Abstract: Living systems from individual cells to entire tissues adopt diverse curved shapes, appearing on many length scales and commonly driven by active contractile stresses generated in the cell cytoskeleton. Yet, how these forces generate specific 3D forms remains unclear. By recreating the cell cytoskeleton from basic components, with precisely controlled composition and initial geometry, we demonstrate that the spontaneous buildup of stress gradients generated by these molecular motors drive shape deformation. We identify the shape selection rules that determine the final adopted configurations. These are encoded in the initial radius to thickness aspect ratio, likely indicating shaping scalability. These results provide insights on the mechanically induced spontaneous shape transitions in contractile active matter, revealing potential shared mechanisms with living systems across scales.

Abstract: Living organisms rely on chiral molecules, such as nucleic acids and proteins. A chiral molecule is not
superimposable on its mirror image, also known as its enantiomer, just like our right hand cannot be
superimposed on our left hand. Organisms contain only one enantiomeric form of a molecule, a
selectivity that has prevailed through evolution. The chiral induced spin selectivity (CISS) effect
studied by us [1], can explain why enantiomeric purity might provide an advantage in biology [2].
CISS is an electronic phenomenon in which electron transmission through chiral molecules depends on
the direction of the electron spin, a quantum mechanical property associated with its magnetic
moment. Thus, charge displacement and transmission in chiral molecules generates spin-polarized
electron distribution. This effect: enhance electron transfer in proteins, enable nano metric charge
separation, and explain biorecognition [3].
The effect also explains the high efficiency of multiple electrons process in biology (light
harvesting and respiration). This understanding can be utilized to increase the employment of green
energy by enhancing the efficiency and selectivity of the production process. Thus, improving in a
significant way the efficiency of electrolyzers, fuel cells, batteries, and solar cells [4].

Ron Naaman, Yossi Paltiel, David H. Waldeck; Chiral molecules and the electron spin; Nature Review Chemistry
3, 250–260 (2019) DOI: 10.1038/s41570-019-0087-1 (2019).
2. K. B. Ghosh, O. Ben Dor, F. Tassinari, E. Capua, S. Yochelis, A. Capua, S.-H. Yang, S. S. P. Parkin, S. Sarkar, L.
Kronik, L. T. Baczewski, R. Naaman, and Y. Paltiel; Enantio-Specific Interaction of Chiral Molecules with
Magnetic Substrates Science 360, 1331 10.1126/science.aar4265 (2018).
3. Yael Kapon, Abhijit Saha, Tal Duanis-Assaf, Thijs Stuyver, Amir Ziv, Tzuriel Metzger, Shira Yochelis, Sason
Shaik, Ron Naaman, Meital Reches, and Yossi Paltiel, Evidence for New Enantiospecific Interaction Force in
Chiral Biomolecules CHEM 7, 1–13 (2021). https://doi.org/10.1016/j.chempr.2021.08.002
4. Wenyan Zhang, Koyel Banerjee-Ghosh, Francesco Tassinari, and Ron Naaman, Enhanced Electrochemical Water
Splitting with Chiral Molecule-Coated Fe 3 O 4 Nanoparticles ACS Energy Lett. 3, 2308−2313 (2018).

Abstract: In ultra-peripheral PbPb collisions at the LHC, electromagnetic excitation via the Giant Dipole Resonance often produces single forward neutrons detected in the ATLAS ZDC, whose transverse momentum is sensitive to the excitation dynamics and nucleon momentum distributions inside the nucleus. For Run 3, ATLAS installed a transversely segmented Reaction Plane Detector with a mixed-depth, pan-flute fiber geometry, where traditional subtraction-based reconstruction becomes unstable in low-light single-neutron events. We present a two-stage neural-network reconstruction trained on Monte Carlo simulations that infers effective photon yields from raw RPD signals and then reconstructs the neutron transverse momentum, achieving significantly improved resolution and extending the sensitivity of forward-neutron measurements in ATLAS.

Abstract: TBA