Afterlive: A performant code for Vlasov-Hybrid simulations

A parallelized implementation of the Vlasov-Hybrid method [Nunn, 1993] is presented. This method is a hybrid between a gridded Eulerian description and Lagrangian meta-particles. Unlike the Particle-in-Cell method [Dawson, 1983] which simply adds up the contribution of meta-particles, this method does a reconstruction of the distribution function $f$ in every time step for each species. This interpolation method combines meta-particles with different weights in such a way that particles with large weight do not drown out particles that represent small contributions to the phase space density. These core properties allow the use of a much larger range of macro factors and can thus represent a much larger dynamic range in phase space density. The reconstructed phase space density $f$ is used to calculate momenta of the distribution function such as the charge density $\rho$. The charge density $\rho$ is also used as input into a spectral solver that calculates the self-consistent electrostatic field which is used to update the particles for the next time-step. Afterlive (A Fourier-based Tool in the Electrostatic limit for the Rapid Low-noise Integration of the Vlasov Equation) is fully parallelized using MPI and writes output using parallel HDF5. The input to the simulation is read from a JSON description that sets the initial particle distributions as well as domain size and discretization constraints. The implementation presented here is intentionally limited to one spatial dimension and resolves one or three dimensions in velocity space. Additional spatial dimensions can be added in a straight forward way, but make runs computationally even more costly.Comment: Accepted for publication in Computer Physics Communication

PICPANTHER: A simple, concise implementation of the relativistic moment implicit Particle-in-Cell method

A three-dimensional, parallelized implementation of the electromagnetic relativistic moment implicit particle-in-cell method in Cartesian geometry (Noguchi et. al., 2007) is presented. Particular care was taken to keep the C++11 codebase simple, concise, and approachable. GMRES is used as a field solver and during the Newton-Krylov iteration of the particle pusher. Drifting Maxwellian problem setups are available while more complex simulations can be implemented easily. Several test runs are described and the code's numerical and computational performance is examined. Weak scaling on the SuperMUC system is discussed and found suitable for large-scale production runs.Comment: 29 pages, 8 figure

Glucocorticoid Receptor Gene Variants and Neonatal Outcome in Very-Low-Birth-Weight Preterm Infants

Background: Induction of lung maturation by prenatal steroid treatment has become the standard of care for pregnant women at risk for preterm birth. In addition to the beneficial effects on lung maturation, prenatal steroids have been shown to reduce the incidence of neonatal death, necrotizing enterocolitis, sepsis, and intraventricular hemorrhage. However, little is known about the role of interindividual differences in corticoid sensitivity arising from polymorphisms in the glucocorticoid receptor (GR) gene. Objectives: To assess the impact of GR polymorphisms N363S (rs56149945), R23K (rs6190), and BclI (rs41423247) on neonatal outcome. Methods: The GR polymorphisms N363S, R23K, and BclI were examined in 10,490 very-low-birth-weight (VLBW) preterm infants from 49 German tertiary level neonatal units (German Neonatal Network, GNN) with respect to neonatal outcome. Results: Infants carrying the BclI genotype were at higher risk to develop bronchopulmonary dysplasia (BPD) (OR 1.12 per BclI allele, 95% CI: 1.02-1.23, p = 0.013) in a logistic regression model adjusted for gestational age, mechanical ventilation, and small for gestational age status. A similar relative risk was seen in the children (89.4%) who received antenatal betamethasone treatment (OR 1.16, 95% CI: 1.05-1.27, p = 0.003), whereas no such effect was detectable in infants without antenatal steroids. N363S and R23K did not show any stable association with neonatal outcome parameters. Conclusion: Except for a slightly higher risk of BPD in carriers of the GRBclI variant, the GR gene polymorphisms BclI, N363S, and R23K did not affect neonatal outcome parameters in this large multicenter cohort of VLBW preterm infants

High-Dimensional Single-Cell Mapping of Central Nervous System Immune Cells Reveals Distinct Myeloid Subsets in Health, Aging, and Disease

Individual reports suggest that the central nervous system (CNS) contains multiple immune cell types with diverse roles in tissue homeostasis, immune defense, and neurological diseases. It has been challenging to map leukocytes across the entire brain, and in particular in pathology, where phenotypic changes and influx of blood-derived cells prevent a clear distinction between reactive leukocyte populations. Here, we applied high-dimensional single-cell mass and fluorescence cytometry, in parallel with genetic fate mapping systems, to identify, locate, and characterize multiple distinct immune populations within the mammalian CNS. Using this approach, we revealed that microglia, several subsets of border-associated macrophages and dendritic cells coexist in the CNS at steady state and exhibit disease-specific transformations in the immune microenvironment during aging and in models of Alzheimer's disease and multiple sclerosis. Together, these data and the described framework provide a resource for the study of disease mechanisms, potential biomarkers, and therapeutic targets in CNS disease

Comparison of postoperative isokinetic quadriceps and gluteal muscular strength after primary THA: is there an early benefit through enhanced recovery programs?

