Modelling of the long-term evolution and performance of engineered barrier system

Components of the so-called “multiple-barrier system” from the waste form to the biosphere include a combination of waste containers, engineered barriers, and natural barriers. The Engineered Barrier System (EBS) is crucial for containment and isolation in a radioactive waste disposal system. The number, types, and assigned safety functions of the various engineered barriers depend on the chosen repository concept, the waste form, the radionuclides waste inventory, the selected host rock, and the hydrogeological and geochemical settings of the repository site, among others. EBS properties will evolve with time in response to the thermal, hydraulic, mechanical, radiological, and chemical gradients and interactions between the various constituents of the barriers and the host rock. Therefore, assessing how these properties evolve over long time frames is highly relevant for evaluating the performance of a repository system and safety function evaluations in a safety case. For this purpose, mechanistic numerical models are increasingly used. Such models provide an excellent way for integrating into a coherent framework a scientific understanding of coupled processes and their consequences on different properties of the materials in the EBS. Their development and validation are supported by R&D actions at the European level. For example, within the HORIZON 2020 project BEACON (Bentonite mechanical evolution), the development, test, and validation of numerical models against experimental results have been carried out in order to predict the evolution of the hydromechanical properties of bentonite during the saturation process. Also, in relation to the coupling with mechanics, WP16 MAGIC (chemo Mechanical AGIng of Cementitious materials) of the EURAD Joint Programming Initiative focuses on multi-scale chemo-mechanical modeling of cementitious-based materials that evolve under chemical perturbation. Integration of chemical evolution in models of varying complexity is a major issue tackled in the WP2 ACED (Assessment of Chemical Evolution of ILW and HLW Disposal cells) of EURAD. WP4 DONUT (Development and improvement of numerical methods and tools for modeling coupled processes) of EURAD aims at developing and improving numerical models and tools to integrate more complexity and coupling between processes. The combined progress of those projects at a pan-European level definitively improves the understanding of and the capabilities for assessing the long-term evolution of engineered barrier systems.

Clinical, computed tomographic, surgical findings and outcome in dogs with sublumbar abscessation: 16 cases (2013 to 2019)

OBJECTIVES

To describe the clinical presentation, CT imaging findings, surgical treatment and long-term outcome in dogs with sublumbar abscessation.

MATERIALS AND METHODS

Medical records of dogs treated for sublumbar abscessation between 2013 and 2019 were retrieved. Criteria for inclusion were a diagnosis of sublumbar abscessation, complete patient history, pre-operative CT imaging, blood work, bacteriology results, record of the surgical treatment, post-operative care and outcome.

RESULTS

Sixteen dogs were included in this study with a median follow-up period of 36 months (15/16). Clinicals signs included flank or lumbar soft tissue swelling (12/16), lumbar pain (11/16), hyperthermia (8/16), a cutaneous discharging sinus (5/16) and lethargy (5/16). CT findings were: abscesses of varying size localised in the psoas muscles (16/16), spondylitis (12/16), vertebral osteomyelitis (6/16), discospondylitis (2/16) and epidural inflammation (8/16). Thoracic lesions were present in eight of 12 dogs. Exploratory surgery was performed in 16 dogs via a midline celiotomy in 15 of 16 and a lateral approach in one of 16 cases. The surgical approach was selected based on the location of the draining tracts detected on CT imaging. Vertebral body curettage was performed in five of 16 cases with lesions identified on CT. Vegetal foreign material was found in seven of 16 dogs. Of the 15 animals with long-term follow-up, 13 had no signs of recurrence.

CLINICAL SIGNIFICANCE

Surgical treatment of sublumbar abscessation resulted in a good long-term outcome when CT was used to guide the surgical approach and to plan the procedure. Our study highlights common vertebral and epidural lesions associated with sublumbar abscesses with a prevalence of 87.5%.

Fate and transport in environmental quality

Changes in pollutant concentrations in environmental media occur both from pollutant transport in water or air and from local processes, such as adsorption, degradation, precipitation, straining, and so on. The terms "fate and transport" and "transport and fate" reflect the coupling of moving with the carrier media and biogeochemical processes describing local transformations or interactions. The Journal of Environmental Quality (JEQ) was one of the first to publish papers on fate and transport (F&T). This paper is a minireview written to commemorate the 50th anniversary of JEQ and show how the research interests, methodology, and public attention have been reflected in fate and transport publications in JEQ during the last 40 years. We report the statistics showing how the representation of different pollutant groups in papers changed with time. Major focus areas have included the effect of solution composition on F&T and concurrent F&T, the role of organic matter, and the relative role of different F&T pathways. The role of temporal and spatial heterogeneity has been studied at different scales. The value of long-term F&T studies and developments in modeling as the F&T research approach was amply demonstrated. Fate and transport studies have been an essential part of conservation measure evaluation and comparison and ecological risk assessment. For 50 years, JEQ has delivered new insights, methods, and applications related to F&T science. The importance of its service to society is recognized, and we look forward to new generations of F&T researchers presenting their contributions in JEQ.

Coupling Flow, Heat, and Reactive Transport Modeling to Reproduce In Situ Redox Potential Evolution: Application to an Infiltration Pond

Redox potential (Eh) measurements are widely used as indicators of the dominant reduction-oxidation reactions occurring underground. Yet, Eh data are mostly used in qualitative terms, as actual values cannot be used to distinguish uniquely the dominant redox processes at a sampling point and should therefore be combined with a detailed geochemical characterization of water samples. In this work, we have intensively characterized the redox potential of the first meter of soil in an infiltration pond recharged with river water using a set of in situ sensors measuring every 12 min during a 1 year period. This large amount of data combined with hydrogeochemical campaigns allowed developing a reactive transport model capable of reproducing the redox potential in space and time together with the site hydrochemistry. Our results showed that redox processes were mainly driven by the amount of sedimentary organic matter in the system as well as by seasonal variation of temperature. As a subsidiary result, our work emphasizes the need to use a fully coupled model of flow, heat transport, solute transport, and the geochemical reaction network to fully reproduce the Eh observations in the topsoil.

Sterilisation of intellectually disabled women

Objective

To point out the proportion of intellectually disabled women (IDW) who are sterilised, and the medical and social factors associated with an increased probability to be sterilised.

