Obtaining Cross-Sections of Paint Layers in Cultural Artifacts Using Femtosecond Pulsed Lasers

Recently, ultrafast lasers exhibiting high peak powers and extremely short pulse durations have created a new paradigm in materials processing. The precision and minimal thermal damage provided by ultrafast lasers in the machining of metals and dielectrics also suggests a novel application in obtaining precise cross-sections of fragile, combustible paint layers in artwork and cultural heritage property. Cross-sections of paint and other decorative layers on artwork provide critical information into its history and authenticity. However, the current methodology which uses a scalpel to obtain a cross-section can cause further damage, including crumbling, delamination, and paint compression. Here, we demonstrate the ability to make controlled cross-sections of paint layers with a femtosecond pulsed laser, with minimal damage to the surrounding artwork. The femtosecond laser cutting overcomes challenges such as fragile paint disintegrating under scalpel pressure, or oxidation by the continuous-wave (CW) laser. Variations in laser power and translational speed of the laser while cutting exhibit different benefits for cross-section sampling. The use of femtosecond lasers in studying artwork also presents new possibilities in analyzing, sampling, and cleaning of artwork with minimal destructive effects.

Where science meets art

Scientific methods inform conservation efforts in the quest to preserve cultural heritage

[Collaborative care for co-morbid major depressive disorder in chronically ill outpatients in a general hospital]

BACKGROUND

Depression is highly prevalent in patients with chronic physical illnesses. A promising intervention for this group of patients is the collaborative care treatment as developed in the us.

AIM

To demonstrate the prevalence of depression and the risk factors of depression in diabetes patients, to describe how the screening for depression can be carried out and to assess whether the collaborative care treatment in the Netherlands is effective.

METHOD

A questionnaire was completed every three months in order to determine whether there was an improvement in patients' depression and physical symptoms. The outcomes were analysed by means of the multilevel logistic regression analyses.

RESULTS

On the basis of the Patient Health Questionnaire, about 26% of the diabetes patients were found to have a depression. This questionnaire was validated for the measurement of depression in diabetes patients, the best results being found at a cut-off point of 12. In cases of fairly severe depression, collaborative care had no effect on depressive symptoms but did reduce severe physical complications. In cases of more severe depression, collaborative care only had an effect on depressive symptoms, but was not found to have any effect on physical complications.

CONCLUSION

There is evidence that collaborative care can reduce depression and physical complications in chronically ill patients. However, more research is needed to find out whether collaborative care can become more effective if it is supplemented with digital methods and group therapy.

Mid-infrared fiber-optic reflection spectroscopy (FORS) analysis of artists' alkyd paints on different supports

Mid-infrared Fourier transform fiber-optic reflection spectroscopy (mid-IR FORS) is a noninvasive and flexible spectroscopic technique. It is ideal in the art conservation field because of its portability for on-site and in situ analysis of art objects, analyses that require delicate handling, or analyses of objects that cannot be sampled. This paper studies the applicability of mid-IR FORS for the characterization of commercial artists' alkyd paints cast on different supports. As predicted, the quality of the spectra and intensity of characteristic peaks varied according to reflectivity, roughness, and materials used in the supports. The presence of organic binder was best identified by its carbonyl peak (the most intense) and CH(2) stretching peaks; however, this was not sufficient to distinguish between oil and alkyd binders. The differentiation and identification of alkyds and oils must rely on the unique fingerprint peaks. However, in some cases, the fingerprint peaks were difficult to interpret because of strong absorptions caused by inorganic paint fillers, often present in modern paint formulations, resulting in anomalous dispersion and reststrahlen distortions.

A sensitive and practical fluorimetric test for CNT acidic site determination

A sensitive and practical colorimetric test for oxidized carbon nanotubes (CNTs) is described. The assay is based on direct labeling with the commercially available fluorescent dye thionin acetate (THA). This strategy offers the possibility for quantitation of acidic sites in a very fast and easy way.