Raman spectra of ammonia borane: low frequency lattice modes.

We have measured the Raman spectrum of ammonia borane at low temperature (T = 15 K) and across the orthorhombic-to-tetragonal phase transition at T = 225 K. A comprehensive study of the low frequency lattice modes using Raman spectroscopy has been carried out. Data analysis has been complemented by a density functional theory calculation of which the results have been used for a detailed assignment of the Raman active modes. The analysis of the spectroscopic measurements taken across the phase transition seems to be consistent with the increasing orientational disorder of the molecular components and seems to be compatible with the equalization of the a and b lattice constants characteristic of the tetragonal phase.

Raman and inelastic neutron scattering study on a melt-infiltrated composite of NaAlH4 and nanoporous carbon.

Inelastic neutron scattering and Raman scattering spectra of a melt-infiltrated composite of NaAlH(4) and active carbon fibers have been measured at low temperature for two sample conditions: as prepared and subjected to hydrogen desorption-absorption cycling. After a careful data analysis, the present experimental results have been compared to the corresponding spectroscopic data taken from bulk NaAlH(4) and Na(3)AlH(6). Evident signatures induced by infiltration process onto the NaAlH(4) phonon bands have been detected, showing up as a strong peak broadening and smoothing together with, in some cases, an energy shift. Traces of Na(3)AlH(6), appearing as an extra intensity between 130 and 200 meV, seem also confirmed. A substantial agreement between neutron and Raman measurements has been found for the as-prepared melt-infiltrated sample, while for the cycled sample the two techniques produced rather dissimilar results. However, this apparent discrepancy can be explained by considering the different penetration depths of the two spectroscopic probes. Further work, both experimental and based on ab initio simulations, is surely needed in order to rationalize the finding of the present measurements.

Ancient and historic steel in Japan, India and Europe, a non-invasive comparative study using thermal neutron diffraction.

The production and refinement of steel has followed very different paths in different parts of the Eurasian continent. In aiming to characterize the similarities and differences between various smelting and smithing methods, we have analysed steel samples from four different areas and historic periods: the Koto Age in Japan (twelfth-sixteenth century), the Moghul Empire in India (seventeenth-nineteenth century), the Ottoman Turkish Empire (seventeenth century) and the late Middle Ages (fifteenth century) in Italy. The best quality steel was employed for forging arms and armour of high quality, so that we have selected samples from Japan, India, the Middle East and Italy belonging to such a category. Traditional methods, such as metallography, used to characterize different steels in terms of their carbon contents, microconstituents and slag inclusions, entailed an invasive approach. Since many of the selected artefacts are in a very good state of conservation, a different and non-invasive approach was desirable. To this aim, we have used time of flight neutron diffraction on the Italian Neutron Experimental Station diffractometer, located at the pulsed neutron source ISIS in the United Kingdom. By this technique, we were able to quantify the phase distribution of the metal phases, the slag inclusion content, and the oxidation state of the samples, both as average concentration on the whole artefact and in selected gauge volumes. The results of the present investigation offer an interesting picture of the steel metallurgy in different areas of the world.

Temperature behavior of the AlH3 polymorph by in situ investigation using high resolution Raman scattering.

A Raman investigation of the AlH(3) polymorph has been carried out at a low temperature (20 K) under helium atmosphere (2 bar). The pristine material was composed of three polymorphs, namely, the α, ß, and γ phases. The ß phase has been removed by warming the sample to 70 °C, while further heating at 100 °C was used to remove the γ phase. This allowed us to evidence, on a purely experimental basis, the characteristic Raman spectrum for each phase. Raman spectra, for the three phases, have been also calculated using density functional theory, and the results have been compared to the present experimental data, allowing for a univocal assignment, to each phase, of its characteristic spectral features.

Characterization of copper alloys of archaeometallurgical interest using neutron diffraction: a systematic calibration study.

Neutron diffraction experiments have been performed on laboratory-prepared samples of copper alloys to determine their microscopic phase characteristics. The aim of this experiment is to set up a database that can be used in future neutron diffraction measurements on metal samples mainly of archaeological interest.

NIMROD: The Near and InterMediate Range Order Diffractometer of the ISIS second target station.

