Post-implant transcatheter aortic prosthesis deformation: tricuspid versus bicuspid valve.

Objective: We sought to assess whether post-implant transcatheter aortic valve prosthesis multi detector computed characteristics differ between patients with native tricuspid and bicuspid aortic valve stenosis, as well as the effect on valve performance and clinical implications.

Methods: We analysed 100 consecutive post-implant multi detector computed tomography scans to assess self-expandable prosthesis non-uniform expansion at six pre-specified valvular levels, and other specific parameters, including valvular and perivalvular thrombosis at six months follow-up. Echocardiographic prosthesis performance and clinical outcome was also evaluated.

Perspectives on weak interactions in complex materials at different length scales.

Nanocomposite materials consist of nanometer-sized quantum objects such as atoms, molecules, voids or nanoparticles embedded in a host material. These quantum objects can be exploited as a super-structure, which can be designed to create material properties targeted for specific applications. For electromagnetism, such targeted properties include field enhancements around the bandgap of a semiconductor used for solar cells, directional decay in topological insulators, high kinetic inductance in superconducting circuits, and many more.

Purcell-induced suppression of superradiance for molecular overlayers on noble atom surfaces.

We study the impact of an environment on the electromagnetic responses of a molecule in the presence of a dielectric medium. By applying the dipole-dipole coupling between the molecule's and the environment's degrees of freedom, we can reduce the complex system into its components and predict excitation lifetimes of single and few molecules attached to a dielectric surface by knowing the entire quantum-mechanical properties of the molecules, such as transition energies and dipole moments. The derived theory allows for the description of superradiance between two molecules depending on the geometric arrangement between both concerning their separation and orientation with respect to each other.

Improved proton-transfer barriers with van der Waals density functionals: Role of repulsive non-local correlation.

Proton-transfer (PT) between organic complexes is a common and important biochemical process. Unfortunately, PT energy barriers are difficult to accurately predict using density functional theory (DFT); in particular, using the generalized gradient approximation (GGA) tends to underestimate PT barriers. Moreover, PT typically occurs in environments where dispersion forces contribute to the cohesion of the system; thus, a suitable exchange-correlation functional should accurately describe both dispersion forces and PT barriers.

Next-Generation Nonlocal van der Waals Density Functional.

The fundamental ideas for a nonlocal density functional theory-capable of reliably capturing van der Waals interactions-were already conceived in the 1990s. In 2004, a seminal paper introduced the first practical nonlocal exchange-correlation functional called vdW-DF, which has become widely successful and laid the foundation for much further research. However, since then, the functional form of vdW-DF has remained unchanged.

Chemical stability of CaCo O /CaMnO p-n junction for oxide-based thermoelectric generators.

An all-oxide thermoelectric generator for high-temperature operation depends on a low electrical resistance of the direct p-n junction. CaCo O and CaMnO exhibit p-type and n-type electronic conductivity, respectively, and the interface between these compounds is the material system investigated here. The effect of heat treatment (at 900 °C for 10 h in air) on the phase and element distribution within this p-n junction was characterized using advanced transmission electron microscopy combined with X-ray diffraction.

The role of grain boundary scattering in reducing the thermal conductivity of polycrystalline XNiSn (X = Hf, Zr, Ti) half-Heusler alloys.

Thermoelectric application of half-Heusler compounds suffers from their fairly high thermal conductivities. Insight into how effective various scattering mechanisms are in reducing the thermal conductivity of fabricated XNiSn compounds (X = Hf, Zr, Ti, and mixtures thereof) is therefore crucial. Here, we show that such insight can be obtained through a concerted theory-experiment comparison of how the lattice thermal conductivity κ (T) depends on temperature and crystallite size.

Catalytic diversity in self-propagating peptide assemblies.

