1,913 research outputs found

    Aplicaci贸n de t茅cnicas microbiol贸gicas y qu铆micas para la recuperaci贸n de suelos contaminados por plaguicidas e hidrocarburos arom谩ticos polic铆clicos. Evaluaci贸n de su viabilidad mediante estudios de biolog铆a molecular y ecotoxicidad

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    En la actualidad existe un inter茅s creciente por los m茅todos de recuperaci贸n biol贸gicos de suelos contaminados, present谩ndose la biorrecuperaci贸n como una alternativa a los m茅todos convencionales (landfilling, incineraci贸n o descomposici贸n qu铆mica). Se trata de una herramienta respetuosa con el medio ambiente, de bajo coste y no invasiva, que utiliza organismos vivos para detoxificar las sustancias de riesgo para el hombre y el medio ambiente. Por este motivo, en este estudio para conseguir la recuperaci贸n de suelos contaminados se han llevado a cabo ensayos de biodegradaci贸n y mineralizaci贸n en medio acuoso, en suspensiones suelo-agua y en suelo. Los contaminantes org谩nicos estudiados en este trabajo fueron: cinco herbicidas pertenecientes a la familia qu铆mica de las fenilureas (diur贸n, linur贸n, isoprotur贸n, clortolur贸n y fluometur贸n), otro herbicida de la familia de las dinitroanilinas (trifluralina), un insecticida organofosforado (clorpirif贸s), as铆 como hidrocarburos arom谩ticos polic铆clicos (PAHs) de bajo y alto peso molecular. Cuando la biodegradaci贸n no se puede llevar a cabo de forma natural debido a que los microorganismos no disponen de los nutrientes esenciales para ello en la zona contaminada, o no presentan las herramientas metab贸licas necesarias para actuar sobre un determinado contaminante, se requiere de la intervenci贸n mediante actuaciones encaminadas a fomentar la actividad microbiol贸gica, siendo necesario recurrir a la biodegradaci贸n asistida a trav茅s del empleo de dos posibles t茅cnicas: bioest铆mulo (mediante la adici贸n de nutrientes) y bioaumento (inoculando microorganismos de origen end贸geno y/o ex贸geno). Los macro y micronutrientes necesarios para el desarrollo bacteriano suelen estar presentes en el suelo en cantidades demasiado bajas, provocando una limitaci贸n para la actividad microbiana, de ah铆 la necesidad de emplear una soluci贸n de nutrientes que act煤e como estimulante de los microorganismos degradadores presentes en el suelo. Los microrganismos usados como degradadores espec铆ficos se obtienen mediante cultivos de enriquecimiento de suelos que han estado en contacto con el contaminante durante un largo periodo de tiempo. La microbiota del suelo se expone a una elevada concentraci贸n de contaminante, facilitando de esta forma el crecimiento de aquellos microorganismos que presentan la capacidad de usar como fuente de carbono y energ铆a al contaminante org谩nico en cuesti贸n. Los procesos de recuperaci贸n de suelos contaminados por compuestos org谩nicos como plaguicidas y PAHs est谩n a menudo muy limitados a consecuencia de sus propiedades f铆sicoqu铆micas, baja solubilidad, elevado kow y koc, estructura arom谩tica, grupos halogenados, etc. Estas propiedades hacen que la fracci贸n biodisponible del contaminante en el suelo sea muy baja y, por lo tanto, sean sustancias recalcitrantes mostrando una elevada persistencia. Con el fin de mejorarla, en el presente estudio se han empleado ciclodextrinas, oligosac谩ridos c铆clicos que, gracias a su capacidad para formar complejos de inclusi贸n con compuestos org谩nicos hidrof贸bicos, son capaces de incrementar su solubilidad en agua y en consecuencia su biodisponibilidad. El descenso de la concentraci贸n inicial del contaminante no implica la no formaci贸n y acumulaci贸n de metabolitos t贸xicos, lo que har铆a replantear la aplicaci贸n o no de una determinada t茅cnica de biorrecuperaci贸n. Por lo que, ensayos de ecotoxicidad han sido realizados al inicio y al final de los tratamientos aplicados en el presente trabajo, mediante la monitorizaci贸n de la bioluminiscencia natural de la bacteria Vibrio fisheri (Microtox庐), con el fin de evaluar la eficacia y seguridad de la estrategia de descontaminaci贸n empleada y por lo tanto su viabilidad. Los estudios de biolog铆a molecular llevados a cabo han ayudado igualmente, a evaluar la viabilidad de las t茅cnicas de biorrecuperaci贸n empleadas. Gracias al empleo de distintas t茅cnicas de biolog铆a molecular se ha conseguido, por un lado, identificar las cepas bacterianas aisladas y seleccionadas como degradadoras de los distintos contaminantes org谩nicos estudiados mediante la secuenciaci贸n del ARN ribos贸mico 16S, y por otro lado, secuenciar el genoma de la cepa bacteriana seleccionada y describir la ruta de degradaci贸n de fenantreno que utiliza, gracias a la identificaci贸n de los metabolitos formados y de los genes que codifican las enzimas responsables de llevar a cabo la ruta de degradaci贸n, mediante una amplia b煤squeda bibliogr谩fica y un an谩lisis exhaustivo de la anotaci贸n del genoma bacteriano empleando diversas bases de datos. Para la confirmaci贸n de la presencia de estos genes degradadores en el genoma bacteriano, se emplearon herramientas bioinform谩ticas (BLAST, Clustal