TY - JOUR A1 - Kotliar, Konstantin A1 - Ortner, Marion A1 - Conradi, Anna A1 - Hacker, Patricia A1 - Hauser, Christine A1 - Günthner, Roman A1 - Moser, Michaela A1 - Muggenthaler, Claudia A1 - Diehl-Schmid, Janine A1 - Priller, Josef A1 - Schmaderer, Christoph A1 - Grimmer, Timo T1 - Altered retinal cerebral vessel oscillation frequencies in Alzheimer's disease compatible with impaired amyloid clearance JF - Neurobiology of Aging N2 - Retinal vessels are similar to cerebral vessels in their structure and function. Moderately low oscillation frequencies of around 0.1 Hz have been reported as the driving force for paravascular drainage in gray matter in mice and are known as the frequencies of lymphatic vessels in humans. We aimed to elucidate whether retinal vessel oscillations are altered in Alzheimer's disease (AD) at the stage of dementia or mild cognitive impairment (MCI). Seventeen patients with mild-to-moderate dementia due to AD (ADD); 23 patients with MCI due to AD, and 18 cognitively healthy controls (HC) were examined using Dynamic Retinal Vessel Analyzer. Oscillatory temporal changes of retinal vessel diameters were evaluated using mathematical signal analysis. Especially at moderately low frequencies around 0.1 Hz, arterial oscillations in ADD and MCI significantly prevailed over HC oscillations and correlated with disease severity. The pronounced retinal arterial vasomotion at moderately low frequencies in the ADD and MCI groups would be compatible with the view of a compensatory upregulation of paravascular drainage in AD and strengthen the amyloid clearance hypothesis. KW - Alzheimer's disease KW - Retinal vessel analysis KW - Vasomotions KW - Pulsations KW - Mild cognitive impairment Y1 - 2022 U6 - http://dx.doi.org/10.1016/j.neurobiolaging.2022.08.012 SN - 0197-4580 VL - 120 SP - 117 EP - 127 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Kotliar, Konstantin A1 - Nagel, Edgar A1 - Vilser, Walthard A1 - Seidova, Seid-Fatima A1 - Lanzl, Ines T1 - Microstructural alterations of retinal arterial blood column along the vessel axis in systemic hypertension JF - Investigative Ophthalmology & Visual Science, IOVS N2 - Purpose: Image analysis by the retinal vessel analyzer (RVA) observes retinal vessels in their dynamic state online noninvasively along a chosen vessel segment. It has been found that high-frequency diameter changes in the retinal artery blood column along the vessel increase significantly in anamnestically healthy volunteers with increasing age and in patients with glaucoma during vascular dilation. This study was undertaken to investigate whether longitudinal sections of the retinal artery blood column are altered in systemic hypertension. Methods: Retinal arteries of 15 untreated patients with essential arterial hypertension (age, 50.9 ± 11.9 years) and of 15 age-matched anamnestically healthy volunteers were examined by RVA. After baseline assessment, a monochromatic luminance flicker (530–600 nm; 12.5 Hz; 20 s) was applied to evoke retinal vasodilation. Differences in amplitude and frequency of spatial artery blood column diameter change along segments (longitudinal arterial profiles) of 1 mm in length were measured and analyzed using Fourier transformation. Results: In the control group, average reduced power spectra (ARPS) of longitudinal arterial profiles did not differ when arteries changed from constriction to dilation. In the systemic hypertension group, ARPS during constriction, baseline, and restoration were identical and differed from ARPS during dilation (P < 0.05). Longitudinal arterial profiles in both groups showed significant dissimilitude at baseline and restoration (P < 0.05). Conclusions: The retinal artery blood column demonstrates microstructural alterations in systemic hypertension and is less irregular along the vessel axis during vessel dilation. These microstructural changes may be an indication of alterations in vessel wall rigidity, vascular endothelial function, and smooth muscle cells in this disease, leading to impaired perfusion and regulation. Y1 - 2010 U6 - http://dx.doi.org/10.1167/iovs.09-3649 SN - 0146-0404 VL - 51 IS - 4 SP - 2165 EP - 2172 PB - ARVO CY - Rockville, Md. ER - TY - JOUR A1 - Kotliar, Konstantin A1 - Nagel, Edgar A1 - Vilser, Walthard A1 - Lanzl, Ines M. T1 - Functional in vivo assessment of retinal artery microirregularities in glaucoma / Kotliar, Konstantin E. ; Nagel, Edgar ; Vilser, Walthard ; Lanzl, Ines M. JF - Acta Ophthalmologica. 86 (2008), H. 4 Y1 - 2008 SN - 1755-3768 SP - 424 EP - 433 PB - - ER - TY - JOUR A1 - Kotliar, Konstantin A1 - Mücke, Bruno A1 - Vilser, Walthard A1 - Schilling, Rudolf T1 - Effect of aging on retinal artery blood column diameter measured along the vessel axis / Kotliar, Konstantin E. ; Mücke, Bruno ; Vilser, Walthard ; Schilling, Rudolf ; Lanzl, Ines M. JF - Investigative Ophthalmology & Visual Science, IOVS. 49 (2008), H. 5 Y1 - 2008 SN - 0146-0404 SP - 2094 EP - 2102 PB - - ER - TY - JOUR A1 - Kotliar, Konstantin A1 - Mogilevskiĭ, A. Ia. A1 - Shilo, A. V. A1 - Panchekha, A. P. T1 - [Chaotic non-linear dynamics of alpha-band of the EEg and organization of the cortical activity of P300 wave] / Mogilevskiĭ, A. Ia. ; Kotliar, K. E. ; Shilo, A. V. ; Panchekha, A. P. JF - Zhurnal vyssheĭ nervnoĭ deiatelnosti imeni I P Pavlova. 58 (2008), H. 5 Y1 - 2008 SN - 0044-4677 N1 - Original in Russisch ; English abstract SP - 562 EP - 575 PB - - ER - TY - JOUR A1 - Kotliar, Konstantin A1 - Maier, Mathias A1 - Bauer, Svetlana A1 - Feucht, Nikolaus A1 - Lohmann, Chris A1 - Lanzl, Ines T1 - Intravitreal injection of triamcinolone acetonide and intraocular pressure: author's reply JF - Acta Ophthalmologica Y1 - 2008 SN - 1755-3768 VL - 86 IS - 6 SP - 692 EP - 693 PB - - ER - TY - JOUR A1 - Kotliar, Konstantin A1 - Maier, Mathias A1 - Bauer, Svetlana A1 - Feucht, Nikolaus T1 - Effect of intravitreal injections and volume changes on intraocular pressure: clinical results and biomechanical model / Kotliar, Konstantin ; Maier, Mathias ; Bauer, Svetlana ; Feucht, Nikolaus ; Lohmann, Chris ; Lanzl, Ines JF - Acta Ophthalmologica Scandinavica. 