False Data Filtering Strategy in Wireless Sensor Network Based on Neighbor Node Monitoring

The injection attack of false data is a common attack form in wireless sensor network. This attack form achieves the purpose of consuming limited network resources and severely threatens the safety of wireless sensor network through consistent sending false data. This paper proposes a type of false data filtering strategy based on neighbor node monitoring. The idea of this strategy is to enable each node to store the neighbor node's information within the two-hop range. In the meantime, the data package determines whether the upstream node is original node or data forwarding intermediate node through whether ACK package is remitted by the upstream node to avoid the impersonation of wireless sensor network node by malicious node. The false data package of malicious node will be filtered within one hop. The simulation experiment verifies the filtering performance and anti-capture performance of this strategy, thus guaranteeing the safety of wireless sensor network

Evaluating the Effectiveness of Conservation on Mangroves: A Remote Sensing-Based Comparison for Two Adjacent Protected Areas in Shenzhen and Hong Kong, China

Mangroves are ecologically important ecosystems and globally protected. The purpose of this study was to evaluate the effectiveness of mangrove conservation efforts in two adjacent protected areas in China that were under the management policies of the Ramsar Convention (Mai Po Marshes Nature Reserve (MPMNR), Hong Kong) and China’s National Nature Reserve System (Futian Mangrove National Nature Reserve (FMNNR), Shenzhen). To achieve this goal, eleven Landsat images were chosen and classified, areal extent and landscape metrics were then calculated. The results showed that: from 1973–2015, the areal extent of mangroves in both reserves increased, but the net change for the MPMNR (281.43 hm2) was much higher than those of the FMNNR (101.97 hm2). In general, the area-weighted centroid of the mangroves in FMNNR moved seaward by approximately 120 m, whereas in the MPMNR, the centroid moved seaward even farther (410 m). Although both reserves saw increased integrality and connectivity of the mangrove patches, the patches in the MPMNR always had higher integrality than those in the FMNNR. We concluded that the mangroves in the MPMNR were more effectively protected than those in the FMNNR. This study may provide assistance to the formulation of generally accepted criteria for remote sensing-based evaluation of conservation effectiveness, and may facilitate the development of appropriate mangrove forest conservation and management strategies in other counties

Cells and Fugu Response to Capsid of BFNNV Genotype

The nervous necrosis virus (NNV) of the BFNNV genotype is the causative agent of viral encephalopathy and retinopathy (VER) in cold water fishes. Similar to the RGNNV genotype, BFNNV is also considered a highly destructive virus. In the present study, the RNA2 of the BFNNV genotype was modified and expressed in the EPC cell line. The subcellular localization results showed that the capsid and N-terminal (1–414) were located in the nucleus, while the C-terminal (415–1014) of the capsid was located in the cytoplasm. Meanwhile, cell mortality obviously increased after expression of the capsid in EPC. EPC cells were transfected with pEGFP-CP and sampled at 12 h, 24 h and 48 h for transcriptome sequencing. There are 254, 2997 and 229 up-regulated genes and 387, 1611, and 649 down-regulated genes post-transfection, respectively. The ubiquitin-activating enzyme and ubiquitin-conjugating enzyme were up-regulated in the DEGs, indicating that cell death evoked by capsid transfection may be related to ubiquitination. The qPCR results showed that heat stock protein 70 (HSP70) is extremely up-regulated after expression of BFNNV capsid in EPC, and N-terminal is the key region to evoke the high expression. For further study, the immunoregulation of the capsid in fish pcDNA-3.1-CP was constructed and injected into the Takifugu rubripes muscle. pcDNA-3.1-CP can be detected in gills, muscle and head kidney, and lasted for more than 70 d post-injection. The transcripts of IgM and interferon inducible gene Mx were up-regulated after being immunized in different tissues, and immune factors, such as IFN-γ and C3, were also up-regulated in serum, while C4 was down-regulated one week after injection. It was suggested that pcDNA-3.1-CP can be a potential DNA vaccine in stimulating the immune system of T. rubripes; however, NNV challenge needs to be conducted in the following experiments

Acoustic Emission Multi-Parameter Analysis of Dry and Saturated Sandstone with Cracks under Uniaxial Compression

In order to study the mechanics and acoustic emission (AE) characteristics of fractured rock under water-rock interaction, dried and saturated sandstone samples with prefabricated double parallel cracks were prepared. Then, uniaxial compression experiments were performed to obtain their AE signals and crack propagation images. The results show that water reduces the strength and fracture toughness of fractured sandstone and enhances plasticity. After saturation, the samples start to crack earlier; the cracks grow slowly; the failure mode is transformed from shear failure along the prefabricated cracks to combined shear and tensile failure; more secondary cracks are produced. The saturated samples release less elastic energy and weaker AE signals in the whole failure process. However, their AE precursor information is more obvious and advanced, and their AE sources are more widely distributed. Compared with dry specimens, the AE frequencies of saturated specimens in the early stage of loading are distributed in a lower frequency domain. Besides, the saturated samples release less complex AE signals which are dominated by small-scale signals with weaker multi-fractal characteristics. After discussion and analysis, it is pointed out that this may be because water makes rock prone to inter-granular fracture rather than trans-granular fracture. The water lubrication also may reduce the amplitude of middle-frequency band signals produced by the friction on the fracture surface. Multi-fractal parameters can provide more abundant precursory information for rock fracture. This is of great significance to the stability of water-bearing fractured rock mass and its monitoring, and is conducive to the safe exploitation of deep energy

Comparative Metabolomic-Based Metabolic Mechanism Hypothesis for Microbial Mixed Cultures Utilizing Cane Molasses Wastewater for Higher 2‑Phenylethanol Production

The mixed microbes coculture method in cane molasses wastewater (CMW) was adopted to produce 2-phenylethanol (2-PE). Comparative metabolomics combined with multivariate statistical analysis was performed to profile the differences of overall intracellular metabolites concentration for the mixed microbes cocultured under two different fermentation conditions with low and high 2-PE production. In total 102 intracellular metabolites were identified, and 17 of them involved in six pathways were responsible for 2-PE biosynthesis. After further analysis of metabolites and verification by feeding experiment, an overall metabolic mechanism hypothesis for the microbial mixed cultures (MMC) utilizing CMW for higher 2-PE production was presented. The results demonstrated that the branches of intracellular pyruvate metabolic flux, as well as the flux of phenylalanine, tyrosine, tryptophan, glutamate, proline, leucine, threonine, and oleic acid, were closely related to 2-PE production and cell growth, which provided theoretical guidance for domestication and selection of species as well as medium optimization for MMC metabolizing CMW to enhance 2-PE yield