Seven schemes to maintain the ∇·B=0 constraint numerically are compared. All these algorithms can be combined with shock-capturing Godunov type base schemes. They fall into three categories: the ...eight-wave formulation maintains the constraint to truncation error, the projection scheme enforces the constraint in some discretization by projecting the magnetic field, while the five different versions of the constrained transport/central difference type schemes conserve ∇·B to machine accuracy in some discretization for every grid cell. It is shown that the three constrained transport algorithms, which have been introduced recently, can be recast into pure finite volume schemes, and the staggered representation of the magnetic field is unnecessary. Another two new and simple central difference based algorithms are introduced. The properties of the projection scheme are discussed in some detail, and I prove that it has the same order of accuracy as the base scheme even for discontinuous solutions. I describe a flexible and efficient implementation of the projection scheme using conjugate gradient type iterative methods. Generalizations to resistive MHD, to axial symmetry, and to non-Cartesian grids are given for all schemes. The theoretical discussion is followed by numerical tests, where the robustness, accuracy, and efficiency of the seven schemes and the base scheme can be directly compared. All simulations are done with the Versatile Advection Code, in which several shock-capturing base schemes are implemented. Although the eight-wave formulation usually works correctly, one of the numerical tests demonstrates that its non-conservative nature can occasionally produce incorrect jumps across strong discontinuities. Based on a large number of tests, the projection scheme, one of the new central difference based schemes, and one of the constrained transport schemes are found to be the most accurate and reliable among the examined methods.
Some filoviruses can be transmitted to humans by zoonotic spillover events from their natural host and filovirus outbreaks have occured with increasing frequency in the last years. The filovirus ...Lloviu virus (LLOV), was identified in 2002 in Schreiber's bats (Miniopterus schreibersii) in Spain and was subsequently detected in bats in Hungary. Here we isolate infectious LLOV from the blood of a live sampled Schreiber's bat in Hungary. The isolate is subsequently sequenced and cultured in the Miniopterus sp. kidney cell line SuBK12-08. It is furthermore able to infect monkey and human cells, suggesting that LLOV might have spillover potential. A multi-year surveillance of LLOV in bats in Hungary detects LLOV RNA in both deceased and live animals as well as in coupled ectoparasites from the families Nycteribiidae and Ixodidae. This correlates with LLOV seropositivity in sampled Schreiber's bats. Our data support the role of bats, specifically Miniopterus schreibersii as hosts for LLOV in Europe. We suggest that bat-associated parasites might play a role in the natural ecology of filoviruses in temperate climate regions compared to filoviruses in the tropics.
In this paper, a case of an 82‐year‐old man who was admitted to our department with sever symptomatic degenerative aortic valve stenosis is presented and discussed. After all screening procedures, a ...successful transfemoral transcatheter aortic valve replacement was performed, but the closure of the femoral access was unsuccessful due to suture‐based device failure. We decided to perform a prolonged balloon dilatation and external compression at the bleeding site, but the bleeding did not stop; therefore, an iCover stent graft was implanted from distal radial artery access using slender technique. Following that, the bleeding was stopped, and the patient had an uneventful outcome.
Abstract
In a previous study, Huang et al. used the Alfvén Wave Solar atmosphere Model, one of the widely used solar wind models in the community, driven by ADAPT-GONG magnetograms to simulate the ...solar wind in the last solar cycle and found that the optimal Poynting flux parameter can be estimated from either the open field area or the average unsigned radial component of the magnetic field in the open field regions. It was also found that the average energy deposition rate (Poynting flux) in the open field regions is approximately constant. In the current study, we expand the previous work by using GONG magnetograms to simulate the solar wind for the same Carrington rotations and determine if the results are similar to the ones obtained with ADAPT-GONG magnetograms. Our results indicate that similar correlations can be obtained from the GONG maps. Moreover, we report that ADAPT-GONG magnetograms can consistently provide better comparisons with 1 au solar wind observations than GONG magnetograms, based on the best simulations selected by the minimum of the average curve distance for the solar wind speed and density.
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•There are structural changes at the blood-brain barrier (BBB) with aging.•Microdialysis and SPECT data suggest reduced function of P-pg at the BBB with aging.•Immunohistochemistry ...revealed a reduced expression of P-gp in the brain with aging.•The brain exposure to quinidine after P-gp inhibition increased more in young rats.
Decreased beta-amyloid clearance in Alzheimer’s disease and increased blood-brain barrier permeability in aged subjects have been reported in several articles. However, morphological and functional characterization of blood-brain barrier and its membrane transporter activity have not been described in physiological aging yet. The aim of our study was to explore the structural changes in the brain microvessels and possible functional alterations of P-glycoprotein at the blood-brain barrier with aging. Our approach included MR imaging for anatomical orientation in middle aged rats, electronmicroscopy and immunohistochemistry to analyse the alterations at cellular level, dual or triple-probe microdialysis and SPECT to test P-glycoprotein functionality in young and middle aged rats. Our results indicate that the thickness of basal lamina increases, the number of tight junctions decreases and the size of astrocyte endfeet extends with advanced age. On the basis of microdialysis and SPECT results the P-gp function is reduced in old rats. With our multiparametric approach a complex regulation can be suggested which includes elements leading to increased permeability of blood-brain barrier by enhanced paracellular and transcellular transport, and factors working against it. To verify the role of P-gp pumps in brain aging further studies are warranted.