85 (2007), H. 7 Y1 - 2007 SN - 1755-3768 SP - 777 EP - 781 PB - - ER - TY - JOUR A1 - Kotliar, Konstantin A1 - Lanzl, Ines M. A1 - Schmidt-Trucksäss, A. A1 - Sitnikova, Diana A1 - Ali, Mohammad A1 - Blume, Katharina A1 - Halle, Martin A1 - Hansser, Henner T1 - Dynamic retinal vessel response to flicker in obesity: A methodological approach JF - Microvascular Research Y1 - 2011 SN - 0026-2862 VL - 81 IS - 1 SP - 123 EP - 128 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Kotliar, Konstantin A1 - Lanzl, Ines M. A1 - Maier, Mathias A1 - Feucht, Nikolaus T1 - Intraocular pressure effects of pegaptanib (macugen) injections in patients with and without glaucoma / Lanzl, Ines M. ; Maier, Mathias ; Feucht, Nikolaus ; Lohmann, Chris P. ; Kotliar, Konstantin E. JF - American Journal of Ophthalmology . 145 (2008), H. 1 Y1 - 2008 SN - 1879-1891 SP - 185 EP - 185 PB - - ER - TY - JOUR A1 - Kotliar, Konstantin A1 - Lanzl, Ines M. A1 - Hanssen, Henner A1 - Eberhardt, Karla A1 - Vilser, Walthard A1 - Halle, Martin A1 - Heemann, Uwe A1 - Schmidt-Trucksäss, Arno A1 - Baumann, Marcus T1 - Does increased blood pressure rather than aging influence retinal pulse wave velocity? JF - Investigative Ophthalmology & Visual Science, IOVS N2 - Purpose: It was demonstrated previously that retinal pulse wave velocity (rPWV) as a measure of retinal arterial stiffness is increased in aged anamnestically healthy volunteers compared with young healthy subjects. Using novel methodology of rPWV assessment this finding was confirmed and investigated whether it might relate to the increased blood pressure usually accompanying the aging process, rather than to the aging itself. Methods: A total of 12 young 25.5-year-old (24.0–28.8) [median(1st quartile–3rd quartile)] and 12 senior 68.5-year-old (63.8–71.8) anamnestically healthy volunteers; and 12 senior 63.0-year-old (60.8–65.0) validated healthy volunteers and 12 young 33.0-year-old (29.5–35.0) hypertensive patients were examined. Time-dependent alterations of vessel diameter were assessed by the Dynamic Vessel Analyzer in a retinal artery of each subject. The data were filtered and processed using mathematical signal analysis and rPWVs were calculated. Results: rPWV amounted to 1200 (990-1470) RU (relative units)/s in the hypertensive group and to 1040 (700-2230) RU/s in anamnestically healthy seniors. These differed significantly from rPWVs in young healthy group (410 [280–500] RU/s) and in validated healthy seniors (400 [320–510] RU/s). rPWV associated with age and mean arterial pressure (MAP) in the pooled cohort excluded validated healthy seniors. In a regression model these associations remain when alternately adjusted for MAP and age. When including validated healthy seniors in the pooled cohort only association with MAP remains. Conclusions: Both aging (with not excluded cardiovascular risk factors) and mild hypertension are associated with elevated rPWV. rPWV increases to a similar extent both in young mildly hypertensive subjects and in aged anamnestically healthy persons. Healthy aging is not associated with increased rPWV. Y1 - 2012 U6 - http://dx.doi.org/10.1167/iovs.11-8815 SN - 0146-0404 VL - 53 IS - 4 SP - 2119 EP - 2126 PB - ARVO CY - Rockville, Md. ER - TY - JOUR A1 - Kotliar, Konstantin A1 - Lanzl, Ines M. T1 - Can vascular function be assessed by the interpretation of retinal vascular diameter changes? JF - Investigative Ophthalmology & Visual Science, IOVS. 52 (2011), H. 1 Y1 - 2011 SN - 0146-0404 SP - 635 EP - 636 PB - ARVO CY - Rockville, Md. ER - TY - JOUR A1 - Kotliar, Konstantin A1 - Kozlova, Tatiana V. A1 - Lanzl, Ines M. T1 - Postoperative aqueous outflow in the human eye after glaucoma filtration surgery: biofluidmechanical considerations JF - Biomedizinische Technik = Biomedical Engineering Y1 - 2009 SN - 1862-278X VL - 54 IS - 1 SP - 14 EP - 22 PB - - ER - TY - JOUR A1 - Kotliar, Konstantin A1 - Koshitz, I. N. A1 - Svetlowa, O. V. A1 - Zaseeva, M. V. T1 - Physiological principles of hypotensive therapy of open-angle glaucoma during presbyopic period. Part II Promising algorithms of practical sparing applications / Koshitz, I. N. ; Svetlova, O. V. ; Zaseeva, M. V. ; Shuhaev, S. V. ; Makarov, F. N. ; Kotliar JF - Glaukoma (2006) Y1 - 2006 N1 - Original in Russisch SP - 51 EP - 70 PB - - ER - TY - JOUR A1 - Kotliar, Konstantin A1 - Koshitz, I. N. A1 - Svetlowa, O. V. A1 - Makarov, F. N. T1 - Biomechanical analysis of traditional and contemporary conceptions on pathogenesis of the primary open angle glaucoma / Koshitz, I. N. ; Svetlova, O. V. ; Kotliar, K. E. ; Makarov, F. N. ; Smolnikov, B. A. JF - Glaukoma (2005) Y1 - 2005 N1 - Original in Russisch SP - 41 EP - 63 PB - - ER - TY - JOUR A1 - Kotliar, Konstantin A1 - Koshitz, I. N. A1 - Svetlova, O. V. A1 - Zaseeva, M. V. T1 - Physiological principles of hypotensive therapy of open-angle glaucoma during presbyopic period. Part I Initial theoretical presuppositions, hypotheses and facts / Koshitz, I. N. ; Svetlova, O. V. ; Zaseeva, M. V. ; Shuhaev, S. V. ; Makarov, F. N. ; Kotli JF - Glaukoma (2006) Y1 - 2006 N1 - Original in Russisch SP - 35 EP - 53 PB - - ER - TY - JOUR A1 - Kotliar, Konstantin A1 - Kharoubi, A. A1 - Schmidt-Trucksäß, A. A1 - Halle, M. A1 - Lanzl, I. T1 - Does internal longitudinal microstructure of retinal veins change with age in medically healthy persons? JF - Acta Ophthalmologica Y1 - 2009 SN - 1600-0420 (E-Journal); 1755-3768 (E-Journal); 0001-639X (Print); 1395-3907 (Print); 1755-375X (Print) VL - Vol. 87 IS - Suppl. S244 SP - 0 PB - Wiley CY - Weinheim ER - TY - JOUR A1 - Kotliar, Konstantin A1 - Hauser, Christine A1 - Ortner, Marion A1 - Muggenthaler, Claudia A1 - Diehl-Schmid, Janine A1 - Angermann, Susanne A1 - Hapfelmeier, Alexander A1 - Schmaderer, Christoph A1 - Grimmer, Timo T1 - Altered neurovascular coupling as measured by optical imaging: a biomarker for Alzheimer’s disease JF - Scientific Reports Y1 - 2017 U6 - http://dx.doi.org/10.1038/s41598-017-13349-5 SN - 2045-2322 N1 - Article 12906 VL - 7 IS - 1 SP - 1 EP - 11 PB - Springer Nature CY - Cham ER - TY - JOUR A1 - Kotliar, Konstantin A1 - Hanssen, Henner A1 - Eberhardt, Karla A1 - Vilser, Walthard A1 - Schmaderer, Christoph A1 - Halle, Martin A1 - Heemann, Uwe A1 - Baumann, M. T1 - Retinal pulse wave velocity in young male normotensive and mildly hypertensive subjects JF - Microcirculation Y1 - 2013 SN - 1549-8719 N1 - Accepted Article (Accepted, unedited articles published online and citable. The final edited and typeset version of record will appear in future.) PB - Wiley CY - Malden ER - TY - JOUR A1 - Kotliar, Konstantin A1 - Baumann, Marcus A1 - Vilser, Walthard A1 - Lanzl, Ines M. T1 - Pulse wave velocity in retinal arteries of healthy volunteers JF - British Journal of Ophthalmology (eBJO) Y1 - 2011 SN - 1468-2079 VL - 95 IS - 11 SP - 675 EP - 679 PB - BMJ Publ. Group CY - London ER - TY - JOUR A1 - Kotliar, Konstantin A1 - Bauer, S. M. A1 - Zamuraev, L. A. T1 - Model of the transversely isotropic spherical layer for estimation of intraocular pressure changes after intravitreal injections / Bauer, S. M. ; Zamuraev, L. A. ; Kotliar, K. E. JF - Rossiiskii zhurnal biomekhaniki = Russian Journal of biomechanics. 