Materials Literature
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The effect of glassy‐phase chemistry, using Y 3 Al 5 O 12 (YAG) and SiO 2 as sintering additives, on the microstructure and mechanical properties of liquid‐phase‐sintered, and subsequently annealed, α‐SiC materials was investigated. The microstructural development of annealed materials was insensitive to changes in gl…
It was shown recently that recombinant Escherichia coli, defective in the beta-oxidation cycle and harboring a medium-chain-length (MCL) poly(3-hydroxyalkanoate) (PHA) polymerase-encoding gene of Pseudomonas, is able to produce MCL PHA from fatty acids but not from sugars or gluconate (S. Langenbach, B. H. A. Rehm, an…
The lysine residue binding with the cofactor pyridoxal 5'-phosphate (PLP) plays an important role in catalysis, such as in the transaldimination and abstraction of alpha-hydrogen from a substrate amino acid in PLP-dependent enzymes. We studied the role of Lys39 of alanine racemase (EC 5.1.1.1) from Bacillus stearother…
Thin films of carbon have been deposited on n-type single-crystal silicon and quartz substrates by simple ion beam sputtering of camphoric carbon, obtained from camphor, a natural source. Optical absorption coefficients of 10 4 –10 5 cm -1 have been obtained for the as-deposited and annealed films and the absorption c…
Scanning force microscopy images of thiol-end-functionalized polystyrene monolayers, end-grafted to gold substrates from good solvent, showed two structural regimes in bad-solvent conditions. At low and moderate grafting densities the experimental results agree with the scaling arguments and can be situated correctly…
Highly ordered anodic porous alumina was used as a mask for a reactive beam etching (RBE) to transform the nanochannel pattern into III-V semiconductors. The alumina mask showed high tolerance to RBE using a Br 2 /N 2 mixed gas system. GaAs and InP nanohole arrays with a high aspect ratio and with diameter uniformity…
Silicon nitride (Si 3 N 4 ) and SiAlONs can be self‐toughened through the growth of elongated β‐Si 3 N 4 /β‐SiAlON grains in sintering. α‐SiAlONs usually retain an equiaxed grain morphology and have a higher hardness but lower toughness than β‐SiAlONs. The present work has demonstrated that elongated alpha‐SiAlON grai…
In order to impart barrier properties against microorganisms and blood to 100% cotton fabrics and 55/45% woodpulp/polyester spunlaced nonwoven fabrics, samples are treated with chitosan and fluoropolymers using the pad-dry-cure and pad-cure meth ods, respectively. Antimicrobial activity of the samples is analyzed quan…
In the framework of recently introduced frustrated lattice gas models, we study the out-of-equilibrium dynamical processes during the compaction in granular media. We find irreversible-reversible cycles in agreement with recent experimental observations, along which we can individuate an equivalent ``glass transition,…
The synthesis, reactivity and full characterization of a series of meso-tetraalkyl porphyrins and metalloporphyrins with R ≡ n-butyl (6), 2-methyl-propyl (7), isopropyl (8), l-ethyl-propyl (10) and tert-butyl (11) groups are reported. Derivatives of the last of these show considerably bathochromically shifted absorpti…
The capitate and rectangular demes of the freshwater epipelic diatom Sellaphora pupula (Kütz.) Mereschk. are dioecious, the first such report for any freshwater diatom. Sexual differentiation, which is probably determined genetically, involves recognition at the cell surface as well as differences in gamete behavior (…
The continuous structural transformation of tetragonal analcime (Na 15.87 Al 15.20 Si 32.64 O 96 ·16.3H 2 O) upon dehydration was studied, using Rietveld structure analysis of temperature- resolved powder diffraction data collected using synchrotron radiation. The variation of the a-c axis length difference and normal…
The mechanical response of a smectic-A liquid-crystalline side-chain polymer network with macroscopically ordered layers (smectic-A liquid single crystal elastomer) to extensive stress applied parallel to the layer normal is described. By stress-strain measurements a characteristic threshold strain of about 3% is obse…
The bacterial outer membrane proteins OmpA and OmpX were modified in such a manner that they yielded bulky crystals diffracting X-rays isotropically beyond 2 A resolution and permitting detailed structural analyses. The procedure involved semi-directed mutagenesis, mass production into inclusion bodies, and (re)natura…
Endogenous protein kinase inhibitors are essential for a wide range of physiological functions. These endogenous inhibitors may mimic peptide substrates as in the case of the heat-stable protein kinase inhibitor (PKI), or they may mimic nucleotide triphosphates. Natural product inhibitors, endogenous to the unique org…
The attempt to synthesize a Pb(Zn 1/3 Nb 2/3 )O 3 (PZN) powder of perovskite structure via both traditional ceramic and chemistry‐based novel processing routes over the last three decades has failed. Difficult‐to‐synthesize nanocrystallite PZN powders have, for the first time, been successfully prepared via a mechanoc…
Surface immobilized polyethylene oxide (PEO) has been shown to efficiently reduce protein adsorption and cellular adhesion, resulting in a biologically passive surface. To explore the in vitro effects of surface immobilized PEO on the human inflammatory cells, macrophages, and foreign body giant cells (FBGCs), we deve…
Nano-engineering of ceramic materials is investigated using block copolymers obtained from poly(isoprene- b-ethyleneoxide). The dimensions of these “hairy”, nano-sized products can be tuned by adding varying amounts of two metal alkoxides to give rise to objects of different shapes. The Figure shows a TEM image of cyl…
Heteroepitaxial diamond films with highly improved alignment have been realized by using the layer sequence diamond/Ir/SrTiO3(001). In a first step, epitaxial iridium films with a misorientation <0.2° have been deposited on polished SrTiO3(001) surfaces by electron-beam evaporation. Using the bias-enhanced nucl…
A thermodynamic theory is used to calculate the dielectric properties of epitaxial thin films grown on cubic substrates imposing biaxial tension on the film prototypic cubic state. For such “tensile” substrates, the theory shows that, in a conventional plate–capacitor setup, the films should display only a monotonic v…