'To keep the colours fresh, alive and bright': the influence of preparatory layers on the durability of oil painting, according to North West European recipe books 1550–1900

Preparatory layers (size and ground) exert an important influence on the durability of a painting. This has been proved through technical studies of paintings, but is also evident from the continued attention in historical recipes to the effects of preparatory layers on paint stability. This paper explores the types of degradation described in preparatory layer recipes, their causes, and solutions offered by historical authors to prevent degradation from occurring. A survey of some 650 recipes for preparatory layers from North West European sources 1550–1900 demonstrates that choices made during the creation of a painting were not only guided by immediate results, but also that artists anticipated the long-term effects of these choices. Not only did historical authors discuss the impact of choice of ground materials, layer build-up, structure and ground colour on a painting’s stability, but artists were also warned that even the quality or thickness of layers as unobtrusive as a size or isolation layer could influence a painting’s longevity. Some authors also included advice to prevent degradation from occurring. Historical authors focused mainly on two types of degradation: delamination and discoloration. Ground thickness and the age of the ground before paint application were considered influential. The fact that advice to improve the stability of the ground is found into the last decades of the 19th century reveals the continued search for better support preparation; a flawless preparatory system had not been found, notwithstanding innovations introduced during the period and claims on the success of improvements that often accompanied ‘new’ ground formulations

Uric acid as a novel biomarker for bone-marrow function and incipient hematopoietic reconstitution after aplasia in patients with hematologic malignancies.

Prolonged aplasia and graft failure (GF) represent life-threatening complications after hematopoietic cell transplantation (HCT) requiring suitable biomarkers for early detection and differentiation between GF and poor graft function (PGF). Uric acid (UA) is a strong immunological danger signal. Laboratory results were analyzed from patients undergoing either allogeneic or autologous HCT or induction chemotherapy for acute leukemia (n = 50 per group, n = 150 total). During therapy, UA levels declined from normal values to hypouricemic values (all p < 0.001). Alongside hematopoietic recovery, UA serum levels returned to baseline values. During aplasia, UA levels remained low and started steadily increasing (defined as > two consecutive days, median one 2-day increase) at a median of 1 day before rising leukocytes in allogeneic HCT (p = 0.01) and together with leukocytes in autologous HCT (median one 2-day increase). During induction chemotherapy, a UA increase was also observed alongside rising leukocytes/neutrophils but also several times during aplasia (median 3 increases). Most HCT patients had no detectable leukocytes during aplasia, while some leukocytes remained detectable after induction therapy. No increase in UA levels was observed without concomitant or subsequent rise of leukocytes. Changes in UA serum levels can indicate incipient or remaining immunological activity after HCT or induction therapy. They may, therefore, help to differentiate between PGF and GF