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 - Spelthahn, Heiko A1 - Kirsanov, Dmitry A1 - Legin, Andrey A1 - Osterrath, Thomas A1 - Schubert, Jürgen A1 - Zander, Willi A1 - Schöning, Michael Josef T1 - Development of a thin-film sensor array for analytical monitoring of heavy metals in aqueous solutions JF - Physica Status Solidi (a) N2 - In industrial processes there is a variety of heavy metals (e.g., copper, zinc, cadmium, and lead) in use for wires, coatings, paints, alloys, batteries, etc. Since the application of these transition metals for industry is inevitable, it is a vital task to develop proper analytical techniques for their monitoring at low activity levels, especially because most of these elements are acutely toxic for biological organisms. The determination of ions in solution by means of a simple and inexpensive sensor array is, therefore, a promising task. In this work, a sensor array with heavy metal-sensitive chalcogenide glass membranes for the simultaneous detection of the four ions Ag⁺, Cu2⁺, Cd2⁺, and Pb2⁺ in solution is realized. The results of the physical characterization by means of microscopy, profilometry, Rutherford backscattering spectroscopy (RBS), and scanning electron microscopy (SEM) as well as the electrochemical characterization by means of potentiometric measurements are presented. Additionally, the possibility to expand the sensor array by polymeric sensor membranes is discussed. Y1 - 2012 SN - 1862-6319 U6 - http://dx.doi.org/10.1002/pssa.201100733 VL - 209 IS - 5 SP - 885 EP - 891 PB - Wiley-VCH CY - Weinheim 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 - Svetlova, O. V. A1 - Stegaev, V. A. A1 - Parkhomov, S. D. T1 - Biomechanical substantiation of relatively low efficiency of recurrent laser trabeculoplasty / Svetlova, O. V. ; Stagaev, V. A. ; Parkhomov, S. D. ; Kotliar, K. E. ; Makarov, F. N. ; Smolnikov, B. A. ; Koshitz, I. N. JF - Glaukoma (2004) Y1 - 2004 N1 - Original in Russisch SP - 29 EP - 39 PB - - ER - TY - JOUR A1 - Kotliar, Konstantin A1 - Svetlova, O. V. A1 - Sourjikov, A. V. A1 - Zaseeva, M. V. T1 - Biomechanical peculiarities of aqueous humor production system and outflow regulation system / Svetlova, O. V. ; Sourjikov, A. V. ; Kotliar, K. E. ; Zaseeva, M. V. ; Shukhaev, S. V. ; Koshitz, I. N. JF - Glaukoma (2004) Y1 - 2004 N1 - Original in Russisch SP - 66 EP - 76 PB - - ER - TY - JOUR A1 - Miyamoto, Ko-ichiro A1 - Kaneko, Kazumi A1 - Matsuo, Akira A1 - Wagner, Torsten A1 - Kanoh, Shiníchiro A1 - Schöning, Michael Josef A1 - Yoshinobu, Tatsuo T1 - Miniaturized chemical imaging sensor system using an OLED display panel JF - Sensors and Actuators B: Chemical N2 - The chemical imaging sensor is a semiconductor-based chemical sensor that can visualize the two-dimensional distribution of specific ions or molecules in the solution. In this study, we developed a miniaturized chemical imaging sensor system with an OLED display panel as a light source that scans the sensor plate. In the proposed configuration, the display panel is placed directly below the sensor plate and illuminates the back surface. The measured area defined by illumination can be arbitrarily customized to fit the size and the shape of the sample to be measured. The waveform of the generated photocurrent, the current–voltage characteristics and the pH sensitivity were investigated and pH imaging with this miniaturized system was demonstrated. KW - LAPS KW - Light-addressable potentiometric sensor KW - Chemical imaging sensor KW - Organic light-emitting diode display Y1 - 2012 U6 - http://dx.doi.org/10.1016/j.snb.2011.02.029 SN - 0925-4005 N1 - Part of special issue "Eurosensors XXIV, 2010" VL - 170 SP - 82 EP - 87 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Schusser, Sebastian A1 - Poghossian, Arshak A1 - Bäcker, Matthias A1 - Leinhos, Marcel A1 - Wagner, Patrick A1 - Schöning, Michael Josef T1 - Characterization of biodegradable polymers with capacitive field-effect sensors JF - Sensors and actuators B: Chemical N2 - In vitro studies of the degradation kinetic of biopolymers are essential for the design and optimization of implantable biomedical devices. In the presented work, a field-effect capacitive sensor has been applied for the real-time and in situ monitoring of degradation processes of biopolymers for the first time. The polymer-covered field-effect sensor is, in principle, capable to detect any changes in bulk, surface and interface properties of the polymer induced by degradation processes. The feasibility of this approach has been experimentally proven by using the commercially available biomedical polymer poly(D,L-lactic acid) (PDLLA) as a model system. PDLLA films of different thicknesses were deposited on the Ta₂O₅-gate surface of the field-effect structure from a polymer solution by means of spin-coating method. The polymer-modified field-effect sensors have been characterized by means of capacitance–voltage and impedance-spectroscopy method. The degradation of the PDLLA was accelerated by changing the degradation medium from neutral (pH 7.2) to alkaline (pH 9) condition, resulting in drastic changes in the capacitance and impedance spectra of the polymer-modified field-effect sensor. KW - Impedance spectroscopy KW - C–V method KW - Real-time monitoring KW - Poly(d,l-lacticacid) KW - (Bio)degradation KW - Field-effect sensor Y1 - 2012 U6 - http://dx.doi.org/10.1016/j.snb.2012.07.099 SN - 0925-4005 N1 - Part of special issue "Selected Papers from the 14th International Meeting on Chemical Sensors" VL - 187 SP - 2 EP - 7 PB - Elsevier CY - Amsterdam 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 - Atlas, Glen A1 - Brealey, David A1 - Dhar, Sunil A1 - Dikta, Gerhard A1 - Singer, Meryvn T1 - Additional hemodynamic measurements with an esophageal Doppler monitor: a preliminary report of compliance, force, kinetic energy, and afterload in the clinical setting JF - Journal of clinical monitoring and computing N2 - The esophageal Doppler monitor (EDM) is a minimally-invasive hemodynamic device which evaluates both cardiac output (CO), and fluid status, by estimating stroke volume (SV) and calculating heart rate (HR). The measurement of these parameters is based upon a continuous and accurate approximation of distal thoracic aortic blood flow. Furthermore, the peak velocity (PV) and mean acceleration (MA), of aortic blood flow at this anatomic location, are also determined by the EDM. The purpose of this preliminary report is to examine additional clinical hemodynamic calculations of: compliance (C), kinetic energy (KE), force (F), and afterload (TSVRi). These data were derived using both velocity-based measurements, provided by the EDM, as well as other contemporaneous physiologic parameters. Data were obtained from anesthetized patients undergoing surgery or who were in a critical care unit. A graphical inspection of these measurements is presented and discussed with respect to each patient’s clinical situation. When normalized to each of their initial values, F and KE both consistently demonstrated more discriminative power than either PV or MA. The EDM offers additional applications for hemodynamic monitoring. Further research regarding the accuracy, utility, and limitations of these parameters is therefore indicated. KW - Acceleration KW - Velocity KW - Kinetic energy KW - Force KW - Compliance KW - Afterload KW - Contractility KW - Volume status KW - Esophageal Doppler monitor Y1 - 2012 SN - 1573-2614 U6 - http://dx.doi.org/10.1007/s10877-012-9386-5 IS - 26 SP - 473 EP - 482 PB - Springer Nature CY - London ER - TY - JOUR A1 - Digel, Ilya T1 - Primary thermosensory events in cells JF - Transient receptor potential channels / Md. Shahidul Islam, ed. Y1 - 2011 SN - 978-94-007-0264-6 N1 - (Advances in experimental medicine and biology ; 704) SP - 451 EP - 468 PB - Springer CY - Dordrecht [u.a.] ER - TY - JOUR A1 - Digel, Ilya A1 - Temiz Artmann, Aysegül T1 - The emperor's new body : seeking for a blueprint of limb regeneration in humans JF - Stem cell engineering : principles and applications / Gerhard M. Artmann ... eds. Y1 - 2011 SN - 978-3-642-11864-7 SP - 3 EP - 37 PB - Springer CY - Berlin [u.a.] ER - TY - BOOK A1 - Artmann, Gerhard T1 - Stem cell engineering : principles and applications / Gerhard M. Artmann ... eds. Y1 - 2011 SN - 978-3-642-11864-7 PB - Springer CY - Berlin [u.a.] ER - TY - JOUR A1 - Digel, Ilya T1 - Controlling microbial adhesion : a surface engineering approach JF - Bioengineering in Cell and Tissue Research / Artmann, Gerhard M. ; Chien, Shu (Eds.) Y1 - 2008 SN - 978-3-540-75408-4 SP - 601 EP - 625 PB - Springer CY - Berlin [u.a.] ER - TY - JOUR A1 - Bassam, Rasha A1 - Hescheler, Jürgen A1 - Temiz Artmann, Aysegül A1 - Artmann, Gerhard A1 - Digel, Ilya T1 - Effects of spermine NONOate and ATP on the thermal stability of hemoglobin JF - BMC Biophysics N2 - Background Minor changes in protein structure induced by small organic and inorganic molecules can result in significant metabolic effects. The effects can be even more profound if the molecular players are chemically active and present in the cell in considerable amounts. The aim of our study was to investigate effects of a nitric oxide donor (spermine NONOate), ATP and sodium/potassium environment on the dynamics of thermal