Publications by authors named "Juan A Tamayo-Ramos"

Despite the wide application of graphene-based materials, the information of the toxicity associated to some specific derivatives such as aminated graphene oxide is scarce. Likewise, most of these studies analyse the pristine materials, while the available data regarding the harmful effects of degraded forms is very limited. In this work, the toxicity of graphene oxide (GO), aminated graphene oxide (GO-NH), and their respective degraded forms (dGO and dGO-NH) obtained after being submitted to high-intensity sonication was evaluated applying in vitro assays in different models of human exposure.

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The development of novel advanced nanomaterials (NMs) with outstanding characteristics for their use in distinct applications needs to be accompanied by the generation of knowledge on their potential toxicological impact, in particular, that derived from different occupational risk exposure routes, such as inhalation, ingestion, and skin contact. The harmful effects of novel graphene-metal oxide composites on human health are not well understood, many toxicological properties have not been investigated yet. The present study has evaluated several toxicological effects associated with graphene decorated with manganese oxide nanoparticles (GNA15), in a comparative assessment with those induced by simple graphene (G2), on human models representing inhalation (A549 cell line), ingestion (HT29 cell line) and dermal routes (3D reconstructed skin).

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Viologen-derivatives are the most widely used redox organic molecules for neutral pH negative electrolyte of redox flow batteries. However, the long-established toxicity of the herbicide methyl-viologen raises concern for deployment of viologen-derivatives at large scale in flow batteries. Herein, we demonstrate the radically different cytotoxicity and toxicology of a series of viologen-derivatives in in vitro assays using model organisms representative of human and environmental exposure, namely human lung carcinoma epithelial cell line (A549) and the yeast Saccharomyces cerevisiae.

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is a robust microbial cell factory for organic acid production. However, the regulation of many industrially important pathways is still poorly understood. The regulation of the glucose oxidase (Gox) expression system, involved in the biosynthesis of gluconic acid, has recently been uncovered.

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The initial stages of the pandemic caused by SARS-CoV-2 showed that early detection of the virus in a simple way is the best tool until the development of vaccines. Many different tests are invasive or need the patient to cough up or even drag a sample of mucus from the throat area. Besides, the manufacturing time has proven insufficient in pandemic conditions since they were out of stock in many countries.

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The study of the biological response of microbial cells interacting with natural and synthetic interfaces has acquired a new dimension with the development and constant progress of advanced omics technologies. New methods allow the isolation and analysis of nucleic acids, proteins and metabolites from complex samples, of interest in diverse research areas, such as materials sciences, biomedical sciences, forensic sciences, biotechnology and archeology, among others. The study of the bacterial recognition and response to surface contact or the diagnosis and evolution of ancient pathogens contained in archeological tissues require, in many cases, the availability of specialized methods and tools.

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In the present study, a comparative human toxicity assessment between newly developed MnO nanoparticles with enhanced electrochemical properties (GNA35) and their precursor material (MnO) was performed, employing different in vitro cellular models representing main exposure routes (inhalation, intestinal and dermal contact), namely the human alveolar carcinoma epithelial cell line (A549), the human colorectal adenocarcinoma cell line (HT29), and the reconstructed 3D human epidermal model EpiDerm. The obtained results showed that MnO and GNA35 harbour similar morphological characteristics, whereas differences were observed in relation to their surface area and electrochemical properties. In regard to their toxicological properties, both nanomaterials induced ROS in the A549 and HT29 cell lines, while cell viability reduction was only observed in the A549 cells.

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The biological effects induced by the pollutants present in soils, together with the chemical and physical characterizations, are good indicators to provide a general overview of their quality. However, the existence of studies where the toxicity associated to soils contaminated with mixtures of pollutants applying both in vitro and in vivo models are scarce. In this work, three soils (namely, Soil 001, Soil 002 and Soil 013) polluted with different concentrations of hydrocarbons and heavy metals were evaluated using different organisms representative of human (HepG2 human cell line) and environmental exposure (the yeast Saccharomyces cerevisiae, the Gram-negative bacterium Pseudomonas putida and, for the in vivo evaluation, the annelid Enchytraeus crypticus).

