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To better understand the behavior of M50NiL steel under carburizing and nitriding duplex treatment, different carburizing temperatures (ranging from 890 to 980 °C) were used for the carburizing pretreatment. The surface microstructures were characterized by X-ray diffraction (XRD), laser scanning confocal microscopy, microhardness testing, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results indicate that the proportions of γ′ and large submicron precipitates increase with increasing carburizing temperature, which corresponds to an increase in large primary carbides. The increase in the number/size of large primary carbides promotes the diffusion of nitrogen. The resulting changes in the nanometric precipitates after nitriding lead to different levels of solid solution by nitrogen (reaching a maximum at a 920 °C carburizing pretreatment). The growth mechanism of the submicron precipitates is proposed. The effect of various precipitates and the diffusion behavior of C and solid solution of N on the hardening behavior are discussed.

Nup88 is overexpressed in a number of types of carcinomas and is associated with myometrial invasion, but its exact expression pattern in endometrial cancer and premalignant lesions is unknown.To evaluate the role of Nup88 in endometrial cancers and atypical endometrial hyperplasia and its clinicopathological significance.Nup88 expression was examined by immunohistochemistry in samples from 104 endometrial cancers, 21 atypical endometrial hyperplasia lesions, and 40 normal endometria. All samples were from patients who underwent surgery at the First Hospital of Hebei Medical University (Shijiazhuang, China) between April 2006 and December 2009. Nup88 expression was compared between the groups and associations were assessed between Nup88 and clinicopathological characteristics of the subjects.Nup88 expression in cancer (76% of samples) and atypical hyperplasia (91%) was significantly higher compared to normal endometrium (33%, both P0.001), but there was no significant difference between endometrial cancer and atypical hyperplasia (P=0.237). The expression of Nup88 increased significantly with increasing exposure time to estrogen (P=0.033).Nup88 may be related to the occurrence of endometrial cancers and premalignant lesions. Nup88 might be a useful biomarker for pre-malignant lesions and early-stage endometrial cancer.

This article reports the effect of pre-existing carbides prepared by different heat treatments on the nitriding behaviour during a carburizing and nitriding duplex treatment of an M50NiL steel. The goal was to achieve an improved understanding of the relationship between the pre-existing carbides and nitriding behaviour. The M50NiL steel was carburized at 950 °C, heat treated at different quenching temperatures (ranging from 1000 to 1150 °C) and tempering temperatures (ranging from 500 to 580 °C), and finally nitrided at 500 °C. The surface layers were characterized by means of X-ray diffraction (XRD), laser scanning confocal microscopy (LSCM), scanning electron microscopy (SEM), Vickers microhardness measurement and transmission electron microscopy (TEM). The results show that the formation of intergranular precipitates was greatly related to the presence of pre-existing carbides, which led to a change in the carbon content in the matrix and showed different dissolving capacities. The compound layers consisted of γ′ (Fe4N) and e (Fe2-3N) phases as well as a minor amount of Fe3O4. The pre-existing carbides had no effect on the composition of the compound layer. For the diffusion of nitrogen, a density of pre-existing carbides that was too high or too low was unfavorable, as it greatly decreased the thickness of the nitrided layer. At the quenching temperature of 1100 °C and the tempering temperature of 540 °C, the thickest nitrided layer herein and a good hardness distribution were obtained, which was attributed to the optimum density of pre-existing carbides. This study provides information regarding how to obtain a thick nitrided layer by controlling pre-existing carbides during the duplex treatment of M50NiL steels.