Mobile Micro-X-ray Fluorescence Analysis (XRF) on Medieval Paintings

X-ray fluorescence has long been applied to objects of art and archaeology for non-destructive elemental analysis. When the object under investigation is either too big or too fragile to be moved a mobile instrument is needed which can be brought on site. A short overview of the development of techniques and applications shall be given in the paper. Then three case studies are reported in which ArtTax/Artax spectrographs were applied for the analysis of medieval paintings. Experimental issues are discussed with respect to the application to paintings as well

Deir el-Médina

La mission a débuté plus tard que prévu, car les autorisations de la Sécurité ont été délivrées fin janvier, deux semaines après la date du 15 janvier fixée pour l’ouverture de la mission. Faute de temps, certaines équipes n’ont pas réussi à atteindre leurs objectifs. La mission a poursuivi les travaux engagés en 2018 axés sur l’étude et la restauration des tombes de la nécropole de l’ouest et du mobilier conservé dans les magasins du site. Quatre équipes sont intervenues dans les TT 2, TT 2B..

Individualised prediction of drug resistance and seizure recurrence after medication withdrawal in people with juvenile myoclonic epilepsy: A systematic review and individual participant data meta-analysis

Summary Background A third of people with juvenile myoclonic epilepsy (JME) are drug-resistant. Three-quarters have a seizure relapse when attempting to withdraw anti-seizure medication (ASM) after achieving seizure-freedom. It is currently impossible to predict who is likely to become drug-resistant and safely withdraw treatment. We aimed to identify predictors of drug resistance and seizure recurrence to allow for individualised prediction of treatment outcomes in people with JME. Methods We performed an individual participant data (IPD) meta-analysis based on a systematic search in EMBASE and PubMed – last updated on March 11, 2021 – including prospective and retrospective observational studies reporting on treatment outcomes of people diagnosed with JME and available seizure outcome data after a minimum one-year follow-up. We invited authors to share standardised IPD to identify predictors of drug resistance using multivariable logistic regression. We excluded pseudo-resistant individuals. A subset who attempted to withdraw ASM was included in a multivariable proportional hazards analysis on seizure recurrence after ASM withdrawal. The study was registered at the Open Science Framework (OSF; https://osf.io/b9zjc/). Findings  368) was predicted by an earlier age at the start of withdrawal, shorter seizure-free interval and more currently used ASMs, resulting in an average internal-external cross-validation concordance-statistic of 0·70 (95%CI 0·68–0·73). Interpretation We were able to predict and validate clinically relevant personalised treatment outcomes for people with JME. Individualised predictions are accessible as nomograms and web-based tools. Funding MING fonds

„Naumburské kolegium“ – Interdisciplinární výzkum v západním chóru dómu v Naumburgu

The Cathedral in Naumburg is an outstanding example of ecclesiastical architecture in Germany. In particular this is due to its statues and reliefs in the west choir created in the middle of the 13th century. This paper gives an overview of the “Naumburg Kolleg”, a three year interdisciplinary research programme funded by the Volkswagen Foundation. Within this project, eleven scientists of six different scientific disciplines (art technology and conservation science, natural sciences, building archaeology, history of art, medieval history/regional history, economic geography, and tourism research) deal with open questions concerning the west choir of Naumburg Cathedral. Working as far as possible on-site provides ideal conditions for research, mutual assistance and exchange of experience among the scientists. This close connection and the resultant interdisciplinary exchange of knowledge render the Naumburg Kolleg an innovative approach to a historic monument. At the same time it offers a unique opportunity to promote junior researchers specialised in the conservation and preservation of cultural assets and cultural development by enabling them to prepare their doctoral theses. The findings and results of the Naumburg Kolleg are not only presented in professional circles and applied in the field of conservation but are also communicated to a wider public. Besides giving an overview of research questions and objectives, this paper particularly mentions results from the research fields of art technology and conservation science, natural sciences, and building archaeology

HPLC–HR-ESI–MS/MS identification of fluorescent dyes and optical brighteners and their degradation products in daylight fluorescent paints

