Inhibitors of Corrosion Induced by Sulfate-Reducing Bacteria

Currently, a lot of researcher’s attention is devoted to the problem of microbiologically influenced corrosion (MIC), since it causes huge damages to the economy, initiating the destruction of oil and gas pipelines and other underground constructions. To protect industrial materials from MIC effects an organic chemical inhibitors are massively used. However, the problem of their use is associated with toxicity, dangerous for the environment that caused the need for development the alternative methods of MIC repression. At the review, the data about different types of inhibitors-biocides usage has provided. The chemical inhibitors features are given and the mechanisms of their protective action are considered. The screening results and use of alternative and eco-friendly methods for managing the effect of corrosion caused by sulfate-reducing bacteria (SRB) are highlighted. Methods of joint application of chemical inhibitors and enhancers, such as chelators, biosurfactants, which contribute to reducing the concentration of chemical inhibitors, are discussed. The possibility of disruption of the quorum sensing interaction in the bacterial community to prevent the biofilm formation is considered. The information about the use of natural plant extracts, food waste, as well as by-products of agro-industrial production to combat MIC is provided. The development of biological corrosion control methods (to combat MIC) is of great importance for creating the best alternative and eco-friendly approaches to managing the effect of corrosion caused by SRB. The analysis of the literature data indicates the need to find the best alternatives and environmentally friendly solutions.

Novel In-Line Inspection Tool for Deposit Characterization in Pipelines

Deposition formation inside pipelines is a major and growing problem in the oil and gas industry. The optimal use of prevention and remediation tools such as chemical inhibitors and cleaning processes could lead to major savings due to minimized production problems and optimized pipe cleaning costs. This requires characterization and quantification of the actual deposits inside pipelines and downholes. Recently, a novel deposition inline inspection sensor moving inside the pipeline has been proposed based on "inside-out" electrical tomography. In this sensor, the distribution of electrical properties between the sensor and the pipe wall are estimated based on measurements carried out using electrodes around the sensor. In this study, the next generation sensor moving inside the pipeline is described and a deep neural network based approach to deposit estimation is introduced. Test results from a 70 m long semi-industrial scale flow loop containing paraffin wax and calcium carbonate deposits of different thicknesses are shown. Challenges include the changing position and orientation of the sensor during the low. The results show that the sensor is able to measure both deposit thickness and type with good accuracy which indicates that the sensor is suitable for industrial use. Accurate knowledge about deposits allows future blockage prevention, detecting build-up locations in the early phase, increasing accuracy of multi-phase flow and deposition models, optimization of chemical use and validation of deposit cleaning tools before integrity campaigns leading to overall reduced pipeline operation costs.

Histone acetylation regulates the expression of genes involved in worker reproduction in the ant Temnothorax rugatulus

Background In insect societies, queens monopolize reproduction while workers perform tasks such as brood care or foraging. Queen loss leads to ovary development and lifespan extension in workers of many ant species. However, the underlying molecular mechanisms of this phenotypic plasticity remain unclear. Recent studies highlight the importance of epigenetics in regulating plastic traits in social insects. Thus, we investigated the role of histone acetylation in regulating worker reproduction in the ant Temnothorax rugatulus. We removed queens from their colonies to induce worker fecundity, and either fed workers with chemical inhibitors of histone acetylation (C646), deacetylation (TSA), or the solvent (DMSO) as control. We monitored worker number for six weeks after which we assessed ovary development and sequenced fat body mRNA. Results Workers survived better in queenless colonies. They also developed their ovaries after queen removal in control colonies as expected, but not in colonies treated with the chemical inhibitors. Both inhibitors affected gene expression, although the inhibition of histone acetylation using C646 altered the expression of more genes with immunity, fecundity, and longevity functionalities. Interestingly, these C646-treated workers shared many upregulated genes with infertile workers from queenright colonies. We also identified one gene with antioxidant properties commonly downregulated in infertile workers from queenright colonies and both C646 and TSA-treated workers from queenless colonies. Conclusion Our results suggest that histone acetylation is involved in the molecular regulation of worker reproduction, and thus point to an important role of histone modifications in modulating phenotypic plasticity of life history traits in social insects.

