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1. On Neutral Unsaturated Ouroboric Borylenes

   https://doi.org/10.1021/acs.jpca.2c04249  

   Donald, Kelling J.; Gaillard, Ulrick R.; Walker, Noah (August 2022, The Journal of Physical Chemistry A)
2. How cholesterol stiffens unsaturated lipid membranes

   https://doi.org/10.1073/pnas.2004807117  

   Chakraborty, Saptarshi; Doktorova, Milka; Molugu, Trivikram R.; Heberle, Frederick A.; Scott, Haden L.; Dzikovski, Boris; Nagao, Michihiro; Stingaciu, Laura-Roxana; Standaert, Robert F.; Barrera, Francisco N.; et al (August 2020, Proceedings of the National Academy of Sciences)

   Cholesterol is an integral component of eukaryotic cell membranes and a key molecule in controlling membrane fluidity, organization, and other physicochemical parameters. It also plays a regulatory function in antibiotic drug resistance and the immune response of cells against viruses, by stabilizing the membrane against structural damage. While it is well understood that, structurally, cholesterol exhibits a densification effect on fluid lipid membranes, its effects on membrane bending rigidity are assumed to be nonuniversal; i.e., cholesterol stiffens saturated lipid membranes, but has no stiffening effect on membranes populated by unsaturated lipids, such as 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC). This observation presents a clear challenge to structure–property relationships and to our understanding of cholesterol-mediated biological functions. Here, using a comprehensive approach—combining neutron spin-echo (NSE) spectroscopy, solid-state deuterium NMR (²H NMR) spectroscopy, and molecular dynamics (MD) simulations—we report that cholesterol locally increases the bending rigidity of DOPC membranes, similar to saturated membranes, by increasing the bilayer’s packing density. All three techniques, inherently sensitive to mesoscale bending fluctuations, show up to a threefold increase in effective bending rigidity with increasing cholesterol content approaching a mole fraction of 50%. Our observations are in good agreement with the known effects of cholesterol on the area-compressibility modulus and membrane structure, reaffirming membrane structure–property relationships. The current findings point to a scale-dependent manifestation of membrane properties, highlighting the need to reassess cholesterol’s role in controlling membrane bending rigidity over mesoscopic length and time scales of important biological functions, such as viral budding and lipid–protein interactions. 

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3. Poisson’s Ratio Characteristic Curve of Unsaturated Soils

   https://doi.org/10.1061/(ASCE)GT.1943-5606.0002424  

   Kumar Thota, Sannith; Duc Cao, Toan; Vahedifard, Farshid (January 2021, Journal of Geotechnical and Geoenvironmental Engineering)

   null (Ed.)
4. Unsaturated thermal consolidation around a heat source

   https://doi.org/10.1016/j.compgeo.2021.104091  

   Cherati, Davood Yazdani; Ghasemi-Fare, Omid (June 2021, Computers and Geotechnics)

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5. Global existence of weak solutions to unsaturated poroelasticity

   https://doi.org/10.1051/m2an/2021063  

   Both, Jakub Wiktor; Pop, Iuliu Sorin; Yotov, Ivan (November 2021, ESAIM: Mathematical Modelling and Numerical Analysis)

   We study unsaturated poroelasticity, i.e. , coupled hydro-mechanical processes in variably saturated porous media, here modeled by a non-linear extension of Biot’s well-known quasi-static consolidation model. The coupled elliptic-parabolic system of partial differential equations is a simplified version of the general model for multi-phase flow in deformable porous media, obtained under similar assumptions as usually considered for Richards’ equation. In this work, existence of weak solutions is established in several steps involving a numerical approximation of the problem using a physically-motivated regularization and a finite element/finite volume discretization. Eventually, solvability of the original problem is proved by a combination of the Rothe and Galerkin methods, and further compactness arguments. This approach in particular provides the convergence of the numerical discretization to a regularized model for unsaturated poroelasticity. The final existence result holds under non-degeneracy conditions and natural continuity properties for the constitutive relations. The assumptions are demonstrated to be reasonable in view of geotechnical applications. 

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