Abstract Daylight fluorescent paints are luminous colors that are increasingly used in contemporary art. The pigments consist of a synthetic resin in which fluorescent dyes and optical brighteners are embedded. In the recent years, several research articles have been published on the composition of daylight fluorescent pigments. Despite the growing research on the aging behavior of daylight fluorescent paints, little is known to date about the chemical processes involved in aging. In the research presented here, we used dialysis to separate the colorants from the resin. HPLC–HR-ESI–MS/MS was used to extend the elucidation of the dye composition. A variety of rhodamines and coumarins, an aminonaphthalimide dye and another optical brightener were determined. NMR was used to elucidate the structure of an additional hemicyanine dye not listed in the Colour Index. Furthermore, reference substances were artificially aged under visible light and UV radiation and the degradation products were analyzed accordingly. N-deethylation, hydroxylation and higher oxidation processes were found to be the main degradation pathways for all colorants. For most dyes and optical brighteners, there was no difference between aging under visible light and aging under UV radiation. When the results were checked on samples of aged paint mock-ups, it was found that only a few of the degradation products can still be detected in the case of very advanced aging even with the smallest sample quantities

Evaluation of the Composition, Thermal and Mechanical Behavior, and Color Changes of Artificially and Naturally Aged Polymers for the Conservation of Stained Glass Windows

Investigations of historical conservation materials on historical stained glass windows of the Naumburg Cathedral in Germany offered an opportunity for the study of polymers, naturally aged in a non-controlled environment. This allowed the conservation history of the cathedral to be traced and expanded by valuable insights. The historical materials were characterized through the use of spectroscopy (FTIR, Raman), thermal analysis, PY-GC/MS, and SEC on taken samples. The analyses show that acrylate resins were predominantly used for conservation. The lamination material from the 1940s is particularly noteworthy. Epoxy resins were also identified in isolated cases. Artificial aging was used to investigate the influence of environmental influences on the properties of the identified materials. Through a multi-stage aging program, influences of UV radiation, high temperatures and high humidity can be considered in isolation. Piaflex F20, Epilox, Paraloid B72 as a modern material and combinations of Paraloid B72/diisobutyl phthalate and PMA/diisobutyl phthalate were investigated. The parameters yellowing, FTIR spectra, Raman spectra, molecular mass and conformation, glass transition temperature, thermal behavior, and adhesive strength on glass were determined. The effects of the environmental parameters on the investigated materials are differentiated. UV and extreme temperatures tend to show a stronger influence than humidity. The comparison of the artificially aged samples with the naturally aged samples from the cathedral shows that the latter were less aged. Recommendations for the conservation of the historical stained glass windows were derived from the results of the investigation

Long term reliability of nociceptive withdrawal reflex thresholds

Background: The nociceptive withdrawal reflex (NWR) is a polysynaptic spinal reflex protecting the body from harmful stimuli. Two different methods to assess its' threshold (NWR-T) have been part of clinical trials concerning the evaluation of the nociceptive system in the human body. NWR-T's are gathered by stimulation at the sole of the foot and over the sural pathway. Consequently, EMG analyzes the muscle activity over the biceps femoris and tibialis anterior muscle. Past studies favor stimulation at the sole of the foot. New method: The two methods were compared concerning retest-reliability and subjective pain ratings. The retest-reliability was tested over a period of 21 days using an up-down staircase method. Reliability was evaluated with a Bland Altman agreement analysis. Subjective pain ratings were evaluated with a numeric rating scale (NRS). Results: NWR T assessment was successful for all subjects. The EMG muscle activity had larger reflex amplitudes for measurements of the tibialis anterior muscle. NWR-T values showed greater variability than NRS values. Comparison with existing method: The retest-reliability over a period of 21 days showed stable NWR-T results for both stimulation sites, but superior reliability was gathered with stimulation at the sole of the foot. Subjects rated stimulation over the sural pathway as more painful. Conclusions: The NWR-T upholds reliable measurements over a longer period of time and seems to be a stable measure for pain condition. Reliability estimations, EMG recordings, and subject's rating show stimulation at the sole of the foot could be the better choice