Drinking water provision and quality at the Sahrawi refugee camps in Tindouf (Algeria) from 2006 to 2016.

Drinking water provision has been a constant challenge in the Sahrawi refugee camps, located in the desert near Tindouf (Algeria). The drinking water supply system is itself divided in three zones which pump groundwater from different deep aquifers. It is equipped with reverse osmosis plants and chlorination systems for treating water. The allocation of water supplied to the Saharawi refugees for human consumption in 2016 has been estimated at between 14 and 17 L/person/day on average. This supplied water volume is below recommended standards, and also below the strategic objective of the Sahrawi government (20 L/person/day). Yet the local groundwater resources are huge in comparison with estimated consumption, and hence there is great potential for increasing the supplied volume through effecting improvements in the supply system. The physico-chemical quality of the raw and supplied water between 2006 and 2016 has been assessed according to Algerian standards for human consumption. The raw water of two zones of the supply system presents a very high conductivity and high concentrations of chloride, nitrate, fluoride, sulfate, sodium, calcium, potassium and iodide concentrations of natural origin, which may entail health risks. The treatment of water in a reverse osmosis plant greatly improves its quality and osmosed water met the standards. However, the supply of osmosed and raw water needs to be combined in Zone 1, to avoid an excessive reduction in water volume, and the supplied raw water poses a risk to the health of the refugees. The present study provides an example of a drinking water supply system under extreme drought conditions and in the political and social conditions of a refugee camp. Furthermore, it establishes a reference for supplied water allocation and quality in the Sahrawi refugee camps.

Clinical risk factors for the prediction of acute kidney injury post cardiac resynchronization therapy in an elderly population.

BACKGROUND: Data on the occurrence of acute kidney injury (AKI) in patients undergoing cardiac resynchronization therapy (CRT) implantation is limited and no previous studies investigated its impact in an elderly population. CRT implantation requires a relatively low quantity of contrast medium. Previous studies, however, focused primarily on contrast medium as etiological factor for AKI, reporting a high incidence (8-14%). The high incidence of AKI in absence of use of substantial amounts of contrast volume, suggests the existence of other factors that contribute to AKI. OBJECTIVES: To determine the predictive value of patient and procedure-related risk factors for the occurrence of AKI post CRT, as well as the AKIs impact on length of in-hospital stay (LOS) and 1-year mortality. METHODS: Retrospective observational study, including consecutive patients that underwent CRT implantation in a single center. RESULTS: 60 patients with a mean age of 77 ± 8.4 years were included in the study and Twelve (20%) developed AKI. Prior renal insufficiency (p = 0.03; OR = 15.4), larger procedure time (p = 0.02; OR = 1.03), intra-operative hypotension (p < 0.01; OR = 1.72) and bleeding (p = 0.01 (OR = 7.86), showed to predict AKI significantly. AKI associated a significantly longer LOS (12 vs 3 days, p < 0.01). No significant differences regarding 1-year mortality were observed (p = 0.19; HR = 2.7 for patients with AKI). CONCLUSIONS: AKI is a frequent complication of CRT implantation with an important impact on in-hospital stay, especially in the elderly. In addition to contrast administration, clinical factors could play a significant role in the occurrence of AKI.

Clinical outcomes of PCI with rotational atherectomy: the European multicentre Euro4C registry.

AIMS: Despite the use of rotational atherectomy (RA) in interventional cardiology for over three decades, data regarding factors affecting the clinical outcomes of the RA procedure remain scarce. The aim of the present study was to describe the contemporary use and outcomes of RA in Europe. METHODS AND RESULTS: We conducted, for the first time, a prospective international registry in 8 European countries and 19 centres and included patients treated by percutaneous coronary intervention with RA. Between October 2016 and July 2018, 966 patients with complete data were recruited. Mean age was 74.5 years, 72.4% were male and 43.4% had diabetes. Initial presentation was an acute coronary syndrome (ACS) for 25.1% of the patients. Clinical success was observed in 91.9% of the procedures. The rate of in-hospital major adverse cardiac events (MACE) - defined as cardiovascular death, myocardial infarction, target lesion revascularisation, stroke and coronary artery bypass grafting - was 4.7%. At one year, the rate of MACE was 13.2%. Factors independently associated with the occurrence of MACE at one year were female gender, renal failure, ACS at admission, depressed left ventricular ejection fraction (LVEF) and presence of a significant left main coronary artery (LMCA) lesion. CONCLUSIONS: Despite the high level of complexity of the studied population, RA turned out to be an effective procedure with a low rate of in-hospital complications and demonstrated good immediate and midterm results.

