Search results for "EXCLUSION"

Synthesis, characterisation and properties of α,β-poly(N-2-hydroxyethyl)-dl-aspartamide-graft-maleic anhydride precursors and their stimuli-responsiv…

2009

Abstract A family of poly(amino acid)-maleic anhydride hydrogels were designed and synthesized. Water soluble polymeric precursors were prepared by partially substituting the hydroxyl groups of the α,β-poly( N -2-hydroxyethyl)- dl -aspartamide backbone with maleic anhydride, so as to provide double bonds for crosslinking and carboxylic acid groups for pH and electric field responsiveness. Reaction conditions (reactive mixture composition and catalysis) were systematically varied in order to obtain PHEA–MA precursors with different and reliable graft-maleic anhydride levels. PHEA–MA precursors were characterised by titration, Nuclear Magnetic Resonance ( 1 H NMR), Fourier-Transformed Infrare…

Systematic investigation of functional core variation within hyperbranched polyglycerols

2008

A novel series of hyperbranched polyether polyols with various n-alkyl amine cores (mono- and bifunctional) and photoactive cores (benzylamine and 1-naphthylmethylamine) have been prepared. Polymerization of glycidol was carried out in two ways, starting directly from primary amine initiators and from bisglycidolized amine initiators. NMR spectroscopy and size exclusion chromatography (SEC) showed good control over the molecular weights only, when bisglycidolized amines were used. Molecular weights and polydispersity of the hyperbranched polyglycerols prepared with these initiator-cores were in the range of 1600 to 8400 g/mol and of 1.5 to 2.5, respectively. MALDI-ToF mass spectrometry conf…

Fractal calibration in size-exclusion chromatography

2003

Abstract The elution behaviour of different polymer–solvent systems in three types of organic columns for SEC has been compared and interpreted. The experimental data show that the classical universal calibration is not accomplished. Deviations from a unique curve are observed due to the binary and ternary interactions between the components of the system (solvent, polymer and gel) which results on secondary mechanisms accompanying the main pure or “ideal” SEC separation mechanism. Both, enthalpic and entropic effects are interpreted in terms of the swelling and crosslinking degrees of the gel packings, and are also related with the fractal characteristics of their surfaces, such as the fra…

Influence of gamma-irradiation on thermally-induced mesoscopic gelation of degalactosylated xyloglucans

2014

Thermoresponsive degalactosylated xyloglucans have been already proposed as in situ gelling scaffolds for tissue engineering, due to their reversible macroscopic thermal gelation at body temperature and biodegradability. The highly branched, hydroxyl group-rich molecular structure renders xyloglucans interesting raw materials also in the form of micro/nanoparticles for application as nanoscalar drug delivery devices in cosmetic and pharmaceutical formulations. Owing to their natural source, xyloglucans show high average molecular weight, broad molecular weight distribution and poor water solubility, as large and compact aggregates usually form via inter-molecular hydrogen bonding. Co-60 gam…

Nucleoside phosphotransferase of chick embryo

1979

This paper describes a purification procedure and some properties of a nonspecific nucleoside phosphotransferase of chick embryo, an activity which catalyzes the transfer of chick embryo, an activity which catalyzes the transfer of the phosphate ester from a deoxyribonucleotide or a pyrimidine ribonucleotide to a deoxyribonucleoside acceptor. The enzyme is very unstable to heat, dilution and dialysis and it is almost entirely inactivated by DEAE-cellulose chromatography or gel filtration. A marked enhancement in its stability is caused by numerous nucleotides. In these experiments at least 920-fold purification was obtained by using dTTP (50 microM) as nucleotide protector. The enzyme, puri…

Studies on the Process of Formation, Nature and Stability of Binding Sites in Molecularly Imprinted Polymers

2002

AbstractIn Molecular Imprinting the nature of the templated binding sites and the mechanism of their formation are still poorly understood. For this reason our groups are carrying out fundamental studies concerning known imprinting protocols, with the primary aim of shedding light on the role of the template in the different steps of the polymerisation, from the formation of primary chains to the build-up of the porous structure. In this paper we report our initial results concerning copolymers of methacrylic acid (MAA) and ethyleneglycol dimethacrylate (EDMA) and their formation in presence or absence of the templates 9-ethyladenine, ametryn or terbutylazine. Monitoring the monomer disappe…

Multivariate correlation between13C and31P NMR spectral data on dissolved lignin and the combustion properties of kraft black liquor

1999

Junk food’ o healthy food? Il cibo, la cultura, i costi sociali: una questione non solo americana

2020

Abstract Il contributo si interroga sul rapporto tra cibo e città, tra pianificazione e consumi alimentari e tra junk food e salute, riflettendo su come il cibo, patrimonio culturale comune, abbia profonde relazione con la qualità della vita delle persone, con ampi settori economici, con il paesaggio urbano e sociale, con la pianificazione: il cibo, anche per essere snodo culturale e simbolico, è un ambito intermedio da cui partire in termini etici e collaborativi. Emblematico è il caso americano, il Paese propulsore del fast food, per i caratteri del sistema economico e per la natura del territorio della Confederazione e di alcune grandi città, come Los Angeles e New York City.

The good, the bad and the ugly: images of the foreigner in contemporary criminal law

2018

Since the end of the Second World War, the criminal law of Western states has tried to legitimate itself, in basically democratic-republican terms, as primarily addressed towards citizens. During approximately the last 20 years, however, new dimensions of criminal law have emerged, which refer paradigmatically (not to the citizen, but) to the foreigner and subject him/her to worse legal treatment than that which is considered legitimate when either citizens or ‘good’ foreigners are concerned. Next to the ideal-type of the citizen criminal law (also applicable, by assimilation, to the ‘good’ foreigner) a criminal law for ‘ugly’ mass-foreigners (crimmigration) and one for ‘bad’ foreigners (en…

L'exclusion des ministres communistes du gouvernement en mai 1947

2022

Le 4 mai 1947, les ministres communistes sont exclus du gouvernement, auquel ils participaient depuis la Libération. Dans un contexte de conflictualité sociale et d'exacerbation des tensions géopolitiques, à l'aube de la guerre froide, l'alliance tripartite entre le PCF, la SFIO et le MRP semblait vouée à la rupture. Celle-ci n'était toutefois pas pensée comme définitive par les communistes en mai 1947, de telle sorte que l'on peut distinguer deux dynamiques qui participent successivement au processus d'isolement des communistes : une « exclusion positive » de ces derniers par le reste du gouvernement dans un premier temps, avec la conviction de pouvoir y revenir rapidement, puis un phénomè…