On heavy baryon decay form factors

An(n?1)/2+1 parameter, solution of the Yang Baxter equation is presented giving rise to the quantum Group \(GL_{X;q_{ij} } (n)\) . Determinant and inverse are constructed. The group acts covariantly on a quantum vector space of non-commutative coordinates. The associated exterior space can be identified with the differentials exhibiting a multiparameter deformed differential calculus following the construction of Wess and Zumino.     

Influence of initial conditions on compressible vorticity dynamics

Prompted by the lack of a unique choice of pressure (P) and density () fields for a compressible free vortex and by the observed dependence of turbulence dynamics on initial P and in compressible simulations, we address the effects of initial conditions on the evolution of a single vortex, on the prototypical phenomenon of vortex reconnection, and on two-dimensional turbulence. Two previous choices of initial conditions used for numerical simulations of compressible turbulence have been: (i) both P and uniform (constant initial conditions, CIC), and (ii) uniform with P determined from the Poisson equation (constant density initial conditions, CDIC). We find these initial conditions to be inappropriate for compressible vorticity dynamics studies. Specifically, in compressible reconnection, the effects of baroclinic vorticity generation and shocklet formation cancel each other during early evolution for CDIC, thus leading to almost incompressible behavior. Although CIC captures compressibility effects, it incorrectly changes the initial vorticity distribution by introducing strong acoustic transients, thereby significantly altering the evolving dynamics.Here, a new initial condition, called polytropic initial condition (PIC), is proposed, for which the Poisson equation is solved for initially polytropically related P and fields. PIC provides P and distributions within vortices which are consistent with those observed in shock-wedge interaction experiment and also leads to compressible solutions with no acoustic transients. At low Mach number (M), we show that the effects of all these three initial conditions can be predicted by low-M asymptotic theories of the Navier-Stokes equations. At high M, it is shown here that inappropriate initial conditions may alter the evolutionary dynamics and, hence, lead to wrong conclusions regarding compressibility effects. We argue that PIC is a more appropriate choice.D. Virk acknowledges financial support of the Advanced Study Program at NCAR, Boulder, for 2 years during graduate studies. Part of this work and the writing of the paper have been supported by NSF Grant CTS-9214818.     

Cesium fluoride-Celite: a solid base for efficient syntheses of aromatic esters and ethers

Coupling reactions of a number of aromatic and heteroaromatic phenols with alkyl, acyl or benzoyl halides in acetonitrile with cesium fluoride-Celite are described, demonstrating that this reagent provides an efficient, convenient and practical method for the syntheses of aromatic esters and ethers.     

DOTA-Tyr3-Octreotate: Labeling with β-emitting radionuclides for the preparation of potential therapeutic radiopharmaceuticals

Radiolabeled somatostatin analogues, including octreotate have been used for targeted radiotherapy of neuroendocrine tumors such as lymphoma, breast cancer, small-cell lung cancer and melanoma. In this paper, studies on the optimization of the production of ¹⁷⁷Lu, ¹⁶⁶Ho and ¹⁵³Sm radionuclides in Pakistan Atomic Research Reactor (PARR-I) and the investigations on the labeling of DOTA-Tyr-3 Octreotate with ¹³¹I, ¹⁷⁷Lu, ¹⁶⁶Ho and ¹⁵³Sm have been reported. The labeled DOTA-Tyr3-Octreotate complexes were found to be stable in acetate/ascorbate buffer and saline at room temperature (18–22°C). The biodistribution studies of ¹⁷⁷Lu-DOTA-Tyr-3 Octreotate in rat model indicated that the critical organ for this complex was the pancreas and the excretion route was through kidney.     

catena‐Poly­[[tri‐n‐butyl­tin]‐μ‐N‐(1‐naphthyl)­maleamato]

The crystal structure of catena‐poly­[[tri‐n‐butyl­tin]‐μ‐3‐(1‐naph­thyl­amino­carbonyl)­acrylato‐κ²O¹:O³], [Sn(C₄H₉)₃(C₁₄H₁₀NO₃)]_n, is composed of polymeric chains wherein the metal center exhibits a distorted trigonal‐bipyramidal geometry, with three n‐butyl groups defining the trigonal plane [mean Sn—C 2.133 (7) Å] and the axial positions being occupied by the carboxyl­ate O atoms of two different N‐(1‐naphthyl)­maleamate ligands with inequivalent Sn—O distances [2.167 (4) and 2.457 (4) Å]. The N‐(1‐naphthyl)­maleamate fragment forms an essentially planar seven‐membered ring involving an intramolecular N—H?O hydrogen bond.     

Three new sesquiterpene hemiacetals from Achillea vermicularis

Three new sesquiterpene hemiacetals, tentatively named as achilleanone (1), vermiculone (2) and vermicularone (3) have been isolated from Achillea vermicularis, along with three other known compounds beta-amyrin, oleonolic acid and beta-sitosterol. The structure elucidation of new compounds was based primarily on two-dimensional (2D) NMR techniques including Nuclear Overhauser Effect/Enhancement (NOE), heteronuclear multiple quantum coherence (HMQC), heteronuclear multiple bond correlation (HMBC) and nuclear overhauser effect spectroscopy (NOESY) experiments. Compounds 1, 2 and 3 have displayed inhibitory potential against lipoxygenase enzyme in a concentration-dependent fashion with promising IC50 values.     

PHYTOCHROME MODELS: PART 10. CONCENTRATION,SONICATION AND TEMPERATURE AFFECTING THE POPULATION OF THE GROUND-STATE CONFORMERS OF BILIVERDIN DIMETHYL ESTER IN SOLUTION*

UV-vis absorption and fluorescence spectroscopy were used to show that in alcoholic solutions (methanol, ethanol, 2-methylbutan-1-ol, and 2-octanol) concentration, temperature, and sonication affect the relative populations of the more rigid stretched and the more flexible helically coiled conformers of biliverdin dimethyl ester. In aromatic solvents, e.g. toluene, no such effects could be detected. At concentrations larger than 3 10^-5M in the alcoholic solvents aggregates and monomeric coiled species prevail. Upon dilution, the fraction of stretched monomeric conformers increases. Heating and sonication at concentrations smaller than 3 10^-5M further and irreversibly increase the fraction of the stretched conformers. The activation parameters for this change are compatible with the assessment that no equilibrium is attained between the two families of conformers even after several hours at room temperature, since the barriers arc higher than kT at this temperature. The present results and those previously reported on the excited-state processes of biliverdin dimethyl esters are explained on the basis of a scheme in which the eight possible ring B/C isomers of biliverdin dimethyl ester are interconverted through intra-and intermolecular proton transfers, rotations around C-C single bonds, and E-Z photoisomerizations around C = C double bonds.     

One-pot synthesis of aryl fluorides by [3+3] cyclization of 1,3-bis(silyl enol ethers) with 2-fluoro-3-silyloxy-2-en-1-ones

Functionalized aryl fluorides were regioselectively prepared by [3+3] cyclization of 1,3-bis(silyl enol ethers) with 2-fluoro-3-silyloxy-2-en-1-ones.