22 research outputs found

    Laparoscopic cytoreductive nephrectomy is associated with significantly improved survival compared with open cytoreductive nephrectomy or targeted therapy alone

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    The aim of the present study was to compare the survival outcomes for patients with metastatic renal cell carcinoma (mRCC) who underwent laparoscopic cytoreductive nephrectomy (CN) vs. open CN vs. targeted therapy (TT) alone at our institution. A retrospective chart review was performed at our institution for patients who underwent CN prior to TT (laparoscopic, n=48; open, n=48) or who were deemed unfit for surgery and received TT alone (n=36), between January 2007 and December 2012. Kaplan-Meier estimated survival and Cox proportional hazards analyses were performed. Laparoscopic CN was associated with significantly longer survival compared with open CN or TT alone (median survival 24 vs. \u3c12 months, respectively; P\u3c0.01). On multivariate analysis, laparoscopic CN was an independent predictor of survival [hazard ratio (HR)=0.48, P\u3c0.01), controlling for preoperative risk factors, while survival was similar between open CN and TT alone (HR=0.85, P=0.54). In our experience, laparoscopic CN appears to be a significant predictor of survival in mRCC. Selection bias of the surgeon for patients with improved survival may account for clinical variables that were otherwise difficult to quantify. For patients who were not candidates for laparoscopic CN, open CN did not confer a survival benefit over TT alone, while it was associated with increased morbidity

    A flight test of the strapdown airborne gravimeter SGA-WZ in Greenland

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    An airborne gravimeter is one of the most important tools for gravity data collection over large areas with mGal accuracy and a spatial resolution of several kilometers. In August 2012, a flight test was carried out to determine the feasibility and to assess the accuracy of the new Chinese SGA-WZ strapdown airborne gravimeter in Greenland, in an area with good gravity coverage from earlier marine and airborne surveys. An overview of this new system SGA-WZ is given, including system design, sensor performance and data processing. The processing of the SGA-WZ includes a 160 s length finite impulse response filter, corresponding to a spatial resolution of 6 km. For the primary repeated line, a mean r.m.s. deviation of the differences was less than 1.5 mGal, with the error estimate confirmed from ground truth data. This implies that the SGA-WZ could meet standard geophysical survey requirements at the 1 mGal level

    Can time-series Sentinel images be used to properly identify wetland plant communities?

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    Understanding the distribution of wetland plant communities is critical to biodiversity conservation and wetland habitat sustainable management, especially for migratory birds. However, limited road accessibility and low spectral discriminability make the mapping of wetland plant communities inadequate for wetland health assessment, necessitating the improvement of classification methods. In this study, we proposed a random forest classifier that combined multi-source remote sensing features for wetland plant community classification and evaluated this method for the Momoge Ramsar wetland site (MRWS) in China. The major result of this work was that the phenological and time-series features based on Sentinel-2 images were the most valuable discriminators for wetland plant community classification in the MRWS. The SAR_sum extracted from Sentinel-1 images also had high importance for classification. Moreover, the spatial pattern of different wetland plant communities was revealed, and the resultant classification map had a high overall accuracy (91.3%) and Kappa coefficient (0.90). And the six important features prompted the classification accuracy to reach 84.8%. In 2020, the total coverage area of natural wetland plant communities in MRWS reached 628.5 km2 (42.1%), of which Carex meyeriana distributed the most widely, followed by Suaeda glauca, Phragmites australis, Typha orientalis, and Scirpus triquater. The findings of this study can provide scientific decision-making support for the protection and management of migratory birds and plants in the MRWS. The proposed method employed freely available Sentinel 1/2 satellite images and fully automated programs on Google Earth Engine, and has guiding significance for large-scale and long-time-series wetland classification

    An Enveloping, Centering, and Grabbing Mechanism for Harvesting Hydroponic Leafy Vegetables Cultivated in Pipeline

