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A Pradel

Publications and source records attributed to A Pradel.

5 recordsLinked to original sources
PubMed2006

Pressure-induced site-selective disordering of Ge2Sb2Te5: a new insight into phase-change optical recording.

We demonstrate that , the material of choice in phase-change optical recording (such as DVD-RAM), can be rendered amorphous by the application of hydrostatic pressure. It is argued that this structural change is due to a very strong second-nearest-neighbor Te-Te interaction that determines the long-range order in the metastable cubic phase of and also to the presence of vacancies. This newly discovered phenomenon suggests that pressure is an important factor for the formation of the amorphous phase which opens new insight into the mechanism of phase-change optical recording.

Journal Article↗
PubMed1996

A 119Sn solid-state nuclear magnetic resonance study of crystalline tin sulphides.

Non-spinning and magic angle spinning (MAS) 119Sn nuclear magnetic resonance (NMR) spectra of the binary tin sulphides SnS and SnS2 as well as of a number of stoichiometric compounds from the ternary system Na2S-SnS2 have been recorded. The isotropic chemical shift was found to cover a range of more than 800 ppm and allows us to distinguish between different coordination numbers of Sn(IV) present in tin sulphides. Moreover, the chemical shift anisotropy (c.s.a.) is shown to be a sensitive indicator for deformations in the coordination sphere of the tin atom and can be discussed with respect to the known structures of the compounds.

Isotopes↗
PubMed1996

Creutzfeldt-Jakob disease from contaminated growth hormone extracts in France.

We diagnosed Cruetzfeldt-Jakob disease in 34 patients (16 definite, 18 probable) who had received human growth hormone extract for various period of time (mean +/- SD, 2.9 years), but particularly during the period between January 1984 and July 1985, a potential high-risk factor. Disease duration for deceased patients (n = 30) was 17 +/- 9 months. The clinical picture was homogeneous, starting with cerebellar ataxia and ocular motor disorders in about 90% of the patients. Neurologic deterioration, including dementia and myoclonic jerks, occurred within months. The high number of cases (1.5% of those treated between 1959 and 1988, 3% of those treated during the putative high-risk period) is still unexplained. We discuss the possibility that new cases will be detected,the risk of contaminating the general public, and the sanitary measures undertaken to prevent this.

Adolescent↗
PubMed1994

[Iatrogenic Creutzfeldt-Jakob disease. Lessons from cases secondary to extracted growth hormone in France].

Thirty cases of Creutzfeldt-Jakob disease (CJD) after cadaveric growth hormone treatment have been counted by the National Reference Center for iatrogenic CJD. The clinic presentation is homogeneous, beginning by neurological troubles (diplopia, unsteady gait) evolving rapidly in few months towards a severe neurological deterioration, insanity and death. All patients were treated between January 1984 and July 1985. The risk to transmit CJD with treatments of human origin (pituitary derived treatment, blood, placentas and corneal and dura mater graft) is analyzed. The selection of donors and techniques of purification on the one hand, the rigor of the indication and the quality of the followup on the other hand, are the only guarantees to reduce the risks secondary to utilization of products of human origin.

Adult↗