Abstract: The present invention relates to an improved immunoassay which increases the sensitivity of detection of substance specific immunoglobulin from a sample. A method of the invention relates to the provision of a plurality of forms of a substance, at least one of which forms includes the natural extract of that substance. The other forms present may be recombinant or natural antigenic components of the substance.

Abstract: The present invention relates to an improved immunoassay which increases the sensitivity of detection of substance specific immunoglobulin from a sample. A method of the invention relates to the provision of a plurality of forms of a substance, at least one of which forms includes the natural extract of that substance. The other forms present may be recombinant or natural antigenic components of the substance.

Abstract: Fertilizers with a slow and controlled release of nitrogen are obtained by condensing urea with formaldehyde in three condensation stages carried out under well-determined conditions of pH, temperature and formaldehyde/urea molar ratio and up to well-determined viscosities of the resulting product. The first stage is carried out in the presence of methanol, the second stage after addition of formic acid and the third stage after neutralization and addition of a further amount of urea. The condensation stages are followed by a terminal heat-treatment at 200.degree.-400.degree. C for 0.5 to 5 minutes.