from the arts become tools for scientific discovery? Our new preprint introduces glass-based physical models for studying tissue mechanics, bridging art, physics, engineering, and biology! 😀 📄 arxiv.org/abs/2606.22281
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Joel Marthelot @joelmarthelot.bsky.social · 13/06/2026
The molecular origin of this rapid softening remains unknown. Future studies and new genetic tools are needed to uncover the signals driving the ultra-fast mechanical remodeling of the cell wall. Full paper in @science.org: www.science.org/doi/10.1126/...
science.org
Fast cell wall softening causes Venus flytrap closure
Plants can move rapidly without muscles, as seen in the Venus flytrap’s snapping lobes—a long-standing puzzle in plant biomechanics. Trap closure involves an elastic instability, but the active mechan...
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Alain Goriely @alaingoriely.bsky.social · 15/05/2026
I am looking for a Post-doc in Oxford to work with me on morphogenesis at the cellular scale, with particular emphasis on growth processes and their mechanical and dynamical consequences. Please circulate my.corehr.com/pls/uoxrecru... This bristle is created by a single cell! Let's model it.
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John Sebastian @johnseb.bsky.social · 12/04/2026
I’ve now heard from the 10th person who appreciated the nerd callout in the footnote!
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Meroz Lab @merozlab.bsky.social · 03/04/2026
Preprint 🌱 Plants build nonlinear vectorial representations of light patterns! Surprising results: Opposing cues cancel, so plants grow towards a weaker tie-breaker light. Plants respond to sum of transduced signals, not physical sum of light: optical “illusions”! 🪩 tinyurl.com/44f83xh8
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Meroz Lab @merozlab.bsky.social · 30/03/2026
🌱 “To twine or not to twine?” Preprint 🪩 Plants use inherent circular movements (circumnuations) for active sensing of support mechanical stability (eg whisking 🐭), twining occurs at a torque threshold. Heroic experiments by Amir Ohad, fancy simulations @amirporat.bsky.social: tinyurl.com/2syh4ny3
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Physics Today @physicstoday.aip.org · 20/03/2026
Capitalizing on a mechanoelectrical mechanism that arises from the spines’ structure could yield useful sensors for marine environmental monitoring and other applications. #physics #biophysics
physicstoday.aip.org
Sea urchin species discerns surroundings with electrically responsive spines
Capitalizing on a mechanoelectrical mechanism that arises from the spines’ structure could yield useful sensors for marine environmental monitoring and other applications.
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John Sebastian @johnseb.bsky.social · 13/03/2026
"Nothing happens to anyone that he is not fitted by nature to bear" - Maximus 🧪⚛️🎢🧮
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John Sebastian @johnseb.bsky.social · 12/03/2026
✐ᝰ ✏️ 🧪⚛️🎢🧮
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Bhamla Lab @ Georgia Tech @bhamlalab.bsky.social · 11/03/2026
Comics by Caroline Hu here
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Elise Cutts @elisecutts.bsky.social · 10/03/2026
I decided to highlight this study for two reasons: 1) It is fun. There's an experiment involving "pencil gladiators." And spikes across scale. Need I say more. 2) It's a good reminder that not everything in biology exists to serve some evolutionary purpose. Biology is also physics.
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Elise Cutts @elisecutts.bsky.social · 10/03/2026
To make a long story short: the universal stabby curve cometh from mechanical weathering. It is not some evolved optimum solution for stabbing, it is just the shape you get if you expose a pointy thing to the elements for long enough.
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Elise Cutts @elisecutts.bsky.social · 10/03/2026
Spikes are a lie. They are not as spiky as they might appear. Across nature, spikes end in a blunt, paraboloid curve — the universal curve of stabbiness. And that's true at EVERY SCALE. From microscopic to narwhal. Why? Whence cometh the universal stabby curve? Science has your answers: 🧪
reviewertoo.com
Stingers and spikes across nature have the same shape. Here's why.
Not everything in biology evolved for a purpose.
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Etienne Jambon-Puillet @ejambonp.bsky.social · 09/03/2026
Very cool! It always amazes me how different problems can look very similar once put into equations. The sublimation of sharp tips also yields a curvature decreasing as t^(-1/2) because the receding velocity scales with the curvature locally (doi.org/10.1038/s414...).
