RESUMO
An approach for tailoring the magnetic properties by ion irradiation of granular perpendicular CoCrPt:SiO(2) films grown on silica particles with sizes down to 10 nm was investigated. The as-prepared samples reveal an intriguing scaling dependence of the coercive field and remnant magnetization: both parameters are found to decrease with decreasing particle size. However, Co(+) irradiation at a low fluence of 0.5 x 10(14) cm(-2) already results in an opposite scaling behavior. It is assumed that this modification is due to the enhancement of the intergranular magnetic exchange coupling of the granular CoCrPt:SiO(2) film initiated by Co(+) irradiation resulting in a modified reversal behavior. Further increase of the irradiation fluence beyond 1.6 x 10(14) ions cm(-2) leads to a degradation of the magnetic layer properties, lowering the remnant magnetization and the coercive field in the easy-axis direction. Moreover, the local magnetic properties of the samples were analyzed by magnetic force microscopy revealing magnetic multi-domain cap structures.
RESUMO
Three pigs of 34 kg live weight were fitted with a re-entrant cannula in the duodenum, and with two catheters placed in the jugular vein and carotid artery. They were fed 1.2 kg/d of wheat-dried-skimmed milk diet. Digesta from the proximal duodenal cannula were collected for 12 h on 2 consecutive days; 50% were reintroduced into the respective distal cannula and 50% were stored at -20 degrees C. Three days later 14C-leucine was infused into the jugular vein for 12 h, starting with the morning meal. During this period the digesta from the proximal cannula were collected and stored for analysis while the digesta collected previously were reintroduced into the distal cannula. Blood samples were taken from the carotid artery. The total flow of duodenal digesta in 12 h was 5760 +/- 530 g. On average 70 percent of the radioactivity in digesta was associated with the TCA-precipitable fraction. During hours 0-3 and 11-12 of infusion 60-70% and 96-98% of the radioactivity in the TCA precipitable fractions was in leucine. In the TCA soluble fraction only 30-40 per cent of the radioactivity was associated with leucine. At the plateau 2.1 and 3.3% of infused 14C-leucine and of radioactivity were recovered in the duodenal digesta. The calculated amount of endogenous protein passing the duodenum was 20.4 g/d/pig. The results are discussed in relation to previous studies on protein synthesis and secretion in which 14C- and 15N-amino acids were used.
