On the identification of twinning in body-centred cubic nanoparticles

Many metals and alloys, including Fe and W, adopt body-centred cubic (BCC) crystal structures and nanoparticles of these metals are gaining significant scientific and industrial relevance. Twinning has a marked effect on catalytic activity, yet there is little evidence for or against the presence of twinning in BCC nanoparticles. Here, we explore the potential shapes of twinned BCC nanoparticles, and predict their electron microscopy and diffraction signatures. BCC single crystal and twinned shapes often appear similar and diffraction patterns along common, low-index zone axes are often indistinguishable, casting doubt on many claims of single crystallinity. We conclude by outlining how nanoparticles can be characterized to conclusively prove the presence or absence of twinning

Groundwater in the Inner Bluegrass Karst Region, Kentucky

The hydrogeology of about 12% of the 5600 km2 Inner Bluegrass Karst Region of central Kentucky was investigated by water tracing and other techniques. Using fluorescent dyes adsorbed on fabric and charcoal detectors, 96 traces (average length 2.7 km, maximum length 15 km) resulted in the identification of 38 groundwater basins (with areas up to 15 km2). Within the basins, subsurface flow is in a dendritic conduit system at depths up to 30 m below the surface, while in the interbasin areas which separate them flow is generally less than 5 m deep. Each groundwater basin discharges at a spring whose median discharge is approximately 20 l/s·km2 of basin area. The largest spring (Royal Spring) in the study area has a median discharge greater than 300 l/s (Meinzer second magnitude). The Ordovician Lexington Limestone which underlies the region is thin bedded with shale partings and argillaceous units. Within groundwater basins, sinkhole drains and other conduits have breached the interbedded shales and descend nearly vertically to a level determined by equilibrium flow in the larger conduits. The general location and flow directions in groundwater basins is probably determined by a potentiometric gradient prior to conduit development, and some basins are localized by a favorably oriented regional joint set or other structural element. Otherwise, lithologic and structural factors have little influence in the occurrence and flow of subsurface water in the region

Decoration of plasmonic Mg nanoparticles by partial galvanic replacement.

Plasmonic structures have attracted much interest in science and engineering disciplines, exploring a myriad of potential applications owing to their strong light-matter interactions. Recently, the plasmonic concentration of energy in subwavelength volumes has been used to initiate chemical reactions, for instance by combining plasmonic materials with catalytic metals. In this work, we demonstrate that plasmonic nanoparticles of earth-abundant Mg can undergo galvanic replacement in a nonaqueous solvent to produce decorated structures. This method yields bimetallic architectures where partially oxidized 200-300 nm Mg nanoplates and nanorods support many smaller Au, Ag, Pd, or Fe nanoparticles, with potential for a stepwise process introducing multiple decoration compositions on a single Mg particle. We investigated this mechanism by electron-beam imaging and local composition mapping with energy-dispersive X-ray spectroscopy as well as, at the ensemble level, by inductively coupled plasma mass spectrometry. High-resolution scanning transmission electron microscopy further supported the bimetallic nature of the particles and provided details of the interface geometry, which includes a Mg oxide separation layer between Mg and the other metal. Depending on the composition of the metallic decorations, strong plasmonic optical signals characteristic of plasmon resonances were observed in the bulk with ultraviolet-visible spectrometry and at the single particle level with darkfield scattering. These novel bimetallic and multimetallic designs open up an exciting array of applications where one or multiple plasmonic structures could interact in the near-field of earth-abundant Mg and couple with catalytic nanoparticles for applications in sensing and plasmon-assisted catalysis.Support for this project was provided by the EU Framework Programme for Research and Innovation Horizon 2020 (Starting Grant SPECs 804523). J.A. wishes to acknowledge financial support from Natural Sciences and Engineering Research Council of Canada and “Fonds de Recherche Québec – Nature et Technologies” postdoctoral fellowships (BP and B3X programs). C.B. is thankful for funding from the Engineering and Physical Sciences Research Council (Standard Research Studentship (DTP) EP/R513180/1), and E.R.H. for support from the EPSRC NanoDTC Cambridge (EP/L015978/1). S.M.C. acknowledges support from the Henslow Research Fellowship at Girton College, Cambridge. We acknowledge access and support in the use of the electron Physical Sciences Imaging Centre (MG21980) at the Diamond Light Source, U.K

Second to fourth digit ratio (2D:4D) and concentrations of circulating sex hormones in adulthood