10 (2006), H. 2 Y1 - 2006 SN - 1812-5123 SP - 41 EP - 47 PB - - ER - TY - THES A1 - Kotliar, Konstantin T1 - Functional in-vivo assessment and biofluidmechanical analysis of age-related and pathological microstructural changes in retinal vessels [Elektronische Ressource] Y1 - 2008 N1 - München, Techn. Univ., Diss., 2008 PB - - ER - TY - CHAP A1 - Kotliar, Konstantin ED - Pallikaris, I. ED - Tsilimbaris, M. K. ED - Dastiridou, A. I. T1 - Ocular rigidity: clinical approach T2 - Ocular Rigidity, Biomechanics and Hydrodynamics of the Eye N2 - The term ocular rigidity is widely used in clinical ophthalmology. Generally it is assumed as a resistance of the whole eyeball to mechanical deformation and relates to biomechanical properties of the eye and its tissues. Basic principles and formulas for clinical tonometry, tonography and pulsatile ocular blood flow measurements are based on the concept of ocular rigidity. There is evidence for altered ocular rigidity in aging, in several eye diseases and after eye surgery. Unfortunately, there is no consensual view on ocular rigidity: it used to make a quite different sense for different people but still the same name. Foremost there is no clear consent between biomechanical engineers and ophthalmologists on the concept. Moreover ocular rigidity is occasionally characterized using various parameters with their different physical dimensions. In contrast to engineering approach, clinical approach to ocular rigidity claims to characterize the total mechanical response of the eyeball to its deformation without any detailed considerations on eye morphology or material properties of its tissues. Further to the previous chapter this section aims to describe clinical approach to ocular rigidity from the perspective of an engineer in an attempt to straighten out this concept, to show its advantages, disadvantages and various applications. KW - Coefficient of ocular rigidity KW - Eyeball KW - Corneo-scleral shell KW - Pressure-volume relationship KW - Differential tonometry Y1 - 2021 SN - 978-3-030-64422-2 U6 - http://dx.doi.org/10.1007/978-3-030-64422-2_2 SP - 15 EP - 43 PB - Springer CY - Cham ER - TY - JOUR A1 - Kopp, Alexander A1 - Schunck, Laura A1 - Gosau, Martin A1 - Smeets, Ralf A1 - Burg, Simon A1 - Fuest, Sandra A1 - Kröger, Nadja A1 - Zinser, Max A1 - Krohn, Sebastian A1 - Behbahani, Mehdi A1 - Köpf, Marius A1 - Lauts, Lisa A1 - Rutkowski, Rico T1 - Influence of the casting concentration on the mechanical and optical properties of Fa/CaCl2-derived silk fibroin membranes JF - International Journal of Molecular Sciences N2 - In this study, we describe the manufacturing and characterization of silk fibroin membranes derived from the silkworm Bombyx mori. To date, the dissolution process used in this study has only been researched to a limited extent, although it entails various potential advantages, such as reduced expenses and the absence of toxic chemicals in comparison to other conventional techniques. Therefore, the aim of this study was to determine the influence of different fibroin concentrations on the process output and resulting membrane properties. Casted membranes were thus characterized with regard to their mechanical, structural and optical assets via tensile testing, SEM, light microscopy and spectrophotometry. Cytotoxicity was evaluated using BrdU, XTT, and LDH assays, followed by live–dead staining. The formic acid (FA) dissolution method was proven to be suitable for the manufacturing of transparent and mechanically stable membranes. The fibroin concentration affects both thickness and transparency of the membranes. The membranes did not exhibit any signs of cytotoxicity. When compared to other current scientific and technical benchmarks, the manufactured membranes displayed promising potential for various biomedical applications. Further research is nevertheless necessary to improve reproducible manufacturing, including a more uniform thickness, less impurity and physiological pH within the membranes. Y1 - 2020 U6 - http://dx.doi.org/10.3390/ijms21186704 SN - 1422-0067 N1 - Special issue: Optimization of Biomaterials for Reconstructive and Regenerative Medicine VL - 21 IS - 18 art. no. 6704 PB - MDPI CY - Basel ER - TY - JOUR A1 - Kopp, Alexander A1 - Schmeets, Ralf A1 - Gosau, Martin A1 - Friedrich, Reinhard E. A1 - Fuest, Sandra A1 - Behbahani, Mehdi A1 - Barbeck, Mike A1 - Rutkowski, Rico A1 - Burg, Simon A1 - Kluwe, Lan A1 - Henningsen, Anders T1 - Production and Characterization of Porous Fibroin Scaffolds for Regenerative Medical Application JF - In Vivo Y1 - 2019 U6 - http://dx.doi.org/10.21873/invivo.11536 SN - 1791-7549 VL - 33 IS - 3 SP - 757 EP - 762 ER - TY - CHAP A1 - Kolditz, Melanie A1 - Albracht, Kirsten A1 - Fasse, Alessandro A1 - Albin, Thivaharan A1 - Brüggemann, Gert-Peter A1 - Abel, Dirk T1 - Evaluation of an industrial robot as a leg press training device T2 - XV International Symposium on Computer Simulation in Biomechanics July 9th – 11th 2015, Edinburgh, UK Y1 - 2015 SP - 41 EP - 42 ER - TY - CHAP A1 - Kolditz, Melanie A1 - Albin, Thivaharan A1 - Fasse, Alessandro A1 - Brüggemann, Gert-Peter A1 - Abel, Dirk A1 - Albracht, Kirsten T1 - Simulative Analysis of Joint Loading During Leg Press Exercise for Control Applications T2 - IFAC-PapersOnLine Y1 - 2015 U6 - http://dx.doi.org/10.1016/j.ifacol.2015.10.179 N1 - IFAC-PapersOnLine 48-20; Conference Paper Archive VL - 48 IS - 20 SP - 435 EP - 440 ER - TY - JOUR A1 - Kolditz, Melanie A1 - Albin, Thivaharan A1 - Abel, Dirk A1 - Fasse, Alessandro A1 - Brüggemann, Gert-Peter A1 - Albracht, Kirsten T1 - Evaluation of foot position and orientation as manipulated variables to control external knee adduction moments in leg