Despite of the increasing number of investigations on the effects of acute exercise on circulating stem and progenitor cell (SC) numbers, and in particular on respective subgroups, i.e. endothelial ...(ESC), hematopoietic (HSC), and mesenchymal (MSC) stem and progenitor cells, a consensus regarding mechanisms and extent of these effects is still missing. The aim of this meta-analysis was to systematically evaluate the overall-effects of acute exercise on the different SC-subgroups and investigate possible subject- and intervention-dependent factors affecting the extent of SC-mobilization in healthy humans. Trials assessing SC numbers before and at least one timepoint after acute exercise, were identified in a systematic computerized search. Compared to baseline, numbers were significantly increased for early and non-specified SCs (enSCs) until up to 0.5 h after exercise (0–5 min: +0.64 Standardized difference in means,
p
< 0.001; 6–20 min: +0.42,
p
< 0.001; 0.5 h: +0.29,
p
= 0.049), for ESCs until 12–48 h after exercise (0–5 min: +0.66,
p
< 0.001; 6–20 min: +0.43
p
< 0.001; 0.5 h: +0.43,
p
= 0.002; 1 h: +0.58,
p
= 0.001; 2 h: +0.50,
p
= 0.002; 3–8 h: +0.70,
p
< 0.001; 12–48 h: +0.38,
p
= 0.003) and for HSCs at 0–5 min (+ 0.47,
p
< 0.001) and at 3 h after exercise (+ 0.68,
p
< 0.001). Sex, intensity and duration of the intervention had generally no influence. The extent and kinetics of the exercise-induced mobilization of SCs differ between SC-subpopulations. However, also definitions of SC-subpopulations are non-uniform. Therefore, finding a consensus with a clear definition of cell surface markers defining ESCs, HSCs and MSCs is a first prerequisite for understanding this important topic.
Graphical Abstract
•Na pool fire models and aerosol chemical ageing developed and implemented in ASTEC-Na.•ASTEC-Na estimates compared to data from AB1, AB2, F2 and EMIS10 tests.•Further work mandatory for a ...mechanistic modeling and a sound validation.•A robust database with old and new tests is a need.
The ASTEC-Na code is being developed to simulate any sort of postulated accidents in Na-cooled fast reactors, particularly severe accidents. A significant progress has been made in the development of source term models, their implementation in the code and the specific validation of the specific code module, hereafter named CPA∗, under the auspices of the JASMIN project.
In this paper the fundamentals of models for Na pool fire thermal-hydraulics and particle generation and chemical ageing of airborne particulates are described. Based mostly on data gathered from the open literature, CPA∗ performance under conditions anticipated during Na pool fires has been assessed against AB1, AB2, F2 and EMIS10 experiments. Thermal-hydraulic estimates have shown acceptable generic trends with noticeable quantitative deviations, despite the highly parametrized models used. A similar statement concerning aerosol behavior following measurements tendency is also applicable. As for chemical ageing, the comparisons set indicate that further work is still necessary. Therefore, even though some significant progress has been achieved, it is unquestionable that further work needs to be done in the three areas addressed. Finally, it should be highlighted that one of the main outcomes of this work is the need of obtaining qualified data for models and codes validation, so that a thorough and sound model assessment and code validation can be conducted.
•In-containment Na aerosol data retrieved and gathered for code validation.•Comparison of ASTEC-Na models for Na pool fires and aerosol ageing to data.•Generic trends captured through a heavy models ...parametrization.•Need for qualified data from representative experiments during Na pool fires.
Modeling the containment response to a sodium pool fire is to be one of the key aspects of any comprehensive safety evaluation of the new generation of sodium cooled fast reactors. Through a peer review of earlier experimental investigations some useful data can be collected and then used for assessing the current analytical capabilities to model severe accidents or some of their specific aspects. This paper provides major insights into the in-containment aerosol behavior predictability of ASTEC-Na (CPA∗ module) during Na-pool fires. By comparing against tests from the ABCOVE (AB1 and AB2) and FAUNA (F2) programs, it has been shown that experimental trends can be roughly reproduced with a single-cell approach whenever natural convection is effective in making the vessel atmosphere uniform both thermally and in composition. Nonetheless, the present heavy parametrization of ASTEC-Na models should be avoided or strongly supported by further experimentation that allows setting sound default values, concerning both combustion energy distribution and aerosol formation and distribution. Anyway, the peer data review has highlighted that a meaningful comparison to predictions is not always feasible due to large data uncertainties, particularly at the beginning of Na burning. As for the particle ageing, the comparisons set seems to indicate that transformation from oxides to hydroxides is predicted to be too slow; nevertheless, a more extensive benchmarking should be conducted to confirm it.
