Bulk laser-induced damage threshold of titanium-doped sapphire crystals.

The bulk laser-induced damage threshold (LIDT) fluence of Ti:sapphire is determined under single-pulse irradiation from the femtosecond to nanosecond temporal regimes in the visible and near-infrared spectral domains. In the range of explored laser conditions, the LIDT fluence increases with both pulse duration and wavelength. The results are also compared to laser interaction with sapphire samples and show an increased resistance to laser damage when the material is doped with Ti(3+) ions. These conclusions are of interest for robust operation of high-peak-power femtosecond Ti:sapphire laser chains.

[Cardiac toxicity of ajmaline. Comparison of acute voluntary poisoning with complications of the ajmaline test]. / Toxicité cardiaque de l'ajmaline. Comparaison des intoxications aiguës volontaires et des accidents du test à l'ajmaline.

A comparative and retrospective study of 59 cases of acute voluntary self-poisoning observed at the Toxicology Department of Fernand Widal Hospital, and 15 cases of complications of the Ajmaline test observed in the Cardiology Department of Bichat Hospital showed a similarity in the cardiac effects of high dosage regardless of the mode of administration of the antiarrhythmic. Acute suicidal poisoning in adults or accidental poisoning in children caused toxic effects at doses over more than Ig: they are characterised by their sudden onset after a latent period of 1 to 2 hours and their short duration (no effects after the 12th hour). The ECG changes included:--First degree atrioventricular block (15 p. 100).--Intraventricular conduction defects were observed in almost all cases. They were proportional to the dose taken and were of prognostic interes (no cardiac arrests when the QRS remained less then 0,2 sec).--ST-T wave changes were observed in all patients. They lasted longer and were of no prognostic importance.--Extrasystoles and ventricular tachycardia are nearly always associated with poor hemodynamic tolerance (70 p. 100 of cardiac arrests, compared to only 16 p. 100 in this absence). This intoxication is serious with a mortality of 24 p. 100 of the reported cases and of 9 p. 100 of cases admitted to an Intensive Care Unit.--The complications of the Ajmaline test were similar, the time of apparition being a few minutes instead of a few hours. There were no deaths or serious hemodynamic complications in this series. This is without doubt related to the observation of the contraindications and the fractional administration of the Ajmaline. We conclude that oral Ajmaline, though well tolerated at therapeutic does may cause severe toxic overdose effects. Although its use remains justified in the treatment of arrhythmias, it should not be used for the symptomatic treatment of palpitations and neurovegetative imbalance.

[Acute poisoning by Gyromitra esculenta (author's transl)]. / L'intoxication par Gyromitra esculenta.

This kind of poisoning is scarce in France, on the contrary it is most frequent in Eastern Europe. Clinical picture associating cytolytic hepatitis, seizures, and hemolysis reminds us intoxication by hydrazine. In fact there is some evidence that the toxin of this mushroom--called gyromitrin--is transformed in the stomach in methylhydrazine. The mechanism of hepatotoxicity of the later can be compared with that of the metabolites of isoniazid.