extension training JF - Computer methods and programs in biomedicine N2 - Background and Objective Effective leg extension training at a leg press requires high forces, which need to be controlled to avoid training-induced damage. In order to avoid high external knee adduction moments, which are one reason for unphysiological loadings on knee joint structures, both training movements and the whole reaction force vector need to be observed. In this study, the applicability of lateral and medial changes in foot orientation and position as possible manipulated variables to control external knee adduction moments is investigated. As secondary parameters both the medio-lateral position of the center of pressure and the frontal-plane orientation of the reaction force vector are analyzed. Methods Knee adduction moments are estimated using a dynamic model of the musculoskeletal system together with the measured reaction force vector and the motion of the subject by solving the inverse kinematic and dynamic problem. Six different foot conditions with varying positions and orientations of the foot in a static leg press are evaluated and compared to a neutral foot position. Results Both lateral and medial wedges under the foot and medial and lateral shifts of the foot can influence external knee adduction moments in the presented study with six healthy subjects. Different effects are observed with the varying conditions: the pose of the leg is changed and the direction and center of pressure of the reaction force vector is influenced. Each effect results in a different direction or center of pressure of the reaction force vector. Conclusions The results allow the conclusion that foot position and orientation can be used as manipulated variables in a control loop to actively control knee adduction moments in leg extension training. KW - External knee adduction moments KW - Manipulated variables KW - Inverse dynamic problem KW - Inverse kinematic problem KW - Musculoskeletal model Y1 - 2016 U6 - http://dx.doi.org/10.1016/j.cmpb.2016.09.005 SN - 0169-2607 N1 - Part of special issue: "SI: Personalised Models and System Identification" VL - 171 SP - 81 EP - 86 PB - Elsevier CY - Amsterdam ER - TY - CHAP A1 - Kohl, Philipp A1 - Schmidts, Oliver A1 - Klöser, Lars A1 - Werth, Henri A1 - Kraft, Bodo A1 - Zündorf, Albert T1 - STAMP 4 NLP – an agile framework for rapid quality-driven NLP applications development T2 - Quality of Information and Communications Technology. QUATIC 2021 N2 - The progress in natural language processing (NLP) research over the last years, offers novel business opportunities for companies, as automated user interaction or improved data analysis. Building sophisticated NLP applications requires dealing with modern machine learning (ML) technologies, which impedes enterprises from establishing successful NLP projects. Our experience in applied NLP research projects shows that the continuous integration of research prototypes in production-like environments with quality assurance builds trust in the software and shows convenience and usefulness regarding the business goal. We introduce STAMP 4 NLP as an iterative and incremental process model for developing NLP applications. With STAMP 4 NLP, we merge software engineering principles with best practices from data science. Instantiating our process model allows efficiently creating prototypes by utilizing templates, conventions, and implementations, enabling developers and data scientists to focus on the business goals. Due to our iterative-incremental approach, businesses can deploy an enhanced version of the prototype to their software environment after every iteration, maximizing potential business value and trust early and avoiding the cost of successful yet never deployed experiments. KW - Machine learning KW - Process model KW - Natural language processing Y1 - 2021 SN - 978-3-030-85346-4 SN - 978-3-030-85347-1 U6 - http://dx.doi.org/10.1007/978-3-030-85347-1_12 N1 - International Conference on the Quality of Information and Communications Technology, QUATIC 2021, 8-11 September, Algarve, Portugal SP - 156 EP - 166 PB - Springer CY - Cham ER - TY - CHAP A1 - Kohl, Philipp A1 - Freyer, Nils A1 - Krämer, Yoka A1 - Werth, Henri A1 - Wolf, Steffen A1 - Kraft, Bodo A1 - Meinecke, Matthias A1 - Zündorf, Albert ED - Conte, Donatello ED - Fred, Ana ED - Gusikhin, Oleg ED - Sansone, Carlo T1 - ALE: a simulation-based active learning evaluation framework for the parameter-driven comparison of query strategies for NLP T2 - Deep Learning Theory and Applications. DeLTA 2023. Communications in Computer and Information Science N2 - Supervised machine learning and deep learning require a large amount of labeled data, which data scientists obtain in a manual, and time-consuming annotation process. To mitigate this challenge, Active Learning (AL) proposes promising data points to annotators they annotate next instead of a subsequent or random sample. This method is supposed to save annotation effort while maintaining model performance. However, practitioners face many AL strategies for different tasks and need an empirical basis to choose between them. Surveys categorize AL strategies into taxonomies without performance indications. Presentations of novel AL strategies compare the performance to a small subset of strategies. Our contribution addresses the empirical basis by introducing a reproducible active learning evaluation (ALE) framework for the comparative evaluation of AL strategies in NLP. The framework allows the implementation of AL strategies with low effort and a fair data-driven comparison through defining and tracking experiment parameters (e.g., initial dataset size, number of data points per query step, and the budget). ALE helps practitioners to make more informed decisions, and researchers can focus on developing new, effective AL strategies and deriving best practices for specific use cases. With best practices, practitioners can lower their annotation costs. We present a case study to illustrate how to use the framework. KW - Active learning KW - Query learning KW - Natural language processing KW - Deep learning KW - Reproducible research Y1 - 2023 SN - 978-3-031-39058-6 (Print) SN - 978-3-031-39059-3 (Online) U6 - http://dx.doi.org/978-3-031-39059-3 N1 - 4th International Conference, DeLTA 