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3. Zyklische Auslastungsgrade der FKM‐Richtlinien: Definition und Vorschlag eines effizienten Iterationsverfahrens.

Author

Fiedler, M., Weichert, J., and Rennert, R.

Subjects
*NEWTON-Raphson method, *DERIVATIVES (Mathematics), *MINERS, *DEFINITIONS
Abstract

The FKM guideline nonlinear published in 2019 does not yet contain a definition for a cyclic utilization rate in the load direction. One of the reasons is the nonlinear material behavior, which makes it difficult to calculate a utilization rate in the load direction. In order to enable the definition of a cyclic utilization rate, the cyclic utilization rate according to the FKM guideline "Analytical Strength Assessment" (FKM linear) is examined in more detail and a proposal is made for an efficient iteration procedure for the calculation of the utilization rate based on the consequent Miner rule. This iteration procedure has an accuracy comparable to that of Newton's method. Unlike FKM linear, the FKM guideline nonlinear takes nonlinear elastic‐plastic material behavior into account when calculating component fatigue lives. This results in a nonlinearity in the calculation, which makes it difficult to define an objective function for the Newton method. Currently, the user can only use interval nesting, which requires considerable computational effort. The newly introduced efficient iteration method does not require the definition of an objective function and its derivative in order to calculate the next iteration value. The introduction of the efficient iteration procedure thus allows for the first time the fast calculation of a cyclic utilization rate based on FKM guideline nonlinear. The utilization rate is therefore defined for the first time within in this paper, including a termination criterion. [ABSTRACT FROM AUTHOR]

Published
2023
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9. Fokus Neurologische Intensivmedizin

Author

Michalski, D., Jungk, C., Brenner, T., Dietrich, M., Nusshag, C., Reuß, C. J., Fiedler, M. O., Bernhard, M., Beynon, C., and Weigand, M. A.

Subjects
Journal Club
Published
2020

28. Postflight Quiet Stance Stability of Astronauts Following Recovery From a Simulated Fall

Author

Reschke, M. F, Kofman, I. S, Fisher, E. A, Cerisano, J. M, Lawrence, E. L, Peters, B. T, Harm, D. L, Kulecz, W, Mulavara, A. P, Fiedler, M. J, and Bloomberg, J. J

Subjects
Aerospace Medicine
Abstract

INTRODUCTION: Astronauts returning from space flight universally present with postural ataxia. Throughout the Space Shuttle Program, measurement of ataxia has concentrated on sway in the anterior-posterior plane. Implementation of an interdisciplinary pre- and postflight study (Functional Task Test, FTT) designed to evaluate both astronaut postflight functional performance and related physiological changes has allowed the investigation of postural instability by characterizing dynamic stabilographic sway patterns. METHODS: Six astronauts from short-duration (Shuttle) and three from long-duration (ISS) flights were required to recover from a simulated fall. Subjects with eyes open, wearing running shoes lay prone on the floor for 2 minutes and then quickly stood up, maintained a quiet stance for 3 minutes, arms relaxed along the side of the body, and feet comfortably placed on the force plate. Crewmembers were tested twice before flight, on landing day (Shuttle only), and 1, 6, and 30 days after flight. Anterior-posterior (AP) and medial-lateral (ML) center-of-pressure (COP) coordinates were calculated from the ground reaction forces collected at 500 Hz. The 3-minute quiet stance trial was broken into three 1-minute segments for stabilogram diffusion analysis. A mean sway speed (rate of change of COP displacement) was also calculated as an additional postural stability parameter. RESULTS/CONCLUSION: While there was considerable variation, most of crewmembers tested exhibited increased stochastic activity evidenced by larger short-term COP diffusion coefficients postflight in both the AP and ML planes, suggesting significant changes in postural control mechanisms, particularly control of lower limb muscle function. As expected, postural instability of ISS astronauts on the first day postflight was similar to that of Shuttle crewmembers on landing day. Recoveries of stochastic activity and mean sway speed to baseline levels were typically observed by the 30th day postflight for both long-duration and short-duration crewmembers. Dynamic postural stability characteristics obtained in this low-impact study complement the data measured with computerized dynamic posturography.

Published
2010

39. Hemikolektomie bei Kolonischämie

Author

Vernadakis, S., Adamzik, M., Heuer, M., Antoch, G., Baba, H., Fiedler, M., Buer, J., Paul, A., and Kaiser, G.M.