unfolding of human hemoglobin (Hb). The effect of these molecules was examined by means of circular dichroism spectrometry (CD) in the temperature range between 25°C and 70°C. The alpha-helical content of buffered hemoglobin samples (0.1 mg/ml) was estimated via ellipticity change measurements at a heating rate of 1°C/min. Results Major results were: 1) spermine NONOate persistently decreased the hemoglobin unfolding temperature T u irrespectively of the Na + /K + environment, 2) ATP instead increased the unfolding temperature by 3°C in both sodium-based and potassium-based buffers and 3) mutual effects of ATP and NO were strongly influenced by particular buffer ionic compositions. Moreover, the presence of potassium facilitated a partial unfolding of alpha-helical structures even at room temperature. Conclusion The obtained data might shed more light on molecular mechanisms and biophysics involved in the regulation of protein activity by small solutes in the cell. KW - Nitric Oxide Donor KW - NONOate KW - Circular Dichroism KW - Nitric Oxide Y1 - 2012 U6 - http://dx.doi.org/10.1186/2046-1682-5-16 SN - 2046-1682 VL - 5 PB - BioMed Central CY - London ER - TY - JOUR A1 - Stadler, Andreas M. A1 - Digel, Ilya A1 - Embs, Jan P. A1 - Unruh, Tobias A1 - Tehei, M. A1 - Zaccai, G. A1 - Büldt, G. A1 - Artmann, Gerhard T1 - From powder to solution : Hydration dependence of human hemoglobin dynamics correlated to body temperature JF - Biophysical Journal. 96 (2009), H. 12 Y1 - 2009 SN - 0006-3495 SP - 5073 EP - 5081 PB - Cell Press CY - Cambridge, Mass. ER - TY - JOUR A1 - Stadler, Andreas M. A1 - Embs, Jan P. A1 - Digel, Ilya A1 - Artmann, Gerhard A1 - Unruh, Tobias A1 - Büldt, Georg A1 - Zaccai, Guiseppe T1 - Cytoplasmic water and hydration layer dynamics in human red blood cells JF - Journal of the American Chemical Society. 50 (2008), H. 130 Y1 - 2008 SN - 1520-5126 SP - 16852 EP - 16853 ER - TY - JOUR A1 - Digel, Ilya A1 - Kayser, Peter A1 - Artmann, Gerhard T1 - Molecular processes in biological thermosensation JF - Journal of Biophysics. 2008 (2008) Y1 - 2008 SN - 1687-8000 SP - 1 EP - 9 ER - TY - JOUR A1 - Kotliar, Konstantin A1 - Svetlova, O. V. A1 - Makarov, F. N. A1 - Zaseeva, M. V. T1 - Morfologicheskie i funktsional'nye osobennosti resnichnogo poiaska khrustalika kak kliuchevogo ispolnitel'nogo zvena v mekhanizme akkommodatsii glaza cheloveka = Morpho-functional characteristics of lens ciliary body as a key mechanism of accommodation in JF - Morfologiia (Saint Petersburg, Russia). 123 (2003), H. 3 Y1 - 2003 SN - 1026-3543 N1 - Original in Russisch, English abstract SP - 7 EP - 16 PB - - ER - TY - JOUR A1 - Kotliar, Konstantin A1 - Volkov, V. V. A1 - Koshits, I. N. A1 - Svetlova, O. V. T1 - Biomekhanicheskie osobennosti vzaimodeĭstviia drenazhno i akkomodatsionnoĭ reguliatornykh sistem glaza v norme i pri kontuzionnom podvyvikhe khrustalika / Volkov, V. V. ; Kotliar, K. E. ; Koshits, I. n. ; Svetlova, O. V. ; Smol´nikov, B. A. JF - Vestnik oftalmologii. 113 (1997), H. 3 Y1 - 1997 SN - 0042-465X N1 - Titelübersetzung: Biomechanical characteristics of interactions between the drainage and accommodation regulatory systems of the eye in health and in contusion lens subluxation ; Original in Russisch, English abstract SP - 5 EP - 7 PB - - ER - TY - JOUR A1 - Mikielewicz, Marek A1 - Kotliar, Konstantin A1 - Barraquer, Rafael I. A1 - Michael, Ralph T1 - Air-pulse corneal applanation signal curve parameters for the characterisation of keratoconus JF - British Journal of Ophthalmology (eBJO) Y1 - 2011 SN - 1468-2079 VL - 95 IS - 6 SP - 793 EP - 798 PB - BMJ Publ. Group CY - London 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 - 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 - Dashevsky, Alexey V. A1 - Lanzl, Ines M. A1 - Kotliar, Konstantin T1 - Non-penetrating intracanalicular partial trabeculectomy via the ostia of Schlemm's canal JF - Graefe's Archive for Clinical and Experimental Ophthalmology Y1 - 2011 SN - 0721-832x VL - 249 IS - 4 SP - 565 EP - 573 PB - Springer CY - Berlin ER - TY - JOUR A1 - Baumann, Marcus A1 - Schwarz, Sonja A1 - Kotliar, Konstantin A1 - Eynatten, Maximilian von A1 - Trucksaess, Arno A1 - Burckhardt, Klaus A1 - Lutz, Jens A1 - Heemann, Uwe A1 - Lanzl, Ines T1 - Non-diabetic chronic kidney disease influences retinal microvasculature JF - Kidney and Blood Pressure Research Y1 - 2009 SN - 1423-0143 VL - 32 IS - 6 SP - 428 EP - 433 PB - - ER - TY - JOUR A1 - Burkhardt, Klaus A1 - Schwarz, Sonja A1 - Pan, Chengrui A1 - Stelter, Felix A1 - Kotliar, Konstantin A1 - Eynatten, Maxilian von A1 - Sollinger, Daniel A1 - Lanzl, Ines A1 - Heemann, Uwe A1 - Baumann, Marcus T1 - Myeloid-related protein 8/14 complex describes microcirculatory alterations in patients with type 2 diabetes and nephropathy JF - Cardiovascular Diabetology Y1 - 2009 SN - 1475-2840 VL - 8 IS - 10 SP - 1 EP - 8 PB - - ER - TY - JOUR A1 - Gutheil, Inge A1 - Berg, Tommy A1 - Grotendorst, Johannes T1 - Performance Analysis of Parallel Eigensolvers of two Libraries on BlueGene/P JF - Journal of Mathematics and Systems Science N2 - Many applications in computational science and engineering require the computation of eigenvalues and vectors of dense symmetric or Hermitian matrices. For example, in DFT (density functional theory) calculations on modern supercomputers 10% to 30% of the eigenvalues and eigenvectors of huge dense matrices have to be calculated. Therefore, performance and parallel scaling of the used eigensolvers is of upmost interest. In this article different routines of the linear algebra packages ScaLAPACK and Elemental for parallel solution of the symmetric eigenvalue problem are compared concerning their performance on the BlueGene/P supercomputer. Parameters for performance optimization are adjusted for the different data distribution methods used in the two libraries. It is found that for all test cases the new library Elemental which uses a two-dimensional element by element distribution of the matrices to the processors shows better performance than the old ScaLAPACK library which uses a block-cyclic distribution. KW - performance analysis KW - Elemental KW - ScaLAPACK KW - eigensolvers KW - Numerical linear algebra Y1 - 2012 U6 - http://dx.doi.org/10.17265/2159-5291/2012.04.003 SN - 2159-5291 VL - 2 IS - 4 SP - 231 EP - 236 PB - David Publishing CY - Libertyville ER - TY - JOUR A1 - Grotendorst, Johannes T1 - IAS Winter School: Hierarchical Methods for Dynamics in Complex Molecular Systems JF - Innovatives Supercomputing in Deutschland : inSiDE. 10 (2012), H. 1 Y1 - 2012 SP - 104 PB - - 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 - Seidova, Seid-Fatima A1 - Kotliar, Konstantin A1 - Foerger, Frauke A1 - Klopfer, Matthias A1 - Lanzl, Ines T1 - Functional retinal changes in Gaucher disease JF - Documenta Ophthalmologica Y1 - 2009 SN - 1573-2622 VL - 118 IS - 2 SP - 151 EP - 154 PB - Springer CY - Berlin 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 - Vilser, Walthatd A1 - Nagel, Edgar A1 - Lanzl, Ines M. T1 - Retinal vessel reaction in response to chromatic flickering light / Kotliar, Konstantin E. ; Vilser, Walthard ; Nagel, Edgar ; Lanzl, Ines M. JF - Graefe's Archive for Clinical and Experimental Ophthalmology. 242 (2004), H. 5 Y1 - 2004 SN - 1435-702X SP - 377 EP - 392 PB - - 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 - JOUR A1 - Kotliar, Konstantin A1 - Svetlova, O. V. A1 - Zinoviewa, N. V. A1 - Krylova, I. S. T1 - Elaboration of the conception of the biomechanical model of the aqueous intraocular outflow / Svetlova, O. V. ; Zinoviewa, N. V. ; Krylova, I. S. ; Koshitz, I. N. ; Smolnikov, B. A. ; Fedorova, E. M. ; Kotliar, K. E. JF - Rossiiskii zhurnal biomekhaniki = Russian Journal of biomechanics. 5 (2001), H. 3 Y1 - 2001 SN - 1812-5123 SP - 23 EP - 27 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 - 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 - Lanzl, Ines M. A1 - Seidova, Seid-Fatima A1 - Maier, Mathias A1 - Schmidt-Trucksäss, Arno A1 - Halle, Martin A1 - Kotliar, Konstantin T1 - Dynamic retinal vessel response to flicker in age-related macular degeneration patients before and after vascular endothelial growth factor inhibitor injection JF - Acta Ophthalmologica Y1 - 2011 SN - 1755-3768 VL - 89 IS - 5 SP - 472 EP - 479 PB - Wiley CY - Weinheim 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 - 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 - 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 - 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 - Zerlin, Kay A1 - Digel, Ilya A1 - Stadler, Andreas M. A1 - Büldt, Georg A1 - Zaccai, Guiseppe A1 - Artmann, Gerhard T1 - Dynamics and interactions of hemoglobin in human red blood cells and concentrated hemoglobin solutions JF - Regenerative medicine. 2 (2007), H. 5 Y1 - 2007 SN - 1746-0751 N1 - Proceedings of the 3rd World Congress on Regenerative Medicine. October 18-20, 2007. Leipzig, Germany SP - 573 EP - 573 ER - TY - JOUR A1 - Digel, Ilya A1 - Zerlin, Kay A1 - Temiz Artmann, Aysegül A1 - Engels, S. T1 - Protein dynamics in thermosensation JF - Regenerative medicine. 