@incollection{TranTranMatthiesetal.2017, author = {Tran, N. T. and Tran, Thanh Ngoc and Matthies, M. G. and Stavroulakis, G. E. and Staat, Manfred}, title = {Shakedown Analysis Under Stochastic Uncertainty by Chance Constrained Programming}, series = {Advances in Direct Methods for Materials and Structures}, booktitle = {Advances in Direct Methods for Materials and Structures}, publisher = {Springer}, address = {Cham}, isbn = {978-3-319-59810-9}, doi = {10.1007/978-3-319-59810-9_6}, pages = {85 -- 103}, year = {2017}, abstract = {In this paper we propose a stochastic programming method to analyse limit and shakedown of structures under uncertainty condition of strength. Based on the duality theory, the shakedown load multiplier formulated by the kinematic theorem is proved actually to be the dual form of the shakedown load multiplier formulated by static theorem. In this investigation a dual chance constrained programming algorithm is developed to calculate simultaneously both the upper and lower bounds of the plastic collapse limit and the shakedown limit. The edge-based smoothed finite element method (ES-FEM) with three-node linear triangular elements is used for structural analysis.}, language = {en} } @article{RoehlenPilasSchoeningetal.2017, author = {R{\"o}hlen, Desiree and Pilas, Johanna and Sch{\"o}ning, Michael Josef and Selmer, Thorsten}, title = {Development of an amperometric biosensor platform for the combined determination of l-Malic, Fumaric, and l-Aspartic acid}, series = {Applied Biochemistry and Biotechnology}, volume = {183}, journal = {Applied Biochemistry and Biotechnology}, publisher = {Springer}, address = {Berlin}, issn = {1559-0291}, doi = {10.1007/s12010-017-2578-1}, pages = {566 -- 581}, year = {2017}, abstract = {Three amperometric biosensors have been developed for the detection of L-malic acid, fumaric acid, and L -aspartic acid, all based on the combination of a malate-specific dehydrogenase (MDH, EC 1.1.1.37) and diaphorase (DIA, EC 1.8.1.4). The stepwise expansion of the malate platform with the enzymes fumarate hydratase (FH, EC 4.2.1.2) and aspartate ammonia-lyase (ASPA, EC 4.3.1.1) resulted in multi-enzyme reaction cascades and, thus, augmentation of the substrate spectrum of the sensors. Electrochemical measurements were carried out in presence of the cofactor β-nicotinamide adenine dinucleotide (NAD+) and the redox mediator hexacyanoferrate (III) (HCFIII). The amperometric detection is mediated by oxidation of hexacyanoferrate (II) (HCFII) at an applied potential of + 0.3 V vs. Ag/AgCl. For each biosensor, optimum working conditions were defined by adjustment of cofactor concentrations, buffer pH, and immobilization procedure. Under these improved conditions, amperometric responses were linear up to 3.0 mM for L-malate and fumarate, respectively, with a corresponding sensitivity of 0.7 μA mM-1 (L-malate biosensor) and 0.4 μA mM-1 (fumarate biosensor). The L-aspartate detection system displayed a linear range of 1.0-10.0 mM with a sensitivity of 0.09 μA mM-1. The sensor characteristics suggest that the developed platform provides a promising method for the detection and differentiation of the three substrates.}, language = {en} } @article{GaribaldiBegingCaneseetal.2017, author = {Garibaldi, F. and Beging, Stefan and Canese, R. and Carpinelli, G. and Clinthorne, N. and Colilli, S. and Cosentino, L. and Finocchiaro, P. and Giuliani, F. and Gricia, M. and Lucentini, M. and Majewski, S. and Monno, E. and Musico, P. and Santavenere, F. and T{\"o}dter, J. and Wegener, Hans-Peter and Ziemons, Karl}, title = {A novel TOF-PET MRI detector for diagnosis and follow up of the prostate cancer}, series = {European Physical Journal Plus}, volume = {132}, journal = {European Physical Journal Plus}, number = {9}, publisher = {Springer}, address = {Berlin}, issn = {2190-5444}, doi = {10.1140/epjp/i2017-11662-x}, year = {2017}, language = {en} } @incollection{BhattaraiFrotscherStaat2018, author = {Bhattarai, Aroj and Frotscher, Ralf and Staat, Manfred}, title = {Computational Analysis of Pelvic Floor Dysfunction}, series = {Women's Health and Biomechanics}, booktitle = {Women's Health and Biomechanics}, publisher = {Springer}, address = {Cham}, isbn = {978-3-319-71574-2}, doi = {10.1007/978-3-319-71574-2_17}, pages = {217 -- 230}, year = {2018}, abstract = {Pelvic floor dysfunction (PFD) is characterized by the failure of the levator ani (LA) muscle to maintain the pelvic hiatus, resulting in the descent of the pelvic organs below the pubococcygeal line. This chapter adopts the modified Humphrey material model to consider the effect