Abstract Purpose Levetiracetam is an antiepileptic medication that has been reported to be both well-tolerated and effective in treating generalized tonic-clonic, myoclonic, and partial-onset ...seizures. The adverse effects most commonly reported in tolerability trials include somnolence, fatigue/asthenia, headaches, dizziness, and nausea. However, there have been a few reports suggesting possible detrimental effects of levetiracetam on renal function. Methods Here we describe the case of a previously healthy 23-year-old female patient who developed acute kidney injury 1 day after the initiation of levetiracetam therapy for new-onset seizures. Findings Based on the time course of the patient’s rise in serum creatinine and the exclusion of other causes, this case suggests that levetiracetam use contributed to the acute kidney injury. Implications Levetiracetam is a widely used drug that has been reported to be generally tolerable and effective; however, it has the potential to negatively affect renal function. This potential consequence of therapy should be considered when deciding whether or not to prescribe this medication, and renal function should be monitored during treatment.
•New release AC2 2019 contains ATHLET/ATHLET-CD 3.2 and COCOSYS 3.0.•Validation of AC2 codes and validation matrices are discussed.•Improvements for ATHLET 3D model, AIDA lower plenum module and SAFT ...FP transport.•For MCCI simulation in COCOSYS, set concrete decomposition temperatures to 1800 K.•Stable coupling at multiple locations of ATHLET to CFD-codes for single-phase flows.
The system code package AC2 by GRS for safety analyses of nuclear reactors from normal operation to severe accidents has been updated with a new release. We briefly describe the main modules of AC2 2019: ATHLET 3.2, ATHLET-CD 3.2 and COCOSYS 3.0 and selected improvements in these codes.
We illustrate the improved capabilities of AC2 with selected examples. The post-test-calculation of the flooding pool of the INKA test facility demonstrated the improved ATHLET 3D model with explicit mixture level model. For ATHLET-CD, we apply the AIDA module with improvements in wall ablation and heat transfer models to a generic AP1000 lower plenum filled with molten corium. And we apply the new SAFT fission product transport module simulating three release paths through steam generator U-tubes. For COCOSYS, we present uncertainty analysis results for two MCCI experiments which justify using an elevated concrete decomposition temperature of 1800 K. Finally, we illustrate the potential of coupling ATHLET to CFD codes for safety analysis with results of a post-test calculation of the ROCOM PKLIIIT1.1 test on 3D mixing phenomena in an RPV.
•Model for ex-vessel core catchers in Gen. 3+ NPPs for the SA code AC2/COCOSYS.•MCCI phase: Use of MCCI model approach during the melting of sacrificial material.•Retention phase: Conduction through ...the core catcher walls and outer water cooling.•Validation of the model approach vs. the WCB-1 test of the OECD MCCI-2 project.•A test calculation for the core catcher of a WWER-1200 plant, based on public data.
In Generation 3+ NPPs such as EPR or WWER-1200 the ex-vessel core catcher presents a key component of the severe accident mitigation concept. A simplified core catcher model in the containment code COCOSYS (part of AC2 code package) is developed to consider core melt retention and cooling phenomena in core catchers for containment simulations. The model enables the characterization of the corium in the core catcher including processes in the corium conditioning phase (melting of sacrificial material in the core catcher, oxidation of metallic components, possible layer flip) and the long-term cooling phase (evolution of long-term corium pool bulk temperature and changes in physical state). The core catcher model is based on the existing molten corium / concrete interaction (MCCI) model in COCOSYS with additions for melt retention within water-cooled structures and input data can be adapted to simulate various core catcher design features of e. g. NPPs with EPR or WWER.
