In this paper, a multi-image encryption scheme based on compressed sensing (CS) and deep learning in the optical gyrator domain is proposed. Firstly, multiple plaintext images are compressed by CS to ...obtain multiple measurements, and then the pixels of each measurement are scrambled by using a chaotic system. Secondly, the scrambled measurements are combined into a matrix and diffused by XOR operation with a chaotic matrix. Finally, the diffused matrix is encoded with a random phase and an optical gyrator transform to obtain a complex-valued matrix, and the amplitude of the complex-valued matrix is taken as the ciphertext. In decrypt, plaintext images are reconstructed from the CS measurements by a neural network, which achieves high reconstruction speed and quality compared with the traditional algorithm. Especially, the data amount of plaintext images can be compressed by up to 8 times while achieving high decryption quality. To our best knowledge, CS reconstruction algorithms based on deep learning is firstly used for image encryption. Moreover, the proposed scheme is highly robust against occlusion, noise, and chosen-plaintext attack.
The asymmetric optical cryptosystems have been widely concerned due to their prominent characteristics of high security and robustness against attacks. In this paper, a resolution adaptative network ...is proposed to attack the asymmetric optical cryptosystems, which solves the issue of requiring a lot of experiments to change the network structure and parameters for effectively attacking to ciphertexts with different resolutions. The proposed network of fixing the network structure and parameters can be trained by inputting plaintext-ciphertext pairs with different resolutions, and then the trained network model can generate the retrieved plaintexts with corresponding resolutions. Numerical simulation and analysis show that the classical asymmetric optical cryptosystems can be attacked by the proposed network successfully. Moreover, the excellent resolution adaptability of the proposed network is verified by training and testing the images with different resolutions. Furthermore, the generalization ability and robustness of the proposed network is verified. In general, the issue of the input resolution adaptability of the cryptanalysis network is addressed firstly to our best knowledge.
Sodium montmorillonite has been modified via cation exchange reaction using gemini surfactants. Montmorillonite modified by cetyltrimethyl ammonium bromide (CTAB) is used for comparation. Basal ...spacings and thermal stability of these organo-montmorillonite clays have been characterized using X-ray diffraction analysis and thermogravimetric analysis. The d(001) spacings of montmorillonite-Gemini14, montmorillonite-Gemini16, montmorillonite-Gemini18 can reach above 35 Å compared with the 23.66 Å of the montmorillonite-CTAB at 2.2CEC. The thermogravimetric analysis show four-step degradation which corresponds to residual water desorption, dehydration, followed by decomposition of the organic modifier and the dehydroxylation of the organo-montmorillonite. In addition, DTG enables two different structural arrangements of gemini surfactant molecules intercalating the montmorillonite to be proposed that is different from montmorillonite-CTAB.
Plastisphere plays crucial role in global carbon and nitrogen cycles and microplastics formation. Global Municipal Solid Waste (MSW) landfills contain 42 % plastic waste, therefore representing one ...of the most significant plastispheres. MSW landfills are also the third largest anthropogenic methane sources and the important anthropogenic N2O source. Surprisingly, knowledge of microbiota and the associated microbial carbon and nitrogen cycles of landfill plastispheres is very limited. In this study, we characterized and compared the organic chemicals profile, bacterial community structure and metabolic pathway on plastisphere and the surrounding refuse in a large-scale landfill using GC/MS and 16S rRNA genes high-throughput sequencing, respectively. Landfill plastisphere and the surrounding refuse differed in organic chemicals composition. However, abundant phthalate-like chemicals were determined in both environments, implying the plastics additives leaching. Bacterial colonizing on the plastics surface had significantly higher richness than that in the surrounding refuse. Plastic surface and the surrounding refuse had distinct bacterial community composition. Genera of Sporosarcina, Oceanobacillus and Pelagibacterium were detected on the plastic surface with high abundance, while Ignatzschineria, Paenalcaligenes and Oblitimonas were rich in the surrounding refuse. Typical plastics biodegradation genus Bacillus, Pseudomonas and Paenibacillus were detected in both environments. However, Pseudomonas was dominant in plastic surface (up to 88.73 %), whereas Bacillus was rich in the surrounding refuse (up to 45.19 %). For the carbon and nitrogen cycle, plastisphere was predicted to had significant (P < 0.05) higher functional genes involved in carbon metabolism and nitrification, indicating more activated carbon and nitrogen microbial activity on the plastics surface. Additionally, pH was the main driver in shaping the bacterial community composition on plastic surface. These results indicate that landfill plastispheres serve as unique niches for microbial community habitation and function on microbial carbon and nitrogen cycles. These observations invite further study of the landfill plastispheres ecological effect.
