Search

Hydroxyapatite [Ca(PO)(OH); or HAp] particles with controlled stoichiometry were precipitated from solution by forced hydrolysis of mixtures of calcium and phosphate salts at a high pH and temperature. The mixing procedure determines the final stoichiometry of the precipitated HAp. The resulting panicles were characterized by FTIR, XRD, TEM, and light scattering and their chemical composition was determined by ICP, indicating that pure crystalline HAp with a narrow size distribution was indeed formed, despite some aggregation being detected by light scattering. The Ca/P ratio was found to depend on the specific preparation route. [ABSTRACT FROM AUTHOR]

The eradication of smallpox was achieved by surveillance and containment vaccination after the failure of mass immunization campaigns. The reasons for this failure are considered in this paper. Comparison of population densities in the Indian subcontinent and Africa show that in highly populated areas even an 80% vaccine coverage will still leave a density of susceptibles high enough to maintain the disease, a finding with important implications for other vaccine campaigns. [ABSTRACT FROM PUBLISHER]

Polypeptide antibiotics, trichopolyns A and B, were isolated from the culture broth of Trichoderma polysporum (Link ex Pers) Rifai (TMI 60146). Assessment of biological activity of the antibiotics against microorganisms was made. [ABSTRACT FROM AUTHOR]