2 (2007), H. 5 Y1 - 2007 SN - 1746-0751 N1 - Proceedings of the 3rd World Congress on Regenerative Medicine. October 18-20, 2007. Leipzig, Germany SP - 533 EP - 533 ER - TY - JOUR A1 - Zerlin, Kay A1 - Kasischke, Nicole A1 - Digel, Ilya A1 - Maggakis-Kelemen, Christina A1 - Temiz Artmann, Aysegül A1 - Porst, Dariusz A1 - Kayser, Peter A1 - Linder, Peter A1 - Artmann, Gerhard T1 - Structural transition temperature of hemoglobins correlates with species’ body temperature JF - European Biophysics Journal. 37 (2007), H. 1 Y1 - 2007 SN - 1432-1017 SP - 1 EP - 10 ER - TY - JOUR A1 - Digel, Ilya A1 - Kurulgan Demirci, Eylem A1 - Linder, Peter A1 - Kayser, Peter T1 - Decrease in extracellular collagen crosslinking after NMR magnetic field application in skin fibroblasts JF - Medical and Biological Engineering and Computing. 45 (2007), H. 1 Y1 - 2007 SN - 1741-0444 SP - 91 EP - 97 ER - TY - JOUR A1 - Digel, Ilya A1 - Maggakis-Kelemen, Christina A1 - Zerlin, Kay A1 - Linder, Peter T1 - Body temperature-related structural transitions of monotremal and human hemoglobin JF - Biophysical Journal. 91 (2006), H. 8 Y1 - 2006 SN - 1542-0086 SP - 3014 EP - 3021 ER - TY - JOUR A1 - Digel, Ilya A1 - Temiz Artmann, Aysegül A1 - Nishikawa, K. A1 - Cook, M. T1 - Bactericidal effects of plasma-generated cluster ions JF - Medical and Biological Engineering and Computing. 43 (2005), H. 6 Y1 - 2005 SN - 1741-0444 SP - 800 EP - 807 ER - TY - JOUR A1 - Trzewik, Jürgen A1 - Temiz Artmann, Aysegül A1 - Linder, Peter A1 - Demirci, T. A1 - Digel, Ilya A1 - Artmann, Gerhard T1 - Evaluation of lateral mechanical tension in thin-film tissue constructs JF - Annals of Biomedical Engineering. 32 (2004), H. 9 Y1 - 2004 SN - 1573-9686 SP - 1243 EP - 1251 ER - TY - JOUR A1 - Bogoyavlenskiy, A. P. A1 - Berezin, V. E. A1 - Ogneva, A. V. A1 - Tolmacheva, V. P. A1 - Digel, Ilya A1 - Khudyakova, S. S. T1 - Immunostimulating activity of a saponin-containing extract of Saponaria officinalis JF - Voprosy virusologii Y1 - 1999 SN - 0507-4088 VL - 44 IS - 5 SP - 229 EP - 232 ER - TY - JOUR A1 - Digel, Ilya A1 - Trzewik, Jürgen A1 - Demirci, Taylan A1 - Temiz Artmann, Aysegül T1 - Response of fibroblasts to cyclic mechanical stress : a proteome approach / Digel, I. ; Trzewik, J. ; Demirci, T. ; Temiz Artmann, A. ; Artmann, G. M. JF - Biomedizinische Technik. 49 (2004), H. Erg.-Bd. 2 Y1 - 2004 SN - 0932-4666 SP - 1042 EP - 1043 ER - TY - JOUR A1 - Digel, Ilya A1 - Demirci, Taylan A1 - Temiz Artmann, Aysegül A1 - Nishikawa, K. T1 - Free Radical Nature of the Bactericidal Effect of Plasma-Generated Cluster Ions (PCIs) JF - Biomedizinische Technik. 49 (2004), H. Erg.-Bd. 2 Y1 - 2004 SN - 0932-4666 SP - 982 EP - 983 ER - TY - JOUR A1 - Bohrn, Ulrich A1 - Stütz, Evamaria A1 - Fleischer, Maximilian A1 - Schöning, Michael Josef A1 - Wagner, Patrick T1 - Using a cell-based gas biosensor for investigation of adverse effects of acetone vapors in vitro JF - Biosensors and Bioelectronics. 40 (2013), H. 1 Y1 - 2013 SN - 0956-5663 SP - 393 EP - 400 PB - Elsevier CY - Amsterdam 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 - BOOK A1 - Grotendorst, Johannes T1 - Hierarchical methods for dynamics in complex molecular systems : IAS Winter School, 5 - 9 March 2012, Forschungszentrum Jülich GmbH ; lecture notes / ed. by Johannes Grotendorst, Godehard Sutmann, Gerhard Gompper, Dominik Marx Y1 - 2012 SN - 978-3-89336-768-9 N1 - (Schriften des Forschungszentrums Jülich IAS Series 10) PB - Forschungszentrum Jülich CY - Jülich ER - TY - JOUR A1 - Digel, Ilya A1 - Temiz Artmann, Aysegül A1 - Nishikawa, K. A1 - Artmann, Gerhard T1 - Cluster air-ion effects on bacteria and moulds JF - Biomedizinische Technik. 49 (2004), H. Erg.-Bd. 2 Y1 - 2004 SN - 0932-4666 SP - 1040 EP - 1041 ER - TY - JOUR A1 - Maggakis-Kelemen, Christina A1 - Digel, Ilya A1 - Artmann, Gerhard T1 - Polystyrene sulfonate/Polyallylamine hydrochloride microcapsules as potential artificial red blood cells - improvement of capsule flexibility JF - Biomedizinische Technik. 50 (2005), H. Erg.-Bd. 1 Y1 - 2005 SP - 324 EP - 326 ER - TY - JOUR A1 - Stadler, Andreas M. A1 - Zerlin, Kay A1 - Digel, Ilya A1 - Büldt, Georg A1 - Zaccai, Guiseppe A1 - Artmann, Gerhard T1 - Dynamics and interactions of hemoglobin in red blood cells JF - Tissue Engineering Part A. 14 (2008), H. 5 Y1 - 2008 SN - 1937-3341 N1 - TERMIS EU 2008 Porto Meeting June 22–26, 2008 Porto Congress Center–Alfândega Portugal SP - 724 EP - 724 ER - TY - JOUR A1 - Kurulgan Demirci, Eylem A1 - Linder, Peter A1 - Demirci, Taylan A1 - Trzewik, Jürgen A1 - Digel, Ilya A1 - Artmann, Gerhard A1 - Temiz Artmann, Aysegül T1 - Contractile tension of endothelial cells: An LPS based in-vitro sepsis model JF - IUBMB Life. 61 (2009), H. 3 Y1 - 2009 SN - 1521-6543 N1 - Abstracts: Turkish Society of Molecular Medicine, Third International Congress of Molecular Medicine, May 5-8, 2009, Istanbul, Turkey SP - 307 EP - 308 PB - Wiley CY - Weinheim ER - TY - JOUR A1 - Artmann, Gerhard A1 - Digel, Ilya A1 - Linder, Peter A1 - Porst, Dariusz T1 - Mechanism of haemoglobin sensing body temperature JF - Tissue Engineering Part A. 14 (2008), H. 5 Y1 - 2008 SN - 1937-3341 N1 - TERMIS EU 2008 Porto Meeting June 22–26, 2008 Porto Congress Center–Alfândega Portugal SP - 754 EP - 754 ER - TY - JOUR A1 - Artmann, Gerhard A1 - Zerlin, Kay A1 - Digel, Ilya A1 - Stadler, Andreas M. T1 - Physical discontinuities at body temperature in human red blood cells / Artmann, GM ; Zerlin, K ; Digel, I ; Stadler, A ; Zaccai, G ; Temiz, AA JF - Tissue Engineering. 13 (2007), H. 7 Y1 - 2007 SN - 1076-3279 N1 - TERMIS-EU Meeting Abstracts London, UK September 4–7, 2007 SP - 1778 EP - 1778 ER - TY - CHAP A1 - Digel, Ilya A1 - Mansurov, Zulkhair A1 - Biisenbaev, Makhmut A1 - Savitskaya, Irina A1 - Kistaubaeva, Aida A1 - Akimbekov, Nuraly A1 - Zhubanova, Azhar ED - Hu, Ning T1 - Heterogeneous Composites on the Basis of Microbial Cells and Nanostructured Carbonized Sorbents T2 - Composites and Their Applications N2 - The fact that microorganisms prefer to grow on liquid/solid phase surfaces rather than in the surrounding aqueous phase was noticed long time ago [1]. Virtually any surface – animal, mineral, or vegetable – is a subject for microbial colonization and subsequent biofilm formation. It would be adequate to name just a few notorious examples on microbial colonization of contact lenses, ship hulls, petroleum pipelines, rocks in streams and all kinds of biomedical implants. The propensity of microorganisms to become surface-bound is so profound and ubiquitous that it vindicates the advantages for attached forms over their free-ranging counterparts [2]. Indeed, from ecological and evolutionary standpoints, for many microorganisms the surface-bound state means dwelling in nutritionally favorable, non-hostile environments [3]. Therefore, in most of natural and artificial ecosystems surface-associated microorganisms vastly outnumber organisms in suspension and often organize into complex communities with features that differ dramatically from those of free cells [4]. Y1 - 2012 SN - 978-953-51-0706-4 U6 - http://dx.doi.org/10.5772/47796 SP - 249 EP - 272 PB - Intech CY - London ER - TY - JOUR A1 - Murib, Mohammed S. A1 - Tran, Anh Quang A1 - Ceuninck, Ward de A1 - Schöning, Michael Josef A1 - Nesladek, Milos A1 - Serpengüzel, Ali A1 - Wagner, Patrick T1 - Analysis of an optical biosensor based on elastic light scattering from diamond-, glass-, and sapphire microspheres JF - Physica Status Solidi A N2 - Deoxyribonucleic acid (DNA) and protein recognition are now standard tools in biology. In addition, the special optical properties of microsphere resonators expressed by the high quality factor (Q-factor) of whispering gallery modes (WGMs) or morphology dependent resonances (MDRs) have attracted the attention of the biophotonic community. Microsphere-based biosensors are considered as powerful candidates to achieve label-free recognition of single molecules due to the high sensitivity of their WGMs. When the microsphere surface is modified with biomolecules, the effective refractive index and the effective size of the microsphere change resulting in a resonant wavelength shift. The transverse electric (TE) and the transverse magnetic (TM) elastic light scattering intensity of electromagnetic waves at 600 and 1400 nm are numerically calculated for DNA and unspecific binding of proteins to the microsphere surface. The effect of changing the optical properties was studied for diamond (refractive index 2.34), glass (refractive index 1.50), and sapphire (refractive index 1.75) microspheres with a 50 µm radius. The mode spacing, the linewidth of WGMs, and the shift of resonant wavelength due to the change in radius and refractive index, were analyzed by numerical simulations. Preliminary results of unspecific binding of biomolecules are presented. The calculated shift in WGMs can be used for biomolecules detection. Y1 - 2012 U6 - http://dx.doi.org/10.1002/pssa.201100795 SN - 1862-6319 N1 - Special Issue: "Fundamentals and Applications of Diamond" VL - 209 IS - 9 SP - 1804 EP - 1810 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Digel, Ilya A1 - Zhubanova, Azhar A. A1 - Nojima, H. A1 - Artmann, Gerhard T1 - The use of bactericidal effects of cluster ions generated by plasma in medical biotechnology JF - Biotechnologija : teorija i praktika (2004) Y1 - 2004 SN - 1028-9399 SP - 46 EP - 52 ER - TY - JOUR A1 - Iken, Heiko A1 - Kirsanov, D. A1 - Legin, A. A1 - Schöning, Michael