Study design

A population-based study among 97% of IDW aged 18–46, attending government-accredited institutions in the region of Brussels-Capital and the province of Walloon Brabant (Belgium).

Results

Among the IDW included in this study, 22.2% are sterilised, which is superior to the 7% in the general Belgian population. Factors associated with an increased probability to be sterilised are: living in an institution, having a higher intellectual quotient (IQ), being enrolled in an institution where sexual intercourse is authorised and attending an institution where contraception is required. The last three factors are significant only among women living in institutions and the last two, only in women with severe disability. Among IDW using contraception, no factor was associated with a greater probability to be sterilised.

Conclusion

The prevalence of sterilisation among IDW is three times higher than that in the Belgian population and it is mainly correlated with factors related to the institution where these women live, especially the severely disabled.

Nested multiresolution hierarchical simulated annealing algorithm for porous media reconstruction

Microstructure strongly influences flow and transport properties of porous media. Flow and transport simulations within porous media, therefore, requires accurate three-dimensional (3D) models of the pore and solid phase structure. To date, no imaging method can resolve all relevant heterogeneities from the nano- to the centimeter scale within complex heterogeneous materials such as clay, reservoir rocks (e.g., travertine, chalk, ...), hardened cement paste, and concrete. To reconstruct these porous materials it is thus necessary to merge information from different 2D and potentially 3D imaging methods. One porous media reconstruction methodology that has been around for at least two decades is simulated annealing (SA). However, realizations with SA typically suffer an artificially reduced long-range connectivity, while multiphase reconstructions are not feasible in most cases because of a prohibitive computational burden. To solve these problems we propose a hierarchical multiresolution and multiphase simulated annealing algorithm. To decrease the computational cost of multiphase simulation, our algorithm sequentially simulates one phase after another, in a hierarchical way, which enables handling multimodal distributions and topological relations. Building upon recent work, our algorithm improves long-range connectivity and CPU efficiency by simulating larger particles using a coarser resolution that is subsequently refined compared to standard SA; our proposed extension not only offers the possibility to perform multiphase reconstruction but also allows us (i) to improve binary reconstruction quality, as quantified, e.g., by multiple-point histograms by up to one order of magnitude and (ii) to achieve an overall speed-up. The proposed algorithm is also shown to outperform the direct sampling multiple-point statistics method for the generation of cement paste microstructure with respect to both generation time and quality.

Numerically accelerated pore-scale equilibrium dissolution

Simulation of dissolution processes with a pore-scale reactive transport model increases insight in coupled chemical-physical-transport processes. However, modelling of dissolution process often requires a large number of time steps especially when the buffering capacity of solid phases is high. In this work we analyze the interplay between solid buffering on one hand and transport on the other. Based on this analysis we propose an approach to reduce the number of required time steps for simulating equilibrium dissolution processes. The underlying idea is that the number of time step iterations can be reduced if the buffering is sufficient to bring the system to a steady state, i.e. that the concentration field around solid is time-invariant. If this condition is satisfied, then it is possible to reduce the physical (and thus also computational) time by adjusting the chemical system appropriately. First we derived a dimensionless value - called buffering number - to determine under which conditions reduction in time can be made. Several examples illustrate that below a certain buffering number, the physical time can be reduced without significant effect on result (e.g. dissolution front) as long as the solid volume fraction is sufficient. This means that for a given solid-liquid system, the calculation time can be reduced either by the reduction of mass in solid or by the increase of equilibrium concentration (solubility). We also show that the calculation time for calcium leaching in cementitious systems can be reduced by 50 times with a negligible error.

Transport of dissolved organic matter in Boom Clay: Size effects

A coupled experimental-modelling approach was developed to evaluate the effects of molecular weight (MW) of dissolved organic matter (DOM) on its transport through intact Boom Clay (BC) samples. Natural DOM was sampled in-situ in the BC layer. Transport was investigated with percolation experiments on 1.5cm BC samples by measuring the outflow MW distribution (MWD) by size exclusion chromatography (SEC). A one-dimensional reactive transport model was developed to account for retardation, diffusion and entrapment (attachment and/or straining) of DOM. These parameters were determined along the MWD by implementing a discretisation of DOM into several MW points and modelling the breakthrough of each point. The pore throat diameter of BC was determined as 6.6-7.6nm. Below this critical size, transport of DOM is MW dependent and two major types of transport were identified. Below MW of 2kDa, DOM was neither strongly trapped nor strongly retarded. This fraction had an averaged capacity factor of 1.19±0.24 and an apparent dispersion coefficient ranging from 7.5×10^-11 to 1.7× 10^-11m²/s with increasing MW. DOM with MW>2kDa was affected by both retardation and straining that increased significantly with increasing MW while apparent dispersion coefficients decreased. Values ranging from 1.36 to 19.6 were determined for the capacity factor and 3.2×10^-11 to 1.0×10^-11m²/s for the apparent dispersion coefficient for species with 2.2kDa<MW<9.3kDa. Straining resulted in an immobilisation of in average 49±6% of the injected 9.3kDa species. Our findings show that an accurate description of DOM transport requires the consideration of the size effects.

Clinical Study of Fetal Mesencephalic Intracerebral Transplants for the Treatment of Parkinson's Disease

This study reports our findings from 22 patients (ages ranging from 42 to 73 yr; mean = 55.2) with recalcitrant idiopathic Parkinson's disease (PD) who received implants of fetal ventral mesencephalic tissue using an MRI-guided stereotactic procedure and who have been followed for at least 6 mo postoperatively, employing the guidelines established by the Core Assessment Program for Intracerebral Transplantations. Evaluations were videotaped and were performed both on and off levodopa medications. To date, we have seven patients with 24 mo, three with 18 mo, three with 12 mo, and nine with 6 mo of postsurgical assessments. Comparing surgical outcomes to levels prior to fetal transplants we found: 1) mean levodopa levels were reduced 46% at 6 mo, 12% at 12 mo, 20% at 18 mo, and 54% at 24 mo; 2) Unified Parkinson's Disease Rating Scale (UPDRS) scores with patients on levodopa were improved by an average of 38% (6 mo), 50.2% (12 mo), 69.3% (18 mo), and 73.9% (24 mo), while off medication scores showed reductions ranging from 24.7% at 6 mo to 55.1% at 24 mo. Other measures, including Hoehn-Yahr staging, Activities of Daily Living, and dyskinesia rating scales, were also significantly improved following fetal transplants. Timed motor tasks (finger dexterity, supination-pronation, foot tapping, and Stand-Walk-Sit) performance also demonstrated highly significant improvements. Patient's self-rating scores indicated that the patients typically perceived substantial improvements in their condition. However, substantial variability in the improvements following surgery still persists and range from nominal improvements in performance to significant changes that can be classified as altering the overall lifestyle of the patients. To date, 4 of the 22 subjects were considered by the physicians to be nonresponders; that is, there were no clinically relevant improvements in these patients' conditions.

