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ZUSAMMENFASSUNG:Bei der elektronenmikroskopischen Abbildung von Einzelmolekulen treten eine Reihe von praparativen, Schwierigkeiten auf, welche dazu gefuhrt haben, daS man trotz zahlreicher Arbeiten diese Methode bisher noch nicht zu einem Standardverfahren entwickeln konnte. Ein Haupthindernis stellt das Auftreten von Artefakten dar, die den nichtkristallinen Polymermolekiilen tauschend ahnlich sehen.Zur Erkennung und Vermeidung dieser ,,ScheinmolekCle" ist es notwendig, quantitative Praparations-und Kontrollmethoden zu entwickeln. Es eignen sich zwei Verfahren : einmal die sogenannte Tropfenmethode und zum anderen die Gefriertrocknuugsmethode. Mit Hilfe dieser Verfahren gelingt es, das Artefaktproblem zn losen und die Homogenitat der Praparate zu testen. SUMMARY:The imaging of single polymer molecules by electron microscopy faces a lot of difficulties with regard to preparation, thus preventing this method from developing to a standard technique, in spite of numerous attempts. A main obstacle is the appearance of artefacts which look strikingly similar to polymer molecules.It is necessary to develop preparation methods enabling quantitative analysis in order

Background Glaucomatous eyes often show strong intraocular pressure (IOP) fluctuations and individual measurements at different time points are necessary for personalized therapy. To survey IOP variations 48-hours diurnal and nocturnal IOP measurements were performed on two consecutive days. Aims of this study were to investigate the short-term repeatability of 48-hours measurements within one patient’s IOP profile and long-term repeatability between two separate IOP profiles of the same patient. Methods A retrospective cohort study was performed evaluating data of 90 glaucoma patients in a German university medical center between 2006 and 2013. All patients underwent two separate diurnal IOP profiles of 48 h. IOP was measured at 8 am, 2 pm, 6 pm, 9 pm using Goldmann applanation tonometry and at 12 midnight using Perkins tonometry in supine position on two consecutive days. Intraclass correlation coefficients (ICC) were calculated to evaluate agreement for the same time points (each time point agreement) and for consecutive measurements within the IOP profiles (between time point agreement). ICC ≤ 0.4 was defined as poor agreement, 0.4–0.75 as moderate and ≥ 0.75 as excellent. Differences between time points were investigated by Bland Altman plots. Results Each time point measurements of profile 1 showed moderate to excellent agreement (ICCs 0.62–0.93). There was a moderate to excellent agreement for measurements between time points of profile 1 (ICCs day one 0.57–0.86, day two 0.71–0.90). Profile 2 was performed at a median interval of 12.0 months (quartiles 11.0 to 21.0). Each time point agreements within profile 2 showed ICCs from 0.23 to 0.81. It showed moderate to excellent agreement for changes between time points (ICCs 0.53–0.94). Day two demonstrated ICCs from 0.74 to 0.88. Long term IOP repeatability (over both pressure profiles) showed moderate to good agreement (ICCs 0.39–0.67). Conclusions Short and long-term agreement of IOP measurements evaluated by diurnal IOP profiles is moderate to good. Due to mostly moderate agreements, which we believe represent IOP fluctuations, we conclude that it is necessary to perform 48-hours IOP profiles to gain a better overview of the individual IOP fluctuations.

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