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941 results on '"Pietsch, U."'

3. Artificial piezoelectricity in centrosymmetric SrTiO3

Author

Khanbabaee, B., Mehner, E., Richter, C., Hanzig, J., Zschornak, M., Pietsch, U., Stöcker, H., Leisegang, T., Meyer, D. C., and Gorfman, S.

Subjects
Condensed Matter - Materials Science
Abstract

Defect engineering is an effective and powerful tool to control existing material properties and create completely new ones, which are symmetry-forbidden in a defect-free crystal. This letter reports on the creation of piezoelectrically active near-surface layer of centrosymmetric SrTiO3, modified by the electric field-induced migration of oxygen vacancies. We provide the unequivocal proof of piezoelectricity through the stroboscopic time-resolved X-ray diffraction under alternating electric field. The magnitude of the discovered piezoelectric effect is comparable with the bulk piezoelectric effect in commercial ferroelectric materials. Such artificially formed defect-mediated piezoelectricity can be important as an alternative road for smart materials design., Comment: 10 pages, 4 figures

Published
2016

4. Norm minimized Scattering Data from Intensity Spectra

Author

Seel, A., Davtyan, A., Pietsch, U., and Loffeld, O.

Subjects
Computer Science - Information Theory
Abstract

We apply the $l_1$ minimizing technique of compressive sensing (CS) to non-linear quadratic observations. For the example of coherent X-ray scattering we provide the formulae for a Kalman filter approach to quadratic CS and show how to reconstruct the scattering data from their spatial intensity distribution., Comment: 26 pages, 10 figures, reordered sections

Published
2015

5. Structural information extracted from the diffraction of XFEL fs-pulses in a crystal

Author

Leonov, A., Ksenzov, D., Benediktovitch, A., Feranchuk, I., and Pietsch, U.

Subjects
Condensed Matter - Materials Science, Physics - Atomic Physics
Abstract

We present a theoretical justification for a method of extracting of supplementary information for the phase retrieval procedure taken from diffraction of fs-pulses from X-ray Free Electron Laser facilities. The approach is based on numerical simulation of the dynamics of the electron density in the crystal composed of different atoms in the unit cell, namely a bi-atomic crystal containing heavy and light atoms. It is shown that evaluation of diffraction intensities measured by means of different values of XFEL pulse parameters enables to find absolute values of structure factors for both types of atoms and their relative phase. The accuracy of structural information is discussed in terms of fluctuations of the evaluated atomic scattering factors. Our approach could be important for improvement of phase retrieval methods with respect to a more efficient determination of atomic positions within the unit cell of macromolecules., Comment: 8 pages; 4 figures

Published
2015

7. Time dependence of X-ray diffraction intensity of a crystal induced by an intense femtosecond X-ray pulse

Author

Leonov, A., Ksenzov, D., Benediktovitch, A., Feranchuk, I., and Pietsch, U.

Subjects
Physics - Atomic Physics, Condensed Matter - Materials Science
Abstract

The time evolution of the electron density and the resulting time dependence of X-ray diffraction peak intensity in a crystal irradiated by highly intense femtosecond pulses of an XFEL is investigated theoretically on the basis of rate equations for bound electrons and the Boltzmann equation for the kinetics of the unbound electron gas that plays an essential role in the time evolution of the electron density of a crystal. The photoionization, Auger process, electron-impact ionization, electron--electron scattering, and three-body recombination have been implemented in the system of rate equations. An algorithm for the numerical solution of the rate equations was simplified by incorporating analytical expressions for the cross sections of all the electron configurations in ions within the framework of the effective charge model. Using this approach we evaluate the time dependence of the inner shell population and electronic kinetic energy during the time of XFEL pulse propagation through the crystal for photon energies between 3 and 12 keV and a pulse width of 40 fs considering a flux of 10^12 ph/pulse (focusing on a spot size of ~ 1 mum^2, this flux corresponds to a fluence ranging between 0.6 and 1.6 mJ/mum^2). The time evolution of the atomic scattering factor and its fluctuation is numerically analyzed for the case of a Silicon crystal taking into account the decrease of the bound electron density during the pulse propagation. The time integrated intensity drops dramatically if the fluence of the XFEL pulse exceeds 1.6 mJ/mum^2., Comment: 19 pages, 15 figures

Published
2013

10. Glass transition in Ultrathin Polymer Films : A Thermal Expansion Study

Author

Bhattacharya, M., Sanyal, M. K., Geue, Th., and Pietsch, U.

