Materials Literature
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The effects of whey protein hydrolysis on film oxygen permeability (OP) and mechanical properties at several glycerol-plasticizer levels were studied. Both 5.5% and 10% degree of hydrolysis (DH) whey protein isolate (WPI) had significant effect (p </= 0.05) on film tensile properties compared to unhydrolyzed WPI. Hydr…
The primary component of the amyloid plaques in Alzheimer's disease (AD) is a highly ordered fibril composed of the 39−43 amino acid peptide, β-amyloid (Aβ). The presence of this fibril has been correlated with both the onset and severity of the disease. Using a combination of synthetic model peptides, solid-state NMR…
The observed anisotropies of surface vibrations for unreconstructed FCC metal (110) surfaces are often reversed from the "common sense" expectation. The source of these reversals is investigated by performing ab initio density functional theory calculations to obtain the surface force constant tensors for Ag(110), Cu(…
Ein in Wasser hergestellter heterogener Katalysator ist eindeutig sauberer und sollte zu saubereren Synthesen führen. In überkritischem Wasser wird La2CuO4 schneller gebildet und hat eine größere Oberfläche sowie eine höhere Aktivität bezüglich der Oxidation von CO als das entsprechende durch „traditionelle”︁ Keramiks…
Ein mikroporös/makroporöses Material konnte auf einfache Weise aus Kieselgur und einem siliciumreichen Zeolith hergestellt werden. Im Bild sind rasterelektronenmikroskopische Aufnahmen des Materials in zwei Vergrößerungen (links, Mitte) und die Anordnung der darauf ausgefällten Zeolithkristalle (rechts) gezeigt. Diese…
SBA-15 mesoporous silicates with surface functional groups were synthesized by cohydrolysis of tetraethoxyorthosilicate and ethyl-, carboxylate-, and ethylenediaminetriacetic acid-functionalized organosilanes (ETES, CTES, EDATAS, respectively) using the nonionic surfactant poly(ethylene oxide)−poly(propylene oxide)−po…
A heterogeneous catalyst prepared in water is, clearly, a cleaner one that leads to cleaner syntheses. La2CuO4 formed in supercritical water is produced more quickly, has a higher surface area, and a greater activity towards CO oxidation than the corresponding materials prepared by “traditional” ceramic synthesis. The…
Hexameric building blocks are found in a range of materials, such as hydrocarbons and water. Using water as a model compound, this Highlight identifies some of the important new results, from both the theoretical and experimental viewpoints, in the characterization of stable hexameric structures. The picture shows the…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTExperimental Observation of Non-Aufbau Behavior: Photoelectron Spectra of Vanadyloctaethylporphyrinate and Vanadylphthalocyanine†Barry L. Westcott, Nadine E. Gruhn, Laura J. Michelsen, and Dennis L. LichtenbergerView Author Information Department of Chemistry Central C…
Tailored microcavities with good size and shape selectivity can be created within long-chain molecular layers assembled in ordered nanoporous channels by using a molecular imprinting technique. The microcavities can be opened or closed by changing the conformations of the molecular chains (see picture).
Porphyrins react readily with organolithium reagents, preferentially in the meso positions. The overall reaction is a nucleophilic substitution and proceeds via initial reaction of the organic nucleophile with a meso carbon yielding an anionic species which is hydrolyzed to a porphodimethene (5,15-dihydroporphyrin), f…
Particles in the nanometer size range are attracting increasing attention with the growth of interest in nanotechnological disciplines. Nanoparticles display fascinating electronic and optical properties as a consequence of their dimensions and they may be easily synthesized from a wide range of materials. The dimensi…
An octanuclear supramolecular assembly comprising La ions in a square antiprismatic array is found in [La8L]. The eight nine-coordinate lanthanum centers are coordinated here by eight rigid C3-symmetric pyrazolone ligands L1 to give an extraordinary ring architecture (see picture).
Ten defined chiral centers are present in the [15]metallacrown-5 complex that is assembled in a one-step reaction from L-tyrosinehydroxamic acid, CuII, and GdIII. Nitrate ions bind selectively to this complex in a cavity of dimension 776 Å3, while chloride binds to the outer face (see picture).
Ein Monooxygenase-Mimetikum: Ein Cytochrom-P-450-Modell mit vier Cyclodextrin-Einheiten an einem Mangan-Porphyrin-Komplex kann mit katalytischem Turnover in eine nichtaktivierte C-H-Bindung ein Sauerstoffatom einschieben (siehe Bild). Die Hydroxylierung eines über zwei Bindungsstellen gebundenen Androstan-3,17-dioldie…
A mimic of monooxygenase enzymes: An artificial cytochrome P-450 with four cyclodextrins linked to a manganese/porphyrin complex can insert an oxygen atom into unactivated C−H bonds with catalytic turnovers (see picture). Hydroxylation of a doubly bound diester of androstane-3,17-diol at C-6 is possible; further oxida…
The controlled construction of a microporous/macroporous materials from diatomaceous earth and a high silica zeolite by a simple method is reported. The picture shows scanning electron microscopy images of the material at two scales (left and center) and the arrangement of the zeolite crystals precipitated onto it (ri…
Coupling agents in wood fiber and polymer composites (WFPC) play a very important role in improving the compatibility and adhesion between polar wood fibers and non-polar polymeric matrices. In this paper, we review coupling agents, pretrcatment, and mixing technology for wood fiber and polymer currently used in the m…
The aggregation of nanocrystals has long been believed to result in disordered solids. In his Perspective, Alivisatos discusses recent evidence that nanocrystals may also form oriented assemblies. He highlights the work by Banfield et al. in this issue, who show that such alignment can also occur in natural systems. T…
The radiation performance of a variety of complex oxides is predicted on the basis of a material's propensity to accommodate lattice point defects. The calculations indicate that a particular class of oxides possessing the fluorite crystal structure should accept radiation-induced defects into their lattices far more…