190 research outputs found

    Reliability analysis of the internet of things using Space Fault Network

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    The Internet of Things (IoT) is a network topology structure based on the interconnection of many nodes. It realizes the basic functions of IoT through the transmission of information, data, and energy between the nodes. To study the reliability of Internet of Things Network Topology (IoTNT) structure, we must abstract IoT as network topology and study the reliability of the network itself from the topology structure. This paper attempts to apply the Space Fault Network (SFN) to the study the reliability of IoTNT. To achieve this goal, the nodes and edges of IoTNT are equivalent to events and connections of SFN respectively. A structure analysis method based on SFN is proposed and used to study the reliability of IoTNT. At the same time, the influence of possible logical relationship between nodes on the reliability of IoTNT is studied. According to the SFN structure representation methods (SFNSRMs), considering different network structures and induced modes, the analysis methods and calculation methods of the evolution process of target event are given. An example is given to illustrate the analysis and calculation process. The research provides the new methods for the reliability study of IoT and the development of SFN

    Predicting and understanding spatio-temporal dynamics of species recovery : implications for Asian crested ibis Nipponia nippon conservation in China

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    Acknowledgements This work was supported by the National Natural Science Foundation of China (No. 31372218) and cofunded by the China Scholarship Council (CSC) and the ITC Research Fund, Enschede, the Netherlands. We thank Shaanxi Hanzhong Crested Ibis National Nature Reserve for sharing the data of nest site locations. We are grateful to Brendan Wintle, Justin Travis and two anonymous reviewers for helpful comments on a previous version of the manuscript.Peer reviewedPublisher PD

    Molecular Determinants of HIV-1 Subtype C Coreceptor Transition from R5 to R5X4

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    The molecular mechanism(s) underlying transition from CCR5 to CXCR4 usage of subtype C viruses remain largely unknown. We previously identified a subtype C HIV-1 infected child whose virus demonstrated CXCR4 usage along with CCR5 upon longitudinal follow-up. Here we delineated the molecular determinants of Env involved in expanded coreceptor usage. Residue changes in three positions of Env V3 domain are critical for the dual-tropic phenotype. These include: substitution of arginine at position 11, MG or LG insertion between positions 13 and 14, and substitution of threonine at the position immediately downstream of the GPGQ crown. Introducing these mutations into V3 region of another R5 virus also conferred dual tropism. Molecular modeling of V3 revealed a possible structural basis for the dual-tropic phenotype. Determining what defines a subtype C X4 virus will lead to a better understanding of subtype C HIV-1 pathogenesis, and will provide important information relevant to anti-retroviral therapy

    Evolutionary characteristics and genetic transmission patterns of predominant HIV-1 subtypes among men who have sex with men in China.

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    OBJECTIVES: Men who have sex with men (MSM) represent one of the major risk groups for HIV-1 infection in China, and the predominant subtypes among this population has changed over the last two decades. The objective of this study was to determine the evolutionary characteristics and transmission patterns of the dominant HIV-1 strains in the Chinese MSM population. METHODS: A total of 4980 published HIV-1 pol gene sequences from MSM in China were retrieved and comprehensive evolutionary and transmission analyses were then conducted. Bayesian coalescent-based methods and selection pressure analyses were used to reconstruct the time-scale and demographic history and to estimate other evolutionary parameters. Transmission patterns were characterized using network analyses. RESULTS: There were 2546 (51.12%) CRF01_AE, 1263 (25.36%) CRF07_BC, and 623 (12.51%) subtype B, accounting for 88.99% of the total sequences. From 2000 to 2016, the prevalence of CRF01_AE was stable, comprising nearly half of all sequences over time (58.33-45.38%, p=0.071). CRF07_BC increased slightly from 13.3% to 22.49% (p<0.001), while subtype B decreased dramatically from 41.67% to 9.04% (p<0.001). Demographic reconstruction showed that the greatest expansion of the HIV epidemic occurred between 1999 and 2005. CRF01_AE had a higher estimated evolutionary rate (2.97×10-3 substitutions/site/year) and exhibited more sites under positive selection (25/351 codons) compared to the other subtypes. Network analyses showed that CRF07_BC (68.29%, 84/123) had a higher proportion of cross-region networks than CRF01_AE (49.1%, 174/354) and subtype B (36.46%, 35/96) (p<0.001). CONCLUSIONS: The predominant subtypes of HIV-1 in Chinese MSM have different evolutionary characteristics and transmission patterns, which poses a significant challenge to HIV treatment and disease prevention
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