Synthesis of 4-alkoxy-8-hydroxyquinolines

Quinolines with a hydroxyl group at the 8-position and an alkoxy group at the 4-position are rare compounds. In this paper the synthesis of five 4-alkoxy-8-hydroxyquinolines is reported. The key reaction in the synthetic route is a selective protection of the hydroxyl group at C-atom 8 in 4,8-dihydroxyquinoline with a tosyl group and the hydrolytic removal of the protective group after the alkylation. The tosyl group is stable during the alkylations with various alkylating agents in the presence of sodium hydride.     

On all-optical laser cleaning and inspection of contaminated concave metal surfaces

A technique for all-optical laser cleaning and surface quality monitoring of concave metal surfaces is suggested. Contaminated pharmaceutical punches from a tablet compression machine were cleaned using high-energy laser pulses. Image information obtained from a diffractive-optical-element-based sensor was used in inspection of the surface quality change of the concave punches due to laser cleaning. Alternative method for mechanical cleaning of punches is introduced, which is based on simultaneous laser cleaning and surface quality inspection of the punches.     

Existence of classical solutions for compressible viscoelastic fluids of Oldroyd type past an obstacle

This paper deals with the existence and uniqueness of stationary solutions for the equations modelling the steady flow of compressible viscoelastic fluids of Oldroyd type in an exterior domain. The existence proof is based on an appropriate decomposition of the original nonlinear set of equations into auxiliar problems (Neumann problem for the Laplacian, Oseen problem, two transport equations) and on a fixed point argument in a suitable functional setting. Copyright © 1999 John Wiley & Sons, Ltd.     

Interactions between local anesthetics and lipid dispersions studied with liposome electrokinetic capillary chromatography

In the case of local anesthetic intoxication, intravenous administration of lipid-based Intralipid dispersion (Fresenius Kabi) can be used for the entrapment of hydrophobic drugs. Our long-term aim is to develop a sensitive, efficient, and non-harmful lipid-based formulation to specifically trap harmful substances. In this study liposome electrokinetic capillary chromatography (LEKC) was used to study the interactions between local anesthetics and Intralipid or liposome dispersions. Intralipid dispersion and extruded liposomes with different concentrations of 1-palmitoyl-2-oleyl-sn-glycerophosphatidylcholine (POPC), phosphatidylglycerol, cardiolipin, cholesterol, oleic acid, and linoleic acid were used as a pseudostationary phase in LEKC and their interactions with lidocaine, prilocaine, and bupivacaine were studied. POPC liposomes containing 1 mol% of palmitoyl-2-[12-[(7-nitro-2-1,3-benzoxadiazol-4-yl)amino]dodecanoyl]-sn-glycero-3-phosphocholine as a fluorescent marker were used for the first time in LEKC connected with laser-induced fluorescent detection in order to calculate the retention factor for anesthetics.     

Calculations of nuclear quadrupole coupling in noble gas-noble metal fluorides: interplay of relativistic and electron correlation effects

The nuclear quadrupole coupling constants (NQCCs) of noble gas and noble metal nuclei in the recently found noble gas-noble metal fluorides (NgMF, where Ng=Ar,Kr,Xe and M=Cu,Ag,Au) are obtained theoretically by high-level ab initio calculations, where both relativistic and electron correlation effects are included, and compared to experimental results. Fully relativistic four-component Dirac-Hartree-Fock (DHF) calculations are carried out at the basis set limit for electric field gradient that couples with the electric quadrupole moment of the nucleus, and uncorrelated relativistic effects are extracted by comparing DHF results to nonrelativistic (NR) HF calculations. Electron correlation effects are investigated both at fully relativistic second-order Moller-Plesset (DMP2) and at NR MP2 levels of theory, as well as at the NR coupled-cluster singles and doubles with perturbational triples [CCSD(T)] level. The validity of the approximation where relativistic effects, on the one hand, and nonrelativistically obtained correlation effects, on the other hand, are evaluated separately and assumed to be additive, is investigated by comparison with the DMP2 results. Inclusion of relativistic effects is shown to be necessary for obtaining the correct NQCC trends as the nucleus of interest and/or its neighbors become heavier. Electron correlation treatment is needed for approaching quantitative agreement with the experimental NQCCs. The assumption of additive electron correlation and relativistic effects, corresponding to the NR correlation treatment added on top of relativistic DHF data, gives qualitatively correct noble gas NQCCs. For noble metal NQCCs, correlation treatment at the relativistic level of theory is mandatory for reaching agreement with experimental results. Current work also confirms the experimental trends of NQCCs, which have been taken as an indication of nearly covalent interaction between noble gas and noble metal in the heaviest present systems, especially in XeAuF.     

