156 research outputs found

    Image Retrieval Method Combining Bayes and SVM Classifier Based on Relevance Feedback with Application to Small-scale Datasets

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    A vast amount of images has been generated due to the diversity and digitalization of devices for image acquisition. However, the gap between low-level visual features and high-level semantic representations has been a major concern that hinders retrieval accuracy. A retrieval method based on the transfer learning model and the relevance feedback technique was formulated in this study to optimize the dynamic trade-off between the structural complexity and retrieval performance of the small- and medium-scale content-based image retrieval (CBIR) system. First, the pretrained deep learning model was fine-tuned to extract features from target datasets. Then, the target dataset was clustered into the relative and irrelative image library by exploring the Bayes classifier. Next, the support vector machine (SVM) classifier was used to retrieve similar images in the relative library. Finally, the relevance feedback technique was employed to update the parameters of both classifiers iteratively until the request for the retrieval was met. Results demonstrate that the proposed method achieves 95.87% in classification index F1 - Score, which surpasses that of the suboptimal approach DCNN-BSVM by 6.76%. The performance of the proposed method is superior to that of other approaches considering retrieval criteria as average precision, average recall, and mean average precision. The study indicates that the Bayes + SVM combined classifier accomplishes the optimal quantities more efficiently than only either Bayes or SVM classifier under the transfer learning framework. Transfer learning skillfully excels training from scratch considering the feature extraction modes. This study provides a certain reference for other insights on applications of small- and medium-scale CBIR systems with inadequate samples

    WTC2005-64026 A MOLECULAR DYNAMICS STUDY ON THE STATIC AND DYNAMIC PROPERTIES OF LUBRICANT PFPE IN HARD DISK DRIVER

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    ABSTRACT The static and dynamic properties of lubricant PFPE are important for the service durability and reliability of the computer head-disk device. Thus molecular dynamic simulations based on a coarse-grained, bead-spring model are adopted to study those properties. On the one hand, we investigate the static properties and infer the structure of both nonpolar and polar PFPE films. For a nonpolar PFPE film, there is a layering structure in the surface layer. And for a polar PFPE film, besides layering structure, there is a bi-polymer structure in the bulk layer. On the other hand, we investigate the dynamic properties and find that for nonpolar PFPE film, a precursor film around one atomic diameter thickness develops according to layering structure; while for polar PFPE film, besides a precursor film, a much steeper and slower spreading shape appears according to bi-polymer structure

    Long-term effects of restoration on the links between above-and belowground biodiversity in degraded Horqin sandy grassland, Northern China

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    Long-term ecological restoration plays an important role in the sustainable development of degraded grassland ecosystem. In this study, the levels of species diversity, genetic diversity and soil microbial diversity in restored grassland were measured by vegetation survey, DNA barcoding and soil microbial high-throughput sequencing technology, so as to explore the relationship between above- and belowground biodiversity and its driving factors in Horqin sandy grassland. In this study, the results found that herb are dominated in restoration grassland types. Plant species richness (SR) from post-non-grazing restoration plot (NGR) communities was significantly higher than other restoration communities (10 ± 1.1, p = 0.004). Genetic diversity indices of dominant plant species in chloroplast DNA (cpDNA), were remarkable greater than nuclear DNA (nrDNA) in each recovering sandy grassland plots (amplitude of difference was 44.8%–70.5% in allelic richness (AR), 81.9%–128.1% in expected heterozygosity (HE)). The soil bacterial and fungal richness from natural mobile dune grassland (NM) communities was notably lower than that from recovering grassland types (1641.9 ± 100.4, p < 0.001; 533 ± 16.6, p < 0.001). In this study, heterogeneous levels of genetic variability among different recovering sandy grassland types were detected. Correlation analyses revealed that there were positive correlations between species diversity and genetic diversity (SR & AR: r = 0.56, R2 = 0.31, p < 0.001; SR & HE: r = 0.33, R2 = 0.11, p = 0.045) and a negative correlation between soil microbial diversity and genetic diversity (r = -0.44, R2 = 0.19, p = 0.005). The final structural equation model explained 38% of the variance in SR, 57% in AR, 52% in soil microbial diversity (SD), 49% in aboveground biomass (AGB), 87% in soil organic carbon (SOC), 47% in soil alkali-hydrolyzable nitrogen (SAN) and 69% in soil available phosphorus (SOP). Long-term ecological restoration had significant direct positive effects on AGB, SOC, SAN, SOP, AR, SR and SD. There was a negative correlation between above- and belowground biodiversity and biological and abiotic factors. The results of this study have clarified the above- and underground biodiversity levels of sandy grassland and the relationship with driving factors under long-term ecological restoration measures, and will provide effective support for the management and sustainable development of sandy grassland

    137Caesium, 40Potassium and potassium in raw and deep-oil stir-fried mushroom meals from Yunnan in China