Experimental and Numerical Investigations of Silver Nanoparticle Transport under Variable Flow and Ionic Strength in Soil

Unsaturated column experiments were conducted with an undisturbed loamy sand soil to investigate the influence of flow interruption (FI) and ionic strength (IS) on the transport and retention of surfactant-stabilized silver nanoparticles (AgNP) and the results were compared to those obtained under continuous flow conditions. AgNP concentrations for breakthrough curves (BTCs) and retention profiles (RPs) were analyzed by ICP-MS. Experimental results were simulated by the numerical code HP1 (Hydrus-PhreeqC) with the DLVO theory, extended colloid filtration theory and colloid release model. BTCs of AgNP showed a dramatic drop after FI compared to continuous flow conditions. Evaporation increased due to FI, resulting in increased electrical conductivity of the soil solution, which led to a totally reduced mobility of AgNP. A reduction of IS after FI enhanced AgNP mobility slightly. Here the strongly increased Al and Fe concentration in the effluent suggested that soil colloids facilitated the release of AgNP (cotransport). The numerical model reproduced the measured AgNP BTCs and indicated that attachment to the air-water interface (AWI) occurring during FI was the key process for AgNP retention.

Impact of manure-related DOM on sulfonamide transport in arable soils

Field application of livestock manure introduces colloids and veterinary antibiotics, e.g. sulfonamides (SAs), into farmland. The presence of manure colloids may potentially intensify the SAs-pollution to soils and groundwater by colloid-facilitated transport. Transport of three SAs, sulfadiazine (SDZ), sulfamethoxypyridazine (SMPD), and sulfamoxole (SMOX), was investigated in saturated soil columns with and without manure colloids from sows and farrows, weaners, and fattening pigs. Experimental results showed that colloid-facilitated transport of SMOX was significant in the presence of manure colloids from fattening pigs with low C/N ratio, high SUVA280nm and protein C, while manure colloids from sows and farrows and weaners had little effect on SMOX transport. In contrast, only retardation was observed for SDZ and SMPD when manure colloids were present. Breakthrough curves (BTCs) of colloids and SAs were replicated well by a newly developed numerical model that considers colloid-filtration theory, competitive kinetic sorption, and co-transport processes. Model results demonstrate that mobile colloids act as carriers for SMOX, while immobile colloids block SMOX from sorbing onto the soil. The low affinity of SMOX to sorb on immobile colloids prevents aggregation and also promotes SMOX's colloid-facilitated transport. Conversely, the high affinity of SDZ and SMPD to sorb on all types of immobile colloids retarded their transport. Thus, manure properties play a fundamental role in increasing the leaching risk of hydrophobic sulfonamides.

A reactive transport model for mercury fate in contaminated soil--sensitivity analysis

We present a sensitivity analysis of a reactive transport model of mercury (Hg) fate in contaminated soil systems. The one-dimensional model, presented in Leterme et al. (2014), couples water flow in variably saturated conditions with Hg physico-chemical reactions. The sensitivity of Hg leaching and volatilisation to parameter uncertainty is examined using the elementary effect method. A test case is built using a hypothetical 1-m depth sandy soil and a 50-year time series of daily precipitation and evapotranspiration. Hg anthropogenic contamination is simulated in the topsoil by separately considering three different sources: cinnabar, non-aqueous phase liquid and aqueous mercuric chloride. The model sensitivity to a set of 13 input parameters is assessed, using three different model outputs (volatilized Hg, leached Hg, Hg still present in the contaminated soil horizon). Results show that dissolved organic matter (DOM) concentration in soil solution and the binding constant to DOM thiol groups are critical parameters, as well as parameters related to Hg sorption to humic and fulvic acids in solid organic matter. Initial Hg concentration is also identified as a sensitive parameter. The sensitivity analysis also brings out non-monotonic model behaviour for certain parameters.

A reactive transport model for mercury fate in soil--application to different anthropogenic pollution sources

Soil systems are a common receptor of anthropogenic mercury (Hg) contamination. Soils play an important role in the containment or dispersion of pollution to surface water, groundwater or the atmosphere. A one-dimensional model for simulating Hg fate and transport for variably saturated and transient flow conditions is presented. The model is developed using the HP1 code, which couples HYDRUS-1D for the water flow and solute transport to PHREEQC for geochemical reactions. The main processes included are Hg aqueous speciation and complexation, sorption to soil organic matter, dissolution of cinnabar and liquid Hg, and Hg reduction and volatilization. Processes such as atmospheric wet and dry deposition, vegetation litter fall and uptake are neglected because they are less relevant in the case of high Hg concentrations resulting from anthropogenic activities. A test case is presented, assuming a hypothetical sandy soil profile and a simulation time frame of 50 years of daily atmospheric inputs. Mercury fate and transport are simulated for three different sources of Hg (cinnabar, residual liquid mercury or aqueous mercuric chloride), as well as for combinations of these sources. Results are presented and discussed with focus on Hg volatilization to the atmosphere, Hg leaching at the bottom of the soil profile and the remaining Hg in or below the initially contaminated soil layer. In the test case, Hg volatilization was negligible because the reduction of Hg(2+) to Hg(0) was inhibited by the low concentration of dissolved Hg. Hg leaching was mainly caused by complexation of Hg(2+) with thiol groups of dissolved organic matter, because in the geochemical model used, this reaction only had a higher equilibrium constant than the sorption reactions. Immobilization of Hg in the initially polluted horizon was enhanced by Hg(2+) sorption onto humic and fulvic acids (which are more abundant than thiols). Potential benefits of the model for risk management and remediation of contaminated sites are discussed.

