Les harraga algériens

Des Algériens, principalement des jeunes hommes, tentent de quitter leur pays, sans passeport ni visa, sur des barques, au péril de leur vie. En dialecte maghrébin, on nomme ces candidats à l’émigration harraga (les “brûleurs”), car ils “brûlent” les frontières et les étapes nécessaires à une migration légale. En outre, s’ils arrivent en Europe, ils détruisent, ils “brûlent” leurs papiers d’identité pour tenter d’échapper à l’expulsion. Après les hittistes des années 1980 et ceux qui ont rejoint les groupes islamistes armés durant le conflit des années 1990, les harraga sont érigés au rang de figure symbolisant le désespoir de la jeunesse algérienne durant les années 2000. Ils sont invoqués comme preuve ultime des dysfonctionnements qui touchent le pays. (Premier paragraphe

Heritage science contribution to the understanding of meaningful khipu colours

Funding: Financial support by the Access to Research Infrastructures activity in the Horizon 2020 Programme of the EU (IPERION HS Grant Agreement n.871034) is gratefully acknowledged.This work is the first scientific study of khipu dyes and inorganic mordants and auxiliaries, paving the way for a new approach to understanding khipus’ meaningful materiality, technology, and colours. Khipus have usually been described as “Andean knotted records”, but they are much more than complex knotted cords: a great part of the information encoded resides in khipus’ incredible colours. The objects of this study are two Wari khipus, 1932.08.0001 and 1932.08.0002, now at the Museum of World Culture in Gothenburg, Sweden. After a morphological study of the khipus, the objects were imaged with multiband imaging (MBI) as an aid for the sampling decisional process. The khipus were then analysed non-invasively by X-ray fluorescence (XRF) spectroscopy on selected areas of particular interest. The khipus were consequently sampled for elemental characterisation by micro-XRF, and liquid chromatography coupled with high-resolution mass spectrometry (HPLC–HRMS) for characterising the organic dye composition. This paper presents a part of the results of the project “Meaningful materials in the khipu code”, with the intent to shed light on the difficulties and possibilities of investigating khipu colours and dyestuffs. MBI and XRF revealed unforeseeable structural characteristics, such as remnants from a heavily degraded thread in an area of missing thread wrapping and a dual-coloured thread that was previously deemed single-coloured. The organic dyes identified by HPLC–HRMS comprised indigoids, cochineal, and an unknown flavonoid-based dyestuff. XRF of the inorganic components revealed associations of several elements with specific colours.Publisher PDFPeer reviewe

Dyes in History and Archaeology 41: Reflections on the Conference and Its Assembly of Articles

Editorial: no abstract availabl

Synthesis and properties of bis-porphyrin molecular tweezers: effects of spacer flexibility on binding and supramolecular chirogenesis

Ditopic binding of various dinitrogen compounds to three bisporphyrin molecular tweezers with spacers of varying conformational rigidity, incorporating the planar enediyne (1), the helical stiff stilbene (2), or the semi-rigid glycoluril motif fused to the porphyrins (3), are compared. Binding constants Ka = 104–106 M?1 reveal subtle differences between these tweezers, that are discussed in terms of porphyrin dislocation modes. Exciton coupled circular dichroism (ECCD) of complexes with chiral dinitrogen guests provides experimental evidence for the conformational properties of the tweezers. The results are further supported and rationalized by conformational analysis

Pappersuppstrykning av trätjära : förstudie av en enkel metod för identifiering av kvalitetsmarkörer hos trätjära

Förstudien beskriver hur uppstrykning av tjära på vanligt vitt skrivarpapper kan ge direkt information om filmbildande och fuktskyddande förmåga utifrån ett antal markörer såsom partikelinnehåll, torkbeteende och färg. En enkel och nästintill kostnadsfri bedömning av tjärans egenskaper är tillgänglig för alla till skillnad från avancerad instrumentation och kunskaper som vanligtvis krävs vid analys av tjärans innehåll. Användaren av tjäran kan få information som kan vara användbar vid bedömning av till exempel förväntat underhålls-intervall, om det kan krävas flera strykningar för ett gott fuktskydd samt relaterade kostnader. Förstudien går inte in på parametrar såsom substratets egenskaper, applicerings-teknik, nedbrytningsfaktorer och ger heller inga konkreta prognoser om underhållsintervall vid användning av tjära med olika egenskaper