Coronary artery aneurysms, insights from the international coronary artery aneurysm registry (CAAR).

BACKGROUND: Coronary Aneurysms are a focal dilatation of an artery segment >1.5-fold the normal size of adjacent segments. Although some series have suggested a prevalence of 0.3-12%, data are lacking. In addition, they are not mentioned in practice guidelines. Our aim was investigate its prevalence, management and long-term outcomes. METHODS AND RESULTS: The coronary artery aneurysm registry (CAAR) involved 32 hospitals across 9 countries in America and Europe. We reviewed 436,467 consecutive angiograms performed over the period 2004-2016. Finally, 1565 patients were recruited. Aneurysm global prevalence was 0.35%. Most patients were male (78.5%) with a mean age of 65 years and frequent cardiovascular risk factors. The main indication for angiogram was an acute coronary syndrome, 966 cases. The number of aneurisms was ≤2 per patient in 95.8% of the cases, mostly saccular, most frequently found in the left anterior descending and with numbers proportional with coronary stenosis. Aortopathies were related with more aneurysms too. Most patients received any revascularization procedure (69%), commonly percutaneous (53%). After a median follow-up of 37.2 months, 485 suffered a combined event (MACE) and 240 died. Without major differences comparing CABG vs PCI, MACE and death were more frequent in patients who received bare metal stents. CONCLUSIONS: Coronary artery aneurysms are not uncommon. Usually, they are associated with coronary stenosis and high cardiovascular risk. Antiplatelet therapy seems reasonable and a percutaneous approach is safe and effective.

Transport of oxygen into granitic rocks: Role of physical and mineralogical heterogeneity.

The rock matrix of granites is expected to be an important buffer against the dispersion of contaminants, e.g. radionuclides, and against the ingress of oxygenated glacial meltwater. The influence of matrix heterogeneity on O2 diffusive transport is assessed here by means of numerical experiments based on a micro-Discrete Fracture Network (micro-DFN) representation of the diffusion-available pore space along with random realisations of idealized biotite grains, to simulate the heterogeneous nature of granitic rocks. A homogeneous-based analytical solution is also presented and used to assess possible deviations of the numerical experiments from the assumption of homogeneity. The analytical solution is also used to test upscaled values of mineral surface area. The numerical experiments show that the matrix behaves as a composite system, with the coexistence of fast and slow diffusive pathways. This behavior is more evident at low Damköhler numbers. Our interpretation of the numerical experiments points out the importance to properly characterise the heterogeneity of the rock matrix.

TUSARC: Prognostic Value of High-Sensitivity Cardiac Troponin T Assay in Asymptomatic Patients with High Cardiovascular Risk.

BACKGROUND: Prognostic value of high-sensitivity cardiac troponin T (hs-cTnT) assays have been assessed in selected populations in different studies and in registries of members of the general population with low cardiovascular risk. The aim of this study was to determine the prognostic value of hs-cTnT in an asymptomatic very-high cardiovascular risk Spanish population. METHODS: From a previous prospective cohort of the TUSARC (troponina T UltraSensible en pacientes Asintomáticos de alto Riesgo Cardiovascular) registry, follow-up was conducted in 602 patients (93.18%). The association of high hs-cTnT (≥99th percentile value) and incidence of primary event was studied. A primary event was defined as a combined major cardiovascular event (incidence of cardiovascular death, decompensated heart failure, non-fatal cerebrovascular event, non-fatal myocardial infarction, or coronary revascularization). The association between high hs-cTnT and incidence of secondary events was studied as well. RESULTS: In patients with high hs-cTnT, the incidence of primary event during follow-up was significantly higher (18.30% vs 3.67% P < .001): heart failure (6.25% vs 0.73% P < .001), cardiovascular death (7.29% vs 0.00% P < .001), and death from any cause (7.81% vs 0.98% P < .001). CONCLUSIONS: In an asymptomatic very-high cardiovascular risk Spanish population, elevated hs-cTnT was significantly associated with incident major cardiovascular combined end point and incidence of heart failure, cardiovascular death, and death from any cause.