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•Landfill plastisphere creates unique ecological niches for microbe inhabitation.•Landfill plastisphere had abundant phthalate-like chemicals.•Plastic surface and the surrounding refuse had distinct microbial structure.•Plastic surface had abundant plastics biodegradation Pseudomonas.•Plastisphere had higher activity in carbon metabolism and nitrification.
Municipal solid waste (MSW) landfills are significant sources of antibiotics. However, the effects of antibiotics on MSW decomposition process and methanogenesis during solid waste decomposition ...remain insufficiently characterized. This study investigated the effects of environmentally relevant concentrations (ERCs) of antibiotics (200 μg/kg for each antibiotic) on MSW decomposition and methanogenesis in bioreactors treated with and without eight antibiotics (three tetracyclines, three sulfonamides, and two macrolides). The key phases of MSW decomposition, namely the aerobic, anaerobic acid, and methanogenic phases, were determined by analyzing the key physiochemical parameters of the leachate, including pH, chemical oxygen demand, and biochemical oxygen demand. We assessed the bacterial and archaeal compositions, along with the abundance of the gene encoding the alpha subunit of methyl-coenzyme M reductase (mcrA), during MSW decomposition using high throughput 16S ribosomal RNA (rRNA) gene sequencing and quantitative polymerase chain reactions, respectively. Our results revealed that antibiotics significantly altered the compositions of bacteria and methanogens, leading to decreased mcrA abundance and methanogenesis. Specifically, antibiotics inhibited cellulose-degrading bacteria (Firmicutes) and archaea (E2) in the anaerobic acid phase and hydrolytic bacteria (Proteobacteria) in the methanogenic phase, resulting in lower degradation of biodegradable matter than that of the biodegradation without antibiotics treatment. However, the typical MSW decomposition process indicated by the key decomposition phases was successfully separated in both bioreactors, suggesting that antibiotics did not affect overall MSW decomposition process development or the associated individual decomposition phases establishment. These findings suggest that antibiotics at ERCs may inhibit methanogenesis during MSW decomposition, thereby providing fundamental information for methane management and climate change studies.
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•Antibiotics inhibited methanogenesis during MSW decomposition.•Antibiotics altered the microbial compositions during MSW decomposition.•Antibiotics did not affect overall MSW decomposition process development.
Anthropogenic activities significantly impact river ecosystem nutrient fluxes and microbial metabolism. Here, we examined the seasonal and spatial variation of sediments physicochemical parameters ...and the associated microbiome in the Pengxi river, a representative tributary of Three Gorges Reservoir, in response to seasonal impoundment and land use change by human activities. Results revealed that seasonal impoundment and land use change enhanced total organic carbon (TOC), total nitrogen (TN) and ammonium nitrogen (NH4+-N) concentration in the sediment, but have different effects on sediment microbiome. Sediment microbiota showed higher similarity during the seasonal high-water level (HWL) in consecutive two years. The abundant phyla Acidobacteria, Gemmatimonadetes, Cyanobacteria, Actinobacteria and Planctomycetes significantly increased as water level increased. Along the changes in bacterial taxa, we also observed changes in predicted carbon fixation functions and nitrogen-related functions, including the significantly higher levels of Calvin cycle, 4HB/3HP cycle, 3HP cycle and assimilatory nitrate reduction, while significantly lower level of denitrification. Though land use change significantly increased TOC, TN and NH4+-N concentration, its effects on spatial variation of bacterial community composition and predicted functions was not significant. The finding indicates that TGR hydrologic changes and land use change have different influences on the carbon and nitrogen fluxes and their associated microbiome in TGR sediments. A focus of future research will be on assessing on carbon and nitrogen flux balance and the associated carbon and nitrogen microbial cycling in TGR sediment.