2023, Rome, Italy, July 13–14, 2023. SP - 235 EP - 253 PB - Springer CY - Cham ER - TY - JOUR A1 - Kodomskoi, Leonid A1 - Kotliar, Konstantin A1 - Schröder, Andreas A1 - Weiss, Michael A1 - Hille, Konrad T1 - Suture-Probe Canaloplasty as an Alternative to Canaloplasty using the iTrack™ Microcatheter JF - Journal of Glaucoma Y1 - 2019 U6 - http://dx.doi.org/10.1097/IJG.0000000000001321 SN - 1057-0829 IS - Epub ahead of print PB - Lippincott Williams & Wilkins CY - Philadelphia ER - TY - CHAP A1 - Koch, Claudia A1 - Poghossian, Arshak A1 - Wege, Christina A1 - Schöning, Michael Josef ED - Wege, Christina T1 - TMV-Based Adapter Templates for Enhanced Enzyme Loading in Biosensor Applications T2 - Virus-Derived Nanoparticles for Advanced Technologies N2 - Nanotubular tobacco mosaic virus (TMV) particles and RNA-free lower-order coat protein (CP) aggregates have been employed as enzyme carriers in different diagnostic layouts and compared for their influence on biosensor performance. In the following, we describe a label-free electrochemical biosensor for improved glucose detection by use of TMV adapters and the enzyme glucose oxidase (GOD). A specific and efficient immobilization of streptavidin-conjugated GOD ([SA]-GOD) complexes on biotinylated TMV nanotubes or CP aggregates was achieved via bioaffinity binding. Glucose sensors with adsorptively immobilized [SA]-GOD, and with [SA]-GOD cross-linked with glutardialdehyde, respectively, were tested in parallel on the same sensor chip. Comparison of these sensors revealed that TMV adapters enhanced the amperometric glucose detection remarkably, conveying highest sensitivity, an extended linear detection range and fastest response times. These results underline a great potential of an integration of virus/biomolecule hybrids with electronic transducers for applications in biosensorics and biochips. Here, we describe the fabrication and use of amperometric sensor chips combining an array of circular Pt electrodes, their loading with GOD-modified TMV nanotubes (and other GOD immobilization methods), and the subsequent investigations of the sensor performance. KW - Tobacco mosaic virus (TMV) KW - Coat protein KW - Enzyme nanocarrier KW - Glucose biosensor KW - Glucose oxidase Y1 - 2018 SN - 978-1-4939-7808-3 U6 - http://dx.doi.org/10.1007/978-1-4939-7808-3 N1 - Methods in Molecular Biology, vol 1776 SP - 553 EP - 568 PB - Humana Press CY - New York, NY ER - TY - JOUR A1 - Koch, Claudia A1 - Poghossian, Arshak A1 - Schöning, Michael Josef A1 - Wege, Christian T1 - Penicillin Detection by Tobacco Mosaic Virus-Assisted Colorimetric Biosensors JF - Nanotheranostics N2 - The presentation of enzymes on viral scaffolds has beneficial effects such as an increased enzyme loading and a prolonged reusability in comparison to conventional immobilization platforms. Here, we used modified tobacco mosaic virus (TMV) nanorods as enzyme carriers in penicillin G detection for the first time. Penicillinase enzymes were conjugated with streptavidin and coupled to TMV rods by use of a bifunctional biotin-linker. Penicillinase-decorated TMV particles were characterized extensively in halochromic dye-based biosensing. Acidometric analyte detection was performed with bromcresol purple as pH indicator and spectrophotometry. The TMV-assisted sensors exhibited increased enzyme loading and strongly improved reusability, and higher analysis rates compared to layouts without viral adapters. They extended the half-life of the sensors from 4 - 6 days to 5 weeks and thus allowed an at least 8-fold longer use of the sensors. Using a commercial budget-priced penicillinase preparation, a detection limit of 100 µM penicillin was obtained. Initial experiments also indicate that the system may be transferred to label-free detection layouts. Y1 - 2018 U6 - http://dx.doi.org/10.7150/ntno.22114 SN - 2206-7418 VL - 2 IS - 2 SP - 184 EP - 196 PB - Ivyspring CY - Sydney ER - TY - JOUR A1 - Knox, Ronald A1 - Bruggemann, Andrea A1 - Gossmann, Matthias A1 - Thomas, Ulrich A1 - Horváth, András A1 - Dragicevic, Elena A1 - Stoelzle-Feix, Sonja A1 - Fertig, Niels A1 - Jung, Alexander A1 - Raman, Aravind Hariharan A1 - Staat, Manfred A1 - Linder, Peter T1 - Combining physiological relevance and throughput for in vitro cardiac contractility measurement JF - Biophysical Journal N2 - Despite increasing acceptance of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) in safety pharmacology, controversy remains about the physiological relevance of existing in vitro models for their mechanical testing. We hypothesize that existing signs of immaturity of the cell models result from an improper mechanical environment. We cultured hiPSC-CMs in a 96-well format on hyperelastic silicone membranes imitating their native mechanical environment, resulting in physiological responses to compound stimuli.We validated cell responses on the FLEXcyte 96, with a set of reference compounds covering a broad range of cellular targets, including ion channel modulators, adrenergic receptor modulators and kinase inhibitors. Acute (10 - 30 min) and chronic (up to 7 days) effects were investigated. Furthermore, the measurements were complemented with electromechanical models based on electrophysiological recordings of the used cell types.hiPSC-CMs were cultured on freely-swinging, ultra-thin and hyperelastic silicone membranes. The weight of the cell culture medium deflects the membranes downwards. Rhythmic contraction of the hiPSC-CMs resulted in dynamic deflection changes which were quantified by capacitive distance sensing. The cells were cultured for 7 days prior to compound addition. Acute measurements were conducted 10-30 minutes after compound addition in standard culture medium. For chronic treatment, compound-containing medium was replaced daily for up to 7 days. Electrophysiological properties of the employed cell types were recorded by automated patch-clamp (Patchliner) and the results were integrated into the electromechanical model of the system.Calcium channel agonist S Bay K8644 and beta-adrenergic stimulator isoproterenol induced significant positive inotropic responses without additional external stimulation. Kinase inhibitors displayed cardiotoxic effects on a functional level at low concentrations. The system-integrated analysis detected alterations in beating shape as well as frequency