Omega, etc.) que nos permitieron alinear la secuencia del gen con el genoma de la cepa bacteriana estudiada (Stenotrophomonas maltophilia CPHE1), confirmando la posibilidad de la presencia de dicho gen en la bacteria de estudio. Por 煤ltimo, una vez identificados los genes implicados, se estudi贸 su expresi贸n empleando la Reacci贸n en Cadena de la Polimerasa Reversa (RT-PCR), confirmando as铆 la posible ruta de degradaci贸n propuesta.Nowadays, there is a growing interest in using biological remediation methods to recuperate polluted soils, being bioremediation an alternative to conventional methods (landfilling, incineration or chemical decomposition). It is an environmentally friendly, low-cost, noninvasive tool that uses living organisms to detoxify substances which pose a risk for humans and the environment. For this reason, in this study biodegradation and mineralization assays in aqueous medium, soil-water suspensions and soil have been carried out to achieve the bioremediation of contaminated soils. The organic contaminants studied in this work were: five herbicides belonging to the chemical family of phenylureas (diuron, linuron, isoproturon, chlorotoluron and fluometuron), one herbicide belonging to the dinitroaniline family (trifluralin), an organophosphate insecticide (chlorpyrifos) and low- and high molecular weight polycyclic aromatic hydrocarbons (PAHs). When biodegradation of a pollutant cannot occur naturally because microorganisms do not have the essential nutrients for it in the contaminated area, or do not have the necessary metabolic tools to act on a particular pollutant, intervention is required through actions designed to promote microbiological activity, assisting the biodegradation process through the use of two different techniques: biostimulation (by adding nutrients) and bioaugmentation (inoculating endogenous and/or exogenous microorganisms). The macro and micronutrients needed for bacterial development are usually present in soil in very small amounts, causing a limitation for microbial activity, and therefore, it is essential the use of a nutrient solution that acts as stimulant for the degrading microorganisms present in soil. Microorganisms used as specific degraders are isolated through enrichment cultures using soils that have been in contact with the pollutant for a long period of time. Soil microbiota is exposed to a high concentration of contaminants, thus facilitating the growth of those microorganisms that present the ability to use the organic pollutant in question as source of carbon and energy. Recuperation processes of soils contaminated by organic compounds such as pesticides and PAHs are often very limited due to their physical-chemical properties, low solubility, high kow and koc, aromatic structure, halogenated groups, etc. These properties together make the bioavailable fraction of the contaminant in the soil very low, leading to the production of recalcitrant substances which show high persistence. In order to improve it, cyclodextrins have been used in this study since they are cyclic oligosaccharides with the ability to form inclusion complexes with hydrophobic organic compounds, being able to increase their solubility in water and consequently their bioavailability. The decreasing of the initial contaminant concentration does not involve the no formation or accumulation of toxic metabolites, what would make to reconsider the application or not of a particular bioremediation technique. Ecotoxicity tests have been carried out at the beginning and at the end of the treatments applied in this work, by monitoring the natural bioluminescence of the bacterium Vibrio fisheri (Microtox庐), in order to evaluate the efficacy and safety of the decontamination strategy used and hence, its viability. Molecular biological studies have also helped to assess the feasibility of the bioremediation techniques employed. As a result of using different molecular biological techniques, it has been possible, on the one hand, to identify the bacterial strains isolated and selected as specific degraders for the studied pollutants by sequencing the ribosome RNA 16S, and on the other hand, to sequence the genome of the selected bacterial strain and describe the phenantrene degradation pathway used, thanks to the identification of the metabolites formed and the genes that encode the enzymes responsible for the degradation route, through an extensive bibliographic search and the analysis of bacterial genome annotation using various databases. For confirmation of the presence of these degrading genes in the bacterial genome, bioinformatics tools (BLAST, Clustal Omega, etc.) were employed to allow us to align the gene sequence with the studied genome (Stenotrophomonas maltophilia CPHE1), validating the possibility of the presence of such gene in the bacteria studied. Finally, once the genes involved were identified, their expression was studied using the Reverse Polymerase Chain Reaction (RT-PCR), thus confirming the possible proposed biodegradation pathway