Josef T1 - Novel Thin-Film Polymeric Materials for the Detection of Heavy Metals JF - Procedia Engineering N2 - A variety of transition metals, e.g., copper, zinc, cadmium, lead, etc. are widely used in industry as components for wires, coatings, alloys, batteries, paints and so on. The inevitable presence of transition metals in industrial processes implies the ambition of developing a proper analytical technique for their adequate monitoring. Most of these elements, especially lead and cadmium, are acutely toxic for biological organisms. Quantitative determination of these metals at low activity levels in different environmental and industrial samples is therefore a vital task. A promising approach to achieve an at-side or on-line monitoring on a miniaturized and cost efficient way is the combination of a common potentiometric sensor array with heavy metal-sensitive thin-film materials, like chalcogenide glasses and polymeric materials, respectively. Y1 - 2012 U6 - http://dx.doi.org/10.1016/j.proeng.2012.09.148 SN - 1877-7058 N1 - Part of special issue "26th European Conference on Solid-State Transducers, EUROSENSOR 2012" IS - 47 SP - 322 EP - 325 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Miyamoto, K. A1 - Ichimura, H. A1 - Wagner, Torsten A1 - Yoshinobu, T. A1 - Schöning, Michael Josef T1 - Chemical Imaging of ion Diffusion in a Microfluidic Channel JF - Procedia Engineering N2 - The chemical imaging sensor is a chemical sensor which is capable of visualizing the spatial distribution of chemical species in sample solution. In this study, a novel measurement system based on the chemical imaging sensor was developed to observe the inside of a Y-shaped microfluidic channel while injecting two sample solutions from two branches. From the collected chemical images, it was clearly observed that the injected solutions formed laminar flows in the microfluidic channel. In addition, ion diffusion across the laminar flows was observed. This label-free method can acquire quantitative data of ion distribution and diffusion in microfluidic devices, which can be used to determine the diffusion coefficients, and therefore, the molecular weights of chemical species in the sample solution. Y1 - 2012 U6 - http://dx.doi.org/10.1016/j.proeng.2012.09.289 SN - 1877-7058 N1 - Part of special issue "26th European Conference on Solid-State Transducers, EUROSENSOR 2012" IS - 47 SP - 886 EP - 889 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Wagner, Torsten A1 - Shigiahara, N. A1 - Miyamoto, K. A1 - Suzurikawa, J. A1 - Finger, F. A1 - Schöning, Michael Josef A1 - Yoshinobu, T. T1 - Light-addressable Potentiometric Sensors and Light–addressable Electrodes as a Combined Sensor-and-manipulator Microsystem with High Flexibility JF - Procedia Engineering N2 - This work describes the novel combination of the light-addressable electrode (LAE) and the light-addressable potentiometric sensor (LAPS) into a microsystem set-up. Both the LAE as well as the LAPS shares the principle of addressing the active spot by means of a light beam. This enables both systems to manipulate resp. to detect an analyte with a high spatial resolution. Hence, combining both principles into a single set-up enables the active stimulation e.g., by means of electrolysis and a simultaneous observation e.g., the response of an entrapped biological cell by detection of extracellular pH changes. The work will describe the principles of both technologies and the necessary steps to integrate them into a single set-up. Furthermore, examples of application and operation of such systems will be presented. Y1 - 2012 U6 - http://dx.doi.org/10.1016/j.proeng.2012.09.290 SN - 1877-7058 N1 - Part of special issue "26th European Conference on Solid-State Transducers, EUROSENSOR 2012" IS - 47 SP - 890 EP - 893 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Poghossian, Arshak A1 - Weil, M. H. A1 - Bäcker, Matthias A1 - Mayer, D. A1 - Schöning, Michael Josef T1 - Field-effect Devices Functionalised with Gold-Nanoparticle/Macromolecule Hybrids: New Opportunities for a Label-Free Biosensing JF - Procedia Engineering N2 - Field-effect capacitive electrolyte-insulator-semiconductor (EIS) sensors functionalised with citrate-capped gold nanoparticles (AuNP) have been used for the electrostatic detection of macromolecules by their intrinsic molecular charge. The EIS sensor detects the charge changes in the AuNP/macromolecule hybrids induced by the adsorption or binding events. A feasibility of the proposed detection scheme has been exemplary demonstrated by realising EIS sensors for the detection of poly-D-lysine molecules. Y1 - 2012 U6 - http://dx.doi.org/10.1016/j.proeng.2012.09.136 SN - 1877-7058 N1 - Part of special issue "26th European Conference on Solid-State Transducers, EUROSENSOR 2012" IS - 47 SP - 273 EP - 276 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Digel, Ilya A1 - Dachwald, Bernd A1 - Artmann, Gerhard A1 - Linder, Peter A1 - Funke, O. T1 - A concept of a probe for particle analysis and life detection in icy environments Y1 - 2009 N1 - International workshop “Europa lander: science goals and experiments”, Space Research Institute (IKI), Moscow, Russia 9-13 February 2009 SP - 1 EP - 24 ER - TY - BOOK A1 - Digel, Ilya T1 - Enhancement of microbial adhesion onto solid surfaces using transition metals and water-soluble polymers : academic PhD dissertation in microbiology, Division of Applied Microbiology, Department of Microbiology, Biology Faculty, Kazakh National State University, Almaty, Kazakhstan / Ilya Digel Y1 - 1998 CY - Almaty ER - TY - JOUR A1 - Huck, Christina A1 - Poghossian, Arshak A1 - Wagner, Patrick A1 - Schöning, Michael Josef T1 - Combined amperometric/field-effect sensor for the detection of dissolved hydrogen JF - Sensors and actuators B: Chemical N2 - Real-time and reliable monitoring of the biogas process is crucial for a stable and efficient operation of biogas production in order to avoid digester breakdowns. The concentration of dissolved hydrogen (H₂) represents one of the key parameters for biogas process control. In this work, a one-chip integrated combined amperometric/field-effect sensor for monitoring the dissolved H₂ concentration has been developed for biogas applications. The combination of two different transducer principles might allow a more accurate and reliable measurement of dissolved H₂ as an early warning indicator of digester failures. The feasibility of the approach has been demonstrated by simultaneous amperometric/field-effect measurements of dissolved H₂ concentrations in electrolyte solutions. Both, the amperometric and the field-effect transducer show a linear response behaviour in the H₂ concentration range from 0.1 to 3% (v/v) with a slope of 198.4 ± 13.7 nA/% (v/v) and 14.9 ± 0.5 mV/% (v/v), respectively. Y1 - 2012 U6 - http://dx.doi.org/10.1016/j.snb.2012.10.050 SN - 0925-4005 N1 - Part of special issue "Selected Papers from the 14th International Meeting on Chemical Sensors" VL - 187 SP - 168 EP - 173 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Pham, Phu Tinh A1 - Staat, Manfred T1 - An Upper Bound Algorithm for Limit and Shakedown Analysis of Bounded Linearly Kinematic Hardening Structures JF - Limit State of Materials and Structures : Direct Methods 2. Saxcé, Géry de (Hrsg.) Y1 - 2013 SN - 978-94-007-5424-9 SP - 71 EP - 87 PB - Springer CY - Dordrecht ER - TY - JOUR A1 - Tran, Thanh Ngoc A1 - Staat, Manfred T1 - An Edge-Based Smoothed Finite Element Method for Primal-Dual Shakedown Analysis of Structures Under Uncertainties JF - Limit State of Materials and Structures : Direct Methods 2. Saxcé, Géry de (Hrsg.) Y1 - 2013 SN - 978-94-007-5424-9 SP - 89 EP - 102 PB - Springer CY - Dordrecht ER - TY - JOUR A1 - Hasan, Istabrak A1 - Keil, Ludger A1 - Staat, Manfred A1 - Wahl, Gerhard A1 - Bourauel, Christoph T1 - Determination of the frictional coefficient of the implant-antler interface : experimental approach JF - Biomedical Engineering / Biomedizinische Technik N2 - The similar bone structure of reindeer antler to human bone permits studying the osseointegration of dental implants in the jawbone. As the friction is one of the major factors that have a significant influence on the initial stability of immediately loaded dental implants, it is essential to define the frictional coefficient of the implant-antler interface. In this study, the kinetic frictional forces at the implant-antler interface were measured experimentally using an optomechanical setup and a stepping motor controller under different axial loads and sliding velocities. The corresponding mean values of the static and kinetic frictional coefficients were within the range of 0.5–0.7 and 0.3–0.5, respectively. An increase in the frictional forces with increasing applied axial loads was registered. The measurements showed an evidence of a decrease in the magnitude of the frictional coefficient with increasing sliding velocity. The results of this study provide a considerable assessment to clarify the suitable frictional coefficient to be used in the finite element contact analysis of antler specimens. Y1 - 2012 SN - 1862-278X VL - 57 IS - 5 SP - 359 EP - 363 PB - De Gruyter CY - Berlin ER - TY - JOUR A1 - Bassam, Rasha A1 - Digel, Ilya A1 - Hescheler, Jürgen A1 - Temiz Artmann, Aysegül