Search Results (24)

This study explored the enzymatic formation of gel-like polymeric matrices through carbonate precipitation for dust suppression in Yellow River silt. The hydrogel-modified EICP method effectively enhanced the compressive strength and resistance to wind–rain erosion by forming a reinforced bio-cemented crust. The optimal cementation solution, consisting of urea and CaCl₂ at equimolar concentrations of 1.25 mol/L, was applied to improve CaCO₃ precipitation uniformity. A spraying volume of 4 L/m² (first urea-CaCl₂ solution, followed by urease solution) yielded a 14.9 mm thick hybrid gel-CaCO₃ crust with compressive strength exceeding 752 kPa. SEM analysis confirmed the synergistic interaction between CaCO₃ crystals and the gel matrix, where the hydrogel network acted as a nucleation template, enhancing crystal bridging and pore-filling efficiency. XRD analysis further supported the formation of a stable gel-CaCO₃ composite structure, which exhibited superior resistance to wind–rain erosion and mechanical wear. These findings suggest that gel-enhanced EICP represents a novel bio-gel composite technology for sustainable dust mitigation in silt soils. Full article

Soil, rhizosphere, and plant-associated microorganisms can enhance plant growth and health. A genomic analysis of these microbes revealed the key characteristics contributing to their beneficial effects. Following a field survey in Panama, four bacterial isolates with plant growth-promoting traits (PGPT) in rice (Oryza sativa L.) were identified. In this study, we sequenced, assembled, and annotated the genomes of Lysinibacillus fusiformis C6 and 24, and Bacillus cereus D23 and 59. The C6 genome was 4,754,472 bp long with 10 contigs, 37.62% guanine-cytosine (GC) content, and 4657 coding sequences (CDS). The 24 genome was 4,683,219 bp with five contigs, 37.65% GC content, and 4550 CDS. The D23 genome was 6,199,908 bp long with 18 contigs, 34.84% GC content, and 6141 CDS. The 59 genome was 6,194,462 bp with 21 contigs, 34.87% GC content, and 6122 CDS. Digital DNA–DNA hybridization (dDDH) and average nucleotide identity (ANI) confirmed that C6 and 24 belong to Lysinibacillus fusiformis, whereas D23 and 59 belong to the Bacillus cereus species. Further results revealed that these bacteria contained genes characteristic of plant growth-promoting bacteria, such as siderophore, phytohormone auxin (IAA) production, and nitrogen-fixing abilities that promote plant growth. Moreover, the antiSMASH database identified gene clusters involved in secondary metabolite production (biosynthetic gene clusters), such as betalactone, NRPS-like, NRP-siderophore, terpene, and RiPP-like clusters. Moreover, diverse and novel biosynthetic clusters (BCGs) have included non-ribosomal peptides (NRPs), polyketides (PKs), bacteriocins, and ribosomally synthesized and post-transcriptionally modified peptides (RiPPs). This work offers new insights into the genomic basis of the studied strains’ plant growth-promoting capabilities. Full article

Due to the large temperature fluctuations between day and night during the transition from winter to spring, soil sites in seasonally frozen soil areas go through repeated freeze–thaw cycles. During these cycles, the water in the soil undergoes phase transformation and migration, which changes the physical and mechanical properties of the soil and directly affects the stability and durability of the soil site. In order to explore the feasibility of using the ZDS-2 organosilicon reinforcement agent for the anti-freeze-and-thaw protection of soil sites, Qingtai site soil and the ZDS-2 organosilicon reinforcement agent were used as raw materials. The optimal ratio of modified soil samples with different freeze–thaw cycles was obtained by laboratory tests. The strengthening mechanism of the ZDS-2 organosilicon reinforcement agent under freeze–thaw cycles was revealed by a microscopic test. The test results showed that the ZDS-2 organosilicon reinforcement agent can inhibit the volume expansion of soil samples caused by the freeze–thaw cycle. After nine freeze–thaw cycles, the shear strength of the soil samples, to which 15% ZDS-2 organosilicon reinforcement agent was added, increased by 53.4% on average compared with plain soil. The highly cross-linked organic–inorganic hybrid network structure formed between the siloxane group in the ZDS-2 organosilicon reinforcement agent and the soil particles can fill the pores and form a protective layer. The experimental results provided a basis and reference for the research of freeze–thaw-resistant materials for soil sites in seasonally frozen soil areas. Full article

