Electronic structures of mixed-sandwich complexes of cyclopentadienyl and Hydrotris(pyrazolyl)borate ligands with 3d transition metals.

The electronic and magnetic properties of a series of mixed-sandwich complexes MCp(R)Tp (Cp(R) = Cp or Cp; Tp = hydrotris(pyrazolyl)borate; M = V, Cr, Fe, Co or Ni) have been studied and compared to their homoleptic analogues, MCp(R)(2) and MTp(2). Solid-state magnetic susceptibility measurements and EPR spectroscopic data indicate that complexes with d(3), d(6), and d(8) configurations are similar electronically to their metallocene analogues, except for FeCpTp, which displays a spin equilibrium (S = 0 if S = 2) in solution which was investigated by variable- temperature NMR spectroscopy. The d(2) complex [VCpTp](+) displays magnetic behavior consistent with an orbitally nondegenerate ground state.

Solid-state chelation of metal ions by ethylenediaminetetraacetate intercalated in a layered double hydroxide.

The solid-state chelation of transition metal ions (Co(2+), Ni(2+), and Cu(2+)) from aqueous solutions into the lithium aluminum layered double hydroxide ([LiAl(2)(OH)(6)]Cl x 0.5H(2)O or LDH) which has been pre-intercalated with EDTA (ethylenediaminetetraacetate) ligand has been investigated. The intercalated metal cations form [M(edta)](2)(-) complexes between the LDH layers as indicated by elemental analysis, powder X-ray diffraction, and IR and UV-vis spectroscopies.

Recent results from the in situ study of hydrothermal crystallisations using time-resolved X-ray and neutron diffraction methods.

We present new time-resolved powder diffraction data measured in situ during the hydrothermal crystallisation of two families of crystalline inorganic materials. In the first study, we have used time-resolved energy-dispersive X-ray diffraction (EDXRD) to follow the formation of zeolitic zinc phosphates from amine phosphates and zinc oxide in acidic solutions at 60-150 degrees C. The advantage of this method is the ability to penetrate a laboratory-sized reaction vessel and to measure data in short (< 1 min) time intervals.

[NC4H12]2[(UO2)6(H2O)2(SO4)7]: the first organically templated actinide sulfate with a three-dimensional framework structure.

[NC4H12][(UO2)6(H2O)2(SO4)7] is the first organically templated actinide sulfate with a three-dimensional framework structure; it has channels of dimensions 8.5 A x 8.5 A, running along the [001] direction, containing tetramethylammonium cations.

Mortality and morbidity in white water rafting in New Zealand.

Objectives: This study provides the first descriptive overview of fatal and non-fatal injury associated with white water and other recreational river rafting in New Zealand. The current study sought to identify the nature and causes of hospitalisable injuries and to identify the causes of fatal injuries to white water rafters.

Design: The data were obtained from the New Zealand Health Information Service (NZHIS) mortality and morbidity files.

The role of situation assessment and flight experience in pilots' decisions to continue visual flight rules flight into adverse weather.

Visual flight rules (VFR) flight into instrument meteorological conditions (IMC) is a major safety hazard in general aviation. In this study we examined pilots' decisions to continue or divert from a VFR flight into IMC during a dynamic simulation of a cross-country flight. Pilots encountered IMC either early or later into the flight, and the amount of time and distance pilots flew into the adverse weather prior to diverting was recorded.

The first organically templated thorium compounds, [C4N2H12]0.5[ThF5] and [C5N2H14][ThF6].0.5H2O.

Organically templated thorium compounds were synthesized for the first time under hydrothermal conditions; the piperazine containing compound consists of 2-D layers, while the 2-methylpiperazine phase contains unprecedented 1-D chains of face-sharing ThF9 polyhedra.

Pentalene complexes of group 7 metal carbonyls: an organometallic mixed-valence system with very large metal-metal electronic coupling.