Subjects
Adult, H1N1-assoziierter Todesfall, Viszerale Komplikationen, Kasuistiken, Darmischämie, Influenza A (H1N1) virus, Obesity, Morbid, Visceral complications, Fatal Outcome, Influenza A Virus, H1N1 Subtype, H1N1-associated death, Sepsis, Influenza, Human, Humans, Female, Influenza-A (H1N1)-Virus, Colectomy, Colon ischemia
Abstract

Zusammenfassung Die Pandemie mit dem neuen Influenza-A (H1N1)-Virus breitet sich zunehmend in Deutschland aus. Es kommt vermehrt zu hospitalisierungspflichtigen und schweren Verläufen mit tödlichem Ausgang, insbesondere bei Patienten mit Risikofaktoren aufgrund eines chronischen Grundleidens. Bis Mitte Dezember 2009 wurden in Deutschland 119 Todesfälle registriert. Wir berichten über den ersten H1N1-assoziierten Todesfall einer 36-jährigen Patientin mit schwerer Adipositas in Deutschland. Dabei war durch eine viszerale Komplikation (Kolonischämie bedingt durch pharmakologisch begünstigten Darmperfussionsausfall bei schwerer Sepsis) eine Laparotomie mit Kolonresektion erforderlich. Es wird für diesen besonderen Fall die Logistik der Behandlung mit allen erforderlichen diagnostischen und auch operativen Schritten dargestellt. Ferner werden an diesem Beispiel die hygienischen und arbeitsschutztechnischen Vorkehrungen, die eine Gefährdung des medizinischen Personals minimieren, erörtert. Trotz aller Sicherheitsvorkehrungen bei der Behandlung infektiöser Patienten gilt die Immunisierung des medizinischen Personals sowie der Risikopatienten als alleinige wirksame und sichere vorbeugende Maßnahme gegen das neue Influenza-A-Virus.

Published
2010

40. High precision study of chemical relaxation in the system N2O4=2NO2 by photoacoustic resonance spectroscopy.

Author

Fiedler, M. and Hess, P.

Subjects
*RELAXATION phenomena, *PHOTOACOUSTIC spectroscopy
Abstract

The chemical relaxation of the N2O4 dissociation was studied using Ar+ laser excited acoustic resonances of a cylindrical cavity. The resonance profiles of the first radial mode were measured as a function of pressure and temperature by a computer controlled setup. The N2O4 dissociation rate constant and the mean rotational and vibrational relaxation time of the N2O4–NO2 mixture were obtained for temperatures between 273 and 317 K by fitting a detailed theoretical model of the resonator to the measured values for frequency dispersion, resonance broadening, and strength of the photoacoustic signal. Excellent agreement between theory and experiment was obtained for the frequency dispersion and the photoacoustic signal. An empirical correction function had to be introduced to account for discrepancies between the theoretically predicted and measured values of the resonance broadening which was in the percent region. A value of 6.1×10-15 cm3/molecule s was determined for the rate constant of N2O4 dissociation in the low pressure limit at 298 K. The activation energy of the N2O4 dissociation for 20 mbar pressure was determined to be EA=36 kJ/mol. A comparison of the measured low-pressure limit of the unimolecular rate constant with theoretical predictions of RRKM theory yielded values for the mean collision efficiency of N2O4 and NO2 between 0.95 and 0.5 in the temperature range 273–317 K. [ABSTRACT FROM AUTHOR]

Published
1990
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42. Molecular genetic analysis of vesicular transport in Aspergillus niger reveals partial conservation of the molecular mechanism of exocytosis in fungi

Author

Kwon, M.J., Arentshorst, M., Fiedler, M., Groen,F.L.M. de, Punt, P.J., Meyer, V., and Ram, A.F.J

Subjects
MSB - Microbiology and Systems Biology, Life, parasitic diseases, fungi, Food and Nutrition, ELSS - Earth, Life and Social Sciences, Healthy Living, Nutrition
Abstract