A1 - Artmann, Gerhard T1 - Effects of spermine NONOate and ATP on protein aggregation: light scattering evidences JF - BMC Biophysics Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?10.1186/2046-1682-6-1 SN - 2046-1682 SP - 1 EP - 14 PB - BioMed Central CY - London ER - TY - CHAP A1 - Frotscher, Ralf A1 - Raatschen, Hans-Jürgen A1 - Staat, Manfred ED - Eberhardsteiner, J. T1 - Application of an edge-based smoothed finite element method on geometrically non-linear plates of non-linear material T2 - Proceedings European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS 2012) Y1 - 2012 N1 - 6th European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS 2012) Vienna, Austria, September 10-14, 2012 ER - TY - CHAP A1 - Duong, Minh Tuan A1 - Nguyen, Nhu Huynh A1 - Staat, Manfred ED - Eberhardsteiner, J. T1 - Numerical stability enhancement of modeling hyperelastic materials T2 - Proceedings European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS 2012) Y1 - 2012 N1 - 6th European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS 2012) Vienna, Austria, September 10-14, 2012 ER - TY - CHAP A1 - Tran, Thanh Ngoc A1 - Staat, Manfred ED - Eberhardsteiner, J. T1 - A primal-dual shakedown analysis of 3D structures using the face-based smoothed finite element method T2 - Proceedings European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS 2012) Y1 - 2012 N1 - 6th European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS 2012) Vienna, Austria, September 10-14, 2012 ER - TY - CHAP A1 - Pham, Phu Tinh A1 - Nguyen, Thanh Ngoc A1 - Staat, Manfred T1 - FEM based shakedown analysis of hardening structures T2 - Proceedings International Conference on Advances in Computational Mechanics (ACOME) Y1 - 2012 N1 - International Conference on Advances in Computational Mechanics (ACOME), August 14-16, 2012, Ho Chi Minh City, Vietnam SP - 870 EP - 882 ER - TY - JOUR A1 - Boecker, Henning A1 - Kuwert, Torsten A1 - Langen, Karl-J. A1 - Lange, Herwig W. A1 - Czech, Norbert A1 - Ziemons, Karl A1 - Herzog, Hans A1 - Shikare, Shekar A1 - Weindl, Anton A1 - Feinendegen, Ludwig E. T1 - SPECT with HMPAO compared to PET with FDG in Huntington disease JF - Journal of Computer Assisted Tomography Y1 - 1994 SN - 1532-3145 VL - 18 IS - 4 SP - 542 EP - 548 ER - TY - JOUR A1 - Grießmeier, M. A1 - Sonnenberg, F. A1 - Weckesser, M. A1 - Ziemons, Karl A1 - Langen, K.-J. A1 - Müller-Gärtner, H. W. T1 - Improvement of SPECT quantification in small brain structures by using experiment based recovery-coefficient corrections JF - European Journal of Nuclear Medicine Y1 - 1996 SN - 1619-7089 N1 - Abstracts ; PSu827 VL - 23 IS - 9 SP - 1238 EP - 1238 ER - TY - JOUR A1 - Langen, Karl J. A1 - Ziemons, Karl A1 - Kiwit, Jürgen C. W. A1 - Herzog, Hans A1 - Kuwert, Torsten A1 - Bock, Wolfgang A1 - Stöcklin, Gerhard A1 - Feinendegen, Ludwig E. A1 - Müller-Gärtner, Hans-W. T1 - 3-[123I]iodo-α-methyltyrosine and [methyl-11C]-L-methionine uptake in cerebral gliomas: a compara-tive study using SPECT and PET JF - Journal of Nuclear Medicine Y1 - 1997 SN - 0161-5505 VL - 38 IS - 4 SP - 517 EP - 522 ER - TY - JOUR A1 - Weckesser, Matthias A1 - Hufnagel, Andreas A1 - Ziemons, Karl A1 - Grießmeier, Martin A1 - Sonnenberg, Frank A1 - Hackländer, Thomas A1 - Langen, Karl-J. A1 - Holschbach, Markus A1 - Elger, Christian E. A1 - Müller-Gärtner, Hans-W. T1 - Effect of partial volume correction on muscarinic cholinergic receptor imaging with single-photon emission tomography in patients with temporal lobe epilepsy JF - European Journal of Nuclear Medicine N2 - Animal experiments and preliminary results in humans have indicated alterations of hippocampal muscarinic acetylcholine receptors (mAChR) in temporal lobe epilepsy. Patients with temporal lobe epilepsy often present with a reduction in hippocampal volume. The aim of this study was to investigate the influence of hippocampal atrophy on the quantification of mAChR with single photon emission tomography (SPET) in patients with temporal lobe epilepsy. Cerebral uptake of the muscarinic cholinergic antagonist [123I]4-iododexetimide (IDex) was investigated by SPET in patients suffering from temporal lobe epilepsy of unilateral (n=6) or predominantly unilateral (n=1) onset. Regions of interest were drawn on co-registered magnetic resonance images. Hippocampal volume was determined in these regions and was used to correct the SPET results for partial volume effects. A ratio of hippocampal IDex binding on the affected side to that on the unaffected side was used to detect changes in muscarinic cholinergic receptor density. Before partial volume correction a decrease in hippocampal IDex binding on the focus side was found in each patient. After partial volume no convincing differences remained. Our results indicate that the reduction in hippocampal IDex binding in patients with epilepsy is due to a decrease in hippocampal volume rather than to a decrease in receptor concentration. Y1 - 1997 SN - 1619-7089 VL - 24 IS - 9 SP - 1156 EP - 1161 ER - TY - JOUR A1 - Schmidt, Daniela A1 - Langen, Karl-J. A1 - Herzog, Hans A1 - Wirths, Jochen A1 - Holschbach, Markus A1 - Kiwit, Jürgen C. W. A1 - Ziemons, Karl A1 - Coenen, Heinz-H. A1 - Müller-Gärtner, Hans-W. T1 - Whole-body kinetics and dosimetry of L-3[123I]-iodo-α-methyltyrosine JF - European Journal of Nuclear Medicine Y1 - 1997 SN - 1619-7089 VL - 24 IS - 9 SP - 1162 EP - 1166 ER - TY - JOUR A1 - Nomdedeu, Mar Monsonis A1 - Willen, Christine A1 - Schieffer, Andre A1 - Arndt, Hartmut T1 - Temperature-dependent ranges of coexistence in a model of a two-prey-one-predator microbial food web JF - Marine Biology N2 - The objective of our study was to analyze the effects of temperature on the population dynamics of a three-species food web consisting of two prey bacteria (Pedobacter sp. and Acinetobacter johnsonii) and a protozoan predator (Tetrahymena pyriformis) as model organisms. We assessed the effects of temperature on the growth rates of all three species with the objective of developing a model with four differential equations based on the experimental data. The following hypotheses were tested at a theoretical level: Firstly, temperature changes can affect the dynamic behavior of a system by temperature-dependent parameters and interactions and secondly, food web response to temperature cannot be derived from the single species temperature response. The main outcome of the study is that temperature changes affect the parameter range where coexistence is possible within all three species. This has significant consequences on our ideas regarding the evaluation of effects of global warming. Y1 - 2012 U6 - http://dx.doi.org/10.1007/s00227-012-1966-x SN - 1432-1793 VL - 159 IS - 11 SP - 2423 EP - 2430 PB - Springer CY - Berlin ER - TY - THES A1 - Schieffer, Andre T1 - Studies on diversity and coexistence in an experimental microbial community N2 - Biodiversity and the coexistence of species have puzzled and fascinated biologists since decades and is a hotspot in todays’ natural sciences. Preserving this biodiversity is a great challenge as habitats and environments underlying tremendous changes like climate change and the loss of natural habitats, which are mainly due to anthropogenic influences. The coexistence of numerous species even in homogeneous environments is a stunning feature of natural communities and has been summarized under the term ‘paradox of plankton’. Up to now, there are several mechanisms discussed, which may contribute to local and global diversity of organisms. Several interspecific trade offs have been identified maintaining the coexistence of species like their abilities regarding competition and predator avoidance, their capability to disperse in space and time, and their ability to exploit variable resources. Further, micro-evolutionary dynamics supporting the coexistence of species have been added to our knowledge, and deriving from theoretical deterministic models, non-linear dynamics which describe the temporal fluctuation of abundances of organisms. Whereas competition and predation seem to be clue structural elements within interacting organisms, the intrinsic dynamic behavior – by means of temporal changes in abundance - plays an important role regarding coexistence within a community. The present work sheds light on different factors affecting the coexistence of species using experimental microbial model systems consisting of a bacterivorous ciliate as the predator and two bacteria strains as prey organism. Additionally, another experimental setup consisting of two up to five bacteria species competing for one limiting resource was investigated. Highly controllable chemostat systems were established to exclude extrinsic disturbances. According to theoretical analyses I was able to show - experimentally and theoretically - that phenotypic plasticity of one species within a microbial one-predator-two-prey food web enlarges the range of possible coexistence of all species under different dynamic conditions, compared to a food web without phenotypic plasticity. This was accompanied by non-linear (chaotic) population dynamics within all experimental systems showing phenotypic plasticity. The experiments on the interplay of competition, predation and invasion showed that all aspects have an influence