Analysis of isotopic signals in the Danube River water at Tulln,Austria, based on daily grab samples in 2012

Results of stable isotope measurements (δ²H, δ¹⁸O) of daily grab samples, taken from the Danube River at Tulln (river km 1963) during 2012, show seasonal and short-term variations depending on the climatic/hydrological conditions and changes in the catchment area (temperature changes, heavy rains and snow melt processes). Isotope ratios in river water clearly reflect the isotopic composition of precipitation water in the catchment area since evaporation influences play a minor role. Average δ²H and δ¹⁸O values in 2012 are?78‰ and?11.0‰, respectively, deuterium excess averages 10‰. The entire variation amounts to 1.8‰ in δ¹⁸O and 15‰ in δ²H. Quick changes of the isotopic composition within a few days emphasise the necessity of daily sampling for the investigation of hydrological events, while monthly grab sampling seems sufficient for the investigation of long-term hydro-climatic trends. ³H results show peaks (half-width 1–2 days, up to about 150 TU) exceeding the regional environmental level of about 9 TU, probably due to releases from nuclear power plants.     

Investigation of short‐range structural order in Zr69.5Cu12Ni11Al7.5 and Zr41.5Ti41.5Ni17 glasses,using X‐ray absorption spectroscopy and ab initio molecular dynamics simulations

Short‐range order has been investigated in Zr_69.5Cu₁₂Ni₁₁Al_7.5 and Zr_41.5Ti_41.5Ni₁₇ metallic glasses using X‐ray absorption spectroscopy and ab initio molecular dynamics simulations. While both of these alloys are good glass formers, there is a difference in their glass‐forming abilities (Zr_41.5Ti_41.5Ni₁₇ > Zr_69.5Cu₁₂Ni₁₁Al_7.5). This difference is explained by inciting the relative importance of strong chemical order, icosahedral content, cluster symmetry and configuration diversity.     

Switchable magnetic bottles and field gradients for particle traps

Versatile methods for the manipulation of individual quantum systems, such as confined particles, have become central elements in current developments in precision spectroscopy, frequency standards, quantum information processing, quantum simulation, and alike. For atomic and some subatomic particles, both neutral and charged, a precise control of magnetic fields is essential. In this paper, we discuss possibilities for the creation of specific magnetic field configurations which find application in these areas. In particular, we pursue the idea of a magnetic bottle which can be switched on and off by transition between the normal and the superconducting phase of a suitable material in cryogenic environments, for example, in trap experiments in moderate magnetic fields. Methods for a fine-tuning of the magnetic field and its linear and quadratic components in a trap are presented together with possible applications.     

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.     

Horizontal Redistribution of Two Fluid Phases in a Porous Medium: Experimental Investigations

Classical models for flow and transport processes in porous media employ the so-called extended Darcy’s Law. Originally, it was proposed empirically for one-dimensional isothermal flow of an incompressible fluid in a rigid, homogeneous, and isotropic porous medium. Nowadays, the extended Darcy’s Law is used for highly complex situations like non-isothermal, multi-phase and multi-component flow and transport, without introducing any additional driving forces. In this work, an alternative approach by Hassanizadeh and Gray identifying additional driving forces were tested in an experimental setup for horizontal redistribution of two fluid phases with an initial saturation discontinuity. Analytical and numerical solutions based on traditional models predict that the saturation discontinuity will persist, but a uniform saturation distribution will be established in each subdomain after an infinite amount of time. The pressure field, however, is predicted to be continuous throughout the domain at all times and is expected to become uniform when there is no flow. In our experiments, we also find that the saturation discontinuity persists. But, gradients in both saturation and pressure remain in both subdomains even when the flow of fluids stops. This indicates that the identified additional driving forces present in the truly extended Darcy’s Law are potentially significant.     

Novel carotenoids genetically engineered in a heterologous host

Carotenoids are commercially important pigments that are essential for human health. Diverse carotenoids have been identified, but availability has impeded evaluation of their pharmaceutical potential. Molecular techniques have been developed to produce specific and novel carotenoids with improved biological activities.     

Small angle neutron scattering study of sodium dodecyl sulfate micellar growth driven by addition of a hydrotropic salt

The structures of aggregates formed in aqueous solutions of an anionic surfactant, sodium dodecyl sulfate (SDS), with the addition of a cationic hydrotropic salt, p-toluidine hydrochloride (PTHC), have been investigated by small angle neutron scattering (SANS). The SANS spectra exhibit a pronounced peak at low salt concentration, indicating the presence of repulsive intermicellar interactions. Model-independent real space information about the structure is obtained from a generalized indirect Fourier transformation (GIFT) technique in combination with a suitable model for the interparticle structure factor. The interparticle interaction is captured using the rescaled mean spherical approximation (RMSA) closure relation and a Yukawa form of the interaction potential. Further quantification of the geometrical parameters of the micelles was achieved by a complete fit of the SANS data using a prolate ellipsoidal form factor and the RMSA structure factor. The present study shows that PTHC induces a decrease in the fractional charge of the micelles due to adsorption at the micellar surface and consequent growth of the SDS micelles from nearly globular to rodlike as the concentration of PTHC increases.     

Isolation, biological activity evaluation, structure elucidation, and total synthesis of eliamid: a novel complex i inhibitor

Eliamid is a secondary metabolite isolated from two bacterial strains. This molecule features a linear polyketide backbone terminated by a tetramic acid amide moiety. Among other biological activities, eliamid shows a high and specific cytostatic action on human lymphoma and cervix carcinoma cell lines. The 2,4-anti relative configuration of the C-2,C-4-dimethyl substituted amide fragment was assigned by means of Breit's rule. The absolute configuration of all stereocenters was determined by a combination of degradation methods, structural similarity analysis and total synthesis. The stereogenic centers were introduced by vinylogous Mukaiyama aldol reaction and two consecutive Myers alkylations. The use of pentafluorophenyl ester as acylation agent allowed the efficient formation of tetramic acid amide. The longest linear sequence in the synthesis consist of 13?steps and proceeds with 12?% overall yield. Differential spectroscopy experiments with beef heart submitochondrial particles established that eliamid is a potent inhibitor of the NADH-ubiquinone oxidoreductase complex. Additionally, biosynthesis of eliamid was investigated by feeding experiments with (13) C-labeled precursors.     

Atroposelective Heck Macrocyclization: Enantioselective Synthesis of Bis(bibenzylic) Natural Products

The Heck protocol was applied for the first time to the atroposelective synthesis of macrocyclic natural products. As ring closure to bis(bibenzyls) of the isoplagiochin type leads to a configurationally stable biaryl axis in the molecule, cyclization could be conducted atroposelectively in the presence of a chiral BINAP ligand.     

Organocatalytic, asymmetric synthesis of 3-sulfenylated N-boc-protected oxindoles

Sulfenylated oxindoles: The first asymmetric sulfenylation of N-Boc-protected oxindoles has been developed to provide products containing a tetrasubstituted stereogenic center in high to excellent yields (86-98?%) and, in most cases, excellent enantioselectivities (up to 96?%?ee; see scheme).