Integrated Calendar

Wetting describes the ability of liquids to maintain contact with a solid surface, a phenomenon that is ubiquitous in nature.1 However, in engineering and medical applications, contact of solid surfaces with aqueous media leads to undesirable phenomena such as corrosion, chemo- and biofouling, which have extremely negative economic, health, and environmental impacts. Therefore, control of wetting on solid surfaces is key to mitigating its detrimental effects. The latter can be achieved by minimizing the contact of the solid substrate with aqueous media, so-called superhydrophobic surfaces (SHS). Although SHS have been studied for decades to overcome wetting challenges,2 they are still rarely used in engineering applications.
When immersed underwater, a special type of SHS can trap air on its surface, so-called air plastron, also known as an aerophilic surface. To date, plastrons have been reported to be impractical for underwater engineering due to their short lifetime. Here, I will describe aerophilic surfaces made of titanium alloy (Ti) with an extended lifetime of plastron conserved for months underwater.3 The extended methodology was developed to unambiguously describe the wetting regime on such aerophilic surfaces since conventional goniometric measurements are simply impractical. My aerophilic surfaces drastically reduce the adhesion of blood, and when immersed in aqueous media, prevent the adhesion of bacteria, and marine organisms such as barnacles, and mussels. Applying thermodynamic stability theories, we describe a generic strategy to achieve long-term stability of plastron on aerophilic surfaces for demanding and hitherto unattainable applications.

(1) Quéré, D. Wetting and Roughness. Annual Review of Materials Research 2008, 38 (1), 71-99.
(2) Cassie, A. B. D.; Baxter, S. Wettability of porous surfaces. Transactions of the Faraday Society 1944, 40, 546-551.
(3) Tesler, A.B.;* Kolle, S.; Prado, L.H.; Thievessen, I.; Böhringer, D.; Backholm, M.; Karunakaran, B.; Nurmi, H.A.; Latikka, M.; Fischer, L.; Stafslien, S.; Cenev, Z.M.; Timonen, J.V.I.; Bruns, M.; Mazare, A.; Lohbauer, U.; Virtanen, S.; Fabry, B.; Schmuki, P.; Ras, R.H.A.; Aizenberg, J.; Goldmann, W.H. Long-Lasting Aerophilic Metallic Surfaces Underwater. Nature Materials 2023, accepted. *Corresponding author

Transient receptor potential (TRP) channels are a large, eukaryotic ion-channel superfamily that control diverse physiological functions. To date, more than 210 structures from over 20 TRP-channels have been determined, all are tetramers. Using high-speed atomic force microscopy (HS-AFM), a pioneering technique capable of “filming” single-molecule proteins, we discovered a rare and transient pentameric state for TRPV3, and determined the pentamer structure using single-particle cryo-EM. Our results suggest that the pentamer relates to the pore-dilated state, a structurally-elusive state characterized by increased conductance and permeability to small molecules. These findings lay the foundation for many new directions in ion-channel research, and demonstrate the strength of HS-AFM in discovering transient and rare states of proteins.

Rubisco is the enzyme that catalyzes the first step of carbon sequestration during photosynthesis. Despite the massive flux of CO2 passing through this active site over billions of years, it remains a primary rate-limiting step due to its relatively slow kinetics. We have developed an E. coli strain that couples doubling rate to rubisco biochemical parameters. Using this strain we have characterized all possible point mutations of a model bacterial rubisco (~9000 mutants). This deep mutational scan has allowed us to search for faster rubiscos in high throughput.

The CERN Large Hadron Collider (LHC) has discovered the Higgs boson and confirmed the predictions for many of its properties given by the "Standard Model" of particle physics. However, this does not mean that particle physics is solved. Mysteries that the Standard Model does not address are still with us and, indeed, stand out more sharply than ever. To understand these mysteries, we need experiments at still higher energies. In this colloquium, I will argue that we should be planning for a particle collider reaching energies of about 10 times those of the LHC in the collisions of elementary particles. Today, there is no technology that can produce such energies robustly and at a reasonable cost. However, many solutions are under study, including colliders for protons, muons, electrons, and photons. I will review the status of these approaches to the design of the next great energy-frontier accelerator.

Terrestrial sequestration of carbon has mitigated ≈30% of
anthropogenic carbon emissions. However its distribution across
different pools—live or dead biomass, and soil and sedimentary
organic carbon— which has important implications for future
climate change mitigation, remains uncertain. By analyzing
global observational datasets of changes in terrestrial carbon
pools, we are able to partition carbon that has been sequestered
on land between 1992-2019 into live biomass and non-living
organic carbon pools. We compare our observation-based
estimates against predictions of global vegetation models and
identify key processes that are not included in most models
that can help align the models with observations. We find that
most terrestrial carbon gains are sequestered as non-living
organic matter, and thus more persistent than previously
appreciated, with a substantial fraction linked to human
activities such as river damming, wood harvest, and garbage
disposal in landfills.