[en] At present, about one third of female cancers are breast cancers. In France there are 25000 new cases per year and it affects about 10% of woman being. Biochemical tests of 11β- [(cyclopentadienyl-tri-carbonyl-rhenio) ethynyl]estra- 1,3,5(10)- triene-3, 17β-diol have proved the viability of its use in that cancer therapy. But that molecule is only effective with radioactive rhenium and our aim consists in focusing on its synthetic route. By working on its free 11β ligand analogue, the first 17α-cyclopentadienyl derivative of 17α-ethynyl-estradiol has been prepared and three potential routes have been focused: the first is based on a trans-metallation reaction with Re(CO)₅Br, the second on ReO₄ reduction with DIBAL-H and the third on a Wenzel DLT reaction extension. Cyclopentadiene synthesis in 17α position opens up new horizons for steroids labelling by organometallic complexes and an example is given by the labelling of 17α-ethynyl-estradiol by titanium (IV) complex. Moreover, two new derivatives of 17α-ethynyl-estradiol labelled in 3 and 17α position by Re(CO)₃(η⁵-C₅H₄) moiety have been prepared and biochemically analyzed. To explore the impact of 11β substitute on steroids behaviour (estrogen and anti-estrogen), 11β- [(cyclopentadienyl-tri-carbonyl-rhenio)ethynyl]extra- 1,3,5(10)- triene-3, 17β-diol has been prepared and biochemically analyzed. This is the first example in rhenium series of estrogenic hormone labelled in 11β position that has been indirectly synthesized in nine steps through an 11 oxo derivative. (author)

[en] Relativistic heavy ion collisions present the opportunity of creating in laboratory small volumes of hot, dense nuclear matter. On the experimental point of view, the collision events are characterized by a great number of fragments, especially in the direction of the projectile. The first part is devoted to a survey of relativistic heavy ion physics. Then, we present two experimental set-ups which permit, in particular, the analyse of light fragment production at small angles. We present experimental results concerning light projectiles on Ca, Nb, Pb targets, with energies from 200 A.MeV up to 600 A.MeV. Different aspects of the collision are put in evidence. Momentum and charge differential cross section are extrapolated to other projectile/target systems; that is used in a transport calculation of Ne ions in a target of biological interest (water), with a collimator. We show that nuclear fragmentation produces a dispersion in the spatial and energy distributions, and that one light fragments have a range greater than the projectile range. That last point causes a distortion of the Bragg curve, and that distortion must be taken into account for the application of heavy ions to radiotherapy problems. 95 figs., 8 tabs

[en] The ongoing increase in the concentration of infrared-absorbing gases in the atmosphere is already causing and will continue to cause a growing unbalance in the radiation budget of the earth, and consequent warming of the lower atmosphere and earth surface. This climate phenomenon is the manifestation of the greenhouse or blanketing effect of absorbing gases (also known as ''greenhouse gases'') in the earth atmosphere. The main chemical species responsible for the build-up of the greenhouse effect are carbon dioxide, methane and chlorofluorocarbons (CFCs) or freons. Despite new regulatory efforts made by governments to slow down the emission of these gases, the combined atmospheric burden could be equivalent to doubling the pre-industrial concentration of carbon dioxide (2xCO₂) by the middle of next century. The global warming of the earth surface would eventually reach about 4 deg. C if the 2xCO₂ concentration then was maintained constant for a long period. As it is, the transient response of climate to an increasing greenhouse effect is delayed by 50 to 100 years. For this reason, we observe now a much smaller climate warming than would occur for climate equilibrium with the present atmospheric composition, i.e. 125% the pre-industrial concentration of CO₂. Impacts of this phenomenon will range from disturbances of the existing hydrological regime of the planet to rise of the global mean sea-level. A warmer atmosphere means more rain but also faster evaporation: consequences in terms of the availability of water resources are unclear at temperate and high latitudes, but an aggravation of aridity in sub-tropical latitudes is probable. Sea-level rise may reach 50 cm by 2100. In general, the rate of climate warming when the climate system starts responding to the greenhouse effect could be 0.3 deg. C per decade, far exceeding the ability of natural ecosystems to adapt effectively to the change. (author). 5 refs, 2 figs

[en] The system for dismantling an installation under a controlled atmosphere is made by a tool polluting the atmosphere, a gas blanket creating a continement zone around the tool, an extractor removing polluted gas from the zone, a purifier for the extracted gas and a controller regulating the flow of gas in the blanket and keeping the installation at constant pressure

