Short-Term Therapeutic Trial of Proton Pump Inhibitors in Suspected Extraesophageal Reflux

Pharyngoesophageal gastric acid reflux is thought to initiate chronic posterior laryngitis. The gold standard for measuring gastric reflux is dual-channel 24-hour pH monitoring. This is a time-consuming, inconvenient, expensive method that is not available in all areas. New therapeutic regimes that make use of proton pump inhibitors (PPIs) have proven to be therapeutically efficient for control of acid reflux. Twenty-four consecutive patients with chronic voice disorders and signs of posterior laryngitis were selected for therapy. Twenty-four hour pH monitoring was performed independently before the therapy. The trial therapy consisted of all patients receiving pantoprazole, 40 mg once daily for 6 weeks. Immediately following the therapy a statistically significant (p < 0.05) improvement was observed in all patients. This improvement was analyzed retrospectively by comparison with the results of 24-hour pH monitoring. In 71% of the patients the 24-hour pH-monitoring gave a positive result showing a high number of patients with extraesophageal reflux in our study group. Patients with positive results of pH-monitoring responded in a statistically significant manner (p < 0.05) to the pantoprazole therapy, whereas those patients without detected reflux did not. A 3-month follow-up of the patients with a positive result of the pH-monitoring confirmed the improvement. No patients reported adverse effects. A 6-week treatment with pantoprazole can be clinically justified. It helps to save time and reduce costs, allows for selection of reflux-negative patients for alternative therapy, and may prevent inadequate treatment of patients with false-negative pH monitoring. Twenty-four hour pH monitoring is still recommended for patients unresponsive to this trial therapy.     

Reduction of flow- and eddy-currents-induced image artifacts in coronary magnetic resonance angiography using a linear centric-encoding SSFP sequence

Coronary magnetic resonance angiography (MRA) acquired using steady-state free precession (SSFP) sequences tends to suffer from image artifacts caused by local magnetic field inhomogeneities. Flow- and gradient-switching-induced eddy currents are important sources of such phase errors, especially under off-resonant conditions. In this study, we propose to reduce these image artifacts by using a linear centric-encoding (LCE) scheme in the phase-encoding (PE) direction. Abrupt change in gradients, including magnitude and polarity between consecutive radiofrequency cycles, is minimized using the LCE scheme. Results from numeric simulations and phantom studies demonstrated that signal oscillation can be markedly reduced using LCE as compared to conventional alternating centric-encoding (ACE) scheme. The image quality of coronary arteries was improved at both 1.5 and 3.0 T using LCE compared to those acquired using ACE PE scheme (1.5 T: ACE/LCE=2.2+/-0.8/3.0+/-0.6, P=.02; 3.0 T: ACE/LCE=2.1+/-1.1/3.0+/-0.8, P=.01). In conclusion, flow- and eddy-currents-induced imaging artifacts in coronary MRA using SSFP sequence can be markedly reduced with LCE acquisition of PE lines.     

Theoretical study of new acceptor and donor molecules based on polycyclic aromatic hydrocarbons

Functionalized polycyclic aromatic hydrocarbons (PAHs) are an interesting class of molecules in which the electronic state of the graphene-like hydrocarbon part is tuned by the functional group. Searching for new types of donor and acceptor molecules, a set of new PAHs has recently been investigated experimentally using ultraviolet photoelectron spectroscopy (UPS). In this work, the electronic structure of the PAHs is studied theoretically with the help of B3LYP hybrid density functionals. Using the ΔSCF method, electron binding energies have been determined which affirm, specify and complement the UPS data. Symmetry properties of molecular orbitals are analyzed for a categorization and an estimate of the related signal strength. While σ-like orbitals are difficult to detect in UPS spectra of condensed film, calculation provides a detailed insight into the hidden parts of the electronic structure of donor and acceptor molecules. In addition, a diffuse basis set (6-311++G**) was used to calculate electron affinity and LUMO eigenvalues. The calculated electron affinity (EA) provides a classification of the donor/acceptor properties of the studied molecules. Coronene-hexaone shows a high EA, comparable to TCNQ, which is a well-known classical acceptor. Calculated HOMO-LUMO gaps using the related eigenvalues have a good agreement with the experimental lowest excitation energies. TD-DFT also accurately predicts the measured optical gap.     

Inverse relation between photocurrent and absorption layer thickness in polymer solar cells

Organic solar cells based on polymer–fullerene bulk heterojunctions were optimised with respect to the short circuit photocurrent by means of optical modelling. Due to interference effects present in the thin film multilayer device, an inverse relation between active layer thickness and photocurrent was predicted and experimentally verified. Optimised photovoltaic devices yield power conversion efficiencies of 4%. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Gravitational lensing and rotation curve

Based on the geodesic equation in a static spherically symmetric metric we discuss the rotation curve and gravitational lensing. The rotation curve determines one function in the metric without assuming Einstein’s equations. Then lensing is considered in the weak field approximation of general relativity. From the null geodesics we derive the lensing equation. The gravitational potential U(r) which determines the lensing is directly give by the rotation curve U(r) = −v ²(r). This allows to test general relativity on the scale of galaxies where dark matter is relevant.     

On the stability of Archimedean tilings formed by patchy particles

We have investigated the possibility of decorating, using a bottom-up strategy, patchy particles in such a way that they self-assemble in (two-dimensional) Archimedean tilings. Except for the trihexagonal tiling, we have identified conditions under which this is indeed possible. The more compact tilings, i.e., the elongated triangular and the snub square tilings (which are built up by triangles and squares only) are found to be stable up to intermediate pressure values in the vertex representation, i.e., where the tiling is decorated with particles at its vertices. The other tilings, which are built up by rather large hexagons, octagons and dodecagons, are stable over a relatively large pressure range in the centre representation where the particles occupy the centres of the polygonal units.     

The influence of rotational coupling on K-vacancy formation in U-Pb collisions

The beta endpoint energies of the alkaline fission products^88–94Rb and^139–144Cs have been measured with an intrinsic Ge-detector at the OSTIS fission product separator. The linearity and high resolution of the detector yields an accuracy of up to a few keV. Additional beta gamma coincidence spectra allow the deduction of Q_β-values.     

The impact parameter dependence of the Pb + Pb K − MO spectrum

Molecular orbital X-rays are emitted during ion-atom collisions. The theoretical treatment, numerical results for the Pb + Pb system and a comparison with background radiation like NNB, SEB and γ-decay of Coulomb excited nuclei are presented.     

Existence of stationary,collisionless plasmas in bounded domains

We consider a collisionless plasma, which consists of electrons and positively charged ions and is confined to a bounded domain in ?³. The distribution functions of the particles are assumed to satisfy specular reflections on the boundary of the domain and the boundary is assumed to be perfectly conducting. We establish the existence of stationary plasmas in the non-relativistic, electrostatic case described by the Vlasov–Poisson system as well as in the relativistic, electrodynamic case described by the relativistic Vlasov–Maxwell system.