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    Manually harvesting hydroponic leafy vegetables from a cultivation pipeline is labor-intensive and expensive. Rapidly grabbing hydroponic leafy vegetables grown in different positions and orientations in the planting hole is the primary issue for efficient mechanical harvesting. Thus, a novel grabbing mechanism with double-pivot rotation cross fingers is proposed. The fingers’ inner surfaces could envelop the grabbable area of the leafy vegetable in the grasping process and position each leafy vegetable stalk to the center of the planting hole before taking it out. A grabbing mechanism for harvesting hydroponic Chinese kale was designed and optimized with less than 1 mm of grasping error, enough enveloping range, and no collision with the extended leaves. Laboratory experiments were conducted to investigate centering and grabbing at different initial positions and inclination angles of the hydroponic Chinese kale and varied finger deflection speeds. It was indicated that for the grasping inclination angle and grabbing success rate, the initial inclination angle was a significant factor, as was the position, whereas the finger deflection speed was insignificant. As the initial inclination angle of matured hydroponic Chinese kale in different initial positions is mostly larger than 60°, the best results were achieved with a finger deflection speed in the range of 40° s−1 to 60° s−1 and grasping inclination angles of 85° to 95°, with a grabbing success rate of more than 95%. This showed the promising applicability of the studied grabbing mechanism for harvesting hydroponic Chinese kale or other varieties of leafy hydroponic vegetables with similar growth characteristics

    Airborne Gravity Data Denoising Based on Empirical Mode Decomposition: A Case Study for SGA-WZ Greenland Test Data

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    Surveying the Earth’s gravity field refers to an important domain of Geodesy, involving deep connections with Earth Sciences and Geo-information. Airborne gravimetry is an effective tool for collecting gravity data with mGal accuracy and a spatial resolution of several kilometers. The main obstacle of airborne gravimetry is extracting gravity disturbance from the extremely low signal to noise ratio measuring data. In general, the power of noise concentrates on the higher frequency of measuring data, and a low pass filter can be used to eliminate it. However, the noise could distribute in a broad range of frequency while low pass filter cannot deal with it in pass band of the low pass filter. In order to improve the accuracy of the airborne gravimetry, Empirical Mode Decomposition (EMD) is employed to denoise the measuring data of two primary repeated flights of the strapdown airborne gravimetry system SGA-WZ carried out in Greenland. Comparing to the solutions of using finite impulse response filter (FIR), the new results are improved by 40% and 10% of root mean square (RMS) of internal consistency and external accuracy, respectively

    Hyperspectral and Multispectral Image Fusion via Nonlocal Low-Rank Tensor Decomposition and Spectral Unmixing

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    Hyperspectral (HS) imaging has shown its superiority in many real applications. However, it is usually difficult to obtain high-resolution (HR) HS images through existing imaging techniques due to the hardware limitations. To improve the spatial resolution of HS images, this article proposes an effective HS-multispectral (HS-MS) image fusion method by combining the ideas of nonlocal low-rank tensor modeling and spectral unmixing. To be more precise, instead of unfolding the HS image into a matrix as done in the literature, we directly represent it as a tensor, then a designed nonlocal Tucker decomposition is used to model its underlying spatial-spectral correlation and the spatial self-similarity. The MS image serves mainly as a data constraint to maintain spatial consistency. To further reduce the spectral distortions in spatial enhancement, endmembers, and abundances from the spectral are used for spectral regularization. An efficient algorithm based on the alternating direction method of multipliers (ADMM) is developed to solve the resulting model. Extensive experiments on four HS image data sets demonstrate the superiority of the proposed method over several state-of-theart HS-MS image fusion methods

    Analysis of Factors Affecting Optical Performance of GaN-Based Micro-LEDs with Quantum Dots Films

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    Optical performance in terms of light efficiency, color crosstalk and ambient contrast ratio were analyzed for blue GaN-based micro-light emitting diodes (micro-LEDs) combined with red/green quantum dots (QDs)-polymethyl methacrylate (PMMA) films. The thickness and mass ratio of QDs films are two critical factors in affecting the performance of micro-LEDs. Firstly, the precise optical modeling of QDs-PMMA films is established based on the double integrating sphere (DIS) testing system and inverse adding doubling algorithm (IADA) theory. Red and green QDs-PMMA films are composed of ZnCdSe/ZnS QDs and green ZnCdSeS/ZnS QDs, respectively. The fundamental optical parameters of QDs-PMMA films, including scattering, absorption and anisotropy coefficients, are obtained successfully. Secondly, based on these optical parameters, the Monte Carlo ray tracing method is applied to analyze the effect of a QDs-PMMA film’s thickness and mass ratio on the optical performance of micro-LEDs. Results reveal that the light efficiency first increases and then decreases with the increase of a QDs film’s thickness or mass ratio, owing to the scattering characteristics of QDs. Different from the variation tendencies of light efficiency, the crosstalk between adjacent pixels increases as the QDs-PMMA film’s thickness or mass ratio increases, and the ambient contrast ratio is kept stable when the thickness increases. The mass ratio variation of QDs film can change the optical performance of micro-LEDs more effectively than thickness, which demonstrates that mass ratio is a more important factor affecting the optical performance of micro-LEDs

