Die Irisdiagnose ist ein noninvasives Verfahren aus dem Bereich der Komplementärmedizin, durch das Erkrankungen anhand von Veränderungen der Pigmentation und Struktur der Iris erkannt werden sollen.

Background. Iridology is a noninvasive method from the field of complementary medicine that is said to detect diseases by looking for abnormalities of pigmentation and structure in the iris. Colorectal cancer is an ideal opportunity for screening programs because of its long period of development. Our study investigated the applicability of iridology as an alternative screening method for colorectal cancer. Methods. Digital color slides were obtained from both eyes of 29 patients with histologically diagnosed colorectal cancer and from 29 age- and gender-matched healthy control subjects. The slides were presented in random order to acknowledged iridologists without knowledge of the number of patients in the two categories. Results. The iridologists correctly detected 51.7% and 53.4%, respectively, of the patients' slides; therefore, the likelihood was statistically no better than chance. Sensitivity was, respectively, 58.6% and 55.2%, and specificity was 44.8% and 51.7%. Conclusion. Iridology had no validity as a diagnostic tool for detecting colorectal cancer in this study.

The objectives of this workshop are to provide an overview of the different commercially available PET/CT scanners and to gain the necessary knowledge of PET/CT QC/QA procedures as well as the criteria needed for PET scanner accreditation and acceptance testing. The first objective will be met during the first day whereby three presentations will be provided covering the PET/CT scanner offerings from GE Health Care, Siemens Medical Solutions, and Philips Medical Systems respectively. The presentations will focus on PET scanner design, performance, and capabilities and will be given by respective users of the equipment rather than representatives of the manufacturers. The second objective will be met during the second day of the workshop, whereby four speakers will discuss topics on PET/CT QC/QA procedures, PET NEMA acceptance testing, PET ACR accreditation, and PET site shielding calculations and requirements.

Measurements of C2–C5 hydrocarbons on an hourly basis at the TNO site in Delft from 1982 to 1984 and at Moerdijk over the period 1981–1991 are presented. In combination with meteorological data (wind direction and wind speed) the Delft and Moerdijk series are evaluated to identify source categories, annual variations, background concentrations and trends. The C2–C5 hydrocarbon concentrations at Delft and Moerdijk are determined mainly by emission characteristics and meteorological dispersion; the dominant sources are relatively nearby and atmospheric degradation is not of much importance. Under conditions of high wind speed the concentrations measured at Moerdijk in the marine sector are close to the Atlantic background concentrations in winter and somewhat above this in summer. The continental background concentrations are higher than the marine background concentrations by a factor of almost two. The annual variation of acetylene is more pronounced than that of the other hydrocarbons, most likely due to a different seasonal variation in acetylene emissions. The annual variation of propene is smoother, indicating stronger sources in summer than in winter. This feature of propene is observed in continental as well as in marine sectors. The observations show that at Moerdijk C2–C4 concentrations measured in Rijnmond sector have decreased considerably since the early 1980s, corresponding with changes in emissions in that area. Averaged over all wind directions the trend of all species is downward, but for acetylene the trend is significant at a 95% confidence interval. The acetylene concentrations show an annual downward trend of 3% during the 1980s, supporting other estimates of decreasing hydrocarbon emissions from traffic over this period at the same rate.

Eulerian grid models are used to calculate the ozone formation in the troposhere over Europe. It is of primary importance, both from a scientific point of view as well as in establishing the benefits of abatement strategies by using these models, to be able to determine the reliability of these models. Currently, no consistent and generally accepted method exists to determine this reliability. Comparing measured with calculated ozone concentrations at the same location is insufficient for determining the performance of models. Multicomponent analysis and assessment of observed phenomena are essential ingredients of a methodology for model validation.

The atmosphere is a very complex, open, dynamic and multi-causal relation system in which non-linear processes and feedback mechanisms play an important role. Research within this subtheme in NRP-1 focused on uncertainties in our understanding of three issues i.o. o − the role of clouds and aerosols on the radiation budget − the role of atmospheric ozone in global change and the effect of atmospheric change on UV-B climatology − trophospheric budgets of non CO2 greenhouse gases These issues are being dealt with in 12 projects. On average good progress has been made in many of the projects and through there are some weaknesses, the overall quality of science and technological developments is good and in some cases even excellent in comparison to international standards. Links with international programmes such as IGBP, CEC, EUREKA/EUROTRAC are well established.

The poster and this paper consist of two parts: (1) Concentrations and internal production of ozone in Europe in relation to different concepts of the critical levels and (2) Exchange of ozone between the atmospheric boundary layer and the free troposphere. The first part describes the evaluation of 1989 ozone data from the EUROTRAC Tropospheric Ozone Research (TOR) project and the Co-operative Programme for Monitoring and Evaluation of Long-range Transmission of Air Pollutants in Europe (EMEP). The data mostly from central and northwestern Europe, show that independent of ways of formulating the critical levels, there are exceedances over large parts of Europe. The second part shows results from a Data Analysis Model that evaluates the transfer of air from the atmospheric boundary layer (ABL) to the free troposphere (FT) and vice versa. This quantity is of importance since it determines the effective emissions of shorter lived species to the global atmosphere. The model was run for the full year of 1989 to study the exchange processes at the location of Uccle (B). For the summer months June, July and August the results releal a net ABL to FT flux of O 3 with a magnitude of 0.43 * 10 −3 mole m −2 day −1 . This number is in agreement with values derived from transport models.

The present-day capabilities of the solid sampling AAS are faced with the profile of requirements of the industrial practice on chemical trace analysis.

Addition of fine grained elemental nickel stabilizes selenium in inorganic solid samples, so that no selenium losses can be detected up to 2,000 °C pretreatment temperature. The specific absorption signals of selenium are significantly broadened and delayed. Interferences by sulphur are overcome by this effect, because the sulphur compounds appear in the gas phase before selenium. For organic materials, however, the addition of nickel as matrix modifier for solid sampling ZAAS fails.

A report is given on the successful application of direct ZAAS as a trace-analytical tool for inorganic materials characteristically occurring in cement industries. Results of interlaboratory studies and analysis of standard reference materials for important elements as As, Cd, Cr, Hg, Tl and others are discussed in detail.