Search Results (106)

Slug-parasitic nematodes are promising biological control agents against gastropod pests, yet their responses to cereal root volatiles remain poorly understood. We evaluated the chemotactic behavior of Phasmarhabditis papillosa, Oscheius myriophilus, and Oscheius onirici toward synthetic standards of four barley root-derived VOCs—dimethyl sulfide (DMS), hexanal (H), 2-pentylfuran (2PF), and (E)-non-2-enal (N2E)—and their synthetic blends at two temperatures (18 °C and 22 °C). Significant species-specific and temperature-dependent differences were observed. 2PF and DMS consistently elicited the strongest attraction, particularly for O. myriophilus and P. papillosa, while aldehydes produced weaker or reduced-attraction responses. VOC blends often showed masking or antagonistic effects, suggesting complex signal integration. Temperature enhanced overall chemotactic activity, indicating its importance in modulating sensory behavior. These findings provide new insights into the chemical ecology of slug-parasitic nematodes and support the development of semiochemical-based biocontrol strategies tailored to species and environmental conditions. Full article

As conventional waterflooding enters mid-to-late stages, chemical enhanced oil recovery (EOR) technologies such as polymer–surfactant binary flooding have emerged to address declining recovery rates. This study systematically investigates the synergistic effects of polymer–surfactant binary formulations through core-flooding experiments under varying concentrations, injection volumes, and salinity conditions. The optimal formulation, identified as 0.5% surfactant and 0.15% polymer, achieves a maximum incremental oil recovery of 42.19% with an interfacial tension (IFT) reduction to 0.007 mN/m. A 0.5 pore volume (PV) injection volume balances sweep efficiency and economic viability, while sequential slug design with surfactant concentration gradients demonstrates superior displacement efficacy compared with fixed-concentration injection. Salinity sensitivity analysis reveals that high total dissolved solids (TDS) significantly degrade viscosity, whereas low TDS leads to higher viscosity but only marginally enhances the recovery. These findings provide experimental evidence for optimizing polymer–surfactant flooding strategies in field applications, offering insights into balancing viscosity control, interfacial tension reduction, and operational feasibility. Full article

Root-emitted volatile organic compounds (VOCs) play a critical role in below-ground ecological interactions by mediating communication between plants, pests, and their natural enemies. This study investigates the chemotactic behavior of three slug-parasitic nematode species—Phasmarhabditis papillosa, Oscheius myriophilus, and Oscheius onirici—in response to four carrot (Daucus carota) root-derived VOCs: α-pinene, terpinolene, bornyl acetate, and 2-ethyl-1-hexanol. Using a modified Petri dish assay, infective juveniles (IJs) were exposed to each compound across four concentrations (pure, 1000 ppm, 10 ppm, and 0.03 ppm), and their directional movement was quantified using a chemotaxis index (CI). The results revealed strong species-specific and concentration-dependent patterns. O. myriophilus exhibited the highest motility and repellency, particularly toward bornyl acetate and terpinolene, indicating its potential for use in VOC-guided biocontrol strategies. O. onirici showed moderate but consistent attraction to most VOCs, while P. papillosa exhibited generally weak or repellent responses, especially at higher concentrations. None of the compounds tested functioned as strong attractants (CI ≥ 0.2), suggesting that plant-derived VOCs alone may not be sufficient to direct nematode recruitment under field conditions. However, their integration with other biotic cues could enhance nematode-based “lure-and-infect” systems for sustainable slug control in carrot cropping systems. Full article

This study examined the effect of build orientation on the surface finish of micro-optofludic (MoF) devices fabricated via a polydimethylsiloxane (PDMS)-based 3D-printing primary–secondary fabrication protocol, where an inkjet 3D-printing technique was implemented. The molds (i.e., primaries) for fabricating the MoF devices were 3D-printed in two orientations: along $XY$ (Dev-1) and across $YX$ (Dev-2) the printhead direction. Next, the surface finish was characterized using a profilometer to acquire the primary profile of the surface along the microchannel’s edge. The results indicated that the build orientation had a strong influence on the latter, since Dev-1 displayed a tall and narrow Gaussian distribution for a channel width of 398.43 ± 0.29 µm; Dev-2 presented a slightly lower value of 393.74 ± 1.67 µm, characterized by a flat and broader distribution, highlighting greater variability due to more disruptive, orthogonally oriented, and striated patterns. These results were also confirmed by hydrodynamically testing the two MoF devices with an air–water slug flow process. A large experimental study was conducted by analyzing the mean period trend in the slug flow with respect to the imposed flow rate and build orientation. Dev-1 showed greater sensitivity to flow rate changes, attributed to its smoother, more consistent microchannel geometry. The slightly narrower average channel width in Dev-2 contributed to increased flow velocity at the expense of having worse discrimination capability at different flow rates. This study is relevant for optimizing 3D-printing strategies for the fabrication of high-performance microfluidic devices, where precise flow control is essential for applications in biomedical engineering, chemical processing, and lab-on-a-chip systems. These findings highlight the effect of microchannel morphology in tuning a system’s sensitivity to flow rate modulation. Full article