The bimetallic complexes [M(CO)(3)](2)(mu:eta(5):eta(5)-Pn) (Pn = pentalene, C(8)H(6); M = Mn, Re) have been synthesized and characterized crystallographically; the Mn compound was isolated as solely the anti-isomer, while the Re analogue was formed as a mixture of anti- and syn-isomers. [Mn(CO)(3)](2)(mu:eta(5):eta(5)-Pn) may be reduced chemically to its mono- and dianions; the mixed-valence Mn(I)/Mn(0) monoanion is shown by ESR, vibrational, and electronic spectroscopies to be a Robin-Day class III system with an exceptionally large electronic coupling between the metal centers.

Direct in situ observation of increasing structural dimensionality during the hydrothermal formation of open-framework zinc phosphates.

The first time-resolved in situ X-ray diffraction studies of the hydrothermal crystallisation of open-framework zinc phosphates reveal a pathway of sequential crystallisation involving formation of a metastable low dimensional chain phase before the growth of three-dimensional zeolitic architectures.

Synthesis and characterisation of (C4N2H12)(UO2)2(PO3H)2(PO2(OH)H)2: a three dimensionally connected actinide framework.

The material (C4N2H12)(UO2)2(PO3H)2(PO2(OH)H)2 (MUPH-1) has been prepared hydrothermally; it is a three dimensional structure consisting of four intersecting elliptical shaped one-dimensional channels, the largest channel has dimensions of 13.1 x 7.2 A.

(eta 5-Cyclopentadienyl)(kappa 3-hydrotris(pyrazolyl)borate)cobalt(II)--the first high-spin cobalt organometallic complex.

(eta 5-Cyclopentadienyl)(kappa 3-hydrotris(pyrazolyl)borate)-cobalt(II) has been synthesised; magnetic and crystallographic data indicate this to be the first example of a high-spin cobalt organometallic complex whilst its pentamethylcyclopentadienyl analogue is found to have a low-spin electronic configuration.

Intercalation and controlled release of pharmaceutically active compounds from a layered double hydroxide.

A series of pharmaceutically active compounds including diclofenac, gemfibrozil, ibuprofen, naproxen, 2-propylpentanoic acid, 4-biphenylacetic acid and tolfenamic acid can be reversibly intercalated into a layered double hydroxide, initial studies suggest that these materials may have application as the basis of a novel tuneable drug delivery system.

Direct and indirect cost of general aviation crashes.

Background: There have been few well-designed studies which estimate the costs inflicted on society from injuries, fatalities, and property damage caused by aviation crashes. Furthermore, indirect cost estimates from the human capital (HC) approach tend to be substantially smaller than those obtained from the willingness-to-pay (WTP) approach.

Objectives: To estimate the direct and indirect costs of general aviation crashes in New Zealand, and to contrast the HC and WTP approaches used to estimate indirect costs.

Delamination of layered double hydroxides in polar monomers: new LDH-acrylate nanocomposites.

The layered double hydroxide Mg2Al(OH)6(C12H25SO4) was delaminated to give high levels of inclusion in acrylate monomers; subsequent polymerisation of the monomers containing the LDH dispersion gave polyacrylates with the inorganic component still in the delaminated form.

Two chain gallium fluorodiphosphates: synthesis, structure solution, and their transient presence during the hydrothermal crystallisation of a microporous gallium fluorophosphate.

Two novel gallium fluorodiphosphates have been isolated and their structures solved ab initio from powder X-ray diffraction data; the materials readily interconvert under hydrothermal conditions, and are metastable with respect to an open-framework zeolitic gallium fluorophosphate, during the synthesis of which they are present as transient intermediates.

Cross-country VFR crashes: pilot and contextual factors.

Background: General Aviation (GA) cross-country crashes, particularly those involving weather, continue to be a major source of fatalities, with a fatality rate more than four times greater than for GA crashes in general. There has been much speculation and little solid evidence on the causes of these crashes.

Methods: We have designed a program of laboratory and database research into the causes of cross-country weather-related crashes including an analysis of air crashes in New Zealand between 1988 and 2000.

