Arsenic is a potentially toxic element of concern for environmental compartments, and it is a frequent pollutant in many abandoned industrial sites. In this study, geochemical and hydrogeological ...tools were used to determine the long-term effects of As-rich pyrite ash disposal (83,000 m
3
as estimated by geostatistical tools) in a brownfield located over a quaternary alluvial aquifer. Throughout the site, soil pollution and water table oscillation led to leachates in the form of both run-off and infiltration waters, thereby reducing (ground)water quality (e.g. pH, electrical conductivity) and, in particular, increasing the concentration of arsenic (average approx. 4000 μg/l for one hydrological year). By means of laboratory and in situ measurements, the main mechanisms through which the sulphide remaining in the pyrite ash leaches were identified. In addition, to evaluate the effects of the polluted groundwater on the nearby main river, a mathematical approach using the Domenico analytical groundwater transport model revealed potential concentrations of 49 μg/l of arsenic in the junction between the study aquifer and the river, equivalent to an annual quantity of 49 kg of this element.
The crystallisation behaviour of calcium carbonate phases in the system Ca2+-Co2+-CO32−-H2O was examined in batch reactors. Experiments with different initial ratios of Co2+/Ca2+ (from 0 to 1.0) in ...the aqueous solution were performed to examine precipitation and mineral transformations under ambient conditions. The solids recovered from the aqueous solution after different ageing periods (ranging from 5 min to 2 months after precipitation) were characterised by X-ray diffraction, transmission and scanning electron microscopy and EDX microanalyses. The evolution of the aqueous solutions was also followed by measuring their pH and their chemical composition by UVA–visible spectroscopy. Our experimental data indicate that there are two sequences of solvent-mediated transformations in aged carbonates, one involving Co-rich phases and another involving calcium carbonates. Both sequences are characterised by the initial formation of amorphous or poorly crystalline hydrated phases, which transform into crystalline and anhydrous phases with ageing via a dissolution and reprecipitation mechanism. The stability and solubility of the phases are concerned with the incorporation of Co in Ca-bearing phases and Ca in the Co-bearing phases. Co-rich carbonates evolve from a hydrated amorphous hydroxycarbonate (Co2CO3(OH)2 ⋅H2O) to the crystalline phase Co2CO3(OH)2. The transformation from the amorphous to crystalline phase (Co2CO3(OH)2) was increasingly delayed as the initial Co/Ca ratio lowered. The sequence of Ca carbonates is affected by the amounts of Co2+ in the initial solution, and instead of the sequence ACC (amorphous calcium carbonate) → vaterite (Vtr) → calcite (Cal) obtained for control experiments, we observed ACC → monohydrocalcite → aragonite (Arg). Moreover, the Co2+/Ca2+ ratio controls the earliest calcium carbonate phases to appear and the subsequent polymorph transformation reactions. In terms of cobalt incorporation into the solids, monohydrocalcite and Arg incorporate a certain amount of cobalt into their crystalline structures. The thermodynamic solubility products of cobalt hydroxide carbonates (amorphous and crystalline) were determined. This experimental study advances the progress of understanding carbonate precipitation-dissolution-recrystallisation reactions under ambient conditions.
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•The presence of Co2+ in the aqueous phase modifies the precipitation sequence of calcium carbonates at room conditions.•For Co/Ca ratios lower than 0.6 in the fluid phase the precipitation sequence is ACC → monohydrocalcite → aragonite.•Cobalt-rich fraction of the precipitate evolves from an amorphous Co2CO3(OH)2 ⋅H2O to a crystalline Co2CO3(OH)2.•Both sequences imply dehydration and crystallisation from the preceding phases.•The slow kinetic of phase transformations is influenced by the long half-life of water exchange around Co2+.
The aim of the present study was to assess the relationship between serum concentrations of several persistent organic pollutants and insulin resistance markers in a cohort of women with a history of ...gestational diabetes mellitus. ∑POPs was computed as the sum of individual serum POP concentrations. No statistically significant associations were found between levels of any POP and fasting glucose. However, polychlorinated biphenyl (PCB) congeners 138 and 180 were positively associated with 2-h glucose levels and PCB 180 also with fasting immunoreactive insulin (IRI). We also found a positive association of p,p′- dichlorodiphenyldichloroethylene (p,p′- DDE), PCBs (138, 153, and 180), hexachlorobenzene, and ∑POPs with 2-h IRI. Serum concentrations of PCBs (138, 153, and 180), hexachlorobenzene, and ∑POPs were also positively associated with homeostasis model assessment (HOMA2-IR) levels. Moreover, p,p′- DDE, PCBs (138, 153 and 180), hexachlorobenzene, and ∑POPs were negatively associated with Insulin Sensitivity Index (ISI-gly) levels. No significant association was found between glycated hemoglobin and the concentrations of any POP. The removal of women under blood glucose lowering treatment from the models strengthened most of the associations previously found for the whole population. Our findings suggest that exposure to certain POPs is a modifiable risk factor contributing to insulin resistance.
