Papers by Author: Ai Min Li

Abstract: In this study, LiZn ferrites with different content of CNTs (1%-9%) were successfully prepared by a sol-gel method. X-ray diffraction pattern exhibit a relatively high crystallinity of the Li_0.25Zn_0.5Fe_2.25O₄/CNTs composite, and the CNTs still exist after acid treatment and subsequent heat treatment. Then the composite was characterized by scanning electron microscope (SEM) and transmission electron microscope (TEM), the results demonstrate that the particles are nearly spherical in shape and agglomerated to some extent. By a sol-gel method and subsequent calcination, the temperature of LiZn ferrites/CNTs temperature control biomaterials gradually increase and maintain at a certain temperature in the alternating magnetic field, so it can be a potential material used for hyperthermia applications.

Abstract: Tumor of bladder is one of the most common tumors of the urinary system, the vast majority of which come from the epithelial tissue, and of which more than 90% are transitional cell tumors. Tumor of bladder ranks fourth in men and tenth in women. Intravesical instillation of Bacillus Calmette-Guerin (BCG) is recognized as the best way to prevent the recurrence of bladder cancer. But BCG would be excreted with the urine after staying about one hour in the bladder, which has a serious impact on its efficacy. In addition, repeated infusions bring great pains to the patients. This research intends to design a new sustained-release BCG integrated composite materials based on homogenized freeze-dried BCG. The release experiments in vitro of the composite materials show that the release property is good and release time of BCG is more than 48 hours.

Abstract: Carbon nanotubes/zirconia/hydroxyapatite biocomposites was prepared by hot-pressing sintering under Ar atmosphere. The influence of sintering temperature on the mechanical properties and microstructure of carbon nanotube/zirconia/hydroxyapatite biocomposites was studied. We tested the bending strength and fracture toughness by universal electronic materials testing machine. The component of the composites was tested by XRD. The fracture surface of the composites was observed by SEM. The results indicate that the bending strength and fracture toughness of the composites is lower when the sintering temperature is lower than 1200°C. The difference of bending strength and fracture toughness at 1200°C and 1300°C is little. The number of them has risen markedly than the low temperature which reached to189.2MPa and 1.8MPa·m^-1/2 respectively. The composition of the composites is mainly of hydroxyapatite, zirconia, carbon nanotubes, and a small amount of calcium phosphate, which indicated that part of the hydroxyapatite has decomposed. SEM photographs show that the fracture surface of the composites sintered at 1200 °C and 1300 °C is ductile fracture status and has bigger density.

Abstract: Purpose: To assess determination of Bacillus Calmette-Guerin(BCG) concentration integrated in delivery materials for intravesical infusion therapy of superficial bladder cancer. Material and Methods: The standard BCG solution was prepared and divided into two groups. One group was measured by spectrophotometer direct, the other group was determined by using enzyme mark instrument after the solution had cultured. The preliminary experiment study on BCG integrated delivery materials was finished by XTT method. Results: The wavelength of the characteristic peak changes with the variety of the concentration measured by spectrophotometer direct. The concentration of BCG which was embeded in integrated delivery materials for intravesical infusion therapy of superficial bladder cancer was linear with absorbance at 450nm by XTT method in the selected range. Conclusions: It is an incorrect way to measure BCG concentration like determining other solutions by the spectrophotometer immediately and direct. It is the simple, rapid and reliable method by XTT method to study on the performance of the BCG concentration integrated in delivery materials for Intravesical infusion therapy of superficial bladder cancer.

Abstract: Sialon matrix composites were prepared from a reaction mixture of Si₃N₄, Al₂O₃ and Y₂O₃ powders and reinforced with Fe₃Al obtained by mechanical alloying, which also can assist sintering at a low temperature. The specimens were sintered by two–step hot pressing and then characterized for phase composition, microstructure and mechanical properties. The effect of the Fe₃Al variables on the mechanical properties was studied.

Abstract: Oxide membranes are one kind of porous materials with many nano-sized pores. In our work, the two-step anodization method was used to fabricate Anodic aluminum oxide (AAO) membranes. The surface, cross-section micrographs and chemical composition were analyzed by field emission scanning electron microscopy (FESEM). From the FESEM micrographs, it can be easily seen that the self-ordered hexagonal pore channels were parallel and perpendicular to the surface of membrane when AAO membrane was prepared in oxalic acid at 0.2mol/L for 4h. In addition, the biggest pore diameter was 78nm, and the thickness ranged from a few microns to tens of microns in the suitable preparation parameters.