2,413 research outputs found

    11-interval PFG pulse sequence for improved measurement of fast velocities of fluids with high diffusivity in systems with short T2(∗).

    Get PDF
    Magnetic resonance (MR) was used to measure SF6 gas velocities in beds filled with particles of 1.1 mm and 0.5 mm in diameter. Four pulse sequences were tested: a traditional spin echo pulse sequence, the 9-interval and 13-interval pulse sequence of Cotts et al. (1989) and a newly developed 11-interval pulse sequence. All pulse sequences measured gas velocity accurately in the region above the particles at the highest velocities that could be achieved (up to 0.1 ms(-1)). The spin echo pulse sequence was unable to measure gas velocity accurately in the bed of particles, due to effects of background gradients, diffusivity and acceleration in flow around particles. The 9- and 13-interval pulse sequence measured gas velocity accurately at low flow rates through the particles (expected velocity <0.06 ms(-1)), but could not measure velocity accurately at higher flow rates. The newly developed 11-interval pulse sequence was more accurate than the 9- and 13-interval pulse sequences at higher flow rates, but for velocities in excess of 0.1 ms(-1) the measured velocity was lower than the expected velocity. The increased accuracy arose from the smaller echo time that the new pulse sequence enabled, reducing selective attenuation of signal from faster moving nuclei.CMB acknowledges the Gates Cambridge Trust for funding his research.This is the author accepted manuscript. The final version is available from Elsevier via http://dx.doi.org/10.1016/j.jmr.2016.01.02

    Honeaite, a new gold-thallium-telluride from the Eastern Goldfields, Yilgarn Craton, Western Australia

    Get PDF
    Honeaite, ideal formula Au3TlTe2, is a new mineral from the late Archaean Karonie gold deposit, Eastern Goldfields province, Western Australia. Honeaite is found with native gold, tellurobismuthite, petzite, hessite, calaverite, melonite, mattagamite, frohbergite, altaite, pyrrhotite and molybdenite. These minerals are concentrated in microvughs and microfractures mainly within areas of prehnite alteration of amphibolite. The mineralisation appears to have been deposited under greenschistfacies conditions at lower temperatures than most gold deposits in the Eastern Goldfields. Single-crystal X-ray studies identified the structure of honeaite as orthorhombic, space group Pbcm, and unit cell parameters a = 8.9671(4) Å, b = 8.8758(4) Å, c = 7.8419(5) Å, V = 624.14(6) Å3 (Z = 4). The strongest reflections of the calculated powder X-ray diffraction pattern are [d in Å (I rel)(hkl)]: 2.938(100)(022), 2.905 (39,8)(322, 411), 2.989 (31)(300), 2.833 (23)(310), 1.853 (17)(332). Electron-microprobe analysis (EDS mode) gave (wt%) Au 56.33, Tl 19.68, Te 24.30, total 100.31, leading to an empirical formula (based on 2 Te apfu) of Au3.00Tl1.01Te2.00. Honeaite is black with a metallic lustre and no observed cleavage. The calculated density is 11.18 g/cm3. In reflected plane-polarized light it is slightly bluish grey. Between crossed polars it is weakly anisotropic with dark brown to dark blue rotation tints. Reflectance values in air and in oil are given. Honeaite is named after the late Russell M. Honea (1929–2002).© 2016 E. Schweizerbart'sche Verlagsbuchhandlung, D-70176 Stuttgart. This document is the author's final accepted version of the journal article. You are advised to consult the publisher's version if you wish to cite from it

    A controlled trial of natalizumab for relapsing multiple sclerosis.