Microtomography-based Inter-Granular Network for the simulation of radionuclide diffusion and sorption in a granitic rock.

Field investigation studies, conducted in the context of safety analyses of deep geological repositories for nuclear waste, have pointed out that in fractured crystalline rocks sorbing radionuclides can diffuse surprisingly long distances deep into the intact rock matrix; i.e. much longer distances than those predicted by reactive transport models based on a homogeneous description of the properties of the rock matrix. Here, we focus on cesium diffusion and use detailed micro characterisation data, based on micro computed tomography, along with a grain-scale Inter-Granular Network model, to offer a plausible explanation for the anomalously long cesium penetration profiles observed in these in-situ experiments. The sparse distribution of chemically reactive grains (i.e. grains belonging to sorbing mineral phases) is shown to have a strong control on the diffusive patterns of sorbing radionuclides. The computed penetration profiles of cesium agree well with an analytical model based on two parallel diffusive pathways. This agreement, along with visual inspection of the spatial distribution of cesium concentration, indicates that for sorbing radionuclides the medium indeed behaves as a composite system, with most of the mass being retained close to the injection boundary and a non-negligible part diffusing faster along preferential diffusive pathways.

Continuum-based DFN-consistent numerical framework for the simulation of oxygen infiltration into fractured crystalline rocks.

We present an enhanced continuum-based approach for the modelling of groundwater flow coupled with reactive transport in crystalline fractured rocks. In the proposed formulation, flow, transport and geochemical parameters are represented onto a numerical grid using Discrete Fracture Network (DFN) derived parameters. The geochemical reactions are further constrained by field observations of mineral distribution. To illustrate how the approach can be used to include physical and geochemical complexities into reactive transport calculations, we have analysed the potential ingress of oxygenated glacial-meltwater in a heterogeneous fractured rock using the Forsmark site (Sweden) as an example. The results of high-performance reactive transport calculations show that, after a quick oxygen penetration, steady state conditions are attained where abiotic reactions (i.e. the dissolution of chlorite and the homogeneous oxidation of aqueous iron(II) ions) counterbalance advective oxygen fluxes. The results show that most of the chlorite becomes depleted in the highly conductive deformation zones where higher mineral surface areas are available for reactions.

Troponina T ultrasensible en pacientes asintomáticos de muy alto riesgo cardiovascular. Registro TUSARC / High-sensitivity troponin T assay in asymptomatic high cardiovascular risk patients. The TUSARC Registry

Introducción y objetivos: La troponina T ultrasensible (TnT-us) se ha cuantificado en poblaciones de ensayos clínicos y en registros poblacionales de bajo riesgo cardiovascular (RCV). El objetivo del estudio es determinar en qué proporción de la población española asintomática de muy alto RCV se puede cuantificar la TnT-us, qué proporción presenta TnT-us elevada y qué variables se asocian con la presencia de TnT-us elevada. Métodos: Se incluyó a 690 pacientes. Se analizó la detección de la TnT-us y de la TnT-us elevada (≥ percentil 99 de referencia) y su asociación con las diferentes variables recogidas. Resultados: Se analizó la TnT-us en 646 pacientes y se detectó en 645. Presentaron TnT-us elevada 212 pacientes (32,9%). En el análisis multivariable, la TnT-us elevada se asoció al sexo masculino (OR = 2,81; IC95%, 1,67-4,73; p < 0,001), mayor edad (OR = 1,06; IC95%, 1,04-1,09; p < 0,001) mayor índice de masa corporal (OR = 1,07; IC95%, 1,02-1,12; p < 0,002), tratamiento con insulina (OR = 1,99; IC95%, 1,15-3,46; p = 0,01), insuficiencia cardiaca previa (OR = 3,92; IC95%, 1,24-12,39; p = 0,02) y filtrado glomerular estimado calculado por la fórmula CKD-EPI (OR = 0,96; IC95%, 0,95-0,97; p < 0,001). Conclusiones: En una población española asintomática de muy alto RCV, la TnT-us se detectó prácticamente en todos los pacientes, y estaba elevada en un tercio de ellos. La TnT-us elevada se asoció a mayor edad, el sexo masculino, el índice de masa corporal, la insuficiencia cardiaca previa, el tratamiento con insulina y un menor filtrado glomerular (AU)

