Low-rank and sparse matrix decomposition for compressed sensing reconstruction of magnetic resonance 4D phase contrast blood flow imaging (loSDeCoS 4D-PCI).

Blood flow measurements using 4D Phase Contrast blood flow imaging (PCI) provide an excellent fully non-invasive technique to assess the hemodynamics clinically in-vivo. Iterative reconstruction techniques combined with parallel MRI have been proposed to reduce the data acquisition time, which is the biggest drawback of 4D PCI. The novel LoSDeCoS technique combines these ideas with the separation into a low-rank and a sparse component.

High-resolution 3D whole-heart coronary MRA: a study on the combination of data acquisition in multiple breath-holds and 1D residual respiratory motion compensation.

Object: To study a scan protocol for coronary magnetic resonance angiography based on multiple breath-holds featuring 1D motion compensation and to compare the resulting image quality to a navigator-gated free-breathing acquisition. Image reconstruction was performed using L1 regularized iterative SENSE.

Materials And Methods: The effects of respiratory motion on the Cartesian sampling scheme were minimized by performing data acquisition in multiple breath-holds.

Dielectric properties of water ice, the ice Ih/XI phase transition, and an assessment of density functional theory.

The dielectric properties of the hydrogen disordered hexagonal phase (Ih) of water ice have been computed using density functional theory (DFT) based Monte Carlo simulations in the isobaric-isothermal ensemble. Temperature dependent data yield a fit for the Curie-Weiss law of the system and hence a prediction of the temperature of the phase transition from the Ih phase to the hydrogen ordered ice XI phase. Direct simulations around the phase transition temperature confirm and refine the predicted phase transition temperatures and provide data for further properties, such as the linear thermal expansion coefficient.

Control of molecular organization and energy level alignment by an electronically nanopatterned boron nitride template.

Suitable templates to steer the formation of nanostructure arrays on surfaces are indispensable in nanoscience. Recently, atomically thin sp(2)-bonded layers such as graphene or boron nitride (BN) grown on metal supports have attracted considerable interest due to their potential geometric corrugation guiding the positioning of atoms, metallic clusters or molecules. Here, we demonstrate three specific functions of a geometrically smooth, but electronically corrugated, sp(2)/metal interface, namely, BN/Cu(111), qualifying it as a unique nanoscale template.

Significant substituent effect on the anomerization of pyranosides: mechanism of anomerization and synthesis of a 1,2-cis glucosamine oligomer from the 1,2-trans anomer.

Aminoglycosides containing a 2,3-trans carbamate group easily undergo anomerization from the 1,2-trans glycoside to the 1,2-cis isomer under mild acidic conditions. The N-substituent of the carbamate has a significant effect on the anomerization reaction; in particular, an N-acetyl group facilitated rapid and complete α-anomerization. The differences in reactivity due to the various N-substituents were supported by the results of DFT calculations; the orientation of the acetyl carbonyl group close to the anomeric position was found to contribute significantly to the directing of the anomerization reaction.

Impact of donor-acceptor functionalization on the properties of linearly π-conjugated oligomers: establishing quantitative relationships for the substituent and substituent cooperative effect based on quantum chemical calculations.

To understand better the impact of donor-acceptor substitution on the properties of linearly π-conjugated compounds, we performed a computational study on a series of variably substituted trans-polyacetylenes, polyynes, and polythiophenes. The focus of this work is on how rapidly the impact of a given substituent or a given combination of substituents vanishes along the π-conjugated chain. The response of the structural (bond-length alternation, rotational barrier) and molecular properties ((hyper)polarizability, chemical shift) to substitution is analyzed using different protocols, including a superposition model for the evaluation of the cooperative effect of substituents in homo- and heterosubstituted oligomers.

Simulation of Adsorption Processes at Metallic Interfaces: An Image Charge Augmented QM/MM Approach.

A novel method for including polarization effects within hybrid quantum mechanics/molecular mechanics (QM/MM) simulations of adsorbate-metal systems is presented. The interactions between adsorbate (QM) and metallic substrate (MM) are described at the MM level of theory. Induction effects are additionally accounted for by applying the image charge formulation.