The increasing environmental and health concerns associated with synthetic pesticides underscore the need for sustainable alternatives in pest management. This study investigates the chemotactic responses of five nematode species—Heterorhabditis bacteriophora, Steinernema carpocapsae, Steinernema feltiae, Phasmarhabditis papillosa, and Oscheius myriophilus—to three major cannabinoids from Cannabis sativa: Δ⁹-tetrahydrocannabinol (THC), cannabigerol (CBG), and cannabidiol (CBD). Using a standardized chemotaxis assay, we quantified infective juvenile movement and calculated Chemotaxis Index (CI) values across varying cannabinoid concentrations. Our results revealed strong species-specific and dose-dependent responses. THC and CBG elicited significant attractant effects in P. papillosa, S. feltiae, and H. bacteriophora, with CI values ≥ 0.2, indicating their potential as behavioral modulators. In contrast, CBD had weaker or repellent effects, particularly at higher concentrations. O. myriophilus exhibited no consistent response, underscoring species-specific variation in chemosensory sensitivity. These findings demonstrate the potential utility of cannabinoids, especially THC and CBG, as biocompatible cues to enhance the efficacy of nematode-based biological control agents in integrated pest management (IPM). Further field-based studies are recommended to validate these results under realistic agricultural conditions. Full article

To address the challenges of low displacement efficiency and gas channeling in the Lukqin thick oil reservoir, characterized by high viscosity (286 mPa·s) and strong heterogeneity (permeability contrast 5–10), this study systematically investigated water flooding and foam flooding mechanisms using a large-scale 2D sandpack model (5 m × 1 m × 0.04 m). Experimental results indicate that water flooding achieves only 30% oil recovery due to a mobility ratio imbalance (M = 128) and preferential channeling. In contrast, foam flooding enhances recovery by 15–20% (final recovery: 45%) through synergistic mechanisms of dynamic high-permeability channel plugging and mobility ratio optimization. By innovatively integrating electrical resistivity tomography with HSV color mapping, this work achieves the first visualization of foam migration pathways in meter-scale heterogeneous reservoirs at a spatial resolution of ≤0.5 cm, reducing monitoring costs by approximately 30% compared to conventional CT techniques. Key controlling factors for gas channeling (injection rate, foam quality, permeability contrast) are identified, and a nonlinear predictive model for plugging strength ((S = 0.70C^0.6 k_r^−0.28) (R² = 0.91)) is established. A composite optimization strategy—combining high-concentration slugs (0.7% AOS), salt-resistant polymer-enhanced foaming, and multi-round profile control—achieves a 67% reduction in gas channeling. This study elucidates the dynamic plugging mechanisms of foam flooding in heterogeneous thick oil reservoirs through large-scale physical simulations and data fusion, offering direct technical guidance for optimizing foam flooding operations in the Lukqin Oilfield and analogous reservoirs. Full article

Slugs are significant agricultural pests, causing extensive crop damage and economic losses. While chemical molluscicides are commonly used for control, concerns about their environmental impact have driven interest in alternative methods, including beer traps. This study evaluated the effectiveness of different beer types as attractants for slug trapping in field conditions over two consecutive years (2022–2023). Five types of beer—Union Lager, Paulaner Weissbier, BrewDog Punk IPA, Guinness Draught, and Chimay Blue—were tested alongside ethanol (10%) and a control treatment. The results demonstrated that Paulaner Weissbier and Union Lager were the most effective attractants, followed by Guinness Draught and Chimay Blue, while BrewDog Punk IPA had moderate effectiveness. Ethanol (10%) and the control treatment failed to attract slugs, confirming that volatile compounds, rather than alcohol alone, drive slug attraction. Gas chromatography–mass spectrometry (GC-MS) analysis revealed that Paulaner Weissbier contained high levels of isoamyl acetate and limonene, while Union Lager exhibited elevated ethyl esters, which likely contributed to their effectiveness. Environmental factors influenced slug activity, with higher temperatures correlating with increased slug capture rates, while precipitation had no significant effect. These findings highlight the role of fermentation-derived volatile compounds in slug attraction and suggest that optimizing beer traps based on beer composition and environmental conditions could improve their effectiveness as a non-chemical slug control method. Future research should explore the long-term stability of beer attractants, the potential of synthetic formulations, and alternative yeast-based attractants to enhance slug management strategies. Full article

