989 resultados para Pai-1


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The interaction of benzo-15-crown-5, dibenzo-18-crown-6 and dibenzo-24-crown-8 with 2-dicyanoethylene 1,3-indane dione in CH2Cl2 has been described in terms of the formation of 1 : 1 molecular complexes. The magnitude of association constants and thermodynamic parameters indicate cooperative interactions of oxygens with the acceptors. The 1H and 13C NMR spectra of the complexes show that gyama-gyama interactions are a major source of ground state stabilization in these complexes.

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This edition testifies to the broad international reach of the journal, with contributions variously concerned with Arctic Indigenous communities, the Métis of Canada, Native Hawaiians and Māori of Aotearoa (New Zealand). Two articles stress the need to work collaboratively and respectfully with Indigenous populations whilst conducting research. The first, by Gwen Healey, notes the increased interest in health research in the Arctic, particularly with Inuit populations. Healy seeks to add to the growing body of literature concerned with Indigenous ways of knowing by highlighting Inuit concepts that inform an effective Arctic research model. The second, by primary author Peter Hutchinson and a range of co-contributors, highlights the ways in which Métis collaborators working in health developed a participatory Indigenous research method that was unique in that it foregrounded Métis relationships and relationality. In so doing, the researchers were able to give substance to otherwise staid policy statements about the need for good ethical research conduct.

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Differential scanning calorimetric studies on ammonium perchlorate have been carried out. The enthalpy values for the phase transition endotherm and the two exotherms have been reported in the present communication. A new method has been developed for the estimation of kinetic parameters from DSC the mograms. The values for activation energy as calculated by the above method for low temperature and high temperature exotherms are in close agreement with literature values. The present studies also confirm the presence of small exothermic peaks at the initial stages of high temperature exotherm. Explanation for the same has been given.

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The effect of past mechanical history on the subsequent thermal decomposition kinetics of sodium, potassium, rubidium and caesium perchlorates, has been investigated. At low temperatures the decomposition of all these salts is significantly sensitized by pre-compression. At high temperatures, however, prior compression results in a lowered decomposition rate in the case of potassium, rubidium and caesium perchlorates and in an increase in the thermal reactivity of sodium perchlorate. The high temperature behaviour is shown to be an indirect consequence of the low temperature behaviour. The difference in behaviour between sodium perchlorate and the other alkali metal perchlorates is explained on the basis of the stability of the respective chlorates, formed during the low temperature decomposition. This is substantiated by experiments which show that the addition of sodium chlorate to sodium perchlorate brings about a sensitization while potassium perchlorate admixed with potassium chlorate results in a desensitization at high temperatures.

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The explosive sensitivity of methylammonium perchlorates has been investigated by differential thermal analysis, thermogravimetric analysis, mass spectrometry and explosion delay experiments. The decomposition temperature of these compounds increases in the order CH3NH3ClO4>(CH3)2NH2ClO4>(CH3)3NHClO4. The activation energy shows the reverse order, indicating thereby that the stability increases with increasing substitution. Mass spectrometric investigation, however, suggests an increasing reactivity with increasing substitution. A possible explanation for such behaviour is proposed. It appears that explosion delay is correlated with thermal decomposition and impact sensitivity.

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The ethylene biosynthesis inhibitor, 1-methylcyclopropene (1-MCP), has been commercially used to extend the storage life of European pear fruit and to allow shipment to distant markets. However, the influence of 1-MCP on the ability of fruit to ripen to an acceptable sensory quality has not been investigated in 'Bartlett' pear, one of the most aromatic of pear fruit. In the current study, early-, mid- and late-season 'Bartlett' pear fruit were treated with 0.6μLL-1 1-MCP at 0°C for 24h, 100μLL-1 ethylene at 20°C for 24h, or untreated before immediate transfer to 20°C for ripening until eating soft (13N firmness). Fruit from each treatment were subjected to objective and sensory quality evaluation once ripe. Sensory quality showed differences related to harvest maturity; the importance of harvest maturity depended on the treatment. Treatment with 1-MCP effectively slowed fruit ripening and therefore extended postharvest life, but also resulted in fully ripened pears with more desirable sensory traits, as compared with ethylene-treated and untreated pears. The enhanced sensory quality was related to higher sweetness, juiciness and pear aroma and reduced fermented aroma, gritty texture and tart taste. In addition, the sensory profiles of 1-MCP-treated pears were more stable among fruit from the three harvest dates than the ethylene-treated pears, which exhibited very different sensory profiles between early- and late-season fruits. © 2015 Elsevier B.V.

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This edition includes a diverse range of contributions that collectively illustrate two elevated concerns of critical Indigenous studies: First, an interest in establishing ways and means of conducting ethical research with Indigenous communities; and second, critically engaging with constructions of Indigeneity. The first article, by Craig Sinclair, Peter Keelan, Samuel Stokes, Annette Stokes and Christine Jefferies-Stokes, examines the increasingly popular use of participatory video (PV) as a means of engagement, in this case with children in remote Aboriginal communities as participants in health research. The authors note that, whilst not without methodological disadvantages, the PV method, with its flexibility to respond to community priorities is particularly well suited to research with remote Aboriginal communities.

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While many placental herpesvirus genomes have been fully sequenced, the complete genome of a marsupial herpesvirus has not been described. Here we present the first genome sequence of a metatherian herpesvirus, Macropodid herpesvirus 1 (MaHV-1).

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A5-GMR-1 is a synchronous stream cipher used to provide confidentiality for communications between satellite phones and satellites. The keystream generator may be considered as a finite state machine, with an internal state of 81 bits. The design is based on four linear feedback shift registers, three of which are irregularly clocked. The keystream generator takes a 64-bit secret key and 19-bit frame number as inputs, and produces an output keystream of length between $2^8$ and $2^{10}$ bits. Analysis of the initialisation process for the keystream generator reveals serious flaws which significantly reduce the number of distinct keystreams that the generator can produce. Multiple (key, frame number) pairs produce the same keystream, and the relationship between the various pairs is easy to determine. Additionally, many of the keystream sequences produced are phase shifted versions of each other, for very small phase shifts. These features increase the effectiveness of generic time-memory tradeoff attacks on the cipher, making such attacks feasible.

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1-Acyl-2-succinyl glycero-3-phosphorylcholine (GPC) was synthesized and its properties described. Although 1-acyl-2-succinyl GPC is a good substrate for succinate dehydrogenase, experiments on the incorporation of [2,3-14C]succinate into mitochondrial lipids gave no evidence to indicate that it is an intermediate in the enzymic oxidation of succinate to fumarate, as has been suggested earlier.

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This paper presents a systematic method of investigating the existence of limit cycle oscillations in feedback systems with combined integral pulse frequency-pulse width (IPF-P/V) modulation. The method is based on the non-linear discrete equivalence of the continuous feedback system containing the IPF-PW modulator.