Determination of 137Cs contamination depth distribution in building structures using geostatistical modeling of ISOCS measurements

Decommissioning of nuclear building structures usually leads to large amounts of low level radioactive waste. Using a reliable method to determine the contamination depth is indispensable prior to the start of decontamination works and also for minimizing the radioactive waste volume and the total workload. The method described in this paper is based on geostatistical modeling of in situ gamma-ray spectroscopy measurements using the multiple photo peak method. The method has been tested on the floor of the waste gas surge tank room within the BR3 (Belgian Reactor 3) decommissioning project and has delivered adequate results.

Inverse optimization of hydraulic, solute transport, and cation exchange parameters using HP1 and UCODE to simulate cation exchange

Reactive transport modeling is a powerful tool to evaluate systems with complex geochemical relations. However, parameters are not always directly measurable. This study represents one of the first attempts to obtain hydrologic, transport and geochemical parameters from an experimental dataset involving transient unsaturated water flow and solute transport, using an automatic inverse optimization (or calibration) algorithm. The data come from previously published, controlled laboratory experiments on the transport of major cations (Na, K, Mg, Ca) during water absorption into horizontal soil columns that were terminated at different times. Experimental data consisted of the depth profiles of water contents (θ), Cl concentrations, and total aqueous and sorbed concentrations of major cations. The dataset was used to optimize several parameters using the reactive transport model, HP1 and the generic optimization code, UCODE. Although the soil hydraulic and solute transport parameters were also optimized, the study focused mainly on the geochemical parameters because the soil columns were constructed from disturbed soil. The cation exchange capacity and the cation exchange coefficients for two exchange models (Gapon and Rothmund-Kornfeld) were optimized. The results suggest that both calibrated models satisfactorily described the experimental data, although the Rothmund-Kornfeld model fit was slightly better. However, information content and surface response analyses indicated that parameters of the Gapon model are well identifiable, whereas those of the Rothmund-Kornfeld model were strongly correlated. The calibrated geochemical parameters were validated using an independent dataset. In agreement with the identifiability analysis, the Gapon approach was better than the Rothmund-Kornfeld model at calculating the observed concentrations of major cations in the soil solution and on the exchange sites.

Determining hydraulic properties of concrete and mortar by inverse modelling

This paper presents a methodology and results on estimating hydraulic properties of the concrete and mortar considered for the near surface disposal facility in Dessel, Belgium, currently in development by ONDRAF/NIRAS. In a first part, we estimated the van parameters for the water retention curve for concrete and mortar obtained by calibration (i.e. inverse modelling) of the van Genuchten model [1] to experimental water retention data [2]. Data consisted of the degree of saturation measured at different values of relative humidity. In the second part, water retention data and data from a capillary suction experiment on concrete and mortar cores was used jointly to successfully determine the van Genuchten retention parameters and the Mualem hydraulic conductivity parameters (including saturated hydraulic conductivity) by inverse modelling.

Thermal slip sources at the extremity and bevel edge of silicon wafers

High-resolution X-ray diffraction imaging of 200 mm silicon wafers following rapid thermal annealing at a temperature of 1270 K has revealed the presence of many early stage sources of thermal slip associated with the wafer edge. Dislocation sources are primarily at the wafer extremity, though many are generated by damage at the edge of the bevel incline on the wafer surface. A smaller fraction of sources is associated with other regions of localized damage, probably relating to protrusions on the wafer support. The geometry of the latter is similar to that of dislocation sources generated by controlled indentation on the wafer surface. It is concluded that rapid spike annealing at high temperature does not suppress the nucleation of slip, but rather the rapidity of the process prevents the propagation of the dislocations in the slip band into the wafer.

Modelling uranium leaching from agricultural soils to groundwater as a criterion for comparison with complementary safety indicators

Naturally occurring radionuclides can also end up in soils and groundwater due to human practices, such as application of certain fertilizers in agriculture. Many mineral fertilizers, particularly (super)phosphates, contain small amounts of 238U and 230Th which eventually may be leached from agricultural soils to underlying water resources. Field soils that receive P-fertilizers accumulate U and Th and their daughter nuclides, which eventually may leach to groundwater. Our objective was to numerically assess U migration in soils. Calculations were based on a new reactive transport model, HP1, which accounts for interactions between U and organic matter, phosphate, and carbonate. Solid phase interactions were simulated using a surface complexation module. Furthermore, all geochemical processes were coupled with a model accounting for dynamic changes in the soil water content and the water flux. The capabilities of the code in calculating natural U fluxes to groundwater were illustrated using a semi-synthetic 200-year long time series of climatological data for Belgium. Based on an average fertilizer application, the input of phosphate and uranium in the soil was defined. This paper discusses calculated U distributions in the soil profile as well as calculated U fluxes leached from a 100-cm deep soil profile. The calculated long-term leaching rates originating from fertilization are significantly higher after 200 years than estimated release rates from lowlevel nuclear waste repositories.

PHREEQC Modelling of Leaching of Major Elements and Heavy Metals From Cementitious Waste Forms

In this study, Ca, Mg, Al, and Pb concentrations leached from uncarbonated and carbonated ordinary Portland cement – dried waste incinerator bottom ash samples during single extraction tests (EN12457 test) at a pH from 1 to 12, were modelled using the geochemical code PHREEQC. A good agreement was found between modelling results and experiments in terms of leached concentrations for Ca, Mg, and Al by defining a single set of pure mineralogical phases for both the uncarbonated and carbonated (three levels) samples. The model also predicted well the observed decrease in Ca leaching with increasing carbonation. Modelling results further revealed that leaching of Pb is not controlled by dissolution/precipitation of pure Pb containing minerals only (carbonates and (hydr)oxides). The addition of solid solutions (calcite-cerrusite and gibbsite-ferrihydrite-litharge solid solutions) and adsorption reactions on amorphous Fe- and Al-oxides improved the model representation of the experimentally observed amphoteric leaching profile of Pb from the cementitious material.

Dislocation sources and slip band nucleation from indents on silicon wafers

The nucleation of dislocations at controlled indents in silicon during rapid thermal annealing has been studied byin situX-ray diffraction imaging (topography). Concentric loops extending over pairs of inclined {111} planes were formed, the velocities of the inclined and parallel segments being almost equal. Following loss of the screw segment from the wafer, the velocity of the inclined segments almost doubled, owing to removal of the line tension of the screw segments. The loops acted as obstacles to slip band propagation.