    Get PDF
    Background: In patients with multiple sclerosis, inflammatory brain lesions appear to arise from autoimmune responses involving activated lymphocytes and monocytes. The glycoprotein (alpha)(sub 4) integrin is expressed on the surface of these cells and plays a critical part in their adhesion to the vascular endothelium and migration into the parenchyma. Natalizumab is an (alpha)(sub 4) integrin antagonist that reduced the development of brain lesions in experimental models and in a preliminary study of patients with multiple sclerosis.Methods: In a randomized, double-blind trial, we randomly assigned a total of 213 patients with relapsing-remitting or relapsing secondary progressive multiple sclerosis to receive 3 mg of intravenous natalizumab per kilogram of body weight (68 patients), 6 mg per kilogram (74 patients), or placebo (71 patients) every 28 days for 6 months. The primary end point was the number of new brain lesions on monthly gadolinium-enhanced magnetic resonance imaging during the six-month treatment period. Clinical outcomes included relapses and self-reported well-being.Results: There were marked reductions in the mean number of new lesions in both natalizumab groups: 9.6 per patient in the placebo group, as compared with 0.7 in the group given 3 mg of natalizumab per kilogram (P<0.001) and 1.1 in the group given 6 mg of natalizumab per kilogram (P<0.001). Twenty-seven patients in the placebo group had relapses, as compared with 13 in the group given 3 mg of natalizumab per kilogram (P=0.02) and 14 in the group given 6 mg of natalizumab per kilogram (P=0.02). The placebo group reported a slight worsening in well-being (a mean decrease of 1.38 mm on a 100-mm visual-analogue scale), whereas the natalizumab groups reported an improvement (mean increase of 9.49 mm in the group given 3 mg of natalizumab per kilogram and 6.21 mm in the group given 6 mg of natalizumab per kilogram).Conclusions: In a placebo-controlled trial, treatment with natalizumab led to fewer inflammatory brain lesions and fewer relapses over a six-month period in patients with relapsing multiple sclerosis

    Scintillator-based ion beam profiler for diagnosing laser-accelerated ion beams

    Get PDF
    Next generation intense, short-pulse laser facilities require new high repetition rate diagnostics for the detection of ionizing radiation. We have designed a new scintillator-based ion beam profiler capable of measuring the ion beam transverse profile for a number of discrete energy ranges. The optical response and emission characteristics of four common plastic scintillators has been investigated for a range of proton energies and fluxes. The scintillator light output (for 1 MeV > Ep < 28 MeV) was found to have a non-linear scaling with proton energy but a linear response to incident flux. Initial measurements with a prototype diagnostic have been successful, although further calibration work is required to characterize the total system response and limitations under the high flux, short pulse duration conditions of a typical high intensity laser-plasma interaction

    Predictors of treatment response in young people at ultra-high risk for psychosis who received long-chain omega-3 fatty acids

    Get PDF
    Previous efforts in the prospective evaluation of individuals who experience attenuated psychotic symptoms have attempted to isolate mechanisms underlying the onset of full-threshold psychotic illness. In contrast, there has been little research investigating specific predictors of positive outcomes. In this study, we sought to determine biological and clinical factors associated with treatment response, here indexed by functional improvement in a pre-post examination of a 12-week randomized controlled intervention in individuals at ultra-high risk (UHR) for psychosis. Participants received either long-chain omega-3 (&omega;-3) polyunsaturated fatty acids (PUFAs) or placebo. To allow the determination of factors specifically relevant to each intervention, and to be able to contrast them, both treatment groups were investigated in parallel. Univariate linear regression analysis indicated that higher levels of erythrocyte membrane &alpha;-linolenic acid (ALA; the parent fatty acid of the &omega;-3 family) and more severe negative symptoms at baseline predicted subsequent functional improvement in the treatment group, whereas less severe positive symptoms and lower functioning at baseline were predictive in the placebo group. A multivariate machine learning analysis, known as Gaussian Process Classification (GPC), confirmed that baseline fatty acids predicted response to treatment in the &omega;-3 PUFA group with high levels of sensitivity, specificity and accuracy. In addition, GPC revealed that baseline fatty acids were predictive in the placebo group. In conclusion, our investigation indicates that UHR patients with higher levels of ALA may specifically benefit from &omega;-3 PUFA supplementation. In addition, multivariate machine learning analysis suggests that fatty acids could potentially be used to inform prognostic evaluations and treatment decisions at the level of the individual. Notably, multiple statistical analyses were conducted in a relatively small sample, limiting the conclusions that can be drawn from what we believe to be a first-of-its-kind study. Additional studies with larger samples are therefore needed to evaluate the generalizability of these findings

