Arsenic movement and fractionation in agricultural soils which received wastewater from an adjacent industrial site for 50 years

Arsenic (As) is an element with important environmental and human health implications due to its toxic properties. It is naturally occurring since it is contained in minerals, but it can also be enriched and distributed in the environment by anthropogenic activities. This paper reports on the historic As contamination of agricultural soils in one of the most important national relevance site for contamination in Italy, the so-called SIN Brescia-Caffaro, in the city of Brescia, northern Italy. These agricultural areas received As through the use of irrigation waters from wastewater coming from a factory of As-based pesticides (lead and calcium arsenates, sodium arsenite). Pesticide production started in 1920 and ended in the '70. Concentrations in the areas are generally beyond the legal threshold values for different soil uses and are up to >200 mg/kg. Arsenic contamination was studied to assess the long-time trend and the dynamics related to the vertical movement of As down to 1 m depth and its horizontal diffusion with surface irrigation in the entire field. Arsenic fractionation analysis (solid phase speciation by sequential extraction procedure) was also performed on samples collected from these areas and employed in greenhouse experiments with several plant species to evaluate the long-term contamination and the role of plant species in modifying As availability in soil. The results of this work can help in the evaluation of the conditions controlling the vertical transfer of As towards surface aquifers, the bioaccumulation likelihood in the agricultural food chain and the selection of sustainable remediation techniques such as phytoextraction

Single-Grain Virtualization for Contact Behavior Analysis on Sand

A methodology for virtualizing irregularly shaped grains is described here. The principle, largely inspired by computed tomography, is simple and accessible because only the three-dimensional (3D) outline of the grain is required. The volumetric object is obtained by reconstructing the planar projections of the grain acquired at different angles of rotation using a standard camera. Depending on the lens system, the resolution of the images can be as good as a few microns. A numerical representation of the real grain can be obtained by meshing the 3D image. The influence of grain morphology on the contact behavior of quartz sand is investigated here as an application of this novel technique. Numerical simulations using a finite-element model were carried out to reproduce the experimental data from normal compression single-grain tests. The results show the contribution of the initial grain rearrangement on the normal force-displacement response and its strong dependency on the shape of the grain. This study demonstrates that particle shape is a critical parameter for calibration of the contact behavior of sand

Absence of a dose-rate effect in the transformation of C3H 10T1/2 cells by α-particles

The findings of Hill et al. (1984) on the greatly enhanced transformation frequencies at very low dose rates of fission neutrons induced us to perform an analogous study with -particles at comparable dose rates. Transformation frequencies were determined with γ-rays at high dose rate (0·5 Gy/min), and with -particles at high (0·2 Gy/min) and at low dose rates (0·83-2·5 mGy/min) in the C3H 10T1/2 cell system. α-particles were substantially more effective than γ-rays, both for cell inactivation and for neoplastic transformation at high and low dose rates. The relative biological effectiveness (RBE) for cell inactivation and for neoplastic transformation was of similar magnitude, and ranged from about 3 at an -particle dose of 2 Gy to values of the order of 10 at 0·25 Gy. In contrast to the experiments of Hill et al. (1984) with fission neutrons, no increased transformation frequencies were observed when the -particle dose was protracted over several hours

Frictional properties of subduction input sediments at an erosive convergent continental margin and related controls on décollement slip modes - the Costa Rica Seismogenesis Project (CRISP)

The spectrum of slip modes occurring along shallow portions of the plate boundary décollement in subduction zones includes aseismic slip, slow slip, and seismogenic slip. The factors that control slip modes directly influence the hazard potential of subduction zones for generating large magnitude earthquakes and tsunamis. We conducted an experimental study of the frictional behaviour of subduction input sediments, recovered from two IODP expeditions to the erosive subduction margin offshore Costa Rica (Exp. 334, 344),employing rotary shear under hydrothermal conditions. The velocity dependence of friction was explored, using simulated gouges prepared from all major lithologies, covering a wide range of conditions representative for the initial stages of subduction. Temperature, effective normal stress, and pore fluid pressure were varied systematically up to 140 °C, 110 MPa and 120 MPa respectively. Sliding velocities up to 100 μm/s, relevant for earthquake rupture nucleation and slow slip, were investigated. The only sediment type that produced frictional instabilities (i.e. laboratory earthquakes) was the calcareous ooze carried by the incoming Cocos Plate, which by virtue of its slip weakening behaviour is also a likely candidate for triggering slow slip events. We evaluate this mechanism of producing unstable slip and consider alternatives. Therefore, locking and unlocking of plate boundary megathrusts are not only related to variations in pore fluid pressure, but may also depend on the presence of pelagic carbonate‐rich lithologies. Subduction systems containing such input are likely low‐latitude, where extensive deposition of carbonates takes place above the CCD

