195 research outputs found

    Sopra una fibula d'oro trovata presso Palestrina

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    Mode of access: Internet

    QualitÀtsmanagement nach DIN EN ISO 9001: 2000 an der HNO-UniversitÀtsklinik Frankfurt/Main

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    Im Jahr 2003 begann die HNO-UniversitĂ€tsklinik Frankfurt / Main mit der EinfĂŒhrung eines QualitĂ€tsmanagement-Systems, die im August 2005 zur erfolgreichen Zertifizierung nach der vom Klinikumsvorstand geforderten DIN EN ISO 9001:2000 fĂŒhrte. Ziele unseres QualitĂ€tsmanagements waren die Optimierung der internen BetriebsablĂ€ufe und die Standardisierung von ArbeitsvorgĂ€ngen unter Einbeziehung von logistischen Schnittstellen mit externen Strukturen unter BerĂŒcksichtigung der besonderen Anforderungen einer UniversitĂ€tsklinik. Neben einer grundsĂ€tzlichen PrĂŒfung und Optimierung sĂ€mtlicher OrganisationsablĂ€ufe wurden fĂŒr die Kernprozesse unserer Klinik Zielvorgaben festgelegt. Diese Ziele betrafen die QualitĂ€t der ArbeitsablĂ€ufe fĂŒr alle Bereiche der HNO-Ă€rztlichen ambulanten und stationĂ€ren Versorgung ebenso, wie Aufgaben in Forschung und Lehre, die durch ein Ausbildungscurriculum fĂŒr Mitarbeiter und Sudenten abgebildet wurde. Es wurden aber auch Serviceaspekte, wie Terminvergabe und BefundĂŒbermittlung, sowie ökonomische und wirtschaftliche Aspekte unserer Arbeit optimiert. Durch Umstrukturierung und Neuorganisation konnte die Effizienz der ArbeitsablĂ€ufe deutlich gesteigert werden, wovon vor allem Patienten und Mitarbeiter erheblich profitieren. Die EinfĂŒhrung eines QualitĂ€tsmanagementsystems in der Frankfurter HNO-UniversitĂ€tsklinik war zunĂ€chst mit einem entsprechenden Arbeitsaufwand verbunden und erforderte ein Umdenken in den einzelnen Funktionsbereichen. Insgesamt ĂŒberwiegt der positive Einfluss auf die Struktur und ArbeitsablĂ€ufe, sodass die Umsetzung eines QualitĂ€tsmanagementsystems in der UniversitĂ€tsklinik empfehlenswert ist

    Optimized Approach for Determination of the Solid Temperature in a Steam Turbine in Warm-Keeping-Operation

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    International audienceThe determination of the temperature distribution in the thick-walled components in steam turbines is increasing in relevance. Due to the growing share of volatile renewable power generation, power plants with a high flexibility and a high integral efficiency are required. e current operational conditions lead to high thermal stresses inside the heavy components and thus to a reduced lifetime. To improve the ability for a fast start-up, the steam turbine can be kept warm during a longer period of stand still. Therefore, information about the metal temperature inside the rotor and the casing are crucial. However, the temperature distribution of the inner casing and especially the rotor cannot be measured without high additional effort. us, a calculation model with sufficient accuracy and also manageable calculation effort is required. In the present work, a hybrid-numerical FEM and analytical-approach has been developed to calculate the solid body temperatures of a steam turbine in warm-keeping operation in a most efficient way. The presented model provides accuracy of nearly % compared with Conjugate-Heat-Transfer simulations with a simultaneously reduced calculation effort by a factor of more than

    Langzeiterfahrungen mit der ipsilateralen Elektroakustischen Stimulation (EAS) : meeting abstract

