Navigation Accuracy Category-Position Models and Estimate Position Uncertainty Calculations for TIS-B System

AbstractNavigation accuracy category-position (NACp) is an important parameter for system accuracy of traffic information service-broadcast (TIS-B), which is determined by estimate position uncertainty (EPU). Centered about the problems that the existing EPU calculation based on noise measurement is low in accuracy and unfit for describing uncorrected biases in target reports, this article analyses the traditional NACp model, and uses the least square estimation (LSE) in EPU calculation. Furthermore, it proposes an extended NACp model, which considers both noise and biases and acquires EPU estimation with the help of approximate multiplex Taylor expression. Analysis and simulation show that the proposed method not only leads to significant improvement of the accuracy of EPU calculation, but is fit for EPU calculation with tracking biases in TIS-B system as well. As such it can find application in practice to depict different kinds of error models in TIS-B system

Evaluation of putative reference genes for gene expression normalization in soybean by quantitative real-time RT-PCR

<p>Abstract</p> <p>Background</p> <p>Real-time quantitative reverse transcription PCR (RT-qPCR) data needs to be normalized for its proper interpretation. Housekeeping genes are routinely employed for this purpose, but their expression level cannot be assumed to remain constant under all possible experimental conditions. Thus, a systematic validation of reference genes is required to ensure proper normalization. For soybean, only a small number of validated reference genes are available to date.</p> <p>Results</p> <p>A systematic comparison of 14 potential reference genes for soybean is presented. These included seven commonly used (<it>ACT2, ACT11, TUB4, TUA5, CYP, UBQ10, EF1b</it>) and seven new candidates (<it>SKIP16, MTP, PEPKR1, HDC, TIP41, UKN1, UKN2</it>). Expression stability was examined by RT-qPCR across 116 biological samples, representing tissues at various developmental stages, varied photoperiodic treatments, and a range of soybean cultivars. Expression of all 14 genes was variable to some extent, but that of <it>SKIP16, UKN1 </it>and <it>UKN2 </it>was overall the most stable. A combination of <it>ACT11, UKN1 </it>and <it>UKN2 </it>would be appropriate as a reference panel for normalizing gene expression data among different tissues, whereas the combination SKIP16, UKN1 and MTP was most suitable for developmental stages. <it>ACT11, TUA5 </it>and <it>TIP41 </it>were the most stably expressed when the photoperiod was altered, and <it>TIP41, UKN1 </it>and <it>UKN2 </it>when the light quality was changed. For six different cultivars in long day (LD) and short day (SD), their expression stability did not vary significantly with <it>ACT11, UKN2 </it>and <it>TUB4 </it>being the most stable genes. The relative gene expression level of <it>GmFTL3</it>, an ortholog of Arabidopsis <it>FT </it>(<it>FLOWERING LOCUS T</it>) was detected to validate the reference genes selected in this study.</p> <p>Conclusion</p> <p>None of the candidate reference genes was uniformly expressed across all experimental conditions, and the most suitable reference genes are conditional-, tissue-specific-, developmental-, and cultivar-dependent. Most of the new reference genes performed better than the conventional housekeeping genes. These results should guide the selection of reference genes for gene expression studies in soybean.</p

Data set for cloning and characterization of heterologous transporters in Saccharomyces cerevisiae and identification of important amino acids for xylose utilization

AbstractThe efficient uptake is important for the xylose utilization by Saccharomyces cerevisiae. A heterogenous transporter Mgt05196p was cloned from Meyerozyma guilliermondii and expressed in Saccharomyces cerevisiae [1]. This data article contains the transport characteristics of Mgt05196p in S. cerevisiae. The fluorescence of fusion protein Mgt05196p-GFP expressing strain was located on the cell surface demonstrated that the heterogenous transporter Mgt05196p was targeted to the plasma membrane of S. cerevisiae. The expressing of Mgt05196p in the hxt null S. cerevisiae endowed the strain with the glucose and d-xylose absorption capacity, as well as expressing the native d-xylose transporter Gal2p. The transmembrane domains of Mgt05196p were predicted and compared with the XylEp, whose crystal structure was revealed. And then, the homologous modeling of Mgt05196p was built basing on the XylEp to find out the crucial amino acid residues for sugars binding and transport

CT-based radiomics for predicting pathological grade in hepatocellular carcinoma

ObjectiveTo construct and validate radiomics models for hepatocellular carcinoma (HCC) grade predictions based on contrast-enhanced CT (CECT).MethodsPatients with pathologically confirmed HCC after surgery and underwent CECT at our institution between January 2016 and December 2020 were enrolled and randomly divided into training and validation datasets. With tumor segmentation and feature extraction, radiomic models were constructed using univariate analysis, followed by least absolute shrinkage and selection operator (LASSO) regression. In addition, combined models with clinical factors and radiomics scores (Radscore) were constructed using logistic regression. Finally, all models were evaluated using the receiver operating characteristic (ROC) curve with the area under the curve (AUC), calibration curve, and decision curve analysis (DCA).ResultsIn total 242 patients were enrolled in this study, of whom 170 and 72 formed the training and validation datasets, respectively. The arterial phase and portal venous phase (AP+VP) radiomics model were evaluated as the best for predicting HCC pathological grade among all the models built in our study (AUC = 0.981 in the training dataset; AUC = 0.842 in the validation dataset) and was used to build a nomogram. Furthermore, the calibration curve and DCA indicated that the AP+VP radiomics model had a satisfactory prediction efficiency.ConclusionsLow- and high-grade HCC can be distinguished with good diagnostic performance using a CECT-based radiomics model

