Thermal neutron radiative capture on cadmium as a counting technique at the INES beam line at ISIS: A preliminary investigation of detector cross-talk.

Experimental tests are presented that assess the cross-talk level among three scintillation detectors used as neutron counters exploiting the thermal neutron radiative capture on Cd. The measurements were done at the INES diffractometer operating at the ISIS spallation neutron source (Rutherford Appleton Laboratory, UK). These tests follow a preliminary set of measurements performed on the same instrument to study the effectiveness of this thermal neutron counting strategy in neutron diffraction measurements, typically performed on INES using squashed 3He filled gas tubes. The experimental data were collected in two different geometrical configurations of the detectors and compared to results of Monte Carlo simulations, performed using the MCNP code.

Negative thermal expansion in hybrid improper ferroelectric Ruddlesden-Popper perovskites by symmetry trapping.

We present new results on the microscopic nature of the ferroelectricity mechanisms in Ca3 Mn2O7 and Ca3Ti2O7. To the first approximation, we confirm the hybrid improper ferroelectric mechanism recently proposed by Benedek and Fennie for these Ruddlesden-Popper compounds. However, in Ca3Mn2O7 we find that there is a complex competition between lattice modes of different symmetry which leads to a phase coexistence over a large temperature range and the "symmetry trapping" of a soft mode. This trapping of the soft mode leads to a large uniaxial negative thermal expansion (NTE) reaching a maximum between 250 and 350 K (3.6×10^(-6) K^{-1}) representing the only sizable NTE reported for these and related perovskite materials to date. Our results suggest a systematic strategy for designing and searching for ceramics with large NTE coefficients.

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.

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.

[Etiopathogenesis of endometriosis related infertility]. / Meccanismi eziopatogenetici dell'infertilità nell'endometriosi.

In the last years the entire scientific community has devoted remarkable resources to the understanding of endometriosis. In spite of this, endometriosis remains one of the most complex gynecological diseases, in nearly all of its physiopathological aspects and implications. In particular, the association between endometriosis and infertility has proven to be complex and it has been widely discussed. It is generally accepted that moderate/severe endometriosis related sterility is due to mechanical factors, namely to the distortion/subversion of the regular pelvic anatomy. On the contrary, the factors behind infertility/subfertility related to minimal/mild endometriosis are less clear. None of the hypothesized mechanisms exhaustively explained the infertility related to endometriosis, while it is possible that such disease is caused by multiple factors altogether. The aim of this thorough review of the international literature is to analyze the main etiological factors (i.e. alterations in oocyte maturation and/or growth, defects of fertilization, impairments of implantation or aberrant immunological mechanisms) that are potentially involved, as well as the role that each of the above mentioned factors has in determining the endometriosis related infertility/subinfertility.