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    A number of wild, edible mushroom species (Baorangia bicolor, Boletus calopus, Boletus obsclereumbrinus, Butyriboletus roseoflavus, Rubroboletus sinicus, Rugiboletus extremiorientalis and Xerocomus sp.) were collected in 2017, from Yunnan (Yuxi prefecture) in SW China. Samples of raw and stir-fried pools of these specimens were analysed for radioisotopes 137Cs (caesium) and 40 K (potassium), and for total K concentrations. On a whole (wet) weight (ww) basis, 137Cs activity ranged from <0.10 to 0.75 Bq kg−1 for raw, and from 0.5 to 4.4 Bq kg-1 in stir-fried mushrooms. Radiopotassium (40K) activity ranged from 57 to 96 Bq kg−1 ww for raw, and 170 to 370 Bq kg−1 ww for stir-fried mushrooms, while the corresponding concentration ranges for total K were 2100–3400 mg kg−1 ww (mean: 2800 ± 3900 mg kg−1 ww), and 6000–13000 mg kg−1 ww) mean: 8700 ± 2100 mg kg−1 ww), respectively. This data indicates that mushrooms from this region show negligible 137Cs contamination with evidently higher activity levels of 40K. The deep oil stir-frying process results in enrichment in the resulting meals for all three determinants. 100 g meal portions showed 137Cs activity in the range <0.08 to 0.44 Bq 100 g−1 ww (mean 0.15 ± 0.12 Bq 100 g−1 ww), and 40K activity from 16 to 37 Bq 100 g−1 ww (mean 24 ± 6 Bq 100 g−1 ww). The consequent exposure from 40K contained in a single 100 g serving and weekly (100 g x7) servings was equivalent to radiation doses in the range of 0.099 to 0.23 µSv and 0.68–1.6 µSv per capita (means 0.15 ± 0.04 and 1.1 ± 0.3 µSv). This is equivalent to doses in the range of 0.0017 to 0.0038 µSv kg-1 bm day-1 and 0.011 to 0.027 µSv kg-1 bm week-1 respectively (mean values of 0.0025 ± 0.006 µSv kg-1 bm day-1and 0.018 ± 0.004 µSv kg-1 bm week-1). Analogically to the annual 137Cs radiation exposure resulting from high rates of annual consumption (20–24 kg per capita), the estimated annual dose of radiation from 40K would range from 0.34 up to 0.92 µSv kg-1 bm (mean 0.60 µSv kg-1 bm). Thus in practice, high annual consumption rates of wild, stir-fried mushrooms as seen in Yunnan, would result in negligible internal doses from decay of artificial 137Cs, relative to that from natural 40K. The 100 g servings also contained between 590–1300 mg K making this local food one of the top dietary sources of nutritionally important potassium for local consumers

    Reference Ranges and Association of Age and Lifestyle Characteristics with Testosterone, Sex Hormone Binding Globulin, and Luteinizing Hormone among 1166 Western Chinese Men

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    Decreased total testosterone (TT) is the recommended metric to identify age-related hypogonadism. However, average TT and the extent to which it varies by age, can vary substantially among different populations. Population-specific reference ranges are needed to understand normal versus abnormal TT levels. Therefore, the goal for this study was to describe androgen concentrations and their correlates among Western Chinese men. We completed a population-based, cross-sectional study including 227 young adults (YA) (20–39 years) and 939 older adults (OA) (40–89 years). We measured TT, sex-hormone binding globulin (SHBG), luteinizing hormone (LH), testosterone secreting index (TSI), and calculated free testosterone (cFT). Reference ranges for this population were determined using average YA concentrations. Multivariable regression models were used to predict hormone concentrations adjusting for age, waist-to-height ratio (WHR), marital status, education, occupation, smoking, alcohol, blood glucose, and blood pressure. Among OA, 3.8% had low TT, 15.2% had low cFT, 26.3% had low TSI, 21.6% had high SHBG, and 6.1% had high LH. Average cFT was significantly lower in OA (0.30 nmol/L; standard deviation (SD): 0.09) versus YA (0.37; SD: 0.11) but TT was not different in OA (16.82 nmol/L; SD: 4.80) versus YA (16.88; SD: 5.29). In adjusted models increasing age was significantly associated with increased SHBG or LH, and decreased cFT or TSI; however, TT was not significantly associated with age (β = 0.02 nmol/L; 95% confidence interval (CI): -0.01, 0.04). Higher WHR was associated with significantly decreased TT, SHBG, TSI, and LH. The only variable significantly related to cFT was age (β = -0.0033; 95% CI:-0.0037, -0.0028); suggesting that cFT measurements would not be confounded by other lifestyle factors. In conclusion, cFT, but not TT, varies with age in this population, suggesting cFT may be a better potential marker for age-related androgen deficiency than TT among Western Chinese men

    Twist Promotes Tumor Metastasis in Basal-Like Breast Cancer by Transcriptionally Upregulating ROR1

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    Rationale: Twist is a key transcription factor for induction of epithelial-mesenchymal transition (EMT), which promotes cell migration, invasion, and cancer metastasis, confers cancer cells with stem cell-like characteristics, and provides therapeutic resistance. However, the functional roles and targeted genes of Twist in EMT and cancer progression remain elusive. Methods: The potential targeted genes of Twist were identified from the global transcriptomes of T47D/Twist cells by microarray analysis. EMT phenotype was detected by western blotting and immunofluorescence of marker proteins. The dual-luciferase reporter and chromatin immunoprecipitation assays were employed to observe the direct transcriptional induction of ROR1 by Twist. A lung metastasis model was used to study the pro-metastatic role of Twist and ROR1 by injecting MDA-MB-231 cells into tail vein of nude mice. Bio-informatics analysis was utilized to measure the metastasis-free survival of breast cancer patients. Results: Twist protein was proved to directly activate the transcription of ROR1 gene, a receptor of Wnt5a in non-canonical WNT signaling pathway. Silencing of ROR1 inhibited EMT process, cell migration, invasion, and cancer metastasis of basal-like breast cancer (BLBC) cells. Knockdown of ROR1 also ameliorated the pro-metastatic effect of Twist. Furthermore, analyses of clinical specimens indicated that high expression of both ROR1 and Twist tightly correlates with poor metastasis-free survival of breast cancer patients. Conclusion: ROR1 is a targeted gene of Twist. Twist/ROR1 signaling is critical for invasion and metastasis of BLBC cells
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