arXiv subjects

N. Sheth

Publications and source records attributed to N. Sheth.

2 recordsLinked to original sources

arXiv2025

Global properties and stability of transonic plasma acceleration in the magnetic nozzle

It is shown that transonic plasma acceleration in the converging-diverging magnetic field (magnetic nozzle) follows the unique global solution which is fully defined by the magnetic field. Such solution, which was analytically obtained earlier in the paraxial approximation, is compared here with results of the axisymmetric two-dimensional (rz) magnetohydrodynamics(MHD) simulations. It is shown that analytical solution describes well the region near the axis but also can be applied to arbitrary magnetic surfaces. The simulations with different length of the nozzle and different boundary values for plasma velocity show that the plasma flow switches to the unique transonic acceleration profile via the shock-like transition in the velocity and pressure profiles. The simulations with arbitrary (not vacuum) initial magnetic field demonstrate the global adjustment of the magnetic field such that the transonic acceleration velocity profile follows the analytic predictions with the modified magnetic field.

physics.plasm-ph↗

arXiv2015

Dynamical System Modeling to Simulate Donor T Cell Response to Whole Exome Sequencing-Derived Recipient Peptides Demonstrates Different Alloreactivity Potential In HLA-Matched and Mismatched Donor-Recipient Pairs

Stem cell transplants may be considered as dynamical systems to allow sequence differences across the exomes of the transplant donors and recipients to be used to simulate an alloreactive T cell response. Whole exome sequencing was performed on HLA matched stem cell transplant donor-recipient pairs, and the nucleotide sequence differences translated to peptides. The binding affinity of the peptides to the relevant HLA in each pair was determined. The resulting array of peptide-HLA binding affinity values in each patient was used to simulate an alloreactive donor derived T cell repertoire. This simulated T cell repertoire reproduces a number of features of clinically observed T cell repertoire. The simulated, alloreactive T cell repertoire was markedly different in HLA matched stem cell transplant donors and recipients and demonstrates a possible correlation with survival.

q-bio.CB↗