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1. Employing Channel Probing to Derive End-of-Life Service Margins for Optical Spectrum Services. To appear in OPTICA Journal of Optical Communications and Networking

Author

Kaeval, K., Slyne, F., Troia, S., Kenny, E., Große, K., Griesser, H., Kilper, D. C., Ruffini, M., Pedreno-Manresa, J-J, Patri, S. K., and Jervan, G.

Subjects
Computer Science - Networking and Internet Architecture
Abstract

Optical Spectrum as a Service (OSaaS) spanning over multiple transparent optical network domains, can significantly reduce the investment and operational costs of the end-to-end service. Based on the black-link approach, these services are empowered by reconfigurable transceivers and the emerging disaggregation trend in optical transport networks. This work investigates the accuracy aspects of the channel probing method used in Generalized Signal to Noise Ratio (GSNR)-based OSaaS characterization in terrestrial brownfield systems. OSaaS service margins to accommodate impacts from enabling neighboring channels and end-of-life channel loads are experimentally derived in a systematic lab study carried out in the Open Ireland testbed. The applicability of the lab-derived margins is then verified in the HEAnet production network using a 400 GHz wide OSaaS. Finally, the probing accuracy is tested by depleting the GSNR margin through power adjustments utilizing the same 400 GHz OSaaS in the HEAnet live network. A minimum of 0.92 dB and 1.46 dB of service margin allocation is recommended to accommodate the impacts of enabling neighboring channels and end-of-life channel loads. Further 0.6 dB of GSNR margin should be allocated to compensate for probing inaccuracies.

Published
2023

2. Ignition and propagation of nanosecond pulsed discharges in distilled water -- negative vs. positive polarity applied to a pin electrode

Author

Grosse, K., Falke, M., and von Keudell, A.

Subjects
Physics - Plasma Physics
Abstract

Nanosecond plasmas in liquids are being used for water treatment, electrolysis or biomedical applications. The exact nature of these very dynamic plasmas and most important their ignition physics are strongly debated. The ignition itself may be explained by two competing hypothesis: (i) ignition via field effects or (ii) via electron multiplication in nanovoids. Both hypothesis are supported by theory, but experimental data are very sparse due to the difficulty to monitor the very fast processes in space and time. In this paper, we are using fast camera measurements and fast emission spectroscopy of nanosecond plasmas in water applying a positive and a negative polarity to a sharp tungsten electrode. It is shown that plasma ignition is dominated by field effects at the electrode-liquid interface either as field ionization for positive polarity or as field emission for negative polarity. This leads to a hot tungsten surface at a temperature of 7000 K for positive polarity, whereas the surface temperature is much lower for the negative polarity. At ignition, the electron density reaches 4 $\cdot$ 10$^{25}$ m$^{-3}$ for positive and only 2 $\cdot$ 10$^{25}$ m$^{-3}$ for the negative polarity. At the same time, the emission of the \Ha~light for the positive polarity is 4 times higher than that for the negative polarity. During plasma propagation, the electron densities are almost identical of the order of a 1 to 2 $\cdot$ 10$^{25}$ m$^{-3}$ and decay after the end of the pulse over 15 ns. It is concluded that plasma propagation is governed by field effects in a low density region that is created either by nanovoids or by density fluctuation in super critical water surrounding the electrode that is created by the pressure at the moment of plasma ignition.

Published
2021
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3. Adequate versus deep response to ursodeoxycholic acid in primary biliary cholangitis: To what extent and under what conditions is normal alkaline phosphatase level associated with complication-free survival gain?

