Nucleation and growth of epitaxial metal-oxide films based on polymer-assisted deposition.

Polymer-assisted deposition (PAD) is one of the chemical solution deposition methods which have been successfully used to grow films, form coatings, and synthesize nanostructured materials. In comparison with other conventional solution-based deposition techniques, PAD differs in its use of water-soluble polymers in the solution that prevent the metal ions from unwanted chemical reactions and keep the solution stable. Furthermore, filtration to remove non-coordinated cations and anions in the PAD process ensures well controlled nucleation, which enables the growth of high quality epitaxial films with desired structural and physical properties.

Encapsulation of the Be(II) cation: spectroscopic and computational study.

The structures of a series of tetracoordinate beryllium(II) complexes with ligands derived from tertiary-substituted amines have been computationally modeled and their (9)Be magnetic shielding values determined using the gauge-including atomic orbital (GIAO) method at the 6-311++g(2d,p) level. A good correlation was observed between calculated (9)Be NMR chemical shifts when compared to experimental values in polar protic solvents, less so for the values recorded in polar aprotic solvents. A number of alternative complex structures were modeled, resulting in an improvement in experimental versus computational (9)Be NMR chemical shifts, suggesting that in some cases full encapsulation on the beryllium atom was not occurring.

Effect of spin-orbit coupling on the actinide dioxides AnO2 (An=Th, Pa, U, Np, Pu, and Am): a screened hybrid density functional study.

We present a systematic comparison of the lattice structures, electronic density of states, and band gaps of actinide dioxides, AnO(2) (An=Th, Pa, U, Np, Pu, and Am) predicted by the Heyd-Scuseria-Ernzerhof screened hybrid density functional (HSE) with the self-consistent inclusion of spin-orbit coupling (SOC). The computed HSE lattice constants and band gaps of AnO(2) are in consistently good agreement with the available experimental data across the series, and differ little from earlier HSE results without SOC. ThO(2) is a simple band insulator (f(0)), while PaO(2), UO(2), and NpO(2) are predicted to be Mott insulators.

Polymer-assisted-deposition: a chemical solution route for a wide range of materials.

In this tutorial article, the recent development of polymer assisted deposition (PAD) for the growth of a wide range of materials, in particular in thin films, is reviewed. Specifically, we describe the unique chemistry and processes of PAD for the deposition of metals, metal-oxides, metal-nitrides, metal-carbides, and their derived composites. Many examples are given not only to illustrate the powerfulness of PAD for high quality coatings, but also to give readers an opportunity to evaluate this technique for specific applications.

Aligned carbon nanotubes sandwiched in epitaxial NbC film for enhanced superconductivity.

Highly aligned carbon nanotube (CNT) ribbons were sandwiched in epitaxial superconducting NbC films by a chemical solution deposition method. The incorporation of aligned long CNTs into NbC film enhances the normal-state conductivity and improves the superconducting properties of the assembly.

Epitaxial superconducting δ-MoN films grown by a chemical solution method.

The synthesis of pure δ-MoN with desired superconducting properties usually requires extreme conditions, such as high temperature and high pressure, which hinders its fundamental studies and applications. Herein, by using a chemical solution method, epitaxial δ-MoN thin films have been grown on c-cut Al(2)O(3) substrates at a temperature lower than 900 °C and an ambient pressure. The films are phase pure and show a T(c) of 13.

Highly aligned carbon nanotube forests coated by superconducting NbC.

The formation of carbon nanotube and superconductor composites makes it possible to produce new and/or improved functionalities that the individual material does not possess. Here we show that coating carbon nanotube forests with superconducting niobium carbide (NbC) does not destroy the microstructure of the nanotubes. NbC also shows much improved superconducting properties such as a higher irreversibility and upper critical field.

A chemical solution approach for superconducting and hard epitaxial NbC film.

Epitaxial NbC thin films were grown by a chemical solution technique, polymer assisted deposition. High quality epitaxial NbC film showed a transition temperature of 10 K and a hardness of 19.54 GPa.

Chemical solution deposition of epitaxial carbide films.

Carbide films exhibit many unique properties. The development of a versatile and simple technique for the deposition of carbide films will enable a wide range of technological applications. Here we report a cost-effective chemical solution deposition or polymer-assisted deposition method for growing epitaxial carbide (including TiC, VC, and TaC) films.

Beryllium alters lipopolysaccharide-mediated intracellular phosphorylation and cytokine release in human peripheral blood mononuclear cells.

Beryllium exposure in susceptible individuals leads to the development of chronic beryllium disease, a lung disorder marked by release of inflammatory cytokine and granuloma formation. We have previously reported that beryllium induces an immune response even in blood mononuclear cells from healthy individuals. In this study, we investigate the effects of beryllium on lipopolysaccharide-mediated cytokine release in blood mononuclear and dendritic cells from healthy individuals.

Beryllium and strong hydrogen bonds.

We compare beryllium to H+ and show that beryllium can displace H+ in many "strong hydrogen bonds" where Be as a "tetrahedral proton" (O-Be-O angle is tetrahedral as opposed to the nearly linear O-H-O angle) is thermodynamically preferred. The strong hydrogen bond provides two advantages. First, the O-X distance in a strong hydrogen bond is in the range 2.

