A TORQUE OF EARLY ROMAN TIME FROM KALINOVO (KALININGRAD REGION, RUSSIA): THE COMPOSITION OF ENAMEL AND DATA ON CHRONOLOGY AND ORIGIN

В статье рассмотрен химический состав и техника нанесения красной эмали гривны, производной от типа Хавор, происходящей из могильника Калиново самбийско-натангийской культуры (Калининградская обл.). Гривна датирована второй половиной I - второй третью II в. н. э. Установлено, что эмаль была изготовлена по «кельтскому» рецепту с высоким содержанием меди и свинца. Однако если состав в данном случае является скорее хронологическим, чем культурноопределяющим признаком, то его сочетание с техникой нанесения эмали (в прорезные углубления-насечки) заставляет искать прототипы данного украшения среди образцов кельтского эмальерного ремесла. Данные о хронологии и технологической традиции, в которой изготовлена гривна, полученные на основании стилистического анализа и состава эмали, хорошо согласуются с результатами комплекса исследований, посвященных данной находке. The article considers the chemical composition and technique of applying the red enamel on the torque derived from the Havor type, originating from the cemetery of Kalinovo of Sambian-Natangian culture (Kaliningrad region). The torque dates back to the second half of I - second third of II c. AD. The enamel was produced using «Celtic» recipe with high copper and lead content. The composition of the enamel in this case is rather chronological than a culturally determining indication. However, its combination with the technique of enamelling (in the slotted recessing notches) gives grounds to search for the prototypes of this decoration among the samples of the Celtic enamel craft. The data on the chronology and technological tradition in which the torque was made, obtained on the basis of stylistic analysis and data on the enamel composition, well agree with the results of a comprehensive studies of this find.

Raman spectroscopy analysis of dental enamel organic and mineral composition: an experimental non-randomised study

Background. Contemporary dental diagnosis should supplement clinical examination with instrumental diagnostic techniques. Raman spectroscopy has become widely adopted due to high spatial resolution, non-invasiveness, the lack of strict requirements and ease of sample preparation.Objectives. A qualitative assessment of enamel mineral and organic composition dynamics using Raman spectroscopy.Methods. Raman spectroscopy was used as primary research method. The trial bench consisted of a Shamrocksr-303i high-resolution digital spectrometer with built-in DV420A-OE cooled optical detector (spectral range 200–1200 nm), RPB-785 optic fibre scattering probe integrated with LuxxMaster LML-785.0RB-04 laser source with wavelength 785 nm.Software spectrum processing was performed with Wolfram Mathematica 9. Spectra were denoised with a median filter (5 points), the approximating line (fifth order polynomial) of autofluorescent component was determined in 700–2200 cm-1 range using an iterative algorithm and then subtracted to receive isolated Raman spectra.Linear discriminant analysis (LDA) of data was performed with the IBM SPSS Statistics package. Results. The assay included 28 teeth, with 14 extracted for orthodontic indications and 14 — for chronic periodontitis. Spectral dental enamel dynamics has been established in periodontal disease and after the in-office bleaching procedure. The evidence obtained can be applicable in dental practice to verify patients at risk of periodontal disease by interpreting the tooth enamel spectral properties, as well as prior to in-office bleaching.Conclusion. We demonstrate high efficiency of Raman spectroscopy for qualitative assessment of the mineral and organic enamel composition dynamics in various settings. Raman spectroscopy is confirmed effective and versatile in various aetiologies. It was successfully applied to diagnose periodontitis by changes in the organic and mineral enamel composition and evaluate enamel after in-office bleaching.

