Abstract: There is disclosed a process for producing a polyester copolymer. The process comprises the step of condensating a hydroxyacid, a diol, a dicarboxylic acid and a functionalizing agent selected to form a prepolymer having a polyester copolymer backbone with arms comprising cross-linkable groups extending therefrom. The process also comprises the step of coupling said prepolymer in the presence of a coupling agent to cross link the arms of plural prepolymer backbones and thereby form said polyester copolymer comprising said plural straight chain polyester copolymers coupled to each other by said cross-linked arms. The polyester copolymer may be biodegradable and may be used as a modifier to increase the strength of polylactic acid.

Abstract: The present invention relates to radioactive magnetic fluids, process for preparing them and use thereof. Particularly, the present invention relates to the radioactive magnetic fluids for treatment or diagnosis of cancer, process for preparing them and use thereof. The radioactive magnetic fluids of the present invention include the component of Cu2+ which radiates a ?-ray and ?-ray. The ? radiation can effectively kill the tumor cells. Since the ? radiation are easily imaged with ?-camera, the magnetic fluids can be gathered to the treatment site with the radiograph under external magnetic field. Therefore, the radioactive magnetic fluids of the present invention can be used for treatment of cancer with minimal side effects. Also, the tightly bonded decanoic acid and nonanoic acid layer of the present invention not only increase particle-particle repulsion but also take hydrophilicity, to disperse homogeneously and stably the magnetic nanoparticles in water.