Materials Literature
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Summary: A heavy-metal-accumulating Citrobacter sp. has been used for the treatment of metal-laden industrial wastes. Metal uptake is mediated via a cell-bound phosphatase that liberates inorganic phosphate which precipitates with heavy metals as cell-bound metal phosphate. A phosphatase-deficient mutant accumulated l…
It is shown that the magnon spectrum of magnetically ordered crystals can be calculated using a frozen magnon scheme and spin density functional theory in the local approximation. Ab initio calculated magnon spectra for Fe and Ni are presented. Kohn anomalies are predicted for the magnon spectrum of Fe. Considering th…
We have measured the Flory−Huggins interaction parameter (χ) for blends of polystyrene (PS) and poly(4-vinylpyridine) (P4VP) by three different methods. First, we measured the micelle spacings in microphase-separated films of PS−P4VP diblock copolymers by secondary ion mass spectrometry and atomic force microscopy. Se…
Five layered silicates in which the octahedral sheet contained differing amounts of Al, Mg, Fe, and Li were acid leached using acid concentrations and treatment temperatures selected to produce materials in which the octahedral sheet was depopulated in a controlled, stepwise (yet comparable) manner. SAz-1 and JP are d…
The synthesis of mesoporous silica sell‐shapes , with spiral and gyroid forms and ornate surface designs (see the inside front cover for examples), is described. High‐resolutioin SEM, TEM, and AFM were used to establish the spatial relationship between the bulk and surface mesosstructure and the overall morphpology of…
The first time-resolved infrared difference spectra for metal-to-ligand charge transfer (MLCT) excited states in the fingerprint region from 1400 to 1625 cm -1 are reported for [Ru(bpy) 3 ] 2+ * and [Re(bpy)(CO) 3 (4-Etpy)] + * in CD 3 CN at 298 K (bpy is 2,2‘-bipyridine; 4-Etpy is 4-ethylpyridine). The spectra are as…
A hybrid electrochemical/chemical (E/C) method is employed to synthesize epitaxially oriented CdS nanocrystallites size selectively on graphite surfaces. The E/C synthesis involves three steps: (1) cadmium metal nanocrystals (NCs) are electrochemically deposited on the graphite basal plane surface; (2) cadmium NCs are…
The effect of particle solubility and the dissolution rate on agglomeration was studied by drying silica and titania particles from aqueous slurries with pH values in the range of 2–12. The agglomerate strength and strength distribution were measured by a calibrated ultrasonic force, and the strength increased as the…
Novel semicrystalline, poly(vinyl alcohol) (PVA)-based phase erosion systems were developed. The rate of drug release from these systems is controlled by the rate of crystal dissolution. PVA devices loaded with metronidazole were exposed to temperatures ranging from 90 to 120 C for times of 10-90 min to obtain samples…
We report a scheme for the II−VI chalcogenide sol−gel synthesis, using cadmium sulfide as a model system. Highly concentrated sols are obtained by surface complexation of CdS nanocrystals with 4-fluorophenylthiol. Controlled aggregation and gelation is then achieved by a progressive decomplexation of the particles via…
Films of AOT-capped (AOT = dioctyl sulfosuccinate) lead sulfide nanoparticles (Q-PbS) were prepared by incorporation into a self-assembled monolayer of hexanethiol on Au. The Q-PbS particles showed either cathodic or anodic photocurrents, depending on the existence of a hole scavenger or an electron scavenger in the c…
Two high resolution crystal structures of cytosolic aspartate aminotransferase from pig heart provide additional insights into the stereochemical mechanism for ligand-induced conformational changes in this enzyme. Structures of the homodimeric native structure and its complex with the substrate analog 2-methylaspartat…
The observation of luminescence from the state in under vacuum ultraviolet excitation is reported and discussed. The photon cascade emission consists of the and transitions. The efficient multiphonon nonradiative relaxation is responsible for the absence of luminescence in .
The relation between rheology and the time dependent morphology of a phase-separating binary blend of polystyrene and poly(vinyl methyl ether) was investigated by heating a sample from the single-phase (at 90 °C) into the two-phase regime (at 124 °C, 16 K above the LCST) and maintaining its temperature there while mea…
The rate-dependent deformations of the titanium alloy Ti-6A1-4V are investigated using a combination of standard testing machines and compression and torsional Kolsky bars. Both homogeneous and localized deformations of both non-porous (‘fully dense’) and porous (7.6% porosity) versions of the alloy are studied. The m…
Langmuir−Blodgett (LB) films of a series of divalent metal octadecylphosphonates have been prepared and characterized. The films are each shown to be LB analogs of known solid-state metal phosphonates possessing 2-dimensional ionic−covalent metal phosphonate layers. The metal phosphonate layers crystallize during the…
Abstract The mineralogy of bulk and rhizosphere soil materials was compared to assess the effect of roots on mineral weathering in a Podzol supporting a homogeneous Norway spruce [ Picea abies (L.) Karst] stand. Six horizons were sampled in two profiles at the Skogaby site in southwestern Sweden. The soil adhering to…
Pyrazinamide (pza) and 2-mercaptopyridine (2-MPy) are shown to form Ag colloid−adsorbate films at the interface between an aqueous Ag colloid and a solution of an adsorbate in dichloromethane. By contrast, under the same conditions, 4-mercaptopyridine (4-MPy) forms Ag organosol aggregates by the interface transfer of…
By applying the Maxwell Garnett model to gold nanoparticles in water we deduce a value of Im χi(3)=1.1×10-7 esu for the imaginary part of the cubic susceptibility for gold corresponding to a Fermi smearing mechanism. We also demonstrate a sign reversal in the nonlinear absorption for gold particles in 1, 1′, 3, 3, 3′,…
The structural characterization of samples of syndiotactic polypropylene (s-PP) isothermally crystallized from the melt is presented. Form I of s-PP, with variable amount of disorder, is obtained at every crystallization temperature. The limit ordered modification, characterized by a fully antichiral packing along bot…