Résumé
[Objective]To study the degradation of nano-nacre powder and the biocompatibility of the composite artificial bone made from this nano-scale powder in vivo.[Method]The nano-nacre powder made through mechanical grinding and the artificial bones made from this powder and PDLLA(poly-D,L-lactide acid) were implanted into the femoral holes and the femoral muscle sacs of rats respectively.Normal micron-nacre powder and the artificial bones made from this powder and PDLLA were implanted as control group,and blank group was set up without implanting anything.X-ray photography was performed immediately and at 2,4 and 8 weeks after operation.The animals were injected with tetracycline for fluorescent mark before being killed.Then,the gross specimens,histological and SEM(scanning electron microscope) observations were performed.[Result]All the observations showed that nano-nacre powder degraded faster than micron-nacre powder,meanwhile,the bone defect recovery was the fastest in this group.Both of the composite artificial bones made from those two kinds of nacre powder had the good connection with the adjacent tissue.[Conclusion]The degradation of nano-nacre powder is faster than that of micron-nacre powder in vivo,and it can promote the growing of new bone.Nano-nacre composite artificial bone also has good biocompatibility.It is a kind of better bioactive degradable material.
Résumé
Copper and iron, chelated by cupferron and extracted by methyl-iso-butyl-ketone at pH 3.4-4.2, are enriched and the absorption signals of AAS are enhanced by the organic solvent, thus result in a smaller sample requirement (less than 100 mg hair) and a higher sensitivity (almost 20 times the original aqueous solution). The recoveries of zinc, copper and iron for human hair analysis are in the range of 98-106%, and the coefficients of variation are 0.6, 2.5 and 6.5% respectively. The recommended method is simple, easy to manipulate and suitable to medical application.
Résumé
The zinc content in red blood cells has been proved to be a better index than either serum Zn or plasma Zn for nutritional and metabolic studies. A simple direct dilution method followed by AAS determination of Zn has been developed. The optimum dilution ratio is found to be 1 : 19 of deionized water. Recovery of this method is consistantly between 96-97% with a coefficient of variation less than 3%.