Search results for " meta"
showing 10 items of 9626 documents
Facile and efficient chemical functionalization of aliphatic polyesters by cross metathesis
2016
International audience; An effective preparation of new tailor-made macromolecular materials via a combination of two (atom-efficient) catalytic transformations is reported. First, new aliphatic polyesters with alternated composition have been prepared using a salen aluminum catalyst system. Next, the pendant vinyl moieties in those copolymers have been selectively transformed into various functional groups by metathesis in the presence of homogeneous Grubbs catalysts. The latter metathesis reaction has been optimized in terms of catalytic activity and selectivity, to define the conditions for an effective and safe procedure that does not affect the macromolecular architecture. All polymer …
Polimeryzacja koordynacyjna alkenylosilseskwioksanów i ich kopolimeryzacja z olefinami lub styrenem
2015
Artykuł stanowi kontynuację przeglądu literatury dotyczącej koordynacyjnej polimeryzacji silseskwioksanów (POSS), zawierających zdolne do polimeryzacji wiązanie podwójne, oraz ich kopolimeryzacji głównie zolefinami, a także ze styrenem. Zastosowanie katalizatorów metalocenowych aktywowanych metyloaluminoksanem (MAO) zapewnia efektywną (ko)polimeryzację silseskwioksanów zarówno z olefinami, jak i styrenem. Wprowadzenie do materiału polimerowego komonomeru POSS korzystnie wpływa na właściwości otrzymanych produktów, które cechują się większą odpornością termiczną oraz wytrzymałością mechaniczną niż ich odpowiedniki niezawierające POSS.
Silseskwioksany i ich zastosowanie w syntezie materiałów polimerowych
2015
Artykuł stanowi przegląd literatury dotyczącej syntezy oraz charakterystyki materiałów polimerowych zawierających silseskwioksany (POSS). Przedstawiono metody otrzymywania hybrydowych materiałów polimerowych z udziałem funkcjonalizowanych POSS na drodze click chemistry, polikondensacji, poliaddycji, metatezy z otwarciem pierścienia ipolimeryzacji rodnikowej zarówno konwencjonalnej, jak i kontrolowanej (ATRP).
Political Discourse as Culture and Ideology
2009
This book explores the way in which pronominal relations and rhetorical strategies in political discourse determine the relationship speaker/audience, thus conditioning both the discourse organizational structures and the development of ideological content. The texts themselves are analysed from three different points of view: (i) in terms of Critical Discourse Analysis (CDA); (ii) in terms of rhetorical analysis; (iii) in terms of ideological content. More specifically, the intergration of rhetorical analysis into Critical Discourse Analysis is relevant and allows us to understand the realationship between linguistic structures on the one hand, and how these structures are designed to infl…
Reading figurative images in the political discourse of the British Press
2017
The present work aims to study visual metaphors and multimodal metaphors in the political cartoons published in the British press during the Brexit campaign. The theoretical approach adopted draws upon the theories elaborated by Halliday (), Forceville (; ), Ruiz de Mendoza and Diez (), and Hart (), with the objective of identifying the three analytical steps that lead to the conceptual frames structuring the political event under investigation. Results show the extent to which the visual representation of the Brexit campaign proposes novel and original perspectives of interpretation, and further evidence of the relevance of metaphors and metonymies in the narration of e…
Amphoteric, prevailingly cationic L-arginine polymers of poly(amidoamino acid) structure: Synthesis, acid/base properties and preliminary cytocompati…
2013
A linear amphoteric poly(amidoamino acid), L-ARGO7, is prepared by Michael-type polyaddition of L-arginine with N,N′-methylenebisacrylamide. Chain-extension of acrylamide end-capped L-ARGO7 oligomers with piperazine leads to high-molecular-weight copolymers in which L-arginine maintains its absolute configuration. Acid/base properties of L-ARGO7 polymers show isolectric points of ≈10 and positive net average charges per repeating unit at pH = 7.4 from 0.25 to 0.40. These arginine-rich synthetic polymers possibly share some of the unique biological properties of polyarginine cell-permeating peptides. In vitro tests with mouse embryo fibroblasts balb/3T3 clone A31 show that L-ARGO7 polymers a…
Hetero-difunctional dimers as building blocks for the synthesis of poly(amidoamine)s with hetero-difunctional chain terminals and their derivatives
2012
This article reports on a simple and straightforward preparation method of poly(amidoamine)s (PAAs) with hetero-difunctional chain ends as well as of several up to now hardly obtainable PAA derivatives of biotechnological interest, such as for instance PAAs of controlled molecular weight and narrow polydispersity mono-functionalized at one end with an acrylamide group, PAAs with star-like molecular architecture, graft-PAA-protein conjugates, “tadpole-like” PAA conjugates with hydrophobic moieties able to self assemble into nanoparticles in aqueous media. The key step was to design suitable building blocks consisting of hetero-difunctional dimers (HDDs). In particular, the HDDs considered we…
Additional file 6: of Male breast cancer in BRCA1 and BRCA2 mutation carriers: pathology data from the Consortium of Investigators of Modifiers of BR…
2016
Pathology of invasive MBCs in the general population from SEER and BRCA1 MBCs and ORs in predicting male BRCA1 mutation carrier status. (DOCX 19 kb)
Additional file 6: of Male breast cancer in BRCA1 and BRCA2 mutation carriers: pathology data from the Consortium of Investigators of Modifiers of BR…
2016
Pathology of invasive MBCs in the general population from SEER and BRCA1 MBCs and ORs in predicting male BRCA1 mutation carrier status. (DOCX 19 kb)
Transition metal complexes of tetradentate and bidentate Schiff bases as catalysts for ethylene polymerization: Effect of transition metal and cocata…
2009
This article compares catalytic performance of ethylene polymerization in similar polymerization conditions of transition metal complexes having two ligands [O,N] (phenoxy-imine) and having one tetradentate ligand [O,N,N,O] (salphen or salen). It is shown that the activity of both complex types as well as the product properties depend in the same way on the type of central metal in the complex and on the cocatalyst used. Although the type of ligand has some effect on the catalyst activity, yet it does not control the properties of the obtained products. The vanadium and zirconium complexes, irrespective of the cocatalyst used, yield linear polyethylene with high molecular weight (a few hund…