Laboratory-based surveillance of Campylobacter and Salmonella infection and the importance of denominator data

Laboratory data are the cornerstone in surveillance of infectious disease. We investigated whether changes in reported incidence of Campylobacter and Salmonella infection might be explained by changes in stool sampling rates. Data were extracted from a national database on 585 843 patient stool samples tested by microbiology laboratories in Wales between 1998 and 2008. Salmonella incidence fell from 43 to 19 episodes/100 000 population but Campylobacter incidence after declining from 111/100 000 in 1998 to 84/100 000 in 2003 rose to 119/100 000 in 2008. The proportion of the population sampled rose from 2·0% in 1998 to 2·8% in 2008, mostly due to increases in samples from hospital patients and older adults. The proportion of positive samples declined for both Salmonella and Campylobacter from 3·1% to 1·1% and from 8·9% to 7·5%, respectively. The decline in Salmonella incidence is so substantial that it is not masked even by increased stool sampling, but the recent rise in Campylobacter incidence may be a surveillance artefact largely due to the increase in stool sampling in older people

Brain phospholipid precursors administered post-injury reduce tissue damage and improve neurological outcome in experimental traumatic brain injury

Traumatic brain injury (TBI) leads to cellular loss, destabilisation of membranes, disruption of synapses and altered brain connectivity, and increased risk of neurodegenerative disease. A significant and long-lasting decrease in phospholipids (PL), essential membrane constituents, has recently been reported in plasma and brain tissue, in human and experimental TBI. We hypothesised that supporting PL synthesis post-injury could improve outcome after TBI. We tested this hypothesis using a multi-nutrient combination designed to support the biosynthesis of phospholipids and available for clinical use. The multi-nutrient Fortasyn® Connect (FC) contains polyunsaturated omega-3 fatty acids, choline, uridine, vitamins, co-factors required for PL biosynthesis, and has been shown to have significant beneficial effects in early Alzheimer's disease. Male C57BL/6 mice received a controlled cortical impact injury and then were fed a control diet or a diet enriched with FC for 70 days. FC led to a significantly improved sensorimotor outcome and cognition, reduced lesion size and oligodendrocyte loss, and it restored myelin. It reversed the loss of the synaptic protein synaptophysin and decreased levels of the axon growth inhibitor Nogo-A, thus creating a permissive environment. It decreased microglia activation and the rise in ß-amyloid precursor protein and restored the depressed neurogenesis. The effects of this medical multi-nutrient suggest that support of PL biosynthesis after TBI, a new treatment paradigm, has significant therapeutic potential in this neurological condition for which there is no satisfactory treatment. The multi-nutrient tested has been used in dementia patients, is safe and well-tolerated, which would enable rapid clinical exploration in TBI

A view of surface science since 1960: Oxygen states at metal surfaces

The article describes how the application of experimental methods developed over the last 40 years (work function, photoemission, photoelectron spectroscopy and scanning tunnelling microscopy) enables our understanding of oxygen chemisorption to progress in a step-wise manner, with STM providing the ultimate atom-resolved evidence for the dynamics involved. Different oxygen states exhibit distinct reactivities and provide a stimulus for the design of catalysts with specific activities in oxidation catalysis. There is also evidence accruing that disordered oxygen states are in general more active in dehydrogenation reactions than the ordered states, with for example ammonia being `oxidised' to nitrogen adatoms at Cu(1 1 0) at cryogenic temperatures

Atom resolved surface reactions: nanocatalysis

This book offers a unique perspective of the impact of scanning probe microscopes on our understanding of the chemistry of the surface at the nanoscale. Research oriented, with the concepts gleaned from Scanning Tunnelling Microscopy being related to the more established and accepted views in surface chemistry and catalysis, the authors have addressed the question "How do the models based on classical spectroscopic and kinetic studies stand up to scrutiny at the atom-resolved level?". In taking this approach the reader, new to the field of surface chemistry, should be able to obtain a perspective on how the evidence from STM confirms or questions long standing tenets. An emphasis is given to "how did we get to where we are now" and a large number of figures from the literature are included along with suggestions for further reading. Topics discussed include: - the dynamics of oxygen chemisorption at metal surfaces - control of oxygen states and surface reconstruction - dissociative chemisorption of diatomic and hydrocarbon molecules - nanoparticles and chemical reactivity - STM at high pressures - structural studies of sulfur containing molecules and molecular templating This book will appeal to all those who wish to become familiar with the contribution Scanning Tunnelling Microscopy has made to the understanding of the field of surface chemistry and heterogeneous catalysis and also to those who are new to catalysis, a fascinating and important area of chemistry

