Materials Literature
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A new universal inelastic mean free pathlength (IMFP)-predictive equation (the G1 equation) has been formulated for use in the analytical electron spectroscopies XPS and AES which essentially states that the IMFP of an electron traversing matter is inversely proportional to the atomic density. The equation is based on…
The first examples of organic polymer-layered silicic acid nanocomposites have been prepared by formation of a cured epoxy polymer network in the presence of organo cation-exchange forms of magadite. The transparency of the exfoliated magadiite hybrid is an especially notable property.
The type and concentration of hydroxy groups in MCM-41 as a function of the Si:Al ratio have been investigated and compared with amorphous Si/Al oxide. Three hydroxy groups at 3745, 3715 and 3530 cm–1 were observed in the IR spectra of siliceous MCM-41. For Al-containing samples the intensity of the bands at 3715 and…
Template-assembled collagen-based polypeptides KTA-[Gly-(Gly-Pro-Hyp) n -NH 2 ] 3 ( n = 1, 3, 5, 6; KTA is cis, cis -1,3,5-trimethylcyclohexane-1,3,5-tricarboxylic acid, also known as the Kemp triacid) and acetyl-terminated single-chain collagen-based analogs Ac-(Gly-Pro-Hyp) n -NH 2 ( n = 1, 3, 5, 6, 9) were synthesi…
The crystal structure of holo D-glyceraldehyde-3-phosphate dehydrogenase (GAPDH) from the extreme thermophile Thermus aquaticus has been solved at 2.5 Angstroms resolution. To study the determinants of thermostability, we compare our structure to four other GAPDHs. Salt links, hydrogen bonds, buried surface area, pack…
A wide range of important crystalline solids cannot be prepared in the form of single crystals of suitable size and quality for structural characterization by conventional single-crystal X-ray diffraction methods. The development of techniques for crystal structure determination from powder diffraction data is clearly…
Conditions that promote renaturation of an unfolded protein also promote protein aggregation, in many cases, because these competing intramolecular and intermolecular processes are driven by similar networks of noncovalent interactions. The GroEL/GroES system and related biological chaperones facilitate the renaturati…
A combinatorial library of catalyst candidates, each consisting of a different metal element supported on γ-alumina, is screened for hydrogen oxidation catalytic activity. Heat liberated on the surface of active catalysts by the catalyzed reaction is detected by noninvasive IR thermography. A 16-candidate library iden…
The reaction products from the radically initiated grafting of specifically 13 C-enriched maleic anhydride ([2,3- 13 C 2 ]MA) onto polyethene, isotactic polypropene and ethene-propene copolymers in the melt and in solution are investigated using noise-decoupled and 1D inadequate 13 C NMR spectroscopy. The sites of att…
By diminishing the energy barrier between SCA* and SC*, antiferroelectricity has become thresholdless in a three-component mixture. It shows V-shaped switching, realizing attractive display characteristics: extremely wide viewing angle with very large contrast ratio, high speed response and ideal analogue grey scale w…
A statistical survey of the torsion angles, bond angles, and bond lengths in the sugar and phosphate groups of well-refined mononucleoside, mononucleotide, dinucleoside monophosphate, and trinucleoside diphosphate crystal structures contained in the Cambridge Structural Database and the Nucleic Acid Database is report…
There is a wealth of information on the mineral and matrix components in bones and teeth, in the exoskeletons of invertebrates, and in dystrophic calcific deposits. This information includes detailed characterization of their physical and chemical composition and details on the gene localization and regulation of gene…
Thin films of poly[styrene- block -(2-vinylpyridine)] with equally long blocks were prepared by casting micellar toluene solutions on a mica or carbon substrate. The structure of the films was studied by scanning force microscopy and transmission electron microscopy. Structural variations were observed depending on th…
The utility of employing a variable duty cycle pulsed plasma polymerization technique to control film chemistry during plasma depositions is examined using allyl alcohol as monomer gas. Large scale progressive variations in film composition are observed with sequential changes in the plasma duty cycles employed, all o…
The often observed decrease in relative permittivity (ε‘) and refractive index ( n ) that accompanies fluorine substitution is the result of several effects. Fluorine replacement for hydrogen is known to decrease local electronic polarization and is thought to frequently increase fractional free volume. Both of these…
A new family of molecular squares containing ReI polypyridyl and polypyrazyl centers has been synthesized at quantitative yields via a self-assembly method. Ambient-temperature photophysical studies reveal that two of the squares (4,4‘-bipyridine- and pyrazine-bridged species) readily luminesce in solution from relati…
The effects of applied electric fields and solvent polarity on the linear and nonlinear optical (NLO) properties of three prototypical merocyanine (donor−conjugated pathway−acceptor) chromophores of differing architectural types are analyzed using semiempirical INDO/1 calculations in the presence of imposed static ele…
Phthalocyanines and related compounds can self-assemble into columnar structures in the solid and liquid crystalline state, in Langmuir–Blodgett films and in solution. This paper presents an overview of supramolecular architectures that have been constructed using several phthalocyanine and porphyrazine building block…
The backbone dihedral angle φ in polypeptides is characterized by four different J couplings: 3 J H N H α, 3 J H N C ‘, 3 J H N C β, and 3 J H α C ‘ . E.COSY and quantitative J correlation techniques have been used to measure these couplings in the protein human ubiquitin, uniformly enriched in 13 C and 15 N. Assuming…
We have demonstrated the synthesis of PbS nanoclusters within the microphase-separated films of diblock copolymers containing carboxylic acid units on one of the blocks. Lead was selectively sequestered into the acid containing domains by treating the polymer films with tetraethyllead, and PbS was formed by subsequent…