Symmetry/Asymmetry of the NHN Hydrogen Bond in Protonated 1,8-Bis(dimethylamino)naphthalene

Experimental and theoretical results are presented based on vibrational spectra and motional dynamics of 1,8-bis(dimethylamino)naphthalene (DMAN) and its protonated forms (DMANH+ and the DMANH+ HSO4− complex). The studies of these compounds have been performed in the gas phase and solid-state. Spectroscopic investigations were carried out by infrared spectroscopy (IR), Raman, and incoherent inelastic neutron scattering (IINS) experimental methods. Density functional theory (DFT) and Car–Parrinello molecular dynamics (CPMD) methods were applied to support our experimental findings. The fundamental investigations of hydrogen bridge vibrations were accomplished on the basis of isotopic substitutions (NH → ND). Special attention was paid to the bridged proton dynamics in the DMANH+ complex, which was found to be affected by interactions with the HSO4− anion.

Motional dynamics of single Patched1 molecules in cilia are controlled by Hedgehog and cholesterol

The Hedgehog-signaling pathway is an important target in cancer research and regenerative medicine; yet, on the cellular level, many steps are still poorly understood. Extensive studies of the bulk behavior of the key proteins in the pathway established that during signal transduction they dynamically localize in primary cilia, antenna-like solitary organelles present on most cells. The secreted Hedgehog ligand Sonic Hedgehog (SHH) binds to its receptor Patched1 (PTCH1) in primary cilia, causing its inactivation and delocalization from cilia. At the same time, the transmembrane protein Smoothened (SMO) is released of its inhibition by PTCH1 and accumulates in cilia. We used advanced, single molecule-based microscopy to investigate these processes in live cells. As previously observed for SMO, PTCH1 molecules in cilia predominantly move by diffusion and less frequently by directional transport, and spend a fraction of time confined. After treatment with SHH we observed two major changes in the motional dynamics of PTCH1 in cilia. First, PTCH1 molecules spend more time as confined, and less time freely diffusing. This result could be mimicked by a depletion of cholesterol from cells. Second, after treatment with SHH, but not after cholesterol depletion, the molecules that remain in the diffusive state showed a significant increase in the diffusion coefficient. Therefore, PTCH1 inactivation by SHH changes the diffusive motion of PTCH1, possibly by modifying the membrane microenvironment in which PTCH1 resides.

Confinement effects of a crystalline sponge on ferrocene and ferrocene carboxaldehyde

The confinement effects of a crystalline sponge on organometallic sandwich compounds are investigated, in which a network of weak non-covalent interactions effectively dictate guest inclusion behaviour and motional dynamics.

An Unstable Equilibrium and Process of Becoming in All This Can Happen

<em>All This Can Happen</em> is explored as an “unstable equilibrium” with one essential raison d’être: movement. The term “unstable equilibrium” is taken from Maya Deren, as she relates it to her own films as being in a constant process of ritualistic becomingness. The alternation of images—the cinematographic choreography—is what makes <em>All This Can Happen</em> a film that enables us to discover movement in its purest forms and actions, especially because things are made to move. It is the “unstable equilibrium” of these pictures and their in-between, a balance of different visual and motional dynamics, that develops into an understanding and becoming of movement.