RESUMO
This paper presents an experimental study about the preparation, by electrospinning, of uranium carbide fibers with nanometric grain size. Viscous solutions of cellulose acetate and uranyl salts (acetate, acetylacetonate, and formate) on acetic acid and 2,4-pentanedione, adjusted to three different polymer concentrations, 10, 12.5, and 15 weight %, were used for electrospinning. Good quality precursor fibers were obtained from solutions with a 15% cellulose acetate concentration, the best ones being produced from the uranyl acetate solution. As-spun precursor fibers were then decomposed by slow heating until 823 K under argon, resulting in a mixture of nano-grained UO2 and C fibers. A last carboreduction was then carried out under vacuum at 2073 K for 2 h. The final material displayed UC2-y as the major phase, with grain sizes in the 4 nm-10 nm range. UO2+x was still present in moderate concentrations (~30 vol.%). This is due to uncomplete carboreduction that can be explained by the fiber morphology, limiting the effective contact between C and UO2 grains.
RESUMO
Os autores apresentam o programa seguido (período de 1962 a 1986) no tratamento de 469 casos de carcinoma de tireóide, operados no Hospital do Servidor Público Estadual e Hospital Santa Catarina. O exame anatomopatológico foi feito pelo método da congelaçäo, durante o ato cirúrgico, e posteriormente em parafina. O controle da radicalidade cirúrgica foi clínico e através de mapeamento com I. todo o tecido tireoidiano remanescente iodocaptante, quando presente, foi deixado (captaçäo < 5%) e retirado (> 5%) cirurgicamente ou a custa de uma dose de I; também metástases iodocaptantes foram "queimadas" com I. No seguimento, os autores realçam a importância da manutençäo do estudo eutireoidiano (administraçäo de T4), bem como controle clínico e monitorizaçäo com marcadores específicos (tireoglobulina e calcitonina)
