RESUMO
Due to adverse impact of the global warming on hydrological resources, we intended to document the hydrogeochemical evolutions of surface and groundwater at tropical central-south Mexico in terms of seasonality of rock-water interaction, precipitation/evaporation variation and moisture source by evaluating the major ion chemistry in Piper and Gibbs plots, Durov diagram and through estimation of the chloro-alkaline indices as well as assessing the stable isotope compositions (δ18O and δ2H) in samples from different seasons of a year. Surface water of the Lake Coatetelco shifted from mostly Ca-Mg-HCO3 facies in wet summer-autumn to Na-HCO3-Cl facies in the dry spring due to elevated Na, Cl and HCO3. Greater evaporation in spring led to a maximum δ18O enrichment of ca.7 compared to the other seasons, and much depleted deuterium excess (-40.92 to -39.20). Interaction of the lake water with subsurface carbonate lithologies, and comparable isotopic compositions reflected the enhanced interaction between the surface water body and aquifers in the wet autumn. Effect of seasonality, however, was unclear on the groundwater facies, and its heterogenous composition (Ca-Mg-HCO3, Na-HCO3-Cl and Na-HCO3) reflected the interactions with different lithologies. Fractionations in isotope compositions of the groundwater were caused from recharge at different elevations, seasonality of moisture sources and moisture recycling. The water-mineral saturation index was an efficient proxy of seasonality as the lake water and groundwater (avg SIcalcite > 0.5) of the dry autumn were saturated with calcite. This vital information about carbonate precipitation, pCO2 and chemical facies would be useful for the better interpretation of paleoclimate archives in this region.
Assuntos
Deutério , Água Subterrânea , Isótopos de Oxigênio , Estações do Ano , México , Água Subterrânea/química , Água Subterrânea/análise , Isótopos de Oxigênio/análise , Deutério/análise , Monitoramento Ambiental/métodos , Lagos/químicaRESUMO
BACKGROUND: The use of plant protein intrinsically labelled with stable isotopes provides an innovative solution to assess the efficiency of protein intake by humans. Here, the incorporation of 2H has been applied to intrinsically labelled plant protein in the common bean. This study aimed to evaluate which is the best phenological phase of seed maturation to incorporate the heavy hydrogen isotope 2H into seed amino acids. Common beans (Phaseolus vulgaris L.) were grown in pots, then, after 50 days sowing, 2H2O dissolved in irrigation water was applied, then again at an interval of either 3, 6, 9, and 12 days. RESULTS: Applications of 2H2O at 6, 9, and 12 days after the first application, in the full-flowering stage, were the best treatments for enriching protein-bound amino acids in the bean seed with 2H. CONCLUSION: All treatments resulted in enrichment above 500 ppm, so the treatments (quantity and timing of 2H2O addition) were deemed successful for enriching bean seeds. This makes the intrinsically labelled seeds suitable for preparing test meals to assess the digestion and essential amino acid absorption of common bean amino acids in human subjects.
Assuntos
Phaseolus , Humanos , Proteínas de Plantas , Aminoácidos , Aminoácidos Essenciais , DeutérioRESUMO
The surface assessment via grid evaluation (SuAVE) software was developed to account for the effect of curvature in the calculations of structural properties of chemical interfaces regardless of the chemical composition, asymmetry, and level of atom coarseness. It employs differential geometry techniques, enabling the representation of chemical surfaces as fully differentiable. In this article, we present novel developments of SuAVE to treat closed surfaces and complex cavity shapes. These developments expand the repertoire of curvature-dependent analyses already available in the previous version of SuAVE (e.g., area per lipid, density profiles, membrane thickness, deuterium-order parameters, volume per lipid, and surface curvature angle) to include new functionalities applicable to soft matter (e.g., sphericity, average radius, principal moment of inertia, and roundness) and crystalline porous materials (e.g., pore diameter, internal void volume, total area, and the total void volume of the unit cell structure). SuAVE can accurately handle chemical systems with high and low atom density as demonstrated for two distinct chemical systems: the lipid A vesicle and a set of selected metal-organic frameworks. The SuAVE software v2.0 is fully parallel and benefits from a compiler that supports OpenMP. SuAVE is freely available from https://github.com/SuAVE-Software/source and https://www.biomatsite.net/.