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    Hochgradig hörgeschĂ€digten Patienten mit einem Tieftonrestgehör (Steilabfall im Audiogramm) können mittels ipsilateraler EAS versorgt werden. Dabei wird der völlig taube Hochfrequenzbereich des Innenohres mit einem Cochleaimplantat stimuliert, und die tieffrequente Restfunktion der Schnecke bleibt erhalten. Voraussetzung fĂŒr eine derartige Versorgung ist ein Erhalt des tieffrequenten Restgehöres bei der Cochlea-Implant-ElektrodeneinfĂŒhrung. Im Rahmen einer klinischen Studie wurden seit 1999 in Frankfurt 25 Patienten mit EAS versorgt. Des Weiteren wurden 16 Patienten im Rahmen einer europĂ€ischen Multicenterstudie fĂŒr EAS implantiert. Ein zumindest teilweiser Erhalt des Restgehöres war in ĂŒber 90% der FĂ€lle möglich. Es wird ĂŒber die Langzeitergebnisse (6 bis 70 Monate) nach EAS-Implantation berichtet. In 70% der FĂ€lle blieb das erhaltene Restgehör stabil. Die Patienten zeigten ĂŒberdurchschnittlich gute Werte bei der Sprachdiskrimination mit ihren Cochleaimplantaten, die durch zusĂ€tzliche akustische Stimulation noch verbessert wurden. Besonders deutlich waren die Hörleistungen unter StörgerĂ€uscheinfluss. Seit Kurzem steht auch ein kombinierter Sprachprozessor fĂŒr die elektrische und akustische Stimulation zur VerfĂŒgung

    Test Rig for Applied Experimental Investigations of the Thermal Contact Resistance at the Blade-Rotor-Connection in a Steam Turbine

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    International audienceStudies have shown that in a pre-warming respectively warm-keeping operation of a steam turbine, the blades and vanes transport most of the heat to the thick-walled casing and rotor. Thereby, a bottle-neck arises at the connection between the blade root and the rotor. The contact heat resistance at these interfaces affects the temperature distribution and thus the thermal stresses in the rotor. The present paper introduces a thermal contact resistance test rig, which is designed to quantify the contact heat transfer at the blade-rotor-connection of a steam turbine. An uncertainty analysis is presented which proves that the average measurement uncertainties are less than one percent. In addition to the test rig, a numerical model of the specimen for the determination of the thermal contact resistance is developed and introduced. Results of several steady-state measurements under atmospheric and evacuated atmosphere using a highly temperature-resistant chromium molybdenum steel are shown. As a main influence parameter the contact pressure is investigated, which is affected by the rotational speed of the turbine. The investigations show a significant contact heat resistance especially at small contact pressures

    Metabolic Signature of Atypical Fibroxanthoma and Pleomorphic Dermal Sarcoma: Expression of Hypoxia-inducible Factor-1α and Several of Its Downstream Targets

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    Metabolic reprogramming mediated by hypoxia-inducible factors play a crucial role in many human cancers. HIF-1α is activated under hypoxic conditions and is considered a key regulator of oxygen homoeostasis during tumor proliferation under hypoxia. Aim of this research was to analyze the immunohistochemical expression of HIF-1α, VEGF-A, Glut-1, MCT4, and CAIX in atypical fibroxanthoma (AFX) and pleomorphic dermal sarcoma (PDS). 21 paraffin-embedded AFX and 22 PDS were analysed by immunohistochemis-try, namely HIF-1α, VEGF-A (referred to as VEGF throughout the manuscript), Glut-1, MCT4, and CAIX. To quantify the protein expression, we considered the percentage of positive tumor cells (0: 0%, 1: up to 1%, 2: 2-10%, 3: 11-50%, 4: >50%) in relation to the staining intensity (0: negative, 1: low, 2: medium, 3: strong). HIF-1α expression (mean ± SD) in AFX (9.33±2.92) was significantly stronger than that in PDS (5.90±4.38; P= 0.007), whereas the expression of VEGF, Glut-1, MCT4, and CAIX did not show differences between AFX and PDS. When comparing all tumors without subgroup stratification, the expression of HIF-1α (P= 0.044) and MCT4 (P= 0.036) was significantly stronger in ulcerated tumors than in tumors without ulceration. Our findings provide the first evidence that HIF-1α-induced metabolic reprogramming may contribute to the pathogenesis of AFX and PDS. HIF-1α expression seems to be higher in AFX than in PDS, and ulcerated tumors show higher expression levels of HIF-1α and MCT4 irrespective of the diagnosis

