Proline-derived structural phases on Cu{311}

Structural phases formed by adsorption of L-proline onto a Cu{311} surface in ultra-high vacuum were investigated using reflection-absorption infrared spectroscopy, low-energy electron diffraction and scanning tunnelling microscopy. An ordered structural phase formed by self-assembly of L-prolinate with (2,1;1,2) periodicity, and a transition from pure l3 bonding to a mixture of l3 and l2 bonding with increasing exposure at 300 K, were observed. This behaviour has broad parallels with that previously seen with alaninate and glycinate on Cu{311}, but the detailed correlation between structure and bonding, and their evolution during subsequent annealing, are markedly different for prolinate as compared to alaninate and glycinate. At annealing temperatures around 480–490 K, a new structural phase with (5,3;4,6) periodicity emerges. We tentatively attribute this to pyrrole-2-carboxylate, formed by dehydrogenation and aromatization of the pyrrolidine ring of prolinate. The observation of equal areas of the two possible mirror domains associated with the two possible adsorbate–substrate bonding enantiomers implies a prochiral intermediate.The Engineering and Physical Sciences Research Council is acknowledged for financial support.This is the final published version. It first appeared at http://link.springer.com/article/10.1007/s11244-015-0400-2

Dynamic variation of supernatant quality in a dairy shed waste stabilisation pond system

An intensive monitoring program of a standard two-stage dairy shed waste stabilisation pond system was undertaken to determine the incidence and extent of spatial and temporal variation of basic physio-chemical parameters, and to shed light on the longer term dynamic nature of in-pond conditions. The anaerobicâfacultative pond system, located in a remote rural area, treats wastewater from the hosing down and hydraulic flushing of the milking parlour and holding yard at the farm dairy shed. A number of multi-parameter water quality field monitoring probes were permanently deployed at various locations within the two ponds to enable continuous measurement of temperature, pH, conductivity and dissolved oxygen. In addition, profiling of the supernatant of both ponds was undertaken at different times of the year to examine vertical variation of the same parameters. Continuous monitoring revealed spatial homogeneity in EC and pH levels in the upper metre of both ponds. Physio-chemical parameters also appear to change uniformly across the ponds in response to external stimuli such as rainfall. Neither pond, however, exhibits homogeneity down the profile of the supernatant. Seasonal stratification is prevalent in the facultative pond suggesting poor vertical mixing, while the anaerobic pond is notably affected by sludge accumulation. A long-term pattern of rising conductivity in both ponds indicated accumulation of dissolved salt species in the system due to recirculation of reclaimed effluent for hydraulic flushing of the dairy shed. In the facultative pond, diurnal fluctuations in dissolved oxygen, oxidation-reduction potential and turbidity during warmer months of the year closely followed temperature swings. The extensive data collected in this study provides a detailed picture of the physio-chemical dynamics of two-stage stabilisation pond systems treating dairy shed wastewater

Epitaxial growth of few-layer MoS2(0001) on FeS2{100}.

Physical vapour deposition of Mo on an FeS2{100} surface was performed at 170 K. Near-epitaxial growth of MoS2(0001) overlayers of the order of 1 nm thickness was observed when the Mo-covered substrate was subsequently heated to 600 K.The authors thank the EPSRC (grant ref. EP/E039782/1) for funding.This is the final published version. It first appeared at http://pubs.rsc.org/en/Content/ArticleLanding/2015/CC/c4cc06628f#!divAbstract

The crystalline structure of the phenazine overlayer physisorbed on a graphite surface

