Estimation of GPS Differential Code Biases Based on Independent Reference Station and Recursive Filter

The differential code bias (DCB) of the Global Navigation Satellite Systems (GNSS) receiver should be precisely corrected when conducting ionospheric remote sensing and precise point positioning. The DCBs can usually be estimated by the ground GNSS network based on the parameterization of the global ionosphere together with the global ionospheric map (GIM). In order to reduce the spatial-temporal complexities, various algorithms based on GIM and local ionospheric modeling are conducted, but rely on station selection. In this paper, we present a recursive method to estimate the DCBs of Global Positioning System (GPS) satellites based on a recursive filter and independent reference station selection procedure. The satellite and receiver DCBs are estimated once per local day and aligned with the DCB product provided by the Center for Orbit Determination in Europe (CODE). From the statistical analysis with CODE DCB products, the results show that the accuracy of GPS satellite DCB estimates obtained by the recursive method can reach about 0.10 ns under solar quiet condition. The influence of stations with bad performances on DCB estimation can be reduced through the independent iterative reference selection. The accuracy of local ionospheric modeling based on recursive filter is less than 2 Total Electron Content Unit (TECU) in the monthly median sense. The performance of the recursive method is also evaluated under different solar conditions and the results show that the local ionospheric modeling is sensitive to solar conditions. Moreover, the recursive method has the potential to be implemented in the near real-time DCB estimation and GNSS data quality chec

L1-ORF1p and Ago2 are involved in a siRNA-mediated regulation for promoter activity of L1-5’UTR

Introduction. Long interspersed nuclear elements-1 (L1), as the only one self-active retrotransposon of the mobile element, was found to be generally activated in tumor cells. The 5‘UTR of L1 (L1-5’UTR) contains both sense and antisense bidirectional promoters, transcription products of which can generate double-strand RNA (dsRNA). In addition, L1-ORF1p, a dsRNA binding protein encoded by L1, is considered to engage in some RNA-protein (RNP) formation. Ago2, one of the RISC components, can bind to dsRNA to form RISC complex, but its role in L1 regulation still remains unclear. Due that the 5‘UTR of L1 (L1-5’UTR) contains both sense and antisense bidirectional promoters, so the activities in both string were identified. A dsRNA-mediated regulation of L1-5’UTR, with the feedback regulation of L1-ORF1p as well as other key molecules engaged (Ago1–4) in this process, was also investigated. Material and methods. Genomic DNA was extracted from HEK293 cells and subjected to L1-5’UTR prepa­ration by PCR. Report gene system pIRESneo with SV40 promoter was employed. The promoter activities of different regions in L1-5’UTR were identified by constructing these regions into pIRESneo, which SV40 region was removed prior, to generate different recombinant plasmids. The promoter activities in recombinant plasmids were detected by the luciferase expression assay. Western blot and co-immunoprecipitation were employed to identify proteins expression and protein-protein interaction respectively. Results. Ago2 is a member of Agos family, which usually forms a RISC complex with si/miRNA and is involved in post- transcriptional regulation of many genes. Here L1-ORF1p and Ago2 conducts a regulation as a negative feedback for L1-5'UTR sense promoter. L1-ORF1p could form the immune complexes with Ago1, Ago2 and Ago4, respectively. Conclusions. L1-5’UTR harbors both sense and antisense promoter activity and a dsRNA-mediated regulation is responsible for L1-5’UTR regulation. Agos proteins and L1-ORF1p were engaged in this process

The four-dimensional variational Neustrelitz Electron Density Assimilation Model: NEDAM

With the development of the Global Navigation Satellite System (GNSS) and regional augmentation systems, the influence of the ionosphere on GNSS signals is becoming increasingly important. It is also of particular interest to retrieve the electron density distribution from GNSS observations. We have successfully developed a four-dimensional variational assimilation scheme, the Neustrelitz Electron Density Assimilation Model (NEDAM), and verified NEDAM by a simulation study using a European ground-based GNSS network. The performance of NEDAM is validated using two ionosondes and COSMIC-1 radio occultation observations during the September 2017 geomagnetic storm period. The critical frequency of the F2 layer in NEDAM is much more accurate than that of a physics-based model driven by observed geophysical indices or the Neustrelitz Electron Density Model (NEDM), when compared to data from two ionosondes. During the storm, the root mean square error of the F2-layer critical frequency with respect to the two ionosondes is improved by 0.54 and 0.42 MHz, respectively. We also compare two co-located electron density profiles from the COSMIC-1 mission with NEDAM and NEDM. It is found that NEDAM is able to reconstruct well not only the peak density but also the peak density height, which is missing in the previous research

Relationships between structure and antioxidant capacity and activity of glycosylated flavonols

The antioxidant capacity (AC) and antioxidant activity (AA) of three flavonols (FLV), aglycones and their glycosylated derivatives were evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays in various solvents. Findings confirmed that the glycosylation at the 3-position (3-glycosylation) always decreased the AC under most conditions due to substitution of the 3-position hydroxyl group and glycoside disruption in the molecular planarity. The 7-glycosylated derivatives did not have the above effects, thus generally exhibited ACs similar to their aglycones. Glycosylation decreased the AA of kaempferol and isorhamnetin for both assays in methanol, 3-glycosylation inhibited quercetin AA in the ABTS assay. In the DPPH assay, the AA of 3-glycosylated quercetin was significantly higher than quercetin. Using LC–MS/MS analysis, we found that quercetin and quercetin-7-glucoside underwent dimerization during the antioxidant reaction, potentially leading to a decline in AAs. However, 3-glycoside substitution may have hindered dimer formation, thereby allowing the FLVs to retain strong free radical scavenging abilities.National Key Research and Development Program of China | Ref. 2019YFC160670

A novel hybrid energy system combined with solar-road and soil-regenerator: Dynamic model and operational performance

This document is the Accepted Manuscript version, made available under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives License CC BY NC-ND 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/). Under embargo until 26 November 2018. The final, definitive version of this article is available online at doi: https://doi.org/10.1016/j.enconman.2017.11.066.Solar roads are emergent and huge energy source in traffic domains. To improve the energy utilization efficiency of a solar road, a novel solar-road and soil-regenerator hybrid energy system in combination with conventional photovoltaic-thermal and soil heat storage technology was proposed. A mathematical model of the solar-road and soil-regenerator hybrid energy system was developed, validated, and applied to evaluate the thermal storage and power generation performance of the proposed system in cold regions. The results indicated that for critical thermal storage temperatures of 20, 30, and 40 °C, the proposed system decreased maximum photovoltaic cell temperatures by 24.09, 25.84, and 24.42 °C and increased electrical efficiencies by 6.85, 6.68, and 4.53%, respectively, compared with conventional solar roads. By storing heat in the soil and elevating soil temperatures, the proposed system also increased the average borehole wall temperatures by 2.93, 2.26, 1.87 °C. The proposed system produced overall energy efficiencies of 48.42, 55.47, and 66.58%, while conventional solar road efficiencies approximate 10.75%.Peer reviewe