65 research outputs found
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ACRYLONITRILE HAS DISTINCT HORMETIC EFFECTS ON ACETYLCHOLINESTERASE ACTIVITY IN MOUSE BRAIN AND BLOOD THAT ARE MODULATED BY ETHANOL
Acrylonitrile(AN) is a neurotoxin both in animals and humans, but its effects on acetylcholinesterase (AChE) activity remain controversial. This study aimed to determine the dose-response effects of AN on AChE activity and the modulatory role of ethanol pretreatment. A total of 144 Kunming mice were randomly divided into 18 groups: nine groups received 5% ethanol in their drinking water, and the remaining nine groups received regular tap water. One week later, both the ethanol and tap water only groups were given an intraperitoneal injection of AN at the following doses: 0 (control), 0.156, 0.3125, 0.625, 1.25, 2.5, 5, 10 or 20 mg AN/kg body weight. AChE activity was determined on whole blood and brain 24 h later. Blood AChE activity was higher in AN-injected mice than in controls at all doses. AChE activity in blood increased in a dose-dependent manner, peaking at 0.156 mg/kg, after which a gradual decrease ensued, displaying a β-typed dose-response relationship. In contrast, brain AChE activity, following a single AN injection, was consistently lower than in control mice, and continued to fall up to a dose of 0.313 mg/kg, and thereafter increased gradually with higher doses. Mice receiving a 20 mg/kg dose of AN exhibited AChE brain activity indistinguishable from that of control mice, demonstrating a typical U-typed dose-response relationship. The activity of AChE in the blood and brain of the AN + ethanol-treated groups displayed a shift to the right, and the magnitude of the decrease in AChE activity induced by AN was attenuated relative to the AN-only group. These results suggest that AN affects AChE activity in both mouse blood and brain in a hormetic manner. Pretreatment with ethanol modifies the effect of AN on AChE, indicating that parent AN has a more prominent role than its metabolites in modulating enzyme activity
An aphid-transmitted polerovirus is mutualistic with its insect vector by accelerating population growth in both winged and wingless individuals
The occurrence and increased dispersion of plant viruses and insect vectors are serious global threat to the production of agricultural crops. Facing novel pathogenic plant viruses, the ability to accurately identify plant virus species, and understand the interaction between plant viruses, host plants and their insect vectors would provide an important basis for formulating effective plant virus control measures. In this study, we explored the transmission mechanism, pathogenic symptoms, host range and the interactions between virus and aphid vectors of a novel polero virus from Nicotianatabacum, named Tobacco yellow virus (TYV). The results indicate that TYV can be transmitted by Myzus persicae in a persistent manner, and cause yellowing and shrinking of tobacco leaves. TYV can successfully infect a total of 9 plant species belonging to 3 families. The effect of TYV-infected tobacco plants on M. persicae behavior and life characteristics was found to be stage-dependent. TYV can directly and indirectly manipulate the performance and life history traits of M. persicae vectors to promote their own transmission. These results provide a certain theoretical basis for the possibility of control strategies of the virus, and the in-depth exploration of the interaction among plant virus, vector aphid and host plants
Global patterns in genomic diversity underpinning the evolution of insecticide resistance in the aphid crop pest Myzus persicae
Abstract: The aphid Myzus persicae is a destructive agricultural pest that displays an exceptional ability to develop resistance to both natural and synthetic insecticides. To investigate the evolution of resistance in this species we generated a chromosome-scale genome assembly and living panel of >110 fully sequenced globally sampled clonal lines. Our analyses reveal a remarkable diversity of resistance mutations segregating in global populations of M. persicae. We show that the emergence and spread of these mechanisms is influenced by host–plant associations, uncovering the widespread co‐option of a host-plant adaptation that also offers resistance against synthetic insecticides. We identify both the repeated evolution of independent resistance mutations at the same locus, and multiple instances of the evolution of novel resistance mechanisms against key insecticides. Our findings provide fundamental insights into the genomic responses of global insect populations to strong selective forces, and hold practical relevance for the control of pests and parasites.Peer reviewedFinal Published versio
Co-composting: An Opportunity to Produce Compost with Designated Tailor-Made Properties
AbstractCo-composting is a technique that allows the aerobic degradation of organic waste mixtures, primarily aiming at obtaining compost that can be used as fertiliser or soil amendment. As compared to the typical composting activity, the main difference is not merely the use of more than one feedstock to start and sustain the biodegradation process, but also the possibility of combining various kinds of waste to obtain 'tailored' products with designed properties, or to reclaim and valorise natural resources, such as degraded soils or polluted soils and sediments. Set up of appropriate co-composting protocols can be a way to optimise the management of waste produced by different sectors of agriculture and industry and also from human settlements. Different formulations can not only optimise the biodegradation process through the adjustment of nutrient ratios, but also lead to the formation of products with innovative properties. Moreover, co-composting can be a technique of choice for the reclamation of soils degraded by intensive agriculture or contaminated soils and sediments. In fact, an appropriate mix of organic waste and soils can restore the soil structure and induce fertility in nutrient-depleted soils, and also remediate polluted soils and sediments through degradation of organic pollutants and stabilisation of heavy metals. While the selection of different mixes of organic waste may lead to the design of composts with specific properties and the potential valorisation of selected waste materials, there are still several factors that hamper the development of co-composting platforms, mainly insufficient knowledge of some chemical and microbiological processes, but also some legislative aspects. This chapter illustrates the progress achieved in co-composting technology worldwide, some key legislative aspects related to the co-composting process, the main scientific and technical aspects that deserve research attention to further develop co-composting technology, and successful applications of co-composting for the reclamation of soils and sediments, allowing their use for cultivation or as growing media in plant nurseries. A specific case study of the production of fertile plant-growing media from sediment co-composting with green waste is also illustrated