The monolayer crystal structure of phenazine adsorbed on graphite is determined by a combination of synchrotron X-ray diffraction and DFT calculations. The molecules adopt a rectangular unit cell with lattice parameters a = 13.55 Å and b = 10.55 Å, which contains 2 molecules. The plane group of the unit cell is p2gg, and each molecule is essentially flat to the plane of the surface, with only a small amount of out-of-plane tilt. Density Functional Theory (DFT) calculations find a minimum energy structure with a unit cell which agrees within 7.5% with that deduced by diffraction. DFT including dispersion force corrections (DFT+D) calculations help to identify the nature of the intermolecular bonding. The overlayer interactions are principally van der Waals, with a smaller contribution from weak C-H•••N hydrogen bonds. This behaviour is compared with that of 4,4’-bipyridyl.We acknowledge financial support for AB from an EPSRC DTA award from the Department of Chemistry, University of Cambridge; and BP for financial support for CT. We thank Diamond Light Source for access to beamline I11 (EE7761) that contributed to the results presented here. The DFT calculations were performed using the Darwin Supercomputer of the University of Cambridge High Performance Computing Service.This is the accepted manuscript. The final version is available from Taylor & Francis at http://www.tandfonline.com/doi/abs/10.1080/00268976.2013.793844#.VGHd34XziEo

Across the great divide: genetic forensics reveals misidentification of endangered cutthroat trout populations

Accurate assessment of species identity is fundamental for conservation biology. Using molecular markers from the mitochondrial and nuclear genomes, we discovered that many putatively native populations of greenback cutthroat trout (Oncorhynchus clarkii stomias) comprised another subspecies of cutthroat trout, Colorado River cutthroat trout (Oncorhynchus clarkii pleuriticus). The error can be explained by the introduction of Colorado River cutthroat trout throughout the native range of greenback cutthroat trout in the late 19th and early 20th centuries by fish stocking activities. Our results suggest greenback cutthroat trout within its native range is at a higher risk of extinction than ever before despite conservation activities spanning more than two decades

Low alanine aminotransferase and higher cardiovascular events in type 2 diabetes: analysis of the Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) study

Aims Non-alcoholic fatty liver disease (NAFLD) is common in type 2 diabetes and associated with higher risk of cardiovascular disease. This study aimed to determine whether alanine aminotransferase (ALT) or gamma-glutamyltransferase (GGT), as markers of liver health and NAFLD, might predict cardiovascular events in this population. Methods Data from the Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) study were analysed to examine the relationship between liver enzymes and incident cardiovascular events (nonfatal myocardial infarction, stroke, coronary and other cardiovascular death, coronary or carotid revascularization) over 5 years. Results ALT had a linear inverse relationship with the first cardiovascular event on study. After adjustment, for every standard deviation higher baseline ALT (13.2U/L), the risk of an event was 7%(95%CI 4–13, P=0.02) lower. Participants with ALT below and above the reference range 8–41 U/L for women and 9–59 U/L for men, had a hazard ratio of an event of 1.86(95%CI, 1.12–3.09) and 0.65(95%CI, 0.49–0.87), respectively (P=0.001). No relationship was found for GGT. Conclusions The data may indicate that in type 2 diabetes — associated with higher ALT due to prevalent NAFLD — lower ALT is a marker of hepatic or systemic frailty rather than health

Time-Delay Interferometry

Equal-arm interferometric detectors of gravitational radiation allow phase measurements many orders of magnitude below the intrinsic phase stability of the laser injecting light into their arms. This is because the noise in the laser light is common to both arms, experiencing exactly the same delay, and thus cancels when it is differenced at the photo detector. In this situation, much lower level secondary noises then set overall performance. If, however, the two arms have different lengths (as will necessarily be the case with space-borne interferometers), the laser noise experiences different delays in the two arms and will hence not directly cancel at the detector. In order to solve this problem, a technique involving heterodyne interferometry with unequal arm lengths and independent phase-difference readouts has been proposed. It relies on properly time-shifting and linearly combining independent Doppler measurements, and for this reason it has been called Time-Delay Interferometry (or TDI). This article provides an overview of the theory and mathematical foundations of TDI as it will be implemented by the forthcoming space-based interferometers such as the Laser Interferometer Space Antenna (LISA) mission. We have purposely left out from this first version of our ``Living Review'' article on TDI all the results of more practical and experimental nature, as well as all the aspects of TDI that the data analysts will need to account for when analyzing the LISA TDI data combinations. Our forthcoming ``second edition'' of this review paper will include these topics.Comment: 51 pages, 11 figures. To appear in: Living Reviews. Added conten