3 research outputs found
Mapping winter wheat with combinations of temporally aggregated Sentinel-2 and Landsat-8 data in Shandong Province, China
Winter wheat is one of the major cereal crops in China. The spatial distribution of winter wheat planting areas is closely related to food security; however, mapping winter wheat with time-series finer spatial resolution satellite images across large areas is challenging. This paper explores the potential of combining temporally aggregated Landsat-8 OLI and Sentinel-2 MSI data available via the Google Earth Engine (GEE) platform for mapping winter wheat in Shandong Province, China. First, six phenological median composites of Landsat-8 OLI and Sentinel-2 MSI reflectance measures were generated by a temporal aggregation technique according to the winter wheat phenological calendar, which covered seedling, tillering, over-wintering, reviving, jointing-heading and maturing phases, respectively. Then, Random Forest (RF) classifier was used to classify multi-temporal composites but also mono-temporal winter wheat development phases and mono-sensor data. The results showed that winter wheat could be classified with an overall accuracy of 93.4% and F1 measure (the harmonic mean of producer’s and user’s accuracy) of 0.97 with temporally aggregated Landsat-8 and Sentinel-2 data were combined. As our results also revealed, it was always good to classify multi-temporal images compared to mono-temporal imagery (the overall accuracy dropped from 93.4% to as low as 76.4%). It was also good to classify Landsat-8 OLI and Sentinel-2 MSI imagery combined instead of classifying them individually. The analysis showed among the mono-temporal winter wheat development phases that the maturing phase’s and reviving phase’s data were more important than the data for other mono-temporal winter wheat development phases. In sum, this study confirmed the importance of using temporally aggregated Landsat-8 OLI and Sentinel-2 MSI data combined and identified key winter wheat development phases for accurate winter wheat classification. These results can be useful to benefit on freely available optical satellite data (Landsat-8 OLI and Sentinel-2 MSI) and prioritize key winter wheat development phases for accurate mapping winter wheat planting areas across China and elsewhere
Regulation of Prostate Development and Benign Prostatic Hyperplasia by Autocrine Cholinergic Signaling via Maintaining the Epithelial Progenitor Cells in Proliferating Status
SummaryRegulation of prostate epithelial progenitor cells is important in prostate development and prostate diseases. Our previous study demonstrated a function of autocrine cholinergic signaling (ACS) in promoting prostate cancer growth and castration resistance. However, whether or not such ACS also plays a role in prostate development is unknown. Here, we report that ACS promoted the proliferation and inhibited the differentiation of prostate epithelial progenitor cells in organotypic cultures. These results were confirmed by ex vivo lineage tracing assays and in vivo renal capsule recombination assays. Moreover, we found that M3 cholinergic receptor (CHRM3) was upregulated in a large subset of benign prostatic hyperplasia (BPH) tissues compared with normal tissues. Activation of CHRM3 also promoted the proliferation of BPH cells. Together, our findings identify a role of ACS in maintaining prostate epithelial progenitor cells in the proliferating state, and blockade of ACS may have clinical implications for the management of BPH
Robust CO2 and H2 resistant triple-layered (Ag-YSZ)/YSZ/(La0.8Sr0.2MnO3-δ-YSZ) hollow fiber membranes with short-circuit for oxygen permeation
Oxygen selective ceramic membranes have many important applications, not only for air separation but also as membrane reactors for cost-effective chemical synthesis. However, the prerequisite to realize these potentials is their stability in the presence of acid gases of CO2 and reducing atmosphere containing H2 and CH4. This work seeks to validate the applicability of robust triple layer hollow fiber membranes consisting of (Ag+YSZ)/YSZ/La0.8Sr0.2MnO3-δ (LSM)+YSZ to separate O2 from air in the presence of these unavoidable gases for more advanced applications. To prepare the triple layer hollow fiber, the dual-layer fiber was firstly synthesized via a combined phase inversion and sintering method where the dense YSZ layer was present on top of the porous LSM-YSZ layer. We further deposited either porous Ag or its mixture with YSZ layer above the dense YSZ surface. The final fiber consists of three layers in sequence from outside surface to inside surface of Ag+YSZ/YSZ/LSM+YSZ. The dense central YSZ layer acts as the ionic conducting phase to prevent gas diffusion while the other two porous layers serve as the electronic conducting phase with catalytic effect to enhance the surface reaction kinetics. To overcome the electronic conductivity limitation of YSZ, silver (Ag) short circuit paste was additionally used to seal the membrane and electronically connect the outer and inner surfaces for electron shuttle for the two surface O2 exchange reactions. Ag-YSZ coated fiber performed better than Ag coated fiber and showed increasing fluxes from 0.1 to 0.53 mL min−1 cm−2 upon increasing temperature from 700 to 900 °C. The O2 fluxes remained constant irrespective of changing the sweep gas from pure He to its mixtures containing CO2, H2, or CH4; mirroring the membrane robustness to tolerate these gases at high temperatures