Subjects
Condensed Matter - Soft Condensed Matter
Abstract

Glass transition process gets affected in ultrathin films having thickness comparable to the size of the molecules. We observe systematic broadening of glass transition temperature (Tg) as the thickness of the polymer film reduces below the radius of gyration but the change in the average Tg was found to be very small. Existence of reversible negative and positive thermal expansion below and above Tg increased the sensitivity of our thickness measurements performed using energy dispersive x-ray reflectivity. A simple model of Tg variation as a function of depth expected from sliding motion could explain the results. We observe clear glass transition even for 4 nm polystyrene film that was predicted to be absent from ellipsometry measurements of thicker films., Comment: 11 pages, 5 figures

Published
2005
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12. Rettungsdienstliche Betreuung von Mountainbike-Eliterennen

Author

Cajani, S., Fischer, H., and Pietsch, U.

Abstract

Hintergrund: Trotz der steigenden Beliebtheit des Mountainbike-Sports ist die Studienlage zu Verletzungsmustern und Organisation der Rettung im Amateur- und Profibereich spärlich. Für die Betreuung von Grossveranstaltungen wie dem UCI World Cup, den Weltmeisterschaften und dem Swiss Epic Marathon Etappenrennen sind effiziente Rettungskonzepte nötig: Neben dem Downhill muss beim Cross-Country bzw. den Etappen in den Schweizer Alpen des Swiss Epic abgelegenes, schwieriges Gelände abgedeckt sein, dazu kommt das Zuschaueraufgebot in teils grosser Zahl. In diesem Artikel analysieren wir die Verletzungen der Wettbewerbsteilnehmer und beschreiben die verschiedenen Herausforderungen für die Rettungsdienste. Methodik: Retrospektive Analyse der Notfälle beim Swiss Epic von 2016–2020, der UCI-Worldcup Rennen 2015–2017 und 2019 sowie den UCI Weltmeisterschaften 2018. Beschreibung der Organisation der Rettungsdienste; besondere Anforderungen und Streckenkonzepte der Wettbewerbe. Ergebnisse: Signifikant höhere Verletzungswahrscheinlichkeit in der Disziplin Downhill vs. Cross-Country, insbesondere Schädel-Hirn-Traumata und Frakturen der Extremitäten. Im Downhill kam es häufiger zu schweren Traumata (NACA III bis IV) als im Vergleich zu den anderen Disziplinen (p< 0,01). Schlussfolgerung: Jede Veranstaltung benötigt ein Rettungskonzept adaptiert an die Art des Wettbewerbs und der Geländesituation. Es treten wenige, aber relevant schwere Verletzungen auf, deren Versorgung hochqualifiziertes medizinisches Personal und eine effiziente Logistik voraussetzen. GPS-Tracking mit zentraler Disposition der Einsatzmittel ist für Marathonrennen essentiell, stationäre Wettbewerbe profitieren von einer Mischung aus Fixposten und mobilen Einheiten.

Published
2024
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24. Implications of early respiratory support strategies on disease progression in critical COVID-19: a matched subanalysis of the prospective RISC-19-ICU cohort

