Neutron diffraction study of the size-induced tetragonal to monoclinic phase transition in zirconia nanocrystals.

Accurate neutron powder diffraction experiments at several temperatures allow one to monitor the reconstructive tetragonal to monoclinic phase transition as a function of the size of zirconia nanoparticles. The structure of the tetragonal phase observed in the nanocrystals is identical to that observed in micrometric zirconia above 1400 K. A uniaxial strain depending on grain size is observed. The phase transition occurs above a threshold crystal size. These results are analyzed within the Landau theory and can be understood as a mechanism of size-dependent phase transition where the primary order parameter is altered by the nanoparticle size.

Single-crystal study of the m = 2 tubular cobalt oxide, Bi(4)Sr(12)Co(8)O(30-delta).

The structure of the m = 2 tubular compound Bi(4)Sr(12)Co(8)O(30-delta), bismuth strontium cobalt oxide, was determined by single-crystal X-ray diffraction. This phase of orthorhombic symmetry exhibits a very strong tetragonal pseudosymmetry. The structure consists of 90 degrees -oriented Bi(2)Sr(2)CoO(6+delta) slices, four Co atoms wide, forming [Sr(4)Co(4)O(13)](infinity) pillars at their intersection. The Co atoms in these pillars form four corner-sharing CoO(5) bipyramids. In the resulting [Co(4)O(13)] cluster, an anionic disorder is evidenced and discussed. Then, an accurate description of the particular structure of the pillars is given. Finally, a comparison with the Mn tubular compound Bi(3.6)Sr(12.4)Mn(8)O(30-delta) is carried out.

Estimation of direct cost and resource allocation in intensive care: correlation with Omega system.

OBJECTIVE: An instrument able to estimate the direct costs of stays in Intensive Care Units (ICUs) simply would be very useful for resource allocation inside a hospital, through a global budget system. The aim of this study was to propose such a tool. DESIGN: Since 1991, a region-wide common data base has collected standard data of intensive care such as the Omega Score, Simplified Acute Physiologic Score, length of stay, length of ventilation, main diagnosis and procedures. The Omega Score, developed in France in 1986 and proved to be related to the workload, was recorded on each patient of the study. SETTING: Eighteen ICUs of Assistance Publique-Hôpitaux de Paris (AP-HP) and suburbs. PATIENTS: 1) Hundred twenty-one randomly selected ICU patients; 2) 12,000 consecutive ICU stays collected in the common data base in 1993. MEASUREMENTS: 1) On the sample of 121 patients, medical expenditure and nursing time associated with interventions were measured through a prospective study. The correlation between Omega points and direct costs was calculated, and regression equations were applied to the 12,000 stays of the data base, leading to estimated costs. 2) From the analytic accounting of AP-HP, the mean direct cost per stay and per unit was calculated, and compared with the mean associated Omega score from the data base. In both methods a comparison of actual and estimated costs was made. RESULTS: The Omega Score is strongly correlated to total direct costs, medical direct costs and nursing requirements. This correlation is observed both in the random sample of 121 stays and on the data base' stays. The discrepancy of estimated costs through Omega Score and actual costs may result from drugs, blood product underestimation and therapeutic procedures not involved in the Omega Score. CONCLUSIONS: The Omega system appears to be a simple and relevant indicator with which to estimate the direct costs of each stay, and then to organise nursing requirements and resource allocation.

[The economic evaluation of prostatic hyperthermia]. / L'évaluation économique de l'hyperthermie prostatique.

UNLABELLED: The aim of this study is to assess the hospital cost of treating Benign Prostatic Hyperplasia (BPH) by hyperthermia. The cost analysis was conducted simultaneously with a randomized clinical essay comparing hyperthermia to sham; the analysis was promoted by the Committee for Evaluation and Diffusion of Innovative Technologies (CEDIT) of the AP-HP. Cost components are: medical and paramedical staff salaries, supplies, overhead and capital costs. RESULTS: cost per session varies from FF 1200 to FF 5300; cost per treatment varies from FF 2500 to FF 9700 depending upon the equipment used. For comparison, annual drug treatment of BPH varies from FF 2600 to FF 2900. CONCLUSION: important variation in the treatment cost of BPH by hyperthermia is observed depending on the equipment used. Clinical data do not demonstrate improved efficacy with the costlier hyperthermia treatments. Drug treatment seems to be more cost effective than hyperthermia for BPH treatment.

[Pruritus and tardive cutaneous porphyria]. / Prurit et porphyrie cutanée tardive.

Pruritus was present in one half of our cases and ran parallel to the disease, thereby suggesting a causal relationship between it and PCT. Moreover, no correlations could be established between pruritus and the patients' sex, associated treatments (oestrogens, etc.) or underlying disease (liver damage, diabetes mellitus, cancer, hypersideraemia), nor between pruritus and the form of PCT (sporadic or familial) and the levels of urinary porphyrins. Pruritus localized to sun-exposed skin areas belongs to the category of phototoxic symptoms, although a burning sensation is more often observed in such cases, but this cannot explain the generalized pruritus. Immunoglobulin and complement deposits in the vessel walls have been demonstrated in PCT. In addition, the serum of PCT patients may, when irradiated, activate the classical complement pathway, thus promoting the release of mediators. Pro-inflammatory enzymes probably play a secondary role.

Characterization of antibodies reacting with husband's lymphocytes in sera from patients with trophoblastic malignancies.

Lymphocytotoxic antibodies reacting with husband's lymphocytes were demonstrated in 24 sera from women with trophoblastic neoplasia studied before any chemotherapy. These antibodies exhibited a maximal cytotoxic activity at +4 degrees C. They reacted mainly with B lymphocytes as assessed by microlymphocytotoxicity assays using B- or T-cell enriched subpopulations and T- or B-cell lines as targets. They could not be absorbed out with platelets or erythrocytes, and did not react with autologous lymphocytes. In one double-labelling immunofluorescence experiment, these antibodies could be stained by rhodamine-conjugated Fab'2 anti-mu fragments and thus appeared to belong to the IgM class. They were shown to react mainly with surface Ig (SIg) bearing lymphocytes, plus a minor SIg negative subset. Studies with panels of allogeneic normal B cells and of HLA homozygous B-cell lines showed that the target antigen(s) recognized by these antibodies is clearly distinct from HLA-D antigens. Corresponding antigens seem to be expressed on placenta, since the lymphocytotoxic antibodies could be absorbed out with trophoblastic homogenates and one serum reacted with JAR cells (cultured choriocarcinoma line). An enhancing role of such antibodies in the growth of trophoblastic malignancies may be suggested.