PI3K/AKT/mTOR Signaling Pathway Is Required for JCPyV Infection in Primary Astrocytes

Astrocytes are a main target of JC polyomavirus (JCPyV) in the central nervous system (CNS), where the destruction of these cells, along with oligodendrocytes, leads to the fatal disease progressive multifocal leukoencephalopathy (PML). There is no cure currently available for PML, so it is essential to discover antivirals for this aggressive disease. Additionally, the lack of a tractable in vivo models for studying JCPyV infection makes primary cells an accurate alternative for elucidating mechanisms of viral infection in the CNS. This research to better understand the signaling pathways activated in response to JCPyV infection reveals and establishes the importance of the PI3K/AKT/mTOR signaling pathway in JCPyV infection in primary human astrocytes compared to transformed cell lines. Using RNA sequencing and chemical inhibitors to target PI3K, AKT, and mTOR, we have demonstrated the importance of this signaling pathway in JCPyV infection of primary astrocytes not observed in transformed cells. Collectively, these findings illuminate the potential for repurposing drugs that are involved with inhibition of the PI3K/AKT/mTOR signaling pathway and cancer treatment as potential therapeutics for PML, caused by this neuroinvasive virus.

Chemical inhibition of pathological reactive astrocytes promotes neural protection

Disease, injury, and aging induce reactive astrocyte states with pathological functions. In neurodegenerative diseases, inflammatory reactive astrocytes are abundant and contribute to progressive cell loss. Modulating the state or function of these reactive astrocytes thereby represents an attractive therapeutic goal. Leveraging a cellular phenotypic screening platform, we show that chemical inhibitors of HDAC3 effectively block pathological astrocyte reactivity. Inhibition of HDAC3 reduces molecular and functional features of reactive astrocytes in vitro including inflammatory gene expression, cytokine secretion, and antigen presentation. Transcriptional and chromatin mapping studies show that HDAC3 inhibition mediates a switch between pro-inflammatory and anti-inflammatory states, which disarms the pathological functions of reactive astrocytes. Systemic administration of a blood-brain barrier penetrant chemical inhibitor of HDAC3, RGFP966, blocks reactive astrocyte formation and promotes axonal protection in vivo. Collectively, these results establish a platform for discovering chemical modulators of reactive astrocyte states, inform the mechanisms controlling astrocyte reactivity, and demonstrate the therapeutic potential of modulating astrocyte reactivity for neurodegenerative diseases.

Inhibiting wax deposition using palm oil additives

Among the flow assurance problems that the petroleum industry faces, the deposition of paraffin waxes on to the wall of the pipeline is the most challenging. The challenge arises when the crude oil temperature decreases below the wax appearance temperature which prompts wax crystallization in the crude oil. An efficient method in remedying paraffin wax deposition is the utilization of chemical inhibitors. However, currently used chemical inhibitors are costly and environmentally harmful if a spillage occurs. Therefore, the use of biodegradable or environmentally friendly inhibitors as potential chemical inhibitors is being studied by various researchers. This study investigated oleic acid, poly (ethylene-co-vinyl acetate) (EVA) and triethanolamine (TEA) as inhibitors that perform based on the van der Waals intermolecular interaction between the main wax component molecule eicosane C20H42 using molecular dynamics simulations Material Studio 8.0 software package. In order to analyse the desired structural property which is the radial distribution function (RDF), COMPASS force field was used. The RDF and g(r) function portrayed the functional atoms which aid in inhibiting the agglomeration and crystallization of the wax crystal formation. The presence of a carbonyl oxygen in oleic acid plays a vital role to inhibit the wax formation through the van der Waals interaction between active hydrogen atoms in eicosane molecule. Therefore, the chances of wax inhibition in eicosane are higher by introducing oleic acid as an inhibitor as compared to EVA and TEA. The results were then validated experimentally utilizing a cold finger technique under static condition.

Sewage Sludge as Inhibitor of the Formation of Persistent Organic Pollutants during Incineration

With the objective of suppressing dioxins and furans (PCDD/Fs) emission in municipal solid waste incineration plants (MSWI), different chemical inhibitors have been tested. Among these inhibitors, nitrogen and sulphur compounds can significantly suppress PCDD/Fs formation via de novo synthesis, which gives very interesting results with very little capital investment. In recent years, the possibility of using waste rich in nitrogen and/or sulphur as a source of inhibitor compounds has been considered, and thus has reduced the emissions of pollutants while the waste is treated. The effect of adding sludge from urban sewage treatment plants in three variants has been specially studied: directly mixing the waste, using the decomposition gas of the previously dried sludge, and using the decomposition gas of the sludge together with other inhibitors such as thiourea. Reduction of emissions in laboratory tests using model samples indicated the efficiency to be higher than 99%, using sewage sludge (SS) as an inhibitor whereas, in actual MSWI plants, the efficiency can be as high as 90%.