Topside choking is a common way to eliminate severe slugging flow in pipeline riser systems in offshore oil and gas fields. However, a lack of fundamentals in two-phase flow gives rise to difficulty in the model selection of valves and the effective control of the valves. In this study, the prediction of the valve opening required for slugging control based on measurable parameters is investigated experimentally and theoretically. It is found that the resistance coefficient factor of the valve is almost the same for pipeline risers and simple vertical pipes when severe slugging is eliminated. Therefore, fluid parameters can be approximated by the conditions of a simple vertical pipe. The target of control is to achieve dual-frequency fluctuation, and it is quantitatively converted to the pressure drop of the valve. Based on these two empirical enclosures, the valve opening can be worked out by using the gas fraction model and the theoretical model of valve flow resistance. The non-slip model is found to be better than the drift-flux model in the final prediction of the optimal valve opening. An explicit model for the calculation of the optimal resistance factor and the corresponding valve opening is established, making it more convenient to select the valve in the design stage of offshore oil and gas exploitation. The average absolute error of the proposed model is +0.01%, which is smaller than the simulation performed by OLGA 7.0 software (+4.91% before tuning and +0.08% after tuning). A field case with a flexible S-shape riser proves the good applicability of the model (with a deviation smaller than ±2%). The applications of the prediction model in the model selection of the valve and uncertain factors in the operation are also discussed. Full article

The process of epithelial–mesenchymal transition (EMT) is crucial in various physiological/pathological circumstances such as development, wound healing, stem cell behavior, and cancer progression. It involves the conversion of epithelial cells into a mesenchymal phenotype, which causes the cells to become highly motile. This reprogramming is initiated and controlled by various signaling pathways and governed by several key transcription factors, including Snail 1, Snail 2 (Slug), TWIST 1, TWIST2, ZEB1, ZEB2, PRRX1, GOOSECOID, E47, FOXC2, SOX4, SOX9, HAND1, and HAND2. The intracellular signaling pathways are activated/inactivated by signals received from the extracellular environment and the transcription factors are carefully regulated at the transcriptional, translational, and post-translational levels to maintain tight regulatory control of EMT. One of the most important pathways involved in this process is the transforming growth factor-β (TGFβ) family signaling pathway. This review will discuss the role of EMT in promoting epithelial cancer progression and the convergence/interplay of multiple signaling pathways and transcription factors that regulate this phenomenon. Full article

Parasitic nematodes play a vital role in soil ecosystems, contributing to natural pest suppression. Among them, slug-parasitic species such as Phasmarhabditis papillosa (Schneider) Andrassy, Oscheius myriophilus (Poinar), and Oscheius onirici Torrini et al. are promising biological control agents against mollusk pests. These nematodes rely on plant-emitted volatile organic compounds (VOCs) for host location, yet their chemotactic responses to specific VOCs remain unclear. This study assessed the responses of P. papillosa, O. myriophilus, and O. onirici to VOCs emitted by potato (S. tuberosum) tubers under varying temperature (18 °C, 22 °C) and concentration conditions (pure compound, 0.03 ppm). The results indicate that octanal was the strongest attractant, particularly for O. myriophilus, while nonanal exhibited species-dependent effects. Hydrocarbons such as undecane and 1,2,4-trimethylbenzene had minimal or repellent effects, whereas 6-methyl-5-hepten-2-one showed moderate attraction. Chemotactic responses were stronger at 18 °C, and attraction increased with higher VOC concentrations, suggesting a threshold-dependent response. These findings enhance our understanding of plant–nematode interactions and suggest that octanal and 6-methyl-5-hepten-2-one could improve nematode-based slug control strategies. However, environmental factors such as soil composition and microbial activity may influence VOC diffusion and nematode recruitment. Future research should focus on optimizing VOC formulations, assessing field applicability, and integrating these findings into sustainable pest management programs. Full article

