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Joel Marthelot

@joelmarthelot

BioSoftActuation @ CNRS Aix-Marseille Univ https://biosoftact.wordpress.com

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23.11.2024
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Latest posts by Joel Marthelot @joelmarthelot

Delighted this paper is out! Soft solids fracture in complex ways. Can we control it using structure and activity? Yes, using defects that localize energy injection for targeted failure! Amazing work combining exp, theory & ML by Sheng Chen and collab with Murrell lab (Yale).

27.02.2026 19:19 πŸ‘ 12 πŸ” 5 πŸ’¬ 0 πŸ“Œ 0
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Break It To Make It: How Fracturing Sculpts Tissues and Organs | Quanta Magazine Growing tissues can crack, break, and dissociate to form structures that can later withstand immense forces.

Sometimes, the only way to build back up is to let everything fall apart. This is certainly true at the cellular level. www.quantamagazine.org/break-it-to-...

27.02.2026 15:43 πŸ‘ 48 πŸ” 22 πŸ’¬ 0 πŸ“Œ 2
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Great to see our paper on light-intensity dependent swimming patterns in #Chlamydomonas out now in Phys Rev Lett. as an Editors' suggestion! With a nice commentary by @philipcball.bsky.social.

Chlamy actively modulate the beat planes of their #cilia!
journals.aps.org/prl/abstract... #protistsonsky

20.02.2026 16:54 πŸ‘ 73 πŸ” 24 πŸ’¬ 1 πŸ“Œ 1
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Break to build: fracture as a unifying morphogenetic strategy Summary: This Review presents mechanical fracture as a unifying morphogenetic strategy and describes how developmental systems actively exploit mechanical fracture to drive morphogenesis, reproduction...

Our latest with @torres-sanchez.bsky.social journals.biologists.com/dev/article-...
Breaking isn’t always a bad thing! Think of birth, seed release...
We highlight how living tissue not only tolerates fractures but actively fracture to grow, shape, reproduce, or adapt – across species and scales.

11.02.2026 02:04 πŸ‘ 49 πŸ” 15 πŸ’¬ 3 πŸ“Œ 3
Fluorescent neurons on black background. We're hiring! PhD Student

Fluorescent neurons on black background. We're hiring! PhD Student

🚨 We are #hiring a PhD Student to study cerebellum-like circuits in #Drosophila.

Please spread the word!

www.groschner-lab.org/join

#Neuroscience #PhD

14.02.2026 21:42 πŸ‘ 15 πŸ” 18 πŸ’¬ 0 πŸ“Œ 1
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Our article on multilayer inflatables has been published! A physics-computer graphics collab in which we introduce a new type of thin-sheet balloons and discuss their shape programming 🎈 @espciparispsl.bsky.social @pmmh-lab.bsky.social
dl.acm.org/doi/pdf/10.1...

10.02.2026 13:45 πŸ‘ 3 πŸ” 1 πŸ’¬ 1 πŸ“Œ 0
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Excited to share my first PhD preprint! w/ SΓΆren Kannegieser and @anna-stoeckl.bsky.social @insect-vision.bsky.social

We investigated how hawkmoths coordinate lateralized sensory and motor control for appendage guidance, revealing similar control principles to vertebrates doi.org/10.64898/202...

02.02.2026 10:27 πŸ‘ 54 πŸ” 13 πŸ’¬ 0 πŸ“Œ 2

The paper is finally out in JFM πŸŽ‰πŸŽŠ: doi.org/10.1017/jfm....
Below is the thread summary of last year πŸ‘‡

03.02.2026 14:20 πŸ‘ 6 πŸ” 2 πŸ’¬ 0 πŸ“Œ 0
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Really excited to share our new paper in @nature.com! We uncovered how a physical instability of the cytoplasm coupled with the cell cycle drives cytoplasmic partitioning in early embryos #zebrafish #drosophila. Read more in this🧡 www.nature.com/articles/s41... 🀩
@poldresden.bsky.social @mpi-cbg.de

28.01.2026 16:10 πŸ‘ 204 πŸ” 67 πŸ’¬ 4 πŸ“Œ 10
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Super happy to share the exciting work of Emma Legait, showing how neighbourhood composition determines cancer stem cell fate in hierarchical tumours. A great and long-standing collaboration with @cedricmaurange.bsky.social

www.biorxiv.org/content/10.6...

