TY - JOUR A1 - Al-Kaidy, Huschyar A1 - Duwe, Anna A1 - Huster, Manuel A1 - Muffler, Kai A1 - Schlegel, Christin A1 - Tim, Sieker A1 - Stadtmüller, Ralf A1 - Tippkötter, Nils A1 - Ulber, Roland T1 - Biotechnology and bioprocess engineering – from the first ullmann's article to recent trends JF - ChemBioEng Reviews N2 - For several thousand years, biotechnology and its associated technical processes have had a great impact on the development of mankind. Based on empirical methods, in particular for the production of foodstuffs and daily commodities, these disciplines have become one of the most innovative future issues. Due to the increasing detailed understanding of cellular processes, production strains can now be optimized. In combination with modern bioprocesses, a variety of bulk and fine chemicals as well as pharmaceuticals can be produced efficiently. In this article, some of the current trends in biotechnology are discussed. Y1 - 2015 U6 - http://dx.doi.org/10.1002/cben.201500008 VL - 2 IS - 3 SP - 175 EP - 184 PB - Wiley CY - Weinheim ER - TY - JOUR A1 - Al-Kaidy, Huschyar A1 - Kuthan, Kai A1 - Hering, Thomas A1 - Tippkötter, Nils T1 - Aqueous droplets used as enzymatic microreactors and their electromagnetic actuation JF - Journal of Visualized Experiments N2 - For the successful implementation of microfluidic reaction systems, such as PCR and electrophoresis, the movement of small liquid volumes is essential. In conventional lab-on-a-chip-platforms, solvents and samples are passed through defined microfluidic channels with complex flow control installations. The droplet actuation platform presented here is a promising alternative. With it, it is possible to move a liquid drop (microreactor) on a planar surface of a reaction platform (lab-in-a-drop). The actuation of microreactors on the hydrophobic surface of the platform is based on the use of magnetic forces acting on the outer shell of the liquid drops which is made of a thin layer of superhydrophobic magnetite particles. The hydrophobic surface of the platform is needed to avoid any contact between the liquid core and the surface to allow a smooth movement of the microreactor. On the platform, one or more microreactors with volumes of 10 µL can be positioned and moved simultaneously. The platform itself consists of a 3 x 3 matrix of electrical double coils which accommodate either neodymium or iron cores. The magnetic field gradients are automatically controlled. By variation of the magnetic field gradients, the microreactors' magnetic hydrophobic shell can be manipulated automatically to move the microreactor or open the shell reversibly. Reactions of substrates and corresponding enzymes can be initiated by merging the microreactors or bringing them into contact with surface immobilized catalysts. Y1 - 2016 U6 - http://dx.doi.org/10.3791/54643 SN - 1940-087X IS - Issue 126 ER - TY - JOUR A1 - Al-Kaidy, Huschyar A1 - Tippkötter, Nils T1 - Superparamagnetic hydrophobic particles as shell material for digital microfluidic droplets and proof-of-principle reaction assessments with immobilized laccase JF - Engineering in Life Sciences N2 - In the field of biotechnology and molecular biology, the use of small liquid volumes has significant advantages. In particular, screening and optimization runs with acceptable amounts of expensive and hardly available catalysts, reagents, or biomolecules are feasible with microfluidic technologies. The presented new microfluidic system is based on the inclusion of small liquid volumes by a protective shell of magnetizable microparticles. Hereby, discrete aqueous microreactor drops with volumes of 1–30 μL can be formed on a simple planar surface. A digital movement and manipulation of the microreactor is performed by overlapping magnetic forces. The magnetic forces are generated by an electrical coil matrix positioned below a glass plate. With the new platform technology, several discrete reaction compartments can be moved simultaneously on one surface. Due to the magnetic