The current state of the model, including basic assumptions, calculation methods, simplifications, and two application examples are outlined. The recalculation of the water-cooled basemat test OECD WCB-1 shows that the experimental data regarding e. g. the ablation of the sacrificial concrete on top of the water-cooled basemat, corium pool temperature and heat fluxes at water-cooled interfaces can be adequately reproduced by the COCOSYS simulation, when using empirical data for the heat transfer, including the MCCI phase. These empirical heat transfer data agree well with findings obtained from recent analytical work on MCCI tests. However, the model does not predict high local bottom plate temperatures as observed in the WCB-1 test due to a restriction of the model to quasi-steady state processes. The second calculation example demonstrates the current modelling features when applied to an axisymmetric geometry of a reactor-scale core catcher. With view to reactor-scale, the model is ready for a further verification, like e.g. comparison with other analytical core catcher approaches.
Modelling of sodium-evaporation and formation of sodium-oxide aerosols from a sodium-pool fire is of fundamental importance for the assessing of the radiological consequences in Sodium-cooled Fast ...Reactors severe accidents. This paper summarizes the derivation of a simple model to estimate the amount and size of particles being generated from Na-pool fires and its performance assessment, once implemented in an integral severe accident tool (ASTEC-Na), against available large-scale separate effect tests. The model has been transposed in analytical correlations which implementation in lumped-parameter severe accident codes is straightforward. According to the comparisons to data set, the correlations do not adversely impact the code estimates with respect to other more empirical alternative approaches and, in addition, the correlations remove any need of user-defined ad-hoc parameters in the input deck concerning Na-based particles behaviour, as other alternates do. Regarding code behaviour, the model predictions yield the same order of magnitude both in terms of suspended aerosol concentration and diameter as data and capture the reliable measured data trends.
•Development of particle generation model for sodium-oxides aerosol formation.•Encapsulation of a zero-D model to correlations compatible to lumped parameter codes.•In-containment particulate source term prediction.•Assessment of the model performance against open large scale experiments.•Implementation of derived correlations to a lumped parameter code (ASTEC-Na).
New Findings
What is the central question of this study?
Although peripheral blood haematopoietic stem and progenitor cells are potentially important in regeneration after acute myocardial ...infarction, their self‐renewal ability in the post‐acute phase has not yet been addressed.
What is the main finding and its importance?
In rat peripheral blood, we show that myocardial infarction does not negatively affect circulating haematopoietic stem and progenitor cell self‐renewal ability 2 weeks after acute infarction, which suggests a constant regenerative potential in the myocardial infarction post‐acute phase.
Given the importance of peripheral blood haematopoietic stem and progenitor cells (HPCs) in post‐acute regeneration after acute myocardial infarction (MI), the aim of the present study was to investigate the number and secondary replating capacity/self‐renewal ability of HPCs in peripheral blood before and 2 weeks after MI. In female Lewis inbred rats (n = 9), MI was induced by ligation of the left coronary artery, and another nine underwent sham surgery, without ligation, for control purposes. Myocardial infarction was confirmed by troponin I concentrations 24 h after surgery. Peripheral blood was withdrawn and fractional shortening and ejection fraction of the left ventricle were assessed before (day 0) and 14 days after MI or sham surgery (day 14). After mononuclear cell isolation, primary and secondary functional colony‐forming unit granulocyte–macrophage (CFU‐GM) assays were performed in order to detect the kinetics of functional HPC colony counts and cell self‐renewal ability in vitro. The CFU‐GM counts and cell self‐renewal ability remained unchanged (P > 0.05) in both groups at day 14, without interaction between groups. In the intervention group, higher day 0 CFU‐GM counts showed a relationship to lower fractional shortening on day 14 (ρ = −0.82; P < 0.01). Myocardial infarction did not negatively affect circulating HPC self‐renewal ability, which suggests a constant regenerative potential in the post‐acute phase. A relationship of cardiac contractile function 14 days after MI with circulating CFU‐GM counts on day 0 might imply functional colony count as a predictive factor for outcome after infarction.
PDF
