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Schadstoffe beschäftigen derzeit Museen weltweit Heute weiß man, dass diese auch aus Materialien, die für den Ausstellungsbau verwendet werden, austreten können, was eine Gefahr für Exponate darstellt. Ein neues Verfahren namens BEMMA bietet nun erstmalig die Möglichkeit, relativ schnell und effektiv eine problemorientierte Untersuchung und Bewertung mit belastbaren und reproduzierbaren Ergebnissen vorzunehmen.
Formic and acetic acids are often responsible for damage of cultural objects, e. g. glass and metal corrosion or changing and fading of colours. Museums all around the world are equipped with different show cases. Display cases should protect cultural objects from dust as well as from mechanical damage. Several construction materials which are used for display cases, including wood, glue and coatings, are possible sources of very volatile organic compounds (VVOCs), volatile organic compounds (VOCs) and semi volatile organic compounds (SVOCs). These construction products can emit formic and acetic acids into the indoor or display case air. Modern display cases with small air change rates can cause higher concentrations of formic and acetic acids if any source is installed in the display case (Salthammer and Uhde, 2009). To minimize the risk of damage emissions from building products must be quantified. There is a need for a method for identification and quantification of acetic and formic acid. Some possibilities for the identification of acetic acid exist. The quantification of acetic acid for example after sampling on TENAX® or CARBOTRAP and thermal desorption-GC in accordance with ISO 16000-6 and ISO 16017-1 results in very low recovery rates. A new method should be stabile, robust, reproducible and comparable, with an easy local sampling and determination in laboratories. Miniaturised emission test chambers and model display cases were used to study the recovery rates.
Several construction and building materials, including wood, glue and coatings, are possible sources of very volatile organic compounds (VVOCs) and volatile organic compounds (VOCs) like formic and acetic acid. Due to very high air tightness and very low air exchange rates in new buildings concentrations of these harmful substances can increase considerably. To minimize the risk, emissions from building products should be identified and quantified. With the common standard method, this means Tenax® sampling followed by thermal desorption and GC-MS analysis, these acids could not be detected sufficiently. The aim oft this study is the comparison of two different methods for the determination of acetic and formic acid. The sampling of method one, which is usually used for identification and quantification of VOCs, is done in accordance with ISO 16000-6 and ISO 16017-1 on Carbotrap® 202 multi-bed thermal desorption tube by subsequent identification and quantification with GC-MS. Method two is based on sampling on 2,4-dinitrophenylhydrazine (DNPH) cartridges, derivatisation, elution, identification and quantification of the derivatives with LC-MS/MS (liquid chromatography mass spectrometry/mass spectrometry).
Ausstellungskuratoren, Restauratoren oder Fachplaner stehen immer wieder vor der Entscheidung, geeignete Materialien für Museumsausstattungen auswählen zu müssen. Vitrinen, Depoteinrichtungen, aber auch Transportverpackungen für Kunst- und Kulturgut sollten unbedingt frei von Schadstoffen sein. Ein neues Verfahren ermöglicht nun eine problemorientierte Untersuchung und Bewertung von Materialien mit belastbaren und reproduzierbaren Ergebnissen.
Unterschiedliche Befeuchtungssysteme für Vitrinen, die die Ausstellungsobjekte bei definierter Luftfeuchtigkeit vor externen Einflüssen wie Staub bewahren sollen, wurden im Hinblick auf die Möglichkeit der potenziellen mikrobiologischen Kontamination untersucht. Ergänzend hierzu wurden Parameter wie pH-Wert und Leitfähigkeit des Wassers im Befeuchter untersucht und die mikrobiellen flüchtigen organischen Verbindungen (MVOC, microbial volatile organic compounds) in der Modellvitrine bestimmt. Die Leitfähigkeitsmessung kann als Indikator für den Verunreinigungsgrad des Wassers dienen, weil sie mit der mikrobiologischen Belastung korreliert. Weiterhin war eine mikrobiologische Belastung der Luft in der Modellvitrine auch bei relativ hoher Verunreinigung des Befeuchtungswassers nicht nachzuweisen.
