PLASMA-INDUCED RADIO FREQUENCY INTERFERENCES FROM SPACE VEHICLE

1970-03-30Experiments on plasma-induced interferences from DC-DC converter to receiving antenna simulated for the REXS satellite was made in the presence of plasma in the space chamber of low density and low temperature. When the satellite is sunlit, interferences from DC-DC converter inside the spaceraft, to the receiving antenna via solar panel is found greatly to be enhanced due to the presence of plasma. Matal plate experiment simulated for solar panel showed that the presence of plasma increased the capacitive coupling when the matal plate as transmitter was positively or negatively DC biased, while the receiving antenna was not biased, and especially when the metal plate is positively biased at the space potential, conductive coupling was found to be superposed on this capacitive coupling. However, wavy coupling was not recognized.departmental bulletin pape

Monitoring of intracellular 1-beta-D-arabinofuranosylcytosine 5'-triphosphate in 1-beta-D-arabinofuranosylcytosine therapy at low and conventional doses.

1-beta-D-Arabinofuranosylcytosine (ara-C) is used empirically at a low, conventional, or high dose. Ara-C therapy may be optimal if it is directed by the clinical pharmacokinetics of the intracellular active metabolite of ara-C, 1-beta-D-arabinofuranosylcytosine 5'-triphosphate (ara-CTP). However, ara-CTP has seldom been monitored during low- and conventional-dose ara-C therapies because detection methods were insufficiently sensitive. Here, with the use of our newly established method (Cancer Res., 56, 1800 -- 1804 (1996)), ara-CTP was monitored in leukemic cells from acute myelogenous leukemia patients receiving low- or conventional-dose ara-C [subcutaneous ara-C administration (10 mg / m(2) ) (3 patients), continuous ara-C infusion (20 or 70 mg / m(2) / 24 h) (7 patients), 2-h ara-C infusion (70 mg / m(2) ) (4 patients), and 2-h infusion of N(4)-behenoyl-1-beta-D-arabinofuranosylcytosine, a deaminase-resistant ara-C derivative (70 mg / m(2) ) (6 patients)]. Ara-CTP could be determined at levels under 1 microM. There was a close correlation between the elimination half-life values of the plasma ara-C and the intracellular ara-CTP. The presence of ara-C in the plasma was important to maintain ara-CTP. The continuous ara-C and the 2-h N(4)-behenoyl-1-beta-D-arabinofuranosylcytosine infusions maintained ara-CTP and the plasma ara-C longer than the subcutaneous ara-C or the 2-h ara-C infusion. They also afforded relatively higher ara-CTP concentrations, and consequently produced ara-CTP more efficiently than the 2-h ara-C infusion. Different administration methods produced different quantities of ara-CTP even at the same dose.othe

Reconciling Privacy and Security in Pervasive Computing - The Case for Pseudonymous Group Membership

In this paper, we outline an approach to the identification of entities for access control that is based on the membership of groups, rather than individuals. By using group membership as a level of indirection between the individual and the system, we can increase privacy and provide incentives for better behaviour. Privacy comes from the use of pseudonyms generated within the group and which can be authenticated as belonging to the group. The incentives for better behaviour come from the continuous nature of groups - members may come and go, but the group lives on, and groups are organised so as to ensure group-longevity, and prevent actions which may harm the groups reputation. We present a novel pseudonym generation mechanism suitable for use in groups without a centralised administration. Finally, we argue that the use of group membership as the basis for formulating policies on interaction is more efficient for disconnected operation, facilitating proxies and the efficient storage of revoked membership and distrusted organisations within bloom filters for small memory footprints

K_m values of the unwinding of four DNA substrates by WRN and BLM helicases.