    Photocatalysis in the Wastewater Treatment

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    The use of photocatalysis for wastewater treatment is an important area of research, which is not yet fully exploited at an industrial level and has significant potential in the disposal of many industrial effluents, particularly the effluents that are difficult to treat by conventional treatment processes. This reprint tries to know the latest advances in the field of wastewater treatment by photocatalysis. In this sense, it is worth mentioning the treatments based on photolysis, TiO2/solar light, oxidants/ultraviolet irradiation, oxidants/catalyst/ultraviolet irradiation, etc. In addition, the reprint describes catalyst manufacturing methods and reaction mechanisms

    Protecting public health and the environment: towards a general ban on cellulose acetate cigarette filters in the European Union

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    After the establishment of a causal relationship between tobacco use and cancer in the 1950s, cellulose acetate filters were introduced with the claim to reduce the adverse health impact of unfiltered cigarettes. Often perceived to be more pleasant and healthy, filters encouraged smoking. However, filtered cigarettes are more deeply inhaled to obtain the same nicotine demand while altered combustion releases more tobacco-specific nitrosamines. The increasing use of cigarette filter ventilation is associated with a sharp rise in lung adenocarcinomas in recent decades. While not preventing adverse health effects, a global environmental problem has been created due to the non-biodegradable filter litter, causing ecotoxicological effects and the spread of microplastics. Recently, the Belgian Superior Health Council advised policymakers to ban cigarette filters as single-use plastics at both national and European levels. This article outlines the arguments used to justify this plea (human health and environment), the expected effects of a filter ban, as well as the public reception and reactions of the tobacco industry. The specific context of the European Union is discussed including the revision of the Single-Use Plastics Directive, affording a new opportunity to ban plastic filters. This perspective article aims to fuel the momentum and cooperation among member states for this purpose

    Eco-Friendly Engineered Nanomaterials Coupled with Filtering Fine-Mesh Net as a Promising Tool to Remediate Contaminated Freshwater Sludges: An Ecotoxicity Investigation

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    The use of eco-friendly engineered nanomaterials represents a recent solution for an effective and safe treatment of contaminated dredging sludge. In this study, an eco-designed engineered material based on cross-linked nanocellulose (CNS) was applied for the first time to decontaminate a real matrix from heavy metals (namely Zn, Ni, Cu, and Fe) and other undesired elements (mainly Ba and As) in a lab-scale study, with the aim to design a safe solution for the remediation of contaminated matrices. Contaminated freshwater sludge was treated with CNS coupled with a filtering fine-mesh net, and the obtained waters were tested for acute and sublethal toxicity. In order to check the safety of the proposed treatment system, toxicity tests were conducted by exposing the bacterium Aliivibrio fischeri and the crustacean Heterocypris incongruens, while subtoxicity biomarkers such as lysosomal membrane stability, genetic, and chromosomal damage assessment were performed on the freshwater bivalve Dreissena polymorpha. Dredging sludge was found to be genotoxic, and such genotoxicity was mitigated by the combined use of CNS and a filtering fine-mesh net. Chemical analyses confirmed the results by highlighting the abetment of target contaminants, indicating the present model as a promising tool in freshwater sludge nanoremediation