Author

Corpechot, C, Lemoinne, S, Soret, P, Hansen, B, Hirschfield, G, Gulamhusein, A, Montano-Loza, A, Lytvyak, E, Pares, A, Olivas, I, Eaton, J, Osman, K, Schramm, C, Sebode, M, Lohse, A, Dalekos, G, Gatselis, N, Nevens, F, Cazzagon, N, Zago, A, Russo, F, Floreani, A, Abbas, N, Trivedi, P, Thorburn, D, Saffioti, F, Barkai, L, Roccarina, D, Calvaruso, V, Fichera, A, Delamarre, A, Sobenko, N, Villamil, A, Medina-Morales, E, Bonder, A, Patwardhan, V, Rigamonti, C, Carbone, M, Invernizzi, P, Cristoferi, L, Van Der Meer, A, De Veer, R, Zigmond, E, Yehezkel, E, Kremer, A, Deibel, A, Bruns, T, Grosse, K, Wetten, A, Dyson, J, Jones, D, Dumortier, J, Pageaux, G, De Ledinghen, V, Chazouilleres, O, Carrat, F, Corpechot C., Lemoinne S., Soret P. -A., Hansen B., Hirschfield G., Gulamhusein A., Montano-Loza A. J., Lytvyak E., Pares A., Olivas I., Eaton J. E., Osman K. T., Schramm C., Sebode M., Lohse A. W., Dalekos G., Gatselis N., Nevens F., Cazzagon N., Zago A., Russo F. P., Floreani A., Abbas N., Trivedi P., Thorburn D., Saffioti F., Barkai L., Roccarina D., Calvaruso V., Fichera A., Delamarre A., Sobenko N., Villamil A. M., Medina-Morales E., Bonder A., Patwardhan V., Rigamonti C., Carbone M., Invernizzi P., Cristoferi L., Van Der Meer A., De Veer R., Zigmond E., Yehezkel E., Kremer A. E., Deibel A., Bruns T., Grosse K., Wetten A., Dyson J. K., Jones D., Dumortier J., Pageaux G. -P., De Ledinghen V., Chazouilleres O., Carrat F., Corpechot, C, Lemoinne, S, Soret, P, Hansen, B, Hirschfield, G, Gulamhusein, A, Montano-Loza, A, Lytvyak, E, Pares, A, Olivas, I, Eaton, J, Osman, K, Schramm, C, Sebode, M, Lohse, A, Dalekos, G, Gatselis, N, Nevens, F, Cazzagon, N, Zago, A, Russo, F, Floreani, A, Abbas, N, Trivedi, P, Thorburn, D, Saffioti, F, Barkai, L, Roccarina, D, Calvaruso, V, Fichera, A, Delamarre, A, Sobenko, N, Villamil, A, Medina-Morales, E, Bonder, A, Patwardhan, V, Rigamonti, C, Carbone, M, Invernizzi, P, Cristoferi, L, Van Der Meer, A, De Veer, R, Zigmond, E, Yehezkel, E, Kremer, A, Deibel, A, Bruns, T, Grosse, K, Wetten, A, Dyson, J, Jones, D, Dumortier, J, Pageaux, G, De Ledinghen, V, Chazouilleres, O, Carrat, F, Corpechot C., Lemoinne S., Soret P. -A., Hansen B., Hirschfield G., Gulamhusein A., Montano-Loza A. J., Lytvyak E., Pares A., Olivas I., Eaton J. E., Osman K. T., Schramm C., Sebode M., Lohse A. W., Dalekos G., Gatselis N., Nevens F., Cazzagon N., Zago A., Russo F. P., Floreani A., Abbas N., Trivedi P., Thorburn D., Saffioti F., Barkai L., Roccarina D., Calvaruso V., Fichera A., Delamarre A., Sobenko N., Villamil A. M., Medina-Morales E., Bonder A., Patwardhan V., Rigamonti C., Carbone M., Invernizzi P., Cristoferi L., Van Der Meer A., De Veer R., Zigmond E., Yehezkel E., Kremer A. E., Deibel A., Bruns T., Grosse K., Wetten A., Dyson J. K., Jones D., Dumortier J., Pageaux G. -P., De Ledinghen V., Chazouilleres O., and Carrat F.

Abstract

Background and Aims: Normal alkaline phosphatase (ALP) levels in ursodeoxycholic acid (UDCA)-treated patients with primary biliary cholangitis (PBC) are associated with better long-term outcome. However, second-line therapies are currently recommended only when ALP levels remain above 1.5 times the upper limit of normal (×ULN) after 12-month UDCA. We assessed whether, in patients considered good responders to UDCA, normal ALP levels were associated with significant survival gains. Approach and Results: We performed a retrospective cohort study of 1047 patients with PBC who attained an adequate response to UDCA according to Paris-2 criteria. Time to liver-related complications, liver transplantation, or death was assessed using adjusted restricted mean survival time (RMST) analysis. The overall incidence rate of events was 17.0 (95% CI: 13.7-21.1) per 1000 out of 4763.2 patient-years. On the whole population, normal serum ALP values (but not normal gamma-glutamyl transpeptidase (GGT), alanine aminotransferase (ALT), or aspartate aminotransferase (AST); or total bilirubin < 0.6 ×ULN) were associated with a significant absolute complication-free survival gain at 10 years (mean 7.6 months, 95% CI: 2.7 - 12.6 mo.; p = 0.003). In subgroup analysis, this association was significant in patients with a liver stiffness measurement ≥ 10 kPa and/or age ≤ 62 years, with a 10-year absolute complication-free survival gain of 52.8 months (95% CI: 45.7-59.9, p < 0.001) when these 2 conditions were met. Conclusions: PBC patients with an adequate response to UDCA and persistent ALP elevation between 1.1 and 1.5 ×ULN, particularly those with advanced fibrosis and/or who are sufficiently young, remain at risk of poor outcome. Further therapeutic efforts should be considered for these patients.