Ionizing radiation damage to DNA plays a fundamental role in cancer therapy. X-ray photoelectron-spectroscopy (XPS) allows simultaneous irradiation and damage monitoring. Although water radiolysis is essential for radiation damage, all previous XPS studies were performed in vacuum. Here we present near-ambient-pressure XPS xperiments to directly measure DNA damage under water atmosphere. They permit in-situ monitoring of the effects of radicals on fully hydrated double-stranded DNA. The results allow us to distinguish direct damage, by photons and secondary low-energy electrons (LEE), from damage by hydroxyl radicals or hydration induced modifications of damage pathways. The exposure of dry DNA to x-rays leads to strand-breaks at the sugar-phosphate backbone, while deoxyribose and nucleobases are less affected. In contrast, a strong increase of DNA damage is observed in water, where OH-radicals are produced. In consequence, base damage and base release become predominant, even though the number of strand-breaks increases further.
Dose enhancement by gold nanoparticles (AuNP) increases the biological effectiveness of Radiation damage in biomolecules and tissue. To apply them effectively during cancer therapy their influence on the locally delivered dose has to be determined. Hereby, the AuNP locations strongly influence the energy deposit in the nucleus, mitochondria, membrane and the cytosol of the targeted cells. To estimate these effects, particle scattering simulations are applied. In general, different approaches for modeling the AuNP and their distribution within the cell are possible. In this work, two newly developed continuous and discrete-geometric models for simulations of AuNP in cells are presented.
These models are applicable to simulations of internal emitters and external radiation sources. Most of the current studies on AuNP focus on external beam therapy. In contrast, we apply the presented models in Monte-Carlo particle scattering simulations to characterize the energy deposit in cell organelles by radioactive 198AuNP. They emit beta and gamma rays and are therefore considered for applications with solid tumors. Differences in local dose enhancement between randomly distributed and nucleus targeted nanoparticles are compared. Hereby nucleus targeted nanoparticels showed a strong local dose enhancement in the radio sensitive nucleus. These results are the foundation for future experimental work which aims to obtain a mechanistic understanding of cell death induced by radioactive 198Au.
Nicht zuletzt bedingt durch den Pferdefleischskandal im Jahr 2013 wurden in Deutschland die Aktivitäten bei der Methodenstandardisierung im Bereich der Tierarten-Differenzierung in den vergangenen Jahren intensiviert. Wenn auch positive Befunde bei dem Nachweis von Bestandteilen aus Pferd in Lebensmitteln wie Lasagne derzeit so gut wie nicht mehr anzutreffen sind, so hat die Tierartendifferenzierung insgesamt beim Nachweis von Verfälschungen in Lebensmitteln einen hohen Stellenwert.
Diese Arbeit fasst daher den aktuellen Stand der Analytik in Deutschland mit Schwerpunkt bei der Standardisierung zusammen. Sie wurde erstellt durch die Arbeitsgruppe „Biochemische und molekularbiologische Analytik“ der Lebensmittelchemischen Gesellschaft mit Unterstützung von Experten der Arbeitsgruppe „Molekularbiologische Methoden zur Pflanzen- und Tierartendifferenzierung“ (§ 64 LFGB) sowie der ALTS-Arbeitsgruppe „Immunologie und Molekularbiologie“ (jeweils D).
Work on standardising methods in the field of animal species differentiation has been intensified in Germany in recent years, not least due to the horsemeat scandal in 2013. Even though there are now hardly ever any positive findings any more in examinations to detect horse adulterations in foods such as lasagne, animal species differentiation altogether ranks high in detecting adulteration of foods. This article therefore summarises the current status of analytical techniques used in Germany with standardisation at German level. It has been established by the working group “Biochemical and Molecular Biological Analytics” of the Lebensmittelchemische Gesellschaft (Food Chemistry Society within the German Chemical Society) with support of experts in the working group “Molecular biology techniques for differentiating plant and animal species” (§ 64 of the German Food and Feed Code – LFGB) and the “Immunology and molecular biology” task force of the food hygiene and Food of animal origin working group (ALTS), both from Germany.