fields, the reactors can even be merged to initiate reactions by mixing or positioned above surface-immobilized catalysts and then opened by magnetic force. Comparative synthesis routes of the magnetizable shell particles and superhydrophobic glass slides including their performance and stability with the reaction platform are described. The influence of diffusive mass transport during the catalyzed reaction is discussed by evaluation finite element model of the microreactor. Furthermore, a first model dye reaction of the enzyme laccase has been established. Y1 - 2016 U6 - http://dx.doi.org/10.1002/elsc.201400124 VL - 16 IS - 3 SP - 222 EP - 230 PB - Wiley-VCH CY - Weinheim ER - TY - PAT A1 - Al-Kaidy, Huschyar A1 - Tippkötter, Nils A1 - Ulber, Roland T1 - A system and a method for the implementation of chemical, biological or physical reactions [Europäische Patentanmeldung] N2 - The invention relates to a system for the implementation of chemical, biological or physical reactions, consisting of - one or more magnetic micro-reactors, each comprising a shell made of hydrophobic magnetic nanoparticles encapsulating an aqueous core, - a plane platform comprising a surface to receive the micro-reactors, - a source that generates a magnetic field above or underneath the platform for manipulating the one or more hydrophobic magnetic micro-reactors, or for moving them along the surface of the platform from one position to another position, characterized in that the aqueous core of the one or more magnetic micro-reactors contains a reaction solution or buffer, and wherein the magnetic field generated by the source correlates to a defined position on the surface of the platform. Y1 - 2013 PB - Europäisches Patentamt CY - Den Hague ER - TY - JOUR A1 - Albanna, W. A1 - Conzen, C. A1 - Weiss, M. A1 - Clusmann, H. A1 - Fuest, M. A1 - Mueller, M. A1 - Brockmann, M.A. A1 - Vilser, W. A1 - Schmidt-Trucksäss, A. A1 - Hoellig, A. A1 - Seiz, M. A1 - Thomé, C. A1 - Kotliar, Konstantin A1 - Schubert, G.A. T1 - Retinal Vessel Analysis (RVA) in the context of subarachnoid hemorrhage: A proof of concept study JF - PLoS ONE N2 - Background Timely detection of impending delayed cerebral ischemia after subarachnoid hemorrhage (SAH) is essential to improve outcome, but poses a diagnostic challenge. Retinal vessels as an embryological part of the intracranial vasculature are easily accessible for analysis and may hold the key to a new and non-invasive monitoring technique. This investigation aims to determine the feasibility of standardized retinal vessel analysis (RVA) in the context of SAH. Methods In a prospective pilot study, we performed RVA in six patients awake and cooperative with SAH in the acute phase (day 2–14) and eight patients at the time of follow-up (mean 4.6±1.7months after SAH), and included 33 age-matched healthy controls. Data was acquired using a manoeuvrable Dynamic Vessel Analyzer (Imedos Systems UG, Jena) for examination of retinal vessel dimension and neurovascular coupling. Results Image quality was satisfactory in the majority of cases (93.3%). In the acute phase after SAH, retinal arteries were significantly dilated when compared to the control group (124.2±4.3MU vs 110.9±11.4MU, p<0.01), a difference that persisted to a lesser extent in the later stage of the disease (122.7±17.2MU, p<0.05). Testing for neurovascular coupling showed a trend towards impaired primary vasodilation and secondary vasoconstriction (p = 0.08, p = 0.09 resp.) initially and partial recovery at the time of follow-up, indicating a relative improvement in a time-dependent fashion. Conclusion RVA is technically feasible in patients with SAH and can detect fluctuations in vessel diameter and autoregulation even in less severely affected patients. Preliminary data suggests potential for RVA as a new and non-invasive tool for advanced SAH monitoring, but clinical relevance and prognostic value will have to be determined in a larger cohort. Y1 - 2016 U6 - http://dx.doi.org/10.1371/journal.pone.0158781 