Produced water (PW) is the wastewater generated when water from underground reservoirs is brought to the surface during oil or gas extraction. PW is generated in large amounts and has a complex ...composition, containing various toxic organic and inorganic compounds. PW is currently treated in conventional trains that include phase separators, decanters, cyclones and coarse filters in order to comply with existing regulation for discharge. These treatment trains do not achieve more restrictive limitations related to the reuse of the effluent (reinjection into extraction wells) or other beneficial uses (e.g., irrigation). Therefore, and to prevent environmental pollution, further polishing processes need to be carried out. Characterization of the PW to determine major constituents is the first step to select the optimum treatment for PW, coupled with environmental factors, economic considerations, and local regulatory framework. This review tries to provide an overview of different treatments that are being applied to polish this type of effluents. These technologies include membranes, physical, biological, thermal or chemical treatments, where special emphasis has been made on advanced oxidation processes due to the advantages offered by these processes. Commercial treatments, based on the combination, modification and improvement of simpler treatments, were also discussed.
•Oil and gas sector is one of the eight most water intensive industries.•PW is generated when water from reservoirs is brought to surface in oil extraction.•Composition and final use of PW determines its treatment train.•Combination of treatments are necessary when there is a wide variety of components.•Minimization, disposal and reuse are options for PW.
The ultimate goal of this article is to highlight the relevance of heat conduction along the fine wires of a thermocouple, even if its junction presents a bead-like shape. In the thermocouple heat ...transfer balance, needed to derive the gas temperature from that of the sensor, the ‘choice’ between the correlations for convection to a sphere (because of that apparent shape) or a cylinder still generates considerable doubts. In this work, a 2-D, two-color pyrometer has been used to obtain temperature profiles along thermocouples with different bead/wire size ratios in conditions representative of combustion environments. The results prove that commercial beads (2–3 times larger than the wire) do not generate any gradient, and that a Nu(Re) correlation for a cylinder should be implemented, since the temperature in the junction is actually dominated by heat conduction from/to the adjacent wires, except for very large beads. Furthermore, some gradients found in the wires, around those large beads and elsewhere, have been compared with simple models that adequately reproduce their reach, considering both the conduction along the metal wires and convection from the gas. A criterion for neglecting heat conduction errors in thermocouple measurements is given, in general relaxing those commonly cited in the literature. However, the relevance of carefully considering this criterion is highlighted, for its implication in the gradients measurable in the gas and the spatial resolution attainable. These recommendations are extensible to other techniques based on thermocouples.
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•Tau interacts with Microtubule, Mitochondria, Nucleic Acids and Synapse.•Tau participates in Fats transport, β-Amyloid cascade and Proteostasis.•Tauopathies result from disruption of ...a complex array of interconnected interactions.•Phosphorylation and ATP homeostasis regulates all tau-partner interactions.
It is well established that neurodegenerative diseases known as tauopathies are characterized by the presence of filamentous forms of phosphorylated tau protein inside neurons. However, the causal relationship between the initial symptoms of a particular disease and the molecular events affecting tau and leading to the appearance of tangles of filamentous forms of this protein remains unknown. Even the main function (or functions) of tau inside neurons is debatable and controversial. Tau seems to be a multifunctional protein. I review here some of the most studied interactions of tau with different macromolecules and proteins, which can be classified according to the structural o functional unit within which the interaction works: Microtubule, Nuclear localization and DNA, Synaptic activity, RNA metabolism, Fats transport, Proteostasis, Amyloid Cascade Hypothesis, Mitochondria and Phosphorylation. Although this seems to be a broad spectrum of tau functions, interactome studies of tau reveal hundreds of plausible partners of tau, suggesting that it engages in an extensive network of interconnected regulatory interactions by means of its high capability to interact with all kinds of proteins and complex structures, combined with its vast number of post-translational modifications. I include also some thermodynamic data concerning the interaction of tau with some partners.
