The community hospital: a three-year study

In a three-year period a community hospital of 40 beds discharged 2086 patients, their mean length of stay being 14.8 days. Some 68% of the patients treated were over 65, and 8.9% died in hospital. While the most common diagnosis on admission was disease of the respiratory tract, this does not indicate the actual cause of admission. For 142 patients from one practice this was acute illness in 44% of the cases, assessment in 20%, and a need for nursing care in 36%. If the community hospital had not been available about half these patients would have been admitted to the general hospital.     

Cooperative mechanisms of fast-ion conduction in gallium-based oxides with tetrahedral moieties

The need for greater energy efficiency has garnered increasing support for the use of fuel-cell technology, a prime example being the solid-oxide fuel cell. A crucial requirement for such devices is a good ionic (O(2-) or H+) conductor as the electrolyte. Traditionally, fluorite- and perovskite-type oxides have been targeted, although there is growing interest in alternative structure types for intermediate-temperature (400-700 ( composite function)C) solid-oxide fuel cells. In particular, structures containing tetrahedral moieties, such as La(1-x)Ca(x)MO(4-x/2)(M=Ta,Nb,P) (refs 7,8), La(1-x)Ba(1+x)GaO(4-x/2) (refs 9,10) and La(9.33+x)Si(6)O(26+3x/2) (ref. 11), have been attracting considerable attention recently. However, an atomic-scale understanding of the conduction mechanisms in these systems is still lacking; such mechanistic detail is important for developing strategies for optimizing the conductivity, as well as identifying next-generation materials. In this context, we report a combined experimental and computational modelling study of the La(1-x)Ba(1+x)GaO(4-x/2) system, which exhibits both proton and oxide-ion conduction. Here we show that oxide-ion conduction proceeds via a cooperative 'cog-wheel'-type process involving the breaking and re-forming of Ga(2)O(7) units, whereas the rate-limiting step for proton conduction is intra-tetrahedron proton transfer. Both mechanisms are unusual for ceramic oxide materials, and similar cooperative processes may be important in related systems containing tetrahedral moieties.     

Nanoparticle-mediated coupling of light into a nanowire

We show that a nanoparticle can serve as an efficient antenna for coupling of visible light into propagating plasmons of an Ag nanowire. For long wires, the coupling is maximal for incident light polarized perpendicular to the nanowire. For sub-10-mum nanowires, the polarization corresponding to maximum emission from the ends of the nanowire was found to be strongly dependent on the nanowire geometry and position of the vicinal nanoparticle. This nanoparticle antenna-based approach offers a potential strategy for optimizing plasmon coupling into nanoscale metallic waveguides.     

HVOF-Sprayed Nylon-11 + Nanodiamond Composite Coatings: Production & Characterization

High velocity oxy-fuel (HVOF) combustion spraying has previously been shown to be a viable method for depositing polymer and polymer/ceramic composite coatings. The addition of hard particulate reinforcing phases to soft polymeric matrices should improve their durability and sliding wear performance. Nanosized diamond is an ideal reinforcing phase, owing to its high hardness, low coefficient of friction, and desirable thermal properties. Composite coatings comprising a Nylon-11 matrix reinforced with nanodiamonds have been successfully produced by HVOF. An important challenge is preserving the structure of the nanoparticles after thermal spray deposition and achieving their uniform dispersion within the polymeric matrix. Raman spectroscopy and x-ray diffraction were used to confirm the presence and retention of nanodiamonds after HVOF deposition. Understanding of the role of process parameters, including the content of reinforcing phase in the matrix and powder preparation route is necessary. Nanoindentation studies demonstrated an improvement in creep behavior and recovery of the HVOF Nylon-11/nanodiamond composites subjected to deformation.     

Synthesis and structural characterization of stabilized aluminum borohydride adducts with triethylenediamine

The 1:1 and 1:2 adducts of aluminum borohydride (Al(BH₄)₃) and the Lewis base triethylenediamine (TEDA) and their thermal decomposition products were synthesized and structurally characterized by Raman spectroscopy, X-ray diffraction, and thermogravimetric analysis. Both adducts are more stable than Al(BH₄)₃ with respect to thermal decomposition and release of diborane. The structural analysis indicates that stabilization occurs through the donation of electron density through the N–Al dipolar bonds, leading to a more ionic character of the borohydride subunit. The 1:2 adduct, which has more electron donation, shows more ionic character and greater stability. For both adducts, the displaced borohydride group forms a dipolar bond with the second N lone pair of the TEDA, preserving much of the H content of the material. Decomposition occurs by internal rearrangement of borohydride, forming 1:1 and 1:2 TEDA·BH₃ adducts, followed by release of H₂ from the Al bonding center. The relative stability of the adducts encourages continuing exploration of Lewis base-stabilized borohydrides as an improved hydrogen storage material.