on species coexistence. Under undisturbed controlled conditions all aspects were analyzed in detail and in combination. Populations showed oscillations which were shown by quasi-chaotic attractors in phase space diagrams. Competition experiments with two up to five bacteria species competing for one limiting resource showed that all organisms were able to coexist which was mediated by species oscillations entering a regime of chaos. Besides that fact it was found, that the productivity (biomass) as well as the total cell numbers – under the same nutrition supply – increased by an increasing number of species in the experimental systems. Up to now, the occurrence of non-linear dynamics in well controlled experimental studies has been recognized several times and this phenomenon seemed to be more common in natural systems than generally assumed. N2 - Biodiversität und die Koexistenz von Arten fasziniert und verblüfft Biologen seit Jahr-zehnten und stellen einen Schwerpunkt in der heutigen Umweltforschung dar. Der Schutz und die Konservierung dieser Mannigfaltigkeit stellen eine große Herausfor-derung dar, da die natürlichen Lebensräume sowie die Umwelt enormen Verände-rungen unterworfen sind, welche meist in einem anthropogenen Ursprung wurzeln. Die Koexistenz vieler Arten, auch in relativ homogenen Habitaten ist ein faszinieren-des Charakteristikum natürlicher Lebensgemeinschaften und wird als ‚Paradox des Planktons‘ bezeichnet. Gegenwärtig werden diverse Ursachen diskutiert, welche vermutlich zur lokalen und globalen Diversität von Organismen beitragen. Einige die-ser möglichen Ursachen, die zur Aufrechterhaltung der Koexistenz der Arten beitra-gen, wurden identifiziert: Das Vermögen der Konkurrenz- und Prädationsvermeidung, die Fähigkeit räumlicher sowie zeitlicher Verteilung, sowie das Vermögen variable Ressourcen zu nutzen. Des Weiteren wurden mikro-evolutionäre Phänomene und Dynamiken identifiziert, sowie, von theoretischen deterministischen Modellen ausge-hend, nichtlineare Dynamiken, welche die zeitlichen Schwankungen der Abundanzen von Organismen beschreiben. Diese Aspekte stellen die Schlüsselkomponenten zwi-schen interagierenden Organismen dar, wobei das intrinsiche, nicht lineare dynami-sche Verhalten in Form von zeitlichen Veränderungen in Abundanzen eine zusätzli-che entscheidende Rolle bezüglich der Koexistenz von Arten spielen kann. Einige dieser Aspekte wurden in der vorliegenden Arbeit untersucht. In Anlehnung an theoretische Analysen konnte experimentell sowie theoretisch gezeigt werden, dass phänotypische Plastizität in einer Bakterienart in einem mikrobiellen Ein-Räuber-zwei-Beute-Nahrungsgewebe den Bereich der möglichen Koexistenz unter sich än-dernden experimentellen Bedingungen (Änderungen der Durchflussraten der Chemostate) – im direkten Vergleich zu einem experimentellen Nahrungsgewebe ohne phänotypische Plastizität – erweitern kann. Dies wurde begleitet durch nicht lineare Abundanzschwankungen in den Populationen aller untersuchten Versuchs-ansätze. In weiteren Untersuchungen wurde das Zusammenspiel von Konkurrenz, Prädation und Invasion in einer experimentellen mikrobiellen Gemeinschaft untersucht. Unter kontrollierten Bedingungen konnten diese Aspekte detailliert untersucht werden und es konnten Aufschlüsse darüber gewonnen werden, welche Reaktionen (Interaktionen) innerhalb der untersuchten Gemeinschaften stattfinden. Im Versuchsverlauf wurden Veränderungen in den Abundanzen sowie chaotische Schwankungen der Zellzahlen festgestellt. In Konkurrenzexperimenten von zwei bis zu fünf um eine limitierende Ressource konkurrierende Bakterienarten konnte gezeigt werden, dass alle Arten – vermittelt durch chaotische Abundanzschwankungen – nebeneinander koexistieren konnten. Begleitend dazu wurde herausgefunden, dass die Produktivität (Biomasse) sowie die Gesamtzellzahl bei gleicher Nahrungsverfügbarkeit der experimentellen Systeme mit steigender Artenzahl zunehmen. Gegenwärtig ist das Auftreten von Chaos in gut kontrollierten experimentellen Studien vereinzelt beobachtet worden, wobei dieses Phänomen jedoch häufiger in der Natur aufzutreten scheint als generell vermutet. Y1 - 2012 N1 - Köln, Univ., Diss., 2012 ER - TY - JOUR A1 - Weckesser, Martin A1 - Grießmeier, Martin A1 - Schmidt, Daniela A1 - Sonnenberg, Frank A1 - Ziemons, Karl A1 - Kemna, Lars A1 - Holschbach, Marcus A1 - Langen, Karl-J. A1 - Müller-Gärtner, Hans-W. T1 - Iodine-123 α-methyl tyrosine single-photon emission tomography of cerebral gliomas: standardised evaluation of tumour uptake and extent JF - European Journal of Nuclear Medicine N2 - Single-photon emission tomography (SPET) with the amino acid analogue l-3-[123I]iodo-α-methyl tyrosine (IMT) is helpful in the diagnosis and monitoring of cerebral gliomas. Radiolabelled amino acids seem to reflect tumour infiltration more specifically than conventional methods like magnetic resonance imaging and computed tomography. Automatic tumour delineation based on maximal tumour uptake may cause an overestimation of mean tumour uptake and an underestimation of tumour extension in tumours with circumscribed peaks. The aim of this study was to develop a program for tumour delineation and calculation of mean tumour uptake which takes into account the mean background activity and is thus optimised to the problem of tumour definition in IMT SPET. Using the frequency distribution of pixel intensities of the tomograms a program was developed which automatically detects a reference brain region and draws an isocontour region around the tumour taking into account mean brain radioactivity. Tumour area and tumour/brain ratios were calculated. A three-compartment phantom was simulated to test the program. The program was applied to IMT SPET studies of 20 patients with cerebral gliomas and was compared to the results of manual analysis by three different investigators. Activity ratios and chamber extension of the phantom were correctly calculated by the automatic analysis. A method based on image maxima alone failed to determine chamber extension correctly. Manual region of interest analysis in patient studies resulted in a mean inter-observer standard deviation of 8.7%±6.1% (range 2.7%–25.0%). The mean value of the results of the manual analysis showed a significant correlation to the results of the automatic analysis (r = 0.91, P<0.0001 for the uptake ratio; r = 0.87, P<0.0001 for the tumour area). We conclude that the algorithm proposed simplifies the calculation of uptake ratios and may be used for observer-independent evaluation of IMT SPET studies. Three-dimensional tumour recognition and transfer to co-registered morphological images based on this program may be useful for the planning of surgical and radiation treatment. Y1 - 1998 SN - 1619-7089 VL - 25 IS - 2 SP - 150 EP - 156 ER - TY - JOUR A1 - Taylor, J. G. A1 - Schmitz, N. A1 - Ziemons, Karl A1 - Grosse-Ruyken, M.-L. A1 - Gruber, O. A1 - Müller-Gärtner, H.-W. A1 - Shah, N. J. T1 - The network of brain areas involved in the motion aftereffect JF - Neuroimage N2 - A network of brain areas is expected to be involved in supporting the motion aftereffect. The most active components of this network were determined by means of an fMRI study of nine subjects exposed to a visual stimulus of moving bars producing the effect. Across the subjects, common areas were identified during various stages of the effect, as well as networks of areas specific to a single stage. In addition to the well-known motion-sensitive area MT the prefrontal brain areas BA44 and 47 and the cingulate gyrus, as well as posterior sites such as BA37 and BA40, were important components during the period of the motion aftereffect experience. They appear to be involved in control circuitry for selecting which of a number of processing styles is appropriate. The experimental fMRI results of the activation levels and their time courses for the various areas are explored. Correlation analysis shows that there are effectively two separate and weakly coupled networks involved in the total process. Implications of the results for awareness of the effect itself are briefly considered in the final discussion. Y1 - 2000 SN - 1053-8119 VL - 11 IS - 4 SP - 257 EP - 270 ER - TY - JOUR A1 - Fink, G. R. A1 - Marshall, J. C. A1 - Shah, N. J. A1 - Weiss, P.H. A1 - Halligan, P. W. A1 - Grosse-Ruyken, M. A1 - Ziemons, Karl A1 - Zilles, K. A1 - Freund, H. J. T1 - Line bisection judgments implicate right parietal cortex and cerebellum as assessed by fMRI JF - Neurology Y1 - 2000 SN - 1526-632X VL - 54 IS - 6 SP - 1324 EP - 1331 ER - TY - JOUR A1 - Streun, M. A1 - Brandenburg, G. A1 - Larue, H. A1 - Zimmermann, E. A1 - Ziemons, Karl A1 - Halling, H. T1 - Pulse recording by free-running sampling JF - 2000 IEEE Nuclear Science Symposium Conference Record, Vol. 2 N2 - Pulses from a position-sensitive photomultiplier (PS-PMT) are recorded by free running ADCs at a sampling rate of 40 MHz. A four-channel acquisition-board has been developed which is equipped with four 12 bit-ADCs connected to one FPGA (field programmable gate array). The FPGA manages data acquisition and the transfer to the host computer. It can also work as a digital trigger, so a separate hardware-trigger can be omitted. The method of free running sampling provides a maximum of information, besides