190 research outputs found

    CO oxidation on a single Pd atom supported on magnesia

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    The oxidation of CO on single Pd atoms anchored to MgO(100) surface oxygen vacancies is studied with temperature-programmed-reaction mass-spectrometry and infrared spectroscopy. In one-heating-cycle experiments CO2_2, formed from O2_2 and CO preadsorbed at 90 K, is detected at 260 K and 500 K. Ab-initio simulations suggest two reaction routes, with Pd(CO)2_2O2_2 and Pd(CO3_3)CO found as precursors for the low and high temperature channels, respectively. Both reactions result in annealing of the vacancy and induce migration and coalescence of the remaining Pd-CO to form larger clusters.Comment: 4 pages, 3 figures, scheduled for publication in PRL 18 June 200

    Effects of Concurrent Resistance and Aerobic Training on Load-Bearing Performance and the Army Physical Fitness Test

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    The purpose of this research was to determine the effects of high intensity endurance training (ET) and resistance training (RT) alone and in combination on various military tasks. Thirty-five male soldiers were randomly assigned to one of four training groups: total body resistance training plus endurance training (RT + ET), upper body resistance training plus endurance training [UB + ET), RT only, and ET only. Training was performed 4 days per week for 12 weeks. Testing occurred before and after the 12-week training regimen. All groups significantly improved push-up performance, whereas only the RT + ET group did not improve sit-up performance. The groups that included ET significantly decreased 2-mile run time, however, only RT + ET and UB + ET showed improved loaded 2-mile run time. Leg power increased for groups that included lower body strengthening exercises (RT and RT + ET). Army Physical Fitness Test performance, loaded running, and leg power responded positively to training, however, it appears there is a high degree of specificity when concurrent training regimens are implemented

    Comparing ischaemic stroke in six European countries. The EuroHOPE register study.

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    BACKGROUND AND PURPOSE: The incidence of hospitalizations, treatment and case fatality of ischaemic stroke were assessed utilizing a comprehensive multinational database to attempt to compare the healthcare systems in six European countries, aiming also to identify the limitations and make suggestions for future improvements in the between-country comparisons. METHODS: National registers of hospital discharges for ischaemic stroke identified by International Classification of Diseases codes 433-434 (ICD-9) and code I63 (ICD-10), medication purchases and mortality were linked at the patient level in each of the participating countries and regions: Finland, Hungary, Italy, the Netherlands, Scotland and Sweden. Patients with an index admission in 2007 were followed for 1 year. RESULTS: In all, 64 170 patients with a disease code for ischaemic stroke were identified. The number of patients registered per 100 000 European standard population ranged from 77 in Scotland to 407 in Hungary. Large differences were observed in medication use. The age- and sex-adjusted all-cause case fatality amongst hospitalized patients at 1 year from stroke was highest in Hungary at 31.0% (95% confidence interval 30.5-31.5). Regional differences in age- and sex-adjusted 1-year case fatality within countries were largest in Hungary (range 23.6%-37.6%) and smallest in the Netherlands (20.5%-27.3%). CONCLUSIONS: It is feasible to link population-wide register data amongst European countries to describe incidence of hospitalizations, treatment patterns and case fatality of ischaemic stroke on a national level. However, the coverage and validity of administrative register data for ischaemic stroke should be developed further, and population-based and clinical stroke registers should be created to allow better control of case mix

    Efficacy of progressive aquatic resistance training for tibiofemoral cartilage in postmenopausal women with mild knee osteoarthritis : a randomised controlled trial

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    Objective: To study the efficacy of aquatic resistance training on biochemical composition of tibiofemoral cartilage in postmenopausal women with mild knee osteoarthritis (OA). Design: Eighty seven volunteer postmenopausal women, aged 60-68 years, with mild knee OA (Kellgren-Lawrence grades I/II and knee pain) were recruited and randomly assigned to an intervention (n = 43) and control (n = 44) group. The intervention group participated in 48 supervised aquatic resistance training sessions over 16 weeks while the control group maintained usual level of physical activity. The biochemical composition of the medial and lateral tibiofemoral cartilage was estimated using single-slice transverse relaxation time (T2) mapping and delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC index). Secondary outcomes were cardiorespiratory fitness, isometric knee extension and flexion force and knee injury and OA outcome (KOOS) questionnaire. Results: After 4-months aquatic training, there was a significant decrease in both T2 -1.2 ms (95% confidence interval (CI): -2.3 to -0.1, P = 0.021) and dGEMRIC index -23 ms (-43 to -3, P = 0.016) in the training group compared to controls in the full thickness posterior region of interest (ROI) of the medial femoral cartilage. Cardiorespiratory fitness significantly improved in the intervention group by 9.8% (P = 0.010). Conclusions: Our results suggest that, in postmenopausal women with mild knee OA, the integrity of the collagen-interstitial water environment (T2) of the tibiofemoral cartilage may be responsive to low shear and compressive forces during aquatic resistance training. More research is required to understand the exact nature of acute responses in dGEMRIC index to this type of loading. Further, aquatic resistance training improves cardiorespiratory fitness. (C) 2016 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.Peer reviewe

