Colour Transformation and Textural Change in Biotite: Some Remarks for the Interpretation of Firing Technology in Greyware Pottery Thin-Sections

Firing is a crucial step in the production of pottery, as it irreversibly transforms the clay into ceramic. Clay sintering and subsequent vitrification occur during firing, together with other transformations undergone by specific minerals and rock inclusions according to their optical and physical properties, including their colour. Some of these are visible in thin-sections and might be interpreted as technological markers or contribute to the estimation of firing temperatures, although most of them are poorly documented. In this paper, we approach the transformations in colour, texture and optical properties that occurred in biotite inclusions from medieval greyware pottery. Our study considers a batch of 40 pottery samples from medieval Catalonia analysed by XRD. According to the estimated firing temperature ranges and atmospheres, we examined the behaviour of biotite at different temperature ranges from 700 °C to 1000 °C by means of optical microscopy, considering its size, shape and abundance, and compared these features to a wider assemblage of thin-sections from medieval earthenware. The results obtained are interesting, as they offer a valuable reference for petrographic studies on pottery. We discuss the potential of ceramic petrography as a way to perform more precise and refined sample selection for further analysis on archaeothermometry.

Treatment of Surgical Scars: A Pilot Study Comparing Fractional Photothermolysis with Pulsed Dye Laser

Introduction: Fractionated resurfacing has been demonstrated in case reports to notably improve the cosmetic outcome of surgical scars. The aim of this study was to compare fractionated resurfacing (fractional photothermolysis [FP]) with the pulsed dye laser (PDL). If novel minimally invasive therapies such as FP are proven to be safe and effective for the treatment of surgical scars, patients receiving cutaneous surgery will be significantly allayed in their concern about the cosmetic outcomes of their surgical scars. Materials and Methods: Randomized, double-blinded split scar study in 15 scars in a total of 12 patients after Mohs surgery for nonmelanoma skin cancer on the face, neck, chest, or back. Patients were treated on one-half of the scar with 1550-nm erbium doped fiber laser and on the contralateral half with the 595 nm V-Beam PDL. Patients were treated with each laser device on half of the scar for a total of 2 treatment sessions at 2-week intervals. Results: After a series of 2 treatments, greater improvements were noted in the portion of surgical scars treated with FP than with PDL in overall cosmetic outcome (FP, mean improvement = 59.7%, range = 40–80% vs PDL, mean improvement = 47.9%, range = 20–60%; P= .05). In pigmentary variation (FP, mean improvement = 47.2%, range = 20–80% vs PDL, mean improvement = 28.5%, range = 0–40%; P<.05); scar thickness (FP, mean improvement = 71.4%, range = 40–80% vs PDL, mean improvement = 35.4%, range = 0–60%; P<.05); and scar texture (FP, mean improvement = 64.3%, range = 40–80% vs PDL, mean improvement = 43.4%, range = 20–60%; P< .05). A total of 4 scars with significant hypopigmentation had improvements in pigmentation after treatment with FP (mean improvement = 45.0%, range = 20–80%) with no improvement after treatment with PDL (0%) (P < .05). There was no incidence of dyspigmentation, ulceration, or scarring with either device. Conclusions: To the authors' knowledge, this is the first study to compare the outcome of treatment with PDL with FP in terms of pigmentary variation, textural change, and overall cosmetic improvement. The data presented herein suggest that FP results in significantly greater improvements in surface pigmentation, textural variation, and scar thickness relative to PDL. Similar to previous case reports, FP was uniquely successful in improving hypopigmented scars. The greater depth of penetration and significant skin remodeling induced with FP likely account for its greater improvement in textural change and thickness of surgical scars. Both FP and PDL appear to be highly safe modalities for the treatment of surgical scars with minimal discomfort and no adverse effects.