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668 results on '"Ambrozic, A."'

4. CORTEX experiments – Part I: Modulation campaigns in AKR-2 & CROCUS for the validation of neutron noise codes

Author

Lamirand, Vincent, Knospe, Alexander, Ambrožič, Klemen, Hübner, Sebastian, Lange, Carsten, Pakari, Oskari, Vitullo, Fanny, Rais, Adolfo, Pohlus, Joachim, Paquee, Uwe, Pohl, Christoph, Weiss, Nicolas, Frajtag, Pavel, Godat, Daniel, Mylonakis, Antonios, Laureau, Axel, Ligonnet, Thomas, Hursin, Mathieu, Perret, Grégory, and Pautz, Andreas

Published
2025
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5. Deep learning models for automatic tumor segmentation and total tumor volume assessment in patients with colorectal liver metastases

Author

Nina J. Wesdorp, J. Michiel Zeeuw, Sam C. J. Postma, Joran Roor, Jan Hein T. M. van Waesberghe, Janneke E. van den Bergh, Irene M. Nota, Shira Moos, Ruby Kemna, Fijoy Vadakkumpadan, Courtney Ambrozic, Susan van Dieren, Martinus J. van Amerongen, Thiery Chapelle, Marc R. W. Engelbrecht, Michael F. Gerhards, Dirk Grunhagen, Thomas M. van Gulik, John J. Hermans, Koert P. de Jong, Joost M. Klaase, Mike S. L. Liem, Krijn P. van Lienden, I. Quintus Molenaar, Gijs A. Patijn, Arjen M. Rijken, Theo M. Ruers, Cornelis Verhoef, Johannes H. W. de Wilt, Henk A. Marquering, Jaap Stoker, Rutger-Jan Swijnenburg, Cornelis J. A. Punt, Joost Huiskens, and Geert Kazemier

Subjects
Artificial intelligence, Deep learning, Colorectal cancer, Liver neoplasms, Tomography (x-ray computed), Medical physics. Medical radiology. Nuclear medicine, R895-920
Abstract

Abstract Background We developed models for tumor segmentation to automate the assessment of total tumor volume (TTV) in patients with colorectal liver metastases (CRLM). Methods In this prospective cohort study, pre- and post-systemic treatment computed tomography (CT) scans of 259 patients with initially unresectable CRLM of the CAIRO5 trial (NCT02162563) were included. In total, 595 CT scans comprising 8,959 CRLM were divided into training (73%), validation (6.5%), and test sets (21%). Deep learning models were trained with ground truth segmentations of the liver and CRLM. TTV was calculated based on the CRLM segmentations. An external validation cohort was included, comprising 72 preoperative CT scans of patients with 112 resectable CRLM. Image segmentation evaluation metrics and intraclass correlation coefficient (ICC) were calculated. Results In the test set (122 CT scans), the autosegmentation models showed a global Dice similarity coefficient (DSC) of 0.96 (liver) and 0.86 (CRLM). The corresponding median per-case DSC was 0.96 (interquartile range [IQR] 0.95–0.96) and 0.80 (IQR 0.67–0.87). For tumor segmentation, the intersection-over-union, precision, and recall were 0.75, 0.89, and 0.84, respectively. An excellent agreement was observed between the reference and automatically computed TTV for the test set (ICC 0.98) and external validation cohort (ICC 0.98). In the external validation, the global DSC was 0.82 and the median per-case DSC was 0.60 (IQR 0.29–0.76) for tumor segmentation. Conclusions Deep learning autosegmentation models were able to segment the liver and CRLM automatically and accurately in patients with initially unresectable CRLM, enabling automatic TTV assessment in such patients. Relevance statement Automatic segmentation enables the assessment of total tumor volume in patients with colorectal liver metastases, with a high potential of decreasing radiologist’s workload and increasing accuracy and consistency. Key points • Tumor response evaluation is time-consuming, manually performed, and ignores total tumor volume. • Automatic models can accurately segment tumors in patients with colorectal liver metastases. • Total tumor volume can be accurately calculated based on automatic segmentations. Graphical Abstract

Published
2023
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12. Deep learning models for automatic tumor segmentation and total tumor volume assessment in patients with colorectal liver metastases

Author

Wesdorp, Nina J., Zeeuw, J. Michiel, Postma, Sam C. J., Roor, Joran, van Waesberghe, Jan Hein T. M., van den Bergh, Janneke E., Nota, Irene M., Moos, Shira, Kemna, Ruby, Vadakkumpadan, Fijoy, Ambrozic, Courtney, van Dieren, Susan, van Amerongen, Martinus J., Chapelle, Thiery, Engelbrecht, Marc R. W., Gerhards, Michael F., Grunhagen, Dirk, van Gulik, Thomas M., Hermans, John J., de Jong, Koert P., Klaase, Joost M., Liem, Mike S. L., van Lienden, Krijn P., Molenaar, I. Quintus, Patijn, Gijs A., Rijken, Arjen M., Ruers, Theo M., Verhoef, Cornelis, de Wilt, Johannes H. W., Marquering, Henk A., Stoker, Jaap, Swijnenburg, Rutger-Jan, Punt, Cornelis J. A., Huiskens, Joost, and Kazemier, Geert