Author

Wendel Garcia P. D., Aguirre-Bermeo H., Buehler P. K., Alfaro-Farias M., Yuen B., David S., Tschoellitsch T., Wengenmayer T., Korsos A., Fogagnolo A., Kleger G. -R., Wu M. A., Colombo R., Turrini F., Potalivo A., Rezoagli E., Rodriguez-Garcia R., Castro P., Lander-Azcona A., Martin-Delgado M. C., Lozano-Gomez H., Ensner R., Michot M. P., Gehring N., Schott P., Siegemund M., Merki L., Wiegand J., Jeitziner M. M., Laube M., Salomon P., Hillgaertner F., Dullenkopf A., Ksouri H., Cereghetti S., Grazioli S., Burkle C., Marrel J., Fleisch I., Perez M. -H., Baltussen Weber A., Ceruti S., Marquardt K., Hubner T., Redecker H., Studhalter M., Stephan M., Selz D., Pietsch U., Ristic A., Heise A., Meyer zu Bentrup F., Franchitti Laurent M., Fodor P., Gaspert T., Haberthuer C., Colak E., Heuberger D. M., Fumeaux T., Montomoli J., Guerci P., Schuepbach R. A., Hilty M. P., Roche-Campo F., Algaba-Calderon A., Apolo J., Aslanidis T., Babik B., Boroli F., Brem J., Brenni M., Brugger S. D., Camen G., Catena E., Ceriani R., Chau I., Christ A., Cogliati C., Concha P., Delahaye G., Drvaric I., Escos-Orta J., Fabbri S., Facondini F., Filipovic M., Gamez-Zapata J., Gerecke P., Gommers D., Hillermann T., Ince C., Jenni-Moser B., Jovic M., Jurkolow G., Klarer A., Lambert A., Laurent J. -C., Lavanchy J., Lienhardt-Nobbe B., Locher P., Losser M. -R., Lussman R. F., Magliocca A., Margarit A., Martinez A., Mauri R., Mayor-Vazquez E., Meier J., Moret-Bochatay M., Murrone M., Naon D., Neff T., Novy E., Petersen L., Pugin J., Ramelet A. -S., Rilinger J., Rimensberger P. C., Sepulcri M., Shaikh K., Sieber M., Simonini M. S., Spadaro S., Sridharan G. O., Stahl K., Staudacher D. L., Taboada-Fraga X., Tellez A., Urech S., Vitale G., Vizmanos-Lamotte G., Welte T., Zalba-Etayo B., Zellweger N., Graduate School, ACS - Atherosclerosis & ischemic syndromes, ACS - Microcirculation, AII - Inflammatory diseases, RISC-19-ICU Investigators, Wendel Garcia, P.D., Aguirre-Bermeo, H., Buehler, P.K., Alfaro-Farias, M., Yuen, B., David, S., Tschoellitsch, T., Wengenmayer, T., Korsos, A., Fogagnolo, A., Kleger, G.R., Wu, M.A., Colombo, R., Turrini, F., Potalivo, A., Rezoagli, E., Rodríguez-García, R., Castro, P., Lander-Azcona, A., Martín-Delgado, M.C., Lozano-Gómez, H., Ensner, R., Michot, M.P., Gehring, N., Schott, P., Siegemund, M., Merki, L., Wiegand, J., Jeitziner, M.M., Laube, M., Salomon, P., Hillgaertner, F., Dullenkopf, A., Ksouri, H., Cereghetti, S., Grazioli, S., Bürkle, C., Marrel, J., Fleisch, I., Perez, M.H., Baltussen Weber, A., Ceruti, S., Marquardt, K., Hübner, T., Redecker, H., Studhalter, M., Stephan, M., Selz, D., Pietsch, U., Ristic, A., Heise, A., Meyer Zu Bentrup, F., Franchitti Laurent, M., Fodor, P., Gaspert, T., Haberthuer, C., Colak, E., Heuberger, D.M., Fumeaux, T., Montomoli, J., Guerci, P., Schuepbach, R.A., Hilty, M.P., Roche-Campo, F., Algaba-Calderon, A., Apolo, J., Aslanidis, T., Babik, B., Boroli, F., Brem, J., Brenni, M., Brugger, S.D., Camen, G., Catena, E., Ceriani, R., Chau, I., Christ, A., Cogliati, C., Concha, P., Delahaye, G., Drvaric, I., Escós-Orta, J., Fabbri, S., Facondini, F., Filipovic, M., Gámez-Zapata, J., Gerecke, P., Gommers, D., Hillermann, T., Ince, C., Jenni-Moser, B., Jovic, M., Jurkolow, G., Klarer, A., Lambert, A., Laurent, J.C., Lavanchy, J., Lienhardt-Nobbe, B., Locher, P., Losser, M.R., Lussman, R.F., Magliocca, A., Margarit, A., Martínez, A., Mauri, R., Mayor-Vázquez, E., Meier, J., Moret-Bochatay, M., Murrone, M., Naon, D., Neff, T., Novy, E., Petersen, L., Pugin, J., Ramelet, A.S., Rilinger, J., Rimensberger, P.C., Sepulcri, M., Shaikh, K., Sieber, M., Simonini, M.S., Spadaro, S., Sridharan, G.O., Stahl, K., Staudacher, D.L., Taboada-Fraga, X., Tellez, A., Urech, S., Vitale, G., Vizmanos-Lamotte, G., Welte, T., Zalba-Etayo, B., Zellweger, N., Wendel Garcia, P, Aguirre-Bermeo, H, Buehler, P, Alfaro-Farias, M, Yuen, B, David, S, Tschoellitsch, T, Wengenmayer, T, Korsos, A, Fogagnolo, A, Kleger, G, Wu, M, Colombo, R, Turrini, F, Potalivo, A, Rezoagli, E, Rodriguez-Garcia, R, Castro, P, Lander-Azcona, A, Martin-Delgado, M, Lozano-Gomez, H, Ensner, R, Michot, M, Gehring, N, Schott, P, Siegemund, M, Merki, L, Wiegand, J, Jeitziner, M, Laube, M, Salomon, P, Hillgaertner, F, Dullenkopf, A, Ksouri, H, Cereghetti, S, Grazioli, S, Burkle, C, Marrel, J, Fleisch, I, Perez, M, Baltussen Weber, A, Ceruti, S, Marquardt, K, Hubner, T, Redecker, H, Studhalter, M, Stephan, M, Selz, D, Pietsch, U, Ristic, A, Heise, A, Meyer zu Bentrup, F, Franchitti Laurent, M, Fodor, P, Gaspert, T, Haberthuer, C, Colak, E, Heuberger, D, Fumeaux, T, Montomoli, J, Guerci, P, Schuepbach, R, Hilty, M, Roche-Campo, F, Algaba-Calderon, A, Apolo, J, Aslanidis, T, Babik, B, Boroli, F, Brem, J, Brenni, M, Brugger, S, Camen, G, Catena, E, Ceriani, R, Chau, I, Christ, A, Cogliati, C, Concha, P, Delahaye, G, Drvaric, I, Escos-Orta, J, Fabbri, S, Facondini, F, Filipovic, M, Gamez-Zapata, J, Gerecke, P, Gommers, D, Hillermann, T, Ince, C, Jenni-Moser, B, Jovic, M, Jurkolow, G, Klarer, A, Lambert, A, Laurent, J, Lavanchy, J, Lienhardt-Nobbe, B, Locher, P, Losser, M, Lussman, R, Magliocca, A, Margarit, A, Martinez, A, Mauri, R, Mayor-Vazquez, E, Meier, J, Moret-Bochatay, M, Murrone, M, Naon, D, Neff, T, Novy, E, Petersen, L, Pugin, J, Ramelet, A, Rilinger, J, Rimensberger, P, Sepulcri, M, Shaikh, K, Sieber, M, Simonini, M, Spadaro, S, Sridharan, G, Stahl, K, Staudacher, D, Taboada-Fraga, X, Tellez, A, Urech, S, Vitale, G, Vizmanos-Lamotte, G, Welte, T, Zalba-Etayo, B, Zellweger, N, and Intensive Care