    Macular hole surgery: an analysis of risk factors for the anatomical outcome with special emphasis on the experience of the surgeon

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    Purpose: The aim of this study was to evaluate risk factors for the anatomical and functional outcomes of macular hole (MH) surgery with special emphasis on the experience of the surgeon. Methods: A total of 225 surgeries on idiopathic MHs (IMHs) performed by 6 surgeons with a mean follow-up period of 20.5 months were reviewed in this retrospective study. Outcome parameters focused on IMH closure, complications and visual acuity improvement. The results of MH surgeries performed by experienced surgeons were compared to those of surgeons in training. Results: The average MH size was 381 ”m (standard deviation [SD]=168). Brilliant blue G (BBG) for internal limiting membrane (ILM) staining was used in 109 (48%) eyes and indocyanine green (ICG) in 116 (52%) eyes. As endotamponade, 20% SF6 was used in 38 (17%) cases, 16% C2F6 in 33 (15%) cases and 16% C3F8 in 154 (68%) cases. IMH closure was achieved in 194 eyes (86%). Mean preoperative visual acuity was 0.84 logarithm of the minimum angle of resolution (log MAR; SD=0.29, range: 0.3–1.5); surgery led to a mean improvement of 0.40 (SD=0.37) log MAR. Although the MH closure rate was the same using BBG or ICG for ILM peeling, visual acuity improvement was better in eyes peeled with BBG compared to eyes peeled with ICG (log MAR: BBG: 0.38 [95% CI: 0.32, 0.44] vs ICG: 0.48 [95% CI: 0.42, 0.54], P=0.029). Surgeons with previous experience in vitreoretinal surgery of ≄6 years achieved better visual outcomes compared to surgeons with 0–3 years of experience, regardless of the MH size, preoperative visual acuity, time to follow-up or dye used for ILM peeling (0–3 years [0.27, ∆log MAR] vs ≄6 years [0.43, ∆log MAR], P=0.009). Conclusion: Our results indicate that vitrectomy with ILM peeling performed by non-experienced surgeons is a safe procedure leading to good anatomical and functional results. Very experienced surgeons may achieve even better functional outcomes

    An organometallic chimie douce approach to new Re(x)W(1-x)O3 phases

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    Re(x)W(1-x)O3.H2O and Re(x)W(1-x)O3 phases are prepared by a new organometallic chimie douce concept employing the organometallic precursor methyltrioxorhenium.Comment: 3 pages, 6 figures, submitted to Chem. Com

    In vivo alkaline comet assay: Statistical considerations on historical negative and positive control data

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    The alkaline comet assay is frequently used as in vivo follow-up test within different regulatory environments to characterize the DNA-damaging potential of different test items. The corresponding OECD Test guideline 489 highlights the importance of statistical analyses and historical control data (HCD) but does not provide detailed procedures. Therefore, the working group “Statistics” of the German-speaking Society for Environmental Mutation Research (GUM) collected HCD from five laboratories and >200 comet assay studies and performed several statistical analyses. Key results included that (I) observed large inter-laboratory effects argue against the use of absolute quality thresholds, (II) > 50% zero values on a slide are considered problematic, due to their influence on slide or animal summary statistics, (III) the type of summarizing measure for single-cell data (e.g., median, arithmetic and geometric mean) may lead to extreme differences in resulting animal tail intensities and study outcome in the HCD. These summarizing values increase the reliability of analysis results by better meeting statistical model assumptions, but at the cost of information loss. Furthermore, the relation between negative and positive control groups in the data set was always satisfactorily (or sufficiently) based on ratio, difference and quantile analyses
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