278 research outputs found

    Estimating and mapping the soil total nitrogen contents in black soil region using hyperspectral images towards environmental heterogeneity

    Get PDF
    Introduction: Fast and accurate estimation and spatial mapping of soil total nitrogen (TN) content is important for the development of modern precision agriculture, such as soil fertility monitoring and land reclamation decision-making. Hyperspectral remote sensing has been demonstrated to be an accurate real-time technique for rapid estimation and mapping of soil TN content.Methods: To solve the problem of poor accuracy and generalization of estimation models caused by soil environmental heterogeneity in estimating and mapping soil TN content using hyperspectral images, 502 soil samples were collected from a typical black soil area in Yushu City, Jilin Province, China, as a test area, and three sample grouping strategies were established by soil environmental variables (soil type, thickness of the black soil layer, and topographic factors), and Pearson correlation coefficient and competitive adaptive reweighted sampling algorithm were used to determine the TN characteristic bands of each sample set under different strategies. Based on the data characteristics of the sub-sample set, the local regression estimation model based on sample grouping was constructed using the CatBoost algorithm, and the estimation and distribution mapping of soil TN content was carried out.Results and Discussion: The results showed that after dividing the samples according to the differences in soil environmental factors, the characteristic information of the samples is more targeted, with more abundant numbers and distribution ranges of TN characteristic bands. Compared to the global regression estimation with all samples, the local regression based on the grouping of soil environment differences showed improved accuracy, with the local regression estimation model constructed with the ST-G strategy exhibiting the highest estimation accuracy (Rp2 = 0.839). The results can provide a reference for large-area soil properties mapping, and technical support for soil quality digitization and precision fertilization

    Dual-polarization huge photonic spin Hall shift and deep-subwavelength sensing based on topological singularities in one-dimensional photonic crystals

    Full text link
    Although several efforts have been taken to enhance the photonic spin Hall shift in deep-subwavelength region, according to effective medium theory, the fundamental confliction between near-zero reflection coefficient and near-zero incident angle still hinders the further application. Here, we reveal a fundamental breakdown of effective medium theory due to the existing of topological singularity in deep-subwavelength region in one-dimensional photonic crystals. We find that near the topological singularity, huge photonic spin Hall shift can be achieved for s-polarization and p-polarization. At the topological singularity, the reflected filed is split as dipole-like distribution with zero photonic spin Hall shift for both-polarizations, which is resulted from the interfere of the spin-maintained normal light and spin-flipped abnormal light. Based on the theoretical research, dual-polarizations thickness and dielectric constant sensing devices can be designed in deep-subwavelength region. Further more, by applying more complicated layered structure, multi-channels dual-polarizations detection and broadband dual-polarizations huge spin Hall shift platform can be designed. This work paves the way to exploring the topological properties and polarization control of photonic crystals and provides a prospective method for the design of multi-channels sensitive detection spin optical devices

    Identifying the Risky SNP of Osteoporosis with ID3-PEP Decision Tree Algorithm

    Get PDF
    In the past 20 years, much progress has been made on the genetic analysis of osteoporosis. A number of genes and SNPs associated with osteoporosis have been found through GWAS method. In this paper, we intend to identify the suspected risky SNPs of osteoporosis with computational methods based on the known osteoporosis GWAS-associated SNPs. The process includes two steps. Firstly, we decided whether the genes associated with the suspected risky SNPs are associated with osteoporosis by using random walk algorithm on the PPI network of osteoporosis GWAS-associated genes and the genes associated with the suspected risky SNPs. In order to solve the overfitting problem in ID3 decision tree algorithm, we then classified the SNPs with positive results based on their features of position and function through a simplified classification decision tree which was constructed by ID3 decision tree algorithm with PEP (Pessimistic-Error Pruning). We verified the accuracy of the identification framework with the data set of GWAS-associated SNPs, and the result shows that this method is feasible. It provides a more convenient way to identify the suspected risky SNPs associated with osteoporosis

    Experimental study on treatment of Fe2+ and Mn2+ in AMD with lignite combined with Pseudomonas aeruginosa immobilized SRB particles

    Get PDF
    Sulfate-Reducing Bacteria (SRB) are easily inhibited by high concentrations of heavy metals, low pH as well as the need to add carbon source materials, the microbial immobilization technology was adopted, with SRB, Pseudomonas aeruginosa and lignite as the main immobilization substrates, to prepare lignite and Pseudomonas aeruginosa immobilized SRB particles (L-P-SRB) and the removal effect of L-P-SRB on Fe2+, Mn2+ and SO4 2− in acid mine wastewater (AMD) was investigated. Based on the reduction kinetics and adsorption kinetics, the mechanism of AMD treatment by L-P-SRB was revealed by means of scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FT-IR), and the mechanism of L-P-SRB treating AMD was revealed. At the same time, the repair effect of low temperature treatment of L-P-SRB on AMD is explored, which provides a certain basis for the treatment of AMD in mining areas under the condition of low temperature. The results show that the removal rates of Fe2+ and Mn2+ by L-P-SRB are 91% and 79% respectively, and the process of adsorption of Fe2+ and Mn2+ conforms to the pseudo-first-order kinetics; the removal rate of SO4 2− reaches 91.28% and 81.94% respectively, and the process of reducing SO4 2− is in accordance with the first-order kinetics. Compared with Fe2+, Mn2+ has a certain inhibitory effect on the activity of L-P-SRB. L-P-SRB can remove Fe2+, Mn2+ and SO4 2− in wastewater at one time, which well solves the problem that lignite can only adsorb heavy metal ions and SRB needs to add carbon source. Low temperature cold storage treatment will not inhibit the activity of L-P-SRB, which provides a basis for one-time preparation and multiple use. According to the detection of SEM and FT-IR, pseudomonas aeruginosa plays a priority role in the treatment of wastewater by L-P-SRB, destroying the structure of lignite, destroying some functional groups, breaking the C—C bond, C=O bond and side chain of cycloalkanes, alkanes and olefins in lignite, producing a large number of small molecule organic substances, increasing the specific surface area of particles, and improving the adsorption capacity of particles. At the same time, lignite provides a carrier and a large number of carbon sources for the reduction of SO4 2− by SRB, which promotes the growth of SRB and improves the treatment effect of AMD

