23 research outputs found

    Laboratory Calibration of a Field Imaging Spectrometer System

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    A new Field Imaging Spectrometer System (FISS) based on a cooling area CCD was developed. This paper describes the imaging principle, structural design, and main parameters of the FISS sensor. The FISS was spectrally calibrated with a double grating monochromator to determine the center wavelength and FWHM of each band. Calibration results showed that the spectral range of the FISS system is 437–902 nm, the number of channels is 344 and the spectral resolution of each channel is better than 5 nm. An integrating sphere was used to achieve absolute radiometric calibration of the FISS with less than 5% calibration error for each band. There are 215 channels with signal to noise ratios (SNRs) greater than 500 (62.5% of the bands). The results demonstrated that the FISS has achieved high performance that assures the feasibility of its practical use in various fields

    Survey of Tyrosine Kinase Signaling Reveals ROS Kinase Fusions in Human Cholangiocarcinoma

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    Cholangiocarcinoma, also known as bile duct cancer, is the second most common primary hepatic carcinoma with a median survival of less than 2 years. The molecular mechanisms underlying the development of this disease are not clear. To survey activated tyrosine kinases signaling in cholangiocarcinoma, we employed immunoaffinity profiling coupled to mass spectrometry and identified DDR1, EPHA2, EGFR, and ROS tyrosine kinases, along with over 1,000 tyrosine phosphorylation sites from about 750 different proteins in primary cholangiocarcinoma patients. Furthermore, we confirmed the presence of ROS kinase fusions in 8.7% (2 out of 23) of cholangiocarcinoma patients. Expression of the ROS fusions in 3T3 cells confers transforming ability both in vitro and in vivo, and is responsive to its kinase inhibitor. Our data demonstrate that ROS kinase is a promising candidate for a therapeutic target and for a diagnostic molecular marker in cholangiocarcinoma. The identification of ROS tyrosine kinase fusions in cholangiocarcinoma, along with the presence of other ROS kinase fusions in lung cancer and glioblastoma, suggests that a more broadly based screen for activated ROS kinase in cancer is warranted

    Establishment of the Lunar Phase Morphological Classification for Cervical Spinal Canal

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    Study Design Retrospective clinical trial. Purpose To establish a morphological classification of the cervical spinal canal using its parameters. Overview of Literature Cervical spine computed tomography (CT) data of 200 healthy volunteers in 2 years were analyzed. The morphology of the spinal cord was also analyzed. Methods The median sagittal diameter and transverse diameter of the spinal canal from C2 to C7 were measured on CT images. The ratio of the median sagittal diameter to the transverse diameter was calculated. Accordingly, the spinal canal shape of each segment was classified into four, and the specific criteria of lunar phase classification were determined through linear discriminant analysis based on the ratio of the median sagittal diameter to the transverse diameter. The inter-rater reliability of the classification was explored using Kappa coefficients. Finally, the morphology of the different segments of the cervical spinal canal in healthy volunteers was revised and compared. Results According to the ratio of the median sagittal diameter and the transverse diameter of the cervical spinal canal, the lunar phase classification of the cervical bony spinal canal was determined as follows: full-moon >0.65, 0.550.05). The frequency of the spinal canal of the residual-moon type was the highest, and the full-moon (6.5%) and residual-moon (7.5%) types of C7 were rare. Conclusions The morphological classification of the cervical spinal canal was established to present anatomical variations. The classification showed good inter-rater reliability

    GPM-Based Multitemporal Weighted Precipitation Analysis Using GPM_IMERGDF Product and ASTER DEM in EDBF Algorithm

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    To obtain the high-resolution multitemporal precipitation using spatial downscaling technique on a precipitation dataset may provide a better representation of the spatial variability of precipitation to be used for different purposes. In this research, a new downscaling methodology such as the global precipitation mission (GPM)-based multitemporal weighted precipitation analysis (GMWPA) at 0.05° resolution is developed and applied in the humid region of Mainland China by employing the GPM dataset at 0.1° and the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) 30 m DEM-based geospatial predictors, i.e., elevation, longitude, and latitude in empirical distribution-based framework (EDBF) algorithm. The proposed methodology is a two-stepped process in which a scale-dependent regression analysis between each individual precipitation variable and the EDBF-based weighted precipitation with geospatial predictor(s), and to downscale the predicted multitemporal weighted precipitation at a refined scale is developed for the downscaling of GMWPA. While comparing results, it shows that the weighted precipitation outperformed all precipitation variables in terms of the coefficient of determination (R2) value, whereas they outperformed the annual precipitation variables and underperformed as compared to the seasonal and the monthly variables in terms of the calculated root mean square error (RMSE) value. Based on the achieved results, the weighted precipitation at the low-resolution (e.g., at 0.75° resolution) along-with the original resolution (e.g., at 0.1° resolution) is employed in the downscaling process to predict the average multitemporal precipitation, the annual total precipitation for the year 2001 and 2004, and the average annual precipitation (2001–2015) at 0.05° resolution, respectively. The downscaling approach resulting through proposed methodology captured the spatial patterns with greater accuracy at higher spatial resolution. This work showed that it is feasible to increase the spatial resolution of a precipitation variable(s) with greater accuracy on an annual basis or as an average from the multitemporal precipitation dataset using a geospatial predictor as the proxy of precipitation through the weighted precipitation in EDBF environment

