76 research outputs found

    LSSTCS- A Social-Based DTN Routing in Cooperative Vehicular Sensor Networks

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    As a cooperative information system, vehicles in Vehicular Sensor Networks delivery messages based on collaboration. Due to the high speed of vehicles, the topology of the network is highly dynamic, and the network may be disconnected frequently. So how to transfer large files in such network is worth considering. In case that the encountering nodes which never meet before flood messages blindly to cause tremendous network overhead. We address this challenge by introducing the Encounter Utility Rank Router(EURR) based on social metrics. EURR includes three cases: Utility Replication Strategy, Lifetime Replication Strategy and SocialRank Replication Strategy. The Lifetime Replication is promising complement to Utility Replication. It enhances the delivery ratio by relaying the copy via the remaining lifetime. Considering network overhead, the SocialRank Replication replicates a copy according to the SocialRank when two communicating nodes do not meet before. The routing mechanism explores the utility of history encounter information and social opportunistic forwarding. The results under the scenario show an advantage of the proposed Encounter Utility Rank Router (EURR) over the compared algorithms in terms of delivery ratio, average delivery latency and overhead ratio

    Novel Opportunistic Network Routing Based on Social Rank for Device-to-Device Communication

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    In recent years, there has been dramatic proliferation of research concerned with fifth-generation (5G) mobile communication networks, among which device-to-device (D2D) communication is one of the key technologies. Due to the intermittent connection of nodes, the D2D network topology may be disconnected frequently, which will lead to failure in transmission of large data files. In opportunistic networks, in case of encountering nodes which never meet before a flood message blindly to cause tremendous network overhead, a novel opportunistic network routing protocol based on social rank and intermeeting time (SRIT) is proposed in this paper. An improved utility approach applied in utility replication based on encounter durations and intermeeting time is put forward to enhance the routing efficiency. Meanwhile, in order to select better candidate nodes in the network, a social graph among people is established when they socially relate to each other in social rank replication. The results under the scenario show an advantage of the proposed opportunistic network routing based on social rank and intermeeting time (SRIT) over the compared algorithms in terms of delivery ratio, average delivery latency, and overhead ratio

    Numerical calculation of oil film for ship stern bearing based on matrix method

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    Radial sliding bearings are widely used in ship shafting, its characteristics of lubricating oil film have important influence on the normal operation of the whole shaft system. In this work, the difference equations which is used to calculate the radial sliding bearing oil film features is transformed into matrix equations, the solving process be converted into solving matrix equation, combined with the powerful matrix calculation function of MATLAB, the solution process is simplified. It is not necessary to set the error precision and relaxation factor, so as to avoid the problem that the calculation result is not stable or even not convergent in the process of Successive Over Relaxation(SOR) method, and the calculation precision and stability are improved. The numerical results of matrix calculation method is compared with the result of SOR method, verified the correctness and feasibility of the matrix calculation method. Because the calculation is relatively stable, the matrix calculation method is more suitable for the calculation core of the relative computing software

    Comparative proteomics study on liver mitochondria of primary biliary cirrhosis mouse model

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    BACKGROUND: Primary biliary cirrhosis (PBC) is a liver specific chronic disease with unclear pathogenesis, especially for the early stage molecular events. The mitochondrion is a multi-functional organelle associated with various diseases including PBC. The purpose of this study was to discover the alterations in the mitochondria proteome using an early stage PBC mouse model for revealing the possible pathogenesis mechanisms in the early stages of PBC. METHODS: Mouse model of early stage of PBC was constructed by consecutive administration of poly I:C. Mitochondria of mouse models and controls were purified and comparative proteomics was performed by iTRAQ technology. Then, differentially expressed proteins were validated by western blotting. RESULTS: In total 354 proteins that satisfied the criteria for comparative proteomics study were identified. Of them, nine proteins were downregulated and 20 were up-regulated in liver mitochondria of PBC mouse model. Most differentially expressed proteins are associated with oxidation-reduction and lipid metabolism, and some are involved in the biosynthesis of steroid hormone and primary bile acid. Interestingly, four proteins (HCDH, CPT I, DECR, ECHDC2) involved in the fatty acid beta-oxidation were all upregulated. CONCLUSIONS: iTRAQ is a powerful tool for comparative proteomics study of PBC mouse model and differentially expressed proteins in mitochondria proteome of PBC mouse model provide insights for the pathogenesis mechanism at early stage of PBC

    Different responses of soil element contents and their stoichiometry (C: N: P) to different grazing intensity on the Tibetan Plateau shrublands