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Dynamics of supercritical CO₂ foam in porous media with CO₂ soluble surfactants
CO₂ flood has become a routine technology for enhanced oil recovery worldwide. However, the problem of poor sweep efficiency has been frequently encountered in CO₂ flooding due to the presence of preferential flow paths such as high permeability zones or fracture networks. The objective of this work is to improve robustness of supercritical CO₂ foam as a mobility controlling agent, surfactant utilization, and reservoir sweep efficiency in CO₂ flooding. The focus will be the unconventional foam process with proprietary non-ionic CO₂ soluble surfactants. The properties of these surfactants including solubility in CO₂, partitioning between CO₂ and water phases, and static adsorption on rock are directly measured versus temperatures and pressures. For the first time the unconventional foam process with CO₂ soluble surfactant has been systematically studied from the viewpoint of foam improved CO₂ flood and compared with conventional foam (stabilized with a widely used conventional CO₂ insoluble surfactant. Both Silurian carbonates and Berea sandstones were used in this study. The effect of reservoir heterogeneity such as stratification and natural fractures are also investigated. For the first time, foam behavior is probed in fractured system with variable fracture apertures, foam qualities, injection rates and rock permeabilities. Micro-scaled model is also developed to visualize foam propagation in fracture flow. All the measured surfactant properties are then used to model foam transport on a field scale using a commercial reservoir simulation. The advantages of CO₂ soluble surfactants are quantified for different injection strategies. Optimization of surfactant partition coefficient for field-scale foam process is performed to determine the variation of surfactant partitioning effect. A new method is proposed, which can be used in conjunction with the cloud point measurements, to obtain information directly on the soluble portion of a given sample. The partitioning of nonionic hydrocarbon surfactants between water and brine and CO₂ as a function of electrolyte concentration, temperature and pressure are also investigated. These functional relationships have been rarely found in the literature. The solubility of the non-ionic surfactant in CO₂ increases with pressure and gradually decreases with temperature. The partitioning of this surfactant between CO₂ and water phases is much more sensitive to temperature than pressure. Strong foam development in Silurian cores is observed for both non-ionic and anionic surfactants while the adsorption of the latter surfactant is almost three times higher. The foam with CO₂ soluble surfactants is much more robust in water displacement due to both reduced surfactant adsorption and surfactant partitioning. However, the adsorption magnitudes of the non-ionic and anionic surfactants are very close in sandstone, but foam with CO₂ soluble surfactants still outperforms that with conventional surfactants because of surfactant partitioning. A new experimental method to determinate dynamic CO₂ foam in artificially fractured carbonate cores at high pressure is presented. The rheology of foam in fractures is well distinguished from that in matrix. Foam propagation decreases with increasing fracture aperture at very low shear rate. However, this relationship is strongly influenced by matrix permeability. A strong correlation between foam performance and injection quality was not observed an increase in total injection rate promote foam development. In agreement with the above experimental observations, foam with CO₂ soluble surfactant on a field scale can improve injectivity, surfactant transport, and foam propagation in regions where CO₂ mobility control is needed. The benefit of co-injection and alternating injection could be significantly enhanced with CO₂ soluble surfactant. The ability of surfactant to partition between CO₂ and water phase reduces the effect of gas and water slug sizes on foam performance. A new injection strategy where surfactant is injected in CO₂ without water injection gives the highest sweep efficiency. This particular foam process shows best performance under constant rate injection mode. Foam performance and surfactant transport is governed not only by constrained injection strategies, but also surfactant partition coefficient. Both experiments and simulations demonstrate that good surfactant transport with CO₂ soluble surfactant improves foam robustness once local surfactant concentration exceeds a critical concentration. The CO₂ soluble surfactant and its injection strategies presented in this work not only improve the robustness of foam performance but also reduce the overall cost of foam process. The optimal partition of the surfactant between the CO₂ and aqueous phases minimize the loss of expensive surfactant in water that is never contacted with CO₂. The results from this study enable us to tailor properties of CO₂ soluble surfactants (i.e. partition coefficient and solubility in CO₂) to a wide range of reservoir conditions and optimal injection strategies. This novel CO₂ soluble surfactant concept diversifies injection strategies with respect to operational constraints, broadening the application of foam process.Petroleum and Geosystems Engineerin
