303 research outputs found
High Bone Mass is associated with bone-forming features of osteoarthritis in non-weight bearing joints independent of body mass index
Objectives: High Bone Mass (HBM) is associated with (a) radiographic knee osteoarthritis (OA), partly mediated by increased BMI, and (b) pelvic enthesophytes and hip osteophytes, suggestive of a bone-forming phenotype. We aimed to establish whether HBM is associated with radiographic features of OA in non weight-bearing (hand) joints, and whether such OA demonstrates a bone-forming phenotype. Methods: HBM cases (BMD Z-scores â„+3.2) were compared with family controls. A blinded assessor graded all PA hand radiographs for: osteophytes (0-3), joint space narrowing (JSN)(0-3), subchondral sclerosis (0-1), at the index Distal Interphalangeal Joint (DIPJ) and 1st Carpometacarpal Joint (CMCJ), using an established atlas. Analyses used a random effects logistic regression model, adjusting a priori for age and gender. Mediating roles of BMI and bone turnover markers (BTMs) were explored by further adjustment. Results: 314 HBM cases (mean age 61.1years, 74% female) and 183 controls (54.3years, 46% female) were included. Osteophytes (gradeâ„1) were more common in HBM (DIPJ: 67% vs. 45%, CMCJ: 69% vs. 50%), with adjusted OR [95% CI] 1.82 [1.11, 2.97], p=0.017 and 1.89 [1.19, 3.01], p=0.007 respectively; no differences were seen in JSN. Further adjustment for BMI failed to attenuate ORs for osteophytes in HBM cases vs. controls; DIPJ 1.72 [1.05, 2.83], p=0.032, CMCJ 1.76 [1.00, 3.06], p=0.049. Adjustment for BTMs (concentrations lower amongst HBM cases) did not attenuate ORs. Conclusions: HBM is positively associated with OA in non weight-bearing joints, independent of BMI. HBMassociated OA is characterised by osteophytes, consistent with a bone-forming phenotype, rather than JSN reflecting cartilage loss. Systemic factors (e.g. genetic architecture) which govern HBM may also increase bone-forming OA risk
Study of Dipole Resonance Strength in 12-C via the Reactions 12-C(pol.p,p'c)
This research was sponsored by the National Science Foundation Grant NSF PHY-931478
Photoaquation mechanism of hexacyanoferrate(II) ions: ultrafast 2D UV and transient visible and IR spectroscopies
Ferrous iron(II) hexacyanide in aqueous solutions is known to undergo photoionization and photoaquation reactions depending on the excitation wavelength. To investigate this wavelength dependence, we implemented ultrafast two-dimensional UV transient absorption spectroscopy, covering a range from 280 to 370 nm in both excitation and probing, along with UV pump/visible probe or time-resolved infrared (TRIR) transient absorption spectroscopy and density functional theory (DFT) calculations. As far as photoaquation is concerned, we find that excitation of the molecule leads to ultrafast intramolecular relaxation to the lowest triplet state of the [Fe(CN)6]4â complex, followed by its dissociation into CNâ and [Fe(CN)5]3â fragments and partial geminate recombination, all within <0.5 ps. The subsequent time evolution is associated with the [Fe(CN)5]3â fragment going from a triplet square pyramidal geometry, to the lowest triplet trigonal bipyramidal state in 3â4 ps. This is the precursor to aquation, which occurs in âŒ20 ps in H2O and D2O solutions, forming the [Fe(CN)5(H2O/D2O)]3â species, although some aquation also occurs during the 3â4 ps time scale. The aquated complex is observed to be stable up to the microsecond time scale. For excitation below 310 nm, the dominant channel is photooxidation with a minor aquation channel. The photoaquation reaction shows no excitation wavelength dependence up to 310 nm, that is, it reflects a Kasha Rule behavior. In contrast, the photooxidation yield increases with decreasing excitation wavelength. The various intermediates that appear in the TRIR experiments are identified with the help of DFT calculations. These results provide a clear example of the energy dependence of various reactive pathways and of the role of spin-states in the reactivity of metal complexes
Fertility, Living Arrangements, Care and Mobility
There are four main interconnecting themes around which the contributions in this book are based. This introductory chapter aims to establish the broad context for the chapters that follow by discussing each of the themes. It does so by setting these themes within the overarching demographic challenge of the twenty-first century â demographic ageing. Each chapter is introduced in the context of the specific theme to which it primarily relates and there is a summary of the data sets used by the contributors to illustrate the wide range of cross-sectional and longitudinal data analysed
Field Measurements of Terrestrial and Martian Dust Devils
