Materials Literature
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Poly(3-hydroxybutyrate) (PHB)-negative mutants of Bacillus megaterium were isolated following mutagenesis with N-methyl-N′-nitro-N-nitrosoguanidine. Different strategies were used for isolation, including ultracentrifugation through sucrose gradients and selection for resistance to allyl alcohol. The mutants were dete…
Distannoxane complexes catalyze the ring-opening polymerization of optically active β-butyrolactone (β-BL) to afford a high molecular weight poly(3-hydroxybutyrate). When 1-ethoxy-3-chlorotetrabutyldistannoxane was used as a catalyst (catalyst/(R)-β-BL = 1/8000 at 100 °C for 4 h), poly((R)-3-hydroxybutyrate) was obtai…
Parallele Schichten aus Fe‐ und O‐Atomen charakterisieren den Clusterkern des zehnkernigen Fe III ‐Komplexes 1 (dbm = Dibenzoylmethan), der durch kontrollierte Hydrolyse aus FeCl 3 entsteht. Die O‐Atome in 1 bilden dabei in Analogie zu denen in einigen Eisenoxiden und ‐hydroxiden eine kubisch dichteste Packung. Die sc…
The structure consists of layers of Ag(CN) 2 - ions arranged in such away that trigonal prisms of N atoms are formed. Each prism is occupied by an Eu 3+ ion, to which three H 2 O molecules coordinate and complete the tricapped trigonal geometry.
Polarized properties of both the singlet and triplet ground exciton states in the photoluminescence and transmission spectra of crystalline GaTe are explained based on the possible symmetry properties of the energy band edge of GaTe. Some experimental results about excited exciton states in GaTe are presented and disc…
Crystal structure of K 2 Co 2 (SO 4 ) 3 was determined at nine temperatures in the high-temperature cubic phase. In contrast to the early structural study, the split-atom calculation concludes that the SO 4 ion has a number of equilibrium arrangements. Mean-square atomic displacements become large with approaching the…
Spatial resolution of optically addressed spatial light modulators (OASLMs) is degraded by several different transfer processes in these devices. We have developed a general transient charge transport model to calculate and simulate the resolution limits of OASLMs due to the following charge spreading mechanisms durin…
During the growth phase of Alcaligenes eutrophus, it was observed that the concentrations of glucose and ammonium ions are inhibitory at a certain level, which affects the specific growth rate. Moreover, it has been established from previous work that (an) unidentified substance(s) inhibit(s) the growth at biomass con…
We have observed the unoccupied partial Pd 4d density of states in Cu-Pd alloys by bremsstrahlung isochromat spectroscopy (BIS). It shows the filling of the Pd 4d band upon alloying, which is consistent with the Pd ${\mathit{L}}_{\mathrm{III}}$ absorption spectroscopy measurements. We have also determined the total ch…
Addition of germanium to the Se–Te alloy causes structural changes which modify the band structure and hence the electrical properties of the Se–Te alloy. In the present work, electrical, optical, and structural properties of Se–Te–Ge have been studied. The activation energies calculated from the dc resistivity measur…
The considerable industrial interest in the qualitative and quantitative production of polyhydroxyalkanoates in microorganisms has led to the characterization of those synthesized in the nitrogen-fixing bacteria Azospirillum brasilense and Azotobacter paspali. In contrast to some other bacterial species, Azospirillum…
Neutron diffraction has been used to determine the location and concentration of C in Nd2Fe17 and in a Si substituted alloy. The results indicate that two carbide phases exist. One contains nearly three C atoms per formula unit, while the other has a much lower concentration. The high C phase contains C only on the 9e…
Large photoinduced absorption is observed in free-standing porous-silicon films in the spectral range from 1.1 to 2.5 eV by using a femtosecond pump-and-probe technique. The measured nonlinear transmission spectra have a very fast component with initial decay on the subpicosecond time scale. The spectral structure and…
Selected tensor property coefficients of the nonlinear optical crystal LiB3O5 are reported. The full set of pyroelectric, dielectric, and thermal expansion coefficients were measured as a function of temperature. The five independent piezoelectric coefficients, the full set of electromechanical coupling coefficients,…
Valerate and other short-chain, uneven-length fatty acids promoted the formation of the polyhydroxyalkanoate (PHA) copolymer poly(3-hydroxybutyrate-co-3-hydroxyvalerate) in Azotobacter vinelandii UWD growing in glucose medium. The uptake of valerate was inducible, being repressed by acetate but not by glucose. A likel…
Poly(hydroxyalkanoates) form biodegradable composites when blended with starch granules but the mechanical properties are poor. Unlike starch granules, thermoplastic starch is a flexible material that can be reprocessed at elevated temperatures. Mixing thermoplastic starch with poly(hydroxybutyrate-co-12%-hydroxyvaler…
The adsorption of Li on the Si(100) surface has been studied over a wide coverage range with high-resolution core-level spectroscopy. The dimer structure of the clean surface was preserved up to a coverage corresponding to \ensuremath{\Delta}\ensuremath{\varphi}=-1.8 eV. Above this coverage intermixing and silicide gr…
Ein kettensteifes molekulares Rückgrat mit hydrophilen und hydrophoben Substituenten zeichnet das makrocyclische Amphiphil 1 aus, das im Grammaßstab zugänglich ist. Wie die Kristallstrukturanalyse von 1 nach Umkristallisieren aus Pyridin zeigt, weisen die polaren Phenoxygruppen nach außen, und der Ring bildet einen hy…
In vitro preparation of long side chain poly(3-hydroxyalkanoate) artificial granule suspensions that mimic the "as biosynthesized" inclusions in vivo is reported. Elastomeric poly(3-hydroxyalkanoate) can be made into an aqueous suspension of noncrystalline, submicron-sized particles. Light-scattering measurements on t…
The first-principles orthogonalized linear combination of atomic orbitals method has been applied to calculate the electronic structures, total energies, and optical properties of four boron-rich compounds: ${\mathrm{B}}_{12}$${\mathrm{As}}_{2}$, ${\mathrm{B}}_{12}$${\mathrm{P}}_{2}$, ${\mathrm{B}}_{11}$C(CBC) (or ${\…