Weak-type normal families of holomorphic mappings in Banach spaces and characterization of the Hilbert ball by its automorphism group

We present a characterization of the open unit ball in a separable infinite dimensional Hilbert space by the property of automorphism orbits among the domains that are not necessarily bounded. This generalizes the recent work of Kim and Krantz [6]. Key new features of this article include: a lower bound estimate of the Kobayashi metric and distance near a pluri-subharmonic peak boundary point of the domains in Banach spaces, an effective localization argument, and an improvement of weak-type convergence of sequences of biholomorphic mappings of domains in Banach spaces.     

Density-fluctuation-induced swelling of polymer thin films in carbon dioxide

We report an anomalous swelling of polymer thin films in carbon dioxide (CO(2)) which is associated (in both locus and form) with the density fluctuation ridge that forms along the extension of the coexistence curve of gas and liquid in the P-T phase diagram. Neutron reflectivity results showed that CO(2) could be sorbed to a large extent ( approximately 60%) in thin polymer films even when the bulk miscibility of the polymer with CO(2) is very poor. The anomalous swelling is found to scale with the polymer radius of gyration (R(g)) and extends to a distance approximately 10 R(g).     

Cationic Phosphonolipids Containing Quaternary Phosphonium and Arsonium Groups for DNA Transfection with Good Efficiency and Low Cellular Toxicity**

Replacing the ammonium polar head in cationic lipids 1 (A=N) by a phosphonium or an arsonium group (A=P, As) improves their properties as synthetic vectors for DNA transfection. The increased volume of the cationic head is supposed to modify the interactions of the vector with the solvent and DNA.     

Microwave spectrum,structure, and chemical bonding of trimethylbromosilane

The microwave spectrum of trimethylbromosilane (trimethylsilylbromide) has been investigated in the 26.5–40.0-GHz region. Spectra of several isotopic species have been observed, including the previously unreported spectrum of the ¹H¹²C³⁰Si⁸¹Br species, which yielded a B rotational constant of 1440.92 ± 0.02 MHz. From the experimental data it has been possible to derive the following structural parameters: SiBr = 2.235 ± 0.002 Å, SiC = 1.856 ± 0.010 Å, and ∠CSiBr = 107.5 ± 0.1°. The results have been compared to other relevant data and discussed in terms of prevailing chemical bonding principles.     

Polyphenols deriving from chalcones: investigations of redox activities

The redox properties of a series of hydroxychalcones (a group of polyphenols abundantly present in plants) were investigated by cyclic voltammetry. As for many polyphenols, their beneficial properties have been mainly related to their antioxidant activities, which in turn are directly associated to their redox behavior. Two types of radicals can be produced that are localized on either one of the two aromatic systems. Their thermodynamic and kinetic parameters were extracted and compared to the predictions of density functional theory calculations. When at least one OH is present on each ring, their behaviors are dominated by the conjugated system: phenolic ring A-double bond-ketone, which is the only one to be oxidized. However, the redox properties of this conjugated system are strongly influenced by the presence of ring B. When an OH is present on ring B, an important feature is the existence of strong hydrogen bonding that remains almost unmodified even when ring A is oxidized. It does not considerably change the thermodynamics of ring A but strongly increases the rigidity of the molecule that remains planar under the neutral, anionic, or radical forms. Oxidation potentials of the phenolates range between 0.1 and 0.2 V versus a saturated calomel electrode, which correspond to species that are very easy to oxidize and lead to the rapid formation of nonradical species, underlining the potential antioxidant properties of these molecules.     

Enhancement of single-molecule fluorescence detection in subwavelength apertures

We report the experimental proof of molecular count rate enhancement (up to 6.5-fold) and lifetime reduction for single fluorescent molecules diffusing in subwavelength apertures milled in aluminum films. The observed enhancement dependence with the aperture diameter agrees qualitatively with numerical electromagnetic computations of the excitation power density into the aperture volume.     

Nonalgebraizable real analytic tubes in ℂ<Superscript><Emphasis Type="Italic">n</Emphasis></Superscript>

We give necessary conditions for certain real analytic tube generic submanifolds in ⁿ to be locally algebraizable. As an application, we exhibit families of real analytic non locally algebraizable tube generic submanifolds in ⁿ. During the proof, we show that the local CR automorphism group of a minimal, finitely nondegenerate real algebraic generic submanifold is a real algebraic local Lie group. We may state one of the main results as follows. Let M be a real analytic hypersurface tube in ⁿ passing through the origin, having a defining equation of the form v= (y), where (z,w)=(x+iy,u+iv)^n–1×. Assume that M is Levi nondegenerate at the origin and that the real Lie algebra of local infinitesimal CR automorphisms of M is of minimal possible dimension n, i.e. generated by the real parts of the holomorphic vector fields _z1,...,_{z n–1},_w. Then M is locally algebraizable only if every second derivative ²_{yky l}; is an algebraic function of the collection of first derivatives _y1,,_ym.Mathematics Subject Classification (2000): 32V40, 32V25, 32H02, 32H40, 32V10