Materials Literature
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Metabolites associated with the poly(3-hydroxybutyrate) (PHB) biosynthetic pathway in Alcaligenes eutrophus were measured to gain an insight into the regulation of PHB synthesis in vivo. Alcaligenes eutrophus was grown in carbon-limited chemostat culture to provide bacteria producing negligible PHB, and in nitrogen-li…
The problem of deriving from microscopic theory a Ginzburg-Landau free-energy functional to describe the Peierls or charge-density-wave transition in quasi-one-dimensional materials is considered. Particular attention is given to how the thermal lattice motion affects the electronic states. Near the transition tempera…
Novel functional poly(β-hydroxyalkanoates), PHAs, with hyperpolarizable side groups were prepared. Pseudomonas oleovorans ATCC 29347 and Pseudomonas putida KT 2442 were selected as biocatalysts. These organisms were first grown on citrate (40 mM) before polymer formation was studied in a second stage. The carbon sourc…
The isolation of poly(3-hydroxyoctanoic acid)- and poly(6-hydroxyhexanoic acid)-degrading bacteria yielded 28 strains with abilities to degrade various polymers. The most versatile strains hydrolyzed five different polyesters comprising short chain length and medium chain length poly(hydroxyalkanoates). The new isolat…
Using a recently developed method, we show here that solvent effects on the first molecular hyperpolarizabilities of push-pull polyenes can be predicted by evaluation of the relaxation contribution βr to the hyperpolarizability from vibrational infrared and Raman intensities and vibrational frequencies. The molecules…
In 1990, Liu and Cohen presented a pseudopotential study of the structural and electronic properties of β- C 3 N 4 , a hypothetical compound. The calculated properties of β- C 3 N 4 , including bulk modulus and velocity of sound, were found to be comparable to that of diamond suggesting high values for hardness and fo…
We present an analysis of the extensive photolysis of an adsorbate resulting from adsorbate core-level excitation. The system studied was SiF4 adsorbed on Ge(100) at 30 K. Photolysis fragments and molecular species (identified with Si 2p soft x-ray photoemission spectroscopy) were measured as a function of monochromat…
The hydrothermal synthesis and single-crystal structure of potassium vanadium(V) selenite, K(VO 2 ) 3 (SeO 3 ) 2 , are reported. K(VO 2 ) 3 (SeO 3 ) 2 is a layered phase based on a hexagonal tungsten-oxide-like array of corner-sharing VO 6 octahedra capped by Se atoms, and is isostructural with NH 4 (VO 2 ) 3 (SeO 3 )…
Hydrogenophaga pseudoflava (formerly Pseudomonas pseudoflava) was able to accumulate a large amount of copolyesters when grown on mixed substrates of glucose and lactones in a batch fermentation. Lactones such as γ-butyrolactone, γ-valerolactone, and higher analogues generally did not support cell growth when used as…
Cyclic oligo(3-hydroxybutyrate), oligo(3-HB), was synthesized and purified, resulting in oligolides that contained three to seven (R)-3-hydroxybutyrate units (triolides up to heptolides). In addition, linear 3-HB octamers obtained as either tert-butyl or methyl esters were substituted with different end groups at the…
The vacancy model for the electronic structure in silicon of substitutional transition elements near the end of the 3d, 4d, and 5d series is described and a simplified theoretical treatment for their paramagnetic properties is presented. It is concluded that the complete set of such impurities for which experimental i…
The increasing commercial importance of polyhydroxyalkanoates calls for the development of new, more efficient production processes. This can only be achieved by considering the kinetics of polyhydroxyalkanoate accumulation in fermentors, but efforts in this area have been few. In a 10-L fed-batch fermentor, Alcaligen…
SrS:Ce is an intensively investigated phosphor due to its blue-green electroluminescence, which shows efficient blue emission after filtering. Recently reported devices based on this material have demonstrated a luminous efficiency of 1.6 lm/W. The luminescence properties of SrS:Ce,X (X=Na or Cl) have been studied on…
Spherical quantum-dot--quantum-well nanocrystallites, with internal radial quantum-well band profiles, can now be fabricated. Pair states in these nanoheterostructures are determined by electron-hole attraction, global confinement in the dot, and local confinement within the well. Configuration-interaction calculation…
Interrelationship among electronic structures of α -(ET) 2 I 3 , (ET) 2 MHg(SCN) 4 and κ -(ET) 2 X is studied theoretically. The effects of on-site Coulomb interaction are investigated at absolute zero within the Hartree-Fock approximation. If Coulomb interaction exceeds some critical value, various kinds of antiferro…
Microstructural changes that occur in a GeSbTe film during repetitious overwriting in phase-change optical recording were investigated. The GeSbTe active layer was melted by a focused laser diode (LD) beam during each overwriting process over amorphous mark formation. The repetitious solidification and liquefaction pr…
The miscibility, morphology, and biodegradability of a binary blend of bacterial poly((R)-3-hydroxybutyric acid)(P((R)-3HB);Mn = 300,000) with atactic poly((R,S)-lactic acid)(P((R,S)-LA);Mn = 9,000) were studied by means of differential scanning calorimetry, optical microscopy, scanning electron microscopy, and hydrol…
X-ray diffraction and electrical resistance have been measured for amorphous and crystalline Te 1- x Se x mixtures (0≤ x ≤1) under high pressure up to 30 GPa, and four high pressure phases of Te-Se mixtures have been observed: a monoclinic phase with 6 atoms per unit cell (M-I phase); a monoclinic phase with 4 atoms p…
A number of Escherichia coli strains including K12, B, W, XL1-Blue, DH5 alpha, HB101, JM109, and C600 were transformed with the stable high-copy-number plasmid pSYL105 containing the Alcaligenes eutrophus polyhydroxyalkanoic acid biosynthesis genes, and were subsequently compared for their ability to synthesize and ac…
Based on first-principles total-energy calculations we have determined the chemical identity and adsorption site of the adatoms observed recently in scanning tunneling microscopy on the SiC(0001)\ensuremath{\surd}3\ifmmode\times\else\texttimes\fi{}\ensuremath{\surd}3 surface. The calculations indicate that Si adatoms…