Comparisons between psychotropic drugs: must the risk of side effects dictate our practices?

OBJECTIVES

Recently, SOHO and CATIE's studies in the field of schizophrenic disorders asserted that molecules apparently showing the most side-effects are not only the most effective but also lead to the least changes in treatments. Can we generalise this assertion to other domains of pharmacological treatments, such as in mood and anxiety disorders? And, more generally, do we possess information about comparison between different types of molecules in these different fields.

METHODS

Review of the literature (medline-psycinfo-psycarticles) addressing these three psychiatric disorders, and comparing efficacy of treatments, or cost-effectiveness studies.

RESULTS

Although there is a plethora of publications about the efficacy of given molecules vs. placebo, studies comparing molecules are scarce, and studies on cost-effectiveness in natural environments are even more scarce. Independently of the type of disorders under study, the last few years' efforts to completely limit side effects seem to have resulted in a loss of efficacy. Moreover, the previously held hypothesis suggesting that the fewer the side effects, the lesser the need to change treatment has not been confirmed. The duration of a treatment is more dependent upon its efficacy than on other variables.

CONCLUSIONS

Clinicians cannot determine the absence of noxiousness of a molecule as their primary criterion of choice. In contrast, they should carefully balance side effects and efficacy. In Psychiatry, there is a lack of studies about cost-effectiveness in natural environments.

Respiratory variations in pulse oximeter waveform amplitude are influenced by venous return in mechanically ventilated patients under general anaesthesia

BACKGROUND AND OBJECTIVES

Respiratory variations in pulse oximetry plethysmographic waveform amplitude (DeltaPOP) are related to respiratory variations in arterial pulse pressure (DeltaPP) in the critical care setting. The aims of this study were to test the hypothesis that in mechanically ventilated patients undergoing general anaesthesia, DeltaPOP calculation is feasible and can detect changes in preload.

METHODS

Twenty-five mechanically ventilated patients were studied immediately after induction of general anaesthesia. Haemodynamic data (mean arterial pressure [MAP], central venous pressure [CVP], DeltaPP and DeltaPOP) were recorded at baseline, before and after tilting the patient from anti-Trendelenburg to Trendelenburg position in order to induce preload changes.

RESULTS

Change from anti-Trendelenburg to Trendelenburg position induced changes in MAP (58 +/- 9 to 67 +/- 10 mmHg, P < 0.05), CVP (4 +/- 4 to 13 +/- 5 mmHg, P < 0.05), DeltaPP (14 +/- 8 to 7 +/- 5%, P < 0.05) and DeltaPOP (17 +/- 12 to 9 +/- 5%, P < 0.05). There was a significant relationship between DeltaPOP in anti-Trendelenburg position and percent change in MAP after volume expansion (r = 0.82; P < 0.05).

CONCLUSIONS

DeltaPOP can be determined in the operating room and is influenced by changes in preload. This new index has potential clinical applications for the prediction of fluid responsiveness.

Operator-splitting errors in coupled reactive transport codes for transient variably saturated flow and contaminant transport in layered soil profiles

One possible way of integrating subsurface flow and transport processes with (bio)geochemical reactions is to couple by means of an operator-splitting approach two completely separate codes, one for variably-saturated flow and solute transport and one for equilibrium and kinetic biogeochemical reactions. This paper evaluates the accuracy of the operator-splitting approach for multicomponent systems for typical soil environmental problems involving transient atmospheric boundary conditions (precipitation, evapotranspiration) and layered soil profiles. The recently developed HP1 code was used to solve the coupled transport and chemical equations. For steady-state flow conditions, the accuracy was found to be mainly a function of the adopted spatial discretization and to a lesser extent of the temporal discretization. For transient flow situations, the accuracy depended in a complex manner on grid discretization, time stepping and the main flow conditions (infiltration versus evaporation). Whereas a finer grid size reduced the numerical errors during steady-state flow or the main infiltration periods, the errors sometimes slightly increased (generally less than 50%) when a finer grid size was used during periods with a high evapotranspiration demand (leading to high pressure head gradients near the soil surface). This indicates that operator-splitting errors are most significant during periods with high evaporative boundary conditions. The operator-splitting errors could be decreased by constraining the time step using the performance index (the product of the grid Peclet and Courant numbers) during infiltration, or the maximum time step during evapotranspiration. Several test problems were used to provide guidance for optimal spatial and temporal discretization.

[BNP/NT-proBNP: what is the best choice in an emergency laboratory?]

BNP and NT-proBNP are both well established as diagnostic and prognostic markers for congestive heart failure (CHF). However it remains for the biologist to choose between these two biomarkers depending on his equipment availability. The aim of this study was to compare results obtained with the Biosite Triage BNP assay and the Dade Behring NT-proBNP assay with regards to the clinical status. One hundred twelve patients (average age 76 +/- 13 years) with acute dyspnea were including and stratified by diagnosis at presentation into 3 groups: patients without acute CHF (group I, n=50), patients with non-cardiac dyspnea and CHF history (group II, n=22) and patients with acute CHF (group III, n=40). Levels of both BNP and NT-proBNP were higher among patients with cardiac dyspnea (group III) than among patients with a non-cardiac dyspnea (BNP=740 pg/mL versus 84 pg/mL; p<0.001 / NT-proBNP=7.502 pg/mL versus 499 pg/mL; p<0.001). ROC analysis for BNP or NT-proBNP were not statistically different in patients with acute CHF (group III) compared with patients with a non-cardiac dyspnea (group I + II) (AUC=0.927 versus AUC=0.930, p=0.90). Neither there was a difference between ROC analysis for BNP or NT-proBNP in patients with cardiac dyspnea (group III) compared to patients with a non cardiac dyspnea (group I) (AUC=0.981 versus AUC=0.975, p=0.76). Measurement of BNP or NT-proBNP is of identical interest for the diagnosis of acute CHF in acute dyspnea. The BNP Biosite assay was faster because analysis is performed on whole blood. With regards to analytical performance, the NT-proBNP Dade Behring assay had a higher accuracy and is highly recommended for the follow-up of CHF treatment.

