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Abstracts Tóth Attila Lajos Electron Probe Microanalysis For Restorers. Part Iii: Sampling, Sample Preparation, Data Processing and Presentation No analytical measurement can be better and more reliable than the preceding sampling and sample preparation. Even the best instrument in the hand of the most skilled analyst gives poor results from sample of inferior quality and uncertain origin. In the practice of archaeometry and restoration the situation is even more problematic, as the sampling and preparation is done by the archaeologist or the restorer (i.e. the specialist) in most of the cases on the site or in the museum, while the measurement by the analyst. What is even more dangerous, the modem instruments practically always give an output, what - in most of the cases - seems to be reliable (computer printout of corrected X-ray intensities with averages, standard deviations, furthermore images, line scans and element mapping can be extremely convincing). These results — if the analyst is professional - surely characterize the analyzed microvolume or the whole of the sample in the microscope, but the obvious requirement is the characterization of the piece of art. Our goal is to ensure the reliability of the whole process, from the sampling to the data correction and presentation. The paper shortly summarize the rules of sampling and sample preparation in the electron microprobe analysis, the importance of documentation and the presence of the restorer during the measurement, Attila L. Tóth PhD, CSc Senior res.fellow Hungarian Academy of Scienses MFA H-1121 Budapest Konkoly-Thege u 29-33. Phone: +36-1-392-2691; +36-30-287-5290 E-mail: tothal@mfa.kfki.hu Gyöngyvér Mara - Zsuzsanna Mara Fungi Damaging Works of Art; Their Detrimental Effects The author discusses damages caused by mould fungi on works of art made from organic materials, as well as their examination methods. As for its taxonomy, the fungus kingdom is highly varied; several genera are known of species which cause damage to works of art, such as Altemaria, Aspergillus, Cladosporium, Myrothecium, Paecylomices and Penicillium. Invasion by fungal hyphae causes serious physical degradation in objects; even their material may crumble away. Deterioration can also be chemical in nature; exoenzymes or organic and inorganic acids produced by fungi may damage structural elements of works of art. Not infrequently, fungal hyphae penetrate and discolour materials without extracting nutrients from them. Papers may display coloured deformation called foxing. Beyond material degradation, fungi may also frequently cause health impairment through the spores, mycotoxins and volatile organic compounds (VOC) they produce. Mould fungi are examined predominantly by classical microbiological methods. Samples taken from the surface of works of art are cultivated on Czapek-Dox agar in sterile conditions for about five days of incubation at a temperature of 30°C. Fungal growths are then analysed both morphologically and microscopically. With the appearance of electron microscopy, scanning electron microscopy (SEM) is used to detect fungal colonisation and mechanical deterioration in works of art. Owing to the development in molecular biological methods, several DNA based methods are available for the identification of fungal species that cause deterioration or are difficult to cultivate. First and foremost step in up-to-date conservation of works of art is preventative protection which calls for appropriate storage conditions at low temperature and below 60 per cent relative humidity. As long as stored or displayed in the specified conditions, danger of microbiological contamination of objects of art is eliminated. Protection against fungi can also be ensured by physical (radiation, temperature) and chemical fumigation methods. Reducing temperature, such as freezing, proves ineffective for fungi; on the contrary, increased temperature may prove an effective method for protection against fungi, provided that objects of art are treated at a suitably high temperature and for an appropriate time. Another physical method is radiation treatment; y radiation is used for the treatment of paper and wood based objects. While a small dose of y radiation is highly effective against vermin, the suitable dosage against some fungi is 10-16 kilo grey. Of inert gaseous disinfectants, N2 is unsuitable for the elimination of fungi by fumigation. An environment with low 02 content (0.005-0.1 per cent) however, might effectively eliminate aerobe cellulose-destroying micro-organisms. If newly acquired from an alien environment, a thorough examination of the item is imperative. If signs of moulding are observed in the course of macro- and microscopic examinations, it is important to cultivate the fungi for the purpose of identification. In this way, information can be obtained on the degrada187