Oxygen transient states in catalytic oxidation at metal surfaces

Mechanistic aspects of catalytic oxidation at metal surfaces have involved four distinct stages of investigation which, in chronological order, are: (a) oxygen chemisorption and surface reconstruction with evidence for discrete metal and oxygen states; (b) the reactivity of specific oxygen states in oxydehydrogenation reactions; (c) the chemistry under dynamic conditions with evidence for dioxygen–reactant complexes at low temperature; (d) atom resolved evidence from scanning tunnelling microscopy. We discuss how these studies draw attention to the advantages of dynamic studies in revealing individual steps in oxidation catalysis, the role of labile surface complexes in providing low energy pathways to products and their relevance to the theoretical calculations and experimental studies of Jerzy Haber and his colleagues

Activation of oxygen at metal surfaces

Oxygen chemisorption at metal surfaces has been shown through a combination of scanning tunnelling microscopy and photoelectron spectroscopy to involve transient states that provide low energy pathways for a wide range of surface reactions including the catalytic oxidation of ammonia and hydrocarbons. The kinetically ‘hot’ transients are disordered and mobile, become unreactive when they form ordered structures, and are characterized by non-classical kinetic behaviour. The role of surface additives (caesium) in controlling oxygen structures and the implications of oxygen transients for theory and reaction mechanisms in applied catalysis are considered

A reactive oxygen state at a barium promoted Au (100) surface: the oxidation of ethene at cryogenic temperatures

Although Au (100) does not adsorb oxygen at either 295 K or 80 K, a barium modified Au(100) surface is active in oxygen dissociation resulting, through surface diffusion of oxygen adatoms, in the formation of a chemisorbed oxygen adlayer. This oxygen species is inactive for ethene oxidation, as is the oxygen species pre-adsorbed at an Au(100)-Ba surface at 80 K, and the clean Au(100)-Ba surface. However, when molecularly adsorbed ethene present at a Au(100)-Ba surface at 80 K is exposed to dioxygen and warmed to 140 K, surface carbonate is observed. We conclude that a transient oxygen species is the oxidant

Transient Oxygen States in Catalysis: Ammonia Oxidation at Ag(111)

Although the reactive sticking probability of oxygen at Ag(111) is of the order of 10-6 at 295 K, ammonia oxidation is a facile process at low temperatures. A combination of quantitative analysis of photoelectron spectra together with high resolution electron energy loss spectroscopy provides kinetic and spectroscopic evidence for an ammonia-dioxygen complex, stable at 100 K, as the key intermediate. The reactive oxygen O2(s) is a transient dioxygen precursor of the unreactive peroxo state O2-(a). It is present as a complex when ammonia and dioxygen are coadsorbed at low temperature (100 K) with evidence from both O(1s) and energy loss spectra. Hydroxyl and amide/imide species are formed, followed by dehydroxylation and oxide formation at 260 K. This is a further example (zinc was the first) of how an sp-metal, where dioxygen bond cleavage is slow, provides an alternative pathway via a transient dioxygen state to catalytic oxidation through precursor assisted dioxygen bond cleavage. Whether it is a general characteristic of sp-metals remains to be established. Comparisons are made with the homogeneously catalyzed Gif reaction, the selective oxidation of hydrocarbons by dioxygen

Chemisorption and reaction of phenyl iodide at Cu(110) surfaces: a combined STM and XPS study

The chemisorption of phenyl iodide at a Cu(1 1 0) surface at 295 K has been studied with STM and XPS. Dissociative adsorption leads to chemisorbed iodine, which the STM shows to have a c(2 × 2) structure, and adsorbed phenyl groups which appear in the STM images as roughly circular features, approximately 0.7 nm in diameter and 0.1 nm above the iodine adlayer. The phenyl groups are stabilised at the top and bottom of step edges forming chains with a regular inter-phenyl spacing of 1.0 nm. Chains are also observed on the terraces but here they are usually “paired” in the 〈1 0 0〉 direction. From a comparison of the phenyl and iodine structures the adsorption site of the phenyl rings is shown to be either the two fold hollows or the atop sites with each ring blocking approximately four iodine adsorption sites