NIMROD is the Near and InterMediate Range Order Diffractometer of the ISIS second target station. Its design is optimized for structural studies of disordered materials and liquids on a continuous length scale that extends from the atomic, upward of 30 nm, while maintaining subatomic distance resolution. This capability is achieved by matching a low and wider angle array of high efficiency neutron scintillation detectors to the broad band-pass radiation delivered by a hybrid liquid water and liquid hydrogen neutron moderator assembly. The capabilities of the instrument bridge the gap between conventional small angle neutron scattering and wide angle diffraction through the use of a common calibration procedure for the entire length scale. This allows the instrument to obtain information on nanoscale systems and processes that are quantitatively linked to the local atomic and molecular order of the materials under investigation.

High resolution Raman and neutron investigation of Mg(BH4)2 in an extensive temperature range.

Raman spectra of Mg(BH(4))(2) have been measured in an extensive temperature range, from 15 to 473 K. Taking into account the high temperature conversion from the alpha to the beta phase, we have observed evident signatures of this phase transition and determined the Raman vibrational spectrum of each phase. The neutron scattering spectra of the beta phase sample were also recorded. The present experimental results have been compared to the density functional theory calculations available in the literature, and a substantial agreement has been found.

A neutron imaging device for sample alignment in a pulsed neutron scattering instrument.

A neutron-imaging device for alignment purposes has been tested on the INES beamline at ISIS, the pulsed neutron source of Rutherford Appleton Laboratory (U.K.). Its use, in conjunction with a set of movable jaws, turns out extremely useful for scattering application to complex samples where a precise and well-defined determination of the scattering volume is needed.

Neutron diffraction characterization of Japanese artworks of Tokugawa age.

Neutron time-of-flight diffraction technique has been used to characterize some Japanese historical artifacts. With this method, metal samples can be analyzed in their bulk properties without need of sampling. Results shown here were obtained at the Italian Neutron Experimental Station (INES@ISIS) located at the pulsed neutron source ISIS (UK). The parallel use of a scanning electron microscope equipped with an energy-dispersive X-ray fluorescence device (SEM-EDX) permitted a full quantitative characterization of the investigated samples, namely four hand-guards (Tsubas) of Japanese swords attributed to the Tokugawa age. In particular, we were able to obtain, in a totally non-invasive non-destructive way, a full quantitative phase characterization of the samples, a detailed Bragg peak broadening analysis, and a quantitative texture determination. These results, complemented with those obtained via the traditional analysis method of SEM-EDX, allowed a full characterization of both the bulk and the surface of the artifacts.

Symptoms accompanying fibromyalgia.

OBJECTIVE: The objective of the study was to investigate the relationship between spontaneous and provoked pain in fibromyalgia and to evaluate the frequency of disturbances associated with muscle pain, including some disturbances which are not usually considered as typical symptoms associated with pain in fibromyalgia. METHODS: In sixty-seven patients with fibromyalgia the severity of spontaneous pain was assessed by a visual analogue scale and the severity of provoked pain by an original method, which includes the evaluation of the number of tender points and the evaluation of the intensity of provoked pain. The method used to assess the severity of provoked pain is more sensitive than other methods currently used. The occurrence of accompanying symptoms was also evaluated. The investigation included the occurrence of paresthesias of the upper limbs, hemorrhoids and epistaxis, which are not usually considered as typical symptoms associated with fibromyalgia. RESULTS: No significant correlation was observed between the severity of spontaneous and provoked pain. The following disturbances were more frequent in the examined patients than in general population: headache, chronic fatigue, sleep disorders, irritable bowel syndrome, restless legs syndrome, paresthesias in the upper limbs, hemorrhoids and epistaxis. CONCLUSIONS: Spontaneous and provoked pain should be considered two independent clinical features of fibromyalgia. Paresthesias in the upper limbs, hemorrhoids and epistaxis should be considered as typical symptoms associated with fibromyalgia. Hemorrhoids and epistaxis are frequently due to a diathesis characterized by laxity of connective tissues and fibromyalgia could be a consequence of such a diathesis.

An apparatus for simultaneous thermodynamic and optical measurements, with large temperature excursions.