    Genome-wide identification of MAPK family in papaya (Carica papaya) and their involvement in fruit postharvest ripening

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    Abstract Background Papaya (Carica papaya) is an economically important fruit cultivated in the tropical and subtropical regions of China. However, the rapid softening rate after postharvest leads to a short shelf-life and considerable economic losses. Accordingly, understanding the mechanisms underlying fruit postharvest softening will be a reasonable way to maintain fruit quality and extend its shelf-life. Results Mitogen-activated protein kinases (MAPKs) are conserved and play essential roles in response to biotic and abiotic stresses. However, the MAPK family remain poorly studied in papaya. Here, a total of nine putative CpMAPK members were identified within papaya genome, and a comprehensive genome-wide characterization of the CpMAPKs was performed, including evolutionary relationships, conserved domains, gene structures, chromosomal locations, cis-regulatory elements and expression profiles in response to phytohormone and antioxidant organic compound treatments during fruit postharvest ripening. Our findings showed that nearly all CpMAPKs harbored the conserved P-loop, C-loop and activation loop domains. Phylogenetic analysis showed that CpMAPK members could be categorized into four groups (A-D), with the members within the same groups displaying high similarity in protein domains and intron–exon organizations. Moreover, a number of cis-acting elements related to hormone signaling, circadian rhythm, or low-temperature stresses were identified in the promoters of CpMAPKs. Notably, gene expression profiles demonstrated that CpMAPKs exhibited various responses to 2-chloroethylphosphonic acid (ethephon), 1-methylcyclopropene (1-MCP) and the combined ascorbic acid (AsA) and chitosan (CTS) treatments during papaya postharvest ripening. Among them, both CpMAPK9 and CpMAPK20 displayed significant induction in papaya flesh by ethephon treatment, and were pronounced inhibition after AsA and CTS treatments at 16 d compared to those of natural ripening control, suggesting that they potentially involve in fruit postharvest ripening through ethylene signaling pathway or modulating cell wall metabolism. Conclusion This study will provide some valuable insights into future functional characterization of CpMAPKs, and hold great potential for further understanding the molecular mechanisms underlying papaya fruit postharvest ripening

    Mapping Phragmites australis Aboveground Biomass in the Momoge Wetland Ramsar Site Based on Sentinel-1/2 Images

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    Phragmites australis (P. australis) is one of the most important plant species found in wetland ecosystems, and its aboveground biomass (AGB) is a key indicator for assessing the quality or health of a wetland site. In this study, we combined Sentinel-1/2 images and field observation data collected in 2020, to delineate the distribution of P. australis in the Momoge Ramsar Wetland site by using a random forest method, and further, to estimate AGB by comparing multiple linear regression models. The results showed that the overall classification accuracy of P. australis using the random forest method was 89.13% and the P. australis area in the site was 135.74 km2 in 2020. Among various remote sensing variables, the largest correlation coefficient was observed between dry weight of AGB of P. australis and Sentinel-2 red edge B7, and between fresh weight of P. australis AGB and red edge B5. The optimal models for estimating dry and fresh weight of P. australis AGB were multiple linear regression models, with an accuracy of 75.4% and 69.2%, respectively. In 2020, it was estimated that the total fresh weight of P. australis AGB in this Ramsar site was 21.2 × 107 kg and the total dry weight was 7.2 × 107 kg. The larger weight of P. australis AGB was identified mainly at central and western sites. The application of Sentinel-2 red-edge band for AGB estimation can significantly improve the model estimation accuracy. The findings of this study will provide a scientific basis for the management and protection of wetland ecosystems and sustainable utilization of P. australis resources
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