Search

Purpose. This study aims to describe the profile progression from cornea over limbus to sclera using the module CSP-Re- port (Corneo-Skleral-Profil-Report) of the Oculus Pentacam. Material and Methods. Seventy-four left eyes of healthy sub- jects were evaluated. Data was collected as part of previous research (bachelor-thesis) using the CSP-Report module of the Pentacam Basic. Sagittal height, limbal angle and scleral angle were analyzed over three diameters in eight semi- meridians. Results. At diameter 10.00 mm the shape of the anterior segment of the eye was nearly rotationally symmetrical, the average sagittal height of the eight semi-meridians was between 1734 µm and 1806 µm. At diameter 12.80 mm the shape was more asymmetrical, average sagittal height ranged from 2797 µm to 3000 µm. At diameter 15.00 mm the asym- metry was most pronounced, the average sagittal height was between 3595 µm and 4033 µm. The average limbal angles at 12.80 mm were in the range of 35.68° and 42.02°. For the scleral angle at 15.00 mm mean values between 34.71° and 43.11° were determined for the eight semi-meridians. The nasal segments always showed smaller sagittal heights, accompanied by smaller limbal and scleral angles compared to the temporal semi-meridians. The same pattern was obser- ved for the superior semi-meridians in relation to the inferior segments. For the nasal semi-meridians, concave transitions of the corneo-scleral profile were observed, whereas tempo- rally a convex course of the CSP was observed. Conclusion. The CSP-Report provides a method to describe the shape of the anterior segment of the eye. These additional data are useful for fitting scleral lenses. Keywords Scheimpflug technology, Pentacam, limbal sclera contour, corneo-scleral profile, scleral lens, sagittal height

Research data management (RDM) requires standards, policies, and guidelines. Findable, accessible, interoperable, and reusable (FAIR) data management is critical for sustainable research. Therefore, collaborative approaches for managing FAIR-structured data are becoming increasingly important for long-term, sustainable RDM. However, they are rather hesitantly applied in bioengineering. One of the reasons may be found in the interdisciplinary character of the research field. In addition, bioengineering as application of principles of biology and tools of process engineering, often have to meet different criteria. In consequence, RDM is complicated by the fact that researchers from different scientific institutions must meet the criteria of their home institution, which can lead to additional conflicts. Therefore, centrally provided general repositories implementing a collaborative approach that enables data storage from the outset In a biotechnology research network with over 20 tandem projects, it was demonstrated how FAIR-RDM can be implemented through a collaborative approach and the use of a data structure. In addition, the importance of a structure within a repository was demonstrated to keep biotechnology research data available throughout the entire data lifecycle. Furthermore, the biotechnology research network highlighted the importance of a structure within a repository to keep research data available throughout the entire data lifecycle.

With increased career opportunities as well as uncertainty, individuals strive to not only adapt to changing circumstances but also define their career intentions according to their values and stre...

A reference database was used for the estimation of the standard uncertainties resulting from sampling, sample preparation, and analysis of soil samples from a target area in Switzerland. This evaluation was based on an extended reference sampling of the Comparative Evaluation of European Methods for Sampling and Sample Preparation of Soils Project. Samples were taken according to the national sampling protocols of 15 European countries and were analyzed for zinc, cadmium, copper, and lead. The combined uncertainty for all laboratories was estimated according to the ISO Guide to the Expression of Uncertainty in Measurement. It was found that the sampling uncertainty was not larger than the analytical uncertainty if more than ten sample increments were taken. The uncertainty due to variation in sampling depth and sample size reduction was only significant under unfavorable conditions. On the basis of an uncertainty budget the sampling protocols can be optimized and a ranking is possible, aimed at conditions that are fit for the specific purpose.

Solid sample graphite furnace atomic absorption spectroscopy (SS-GFAAS) has been proposed since its appearance as a good alternative to wet methods of analysis in many matrices. Here, we examine the use of SS-GFAAS for total and leachable arsenic determination in sediments from distinct origins. Our direct analysis of seven selected sediments was not always free of spectral matrix interference, but the spectroscopic technique gave very good results for (a) direct arsenic measurement in solid residues from a range of leaching processes, (b) total arsenic determination (HNO3 leaching test) and (c) the evaluation of its potential remobilisation (modified BCR three-step sequential extraction scheme). For the optimised instrumental conditions, the analysis limit was 0.44 mg kg−1 and long-term reproducibility was between 10–15%. The sum of leachable arsenic in HNO3 65% and the residual fraction, gave recoveries from 72 to 118% of total arsenic content. These results are a good alternative to other cumbersome wet methods involving HF.

Reference materials play a vital role for the verification of the quality control of environmental analysis. In particular, Certified Reference Materials (CRMs) that are certified for a range of chemical parameters are in great demand from routine control laboratories. This article describes the preparation and certification of a white cabbage reference material (BCR-679) certified for a range of trace elements. BCR-679 offers, for the very first time, a certified value for thallium. The new Cabbage BCR-679 is compared with other plant matrices of the BCR/IRMM collection for a range of selected trace metals of environmental concern. Some considerations on moisture are also described.