<p>The listed K_m values were determined as described under ‘<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0030189#s2" target="_blank">Materials and Methods</a>’ and in the legend to <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0030189#pone-0030189-g002" target="_blank">Fig. 2</a>.</p>a<p>N – Number of independent determinations of each K_m value.</p>b<p>ND – Not determined; the extent of unwinding of bubble DNA by BLM (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0030189#pone-0030189-t001" target="_blank">Table 1</a>) was too low to permit determination of a reliable K_m value.</p

Dissociation constants, K_d, of complexes of different DNA substrates with the WRN and BLM helicases.

<p>The listed K_d values were determined as described under ‘<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0030189#s2" target="_blank">Materials and Methods</a>’ and in the legend to <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0030189#pone-0030189-g005" target="_blank">Fig. 5</a>.</p>a<p>N – Number of independent determinations of each K_d value.</p>b<p>ND – Not determined; the extent of complex formation between BLM and these DNA structures (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0030189#pone-0030189-g003" target="_blank">Figs. 3</a> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0030189#pone-0030189-g004" target="_blank">4</a>) was too low to permit determination of reliable K_d values.</p

Schemes of DNA structures used in this work.

<p>Annealing of oligomers to form partial DNA duplexes, bubble and splayed arm DNA and formation of the G'4 monomolecular and G'2 bimolecular quadruplex structures of TeR₄₃ and TeR₆₃ oligomers and of G4 four-molecular quadruplex form of the IgG DNA switch region were performed as described under ‘<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0030189#s2" target="_blank">Materials and Methods</a>’.</p

Determination of the dissociation constant, K_d, of complexes of WRN protein with a 20/46 partial DNA duplex.

<p>Decreasing amounts of 5′-³²P labeled 20/46 partial DNA duplex were incubated under binding conditions with 12 fmol of WRN protein per assay mixture and formed protein-DNA complexes were resolved from free DNA by non-denaturing electrophoresis through 4% polyacrylamide gels in 0.5 X Tris-glycine buffer. Upper panel; Phosphor image of gel-resolved protein-DNA complexes and free DNA. Lower panel; Scatchard plots of the quantified results. A K_d value was inferred from the negative reciprocal of the slope of the shown plot.</p

Determination of the kinetics of the unwinding of splayed arm DNA by WRN and BLM helicases.

<p>Assay conditions for helicase-catalyzed unwinding of 5′-³²P labeled splayed arm DNA, electrophoretic resolution of unwound DNA and its quantification by Phosphor Imager analysis were carried out as detailed in the ‘<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0030189#s2" target="_blank">Materials and Methods</a>’ section. Upper panels; Phosphor images of splayed arm DNA resolved by electrophoresis through non-denaturing 12% polyacrylamide gels in 0.5 X Tris-glycine buffer. Controls (leftward lanes) included DNA incubated without helicase under unwinding reaction conditions and DNA boiled without helicase for 10 min to identify the position of its labeled single-strand component. Lower panels; Lineweaver-Burk plots of the quantified results.</p

Unwinding efficacies of DNA substrates by WRN and BLM helicases.

<p>Increasing amounts of WRN or BLM helicases were incubated under standard DNA unwinding conditions, (‘<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0030189#s2" target="_blank">Materials and Methods</a>’), with 100 fmol DNA substrate per reaction mixture.</p>a<p>Presented values expressed as fmols DNA unwound by 6.2 fmol helicase protein, are averages of at least three independent determinations derived from the linear sections of unwinding titration curves.</p>b<p>Activity relative to the unwinding of the 20/46 partial DNA duplex.</p

Binding of different DNA structures by increasing amounts of WRN or BLM proteins.

<p>Indicated increasing amounts of either WRN or BLM were incubated under DNA binding conditions (‘<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0030189#s2" target="_blank">Materials and Methods</a>’) with 120 fmol of specified 5′-³²P labeled DNA structure per assay mixture. Protein-DNA complexes were resolved by electrophoresis through non-denaturing 4% polyacrylamide gels in 0.5 X Tris-glycine buffer with or without 10 mM KCl for quadruplex or duplex DNA, respectively. Presented are results of Phosphor Imager-quantified amounts of protein-bound DNA as a function of the amount of added helicase.</p