481 research outputs found
Sonically-enhanced widgets: comments on Brewster and Clarke, ICAD 1997
This paper presents a review of the research surrounding the paper âThe Design and Evaluation of a Sonically Enhanced Tool Paletteâ by Brewster and Clarke from ICAD 1997. A historical perspective is given followed by a discussion of how this work has fed into current developments in the area
Full potential LAPW calculation of electron momentum density and related properties of Li
Electron momentum density and Compton profiles in Lithium along , and directions are calculated using Full-Potential Linear
Augmented Plane Wave basis within generalized gradient approximation. The
profiles have been corrected for correlations with Lam-Platzman formulation
using self-consistent charge density. The first and second derivatives of
Compton profiles are studied to investigate the Fermi surface breaks. Decent
agreement is observed between recent experimental and our calculated values.
Our values for the derivatives are found to be in better agreement with
experiments than earlier theoretical results. Two-photon momentum density and
one- and two-dimensional angular correlation of positron annihilation radiation
are also calculated within the same formalism and including the
electron-positron enhancement factor.Comment: 11 pages, 7 figures TO appear in Physical Review
Dose-dependent effects of Allopurinol on human foreskin fibroblast cell and human umbilical vein endothelial cell under hypoxia
Allopurinol, an inhibitor of xanthine oxidase, has been used in clinical trials of patients with cardiovascular and chronic kidney disease. These are two pathologies with extensive links to hypoxia and activation of the transcription factor hypoxia inducible factor (HIF) family. Here we analysed the effects of allopurinol treatment in two different cellular models, and their response to hypoxia. We explored the dose-dependent effect of allopurinol on Human Foreskin Fibroblasts (HFF) and Human Umbilical Vein Endothelial Cells (HUVEC) under hypoxia and normoxia. Under normoxia and hypoxia, high dose allopurinol reduced the accumulation of HIF-1α protein in HFF and HUVEC cells. Allopurinol had only marginal effects on HIF-1α mRNA level in both cellular systems. Interestingly, allopurinol effects over the HIF system were independent of prolyl-hydroxylase activity. Finally, allopurinol treatment reduced angiogenesis traits in HUVEC cells in an in vitro model. Taken together these results indicate that high doses of allopurinol inhibits the HIF system and pro-angiogenic traits in cells
Wearable Haptic Devices for Gait Re-education by Rhythmic Haptic Cueing
This research explores the development and evaluation of wearable haptic devices for gait sensing and rhythmic haptic cueing in the context of gait re-education for people with neurological and neurodegenerative conditions. Many people with long-term neurological and neurodegenerative conditions such as Stroke, Brain Injury, Multiple Sclerosis or Parkinsonâs disease suffer from impaired walking gait pattern. Gait improvement can lead to better fluidity in walking, improved health outcomes, greater independence, and enhanced quality of life. Existing lab-based studies with wearable devices have shown that rhythmic haptic cueing can cause immediate improvements to gait features such as temporal symmetry, stride length, and walking speed. However, current wearable systems are unsuitable for self-managed use for in-the-wild applications with people having such conditions. This work aims to investigate the research question of how wearable haptic devices can help in long-term gait re-education using rhythmic haptic cueing. A longitudinal pilot study has been conducted with a brain trauma survivor, providing rhythmic haptic cueing using a wearable haptic device as a therapeutic intervention for a two-week period. Preliminary results comparing pre and post-intervention gait measurements have shown improvements in walking speed, temporal asymmetry, and stride length. The pilot study has raised an array of issues that require further study. This work aims to develop and evaluate prototype systems through an iterative design process to make possible the self-managed use of such devices in-the-wild. These systems will directly provide therapeutic intervention for gait re-education, offer enhanced information for therapists, remotely monitor dosage adherence and inform treatment and prognoses over the long-term. This research will evaluate the use of technology from the perspective of multiple stakeholders, including clinicians, carers and patients. This work has the potential to impact clinical practice nationwide and worldwide in neuro-physiotherapy
Mass-Losing Semiregular Variable Stars in Baade's Windows
By cross-correlating the results of two recent large-scale surveys, the
general properties of a well defined sample of semi-regular variable stars have
been determined. ISOGAL mid-infrared photometry and MACHO lightcurves are
assembled for approximately 300 stars in the Baade's Windows of low extinction
towards the Galactic bulge. These stars are mainly giants of late M spectral
type, evolving along the asymptotic giant branch (AGB). They are found to
possess a wide and continuous distribution of pulsation periods and to obey an
approximate log~period -- bolometric magnitude relation or set of such
relations.
Approximate mass-loss rates in the range of 1e-8 to 5e-7 M_sun per year are
derived from ISOGAL mid-infrared photometry and models of stellar spectra
adjusted for the presence of optically-thin circumstellar silicate dust.
Mass-loss rates depend on luminosity and pulsation period. Some stars lose mass
as rapidly as short-period Miras but do not show Mira-like amplitudes. A period
of 70 days or longer is a necessary but not a sufficient condition for mass
loss to occur.
