Experimental and theoretical investigations of a rectangular grating structure for low-voltage traveling wave tube amplifiers

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Extended frequency compensation of a diamagnetic loop

A method of compensation for a diamagnetic loop that is magnetically coupled to a concentric stainless-steel vacuum vessel is presented. This compensation method accounts for imperfect magnetic coupling between the vessel eddy currents, the diamagnetic loop, and the plasma diamagnetic currents, and it also corrects for a finite loading resistance on the diamagnetic loop. A procedure for adjusting and calibrating the active-filter compensation circuit is presented. It can be applied to internal or external diamagnetic loops.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/49110/2/ppv28i9Bp1449.pd

Cationic Peptide Exposure Enhances Pulsed-Electric-Field-Mediated Membrane Disruption

Background: The use of pulsed electric fields (PEFs) to irreversibly electroporate cells is a promising approach for destroying undesirable cells. This approach may gain enhanced applicability if the intensity of the PEF required to electrically disrupt cell membranes can be reduced via exposure to a molecular deliverable. This will be particularly impactful if that reduced PEF minimally influences cells that are not exposed to the deliverable. We hypothesized that the introduction of charged molecules to the cell surfaces would create regions of enhanced transmembrane electric potential in the vicinity of each charged molecule, thereby lowering the PEF intensity required to disrupt the plasma membranes. This study will therefore examine if exposure to cationic peptides can enhance a PEF’s ability to disrupt plasma membranes. Methodology/Principal Findings We exposed leukemia cells to 40 μs PEFs in media containing varying concentrations of a cationic peptide, polyarginine. We observed the internalization of a membrane integrity indicator, propidium iodide (PI), in real time. Based on an individual cell’s PI fluorescence versus time signature, we were able to determine the relative degree of membrane disruption. When using 1–2 kV/cm, exposure to >50 μg/ml of polyarginine resulted in immediate and high levels of PI uptake, indicating severe membrane disruption, whereas in the absence of peptide, cells predominantly exhibited signatures indicative of no membrane disruption. Additionally, PI entered cells through the anode-facing membrane when exposed to cationic peptide, which was theoretically expected. Conclusions/Significance: Exposure to cationic peptides reduced the PEF intensity required to induce rapid and irreversible membrane disruption. Critically, peptide exposure reduced the PEF intensities required to elicit irreversible membrane disruption at normally sub-electroporation intensities. We believe that these cationic peptides, when coupled with current advancements in cell targeting techniques will be useful tools in applications where targeted destruction of unwanted cell populations is desired

HMO Participation in Medicare+Choice

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75542/1/j.1530-9134.2005.00073.x.pd

Modern microwave methods in solid state inorganic materials chemistry: from fundamentals to manufacturing

No abstract available