Abstract
Here we explore the impact of all major factors, such as the nonhomogeneous gas distribution, galactic rotation, and gravity, on the observational appearance of superbubbles in nearly ...face-on spiral galaxies. The results of our 3D numerical simulations are compared to the observed gas column density distribution in the largest southeast superbubble in the late-type spiral galaxy NGC 628. We make use of the star formation history inside the bubble derived from the resolved stellar population seen in Hubble Space Telescope images to obtain its energy and demonstrate that the results of numerical simulations are in good agreement with the observed gas surface density distribution. We also show that the observed gas column density distribution constrains the gaseous disk scale height and the midplane gas density if the energy input rate can be obtained from observations. This implies that observations of large holes in the interstellar gas distribution and their stellar populations have the potential power to solve the midplane gas density–gaseous disk scale height degeneracy problem in nearly face-on galaxies. The possible role of superbubbles in driving the secondary star formation in galaxies is also briefly discussed.
The increasing demand of analytical information related to inorganic engineered nanomaterials requires the adaptation of existing techniques and methods, or the development of new ones. The challenge ...for the analytical sciences has been to consider the nanoparticles as a new sort of analytes, involving both chemical (composition, mass and number concentration) and physical information (e.g. size, shape, aggregation). Moreover, information about the species derived from the nanoparticles themselves and their transformations must also be supplied. Whereas techniques commonly used for nanoparticle characterization, such as light scattering techniques, show serious limitations when applied to complex samples, other well-established techniques, like electron microscopy and atomic spectrometry, can provide useful information in most cases. Furthermore, separation techniques, including flow field flow fractionation, capillary electrophoresis and hydrodynamic chromatography, are moving to the nano domain, mostly hyphenated to inductively coupled plasma mass spectrometry as element specific detector. Emerging techniques based on the detection of single nanoparticles by using ICP-MS, but also coulometry, are in their way to gain a position. Chemical sensors selective to nanoparticles are in their early stages, but they are very promising considering their portability and simplicity. Although the field is in continuous evolution, at this moment it is moving from proofs-of-concept in simple matrices to methods dealing with matrices of higher complexity and relevant analyte concentrations. To achieve this goal, sample preparation methods are essential to manage such complex situations. Apart from size fractionation methods, matrix digestion, extraction and concentration methods capable of preserving the nature of the nanoparticles are being developed. This review presents and discusses the state-of-the-art analytical techniques and sample preparation methods suitable for dealing with complex samples. Single- and multi-method approaches applied to solve the nanometrological challenges posed by a variety of stakeholders are also presented.
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•The challenge to analyze inorganic nanomaterials is described.•Techniques for detection, characterization and quantification of inorganic nanomaterials are presented.•Sample preparation methods for the analysis of nanomaterials in complex samples are presented.•Methodological approaches posed by stakeholders for solving nanometrological problems are discussed.
Aim
This observational cohort study aimed: (i) to determine retrospectively after a 1‐ to 12‐year follow‐up period, the strength and independence of the association of various patient‐, tooth‐ and ...treatment‐related prognostic variables with the outcome of root canal treatment in patients with pre‐therapeutic apical periodontitis; and (ii) to establish the concordance between those predictors evaluated by both cone‐beam computed tomography (CBCT) and digital periapical radiography (DPR).
Methodology
The study cohort included 125 teeth in 84 individuals. The postoperative clinical signs/symptoms, plus DPR/CBCT‐PAI estimations, were used to determine the healing outcome. For statistical analysis, results were dichotomized into completely healed periapical structures versus persistent disease cases. The association between candidate predictor variables with persistent disease was analysed individually and adjusted for confounders using a multivariate binary logistic regression model.
Results
The success rate was 53.6%. After logistic regression analysis, mandibular tooth location, periapical lesion size >10 mm, poor quality of the coronal restoration, lack of magnification/illumination, lack of disinfection of gutta‐percha, time elapsed to definitive coronal restoration >1 week and poor density of root canal filling remained as robust predictors of failures. Concordance between DPR and CBCT scores varied from moderate to almost perfect agreement.
Conclusions
The findings of this study suggest that several tooth‐ and treatment‐related predictor variables, including tooth location, periapical radiolucency size, quality of the coronal restoration, magnification/illumination, disinfection of gutta‐percha, time elapsed to definitive coronal restoration, as well as, the density of root canal filling may act strongly and independently for determining the root canal treatment outcome in teeth with pre‐therapeutic apical periodontitis.