Recent advances in understanding the biomolecular basis of chronic beryllium disease: a review.

In this review we summarize the work conducted over the past decade that has advanced our knowledge of pulmonary diseases associated with exposure to beryllium that has provided a molecular-based understanding of the chemistry, immunopathology, and immunogenetics of beryllium toxicity. Beryllium is a strong and lightweight metal that generates and reflects neutrons, resists corrosion, is transparent to X-rays, and conducts electricity. Beryllium is one of the most toxic elements on the periodic table, eliciting in susceptible humans (a) an allergic immune response known as beryllium sensitization (BeS); (b) acute beryllium disease, an acutely toxic, pneumonitis-like lung condition resulting from exposure to high beryllium concentrations that are rarely seen in modern industry; and (c) chronic beryllium disease (CBD) following either high or very low levels of exposure.

Highly conductive films of layered ternary transition-metal nitrides.

Film studies: Epitaxial films of BaZrN(2) (see TEM image) and BaHfN(2) are grown by polymer-assisted deposition on SrTiO(3) (STO) substrates. The films are phase-pure, allowing the intrinsic physical properties of the ternary nitrides to be studied. From 5 to 300 K, the films exhibit metallic-like resistivity-temperature behavior, with large residual resistivity ratios.

Ultrathin epitaxial superconducting niobium nitride films grown by a chemical solution technique.

Ultrathin epitaxial superconducting NbN (18 nm) films, exhibiting a superconducting transition temperature of 14 K and a critical current density as high as 5.2 MA cm(-2) at 5 K under zero magnetic field, were grown on SrTiO(3) (STO) by a chemical solution technique, polymer assisted deposition (PAD).

Epitaxial ternary nitride thin films prepared by a chemical solution method.

It is indispensable to use thin films for many technological applications. This is the first report of epitaxial growth of ternary nitride AMN2 films. Epitaxial tetragonal SrTiN2 films have been successfully prepared by a chemical solution approach, polymer-assisted deposition.

The bioinorganic chemistry and associated immunology of chronic beryllium disease.

Chronic beryllium disease (CBD) is a debilitating, incurable, and often fatal disease that is caused by the inhalation of beryllium particulates. The growing use of beryllium in the modern world, in products ranging from computers to dental prosthetics (390 tons of beryllium in the US in the year 2000) necessitates a molecular based understanding of the disease in order to prevent and cure CBD. We have investigated the molecular basis of CBD at Los Alamos National Laboratory during the past six years, employing a multidisciplinary approach of bioinorganic chemistry and immunology.

Upregulation of I-CAM1 in response to beryllium exposure in small airway epithelial cells.

Chronic Beryllium Disease (CBD) is a delayed-type hypersensitivity immune reaction that leads to granuloma formation in the lungs and potentially severe loss of pulmonary function. Although the molecular mechanisms that mediate beryllium (Be)-stimulated granuloma formation are not well understood, cell adhesion molecules are likely to play a key role in the migration of immune cells to sites of inflammation. In this study, we examined the role of the cell adhesion molecule I-CAM1 in Be-stimulated small airway epithelial cells (SAECs).

Extraction and optical fluorescence method for the measurement of trace beryllium in soils.

Beryllium metal and beryllium oxide are important industrial materials used in a variety of applications in the electronics, nuclear energy, and aerospace industries. These materials are highly toxic, they must be disposed of with care, and exposed workers need to be protected. Recently, a new analytical method was developed that uses dilute ammonium bifluoride for extraction of beryllium and a high quantum yield optical fluorescence reagent to determine trace amounts of beryllium in airborne and surface samples.

Perturbation of local solvent structure by a small dication: a theoretical study on structural, vibrational, and reactive properties of beryllium ion in water.

A molecular based understanding of beryllium chemistry in the context of biomolecules is necessary for gaining progress in prevention and treatment of chronic beryllium disease. One aspect that has hindered the theoretical progress has been the lack of a simple classical two-body potential for the aqueous beryllium ion (Be2+) to be used with biomolecular simulations. We provide new parameters for Be2+ that capture the structural and reactive properties of this small dication.

Structure and magnetic behavior of transition metal based ionic liquids.

A series of ionic liquids containing different paramagnetic anions have been prepared and all show paramagnetic behavior with potential applications for magnetic and electrochromic switching as well as novel magnetic transport; also, the tetraalkylphosphonium-based ionic liquids reveal anomalous magnetic behavior.

Structural and ferromagnetic properties of epitaxial SrRuO3 thin films obtained by polymer-assisted deposition.

Epitaxial ferromagnetic SrRuO3 thin films with a room-temperature resistivity of 300 microOmega.cm have been successfully grown on LaAlO3(001) substrates at a processing temperature in the range of 550-750 degrees C by a polymer-assisted deposition technique. X-ray diffraction analysis shows good epitaxial quality of SrRuO3 thin films, giving values of the full width at half-maximum (FWHM) of 0.