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•TOC, TN and NH4+-N increased with seasonal impoundment and land use change.•Seasonal impoundment increased the sediment bacterial community similarity.•Seasonal impoundment increased carbon and nitrogen cycling genes.•Land use change does not change the sediments bacterial community structure.
Three Gorges Reservoir (TGR) water fluctuation creates high water level (HWL) and low water level (LWL) condition in TGR aquatic ecosystem. HWL fluies significant nutrients, mainly introducing carbon ...and nitrogen into the ecosystem. The nitrogen input is a concern for water quality management of TGR since the possible eutrophication caused by nitrogen spike. Sediment denitrification is widely recognized as the dominant nitrogen removal process in freshwater ecosystem. Therefore, the response of TGR sediments microbiome to the input nitrogen flucatution is crucial for both nitrogen balance and the eutrophication status of the ecosystem. Using high throughout sequencing of 16S rRNA gene and the predicted denitrification enzyme, and qualitative PCR of denitrification functional genes, we investigated how TGR sediments denitrification microbiome respond to the input nitrogen flux during two seasonal water fluctuation events. Concomitant to expected input carbon and nitrogen, we observed distinct microbial community structure and denitrification microbiota in HWL and LWL, and also in seasonal sampling events. Sediments pH, total nitrogen and nitrate were the significant impact factors in shaping the microbial community structure. Important denitrification microbiota (e.g., Saprospiraceae, Gemmatimonadaceae, Pseudomonas) are the main taxa of the microbial community and also showed water level and seasonal variation. The relative abundance of denitrification enzyme (nar, nir, nor, nos) and function genes (nirS, nirK, nosZ) were higher in LWL than HWL. Denitrification enzyme were significantly (p < 0.05) correlated with the nitrate concentration. In addition, the relative abundance of denitrification enzyme and function genes increased during the transition from 2014 HWL to 2015 LWL. Results suggested that TGR sediments denitrification is nitrate concentration dependent. The denitrification microbiome is initially inhibited due to high nitrate input, then they developed denitrification ability in response to high nitrate concentration.
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•TGR water fluctuation events flux significant nitrogen into the sediments.•Denitrification microbiota showed distinct structure in HWL and LWL.•Denitrification enzyme were significantly correlated with the nitrate concentration.•TRG sediments denitrification is nitrate concentration dependent.
With the development of quantum computers, difficult computational problems of classical cryptosystems could potentially become solvable. Hence, due to the powerful computing power of quantum ...computers, all current cryptographic algorithms based on computational complexity may become ineffective. Furthermore, most of the ciphertexts generated by traditional encryption schemes are noise-like, and such ciphertexts are easily suspected by cryptanalysts during transmission. To solve these problems, a novel image encryption scheme is proposed by visually meaningful ciphertext generation and quantum walks (QWs). The proposed scheme is composed of three phases: (I) Permutation, (II) Diffusion, and (III) Visually meaningful ciphertext generation. In phase I, the quantum substitution box (s-box) is firstly constructed by QWs, and the original image is permutated by the quantum s-box to reduce the correlation between adjacent pixels. In phase II, the permutated quantum image is diffused by a key image, which is constructed by the probability matrix generated by the same QWs. In phase III, the diffused image is disguised as a meaningful image to avoid the suspicions of cryptanalysts. Compared to traditional encryption algorithms, the introduction of quantum technology effectively improves the security of the cryptosystem. Compared to previous quantum encryption methods, our algorithm generates meaningful ciphertexts that can further enhance security by preventing cryptanalysts from suspecting noise-like ciphertexts. Thus, our encryption scheme is secure even in the future quantum computer age. Besides, the decryption time of our proposed scheme can also be effectively reduced since the decryption process can be optically implemented, partially. Therefore, real-time scenarios can be satisfied. Simulation results and numerical analysis show the effectiveness of the proposed scheme.
