ABSTRACT
In order to construct a novel multifunctional targeting nano-carrier based on pH-redox characteristics of tumor microenvironment,ketone bonds and disulfide bonds were bonded to the oligomeric hyaluronic acid (oHA) being sensitive to pH and the reduction environment.The chemical structure of oligomeric hyaluronic acid-8-mercaptomenthone 1,2-glycerolketal (oHMST) was characterized by 1H NMR,IR and ESI-MS.Curcuminloaded micelles were prepared by dialysis.The single factor investigation was carried out on the dosage form.Some properties,including particle size zeta potential,the morphology of micelles,and pH-sensitivity were studied.The materials were synthesized successfully.The micelles were spheric with a diameter of about 100 nm.The Zeta potential of the micelles was-(21.97 ± 1.08) mV.The in vitro test showed that oHMST carriers have good pH-sensitivity and redox-sensitivity.
ABSTRACT
The experiment was performed at the Laboratory of Ultrasonic Medicine,Department of Biomedical Engineering,Tianjin Medical University between October 2007 and July 2008.Finite difference time domain method which was proposed by Morita to simulate nonlinear ultrasound transmission was applied together with bio-heat-transfers-equation to simulate temperature distribution in the focal region.The results show that when there was a blood vessel in tissue,the blood vessel temperature rise was lower than the surrounding tissue temperature rise.The highest temperature in the surrounding tissue and the focal region above 60 ℃ were decreased with increasing vessel diameter.The blood vessel diameters lead to great changes of temperature distribution.We should consider the influence of blood vessel diameters during high intensity focused ultrasound therapy to destroy tumors
ABSTRACT
AIM:To design a signal collecting system of urethral internal pressure based on embedded microprocessor(ARM).METHODS:Based on ARM,the signal collecting module of urethral internal pressure and signal amplifier circuit were designed with sensor technology.The A/D transition circuit was improved by signal feedback theory to increase measurement accuracy.The software of sensor temperature drift was rectified by second linear interpolation so to enhance the accuracy of data collection.RESULTS:In simulated static urethral internal pressure collection,the signals of urethral internal pressure that sensor collected were corresponded with the location completely and send them into RAM of ARM for following analysis.CONCLUSION:The ARM-based signal collecting system of urethral internal pressure has simple circuit,reliability,lower power consumption,high precision and strong spot data analysis.