[en] At a time when the public perception of climate change is recovering from the controversies and vocal dissent aired during the recent years, we thought it would be interesting to begin this special issue with an interview of Pierre Morel. As the originator of physical climate studies in France, he established and led (until 1975) the Dynamic Meteorology Laboratory of CNRS, a component of the Pierre-Simon Laplace Institute (IPSL), which has become the focus of climate research in France. However his professional activities were pursued largely in an international context. Alumnus of Ecole Normale Superieure in Paris, physicist, first director of scientific research and advanced technology programs in the French space agency CNES from 1962 to 1964 and then Professor at the University of Paris, he specialized in the field of geophysical fluid dynamics. In 1967, he became a member of the international Joint Organizing Committee for the Global Atmospheric Research Programme (GARP) and eventually vice-chairman of the Committee until 1982. He conceived and promoted a number of satellite projects, in particular the operational ARGOS navigation and data collection System on NOAA polar-orbiting meteorological satellites and the European geostationary meteorological satellite Meteosat. In 1982, he became the first director of the international World Climate Research Programme that followed upon GARP and continued in this function until 1994. He then joined NASA Headquarters in the capacity as Senior Visiting Scientist in the Office of Mission to Planet Earth. This unorthodox professional career gave Pierre Morel an exceptionally broad, possibly unmatched, view of all facets of climate science and global observations. Herve Le Treut, with whom this interview was prepared and conducted, is the current director of IPSL, a member of the French Academy of Sciences, and professor at Ecole Polytechnique and University Pierre and Marie Curie of Paris. We are grateful to both for their participation in this demanding scientific information endeavour. (authors)

[en] The nuclear excitation by electron capture (NEET) process may occur when the energy differences between two nuclear levels and between two electronic states are nearly equal, provided the quantum selection rules are fulfilled. These resonant conditions drastically limit the number of possible candidates, even though thermodynamic conditions encountered in hot dense plasmas do modify the orbital electronic binding energy and the resonance conditions. ²⁰¹Hg, with a low-lying isomeric state located at 1.565 keV, can be excited by NEET process in a laser-created plasma. However, its correct calculation requires nonlocal thermodynamic equilibrium (non-LTE) atomic physics treatment because current laser-created plasmas do not reach high-enough temperature in the area at LTE. In this article, we describe the calculation leading to an estimated excitation rate and discuss the influence of LTE/non-LTE physics with an average-atom model and the use of a Gaussian variance calculation to estimate the broadening around the mean energy mismatch.

[en] The rising price of uranium has led uranium producers to increase their plant capacity. The new project proposed to increase capacity is based on processing low-grade uranium by heap leaching. It is necessary to modify the plant, particularly the solvent extraction unit, to handle the increased flow. The goal of our study is to determine the minimal changes necessary to process the whole flow. Several stages have been carried out (i) thermodynamic modelling of the solvent extraction process to determine the capacities of the SX plant and the impact of the modification and (ii) pilot tests at the plant of the different configurations proposed by modelling. This paper presents results of the pilot tests performed at the plant. (authors)

[en] Y₂ O₃-Zr O₂ polycrystals have received special attention as structural and ionic conductor ceramics because of their properties such as mechanical strength, chemical inertness, high melting temperature, and electrical conductivity. To study the effects of dopants on the grain growth kinetics and other physical properties, we have prepared and characterized CSZ and TZP materials doped with Mg O, Ti O₂ and Th O₂. It has been observed that the mobility of the grain boundaries was suppressed by the addition of cations with a valence less than 4+, and unchanged or enhanced with the tetravalent additions depending on the ionic size, as expected from the space charge concept and the impurity drag effect. The implications of the observations on the performance of zirconia based ionic conductors in practical applications such as oxygen sensors and heating elements are discussed. (author)

[en] The cross-section of the ²³⁹Pu (n,2n)²³⁸Pu reaction is relatively well-known between 8 and 12 MeV for incident neutron energy but different models disagree between 6 and 8 MeV as well as beyond 12 MeV. A new measurement method has been developed, this method is based on the recovery of the quantity of Pu²³⁸ produced by the reaction during a few hundreds hours of irradiation and at an energy of 6.88 MeV for the incident neutron. The result confirms the disagreement between the JEFF3.3 evaluation and previous data. One of the issues of this method is to determine the right efficiency of the recovery of the quantity of Pu²³⁸. Another issue was to get a quantity of ²³⁹Pu pure enough as the experiment has shown that some Pu²³⁸ initially present in the Pu²³⁹ target was recovered as reaction product. (A.C.)

[en] The inelastic scattering of free electrons in hot plasma by nuclei is considered, taking into account the screening of the nuclear Coulomb field by surrounding electrons. The Coulomb excitation cross-section of the nucleus is calculated in distorted-wave Born approximation (DWBA). Numerical calculations for "2"0"1Hg show that the electron screening suppresses the nuclear excitation at low electron energies. Temperature dependence of the Coulomb excitation rate of "2"0"1Hg in the equilibrium plasma is analyzed as well. (authors)