RESUMEN
Objective To explore the change rules of peak area ratio of STR loci to Amelogenin (AMEL) locus (STR/A M EL ), a sex-determ ining gene in DNA degradation, and to evaluate the application of STR/A MEL value in the estim ation of DNA degradation degree. Methods DNA w as extracted from iliopsoas, and the variations of STR/A MEL value (Penta E/AMEL, Penta D/AMEL, FGA/AMEL) w ere analyzed after the artificial degradation w as m ade by DNaseⅠ, and the changes of these three ratios of the iliopsoas naturally degraded in an outdoor environm ent w ere also analyzed. The regression curves w ere analyzed using the periods of DNA degradation and outside the body as the independent variable (x) and the STR/A MEL value as the dependent variable (y) and three curve equations under tw o conditions w ere established. Results B oth under the conditions of artificial and natural degradation, STR/A MEL value had a negative relationship w ith the degradation tim e. The relationship betw een STR/A MEL and degradation tim e can be w ell sim ulated by the cubic function. R2 w as over 0.99 under controlled degradation condition and over 0.86 under natural degradation condition. Conclusion The STR/A MEL value (Penta E/AMEL, Penta D/AMEL , FGA/AMEL ) is negatively related w ith the DNA degradation degree, w hich follow s m athem atical regression m odels strictly, and it m ight be applied to evaluate the DNA degradation degree.
RESUMEN
With a microsystem or micropump, the release rate of drug delivery is able to be controlled easily to maintain the therapeutic efficacy. A piezoelectric membrane-valve micropump for implantable and carryhome drug delivery system is developed and tested. The influence elements of dynamic performance of the PZT actuator and valve were analyzed, and the calculation method of resonant frequency of the membrane valve was provided. Study results showed that the output performance of the micropump depended on the coupling effect of the actuator and valve. For a given actuator, the output value and the optimal frequency of a micropump could be enhanced only by valve design. Two micropumps with different valve dimensions were fabricated for comparing examination. The smaller -valve micropump obtained higher output values (the maximum flow rate and backpressure being 3.5 ml/min and 27 KPa, respectively) and two optimal frequencies (800 Hz and 3 000 Hz). The larger -valve micropump achieved lower output values (the maximum flow rate and backpressure being 3.0 ml/min and 9 KPa, respectively) and one optimal frequency (about 200 Hz). The test results suggest that the output values and optimal frequency of micropump can be improved by changing the valve dimension, and the viewpoint that checkvalve micropump works only with low acting frequency is wrong.