•We studied the relationship between persistent pollutants and insulin resistance.•PCBs, HCB, and ∑POPs were positively associated with HOMA2-IR levels.•p,p′-DDE, PCBs, HCB, and ∑POPs were negatively associated with ISI-gly levels.•The removal of women under diabetes treatment strengthened most associations.•Exposure to persistent pollutants might be a risk factor for insulin resistance.
In a world where the ubiquity of Co-Li batteries in smartphones, laptops and electric vehicles is giving rise to an increase of cobalt concentration in mining soils and landfill leachates, the ...absorption of Co2+ ions by calcite provides a potential method to remove metal pollutants from aqueous media. Here, we show that the cobalt carbonates resulting from this process can be further recycled to produce lamellar Co3O4 nanoparticles with sizes around 30nm. The cores of the nanoparticles possess a Fd3¯m spinel crystal structure and order antiferromagnetically at a Néel temperature of TN∼35K. On the other hand, the loss of crystallinity in a 1–2nm-thick surface shell leads to the appearance of magnetically disordered spins. Finally, the magnetic exchange coupling between the core and shell spins gives rise to a moderate exchange bias effect (∼500 Oe) at T=5K.
The interaction of the calcite surface with Co2+-rich aqueous solutions (Co2+aqinitial = 1000 ppm, i.e., ca. 17 mM) was investigated by means of macroscopic experiments and surface spectroscopic ...techniques. In the case of the macroscopic experiments, calcite powder and monocrystals were immersed into solutions for different time periods (from 1 min to one month). The Ca concentrations in the filtrates was measured by means of atomic absorption spectrometry (AAS) while the interacted solids were studied using a combination of X-ray photoelectron spectroscopy (XPS) and 12C-rutherford backscattering spectrometry (12C-RBS). The macroscopic data showed a characteristic surface dissolution process, in parallel to the surface sorption processes. Adsorption and co-precipitation were seen for almost the entire immersion period for both calcite powder and monocrystals. The surface study by XPS (analyzed at a depth of approximately 12 nm) suggested that adsorption takes place in the first hour of the interaction, followed by incorporation of Co2+ into calcite surface layers, leading to the formation of a Co2+-bearing surface (co)precipitate, which occurs over a period of hours and days. The 12C-RBS measurements on calcite { 10 1 ¯ 4 } indicated that the thickness of this surface co-precipitate was 270 nm after one day and then stabilized at 320 nm after more than a week.
A better understanding of the prognostic factors of low bone mass in anorexia nervosa (AN) and development of effective therapeutic strategies is critical. In order to determine which clinical, ...biochemical, and/or hormonal parameters could be related to bone mineral density (BMD), 47 female AN patients were classified according to the WHO osteoporosis criteria at lumbar spine (LS). This was a cross-sectional study of 16 AN women with osteoporosis criteria and 31without. Control group was 25 healthy, normal-weight, age-matched women. We assessed BMD using dual-energy X-ray absorptiometry at the LS and body composition. We measured serum fasting cortisol, estradiol, insulin-like growth factor-1 (IGF-1), leptin, sex hormone-binding globulin, albumin and retinol binding protein levels. The prevalence of osteoporosis was 34% and osteopenia 19% at the LS. The AN group with osteoporosis had lower IGF-1 and estradiol levels (both p<0.001), lower serum leptin (p<0.02), and higher cortisolemia (p<0.03) levels compared with AN group without osteoporosis. The BMD and T-score at LS was inversely related to the duration of amenorrhea (p<0.02) and directly related to body mass index (BMI, p<0.002), total fat mass (p<0.03), serum IGF-1 (p<0.01), and estradiol levels (p<0.001) in AN patients. We conclude that AN women with a significant BMD loss have a high risk of developing osteoporosis. A low BMD is a consequence of hormonal alterations which include hypoestrogenism, hypoleptinemia, hypercortisolism, and decreases in IGF-1 levels, as well as a low BMI and fat mass.
