X-ray absorption-based imaging and its limitations in the differentiation of ancient mummified tissue

Objectives: Differentiation of ancient tissues is of key importance in the study of paleopathology and in the evolution of human diseases. Currently, the number of imaging facilities for the non-destructive discrimination of dehydrated tissue is limited, and little is known about the role that emerging imaging technologies may play in this field. Therefore, this study investigated the feasibility and quality of dual-energy computed tomography (DECT) for the discrimination of dry and brittle soft tissue. Moreover, this study explored the relationship between morphological changes and image contrast in ancient tissue by using X-ray micro-tomography (micro-CT). Materials and Methods: An Egyptian mummy head and neck was scanned with DECT at tube voltage/current of 140kVp/27mAs (tube A) and 100kVp/120mAs (tube B). The CT attenuation was determined by regions of interest (ROI) measurements of hard and soft tissue of the mummy skull. Finally, two samples from the posterior neck were dissected to acquire micro-CT images of shrunken dehydrated tissue. Results: Dual-energy CT images demonstrated the high contrast resolution of surface structures from mummy skull. Bone density changes in the posterior skull base as well as soft-tissue alterations of the eyes and tongue were assessed. Micro-CT scans allowed the identification of morphological changes and the discrimination of muscle tissue from inorganic material in samples taken from the neck. Conclusions: Significant attenuation differences (p < 0.0007) were observed within 12 of the 15 ancient tissue groups and organic materials using DECT. We detected a correlation between X-ray scattering and image contrast reduction in dehydrated tissue with micro-CT imagin

Design and evaluation of a low-cost instrumented glove for hand function assessment

BACKGROUND: The evaluation of hand function impairment following a neurological disorder (stroke and cervical spinal cord injury) requires sensitive, reliable and clinically meaningful assessment tools. Clinical performance measures of hand function mainly focus on the accomplishment of activities of daily living (ADL), typically rather complex tasks assessed by a gross ordinal rating; while the motor performance (i.e. kinematics) is less detailed. The goal of this study was to develop a low-cost instrumented glove to capture details in grasping, feasible for the assessment of hand function in clinical practice and rehabilitation settings. METHODS: Different sensor types were tested for output signal stability over time by measuring the signal drift of their step responses. A system that converted sensor output voltages into angles based on pre-measured curves was implemented. Furthermore, the voltage supply of each sensor signal conditioning circuit was increased to enhance the sensor resolution. The repeatability of finger bending trajectories, recorded during the performance of three ADL-based tasks, was established using the intraclass correlation coefficient (ICC). Moreover, the accuracy of the glove was evaluated by determining the agreement between angles measured with the embedded sensors and angles measured by traditional goniometry. In addition, the feasibility of the glove was tested in four patients with a pathological hand function caused by a cervical spinal cord injury (cSCI). RESULTS: A sensor type that displayed a stable output signal over time was identified, and a high sensor resolution of 0.5° was obtained. The evaluation of the glove's reliability yielded high ICC values (0.84 to 0.92) with an accuracy error of about ± 5°. Feasibility testing revealed that the glove was sensitive to distinguish different levels of hand function impairment in cSCI patients. CONCLUSIONS: The device satisfied the desired system requirements in terms of low cost, stable sensor signal over time, full finger-flexion range of motion tracking and capability to monitor all three joints of one finger. The developed rapid calibration system for easy use (high feasibility) and excellent psychometric properties (i.e. reliability and validity) qualify the device for the assessment of hand function in clinical practice and rehabilitation settings

Quantifizierung des Stickstoffs in Wurzeln und Wurzelausscheidungen von Soja

The below ground N allocation of organic soybean was examined in two experiments conducted in Eastern Austria. During early development, individual soybean plants were labelled with a 15N-enriched urea solution by the petiole-feeding method. The 15N enrichment of these plants and surrounding soil relative to their natural 15N abundance was determined at plant maturity. The proportion of soil N derived from roots was calculated from root and soil N isotope data. Total below ground plant N, including rhizodeposits, amounted to between 6 to 48 % of total plant N. The proportion of total plant N allocated below ground was inversely related to shoot N content

Suitability of drought tolerance indices for selecting alfalfa (Medicago sativa L.) genotypes under organic farming in Austria