Published
2023
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14. Overview of recent advancements in IFMIF-DONES neutronics activities

Author

Qiu, Y., Ansorge, M., Álvarez, I., Ambrožič, K., Berry, T., Bieńkowska, B., Chohan, H., Čufar, A., Dworak, D., Dezsi, T., Eade, T., García, J., Jimenez-Rey, D., Lengar, I., Lopez-Revelles, A.J., Lopez, V., Mendoza, E., Mota, F., Martinez-Echevarria, M.J., Ogando, F., Park, J., Piotrowski, T., Serikov, A., Stankunas, G., Tidikas, A., Tracz, G., Žerovnik, G., Arbeiter, F., Arranz, F., Becerril, S., Cara, P., Bernardi, D., Castellanos, J., Gutiérrez, J., Ibarra, A., Królas, W., Maestre, J., Martín-Fuertes, F., Marugán, J.C., Micciché, G., Martínez-Serrano, J., Nitti, F.S., Podadera, I., Wiącek, U., and Fischer, U.

Published
2024
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16. Geometric Enhancement of the Cadastre of Underground Utility Networks

Author

Tuno, Nedim, Topoljak, Jusuf, Mulahusić, Admir, Đidelija, Muamer, Kulo, Nedim, Ambrožič, Tomaž, Kacprzyk, Janusz, Series Editor, Gomide, Fernando, Advisory Editor, Kaynak, Okyay, Advisory Editor, Liu, Derong, Advisory Editor, Pedrycz, Witold, Advisory Editor, Polycarpou, Marios M., Advisory Editor, Rudas, Imre J., Advisory Editor, Wang, Jun, Advisory Editor, Ademović, Naida, editor, Kevrić, Jasmin, editor, and Akšamija, Zlatan, editor

Published
2023
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17. Silicon carbide diodes for neutron detection

Author

Coutinho, José, Torres, Vitor J. B., Capan, Ivana, Brodar, Tomislav, Ereš, Zoran, Bernat, Robert, Radulović, Vladimir, Ambrožič, Klemen, Snoj, Luka, Pastuović, Željko, Sarbutt, Adam, Ohshima, Takeshi, Yamazaki, Yuichi, and Makino, Takahiro

Subjects
Physics - Instrumentation and Detectors, Condensed Matter - Materials Science
Abstract

In the last two decades we have assisted to a rush towards finding a He3-replacing technology capable of detecting neutrons emitted from fissile isotopes. The demand stems from applications like nuclear war-head screening or preventing illicit traffic of radiological materials. Semiconductor detectors stand among the stronger contenders, particularly those based on materials possessing a wide band gap like silicon carbide. We review the workings of SiC-based neutron detectors, along with several issues related to material properties, device fabrication and testing. The paper summarizes the experimental and theoretical work carried out within the E-SiCure project, co-funded by the NATO SPS Programme. Among the achievements, we have the development of successful Schottky barrier based detectors and the identification of the main carrier life-time-limiting defects in the SiC active areas, either already present in pristine devices or introduced upon exposure to radiation fields. The physical processes involved in neutron detection are described. Material properties as well as issues related to epitaxial growth and device fabrication are addressed. The presence of defects in as-grown material, as well as those introduced by ionizing radiation are reported. We finally describe several experiments carried out at the Jozef Stefan Institute TRIGA Mark II reactor (Ljubljana, Slovenia), where a set of SiC-based neutron detectors were tested, some of which being equipped with a thermal neutron converter layer. We show that despite the existence of large room for improvement, Schottky barrier diodes based on state-of-the-art 4H-SiC are closing the gap regarding the sensitivity offered by gas-based and that of semiconductor detectors.

