Radiocarbon Dates from Late Neolithic and Early Bronze Age Settlements at Hemmed, Højgård and Trappendal, Jutland, Denmark

Radiocarbon Dates from Late Neolithic and Early Bronze Age Settlements at Hemmed, Højgård and Trappendal, Jutland, Denmar

Radiocarbon datings at Ringkloster

Radiocarbon datings at Ringkloste

The Effects of Possible Contamination on the Radiocarbon Dating of the Dead Sea Scrolls II: Empirical Methods to Remove Castor Oil and Suggestions for Redating

While kept at the Rockefeller Museum in East Jerusalem, many Dead Sea Scroll fragments were exposed to castor oil by the original team of editors in the course of cleaning the parchments. Castor oil must be regarded as a serious contaminant in relation to radiocarbon dating. If modern castor oil is present and is not removed prior to dating, the 14C dates will be skewed artificially towards modern values. Earlier, it was shown that the standard AAA pretreatment procedure used in the 2 previous studies dating Dead Sea Scroll samples is not capable of removing castor oil from parchment samples. In the present work, we show that it is unlikely that castor oil reacts with the amino acids of the parchment proteins, a finding which leaves open the possibility of devising a cleaning method that can effectively remove castor oil. We then present 3 different pretreatment protocols designed to effectively remove castor oil from parchment samples. These involve 3 different cleaning techniques: extraction with supercritical CO2, ultrasound cleaning, and Soxhlet extraction—each with their own advantages and disadvantages. Our data show that the protocol involving Soxhlet extraction is the best suited for the purpose of decontaminating the Dead Sea Scrolls, and we recommend that this protocol be used in further attempts to 14C date the Dead Sea Scrolls. If such an attempt is decided on by the proper authorities, we propose a list of Scroll texts, which we suggest be redated in order to validate the 14C dates done earlier.

Naturvidenskabelige undersøgelser af mursten i Sorø Klosterkirke – sortering af mursten

Faculty surveys of bricks in Sorø Abbey – sorting of bricksBy Kaare Lund Rasmussen, Christina Andersenand Thomas BertelsenSmall samples have been procured with hammer and chisel from the bricks in the crowns of the walls in the medieval church of the Cistercian monastery of Sorø, Denmark. The samples have been subjected to three types of analyses: magnetic susceptibility, thermoluminescence sensitivity, and for the first time colour measurements. The colour measurements were performed with a handheld Minolta CM-2600d photo spectrometer yielding very precise colours in the 1976 CIE colour system (L*,a*,b*). Extensive sorting of bricks according to colour seems to have been a common feature in the vast group of Danish late medieval building projects where the varying colours of bricks were used as decoration. Genuine patterns seem to be a phenomenon of eastern Denmark with Roskilde Cathedral’s Chapel of the Three Kings from about 1460 as the noblest representative (fig. 13). Masonry with belts of bricks of contrasting colours also occurs, while arches of alternating red and dark bricks appear across the country (fig. 14). The most common type of decoration, however, was red façades with evenly spread dark bricks. This might seem coincidental but the absence of this feature in the interior walls underlines its role as a deliberate facade décor. Possibly, bricks were also sorted by colour when the building of the Abbey Church of Sorø was commenced shortly after the founding of the abbey in 1161. Only small parts of the original façade of the church have been preserved, for example the gable of the northern transept, which is a well-balanced blend of red and dark bricks (see fig. 15, p. 118). In contrast, the interior walls above the vaulting are built of much more monochrome bricks, which points to a deliberate wish for polychrome façades

Insulin gene regulation and islet development as studied in genetically modified tumors and transgenic laboratory animals

The pancreatic islet of Langerhans is composed of four highly distinct cell types specialized to mass produce a particular hormone. Insulin is thus the main product released from the islet B—cell in response to elevated glucose.The four cell types maturate during fetal development. Pluripotent rat islet tumors can to a certain degree undergo similar maturation processes when passaged in vivo. Such a model has been used to study the B—cell specific process of insulin gene activation. Transgenic mice have been instrumental in defining the functional regulatory elements involved in restricting the insulin gene activity to the pancreatic B-cell. The tissue-specific enhancer/promoter has thus been identified and used in combination with a series of other genes which in transgenic mice targets expression of the gene in question selectively to the B-cell. Important transacting factors have been identified and cloned which are in part responsible for mediating tissue specific insulin gene expression. One such factor when "knocked-out" results in a phenotype lacking the entire pancreas. Future developments in targeting "knockout" of genes to particular cell types will help dissecting out the multiple functions of such regulatory transacting factors