CrCpTp: a high-spin Cr(II) sandwich complex with a large structural distortion.

CrCpTp was synthesized from the reaction of [CrCpCl](2) and KTp. Magnetic measurements indicate it to have a high-spin (S = 2) electronic configuration from 5 to 300 K. A single-crystal X-ray study reveals bond lengths typical for a high-spin configuration and a pronounced Jahn-Teller distortion.

Real time observation of the hydrothermal crystallization of barium titanate using in situ neutron powder diffraction.

The hydrothermal crystallization of barium titanate, BaTiO3, has been studied in situ by time-resolved powder neutron diffraction methods using the recently developed Oxford/ISIS hydrothermal cell. This technique has allowed the formation of the ferroelectric ceramic to be followed in a noninvasive manner in real time and under genuine reaction conditions. In a first set of experiments, Ba(OD)2-8D2O was reacted with two different titanium sources, either crystalline TiO2 (anatase) or amorphous TiO2-H2O in D2O, at 100-140 degrees C and the reaction studied using the POLARIS time-of-flight neutron powder diffractometer, at the ISIS Facility.

Arterial blood sampling practices in intensive care units in England and Wales.

A postal survey of arterial blood sampling practices in 280 intensive care units throughout England and Wales found that very few measures are taken to reduce diagnostic blood loss in adult intensive care patients from arterial sampling. The average volume of blood withdrawn to clear the arterial line before sampling is 3.2 ml; subsequently returned to the patient in only 18.

Variable coordination modes of hydrotris(3-isopropyl-4-bromopyrazolyl)borate (Tp') in Fe(II), Mn(II), Cr(II), and Cr(III) Complexes: formation of MTp'Cl (M = Fe and Mn), structural isomerism in CrTp'(2), and the observation of Tp' (-) as an uncoordinated anion.

The syntheses of the 4-coordinate Tp'MCl complexes (where M = Fe (1), Mn (2); and Tp' = hydrotris(3-isopropyl-4-bromopyrazolyl)borate) are described. The single-crystal X-ray structures show that the metal centers have distorted tetrahedral coordination. Analogous reaction of CrCl(2)(MeCN)(2) with TlTp' gave Cr(kappa(3)-Tp')(kappa(2)-Tp') (3) as the initial product.

The use of botulinum toxin in otorhinolaryngology.

In recent years, the use of botulinum toxin has become more popular for the treatment of a wide variety of diseases in the head and neck. It offers the possibility of non-invasive treatment of conditions whose aetiology lies in neuromuscular dyskinesis.

Hydrothermal synthesis of (C6N2H14)2(UVI2UIVO4F12), a mixed-valent one-dimensional uranium oxyfluoride.

A new hybrid organic-inorganic mixed-valent uranium oxyfluoride, (C6N2H14)2(U3O4F12), UFO-17, has been synthesized under hydrothermal conditions using uranium dioxide as the uranium source, hydrofluoric acid as mineralizer, and 1,4-diazabicyclo[2.2.2]octane as template.

The 'Wheel of Misfortune': a taxonomic approach to human factors in accident investigation and analysis in aviation and other complex systems.

The analysis and reporting of the human factors aspects of accidents in aviation and other complex systems continues to present difficulties for investigators and analysts alike. Reason's 'latent conditions' model has had a major impact on the way accidents are conceptualized but it has proven difficult to apply as a practical tool. Recent attempts to overcome these difficulties are discussed and an alternative conceptualization is proposed.

High resolution imaging of the distribution and permeability of methyl viologen dication in bovine articular cartilage using scanning electrochemical microscopy.

Scanning electrochemical microscopy (SECM) has been used in the induced transfer (SECMIT) mode to image the permeability of a probe cation, methyl viologen (MV(2+)), in samples of articular cartilage. An ultramicroelectrode (UME), scanned just above the surface of a sample, is used to amperometrically detect the probe solute. The resulting depletion of MV(2+) in solution induces the transfer of this cation from the sample into the solution for detection at the UME.