The combined uncertainty in the analytical results of solid materials for two methods (ET-AAS, analysis after prior sample digestion and direct solid sampling) are derived by applying the Guide to the Expression of Uncertainty in Measurement from the International Standards Organization. For the analysis of solid materials, generally, three uncertainty components must be considered: (i) those in the calibration, (ii) those in the unknown sample measurement and (iii) those in the analytical quality control (AQC) process. The expanded uncertainty limits for the content of cadmium and lead from analytical data of biological samples are calculated with the derived statistical estimates. For both methods the expanded uncertainty intervals are generally of similar width, if all sources of uncertainty are included. The relative uncertainty limits for the determination of cadmium range from 6% to 10%, and for the determination of lead they range from 8% to 16%. However, the different uncertainty components contribute to different degrees. Though with the calibration based on reference solutions (digestion method) the respective contribution may be negligible (precision

One of the major analytical problem in the analysis of fish tissues for total mercury is the dissolution of the sample. This paper compares two different methods of wet digestion (microwave and closed pressurized vessel), followed by FIAAS as final determination and a Zeeman-solid-sample-AAS determination method without previous mineralization. Six fish samples were selected for this study. The top, the central and the bottom portions of the fish were analyzed separately. The mercury contents in the bottom portions determined by Zeeman-solid-sample-AAS were significantly higher than those obtained by the other two systems. A good correlation was observed among the results of the different techniques.

Im Rahmen einer Masterarbeit wurde untersucht, inwieweit es feuerungstechnisch sinnvoll und rechtlich möglich ist, Dinkelspelzen gepresst zu Pellets für eine thermische Nutzung in Kleinfeuerungsanlagen mit einer Nennwärmeleistung von 15 bis 100 kWh zu verwenden. Die bisherigen Entsorgungskosten der Dinkelspelzen, die von der Verarbeitungsindustrie getragen werden müssen, könnten dadurch wegfallen. Mit der thermischen Nutzung von Spelzenpellets ließe sich so auf dezentraler Ebene ein kostengünstiger und CO2-neutraler Brennstoff bereitstellen., LANDTECHNIK, Bd. 62 Nr. 2 (2007)

The present paper presents a feasibility study for the evaluation of mercury mobility in sediments by application of the modified BCR three-step sequential extraction procedure (BCR-SEP). The aim of the study was to evaluate the effect of acidification, reduction and oxidation processes on mercury mobility from sediments, once the SEP was validated with other trace metals. As extractable mercury amounts were mostly found below detection limits of the advanced mercury analyser (AMA-254) used for measuring the extracts (L.D.0.5 ng), the use of a solid sampling atomic absorption spectrometer with a specially designed furnace for Hg atomisation was found to be an optimal technique to quantify Hg in the solid residues coming from the SEP. With this approach, mercury was found to be hardly mobile and only for one of the moderately polluted sediments (BCR CRM 320), extractable mercury (exchangeable fraction, BCR procedure step 1) has been found. An oxidation step with H(2)O(2) was required to obtain extractability up to 64% of the total content in a highly polluted lagoon sediment.

Background: Children are at particular risk for selenium deficiency, which has potentially serious medical implications. Reliable age-specific reference values for serum selenium concentrations in children are sparse, but are essential for the identification of selenium deficiency and decisions regarding selenium supplementation. Methods: Using electrothermal atomic absorption spectrometry, we analyzed serum selenium concentrations from 1010 apparently healthy children (age range, 1 day to 18 years) and from 60 patients on a protein-restricted diet because of inborn errors of metabolism. Reference intervals were defined according to recommended guidelines. Results: Medians for serum selenium concentrations showed a statistically significant age dependency: a decrease from the age Conclusions: Because of nutritional changes, serum selenium concentrations are significantly higher in older children than in infants under 1 year of age. The application of age-adjusted reference values may provide more specific criteria for selenium supplementation. Long-term protein restriction in children is reflected by a failure to achieve higher serum selenium concentrations with increasing age.

In the past, exercises aiming at an assessment of data uncertainty in environmental analysis were usually restricted to the analysis step, while sampling and pre-analytical sample treatment was largely ignored. Collaborative studies on the quantification of sampling errors require, besides a suitable and well characterized test site, the availability of a reference laboratory for the analysis of all of the samples taken in the context of the study by all participants and also test methods which do not contribute large and variable uncertainties due to long and complex analytical methodologies. Here we summarize the major analytical aspects of a European project on the identification and quantification of sampling influences on the determination of lead, cadmium, copper and zinc in soil. The participant group included the leading soil analysis laboratories in Europe; the test site at Dornach (CH) was well suited for the purpose and showed high metal gradients and differentiated land use. The analytical methods (wavelength-dispersive X-ray fluorescence spectrometry and solid-state Zeeman AAS) used in the study showed stable performance characteristics within the confidence interval of the certified reference materials used for the measurement quality control over the entire project period. Additionally, double-blind tests on split samples showed agreement of data in very narrow limits thus demonstrating the reliability of the reference database.

The paper presents an overview about the outcome of two hands-on courses on environmental reference material production organised by the European Commission’s Environment Institute within the context of its PHARE-AQUACON activities. Two plant reference materials, i.e. TP-28 (black tea) and TP-29 (mallow) were prepared and characterised by the course participants. Data on homogeneity and information values about the contents of inorganic and organic pollutants are presented. Furthermore, information about the AQUACON-Project are given, too.