On the use of an explicit chemical mechanism to dissect peroxy acetyl nitrate formation.

Peroxy acetyl nitrate (PAN) is a key component of photochemical smog and plays an important role in atmospheric chemistry. Though it has been known that PAN is produced via reactions of nitrogen oxides (NOx) with some volatile organic compounds (VOCs), it is difficult to quantify the contributions of individual precursor species. Here we use an explicit photochemical model--Master Chemical Mechanism (MCM) model--to dissect PAN formation and identify principal precursors, by analyzing measurements made in Beijing in summer 2008. PAN production was sensitive to both NOx and VOCs. Isoprene was the predominant VOC precursor at suburb with biogenic impact, whilst anthropogenic hydrocarbons dominated at downtown. PAN production was attributable to a relatively small class of compounds including NOx, xylenes, trimethylbenzenes, trans/cis-2-butenes, toluene, and propene. MCM can advance understanding of PAN photochemistry to a species level, and provide more relevant recommendations for mitigating photochemical pollution in large cities

Rural livelihoods and vulnerability to climate hazards in Ningxia, Northwest China

This study addresses how climate affects the livelihoods of people living in agricultural communities in Ningxia, one of the five autonomous regions in China. The analysis formed part of a vulnerability assessment to contribute to the development of an adaptation strategy for the region. Data were collected through questionnaires and focus group discussions in nine villages, three located in each of three different agro-ecosystems in the region. The survey results showed that drought has been a major hazard impacting rural livelihoods. Farmers in all three agro-ecosystems showed differing levels of vulnerability; susceptibility was higher, for instance, in the middle arid and southern rainfed mountainous areas, due to farmers’ greater exposure to climatic hazards and because a greater proportion of income originates from farming activities. Recent climate variability had affected many aspects of farmers’ livelihoods but it was not the only challenge they had faced. The perennially dry climate is a significant limiting factor for agricultural production in the region, greatly exacerbated by periodic reductions in moisture due to drought. Unsurprisingly, farmers have developed and continue to use a wide range of measures to retain and enhance soil moisture and to maintain agricultural production in this harsh environment: adaptation is an inherent feature of their behaviour, but their capacity to act is determined by a range of factors. When questioned on the constraints they faced respondents cited most often lack of money, water shortage and agricultural inputs. Because of the close alignment at the community and household level between adaptation and more generic individual and institutional aims for development there exists good potential to incorporate adaptation objectives and measures into mainstream development plans and poverty alleviation programmes

PCK1 Downregulation Promotes TXNRD1 Expression and Hepatoma Cell Growth via the Nrf2/Keap1 Pathway

Gluconeogenesis, generates glucose from small carbohydrate substrates, and drives the metabolic flux in parallel but opposite to glycolysis. The cytoplasmic isoform of phosphoenolpyruvate carboxykinase (PCK1 or PEPCK-C), a rate-limiting enzyme in gluconeogenesis, initiates the gluconeogenesis process and is reportedly dysregulated in multiple types of cancer. Gluconeogenesis mainly occurs in the liver during fasting, and previous studies have demonstrated that PCK1 acts as a tumor suppressor in hepatocellular carcinoma (HCC); however, the role of PCK1 in cancer progression remains incompletely understood. In the current study, we found that PCK1 expression was decreased in HCC as compared to adjacent normal liver tissues, and low PCK1 expression correlated with poor patient prognosis. Furthermore, overexpression of PCK1 suppressed reactive oxygen species (ROS) production and nuclear translocation of Nrf2 in hepatoma cells. In addition, thioredoxin reductase 1 (TXNRD1), an antioxidant enzyme regulated by the Nrf2/Keap1 pathway, was downregulated upon overexpression of PCK1 in HCC cell lines. Furthermore, we verified this axis using nude mouse xenograft model. Finally, we found that auranofin, a TXNRD1 inhibitor, enhanced the sensitivity of PCK1-knockout hepatoma cells to sorafenib-induced apoptosis. Taken together, our findings suggest that PCK1 deficiency promotes hepatoma cell proliferation via the induction of oxidative stress and the activation of transcription factor Nrf2, and that targeting the TXNRD1 antioxidant pathway sensitizes PCK1-knockout hepatoma cells to sorafenib treatment in vitro

Polluted dust promotes new particle formation and growth

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