Palladium-catalyzed direct allylation of fluorinated benzothiadiazoles with allyl chlorides

A palladium catalyzed cross-coupling of fluorinated benzothiadiazoles (FBTs) with allyl chlorides is reported. The significant feature of this method is synthetic simplicity, providing a straightforward access to unsymmetrical and symmetrical alkylated FBT derivatives that are of interest in organic electronic and optoelectronic materials.     

Pharmacokinetics and tissue distribution study of clevidipine and its primary metabolite H152/81 in rats

This present study was designed to investigate the pharmacokinetic profiles and tissue distribution characteristics of clevidipine and its primary metabolite H152/81 in rats following a single intravenous administration of clevidipine butyrate injectable emulsion. For this study, a sensitive and selective liquid chromatography–tandem mass spectrometry (LC–MS/MS) method was established and validated for the simultaneous quantitation of clevidipine and H152/81 in rat whole blood and various tissues. A Hedera ODS‐2 column with two gradient elution programs was employed for the troubleshooting of matrix effect on the detection of analytes among different biological samples. The experimental data showed that clevidipine represented quick elimination from blood with a half‐life of about 4.3 min and rapid distribution in all of the investigated tissues after administration; the highest concentration of clevidipine was found in the heart whereas the lowest concentration was detected in the liver. In addition, clevidipine was almost undetectable in most tissues except for heart and brain at 90 min post‐dosing, suggesting that there was no apparent long‐term accumulation in rat tissues. For H152/81, the peak concentration of 3714 ± 319 ng/mL occurred at 0.129 ± 0.048 h, the half‐life was 10.08 ± 1.45 h and area under the concentration–time curve was 42091 ± 3812 ng h/mL after drug administration. In addition, H152/81 was found at significant concentration levels in all tissues, in descending order of lung, kidney, heart, liver, spleen and brain at each time point. The results of current study offer useful clues for better understanding the distribution and metabolism of clevidipine butyrate injectable emulsion in vivo.     

Lasing in an e beam pumped Ar-N2-mixture at 406 nm

An Ar−N₂-mixture was excited by a relativistic e-beam in a longitudinal pumping geometry. Lasing is observed for the trasitions from the N₂(C) to the lower three vibrational states of N₂(B) at λ=337, 358, and 380 nm and for the first time also to the fourth vibrational state at λ=406 nm.     

Linewidth studies on the Kr+ 469.4 nm and 473.9 nm lines excited in a helium-krypton hollow cathode discharge

Collisional and Doppler linewidths (v _C and v _D ) of the 469.4 nm and 473.9 nm Kr ion lines were measured in a He-Kr hollow cathode discharge using Fabry-Perot technique. A linear dependence of v _C on He pressure was found for both lines. Significant differences were found between the temperature values deduced from the v _D -s of the two lines, and an unexpected temperature dependence of the broadening parameter for the Kr⁺ 469 nm line was also observed. The temperature difference between the two lines is explained by excitation of the upper level of the 469 nm line by second kind collisions between metastable He atoms and ground-state Kr ions, while the temperature dependence of the broadening parameter of the Kr⁺ 469 nm line is suggested to be due to the inverse process.     

Laser action in an indium hollow cathode discharge

Hollow cathode discharge excitation of indium is shown to produce laser action at 468.1, 689.2, 1342.8, and 1720nm. The cw468.1 nm and 1720 nm ionic lines are excited by charge exchange effect whereas the 689.2 nm cw ionic line is excited by a radiative cascade. The 1342.8 nm atomic line appears in the afterglow of the pulsed discharge and its population inversion is produced by recombination of the indium ions and the electrons. Shanghai Institute of Optics and Fine-Mechanics, Academia Sinica. Research Fellow 1979–1980 of the Alexander-von-Humboldt-Stiftung     

On special rational curves in Grassmannians

Numerical and geometric characterizations, among all morphisms , of those which are -equivalent to the canonical morphism induced by the Morita equivalence –, are presented. The author was partially supported by KBN grants 1P03A 036 26 and 115/E-343/SPB/6.PR UE/DIE 50/2005-2008. Received: 10 September 2005     

CLP-compactness for topological spaces and groups

We study CLP-compact spaces (every cover consisting of clopen sets has a finite subcover) and CLP-compact topological groups. In particular, we extend a theorem on CLP-compactness of products from [J. Steprāns, A. Šostak, Restricted compactness properties and their preservation under products, Topology Appl. 101 (3) (2000) 213-229] and we offer various criteria for CLP-compactness for spaces and topological groups, that work particularly well for precompact groups. This allows us to show that arbitrary products of CLP-compact pseudocompact groups are CLP-compact. For every natural n we construct:

(i)

a totally disconnected, n-dimensional, pseudocompact CLP-compact group; and

(ii)

a hereditarily disconnected, n-dimensional, totally minimal, CLP-compact group that can be chosen to be either separable metrizable or pseudocompact (a Hausdorff group G is totally minimal when all continuous surjective homomorphisms G→H, with a Hausdorff group H, are open).

     

Explicit Mumford isomorphism for hyperelliptic curves

Using an explicit version of the Mumford isomorphism on the moduli space of hyperelliptic curves we derive a closed formula for the Arakelov-Green function of a hyperelliptic Riemann surface evaluated at its Weierstrass points.     

Valuations dominating regular local rings and proximity relations

We study zero-dimensional valuations dominating a regular local ring of dimension n≥2. For this we introduce the proximity matrix and the multiplicity sequence (extending classical definitions of the case n=2) that are associated with the sequence of the successive quadratic transforms of the ring along the valuation. We describe the precise relations between these invariants and study their properties.