The contamination of soil with the heavy metal cadmium (Cd) is increasingly prominent and severely threatens food security in China. Owing to its low cost, suitable efficacy, and ability to address the shortcomings of plant remediation by enhancing the ability of plants to take up Cd, plant–microbe combination remediation technology has become a research hotspot in heavy metal pollution remediation. A pot experiment was performed to examine the effects of inoculation with the plant-growth-promoting bacterium Brevibacillus sp. SR-9 on the biomass, Cd accumulation, and soil nutrients of hybrid Pennisetum. The purpose of this study was to determine how Brevibacillus sp. SR-9 alleviates stress caused by heavy metal contamination. High-throughput sequencing and metabolomics were used to determine the effects of inoculation on the soil bacterial community composition and microbial metabolic functions associated with hybrid Pennisetum. The results suggest that mutation of Brevibacillus sp. SR-9 effectively alleviates Cd pollution stress, leading to increased biomass and accumulation of Cd in hybrid Pennisetum. The aboveground biomass and the root weight increased by 12.08% and 27.03%, respectively. Additionally, the accumulation of Cd in the aboveground sections and roots increased by 21.16% and 15.50%, respectively. Measurements of the physicochemical properties of the soil revealed that the strain Brevibacillus sp. SR-9 slightly increased the levels of available phosphorus, total nitrogen, total phosphorus, and available potassium. High-throughput DNA sequencing revealed that Brevibacillus sp. SR-9 implantation modified the composition of the soil bacterial community by increasing the average number of Actinobacteria and Bacillus. The total nitrogen content of the soil was positively correlated with the Actinobacteria abundance, total phosphorus level, and available phosphorus level. Metabolomic analysis revealed that inoculation affected the abundance of soil metabolites, and 59 differentially abundant metabolites were identified (p < 0.05). Among these, 14 metabolites presented increased abundance, whereas 45 metabolites presented decreased abundance. Fourteen metabolic pathways were enriched in these metabolites: the folate resistance pathway, the ABC transporter pathway, D-glutamine and D-glutamic acid metabolism, purine metabolism, and pyrimidine metabolism. The abundance of the metabolites was positively correlated with the levels of available phosphorus, total potassium, total phosphorus, and total nitrogen. According to correlation analyses, the development of hybrid Pennisetum and the accumulation of Cd are strongly associated with differentially abundant metabolites, which also impact the abundance of certain bacterial populations. This work revealed that by altering the makeup of microbial communities and their metabolic processes, bacteria that promote plant development can mitigate the stress caused by Cd. These findings reveal the microbiological mechanisms through which these bacteria increase the ability of hybrid Pennisetum to take up the Cd present in contaminated soils. Full article

Post-recycling sodium polyacrylate (SPA) derived from the selective recycling of personal hygiene products was tested as a potential key component of soil modifiers. Recycled SPA in combination with layered aluminosilicate (halloysite) with the sorption capacity of fertilizers allows for the creation of a fully functional, original system responsible for both water retention in soil and controlled dosing of fertilizers. The use of post-recycling SPA (possibly partially supplemented with virgin SPA) is advantageous for the natural environment. The results of different water types retention in post-recycling SPA (deionized water, rainwater, tap water) are discussed. The most beneficial effects of R-SPA swelling and water accumulation are achieved when it comes into contact with rainwater. The clear impact of Mg²⁺ ions on the sorption capacity of R-SPA introduces the need for a technological compromise between the solution composition (N, P, K or N, P, K, Mg) affecting its fertilization value and the possibility of obtaining maximum R-SPA swelling. The sorption capacity of R-SPA can be slightly increased by using R-SPA/V-SPA mixtures, but R-SPA still plays a decisive role in this system. The possibility of technological adjustment of the leaching rate of fertilizer components under dynamic conditions using different combinations of (R-SPA/V-SPA)/HAL was demonstrated by column tests. Full article

