Chaos UWB Radar for Through-the-Wall Imaging Venkatasubramanian, V.; Leung, H.; Xiaoxiang Liu
IEEE transactions on image processing,
06/2009, Letnik:
18, Številka:
6
Journal Article
Recenzirano
In this paper, we propose to apply a novel chaos-based ultra-wide band (UWB) radar for through-the-wall imaging. The proposed chaos modulation offers superior resolution compared to conventional UWB ...radars when applied for through-the-wall imaging. A noncoherent receiver is designed based on expectation maximization (EM) algorithm. The theoretical detection performance is derived for through-the-wall detection in the presence and absence of room reverberations as a function of dielectric properties of walls, targets, and their geometry illustrating the robustness of the proposed modulation against room reverberations. The resolution of the proposed modulation is analyzed theoretically and verified through simulations for different wall materials. Numerical electromagnetic simulations using finite difference time domain (FDTD) method are performed to confirm the obtained theoretical results. From the theoretical and simulation analysis, we find that the proposed chaos-based pulse amplitude modulated ultra-wide band (CPAM-UWB) radar has better detection performance, penetrating ability and imaging performance compared to other conventional through-the-wall imaging radars.
Although mariculture contributes significantly to regional/local economic development, it also promotes environmental degradation. Therefore, it is essential to understand mariculture dynamics before ...taking adaptive measures to deal with it. In the present study, a framework that integrates the Google Earth Engine (GEE) based methods and GeoDetector software was developed to identify patterns and drivers of mariculture dynamics. This framework was then applied to Zhao’an Bay, which is an intensive aquaculture bay in Coastal China, based on Landsat 8 OLI (2013–2022) and Sentinel-2 (December 2015–May 2022) data. The results show that the GEE-based method produces acceptable classification accuracy. The overall accuracy values for the interpretation are >85%, where the kappa coefficients are >0.9 for all years, excluding 2015 (0.83). Mariculture increased in the study area from 2013 to 2022, and this is characterised by distinct spatiotemporal variations. Cage mariculture is primarily concentrated around islands, whereas raft mariculture is dominant in bay areas, and pond and mudflat mariculture types are mostly in nearshore areas. The growth of mariculture in Zhao’an Bay is attributed to a combination of geographic and human factors. The initial area associated with mariculture in a grid significantly impacted the expansion of the raft, cage, and mudflat mariculture. The distance to an island, spatial proximity to similar types of mariculture and types of mariculture are the main drivers of change in mariculture. Human activities greatly contribute to the dynamics of mudflat mariculture; regulation regarding the clearing of waterways directly impacts the dynamics of mariculture. The present study demonstrates that the proposed framework facilitates the effective monitoring of the mariculture dynamics and identification of driving factors. These findings can be exploited for the local planning and management of mariculture in similar coastal bays.
Upper Triassic tight sandstones in Ordos Basin are typical tight oil reservoirs in China. Using a combination of thin sections, SEM, BSE, EDS and mercury injection, 48 sandstone core samples from 17 ...wells in the study area were collected to investigate the diagenetic heterogeneity, pore-throat characteristics and their correlations with reservoir quality.
Five diagenetic types were identified according to their specific diagenetic evolution pathways. Type A sandstones are characterized by abundant authigenic chlorite rims, rare quartz cement and high porosity. Type B sandstones underwent moderate compaction, moderate dissolution and moderate cementation. Samples from Type C are characterized by intense dissolution and large amounts of carbonate cements, they can be subdivided into two categories according to if pore throats in larger size were still reserved (Type C2) or not (Type C1) after late-stage cementation. Type D sandstones underwent intense compaction, moderate dissolution and minor carbonate cementation. Type E sandstones are characterized by the most intense compaction.
Depending on the pore-throat size distributions from MICP analysis, three sandstone types with their own specific pore-throat characteristics were identified. Type Ⅰ sandstones generally contain a certain amount of mesopores (including a few macropores) and pore spaces are dominant intergranular pores, intragranular pores and even oversized pores. These sandstones generally correspond to Type A, B, C2 and D sandstones and thus represent good-quality reservoir. Type Ⅱ sandstones usually contain dominant transitional pores (77% in average) and their pore systems mianly consist of clay intercrystal microporosity and a few isolated intergranular or intragranular pores. Type Ⅲ sandstones are representative by relatively abundant micropores (17.7% in average) and pore spaces are dominant clay intercrystal microporosity. Type Ⅱ and Type Ⅲ pore structures generally correspond to Type C1 and E and thus represent poor-quality reservoir. This study gives insights into the link between different diagenetic features, pore structures and their impact on reservoir quality and this will be helpful for reservoir prediction.
•Diagenesis was mainly governed by composition, depositional environment and fluid flow.•Five diagenetic types were identified according to different diagenetic evolution pathways.•Pore-throat characteristics were investigated by petrographic observations and MICP test.•The diagenetic types are associated with pore-throat types and further with petrophysical properties.
