J W Pieterse

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The stability of some growth promoting agents in cattle urine, under various temperature storing conditions, was investigated. Bovine urine samples obtained from previous excretion studies which contained zeranol, nandrolone and trenbolone respectively, were stored frozen, at room temperature and in direct sunlight. On days 0, 2, 4, 7 and 10, zeranol and(More)
The authors reply Dr Brooks raises a very important point concerning the transmission of clinical information about patients who are passing from the care of one doctor (unit, hospital) to another. In this example the patient is passing from A&E to an inpatient unit. There is concern that the doctor in the ward may not realise how ill the patient is because(More)
We have constructed a laser system for performing pump-probe experiments with independently tunable pump and probe pulses. The cross correlation between the two pulses, which determines the resolution of the system, is measured to be 150 fs. This system uses two regeneratively mode-locked Ti:sapphire lasers with slightly different repetition rates and(More)
Zeolite supported iron catalysts were prepared by different methods and their catalytic performance was studied in the N2O decomposition reaction. Iron-zeolite was prepared in accordance with the best-known recipes described in literature, not only at ECN, but also at other independent institutes to ensure that the best available expertise in the field was(More)
In order to determine the choice of materials used by dental technicians, questionnaires were sent to 400 registered South African dental laboratories. The response rate was 30.5 per cent. The most frequently used brands were identified. The relationship between usage of materials and demographic variables is discussed.
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