Published
2024

7. Ignition and propagation of nanosecond pulsed plasmas in distilled water—Negative vs positive polarity applied to a pin electrode.

Author

Grosse, K., Falke, M., and von Keudell, A.

Subjects
TUNGSTEN electrodes, ELECTRON density, INDUCTIVE effect, ELECTRIC fields, ELECTRON tunneling, FIELD emission, SUPERCRITICAL water, DISTILLED water
Abstract

Nanosecond plasmas in liquids are being used for water treatment, electrolysis, or biomedical applications. The exact nature of these very dynamic plasmas and, most importantly, their ignition physics are strongly debated. The ignition itself may be explained by two competing hypotheses: ignition in water may occur (i) via field effects at the tip of the electrode followed by tunneling of electrons in between water molecules causing field ionization or (ii) via gaseous processes of electron multiplication in nanovoids that are created from liquid ruptures due to the strong electric field gradients. Both hypotheses are supported by theory, but experimental data are very sparse due to the difficulty in monitoring the very fast processes in space and time. In this paper, we analyze nanosecond plasmas in water that are created by applying a positive and a negative polarity to a sharp tungsten electrode. The main diagnostics are fast camera measurements and fast emission spectroscopy. It is shown that plasma ignition is dominated by field effects at the electrode–liquid interface either as field ionization for positive polarity or as field emission for negative polarity. This leads to a hot tungsten surface at a temperature of 7000 K for positive polarity, whereas the surface temperature is much lower for negative polarity. At ignition, the electron density reaches 4 × 10 25 m − 3 for the positive and 2 × 10 25 m − 3 for the negative polarity. At the same time, the emission of the H α light for the positive polarity is four times higher than that for the negative polarity. During plasma propagation, the electron densities are almost identical of the order of 1– 2 × 10 25 m − 3 followed by a decay after the end of the pulse over 15 ns. It is concluded that plasma propagation is governed by field effects in a low density region that is created either by nanovoids or by density fluctuations in supercritical water surrounding the electrode that is created by the pressure and temperature at the moment of plasma ignition. [ABSTRACT FROM AUTHOR]

Published
2021
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10. Inflammatory changes in the hippocampus after experimental traumatic brain injury in a rat model

Author

Große, K, Grutza, M, Walter, J, Heene, S, Zheng, G, Skutella, T, Unterberg, AW, Zweckberger, K, and Younsi, A

Subjects
ddc: 610, Medicine and health
Abstract

Objective: Traumatic brain injury (TBI) is a leading cause of death worldwide. After the primary injury, a cascade of secondary injury processes is initiated, including a complex inflammatory reaction. As a critical and vulnerable brain region, the hippocampus is commonly affected by such neuroinflammation. [for full text, please go to the a.m. URL]

Published
2022
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12. Liver stiffness measurement by vibration-controlled transient elastography improves outcome prediction in primary biliary cholangitis