Introducción: Nutrire® es un programa informático, fruto de tres proyectos de innovación docente de la Universidad de Granada (España), que permite la valoración del estado nutricional mediante a ...partir de parámetros antropométricos, dietéticos y bioquímicos. Objetivo: El objetivo de este trabajo es presentar los resultados obtenidos de la evaluación global del programa por alumnos y egresados para poder analizar sus puntos fuertes y débiles que sirvan con posterioridad para realizar las modificaciones oportunas. Material y Métodos: Se ha realizado una encuesta anónima a 128 alumnos de 3 titulaciones de grado y 1 de postgrado de la Universidad de Granada. Se incluye 6 preguntas sobre navegabilidad y diseño y 5 sobre contenidos académicos del programa. Asimismo, se han entrevistado a 20 egresados que lo han utilizado en su actividad profesional. Resultados: La puntuación media obtenida en los alumnos fue de 4,1 sobre 5. Como aspectos positivos destacan: facilidad de uso, incorporación de fotografías de alimentos para elegir el tamaño de ración/porción. Como aspectos de mejora señalan: incorporar más fotos de alimentos, el poder instalar el programa para su uso en un ordenador. Según los egresados, el principal punto fuerte es tener reunido en un solo programa los tres aspectos de la evaluación del estado nutricional. Como puntos débiles señalan la falta de algún nutriente, como los azucares, en la base de datos nutricional. Conclusión: Nutrire® es un programa de fácil utilización, muy bien valorada por los alumnos y por los egresados para realizar estudios de evaluación del estado nutricional.
We aimed to assess the mid-term type 2 diabetes mellitus recovery patterns in morbidly obese patients by comparing some relevant physiological parameters of patients of bariatric surgery between two ...types of surgical procedures: mixed (roux-en-Y gastric bypass and biliopancreatic diversion) and restrictive (sleeve gastrectomy).
This is a prospective and observational study of co-morbid, type 2 diabetes mellitus evolution in 49 morbidly obese patients: 37 underwent mixed surgery procedures and 12 a restrictive surgery procedure. We recorded weight, height, body mass index, and glycaemic, lipid, and nutritional blood parameters, prior to procedure, as well as six and twelve months post-operatively. In addition, we tested for differences in patient recovery and investigated predictive factors in diabetes remission.
Both glycaemic and lipid profiles diminished significantly to healthy levels by 6 and 12 months post intervention. Type 2 diabetes mellitus showed remission in more than 80% of patients of both types of surgical procedures, with no difference between them. Baseline body mass index, glycated haemoglobin, and insulin intake, among others, were shown to be valuable predictors of diabetes remission one year after the intervention.
The choice of the type of surgical procedure did not significantly affect the remission rate of type 2 diabetes mellitus in morbidly obese patients. (Endokrynol Pol 2017; 68 (1): 18-25).
The cobalt carbonate hydroxide Co2CO3(OH)2 is a technologically important solid which is used as a precursor for the synthesis of cobalt oxides in a wide range of applications. It also has relevance ...as a potential immobilizer of the toxic element cobalt in the natural environment, but its detailed crystal structure is so far unknown. The structure of Co2CO3(OH)2 has now been investigated using density functional theory (DFT) simulations and powder X‐ray diffraction (PXRD) measurements on samples synthesized via deposition from aqueous solution. Two possible monoclinic phases are considered, with closely related but symmetrically different crystal structures, based on those of the minerals malachite Cu2CO3(OH)2 and rosasite Cu1.5Zn0.5CO3(OH)2, as well as an orthorhombic phase that can be seen as a common parent structure for the two monoclinic phases, and a triclinic phase with the structure of the mineral kolwezite Cu1.34Co0.66CO3(OH)2. The DFT simulations predict that the rosasite‐like and malachite‐like phases are two different local minima of the potential energy landscape for Co2CO3(OH)2 and are practically degenerate in energy, while the orthorhombic and triclinic structures are unstable and experience barrierless transformations to the malachite phase upon relaxation. The best fit to the PXRD data is obtained using a rosasite model monoclinic with space group P1121/n and cell parameters a = 3.1408 (4) Å, b = 12.2914 (17) Å, c = 9.3311 (16) Å and γ = 82.299 (16)°. However, some features of the PXRD pattern are still not well accounted for by this refinement and the residual parameters are relatively poor. The relationship between the rosasite and malachite phases of Co2CO3(OH)2 is discussed and it is shown that they can be seen as polytypes. Based on the similar calculated stabilities of these two polytypes, it is speculated that some level of stacking disorder could account for the poor fit of the PXRD data. The possibility that Co2CO3(OH)2 could crystallize, under different growth conditions, as either rosasite or malachite, or even as a stacking‐disordered phase intermediate between the two, requires further investigation.
The crystal structure of cobalt carbonate hydroxide Co2CO3(OH)2, a solid important in materials and environmental science, is investigated using density functional theory (DFT) simulations and powder X‐ray diffraction (PXRD) measurements.
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