[Alcoholism treatments]

The problem of the alcoholic dependence entails often dramatic consequences: problems of health, acts of violence, traffic accidents, absenteeism at work and lost of social insertion. The alcohol has on the other hand a sociocultural registration in our way of life often associated with conviviality. The alcoholism is often defined by some as a disease, by the others as a social plague. It also differs according to the forms which it takes, its previous history and the functions which it performs. What definition can we accept? What are the therapeutic options to be implemented? Some answers will be considered through condiderations on the concept of motivation to change.

Cancer prone persons. A randomized screening trial based on colonoscopy: background, design and recruitment

OBJECTIVE

Evidence-based counseling and prevention are not available so far for hereditary cancer prone persons, since we lack data based on clinical trials. There are very few high-risk persons in the population as a whole. Based on a familial history analysis, only 1.2% of all healthy volunteers attending screening centers reached the arbitrary high-risk level defined as a Relative Risk of more than 4. We describe a randomized trial based on colonoscopic screening for colorectal cancer on a sub-group of high-risk group persons.

MATERIALS AND METHODS

Among the 77 members of the French Institutional Preventive Center Network, 37 took part in this protocol. During the first 3 years, 850,000 persons were interviewed at these 37 Health centers. The enrollment process was particularly time-consuming, since a large amount of information had to be delivered to the participants.

RESULTS

The mean rate of recruitment of eligible candidates was far lower than predicted, averaging only 1.4 per 1,000 persons interviewed instead of the 9/1,000 expected. This mean figure was based, however, on inclusion rates ranging from 0.06/1,000 to 7/1,000 among the different centers. The low rates of recruitment were mainly due to the inter-center heterogeneity (differences in commitment and in the resources), and to the fact that the acceptability of undergoing a colonoscopy turned out to be lower than predicted.

CONCLUSION

Population trials on cancer prone persons are feasible, but vast numbers have to be pre- screened to identify the few people with a high hereditary risk and willing to accept screening within a controlled trial.

Enhanced mechanical properties of polyacrylonitrile/multiwall carbon nanotube composite fibers

The use of multiwall carbon nanotubes (MWNTs) as a reinforcing phase in a polyacrylonitrile (PAN) fiber matrix was investigated with the goal of producing a PAN-derived carbon/MWNT composite fiber with enhanced physical properties. MWNTs were dispersed in a PAN/DMAc (dimethylacetamide) solution and spun into composite fibers containing up to 5 wt.% MWNTs, with the use of a lab-scale dry-jet wet spinline. The spinning process resulted in alignment of the MWNTs parallel with the fiber axis. Three types of chemical vapor deposition (CVD)-derived, high-purity MWNTs were used: as produced, graphitized (heat treated to 2800 degrees C), and NaCN-treated (chemically treated to attach CN groups to the nanotube surface). Tensile tests were performed to measure yield stress/strain, initial modulus, break stress/strain, and energy to yield and energy to break. Significant mechanical property increases were recorded for the composite fibers compared with the control samples with no MWNT reinforcement: break strength +31%, initial modulus +36%, yield strength +46%, energy to yield +80%, and energy to break +83%.

Angiotensin II AT1 receptor internalization, translocation and de novo synthesis modulate cytosolic and nuclear calcium in human vascular smooth muscle cells

The present study was designed to verify if human (h) Angiotensin II (Ang II) type-1 receptor (hAT1R) undergoes internalization, nuclear translocation, and de novo synthesis in primary culture of human aortic vascular smooth muscle cells (hVSMCs) and if overexpression of this receptor modulates sustained free cytosolic ([Ca]c) and nuclear ([Ca]n) calcium. 3-dimensional (3-D) confocal microscopy was used to monitor free intracellular Ca2+ and hAT1R-green fluorescence protein (GFP) fusion protein in cultured hVSMCs. Immunofluorescence studies showed the presence of hAT1R and the absence of hAT2R in normal hVSMCs. Using 3-D imaging technique, hAT1 receptors were localized at the sarcolemma and in the cytosolic and nuclear compartments. In native as well as in normal hAT1R or hAT1R-GFP overexpressing hVSMCs, Ang II (10(-9) and 10(-4) M) induced internalization and nuclear translocation of this type of receptor. The internalization of hAT1Rs is mediated via clathrin-coated pits and vesicles pathway. This phenomenon of trancellular trafficking of receptors was associated with an increase of hAT1R. The Ang II induced increase of hAT1R density was prevented by the protein synthesis inhibitor cycloheximide. Overexpression of hAT1R and hAT1R-GFP decreased both basal cytosolic and nuclear Ca2+. In normal hVSMCs and low hAT1R-GFP overexpressing hVSMCs, Ang II (10(-15) to 10(-4) M) induced a dose-dependent sustained increase of [Ca]c and [Ca]n with an EC50 near 5 x 10(-11) and 5 x 10(-9) M, respectively. Our results suggest that hAT1Rs are the predominant type of Ang II receptors in aortic hVSMCs and are present in the sarcolemma, the cytosolic and the nuclear compartments. Ang II rapidly induces hAT1R internalization, nuclear translocation, as well as nuclear de novo synthesis of this receptor. The hAT1R overexpression in hVSMCs modulates sustained [Ca]c and [Ca]n.

Contraception of women with intellectual disability: prevalence and determinants

The contraception of women with intellectual disability (ID) is a major concern for caregivers. However, the prevalence of contraception and the frequency of use of different methods (e.g. sterilization) remain generally unknown. Moreover, indications specific to women with ID are controversial. The present authors conducted a population-based study among 97% of the women with ID aged between 18 and 46 years attending government-funded facilities in Brussels and the nearby province of Walloon Brabant in Belgium. Out of 397 subjects, 40.8% did not use any contraceptive method, 22.2% were sterilized, 18.4% used an oral contraceptive agent, 17.6% used depotmedroxyprogesterone acetate and 1% used an intrauterine device. These figures differ widely from those of the general Belgian population. Binary logistic regression for 'contraceptive utilization' showed the strong influence of institutional factors such as sleeping environment (i.e. institutional or parental), sexual relationship policy and contraception policy. Having or having had a boyfriend is also correlated with a stronger probability of contraceptive use. Other factors have a smaller influence (e.g. a milder level of ID). Very few factors, none of which are medical, are correlated with an increased use of a specific method. The present results are discussed in the light of the general medical application of contraception and the commonly assumed specific indications for women with ID.