and arrhythmic events and we provide a quantitative measure of these. Y1 - 2020 U6 - http://dx.doi.org/10.1016/j.bpj.2019.11.3104 SN - 0006-3495 N1 - Raman, Arayind Hariharan im Artikel unter dem Namen: Raman, Alexander H. VL - 118 IS - Issue 3, Supplement 1 SP - 570a PB - Elsevier CY - Amsterdam ER - TY - CHAP A1 - Knott, Thomas C. A1 - Sofronia, Raluca E. A1 - Gerressen, Marcus A1 - Law, Yuen A1 - Davidescu, Arjana A1 - Savii, George G. A1 - Gatzweiler, Karl-Heinz A1 - Staat, Manfred A1 - Kuhlen, Torsten W. T1 - Preliminary bone sawing model for a virtual reality-based training simulator of bilateral sagittal split osteotomy T2 - Biomedical simulation : 6th International Symposium, ISBMS 2014, Strasbourg, France, October 16-17, 2014 : proceedings (Lecture notes in computer science : vol. 8789) N2 - Successful bone sawing requires a high level of skill and experience, which could be gained by the use of Virtual Reality-based simulators. A key aspect of these medical simulators is realistic force feedback. The aim of this paper is to model the bone sawing process in order to develop a valid training simulator for the bilateral sagittal split osteotomy, the most often applied corrective surgery in case of a malposition of the mandible. Bone samples from a human cadaveric mandible were tested using a designed experimental system. Image processing and statistical analysis were used for the selection of four models for the bone sawing process. The results revealed a polynomial dependency between the material removal rate and the applied force. Differences between the three segments of the osteotomy line and between the cortical and cancellous bone were highlighted. KW - Bone sawing KW - virtual reality KW - training simulator Y1 - 2014 SN - 978-3-319-12057-7 (Online) SN - 978-3-319-12056-0 (Print) U6 - http://dx.doi.org/10.1007/978-3-319-12057-7_1 SP - 1 EP - 10 PB - Springer CY - Cham ER - TY - JOUR A1 - Knobe, M. A1 - Giesen, M. A1 - Plate, S. A1 - Gradl-Dietsch, G. A1 - Buecking, B. A1 - Eschbach, D. A1 - Laack, Walter van A1 - Pape, H.-C. T1 - The Aachen mobility and balance index to measure physiological falls risk: a comparison with the Tinetti POMA scale JF - European Journal Of Trauma And Emergency Surgery N2 - Purpose The most commonly used mobility assessments for screening risk of falls among older adults are rating scales such as the Tinetti performance oriented mobility assessment (POMA). However, its correlation with falls is not always predictable and disadvantages of the scale include difficulty to assess many of the items on a 3-point scale and poor specificity. The purpose of this study was to describe the ability of the new Aachen Mobility and Balance Index (AMBI) to discriminate between subjects with a fall history and subjects without such events in comparison to the Tinetti POMA Scale. Methods For this prospective cohort study, 24 participants in the study group and 10 in the control group were selected from a population of patients in our hospital who had met the stringent inclusion criteria. Both groups completed the Tinetti POMA Scale (gait and balance component) and the AMBI (tandem stance, tandem walk, ten-meter-walk-test, sit-to-stand with five repetitions, 360° turns, timed-up-and-go-test and measurement of the dominant hand grip strength). A history of falls and hospitalization in the past year were evaluated retrospectively. The relationships among the mobility tests were examined with Bland–Altmananalysis. Receiver-operated characteristics curves, sensitivity and specificity were calculated. Results The study showed a strong negative correlation between the AMBI (17 points max., highest fall risk) and Tinetti POMA Scale (28 points max., lowest fall risk; r = −0.78, p < 0.001) with an excellent discrimination between community-dwelling older people and a younger control group. However, there were no differences in any of the mobility and balance measurements between participants with and without a fall history with equal characteristics in test comparison (AMBI vs. Tinetti POMA Scale: AUC 0.570 vs. 0.598; p = 0.762). The Tinetti POMA Scale (cut-off <20 points) showed a sensitivity of 0.45 and a specificity of 0.69, the AMBI a sensitivity of 0.64 and a specificity of 0.46 (cut-off >5 points). Conclusion The AMBI comprises mobility and balance tasks with increasing difficulty as well as a measurement of the dominant hand-grip strength. Its ability to identify fallers was comparable to the Tinetti POMA Scale. However, both measurement sets showed shortcomings in discrimination between fallers and non-fallers based on a self-reported retrospective falls-status. KW - Tinetti test KW - Mobility KW - Mobility tests KW - Ground-level falls KW - Elderly KW - Fall prevention KW - Co-managed care KW - Balance Y1 - 2016 U6 - http://dx.doi.org/10.1007/s00068-016-0693-2 SN - 1863-9941 VL - 42 IS - 5 SP - 537 EP - 545 PB - Springer CY - Berlin ER - TY - CHAP A1 - Klöser, Lars A1 - Kohl, Philipp A1 - Kraft, Bodo A1 - Zündorf, Albert T1 - Multi-attribute relation extraction (MARE): simplifying the application of relation extraction T2 - Proceedings of the 2nd International Conference on Deep Learning Theory and Applications - DeLTA N2 - Natural language understanding’s relation extraction makes innovative and encouraging novel business concepts possible and facilitates new digitilized decision-making processes. Current approaches allow the extraction of relations with a fixed number of entities as attributes. Extracting relations with an arbitrary amount of attributes requires complex systems and costly relation-trigger annotations to assist these systems. We introduce multi-attribute relation extraction (MARE) as an assumption-less problem formulation with two approaches, facilitating an explicit mapping from business use cases to the data annotations. Avoiding elaborated annotation constraints simplifies the application of relation extraction approaches. The evaluation compares our models to current state-of-the-art event extraction and binary relation extraction methods. Our approaches show improvement compared to these on the extraction of general multi-attribute relations. Y1 - 2021 SN - 978-989-758-526-5 U6 - http://dx.doi.org/10.5220/0010559201480156 N1 - Proceedings of the 2nd International Conference on Deep Learning Theory and