Silver in its various forms, including dissolved silver ions (Ag+) and silver nanoparticles (AgNPs), is a promising alternative to traditional antibiotics, largely used in livestock as feed additives ...and could contribute to the decrease and avoidance of the development of antibiotic resistance. The present study aims to assess the potential ecotoxicity of a silver-based nanomaterial (Ag-kaolin), the feed supplemented with the nanomaterial and the faeces since the latter are the ones that finally reach the environment. To this end, green alga Raphidocellis subcapitata was exposed to the extracts of Ag-kaolin, supplemented feed, and pig faeces for 72 h, along with Ag+ and AgNPs as controls for comparison purposes. Given the complexity of the studied materials, single-cell techniques were used to follow the changes in the cell numbers and chlorophyll fluorescence by flow cytometry, and the accumulation of silver in the exposed cells by single cell inductively coupled plasma mass spectrometry (SC-ICP-MS). Changes in cell morphology were observed by cell imaging multimode reader. The results revealed a decrease in chlorophyll fluorescence, even at low concentrations of Ag-kaolin (10 μg L−1) after 48 h of exposure. Additionally, complete growth inhibition was found with this material like the results obtained by exposure to Ag+. For the supplemented feed, a concentration of 50 μg L−1 was necessary to achieve complete growth inhibition. However, the behaviour differed for the leachate of faeces, which released Ag2S and AgCl alongside Ag+ and AgNPs. At 50 μg L−1, inhibition was minimal, primarily due to the predominance of less toxic Ag2S in the leachate. The uptake of silver by the cells was confirmed with all the samples through SC-ICP-MS analysis. These findings demonstrate that the use of Ag-kaolin as a feed supplement will lead to a low environmental impact.
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•Study of effect of silver-based nanomaterials used as feed additives to algae•Use of single cell techniques to study the effect on freshwater algae and silver uptake•Effect of silver-based materials was exposure concentration and time dependent.•Environmental impact for faeces of pigs fed with silver-based nanomaterial was low.
Freshwater has spatial and temporal constraints, affecting possibilities to generate electricity. Previous studies approached this from a water perspective quantifying water consumption of ...electricity to optimize water use, or from an electricity perspective using modeling methods to optimize electricity output. However, power plants consume different water volumes per unit of electricity, depending on the applied technology, and supply systems often include a mix of different technologies with a different water footprint (WF), an indicator of water consumption, per unit of electricity. When water availability varies in time, probably the contribution of different electricity generating technologies also varies in time, resulting in WF fluctuations. Focusing on electricity generation from the water perspective, we assessed how water availability affects an electricity mix's dynamics and its blue WF using Ecuador as a case study. We studied the Amazon and Pacific basins, which have different temporal and spatial water availability fluctuations, assessing monthly water availability, electricity production, and blue WFs per plant. The Amazon basin has smaller temporal and spatial availability fluctuations than the Pacific. The difference between the largest and smallest water availability in the Amazon basin is two-fold, in the Pacific four-fold. Hydropower generation in the Amazon basin contributes more than 60% to the electricity mix. However, hydropower is directly affected by water availability, and its production decreases in water-limited periods. For biomass plants, limited water availability affects the fuel source, sugarcane bagasse. As water availability decreases, other technologies in the mix take over, causing WF variation (from 4.8 to 8.6 103 m3 per month). Usually, less water-availability means more water-efficiency, implying fossil-fueled plants in the Pacific take over from hydropower in the Amazon. It is relevant to assess the water-electricity nexus in countries with electricity mixes dominated by hydropower because energy planning needs to consider water availability and electricity mix dynamics.
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•Even in water-abundant countries, water availability shows variation over the year.•The spatial and temporal variation in water availability affects electricity supply.•Water availability affects hydropower directly, and thermal and biomass indirectly.•Thermal plants compensate the decreased hydropower production in dryer months.•A hydropower-based electricity supply system needs backup systems for dry periods.
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