Greatly attenuated experimental autoimmune encephalomyelitis in aquaporin-4 knockout mice

Background  

The involvement of astrocyte water channel aquaporin-4 (AQP4) in autoimmune diseases of the central nervous system has been suggested following the identification of AQP4 autoantibodies in neuromyelitis optica, an inflammatory demyelinating disease.     

Quantum superarrivals and information transfer through a time-varying boundary

The time-dependent Schrödinger equation is solved numerically for the case of a Gaussian wave packet incident on a time-varying potential barrier. The time evolving reflection and transmission probabilities of the wave packet are computed for several different time-dependent boundary conditions obtained by reducing or increasing the height of the potential barrier. We show that in the case when the barrier height is reduced to zero, a time interval is found during which the reflection probability is larger (superarrivals) compared to the unperturbed case. We further show that the transmission probability exhibits superarrivals when the barrier is raised from zero to a finite value of its height. Superarrivals could be understood by ascribing the features of a real physical field to the Schrödinger wave function which acts as a carrier through which a disturbance, resulting from the boundary condition being perturbed, prpagates from the barrier to the detectors measuring reflected and transmitted probabilities. The speed of propagation of this effect depends upon the rate of reducing or raising the barrier height, thus suggesting an application for secure information transfer using superarrivals.     

Spatial and temporal evolution of high-energy density plasmas inthe composite pinch on GIT-4 generator

A series of collaborative experiments on complex plasma loads has been carried out on the large inductive energy storage generator GIT-4. The aim of the experiments is to explore the different configurations for the formation of ultrahigh-energy density plasmas in high-voltage pulsed-power systems by direct electromagnetic energy coupling. In this paper, we present some of the underlying philosophy on these experiments and the results obtained. Particular emphasis is placed on the pulsed-power aspects and the effect of source-load coupling for the different studied Z-pinch loads. Resulting radiative properties of the classical exploding wire and liner are experimentally compared with those of the composite pinch scheme in which an intermediate low-density shell is used for staged energy transfer onto a micron-sized wire     

Experimental investigation on a long-conduction time-plasma openingswitch and its application on a 0.1 TW generator for prepulsesuppression

The authors discuss their work on plasma opening switches (POSs). After characterization of the plasma created by plasma guns, physical processes occurring during long-conduction-time POS operation are investigated using diagnostics such as Rogowski coils, Faraday cups, and time-integrated and streak photographs. The importance of different parameters of the authors' system, such as the generator charging voltage, the geometry of the switch, and the plasma density, are studied. The authors' results are correlated with two theoretical models. The experiment shows that the use of an 80% transparent inner electrode can significantly increase the opening speed. The POS is applied in a short-conduction-time experiment. Results obtained in upgrading of a 0.1-TW generator (2 Ω, ~250 kA, ~50 ns) are presented. Prepulse suppression is achieved with a short-circuit load and with an aluminum vapor Z-pinch as a load. Incorporation of the POS improves the compression of the Z-pinch and increases the radiation yield     

Radiative properties of mixed nested cylindrical wire arrays on Zebra at UNR

The dynamics of mixed nested cylindrical wire arrays were studied at the UNR Zebra generator with our existing theoretical and experimental tools to better understand the contributions of each array to the emitted radiation. In particular, experimental results of mixed brass (70% Cu, 30% Zn) and Al (5056, 5% Mg) nested cylindrical wire arrays are analyzed and compared. The loads used brass in the inner array and Al in the outer array, or alternately, Al in the inner array and brass in the outer array, with a mass ratio of 1:1 (outer to inner). Consequently, radiative properties of K-shell Al and Mg ions and L-shell Cu and Zn ions are compared as functions of the placements of the brass and Al wires on the inner and outer arrays. Results show that the placement of brass and Al, whether on the inner or outer array, dramatically affects the intensity of the X-ray emission. Specifically, the ratio of Cu L-shell to Al K-shell emissions changed from 4 when Al is in the outer array to 40 when brass is in the outer array, and the total radiated yield was highest when the brass was on the outer array (18 kJ, versus 15 kJ when brass is on the inner array). Each load was fielded twice to vary the timing of the time-gated imaging and spectral diagnostics. This provides a more complete understanding of the evolution of the plasma parameters over the X-ray pulse and highlights the importance of the time-gated diagnostics.