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Kaare H. Jensen @jensen-research.bsky.social · 09/03/2026
Our new paper is now out in PNAS: "The geometry of Nature’s stingers is universal due to stochastic mechanical wear." doi.org/10.1073/pnas... . Original artwork by John Sebastian
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John Sebastian @johnseb.bsky.social · 09/03/2026
On ’pointless’ optima in Nature! Out now in @pnas.org From #DTU #DK Thanks @villumfonden.bsky.social 🧪 ⚛️
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Youjin Shin | 신유진 @helloeujin.bsky.social · 27/02/2026
🎮 pokemon tree of life for pokémon's 30th anniversary, explore a visualization and field guide to 1,000+ pokémon. what inspired them, where they came from, and how they connect. 포켓몬 30주년, 1,000개 이상의 포켓몬을 시각화했습니다! ➡️ str.sg/viz-poke30
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Alban Sauret @albansauret.bsky.social · 23/02/2026
It took me quite some time, but the article following a talk at the DFD 2024 is finally online! Clogging is widespread, but the associated physics remains poorly understood. I am trying to give a (biased) view and some general knowledge here: doi.org/10.1103/rfk8...
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Alban Sauret @albansauret.bsky.social · 18/02/2026
Our new paper, led by @ramsudhirsharma.bsky.social (with Alexandre Leonelli, Kevin Zhao, Eckart Meiburg), has been published in @apsphysics.bsky.social PRL. We revisit hourglasses/silos and ask what really sets the discharge rate. See more here: doi.org/10.1103/3g2f-nslz
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John Sebastian @johnseb.bsky.social · 30/01/2026
🧪⚛️
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Kaare H. Jensen @jensen-research.bsky.social · 23/01/2026
We’ve been putting together a small device to study flow through pores, where geometry matters and minor imperfections can make or break the experiment. The goal is simple to state and nontrivial to execute. One early prototype looks, quite unintentionally, like a Picasso: a face, a pair of eyes.
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Brandon Moore, PhD @rando.insalubrio.us · 08/01/2026
@leakey77.bsky.social and colleagues combined laser confocal microscopy with gas exchange measurements to enable the real-time observation of living plant stomata! 🧪 academic.oup.com/plphys/artic...
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Alban Sauret @albansauret.bsky.social · 06/01/2026
3D printing meets fluid mechanics! Thrilled to see our Annual Review of Fluid Mechanics article on direct-ink writing featured by @utknoxville.bsky.social. With Brett Compton & @raytyler.bsky.social : tickle.utk.edu/mae/news/com... @annualreviews.bsky.social @univofmaryland.bsky.social
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Charlotte Brannon @cbrannon.bsky.social · 23/12/2025
My first PhD paper with Prakash Lab is out in its final form! Here we uncover the many folded forms of Placozoa and how cilia unfold them. Enjoy the paper and our stop motion summary of this story! www.pnas.org/doi/10.1073/...
pnas.org
PNAS
Proceedings of the National Academy of Sciences (PNAS), a peer reviewed journal of the National Academy of Sciences (NAS) - an authoritative source of high-impact, original research that broadly spans...
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Prakash Lab at Stanford @prakashlab.bsky.social · 04/01/2026
Please fill short application form to be considered as a “global cohort” student. No fees, no restrictions. We are looking for passionate individuals that like to work in teams with a “frugalist” philosophy to find scalable solutions to global challenges. Deadline: 9th January lnkd.in/gxftkgz
lnkd.in
LinkedIn
This link will take you to a page that’s not on LinkedIn
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Prakash Lab at Stanford @prakashlab.bsky.social · 04/01/2026
After all the anticipation - FrugalScience 2026 - a collaborative global collective is LIVE again for 2026 season. www.frugalscience.org Apply - deadline 9th January (midnight)
frugalscience.org
Frugal Science
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Prakash Lab at Stanford @prakashlab.bsky.social · 19/12/2025
(2/n) In our latest paper in PNAS, led by an incredible graduate student @cbrannon.bsky.social - we show a bizarre world of "cellular plate tectonics". Imagine a self-folding origami with a mind of its own. A living sheet that does not need any instructions to fold.. www.pnas.org/doi/10.1073/...
pnas.org
Cilia-driven epithelial folding and unfolding in an early diverging animal | PNAS
Multicellular organisms utilize epithelial folding to achieve remarkable three-dimensional forms. During embryonic development, stereotypical epith...
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Kaare H. Jensen @jensen-research.bsky.social · 19/12/2025
Reflections #FluidsFriday
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John Sebastian @johnseb.bsky.social · 12/12/2025
🧪⚛️ A counterintuitive finding: doi.org/10.1017/jfm.... (Physics-1, John-0)
doi.org
Experiments on a sphere settling towards a boundary in a viscous liquid under the influence of a magnetic force | Journal of Fluid Mechanics | Cambridge Core
Experiments on a sphere settling towards a boundary in a viscous liquid under the influence of a magnetic force - Volume 1024
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Adam Summers @fishguy.bsky.social · 11/12/2025
A nice write up of the Science/Poetry meeting we have every year here at Friday Harbor Labs. salish-current.org/2025/12/11/w...
salish-current.org
Where words meet the natural world
An annual symposium in Friday Harbor explores what happens when poetry and science coalesce.