Assuntos
Lipídeo A , Estruturas Metalorgânicas , Deutério , SoftwareRESUMO
INTRODUCTION: The 2030 health agenda for the United Nations Sustainable Development Goals promote exclusive breastfeeding (EBF) for the first 6 months of life as a central step towards ensuring the survival of infants. As Jamaica attempts to achieve this goal, monitoring the rates of EBF is desirable. Currently, EBF rate is measured by questionnaires which are subject to recall and social desirability biases. We determined the rate of EBF using the Deuterium-oxide dose-to-mother (DTM) method and 24-h recall. The concordance of both methods and urban-rural differences of EBF were evaluated. Additionally, the growth of infants who were exclusively breastfed was compared to the infants who were mixed-fed. METHODS: Sixty-one healthy mother-child pairs were followed from birth. EBF was measured at 6 weeks. Growth was determined using standard anthropometric measurements. Differences in means were assessed by independent t-test or ANOVA. The agreement between the DTM and 24-h recall method was assessed with the kappa statistic. Differences in anthropometry and location were determined using a repeated measure model approach. RESULTS: Thirty (49%) women exclusively breastfed their infants with mean breast milk intake of 1024.3 ± 256.9 g/day. There was moderate agreement between the methods (Agreement 69%, kappa 0.37, p = 0.002). Rural women (65%) were more likely to practice exclusive breastfeeding. There was no significant difference between the growth of the exclusively breastfed infant and mixed-fed infants. CONCLUSION: EBF rate was successfully measured using the DTM method. Women from urban settings are less likely to practice EBF. Further research may be needed to gain an in-depth understanding of the factors affecting breastfeeding practices in urban Jamaica.
Assuntos
Aleitamento Materno , Mães , Deutério , Feminino , Humanos , Lactente , Jamaica , Masculino , ÓxidosRESUMO
In the technique presented here, dubbed 'qMRS', we quantify the change in 1H MRS signal following administration of 2H-labeled glucose. As in recent human DMRS studies, we administer [6,6'-2H2]-glucose orally to healthy subjects. Since 2H is not detectable by 1H MRS, the transfer of the 2H label from glucose to a downstream metabolite leads to a reduction in the corresponding 1H MRS resonance of the metabolite, even if the total concentration of both isoforms remains constant. Moreover, introduction of the deuterium label alters the splitting pattern of the proton resonances, making indirect detection of the deuterated forms- as well as the direct detection of the decrease in unlabeled form- possible even without a 2H coil. Because qMRS requires only standard 1H MRS acquisition methods, it can be performed using commonly implemented single voxel spectroscopy (SVS) and chemical shift imaging (CSI) sequences. In this work, we implement qMRS in semi-LASER based CSI, generating dynamic maps arising from the fitted spectra, and demonstrating the feasibility of using qMRS and qCSI to monitor dynamic metabolism in the human brain using a 7T scanner with no auxiliary hardware.
Assuntos
Glucose , Imageamento por Ressonância Magnética , Deutério , Glucose/metabolismo , Humanos , Imageamento por Ressonância Magnética/métodos , Espectroscopia de Ressonância Magnética/métodos , Espectroscopia de Prótons por Ressonância MagnéticaRESUMO
Mountains arid environments are vulnerable under climate change scenarios. Variations in the recharge sources and the rising temperature can affect the water availability, threaten the socio-productive systems on local and regional scales. In this sense, two hydrological systems were studied in the Andes Range, Argentina, by hydrochemical and isotope techniques, with the purpose to understand the origin of water, the groundwater recharge, and to conceptualize the groundwater flow system. In the two sampling periods (winter and summer seasons) most of the waters were characterized by low mineralization and a HCO3-Ca type. The isotopic composition showed wide ranges of variation consistent with the altitudinal differences existing in the study systems. However, no significant isotope changes were observed between the samples collected in winter and summer periods. Therefore, little influence of liquid precipitation is inferred in the recharge source of both hydrological systems. This means that the western sector of the valley, where the ice bodies and permafrost are located, is the main recharge area for groundwater of both basins. This confirms the former hypothesis used for the hydrogeochemical conceptual model proposed, and highlights the importance of protecting these environments to ensure the provision of water in arid lands.
Assuntos
Bicarbonatos/análise , Deutério/análise , Água Subterrânea/análise , Modelos Teóricos , Isótopos de Oxigênio/análise , Argentina , Hidrologia , Estações do AnoRESUMO
The Corumbataí River basin (São Paulo, Brazil) has a critical situation regarding water availability due to the intensive use to support agriculture and urbanization, requiring scientific information to face water demand. The aim of this study is to present a hydrological characterization based on the analysis of seasonal isotope variations (rainfall, groundwater, and surface water) and hydrometric data. Results indicate that baseflow contribution varies from 50â % to 70â % of the total flow, and water isotopic composition denotes a seasonal regime marked by the mixing of surface and groundwater in the wet period and groundwater discharge during the dry season. The results presented indicated the strong seasonal connection between atmospheric inputs and water movement across the basin, which poses an urgent need to diversify monitoring methods and create feasible regional and political regulations to control the effects on basin water resilience in the face of climate change and growing demand.