    Reversed anisotropies and thermal contraction of FCC (110) surfaces

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    The observed anisotropies of surface vibrations for unreconstructed FCC metal (110) surfaces are often reversed from the "common sense" expectation. The source of these reversals is investigated by performing ab initio density functional theory calculations to obtain the surface force constant tensors for Ag(110), Cu(110) and Al(110). The most striking result is a large enhancement in the coupling between the first and third layers of the relaxed surface, which strongly reduces the amplitude of out-of-plane vibrations of atoms in the first layer. This also provides a simple explanation for the thermal contraction of interlayer distances. Both the anisotropies and the thermal contraction arise primarily as a result of the bond topology, with all three (110) surfaces showing similar behavior.Comment: 13 pages, in revtex format, plus 1 postscript figur

    Mechanical properties and formation mechanisms of a wire of single gold atoms

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    A scanning tunneling microscope (STM) supplemented with a force sensor is used to study the mechanical properties of a novel metallic nanostructure: a freely suspended chain of single gold atoms. We find that the bond strength of the nanowire is about twice that of a bulk metallic bond. We perform ab initio calculations of the force at chain fracture and compare quantitatively with experimental measurements. The observed mechanical failure and nanoelastic processes involved during atomic wire fabrication are investigated using molecular dynamics (MD) simulations, and we find that the total effective stiffness of the nanostructure is strongly affected by the detailed local atomic arrangement at the chain bases.Comment: To be published in Phys. Rev. Lett. 4 pages with 3 figure

    Aromaticity in a Surface Deposited Cluster: Pd4_4 on TiO2_2 (110)

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    We report the presence of \sigma-aromaticity in a surface deposited cluster, Pd4_4 on TiO2_2 (110). In the gas phase, Pd4_4 adopts a tetrahedral structure. However, surface binding promotes a flat, \sigma-aromatic cluster. This is the first time aromaticity is found in surface deposited clusters. Systems of this type emerge as a promising class of catalyst, and so realization of aromaticity in them may help to rationalize their reactivity and catalytic properties, as a function of cluster size and composition.Comment: 4 pages, 3 figure

    Mortality and Length of Stay of Very Low Birth Weight and Very Preterm Infants: A EuroHOPE Study

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    The objective of this paper was to compare health outcomes and hospital care use of very low birth weight (VLBW), and very preterm (VLGA) infants in seven European countries. Analysis was performed on linkable patient-level registry data from seven European countries between 2006 and 2008 (Finland, Hungary, Italy (the Province of Rome), the Netherlands, Norway, Scotland, and Sweden). Mortality and length of stay (LoS) were adjusted for differences in gestational age (GA), sex, intrauterine growth, Apgar score at five minutes, parity and multiple births. The analysis included 16,087 infants. Both the 30-day and one-year adjusted mortality rates were lowest in the Nordic countries (Finland, Sweden and Norway) and Scotland and highest in Hungary and the Netherlands. For survivors, the adjusted average LoS during the first year of life ranged from 56 days in the Netherlands and Scotland to 81 days in Hungary. There were large differences between European countries in mortality rates and LoS in VLBW and VLGA infants. Substantial data linkage problems were observed in most countries due to inadequate identification procedures at birth, which limit data validity and should be addressed by policy makers across Europe.</p

    A structured review of long-term care demand modelling

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    Long-term care (LTC) represents a significant and substantial proportion of healthcare spends across the globe. Its main aim is to assist individuals suffering with more or more chronic illnesses, disabilities or cognitive impairments, to carry out activities associated with daily living. Shifts in several economic, demographic and social factors have raised concerns surrounding the sustainability of current systems of LTC. Substantial effort has been put into modelling the LTC demand process itself so as to increase understanding of the factors driving demand for LTC and its related services. Furthermore, such modeling efforts have also been used to plan the operation and future composition of the LTC system itself. The main aim of this paper is to provide a structured review of the literature surrounding LTC demand modeling and any such industrial application, whilst highlighting any potential direction for future researchers
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