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In the present work, the operational conditions for improving the degradation rates of Total Petroleum Hydrocarbons (TPHs) in contaminated soil from a machinery park were optimized at a microcosms scale along a 90-days incubation period. In this study, bioremediation strategies and an organic amendment have been tested to verify the remediation of soil contaminated with different hydrocarbons, mineral oils, and heavy metals. Specifically, designed biostimulation and bioaugmentation strategies were compared with and without adding vermicompost.

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Article Synopsis
  • Lithium silicates, especially lithium orthosilicate (LiSiO), are being explored as effective sorbents for capturing CO at high temperatures (450-700 °C), with LiSiO having the potential to adsorb significant amounts of CO.
  • The study investigates the structural, electronic, and thermodynamic properties of LiSiO and a binary eutectic mixture (LiNaSiO) using advanced theoretical methods, revealing strong CO adsorption through chemisorption.
  • Results indicate that CO significantly alters both the chemical structure of the gas and the characteristics of the lithium silicate surfaces, suggesting that these materials are promising candidates for CO capture across a wide range of temperatures.
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The development of new candidate alloys with outstanding characteristics for their use in the aeronautical field is one of the main priorities for the sector. In this context, nanocrystaline (nc) alloys are considered relevant materials due to their special features, such as their exceptional physical and mechanical properties. However, another important point that needs to be considered with newly developed alloys is the potential toxicological impact that these materials may have in humans and other living organisms.

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Carbon nanotubes (CNTs) have attracted the attention of academy and industry due to their potential applications, being currently produced and commercialized at a mass scale, but their possible impact on different biological systems remains unclear. In the present work, an assessment to understand the toxicity of commercial pristine multi-walled carbon nanotubes (MWCNTs) on the unicellular fungal model is presented. Firstly, the nanomaterial was physico-chemically characterized, to obtain insights concerning its morphological features and elemental composition.

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The current study was dedicated to finding the effect of soil amendments (biochar and compost) on plants belonging to Poaceae and Fabaceae families. Plants selected for the phytoremediation experiment included wheat (Triticum aestivum), maize (Zea mays), white clover (Trifolium repens), alfalfa (Medicago sativa), and ryegrass (Lolium multiflorum). The physiological and microbial parameters of plants and soil were affected negatively by the 4 % TPHs soil contamination.

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Due to the ever-increasing limitations of the use of lead-based materials, the manufacturing of lead-free piezoceramics with competitive piezoelectric properties and established nontoxicity is considered a priority for the scientific and industrial community. In this work, a lead-free system based on sodium potassium niobate (KNN), opportunely modified with MgNbO (MN), was prepared through a combination of a mechanochemical activation method and air sintering, and its toxicity was evaluated. The effect of the mechanical processing on the microstructure refinement of the processed powders was established by X-ray diffraction and the average crystallite size content of the NbO species was evaluated.

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Due to their exceptional physico-chemical and magnetic characteristics, rare earth (RE) permanent magnets are applied in multiple critical technologies. However, several environmental and economic difficulties arising from obtaining RE elements have prompted the search of alternatives with acceptable magnetic properties but containing a lower percentage of these elements in their composition. The aim of this work was to perform a preliminary toxicological evaluation of three forms of newly developed RE-lean alloys (one NdFeTi and two NdFeSi alloys) applying different in vitro assays, using as a benchmark a commercial NdFeB alloy.

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is the major industrial citrate producer worldwide. Export as well as uptake of citric acid are believed to occur by active, proton-dependent, symport systems. Both are major bottlenecks for industrial citrate production.