Subjects
Male, ARDS, Time Factors, medicine.medical_treatment, Old age, Critical Care and Intensive Care Medicine, law.invention, 0302 clinical medicine, law, Oxygen therapy, Noninvasive mechanical ventilation, Intubation, 030212 general & internal medicine, Hospital Mortality, Prospective Studies, Registries, Prospective cohort study, 610 Medicine & health, Unitats de cures intensives, Intensive care units, Medical emergencies. Critical care. Intensive care. First aid, Middle Aged, Intensive care unit, Intensive Care Units, Treatment Outcome, Vellesa, High flow oxygen therapy, Disease Progression, Female, Standard oxygen therapy, medicine.medical_specialty, Respiratory Therapy, Critical Illness, NO, 03 medical and health sciences, Intensive care, medicine, Humans, Invasive mechanical ventilation, Critically ill, Patient self-inflicted lung injury, Aged, Retrospective Studies, Mechanical ventilation, COVID-19/mortality, COVID-19/therapy, Critical Illness/mortality, Critical Illness/therapy, Respiratory Therapy/methods, Respiratory Therapy/statistics & numerical data, COVID-19, Respiratory support, business.industry, RC86-88.9, Research, Retrospective cohort study, medicine.disease, Malalts en estat crític, 030228 respiratory system, Emergency medicine, business
Abstract

Background Uncertainty about the optimal respiratory support strategies in critically ill COVID-19 patients is widespread. While the risks and benefits of noninvasive techniques versus early invasive mechanical ventilation (IMV) are intensely debated, actual evidence is lacking. We sought to assess the risks and benefits of different respiratory support strategies, employed in intensive care units during the first months of the COVID-19 pandemic on intubation and intensive care unit (ICU) mortality rates. Methods Subanalysis of a prospective, multinational registry of critically ill COVID-19 patients. Patients were subclassified into standard oxygen therapy ≥10 L/min (SOT), high-flow oxygen therapy (HFNC), noninvasive positive-pressure ventilation (NIV), and early IMV, according to the respiratory support strategy employed at the day of admission to ICU. Propensity score matching was performed to ensure comparability between groups. Results Initially, 1421 patients were assessed for possible study inclusion. Of these, 351 patients (85 SOT, 87 HFNC, 87 NIV, and 92 IMV) remained eligible for full analysis after propensity score matching. 55% of patients initially receiving noninvasive respiratory support required IMV. The intubation rate was lower in patients initially ventilated with HFNC and NIV compared to those who received SOT (SOT: 64%, HFNC: 52%, NIV: 49%, p = 0.025). Compared to the other respiratory support strategies, NIV was associated with a higher overall ICU mortality (SOT: 18%, HFNC: 20%, NIV: 37%, IMV: 25%, p = 0.016). Conclusion In this cohort of critically ill patients with COVID-19, a trial of HFNC appeared to be the most balanced initial respiratory support strategy, given the reduced intubation rate and comparable ICU mortality rate. Nonetheless, considering the uncertainty and stress associated with the COVID-19 pandemic, SOT and early IMV represented safe initial respiratory support strategies. The presented findings, in agreement with classic ARDS literature, suggest that NIV should be avoided whenever possible due to the elevated ICU mortality risk.