Investigation of the Influence of Technological Regimes of High-Temperature Firing on the Structure and Properties of Silicate-Enamel Coatings for Carbon Steels

The silicate-enamel coating becomes the actual coating as a result of firing, which is a process of heating steel products coated with a “biscuit” dried slip layer, until completely melted, and a continuous coating is obtained on a metal substrate. With the constantly increasing requirements for the technical and operational properties of enameled products in the production of steel pipelines, it is advisable to use single-layer enameling, which saves raw materials and energy, due to the reduction in the number of layers and firing cycles of products. Its use for large-sized products, such as pipelines, eliminates their warping that occurs during repeated firing. In addition, the use of single-layer coatings makes it possible to obtain a better surface of products, since with a decrease in the resulting coating thickness it becomes more elastic and impact-resistant. All of the above is predetermined both by the structure of the glass coating itself and the generally formed steel - enamel composition. Therefore, knowledge of the structure, as well as of the physicochemical processes that occur during the firing of the enameled product, is necessary to solve technological issues successfully.

TWO-COMPONENT COLD CLOISONNE AND CHAMPLEVE ENAMELS: STUDY OF DEFECTS

Types of defects of cold two-component cloisonne and champleve enamels are investigated and systematised. The reasons for the appearance of defects at different stages of enameling jewellery are determined. It is shown that enamel coating defects can occur at any stage of the enamel process. Possible ways to eliminate defects of enamel coating are proposed. Recommendations for the prevention of defects at different stages of cloisonne and champleve enameling are worked out. The most common defects include air bubbles in the enamel and the ingress of foreign contaminants. At initial stages, it is recommended that one observes the technological regulations for metal base and enamel composition preparation. The duration and ease of repair of the defect depends on the detection time of the latter. After the enamel is cured, all defects are irreplaceable.

Crystallographic and Colorimetric Analysis of Dental Enamel

Tooth color and the correlation of the compostion of dental enamel with color were investigated in samples of teeth from two medieval Serb cemeteries. Differences in the composition of apatite crystals in the dental enamel of the two samples were found. Color ranges of teeth from the two samples differ in hues and chromas. This result suggests that enamel composition may have an influence on the color of teeth. The prevalence of chlorapatite in enamel causes tooth color to be closer to red and of higher chroma than teeth whose enamel consists of hydroxylapatite. No evidenc indicated that soil ingredients were incorporated into the dental enamel of either sample.

In vitro Evaluation of Enamel Surface Treated with Fluoride After Bleaching and Etching Erosive Processes

The anti-erosion effect of fluoride on the enamel surface was investigated by ATR-FTIR, SEM and EDX techniques. Four extracted teeth (two incisors and two premolars) were initially bleached with carabamide peroxide and etched with ortho-phosphoric acid then fluoride treatment was applied. Significant differences in enamel composition and morphology were observed providing the effect of fluoride application in remineralization of teeth. Infrared spectroscopy was employed to probe the changes in enamel structure. Scanning electron microscopy/energy dispersive X-ray spectroscopy analysis revealed higher content in F of teeth enamel. Morphology changes revealed a re-mineralization of enamel surface after the treatment with fluoride gel.

Endocranial preservation of a Carboniferous actinopterygian from Lancashire, UK, and the interrelationships of primitive actinopterygians

The gross brain structure of an Upper Carboniferous ( ca . 310 Myr ago) ray–finned fish (Actinopterygii) is described from exceptionally well–preserved fossil material from the Burnley region of Lancashire, UK. Previously identified as ‘ Rhadinichthys ’ planti , the species is reassigned to the genus Mesopoma . Morphological characters derived from these data are combined with reviews of cranial skeletal anatomy, enamel composition, oculomoter muscle insertion and paired fin morphology to test and reanalyse hypotheses of primitive actinopterygian interrelationships. Results indicate that ancestral chondrostean (sturgeon and paddlefish) and neopterygian (teleost, amiid and gar) lineages diverged earlier than current theories suggest. Palaeonisciformes, a taxonomic group widely used to include most Palaeozoic actinopterygians, include a significant number of primitive neopterygians, several of which may form a distinct monophyletic clade. Within this revised phylogenetic context, changes in gross brain morphology from primitive conditions, as revealed by fossil data, highlight likely specializations in extant non–teleostean actinopterygians.