# life: mudskippers use tail thrusting to help crutching to move on mud of various wetness.

<< ️At the water-land interface, amphibious fishes encounter wet flowable substrates made of granular solid-water mixtures, which can stay solid or flow like a fluid. As these substrates become wetter or drier, their yield strength (at which solid-fluid transition occurs) and cohesion (how sticky they are) both change, challenging locomotion. Despite substantial understanding of tetrapod locomotion on flowable substrates (mostly dry sand), we know little about how amphibious fishes cope with wet flowable substrates of various wetness. >>

<< ️Here, (AA) studied mudskippers on clay mud of controlled, variable wetness over the range where solid-fluid transition occurs. As mud became wetter, its strength decreased by 100-fold, leading the animal to sink deeper, with larger areas of body and fins contacting mud. By contrast, mud stuck most easily at intermediate wetness. The increased sinkage and contact and stickiness change caused more mud to stick to and pull against the animal on wetter mud. >>

<< ️(AA) also tested dry mud, which stuck to animal fins as its mucus dried. Despite these challenges, the mudskipper predominately used a conserved crutching gait on all except the wettest mud tested, with a modest performance reduction. When normal crutching became less effective, the animal assisted it with tail thrusting, by bending and straightening it to push downward and backward to generate additional thrust and lift, or even thrusting the tail to jump. >>

<< ️These observations suggest that mudskipper's crutching motor program is well adapted to its native muddy substrates but inflexible, with most novelty in tail use. >>

Divya Ramesh, Gargi Sadalgekar, Jiangqi Tan, et al. Mudskippers use tail thrusting to help crutching to move on mud of various wetness. arXiv: 2609.00564v1 [physics.bio-ph]. Sep 1, 2026.

https://arxiv.org/abs/2609.00564

Also: walk, walking, dance, transition, in https://www.inkgmr.net/kwrds.html 

Keywords: life, locomotion, walk, walking, dance, transitions, wet flowable substrates, granular solid-water mixtures, solid-fluid transitions, mudskippers. 

# gst: collective patterns generated by capillary surfers.

<< Millimeter-sized “surfers” can self-propel across a vibrating liquid surface, interacting with other surfers to create collective patterns. >>

<< Self-propelled objects can move in mesmerizing patterns. The collective movements of groups of such objects typically occur in one of two flow regimes: the inertial regime—think swirling schools of fish in water—or the viscous regime—think swarming colonies of bacteria in mucus. Some self-propelled objects can travel in both flow regimes, a possibility that is less explored. >>️

AA << have studied the motion of a new system of self-propelled objects that move in this intermediate regime, finding that the objects organize into several distinct and tunable motion patterns. >>️️

<< Pairs of self-propelled surfers observed by the team move in one of seven different patterns (the video shows five). These include the “orbit,” where a pair of surfers rotate around a central point; the “tailgate,” where one surfer closely follows another, head to tail in a linear path; and the “jackknife,” where a pair of perpendicular surfers rotate stern to stern around their collision point. >>

<< When only one surfer was present, these mismatched amplitudes propelled the surfer in the direction of its bow. When there were two surfers close to each other, interactions among the waves caused the surfers to either repel each other so that they moved in opposite directions or to come together so that they collectively traced one of seven distinct patterns. >>️

️

Maggie Hudson. Synchronized Surfing of Self-Propelled Particles. Physics 16, s156. Nov 7, 2023. 

https://physics.aps.org/articles/v16/s156

Ian Ho, Giuseppe Pucci, Anand U. Oza, Daniel M. Harris. Capillary surfers: Wave-driven particles at a vibrating fluid interface. Phys. Rev. Fluids 8, L112001. Nov 7, 2023.

https://link.aps.org/doi/10.1103/PhysRevFluids.8.L112001

Anand U. Oza, Giuseppe Pucci, Ian Ho, Daniel M. Harris. Theoretical modeling of capillary surfer interactions on a vibrating fluid bath. Phys. Rev. Fluids 8, 114001. Nov 7, 2023.

https://link.aps.org/doi/10.1103/PhysRevFluids.8.114001

Also: waves, particle, swarm, in: https://www.inkgmr.net/kwrds.html

Keywords: gst, waves, wave-wave, capillary waves, particles, self-propelled particles, fluid-particle interactions, wave-particle interactions

# drugs: from a slug (A. subfuscus) mucus: strong adhesives for wet surfaces

<< Adhesives that can bond strongly to biological tissues would have broad applications ranging from tissue repair and drug delivery to wound dressings and biomedical devices. However, existing tissue adhesives are far from ideal. >>

<< Achieving high adhesion energy requires the synergy of two effects. First, the adhesive should form strong bonds with the substrate. Second, materials inside either the adhesive or the substrate (or both) should dissipate energy by hysteresis. Tissue adhesives must also show compatibility with body fluids, as well as with cells and tissues. >>

AA << report the design of a family of tough adhesives for biological applications to meet those requirements. The design is inspired by a defensive mucus secreted by slugs (Arion subfuscus) that strongly adheres to wet surfaces. >>

J Li, AD Celiz, et al. Tough adhesives for diverse wet surfaces. Science  Jul 28, 2017; 357 (6349): 378-81. doi: 10.1126/science.aah6362

http://science.sciencemag.org/content/357/6349/378 

Sticky when wet: Strong adhesive for wound healing. Slug-inspired, flexible medical bio-glue sticks to wet surfaces without toxicity. Wyss Institute for Biologically Inspired Engineering at Harvard. July 27, 2017.

https://www.sciencedaily.com/releases/2017/07/170727141508.htm

# rmx-s-immuno-n-ethnomed: mucus, the first line

T. Mohanty, J. Sjogren,  et al. A novel mechanism for NETosis provides antimicrobial defense at the oral mucosa. Blood, 2015; 126 (18): 2128 DOI: 10.1182/blood-2015-04-641142

"Mucus: The first line of defense."
ScienceDaily, 6 November 2015.

http://www.sciencedaily.com/releases/2015/11/151106062716.htm

a questo proposito qui di seguito il link di una "nota" a fraseggio "quasistocastico", non recentissima ma sempre attuale ...

http://inkpi.blogspot.it/2006/11/2086-pain-suppressive-effect.html