Applications, DeLTA2021, July 7-9, 2021 SP - 148 EP - 156 ER - TY - CHAP A1 - Klöser, Lars A1 - Büsgen, André A1 - Kohl, Philipp A1 - Kraft, Bodo A1 - Zündorf, Albert ED - Conte, Donatello ED - Fred, Ana ED - Gusikhin, Oleg ED - Sansone, Carlo T1 - Explaining relation classification models with semantic extents T2 - DeLTA 2023: Deep Learning Theory and Applications N2 - In recent years, the development of large pretrained language models, such as BERT and GPT, significantly improved information extraction systems on various tasks, including relation classification. State-of-the-art systems are highly accurate on scientific benchmarks. A lack of explainability is currently a complicating factor in many real-world applications. Comprehensible systems are necessary to prevent biased, counterintuitive, or harmful decisions. We introduce semantic extents, a concept to analyze decision patterns for the relation classification task. Semantic extents are the most influential parts of texts concerning classification decisions. Our definition allows similar procedures to determine semantic extents for humans and models. We provide an annotation tool and a software framework to determine semantic extents for humans and models conveniently and reproducibly. Comparing both reveals that models tend to learn shortcut patterns from data. These patterns are hard to detect with current interpretability methods, such as input reductions. Our approach can help detect and eliminate spurious decision patterns during model development. Semantic extents can increase the reliability and security of natural language processing systems. Semantic extents are an essential step in enabling applications in critical areas like healthcare or finance. Moreover, our work opens new research directions for developing methods to explain deep learning models. KW - Relation classification KW - Natural language processing KW - Natural language understanding KW - Information extraction KW - Trustworthy artificial intelligence Y1 - 2023 SN - 978-3-031-39058-6 (Print) SN - 978-3-031-39059-3 (Online) U6 - http://dx.doi.org/10.1007/978-3-031-39059-3_13 N1 - 4th International Conference, DeLTA 2023, Rome, Italy, July 13–14, 2023. SP - 189 EP - 208 PB - Springer CY - Cham ER - TY - CHAP A1 - Kloock, Joachim P. A1 - Schöning, Michael Josef T1 - Heavy metal detection with semiconductor devices based on PLD-prepared chalcogenide glass thin films T2 - Armenian Journal of Physics Y1 - 2007 SN - 1829-1171 SP - 95 EP - 98 ER - TY - CHAP A1 - Kloock, Joachim P. A1 - Schubert, J. A1 - Ermelenko, Y. A1 - Vlasov, Y. G. A1 - Bratov, A. A1 - Schöning, Michael Josef T1 - Thin-film sensors with chalcogenide glass materials – a general survey T2 - Biochemical sensing utilisation of micro- and nanotechnologies : Warsaw, [23rd - 26th] November 2005 / ed. by M. Mascini ... Y1 - 2006 SP - 92 EP - 97 CY - Warsaw ER - TY - JOUR A1 - Kloock, Joachim P. A1 - Mourzina, Y.G. A1 - Ermolenko, Y. A1 - Doll, T. A1 - Schubert, J. A1 - Schöning, Michael Josef T1 - Inorganic thin-film sensor membranes with PLD-prepared chalcogenide glasses: Challenges and implementation JF - Sensors. 4 (2004), H. 10 Y1 - 2004 SN - 1424-8220 SP - 156 EP - 162 ER - TY - JOUR A1 - Kloock, Joachim P. A1 - Mourzina, Y. A1 - Schubert, J. A1 - Ermelenko, Y. A1 - Schöning, Michael Josef T1 - Pulsed laser deposition: A tool for fabricating thin-film microsensors JF - Biomedizinische Technik. 49 (2004), H. 2 Y1 - 2004 SN - 0932-4666 SP - 1032 EP - 1033 ER - TY - JOUR A1 - Kloock, Joachim P. A1 - Moreno, Lia A1 - Bratov, A. A1 - Huachupoma, S. A1 - Xu, J. A1 - Wagner, Torsten A1 - Yoshinobu, T. A1 - Ermolenko, Y. A1 - Vlasov, Y. G. A1 - Schöning, Michael Josef T1 - PLD-prepared cadmium sensors based on chalcogenide glasses —ISFET, LAPS and μISE semiconductor structures JF - Sensors and Actuators B: Chemical. 118 (2006), H. 1-2 Y1 - 2006 SN - 0925-4005 N1 - Eurosensors XIX - Eurosensors XIX - The 19th European Conference on Solid-State Transducers SP - 149 EP - 155 ER - TY - JOUR A1 - Kleefeld, A. A1 - Reißel, Martin T1 - The Levenberg–Marquardt method applied to a parameter estimation problem arising from electrical resistivity tomography JF - Applied Mathematics and Computation Y1 - 2011 SN - 0096-3003 VL - 217 IS - 9 SP - 4490 EP - 4501 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Kirchner, Patrick A1 - Reisert, Steffen A1 - Pütz, Patrick A1 - Keusgen, Michael A1 - Schöning, Michael Josef T1 - Characterisation of polymeric materials as passivation layer for calorimetric H2O2 gas sensors JF - Physica Status Solidi (a) N2 - Calorimetric gas sensors for monitoring the H₂O₂ concentration at elevated temperatures in industrial sterilisation processes have been presented in previous works. These sensors are built up in form of a differential set-up of a catalytically active and passive temperature-sensitive structure. Although, various types of catalytically active dispersions have been studied, the passivation layer has to be established and therefore, chemically as well as physically characterised. In the present work, fluorinated ethylene propylene (FEP), perfluoralkoxy (PFA) and epoxy-based SU-8 photoresist as temperature-stable polymeric materials have been investigated for sensor passivation in terms of their chemical inertness against H₂O₂, their hygroscopic properties as well as their morphology. The polymeric materials were deposited via spin-coating on the temperature-sensitive structure, wherein spin-coated FEP and PFA show slight agglomerates. However, they possess a low absorption of humidity due to their hydrophobic surface, whereas the SU-8 layer has a closed surface but shows a slightly higher absorption of water. All of them were inert against gaseous H₂O₂ during the characterisation in H₂O₂ atmosphere that demonstrates their suitability as passivation layer for calorimetric H₂O₂ gas sensors. Y1 - 2012 U6 - http://dx.doi.org/10.1002/pssa.201100773 SN - 1862-6319 VL - 209 IS - 5 SP - 859 EP - 863 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Kirchner, Patrick A1 - Oberländer, Jan A1 - Suso, Henri-Pierre A1 - Rysstad, Gunnar A1 - Keusgen, Michael A1 - Schöning, Michael Josef T1 - Towards a wireless sensor system for real-time H2O2 monitoring in aseptic food processes JF - Physica status solidi (a) N2 - A wireless sensor system based on the industrial