We report the design and realization of an integrated system for measuring, at the same time, the thermodynamic and spectroscopic features of nanoporous materials interesting for hydrogen storage purposes. The whole investigation cycle, from thermal activation to the actual investigation of uptake and release of hydrogen, is carried out in the same vacuum tight vessel, equipped with an optical window, whose temperature can range between 10 and 750 K, up to a maximum pressure of 50 bars. The system has been designed to investigate properties of carbon nanotubes but its use can be extended to any kind of nanoporous sample such as, for example, carbon nanofibers, zeolytes, metal organic frameworks, and similar materials.

Low power radiofrequency electromagnetic radiation for the treatment of pain due to osteoarthritis of the knee.

OBJECTIVE: To investigate the analgesic effect of low power radiofrequency electromagnetic radiation (RF) in osteoarthritis (OA) of the knee. METHODS: In a randomized study on 40 patients the analgesic effect of RF was compared with the effect of transcutaneous electrical nerve stimulation (TENS). RF and TENS applications were repeated every day for a period of 5 days. The therapeutic effect was evaluated by a visual analogue scale (VAS) and by Lequesne's index: tests were performed before, immediately after and 30 days after therapy. RESULTS: RF therapy induced a statistically significant and long lasting decrease of VAS and of Lequesne's index; TENS induced a decrease of VAS and of Lequesne's index which was not statistically significant. CONCLUSIONS: A therapeutic effect of RF was therefore demonstrated on pain and disability due to knee OA. This effect was better than the effect of TENS, which is a largely used analgesic technique. Such a difference of the therapeutic effect may be due to the fact that TENS acts only on superficial tissues and nerve terminals, while RF acts increasing superficial and deep tissue temperature.

Intracardiac Doppler assessment of left valve inflow in first-trimester fetuses with increased nuchal translucency: preliminary observations in trisomy 21.

OBJECTIVES: To perform a qualitative assessment of the pulsed Doppler waveform profile at the level of left atrioventricular valve inflow in first-trimester fetuses with increased nuchal translucency thickness (NT), in order to compare those with trisomy 21 and those with normal karyotype. METHODS: This was a review of 285 consecutive fetuses with increased NT. Pulsed Doppler velocity waveforms of left atrioventricular valve inflow were recorded. The E-wave, A-wave and velocity profile in the aorta were displayed. Cases were classified into two patterns: Pattern A included those in which the E-wave velocity crossed the A-wave before the baseline in all waveforms; Pattern B included those in which the lowest E-wave velocity crossed the baseline but not the A-wave in at least one of the profiles. The karyotype was determined and the frequency of occurrence of Patterns A or B in fetuses with normal karyotype and those with trisomy 21 were compared. RESULTS: Of the 285 cases, 230 were assigned to Pattern A and 55 to Pattern B. There were 47 cases of trisomy 21, 22 had other chromosomal abnormalities, and 212 had a normal karyotype; in four cases the karyotype was unknown. Among the 212 karyotypically normal fetuses, five had heart defects, five had other structural defects, three suffered spontaneous intrauterine death and one was terminated. Pattern A was found in 200/212 (94.3%) cases with normal karyotype, in 12/47 (25.5%) cases with trisomy 21, and in 17/22 (77.3%) cases with other chromosomal abnormalities. Pattern B was found in 12/212 (5.7%) cases with normal karyotype, in 35/47 (74.5%) cases with trisomy 21 (chi-square test, P < 0.001), and in 5/22 (22.7%) cases with other chromosomal abnormalities. CONCLUSIONS: Intracardiac Doppler qualitative assessment of left valve inflow in first-trimester fetuses with increased NT shows differences between normal and trisomy 21 fetuses, probably reflecting differences in myocardial function.

Density of phonon states in solid parahydrogen from inelastic neutron scattering.

We have measured the inelastic neutron scattering spectrum of solid parahydrogen (at low pressure and T=13.3 K) using the thermal original spectrometer with cylindrical analyzers spectrometer at the ISIS pulsed neutron source (UK). From the experimental spectrum we have obtained the parahydrogen density of phonon states which has been compared with the estimates available in the literature. The present determination improves substantially the previous experimental scenario from the point of view of both statistics and accuracy. The comparison with the most recent estimate obtained from a quantum mechanical simulation of the molecular dynamics calls for an improvement of the computational methods..