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Objective: To explore the association between the Type and approach of hysterectomy and oncological survival of women with stage II cancer of the endometrium. Patients and methods: 684 women with stage II endometrial cancer were included. Eligible cases were grouped by type of hysterectomy (simple hysterectomy or radical hysterectomy)and approach of hysterectomy (laparoscopy or laparotomy). The baseline characteristics were compared among groups. The survival outcomes (disease-free survival and overall survival) were calculated and compared among groups, and the underlying confounding factors were adjusted by the Cox proportional hazard regression analysis. Results: The radical hysterectomy group and the simple hysterectomy group had 217 cases and 467 cases, respectively. Between the groups, the difference in 5-year disease-free survival (87.3% versus 87.9%, HR=0.97, P=0.87) and 5-year overall survival (83.8% versus 83.8%, HR=0.95, P=0.95) was not statistically significant. The laparotomy group and the laparoscopy group had 277 cases and 407 cases, respectively. Between the groups, the difference in 5-year disease-free survival (88.7% versus 87.1%, HR=1.22, P=0.34) and 5-year overall survival (85.5% versus 82.7%, HR=1.00, P=0.99) was not statistically significant. Conclusion: For long-term oncological survival, radical hysterectomy is not superior to total hysterectomy in stage II endometrial cancer. Also, for stage II cancer of the endometrium, laparoscopic hysterectomy is as oncologically safe as open hysterectomy.
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Carbides/carbon composites are emerging as a new kind of binary dielectric systems with good microwave absorption performance. Herein, we obtain a series of tungsten carbide/carbon composites through a simple solvent-free strategy, where the solid mixture of dicyandiamide (DCA) and ammonium metatungstate (AM) is employed as the precursor. Ultrafine cubic WC1-x nanoparticles (3-4 nm) are in situ generated and uniformly dispersed on carbon nanosheets. This configuration overcomes some disadvantages of conventional carbides/carbon composites and is greatly helpful for electromagnetic dissipation. It is found that the weight ratio of DCA to AM can regulate chemical composition of these composites, while less impact on the average size of WC1-x nanoparticles. With the increase in carbon nanosheets, the relative complex permittivity and dielectric loss ability are constantly enhanced through conductive loss and polarization relaxation. The different dielectric properties endow these composites with distinguishable attenuation ability and impedance matching. When DCA/AM weight ratio is 6.0, the optimized composite can produce good microwave absorption performance, whose strongest reflection loss intensity reaches up to - 55.6 dB at 17.5 GHz and qualified absorption bandwidth covers 3.6-18.0 GHz by manipulating the thickness from 1.0 to 5.0 mm. Such a performance is superior to many conventional carbides/carbon composites.
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The morphology-dependent property of crystal materials has aroused extensive attention and raised high requirements for subtly tailoring the morphology of micro-/nanocrystals. Herein, we develop an in situ etching method for preparation of Prussian blue (PB) microcrystals with morphology evolution by progressively increasing the concentration of chloroplatinic acid in the reaction system. These PB microcrystals with controllable morphologies are employed as photo-Fenton reagents to degrade organic pollutants. PB hexapods (PB-hpds) and PB hexapod stars present superior catalytic performance to pristine PB microcubes and other PB intermediates with truncated corners or edges because of their high specific surface areas and adequate exposure of FeIII-NC coordination active sites. In the reusability test, the reused PB-hpds present more efficient catalytic performance for rhodamine B decomposition compared with the pristine catalyst. According to more investigations, the reasonable mechanism is proposed that FeIII-NC exhibits higher catalytic activity than FeII-CN in the specific coordination environment. The increased content of surface FeIII-NC coordination active sites is the key factor in accelerating the decomposition of H2O2 and enhancing the photo-Fenton performance of PB-hpds. Several operating parameters including catalyst dosage, H2O2 concentration, pH value, and reaction temperature are evaluated in detail. Classical quenching experiments and electron paramagnetic resonance measurements further reveal that HO⢠should be responsible for high performance of catalysts. This work will be significant for tailoring the morphology of the materials and arousing more attention to enhance the stability and reusability of catalysts.
RESUMEN
Traditional magnetic metal and alloy materials suffer from easy oxidation and high density, which hinders their practical application as high-performance microwave absorbers. Lightweight and durability have become new goals in the fabrication of the next generation of microwave absorbers. Herein, we report the synthesis of polypyrrole (PPy) nanosphere/reduced graphene oxide (rGO) composites through chemical reduction of self-assembly PPy nanosphere/GO hybrids. PPy nanospheres and GO are integrated effectively by πâ»π interaction of dual conjugated systems. When the mass ratio of PPy nanospheres to rGO is 0.6:1, the resultant composite, PPy/rGO-0.6, presents comparable/superior reflection loss characteristics to those magnetic metals and their related graphene-based composites in previous studies. Electromagnetic analysis reveals that well-matched characteristic impedance, multiple polarization loss, and good conductivity loss are, together, responsible for the excellent microwave absorption performance of PPy/rGO-0.6. More importantly, PPy/rGO-0.6 also exhibits good microwave absorption after being treated at 423 K for a long time. This work provides a new idea for designing and preparing a high-performance microwave absorber with lightweight and durable features.