Creating ground state molecules with optical feshbach resonances in tight traps

We propose to create ultracold ground state molecules in an atomic Bose-Einstein condensate by adiabatic crossing of an optical Feshbach resonance. We envision a scheme where the laser intensity and possibly also frequency are linearly ramped over the resonance. Our calculations for (87)Rb show that for sufficiently tight traps it is possible to avoid spontaneous emission while retaining adiabaticity, and conversion efficiencies of up to 50% can be expected.     

Uptake of magnetic nanoparticles into cells for cell tracking

A challenge for future applications in nanotechnology is the functional integration of nano-sized materials into cellular structures. Here we investigated superparamagnetic Fe₃O₄ iron oxide nanoparticles coated with a lipid bilayer for uptake into cells and for targeting subcellular compartments. It was found that magnetic nanoparticles (MNPs) are effectively taken up into cells and make cells acquire magnetic activity. Biotin-conjugated MNPs were further functionalized by binding of the fluorescent tag streptavidin–fluorescein isothiocyanate (FITC) and, following uptake into cells, shown to confer magnetic activity and fluorescence labeling. Such FITC-MNPs were localized in the lysosomal compartment of cells which suggests a receptor-mediated uptake mechanism.     

The titration of clay minerals II. Structure-based model and implications for clay reactivity

The potentiometric titration and CEC data presented in part I are modeled in this paper, part II. Two models are compared: the two pK, three complexation sites plus exchange sites nonelectrostatic model developed by Baeyens and Bradbury and a model based on the MUSIC approach developed by Hiemstra and Van Riemsdijk. Both morphological and structural information is used to develop this new model. Morphological information is taken from the literature, while structural information is taken from the literature and constrained by supporting FTIR experiments. The Baeyens and Bradbury model is found to reproduce the general tendency of the titration curve, whereas the model based on the Hiemstra and Van Riemsdijk MUSIC approach provides a better fit to the experimental data. The former uses only 3 edge reaction sites, whereas the latter uses at least 27 edge reaction sites. Five main reactive sites are sufficient to fit the MUSIC model curve, but the model allows us to derive the properties of 22 other reactive sites. Logically, the greater the number of sites, the better the fit. Nevertheless, fewer adjustable parameters are necessary for the Hiemstra and Van Riemsdijk MUSIC model than for the Baeyens and Bradbury model, thanks to structural and morphological constraints. The precision of the potentiometric titration curve is insufficient to verify that the properties of the 27 sites given by the MUSIC model are effective. Thus, we coupled some properties of clay minerals, such as dissolution, to the modeled acid-base properties of these sites to assess our model. We then questioned the ability of simplified models such as the Baeyens and Bradbury model to predict the interactions between clay minerals and solutions in natural environments. In addition, we derived the cation exchange selectivity coefficients for CaCl+ ionic pairs and H+ from our CEC data and gave an estimate for the CaOH+ selectivity coefficient.     

High yielding microwave-assisted synthesis of tri-substituted 1,3,5-triazines using Pd-catalyzed aryl and heteroarylamination

A rapid and efficient Pd-catalyzed aryl and heteroarylamination under microwave irradiation has been developed for various tri-substituted triazines that can serve as versatile building blocks for both supramolecular and medicinal chemistry research. Particularly valuable features of this method included the short reaction time, good yield, and convenient operation.     

Element determination in medieval soil samples by total reflection X-ray fluorescence analysis

An aqua regia extraction procedure for heavy metals in soils optimised for total reflection X-ray fluorescence analysis is presented. The procedure is applied to 92 soil samples of medieval layers from the city area of Dortmund. Sixteen elements (P, S, K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Rb, Sr, Ag, Sn, and Pb) were used to characterise 17 sample sites. The results are projected onto the medieval urban structure of Dortmund. Two sites loaded with non-ferrous heavy metal could be detected and correlated with archaeological data. The efficiency and repeatability of the proposed extraction procedure is discussed.     

Structure and conformations of N-(fluoroformyl)imidosulfurous dichloride,FC(O)N=SCl2

The IR (gas) and Raman (liquid) spectra of FC(O)NSCl(2) demonstrate the presence of a conformational mixture in both phases. According to a gas electron diffraction study, the main conformer (94(8)%) possesses a syn-syn structure (C(O)F group synperiplanar with respect to the SCl(2) bisector and the C=O bond synperiplanar to the N=S bond). Quantum chemical calculations (HF, B3LYP and MP2 with 6-31G basis set, and MP2/6-311(2df)) predict a syn-anti structure for the second conformer. Analysis of the IR (gas) spectrum results in a contribution of 5(1)% of the minor form, corresponding to a Gibbs free energy difference DeltaG degrees = G degrees (syn-anti) - G degrees (syn-syn) = 1.75(15) kcal/mol. This value is reproduced very well by quantum chemical calculations, which include electron correlation effects (DeltaG degrees = 1.28-1.56 kcal/mol). The HF approximation overestimates this energy difference (DeltaG degrees = 3.24 kcal/mol).     

Electronic spectra of uranyl chloride complexes in acetone: a CASSCF/CASPT2 investigation

A theoretical study is presented of the electronic spectra of the complexes UO(2)Cl(2)ac(4), UO(2)Cl(2)ac(3), [UO(2)Cl(3)ac(2)](-) and [UO(2)Cl(3)ac](-) (ac = acetone) using perturbation theory based on a complete-active-space type wavefunction (CASSCF/CASPT2). Both scalar relativistic effects and spin-orbit coupling were included in the calculations. The calculated excitation energies and oscillator strength values have been compared to the experimental absorption spectrum for uranyl chloride complexes in acetone solution, for chloride-to-uranyl ratios between two and three. The main purpose of this work was to investigate the origin of the remarkable intensity increase observed in the lower part of the experimental absorption spectra, upon addition of chloride to uranyl complexes in acetone. The calculated excitation energies for the different complexes are similar and closely correspond to the experimental data. However, in none of the theoretical spectra, the high intensities observed in the lower part of the experimental spectrum are reproduced.     

Weak chemiluminescence emission during base induced rearrangement of G-factors

A rearrangement in basic medium of the natural endoperoxide G3-factor extracted from Eucalyptus grandis is described. Evidence to support a 1,2-dioxetane intermediate that decomposes with weak luminescence emission (quantum yield) is presented.