ZigBee standard for low-rate wireless networking was developed that enables real-time monitoring of gaseous H2O2 during the package sterilization in aseptic food processes. The sensor system consists of a remote unit connected to a calorimetric gas sensor, which was already established in former works, and an external base unit connected to a laptop computer. The remote unit was built up by an XBee radio frequency (RF) module for data communication and a programmable system-on-chip controller to read out the sensor signal and process the sensor data, whereas the base unit is a second XBee RF module. For the rapid H2O2 detection on various locations inside the package that has to be sterilized, a novel read-out strategy of the calorimetric gas sensor was established, wherein the sensor response is measured within the short sterilization time and correlated with the present H2O2 concentration. In an exemplary measurement application in an aseptic filling machinery, the suitability of the new, wireless sensor system was demonstrated, wherein the influence of the gas velocity on the H2O2 distribution inside a package was determined and verified with microbiological tests. KW - calorimetric gas sensor;hydrogen peroxide;wireless sensor system Y1 - 2013 U6 - http://dx.doi.org/10.1002/pssa.201200920 SN - 1862-6319 VL - 210 IS - 5 SP - 877 EP - 883 PB - Wiley CY - Weinheim ER - TY - JOUR A1 - Kirchner, Patrick A1 - Oberländer, Jan A1 - Suco, Henri-Pierre A1 - Rysstad, Gunnar A1 - Schöning, Michael Josef T1 - Monitoring the microbicidal effectiveness of gaseous hydrogen peroxide in sterilisation processes by means of a calorimetric gas sensor JF - Food control N2 - In the present work, a novel method for monitoring sterilisation processes with gaseous H2O2 in combination with heat activation by means of a specially designed calorimetric gas sensor was evaluated. Therefore, the sterilisation process was extensively studied by using test specimens inoculated with Bacillus atrophaeus spores in order to identify the most influencing process factors on its microbicidal effectiveness. Besides the contact time of the test specimens with gaseous H2O2 varied between 0.2 and 0.5 s, the present H2O2 concentration in a range from 0 to 8% v/v (volume percent) had a strong influence on the microbicidal effectiveness, whereas the change of the vaporiser temperature, gas flow and humidity were almost negligible. Furthermore, a calorimetric H2O2 gas sensor was characterised in the sterilisation process with gaseous H2O2 in a wide range of parameter settings, wherein the measurement signal has shown a linear response against the H2O2 concentration with a sensitivity of 4.75 °C/(% v/v). In a final step, a correlation model by matching the measurement signal of the gas sensor with the microbial inactivation kinetics was established that demonstrates its suitability as an efficient method for validating the microbicidal effectiveness of sterilisation processes with gaseous H2O2. KW - hydrogen peroxide KW - sterilisation KW - Bacillus atrophaeus KW - calorimetric gas sensor Y1 - 2012 U6 - http://dx.doi.org/10.1016/j.foodcont.2012.11.048 SN - 0956-7135 VL - 31 IS - 2 SP - 530 EP - 538 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Kirchner, Patrick A1 - Oberländer, Jan A1 - Friedrich, Peter A1 - Rysstad, G. A1 - Berger, J. A1 - Keusgen, M. A1 - Schöning, Michael Josef T1 - Realization of a calorimetric gas sensor on polyimide foil for applications in aseptic food industry JF - Procedia Engineering. 5 (2010) Y1 - 2010 SN - 1877-7058 N1 - Eurosensor XXIV Conference SP - 264 EP - 267 ER - TY - JOUR A1 - Kirchner, Patrick A1 - Oberländer, Jan A1 - Friedrich, Peter A1 - Berger, Jörg A1 - Suso, Henri-Pierre A1 - Kupyna, Andriy A1 - Keusgen, Michael A1 - Schöning, Michael Josef T1 - Optimisation and fabrication of a calorimetric gas sensor built up on a polyimide substrate for H2O2 monitoring JF - Physica status solidi (a) : applications and material science. 208 (2011), H. 6 Y1 - 2011 SN - 1862-6319 SP - 1235 EP - 1240 PB - Wiley CY - Weinheim ER - TY - JOUR A1 - Kirchner, Patrick A1 - Oberländer, Jan A1 - Friedrich, Peter A1 - Berger, Jörg A1 - Rysstad, Gunnar A1 - Schöning, Michael Josef A1 - Keusgen, Michael T1 - Realisation of a calorimetric gas sensor on polyimide foil for applications in aseptic food industry JF - Sensors and Actuators B: Chemical N2 - A calorimetric gas sensor is presented for the monitoring of vapour-phase H2O2 at elevated temperature during sterilisation processes in aseptic food industry. The sensor was built up on a flexible polyimide foil (thickness: 25 μm) that has been chosen due to its thermal stability and low thermal conductivity. The sensor set-up consists of two temperature-sensitive platinum thin-film resistances passivated by a layer of SU-8 photo resist and catalytically activated by manganese(IV) oxide. Instead of an active heating structure, the calorimetric sensor utilises the elevated temperature of the evaporated H2O2 aerosol. In an experimental test rig, the sensor has shown a sensitivity of 4.78 °C/(%, v/v) in a H2O2 concentration range of 0%, v/v to 8%, v/v. Furthermore, the sensor possesses the same, unchanged sensor signal even at varied medium temperatures between 210 °C and 270 °C of the gas stream. At flow rates of the gas stream from 8 m3/h to 12 m3/h, the sensor has shown only a slightly reduced sensitivity at a low flow rate of 8 m3/h. The sensor characterisation demonstrates the suitability of the calorimetric gas sensor for monitoring the efficiency of industrial sterilisation processes. KW - Sterilisation process KW - Hydrogen peroxide KW - Polyimide KW - Calorimetric gas sensor Y1 - 2012 U6 - http://dx.doi.org/10.1016/j.snb.2011.01.032 SN - 0925-4005 N1 - Part of special issue "Eurosensors XXIV, 2010" VL - 170 SP - 60 EP - 66 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Kirchner, Patrick A1 - Li, Bin A1 - Spelthahn, Heiko A1 - Henkel, Hartmut A1 - Schneider, Andreas A1 - Friedrich, Peter A1 - Kolstad, Jens A1 - Keusgen, Michael A1 - Schöning, Michael Josef T1 - Thin-film calorimetric H2O2 gas sensor for the validation of germicidal effectivity in aseptic filling processes JF - Sensors and Actuators B: Chemical. 154 (2011), H. 2 Y1 - 2011 SN - 1873-3077 N1 - EUROSENSORS XXIII SP - 257 EP - 263 PB - Elsevier CY - Amsterdam ER -