    The Different Faces of Ibuprofen-Based Ionic Liquids and Eutectic Systems: Promising Innovative Ionic-Liquid-Based Formulations of an Over-the-Counter Anti-Inflammatory Drug

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    The global goal of the current thesis is to demonstrate the feasibility of the ionic liquids (ILs) platform to boost 鈥渙ld鈥 drugs efficiency. With this ground, cholinium- and imidazolium- based ILs were used to formulate pharmaceutically active ILs (API-ILs) and eutectic systems with ibuprofen (Ibu) as parent active pharmaceutical ingredient (API). The aqueous solubility, water and simulated biological fluids, of the IBU-based ILs and eutectics relatively to Ibu neutral and salt form (sodium ibuprofen) were assessed. Jointly, insights into task-specific fluorinated ILs that reduce the impact of the addition of water upon the IL鈥檚 H-bond acceptance ability, a key factor to obtain functionalized materials to be used in the dissolution of drugs or biomolecules, were attained. The cytotoxic profiles were characterized for both IBU-based ILs and eutectics, as well as for the parent API (Ibu), using two human cells lines, colon carcinoma cells (Caco-2) and hepatocellular carcinoma cells (HepG-2). The biocompatibility of all Ibu formulations was also evaluated through a hemolytic activity assay. Moreover, the anti-inflammatory properties of all Ibu formulations, ILs, eutectics, and parent API, were assessed through the inhibition of bovine serum albumin (BSA) denaturation and inhibition of cyclooxygenases (COX-1 and COX-2). The assessment of ionicity, through measurements of density, viscosity, and ionic conductivity, was carried out to evaluate the formation of ion-pairs or clusters that enhance membrane permeation. In the end, an in vitro skin permeation assay was attained through Skin Parallel Artificial Membrane Permeability Assays (Skin-PAMPA) to evaluate the Ibu-based ILs and eutectics skin permeability. The evaluation of the permeation potential allows to guide the design of transdermal drug delivery systems. The results of this thesis comprise a proof of concept for the feasibility of task-specific ILs and IL-based eutectics, namely API-ILs and API-based eutectics, in the development of novel drug delivery systems, and more broadly for biological, biochemical, and pharmaceutical applications.O objetivo global da presente tese 茅 demonstrar a viabilidade do uso da plataforma de l铆quidos i贸nicos (LIs) para aumentar a efici锚ncia de f谩rmacos 鈥渁ntigos鈥. Desta forma, LIs 脿 base de col铆nio e imidaz贸lio foram usados para formular LIs farmacologicamente ativos (API- ILs) e sistemas eut茅cticos com ibuprofeno (Ibu) como princ铆pio ativo (API) de origem. A solubilidade aquosa, em 谩gua e em fluidos biol贸gicos simulados, dos LIs 脿 base de Ibu e eut茅cticos em rela莽茫o ao Ibu neutro e na forma de sal (ibuprofeno s贸dico) foi avaliada. Foram tamb茅m obtidas informa莽玫es sobre LIs fluorados que reduzem o impacto da adi莽茫o de 谩gua devido 脿 sua capacidade de aceita莽茫o de liga莽玫es de hidrog茅nio, um fator chave para se obter materiais funcionalizados para serem usados na dissolu莽茫o de f谩rmacos ou biomol茅culas. Os perfis citot贸xicos foram caracterizados tanto para ILs baseados em Ibu como para os sistemas eut茅cticos e o API de origem (Ibu), usando duas linhagens de c茅lulas humanas, c茅lulas de carcinoma de c贸lon (Caco-2) e c茅lulas de carcinoma hepatocelular (HepG-2). A biocompatibilidade de todas as formula莽玫es de Ibu tamb茅m foi avaliada atrav茅s de um ensaio de atividade hemol铆tica. As propriedades anti-inflamat贸rias de todas as formula莽玫es de Ibu, ILs, eut茅ticos e API de origem, foram avaliadas atrav茅s da inibi莽茫o da desnatura莽茫o da albumina s茅rica bovina (BSA) e inibi莽茫o das ciclooxigenases (COX-1 e COX-2). A avalia莽茫o da ionicidade atrav茅s da medi莽茫o de densidade, viscosidade e condutividade i贸nica, foi realizada para avaliar a forma莽茫o de pares i贸nicos ou aglomerados que poder茫o aumentar a permea莽茫o nas membranas. Por fim, foi realizado um ensaio de permea莽茫o cut芒nea in vitro atrav茅s do sistema Skin Parallel Artificial Membrane Permeability Assay (Skin-PAMPA) para avaliar a permeabilidade cut芒nea dos Lis e eut茅ticos 脿 base de Ibu. A avalia莽茫o do potencial de permea莽茫o permite orientar a correta formula莽茫o de um novo sistema de entrega transd茅rmica de f谩rmacos. Os resultados desta tese compreendem uma prova de conceito para a viabilidade do uso de LIs e eut茅cticos baseados em IL, nomeadamente API-ILs e eut茅cticos baseados em API, no desenvolvimento de novos sistemas de administra莽茫o de f谩rmacos e, mais amplamente, para aplica莽玫es biol贸gicas, bioqu铆micas e aplica莽玫es farmac锚uticas