•Meaningful ciphertexts of the proposed scheme solving the problem of noisy ciphertexts of conventional quantum encryption schemes and avoiding the suspicion of cryptanalysts.•Improving the security of the proposed scheme even its meaningful ciphertext being discovered.•Effectively solving the problems of long iteration time and poor decryption quality in conventional scheme.
Anaerobic digestion (AD) is a microbial-mediated biogeochemical process that includes hydrolysis, acidogenesis, acetogenesis and methanogenesis. AD instability usually occurs in the transition from ...the acidogenesis phase (AP) to the methanogenesis phase (MP) due to over acidification. However, the underlying microbial mechanism of this transition has not been well characterized. In the present study, the transition of bacterial and methanogenic community composition, methanogenesis functional gene expression and metabolic pathways from AP to MP during food waste (FW) AD were investigated in a bioreactor using metagenomics and reverse transcription PCR technology. AP and MP were identified by changes in methane production, gas accumulation, pH and volatile fatty acids (VFAs). Concomitant with the changes in these physiochemical parameters, the bacterial and methanogenic community composition showed succession patterns. The bacterial composition transformed from acidogenic bacteria (Propionispira and Bacteroides) to hydrolytic bacteria (Smithella, Syntrophus and Syntrophorhabdus), and the methanogen composition transformed from the domination of acetoclastic methanogens (Methanosaeta) to the codomination of hydrogenotrophic methanogens (Methanoculleus, Methanolinea and Methanobacterium) and acetoclastic methanogens (Methanosaeta). The expression level of the methanogenesis functional gene mcrA significantly (p < 0.05) increased in response to the increasing methane production. In contrast, acetoclastic methanogenesis as the main methanogenesis metabolic pathway remained stable. These results showed that FWAD key physiochemical parameters drive the variation in microbial community composition and functional genes expression but not the methanogenesis metabolic pathway. The finding suggests that FWAD process may be better predicted by methanogenic functional characteristics than by microbial community composition.
•Acetoclastic methanogenesis pathway remained stable in transition.•The bacterial and methanogenic communities showed succession patterns.•Gene mcrA expression levels increased in response of the methane production.•Methanogenic function characteristics are suggested to predict AD process.
A municipal solid waste (MSW) landfill is a significant source of antibiotic resistance, pathogens and viruses and also a habitat for microbial consortia that perform MSW decomposition. Viruses are ...of great significance in ecological interactions such as MSW decomposition and antibiotic resistance gene (ARG) transmission. In this study, the viral community structure and the associated driver, the linkage of viruses and their bacterial hosts, the virus-associated ARG dissemination and virtual community function on MSW decomposition were investigated in landfill leachate from seven cities, China. The seven cities include four megacities, two large-scale cities and one small-scale city, representing the leachate characters of China. The results showed that the leachates were dominated by the phage families Siphoviridae, Myoviridae and Podoviridae (91.7 ± 3.6) %. Their putative hosts were the important MSW decomposers Lactobacillus, Pseudomonas, Clostridium, Proteiniphilum, and Bacteroides. The structure of the viral community was significantly affected by pH (P = 0.007, analyzed by RDA) and the bacterial community (R = 0.83, P < 0.001, analyzed by Mantel test). The relative abundance of ARGs showed a strong correlation (R > 0.8, P < 0.01) with viral family, suggesting that viruses play an important role in ARGs dissemination. Phage regulate bacterial population abundance through top-down effects, thus participating in MSW decomposition. These results demonstrate that viral community are involve in ARGs transmission and dissemination and mediate MSW decomposition in landfill.
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•The phages were the dominant group of the viral community.•Viral community structure was correlated with pH and the bacterial community.•Viral host was affiliated with the Municipal Solid Waste (MSW) decomposer.•Viruses were involved in antibiotic resistance genes dissemination.•Viral community impacts MSW decomposition through top-down effects.
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