Published
2020
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28. Stator Current Spectral Content of Inverter-Fed Cage Rotor Induction Motor

Author

Gojko Joksimovic, Peter Zajec, Alberto Tessarolo, Vanja Ambrozic, and Andraz Rihar

Subjects
Amplitude modulation, frequency modulation, induction motors, pulse width modulation, power converter harmonics, Electrical engineering. Electronics. Nuclear engineering, TK1-9971
Abstract

The paper analyzes the influence of the number of rotor bars on the stator current spectral content in a three-phase cage induction motor fed by a pulse-width modulated (PWM) inverter. It is shown that each of the higher-order time harmonics in the supply voltage produces space harmonics in a rotating magnetic flux density wave, which results in induced rotor slot harmonics (RSHs) in the stator current spectrum. The conditions for the existence of these space harmonics are identical to those applying to a mains-fed motor. In other words, the number of rotor bars of a mains-fed motor yielding an RSH-free stator current spectrum produces the same stator current spectrum even in case the motor is inverter-fed. Additionally, to minimize the adverse effects of RSHs in the stator current spectrum, one must consider not only the number of rotor bars, but also its relationship with the frequency modulation ratio of the PWM inverter. Analytical predictions are presented to illustrate these results supported both by numerical simulations of the induction motor modelled through the winding function theory and experimentally taking the case a two-pole cage induction machine as a case study.

Published
2022
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33. Silicon carbide diodes for neutron detection

Author

Coutinho, José, Torres, Vitor J.B., Capan, Ivana, Brodar, Tomislav, Ereš, Zoran, Bernat, Robert, Radulović, Vladimir, Ambrožič, Klemen, Snoj, Luka, Pastuović, Željko, Sarbutt, Adam, Ohshima, Takeshi, Yamazaki, Yuichi, and Makino, Takahiro

Published
2021
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35. Correlation between cerebral biomarkers and optic nerve sheath diameter in patients with severe preeclampsia

Author

Gabrijela Brzan Simenc, Jana Ambrozic, Josko Osredkar, Ksenija Gersak, and Miha Lucovnik

Subjects
neuron-specific enolase, ocular ultrasonography, optic nerve sheath diameter preeclampsia, s100b, Gynecology and obstetrics, RG1-991
Abstract

Objective: To examine the correlation between plasma cerebral biomarkers (S100B and neuron-specific enolase (NSE)) and ultrasonographic optic-nerve-sheath-diameter (ONSD) in preeclampsia. Methods: Thirty preeclampsia patients and 27 controls were included. Mann-Whitney-U test was used for comparison of S100B, NSE, and ONSD in preeclampsia vs. controls. Kendall’s tau was used to assess the correlation between biomarkers and ONSD (p

Published
2021
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43. A green approach toward epoxy-benzoxazine copolymers with shape-memory ability

Author

R. Ambrozic, A. Rucigaj, and M. Krajnc

Subjects
smart polymers, shape memory materials, bio-benzoxazine, epoxy, Materials of engineering and construction. Mechanics of materials, TA401-492, Chemical technology, TP1-1185
Abstract

In the frame of green-based chemistry, advanced shape memory polymers are designed from benzoxazine (RSBOX) and epoxy (R-EP) resins basing on potential natural raw materials, such as resorcinol and stearylamine. Thermal curing, investigated by differential scanning calorimetry, shows several overlapping peaks suggesting a complex curing mechanism. Dynamic mechanical analysis of cured RS-BOX/R-EP copolymers demonstrates an increase in the glass temperature and narrower glass transition by the increase of the RS-BOX ratio. In contrast, crosslinking density increases with higher epoxy resin content. All investigated materials possess one-way dual shape memory ability triggered by glass transition temperature with excellent shape fixity, while the shape recovery values ranged between 95 and 100%. The duration of the recovery process is significantly influenced by the RS-BOX amount. Additionally, the mechanical and shape memory properties of fully bio-based SMPs might be suitably tailored for advanced applications by merely varying the initial composition.

Published
2020
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46. Depth Profile of Optically Recorded Patterns in Light-Sensitive Liquid Crystal Elastomers

Author

Gregorc, Marko, Zalar, Boštjan, Domenici, Valentina, Ambrožič, Gabriela, Drevenšek-Olenik, Irena, Fally, Martin, and Čopič, Martin

Subjects
Physics - Optics
Abstract

We investigated nonlinear absorption and photobleaching processes in a liquid crystal elastomer (LCE) doped with light-sensitive azobenzene moiety. A conventional one-dimensional holographic grating was recorded in the material with the use of two crossed UV laser beams and the angular dependence of the diffraction efficiency in the vicinity of the Bragg peak was analyzed. These measurements gave information on the depth to which trans to cis isomerisation had progressed into the sample as a function of the UV irradiation time. Using a numerical model that takes into account the propagation of writing beams and rate equations for the local concentration of the absorbing trans conformer, we computed the expected spatial distribution of the trans and cis conformers and the shape of the corresponding Bragg diffraction peak for different irradiation doses. Due to residual absorption of the cis conformers the depth of the recording progresses logarithmically with time and is limited by the thermal relaxation from the cis to trans conformation., Comment: 19 pages (incl. figs), 6 figures

Published
2011
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48. Development of a New International Antiphospholipid Syndrome Classification Criteria Phase I/II Report: Generation and Reduction of Candidate Criteria

