Materials Literature
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Peptide-amphiphiles with collagen-model head groups and dialkyl chain tails have been synthesized and shown to self-assemble into highly ordered polyPro II like triple-helical structures when dissolved in aqueous subphases. Evidence for this self-assembly process has been obtained from (a) compression of stable peptid…
The local structure of dragline silk from the spider Nephila madagascariensis is investigated by solid-state nuclear magnetic resonance. Two-dimensional (2D) spin-diffusion experiments show that the alanine-rich domains of the protein form β-sheet structures in agreement with one-dimensional NMR results from a differe…
Aqueous acetone extracts of shoots of Eurasian watermilfoil (Myriophyllum spicatum) exhibit a strong inhibitory action against various coccoid and filamentous cyanobacteria and to a slightly less extent against chlorophytes and diatoms. Bioassay-directed fractionation led to the isolation of a hydrolysable polyphenol,…
The hydroxylation of proline residues in collagen enhances the stability of the collagen triple helix. Previous X-ray diffraction analyses had demonstrated that the presence of an electron-withdrawing substituent on the pyrrolidine ring of proline residues has significant structural consequences [Panasik, N., Jr.; Ebe…
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorSilsesquioxanes as Synthetic Platforms. Thermally Curable and Photocurable Inorganic/Organic HybridsAlan Sellinger and Richard M. LaineView Author Information Department of Materials Science and Engineering, Department of Chemistry, and…
The iron(II) spin state of Fe(C5H5N)2Ni(CN)4 changes from paramagnetic to diamagnetic when the temperature is lowered, while that of Fe(NH3)2Ni(CN)4·2C6H6 does not.
DNA sequences were isolated by in vitro selection for binding to N-methylmesoporphyrin IX (NMM), a molecule that behaves as a stable transition-state analogue for porphyrin chelatases. Clones approximately 280 and approximately 120 nucleotides long were obtained, which bound to NMM with sub-micromolar affinity but bou…
Inverted unimol. dendritic micelles were prepd. by modification of end groups of poly(propyleneimine) dendrimers with hydrophobic alkyl chains. The dendritic character and micellar structure of the products were studied
Aqueous suspensions of two smectite clays, natural bentonite and synthetic laponite B, were prepared at concentrations ranging from 0.01 to 0.1 g/cm 3 . Viewed at rest between crossed polarizers, concentrated gel suspensions (> 0.024 g/cm 3 for bentonite and > 0.020 g/cm 3 for laponite B) show optical birefringence wh…
At low relative humidity (RH), an edible wheat gluten film presents very low oxygen and carbon dioxide permeabilities [1.24 and 7.4 amol/(Pa m s), respectively, at 25 °C]. For higher than 60% RH, O 2 and CO 2 permeabilities increase exponentially [to 1290 and 36 700 amol/(Pa m s), respectively, at 95% RH], presumably…
Polyaniline can be inserted in V 2 O 5 · n H 2 O xerogel by in situ oxidative polymerization/intercalation of aniline or anilinium in air. The reaction is facile and topotactic, forming polyaniline as the emeraldine salt. The interlayer separation (5.6 Å) is consistent with a monolayer of polymer chains in the V 2 O 5…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTNanostructured Molybdenum Carbide: Sonochemical Synthesis and Catalytic PropertiesTaeghwan Hyeon, Mingming Fang, and Kenneth S. SuslickView Author Information School of Chemical Sciences University of Illinois at Urbana−Champaign 505 S. Mathews Avenue, Urbana, Illinois…
Chitosan films were acylated under heterogeneous conditions in methanol with acetic and hexanoic anhydrides and characterized by proton nuclear magnetic resonance, elemental analysis, and multiple internal reflective Fourier transform infrared spectroscopy. The disappearance of the NH 2 vibrational band at 1590 cm -1,…
The preparation, characterization, and luminescence of yttrium‐based phosphors such as europium activated yttrium oxide (red) and terbium activated yttrium aluminate (green) by sol‐gel processes is presented. The sols of yttrium hydroxide were synthesized by various routes. It was found that the sols obtained through…
First hyperpolarizabilities of a large number of push−pull substituted conjugated systems with heteroaromatic spacers have been calculated. The static, nonresonant components were computed at the ab initio level (4-31G basis) using the coupled perturbed Hartree−Fock approach and at the AM1 level employing the finite f…
Ferroelectric composites are now an established alternative to conventional ferroelectric ceramic materials and to the more recently discovered ferroelectric polymers. These materials due to their unique blending of polymetric properties of mechanical flexibility, formability and low cost with high electro-active prop…
A novel class of catalysts for alkane oxidation with molecular oxygen was examined. N-Hydroxyphthalimide (NHPI) combined with Co(acac)(n)() (n = 2 or 3) was found to be an efficient catalytic system for the aerobic oxidation of cycloalkanes and alkylbenzenes under mild conditions. Cycloalkanes were successfully oxidiz…
The deposition of cerium‐rich films on copper under cathodic polarization was studied as a model system for understanding the mechanism of corrosion inhibition of copper‐containing aluminum alloys. Deposition was also studied on gold and iron for comparison with copper. Inhibition of corrosion of the aluminum alloys i…
An FTIR and quadrupole mass spectroscopic study of CO adsorption and oxidation with 16 O 2 and 18 O 2 is presented together with coadsorption experiments of CO and water on gold supported on ZnO and TiO 2 . The experimental results are closely related to those presented in the parallel paper on copper catalysts suppor…
Circumstances leading to twisting crystallographic orientation in banded polymer spherulites are analyzed, both from the standpoint of qualitative morphology and of more quantitative measurement and calculation. Particular attention is paid to linear polyethylene, for which the most extensive information is available,…