The prestressed concrete–steel hybrid (PCSH) support structure, which replaces the lower part of the traditional support with a concrete segment, is a prospective support structure solution for ultrahigh wind turbines. Taking a 5.5 MW wind turbine support structure founded on a jacket substructure with pile foundation as an example, an optimized design of the corresponding PCSH support structure with pile foundation for offshore wind turbine is conducted considering the soil–structure interaction (SSI) and the effect of water pressure. The construction cost of the proposed structure is treated as the objective function and minimized with a parallel modified particle swarm optimization (PMPSO) algorithm where the physical dimensions of each part of the PCSH wind turbine support structure are treated as optimization variables. Eleven optimization constraints are considered under both the serviceability limit state (SLS) and the ultimate limit state (ULS) according to relevant specifications and industry standards. A penalty function strategy is introduced to make sure that these constraints are fulfilled. The mechanical behavior and the cost of the optimal PCSH support structure with pile foundation are analyzed and are compared with those of the original design with a traditional steel tube tower founded on a jacket substructure. The results show that the cost and levelized cost of energy (LCOE), a comprehensive evaluation, of the optimized PCSH support decrease obviously with the PMPSO algorithm, which can provide advanced mechanic behavior including natural frequency, top deformation, and anti-overturning capacity. Compared with the PSO algorithm, the PMPSO algorithm has better performance in the procedure of PCSH support for offshore wind turbine optimization. Full article

Model calibration is essential for acceptable model performance and applications. The Hybrid-Maize model, developed at the University of Nebraska-Lincoln, is a process-based crop simulation model that simulates maize growth as a function of crop and field management and environmental conditions. In this study, we calibrated and validated the Hybrid-Maize model using soil moisture and yield data from eight commercial production fields in two years. We used a new method for the calibration and multi-parameter optimization (MPO) based on kriging with modified criteria for selecting the parameter combinations. The soil moisture-related parameter combination (SM-PC3) improved simulations of soil water dynamics, but improvement in model performance is still required. The grain yield-related parameter combination significantly improved the yield simulation. We concluded that the calibrated model is good enough for irrigation water management at the field scale. Future studies should focus on improving the model performance in simulating total soil water (TSW) dynamics at different soil depths by including more soil water processes in a more dynamic manner. Full article

Soil contamination through heavy metals (HMs) is a serious environmental problem that needs to be addressed. One of the methods of remediating soils contaminated with HMs and reducing the environmental risks associated with them is to immobilize these HMs in the soil using specific amendment(s). The use of biochar as an organic amendment can be an environmentally friendly and practically feasible option, as (i) different types of biomass can be used for biochar production, which contributes to environmental sustainability, and (ii) the functionality of biochar can be improved, enabling efficient immobilization of HMs. Effective use of biochar to immobilize HMs in soil often requires modification of pristine biochar. There are various physical, chemical, and biological methods for modifying biochar that can be used at different stages of pyrolysis, i.e., before pyrolysis, during pyrolysis, and after pyrolysis. Such methods are still being intensively developed by testing different modification approaches in single or hybrid systems and investigating their effects on the immobilization of HMs in the soil and on the properties of the remediated soil. In general, there is more information on biochar modification and its performance in HM immobilization with physical and chemical methods than with microbial methods. This review provides an overview of the main biochar modification strategies related to the pyrolysis process. In addition, recent advances in biochar modification using physical and chemical methods, biochar-based composites, and biochar modified with HM-tolerant microorganisms are presented, including the effects of these methods on biochar properties and the immobilization of HMs in soil. Since modified biochar can have some negative effects, these issues are also addressed. Finally, future directions for modified biochar research are suggested in terms of scope, scale, timeframe, and risk assessment. This review aims to popularize the in situ immobilization of HMs with modified biochar. Full article