Understanding aqueous foam with novel CO2-soluble surfactants for controlling CO2 vertical sweep in sandstone reservoirs
Abstract The ability of a novel nonionic CO2-soluble surfactant to propagate foam in porous media was compared with that of a conventional anionic surfactant (aqueous soluble only) through core floods with Berea sandstone cores. Both simultaneous and alternating injections have been tested. The novel foam outperforms the conventional one with respect to faster foam propagation and higher desaturation rate. Furthermore, the novel injection strategy, CO2 continuous injection with dissolved CO2-soluble surfactant, has been tested in the laboratory. Strong foam presented without delay. It is the first time the measured surfactant properties have been used to model foam transport on a field scale to extend our findings with the presence of gravity segregation. Different injection strategies have been tested under both constant rate and pressure constraints. It was showed that novel foam outperforms the conventional one in every scenario with much higher sweep efficiency and injectivity as well as more even pressure redistribution. Also, for this novel foam, it is not necessary that constant pressure injection is better, which has been concluded in previous literature for conventional foam. Furthermore, the novel injection strategy, CO2 continuous injection with dissolved CO2-soluble surfactant, gave the best performance, which could lower the injection and water treatment cost
Ocena opartej na modelu obciążeniowo-wytrzymałościowym ważności elementów systemu szeregowego z uwzględnieniem uszkodzeń wywołanych wspólną przyczyną
Series systems, whose structures are simple, are widely discovered in practical engineering, but the interdependency between the components is complex, such as common cause failure. With the consideration of the components’ strength, this paper focuses on ranking the importance measure of components considering the common cause failure based on the stress-strength interference (SSI) model. The weakest component can be identified by integrating the SSI model with the importance measure when the strength mean and variance of the component under the load stress is known. Firstly, the analytic methods are proposed to calculate the SSI-based importance of components in the series systems. Then, the monotonicity of SSI-based importance is analyzed by changing the strength mean or strength variance of one component. The results show that the SSI-based importance of components, whose parameters are changed, will reduce monotonically with the increase of strength mean or increase monotonically with the increase of strength variance. Finally, a component replacement method is developed based on the rules that both the importance of replaced component and the importance ranks should be unchanged after the replacement. SSI-based importance can help engineers to make maintenance decisions, and the component replacement method can increase the diversity of spare parts by finding the equivalent components.Systemy szeregowe, które są szeroko stosowane w praktyce inżynieryjnej, charakteryzują się prostą strukturą, jednak współzależności między ich elementami są złożone, czego przykładem są uszkodzenia wywołane wspólną przyczyną. Rozważając wytrzymałości składowych systemu, opracowano metodę szeregowania miar ważności składowych z uwzględnieniem uszkodzeń wywołanych wspólną przyczyną. Metoda ta pozwala zidentyfikować najsłabsze ogniwo systemu. Miarę istotności zintegrowano z modelem obciążeniowo-wytrzymałościowym (SSI), biorąc pod uwagę średnią i wariancję wytrzymałości elementu pod obciążeniem. W pierwszym kroku opracowano metody analityczne pozwalające na obliczanie opartej na SSI ważności elementów w systemach szeregowych. Następnie analizowano monotoniczność opartej na SSI ważności zmieniając średnią lub wariancję wytrzymałości jednego z elementów. Wyniki pokazują, że mierzona w oparciu o SSI ważność elementów, których parametry są zmieniane, maleje monotonicznie wraz ze wzrostem średniej wytrzymałości lub rośnie monotonicznie wraz ze wzrostem wariancji wytrzymałości. Na podstawie przeprowadzonych badań, opracowano metodę wymiany części, opartą na zasadzie polegającej na tym, że zarówno ważność zastąpionego elementu, jak i rangi ważności powinny pozostać niezmienione po wymianie. Możliwość określania ważności opartej na modelu SSI może pomóc inżynierom w podejmowaniu decyzji dotyczących konserwacji, zaś proponowana metoda wymiany elementów systemu pozwala zwiększyć różnorodność części zamiennych poprzez znalezienie równoważnych elementów
Pulmonary cryptococcosis closely mimicking lung cancer in a membranous nephropathy patient taking calcineurin inhibitor
In patients with membranous nephropathy (MN), malignancy may be either the underlying disease or results of immunosuppressive therapy which may also lead to opportunistic infections including the pulmonary cryptococcosis. On CT scan, nodule is the most common feature in pulmonary cryptococcosis and it can mimic lung cancer both clinically and radiologically. Therefore, pulmonary nodular lesions caused by cryptococcosis may be easily misdiagnosed and require unnecessary surgical treatment. As such, we herein presented an isolated subpleural solitary nodule with satellite lesion that closely mimicked lung cancer on both contrast-enhanced computed tomography (CT) scan and 18F-fluorodeoxyglucose positron emission tomography (FDG-PET)/CT in an MN patient under long-term tacrolimus regimen. Cryptococcosis was ascertained by the finding of oval thick-walled yeast on histopathology of the lung biopsy specimen taken during the Argon-Helium cryotherapy. Further, the pulmonary lesions progressively dissipated after antifungal treatment. Arguably, our experience may help clinicians in general and nephrologists in particular with a better understanding of the cryptococcal infection manifesting as pulmonary nodule(s) in the MN patients and contribute to more efficacious differential diagnosis against the lung cancer
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