[Oesophageal GIST at the left tracheobronchial angle: resection with right-sided VATS].

Objective: The vast majority of submucosal oesophageal tumours are leiomyomas. Gastrointestinal stromal tumours (GIST) account for only one percent of all gastrointestinal malignancies, whereby an oesophageal location represents a medical rarity. Although surgical resection is the gold standard, the optimal procedure remains a matter of debate.

Efficient Linear-Scaling Density Functional Theory for Molecular Systems.

Despite recent progress in linear scaling (LS) density function theory (DFT), the computational cost of the existing LS methods remains too high for a widespread adoption at present. In this work, we exploit nonorthogonal localized molecular orbitals to develop a series of LS methods for molecular systems with a low computational overhead. High efficiency of the proposed methods is achieved with a new robust two-stage variational procedure or by replacing the optimization altogether with an accurate nonself-consistent approach.

Exposure to cues associated with palatable food reward results in a dopamine D₂ receptor-dependent suppression of evoked synaptic responses in the entorhinal cortex.

Background: The lateral entorhinal cortex receives inputs from ventral tegmental area dopamine neurons that are activated by exposure to food-related cues, and exogenously applied dopamine is known to modulate excitatory synaptic responses within the entorhinal cortex.

Methods: The present study used in vivo synaptic field potential recording techniques to determine how exposure to cues associated with food reward modulates synaptic responses in the entorhinal cortex of the awake rat. Chronically implanted electrodes were used to monitor synaptic potentials in the entorhinal cortex evoked by stimulation of the piriform (olfactory) cortex, and to determine how synaptic responses are modulated by food-related cues.

Rewarding stimulation of the lateral hypothalamus induces a dopamine-dependent suppression of synaptic responses in the entorhinal cortex.

The entorhinal cortex receives inputs from sensory and associational cortices, as well as a substantial input from midbrain dopaminergic neurons. Dopamine is likely to modulate the responsiveness of entorhinal cortex neurons to sensory inputs, and excitatory synaptic responses in layers I/II of the entorhinal cortex in vitro can be either facilitated or suppressed by dopamine depending upon the concentration applied. Rewarding stimulation of the lateral hypothalamus leads to activation of dopamine neurons, and the present study evaluated the effect of rewarding stimulation on synaptic responses in the lateral entorhinal cortex evoked by stimulation of the primary olfactory (piriform) cortex in behaving rats.

Electron Correlation in the Condensed Phase from a Resolution of Identity Approach Based on the Gaussian and Plane Waves Scheme.

The second-order Møller-Plesset perturbation energy (MP2) and the Random Phase Approximation (RPA) correlation energy are increasingly popular post-Kohn-Sham correlation methods. Here, a novel algorithm based on a hybrid Gaussian and Plane Waves (GPW) approach with the resolution-of-identity (RI) approximation is developed for MP2, scaled opposite-spin MP2 (SOS-MP2), and direct-RPA (dRPA) correlation energies of finite and extended system. The key feature of the method is that the three center electron repulsion integrals (μν|P) necessary for the RI approximation are computed by direct integration between the products of Gaussian basis functions μν and the electrostatic potential arising from the RI fitting densities P.

Nonlocal van der Waals functionals: the case of rare-gas dimers and solids.

Recently, the nonlocal van der Waals (vdW) density functionals [M. Dion, H. Rydberg, E.

Design, synthesis, and initial evaluation of a high affinity positron emission tomography probe for imaging matrix metalloproteinases 2 and 9.

The activity of matrix metalloproteinases (MMPs) is elevated locally under many pathological conditions. Gelatinases MMP2 and MMP9 are of particular interest because of their implication in angiogenesis, cancer cell proliferation and metastasis, and atherosclerotic plaque rupture. The aim of this study was to identify and develop a selective gelatinase inhibitor for imaging active MMP2/MMP9 in vivo.

Structural and electronic properties of a large-scale Moiré pattern of hexagonal boron nitride on Cu(111) studied with density functional theory.