Phosphorus deficiency highly interferes with plant growth and development. Plants respond to persistent P deficiency by coordinating the expression of genes involved in the alleviation of stress. Promoters of phosphate transporter genes are a great choice for the development of genetically modified plants with enhanced phosphate uptake abilities, which improve crop yields in phosphate-deficient soils. In our previous study, the sugarcane phosphate transporter PHT1;2 gene showed a significantly high expression under salinity stress. In this study, the Erianthus arundinaceus EaPHT1;2 gene was isolated and characterized using various in silico tools. The deduced 542 amino acid residues have 10 transmembrane domains, with a molecular weight and isoelectric point of 58.9 kDa and 9.80, respectively. They displayed 71–96% similarity with Arabidopsis thaliana, Zea mays, and the Saccharum hybrid. To elucidate the function of the 5′ regulatory region, the 1.1 kb promoter was isolated and validated in tobacco transgenics under Pi stress. The EaPHT1;2 promoter activity was detected using a β-glucuronidase (GUS) assay. The EaPHT1;2 promoter showed 3- to 4.2-fold higher expression than the most widely used CaMV35S promoter. The 5′ deletion analysis with and without 5′ UTRs revealed a small-sized 374 bp fragment with the highest promoter activity among 5′ truncated fragments, which was 2.7 and 4.2 times higher than the well-used CaMV35S promoter under normal and Pi deprivation conditions, respectively. The strong and short promoter of EaPHT1;2 with 374 bp showed significant expression in low-Pi-stress conditions and it could be a valuable source for the development of stress-tolerant transgenic crops. Full article

The increasing amount of rain produces a number of issues in Kerala, particularly in urban regions where the drainage system is frequently unable to handle a significant amount of water in such a short duration. Meanwhile, standard flood detection results are inaccurate for complex phenomena and cannot handle enormous quantities of data. In order to overcome those drawbacks and enhance the outcomes of conventional flood detection models, deep learning techniques are extensively used in flood control. Therefore, a novel deep hybrid model for flood prediction (DHMFP) with a combined Harris hawks shuffled shepherd optimization (CHHSSO)-based training algorithm is introduced for flood prediction. Initially, the input satellite image is preprocessed by the median filtering method. Then the preprocessed image is segmented using the cubic chaotic map weighted based k-means clustering algorithm. After that, based on the segmented image, features like difference vegetation index (DVI), normalized difference vegetation index (NDVI), modified transformed vegetation index (MTVI), green vegetation index (GVI), and soil adjusted vegetation index (SAVI) are extracted. The features are subjected to a hybrid model for predicting floods based on the extracted feature set. The hybrid model includes models like CNN (convolutional neural network) and deep ResNet classifiers. Also, to enhance the prediction performance, the CNN and deep ResNet models are fine-tuned by selecting the optimal weights by the combined Harris hawks shuffled shepherd optimization (CHHSSO) algorithm during the training process. This hybrid approach decreases the number of errors while improving the efficacy of deep neural networks with additional neural layers. From the result study, it clearly shows that the proposed work has obtained sensitivity (93.48%), specificity (98.29%), accuracy (94.98%), false negative rate (0.02%), and false positive rate (0.02%) on analysis. Furthermore, the proposed DHMFP–CHHSSO displays better performances in terms of sensitivity (0.932), specificity (0.977), accuracy (0.952), false negative rate (0.0858), and false positive rate (0.036), respectively. Full article

