Nucleic acids promote amyloid formation in diseases including Alzheimer's and Creutzfeldt-Jakob disease. However, it remains unclear whether the close interactions between amyloid and nucleic acid allow nucleic acid secondary structure to play a role in modulating amyloid structure and function. Here we have used a simplified system of short basic peptides with alternating hydrophobic and hydrophilic amino acid residues to study nucleic acid - amyloid interactions. Employing biophysical techniques including X-ray fibre diffraction, circular dichroism spectroscopy and electron microscopy we show that the polymerized charges of nucleic acids concentrate and enhance the formation of amyloid from short basic peptides, many of which would not otherwise form fibres. In turn, the amyloid component binds nucleic acids and promotes their hybridisation at concentrations below their solution K d, as shown by time-resolved FRET studies. The self-reinforcing interactions between peptides and nucleic acids lead to the formation of amyloid nucleic acid (ANA) fibres whose properties are distinct from their component polymers. In addition to their importance in disease and potential in engineering, ANA fibres formed from prebiotically-produced peptides and nucleic acids may have played a role in early evolution, constituting the first entities subject to Darwinian evolution.

A force field to induce isomerisation of photoswitchable azobenzene groups embedded in molecular materials has been developed in the framework of force field molecular dynamics simulations. A molecular mechanics switching potential has been tuned so as to reproduce both the correct photoisomerisation timescale and mechanism that has been generated by reference nonadiabatic ab initio molecular dynamics. As a first application, we present a force field molecular dynamics study of a prototype photoswitchable foldamer in acetonitrile as solvent. Our analyses reveal that the photoisomerisation of the azobenzene unit embedded in the foldamer occurs via the so-called NN-twist mechanism, and that there exist several distinct unfolding channels for the helix that could be exploited in novel applications of photoresponsive materials.

A series of sterically and electronically fine-tuned, chelating diphosphine ligands were synthesized. The ligands are analogues of Triptyphos (TTP, 1), all based upon a variably 9,10-two-carbon-bridged 9,10-dihydroanthracene scaffold. These new TTP-type ligands were employed in the Ni(0)catalyzed isomerization of 2-methyl-3-butenenitrile (2M3BN), one of the key steps of industrial adiponitrile production by the DuPont process. The reaction showed a surprising preference for ligands bearing electron-donating substituents, such as methoxy or methyl groups, in the phenyl para position of the Ni-ligating PPh 2 units. Octyltriptyphos (3) afforded the highest 2M3BN-isomerization turnover rate yet reported. A series of deuterium-labeling experiments was performed to investigate the possibility of an isomerization mechanism consisting of a cascade of de-and rehydrocyanation steps, which could be excluded. Using the ethano-bridged ligand 4, complex 16a (4-κP:κP 0 )Ni(η 3 -C 4 H 7 )CN (supposedly an intermediate of the 2M3BN-isomerization reaction) was isolated, and its solid-state structure was determined by X-ray diffraction analysis. The complete catalytic cycle of 2M3BN isomerization with ligand 4, as suggested by the available experimental evidence, was modeled using DFT methods.

Objectives The aim of this preclinical study was to analyze and compare different grafting techniques with respect to volume stability after wound closure. Materials and Methods Four different grafting techniques were evaluated in vitro for volume stability in a one‐wall horizontal defect configuration. Group 1: guided bone regeneration (GBR) with collagen membrane, particulated xenograft; group 2: GBR with collagen membrane, particulated xenograft, pins; group 3: GBR with titanium‐reinforced membrane, particulated xenograft, pins; group 4: autogenous block graft, particulated xenograft, collagen membrane. Cone beam computed tomography scans were performed before and after wound closure, and the horizontal bone dimensions were analyzed for stability at 0‐5 mm apical to the implant shoulder (H0‐H5). Results At H0‐H2, wound closure induced a statistically significant change in bone dimensions in groups 1 and 2. In group 3, only the change in H0 was significant, and for group 4, only H2 was significant. Conclusion Wound closure has a significant impact on graft stability in a one‐wall horizontal defect configuration. GBR with additional membrane fixation showed better results than without. Titanium‐reinforced membranes and autogenous blocks showed significantly greater volume stability than GBR with collagen membrane, especially in the coronal portion.