Microbial contamination is considered the main cause of food spoilage.
is a typical spoilage bacterium contributing to a large extent to the spoilage process of proteinaceous foods. RpoS is known as ...an alternative sigma factor controlling stress resistance and virulence in many pathogens. Our previous work revealed that RpoS contributes to the spoilage activities of
.
by regulating resistance to different stress conditions, extracellular acylated homoserine lactone (AHL) levels, extracellular protease and total volatile basic nitrogen (TVB-N) production. However, RpoS-dependent genes in
.
remained undefined. RNA-seq transcriptomics analysis combined with quantitative proteomics analysis based on multiplexed isobaric tandem mass tag (TMT) labeling was performed in the
.
wild-type strain UK4 and its derivative carrying an
mutation. A total of 375 differentially expressed coding sequences (DECs) and 212 differentially expressed proteins (DEPs) were identified. The DECs were further verified by qRT-PCR. The combined transcriptome and proteome analyses revealed the involvement of this regulator in several cellular processes, mainly including polysaccharide metabolism, intracellular secretion, extracellular structures, cell wall biogenesis, stress responses, and amino acid and biogenic amine metabolism, which may contribute to the biofilm formation, stress resistance, and spoilage activities of
.
. Moreover, we indeed observed that RpoS contributed to the production of the macrocolony biofilm's matrix. Our results provide insights into the regulatory network of RpoS and expand the knowledge about the role of RpoS in the functioning of
in food spoilage.
Abstract
Stitched fluorescence microscope images inevitably exist in various types of stripes or artifacts caused by uncertain factors such as optical devices or specimens, which severely affects the ...image quality and downstream quantitative analysis. Here, we present a deep learning-based Stripe Self-Correction method, so-called SSCOR. Specifically, we propose a proximity sampling scheme and adversarial reciprocal self-training paradigm that enable SSCOR to utilize stripe-free patches sampled from the stitched microscope image itself to correct their adjacent stripe patches. Comparing to off-the-shelf approaches, SSCOR can not only adaptively correct non-uniform, oblique, and grid stripes, but also remove scanning, bubble, and out-of-focus artifacts, achieving the state-of-the-art performance across different imaging conditions and modalities. Moreover, SSCOR does not require any physical parameter estimation, patch-wise manual annotation, or raw stitched information in the correction process. This provides an intelligent prior-free image restoration solution for microscopists or even microscope companies, thus ensuring more precise biomedical applications for researchers.
Currently, no vaccine to prevent hepatitis C virus (HCV) infection is available. A major challenge in developing an HCV vaccine is the high diversity of HCV sequences. The purpose of immunization ...with viral glycoproteins is to induce a potent and long-lasting cellular and humoral immune response. However, this strategy only achieves limited protection, and antigen selection plays a crucial role in vaccine design. In this study, we investigated the humoral immune responses induced by intraperitoneal injection of keyhole limpet hemocyanin conjugated with 4 highly conserved peptides, including amino acids aa317-325 from E1 and aa418-429, aa502-518, and aa685-693 from E2, or 3 peptides from hypervariable region 1 (HVR1) of E2, including the N terminus of HVR1 (N-HVR1, aa384-396), C terminus of HVR1 (C-HVR1, aa397-410), and HVR1 in BALB/c mice. The neutralizing activity against HCV genotypes 1-6 was assessed using the cell culture HCV (HCVcc) system. The results showed that the 4 conserved peptides efficiently induced antibodies with potent neutralizing activity against 3 or 4 genotypes. Antibodies induced by aa685-693 conferred potent protection (>50%) against genotypes 2, 4, and 5. Peptide N-HVR1 elicited antibodies with the most potent neutralization activities against 3 HCV genotypes: TNcc(1a), S52(3a), and ED43(4a). These findings suggested that peptides within HCV glycoproteins could serve as potent immunogens for vaccine design and development.
Epigallocatechin gallate (EGCG) is a main constituent of green tea polyphenols that are widely used as food preservatives and are considered to be safe for consumption. However, the underlying ...antimicrobial mechanism of EGCG and the bacterial response to EGCG are not clearly understood. In the present study, a genome-wide transcriptional analysis of a typical spoilage bacterium, Pseudomonas fluorescens that responded to EGCG was performed using RNA-seq technology. A total of 26,365,414 and 23,287,092 clean reads were generated from P. fluorescens treated with or without 1 mM EGCG and the clean reads were aligned to the reference genome. Differential expression analysis revealed 291 upregulated genes and 134 downregulated genes and the differentially expressed genes (DEGs) were verified using RT-qPCR. Most of the DGEs involved in iron uptake, antioxidation, DNA repair, efflux system, cell envelope and cell-surface component synthesis were significantly upregulated by EGCG treatment, while most genes associated with energy production were downregulated. These transcriptomic changes are likely to be adaptive responses of P. fluorescens to iron limitation and oxidative stress, as well as DNA and envelope damage caused by EGCG. The expression of specific genes encoding the extra-cytoplasmic function sigma factor (PvdS, RpoE and AlgU) and the two-component sensor histidine kinase (BaeS and RpfG) were markedly changed by EGCG treatment, which may play important roles in regulating the stress responses of P. fluorescens to EGCG. The present data provides important insights into the molecular action of EGCG and the possible cross-resistance mediated by EGCG on P. fluorescens, which may ultimately contribute to the optimal application of green tea polyphenols in food preservation.