The ontogenesis and yield formation in crop plants are modified by environmental conditions. Due to climatic change detected over two decades, the harmful influence of abiotic factors is increasing. One of the most threatening issues reducing plant productivity is drought stress. The strength of plant response to water shortages could differ depending on the strength of the drought stress, type of crop, genetic background, presence of additional stresses, and stage of plant development. There are examples of sexual hybridization between crop plants like oat (Avena sativa L.) and maize (Zea mays L.) with which stable fertile hybrids were generated. Additional maize chromosomes in oat plants (oat × maize addition, OMA) often infer morphological and physiological (e.g., PS II photosystem activity and chlorophyll production) changes modulated by the interaction of certain maize chromosomes added to the oat genome. The aim of the research was to evaluate the chosen physiological, biochemical, and agronomic parameters of OMA plants subjected to soil drought. Analysis of variance indicated that the main effects of genotype as well as treatment × genotype interaction were significant for all the traits studied (photosynthetic pigment content, selected PSII indices, mass of stem, number of grains/plant, mass of grains/plant). Most of the examined lines severely reduced PSII photosystem parameters, pigment content, and yield-related traits under drought stress. The results indicated that two lines (9 and 78b) retained high yielding potential under drought stress compared to commercial cv. Bingo. Full article

We tried to estimate anthropogenic emission sources, including the contributions of neighboring regions, that affect the fine particle concentration (PM_2.5) in Daejeon using positive matrix factorization (PMF), concentration weight trajectory (CWT), and modified concentration weight trajectory (MCWT) models in a manner that might overcome the limitations of widely applied hybrid receptor models. Fractions of ion, carbonaceous compound and elements in PM_2.5 were 58%, 17%, and 3.6% during January and 49%, 17%, and 14.9% during May to June, respectively. The fraction of ions was higher during winter season, while the fraction of elements was higher during the other season. From the PMF model, seven factors were determined, including dust/soil, sea salt, secondary nitrate/chloride, secondary sulfate, industry, coal combustion, and vehicle sources. Secondary sulfate showed the highest contribution followed by secondary nitrate/chloride and vehicle sources. The MCWT model significantly improved the performance of regional contributions of the CWT model, which had shown a high contribution from the Yellow Sea where there are no emission sources. According to the MCWT results, regional contributions to PM_2.5 in the Daejeon metropolitan region were highest from eastern and southern China, followed by Russia, northeastern China, and Manchuria. We conclude that the MCWT model is more useful than the CWT model to estimate the regional influence of the PM_2.5 concentrations. This approach can be used as a reference tool for studies to further improve on the limitations of hybrid receptor models. Full article

The modified Cam-clay model (MCC model) is capable of representing the consolidation process of the soil under a complex stress path and thus is extensively adopted in the numerical analysis of excavation engineering. For reliability problems of ground surface settlement of excavation, minimal attention has been paid to investigating the effect of spatial variable MCC model parameters on the settlement during the staged construction of the excavation. Based on laboratory tests and sensitivity analysis, this study launched the probabilistic transient hydro-mechanical coupling analysis of excavation settlement considering spatial variable deformation parameters (λ and κ) using an MCS-FORM hybrid approach. The results show that: (1) Both the deformation parameters have a positive relationship with the settlement, and κ has a more significant effect than λ. (2) The observed maximum settlement and the location with maximum settlement follow a log-normal distribution. (3) An increasing COV of parameters leads to an enhanced surface settlement, expansion of the significant influence region, and decreased reliability. (4) The reliability index is greatly enhanced with the delimited controlled standard value of the surface settlement, H_con, and it decreases significantly at the preliminary stage and then decreases progressively until stable during excavating. Overall, adopting the deterministic analysis without considering the spatial variability of MCC parameters leads to underestimating the risk due to the settlement and the significant influence region. Full article