Telemedicine: cost-effective management of high-risk pregnancy

PURPOSE

To evaluate the cost-effectiveness of telemedicine services in patients diagnosed with preterm labor (PTL).

DESIGN

Women hospitalized with a diagnosis of PTL during a 3-year study period were identified within a health maintenance organization.

INCLUSION CRITERIA

singleton gestation, stabilized after tocolysis and discharged from the hospital, and participation in the HMO's preterm-birth prevention program. After a PTL diagnosis, telemedicine services (home uterine activity monitoring with daily telephonic nursing contact) were authorized by the payer. The decision to prescribe telemedicine services was made by each patient's individual physician. Two groups of patients were identified: those who received telemedicine services (telemedicine group), and those who received standard care without the adjunctive outpatient service (control group).

METHODS

Descriptive and statistical methods were used to compare maternal demographics, pregnancy outcome, antepartum hospitalization, delivery, nursery, and outpatient services.

PRINCIPAL FINDINGS

One hundred women were identified: 60 in the telemedicine group and 40 in the control group. Gestational age at diagnosis of PTL was similar at 29.4 +/- 3.8 weeks, telemedicine group vs. 28.0 +/- 7.4 weeks, control group (P = 0.252). The telemedicine group had a significantly later mean gestational age at delivery (38.2 +/- 1.4 vs. 35.3 +/- 3.8), higher mean birth weight (3224 +/- 588 vs. 2554 +/- 911), fewer mean total nursery days (2.4 +/- 1.8 vs. 14.9 +/- 26.4), and less frequent admission to the neonatal intensive care unit (6.7 percent vs. 40 percent) than the control group (all P < 0.005). The total mean cost per pregnancy was $7,225 for the telemedicine group and $21,684 for the control group. This represented average savings of $14,459 per pregnancy using telemedicine services.

CONCLUSION

Following an episode of PTL, use of telemedicine services can be a cost-effective tool to improve pregnancy outcome.

Clinical and cost-effectiveness of continuous subcutaneous terbutaline versus oral tocolytics for treatment of recurrent preterm labor in twin gestations

OBJECTIVE

To compare the clinical and cost-effectiveness of treating recurrent preterm labor with continuous subcutaneous terbutaline versus oral tocolytics in twin gestations.

STUDY DESIGN

In a retrospective, matched-cohort design, twin pregnancies treated as outpatients with continuous subcutaneous terbutaline were identified from a perinatal database, then matched 1:1 by gestational age at recurrent preterm labor to those receiving oral tocolytics. There were 353 patients per treatment group. A cost model was used to compare antepartum hospital, nursery, and outpatient charges.

RESULTS

Infants of the subcutaneous terbutaline group had greater gestational age at delivery, higher birth weights, and less frequent neonatal intensive care unit admission. Charges for antepartum hospitalization and nursery were significantly less in the subcutaneous terbutaline group, while charges for outpatient services were less for the oral group. Mean total estimated charges were US$17,109 less for those receiving subcutaneous terbutaline.

CONCLUSION

Improved clinical outcomes and decreased nursery utilization suggest cost-effectiveness of outpatient continuous subcutaneous terbutaline versus oral tocolytics for the treatment of recurrent preterm labor.

Endothelin-1 regulates cytosolic and nuclear Ca2+ in human endocardial endothelium

Endocardial endothelium is far less studied than its systemic and pulmonary counterparts and its role in cardiac function is not well known. In the study reported here, we succeeded in isolating and culturing endocardial endothelial cells (EECs) from 21-week-old human fetal heart and verified whether endothelin-1 (ET-1) receptors are present on these cells and whether their activation regulates cytosolic ([Ca]c) and nuclear calcium ([Ca]n). Using fluo-3 Ca2+ measurement and three-dimension confocal microscopy techniques, superfusion of fetal human EECs from right and left ventricles with increasing concentrations of ET-1 induced a dose-dependent sustained increase of free cytosolic and nuclear Ca2+ levels with an EC50 near 10(-10) M and 10(-11) M, respectively. The sustained increase of cytosolic and nuclear Ca2+ by ET-1 in both EEC preparations was completely blocked by the calcium chelator ethylene glycol-bis (beta-aminoethylether)-N,N,N',N'-tetra-acetic acid (EGTA) but was insensitive to the L-type Ca2+ channel blocker, nifedipine. The effect of ET-1 was prevented by the ET(A)-receptor antagonist BQ 123. However the ET(B)-receptor antagonist BQ 788 had no effect. Our results suggest that ET-1 receptors are present in human EECs and that their stimulation induces sustained Ca2+ influx through ET(A)-receptor stimulation of a nifedipine-insensitive Ca2+ channel, probably the R-type Ca2+ channel. The presence of Ca2+-dependent responses to ET-1 supports a possible modulatory role of the endocardial endothelium in myocardial functions.

Presence of functional endothelin-1 receptors in nuclear membranes of human aortic vascular smooth muscle cells

Our previous work showed that the nucleus plays a role in excitation-contraction coupling and that the channels and receptors could be present at the nuclear membrane. In the study reported here, the objective was to test the hypothesis that endothelin-1 (ET-1) receptors are functional at the level of the nuclear membranes and that their stimulation importantly regulates free nucleoplasmic Ca2+ level. Using a Fluo-3 Ca2+ measurement technique in human vascular smooth muscle cells (HVSMC), superfusion with increasing concentrations of extracellular ET-1 induced a dose-dependent sustained increase of free cytosolic ([Ca]c), nuclear ([Ca]n) Ca2+ and contraction with an EC50 near 3 x 10(-10) M. Like the extracellular ET-1, the cytosolic application of ET-1 using the perforated sarcolemma membrane technique, induced a dose-dependent increase of nuclear free calcium of HVSMC with an EC50 of 2 x 10(-11) M. These results strongly suggest that ET-1 receptors are functional at the level of the nuclear membranes. Furthermore, the sensitivity of ET-1 receptors at the nuclear membrane level seems to be higher than that of the receptors at the sarcolemma membrane. Finally, our results suggest that cytosolic ET-1 may play a role in preventing HVSMC nuclear calcium overload, thus protecting the cells from apoptosis.