The protein-only infectious agents known as prions exist within cellular matrices as populations of assembled polypeptide phases ranging from particles to amyloid fibres. These phases appear to undergo Darwinian-like selection and propagation, yet remarkably little is known about their accessible chemical and biological functions. Here we construct simple peptides that assemble into well-defined amyloid phases and define paracrystalline surfaces able to catalyse specific enantioselective chemical reactions.

Assessment of two hybrid van der Waals density functionals for covalent and non-covalent binding of molecules.

Two hybrid van der Waals density functionals (vdW-DFs) are developed using 25% Fock exchange with (i) the consistent-exchange vdW-DF-cx functional [K. Berland and P. Hyldgaard, Phys.

Spin Signature of Nonlocal Correlation Binding in Metal-Organic Frameworks.

We develop a proper nonempirical spin-density formalism for the van der Waals density functional (vdW-DF) method. We show that this generalization, termed svdW-DF, is firmly rooted in the single-particle nature of exchange and we test it on a range of spin systems. We investigate in detail the role of spin in the nonlocal correlation driven adsorption of H_{2} and CO_{2} in the linear magnets Mn-MOF74, Fe-MOF74, Co-MOF74, and Ni-MOF74.

van der Waals forces in density functional theory: a review of the vdW-DF method.

A density functional theory (DFT) that accounts for van der Waals (vdW) interactions in condensed matter, materials physics, chemistry, and biology is reviewed. The insights that led to the construction of the Rutgers-Chalmers van der Waals density functional (vdW-DF) are presented with the aim of giving a historical perspective, while also emphasizing more recent efforts which have sought to improve its accuracy. In addition to technical details, we discuss a range of recent applications that illustrate the necessity of including dispersion interactions in DFT.

Neurofibrillar tangle surrogates: histone H1 binding to patterned phosphotyrosine peptide nanotubes.

Living cells contain a range of densely phosphorylated surfaces, including phospholipid membranes, ribonucleoproteins, and nucleic acid polymers. Hyperphosphorylated surfaces also accumulate in neurodegenerative diseases as neurofibrillar tangles. We have synthesized and structurally characterized a precisely patterned phosphotyrosine surface and establish this assembly as a surrogate of the neuronal tangles by demonstrating its high-affinity binding to histone H1.

van der Waals density functionals built upon the electron-gas tradition: facing the challenge of competing interactions.

The theoretical description of sparse matter attracts much interest, in particular for those ground-state properties that can be described by density functional theory. One proposed approach, the van der Waals density functional (vdW-DF) method, rests on strong physical foundations and offers simple yet accurate and robust functionals. A very recent functional within this method called vdW-DF-cx [K.

Mapping amyloid-β(16-22) nucleation pathways using fluorescence lifetime imaging microscopy.

The cross-β peptide architecture is associated with numerous functional biomaterials and deleterious disease related aggregates. While these diverse and ubiquitous paracrystalline assemblies have been widely studied, a fundamental understanding of the nucleation and aggregation pathways to these structures remains elusive. Here we highlight a novel application of fluorescence lifetime imaging microscopy in characterising the critical stages of peptide aggregation.

τFCS: multi-method global analysis enhances resolution and sensitivity in fluorescence fluctuation measurements.

Fluorescence fluctuation methods have become invaluable research tools for characterizing the molecular-level physical and chemical properties of complex systems, such as molecular concentrations, dynamics, and the stoichiometry of molecular interactions. However, information recovery via curve fitting analysis of fluctuation data is complicated by limited resolution and challenges associated with identifying accurate fit models. We introduce a new approach to fluorescence fluctuation spectroscopy that couples multi-modal fluorescence measurements with multi-modal global curve fitting analysis.

Electronic cameras for low-light microscopy.

This chapter introduces to electronic cameras, discusses the various parameters considered for evaluating their performance, and describes some of the key features of different camera formats. The chapter also presents the basic understanding of functioning of the electronic cameras and how these properties can be exploited to optimize image quality under low-light conditions. Although there are many types of cameras available for microscopy, the most reliable type is the charge-coupled device (CCD) camera, which remains preferred for high-performance systems.