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The utilization of tungsten disulfide (WS) nanomaterials in distinct applications is raising due to their unique physico-chemical properties, such as low friction coefficient and high strength, which highlights the necessity to study their potential toxicological effects, due to the potential increase of environmental and human exposure. The aim of this work was to analyze commercially available aqueous dispersions of monolayer tungsten disulfide (2D WS) nanomaterials with distinct lateral size employing a portfolio of physico-chemical and toxicological evaluations. The structure and stoichiometry of monolayer tungsten disulfide (WS-ACS-M) and nano size monolayer tungsten disulfide (WS-ACS-N) was analyzed by Raman spectroscopy, whereas a more quantitative approach to study the nature of formed oxidized species was undertaken employing X-ray photoelectron spectroscopy.

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Boron nitride (BN) nanomaterials have been increasingly explored for potential applications in chemistry and biology fields (e.g., biomedical, pharmaceutical, and energy industries) due to their unique physico-chemical properties.

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Due to economic, environmental and geopolitical issues, the development of permanent magnets with a composition free of rare earth elements and with acceptable magnetic properties has been considered a priority by the international community, being MnAl based alloys amongst the most promising candidates. The aim of this work was to evaluate the toxicity of powders of two forms of newly developed MnAl(C) permanent magnets through exposure experiments applying three model organisms, using as a benchmark powders of a commercial rare-earth-containing magnet (NdFeB). For this purpose, the direct exposure to the different particles suspensions as well as to magnets leachates was evaluated.

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Article Synopsis
  • Graphene oxide is a promising nanomaterial with various applications, but its effects on biological systems, particularly in fungi, are not well understood.
  • Researchers optimized an RNA purification process to study the toxicity of different graphene oxide products on yeast, ensuring proper nucleic acid quality.
  • The study found that both forms of graphene oxide altered the expression of a significant number of genes related to stress responses and metabolism, with notable differences in gene expression patterns between the two types of graphene oxide tested.
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The physicochemical properties and the toxicological potential of commercially available MoS nanoparticles with different lateral size and degradation stage were studied in the present research work. To achieve this, the structure and stoichiometry of fresh and old aqueous suspensions of micro-MoS and nano-MoS was analyzed by Raman, while x-ray photoelectron spectroscopy allowed to identify more quantitatively the nature of the formed oxidized species. A, the toxicological impact of the nanomaterials under analysis was studied using adenocarcinomic human alveolar basal epithelial cells (A549 cells) and the unicellular fungus S.

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Graphene nanomaterials have attracted a great interest during the last years for different applications, but their possible impact on different biological systems remains unclear. Here, an assessment to understand the toxicity of commercial polycarboxylate functionalized graphene nanoplatelets (GN) on the unicellular fungal model Saccharomyces cerevisiae was performed. While cell proliferation was not negatively affected even in the presence of 800 mg L of the nanomaterial for 24 hours, oxidative stress was induced at a lower concentration (160 mg L), after short exposure periods (2 and 4 hours).

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The ability of commercial monolayer graphene oxide (GO) and graphene oxide nanocolloids (GOC) to interact with different unicellular systems and biomolecules was studied by analyzing the response of human alveolar carcinoma epithelial cells, the yeast and the bacteria to the presence of different nanoparticle concentrations, and by studying the binding affinity of different microbial enzymes, like the α-l-rhamnosidase enzyme RhaB1 from the bacteria and the AbG β-d-glucosidase from sp. (strain ATCC 21400). An analysis of cytotoxicity on human epithelial cell line A549, (colony forming units, ROS induction, genotoxicity) and (luminescence inhibition) cells determined the potential of both nanoparticle types to damage the selected unicellular systems.

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Currently, there is no consensus regarding the mechanism underlying Aspergillus niger citrate biosynthesis and secretion. We hypothesise that depending on the experimental setup, extracellular citrate accumulation can have fundamentally different underlying transcriptomic landscapes. We show that varying the amount and type of supplement of an arginine auxotrophic A.

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is an industrially important source for gluconic acid and glucose oxidase (GOx), a secreted commercially important flavoprotein which catalyses the oxidation of β-D-glucose by molecular oxygen to D-glucolactone and hydrogen peroxide. Expression of , the GOx encoding gene and the concomitant two step conversion of glucose to gluconic acid requires oxygen and the presence of significant amounts of glucose in the medium and is optimally induced at pH 5.5.

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