    Photocatalytic processes as a potential solution for plastic waste management

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    Plastics have become a critical environmental problem due to their widespread use, high physico-chemical stability and the inefficiency of wastewater treatments. Despite the efforts to reduce production and to increase reuse and recycling, the current strategies for plastic waste treatment are not suitable to handle with the growing demand of plastics and the concomitant waste in an environmentally friendly manner. Herein, we review the existing strategies for the treatment of plastic waste, highlighting photocatalytic processes as a potential solution for the degradation of plastics. The possibility of incorporating photocatalysts to plastics during the production process could enhance their light-activated biodegradability. Parallelly, photocatalysts can be employed during waste treatment processes of non-biodegradable stable plastics. The scarcely studied factors affecting plastic photocatalytic degradation, namely catalyst type, reactor configuration, and radiation source (intensity and wavelength), are discussed, highlighting the role that photocatalytic processes can play in the future of plastic management. Finally, relevant quantification methods for measuring the photo-degradation of plastics are overviewed. We believe that photocatalysis can be an environmentally friendly strategy both to increase the biodegradability of plastics and to treat plastic waste. With this novel comprehensive overview, we hope to stimulate further research and innovation in this field.Xunta de Galicia | Ref. ED481B 2019/091Universidade de Vigo/CISU

    Biocatalytic Applications in Biotechnology

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    At present, the increasing demand for novel biotechnological products is supported through the continuous development of biocatalytic applications. As a consequence, the progress of research regarding enzymatic catalysis in aqueous, non-aqueous, organic (polar or non-polar), and/or non-solvent media is decisive. Experimental design methods, which also may comprise in silico studies, the design of specific reactors and conditions, the reactions of significant chemical and/or biochemical processes that are relevant to industrial production, enzyme kinetic methods, the investigation of enzymatic mechanisms and the use of immobilized enzymes and/or microbial cells on various inert matrices, are all useful. A plethora of enzymes of several classes, which may potentially be used as biocatalysts in biotechnological applications, are available. Among these enzymes, the more common are oxidoreductases (laccase, catalase, glucose oxidase, etc.), hydrolases (amylases, lipases, proteases, amidases, cellulases, esterases, etc.), isomerases (epimerases, topoisomerases, mutases, etc.), and others. By means of the aforementioned biocatalysts and the utilization of specific biotechnological methods, important, cost-effective, sustainable, and environmentally friendly processes have been applied for the synthesis and/or the conversion of a huge number of market-required products

    Diatom motility and nuclear alterations are affected by sediment elutriates of agricultural streams

