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| 2. |
- Corrado, D., et al.
(författare)
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Cardiovascular pre-participation screening of young competitive athletes for prevention of sudden death: proposal for a common European protocol. Consensus Statement of the Study Group of Sport Cardiology of the Working Group of Cardiac Rehabilitation and Exercise Physiology and the Working Group of Myocardial and Pericardial Diseases of the European Society of Cardiology
- 2005
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Ingår i: Eur Heart J. ; 26:5, s. 516-24
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Tidskriftsartikel (refereegranskat)abstract
- The 1996 American Heart Association consensus panel recommendations stated that pre-participation cardiovascular screening for young competitive athletes is justifiable and compelling on ethical, legal, and medical grounds. The present article represents the consensus statement of the Study Group on Sports Cardiology of the Working Group on Cardiac Rehabilitation and Exercise Physiology and the Working Group on Myocardial and Pericardial diseases of the European Society of Cardiology, which comprises cardiovascular specialists and other physicians from different European countries with extensive clinical experience with young competitive athletes, as well as with pathological substrates of sudden death. The document takes note of the 25-year Italian experience on systematic pre-participation screening of competitive athletes and focuses on relevant issues, mostly regarding the relative risk, causes, and prevalence of sudden death in athletes; the efficacy, feasibility, and cost-effectiveness of population-based pre-participation cardiovascular screening; the key role of 12-lead ECG for identification of cardiovascular diseases such as cardiomyopathies and channelopathies at risk of sudden death during sports; and the potential of preventing fatal events. The main purpose of the consensus document is to reinforce the principle of the need for pre-participation medical clearance of all young athletes involved in organized sports programmes, on the basis of (i) the proven efficacy of systematic screening by 12-lead ECG (in addition to history and physical examination) to identify hypertrophic cardiomyopathy-the leading cause of sports-related sudden death-and to prevent athletic field fatalities; (ii) the potential screening ability in detecting other lethal cardiovascular diseases presenting with ECG abnormalities. The consensus document recommends the implementation of a common European screening protocol essentially based on 12-lead ECG.
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| 3. |
- Jiang, A., et al.
(författare)
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Theoretical study of the thermal behaviour of free and alumina-supported Fe-C nanoparticles
- 2007
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Ingår i: Physical Review B Condensed Matter. - : American Physical Society. - 0163-1829 .- 1095-3795. ; 75:20
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Tidskriftsartikel (refereegranskat)abstract
- The thermal behavior of free and alumina-supported iron-carbon nanoparticles is investigated via molecular-dynamics simulations, in which the effect of the substrate is treated with a simple Morse potential fitted to ab initio data. We observe that the presence of the substrate raises the melting temperature of medium and large Fe1-xCx nanoparticles (x=0-0.16, N=80-1000, nonmagic numbers) by 40-60 K; it also plays an important role in defining the ground state of smaller Fe nanoparticles (N=50-80). The main focus of our study is the investigation of Fe-C phase diagrams as a function of the nanoparticle size. We find that as the cluster size decreases in the 1.1-1.6-nm-diameter range, the eutectic point shifts significantly not only toward lower temperatures, as expected from the Gibbs-Thomson law, but also toward lower concentrations of C. The strong dependence of the maximum C solubility on the Fe-C cluster size may have important implications for the catalytic growth of carbon nanotubes by chemical-vapor deposition.
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| 5. |
- Caponi, S., et al.
(författare)
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The Debye-Waller factor approaching the glass-transition temperature in phosphate glasses
- 2006
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Ingår i: Journal of Non-Crystalline Solids. - : Elsevier BV. - 0022-3093. ; 352:42-49 SPEC. ISS., s. 4577-4582
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Tidskriftsartikel (refereegranskat)abstract
- The temperature dependence of the mean square displacement, 〈u2〉, calculated by elastic neutron scattering for two phosphate glasses, (AgI)x(AgPO3)1-x with x = 0.3, 0.55, is analysed. The studied samples are probed in a wide range of temperatures going from a few tens of K up to the glass transition temperature and well into the undercooled liquid state. In the low temperature regime a solid like behaviour appears, showing a linear temperature dependence of the Debye-Waller factor, while around Tg the onset of a pronounced increase of 〈u2〉 is observed. The temperature dependence of the normalized elastic intensity and the drawn out Debye-Waller factor are fitted and analyzed by the theoretical previsions of Mode Coupling Theory finding a good agreement. © 2006 Elsevier B.V. All rights reserved.
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| 6. |
- Martinelli, Anna, 1978, et al.
(författare)
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Structural analysis of PVA-based proton conducting membranes
- 2006
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Ingår i: Solid State Ionics. - : Elsevier BV. - 0167-2738. ; 177:26-32, s. 2431-2435
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Tidskriftsartikel (refereegranskat)abstract
- We have synthesized and characterized a new family of proton conducting membranes based on cross-linked poly(vinyl alcohol), PVA, and functionalized silica filler. Glutaraldehyde, GLA, was used as the cross-linking agent in order to improve chemical and thermal stabilities. The functionalization of the silica particles is such that terminal -SO 3 H groups are formed during membrane preparation, thus possibly providing additional mobile protons. We find that the crystallinity of the PVA-based membranes is enhanced by the presence of the functionalized silica particles, whereas it is reduced by means of cross-linking. The thermal stability of the ternary system PVA:GLA:silica is improved due to the additive contribution of GLA and silica. The conductivity of membranes swelled in a sulfuric acid solution was found to be of the order of 10 - 1 S cm - 1 . © 2006 Elsevier B.V. All rights reserved.