Modulation of Molecular Properties : Host–Guest Interactions for Structural Analysis and Chemical Reactions

This thesis concerns the construction, use and modulation of various host–guest systems, from small bispidines for binding of inorganic ions to bisporphyrin clips for supramolecular systems. Small flexible molecules undergo fast conformational movements when in solution. These conformational movements generate time-averaged population-weighted chemical shifts, coupling constants and NOEs when analysed by NMR spectroscopy. A bisporphyrin clip was designed to be used as a host for restriction of conformational movements of small flexible molecules by ditopic metal-ligand binding. Based on conformational analysis in combination with NMR analysis of molecular flexibility in solution (NAMFIS), the relative stereochemistry of flexible alditol-derived diamines containing three or four consecutive stereocentres could be determined. To further explore the idea of conformational deconvolution via host–guest binding, two flexible molecular tweezers with photoswitchable moieties were developed. Upon photoswitching cis/trans isomerisation facilitates the opening and closing of these bisporphyrin hosts. A guest molecule could then be exposed to a “catch and stretch” or “catch and release” effect. Preliminary studies have shown that photoisomerisation of the constructed systems is possible without photodecomposition and preliminary binding studies have been conducted. Controlled modulation of molecular conformations is of interest especially if the conformational steering activates a unit working as a nucleator in a larger structure or facilitates a reaction. The protonation-triggered modulation of bispidine conformations has been investigated. In addition to previously reported conformations we have observed that upon diprotonation a bispidine derivative can be driven into the unusual boat-boat conformation. Finally, the unexpected formation of persistent organic radicals with a cyclophane motif from the reaction of N,N´-diphenyl-1-5-diazacyclooctane and AgBF4 is described. Interestingly, these diradicals exhibit features such as intramolecular π-stacking without lateral displacement and also intramolecular spin pairing.

Modulation of Molecular Properties : Host–Guest Interactions for Structural Analysis and Chemical Reactions

This thesis concerns the construction, use and modulation of various host–guest systems, from small bispidines for binding of inorganic ions to bisporphyrin clips for supramolecular systems. Small flexible molecules undergo fast conformational movements when in solution. These conformational movements generate time-averaged population-weighted chemical shifts, coupling constants and NOEs when analysed by NMR spectroscopy. A bisporphyrin clip was designed to be used as a host for restriction of conformational movements of small flexible molecules by ditopic metal-ligand binding. Based on conformational analysis in combination with NMR analysis of molecular flexibility in solution (NAMFIS), the relative stereochemistry of flexible alditol-derived diamines containing three or four consecutive stereocentres could be determined. To further explore the idea of conformational deconvolution via host–guest binding, two flexible molecular tweezers with photoswitchable moieties were developed. Upon photoswitching cis/trans isomerisation facilitates the opening and closing of these bisporphyrin hosts. A guest molecule could then be exposed to a “catch and stretch” or “catch and release” effect. Preliminary studies have shown that photoisomerisation of the constructed systems is possible without photodecomposition and preliminary binding studies have been conducted. Controlled modulation of molecular conformations is of interest especially if the conformational steering activates a unit working as a nucleator in a larger structure or facilitates a reaction. The protonation-triggered modulation of bispidine conformations has been investigated. In addition to previously reported conformations we have observed that upon diprotonation a bispidine derivative can be driven into the unusual boat-boat conformation. Finally, the unexpected formation of persistent organic radicals with a cyclophane motif from the reaction of N,N´-diphenyl-1-5-diazacyclooctane and AgBF4 is described. Interestingly, these diradicals exhibit features such as intramolecular π-stacking without lateral displacement and also intramolecular spin pairing.

