A study by neutron diffraction of crystals of solid benzene at — 55 and — 135 °C has extended the earlier picture of the molecular structure provided by Cox’s X-ray work at — 3 °C. Neutron reflexions in four crystal zones have been examined, leading to values of the atomic co-ordinates and thermal parameters. Superimposed upon the random motion of the carbon and hydrogen atoms, there is an oscillatory angular motion of the molecule in its own plane for which the root-mean-square amplitudes are 7.9°, 4.9° and 2.5°, respectively, at the three different temperatures. At the same time there are small changes in the orientation of the molecules as the temperature is reduced, of such a kind that they pack together more easily along the Z axis, thus accounting for the enhanced thermal expansion along Z compared with X .

In children with insulin-dependent diabetes mellitus (IDDM), deterioration in metabolic control frequently occurs during early adolescence. To prevent this predictable increase in blood glucose levels, we randomly assigned young adolescents with IDDM to an intervention based on problem solving with self-monitoring of blood glucose (SMBG) integrated into standard outpatient care or to standard care only for an 18-mo period. At follow-up, 50% of the standard-care adolescents exhibited greater than 1% increase in glycosylated hemoglobin (HbA1) levels over baseline values, indicating a deterioration in metabolic control, compared to only 23% of the intervention group. Follow-up HbA1 means +/- SD were 10.10 +/- 2.00% for intervention and 11.04 +/- 2.28% for standard-care adolescents, indicating a significantly lower value in the intervention group (P = .04). At follow-up, a greater percentage of intervention than standard-care adolescents reported using SMBG information when they exercised (60.0 vs. 33.3%, chi 2 = 4.29, P = .04). Our data suggest that clinic-based problem-solving groups can be more effective with young adolescents with IDDM than conventional treatment in preventing the expected deterioration in blood glucose.

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