The modern rhythm of human life leads to well-known problems, which are air, water and soil pollution and climate warming. An increase in the power of industries and vehicles leads not only to atmospheric pollution by-products of incomplete fuel combustion but also to various microscopic particles that form aerosols, which carry an obvious danger to human health and also pollute the buildings’ facades. An environmentally friendly building material with a hybrid method “Nano-titania gradient” was developed. This method consists of forming a gradient of n-TiO₂ particles concentration in the composite since the physical properties of the composite are always inextricably linked to the geometry. To increase the efficiency of the photocatalytic process, a method of surface sensitization of titanium dioxide with the use of graphene oxide was proposed, which contributed to an increase in the overall photosensitivity. Thus, the decomposition of nitrogen oxide by volume with the modified surface increased by 27% in comparison with the classic titanium dioxide, and the decomposition of volatile organic substances increased by 32%. It was found that for the facade plate made with surface-sensitized TiO₂, the process of self-cleaning is completed after 3 h after the irradiation start. The modern rhythm of human life leads to well-known problems, which are air, water and soil pollution and climate warming. Using the theory of percolation, the concentration range of the photocatalyst content was calculated. To facilitate the material, waste cellulose was introduced. To increase the efficiency of the photocatalytic process, a method of surface sensitization of titanium dioxide (SS TiO₂) with the use of graphene oxide was proposed. The analysis of the experimental-statistical models of the compressive strength shows that the optimum content of TiO₂ was in the range from 0.8 to 1.1%, and cellulose from 0.4 to 0.8%, the optimum content of SS TiO₂ was in the range from 0.7 to 1.1%, and cellulose from 0.4 to 0.8%. Analysis of the experimental and statistical model of the bending strength shows that the optimal content of TiO₂ and SS TiO₂ was in the range of 0.6 to 1.0%, and cellulose from 0.4 to 0.8%. When studying the structure of composites, it was found that titanium dioxide was sorbed on the surface of swollen cellulose fibers and remained there after the process of cement hydration. The effectiveness of the method of surface sensitization of titanium dioxide by combining it with graphene oxide was shown. Thus, the decomposition of nitrogen oxide by volume with the modified surface increased by 27% in comparison with the classic titanium dioxide, and the decomposition of volatile organic substances increased by 32%. It was found that for the facade plate made with surface-sensitized TiO₂, the process of self-cleaning was completed after 3 h after the irradiation start. Full article

Hahella is one characteristic genus under the Hahellaceae family and shows a good potential for synthesizing new natural products. In this study, we examined the distribution of the secondary metabolite biosynthetic gene cluster (SMBGC) under Hahella with anti-SMASH. The results derived from five genomes released 70 SMBGCs. On average, each strain contains 12 gene clusters, and the most abundant ones (45.7%) are from the family of non-ribosomal peptide synthetase (NRPS) and non-ribosomal peptide synthetase hybrid with polyketide synthase (NRPS/PKS), indicating a great potential to find bioactive compounds. The comparison of SMBGC between H. chejuensis and other species showed that H. chejuensis contained two times more gene clusters than H. ganghwensis. One strain, designed as NBU794, was isolated from the mangrove soil of Dongzhai Port in Haikou (China) by iChip. The 16S rRNA gene of NBU794 exhibited 99% identity to H. chejuensis KCTC 2396 and clustered with the H. chejuensis clade on the phylogenetic trees. Genome mining on strain NBU794 released 17 SMBGCs and two groups of bioactive compounds, which are chejuenolide A-C and nine prodiginines derivatives. The prodiginines derivatives include the well-known lead compound prodigiosin and two new compounds, 2-methyl-3-pentyl-4-O-methyl-prodiginine and 2-methyl-3-octyl-prodiginine, which were identified through fragmentation analysis based on LC-MS/MS. The anti-microbial activity assay showed prodigiosin and 2-methyl-3-heptyl-prodiginine exhibited the best performance in inhibiting Escherichia coli, Salmonella paratyphi B, MASA Staphylococcus aureus, Bacillus subtilis, and Candida albicans. Moreover, the yield of prodigiosin in H. chejuensis NBU794 was also evaluated, which could reach 1.40 g/L under the non-optimized condition and increase to 5.83 g/L in the modified ISP4 medium with macroporous adsorption beads added, indicating that NBU794 is a promising source of prodigiosin. Full article