Assuntos
Água Subterrânea/química , Rios/química , Brasil , Mudança Climática , Deutério/análise , Monitoramento Ambiental/métodos , Água Subterrânea/análise , Hidrologia , Isótopos de Oxigênio/análise , Estações do Ano , Análise Espaço-Temporal , Movimentos da ÁguaRESUMO
The minimum chemical modification that can be incorporated into an organic molecule is the replacement of a hydrogen atom for a deuterium atom. This change is not altering the pharmacological properties of a molecule, although it provides the possibility of making specific spectroscopic evaluations. Thus, in the present study, we explore how a stereogenic center is influenced by such an isotopic labeling. The studies were conducted on both enantiomers of flavanone (1 and 2) which is the parent molecule of a large group of pharmacologically active natural occurring secondary metabolites. Flavanone comprised 12 carbon atoms forming two benzene rings, a carbonyl group, an ethereal oxygen atom, a methylene group, and only one C-H stereogenic center, so it seems to be an ideal candidate for such studies. Density functional theory (DFT) calculations were used for the accurate prediction of vibrational circular dichroism (VCD) spectra of (R)-(3) and (S)-flavanone-2-d (4), of (R)-(5) and (S)-flavanone-3,3-d2 (6), and of (R)-(7) and (S)-flavanone-2',3',4',5',6'-d5 (8). To gain compounds that provide experimental VCD spectra for comparative purposes, the calculated spectra of both enantiomers of the corresponding flavanones, obtained after HPLC separation of the racemates by means of a chiral column, were contrasted, thereby revealing excellent agreements when using the CompareVOA software. In addition, the VCD spectra of both unlabeled enantiomeric flavanones (1 and 2) were also compared to the labeled molecules, revealing that the VCD spectra show significant variations induced by the deuterium incorporation.
Assuntos
Dicroísmo Circular , Deutério/química , Flavanonas/química , Modelos Moleculares , Conformação Molecular , EstereoisomerismoRESUMO
The mid-latitude coastal area at the western South-Atlantic out of the tropics is under the combined effect of different atmospheric circulation patterns at different temporal scales, which can be shown by the isotope composition of precipitation. This pattern effect is more changing and complex than that for the well-studied tropical areas, the isotope studies being an interesting proxy for identifying major processes. This study is focused on the isotope composition of precipitation at a mid-latitude zone, in the western South-Atlantic coastal area of Argentina. δ18O and d-excess were analysed in a data series of 14 years, obtained from the integration of three neighbouring rain collectors at 38°S. A seasonality is observed in both parameters, but with some differences in the extreme months. δ18O showed a seasonality according to the temperature effect, but with a displacement of high values to spring months. Significant linear links between δ18O and Southern Annular Mode (SAM) index and Southern Oscillation Index (SOI) were recognised for the summer and spring seasons, respectively.
Assuntos
Atmosfera/química , Deutério/análise , Monitoramento Ambiental/métodos , Isótopos de Oxigênio/análise , Chuva/química , Ciclo Hidrológico , Argentina , Oceano Atlântico , Modelos Teóricos , Estações do AnoRESUMO
Hosting the flattest sedimentary plains and highest Andean range of the continent, southern South America faces hydrological transformations driven by climate and land use changes. Although water stable isotopes can help understand these transformations, regional synthesis on their composition is lacking. We compiled for the first time a dataset of H and O isotopic composition for 1659 samples (precipitation, rivers, groundwater and lakes) along latitude (22.4°S to 41.6°S), longitude (55.3°W to 71.5°W), elevation (1-4700â m) and precipitation (â¼50 to â¼1500â mm/a) gradients encompassing the Chaco-Espinal-Pampas plains, their adjacent Andean Cordillera and smaller mountain ranges in-between. Emerging patterns reveal (i) only slight seasonal isotope trends in precipitation with no effects of event size, (ii) Atlantic/Amazonian vs. Pacific moisture supply to rivers north and south of the 'arid diagonal' of the continent, respectively, (iii) uniform isotopic composition in Atlantic/Amazonian-fed rivers vs. poleward isotope enrichment in Pacific-fed rivers caused by the elevation decline of the Andes, (iv) strong direct evaporation effect in rivers and shallow (<1â m) phreatic groundwater of the plains. We provide the first integrated water isotope geographical patterns of southern South America helping to improve our understanding of its water cycling patterns at the atmosphere and the land.