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    Potentilla fruticosa, a major alpine shrubland type, is widely distributed across the Tibetan Plateau, and grazing is the most common disturbance in the shrublands of P. fruticosa. However, soil organic carbon (SOC), soil total nitrogen (STN), soil total phosphorus (STP), and their stoichiometry under different grazing intensities were unclear. In our study, we explored SOC, STN, STP, their stoichiometry, and their controlling factors in the grazing disturbance of heavy grazing (HG), moderate grazing (MG), light grazing (LG), and no grazing (NG) conditions in the Tibetan Plateau P. fruticosa shrublands. The grazing intensities were mainly assessed by considering the shrublands’ ground cover, the indicators of the road density, the distance between sampling sites and cowshed or sheep shed, the amounts of cow and sheep dung, and vegetation that had been gnawed and stampeded. Our results indicated that soil physical properties of soil temperature and bulk density have decreasing trends with decreasing grazing intensities from HG to NG. The SOC, STN, STP, and soil C:N and C:P ratios have increasing trends with decreasing grazing intensities from HG to NG, while the changes in soil N:P ratio were relatively stable along grazing intensities. Our results indicated that HG generally had stronger effects on SOC, STN, and soil C:N and C:P ratios than NG, indicating substantial effects of grazing disturbance on biogeochemical cycles of SOC and STN in the shrubland ecosystems. Therefore, for the alpine shrubland of P. fruticosa, the HG should be avoided for sustainable cycling of soil nutrients and the balance of soil nutrient stoichiometry. The grazing types can directly affect plant conditions, and plant conditions can directly affect soil physical and chemical properties and litter standing crops. Finally, soil physicochemical properties and litter standing crop resulting from different grazing intensities directly control SOC, STN, and STP. For the soil stoichiometry, the soil’s physical and chemical properties resulting from different grazing intensities have direct impacts on soil C:P and N:P ratios

    Metagenomic surveillance and comparative genomic analysis of Chlamydia psittaci in patients with pneumonia

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    Chlamydia psittaci, a strictly intracellular bacterium, is an underestimated etiologic agent leading to infections in a broad range of animals and mild illness or pneumonia in humans. In this study, the metagenomes of bronchoalveolar lavage fluids from the patients with pneumonia were sequenced and highly abundant C. psittaci was found. The target-enriched metagenomic reads were recruited to reconstruct draft genomes with more than 99% completeness. Two C. psittaci strains from novel sequence types were detected and these were closely related to the animal-borne isolates derived from the lineages of ST43 and ST28, indicating the zoonotic transmissions of C. psittaci would benefit its prevalence worldwide. Comparative genomic analysis combined with public isolate genomes revealed that the pan-genome of C. psittaci possessed a more stable gene repertoire than those of other extracellular bacteria, with ~90% of the genes per genome being conserved core genes. Furthermore, the evidence for significantly positive selection was identified in 20 virulence-associated gene products, particularly bacterial membrane-embedded proteins and type three secretion machines, which may play important roles in the pathogen-host interactions. This survey uncovered novel strains of C. psittaci causing pneumonia and the evolutionary analysis characterized prominent gene candidates involved in bacterial adaptation to immune pressures. The metagenomic approach is of significance to the surveillance of difficult-to-culture intracellular pathogens and the research into molecular epidemiology and evolutionary biology of C. psittaci

    Large expert-curated database for benchmarking document similarity detection in biomedical literature search

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    Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

    Structural features of gem minerals and identification and evaluation

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    Gem has long been chased because of its cultural and historical significance and beauty, and the identification and evaluation of its structural features have also been paid attention to. Plum blossom jade and emerald were identified and analyzed by means of the conventional detection method, infrared spectroscopy and X-ray powder diffraction analysis. The results showed that plum blossom jade with black and brown background and red, white and brown amygdaloid body spots had a diameter of 1–10 mm, a relative density of 2.69–2.75 g/cm3 and a refractive index of 1.52–1.55, and its minerals contained water molecules, quartz, low albite, anorthoclase and andesite. It was observed that emerald was green, greasy, glassy, transparent, with a relative density of 2.66–2.78 g/cm3 and 1.58 refractive index, and its minerals contained water molecules; there were two kinds of arrangement in crystal channels. The main mineral component of emerald was beryl, and its purity was high

    Numerical calculation of oil film for ship stern bearing based on matrix method

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    Radial sliding bearings are widely used in ship shafting, its characteristics of lubricating oil film have important influence on the normal operation of the whole shaft system. In this work, the difference equations which is used to calculate the radial sliding bearing oil film features is transformed into matrix equations, the solving process be converted into solving matrix equation, combined with the powerful matrix calculation function of MATLAB, the solution process is simplified. It is not necessary to set the error precision and relaxation factor, so as to avoid the problem that the calculation result is not stable or even not convergent in the process of Successive Over Relaxation(SOR) method, and the calculation precision and stability are improved. The numerical results of matrix calculation method is compared with the result of SOR method, verified the correctness and feasibility of the matrix calculation method. Because the calculation is relatively stable, the matrix calculation method is more suitable for the calculation core of the relative computing software
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