RESUMO
We present a laboratory electromagnet capable of generating magnetic fields up to ±0.48 T, specifically designed as a perpendicular flux source for thin film samples in an ambient environment. The magnet features a 250 mm diameter clear access bore above the sample plane, thus offering compatibility with a wide variety of experimental apparatus. Despite its generous size, the magnet thermally dissipates less than 1 kW at maximum field. A shaped ferromagnetic core is used to amplify and homogenize the field B, leading to an estimated uniformity of ±1.5 mT (â²0.3%) in B within a 28 mm2 zone at maximum field. The sample stage is thermally regulated and isolated from the magnet, enabling temperature control with ±5 mK precision even at elevated magnetic fields.
RESUMO
A procedure is described for producing a high quality C. pyogenes vaccine. A satisfactory antibody response was obtained by administering 3 subcutaneous injections of vaccine at 10-day intervals, using doses of 2,0 ml for rabbits, 5,0 ml for sheep and 10,0 ml for cattle. The titres resulting from this procedure compared favourably with those obtained from following the more intensive schedule and higher doses of vaccine recommended by the British Veterinary Codex. The antibody response was at its best 1-2 months after immunization but dropped to a plateau 6 months after immunization. Mice were also successfully immunized against challenge with 1,5x108 organisms by the application of 3 doses of vaccine administered at 10-day intervals.