Evaluation of iron overload in nigrosome 1 via quantitative susceptibility mapping as a progression biomarker in prodromal stages of synucleinopathies

Idiopathic rapid eye movement (REM) sleep behavior disorder (iRBD) is a prodromal stage of α-synucleinopathies, such as Parkinson's disease (PD), which are characterized by the loss of dopaminergic neurons in substantia nigra, associated with abnormal iron load. The assessment of presymptomatic biomarkers predicting the onset of neurodegenerative disorders is critical for monitoring early signs, screening patients for neuroprotective clinical trials and understanding the causal relationship between iron accumulation processes and disease development. Here, we used Quantitative Susceptibility Mapping (QSM) and 7T MRI to quantify iron deposition in Nigrosome 1 (N1) in early PD (ePD) patients, iRBD patients and healthy controls and investigated group differences and correlation with disease progression. We evaluated the radiological appearance of N1 and analyzed its iron content in 35 ePD, 30 iRBD patients and 14 healthy controls via T2*-weighted sequences and susceptibility (χ) maps. N1 regions of interest (ROIs) were manually drawn on control subjects and warped onto a study-specific template to obtain probabilistic N1 ROIs. For each subject the N1 with the highest mean χ was considered for statistical analysis. The appearance of N1 was rated pathological in 45% of iRBD patients. ePD patients showed increased N1 χ compared to iRBD patients and HC but no correlation with disease duration, indicating that iron load remains stable during the early stages of disease progression. Although no difference was reported in iron content between iRBD and HC, N1 χ in the iRBD group increases as the disease evolves. QSM can reveal temporal changes in N1 iron content and its quantification may represent a valuable presymptomatic biomarker to assess neurodegeneration in the prodromal stages of PD

Clinical characteristics of a large cohort of patients with narcolepsy candidate for pitolisant: a cross-sectional study from the Italian PASS Wakix® Cohort

Introduction: Narcolepsy is a chronic and rare hypersomnia of central origin characterized by excessive daytime sleepiness and a complex array of symptoms as well as by several medical comorbidities. With growing pharmacological options, polytherapy may increase the possibility of a patient-centered management of narcolepsy symptoms. The aims of our study are to describe a large cohort of Italian patients with narcolepsy who were candidates for pitolisant treatment and to compare patients’ subgroups based on current drug prescription (drug-naïve patients in whom pitolisant was the first-choice treatment, switching to pitolisant from other monotherapy treatments, and adding on in polytherapy). Methods: We conducted a cross-sectional survey based on Italian data from the inclusion visits of the Post Authorization Safety Study of pitolisant, a 5-year observational, multicenter, international study. Results: One hundred ninety-one patients were enrolled (76.4% with narcolepsy type 1 and 23.6% with narcolepsy type 2). Most patients (63.4%) presented at least one comorbidity, mainly cardiovascular and psychiatric. Pitolisant was prescribed as an add-on treatment in 120/191 patients (62.8%), as switch from other therapies in 42/191 (22.0%), and as a first-line treatment in 29/191 (15.2%). Drug-naive patients presented more severe sleepiness, lower functional status, and a higher incidence of depressive symptoms. Conclusion: Our study presents the picture of a large cohort of Italian patients with narcolepsy who were prescribed with pitolisant, suggesting that polytherapy is highly frequent to tailor a patient-centered approach

The performance of stochastic designs in wellbore drilling operations

© 2018, The Author(s). Wellbore drilling operations frequently entail the combination of a wide range of variables. This is underpinned by the numerous factors that must be considered in order to ensure safety and productivity. The heterogeneity and sometimes unpredictable behaviour of underground systems increases the sensitivity of drilling activities. Quite often the operating parameters are set to certify effective and efficient working processes. However, failings in the management of drilling and operating conditions sometimes result in catastrophes such as well collapse or fluid loss. This study investigates the hypothesis that optimising drilling parameters, for instance mud pressure, is crucial if the margin of safe operating conditions is to be properly defined. This was conducted via two main stages: first a deterministic analysis—where the operating conditions are predicted by conventional modelling procedures—and then a probabilistic analysis via stochastic simulations—where a window of optimised operation conditions can be obtained. The outcome of additional stochastic analyses can be used to improve results derived from deterministic models. The incorporation of stochastic techniques in the evaluation of wellbore instability indicates that margins of the safe mud weight window are adjustable and can be extended considerably beyond the limits of deterministic predictions. The safe mud window is influenced and hence can also be amended based on the degree of uncertainty and the permissible level of confidence. The refinement of results from deterministic analyses by additional stochastic simulations is vital if a more accurate and reliable representation of safe in situ and operating conditions is to be obtained during wellbore operations.Published versio