In eastern Austria, alfalfa is usually grown as a rainfed crop in crop rotations in organic farming systems, where year-to-year rainfall fluctuations cause different levels of drought stress. To identify the suitability of different alfalfa genotypes and drought tolerance indices, 18 contrasting alfalfa genotypes were evaluated under irrigated and rainfed conditions at the research station of the University of Natural Resources and Life Sciences (BOKU), Vienna, Austria, during 2006-08. The first study year (2006) was considered as the establishment year. Five drought tolerance selection indices were estimated based on shoot dry matter, total biomass yield and biological nitrogen fixation (BNF) data. The correlation between irrigated and rainfed performances increased (from r=-0.17 to 0.56) with decreasing stress intensity from the first to the second year. Genotypes Sitel, Plato ZS, Vlasta and NS-Banat were the best genotypes based on their performance under both conditions. Drought tolerance selection indices TOL and SSI showed high correlations (r = 0.32 to 0.81) only with rainfed performance, and SSI was the index that best identified genotypes with high yield potential under rainfed conditions. Indices STI and GMP were the ones that best identified genotypes with high performance under both conditions

Direct action of radiation on mummified cells: modeling of computed tomography by Monte Carlo algorithms

X-ray imaging is a nondestructive and preferred method in paleopathology to reconstruct the history of ancient diseases. Sophisticated imaging technologies such as computed tomography (CT) have become common for the investigation of skeletal disorders in human remains. Researchers have investigated the impact of ionizing radiation on living cells, but never on ancient cells in dry tissue. The effects of CT exposure on ancient cells have not been examined in the past and may be important for subsequent genetic analysis. To remedy this shortcoming, we developed different Monte Carlo models to simulate X-ray irradiation on ancient cells. Effects of mummification were considered by using two sizes of cells and three different phantom tissues, which enclosed the investigated cell cluster. This cluster was positioned at the isocenter of a CT scanner model, where the cell hit probabilities P(0,1, , n) were calculated according to the Poisson distribution. To study the impact of the dominant physics process, CT scans for X-ray spectra of 80 and 120 kVp were simulated. Comparison between normal and dry tissue phantoms revealed that the probability of unaffected cells increased by 21% following cell shrinkage for 80 kVp, while for 120 kVp, a further increase of unaffected cells of 23% was observed. Consequently, cell shrinkage caused by dehydration decreased the impact of X-ray radiation on mummified cells significantly. Moreover, backscattered electrons in cortical bone protected deeper-lying ancient cells from radiation damage at 80 kVp X-ray

Biological nitrogen fixation and growth parameters correlations of alfalfa (Medicago sativa L.) genotypes under organically managed fields with limited irrigation

To identify the effective characters and their relative importance in improvement of BNF, two separate field experiments were conducted under irrigated and rain-fed organic managements of dry, Pannonian region of east Austria. The experiments were laid out in an α-lattice design with two replications and 18 genotypes (eight Iranian ecotypes and ten European cultivars). Plant height was positively and significantly correlated with leaf area index (LAI) and shoot dry matter (DM) under both conditions. Positive correlations were found between biological nitrogen fixation (BNF) and shoot DM (r = 0.61** and 0.87**, irrigated and rain-fed management, respectively). Regarding correlation coefficients, high yielding genotypes had taller plants and denser stands, especially under rain-fed condition. In path analysis, all direct effects of BNF components were positive in both conditions, while some of the indirect effects were negative. These can be regarded in selection models to avoid undesirable negative effects. Plant height and LAI can be considered as primary selection criteria for improving shoot DM, while crop re-growth and plant height, with antonymous effects, were more important for improving root dry matter

Design of an fMRI-compatible optical touch stripe based on frustrated total internal reflection

Previously we developed a low-cost, multi-configurable handheld response system, using a reflective-type intensity modulated fiber-optic sensor (FOS) [1] to accurately gather participants' behavioral responses during functional magnetic resonance imaging (fMRI). Inspired by the popularity and omnipresence of the fingertip-based touch sensing user interface devices, in this paper we present the design of a prototype fMRI-compatible optical touch stripe (OTS) as an alternative configuration. The prototype device takes advantage of a proven frustrated total internal reflection (FTIR) technique. By using a custom-built wedge-shaped optically transparent acrylic prism as an optical waveguide, and a plano-concave lens to provide the required light beam profile, the position of a fingertip touching the surface of the wedge prism can be determined from the deflected light beams that become trapped within the prism by total internal reflection. To achieve maximum sensitivity, the optical design of the wedge prism and lens were optimized through a series of light beam simulations using WinLens 3D Basic software suite. Furthermore, OTS performance and MRI-compatibility were assessed on a 3.0 Tesla MRI scanner running echo planar imaging (EPI) sequences. The results show that the OTS can detect a touch signal at high spatial resolution (about 0.5 cm), and is well suited for use within the MRI environment with average time-variant signal-to-noise ratio (tSNR) loss <; 3%