Both tuberculosis and bronchiectasis carry a significant burden worldwide in terms of morbidity and mortality, as well as financial, especially in the developing world. Epidemiological data for tuberculosis are now more readily available since the World Health Organisation declared it 'a global emergency' in 1993. The global prevalence of bronchiectasis, a recognized sequel of tuberculosis, is unknown, but is by no means insignificant. The pathophysiology of chronic airflow obstruction in both of these diseases is poorly understood, but it is associated with an accelerated rate of loss in pulmonary function. This article examines the global burden of tuberculosis and bronchiectasis, and focuses on the interrelation with chronic airflow obstruction.

Tuberculosis is increasing in incidence in many large cities in the UK. This contrasts with stable or declining rates in most western European countries. Ibrahim Abubakar and colleagues explain why and describe what needs to be done to regain control

Impetigo, a common skin infection, has shown seasonal variation in African, Australian and Indian studies. We investigated seasonal variation of impetigo in a UK paediatric population. A total of 1552 children with impetigo were seen in the Accident and Emergency (A&E) department between 1996 and 2003. The number of impetigo cases was always higher in late summer than in winter, and furthermore, increased year on year. These changes could not be accounted for by variation in total patient numbers seen in A&E, and suggest a correlation between impetigo frequency and climatic temperature. Possible reasons for these findings include exposed skin due to loose clothing in the summer leading to more skin-to-skin contact and minor trauma.

We demonstrate here a method using a multi-probe UHV instrument to isolate and measure individual metal contacts controllably fabricated on the tips of free standing ZnO nanowires (NWs). The measurements show Au can form reliable Ohmic and rectifying contacts by exercising control over the surface properties. In the as-grown state the Au contacts display low-resistance characteristics which are determined by the adsorbed species and defects on the NW surface. Subjecting the NWs to an oxidising agent (H2O2) increases the surface potential barrier creating more rectifying contacts. These developments are crucial for controllable NW array devices.

Objectives of this study were to determine the prevalence of positive tuberculin reactivity and associated factors among elderly nursing home residents in a population with a relatively high tuberculosis notification rate, to estimate the prevalence of active tuberculosis, and to assess tuberculin reactivity as a screening tool. A stratified, disproportional, randomized cluster sample of residents was selected and the Mantoux test (using 0.1 ml of 5 tuberculin units of purified protein derivative of tuberculin) carried out. All subjects with a positive test had a chest X-ray followed by sputum smear and culture if the X-ray was abnormal. Sputum examination was also carried out in a random sample of controls, matched for age and gender, drawn from subjects with a negative Mantoux test. Information regarding medical history, tobacco smoking habits, symptoms related to tuberculosis, and communal eating habits were gathered. Also anthropometric data were collected. Sixteen nursing homes in the catchment area of a major district hospital in Hong Kong comprising 587 residents (136 men, 451 women, mean age 80 ± 8 years) participated in this study. The weighted prevalence of tuberculin reactivity was 43.8%. It was higher in men, among those who took their meals in a common area, in the younger age group, and in those with no previous history of hospitalization. No association was found between prevalence and duration of residence, smoking, skinfold thickness, past medical history, or any relevant symptoms. Following radiological and sputum examination, the estimated prevalence of active tuberculosis ranged from 1.2 to 2.6%. The sensitivity of the tuberculin test was 86, the specificity 30%. The prevalence of active tuberculosis in nursing homes in Hong Kong is high, but it is unclear whether cross-infection or poor health of the residents is the major contributing factor. Tuberculin skin testing does not appear to be a useful screening method in this population.

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Correlative imaging provides a method of investigating complex systems by combining analytical (chemistry) and imaging (tomography) information across dimensions (2D-3D) and scales (centimetres-nanometres). We studied weathering processes in a modern cryptogamic ground cover from Iceland, containing early colonizing, and evolutionary ancient, communities of mosses, lichens, fungi, and bacteria. Targeted multi-scale X-ray Microscopy of a grain in-situ within a soil core revealed networks of surficial and internal features (tunnels) originating from organic-rich surface holes. Further targeted 2D grain characterisation by optical microscopy (OM), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (SEM–EDS), following an intermediate manual correlative preparation step, revealed Fe-rich nodules within the tunnels. Finally, nanotomographic imaging by focussed ion beam microscopy (FIB-SEM) revealed coccoid and filamentous-like structures within subsurface tunnels, as well as accumulations of Fe and S in grain surface crusts, which may represent a biological rock varnish/glaze. We attribute these features to biological processes. This work highlights the advantages and novelty of the correlative imaging approach, across scales, dimensions, and modes, to investigate biological weathering processes. Further, we demonstrate correlative microscopy as a means of identifying fingerprints of biological communities, which could be used in the geologic rock record and on extra-terrestrial bodies.

Correlative imaging combines information from multiple modalities (physical–chemical–mechanical properties) at various length scales (centimetre to nanometre) to understand the complex biological materials across dimensions (2D–3D). Here, we have used numerous coupled systems: X-ray microscopy (XRM), scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), optical light microscopy (LM) and focused ion beam (FIB-SEM) microscopy to ascertain the microstructural and crystallographic properties of the wall-plate joints in the barnacle Semibalanus balanoides . The exoskeleton is composed of six interlocking wall plates, and the interlocks between neighbouring plates (alae) allow barnacles to expand and grow while remaining sealed and structurally strong. Our results indicate that the ala contain functionally graded orientations and microstructures in their crystallography, which has implications for naturally functioning microstructures, potential natural strengthening and preferred oriented biomineralization. Elongated grains at the outer edge of the ala are oriented perpendicularly to the contact surface, and the c -axis rotates with the radius of the ala. Additionally, we identify for the first time three-dimensional nanoscale ala pore networks revealing that the pores are only visible at the tip of the ala and that pore thickening occurs on the inside (soft bodied) edge of the plates. The pore networks appear to have the same orientation as the oriented crystallography, and we deduce that the pore networks are probably organic channels and pockets, which are involved with the biomineralization process. Understanding these multiscale features contributes towards an understanding of the structural architecture in barnacles, but also their consideration for bioinspiration of human-made materials. The work demonstrates that correlative methods spanning different length scales, dimensions and modes enable the extension of the structure–property relationships in materials to form and function of organisms.