33 research outputs found

    Selection and Control of Individual Domain Walls in Nanowire Arrays via Asymmetric Depinning Fields

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    Artificially inscribed notches are often used to pin domain walls (DWs) in ferromagnetic nanowires. The process of selecting and moving the trapped DW in nanowire arrays is an important step for potential applications. The chirality of a DW leads to a pair of pinning positions at the inscribed notches, which can be modeled by a symmetric double well. The depinning field depends on the side of the well, the DW is trapped with respect to the applied field direction, and the DWs can also be transitioned between the two wells without depinning. We demonstrate how manipulating the double well improves the DW selectivity and control in wire arrays containing multiple DWs

    Chemical analyses of extremely degraded wood using analytical pyrolysis and inductively coupled plasma atomic emission spectroscopy

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    Alum-treated archaeological woods from the Oseberg collection, excavated and treated in the early 1900s demonstrate an extreme deterioration, only discovered in the past decade. This research was aimed at understanding the characteristics of the naturally aged material through chemical analyses of both organic and inorganic components, in order to provide information for the preservation/conservation of these precious objects. Analytical pyrolysis-gas chromatography/mass spectrometry with in situ silylation using hexamethyldisilazane (Py(HMDS)-GC/MS) and inductively coupled plasma-atomic emission spectroscopy (ICP-AES) were used to investigate a set of samples of alum-treated archaeological wood and untreated archaeological wood. Sound woods of the same species were also analysed in order to compare the results. Results from Py(HMDS)-GC/MS analyses of alum-treated woods from Oseberg showed an extreme depletion of carbohydrates and a highly deteriorated lignin network. The majority of the lignin had undergone oxidation reactions, illustrated by high relative amounts of acidic pyrolysis products. In particular, p-hydroxy-benzoic acid was detected for the first time as a degradation product of archaeological wood. Results from ICP-AES showed variable concentrations of aluminium and potassium from the alum treatment, as well as iron, copper, zinc and calcium. The extent of oxidation observed by Py(HMDS)-GC/MS appeared to correlate with relative amounts of iron and calcium in the samples, which may suggest that degradation promoted by iron compounds is inhibited in the presence of calcium compounds. The results obtained for a sample of archaeological wood treated with alum salts five years ago showed that chemical deterioration of lignin had already begun, mainly involving depolymerisation reactions, though only a slight increase in oxidation was evident. In addition to increased insight into potential deterioration reactions, occurring in a complex material such as alum-treated archaeological wood, it was possible to relate the degree of chemical degradation of the Oseberg woods to their visual condition (observed with the naked eye). © 2015 Elsevier B.V

    Powdery Pigments from the Original Materials Collection of Munch Conservation Treatment and Analytical Characterization

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    This contribution focuses on the study and preservation of 14 out of 35 powdery pigments in original paper bags. These are part of the artist materials reference collection at the Munch Museum in Oslo. The challenge of this study consists in the lack of information about the year of purchase of the pigments and its content. Some information is provided by the manufacturer s handwritten notes, some of them are, however, unreadable and a few bags have no information, nor on manufacturer or on its content. Munch has used at least four known Oslo based manufactures and some of the information from these paper bags could help giving at least some dating. Some relate to the name change of the city, from Kristiania to Oslo in 1925. Other information relates to the manufacturer s history, writing style, logos, addresses and telephone numbers. So far, the dating is the following 1900 1925, 1922 1925 or after 1922. Some of the original paper bags, were in a very poor state and some containing highly hazardous pigments. The damages were significant and some relates to previous handling; such as tears, others had large, corroded holes on bottom or sides. All these required conservations to enable further storage of the pigments and to prevent additional damage from handling. Several bags were also stained with its powdery pigment which compromised the conservation by choosing a non aqueous treatment. Heat activated adhesive with BEVA 371 film lined with hand colored Japanese tissues was applied for bridging of tears and infills of holes. 14 different pigments of white, yellow, red, blue and green colours were analyzed using ATR FTIR, pXRF, SEM EDS, XRD, Raman spectroscopy and synchrotron based far infrared spectroscopy for understanding their chemical composition. The analytical characterization shows a palette of pigments and lakes as one could expect from the first half of 20th century. Apart from common pigments and extenders such as chrome yellow, cadmium yellow, Prussian blue, barium sulfate and others, an amorphous silicate was found which is assumed to create texture effects or is the raw material for production of waterglass. One of the cadmium yellow samples has a remarkable content of cadmium carbonate which may be related to the production method and or the degradation of cadmium yellow. In one sample a hydrated calcium carbonate occurs. This study opens future research regarding this artist s collection, adding new knowledge about Munch s own use of art materials but also in general on modern paint material

    Aminoethyl substitution enhances the self-assembly properties of an aminocellulose as a potential archaeological wood consolidant

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    The 6-deoxy-6-aminocelluloses—or “aminocelluloses”—are a class of synthetic natural cellulose derivatives which are mostly aqueous soluble and have excellent film-forming properties. Recent studies have connected these properties at the molecular level with protein-like self-associative behaviour for a range of aminocelluloses including a 6-deoxy-6-(ω-aminoethyl) aminocellulose AEA-1 with the association being a two-stage process—a reversible oligomerisation followed by further (semi-reversible) aggregation into larger structures. Here, we synthesise and compare a new 6-deoxy-6-(ω-aminoethyl) aminocellulose AEA-1â€Č with different degree of substitution with one with further alkyl derivatisation, namely 6-deoxy-6-(ω-hydroxyethyl) aminocellulose HEA-1â€Č. As with AEA-1, sedimentation velocity and sedimentation equilibrium in the analytical ultracentrifuge still show a two-stage process for both AEA-1â€Č and HEA-1â€Č, with the latter giving higher molar masses. The consequences of these properties for use as consolidants for archaeological wood are considered

    Choice of psychological coping in laryngectomized, head and neck squamous cell carcinoma patients versus multiple sclerosis patients

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    To be treated for cancer must be a frightening experience. Yet quality of life (QoL) of successfully treated cancer patients seems to be relatively similar in comparison with QoL of a general population, with psychological coping partly responsible for this finding. When measuring choice of coping, the nature of coping score levels constituting appropriate scores, and whether score levels rely on the context of the disease has not been settled. We have studied the COPE coping responses as related to disease in successfully treated head and neck squamous cell carcinoma (HNSCC) patient groups (general and laryngectomized), as well as compared to multiple sclerosis (MS) patients. The COPE response patterns have also been compared to the Beck depression inventory (BDI) scores. Age and gender of patients were not directly associated with choice of coping. Within the problem-focused coping indexes, the coping index “active coping” was reported to be most utilized among HNSCC patients, whereas “coping by suppression” and “coping by social support” were most utilized among MS patients. Emotional-focused coping was most prevalent among HNSCC patients and lowest among the MS patients. Level of avoidance coping was similar between the groups. The coping of the general HNSCC patients differed most from the MS patients. An association was shown between increased coping efforts and lowered mood. In particular, avoidance coping was associated with lowered mood. These associations were stronger among the MS patients than HNSCC patients. Drinking to cope was most prevalent among the laryngectomized group, and was correlated with BDI scores in all groups. Furthermore, adequate coping seems to be to limit avoidance coping and promote coping by acceptance. The response pattern of the COPE inventory seems to be valid among HNSCC and MS patients
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