    Human Activity Coupled With Climate Change Strengthens the Role of Lakes as an Active Pipe of Dissolved Organic Matter

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    Abstract Dissolved organic matter (DOM) composition in lakes is controlled by multiple environmental drivers, but the relative importance of various drivers remains poorly understood at the continental scale. Here, we established a model resolving possible influencing pathways of climate, land cover, societal development, and water retention time of lakes on the quantity and quality of chromophoric DOM (CDOM) from 182 lakes spanning across strong climatic and economic gradients in China. Our results indicate that land cover and societal development both exhibit positive direct effects on lake CDOM quantity, highlighting the significant role of well‐vegetated soils and anthropogenic activities as sources of lake DOM on a continental scale. Climate has two strong but opposite effects—a warming and wet climate facilitates soil OM production and export, while it also enhances CDOM in‐lake transformation. Three proxies are proposed as indicators of the magnitude of biogeochemical drivers influencing lake DOM across different ecoclimatic zones, including fluorescent DOM/DOC indicating economic activity, percentages of a degraded fluorescent DOM component indicating solar irradiation, and percent tyrosine‐like DOM reflecting DOM processing time within the watershed and lake. Collectively, our findings indicate that the effects of climate change and rapid societal development will result in increased loadings of terrestrial and anthropogenic DOM into lakes and drive higher rates of within‐lake processing of DOM. Consequently, lakes will play a more important role as an “active pipe” in mediating the flux and transformation of organic carbon, intensifying the coupling between terrestrial and aquatic carbon cycles on a continental scale

    Carbon Dynamics and Community Production in the Mississippi River Plume

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    Dissolved inorganic carbon (DIC), total alkalinity (TAlk), pH, and dissolved oxygen (DO) were determined in the Mississippi River plume during five cruises conducted in the spring, summer, and fall. In contrast to many other large rivers, both DIC and TAlk were higher in river water than in seawater. Substantial losses of DIC, relative to TAlk, occurred within the plume, particularly at intermediate salinities. DIC removal was accompanied by high DO, high pH, and nutrient depletion, and was attributed to high phytoplankton production. As a result, the carbonate saturation in the plume became much higher than in ocean and river waters. A mixing model was used to determine DIC removal. We provide evidence that the use of a two-end-member (river and ocean) mixing model was valid during late summer and fall (low discharge period). However, for other periods we used salinity and TAlk to delineate a mixing model that included two river end members and an ocean end member. Net community production rates in the plume, estimated using a box model, peaked in the summer and were among the highest reported to date for large river plumes. In the summer and fall, biological production in the river plume consumed a majority of the available nutrients, whereas during the spring only a small fraction of the available nutrients were consumed in the plume. Biological production was the dominant process influencing pH and carbonate saturation state along the river-ocean gradient, whereas physicochemical dynamics of mixing played an important role in controlling the TAlk and DIC distributions of this large river plume

    Achieving a high magnetization in sub-nanostructured magnetite films by spin-flipping of tetrahedral Fe3+ cations

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    Magnetite Fe3O4 (ferrite) has attracted considerable interest for its exceptional physical properties: It is predicted to be a semimetallic ferromagnetic with a high Curie temperature, it displays a metal-insulator transition, and has potential oxide-electronics applications. Here, we fabricate a high-magnetization (> 1 Tesla) high-resistance (similar to 0.1 Omega center dot cm) sub-nanostructured (grain size < 3 nm) Fe3O4 film via grain-size control and nano-engineering. We report a new phenomenon of spin-flipping of the valence-spin tetrahedral Fe3+ in the sub-nanostructured Fe3O4 film, which produces the high magnetization. Using soft X-ray magnetic circular dichroism and soft X-ray absorption, both at the Fe L-3,L-2- and O K-edges, and supported by first-principles and charge-transfer multiple calculations, we observe an anomalous enhancement of double exchange, accompanied by a suppression of the superexchange interactions because of the spin-flipping mechanism via oxygen at the grain boundaries. Our result may open avenues for developing spin-manipulated giant magnetic Fe3O4-based compounds via nano-grain size control
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