For AGB stars in the mass-loss ranges that we observe, the functional
dependence of mass-loss rate on temperature and luminosity is found to be in
agreement with recent theoretical predictions. If we include our mass-loss
rates with a sample of extreme mass-losing AGB stars in the Large Magellanic
Cloud, we get the general result for AGB stars that mass-loss rate is
proportional to luminosity^{2.7}, valid for AGB stars with 10^{-8} to 10^{-4}
M_sun per year (Abridged).Comment: to appear in The Astrophysical Journal, 51 pages, 9 figures, 3
tables; table 1 will be available in machine-readable format at the
electronic Ap
Asteroseismology of old open clusters with Kepler: direct estimate of the integrated RGB mass loss in NGC6791 and NGC6819
Mass loss of red giant branch (RGB) stars is still poorly determined, despite
its crucial role in the chemical enrichment of galaxies. Thanks to the recent
detection of solar-like oscillations in G-K giants in open clusters with
Kepler, we can now directly determine stellar masses for a statistically
significant sample of stars in the old open clusters NGC6791 and NGC6819. The
aim of this work is to constrain the integrated RGB mass loss by comparing the
average mass of stars in the red clump (RC) with that of stars in the
low-luminosity portion of the RGB (i.e. stars with L <~ L(RC)). Stellar masses
were determined by combining the available seismic parameters numax and Dnu
with additional photometric constraints and with independent distance
estimates. We measured the masses of 40 stars on the RGB and 19 in the RC of
the old metal-rich cluster NGC6791. We find that the difference between the
average mass of RGB and RC stars is small, but significant (Delta M=0.09 +-
0.03 (random) +- 0.04 (systematic) Msun). Interestingly, such a small DeltaM
does not support scenarios of an extreme mass loss for this metal-rich cluster.
If we describe the mass-loss rate with Reimers' prescription, a first
comparison with isochrones suggests that the observed DeltaM is compatible with
a mass-loss efficiency parameter in the range 0.1 <~ eta <~ 0.3. Less stringent
constraints on the RGB mass-loss rate are set by the analysis of the ~ 2
Gyr-old NGC6819, largely due to the lower mass loss expected for this cluster,
and to the lack of an independent and accurate distance determination. In the
near future, additional constraints from frequencies of individual pulsation
modes and spectroscopic effective temperatures, will allow further stringent
tests of the Dnu and numax scaling relations, which provide a novel, and
potentially very accurate, means of determining stellar radii and masses.Comment: 13 pages, 7 figures, accepted for publication in MNRA
Circulating adrenomedullin estimates survival and reversibility of organ failure in sepsis: the prospective observational multinational Adrenomedullin and Outcome in Sepsis and Septic Shock-1 (AdrenOSS-1) study
Background: Adrenomedullin (ADM) regulates vascular tone and endothelial permeability during sepsis. Levels of circulating biologically active ADM (bio-ADM) show an inverse relationship with blood pressure and a direct relationship with vasopressor requirement. In the present prospective observational multinational Adrenomedullin and Outcome in Sepsis and Septic Shock 1 (, AdrenOSS-1) study, we assessed relationships between circulating bio-ADM during the initial intensive care unit (ICU) stay and short-term outcome in order to eventually design a biomarker-guided randomized controlled trial. Methods: AdrenOSS-1 was a prospective observational multinational study. The primary outcome was 28-day mortality. Secondary outcomes included organ failure as defined by Sequential Organ Failure Assessment (SOFA) score, organ support with focus on vasopressor/inotropic use, and need for renal replacement therapy. AdrenOSS-1 included 583 patients admitted to the ICU with sepsis or septic shock. Results: Circulating bio-ADM levels were measured upon admission and at day 2. Median bio-ADM concentration upon admission was 80.5 pg/ml [IQR 41.5-148.1 pg/ml]. Initial SOFA score was 7 [IQR 5-10], and 28-day mortality was 22%. We found marked associations between bio-ADM upon admission and 28-day mortality (unadjusted standardized HR 2.3 [CI 1.9-2.9]; adjusted HR 1.6 [CI 1.1-2.5]) and between bio-ADM levels and SOFA score (p < 0.0001). Need of vasopressor/inotrope, renal replacement therapy, and positive fluid balance were more prevalent in patients with a bio-ADM > 70 pg/ml upon admission than in those with bio-ADM †70 pg/ml. In patients with bio-ADM > 70 pg/ml upon admission, decrease in bio-ADM below 70 pg/ml at day 2 was associated with recovery of organ function at day 7 and better 28-day outcome (9.5% mortality). By contrast, persistently elevated bio-ADM at day 2 was associated with prolonged organ dysfunction and high 28-day mortality (38.1% mortality, HR 4.9, 95% CI 2.5-9.8). Conclusions: AdrenOSS-1 shows that early levels and rapid changes in bio-ADM estimate short-term outcome in sepsis and septic shock. These data are the backbone of the design of the biomarker-guided AdrenOSS-2 trial. Trial registration: ClinicalTrials.gov, NCT02393781. Registered on March 19, 2015
A Comparison of Computerized Chemical Models for Equilibrium Calculations in Aqueous Systems
A survey of computer programs which are currently being used to calculate the distribution of species in aqueous solutions, especially natural waters, has been made in order to 1) provide an inventory of available programs with a short description of their uses, 2) compare the consistency of their output for two given test solutions and 3) identify major weaknesses or problems encountered from their use. More than a dozen active programs which can be used for distribution of species and activity calculations for homogeneos equilibria among the major anions and cations of natural waters have been inventoried. Half of these programs can also accept several trace elements including Fe, Al, Mn, Cu, Ni, Zn, Cd, Pb, Ag, Hg, As, Ba, Sr, and B. Consistency between programs was evaluated by comparing the log of the molal concentrations of free ions and complexes for two test solutions: a hypothetical seawater analysis and a hypothetical river water analysis. Comparison of the free major ion concentrations in the river water test case shows excellent agreement for the major species. In the seawater test case there is less agreement and for both test cases the minor species commonly show orders of magnitude differences in concentrations. These differences primarily reflect differences in the thermodynamic data base of each chemical model although other factors such as activity coefficient calculations, redox assumptions, temperature corrections, alkalinity corrections and the number of complexes used all have an affect on the output
Rabies, Still Neglected after 125 Years of Vaccination
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