The effect of changes in natural and anthropogenic deposition on modelling recovery from acidification

International audienceThe multi-layer dynamic soil chemistry SAFE model was used to study the dynamics of recovery in the F1 catchment at Lake Gårdsjön, Sweden. The influence of (1) sulphate adsorption, and (2) changes in marine deposition, on model predictions of recovery was studied. Sulphate adsorption/desorption in SAFE is modeled by an isotherm in which sulphate adsorption is dependent on both the sulphate concentration and the pH in the soil solution. This isotherm was parameterised for the B-horizon of F1 for the sulphate concentration range 10?260 m mol-1 and the pH range 3.8?5.0. Sulphate adsorption/desorption as the only soil process involving sulphate is adequate to predict sulphate in run-off at F1. Adding the process caused time-delays in sulphate concentration in run-off of only 1-2 years, which was much shorter than previously seen in the adjacent G1 catchment. The location of Lake Gårdsjön, approximately 15 km inland from the Swedish west coast, ensures that the marine deposition to the area is high. Model output showed that the temporal variation in marine deposition has a considerable impact on the run-off chemistry. Such changes in marine deposition are difficult to foresee and their influence on modelled run-off chemistry can be large when soils start to recover as the previously high concentrations of anthropogenic sulphate in the soil solution decrease. Keywords: climate change, dynamic modelling, run-off chemistry, sea-salt effect, soil and water acidification, sulphate adsorptio

The Mutational Profile of Unicystic Ameloblastoma

BRAF V600E is the most common mutation in conventional ameloblastoma (AM) of the mandible. In contrast, maxillary AMs appear to harbor more frequently RAS, FGFR2, or SMO mutations. Unicystic ameloblastoma (UAM) is considered a less aggressive variant of ameloblastoma, amenable to more conservative treatment, and classified as a distinct entity. The aim of this study was to characterize the mutation profile of UAM (n = 39) and to compare it to conventional AM (n = 39). The associations between mutation status and recurrence probability were also analyzed. In the mandible, 94% of UAMs (29/31, including 8/8 luminal, 6/8 intraluminal, and 15/15 mural subtypes) and 74% of AMs (28/38) revealed BRAF V600E mutations. Among the BRAF wild-type cases, 1 UAM showed a missense SMO mutation (p.L412F), whereas 2 NRAS (p.Q61R), 2 HRAS (p.Q61R), and 2 FGFR2 (p.C383R) activating mutations were identified in AM. Of the 3 maxillary UAMs, only 1 revealed a BRAF V600E mutation. Taken together, our findings demonstrate high frequency of activating BRAF V600E mutations in both UAM and AM of the mandible. In maxillary UAMs, the BRAF V600E mutation prevalence appears to be lower as was shown for AM previously. It could therefore be argued that UAM and AM are part of the spectrum of the same disease. AMs without BRAF V600E mutations were associated with an increased rate of local recurrence (P = 0.0003), which might indicate that routine mutation testing also has an impact on prognosis.Peer reviewe

European Society of Endodontology position statement: Management of deep caries and the exposed pulp

This position statement on the management of deep caries and the exposed pulp represents the consensus of an expert committee, convened by the European Society of Endodontology (ESE). Preserving the pulp in a healthy state with sustained vitality, preventing apical periodontitis and developing minimally invasive biologically based therapies are key themes within contemporary clinical endodontics. The aim of this statement was to summarize current best evidence on the diagnosis and classification of deep caries and caries‐induced pulpal disease, as well as indicating appropriate clinical management strategies for avoiding and treating pulp exposure in permanent teeth with deep or extremely deep caries. In presenting these findings, areas of controversy, low‐quality evidence and uncertainties are highlighted, prior to recommendations for each area of interest. A recently published review article provides more detailed information and was the basis for this position statement (Bjørndal et al. 2019, International Endodontic Journal, doi:10.1111/iej.13128). The intention of this position statement is to provide the practitioner with relevant clinical guidance in this rapidly developing area. An update will be provided within 5 years as further evidence emerges

Evaluation of model behaviour with respect to the biogeochemistry at the Solling spruce site

The performance and prediction of eleven biogeochemical models, applied to the time-series data from a spruce site in Solling, Germany, were evaluated. All the models are deterministic and process-oriented. They represent a wide range of modelling approaches with respect to time and space resolution and complexity. The evaluation showed that the general trends and levels in chemical variables, such as soil solution pH, concentrations of base cations, sulphate and aluminium, and base saturation can bereproduced by the models. Most models cannot correctly model pH and aluminium concentrations simultaneously

Response of six European forest sites to decided and proposed air pollution emission reductions

Two acid deposition scenarios were simulated for six European forest sites situated in Germany, Denmark, Russia, Switzerland, Spain and Ireland. Three models were used in combination, the RAINS (Regional Acidification INformations and Simulation) model, the SAFE (Simulating Acidification in Forest Ecosystems) model and the MakeDep model. The scenarios used were based on results from international negotiations (the Oslo and Sofia protocols) and on calculations of what could be achieved using the best available technology at a reasonable cost. The parameters chosen for studying the course of acidification were base saturation, BC.Al molar ratio in soil solution and pH. Furthermore, the sites were compared with respect to deposition regimes as well as ion exchange and weathering rates, nutrient uptake and nutrient cycling. The results show, that all sites have undergone acidification. Three of the sites show BC.Al molar ratios below or very close to the threshold value of 1. Currently accepted reductions in S and N emissions will lead to a halt in acidification in all cases and a partial regeneration of the soil buffer capacity in some cases. Introducing maximum feasible reductions would improve soil conditions remarkably at all six sites. The differences in degree and course of acidification can be derived from differences in weathering rate and soil buffer capacity as well as from the deposition regimes. Detailed information on future anthropogenic base cation deposition is shown to be less important for the outcome of the scenarios than expected