101 resultados para 286


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The chemical equilibrium of mutual interconversions of tert-butylbenzenes was studied in the temperature range 286 to 423 K using chloroaluminate ionic liquids as a catalyst. Enthalpies of five reactions of isomerization and transalkylation of tert-butylbenzenes were obtained from temperature dependences of the corresponding equilibrium constants in the liquid phase. Molar enthalpies of vaporization of methyl-tert-butylbenzenes and 1,4-ditert-butylbenzene were obtained by the transpiration method and were used for a recalculation of enthalpies of reactions and equilibrium constants into the gaseous phase. Using these experimental results, ab initio methods (B3LYP and G3MP2) have been tested for prediction thermodynamic functions of the five reactions under study successfully. Thermochemical investigations of tert-butyl benzenes available in the literature combined with experimental results have helped to resolve contradictions in the available thermochemical data for tert-butylbenzene and to recommend consistent and reliable enthalpies of formation for this compound in the liquid and the gaseous state.

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This paper examines the link made on occasion between the concept of dignity and substantive equality; it is further noted that dignity can have very different meanings in different contexts. While the notion of dignity does not often play a substantive role in the resolution of decisions, sometimes the underlying understanding of dignity does matter. However, in all cases, judges should avoid the temptation to rely on unarticulated value judgments or subjective notions of dignity. When judges make reference to dignity, they should articulate the values underpinning their conception of it.

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Following its transition to democracy from an authoritarian military rule marked by gross violations of human rights, Nigeria established the Human Rights Violations Investigations Commission (HRVIC) in 1999. This paper critically examines the contributions of the HRVIC, popularly known as the ‘Oputa Panel,’ to the field of transitional justice and the rule of law. It sets out the process of establishing the Commission, its mandate and how this mandate was interpreted during the course of the Commission’s work. The challenges faced by the Oputa Panel, particularly those that relate to its legal status and relationship with the judiciary, are analyzed in an attempt to draw useful guidelines from these challenges for other truth commissions. Recourse by powerful individuals to the judicial process in a bid to shield themselves from the HRVIC merits particular review as it raises questions regarding the transformation of the judiciary and the rule of law in the wake of an authoritarian regime.

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Dipeptidyl peptidase IV (DPP IV) is the primary inactivator of glucoregulatory incretin hormones. This has lead to development of DPP IV inhibitors as a new class of agents for the treatment of type 2 diabetes. Recent reports indicate that other antidiabetic drugs, such as metformin, may also have inhibitory effects on DPP IV activity. In this investigation we show that high concentrations of several antidiabetic drug classes, namely thiazolidinediones, sulphonylureas, meglitinides and morphilinoguanides can inhibit DPP IV The strongest inhibitor nateglinide, the insulin-releasing meglitinide was effective at low therapeutically relevant concentrations as low as 25 mu mol/l. Nateglinide also prevented the degradation of glucagon-like peptide-1 (GLP-1) by DPP IV in a time and concentration-dependent manner. In vitro nateglinide and GLP-1 effects on insulin release were additive. In vivo nateglinide improved the glucose-lowering and insulin-releasing activity of GLP-1 in obese-diabetic ob/ob mice. This was accompanied by significantly enhanced circulating concentrations of active GLP-1(7-36)amide and lower levels of DPP IV activity. Nateglinide similarly benefited the glucose and insulin responses to feeding in ob/ob mice and such actions were abolished by coadministration of exendin(9-39) and (Pro(3))GIP to block incretin hormone action. These data indicate that the use of nateglinide as a prandial insulin-releasing agent may partly rely on inhibition of GLP-1 degradation as well as beta-cell K-ATP channel inhibition. (C) 2007 Elsevier B.V. All rights reserved.

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Within the sociology of religion there has emerged a discourse on spirituality that views contemporary developments as involving the assertion of individuals’ self-authority. This perspective’s theoretical roots have been persistently criticised for their conceptualisation of agency; in contrast, this paper draws upon Bourdieu’s concept of strategy to examine action in an English religious network of the sort often classified ‘New Age’. In particular, one informant is discussed in order to provide focus for an understanding of what Lahire calls sociology at the level of the individual. Her actions, better explained as strategic improvisations than as choices made on the basis of self-authority, help to illuminate the peculiarities of this religious setting, which is characterised in terms of ‘nonformativeness’. By emphasising social contextualisation, this approach addresses people’s meaningful actions in a way that may be applied not only more widely within the religious field but also in other fields of action.

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Purpose – The purpose of this paper is to identify the main practitioners, goods, customers and locations of secondhand marketing activities in late medieval England. It questions how important was the economic role played by such markets and what was the interaction with more formal market structures?

Design/methodology/approach – A broad range of evidence was examined, covering the period from 1200 to 1500: regulations, court rolls, wills, manorial accounts, literature, and even archaeology. Such material often provided mere scraps of information about marginal marketing activity and it was important to recognise the severe limitations of the evidence. Nevertheless, a wide survey of the available sources can give us an insight into medieval attitudes towards such trade, as well as reminding us that much marketing activity occurred beyond the reach of the surviving documentation.

Findings – Late medieval England had numerous outlets for secondhand items, from sellers of used clothes and furs who wandered the marketplaces to craftsmen who recycled and mended old materials. Secondhand marketing was an important part of the medieval makeshift economy, serving not only the needs of the lower sectors of society but also those aspiring to a higher status. However, it is unlikely that such trade generated much profit and the traders were often viewed as marginal, suspicious and even fraudulent.

Originality/value – There is a distinct lack of research into the extent of and significance of medieval secondhand marketing, which existed in the shadowy margins of formal markets and is thus poorly represented in the primary sources. A broad-based approach to the evidence can highlight a variety of important issues, which impact upon the understanding of the medieval English economy.

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The enhanced optical properties of metal films periodically perforated with an array of sub-wavelength size holes have recently been widely studied in the field of surface plasmon optics. The ability to design the optical transmission of such nanostructures, which act as plasmonic crystals, by varying their geometrical parameters gives them great flexibility for numerous applications in photonics, opto-electronics, and sensing. Transforming these passive optical elements into devices that may be actively controlled has presented a new challenge. Here, we report on the realization of an electrically controlled nanostructured optical system based on the unique properties of surface plasmon polaritonic crystals in contact with a liquid crystal (LC) layer. We discuss the effect of LC layer modulation on the surface plasmon dispersion, the related optical transmission and the underlying mechanism. The reported effect may be used to achieve active spectral tuneability and switching in a wide range of applications.

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Although members of the p63 family of transcription factors are known for their role in the development and differentiation of epithelial surfaces, their function in cancer is less clear. Here, we show that depletion of the Delta Np63 alpha and beta isoforms, leaving only Delta Np63 gamma, results in epithelial to mesenchymal transition (EMT) in the normal breast cell line MCF10A. EMT can be rescued by the expression of the Delta Np63 alpha isoform. We also show that Delta Np63 gamma expressed in a background where all the other Delta Np63 are knocked down causes EMT with an increase in TGF beta-1, -2, and -3 and downstream effectors Smads2/3/4. In addition, a p63 binding site in intron 1 of TGF beta was identified. Inhibition of the TGF beta response with a specific inhibitor results in reversion of EMT in Delta Np63 alpha- and beta-depleted cells. In summary, we show that p63 is involved in inhibiting EMT and reduction of certain p63 isoforms may be important in the development of epithelial cancers.