Materials Literature
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We report on the synthesis, kinetics of proteolysis by trypsin, and morphological characterization of a novel lipidated decapeptide that spontaneously self-assembles in aqueous solutions into 0.5 μm diameter hollow tubules and helices that range in length from tens to hundreds of micrometers depending on formation con…
Ultrathin layers of a new metallosupramolecular iron(II) coordination−polyelectrolyte containing 1,4-bis(2,2‘:6‘,2‘ ‘-terpyridine-4‘-yl)benzene ( 1 ) have been prepared by alternating adsorption from dilute solution. Adsorption on oppositely charged surfaces and layer-by-layer growth were investigated in situ by surfa…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSuprasupermolecules with Novel Properties: MetallodendrimersGeorge R. Newkome, Enfei He, and Charles N. MoorefieldView Author Information Center for Molecular Design and Recognition, Department of Chemistry, 4202 East Fowler Avenue, University of South Florida, Tampa, Florid…
PCR random mutagenesis in the cysE gene encoding Escherichia coli serine acetyltransferase was employed to isolate the mutant enzymes that, due to a much less feedback inhibition by L-cysteine, cause overproduction of L-cysteine and L-cystine in the recombinant strains. The L-cysteine auxotrophic and non-utilizing E.…
The complexation of poly[(acrylamidopropyl)trimethylammonium chloride] with sodium [bis(perfluorohexylethyl)-2-sulfosuccinate] (Fluowet SB) in aqueous solution results in a highly ordered mesomorphous polyelectrolyte−surfactant complex. Films prepared from the complex exhibited a remarkably low critical surface tensio…
The colligative properties of poly(propylene imine) dendrimers in methanol have been investigated with low-angle laser light scattering and vapor pressure osmometry. The molecular weights and second virial coefficients of the first five generations have been determined. The molecular weights have been found to agree w…
Density functional theory and ab initio molecular orbital theory have been used to calculate the energetics of C 2 insertion into C 9 H 12 and C 9 H 14 clusters that model unhydrided and monohydrided (100) diamond surfaces, respectively. The reaction of C 2 with either the C 9 H 12 or C 9 H 14 cluster is exothermic by…
Understanding the processes in Earth9s lower mantle requires detailed knowledge of the composition, phase, and physical properties of the mantle minerals, chiefly magnesium silicates with a perovskite structure. Navrotsky (page 1788) argues that lessons can be learned from ceramic perovskites that have been studied in…
In this work we survey selected theoretical developments for models of deposition of extended particles, with and without surface diffusion, on linear and planar substrates, of interest in colloid, polymer, and certain biological systems.
Grand canonical simulations are used to calculate adsorption isotherms of various classical gases on alkali metal and Mg surfaces. Ab initio adsorption potentials and Lennard-Jones gas-gas interactions are used. Depending on the system, the resulting behavior can be nonwetting for all temperatures studied, complete we…
The title diradical was synthesized and investigated by ESR and UV−vis spectroscopy. It was found to have a lifetime of weeks even in the presence of oxygen, and even survives brief heating in toluene up to about 60 °C. In the UV−vis spectrum, the diradical showed reversible thermochromic behavior in the −10 to 50 °C…
Using both instantaneous snapshots and simulation generated scattering data, the steady-state flow behaviour of a concentrated aggregated colloidal suspension is analysed in terms of its structure factor S(k). We find that in the shear thinning regime, unlike model hard sphere results, S(k) exhibits pre-peaks at small…
New liquid-crystal media and photoconductor materials are being utilized in spatial light modulators to increase their resolution, diffraction efficiency, speed, and sensitivity. A prototypical device developed for real-time holography applications has shown an 8% diffraction efficiency from a holographic grating with…
We study the in situ fabrication of copper sulfide nanoparticles within a three-dimensional (3D) organic-layered solid crystal of alkylammonium−metal complexes by their reaction with H 2 S gas. UV−vis spectroscopy and high-resolution electron microscopy are used to monitor the formation of the nanoparticles and to cha…
Resonant grating waveguide structures were used to fabricate narrow-bandwidth optical filters. Azopolymer films were deposited on top of slab waveguides, and surface relief gratings were optically inscribed on them to be used as couplers. This technique is a simple one-step process and produces efficient gratings with…
The in-plane correlation lengths and magnetic disorder of magnetic domains in a transition metal multilayer have been studied using neutron scattering techniques. A new theoretical framework is presented connecting the observed scattering to the in-plane correlation length and the dispersion of the local magnetization…
We calculate non-perturbatively the inelastic effects on the conductance through a conjugated molecular wire-metal heterojunction, including realistic electron-phonon coupling. We show that at sub-band-gap energies the current is dominated by quantum coherent transport of virtual polarons through the molecule. In this…
Different ways to define and to calculate the degree of spin polarization in a ferromagnet are discussed, particularly with respect to spin-polarized tunneling and Andreev reflection at the boundary between a superconductor and ferromagnet. As an example, the degrees of spin polarization for different experiments in F…
The induction of an s-wave component in a d-wave superconductor is considered. Near the {110}-oriented edges of such a sample, the induced s-wave order parameter together with d-wave component forms a complex combination d+e^{iϕ} s, which breaks the time reversal symmetry (BTRS) of the pairing state. As a result, the…
In this work we investigate the effect of gamma and ultraviolet radiations on the thermoluminescence of Brazilian calcite. The irradiated samples presented three TL peaks at 150, 245 and 320^oC (at a linear heating rate of 1.8^oC/s), with a main emission band centered at 615nm due to the ^4G \to ^6S transition of the…