Canine distemper virus (CDV) endangers a wide range of wild animal populations, can cross species barriers and therefore representing a significant conservational and animal health risk around the ...globe. During spring to autumn 2021, according to our current estimates a minimum of 50 red foxes (Vulpes vulpes) died of CDV in Hungary, with CDV lesions. Oral, nasal and rectal swab samples were RT-PCR screened for Canine Distemper Virus from red fox carcasses. To investigate in more detail the origins of these CDV strains, 19 complete genomes were sequenced with a pan-genotype CDV-specific amplicon-based sequencing method developed by our laboratory and optimized for the Oxford Nanopore Technologies platform. Phylogenetic analysis of the complete genomic sequences and separately the hemagglutinin gene sequences revealed the role of the Europe lineage of CDV as a causative agent for the current epizootic. Here we highlight the growing importance of fast developing rapid sequencing technologies to aid rapid response activities during epidemics or epizootic events. We also emphasize the urgent need for improved surveillance of CDV, considering the epizootic capability of enzootic strains as reported in the current study. For such future efforts, we provide a novel NGS protocol to facilitate future genomic surveillance studies.
Using a two‐way coupled magnetohydrodynamics with embedded kinetic physics model, we perform a substorm event simulation to study electron velocity distribution functions (VDFs) evolution associated ...with Bursty Bulk Flows (BBFs). The substorm was observed by Magnetospheric Multiscale satellite on 16 May 2017. The simulated BBF macroscopic characteristics and electron VDFs agree well with observations. The VDFs from the BBF tail to its dipolarization front (DF) during its earthward propagation are revealed and they show clear energization and heating. The electron pitch angle distributions (PADs) at the DF are also tracked, which show interesting energy dependent features. Lower energy electrons develop a “two‐hump” PAD while the higher energy ones show persist “pancake” distribution. Our study reveals for the first time the evolution of electron VDFs as a BBF moves earthward using a two‐way coupled global and kinetic model, and provides valuable contextual understanding for the interpretation of satellite observations.
Plain Language Summary
Bursty bulk flows (BBFs) are identified as the fast earthward‐propagating flows from magnetic reconnection in the Earth's magnetotail. BBFs are related to particle energization and heating processes as reported by satellite observations. For the first time, we use a novel numerical model that simulates kinetic physics directly in a global model. The electron velocity distribution functions extracted from multiple locations associated with BBF show good agreements with the satellite in situ observations. The energization and heating of the electrons associated with BBF and their energy‐dependent pitch angle distributions are revealed.
Key Points
For the first time, we simulate the bursty bulk flow (BBF) events with kinetic physics embedded in a global magnetosphere model
The electron velocity distribution functions exhibit different anisotropy features at different locations of the BBF
Energy dependent electron pitch angle distribution evolutions are identified in the simulation
The introduction of the first antibiotic (penicillin) by Sir Alexander Fleming in 1928 was a huge milestone in the treatment of infectious diseases ....
As a consequence of the fast resistance spreading, a limited number of drugs are available to treat fungal infections. Therefore, there is an urgent need to develop new antifungal treatment ...strategies. The features of a disulfide bond‐stabilized antifungal protein, NFAP2 secreted by the mold Neosartorya (Aspergillus) fischeri render it to be a promising template for future protein‐based antifungal drug design, which requires knowledge about the native disulfide linkage pattern as it is one of the prerequisites for biological activity. However, in the lack of tryptic and chymotryptic proteolytic sites in the ACNCPNNCK sequence, the determination of the disulfide linkage pattern of NFAP2 is not easy with traditional mass spectrometry‐based methods. According to in silico predictions working with a preliminary nuclear magnetic resonance (NMR) solution structure, two disulfide isomers of NFAP2 (abbacc and abbcac) were possible. Both were chemically synthesized; and comparative reversed‐phase high‐performance liquid chromatography, electronic circular dichroism and NMR spectroscopy analyses, and antifungal susceptibility and efficacy tests indicated that the abbcac is the native pattern. This knowledge allowed rational modification of NAFP2 to improve the antifungal efficacy and spectrum through the modulation of the evolutionarily conserved γ‐core region, which is responsible for the activity of several antimicrobial peptides. Disruption of the steric structure of NFAP2 upon γ‐core modification led to the conclusions that this motif may affect the formation of the biologically active three‐dimensional structure, and that the γ‐core modulation is not an efficient tool to improve the antifungal efficacy or to change the antifungal spectrum of NFAP2.
We investigate the use of artificially increased ion and electron kinetic scales in global plasma simulations. We argue that as long as the global and ion inertial scales remain well separated, (1) ...the overall global solution is not strongly sensitive to the value of the ion inertial scale, while (2) the ion inertial scale dynamics will also be similar to the original system, but it occurs at a larger spatial scale, and (3) structures at intermediate scales, such as magnetic islands, grow in a self‐similar manner. To investigate the validity and limitations of our scaling hypotheses, we carry out many simulations of a two‐dimensional magnetosphere with the magnetohydrodynamics with embedded particle‐in‐cell (MHD‐EPIC) model. The PIC model covers the dayside reconnection site. The simulation results confirm that the hypotheses are true as long as the increased ion inertial length remains less than about 5% of the magnetopause standoff distance. Since the theoretical arguments are general, we expect these results to carry over to three dimensions. The computational cost is reduced by the third and fourth powers of the scaling factor in two‐ and three‐dimensional simulations, respectively, which can be many orders of magnitude. The present results suggest that global simulations that resolve kinetic scales for reconnection are feasible. This is a crucial step for applications to the magnetospheres of Earth, Saturn, and Jupiter and to the solar corona.
Key Points
The effects of artificially increased kinetic scales are studied with MHD‐EPIC simulations
Changing the kinetic scales does not change the global solution significantly
Increasing the kinetic scales makes global simulations with embedded kinetic regions feasible
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