the pulse charge and amplitude also pulse shape and starting time are contained in the sampled data. These informations are crucial for many tasks such as distinguishing between different scintillator materials, determination of radiation type, pile-up recovery, coincidence detection or time-of-flight applications. The absence of an analog integrator allows coping with very high count rates. Since this method is going to be employed in positron emission tomography (PET), the position of an event is another important information. The simultaneous readout of four channels allows localization by means of center-of-gravity weighting. First results from a test setup with LSO-scintillators coupled to the PS-PMT are presented Y1 - 2000 SN - 1082-3654 SP - 9/179 EP - 9/181 ER - TY - JOUR A1 - Streun, M. A1 - Brandenburg, G. A1 - Larue, H. A1 - Zimmermann, E. A1 - Ziemons, Karl A1 - Halling, H. T1 - Pulse recording by free-running sampling JF - IEEE Transactions on Nuclear Science N2 - Pulses from a position-sensitive photomultiplier (PS-PMT) are recorded by free-running ADCs at a sampling rate of 40 MHz. A four-channel acquisition board has been developed which is equipped with four 12-bit ADCs connected to one field programmable gate array (FPGA). The FPGA manages data acquisition and the transfer to the host computer. It can also work as a digital trigger, so a separate hardware trigger can be omitted. The method of free-running sampling provides a maximum of information, besides the pulse charge and amplitude also pulse shape and starting time are contained in the sampled data. This information is crucial for many tasks such as distinguishing between different scintillator materials, determination of radiation type, pile-up recovery, coincidence detection or time-of-flight applications. The absence of an analog integrator allows very high count rates to be dealt with. Since this method is to be employed in positron emission tomography (PET), the position of an event is also important. The simultaneous readout of four channels allows localization by means of center-of-gravity weighting. First results from a test setup with LSO scintillators coupled to the PS-PMT are presented here Y1 - 2001 SN - 0018-9499 VL - 48 IS - 3 SP - 524 EP - 526 ER - TY - JOUR A1 - Heinrich, U. A1 - Blum, A. A1 - Bussmann, N. A1 - Engels, R. A1 - Kemmerling, G. A1 - Weber, S. A1 - Ziemons, Karl T1 - Statistical studies on the light output and energy resolution of small LSO single crystals with different surface treatments combined with various reflector materials JF - Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment N2 - The optimization of light output and energy resolution of scintillators is of special interest for the development of high resolution and high sensitivity PET. The aim of this work is to obtain statistically reliable results concerning optimal surface treatment of scintillation crystals and the selection of reflector material. For this purpose, raw, mechanically polished and etched LSO crystals (size 2×2×10 mm3) were combined with various reflector materials (Teflon tape, Teflon matrix, BaSO4) and exposed to a 22Na source. In order to ensure the statistical reliability of the results, groups of 10 LSO crystals each were measured for all combinations of surface treatment and reflector material. Using no reflector material the light output increased up to 551±35% by mechanical polishing the surface compared to 100±5% for raw crystals. Etching the surface increased the light output to 441±29%. The untreated crystals had an energy resolution of 24.6±4.0%. By mechanical polishing the surface it was possible to achieve an energy resolution of 13.2±0.8%, by etching of 14.8±0.7%. In combination with BaSO4 as reflector material the maximum increase of light output has been established to 932±57% for mechanically polished and 895±61% for etched crystals. The combination with BaSO4 also caused the best improvement of the energy resolution up to 11.6±0.2% for mechanically polished and 12.2±0.3% for etched crystals. Relating to the light output there was no significant statistical difference between the two surface treatments in combination with BaSO4. In contrast to this, the statistical results of the energy resolution have shown the combination of mechanical polishing and BaSO4 as the optimum. Y1 - 2002 SN - 0168-9002 N1 - Proceedings of the 6th International Conference on Inorganic Scin tillators and their Use in Scientific and Industrial Applications VL - 486 IS - 1-2 SP - 60 EP - 66 ER - TY - JOUR A1 - Streun, M. A1 - Brandenburg, G. A1 - Larue, H. A1 - Zimmermann, E. A1 - Ziemons, Karl A1 - Halling, H. T1 - A PET system with free running ADCs JF - Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment N2 - A small PET system has been built up with two multichannel photomultipliers, which are attached to a matrix of 64 single LSO crystals each. The signal from each multiplier is being sampled continuously by a 12 bit ADC at a sampling frequency of 40 MHz. In case of a scintillation pulse a subsequent FPGA sends the corresponding set of samples together with the channel information and a time mark to the host computer. The data transfer is performed with a rate of 20 MB/s. On the host all necessary information is extracted from the data. The pulse energy is determined, coincident events are detected and multiple hits within one matrix can be identified. In order to achieve a narrow time window the pulse starting time is refined further than the resolution of the time mark (=25 ns) would allow. This is possible by interpolating between the pulse samples. First data obtained from this system will be presented. The system is part of developments for a much larger system and has been created to study the feasibility and performance of the technique and the hardware architecture. Y1 - 2002 SN - 0168-9002 N1 - Proceedings of the 6th International Conference on Inorganic Scin tillators and their Use in Scientific and Industrial Applications VL - 486 IS - 1-2 SP - 18 EP - 21 ER - TY - JOUR A1 - Streun, M. A1 - Brandenburg, G. A1 - Larue, H. A1 - Zimmermann, E. A1 - Ziemons, Karl A1 - Halling, H. T1 - Coincidence detection by digital processing of free-running sampled pulses JF - Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment N2 - Coincident events in two scintillator crystals coupled to photomultipliers (PMT) are detected by processing just the digital data of the recorded pulses. For this purpose the signals from both PMTs are continuously sampled by free-running ADCs at a sampling rate of 40 MHz. For each sampled pulse the starting time is determined by processing the pulse data. Even a fairly simple interpolating algorithm results in a FWHM of about 2 ns. Y1 - 2002 SN - 0168-9002 VL - 487 IS - 3 SP - 530 EP - 534 ER - TY - JOUR A1 - Khodaverdi, M. A1 - Chatziioannou, A. F. A1 - Weber, S. A1 - Ziemons, Karl A1 - Halling, H. A1 - Pietrzyk, U. T1 - Investigation of different MicroCT scanner configurations by GEANT4 simulations JF - IEEE Transactions on Nuclear Science N2 - This study has been performed to design the combination of the new ClearPET (ClearPET is a trademark of the Crystal Clear Collaboration), a small animal positron emission tomography (PET) system, with a micro-computed tomography (microCT) scanner. The properties of different microCT systems have been determined by simulations based on GEANT4. We will demonstrate the influence of the detector material and the X-ray spectrum on the obtained contrast. Four different detector materials (selenium, cadmium zinc telluride, cesium iodide and gadolinium oxysulfide) and two X-ray spectra (a molybdenum and a tungsten source) have been considered. The spectra have also been modified by aluminum filters of varying thickness. The contrast between different tissue types (water, air, brain, bone and fat) has been simulated by using a suitable phantom. The results indicate the possibility to improve the image contrast in microCT by an optimized combination of the X-ray source and detector material. Y1 - 2005 SN - 0018-9499 VL - 52 IS - 1 SP - 188 EP - 192 ER - TY - JOUR A1 - Streun, M. A1 - Brandenburg, G. A1 - Larue, H. A1 - Parl, C. A1 - Ziemons, Karl T1 - The data acquisition system of ClearPET neuro - a small animal PET scanner JF - IEEE Transactions on Nuclear Science N2 - The Crystal Clear Collaboration has developed a modular system for a small animal PET scanner (ClearPET). The modularity allows the assembly of scanners of different sizes and characteristics in order to satisfy the specific needs of the individual member institutions. The system performs depth of interaction detection by using a phoswich arrangement combining LSO and LuYAP scintillators which are coupled to Multichannel Photomultipliers (PMTs). For each PMT a free running 40 MHz ADC digitizes the signal and the complete scintillation pulse is sampled by an FPGA and sent with 20 MB/s to a PC for preprocessing. The pulse provides information about the gamma energy and the scintillator material which identifies the interaction layer. Furthermore, the exact pulse starting time is obtained from the sampled data. This is important as no hardware coincidence detection is implemented. All single events are recorded and coincidences are identified by