Materials Literature
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The four-dimensional +-J random-bond Ising model is studied using ground-state calculations. System sizes up to N=6^4 spins are considered. Here it is found that the ferromagnetic-spin glass transition occurs at a critical concentration p_c=0.28(1) of the antiferromagnetic bonds, which is comparable to values found pr…
Circular dichroism spectroscopy has been used to study the self-assembly of two series of m-phenylene ethynylene oligomers in highly polar solvents. The helical conformation of shorter oligomer lengths was found to be stabilized in aqueous acetonitrile solutions, while longer oligomers began to interact intermolecular…
Two dendritic peptides containing a branched lysine core and up to eight azobenzene moieties in the periphery were synthesized on solid support employing the omega-amino acid 4-(aminomethyl)phenylazobenzoic acid. With an additional peptidic tail consisting of an oligolysine portion, water solubility was achieved for t…
In biological systems the detailed structure of macromolecules is usually encoded genetically. Here we show that the synthesis and structure of certain biopolymers can be directed by taking control of the reaction pathways in microorganisms to direct the reaction kinetics. The biological synthesis of polyhydroxyalkano…
A method to prepare a new class of dianhydrides is outlined. A representative polyimide, PPI, has been prepared by a two-stage condensation reaction between polyphenylated dianhydride and 3,6-diamino-9-hexylcarbazole. The PPI is readily soluble in common organic solvents, and shows only 10 wt % loss at 555 °C.
To mimic the regulation mechanisms and the selective chemistry of enzymes in the absence of a protein environment, a novel bio-inspired catalyst design strategy is applied with photosensitive coordination compounds acting as photocatalytic artificial enzymes (photozymes). As an example, a robust synthetic oxidoreducta…
Finely divided Pd particles (2−3 nm in diameter) were synthesized by the reduction of Pd 2+ precursor ions in the presence of cationic (myristyltrimethylammonium bromide, MTA + Br - ) or anionic (sodium dodecyl sulfate, Na + DS - ) surfactants. The protective adsorption layer of the ionic surfactants around the partic…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTHigh Activity Enzyme Microcrystal Multilayer FilmsWen Jin, Xiangyang Shi, and Frank CarusoView Author Information Max Planck Institute of Colloids and Interfaces D-14424 Potsdam, Germany Cite this: J. Am. Chem. Soc. 2001, 123, 33, 8121–8122Publication Date (Web):July 2…
Production of biodegradable thermoplastics, polyhydroxyalkanoates (PHAs), from organic wastes may provide multiple benefits to environmental conservation efforts. In this study, microfiltration-coupled reactors were set up to study the dynamic behavior of a typical PHA-producing bacteria, Ralstonia eutropha, fed with…
Reactions of CuCl with Te(Ph)SiMe3 and solublizing trialkylphosphine ligands afford a series of polynuclear copper-phenyltellurolate complexes that has been structurally characterized. The formation of the complexes is found to be highly dependent on the ancillary phosphine ligand used. The synthesis and structures of…
We describe a new approach to making luminophores that display long emission wavelengths, long decay times, and high quantum yields. These luminophores are covalently linked pairs with a long-lifetime resonance-energy-transfer donor and a long-wavelength acceptor. The donor was a ruthenium (Ru) metal-ligand complex. T…
BACKGROUND: Chorismate mutases of the AroQ homology class are widespread in the Bacteria and the Archaea. Many of these exist as domains that are fused with other aromatic-pathway catalytic domains. Among the monofunctional AroQ proteins, that from Erwinia herbicola was previously shown to have a cleavable signal pept…
The adsorption of the amphiphilic diblock copolymer poly(2-(dimethylamino)ethyl methacrylate- block -methyl methacrylate) (DMA−MMA) at the mica/solution interface has been studied, over a range of solution pH values, using in situ atomic force microscopy. In contrast to the adsorption of the homopolymer poly(2-(dimeth…
Using the ab initio full-potential linearized augmented-plane-wave approach, we have studied the role of surface oxygen vacancies on the characteristics of palladium deposition on the MgO (100) surface. In agreement with recent theoretical evidence, we find that the adsorption energy of a single Pd atom is considerabl…
The synthesis of a new sandwich lutetium(III) bisphthalocyanine substituted with hexylthio groups (1), [(C6H1)S)8-Pc]2Lu, is described. The compound is very soluble in most common organic solvents and has been fully characterized (elemental analysis, IR, 1H and 13C NMR, UV-vis spectroscopy, mass spectrometry). The che…
Aqueous dispersions of different smectite-type clay minerals were probed by ion-exchange of methylene blue (Mb). The evolution of the absorption spectra with time demonstrates the importance of the strength of the Mb−clay surface interaction, which is affected by the colloidal nature of the suspension and typical clay…
A phase diagram as a function of molecular weight ratio and blend composition was constructed for the binary blends of nearly symmetric polystyrene- block -polyisoprene (PS−PI) copolymers. In this study we prepared four series of binary blends, and every blend consists of a copolymer, hereafter designated as α, whose…
We report a study of the self-condensing group transfer copolymerization of the initiator−monomer (“inimer”) 2-(2-methyl-1-triethylsiloxy-1-propenyloxy)ethyl methacrylate (MTSHEMA) with methyl methacrylate (MMA). The highly branched polymethacrylates were characterized by multidetector SEC and NMR. Kinetic measurement…
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTTemperature Dependence of Segmental and Terminal Relaxation in Atactic Polypropylene MeltsC. M. Roland, K. L. Ngai, P. G. Santangelo, XH. Qiu, M. D. Ediger, and D. J. PlazekView Author Information Naval Research Laboratory, Washingt…
Abstract The effect of blending crosslinked linear low‐density polyethylene (cLLDPE) on the rheological properties and foam processability of linear low‐density polyethylene was studied. A small addition of cLLDPE, which had a low density of crosslink points, enhanced strain‐hardening behavior in the elongational visc…