Materials Literature
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A high-mobility (9000 cm 2 /V·s) semiconducting single-walled nanotube transistor is used to construct a nonvolatile charge-storage memory element operating at room temperature. Charges are stored by application of a few volts across the silicon dioxide dielectric between nanotube and silicon substrate, and detected b…
Abstract The milling behavior of brominated isobutylene‐co‐paramethylstyrene (BIMS), ethylene propylene diene terpolymer (EPDM), and their blends was investigated over a range of temperatures and friction ratios using the continuous milling operation. At 30 °C, BIMS forms a loose nervy appearance and, as the temperatu…
Human lactoferrin is an iron-binding protein with a bilobal structure. Each lobe contains a high-affinity binding site for a single Fe(3+) ion and an associated CO(3)(2-) ion. Although iron binds very tightly, it can be released at low pH, with an accompanying conformational change in which the two domains move apart.…
Abstract Solvent transport in poly(ethylene terephthalate) (PET) and related phase transformation were investigated. The data of mass sorption were analyzed according to Harmon's model for Case I (Fickian), Case II (swelling), and anomalous transport. This transport process in PET is accompanied by the induced crystal…
SSD-4, the fourth version of the NIST Surface Structure Database, has appeared in early 2002 as a significant upgrade to both the database and graphics software; it now also includes nearly 1300 structures published through the end of 2000. SSD is an interactive PC-based database of critically selected surface structu…
A series of experiments performed at Cu Kalpha wavelength on in-house X-ray equipment are presented which investigate two possibilities for enhancing the experimental phasing signal by means of (i) triiodide/iodide soaks using KI/I(2) and (ii) combinations of counter-ions introduced using the short cryosoak method. Tr…
FtsH is a membrane-anchored ATP-dependent protease that degrades misfolded or misassembled membrane proteins as well as a subset of cytoplasmic regulatory proteins. It belongs to the family of AAA(+) ATPases with roles in diverse cellular processes. The ATPase domain of FtsH from Escherichia coli has been crystallized…
Abstract Influences of chemical oxidation polymerization conditions on the yields of polyaniline powder were investigated. These chemical oxidation polymerization conditions included polymerization time, concentration of HNO 3 , mol ratio of ammonium persulfate/aniline (APS/AN), and polymerization temperature. If poly…
S pili are sialic acid binding hair-like appendages expressed by pathogenic strains of Escherichia coli. The presence of S pili has been implicated as a virulence factor in both urinary-tract infections and new-born meningitis. Assembly of S pili proceeds via the ubiquitous chaperone/usher pathway. Previously, structu…
Abstract Effects of polymerization temperature, conversions, and nonionic surfactant on the particle properties of suspension poly(vinyl chloride) (PVC) resins were investigated. It was shown that polymerization temperature has no significant influences on the mean particle size of PVC resin, and that the cold plastic…
One reason for introducing a gel in the crystallization medium of proteins is its ability to reduce convection in solution. This can lead to better nucleation and growth conditions, and to crystals having enhanced diffraction properties. We report here the X-ray characterization at room temperature of high-quality cry…
We use molecular dynamics (MD) simulations to investigate the modification of the dynamic and static properties of liquid toluene when confined in cylindrical mesopores a few molecular diameters across. Due to the strong influence of the substrate on the dynamics of the confined liquid, we choose a procedure where no…
The details of the electronic and crystal structure, the nature of the interatomic bonding and the phase stability of three modifications of klockmannite, CuSe, are analysed using first principles modeling. The hexagonal modification of CuSe is predicted to be less stable than the orthorhombic phase under pressure. Th…
Protein crystallization has gained a new strategic and commercial relevance in the next phase of the genome projects, in which X-ray crystallography will play a major role. Considerable advances have been made in the automation of protein preparation and also in the X-ray analysis and bioinformatics stages once diffra…
The information in the Inorganic Crystal Structure Database (ICSD) can be used to determine the structures of new compounds by analogy; this database is thus a useful tool for practical problem solving. A model for the structure of (NH(4))Fe(CO(3))(OH)(2) [Cmcm, a = 6.6154 (6), b = 12.0639 (10), c = 6.0263 (5) A, Z =…
Abstract The anionic ring‐opening polymerizations of ( R , S )‐β‐butyrolactone and ( S )‐β‐butyrolactone initiated with tetrabutylammonium salts of carboxylic acids as initiators were investigated. Poly[( R , S )‐3‐hydroxybutyrate] and poly[( R )‐3‐hydroxybutyrate], with relatively high molecular weights (170,000 and…
Abstract This article reviews recent topics in the controlled synthesis of polycarbonates and polylactones with small polydispersity indices by activated monomer cationic ring‐opening polymerizations, especially with new initiator systems, such as alcohol/protonic acid and boron alkoxide/protonic acid. © 2002 Wiley Pe…
First-principles calculations based on spin-polarized density functional theory (DFT) and the generalized gradient approximation (GGA) have been used to study the adsorption of CO and NO molecules on the rutile (TiO 2 ) (110) surface in the presence of oxygen vacancy sites. The calculations employ slab geometry and pe…
A high-pressure Raman study of microcrystalline tungsten oxide was performed in the 0.1 MPa-30 GPa pressure range under hydrostatic and non-hydrostatic conditions. Two phase transitions are evidenced; they take place below 0.1 GPa and at about 22 GPa and are of first order. Two spectral anomalies are observed at about…
We report a detailed study of the optical reflectance in sputter-deposited, nanocrystalline silver thin films in order to understand the marked changes in color that occur with decreasing particle size. In particular, samples with an average particle size in the 20 to 35 nm range are golden yellow, while those with a…