Modulation of Molecular Properties : Host–Guest Interactions for Structural Analysis and Chemical Reactions

This thesis concerns the construction, use and modulation of various host–guest systems, from small bispidines for binding of inorganic ions to bisporphyrin clips for supramolecular systems. Small flexible molecules undergo fast conformational movements when in solution. These conformational movements generate time-averaged population-weighted chemical shifts, coupling constants and NOEs when analysed by NMR spectroscopy. A bisporphyrin clip was designed to be used as a host for restriction of conformational movements of small flexible molecules by ditopic metal-ligand binding. Based on conformational analysis in combination with NMR analysis of molecular flexibility in solution (NAMFIS), the relative stereochemistry of flexible alditol-derived diamines containing three or four consecutive stereocentres could be determined. To further explore the idea of conformational deconvolution via host–guest binding, two flexible molecular tweezers with photoswitchable moieties were developed. Upon photoswitching cis/trans isomerisation facilitates the opening and closing of these bisporphyrin hosts. A guest molecule could then be exposed to a “catch and stretch” or “catch and release” effect. Preliminary studies have shown that photoisomerisation of the constructed systems is possible without photodecomposition and preliminary binding studies have been conducted. Controlled modulation of molecular conformations is of interest especially if the conformational steering activates a unit working as a nucleator in a larger structure or facilitates a reaction. The protonation-triggered modulation of bispidine conformations has been investigated. In addition to previously reported conformations we have observed that upon diprotonation a bispidine derivative can be driven into the unusual boat-boat conformation. Finally, the unexpected formation of persistent organic radicals with a cyclophane motif from the reaction of N,N´-diphenyl-1-5-diazacyclooctane and AgBF4 is described. Interestingly, these diradicals exhibit features such as intramolecular π-stacking without lateral displacement and also intramolecular spin pairing.

Strategies for Pollutant Monitoring in Museum Environments

Denna rapport beskriver metoder att undersöka och övervaka luftföroreningar inomhus i en museimiljö. Luftföroreningar i en museimiljö kan komma utifrån, från konstruktionsmaterial inomhus eller från museiföremålen själva. Dessa luftföroreningar kan orsaka skador på föremål genom att påskynda den kemiska nedbrytningen och orsaka till exempel försprödning, korrosion, missfärgning och sprickbildning. Skadliga luftföroreningar kan förekomma både i stora utrymmen som utställningssalar, eller i små täta utrymmen som montrar och förvaringslådor. This project is a collaboration between the Swedish National Heritage Board (Riksantikvarieämbetet) and Nationalmuseum in Stockholm, Sweden. It focuses on monitoring indoor pollutants in museum environments. Pollutants can adversely react with collection objects in large spaces such as galleries and in smaller enclosures like display cases or storage containers

Utvärdering av förvaringsmaterials påverkan på cellulosa : test av en standard under utveckling

Riksantikvarieämbetet och Riksarkivet har tillsammans utvärderat en föreslagen standard för att bedöma materials påverkan på cellulosa. Undersökningarna, i huvudsak accelererad åldring och viskometri av cellulosa, kan vara användbara för många aktörer inom konservering och bevarande. Påverkan på cellulosabaserat kulturarv, så som aktomslag av både papper och textil, kan undersökas på detta vis. Metoden som den föreslagna standarden baseras på finns beskriven i artikeln ”Test for Compatibility with Organic Heritage Materials – A Proposed Procedure” (Strlič et. al. 2010) och innefattar användandet flera ISO-standarder som inte nödvändigtvis varit framtagna för kulturarvsaktörer. Sammantaget visade projektet att den prövade metoden kan vara användbar inom kulturvården, men den kräver en kontrollerad laboratoriemiljö och stor noggrannhet vid utförandet. Projektet har bidragit till kompetensutveckling samt ökad förståelse för både metod och teknik. Vidare kommer erfarenheter från detta projekt att bidra till tolkning av resultat som använder någon av de ingående standarderna