https://t.co/2UirQp469t A short tribute to Mal Ruderman, written with Ashley Bransgrove, Yuri Levin, and with contributions from many of Mal's @PhysicsColumbia and @ColumbiaAstro colleagues [photo of Mal's last lecture at @ColumbiaThea ]

Obituary of Dennett with @drmichaellevin as a small homage to Dan

All this thanks to phenomenally curious and talented Steven G. Harrellson @steveharrellson and Michael S. Delay @demystifysci , other members of Sahin lab, and our collaborators Adam Driks, Jonathan Dworkin, and Howard Stone. 15/n

Fun fact: If you squeeze a hydration solid, nearly 100% of the mechanical energy is stored in water, i.e., in hydration forces. The percentage goes down to about 80% in super dry conditions. Thanks to Kislon Voïtchovsky for this viewpoint. 14/n

The energy harvesting cycle can run backwards to harvest water from the atmosphere by putting in mechanical work into hydration solids. This approach might avoid heating and cooling cycles in current water harvesters. 13/n

The hydration solid is ideal for converting/harvesting energy from changes in relative humidity or evaporation. There is a direct and efficient two-way coupling between external mechanical forces into the chemical potential of water. 12/n

The hygroelastic transition could allow creating rigid elastic materials that can be highly effective at dissipating energy. This is a combination that is hard to come by. 11/n

The hygroelastic transition differs from the glass transition and the poroelastic transition. Unlike poroelastic behavior, it exhibits a large change in elastic modulus, and unlike glassy behavior the timescale of the transition scales with a characteristic length scale. 10/n

The paper reports a new kind of transition in materials, called the hygroelastic transition. At short timescales, the elastic modulus of the material increases by about an order of magnitude. We provide evidence that the transition originates from jamming of water molecules. 9/n

The paper reports extremely strong nonlinear elasticity with an exponential stress-strain relationship. 10% compression increases tangent modulus by 10-fold. This property can lead to materials with new capabilities. 8/n

There is a simple equation that describes many equilibrium properties of biological matter regardless of their biomolecular composition. It is like the ideal gas law describing all sorts of gasses with one formula, but perhaps richer in terms of the phenomena it describes. 7/n

Physicists enjoy finding unifying principles. A single principle, the basis of hydration solids, unifies many seemingly independent phenomena, both equilibrium and nonequilibrium, across many organisms from different kingdoms of life. The degree of unification is tremendous. 6/n

If you know some molecular scale properties of water, you can predict equilibrium and nonequilibrium properties of biological matter with simple math. Just add the characteristic dimensions of biomolecules. This idea seems to work for wood, bacterial spores, and fingernails. 5/n

The hydration solid is a highly unusual solid. The macroscopic properties of the solid come from the microscopic properties of water. Pore water flows like a viscous fluid at the nanoscale but acts like an elastic solid at the macroscale. 4/n

Hydration solids offer a physical basis for why life thrived on land but not in water. Desiccation, gravity, winds, and the solid environment makes land inhospitable to life. Terrestrial life needed a rigid solid to overcome these challenges. 3/n

A new class of solid matter: We found a class of solids called the hydration solids that complement the covalent, metallic, and ionic solids that make up most of our world. Many forms of biological matter, perhaps most by mass, could be hydration solids. 2/n

Hydration solids paper is now on the pages of Nature. This work has some fundamental implications about the physics of solid matter, terrestrial life, and water, along with some potential applications. I will try to break these down in a thread. 1/n https://t.co/yP8sVHheDy

V. Adrian Parsegian (1939-2023) was a former and first editor of Biophysical Journal, a former president of the Biophysical Society and the founding editor of the Biophysical Discussions. Among the founders of the modern theory of interactions between biological macromolecules.

"if I have seen further, it is by standing on the shoulders of giants." says Isaac Newton. V. Adrian Parsegian was one of those giants. He left us, but his ideas and discoveries will continue to help us see further.

Hydration Solids at @Columbia ! "...water not only endows biological matter with fluidity but...give rise to a ‘hydration solid’ with unusual properties. A ... distinct class of solid matter. ..." https://t.co/waE8OglhMg @Nature @Extremebio_Labs