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| 7. |
- Ahmed, Istaq, 1972, et al.
(författare)
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Crystal structure and proton conductivity of BaZr0.9Sc0
- 2008
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Ingår i: Journal of the American Ceramic Society. - : Wiley. - 0002-7820 .- 1551-2916. ; 91:9, s. 3039-3044
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Tidskriftsartikel (refereegranskat)abstract
- Solid-state sintering has been used to prepare the perovskite BaZr0.9Sc0.1O3-delta. Analysis of X-ray powder diffraction data shows that an increase of the unit cell parameter, a, was observed after deuteration. Rietveld analysis of room-temperature neutron powder diffraction data confirmed cubic symmetry (space group Pm-3m). Dynamic thermogravimetric analysis indicates that the hydration process occurs below 335 degrees C and approximately 58% of the theoretical number of protonic defects can be filled. The presence of protons/deutrons is seen from the strong O-H/O-D stretch band in the infrared spectrum of the hydrated/deuterated samples. The proton conductivity of a prehydrated sample was investigated under dry and wet Ar atmospheres
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| 8. |
- Ahmed, Istaq, 1972, et al.
(författare)
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Structural study and proton conductivity of BaZr0.90Ga0.10O2.95
- 2006
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Ingår i: Advances of Solid Oxide Fuel Cells II, Ceramic Engineering and Science Proceedings. - Hoboken, NJ, USA : John Wiley & Sons, Inc.. ; 27:4, s. 105-117
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Tidskriftsartikel (refereegranskat)abstract
- Traditional solid state sintering has been used to prepare the perovskite BaZr0.9Ga0.1O2.95. Analysis of X-ray powder diffraction data shows that a decrease of the unit cell parameter a was observed compared to the undoped BaZrO3, which confirms successful substitution of Ga3+ for Zr4+ at the B site. Rietveld analysis of room temperature neutron powder diffraction data confirmed cubic symmetry (space group Pm-3m) for both as- prepared and deuterated BaZr0.90Ga0.10O2.95 samples. The strong O-H stretch band (2500-3500 cm−1) in the infrared absorbance spectrum clearly manifests the presence of protons in the pre-hydrated material. The bulk and total conductivities of prehydrated BaZr0.9Ga0.1O2.95 are 1.17 × 10−5 and 3.55 × 10−6 Scm−1, respectively at 400°C, which are more than one order of magnitude higher than for dried a sample at the same temperature. In contrast, the total conductivity of pre-hydrated and dried samples is similar at higher temperature, e. g. T > 800 °C. The higher activation energy (e. g. 0.7 eV) for pre-hydrated sample compared to typical value (0.4-0.5 eV) of proton conduction may suggest that the protons are trapped in the material.
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| 9. |
- Andgart, Niklas, et al.
(författare)
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PSD-constrained PAR reduction for DMT/OFDM
- 2004
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Ingår i: Eurasip Journal on Applied Signal Processing. - 1110-8657. ; 2004:10
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Tidskriftsartikel (refereegranskat)abstract
- Common to all DMT/OFDM systems is a large peak-to-average ratio (PAR), which can lead to low power efficiency and nonlinear distortion. Tone reservation uses unused or reserved tones to design a peak-canceling signal to lower the PAR of a transmit block. In DMT ADSL systems, the power allocated to these tones may be limited due to crosstalk issues with many users in one twisted pair bundle. This PSD limitation not only limits PAR reduction ability, but also makes the optimization problem more challenging to solve. Extending the recently proposed active set tone reservation method, we develop an efficient algorithm with performance close to the optimal solution.
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| 10. |
- Andreasson, Jakob, 1975, et al.
(författare)
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Franck-Condon higher order lattice excitations in the LaFe(1-x)Cr(x)O3 (x=0, 0.1, 0.5, 0.9, 1.0) perovskites due to Fe-Cr charge transfer effects
- 2007
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Ingår i: Physical Review B. ; 75, s. 104302-
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Tidskriftsartikel (refereegranskat)abstract
- First and higher order lattice excitiations in the B-site disordered perovskites LaFe(1-x)Cr(x)O3 (x = 0, 0.1, 0.5, 0.9, 1) and La(0.835)Sr(0.165)Fe(0.5)Cr(0.5)O(3-d) are investigated using temperature dependent and polarised inelastic light scattering [lambda = 515 nm (2.41 eV) and 676 nm (1.83 eV)] on oriented crystallites.A peak at approximately 2.4 eV in the imaginary part of the dielectric function of LaFe(0.5)Cr(0.5)O3 is assigned to a charge transfer from Fe 3+ (d5) to Cr 3+ (d3) ions and coupled the appearance of an intense Ag-like mode at approximately 700 cm-1 in the Raman data. This excitation is identified as a symmetric oxygen breathing mode activated by the Fe-Cr charge transfer through an orbital coupling mechanism. Higher order scattering (up to 7th order) of the intrinsic Raman active symmetric breathing mode is also explained by an orbital mediated, electron-phonon coupling, similar to the Franck-Condon effect observed in the Jahn-Teller active perovskite structured manganite LaMnO3. These results show that the Franck-Condon mechanism is a more common mechanism for resonant higher order scattering in solids than previously believed and propose the LaFe(1-x)Cr(x)O(3) system as a model system for electron-phonon coupling and higher order Raman scattering in solids.
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