<p>Abstract</p> <p>Background</p> <p>The second to fourth digit ratio (2D:4D) is used as a marker of prenatal sex hormone exposure. The objective of this study was to examine whether circulating concentrations of sex hormones and SHBG measured in adulthood was associated with 2D:4D.</p> <p>Methods</p> <p>This analysis was based on a random sample from the Melbourne Collaborative Cohort Study. The sample consisted of of 1036 men and 620 post-menopausal women aged between 39 and 70 at the time of blood draw. Concentrations of circulating sex hormones were measured from plasma collected at baseline (1990-1994), while digit length was measured from hand photocopies taken during a recent follow-up (2003-2009). The outcome measures were circulating concentrations of testosterone, oestradiol, dehydroepiandrosterone sulphate, androstenedione, Sex Hormone Binding Globulin, androstenediol glucoronide for men only and oestrone sulphate for women only. Free testosterone and oestradiol were estimated using standard formulae derived empirically. Predicted geometric mean hormone concentrations (for tertiles of 2D:4D) and conditional correlation coefficients (for continuous 2D:4D) were obtained using mixed effects linear regression models.</p> <p>Results</p> <p>No strong associations were observed between 2D:4D measures and circulating concentrations of hormones for men or women. For males, right 2D:4D was weakly inversely associated with circulating testosterone (predicted geometric mean testosterone was 15.9 and 15.0 nmol/L for the lowest and highest tertiles of male right 2D:4D respectively (<it>P</it>-<it>trend </it>= 0.04). There was a similar weak association between male right 2D:4D and the ratio of testosterone to oestradiol. These associations were not evident in analyses of continuous 2D:4D.</p> <p>Conclusions</p> <p>There were no strong associations between any adult circulating concentration of sex hormone or SHGB and 2D:4D. These results contribute to the growing body of evidence indicating that 2D:4D is unrelated to adult sex hormone concentrations.</p

Detection of skewed X-chromosome inactivation in Fragile X syndrome and X chromosome aneuploidy using quantitative melt analysis.

Methylation of the fragile X mental retardation 1 (FMR1) exon 1/intron 1 boundary positioned fragile X related epigenetic element 2 (FREE2), reveals skewed X-chromosome inactivation (XCI) in fragile X syndrome full mutation (FM: CGG &gt; 200) females. XCI skewing has been also linked to abnormal X-linked gene expression with the broader clinical impact for sex chromosome aneuploidies (SCAs). In this study, 10 FREE2 CpG sites were targeted using methylation specific quantitative melt analysis (MS-QMA), including 3 sites that could not be analysed with previously used EpiTYPER system. The method was applied for detection of skewed XCI in FM females and in different types of SCA. We tested venous blood and saliva DNA collected from 107 controls (CGG &lt; 40), and 148 FM and 90 SCA individuals. MS-QMA identified: (i) most SCAs if combined with a Y chromosome test; (ii) locus-specific XCI skewing towards the hypomethylated state in FM females; and (iii) skewed XCI towards the hypermethylated state in SCA with 3 or more X chromosomes, and in 5% of the 47,XXY individuals. MS-QMA output also showed significant correlation with the EpiTYPER reference method in FM males and females (P &lt; 0.0001) and SCAs (P &lt; 0.05). In conclusion, we demonstrate use of MS-QMA to quantify skewed XCI in two applications with diagnostic utility

Correction to “Evidence for asymmetric nonvolcanic rifting and slow incipient oceanic accretion from seismic reflection data on the Newfoundland margin”

Author Posting. © American Geophysical Union, 2006. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 111 (2006): B12403, doi:10.1029/2006JB004769

Association of chronic musculoskeletal pain with mortality among UK adults: A population-based cohort study with mediation analysis.

BACKGROUND: We aimed to quantify the association between chronic musculoskeletal pain and all-cause mortality, and to investigate the extent to which this association is mediated by physical activity, smoking status, alcohol consumption, and opioid use. METHODS: For this population-based cohort study, we used data from UK Biobank, UK between baseline visit (2006-2010) to 18th December 2020. We assessed the associations between chronic musculoskeletal pain and all-cause mortality using a Cox proportional hazards model. We performed causal mediation analyses to examine the proportion of the association between chronic musculoskeletal pain and all-cause mortality. FINDINGS: Of the 384,367 included participants, a total of 187,269 participants reported chronic musculoskeletal pain. Higher number of pain sites was associated with increased risk of all-cause mortality compared to having no pain (e.g., four sites vs no site of pain, Hazard Ratio [HR] 1.46, 95% Confidence Interval [CI] 1.35 to 1.57). The multiple mediator analyses showed that the mediating proportions of all four mediators ranged from 53.4% to 122.6%: among participants with two or more pain sites, the effect estimate reduced substantially, for example, HR reduced from 1.25 (95% CI: 1.21 to 1.30; two pain sites) to 1.07 (95% CI: 1.01 to 1.11; two pain sites). INTERPRETATION: We found that higher number of pain sites was associated with increased risk of all-cause mortality compared to having no pain, and at least half of the association of chronic musculoskeletal pain with increased all-cause mortality may be accounted for by four mediators. FUNDING: Twins Research Australia