The conventional polymer gel has high initial viscosity and short gelation time, making it difficult to meet the requirements of deep profile control in offshore reservoirs with large well spacing and strong heterogeneity. This paper evaluates the performance and core plugging capacity of novel functional polymer gels and microspheres to determine the applicability of core permeability ranges. On the heterogeneous core designed based on the reservoir characteristics of Block B oilfield, optimization was conducted separately for the formulation, dosage, and slug combinations of the polymer gel/microsphere. Finally, oil displacement experiments using polymer and microsphere combinations were conducted on vertically and planar heterogeneous cores to simulate reservoir development effects. The experimental results show the novel functional polymer gel exhibits slow gelation with high gel strength, with viscosity rapidly increasing four days after aging, ultimately reaching a gel strength of 74,500 mPa·s. The novel functional polymer gel and polymer microsphere can effectively plug cores with permeabilities below 6000 mD and 2000 mD, respectively. For heterogeneous cores with an average permeability of 1000 mD, the optimal polymer microsphere has a concentration of 4000 mg/L and a slug size of 0.3 PV; for heterogeneous cores with an average permeability of 4000 mD, the optimal functional polymer gel has a concentration of 7500 mg/L and a slug size of 0.1 PV. In simulations of vertically and planarly heterogeneous reservoirs, the application of polymer agent increases the oil recovery factor by 53% and 38.7% compared to water flooding. This realizes the gradual and full utilization of layers with high, medium, and low permeability. Full article

As global energy demand continues to grow, the difficulty and cost of extracting oil and gas resources are gradually increasing, making enhanced oil recovery (EOR) one of the key issues in oil and gas field development. CO₂ flooding, as an effective tertiary oil recovery technique, has significant advantages in improving recovery rates due to its ability to significantly reduce crude oil viscosity, increase formation energy, and expand the swept volume. However, the effectiveness of CO₂ flooding is influenced by various factors, including flooding methods, well patterns, and formation parameters. In this study, a two-dimensional high-temperature and high-pressure simulation device was used to simulate the CO₂ flooding process under various flooding methods, including water flooding followed by continuous gas flooding, water–gas alternating flooding, and foam flooding, for two types of injection–production well patterns based on the formation oil parameters of the Hei 125 block in the Daqingzijing Oilfield. The results indicate that during the transition from water flooding to continuous gas flooding, gas breakthrough channels form rapidly, leading to a rapid increase in the produced gas–oil ratio (GOR). Alternatively, alternating injection of gas and liquid can effectively control gas mobility, reduce gas phase permeability, delay gas breakthrough time, and improve oil displacement efficiency. Water–gas alternating flooding forms water–gas slugs, allowing CO₂ to enter the tiny pores to contact crude oil, reducing resistance in the pores, and enhancing crude oil displacement efficiency. Although the foam system can expand the fluid sweep range, excessive gas injection can lead to premature gas breakthrough. Furthermore, the type of injection–production well pattern has a significant impact on the overall reservoir recovery for foam system and gas alternating flooding with a 1:1 ratio; adjusting the well pattern can increase the sweep efficiency and improve ultimate recovery. This study reveals the mechanisms by which different flooding methods and well patterns affect the effectiveness of CO₂ flooding, providing important theoretical and practical guidance for optimizing flooding strategies and improving oil recovery in oil and gas fields. It is of great significance for promoting the application of CO₂ flooding technology in oil and gas field development. Full article

