961 resultados para electronic paper display


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Cancer cachexia is a multidimensional syndrome characterised by wasting, loss of weight, loss of appetite, metabolic alterations, fatigue and reduced performance status. A significant number of patients with advanced cancer develop cachexia before death. There is no identified optimum treatment for cancer cachexia. While the exact mechanism of the action of thalidomide is unclear, it is known to have immunomodulatory and anti-inflammatory properties, which are thought to help reduce the weight loss associated with cachexia. Preliminary studies of thalidomide have demonstrated encouraging results. This review aimed to (1) evaluate the effectiveness of thalidomide, and (2) identify and assess adverse effects from thalidomide for cancer cachexia. Electronic searches were undertaken in CENTRAL, MEDLINE, EMBASE, Web of Science and CINAHL (from inception to April 2011). Reference lists from reviewed articles, trial registers, relevant conference documents and thalidomide manufacturers identified additional literature. This review included randomised controlled trials (RCTs) and non-RCTs. Participants were adults diagnosed with advanced or incurable cancer and weight loss or a clinical diagnosis of cachexia who were administered thalidomide. All titles and abstracts retrieved by electronic searching were downloaded to a reference management database. Duplicates were removed and the remaining citations were read by two review authors and checked for eligibility. Studies that were deemed ineligible for inclusion had clear reasons for exclusion documented. Data were extracted independently by two review authors for all eligible studies. While a meta-analysis was planned for this review, this was not possible due to the small number of studies included and high heterogeneity among them. Thus a narrative synthesis of the findings is presented. The literature search revealed a dearth of large, well conducted trials in this area. This has hindered the review authors' ability to make an informed decision about thalidomide for the management of cancer cachexia. At present, there is insufficient evidence to refute or support the use of thalidomide for the management of cachexia in advanced cancer patients. The review authors cannot confirm or refute previous literature on the use of thalidomide for patients with advanced cancer who have cachexia and there is inadequate evidence to recommend it for clinical practice. Additional, well conducted, large RCTs are needed to test thalidomide both singularly and in combination with other treatment modalities to ascertain its true benefit, if any, for this population. Furthermore, one study (out of the three reviewed) highlighted that thalidomide was poorly tolerated and its use needs to be explored further in light of the frailty of this population

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Norms constitute a powerful coordination mechanism among heterogeneous agents. In this paper, we propose a rule language to specify and explicitly manage the normative positions of agents (permissions, prohibitions and obligations), with which distinct deontic notions and their relationships can be captured. Our rule-based formalism includes constraints for more expressiveness and precision and allows to supplement (and implement) electronic institutions with norms. We also show how some normative aspects are given computational interpretation. © 2008 Springer Science+Business Media, LLC.

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The basic concepts and phenomenology of wave mixing and harmonic generation are reviewed in context of the recent advances in the enhanced nonlinear activity in metamaterials and photonic crystals. The effects of dispersion, field confinement and phase synchronism are illustrated by the examples of the on-purpose designed artificial nonlinear structures. (c) 2012 Wiley Periodicals, Inc. Int J RF and Microwave CAE 22:469482, 2012.

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In this paper, we report a fully ab initio variational Monte Carlo study of the linear and periodic chain of hydrogen atoms, a prototype system providing the simplest example of strong electronic correlation in low dimensions. In particular, we prove that numerical accuracy comparable to that of benchmark density-matrix renormalization-group calculations can be achieved by using a highly correlated Jastrow-antisymmetrized geminal power variational wave function. Furthermore, by using the so-called "modern theory of polarization" and by studying the spin-spin and dimer-dimer correlations functions, we have characterized in detail the crossover between the weakly and strongly correlated regimes of this atomic chain. Our results show that variational Monte Carlo provides an accurate and flexible alternative to highly correlated methods of quantum chemistry which, at variance with these methods, can be also applied to a strongly correlated solid in low dimensions close to a crossover or a phase transition.

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In a recent article (J. Am. Chem. Soc. 2011, 133, 20186) we investigated the initial spatial distribution of dry excess electrons in a series of room-temperature ionic liquids (RTILs). Perhaps unexpectedly, we found that in some alkylammonium-based systems the excess negative charge resided on anions and not on the positive cations. Following on these results, in the current paper we describe the time evolution of an excess electronic charge introduced in alkylammonium- and pyrrolidinium-based ionic liquids coupled with the bis(trifluoromethylsulfonyl)amide ([TfN]) anion. We find that on a 50 fs time scale an initially delocalized excess electron localizes on a single [TfN] anion which begins a fragmentation process. Low-energy transitions have a very different physical origin on the several femtoseconds time scale when compared to what occurs on the picosecond time scale. At time zero, these are intraband transitions of the excess electron. However after 40 fs when the excess electronic charge localizes on a single anion, these transitions disappear, and the spectrum is dominated by electron-transfer transitions between the fragments of the doubly charged breaking anion. © 2013 American Chemical Society.