software. The system in Jülich (ClearPET Neuro) is equipped with 10240 crystals on 80 PMTs. The paper will present an overview of the data acquisition system. Y1 - 2006 SN - 0018-9499 VL - 53 IS - 3 SP - 700 EP - 703 ER - TY - JOUR A1 - Khodaverdi, M. A1 - Weber, S. A1 - Streun, M. A1 - Parl, C. A1 - Ziemons, Karl T1 - High resolution imaging with ClearPET™ Neuro - first animal images JF - 2005 IEEE Nuclear Science Symposium Conference Record, Vol. 3 N2 - The ClearPET™ Neuro is the first full ring scanner within the Crystal Clear Collaboration (CCC). It consists of 80 detector modules allocated to 20 cassettes. LSO and LuYAP:Ce crystals in phoswich configuration in combination with position sensitive photomultiplier tubes are used to achieve high sensitivity and realize the acquisition of the depth of interaction (DOI) information. The complete system has been tested concerning the mechanical and electronical stability and interplay. Moreover, suitable corrections have been implemented into the reconstruction procedure to ensure high image quality. We present first results which show the successful operation of the ClearPET™ Neuro for artefact free and high resolution small animal imaging. Based on these results during the past few months the ClearPET™ Neuro System has been modified in order to optimize the performance. Y1 - 2006 SN - 1082-3654 SP - 1641 EP - 1644 ER - TY - JOUR A1 - Streun, M. A1 - Brandenburg, G. A1 - Khodaverdi, M. A1 - Larue, H. A1 - Parl, C. A1 - Ziemons, Karl T1 - Timemark correction for the ClearPET™ scanners JF - 2005 IEEE Nuclear Science Symposium Conference Record, Vol. 4 N2 - The small animal PET scanners developed by the Crystal Clear Collaboration (ClearPETtrade) detect coincidences by analyzing timemarks which are attached to each event. The scanners are able to save complete single list mode data which allows analysis and modification of the timemarks after data acquisition. The timemarks are obtained from the digitally sampled detector pulses by calculating the baseline crossing of the rising edge of the pulse which is approximated as a straight line. But the limited sampling frequency causes a systematic error in the determination of the timemark. This error depends on the phase of the sampling clock at the time of the event. A statistical method that corrects these errors will be presented Y1 - 2006 SN - 1082-3654 SP - 2057 EP - 2060 ER - TY - JOUR A1 - Mosset, J.-B. A1 - Devroede, O. A1 - Krieguer, M. A1 - Rey, M. A1 - Vieira, J.-M. A1 - Jung, J. H. A1 - Kuntner, C. A1 - Streun, M. A1 - Ziemons, Karl A1 - Auffray, E. A1 - Sempere-Roldan, P. A1 - Lecoq, P. A1 - Bruyndonckx, P. A1 - Loude, J.-F. A1 - Tavernier, S. A1 - Morcel, C. T1 - Development of an optimized LSO/LuYAP phoswich detector head for the Lausanne ClearPET demonstrator JF - IEEE Transactions on Nuclear Science N2 - This paper describes the LSO/LuYAP phoswich detector head developed for the ClearPET small animal PET scanner demonstrator that is under construction in Lausanne within the Crystal Clear Collaboration. The detector head consists of a dual layer of 8×8 LSO and LuYAP crystal arrays coupled to a multi-anode photomultiplier tube (Hamamatsu R7600-M64). Equalistion of the LSO/LuYAP light collection is obtained through partial attenuation of the LSO scintillation light using a thin aluminum deposit of 20-35 nm on LSO and appropriate temperature regulation of the phoswich head between 30°C to 60°C. At 511keV, typical FWHM energy resolutions of the pixels of a phoswich head amounts to (28±2)% for LSO and (25±2)% for LuYAP. The LSO versus LuYAP crystal identification efficiency is better than 98%. Six detector modules have been mounted on a rotating gantry. Axial and tangential spatial resolutions were measured up to 4 cm from the scanner axis and compared to Monte Carlo simulations using GATE. FWHM spatial resolution ranges from 1.3 mm on axis to 2.6 mm at 4 cm from the axis. Y1 - 2006 SN - 0018-9499 VL - 53 IS - 1 SP - 25 EP - 29 ER - TY - JOUR A1 - Streun, M. A1 - Beer, S. A1 - Hombach, T. A1 - Jahnke, S. A1 - Khodaverdi, M. A1 - Larue, H. A1 - Minwuyelet, S. A1 - Parl, C. A1 - Roeb, G. A1 - Schurr, U. A1 - Ziemons, Karl T1 - PlanTIS: A positron emission tomograph for imaging 11C transport in plants JF - 2007 IEEE Nuclear Science Symposium Conference Record, Vol. 6 N2 - Plant growth and transport processes are highly dynamic. They are characterized by plant-internal control processes and by strong interactions with the spatially and temporally varying environment. Analysis of structure- function relations of growth and transport in plants will strongly benefit from the development of non-invasive techniques. PlanTIS (Plant Tomographic Imaging System) is designed for non-destructive 3D-imaging of positron emitting radiotracers. It will permit functional analysis of the dynamics of carbon distribution in plants including bulky organs. It will be applicable for screening transport properties of plants to evaluate e.g. temperature adaptation of genetically modified plants. PlanTIS is a PET scanner dedicated to monitor the dynamics of the 11C distribution within a plant while or after assimilation of 11CO2. Front end electronics and data acquisition architecture of the scanner are based on the ClearPETTM system [1]. Four detector modules form one of two opposing detector blocks. Optionally, a hardware coincidence detection between the blocks can be applied. In general the scan duration is rather long (~ 1 hour) compared to the decay time of 11C (20 min). As a result the count rates can vary over a wide range and accurate dead time correction is necessary. Y1 - 2008 SN - 1082-3654 SP - 4110 EP - 4112 ER - TY - JOUR A1 - Ziemons, Karl A1 - Bruyndonckx, P. A1 - Perez, J. M. A1 - Pietrzyk, U. A1 - Rato, P. A1 - Tavernier, S. T1 - Beyond ClearPET: Next Aims JF - 5th IEEE International Symposium on Biomedical Imaging: From Nano to Macro Symposium Proceedings ISBI 2008 N2 - The CRYSTAL CLEAR collaboration, in short CCC, is a consortium of 12 academic institutions, mainly from Europe, joining efforts in the area of developing instrumentation for nuclear medicine and medical imaging. In the framework of the CCC a high performance small animal PET system, called ClearPET, was developed by using new technologies in electronics and crystals in a phoswich arrangement combining two types of lutetium- based scintillator materials: LSO:Ce and LuYAP:Ce. Our next aim will be the development of hybrid image systems. Hybrid MR-PET imaging has many unique advantages for brain research. This has sparked a new research line within CCC for the development of novel MR-PET compatible technologies. MRI is not as sensitive as PET but PET has poorer spatial resolution than MRI. Two major advantages of PET are sensitivity and its ability to acquire metabolic information. To assess these innovations, the development of a 9.4T hybrid animal MR-PET scanner is proposed based on an existing 9.4T MR scanner that will be adapted to enable simultaneous acquisition of MR and PET data using cutting- edge technology for both MR and PET. Y1 - 2008 SN - 978-1-4244-2003-2 SP - 1421 EP - 1424 ER - TY - JOUR A1 - Jahnke, Siegfried A1 - Menzel, Marion I. A1 - Dusschoten, Dagmar van A1 - Roeb, Gerhard W. A1 - Bühler, Jonas A1 - Minwuyelet, Senay A1 - Blümler, Peter A1 - Temperton, Vicky M. A1 - Hombach, Thomas A1 - Streun, Matthias A1 - Beer, Simone A1 - Khodaverdi, Maryam A1 - Ziemons, Karl A1 - Coenen, Heinz H. A1 - Schurr, Ulrich T1 - Combined MRI–PET dissects dynamic changes in plant structures and functions JF - The Plant Journal N2 - Unravelling the factors determining the allocation of carbon to various plant organs is one of the great challenges of modern plant biology. Studying allocation under close to natural conditions requires non-invasive methods, which are now becoming available for measuring plants on a par with those developed for humans. By combining magnetic resonance imaging (MRI) and positron emission tomography (PET), we investigated three contrasting root/shoot systems growing in sand or soil, with respect to their structures, transport routes and the translocation dynamics of recently fixed photoassimilates labelled with the short-lived radioactive carbon isotope 11C. Storage organs of sugar beet (Beta vulgaris) and radish plants (Raphanus sativus) were assessed using MRI, providing images of the internal structures of the organs with high spatial resolution, and while species-specific transport sectoralities, properties of assimilate allocation and unloading characteristics were measured using PET. Growth and carbon allocation within complex root systems were monitored in maize plants (Zea mays), and the results may be used to identify factors affecting root growth in natural substrates or in competition with roots of other plants. MRI–PET co-registration opens the door for non-invasive analysis of plant structures and transport processes that may change in response to genomic, developmental or environmental challenges. It is our aim to make the methods applicable for quantitative analyses of plant traits in phenotyping as well as in understanding the dynamics of key processes that are essential to plant performance. Y1 - 2009 SN - 1365-313X VL - 59 IS - 4 SP - 634 EP - 644 PB - Wiley CY - Weinheim ER -