Author

Barbhaiya, Medha, Zuily, Stephane, Ahmadzadeh, Yasaman, Amigo, Mary‐Carmen, Avcin, Tadej, Bertolaccini, Maria Laura, Branch, D. Ware, de Jesus, Guilherme, Devreese, Katrien M. J., Frances, Camille, Garcia, David, Guillemin, Francis, Levine, Steven R., Levy, Roger A., Lockshin, Michael D., Ortel, Thomas L., Seshan, Surya V., Tektonidou, Maria, Wahl, Denis, Willis, Rohan, Naden, Ray, Costenbader, Karen, Erkan, Doruk, Agmon‐Levin, Nancy, Aguilar, Cassyanne, Alba, Paula, Alpan, Oral, Ambrozic, Ales, Amoura, Zahir, Andrade, Danieli, Andrade, Luis, Appenzeller, Simone, Esen, Bahar Artim, Atsumi, Tatsuya, Berkun, Yackov, Cabral, Antonio, Canaud, Guillaume, Cervera, Ricard, Chen, Pojen, Chighizola, Cecilia, Cimaz, Rolando, Cohen, Hannah, Costedoat‐Chalumeau, Nathalie, Crowther, Mark, Cuadrado, Maria Jose, de Groot, Philip G., de Moerloose, Philippe, Derksen, Ronald, Diz‐Kucukkaya, Reyhan, Dörner, Thomas, Fortin, Paul, Giannakopoulos, Bill, Gómez‐Puerta, Jose A., Gonzalez, Emilio B., Inanc, Murat, Kenet, Gili, Khamashta, Munther, Kriegel, Martin, Krilis, Steven, Laskin, Carl, Massicotte, Patti, McCarty, Gale, Meroni, Pier Luigi, Mikdashi, Jamal, Myones, Barry, Pengo, Vittorio, Petri, Michelle, Roubey, Robert, Sammaritano, Lisa, Sanna, Giovanni, Sciascia, Savino, Signorelli, Flavio, Soybilgic, Arzu, Tincani, Angela, Woller, Scott, and Yelnik, Cécile

Published
2021
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49. Uporabnost novejših metod deformacije miokarda pri vsakdanji ultrazvočni preiskavi srca

Author

Marta Cvijič, Jana Ambrozic, Andreja Čerček Černe, Mojca Bervar, and Janez Toplišek

Subjects
ehokardiografija, deformacija, GLS, metoda sledenja ultrazvočnega vzorca, Medicine
Abstract

Slikovna preiskava deformacije miokarda s sledenjem ultrazvočnega vzorca (ang. speckle tracking imaging-STI) je novejša metoda v ehokardiografiji, ki omogoča vpogled v mehaniko delovanja srčne mišice in se vse pogosteje uporablja pri vsakdanjem kliničnem delu. S to metodo se je uveljavil tudi nov globalni kazalec deformacije levega prekata v longitudinalni smeri (angl. global longitudinal strain-GLS), ki se je izkazal kot bolj občutljiv kazalec za odkrivanje zgodnje okvare miokarda kot klasični ehokardiografski kazalci sistolične funkcije. Kazalci deformacije imajo tako diagnostično kot prognostično vrednost pri številnih bolezenskih stanjih. Značilne spremembe, ki jih lahko zaznamo s STI pri ishemični bolezni srca so znižanje deformacije v sistoli, raztezanje miokarda v zgodnji sistoli in skrajšanje miokarda po koncu sistole. Metoda STI nam je v pomoč pri odkrivanju zgodnje okvare sistolične funkcije pri bolnikih s hipertrofijo miokarda in pri razlikovanju vzrokov hipertrofij. S STI lahko prepoznamo subklinično okvaro miokarda po kemoterapiji, zato ji dajejo evropska priporočila prednost pred klasičnimi ehokardiografskimi kazalci pri nadaljnjem kliničnem odločanju. Pri asimptomatičnih bolnikih z zmerno do hudo boleznijo srčnih zaklopk znižane vrednosti GLS kažejo na prikrito okvaro miokarda in napovedujejo večje tveganje za po-operativne zaplete. Pri bolnikih z miokarditisom s STI zaznamo znižane vrednosti segmentne deformacije in odražajo fokalno prizadetost levega prekata. Prav tako pa kazalniki deformacije miokarda tudi dobro napovedujejo uspešnost zdravljenja pri bolnikih z resinhronizacijskim spodbujevalnikom. V prispevku želimo predstaviti osnove analizo GLS po posameznih korakih, ki veljajo ne glede na vrsto ultrazvočnega aparata ali programske opreme, ter predstaviti primere uporabe STI pri posameznih bolezenskih stanjih, za katere obstaja največ dokazov klinične uporabnosti.

Published
2019
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