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Objective To explore mechanical property changes of methyl vinyl silicone rubber modified by ferric nanoparticles and its dispersed phase.Methods Mechanical properties such as Shore A hardness,tensile strength,elongation at break,tearing rate of permanent deformation and tearing strength of pre-prepared ironic nanoparticle enhanced silicone rubber and carbon-coated ferric particle reinforced silicone rubber were tested according to national standards.A thermal field emission scanning electron microscope (TFE-SEM) was used to investigate the morphology of both surface and fracture of the composite materials and to observe the dispersion of ferric nanoparticles in them.Results Mean values of Shore A hardness,tensile strength,elongation at break,tearing permanent deformation rate and tear strength of modified composites increased with the increasing amounts of ferric nanoparticles,however,when the quota of ironic nanoparticles in the composite formula were greater than 17 phr,carbon-coated ferric nanoparticles more than 19 phr,the mean values of tensile strength of two composites stopped increasing and presented the declining trend.When the quota of ferric nanoparticles in the formula exceeding 15 phr,the mean values of elongation at break and tear strength began to decrease in the formula ratio of silicone rubber/ferric nanoparticles up to 85:15,while the Shore A hardness of samples increased all the way.Ferric nanoparticles dispersed evenly on the surface of composites.Nanopowder aggregation in the fracture surface of both composites could be observed at the formula ratio of 85:15 of silicone rubber/iron nanoparticle and 87:13 of silicone rubber/carbon-coated iron specimen.Conclusion Effect of iron nanapareticles and carbon-coated ferric nanoparticles on the mechanical properties of the reinforced methyl vinyl silicone rubber depends on the nanoparticle size,additive amount and agglomeration.
RESUMEN
Objective To study the value of transurethral electro-resection for renal pelvic tumor.Methods Transurethral electro-resection was performed on 11 patients after resection of the kidney.A F8 catheter was inserted into the bladder via the distal end of the ureter.The mucosal tissues around the ureter were then cut,and the ureter was fixed to the catheter and removed by pulling out the catheter.Results The operation was completed in all of the cases with a mean operation time of 115 min(65 to 170 min).None of the patients developed infection or hemorrhage after the surgery.11 patients were followed up for 6 to 18 months(mean,11 months),and no one died during the period.No tumor implantation or other intra-bladder masses were found.ConclusionsTransurethral electro-resection is feasible and safe for renal pelvic tumor.