28.01.2026 13:54 πŸ‘ 14 πŸ” 6 πŸ’¬ 1 πŸ“Œ 0
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More about our latest collaborative work...

β€œArchitectural Swarms for responsive faΓ§ades and creative expression” is now published in Science Robotics @science.org ! Read it here: science.org/doi/10.1126/scirobotics.ady7233.

27.01.2026 18:36 πŸ‘ 11 πŸ” 3 πŸ’¬ 1 πŸ“Œ 0
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Job alert🚨I am advertising a 2-year postdoctoral position to work on the mathematics of plant morphogenesis @mpipz.bsky.social. Candidates with interests in mathematical modelling, mechanics, or biophysics are strongly encouraged to apply. 🌱Reposts are appreciated!

jobs.mpipz.mpg.de/jobposting/4...

22.01.2026 14:34 πŸ‘ 25 πŸ” 27 πŸ’¬ 0 πŸ“Œ 2
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Our new paper (with @biotay.bsky.social) is out and on the cover story of @currentbiology.bsky.social !!!! Veronika, a Carinthian mountain cow flexibly uses a β€œmulti-purpose tool” to scratch herself. A video and more information will follow in the comments.
www.cell.com/current-biol...

19.01.2026 16:07 πŸ‘ 353 πŸ” 125 πŸ’¬ 10 πŸ“Œ 31
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Excited to share Alison's @alisonkickuth.bsky.social paper from the lab out in @nature.com this week! We uncovered how a mechanical ratchet mechanism drives cytokinesis in early #zebrafish embryos. Read more in this thread 🧡 and at www.nature.com/articles/s41... 🀩
@poldresden.bsky.social @mpi-cbg.de

07.01.2026 16:02 πŸ‘ 150 πŸ” 60 πŸ’¬ 8 πŸ“Œ 5
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The rise of brain folds Differences in brain folding between species can be explained by variations in initial brain size, shape and cortical growth rate, rather than by different folding mechanisms.

The most recognisable feature of the human brain is its folds. So why do other animals’ brains look so different?

03.01.2026 11:01 πŸ‘ 28 πŸ” 10 πŸ’¬ 0 πŸ“Œ 0
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Check out our latest preprint on the cellular mechanical basis of Voronoi tessellations in epithelia! This biophysics study is inspired by disordered tessellations observed in zebrafish hearts πŸ€“πŸŸπŸ’™ #SulaimaanLim #ChiuFanLeeLab

arxiv.org/html/2512.13...

19.12.2025 07:25 πŸ‘ 25 πŸ” 9 πŸ’¬ 0 πŸ“Œ 0
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Non-motile microbes are not prisoners of diffusive transport. Just their metabolic activity can be sufficient to stir up the ambient fluid and cause explosive long-range dispersal -- a "metabolic firework".

Our latest work -- arxiv.org/abs/2512.16288

19.12.2025 07:04 πŸ‘ 27 πŸ” 6 πŸ’¬ 2 πŸ“Œ 1
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The study shows how individual fingerprint ridges deform when we touch different textures, revealing how subtle stretching and shifting along the ridge flanks may drive our remarkably fine tactile sensitivity.
buff.ly/4z67Vf1

12.12.2025 21:03 πŸ‘ 12 πŸ” 7 πŸ’¬ 0 πŸ“Œ 1
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Quantifying grain boundary deformation mechanisms in small-grained metals - Nature Experimental observations in small-grained polycrystals suggest a new concept of considering metallic grain boundaries not as defects but as separate defect-containing lattices, providing a potential explanation for the deformation behaviour of nanocrystalline metals.