The filamentous fungus Aspergillus niger is an industrially exploited protein expression platform, well known for its capacity to secrete high levels of proteins. To study the process of protein secretion in A. niger, we established a GFP-v-SNARE reporter strain in which the trafficking and dynamics of secretory vesicles can be followed in vivo. The biological role of putative A. niger orthologues of seven secretion-specific genes, known to function in key aspects of the protein secretion machinery in Saccharomyces cerevisiae, was analysed by constructing respective gene deletion mutants in the GFP-v-SNARE reporter strain. Comparison of the deletion phenotype of conserved proteins functioning in the secretory pathway revealed common features but also interesting differences between S. cerevisiae and A. niger. Deletion of the S. cerevisiae Sec2p orthologue in A. niger (SecB), encoding a guanine exchange factor for the GTPase Sec4p (SrgA in A. niger), did not have an obvious phenotype, while SEC2 deletion in S. cerevisiae is lethal. Similarly, deletion of the A. niger orthologue of the S. cerevisiae exocyst subunit Sec3p (SecC) did not result in a lethal phenotype as in S. cerevisiae, although severe growth reduction of A. niger was observed. Deletion of secA, secH and ssoA (encoding SecA, SecH and SsoA the A. niger orthologues of S. cerevisiae Sec1p, Sec8p and Sso1/2p, respectively) showed that these genes are essential for A. niger, similar to the situation in S. cerevisiae. These data demonstrate that the orchestration of exocyst-mediated vesicle transport is only partially conserved in S. cerevisiae and A. niger.

Published
2014

46. Total neutrino and antineutrino charged current cross section measurements in 100, 160, and 200 GeV narrow band beams

Author

Berge, P., Blondel, A., Böckmann, P., Burkhardt, H., Dydak, F., De Groot, J. G. H., Grant, A. L., Hagelberg, R., Hughes, E. W., Krasny, M., Meyer, H. J., Palazzi, P., Ranjard, F., Rothberg, J., Steinberger, J., Taureg, H., Wachsmuth, H., Wahl, H., Williams, R. W., Wotschack, J., Wysłouch, B., Blümer, H., Brummel, H. D., Buchholz, P., Duda, J., Eisele, F., Kampschulte, B., Kleinknecht, K., Knobloch, J., Müller, E., Pszola, B., Renk, B., Belusević, R., Falkenburg, B., Fiedler, M., Geiges, R., Geweniger, C., Hepp, V., Keilwerth, H., Kurz, N., Tittel, K., Debu, P., Guyot, C., Merlo, J. P., Para, A., Perez, P., Perrier, F., Rander, J., Schuller, J. P., Turlay, R., Vallage, B., Abramowicz, H., Królikowski, J., and Lipniacka, A.

Published
1987
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49. Proof of concept for an optogalvanic gas sensor for NO based on Rydberg excitations.

Author

Schmidt, J., Fiedler, M., Albrecht, R., Djekic, D., Schalberger, P., Baur, H., Löw, R., Fruehauf, N., Pfau, T., Anders, J., Grant, E. R., and Kübler, H.

Subjects
*RYDBERG states, *NITRIC oxide, *GAS mixtures, *ATMOSPHERIC pressure, *HELIUM
Abstract

We demonstrate the applicability of 2-photon Rydberg excitations of nitric oxide (NO) at room temperature in a gas mixture with helium (He) as an optogalvanic gas sensor. The charges created initially from preceding collisions of excited NO Rydberg molecules with free electrons are measured as a current on metallic electrodes inside a glass cell and amplified using a custom-designed high-bandwidth transimpedance amplifier attached to the cell. We find that this gas sensing method is capable of detecting NO concentrations lower than 10 ppm even at atmospheric pressures, currently only limited by the way we prepare gas dilutions. [ABSTRACT FROM AUTHOR]

Published
2018
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50. Distribute the Video Frame Pixels over the Streaming Video Sequence as Sub-Frames

Author

Aziz, H. M., Fiedler, M., Håkan Grahn, and Lundberg, L.

Subjects
wireless network, Datavetenskap (datalogi), Computer Sciences, frame splitting, ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, sub-frame crossing, streaming video, rate adaptation
Abstract

Real-time video streaming over wireless channel has become an important issue due to the limited bandwidth that is unable to handle the flow of information of the video frames. The characteristics of wireless networks in terms of the available bandwidth, frame delay, and frame losses cannot be known in advance. As the effect of that, the user may notice a frozen picture in the mobile screen. In this work, we propose a technique to prevent freezing frames in the mobile devices based on spatial and temporal locality for the video stream, by splitting the video frame into four sub-frames and combining them with another sub-frames from different sequence positions in the streaming video. In case of frames losses, there is still a possibility that one fourth (one sub-frame) of the frame will be received by the mobile device. The received sub-frames will be reconstructed based on the surrounding pixels. The rate adaptation mechanism will be also highlighted in this work, by skipping sub-frames from the video frames. We show that the server can skip up to 75% of the frame’s pixels and the receiving pixels (sub-frames) can be reconstructed to acceptable quality in the mobile device.

Published
2012

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