Purpose Although total hip arthroplasty (THA) is expected to result in a postoperative loss of muscular strength, no study investigated the benefit of an enhanced-recovery-after-surgery (ERAS) concept on the hip muscles in detail. We evaluated if (1) an ERAS-concept for primary THA results in reduced loss of muscular strength five days and four weeks postoperative. We (2) compared the two groups regarding Patient-Related-Outcome-Measures (PROMs), WOMAC-index (Western-Ontario-and-McMaster-Universities-Osteoarthritis-Index), HHS (Harris-Hip-Score) and EQ-5d-3L-score. Methods In a prospective, single-blinded, randomized controlled trial, we compared isokinetic muscular strength of 24 patients receiving primary THA with an enhanced recovery concept with early mobilization (n = 12, ERAS-group) and such receiving conventional THA (n = 12, non-ERAS). Isokinetic muscular strength was measured with a Biodex-Dynamometer before, as well as five days and four weeks after surgery (peak-torque, total-work, power). Furthermore, WOMAC, HHS, PROMs and EQ-5d-3L were imposed. Results The ERAS group revealed significant higher isokinetic strength (peak-torque, total-work, power) at both time points. Both groups showed a significant pain decrease at both time points meeting very high rates of patient satisfaction resembled by good results in PROMs, WOMAC, HHS, EQ-5d. There was no significant difference in any of the scores between both groups. Conclusion We proved a significant reduced loss of muscular strength five days and four weeks after primary THA in combination with an ERAS concept. However, the reduced loss of muscular strength is not reflected by patient’s functional outcome and quality of life, showing no significant differences in WOMAC, HHS, EQ-5d-3L, PROMs and NRS. Therefore, this study supports the implementation of an ERAS concept for primary THA in terms of isokinetic strength. Further studies are needed to evaluate the development of muscular strength over a long period

Low-grade inflammation during the glucocorticoid withdrawal phase in patients with Cushing's syndrome

IMPORTANCE Endogenous Cushing's syndrome (CS) leads to profound immunosuppression. Successful surgery induces biochemical remission and reversal of immunosuppression, which is characterized by clinical signs of glucocorticoid withdrawal and associated with increased susceptibility to infections and thromboembolic complications. OBJECTIVE We hypothesized that the glucocorticoid withdrawal phase is characterized by low-grade inflammation that may be related to patient-relevant outcomes. SETTING In this retrospective observational study, we analyzed longitudinal data from 80 patients with CS prospectively enrolled in the German Cushing's registry between 2012 and 2021. All enrolled patients underwent successful surgery. In a second step, a case-control study was performed in 25 of the patients with age-, gender-, and body mass index-matched control patients in whom hypercortisolism was excluded. Analyses included the inflammatory markers C-reactive protein and interleukin-6, as well as body composition, muscle function testing, and quality-of-life questionnaires. The patients were studied during active CS and in the postoperative remission phase 1, 3, 6, 12, and 24 months after surgery. RESULTS Compared with the preoperative phase and matched controls, patients with CS had increased systemic inflammatory markers in the early remission phase. One month following surgery, median (interquartile range) C-reactive protein was 0.48 mg dL-1 (0.14-0.90) vs 0.10 mg dL-1 (0.06-0.39) during active CS (P ≤ .001). Similarly, interleukin-6 1 month after surgery was 7.2 pg mL-1 (3.3-11.7) vs 1.7 pg mL-1 (1.5-2.5) during active CS (P ≤ .001). Obesity and hemoglobin A1c (HbA1c) were associated with increased inflammation levels. This proinflammatory state lasted until 1 year following surgery. Moreover, inflammatory markers during early remission showed an inverse correlation with long-term muscle function. CONCLUSIONS The glucocorticoid withdrawal phase is associated with a low-grade inflammatory state, which is particularly pronounced in obese and hyperglycemic patients and related to lower muscle function