Author

Corpechot, C, Carrat, F, Gaouar, F, Chau, F, Hirschfield, G, Gulamhusein, A, Montano-Loza, A, Lytvyak, E, Schramm, C, Pares, A, Olivas, I, Eaton, J, Osman, K, Dalekos, G, Gatselis, N, Nevens, F, Cazzagon, N, Zago, A, Russo, F, Abbas, N, Trivedi, P, Thorburn, D, Saffioti, F, Barkai, L, Roccarina, D, Calvaruso, V, Fichera, A, Delamarre, A, Medina-Morales, E, Bonder, A, Patwardhan, V, Rigamonti, C, Carbone, M, Invernizzi, P, Cristoferi, L, van der Meer, A, de Veer, R, Zigmond, E, Yehezkel, E, Kremer, A, Deibel, A, Dumortier, J, Bruns, T, Große, K, Pageaux, G, Wetten, A, Dyson, J, Jones, D, Chazouillères, O, Hansen, B, de Lédinghen, V, Corpechot, Christophe, Carrat, Fabrice, Gaouar, Farid, Chau, Frederic, Hirschfield, Gideon, Gulamhusein, Aliya, Montano-Loza, Aldo J, Lytvyak, Ellina, Schramm, Christoph, Pares, Albert, Olivas, Ignasi, Eaton, John E, Osman, Karim T, Dalekos, George, Gatselis, Nikolaos, Nevens, Frederik, Cazzagon, Nora, Zago, Alessandra, Russo, Francesco Paolo, Abbas, Nadir, Trivedi, Palak, Thorburn, Douglas, Saffioti, Francesca, Barkai, Laszlo, Roccarina, Davide, Calvaruso, Vicenza, Fichera, Anna, Delamarre, Adèle, Medina-Morales, Esli, Bonder, Alan, Patwardhan, Vilas, Rigamonti, Cristina, Carbone, Marco, Invernizzi, Pietro, Cristoferi, Laura, van der Meer, Adriaan, de Veer, Rozanne, Zigmond, Ehud, Yehezkel, Eyal, Kremer, Andreas E, Deibel, Ansgar, Dumortier, Jérôme, Bruns, Tony, Große, Karsten, Pageaux, Georges-Philippe, Wetten, Aaron, Dyson, Jessica, Jones, David, Chazouillères, Olivier, Hansen, Bettina, de Lédinghen, Victor, Corpechot, C, Carrat, F, Gaouar, F, Chau, F, Hirschfield, G, Gulamhusein, A, Montano-Loza, A, Lytvyak, E, Schramm, C, Pares, A, Olivas, I, Eaton, J, Osman, K, Dalekos, G, Gatselis, N, Nevens, F, Cazzagon, N, Zago, A, Russo, F, Abbas, N, Trivedi, P, Thorburn, D, Saffioti, F, Barkai, L, Roccarina, D, Calvaruso, V, Fichera, A, Delamarre, A, Medina-Morales, E, Bonder, A, Patwardhan, V, Rigamonti, C, Carbone, M, Invernizzi, P, Cristoferi, L, van der Meer, A, de Veer, R, Zigmond, E, Yehezkel, E, Kremer, A, Deibel, A, Dumortier, J, Bruns, T, Große, K, Pageaux, G, Wetten, A, Dyson, J, Jones, D, Chazouillères, O, Hansen, B, de Lédinghen, V, Corpechot, Christophe, Carrat, Fabrice, Gaouar, Farid, Chau, Frederic, Hirschfield, Gideon, Gulamhusein, Aliya, Montano-Loza, Aldo J, Lytvyak, Ellina, Schramm, Christoph, Pares, Albert, Olivas, Ignasi, Eaton, John E, Osman, Karim T, Dalekos, George, Gatselis, Nikolaos, Nevens, Frederik, Cazzagon, Nora, Zago, Alessandra, Russo, Francesco Paolo, Abbas, Nadir, Trivedi, Palak, Thorburn, Douglas, Saffioti, Francesca, Barkai, Laszlo, Roccarina, Davide, Calvaruso, Vicenza, Fichera, Anna, Delamarre, Adèle, Medina-Morales, Esli, Bonder, Alan, Patwardhan, Vilas, Rigamonti, Cristina, Carbone, Marco, Invernizzi, Pietro, Cristoferi, Laura, van der Meer, Adriaan, de Veer, Rozanne, Zigmond, Ehud, Yehezkel, Eyal, Kremer, Andreas E, Deibel, Ansgar, Dumortier, Jérôme, Bruns, Tony, Große, Karsten, Pageaux, Georges-Philippe, Wetten, Aaron, Dyson, Jessica, Jones, David, Chazouillères, Olivier, Hansen, Bettina, and de Lédinghen, Victor

Abstract

Background & Aims: Liver stiffness measurement (LSM) by vibration-controlled transient elastography (VCTE) has been shown to predict outcomes of patients with primary biliary cholangitis (PBC) in small-size studies. We aimed to validate the prognostic value of LSM in a large cohort study. Methods: We performed an international, multicentre, retrospective follow-up study of 3,985 patients with PBC seen at 23 centres in 12 countries. Eligibility criteria included at least 1 reliable LSM by VCTE and a follow-up ≥ 1 year. Independent derivation (n = 2,740) and validation (n = 568) cohorts were built. The primary endpoint was time to poor clinical outcomes defined as liver-related complications, liver transplantation, or death. Hazard ratios (HRs) with CIs were determined using a time-dependent multivariable Cox regression analysis. Results: LSM was independently associated with poor clinical outcomes in the derivation (5,324 LSMs, mean follow-up 5.0 ± 3.1 years) and validation (1,470 LSMs, mean follow-up 5.0 ± 2.8 years) cohorts: adjusted HRs (95% CI) per additional kPa were 1.040 (1.026–1.054) and 1.042 (1.029–1.056), respectively (p <0.0001 for both). Adjusted C-statistics (95% CI) at baseline were 0.83 (0.79–0.87) and 0.92 (0.89–0.95), respectively. Between 5 and 30 kPa, the log-HR increased as a monotonic function of LSM. The predictive value of LSM was stable in time. LSM improved the prognostic ability of biochemical response criteria, fibrosis scores, and prognostic scores. The 8 kPa and 15 kPa cut-offs optimally separated low-, medium-, and high-risk groups. Forty percent of patients were at medium to high risk according to LSM. Conclusions: LSM by VCTE is a major, independent, validated predictor of PBC outcome. Its value as a surrogate endpoint for clinical benefit in PBC should be considered. Lay summary: Primary biliary cholangitis (PBC) is a chronic autoimmune disease, wherein the body's immune system mistakenly attacks the bile ducts. PBC progresses