Nature research paper: Quantifying grain boundary deformation mechanisms in small-grained metals

go.nature.com/48vtZcJ

10.12.2025 19:23 πŸ‘ 12 πŸ” 1 πŸ’¬ 1 πŸ“Œ 0
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As humanity pumps carbon dioxide into the atmosphere, the ocean absorbs about a quarter of it. This exchange happens largely through bubbles created by breaking waves.
fyfluiddynamics.com/?p=26003

09.12.2025 17:00 πŸ‘ 4 πŸ” 1 πŸ’¬ 0 πŸ“Œ 0
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Researchers propose a method of manipulating small particles by using acoustic levitation and electrostatic charging, leveraging electrostatic repulsion and acoustic attraction to expand and collapse structures as needed. In PNAS: https://ow.ly/LKIK50XC71T

05.12.2025 02:00 πŸ‘ 3 πŸ” 2 πŸ’¬ 0 πŸ“Œ 0
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Where on earth is the best laboratory to demonstrate the beauty of fluid dynamics?

Actually, it’s not on earth. Here is the story of the soft cell.

And a longer read: www.maths.ox.ac.uk/node/74308

19.11.2025 15:40 πŸ‘ 74 πŸ” 20 πŸ’¬ 3 πŸ“Œ 4
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Active droplets are fundamental in cell biology and origin of life. With Jonathan Bauermann, @boekhovenlab.bsky.social, Frank JΓΌlicher, and @m-pol.bsky.social, we show that a critical transition influences their size, morphology, ripening and division propensity

journals.aps.org/prx/abstract...

15.11.2025 11:28 πŸ‘ 26 πŸ” 7 πŸ’¬ 1 πŸ“Œ 0
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Pure Hydrodynamic Instabilities in Active Jets of Puller Microalgae Using phototaxis to control cell orientation, various instabilities can be induced in jets of motile microalgae.

Our work on hydrodynamic instabilities in active jets is on the cover of PRL this week!
journals.aps.org/prl/abstract...

A dialogue between experiment and theory, where we use light to control active suspensions and show how they can be destabilized by their self-generated flows

11.11.2025 09:42 πŸ‘ 5 πŸ” 2 πŸ’¬ 1 πŸ“Œ 0
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Active Matter Gets Solid Researchers have determined the mechanical properties of a tiny beam made of active particles, laying the groundwork for future micromachines.

Coaxing tiny, self-propelled particles into cohesive structures provides one route to making micromachines. Taking a step in that direction, researchers have measured and analyzed the mechanical properties of materials assembled from active particles.

03.11.2025 18:03 πŸ‘ 11 πŸ” 2 πŸ’¬ 0 πŸ“Œ 0
Workshop poster

Workshop poster

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Excited to be at ICTS for the school on Geometry, Mechanics and the Physics of Growth, co-organized with Ganga Prasath (IITM) and @joelmarthelot.bsky.social (Aix-Marseille)! Fantastic start with a lecture on continuum elasticity by @abigailplummer.bsky.social (BU)

03.11.2025 05:26 πŸ‘ 23 πŸ” 4 πŸ’¬ 1 πŸ“Œ 0
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Really excited to present the results of a fantastic collaboration with Jesse Veenvliet @jesseveenvliet.bsky.social @mpi-cbg.de @poldresden.bsky.social 🀩

We find a unique mechanism for body axis elongation in mammals, different from other vertebrate species

➑️ www.biorxiv.org/content/10.1...

28.10.2025 08:24 πŸ‘ 142 πŸ” 47 πŸ’¬ 6 πŸ“Œ 3
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Static electricity may be key to helping a tiny roundworm latch onto its insect hosts.

Like a heat-seeking missile, the parasite zooms up to 10 millimeters in the air before getting yanked toward its target by nothing more than the electrostatic charge of its host. https://scim.ag/3WKFVjZ

21.10.2025 22:35 πŸ‘ 69 πŸ” 21 πŸ’¬ 4 πŸ“Œ 2
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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: https://ow.ly/5rc750Xcvhj

16.10.2025 23:00 πŸ‘ 12 πŸ” 4 πŸ’¬ 0 πŸ“Œ 0

Appreciate Quanta for shining a light on our joint work with Simon Gsell, Sham Tlili (@shamtlili.bsky.social), and Matthias Merkel (@merkellab.bsky.social).

11.10.2025 07:04 πŸ‘ 36 πŸ” 14 πŸ’¬ 2 πŸ“Œ 1