We sought to examine the factors associated with bacteraemia and their outcome in children with pneumonia and severe acute malnutrition (SAM). All SAM children of either sex, aged 0–59 months, admitted to the Dhaka Hospital of the International Centre for Diarrhoeal Disease Research, Bangladesh with radiologically confirmed pneumonia from April 2011 to July 2012 were enrolled (n = 405). Comparison was made between pneumonic SAM children with (cases = 18), and without (controls = 387) bacteraemia. The death rate was significantly higher in cases than controls (28% vs. 8%, P < 0·01). In logistic regression analysis, after adjusting for potential confounders, the SAM children with pneumonia and bacteraemia more often had a history of lack of bacillus Calmette-Guérin (BCG) vaccination (odds ratio 7·39, 95% confidence interval 1·67–32·73, P < 0·01). The results indicate the importance of continuation of BCG vaccination which may provide benefit beyond its primary purpose.

The results of an experimental study of shear-free decaying grid-generated turbulence on both sides of a sharp interface between two homogeneous layers of different densities are presented. The evolution of turbulence and mixing were examined by simultaneously mapping the velocity (u, w) and density fields (ρ) and the vertical mass flux $F(=\overline{\rho w}/\rho\prime w\prime)$ together with flow visualization in a low-noise water tunnel. Buoyancy was induced by salinity differences so the value of the Schmidt number Sc = 700. Density stratification altered the inertial-buoyancy force balance (most simply expressed by Nt, the product of the buoyancy frequency N and turbulent timescale t) so as to attenuate turbulent velocity fluctuations, vertical motions and interfacial convolutions, normalized density fluctuations, vertical flux mass, and mean interfacial thickness. Vertical velocity fluctuations w′ were found to increase with distance from the interface, whereas the u′-distribution can be non-monotonic. The maximum value of the mass flux, F, was found to be about 0.5 which was less than the typical value of 0.7 for thermally stratified wind tunnel experiments for which Sc = 0.7. The vertical mass flux can be a combination of down-gradient and counter-gradient transport with the ratio varying with Nt (e.g. at Nt ≈ 5, the flux is counter-gradient). The flux Richardson number Rf was found to increase monotonically to values of approximately 0.05.

In this experimental study the mixing of passive scalars that arises from shear-free decaying grid-generated turbulence is examined. The flow configuration consists of two homogeneous layers of equal density separated by a sharp interface between different mean concentrations of passive scalar. Both layers flow through a turbulence-generating grid. To determine the effect of diffusivity the scalar was heat in one experiment and salt in a second. The Schmidt number – the ratio of momentum to species diffusivity – was 7 and 700 for heat and salt respectively. Velocity, scalar and flux fields were mapped and flow visualization was undertaken to study the flows.

Integral lengthscales and (scalar) flux were determined to be independent of diffusivity, whereas the scalar Taylor microscales varied with Schmidt number, Sc, thus illustrating the disparate effects of diffusivity on large and small scales. The time series of signals showed a correspondence between locations of wθ extrema and uw extrema. Flux wθ arose from intermittent events; and the magnitude of the time-averaged flux $\overline{w\theta}$ was found to depend on the frequency, rather than on variations in the amplitude of wθ events.

Two photocatalytic systems consisting of spatially organized electron donor/photosensitizer/oxide semiconductor/catalyst assemblies are described. The first consists of an aluminosilicate zeolite (mordenite or zeolite L) containing Pt clusters, methylviologen, and titanium oxide within the linear channels, together with a size-excluded photosensitizer RuL32+ (L = 4, 4-dicarboxy-2, 2-bipyridine) adsorbed at the TiO2 surface. The kinetics of photochemical charge separation and hydrogen evolution in the presence of sacrificial electron donors are reported. In the second system, a layered oxide semiconductor, K4−xHxNb6O17·nH2O, replaces the zeolite/TiO2/MV2+ composite. Using adsorbed RuL3 and visible light excitation, this material decomposes acidic iodide solutions into H2 and I3− with a quantum efficiency of 0.3 %.