Published
2021

39. [Automatic load-distributing band CPR (AutoPulse™) in prone position, feasible?]

Author

Pietsch, U., Knapp, J., Wenzel, V., Lischke, V., and Albrecht, R.

Subjects
mental disorders, 610 Medicine & health
Abstract

BACKGROUND Due to SARS-CoV‑2 respiratory failure, prone positioning of patients with respiratory and hemodynamic instability has become a frequent intervention in intensive care units (ICUs), and even in patients undergoing transfer in an ambulance or helicopter. It has become increasingly important how to perform safe and effective CPR in prone position, achieving both an optimal outcome for the patient and optimal protection of staff from infection. MATERIALS AND METHODS We conducted feasibility tests to assess the effects of CPR with an automatic load-distributing band (AutoPulse™) in prone position and discussed different aspects of mechanical chest compression (mCPR) in prone position. RESULTS In supine position, AutoPulse™ generated a constant pressure depth of 3cm at a frequency of 84/min. In prone position, AutoPulse™ generated a constant pressure depth of 2.6cm at a frequency of 84/min. CONCLUSION We found mCPR to be feasible in manikins in both prone and supine positions.

Published
2020
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40. ESUO - The European Synchrotron and FEL User Organisation: Aims and activities

Author

Aksoy, A., Arčon, I., Arikan, P., Bittencourt, C., Boscherini, F., Braz Fernandes, F. M., Brooks, N., Casu, B., Cianci, M., Feiters, M., Froideval, A., Granroth, S., Gross, S., Gutt, C., Hase, T., Jablonska, K., Jergel, M., Karsli, Ö., Khan, A., Kirm, M., Kokkinidis, M., Kövér, L., Kuzmin, A., Landau, M., Larsen, H. B., Lechner, R. T., Le-Hir, R., Logan, D. T., López, O., Lorentz, K., Mariani, C., Marinkovic, B., McGuinness, C., Meedom Nielsen, M., Mičetić, M., Mikulík, P., Padežnik Gomilšek, J., Petukhov, A., Pietsch, U., Renault, L., Russell, A., Shivachev, B., Sobierajski, R., Stangl, J., Thissen, R., Tromp, M., Vankó, G., Witkowska, A., Blasetti, C., Freire Anselmo, A. S., Grobosch, M., Helm, M., Schramm, B., Schultheiss, K., and Vollmer, A.

Abstract

The European Synchrotron and free-electron laser User Organisation (ESUO) represents about 22.000 users from 30 European member states and associated countries. Each country is represented within ESUO by one up to four national delegate(s), depending on the size of the user community in the respective country. The ESUO aims and activities are shown in this poster.

Published
2020

44. Band bending at the heterointerface of GaAs/InAs core/shell nanowires monitored by synchrotron X-ray photoelectron spectroscopy.

Author

Khanbabaee, B., Bussone, G., Knutsson, J. V., Geijselaers, I., Pryor, C. E., Rieger, T., Demarina, N., Grützmacher, D., Lepsa, M. I., Timm, R., and Pietsch, U.

Subjects
NANOWIRES, GALLIUM arsenide, INDIUM arsenide, HETEROSTRUCTURES, ENERGY bands, X-ray photoelectron spectroscopy
Abstract

Unique electronic properties of semiconductor heterostructured nanowires make them useful for future nano-electronic devices. Here, we present a study of the band bending effect at the heterointerface of GaAs/InAs core/shell nanowires by means of synchrotron based X-ray photoelectron spectroscopy. Different Ga, In, and As core-levels of the nanowire constituents have been monitored prior to and after cleaning from native oxides. The cleaning process mainly affected the Asoxides and was accompanied by an energy shift of the core-level spectra towards lower binding energy, suggesting that the As-oxides turn the nanowire surfaces to n-type. After cleaning, both As and Ga core-levels revealed an energy shift of about -0.3 eV for core/shell compared to core reference nanowires. With respect to depth dependence and in agreement with calculated strain distribution and electron quantum confinement, the observed energy shift is interpreted by band bending of core-levels at the heterointerface between the GaAs nanowire core and the InAs shell. [ABSTRACT FROM AUTHOR]

Published
2016
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