SN - 1932-6203 VL - 11 IS - 7 PB - PLOS CY - San Francisco ER - TY - JOUR A1 - Albanna, Walid A1 - Conzen, Catharina A1 - Weiss, Miriam A1 - Seyfried, Katharina A1 - Kotliar, Konstantin A1 - Schmidt, Tobias Philip A1 - Kuerten, David A1 - Hescheler, Jürgen A1 - Bruecken, Anne A1 - Schmidt-Trucksäss, Arno A1 - Neumaier, Felix A1 - Wiesmann, Martin A1 - Clusmann, Hans A1 - Schubert, Gerrit Alexander T1 - Non-invasive assessment of neurovascular coupling after aneurysmal subarachnoid hemorrhage: a prospective observational trial using retinal vessel analysis JF - Frontiers in Neurology N2 - Delayed cerebral ischemia (DCI) is a common complication after aneurysmal subarachnoid hemorrhage (aSAH) and can lead to infarction and poor clinical outcome. The underlying mechanisms are still incompletely understood, but animal models indicate that vasoactive metabolites and inflammatory cytokines produced within the subarachnoid space may progressively impair and partially invert neurovascular coupling (NVC) in the brain. Because cerebral and retinal microvasculature are governed by comparable regulatory mechanisms and may be connected by perivascular pathways, retinal vascular changes are increasingly recognized as a potential surrogate for altered NVC in the brain. Here, we used non-invasive retinal vessel analysis (RVA) to assess microvascular function in aSAH patients at different times after the ictus. Y1 - 2021 U6 - http://dx.doi.org/10.3389/fneur.2021.690183 SN - 1664-2295 VL - 12 IS - 12 SP - 1 EP - 15 ER - TY - JOUR A1 - Albanna, Walid A1 - Kotliar, Konstantin A1 - Lüke, Jan Niklas A1 - Alpdogan, Serdar A1 - Conzen, Catharina A1 - Lindauer, Ute A1 - Clusmann, Hans A1 - Hescheler, Jürgen A1 - Vilser, Walthard A1 - Schneider, Toni A1 - Schubert, Gerrit Alexander T1 - Non-invasive evaluation of neurovascular coupling in the murine retina by dynamic retinal vessel analysis JF - Plos one N2 - Background Impairment of neurovascular coupling (NVC) was recently reported in the context of subarachnoid hemorrhage and may correlate with disease severity and outcome. However, previous techniques to evaluate NVC required invasive procedures. Retinal vessels may represent an alternative option for non-invasive assessment of NVC. Methods A prototype of an adapted retinal vessel analyzer was used to assess retinal vessel diameter in mice. Dynamic vessel analysis (DVA) included an application of monochromatic flicker light impulses in predefined frequencies for evaluating NVC. All retinae were harvested after DVA and electroretinograms were performed. Results A total of 104 retinal scans were conducted in 21 male mice (90 scans). Quantitative arterial recordings were feasible only in a minority of animals, showing an emphasized reaction to flicker light impulses (8 mice; 14 scans). A characteristic venous response to flicker light, however, could observed in the majority of animals. Repeated measurements resulted in a significant decrease of baseline venous diameter (7 mice; 7 scans, p < 0.05). Ex-vivo electroretinograms, performed after in-vivo DVA, demonstrated a significant reduction of transretinal signaling in animals with repeated DVA (n = 6, p < 0.001). Conclusions To the best of our knowledge, this is the first non-invasive study assessing murine retinal vessel response to flicker light with characteristic changes in NVC. The imaging system can be used for basic research and enables the investigation of retinal vessel dimension and function in control mice and genetically modified animals. Y1 - 2018 U6 - http://dx.doi.org/10.1371/journal.pone.0204689 VL - 13 IS - 10 PB - PLOS CY - San Francisco ER - TY - JOUR A1 - Albanna, Walid A1 - Lueke, Jan Niklas A1 - Sjapic, Volha A1 - Kotliar, Konstantin A1 - Hescheler, Jürgen A1 - Clusmann, Hans A1 - Sjapic, Sergej A1 - Alpdogan, Serdan A1 - Schneider, Toni A1 - Schubert, Gerrit Alexander A1 - Neumaier, Felix T1 - Electroretinographic Assessment of Inner Retinal Signaling in the Isolated and Superfused Murine Retina JF - Current Eye