Global analysis in fluorescence correlation spectroscopy and fluorescence lifetime microscopy.

Fluorescence correlation spectroscopy (FCS) and related fluctuation spectroscopy and microscopy methods have become important research tools that enable detailed investigations of the chemical and physical properties of molecules and molecular systems in a variety of complex environments. Information recovery via curve fitting of fluctuation data can present complicating challenges due to limited resolution and/or problems with fitting model verification. We discuss a new approach to data analysis called τFCS that couples multiple modes of signal acquisition, here specifically FCS and fluorescence lifetimes, with global analysis.

Benchmarking van der Waals density functionals with experimental data: potential-energy curves for H2 molecules on Cu(111), (100) and (110) surfaces.

Detailed physisorption data from experiment for the H(2) molecule on low-index Cu surfaces challenge theory. Recently, density functional theory (DFT) has been developed to account for nonlocal correlation effects, including van der Waals (dispersion) forces. We show that the functional vdW-DF2 gives a potential-energy curve, potential-well energy levels and difference in lateral corrugation promisingly close to the results obtained by resonant elastic backscattering-diffraction experiments.

Phase networks of cross-β peptide assemblies.

Recent evidence suggests that simple peptides can access diverse amphiphilic phases, and that these structures underlie the robust and widely distributed assemblies implicated in nearly 40 protein misfolding diseases. Here we exploit a minimal nucleating core of the Aβ peptide of Alzheimer's disease to map its morphologically accessible phases that include stable intermolecular molten particles, fibers, twisted and helical ribbons, and nanotubes. Analyses with both fluorescence lifetime imaging microscopy (FLIM) and transmission electron microscopy provide evidence for liquid-liquid phase separations, similar to the coexisting dilute and dense protein-rich liquid phases so critical for the liquid-solid transition in protein crystallization.

Do two-dimensional "noble gas atoms" produce molecular honeycombs at a metal surface?

Anthraquinone self-assembles on Cu(111) into a giant honeycomb network with exactly three molecules on each side. Here we propose that the exceptional degree of order achieved in this system can be explained as a consequence of the confinement of substrate electrons in the pores, with the pore size tailored so that the confined electrons can adopt a noble-gas-like two-dimensional quasi-atom configuration with two filled shells. Formation of identical pores in a related adsorption system (at different overall periodicity due to the different molecule size) corroborates this concept.

A van der Waals density functional study of adenine on graphene: single-molecular adsorption and overlayer binding.

The adsorption of an adenine molecule on graphene is studied using a first-principles van der Waals functional, vdW-DF (Dion et al 2004 Phys. Rev. Lett.

Direct observation of nucleation and growth in amyloid self-assembly.

Access to native protein structure depends on precise polypeptide folding and assembly pathways. Identifying folding missteps that may lead to the nearly 40 protein misfolding diseases could feature prominently in the development of intervention strategies. Accordingly, we have investigated the earliest steps of assembly by the folding nucleus of the Alzheimer's disease Abeta peptide with real-time imaging and fluorescence correlation spectroscopy.

Structure and binding in crystals of cagelike molecules: hexamine and platonic hydrocarbons.

In this paper, we show that first-principle calculations using a van der Waals density functional (vdW-DF) [M. Dion, H. Rydberg, E.

Fibrillogenesis in continuously spun synthetic collagen fiber.

The universal structural role of collagen fiber networks has motivated the development of collagen gels, films, coatings, injectables, and other formulations. However, reported synthetic collagen fiber fabrication schemes have either culminated in short, discontinuous fiber segments at unsuitably low production rates, or have incompletely replicated the internal fibrillar structure that dictates fiber mechanical and biological properties. We report a continuous extrusion system with an off-line phosphate buffer incubation step for the manufacture of synthetic collagen fiber.