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    Diatoms respond to toxicants in lotic systems, and they are commonly considered to be sensitive indicators in environmental safety assessment. In addition to the structural characteristics of the algal populations, recent studies have shown that endpoints such as nuclear anomalies or diatom motility measures can be affected quickly by environmental changes. We sought to determine if cell density, cell size, nuclear anomalies and motility of the diatom Nitzschia palea were useful indicators of sediment quality from agricultural streams. For this purpose, we exposed cultures of the diatom to elutriates from sediments of a stream that flows through an intensive agricultural area, and measured the responses of the populations for 7 days in laboratory tests. The bioassays showed that motility measures in Nitzschia palea and the condition of their nuclear membranes rapidly reflected the effects of sediment quality after only 48 h of exposure; mean cell density and length were affected by day 7. The sediment elutriates affected cell movements by shortening the total path length and decreasing cell velocity; they also increased the number of cells with nuclear membrane breakage. Our results from these bioassays show that diatom motility measurements and the condition of the nuclei might be indicators that respond faster to impacts than the traditional structural parameters, such as cell density, specific composition of the assemblage or diversity metrics of the algal communities more often used in biomonitoring.Instituto de Limnolog铆a "Dr. Ra煤l A. Ringuelet

    Growth Performance of Mytilus galloprovincialis Lamarck, 1819 under an Innovative Integrated Multi-Trophic Aquaculture System (IMTA) in the Mar Grande of Taranto (Mediterranean Sea, Italy)

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    The cultivation of the Mediterranean mussel, Mytilus galloprovincialis Lamarck, 1819, has been tested in an innovative Integrated Multitrophic Aquaculture system (IMTA) in the Mar Grande of Taranto, as part of the EU-funded Remedialife project. This farming method could solve several problems including the low growth rate in mesotrophic environments while reducing the environmental impact of fish mariculture. Three productive cycles have been carried out. The first (2018鈥2019, traditional experiment) was conducted in three long lines around six cages of the fish farm in order to evaluate total mussel production under the innovative IMTA system and quality for human consumption by analyzing the concentration of culturable heterotrophic bacteria, total and fecal coliforms, Escherichia coli and Salmonella spp. in mussel tissues. In addition, 17 polycyclic aromatic hydrocarbons (PAHs), including 16 EPA priority compounds and seven polychlorinated biphenyls (PCBs), which are indicators of PCB contamination in the environment, were analyzed using gas chromatography in conjunction with a mass spectrometer. The second cycle (2020鈥2021, horizontal distance experiment) aimed to test the influence of fish cages on mussel growth by placing mussels near and far from the fish cages. The third cycle (2021鈥2022, vertical distance experiment) aimed to overcome the phenomenon of 鈥渉eat waves鈥 that can occur in the Mar Grande of Taranto during summer by testing the growth performance of mussels at two different depths (1 and 12 m). The following parameters were measured: Shell Length, L (mm); Shell Dry Weight, SDW (g); Flesh Dry Weight, FDW (g); Condition Index, IC = FDW/SDW. The results showed that the best growth performance was obtained near the fish cages and at a depth of 12 m. Moreover, the indicators of microbial contamination and concentrations of chemical compounds analyzed in mussel tissues cultured under the innovative IMTA system were in compliance with the reference values of European regulations

    Microplastics could be marginally more hazardous than natural suspended solids - A meta-analysis

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    Microplastics (MP) are perceived as a threat to aquatic ecosystems but bear many similarities to suspended sediments which are often considered less harmful. It is, therefore pertinent to determine if and to what extent MP are different from other particles occurring in aquatic ecosystems in terms of their adverse effects. We applied meta-regressions to toxicity data extracted from the literature and harmonized the data to construct Species Sensitivity Distributions (SSDs) for both types of particles. The results were largely inconclusive due to high uncertainty but the central tendencies of our estimates still indicate that MP could be marginally more hazardous compared to suspended sediments. In part, the high uncertainty stems from the general lack of comparable experimental studies and dose-dependent point estimates. We therefore argue that until more comparable data is presented, risk assessors should act precautionary and treat MP in the 1鈥1000 碌m size range as marginally more hazardous to aquatic organisms capable of ingesting such particles.publishedVersio
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