[en] Objective: To evaluate influence of prone/ supine position, gender, operation, bladder distension on bowel irradiated for patients with rectal cancer during pelvic radiotherapy. Methods: 36 patients with rectal cancer were investigated. Treatment plans were created with three dimensional treatment planning system. The dose and volume of bowel irradiated were analyzed according to dose-volume histograms (DVH) for every patient. The prescribed dose was 50 Gy. Results: The extent of bladder distension significantly influenced the mean doses and the V₄₅ high dose volumes of bowel irradiated. The treatment position and gender significantly influenced the V₁₅ low dose volume of bowel irradiated, the operation significantly influenced the mean doses of bowel. Either prone and supine position, or preoperative and postoperative, the doses of bowel irradiated for good bladder distension were lower and the volumes were smaller than that for bad bladder distension. The V₄₅ high dose volume of bowel irradiated for bad and good bladder distension at prone position were 15.3% and 7.4% (P=0.023), respectively, and at postoperative 14.1% and 7.2% (P=0.014), respectively. Conclusions: The doses and volumes of pelvic bowel irradiated were significantly influenced by the extent of bladder distension, and partly influenced by the prone/supine position, gender and operation. (authors)

[en] Spinel transition metal oxide is a promising pseudocapacitive materials but the instability gives it narrow practical application. It is shown herein, that an effective remedy for these problems can be achieved by introducing highly conductive two dimensional (2D) reduced graphene oxide (rGO) substrate on which NiFe₂O₄ nanoparticles are well distributed. The rGO-NiFe₂O₄ hybrids with different NiFe₂O₄ contents were tailored to explore the source of the improvement in capacitance performance. It is found that rGO nanosheets in the hybrid can be used as a conductive substrate to accelerate the electron transport. Moreover, NiFe₂O₄ nanoparticles with a certain volume can simultaneously prevent the restacking of rGO and increase the pseudocapacitance. The G-N3 (30 wt% NiFe₂O₄) hybrid holds enhanced specific capacitance up to 210.9 F g⁻¹ at 0.5 A g⁻¹ far above that of pristine NiFe₂O₄ (50 F g⁻¹), and exhibits superior cycle stability with no obvious capacity loss even after 5000 cycles. This research indicates that a tailoring method can promote the electrochemical performance of NiFe₂O₄, and hopefully accelerate the commercialization of spinel transition metal oxides as electrode materials for supercapacitor.

[en] Spinel transition metal oxides are regarded as one of the finest pseudocapacitive materials, while unexpected stability hinders their practical application. For addressing such issue, herein, we use a simple hydrothermal method to grow NiFe₂O₄ nanoparticles on the surface of reduced graphene oxide (rGO). The rGO nanosheets in the hybrid can be used as a conductive substrate to accelerate the movement of electrons and ions, and they can also inhibit the aggregation of NiFe₂O₄. As the electrochemically active materials, the NiFe₂O₄ nanoparticles can reduce the self-stacking of rGO as well as increase the pseudocapacitance. The rGO-NiFe₂O₄ hybrid delivers improved specific capacitance of 215.7 F g⁻¹ at 0.5 A g⁻¹, and exhibits superior cycle stability with no obvious capacity loss after 10000 cycles. Our work demonstrates a method for effectively improving the electrochemical performance of NiFe₂O₄, and accelerating the commercialization of transition metal oxides as electrode materials for supercapacitors. (paper)