    Characterization of infectious retroviral pseudotype particles bearing hepatitis C virus glycoproteins

    Get PDF
    The recent development of infectious retroviral pseudotypes bearing hepatitis C virus (HCV) glycoproteins represents an opportunity to study the functionally active form of the HCV E1 and E2 glycoproteins. In the culture supernatant of cells producing HCV retroviral pseudotypes, the majority of E2 was not associated with infectious particles and failed to sediment on sucrose gradients. The E2 that was incorporated into infectious particles appeared as a triplet of diffuse bands at 60, 70, and 90 kDa. Similarly, three major forms of E1 were incorporated into the pseudotype particles, migrating at 33, 31, and 25 kDa. Endoglycosidase H (endo-H) treatment of particles demonstrated that the incorporated E1 was partially or completely sensitive to digestion. In contrast, the majority of the incorporated E2 was endo-H resistant. Purified pseudotype particles were found to contain both disulfide-linked aggregates and nonaggregated E1 and E2. HCV pseudotypes generated from cells expressing E1E2p7 showed similar heterogeneity in the incorporated glycoproteins and were of comparable infectivity to those generated by expression of E1E2. Our results demonstrate the heterogenous nature of E1 and E2 incorporated into retroviral pseudotypes and highlight the difficulty in identifying forms of the HCV glycoproteins that initiate infection

    Men’s Physical Activity and Sleep Following a Workplace Health Intervention: Findings from the POWERPLAY STEP Up challenge

    Get PDF
    The workplace provides an important delivery point for health promotion, yet many programs fail to engage men. A gender-sensitive 8-week team challenge-based intervention targeting increased physical activity was delivered at a petrochemical worksite. The purpose of this study was to examine men’s pre–post physical activity and sleep following the intervention, as well as to explore program acceptability and gather men’s recommendations for health promotion. Pre–post surveys assessed physical activity, sleep, program exposure, acceptability, and suggestions for continued support. Overall, 328 men completed baseline surveys and 186 (57%) completed follow-up surveys. Walking increased by 156.5 min/week, 95% confidence interval (61.2, 251.8), p = .001. Men with higher program exposure increased moderate and vigorous activity 49.4 min more than those with low exposure (p = .026). Sleep duration and quality were higher postintervention, though changes were modest. Program acceptability was high as was intention to maintain physical activity. Men’s suggestions to enable physical activity involved workplace practices/resources, reducing workload, and leadership support. These findings suggest that a gender-sensitive physical activity workplace intervention showed promise for improving physical activity and sleep among men. The men’s suggestions reflected workplace health promotion strategies, reinforcing the need for employers to support ongoing health promotion efforts

    Exploring CBD retail performance, recovery and resilience of a smart city following COVID-19

    Get PDF
    The city of Christchurch, New Zealand, incurred significant damage due to a series of earthquakes in 2010 and 2011. The city had, by the late 2010s, regained economic and social normalcy after a sustained period of rebuilding and economic recovery. Through the concerted rebuilding effort, a modern central business district (CBD) with redesigned infrastructure and amenities was developed. The Christchurch rebuild was underpinned by a commitment of urban planners to an open and connected city, including the use of innovative technologies to gather, use and share data. As was the case elsewhere, the COVID-19 pandemic brought about significant disruptions to social and economic life in Christchurch. Border closures, lockdowns, trading limitations and other restrictions on movement led to changes in traditional consumer behaviors and affected the retail sector’s resilience. In this study, we used CBD pedestrian traffic data gathered from various locations to predict changes in retail spending and identify recovery implications through the lens of retail resilience. We found that the COVID-19 pandemic and its related lockdowns have driven a substantive change in the behavioral patterns of city users. The implications for resilient retail, sustainable policy and further research are explored
    corecore