Introduction and objectives: High-sensitivity troponin T assays (Hs-TnT) have been carried out in selected populations in clinical trials and in registries of the general population with low cardiovascular risk (CVR). The aim of this study was to determine the proportion of individuals with detectable Hs-TnT and the proportion of individuals with elevated Hs-TnT in a Spanish population of asymptomatic individuals with very high CVR, as well as the parameters associated with Hs-TnT elevation. Methods: The study included 690 patients. Hs-TnT detection and Hs-TnT elevation (≥99th percentile value), as well the association of elevated Hs-TnT and clinical, analytical, and treatment data were analyzed. Results: Hs-TnT was analyzed in 646 patients and was detected in 645. Elevated TnT was detected in 212 patients (32.9%). On multivariate analysis, elevated TnT was independently associated with male sex (OR, 2.81; 95%CI, 1.67-4.73; P < .001), older age (OR, 1.06; 95%CI, 1.04-1.09; P < .001), a higher body mass index (OR, 1.07; 95%CI, 1.02-1.12; P < .002), insulin therapy (OR, 1.99; 95%CI, 1.15-3.46; P = .01), history of heart failure (OR, 3.92; 95%CI, 1.24-12.39; P = .02), and estimated glomerular filtration rate calculated by CKD-EPI (OR, 0.96; 95%CI, 0.95-0.97; P < .001). Conclusions: In a Spanish population of asymptomatic individuals at very high CVR, Hs-TnT was associated with older age, male sex, higher body mass index, insulin therapy, history of heart failure, and lower glomerular filtration rate (AU)

High-sensitivity Troponin T Assay in Asymptomatic High Cardiovascular Risk Patients. The TUSARC Registry.

INTRODUCTION AND OBJECTIVES: High-sensitivity troponin T assays (Hs-TnT) have been carried out in selected populations in clinical trials and in registries of the general population with low cardiovascular risk (CVR). The aim of this study was to determine the proportion of individuals with detectable Hs-TnT and the proportion of individuals with elevated Hs-TnT in a Spanish population of asymptomatic individuals with very high CVR, as well as the parameters associated with Hs-TnT elevation. METHODS: The study included 690 patients. Hs-TnT detection and Hs-TnT elevation (≥99th percentile value), as well the association of elevated Hs-TnT and clinical, analytical, and treatment data were analyzed. RESULTS: Hs-TnT was analyzed in 646 patients and was detected in 645. Elevated TnT was detected in 212 patients (32.9%). On multivariate analysis, elevated TnT was independently associated with male sex (OR, 2.81; 95%CI, 1.67-4.73; P < .001), older age (OR, 1.06; 95%CI, 1.04-1.09; P < .001), a higher body mass index (OR, 1.07; 95%CI, 1.02-1.12; P < .002), insulin therapy (OR, 1.99; 95%CI, 1.15-3.46; P = .01), history of heart failure (OR, 3.92; 95%CI, 1.24-12.39; P = .02), and estimated glomerular filtration rate calculated by CKD-EPI (OR, 0.96; 95%CI, 0.95-0.97; P < .001). CONCLUSIONS: In a Spanish population of asymptomatic individuals at very high CVR, Hs-TnT was associated with older age, male sex, higher body mass index, insulin therapy, history of heart failure, and lower glomerular filtration rate.

Brain natriuretic peptide levels variation after left atrial appendage occlusion.

OBJECTIVE: To explore the variations of brain natriuretic peptide (BNP) secretion after left atrial appendage occlusion. BACKGROUND: Left atrial appendage occlusion has been increasingly performed in the last few years, however little is known about the physiological consequences of left atrial appendage occlusion. Left atrial appendage regulates partially intravascular volume via release of brain natriuretic peptide. Brain natriuretic peptide levels have been related to increased risk of stroke in atrial fibrillation patients. METHODS: Venous blood samples were obtained in consecutive patients undergoing left atrial appendage occlusion before, 24 hr after device implantation and at the first visit after discharge (45-60 days) for BNP measurement. RESULTS: Left atrial appendage occlusion was performed in 34 patients with non-valvular atrial fibrillation and contraindication to long-term oral anticoagulation or at high-risk of bleeding. There were no differences in BNP levels between baseline and 24 hr after device implantation. However left atrial appendage closure resulted in a significant decrease in BNP levels at the first follow-up visit (45-60 days) compared to baseline measurements (759.90 pg ml(-1) vs. 636.90 pg ml(-1) , P = 0.013). CONCLUSIONS: Left atrial appendage occlusion modifies BNP levels. These levels decrease after left atrial appendage occlusion. The clinical consequences of these findings need to be evaluated in further studies. © 2015 Wiley Periodicals, Inc.

