We investigate the impact of turbulent suppression of parallel heat conduction on the cooling of post-flare coronal loops. Depending on the value of the mean free path l T associated with the turbulent scattering process, we identify four main cooling scenarios. The overall temperature evolution, from an initial temperature in excess of 10 7 K, is modeled in each case, highlighting the evolution of the dominant cooling mechanism throughout the cooling process. Comparison with observed cooling times allows the value of l T to be constrained, and interestingly this range corresponds to situations where collision-dominated conduction plays a very limited role, or even no role at all, in the cooling of post-flare coronal loops.

The absorption of oral methotrexate in syrup form has been compared in six patients with that of an identical IV dose (50 mg/m2). There was variable absorption amongst the group with respect to maximum levels achieved and the time taken to reach those levels. The area under the time-concentration curve was always smaller when the drug was given orally than after IV administration. A total of 33 patients receiving methotrexate for a variety of tumour types were followed for response to treatment and toxicity. A significantly longer methotrexate half-life (t1/2) was found in nine partial responders (9.2 +/- 1.6 h) than in the nonresponders (3.8 +/- 0.7 h). Severe methotrexate toxicity was not seen though occasional mucositis, conjunctivitis, and diarrhoea occurred in seven patients. The side effects could not be predicted from the dose, the bioavailability data, or the serum creatinine. Measurements of serum and urine methotrexate levels are useful in the assessment of absorption and bioavailability of the drug the prediction of tumour response.