Research Y1 - 2017 U6 - http://dx.doi.org/10.1080/02713683.2017.1339807 SN - 1460-2202 IS - Article in press SP - 1 EP - 9 PB - Taylor & Francis CY - London ER - TY - JOUR A1 - Albanna, Walid A1 - Lüke, Jan Niklas A1 - Schubert, Gerrit Alexander A1 - Dibué-Adjei, Maxine A1 - Kotliar, Konstantin A1 - Hescheler, Jürgen A1 - Clusmann, Hans A1 - Steiger, Hans-Jakob A1 - Hänggi, Daniel A1 - Kamp, Marcel A. A1 - Schneider, Toni A1 - Neumaier, Felix T1 - Modulation of Ca v 2.3 channels by unconjugated bilirubin (UCB) – Candidate mechanism for UCB-induced neuromodulation and neurotoxicity JF - Molecular and Cellular Neuroscience Y1 - 2019 U6 - http://dx.doi.org/10.1016/j.mcn.2019.03.003 SN - 1044-7431 VL - 96 IS - 4 SP - 35 EP - 46 PB - Elsevier CY - Amsterdam ER - TY - THES A1 - Albracht, Kirsten T1 - Influence of mechanical properties of the leg extensor muscletendon units on running economy Y1 - 2010 N1 - Cologne, German Sport Univ., Diss., 2010 PB - Deutsche Sporthochschule Köln CY - Köln ER - TY - JOUR A1 - Albracht, Kirsten A1 - Arampatzis, A. A1 - Baltzopoulos, V. T1 - Assessment of muscle volume and physiological cross-sectional area of the human triceps surae muscle in vivo JF - Journal of Biomechanics Y1 - 2008 U6 - http://dx.doi.org/10.1016/j.jbiomech.2008.04.020 SN - 0021-9290 VL - 41 SP - 2211 EP - 2218 ER - TY - JOUR A1 - Albracht, Kirsten A1 - Arampatzis, Adamantios T1 - Exercise-induced changes in triceps surae tendon stiffness and muscle strength affect running economy in humans JF - European Journal of Applied Physiology Y1 - 2013 U6 - http://dx.doi.org/10.1007/s00421-012-2585-4 SN - 1439-6327 VL - 113 IS - 6 SP - 1605 EP - 1615 PB - Springer CY - Berlin ER - TY - JOUR A1 - Albracht, Kirsten A1 - Arampatzis, Adamantios T1 - Influence of the mechanical properties of the muscle-tendon unit on force generation in runners with different running economy JF - Biological Cybernetics Y1 - 2006 U6 - http://dx.doi.org/10.1007/s00422-006-0070-z SN - 1432-0770 VL - 95 IS - 1 SP - 87 EP - 96 ER - TY - JOUR A1 - Alebouyeh Samami, Behzad A1 - Pieper, Martin A1 - Breitbach, Gerd A1 - Hodapp, Josef T1 - Heat production in the windings of the stators of electric machines under stationary condition JF - Heat and mass transfer N2 - In electric machines due to high currents and resistive losses (joule heating) heat is produced. To avoid damages by overheating the design of effective cooling systems is required. Therefore the knowledge of heat sources and heat transfer processes is necessary. The purpose of this paper is to illustrate a good and effective calculation method for the temperature analysis based on homogenization techniques. These methods have been applied for the stator windings in a slot of an electric machine consisting of copper wires and resin. The key quantity here is an effective thermal conductivity, which characterizes the heterogeneous wire resin-arrangement inside the stator slot. To illustrate the applicability of the method, the analysis of a simplified, homogenized model is compared with the detailed analysis of temperature behavior inside a slot of an electric machine according to the heat generation. We considered here only the stationary situation. The achieved numerical results are accurate and show that the applied homogenization technique works in practice. Finally the results of simulations for the two cases, the original model of the slot and the homogenized model chosen for the slot (unit cell), are compared to experimental results. Y1 - 2014 U6 - http://dx.doi.org/10.1007/s00231-014-1371-8 SN - 0947-7411 (Print) ; 1432-1181 (E-Journal) VL - 50 SP - 1707 EP - 1716 PB - Springer CY - Heidelberg ER - TY - JOUR A1 - Aletsee, Ludwig A1 - Baumann, Marcus T1 - A laboratory incubator equipped with facilities to automatically simulate natural irradiance JF - Boletim do Instituto Oceanográfico / Universidade de São Paulo Y1 - 1991 SN - 1982-436X; 0080-6331 VL - Vol. 39 IS - No. 2 SP - 155 EP - 159 ER - TY - JOUR A1 - Alexopoulos, Spiros T1 - Biogas