An unexpected oxidation : NaK5Cl2(S2O6)2 revisited

Acknowledgements We thank the EPSRC National Crystallography Service (University of Southampton) for the X-ray data collection.Peer reviewedPublisher PD

Porous and Close Packed Supramolecular Assemblies from 2,4-Difluoronitrobenzene with Three Different Linkers and an n-Butylamine Cap

Acknowledgments: We thank the UK EPSRC National Mass Spectrometry Service Centre for the mass spectrometric data and the UK National Crystallography Centre (University of Southampton) for the X-ray data collections. MJ Plater performed all syntheses and obtained the characterisation data, and WTA Harrison solved the crystallographic data sets. Data sets were obtained free of charge from the National Crystallography Centre, Southampton University.Peer reviewedPublisher PD

Crystal structures of two one-dimensional coordination polymers constructed from Mn2+ ions, chelating hexafluoro-acetylacetonate anions, and flexible bipyridyl bridging ligands

Original Russian Text © 2016 M. J. Plater, B. M. De Silva, M. R. St. J. Foreman, W. T. A. Harrison. The text was submitted by the authors in English. Zhurnal Strukturnoi Khimii, Vol. 57, No. 6, pp. 1230-1235, July-August, 2016.Peer reviewedPostprin

Modifying the stereochemistry of an enzyme-catalyzed reaction by directed evolution

Aldolases have potential as tools for the synthesis of stereochemically complex carbohydrates. Here, we show that directed evolution can be used to alter the stereochemical course of the reaction catalyzed by tagatose-1,6-bisphosphate aldolase. After three rounds of DNA shuffling and screening, the evolved aldolase showed an 80-fold improvement in k-cat/K-m toward the non-natural substrate fructose 1,6-bisphosphate, resulting in a 100-fold change in stereospecificity. (31)P NMR spectroscopy was used to show that, in the synthetic direction, the evolved aldolase catalyzes the formation of carbon—carbon bonds with unnatural diastereoselectivity, where the >99:<1 preference for the formation of tagatose 1,6-bisphosphate was switched to a 4:1 preference for the diastereoisomer, fructose 1,6-bisphosphate. This demonstration is of considerable significance to synthetic chemists requiring efficient syntheses of complex stereoisomeric products, such as carbohydrate mimetics

Sediment supply and barrier dynamics as driving mechanisms of Holocene coastal change for the southern North Sea basin

The combined effects of climate change and human impact lead to regional and local coastal responses that pose major challenges for the future resilience of coastal landscapes, increasing the vulnerability of communities, infrastructure and nature conservation interests. Using the Suffolk coast, southeast England, as a case study, we investigate the importance of sediment supply and barrier dynamics as driving mechanisms of coastal change throughout the Holocene. Litho-, bio- and chronostratigraphic methods are used to decipher the mechanisms of coastal change from the record preserved within coastal stratigraphy. Results suggest that local coastal configuration and sediment supply were the most influential in determining coastal change during the mid- and late Holocene, against a background control of sea-level rise. The importance of sedimentological and morphological factors in shaping Holocene coastal changes in the southern North Sea basin must therefore be considered when using the database of evidence from this region as an analogue for future change under accelerated sea-level rise

The effectiveness of beach mega-nourishment, assessed over three management epochs

Resilient coastal protection requires adaptive management strategies that build with nature to maintain long-term sustainability. With increasing pressures on shorelines from urbanisation, industrial growth, sea-level rise and changing storm climates soft approaches to coastal management are implemented to support natural habitats and maintain healthy coastal ecosystems. The impact of a beach mega-nourishment along a frontage of interactive natural and engineered systems that incorporate soft and hard defences is explored. A coastal evolution model is applied to simulate the impact of different hypothetical mega-nourishment interventions to assess their impacts’ over 3 shoreline management planning epochs: present-day (0–20 years), medium-term (20–50 years) and long-term (50–100 years). The impacts of the smaller interventions when appropriately positioned are found to be as effective as larger schemes, thus making them more cost-effective for present-day management. Over time the benefit from larger interventions becomes more noticeable, with multi-location schemes requiring a smaller initial nourishment to achieve at least the same benefit as that of a single-location scheme. While the longer-term impact of larger schemes reduces erosion across a frontage the short-term impact down drift of the scheme can lead to an increase in erosion as the natural sediment drift becomes interrupted. This research presents a transferable modelling tool to assess the impact of nourishment schemes for a variety of sedimentary shorelines and highlights both the positive and negative impact of beach mega-nourishment

A European interlaboratory trial to evaluate the performance of different PCR methods for Mycoplasma bovis diagnosis

Background Several species-specific PCR assays, based on a variety of target genes are currently used in the diagnosis of Mycoplasma bovis infections in cattle herds with respiratory diseases and/or mastitis. With this diversity of methods, and the development of new methods and formats, regular performance comparisons are required to ascertain diagnostic quality. The present study compares PCR methods that are currently used in six national veterinary institutes across Europe. Three different sample panels were compiled and analysed to assess the analytical specificity, analytical sensitivity and comparability of the different PCR methods. The results were also compared, when appropriate, to those obtained through isolation by culture. The sensitivity and comparability panels were composed of samples from bronchoalveolar fluids of veal calves, artificially contaminated or naturally infected, and hence the comparison of the different methods included the whole workflow from DNA extraction to PCR analysis. Results The participating laboratories used i) five different DNA extraction methods, ii) seven different real-time and/or end-point PCRs targeting four different genes and iii) six different real-time PCR platforms. Only one commercial kit was assessed; all other PCR assays were in-house tests adapted from published methods. The analytical specificity of the different PCR methods was comparable except for one laboratory where Mycoplasma agalactiae was tested positive. Frequently, weak-positive results with Ct values between 37 and 40 were obtained for non-target Mycoplasma strains. The limit of detection (LOD) varied from 10 to 103 CFU/ml to 103 and 106 CFU/ml for the real-time and end-point assays, respectively. Cultures were also shown to detect concentrations down to 102 CFU/ml. Although Ct values showed considerable variation with naturally infected samples, both between laboratories and tests, the final result interpretation of the samples (positive versus negative) was essentially the same between the different laboratories. Conclusion With a few exceptions, all methods used routinely in the participating laboratories showed comparable performance, which assures the quality of diagnosis, despite the multiplicity of the methods