Published
2022

24. Nanosecond pulsed discharges in distilled water-Part II: line emission and plasma propagation.

Author

Keudell, A von, Grosse, K, and Gathen, V Schulz-von der

Subjects
*BLACKBODY radiation, *CHEMICAL processes, *PLASMA gases, *ELECTRON density, *ELECTRON transport, *SPECTRAL line broadening
Abstract

Nanosecond plasmas in liquids can initiate chemical processes that are exploited in the fields of water treatment, electrolysis or biomedical applications. The understanding of these chemical processes relies on unraveling the dynamics of the variation of pressures, temperatures and species densities during the different stages of plasma ignition and plasma propagation as well as the conversion of the liquid into the plasma state and the gas phase. This is analyzed by monitoring the emission of nanosecond pulsed plasmas that are generated by high voltages of 20 kV and pulse lengths of 10 ns applied to a tungsten tip with 50 μm diameter immersed in water. The spectra are acquired with a temporal resolution of 2 ns and the emission pattern is modelled by a combination of black body radiation from the hot tungsten tip and the pronounced emission lines of the hydrogen Balmer series. The data indicate two contributions of the hydrogen line radiation that differ with respect to the degree of self-absorption. It is postulated that one contribution originates from a recombination region showing strong self absorption and one contribution from an ionization region showing very little self-absorption. The emission lines from the ionization region are evaluated assuming Stark broadening, that yielded electron densities up to 5 × 1025 m−3. The electron density evolution follows the same trend as the temporal evolution of the voltage applied to the tungsten tip. The propagation mechanism of the plasma is similar to that of a positive streamer in the gas phase, although in the liquid phase field effects such as electron transport by tunneling should play an important role. [ABSTRACT FROM AUTHOR]

Published
2020
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43. Publication fees for Open Access journals - work flows at Helmholtz Centres

Author

Reschke, E., Köhler, M., Wagner, A., Grosse, K., Reschke, E., Köhler, M., Wagner, A., and Grosse, K.

Abstract

Open Access is a new way of publishing. The presentation aims to show how the golden way of Open Access Publishing has to be funding. Based on the "Berlin Declaration to Knowledge in the Science and Humanities" and the "Agreement of the Assembly of Members" (assembly of the directors of the Helmholtz Centres) the Helmholtz Research Centres organized the publishing and funding process in different ways. The presentation shows 4 examples for it: DESY, Forschungszentrum Jülich, GSI Darmstadt and HZDR.

Published
2013

49. Heißgießen von drucklos gesintertem Siliziumcarbid - Herstellung der Heißgießschlicker

Author

Lenk, R., Kriwoschepow, A.F., Grosse, K., and Publica

Subjects
carbon black, silicon carbide, ceramic, Ruß, Heißgießen, processing, Siliziumcarbid, hot moulding, Keramik
Abstract

Based on the results of the investigation of stabilization of carbon black, boron and silicon carbide both in polar and apolar solvents several ways for adding the sinteractivating agents are possible. The preparation in water can be carried out either by homogenization of the separate solid-state compounds with negative surface charge or by heterocoagulation. In this case postive charged carbon particles coagulate to the negative charged SiC surface. The heterocoagulation can be detected by electrokinetic measurement at the raw materials suspension and the prepared suspensions of mixtures. The powder processing was carried out by separate wet homogenization of SiC and boron in a ball mill, producing the carbon black suspension in a solution of Alkylbenzyldimethyl- ammoniumchloride in water by ultrasonic treatment, mixing the suspensions and drying. To prepare the thermoplastic slip, the binder consisting paraffin, bees wax and diethanolamide of fatty acids was heated in a ball mill up to 100 o degree. Then the dried and heated ceramic powder was stirred into the melted binder. The prepared thermoplastic slip composition could be used for moulding immediately as well as cooled and stored.

Published
1995

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