systems: basics, biogas multifunction, principle of fermentation and hybrid application with a solar tower for the treatment of waste animal manure JF - Journal of Engineering Science and Technology Review N2 - Two of the main environmental problems of today’s society are the continuously increasing production of organic wastes as well as the increase of carbon dioxide in the atmosphere and the related green house effect. A way to solve these problems is the production of biogas. Biogas is a combustible gas consisting of methane, carbon dioxide and small amounts of other gases and trace elements. Production of biogas through anaerobic digestion of animal manure and slurries as well as of a wide range of digestible organic wastes and agricultural residues, converts these substrates into electricity and heat and offers a natural fertiliser for agriculture. The microbiological process of decomposition of organic matter, in the absence of oxygen takes place in reactors, called digesters. Biogas can be used as a fuel in a gas turbine or burner and can be used in a hybrid solar tower system offering a solution for waste treatment of agricultural and animal residues. A solar tower system consists of a heliostat field, which concentrates direct solar irradiation on an open volumetric central receiver. The receiver heats up ambient air to temperatures of around 700°C. The hot air’s heat energy is transferred to a steam Rankine cycle in a heat recovery steam generator (HRSG). The steam drives a steam turbine, which in turn drives a generator for producing electricity. In order to increase the operational hours of a solar tower power plant, a heat storage system and/ or hybridization may be considered. The advantage of solar-fossil hybrid power plants, compared to solar-only systems, lies in low additional investment costs due to an adaptable solar share and reduced technical and economical risks. On sunny days the hybrid system operates in a solar-only mode with the central receiver and on cloudy days and at night with the gas turbine only. As an alternative to methane gas, environmentally neutral biogas can be used for operating the gas turbine. Hence, the hybrid system is operated to 100% from renewable energy sources Y1 - 2012 SN - 1791-2377 N1 - Special Issue on Renewable Energy Systems VL - 5 IS - 4 SP - 48 EP - 55 ER - TY - CHAP A1 - Alexopoulos, Spiros T1 - Biomass technology and bio-fuels: Heating/cooling and power T2 - Renewable energy systems : theory, innovations, and intelligent applications / eds.: Socrates Kaplanis and Eleni Kaplani Y1 - 2013 SN - 9781624177415 SP - 501 EP - 523 PB - Nova Science Publ. CY - Hauppauge, NY ER - TY - JOUR A1 - Alexopoulos, Spiros T1 - Simulation model for the transient process behaviour of solar aluminium recycling in a rotary kiln JF - Applied Thermal Engineering Y1 - 2015 U6 - http://dx.doi.org/10.1016/j.applthermaleng.2015.01.007 SN - 1359-4311 N1 - Autor im Original: Spiridon O. Alexopoulos VL - 78 SP - 387 EP - 396 PB - Elsevier CY - Amsterdam ER - TY - CHAP A1 - Alexopoulos, Spiros A1 - Breitbach, Gerd A1 - Hoffschmidt, Bernhard T1 - Optimization of the channel form geometry of porous ReSiC ceramic membrane modules T2 - Proceedings / International Conference & Exhibition for Filtration and Separation Technology, FILTECH 2009 : October 13 - 15, 2009, Wiesbaden, Germany. Vol. 2 Y1 - 2009 SN - 978-3-941655-36-2 SP - 686 EP - 693 PB - Filtech Exhibitions Germany CY - Meerbusch ER - TY - JOUR A1 - Alexopoulos, Spiros A1 - Breitbach, Gerd A1 - Hoffschmidt, Bernhard A1 - Stobbe, P. T1 - Computational fluid flow of porous resic ceramic filtering modules and optimization of the channel edge form geometry JF - Proceedings : April 14 - 18, 2008, Leipzig, Germany / hosted by VDI, Society for Chemical and Process Engineering . Vol 2 Y1 - 2008 N1 - Verein Deutscher Ingenieure ; World Filtration Congress ; (10 : ; 2008.04.14-18 : ; Leipzig) ; WFC ; (10 : ; 2008.04.14-18 : ; Leipzig) SP - 300 EP - 304 PB - Filtech Exhibitions CY - Meerbusch ER -