Nitric oxide relaxes the vascular smooth muscle independently of endothelin-1- and U46619-induced intracellular increase of calcium

A balance between circulating and locally released vasoconstrictors, such as endothelin-1 (ET-1), and vasodilators, such as nitric oxide, controls vascular smooth muscle tone. In the study reported here, using the technique of simultaneous measurements of intracellular free calcium ([Ca2+]i) and tension, we investigated the effects of a nitric oxide donor, sodium nitroprusside (NaNP) on endothelin-1- and U46619- [a thromboxane angiotensin-II (TXA-II) mimetic] induced sustained increases in tension and [Ca2+]i in intact and endothelium-denuded rabbit thoracic aortas. Our results showed that, in both intact and endothelium-denuded preparations, the nitric oxide donor NaNP (10(-6) M) reverses the ET-1- (10(-7) M) and U46619- (10(-7) M) induced sustained increase in tension but not in [Ca2+]i. However, it did not reduce the ET-1- and U46619-induced responses. Our data suggest that nitric oxide production modulates vascular smooth muscle tension via a mechanism that is independent of that generated by vasoconstrictors such as ET-1 and TXA-II.

A comparison of gestational days gained with oral terbutaline versus continuous subcutaneous terbutaline in women with twin gestations

OBJECTIVE

To compare gestational days gained with oral versus subcutaneous terbutaline for maintenance tocolysis.

STUDY DESIGN

In retrospective fashion 386 women enrolled in an outpatient preterm labor identification program met the following criteria: twin gestation, development of threatened preterm labor resulting in treatment with oral terbutaline, and subsequent recurrence of threatened preterm labor resulting in treatment with continuous subcutaneous terbutaline. The primary outcome was gestational days gained with oral terbutaline versus gain with continuous subcutaneous terbutaline.

RESULTS

There were significantly more days gained during subcutaneous treatment than during oral treatment (34.0 +/- 19.8 versus 19.3 +/- 15.3 days). Thirty-three percent of desired prolongation was achieved with oral terbutaline, whereas 79% of desired prolongation was achieved with subcutaneous terbutaline (p < 0.001). Patients gained a mean of 53.4 +/- 21.4 days overall with outpatient tocolysis. The mean gestational age at delivery was 35.2 +/- 1.9 weeks.

CONCLUSION

Continuous subcutaneous terbutaline was superior to oral terbutaline in prolonging gestation in women with twin gestations.

Weekly dosing of fluoxetine for the continuation phase of treatment of major depression: results of a placebo-controlled, randomized clinical trial

Fluoxetine (FLX) has a unique pharmacokinetic profile. Its major metabolite, norfluoxetine (NFLX), possesses FLX's antidepressant efficacy and a half-life of 7 to 15 days, suggesting the possibility of nonstandard dosing strategies. This study examined the tolerability of a weekly dose and its equivalence to daily dosing of FLX for the continuation phase of treatment for major depressive disorder (MDD). One hundred fourteen subjects initially received open-label treatment with 20 mg of FLX daily for 7 weeks. Subsequently, 70 subjects with a score on the Hamilton Rating Scale for Depression (HAM-D) of 12 or less were randomly assigned in a double-blind design to one of three treatment groups: 20 mg FLX daily (N = 21), 60 mg FLX weekly (N = 28), or placebo (N = 21) and were followed for 7 weeks. HAM-D scores and blood levels of FLX and NFLX were analyzed using a repeated-measures analysis of variance. During the double-blind phase, blood levels for both FLX and NFLX differed across the treatment groups, yet no statistically significant difference in HAM-D scores was observed. There was no difference in the dropout rate across the groups. Subjects could not correctly identify the treatment group into which they were assigned. Weekly dosing of FLX seems to be well tolerated and possibly as effective as daily dosing in maintaining the therapeutic response in subjects with MDD.

Neuropeptide Y induced increase of cytosolic and nuclear Ca2+ in heart and vascular smooth muscle cells

It was reported that neuropeptide Y (NPY) affects cardiac and vascular smooth muscle (VSM) function probably by increasing intracellular Ca2+. In this study, using fura-2 microfluorometry and fluo-3 confocal microscopy techniques for intracellular Ca2+ measurement, we attempted to verify whether the action of NPY receptor's stimulation in heart and VSM cells modulates intracellular Ca2+ and whether this effect is mediated via the Y1 receptor type. Using spontaneously contracting single ventricular heart cells of 10-day-old embryonic chicks and the fluo-3 confocal microscopy Ca2+ measurement technique to localize cytosolic ([Ca]c) and nuclear ([Ca]n) free Ca2+ level and distribution, 10-10 M of human (h) NPY significantly (P < 0.05) increased the frequency of cytosolic and nuclear Ca2+ transients during spontaneous contraction. Increasing the concentration of hNPY (10(-9) M) did not further increase the frequency of Ca2+ transients. The L-type Ca2+ channel blocker, nifedipine (10(-5) M), significantly (P < 0.001) blocked the spontaneous rise of intracellular Ca2+ in the absence and presence of hNPY (10(-10) and 10(-9) M). However, the selective Y1 receptor antagonist, BIBP3226 (10(-6) M), significantly decreased the hNPY-induced (10(-10) and 10(-9) M) increase in the frequency of Ca2+ transients back to near the control level (P < 0.05). In resting nonworking heart and human aortic VSM cells, hNPY induced a dose-dependent sustained increase of basal resting intracellular Ca2+ with an EC50 near 10(-9) M. This sustained increase was cytosolic and nuclear and was completely blocked by the Ca2+ chelator EGTA, and was significantly decreased by the Y1 receptor antagonist BIBP3226 in both heart (P < 0.05) and VSM (P < 0.01) cells. These results strongly suggest that NPY stimulates the resting basal steady-state Ca2+ influx through the sarcolemma and induces sustained increases of cytosolic and nuclear calcium, in good part, via the activation of the sarcolemma membrane Y1 receptor type in both resting heart and VSM cells. In addition, NPY also increased the frequency of Ca2+ transients during spontaneous contraction of heart cells mainly via the activation of the Y1 receptor type, which may explain in part the active cardiovascular action of this peptide.