Surface-based measurements of terrestrial and martian dust devils/convective vortices provided from mobile and stationary platforms are discussed. Imaging of terrestrial dust devils has quantified their rotational and vertical wind speeds, translation speeds, dimensions, dust load, and frequency of occurrence. Imaging of martian dust devils has provided translation speeds and constraints on dimensions, but only limited constraints on vertical motion within a vortex. The longer mission durations on Mars afforded by long operating robotic landers and rovers have provided statistical quantification of vortex occurrence (time-of-sol, and recently seasonal) that has until recently not been a primary outcome of more temporally limited terrestrial dust devil measurement campaigns. Terrestrial measurement campaigns have included a more extensive range of measured vortex parameters (pressure, wind, morphology, etc.) than have martian opportunities, with electric field and direct measure of dust abundance not yet obtained on Mars. No martian robotic mission has yet provided contemporaneous high frequency wind and pressure measurements. Comparison of measured terrestrial and martian dust devil characteristics suggests that martian dust devils are larger and possess faster maximum rotational wind speeds, that the absolute magnitude of the pressure deficit within a terrestrial dust devil is an order of magnitude greater than a martian dust devil, and that the time-of-day variation in vortex frequency is similar. Recent terrestrial investigations have demonstrated the presence of diagnostic dust devil signals within seismic and infrasound measurements; an upcoming Mars robotic mission will obtain similar measurement types
Herschel observations of EXtra-Ordinary Sources (HEXOS): Observations of H2O and its isotopologues towards Orion KL
We report the detection of more than 48 velocity-resolved ground rotational state transitions of H 16
2 O, H 18
2 O, and H 17
2 O â most for the first time
â in both emission and absorption toward Orion KL using Herschel/HIFI. We show that a simple fit, constrained to match the known emission
and absorption components along the line of sight, is in excellent agreement with the spectral profiles of all the water lines. Using the measured
H 18
2 O line fluxes, which are less affected by line opacity than their H 16
2 O counterparts, and an escape probability method, the column densities
of H 18
2 O associated with each emission component are derived. We infer total water abundances of 7.4 Ă 10â5, 1.0Ă 10â5, and 1.6 Ă 10â5 for the
plateau, hot core, and extended warm gas, respectively. In the case of the plateau, this value is consistent with previous measures of the Orion-KL
water abundance as well as those of other molecular outflows. In the case of the hot core and extended warm gas, these values are somewhat higher
than water abundances derived for other quiescent clouds, suggesting that these regions are likely experiencing enhanced water-ice sublimation
from (and reduced freeze-out onto) grain surfaces due to the warmer dust in these sources
Herschel observations of deuterated water towards Sgr B2(M)
Observations of HDO are an important complement for studies of water, because they give strong constraints on the formation processes â grain
surfaces versus energetic process in the gas phase, e.g. in shocks. The HIFI observations of multiple transitions of HDO in Sgr B2(M) presented
here allow the determination of the HDO abundance throughout the envelope, which has not been possible before with ground-based observations
only. The abundance structure has been modeled with the spherical Monte Carlo radiative transfer code RATRAN, which also takes radiative
pumping by continuum emission from dust into account. The modeling reveals that the abundance of HDO rises steeply with temperature from
a low abundance (2.5 Ă 10â11) in the outer envelope at temperatures below 100 K through a medium abundance (1.5 Ă 10â9) in the inner
envelope/outer core at temperatures between 100 and 200 K, and finally a high abundance ( 3.5 Ă 10â9) at temperatures above 200 K in the hot
core
Herschel observations of EXtra-Ordinary Sources (HEXOS): Detection of hydrogen fluoride in absorption towards Orion KL
We report a detection of the fundamental rotational transition of hydrogen fluoride in absorption towards Orion KL using Herschel/HIFI. After the
removal of contaminating features associated with common molecules (âweedsâ), the HF spectrum shows a P-Cygni profile, with weak redshifted
emission and strong blue-shifted absorption, associated with the low-velocity molecular outflow. We derive an estimate of 2.9 Ă 1013 cmâ2 for the
HF column density responsible for the broad absorption component. Using our best estimate of the H2 column density within the low-velocity
molecular outflow, we obtain a lower limit of âŒ1.6 Ă 10â10 for the HF abundance relative to hydrogen nuclei, corresponding to âŒ0.6% of the solar
abundance of fluorine. This value is close to that inferred from previous ISO observations of HF J = 2â1 absorption towards Sgr B2, but is in
sharp contrast to the lower limit of 6 Ă 10â9 derived by Neufeld et al. for cold, foreground clouds on the line of sight towards G10.6-0.4
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