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Coherently strained BiFeO3 epitaxial films deposited on (001)-oriented (LaAlO3)0.3(Sr2AlTaO6)0.7 have a tetragonal crystal form, a stress-distorted version of the rhombohedral phase. A conversion from coherent BiFeO3 to a new, tilted pseudotetragonal phase with the c/a ratio exceeding 1.2 is observed beyond the critical thickness of 60 nm. X-ray reciprocal space maps display that this highly elongated metastable structure is monoclinically distorted by ~0.2° and exhibits an out-of-plane tilt of ~3°. These observations are at odds with traditional understandings that a coherent epilayer should turn into its parent structure upon increasing the thickness, providing a new insight into the strain relaxation mechanism of epitaxial films. We show that in the heating and cooling cycles, the transition between these two phases is completely reversible and is associated with the alleviation of thermal stress. Our results reveal that the coherent BiFeO3 epilayer with tetragonal symmetry stabilized by moderate compressive strain behaves as a structural bridge that links the thermally stable rhombohedral phase and the metastable tetragonal-like phase with a giant axial ratio. Moreover, the finding of a BiFeO3 phase mixture in our study extends the threshold in-plane strain of the stress-driven morphotropic phase boundary to a value as low as -2.3%. [ABSTRACT FROM AUTHOR]

As the largest freshwater lake located in the most controversial transboundary river in Asia, the Tonle Sap Lake is one of the most productive ecosystems in the world. However, uncertainty remains because of the inability to measure nonlinear inundation dynamics in remote lakes at fine spatial and temporal resolutions, let along the water levels. This research attempted to explore the reliability of radar altimetry data to detect the inland water level of inundation areas, like that of Tonle Sap Lake over the past decade. The results indicated that the Jason-2 and Jason-3 radar altimetry data were able to retrieve water level with high accuracy (R² = 0.9232 and confidence coefficient of 98%), and the composite index was proven to be the optimal method to identify inundation area of the Tonle Sap Lake compared to the single-band threshold method and modified normalized difference water index by applying Moderate Resolution Imaging Spectroradiometer Surface Reflectance products MOD09A1. The fluctuation trend of inundation area and water level were basically consistent with the precipitation, presenting a distinct lagging relationship. More important was the truth that the downstream water level had poor correlation with the upstream runoff both in flood period and non-flood periods (R² = 0.0542 and 0.2873, p < 0.01), which indicated that the upstream explorations over Lancang-Mekong River had little effects on the downstream water volume. [ABSTRACT FROM AUTHOR]

The degree of forest vegetation restoration and reconstruction and the impact of different afforestation tree species on plant diversity in Mount Tai, China were evaluated. We selected 6 kinds of 50-year-old plantations along Tianwai village, Hongmen, Tianzhu peak and Taohuayuan lines. The results show that: 1) Robinia pseudoacacia plantation has significantly lower tree layer richness, Shannon-Wiener diversity and Simpson diversity than other plantations; Pinus tabulaeformis and larch tree plantations have significantly lower shrub layer Shannon -Wiener and Simpson diversity than other plantations, Pinus tabulaeformis and Pinus densiflora have significantly lower Pielou evenness than the other four plantations; Pinus tabulaeformis plantation and Platycladus orientalis plantation have significantly lower herb layer richness than the other four plantations, while Pinus tabulaeformis plantation has significantly lower Shannon-Wiener diversity and Simpson diversity than the other five plantations. 2) Species richness, Shannon-Wiener diversity and Simpson diversity of tree and shrub layers are all presented from highest to lowest in the following order: Mount Meng > Mount Tai > Mount Yi, while Mount Tai plantation has the highest herb layer species richness, Shannon-Wiener diversity and Simpson diversity. These results provide basis for the regulation and prediction of regional forest vegetation restoration and reconstruction in the future. [ABSTRACT FROM AUTHOR]

In the paper, a novel metal surface nitriding method is presented by using an atmospheric pressure non-thermal transferred arc plasma technique. In the N2/H2 plasma nitriding process, the surface of stainless-steel is treated by the arc root, which shows an irregular movement in a circle-like zone with about 5 mm diameter observed by high speed camera. The discharge has characteristics of high voltage and low current, and the gas temperature of the arc column plasma is only about 2900 K determined by the diatomic molecule N2+(B2Σu+→X2Σg+) fitting method. It is found that the NH radical production in plasma plays an important role in the nitriding process. The thickness of nitrided layer can reach 60 μm after processing of 120 min under the optimal experimental conditions. The surface hardness of stainless-steel increased from 220 to about 1200 HV0.1 (Vickers hardness under the force of 0.1 kg) after plasma treatment. The treating saturation time for stainless-steel surface hardness reaching to 1200 HV0.1 is around 9 min. [ABSTRACT FROM AUTHOR]

The predictors for the prognosis of gastric cancer (GC) are not clear. We intended to explore the role of PTEN and microsatellite (MS) in GC, showing their potential as prognostic markers. Primary gastric cancer tissues, adjacent normal tissues, and clinicopathological parameters of 187 patients were collected. The expression level of PTEN and MS status were classified by immunohistochemistry (IHC). The relationship among indicators was compared by the chi-square test. The survival curves were delineated by Kaplan-Meier and tested by Log-rank methods. The impact of multiple factors on prognosis was determined by COX proportional hazards model. Significantly, PTEN expression was associated with lymphatic invasion (p=0.011) and Lauren grade (p=0.015). MS status was associated with differentiation (p=0.006) and Lauren grades (p=0.035). TNM stage was associated with MS status under positive PTEN expression (p=0.014). Patients with microsatellite stability (MSS) had worse median overall survival (OS) than that with microsatellite instability (MSI) (p=0.013). Patients with negative PTEN expression had a worse median OS than that with positive PTEN expression (p<0.001). The tumor subtype of PTEN negative-MSS (p<0.001) and PTEN negative-MSI (p=0.042) were strong predictors of poor survival. Negative PTEN expression and MSS might lead to unfavorable prognosis due to their association with clinicopathological parameters of GC. PTEN expression and MS status could be predictors for the prognosis of GC. [ABSTRACT FROM AUTHOR]