Pseudomonas fluorescens
is a typical spoiler of proteinaceous foods, and it is characterized by high spoilage activity. The sigma factor RpoN is a well-known regulator controlling nitrogen ...assimilation and virulence in many pathogens. However, its exact role in regulating the spoilage caused by
P
.
fluorescens
is unknown. Here, an in-frame deletion mutation of
rpoN
was constructed to investigate its global regulatory function through phenotypic and RNA-seq analysis. The results of phenotypic assays showed that the
rpoN
mutant was deficient in swimming motility, biofilm formation, and resistance to heat and nine antibiotics, while the mutant increased the resistance to H
2
O
2
. Moreover, the
rpoN
mutant markedly reduced extracellular protease and total volatile basic nitrogen (TVB-N) production in sterilized fish juice at 4°C; meanwhile, the juice with the
rpoN
mutant showed significantly higher sensory scores than that with the wild-type strain. To identify RpoN-controlled genes, RNA-seq-dependent transcriptomics analysis of the wild-type strain and the
rpoN
mutant was performed. A total of 1224 genes were significantly downregulated, and 474 genes were significantly upregulated by at least two folds at the RNA level in the
rpoN
mutant compared with the wild-type strain, revealing the involvement of RpoN in several cellular processes, mainly flagellar mobility, adhesion, polysaccharide metabolism, resistance, and amino acid transport and metabolism; this may contribute to the swimming motility, biofilm formation, stress and antibiotic resistance, and spoilage activities of
P
.
fluorescens
. Our results provide insights into the regulatory role of RpoN of
P
.
fluorescens
in food spoilage, which can be valuable to ensure food quality and safety.
Tight sandstone oil reservoirs have received increasing attention in petroleum exploration and exploitation. Previous research concerning tight oil reservoirs has predominantly focused on marine ...basins. However, in China, tight oil reservoirs are mostly distributed in lacustrine basins. Taking the tight oil sandstones of the Yanchang Formation Chang 7 oil reservoir interval (the Chang 7 for short) in the Ordos Basin as an example, five factors are identified that control their formation and occurrence. Firstly, three episodes of oil charging took place during the Early Cretaceous, which were 142–139 Ma, 128–122 Ma and 114–106 Ma, respectively. Continuous generation and episodic expulsion led to multiple episodes of oil accumulation. Secondly, widely distributed source rocks (TOC > 1.0%) provide hydrocarbons to the Chang 7. The distribution of tight oil was controlled by the outer boundary of the source rock distribution, while the transition areas between generation (expulsion) centers were the accumulation and enrichment zones in the Chang 7. Thirdly, with the favorable conditions for retained hydrocarbons, massive continuous tight reservoir beds (average porosity = 7.6% and average permeability = 0.15 mD) developed in the Chang 7 capable of forming large-scale successive tight oil reservoirs. Fourthly, different source-reservoir assemblages have different expulsion patterns and amounts, which led to different charging degrees and sizes of tight oil accumulations. Type III (source-reservoir interbeds) will be the most favorable target for exploration and exploitation in the Chang 7, Ordos Basin. Finally, under the driving mechanism of non-buoyancy migration and accumulation, pressure differences between source and reservoir rocks (PDBSR) serve as the primary expulsion and migration force for crude oil during the main accumulation periods in the Chang 7.
•Three charging episodes (142–139 Ma, 128–122 Ma and 114–106 Ma) were identified.•Source rocks control the distribution of tight oil reservoirs.•Tight reservoir beds form the continuous “retained-accumulation”.•Different source-reservoir assemblages lead to different charging degrees.•PDBSR provided the main expulsion and charging force for crude oil.
•2-D PAGE/MS is suited for studies on degradation patterns of protein.•TP is effective in preservation of large yellow croaker fillets during storage.•TP has an effective impact on muscle proteins ...integrity post-mortem.
Tea polyphenols (TP) are known to be important for the post-mortem deterioration of fish muscle and can enhance food quality. To shed light on the influence of TP on the status of large yellow croaker muscle proteins, control and treated fillets (0.1% TP, 0.2% TP and 0.3% TP, w/v) were analysed periodically for myofibrillar protein functional properties (Ca2+-ATPase activity, surface hydrophobicity, total sulfhydryl content, emulsion stability index and rheological behaviour). Degradation of the myofibrillar protein myosin could be clearly observed; several proteins were also observed to vary in abundance following post-mortem storage for 25days. The present study offers new evidence that TP have an effective impact on muscle protein integrity post-mortem.
PDF