A mass spectrometric study of metal binding to osteocalcin

Electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry was used to investigate Ca(2+), Mg(2+), and La(3+) binding to bovine bone osteocalcin (OCN). OCN was shown to bind 3 mol Ca(2+) per mol protein. There was also evidence for the presence of four additional metal binding sites. Ca(2+) increased the formation of the OCN dimer. Mg(2+) bound to OCN to the same extent as Ca(2+) but did not induce the dimerization of OCN. La(3+) bound to a lesser extent than either Ca(2+) or Mg(2+) to OCN and, like Mg(2+), did not influence dimerization. Each Gla residue of OCN participates in Ca(2+) binding, whereas Mg(2+) binding may occur preferentially at sites other than Gla residues. This implies that the different natures of Ca(2+)- and Mg(2+)-containing OCN complexes influence the tendency of OCN to form a dimer.     

Molecular dynamics simulations for human CAR inverse agonists

Constitutive androstane receptor (CAR), along with pregnane x receptor (PXR), is an important metabolic sensor in the hepatocytes. Like all other nuclear receptors (NRs), CAR works in concert with coregulator proteins, coactivators, and corepressors which bind to the NRs. The main basis for the receptor to distinguish between coactivators and corepressors is the position of the C-terminal helix 12 (H12), which is determined by the bound NR ligand. CAR, having constitutive activity, can be repressed or further activated by its ligands. Crystal structure of human CAR bound to an agonist and a coactivator peptide is available, but no structural information on an inverse agonist-bound human CAR and a corepressor exists. In our previous molecular dynamics (MD) studies, no corepressor peptide was included. Therefore, probably due to the strong interactions which keep the relatively short H12 of CAR in the active position, the structural changes elicited by inverse agonists were very subtle, and H12 of CAR seemed to more or less retain its active conformation. Here, we have run a series of MD simulations to study the movement of H12 in the presence of both activating and repressing ligands as well as a corepressor peptide. The presence of the corepressor on the coregulator surface of CAR induced a clear shift of H12 of the inverse agonists-bound CAR. In general, H12 moved toward H10 and not away from the ligand binding domain, as seen in some other NRs. However, H12 of CAR is short enough that this movement seems to be adequate to accommodate the binding of the corepressor.     

Surface characteristics and wetting properties of sol–gel coated base paper

Two hybrid coatings synthesized by using alkoxysilanes as precursors in a sol–gel process, differing from each other in terms of the organic components in alkoxysilanes, have been developed to improve the water repellent properties of base paper. The sol–gel‐coated base paper samples were characterized by scanning electron microscopy, atomic force microscopy, confocal laser scanning microscopy, X‐ray photoelectron spectroscopy, time‐of‐flight secondary ion mass spectrometry, and contact angle measurements. The sol–gel coatings were found to clearly change the surface properties of base paper. Thin coating layers were formed on base paper surfaces. The topographical data indicated the formation of discontinuous thin films; the time‐of‐flight secondary ion mass spectrometry analyses confirmed that the coatings were covering the fibres but only partially covered the fibre–fibre intersections. Water and the subsequent heat treatment used as a reference treatment reduced the surface roughness and porosity and slightly changed the surface chemistry of the base paper. The wettability and absorptivity of base paper was clearly reduced by the applied coatings. Copyright © 2011 John Wiley & Sons, Ltd.     

Microwave backscattering by nonspherical ice particles at 5.6 GHz using second-order perturbation series

Scattering of microwaves by an ensemble of nonspherical ice particles is studied using a scattering model based on a second-order perturbation series at 5.6 GHz (C-band). Particle shapes are defined using a Gaussian random sphere geometry. Particle inhomogeneity is taken into account using three different effective-medium approximations: Maxwell–Garnett, Bruggeman, and Coherent Potential mixing rules. By systematically varying particle size, liquid water content, Gaussian shape parameters, and internal structure, it is found that liquid water content is the most important factor for the co-polarized backscattering; the shape is relatively unimportant. For depolarized backscattering, the shape is of fundamental importance, although the other factors are significant too. Surprisingly, the type of nonsphericity is found to be important for depolarization even for scatterers that are in the Rayleigh region: elongated targets depolarize clearly stronger than more irregular shapes. This finding seems not to be strongly size dependent, at least for size parameters from 0.0059 to 0.47, and indicates that the accurate modeling of shape is important for polarization quantities even in the Rayleigh region.