Modified control grid interpolation for the volumetric reconstruction of fluid flows

Complex applications in fluid dynamics research often require more highly resolved velocity data than direct measurements or simulations provide. The advent of stereo PIV and PCMR techniques has advanced the state-of-the-art in flow velocity measurement, but 3D spatial resolution remains limited. Here a new technique is proposed for velocity data interpolation to address this problem. The new method performs with higher quality than competing solutions from the literature in terms of accurately interpolating velocities, maintaining fluid structure and domain boundaries, and preserving coherent structures.     

Implications of cosmic string-induced density fluctuations at the quark-hadron transition

We show that cosmic strings moving through the plasma at the time of a first-order quark-hadron transition in the early universe generate baryon inhomogeneities, which can survive till the nucleosynthesis epoch. We find out how these inhomogeneities actually affect the calculated values of the light element abundances. Recently a wealth of observational data from various experiments have helped to reduce the uncertainties in the values of these abundances. Using these we show that it is possible to derive constraints in the presence of cosmic strings during the quark-hadron transition.     

Activation of c-Jun N-terminal kinase is required for ultraviolet B-induced apoptosis of murine peritoneal macrophages in vitro

The mechanisms of ultraviolet B (UVB)-induced apoptosis and the role of c-Jun N-terminal kinase (JNK) mitogen activated protein kinase (MAPK) in murine peritoneal macrophages, the terminally differentiated non-dividing cells were investigated. Exposure of macrophages to UVB 100 mJ/cm2 induced rapid apoptosis concurrent with activation of JNK and mitochondrial cytochrome c release leading to procaspase-3 activation. Late into the UVB-induced apoptosis, a caspase-mediated cleavage of Bid was observed. Caspase inhibitors N-Benzylocarbonyl-Val-Asp-fluoromethyl ketone and N-Acetyl-Asp-Glu-Val-Asp-aldehyde inhibited the UVB-induced apoptosis without preventing the release of cytochrome c and JNK activation. The inhibition of JNK MAPK prevented UVB-induced apoptosis, concomitant with inhibition in cytochrome c release and procaspase-3 activation. However, it had no effect on procaspase-8 activation. These results indicate that activation of JNK MAPK upstream of caspases might play an important role in the apoptotic process of macrophages exposed to UVB irradiation.     

Nucleation of beta-hairpin structures with cis amide bonds in E-vinylogous proline-containing peptides

Synthesis and conformational studies of peptides containing the E-vinylogous prolines 1 (VPro1) and 2 (VPro2), Boc-Ala-Val-VPro1-Xaa-Leu-OMe (3, Xaa = Gly; 4, Xaa = Phe), Boc-Ala-Val-VPro2-Xaa-Leu-OMe (5, Xaa = Gly; 6, Xaa = Phe), Boc-Leu-Ile-Val-VPro1-Xaa-Leu-OMe (7, Xaa = Gly; 8, Xaa = Phe), and Boc-Leu-Ile-Val-VPro2-Xaa-Leu-OMe (9, Xaa = Gly; 10, Xaa = Phe), were carried out. It has been shown that both VPro1 and VPro2 lead to the formation of 12-membered intramolecularly hydrogen bonded structures very similar to type VI beta-turns with a cis Xaa-VPro amide bond in the major conformers in all the peptides 3-10, resulting in the nucleation of beta-hairpin type structures in these molecules in CDCl(3).     

Formation, isolation, spectroscopic properties, and calculated properties of some isomers of C(60)H(36)

Isomers of C(60)H(36) and He@C(60)H(36) have been synthesized by the Birch or dihydroanthracene reduction of C(60) and isolated by preparative high-pressure liquid chromatography. (3)He, (13)C, and (1)H NMR spectroscopic properties were then determined. A comparison of experimental chemical shifts against those computed using density functional theory (B3LYP) with polarized triple- and double-zeta basis sets for He and C,H, respectively, allowed provisional assignment of structure for several isomers to be made. Theoretical calculations have also been carried out to identify low-energy structures. The transfer hydrogenation method using dihydroanthracene gives a major C(60)H(36) isomer and a minor C(60)H(36) isomer with C(3) symmetry as determined by the (13)C NMR spectrum of C(60)H(36) and the (3)He NMR spectrum of the corresponding sample of (3)He@C(60)H(36). In view of the HPLC retention times and the (3)He chemical shifts observed for the Birch and dihydroanthracene reduction products, the two isomers generated by the latter procedure can be only minor isomers of the Birch reduction. A significant energy barrier apparently exists in the dihydroanthracene reduction of C(60) for the conversion of the C(3) and C(1) symmetry isomers of C(60)H(36) to the T symmetry isomer previously predicted by many calculations to be among the most stable C(60)H(36) isomers. Many of the (1)H NMR signals exhibited by C(60)H(36) (and C(60)H(18), previously reported) are unusually deshielded compared to "ordinary" organic compounds, presumably because the unusual structures of C(60)H(36) and C(60)H(18) result in chemical shift tensors with one or more unusual principal values. Calculations clearly show a relationship between exceptionally deshielded protons beta to a benzene ring in C(60)H(18) and C(60)H(36) and relatively long C-C bonds associated with these protons. The additional information obtained from 1D and 2D (1)H NMR spectra obtained at ultrahigh field strengths (up to 900 MHz) will serve as a critical test of chemical shifts to be obtained from future calculations on different C(60)H(36) isomers.     

Clusters of glycolic acid with three to six water molecules

Semiempirical, ab initio, and density functional theory calculations are used to locate many low-energy minima on the potential energy surfaces of the CH2OHCOOH-(H2O)n complexes with n = 3,4,5,6. In the clusters with three, four, and five water molecules, the lowest-energy structure consists of a (H2O)n complex, not necessarily of lowest energy, hydrogen bonded to the carboxylic group of the glycolic acid. The lowest-energy structure for n = 6 is similar except that the water hexamer is hydrogen bonded to both the carboxylic and alpha-hydroxyl groups of the acid. In all the lowest-energy clusters, the intramolecular hydrogen bond remains intact in the glycolic acid.     

Polarization Green's function with multiconfiguration self-consistent-field reference states

The polarization Green's-function formalism in the superoperator notation of Goscinski and Lukman is re-derived using a multiconfiguration self-consistent-field (MC -SCF ) reference state to establish the superoperator metric. The potential advantages of employing this more general reference state in Green's-function theories and certain inherent weaknesses associated with the traditional Hartree–Fock or Rayleigh–Schrödinger perturbation theory reference state choices are briefly discussed. The Hermiticity of the superoperators is analyzed within the framework of the MC –SCF reference state. Using a concept of order appropriate for this reference state choice, explicit formulas and computational procedures for the implementation of this Green's-function theory are presented and specialized to include terms consistent through second order.     

New insight into the synthesis of a novel azo-based optically active polyamidoamine side chain dendritic polyester architectural photoswitch

[reaction: see text] A novel chiral polyamidoamine side chain dendritic polyester 4 has been synthesized and found to be a photoresponsive system undergoing reversible E/Z photochemical/thermal isomerization of azo units. Thorough characterization (IR,UV-vis, NMR, FAB-MS, elemental analysis, optical rotation, etc.) were performed to ascertain the structures of dendrimers 2, 3, and 4. The intrinsic viscosity of 4 at 36 degrees C in CHCl(3) was found to be 0.48 dl/g.