463 research outputs found
The S(0) structure in highly compressed hydrogen and the orientational transition
A calculation of the rotational S(0) frequencies in high pressure solid
para-hydrogen is performed. Convergence of the perturbative series at high
density is demonstrated by the calculation of second and third order terms. The
results of the theory are compared with the available experimental data to
derive the density behaviour of structural parameters. In particular, a strong
increase of the value of the lattice constant ratio and of the
internuclear distance is determined. Also a decrease of the anisotropic
intermolecular potential is observed which is attributed to charge transfer
effects. The structural parameters determined at the phase transition may be
used to calculate quantum properties of the rotationally ordered phase.Comment: accepted Europhysics Letter
Optimised pulse duration for the laser cleaning of oil gilding
The laser cleaning problem of gold leaf gilded surfaces was investigated here. Preliminary irradiation tests carried out on pure gold leaf standards evidenced the crucial importance of the laser pulse duration for avoiding serious
damages. Optimised pulse duration providing good cleaning results with negligible side effects was then selected and successfully used in the restoration of three
Renaissance masterpieces
Preliminary results of the Italian neutron experimental station INES at ISIS: Archaeometric applications
The INES project was sponsored by the CNR Neutron Spectroscopy Advisory Committee, stressing the importance of realizing an Italian Neutron Experimental Station (INES) at the world most powerful pulsed neutron source (ISIS,
Rutherford Appleton Laboratory, UK) and evidencing the strategic value that such a test station would assume in the field of applied sciences like, for example, chemistry,
material science, Earth science, crystallography, and last, but not least, in the field of science applied to the study of cultural-heritage artifacts
Preliminary results of the Italian neutron experimental station INES at ISIS: Archaeometric applications
The INES project was sponsored by the CNR Neutron Spectroscopy Advisory Committee, stressing the importance of realizing an Italian Neutron Experimental Station (INES) at the world most powerful pulsed neutron source (ISIS,
Rutherford Appleton Laboratory, UK) and evidencing the strategic value that such a test station would assume in the field of applied sciences like, for example, chemistry,
material science, Earth science, crystallography, and last, but not least, in the field of science applied to the study of cultural-heritage artifacts
An innovative approach for migraine prevention in young age: a preliminary study
Headache is one of the commonest conditions to affect children and adolescents in industrialized countries. Effective pharmacological treatments without side effects are still lacking. Ginkgolide B, an herbal constituent extract from ginkgo biloba tree leaves, is a natural antiplatelet activating factor (PAF). PAF is a potent proinflammatory and nociceptive agent released during the inflammation process. Therefore, Ginkgolide B can be considered a promising non-pharmacological tool for treatment of migraine with and without aura. We propose to determine the efficacy of Ginkgolide B as preventive treatment in a group of young patients suffering from migraine without aura. A small sample of 24 young patients suffering from migraine without aura entered the open-label prospective trial. Migraine without aura was diagnosed according to International Headache Society criteria. The treatment was well tolerated and the compliance was good. These preliminary data show that Ginkgolide B seems to be effective as preventive treatment in reducing migraine attack frequency and in attenuating the use of symptomatic medication in our small series of children with primary headache
Neutron Tomography at INES: First experimental results
A neutron tomography apparatus has been designed and installed at the Italian neutron experimental station (INES) at ISIS (UK). The instrument has a double aim: an additional opportunity for the INES users and a “bench test” for an instrument component that will be proposed for installation on some of the new neutron scattering instruments of Target Station 2 (TS2) of ISIS. Here, we present the first experimental results achieved with this apparatus
Compositional and microstructural characterization of Celtic silver coins from northern Italy using neutron diffraction analysis
Abstract The silver coinage of Celtic tribes settled in northern Italy (IV–I century B.C.) is a topic characterized by several issues, such as chronology, attributions and relationships between emissions produced in different periods. In order to provide numismatists with new data, several specimens, belonging to different typologies, have been analysed with neutron diffraction technique to overcome surface alteration and to provide bulky compositional and structural information of the coins. Measurements performed with the INES diffractometer at the ISIS facility provided essential data for numismatics research. A clear silver debasement occurring between the first and latter emissions has been traced, due to inflation processes which can be related with the increasing power of Roman Republic in the Cisalpine region. Moreover, compositional data enabled for the first time to identify internal evolutions inside typologies defined by numismatists. The silver loss has also been used to establish a relative chronology between different emissions. Other parameters such as texture index, residual strains and grain dimensions have been useful to understand technical aspects of minting procedures during Iron Age
Joint negative muon data analysis and Monte Carlo simulation methods for the characterization of thin layers
Musoni c atom X-ray Emission Spectroscopy (μXES) is a novel tech- nique in the broad field of non-destructive methods for cultural heritage analysis. It relies on the interaction of a probe of negative muons with matter and following emission of X-ray radiation. Since the muon mass is about 207 times bigger than the electron, these emitted X-rays are highly energetic and are characteristic of the emitting atom, making it possible to cover a wide part of the periodic table (from lithium to uranium). The multi-elemental range, a negligible self-absorption of the X-rays and very low residual activity left in the sample after irradiation make μXES a very powerful probe for material characterization. In addition, by coupling the data analysis with Monte Carlo simulation methods, it is possible to asses the depth of the layers that are present in a given sample. In this work, preliminary results of the analysis on two gilded surfaces are reported
A moderate 500-m treadmill walk for estimating peak oxygen uptake in men with NYHA class I-II heart failure and reduced left ventricular ejection fraction
Background: Maximal cardiopulmonary exercise testing (CPX) is the gold-standard for cardiorespiratory fitness assessment in chronic heart failure (CHF) patients. However, high costs, required medical supervision, and safety concerns make maximal exercise testing impractical for evaluating mobility-impaired adults. Thus, several submaximal walking protocols have been developed and currently used to estimate peak oxygen consumption (VO(2)peak)in CHF patients. However, these tests have to be performed at close to maximum exercise intensity. The aim of this study was to examine the validity of a 500-m treadmill-walking test carried out at moderate intensity for estimating VO(2)peak in community-dwelling adult and elderly patients with CHF and reduced left ventricular ejection fraction (HFrEF).Methods: Forty-three clinically stable men with HFrEF (age 67.7 +/- 9.2 years, and left ventricular ejection fraction, LVEF 38% +/- 6%) underwent exercise testing during an outpatient cardiac rehabilitation/secondary prevention program. Each patients completed a CPX, and a moderate and self-paced (11-13/20 on the Borg scale) 500-m treadmill-walking test. Age, weight, height, walk time, and heart rate during the 500-m test were entered into prediction equations previously validated for VO(2)peak estimation from a 1000-m walking test in patients with cardiovascular disease and preserved LVEF.Results: Directly measured and estimated VO(2)peak values were not different (21.6 +/- 4.9 vs 21.7 +/- 4.6 mL/kg/min). The comparison between measured and estimated VO(2)peak values yielded a correlation of R = 0.97 (SEE = 0.7 mL/kg/min, P < 0.0001). The slope and the intercept coincided with the line of identity (Passing and Bablock analysis, P = 0.50). Residuals were normally distributed, and the examination of the Bland-Altman analysis do not show systematic or proportional error.Conclusions: A moderate and self-regulated 500-m treadmill-walking test is a valid tool for VO(2)peak estimation in patients with HFrEF. These findings may have practical implications in the context of transitioning from clinically based programs to fitness facilities or self-guided exercise programs in adults and elderly men with HFrEF
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