Hexagonal boron nitride (h-BN) adsorbed on metal surfaces shows great promise for applications in nanoscience. Depending on the nature of the substrate, effects such as an extended corrugation of the monolayer can be observed and utilized, e.g.

Reversible inhibition of calcium oxalate monohydrate growth by an osteopontin phosphopeptide.

Calcium oxalate, primarily as calcium oxalate monohydrate (COM), is the primary constituent of most kidney stones. Certain proteins, such as osteopontin (OPN), inhibit stone formation. The complexity of stone formation and the effects of urinary proteins at various stages of the process make it hard to predict the exact physiological roles of these proteins in growth inhibition.

Inhibition of Rac and ROCK signalling influence osteoblast adhesion, differentiation and mineralization on titanium topographies.

Reducing the time required for initial integration of bone-contacting implants with host tissues would be of great clinical significance. Changes in osteoblast adhesion formation and reorganization of the F-actin cytoskeleton in response to altered topography are known to be upstream of osteoblast differentiation, and these processes are regulated by the Rho GTPases. Rac and RhoA (through Rho Kinase (ROCK)).

Passive time-multiplexing super-resolved technique for axially moving targets.

In this paper we present a super-resolving approach for detecting an axially moving target that is based upon a time-multiplexing concept and that overcomes the diffraction limit set by the optics of an imaging camera by a priori knowledge of the high-resolution background in front of which the target is moving. As the movement trajectory is axial, the approach can be applied to targets that are approaching or moving away from the camera. By recording a set of low-resolution images at different target axial positions, the super-resolving algorithm weights each image by demultiplexing them using the high-resolution background image and provides a super-resolved image of the target.

4. Contemporary research in contact lens care.

As our understanding of the eye and how it works evolves, we must re-evaluate previous findings, beliefs, and methods of diagnosis and treatment. The eye has proven to be naturally adept at protecting itself from pathogenic intruders, but contact lens wear and lens cleaning products can adversely impact this innate ability. Keeping up to date on the latest information is challenging, and becomes more complex when trying to incorporate the new scientific data into clinical practice.

Prior-based automatic segmentation of the carotid artery lumen in TOF MRA (PASCAL).

In current clinical practice, examinations of the carotid artery bifurcation are commonly carried out with Computed Tomography Angiography (CTA) or contrast-enhanced Magnetic Resonance Angiography (ceMRA). Quantitative information about vessel morphology, extracted from segmentations, is promising for diagnosis of vessel pathologies. However, both above-mentioned techniques require the administration of contrast media.

Toward animal cell culture-based influenza vaccine design: viral hemagglutinin N-glycosylation markedly impacts immunogenicity.

The glycoproteins hemagglutinin (HA) and neuraminidase are the major determinants of host range and tissue tropism of the influenza virus. HA is the most abundant protein in the virus particle membrane and represents the basis of most influenza vaccines. It has been reported that influenza virus HA N-glycosylation markedly depends on the host cell line used for virus production.

Second-Order Møller-Plesset Perturbation Theory in the Condensed Phase: An Efficient and Massively Parallel Gaussian and Plane Waves Approach.

A novel algorithm, based on a hybrid Gaussian and plane waves (GPW) approach, is developed for the canonical second-order Møller-Plesset perturbation energy (MP2) of finite and extended systems. The key aspect of the method is that the electron repulsion integrals (ia|λσ) are computed by direct integration between the products of Gaussian basis functions λσ and the electrostatic potential arising from a given occupied-virtual pair density ia. The electrostatic potential is obtained in a plane waves basis set after solving the Poisson equation in Fourier space.

Material properties that predict preservative uptake for silicone hydrogel contact lenses.

Objectives: To assess material properties that affect preservative uptake by silicone hydrogel lenses.

Methods: We evaluated the water content (using differential scanning calorimetry), effective pore size (using probe penetration), and preservative uptake (using high-performance liquid chromatography with spectrophotometric detection) of silicone and conventional hydrogel soft contact lenses.

Results: Lenses grouped similarly based on freezable water content as they did based on total water content.