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Kaare H. Jensen @jensen-research.bsky.social · 05/12/2025
William Pickard developed an elegant analytical solution to describe low-Reynolds-number flow in long cylindrical cells. This setup resembles the classic Couette flow, but in this case, the velocity depends on the angle and the radial position (normalized by the cell radius) buff.ly/RcuIAyW
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Kaare H. Jensen @jensen-research.bsky.social · 28/11/2025
It's #FluidsFriday, and we're featuring another sample from the hydrodramatic toy collection. A rising Taylor bubble generates a swirling flow inside a sealed cylindrical tube.
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John Sebastian @johnseb.bsky.social · 26/11/2025
🧪 ⚛️ 🎢 👩‍🔬
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Kaare H. Jensen @jensen-research.bsky.social · 25/11/2025
Roses don’t just defend themselves. Their prickles are geometrically ideal for gripping surfaces, supporting vertical growth, and, when needed, creating lacerations that deter herbivores. Students - join us to investigate how biological form and physical law work together!
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Alban Sauret @albansauret.bsky.social · 25/11/2025
I am looking to hire PhD students to join our Multiphase & Multiscale Flow Lab in Mechanical Engineering @univofmaryland.bsky.social Background in ME, Physics, ChemE, Civil (or related), interest in fluid mechanics/soft matter, and hands-on lab work are key. Please help spread the word!
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Meroz Lab @merozlab.bsky.social · 02/11/2025
New paper!💡 Amir Ohad developed this nifty setup to measure weak forces generated by freely moving plants, based on the deflection of a pendulum (straw from the cafeteria 😎), which does not require any tethering of the plant: academic.oup.com/jxb/advance-... Plant-obstacle interactions here we come!
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Prakash Lab at Stanford @prakashlab.bsky.social · 24/10/2025
“Cellular Olympics” our catalog of freeky ultra fast cellular superhero’s is freely available “Ann Rev of microbiology” www.annualreviews.org/content/jour... This is a compilation of world’s fastest single cell organisms - enjoy this buffet of rare delightful protists with mind bending speeds. 🧪
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Prakash Lab at Stanford @prakashlab.bsky.social · 31/10/2025
An intimate conversation about what drives me every day in “sharing experience” of science by getting tools of science in hands of kids everywhere. themicroscopists.bitesizebio.com/episodes/man...
themicroscopists.bitesizebio.com
The Microscopists | Manu Prakash (Stanford University)
We're thrilled to bring you this episode of The Microscopists with an absolute force in accessible science and microscopy innovation—Manu Prakash of Stanford University.Manu shares the origin of th...
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Prakash Lab at Stanford @prakashlab.bsky.social · 18/10/2025
Congrats @laurentformery.bsky.social Often people ask why we chose to work on a certain problems and a simple answer for us in this case - it’s beautiful. If you want to learn the magic of building crystalline « gems » inside the body - see our latest paper at www.biorxiv.org/content/10.1...
biorxiv.org
Algorithmic construction of topologically complex biomineral lattices via cellular syncytia
Biomineralization is ubiquitous in both unicellular and multicellular living systems [[1][1], [2][2]] and has remained elusive due to a limited understanding of physicochemical and biomolecular proces...
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Proceedings of the National Academy of Sciences @pnas.org · 17/10/2025
Sharpen your knives! High-speed video analysis reveals that blunt knives and faster cutting speeds release more eye-irritating droplets from onions by building pressure under the onion’s skin before the ejection of the tear-inducing aerosols. In PNAS: ow.ly/5rc750Xcvhj
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Jessica C. Huss @j2huss.bsky.social · 08/10/2025
One day in the lab, we accidentally discovered that the spines of a cactus 🌵 straighten when exposed to fog. I was intrigued and so were my collaborators. How does this work and what can be gained from it? Here are some of the answers in our new preprint: doi.org/10.1101/2025...
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Alban Sauret @albansauret.bsky.social · 14/08/2025
Our new study from Joanne Steiner’s PhD work and with C. Morize, P. Gondret, and I. Delbende has just been published in Phys. Rev. Fluids! We study vortex rings generated when a disk moves toward or away from a wall. doi.org/10.1103/ynxr...
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Bhamla Lab @ Georgia Tech @bhamlalab.bsky.social · 23/07/2025
What a great discovery and story!!
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Sainsbury Laboratory Cambridge University (SLCU) @slcuplants.bsky.social · 23/07/2025
🚨Don’t miss out! Last weeks left to register for the Plant Computational Biology Workshop 2025, sponsored by @cambup-lifesci.cambridge.org 🌱 📆Deadline 31 July - www.slcu.cam.ac.uk/computationa... #ComputationalBiology #PlantSci
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Alex Klotz @aklotz.bsky.social · 20/07/2025
Inverted Wolfram Alpha logo spotted at St. Mark's basilica in Venice
wolfram alpha logo (dodecahedral star thing) and a similar floor tile one from Venice
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