    MicroRNAs located in the Hox gene clusters are implicated in huntington\u27s disease pathogenesis

    Get PDF
    Transcriptional dysregulation has long been recognized as central to the pathogenesis of Huntington\u27s disease (HD). MicroRNAs (miRNAs) represent a major system of post-transcriptional regulation, by either preventing translational initiation or by targeting transcripts for storage or for degradation. Using next-generation miRNA sequencing in prefrontal cortex (Brodmann Area 9) of twelve HD and nine controls, we identified five miRNAs (miR-10b-5p, miR-196a-5p, miR-196b-5p, miR-615-3p and miR-1247-5p) up-regulated in HD at genome-wide significance (FDR q-value \u3c 0.05). Three of these, miR-196a-5p, miR-196b-5p and miR-615-3p, were expressed at near zero levels in control brains. Expression was verified for all five miRNAs using reverse transcription quantitative PCR and all but miR-1247-5p were replicated in an independent sample (8HD/8C). Ectopic miR-10b-5p expression in PC12 HTT-Q73 cells increased survival by MTT assay and cell viability staining suggesting increased expression may be a protective response. All of the miRNAs but miR-1247-5p are located in intergenic regions of Hox clusters. Total mRNA sequencing in the same samples identified fifteen of 55 genes within the Hox cluster gene regions as differentially expressed in HD, and the Hox genes immediately adjacent to the four Hox cluster miRNAs as up-regulated. Pathway analysis of mRNA targets of these miRNAs implicated functions for neuronal differentiation, neurite outgrowth, cell death and survival. In regression models among the HD brains, huntingtin CAG repeat size, onset age and age at death were independently found to be inversely related to miR-10b-5p levels. CAG repeat size and onset age were independently inversely related to miR-196a-5p, onset age was inversely related to miR-196b-5p and age at death was inversely related to miR-615-3p expression. These results suggest these Hox-related miRNAs may be involved in neuroprotective response in HD. Recently, miRNAs have shown promise as biomarkers for human diseases and given their relationship to disease expression, these miRNAs are biomarker candidates in HD

    Different molecular characteristics and antimicrobial resistance profiles of Clostridium difficile in the Asia-Pacific region

    Get PDF
    Molecular epidemiology of Clostridium difficile infection (CDI) has been extensively studied in North America and Europe; however, limited data on CDI are available in the Asia-Pacific region. A multicentre retrospective study was conducted in this region. C. difficile isolates were subjected to multilocus sequence typing (ST) and antimicrobial susceptibility testing. Totally, 394 isolates were collected from Hangzhou, Hong Kong, China; Busan, South Korea; Fukuoka, Japan; Singapore; Perth, Sydney, Australia; New York, the United States. C. difficile isolates included 337 toxin A-positive/B-positive/binary toxin-negative (A+B+CDT-), 48 A-B+CDT-, and nine A+B+CDT+. Distribution of dominant STs varied geographically with ST17 in Fukuoka (18.6%), Busan (56.0%), ST2 in Sydney (20.4%), Perth (25.8%). The antimicrobial resistance patterns were significantly different among the eight sites (χ2 = 325.64, p \u3c 0.001). Five major clonal complexes correlated with unique antimicrobial resistances. Healthcare-associated (HA) CDI was mainly from older patients with more frequent antimicrobial use and higher A-B+ positive rates. Higher resistance to gatifloxacin, tetracycline, and erythromycin were observed in HA-CDI patients (χ2 = 4.76-7.89, p = 0.005-0.029). In conclusion, multiple C. difficile genotypes with varied antimicrobial resistance patterns have been circulating in the Asia-Pacific region. A-B+ isolates from older patients with prior antimicrobial use were correlated with HA-CDI

    Proteomic analysis of differential proteins in pancreatic carcinomas: Effects of MBD1 knock-down by stable RNA interference

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Methyl-CpG binding domain protein 1 (MBD1), a suppressor of gene transcription, may be involved in inactivation of tumor suppressor genes during tumorigenesis. Over-expression of MBD1 has been reported in human pancreatic carcinomas.</p> <p>Methods</p> <p>In this study, we established a MBD1-knock-down pancreatic cancer cell line (BxPC-3) using stable RNA interference, to compare the proteomic changes between control and MBD1-knock-down cells using two-dimensional gel electrophoresis and mass spectrometry.</p> <p>Results</p> <p>We identified five proteins that were up-regulated and nine proteins that were down-regulated. Most of the identified proteins are involved in tumorigenesis, some are prognostic biomarkers for human malignant tumors.</p> <p>Conclusion</p> <p>Our data suggest that these differential proteins may be associated with the function of MBD1, and provide some insight into the functional mechanism of MBD1 in the development of pancreatic cancer.</p
    • …
    corecore