Conceptual and numerical modeling of radionuclide transport and retention in near-surface systems.

Scenarios of barrier failure and radionuclide release to the near-surface environment are important to consider within performance and safety assessments of repositories for nuclear waste. A geological repository for spent nuclear fuel is planned at Forsmark, Sweden. Conceptual and numerical reactive transport models were developed in order to assess the retention capacity of the Quaternary till and clay deposits for selected radionuclides, in the event of an activity release from the repository. The elements considered were carbon (C), chlorine (Cl), cesium (Cs), iodine (I), molybdenum (Mo), niobium (Nb), nickel (Ni), radium (Ra), selenium (Se), strontium (Sr), technetium (Tc), thorium (Th), and uranium (U). According to the numerical predictions, the repository-derived nuclides that would be most significantly retained are Th, Ni, and Cs, mainly through sorption onto clays, followed by U, C, Sr, and Ra, trapped by sorption and/or incorporation into mineral phases.

Modelling geochemical and microbial consumption of dissolved oxygen after backfilling a high level radiactive waste repository.

Dissolved oxygen (DO) left in the voids of buffer and backfill materials of a deep geological high level radioactive waste (HLW) repository could cause canister corrosion. Available data from laboratory and in situ experiments indicate that microbes play a substantial role in controlling redox conditions near a HLW repository. This paper presents the application of a coupled hydro-bio-geochemical model to evaluate geochemical and microbial consumption of DO in bentonite porewater after backfilling of a HLW repository designed according to the Swedish reference concept. In addition to geochemical reactions, the model accounts for dissolved organic carbon (DOC) respiration and methane oxidation. Parameters for microbial processes were derived from calibration of the REX in situ experiment carried out at the Aspö underground laboratory. The role of geochemical and microbial processes in consuming DO is evaluated for several scenarios. Numerical results show that both geochemical and microbial processes are relevant for DO consumption. However, the time needed to consume the DO trapped in the bentonite buffer decreases dramatically from several hundreds of years when only geochemical processes are considered to a few weeks when both geochemical reactions and microbially-mediated DOC respiration and methane oxidation are taken into account simultaneously.

Large-scale modeling of reactive solute transport in fracture zones of granitic bedrocks.

Final disposal of high-level radioactive waste in deep repositories located in fractured granite formations is being considered by several countries. The assessment of the safety of such repositories requires using numerical models of groundwater flow, solute transport and chemical processes. These models are being developed from data and knowledge gained from in situ experiments such as the Redox Zone Experiment carried out at the underground laboratory of Aspö in Sweden. This experiment aimed at evaluating the effects of the construction of the access tunnel on the hydrogeological and hydrochemical conditions of a fracture zone intersected by the tunnel. Most chemical species showed dilution trends except for bicarbonate and sulphate which unexpectedly increased with time. Molinero and Samper [Molinero, J. and Samper, J. Groundwater flow and solute transport in fracture zones: an improved model for a large-scale field experiment at Aspö (Sweden). J. Hydraul. Res., 42, Extra Issue, 157-172] presented a two-dimensional water flow and solute transport finite element model which reproduced measured drawdowns and dilution curves of conservative species. Here we extend their model by using a reactive transport which accounts for aqueous complexation, acid-base, redox processes, dissolution-precipitation of calcite, quartz, hematite and pyrite, and cation exchange between Na+ and Ca2+. The model provides field-scale estimates of cation exchange capacity of the fracture zone and redox potential of groundwater recharge. It serves also to identify the mineral phases controlling the solubility of iron. In addition, the model is useful to test the relevance of several geochemical processes. Model results rule out calcite dissolution as the process causing the increase in bicarbonate concentration and reject the following possible sources of sulphate: (1) pyrite dissolution, (2) leaching of alkaline sulphate-rich waters from a nearby rock landfill and (3) dissolution of iron monosulphides contained in Baltic seafloor sediments. Based on these results, microbially mediated processes are postulated as the most likely hypothesis to explain the measured increase of dissolved bicarbonates and sulphates after tunnel construction.