The structure of light p-shell nuclei

It is demonstrated for the first time that a number of observed low lying nuclear states in light p-shell nuclei are in fact eigenstates of a two-body hamiltonian which describes the two nucleon system. It is observed that in some heavier p-shell nuclei there appear states which may not be eigenstates of this hamiltonian.     

Synthesis of gamma-methylene oxacycles and alpha- and beta-alkylidene lactones via silicon-assisted ring opening of cyclopropyl carbinols

Cyclopropyl carbinols bearing a (tert-butyldiphenylsilyl)methyl substituent undergo silicon-assisted regioselective ring cleavage and the resulting beta-silyl carbocation is intramolecularly trapped with hydroxy and ester functions to generate gamma-methylene oxacycles and alpha- and beta-alkylidene lactones without the cleavage of the silicon function.     

Studies on the preparation of a131Ba−131Cs generator

¹³¹Cs has been a useful radionuclide for myocardial scanning and localisation of certain tumors in man. It has a half-life of 9.7 days and the decay product of¹³¹Ba (T=11.6 d). The authors have developed a¹³¹Ba−¹³¹Cs generator based on ion exchange chromatography over hydrous zirconium oxide yielding¹³¹Cs quantitatively and in a pure form. This method can also be employed in any isotope laboratory for the large scale production of¹³¹Cs.     

Identification of critical residues in loop E in the 5-HT3ASR binding site

Background  

The serotonin type 3 receptor (5-HT₃R) is a member of a superfamily of ligand gated ion channels. All members of this family share a large degree of sequence homology and presumably significant structural similarity. A large number of studies have explored the structure-function relationships of members of this family, particularly the nicotinic and GABA receptors. This information can be utilized to gain additional insights into specific structural and functional features of other receptors in this family.     

Functional group interactions of a 5-HT3R antagonist

Background  

Lerisetron, a competitive serotonin type 3 receptor (5-HT₃R) antagonist, contains five functional groups capable of interacting with amino acids in the 5-HT₃R binding site. Site directed mutagenesis studies of the 5-HT_3AR have revealed several amino acids that are thought to form part of the binding domain of this receptor. The specific functional groups on the ligand that interact with these amino acids are, however, unknown. Using synthetic analogs of lerisetron as molecular probes in combination with site directed mutagenesis, we have identified some of these interactions and have proposed a model of the lerisetron binding site.     

Linear viscoelastic behavior of copper phthalocyanine dispersions used in printing inks

In this paper we describe the linear viscoelastic properties of copper phthalocyanine (CuPCN) dispersions that are used in the manufacturing of offset lithographic printing inks. Transmission electron microscopy shows that the primary pigment particles are rod-like and have sizes in the range of 10 to 300 nm. Steady shear measurements show that the dispersions are Newtonian at a pigment volume fraction of 0.073 and become increasingly shear thinning as the pigment volume fraction is increased. The strong shear-thinning nature of these dispersions can be attributed to the highly flocculated nature of the dispersions, which is due to interparticle attractions. The structural complexity of the dispersions also results in an unexpected linear viscoelastic response. While at low frequencies (0.1 and 1.0 Hz) the ex tent of the linear region decreases with increasing pigment concentration, at a higher frequency (10 Hz) the extent of the linear region increases with increasing pigment concentration. This increase in the linear region with increasing pigment concentration suggests that at higher frequencies the dispersion is less brittle, and that the rheological behavior is dominated by intra-aggregate associations. In addition, frequency sweeps show that the dispersions behave like a viscoelastic liquid at low pigment concentrations. However, at higher pigment concentrations (yet significantly lower than the maximum packing fraction) the dispersions behave like a cross-linking polymer at its gel point.     

Numerical Study of Ignition Process in Turbulent Shear-less Methane-air Mixing Layer

In this work, ignition process in a turbulent shear-less methane-air mixing layer is numerically investigated. A compressible large eddy simulation method with Smagorinsky sub-grid scale model is used to solve the flow field. Also, a thickened flame combustion model and DRM-19 reduced mechanism are used to compute species distribution and the heat release. Non-reacting mean and RMS axial velocity profiles and mean mixture fraction are validated against experimental data. Instantaneous mixture fraction contours show that the large bursts penetrate from the fuel stream into that of the oxidizer and vice versa and a random behaviour in the cross-stream direction. Flame kernel initiation, growth and propagation are analysed and compared with the experimental data. The ignition results show that the flame is not stable and blow-off occurs, but a more detailed investigation shows that local and short time flame stabilization exist during blow-off. During these local stabilization, heat release increased at the upstream edge of the flame. Most_upstream flame edge scalar analysis shows that the methane mass fraction has a dominant role in the local flame stabilization. OH, HO₂, CH₂O and heat release contours demonstration reveal that HO₂ and CH₂O mass fraction as well as the heat release reach a maximum on the border of the flame, but the maximum OH concentration is located in the middle of flame kernel.     

Mortar spectral element discretization of the stokes problem in axisymmetric domains

The Stokes problem in a tri‐dimensional axisymmetric domain results into a countable family of two‐dimensional problems when using the Fourier coefficients with respect to the angular variable. Relying on this dimension reduction, we propose and study a mortar spectral element discretization of the problem. Numerical experiments confirm the efficiency of this method. © 2013 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 30: 44–73, 2014