The Bohai oilfield is characterized by severe heterogeneity and high average permeability, leading to a low water flooding recovery efficiency. Polymer flooding only works for a certain heterogeneous reservoir. Therefore, supplementary technologies for further enlarging the swept volume are still necessary. Based on the concept of discontinuous chemical flooding with multi slugs, three chemical systems, which were polymer gel (PG), hydrophobically associating polymer (polymer A), and conventional polymer (polymer B), were selected as the profile control and displacing agents. The optimization design of the discontinuous chemical flooding was investigated by core flooding experiments and displacement equilibrium degree calculation. The gel, polymer A, and polymer B were classified into three levels based on their profile control performance. The degree of displacement equilibrium was defined by considering the sweep conditions and oil displacement efficiency of each layer. The effectiveness of displacement equilibrium degree was validated through a three-core parallel displacement experiment. Additionally, the parallel core displacement experiment optimized the slug size, combination method, and shift timing of chemicals. Finally, a five-core parallel displacement experiment verified the enhanced oil recovery (EOR) performance of discontinuous chemical flooding. The results show that the displacement equilibrium curve exhibited a stepwise change. The efficiency of discontinuous chemical flooding became more significant with the number of layers increasing and heterogeneity intensifying. Under the combination of permeability of 5000/2000/500 mD, the optimal chemical dosage for the chemical discontinuous flooding was a 0.7 pore volume (PV). The optimal combination pattern was the alternation injection in the form of “medium-strong-weak-strong-weak”, achieving a displacement equilibrium degree of 82.3%. The optimal shift timing of chemicals occurred at a water cut of 70%, yielding a displacement equilibrium degree of 87.7%. The five-core parallel displacement experiment demonstrated that discontinuous chemical flooding could get a higher incremental oil recovery of 24.5% compared to continuous chemical flooding, which presented a significantly enhanced oil recovery potential. Full article

Terrestrial slugs and snails can significantly harm agriculture. Due to environmental concerns associated with chemical molluscicides, biological control methods are increasingly being explored. Oscheius myriophilus (Poinar, 1986), a nematode species recently discovered in association with Arion vulgaris Moquin-Tandon, 1855, holds promise as a biocontrol agent for gastropod pests. In this study, we investigated the chemotactic response and motility of O. myriophilus when exposed to the mucus of five mollusk species: Helix pomatia Linnaeus, 1758, Cernuella virgata (Da Costa, 1778), Deroceras reticulatum Müller, 1774, A. vulgaris, and Tandonia budapestensis Hazay, 1880. Our experiments were conducted at two temperatures (20 °C and 25 °C) to assess how environmental conditions influence nematode behavior. The results demonstrated that the chemoattractiveness of mollusk mucus to O. myriophilus was significantly influenced by both the species of mollusk and the temperature. Overall, nematode motility was higher at 20 °C than at 25 °C, indicating that lower temperatures may enhance the activity of O. myriophilus. Among the tested mollusk species, C. virgata mucus consistently attracted the highest number of nematodes, especially at the lower temperature. Our findings indicate that the chemotactic response of O. myriophilus to mollusk mucus may have potential for the targeted biocontrol of pest mollusks. While C. virgata demonstrated strong attractant potential at the tested temperatures, particularly under cooler conditions (20 °C), further research is needed to confirm whether this represents a consistent temperature-related effect. Future studies should aim to identify the specific chemical cues in mollusk mucus that trigger nematode attraction and examine how these signals interact with a broader range of environmental variables, including temperature, to influence nematode behavior. Full article

Alternating carbon dioxide and water flooding can not only seal greenhouse gases, but also combine the advantages of water flooding and carbon dioxide flooding, and can well control mobility and stabilize the displacement front, thereby greatly improving the macro-replacing efficiency. In order to further improve the development effect of water–carbon dioxide alternating flooding, this paper, based on sufficient collection of the literature, research, and analysis, pre-uses modified water instead of water, and deeply explores and studies the impact of modified water–carbon dioxide alternating flooding on the improvement of development effect and the mechanism of enhancing oil recovery in low-permeability reservoirs. The main work completed is as follows: (1) A comparative experiment of multiple groups of sand-filled tubes with different displacement media, modified water concentrations, and injection plug sizes was conducted under the conditions of simulating reservoir formation temperature of 70 °C and formation pressure of 18 MPa, and the optimal scheme and injection parameters of alternating modified water and carbon dioxide flooding were rationally selected. The results show that the alternating flooding of modified water and carbon dioxide in low-permeability reservoirs can significantly improve the development effect. The optimal injection parameters are a formulation concentration of 0.3% and an injection method of alternating a 0.1 PV slug injection of carbon dioxide and modified water. (2) Using Berea cores instead of sand-fill tubes, a comparative experiment of alternating oil displacement using carbon dioxide and modified water was carried out under the same experimental conditions. Nuclear magnetic resonance measurements were performed on five of the cores to analyze the microscopic oil displacement mechanisms of different displacement media. The results show the following: nuclear magnetic resonance testing shows that carbon dioxide displacement can greatly improve the oil recovery efficiency in tiny pores (about 47.43%); alternating injection can further improve the oil recovery efficiency in tiny pores (about 70.6%); and modified water can improve the oil recovery efficiency in larger pores (about 56.47%). Full article