It's Only a Part of the Story: Analytical Investigation of the Inks and Dyes Used in the Privilegium Maius.

The Privilegium maius is one of the most famous and spectacular forgeries in medieval Europe. It is a set of charters made in the 14th century upon commitment by Duke Rudolf IV, a member of the Habsburg family, to elevate the rank and the prestige of his family. These five charters, now kept at the Österreichisches Staatsarchiv in Vienna, have been subjected to a thorough interdisciplinary study in order to shed light on its controversial story. The charters are composed of pergamenaceous documents bound to wax seals with coloured textile threads. The present contribution concerns the characterisation of the inks used for writing and of the dyes used to colour to the threads: Are they compatible with the presumed age of the charters? Though showing only a part of the whole story of the charters, dyes analysis could contribute in assessing their complex history from manufacturing to nowadays. The dyes were characterised with non-invasive in situ measurements by means of fibre optic (FORS) and with micro-invasive measurements by means of Surface Enhanced Raman Spectroscopy (SERS) and High-Performance Liquid Chromatography with Mass Spectrometry (HPLC-MS) analysis. The results showed that the threads of four of the charters (three dyed with madder, one with orchil) were apparently coloured at different dyeing stages, then re-dyed in the 19-20th century.

Differential Ultra-Wideband Microwave Imaging: Principle Application Challenges.

Wideband microwave imaging is of interest wherever optical opaque scenarios need to be analyzed, as these waves can penetrate biological tissues, many building materials, or industrial materials. One of the challenges of microwave imaging is the computation of the image from the measurement data because of the need to solve extensive inverse scattering problems due to the sometimes complicated wave propagation. The inversion problem simplifies if only spatially limited objects—point objects, in the simplest case—with temporally variable scattering properties are of interest. Differential imaging uses this time variance by observing the scenario under test over a certain time interval. Such problems exist in medical diagnostics, in the search for surviving earthquake victims, monitoring of the vitality of persons, detection of wood pests, control of industrial processes, and much more. This paper gives an overview of imaging methods for point-like targets and discusses the impact of target variations onto the radar data. Because the target variations are very weak in many applications, a major issue of differential imaging concerns the suppression of random effects by appropriate data processing and concepts of radar hardware. The paper introduces related methods and approaches, and some applications illustrate their performance.

In vitro measurements of flow using multislice computed tomography (MSCT).

To examine in vitro whether an assessment of flow in normal and obstructed vessels is essentially possible using modern multislice CT-scanners. An experimental model allowed known stenoses to be perfused at defined flow rates. Aorta and coronary arteries were simulated by silicone tubes. A pulsatile pump was used to perfuse water through the system with intermittent injection of a bolus of radio-opaque contrast agent. CT-measurements were carried out with slice orientation perpendicular to the tubes. 50-90% concentric stenoses were examined 5 times at 4 different stenosis slice distances. A mathematical algorithm calculated the temporal density changes within a ROI in the tube cross-sections. Quantitative assessment of the data simultaneously acquired with the 16-slice system for the "coronary" and "aortal" time-density curves showed that the model allowed for exclusion of a ≥ 80% stenosis grade with a 99% probability when the slopes of the density increase quotient was > 0.79; a stenosis grade of ≥ 90% could be excluded when the slopes of the density increase quotient was > 0.52. A Quotient > 0.94 for "peak density" was associated with a 99% probability of a stenosis grade ≥ 70%. The 64-slice system allowed stenosis grades of ≥ 80% to be discriminated from lower grades. The general feasibility of the in vitro approach was verified in an in vivo model. The spatial, contrast and temporal resolution of CT scanners with at least 16 detector rows enables qualitative and semiquantitative assessment of stenotic changes in flow.

Measuring the attenuation characteristics of biological tissues enabling for low power in vivo RF transmission.

In clinical routine there is a need of periodical recording of vital parameters in high risk groups, for example the intraocular pressure. A solution for this could be an intracorporeal sensor using a wireless radio frequency (RF) transmitter. Thereby the risk of an infection is reduced, because a percutaneous connection is not necessary. A limiting factor for some organs is the size of implants. For designing an energy efficient low power RF transmitter, the dielectric parameters of representative biological tissues have to be determined. In this article two methods of measurement are presented, the coaxial probe and transmission line method. With this information about the dielectric parameters a miniaturized RF transmitter was built for proofing tests on phantoms with equal properties like biological tissue.