A solvent extraction technique for the isotopic measurement of dissolved copper in seawater

Stable copper (Cu) isotope geochemistry provides a new perspective for investigating and understanding Cu speciation and biogeochemical Cu cycling in seawater. In this work, sample preparation for isotopic analysis employed solvent-extraction with amino pyrollidine dithiocarbamate/diethyl dithiocarbamate (APDC/DDC), coupled with a nitric acid back-extraction, to concentrate Cu from seawater. This was followed by Cu-purification using anion-exchange. This straightforward technique is high yielding and fractionation free for Cu and allows precise measurement of the seawater Cu isotopic composition using multi-collector inductively coupled plasma mass-spectrometry. A deep-sea profile measured in the oligotrophic north Tasman Sea shows fractionation in the Cu isotopic signature in the photic zone but is relatively homogenised at depth. A minima in the Cu isotopic profile correlates with the chlorophyll a maximum at the site. These results indicate that a range of processes are likely to fractionate stable Cu isotopes in seawater.     

SCON—a Short Conditional intrON for conditional knockout with one-step zygote injection

The generation of conditional alleles using CRISPR technology is still challenging. Here, we introduce a Short Conditional intrON (SCON, 189 bp) that enables the rapid generation of conditional alleles via one-step zygote injection. In this study, a total of 13 SCON mouse lines were successfully generated by 2 different laboratories. SCON has conditional intronic functions in various vertebrate species, and its target insertion is as simple as CRISPR/Cas9-mediated gene tagging.Subject terms: Genetic engineering, Gene targeting, Genetic models     

Pigments with improved properties – microreaction technology as a new approach for synthesis of pigments –

Clariant, as an important pigment producer forces the investigation of new pigments with improved qualities and properties to fulfill the rising tomorrow's demands of customers. For these reasons, new production ways like microreaction technology are included. This paper focuses on results obtained in manufacturing pigments in a lab-scale microreactor as well as in a microreactor pilot plant. Investigations of the diazotation, azo-coupling and laking steps of pigments have shown not only the principle feasibility of these reactions in laboratory microreactors but also significant improvement of coloristic properties. The microreactor pilot plant, realized by the concept of numbering-up instead of conventional scaling-up process, allowed more detailed investigations of the complete azo-pigments synthesis under production conditions.     

Scaling properties of resonant electron transfer in ion—metal-surface interactions

Scaling properties of resonant electron transfer in the interaction of atoms and positive ions with metal surfaces are revealed by examining the dependence of numerically calculated transition matrix elements and (first-order) transition rates upon the scaled ion-surface distance D = D/D_n, where D_n is the classical threshold distance for electron transfer involving ionic stat principal quantum number n. For zero orbital angular momentum and fixed energy of the ionic states, the n-dependence of the rates at D = 1 is found to approach, in the large-n limit, a simple power law. A scaling law is established that connects, in the range D 1, transition rates for arbitrary (large) principal quantum numbers.     

Kommunikative Rationalität, Logik und Mathematik

Zusammenfassung. In dieser Arbeit wird folgende These erl?utert und begründet: Sinn und Bedeutung von Mathematik liegen letztlich darin, da{?} Mathematik die rationale Kommunikation von Menschen wirksam zu unterstützen vermag. Dazu werden die Begriffe der kommunikativen Rationalit?t (im Sinne von Jürgen Habermas), der kommunikativen Logik (im Sinne der Peirceschen Sp?tphilosophie) und der kommunikativen Mathematik (im Sinne Allgemeiner Wissenschaft) ausführlich expliziert. Mit diesen Begriffen wird argumentiert, da? die Mathematik über ihre enge Verbindung zur Logik kommunikative Rationalit?t aktivieren und damit die rationale Kommunikation von Menschen wirksam unterstützen kann. Eingegangen: 13. Februar 2002 / Angenommen: 16. August 2002     

Pressure and flow in two dimensional numerical bifurcation models

The finite element method has been used to solve the Navier-Strokes equations for steady flow conditions in bifurcations. The results are presented as pressure, velocity and streamline plots at different Reynolds number. The three bifurcations considered have rigid walls and bifurcation angles of 0°, 20° and 180°. For the bifurcation with branch angles 0° and 20° there is flow separation along the inner wall of the outlet branches and large spatial pressure variations, these phenomena being more pronounced at the higher Reynolds numbers. For the bifurcation with a branch angle of 180° the high pressure gradients occured at the outer corner and for the high Reynolds number a vortex formation developed downstream of this corner.     

The hole spectrum of 12C

The proton hole spectrum of ¹²C has been investigated in the framework of the continuum shell model with residual interactions. Calculated separation-energy spectra for the reaction ¹²C(p, 2p) show strong deviation from previous results which were obtained by the Green function method with a second-order mass operator.