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PubMed2001

Orbital frustration at the origin of the magnetic behavior in LiNiO2.

We report on the ESR, magnetization, and magnetic susceptibility measurements performed over a large temperature range, from 1.5 to 750 K, on high-quality stoichiometric LiNiO2. We find that this compound displays two distinct temperature regions where its magnetic behavior is anomalous. With the help of a statistical model based on the Kugel'-Khomskii Hamiltonian, we show that below T(of) approximately 400 K, an orbitally frustrated state characteristic of the triangular lattice is established. This then gives a solution to the long-standing controversial problem of the magnetic behavior in LiNiO2.

Journal Article↗

PubMed2000

[Hypocomplementemic urticarial vasculitis].

BACKGROUND: Low-complement urticarial vasculitis is an uncommon condition associating urticaria, glomerulonephritis, obstructive ventilatory disorders, and anti-Ciq antibodies. CASE REPORT: We report a case in a 34-year-old woman who developed urticaria with purpura, membranoproliferative glomerulonephritis (creatinine 238 mumol/l) and bronchial obstruction with bronchectasia. Total complement and the C3 fraction were low. Anti-C1q antibodies were found in the serum and anti-DNA antibodies were negative. Aggravation of the respiratory and renal failure progressed despite corticosteroid therapy, leading to death at 4 months. DISCUSSION: Bronchial obstruction in low-complement urticarial vasculitis results from emphysema and is often life-threatening. Our case exhibited an unusual feature due to the lack of radiodetectable emphysema, the presence of bronchectasia and the rapid degradation of the respiratory function.

Adult↗

PubMed1997

[Central venous catheters. Prospective surveillance of a hospital].

OBJECTIVES: All the central venous catheters (CVC) inserted at the Saint-Antoine Hospital between December 5, 1994 and June 6, 1995 were prospectively studied in order to better define practices in the management of CVC and to determine the rate of catheter-related infections. METHODS: The following data were recorded for each CVC: insertion procedure, clinical data, catheter dressings, removal, catheter-related infections, bacteriological findings. Catheter-related infections were distinguished from probably catheter-related infections and localized skin infections. RESULTS: Among 325 patients, a total of 414 catheters were inserted. At the end of the surveillance period, 350 (85%) had been removed, 43 (10%) were still in place and 21 (5%) were lost to follow-up. Analysis of procedures such as cutaneous disinfection, routine replacement of the i.v. sets or changes of dressings showed wide variations between care units and within the same unit. The overall incidence of catheter-related infections was 0.24 per 100 days of catheterization. Infections occurred 29 +/- 34 days after insertion. Microorganisms responsible for catheter-related bacteremia were mostly Gram positive (84%) and Gram negative (16%). Sixty-two infections (15%) were clinically suspected by physicians, leading to the catheter removal in 84% of cases. Out of the 43 CVC sent to the laboratory, 29 (67%) were negative (i.e., "sterile") in quantitative culture of the tips as described by Brun-Buisson, suggesting that the CVC was unnecessarily removed. Bacteriological analysis ordered by physicians were not always relevant. For example, 76% of CVC received by the laboratory were systematically sent although they were not suspected of infections. Conversely, only 61% of exsudate formation at the insertion site were collected and analyzed. CONCLUSION: This study was designed to recall good guidelines to the hospital staff. Results will lead to the development of a better use of antiseptics and to the implementation of appropriate and standardized procedures to reduce risk infection.

Adult↗