of the muscle fiber on passive stretching of the LA muscle. The deformation of the LA muscle subjected to intra-abdominal pressure during Valsalva maneuver is compared with the magnetic resonance imaging (MRI) examination of a nulliparous female. Numerical result shows that the fiber-based Humphrey model simulates the muscle behavior better than isotropic constitutive models. Greater posterior movement of the LA muscle widens the levator hiatus due to lack of support from the anococcygeal ligament and the perineal structure as a consequence of birth-related injury and aging. Old and multiparous females with uncontrolled urogenital and rectal hiatus tend to develop PFDs such as prolapse and incontinence.}, language = {en} } @incollection{BhattaraiStaat2018, author = {Bhattarai, Aroj and Staat, Manfred}, title = {Mechanics of soft tissue reactions to textile mesh implants}, series = {Biological, Physical and Technical Basics of Cell Engineering}, booktitle = {Biological, Physical and Technical Basics of Cell Engineering}, editor = {Artmann, Gerhard and Temiz Artmann, Ayseg{\"u}l and Zhubanova, Azhar A. and Digel, Ilya}, publisher = {Springer}, address = {Singapore}, isbn = {978-981-10-7904-7}, doi = {10.1007/978-981-10-7904-7_11}, pages = {251 -- 275}, year = {2018}, abstract = {For pelvic floor disorders that cannot be treated with non-surgical procedures, minimally invasive surgery has become a more frequent and safer repair procedure. More than 20 million prosthetic meshes are implanted each year worldwide. The simple selection of a single synthetic mesh construction for any level and type of pelvic floor dysfunctions without adopting the design to specific requirements increase the risks for mesh related complications. Adverse events are closely related to chronic foreign body reaction, with enhanced formation of scar tissue around the surgical meshes, manifested as pain, mesh erosion in adjacent structures (with organ tissue cut), mesh shrinkage, mesh rejection and eventually recurrence. Such events, especially scar formation depend on effective porosity of the mesh, which decreases discontinuously at a critical stretch when pore areas decrease making the surgical reconstruction ineffective that further augments the re-operation costs. The extent of fibrotic reaction is increased with higher amount of foreign body material, larger surface, small pore size or with inadequate textile elasticity. Standardized studies of different meshes are essential to evaluate influencing factors for the failure and success of the reconstruction. Measurements of elasticity and tensile strength have to consider the mesh anisotropy as result of the textile structure. An appropriate mesh then should show some integration with limited scar reaction and preserved pores that are filled with local fat tissue. This chapter reviews various tissue reactions to different monofilament mesh implants that are used for incontinence and hernia repairs and study their mechanical behavior. This helps to predict the functional and biological outcomes after tissue reinforcement with meshes and permits further optimization of the meshes for the specific indications to improve the success of the surgical treatment.}, language = {en} } @incollection{DuongSeifarthTemizArtmannetal.2018, author = {Duong, Minh Tuan and Seifarth, Volker and Temiz Artmann, Ayseg{\"u}l and Artmann, Gerhard and Staat, Manfred}, title = {Growth Modelling Promoting Mechanical Stimulation of Smooth Muscle Cells of Porcine Tubular Organs in a Fibrin-PVDF Scaffold}, series = {Biological, Physical and Technical Basics of Cell Engineering}, booktitle = {Biological, Physical and Technical Basics of Cell Engineering}, editor = {Artmann, Gerhard and Temiz Artmann, Ayseg{\"u}l and Zhubanova, Azhar A. and Digel, Ilya}, publisher = {Springer}, address = {Singapore}, isbn = {978-981-10-7904-7}, doi = {10.1007/978-981-10-7904-7_9}, pages = {209 -- 232}, year = {2018}, abstract = {Reconstructive surgery and tissue replacements like ureters or bladders reconstruction have been recently studied, taking into account growth and remodelling of cells since living cells are capable of growing, adapting, remodelling or degrading and restoring in order to deform and respond to stimuli. Hence, shapes of ureters or bladders and their microstructure change during growth and these changes strongly depend on external stimuli such as training. We present the mechanical stimulation of smooth muscle cells in a tubular fibrin-PVDFA scaffold and the modelling of the growth of tissue by stimuli. To this end, mechanotransduction was performed with a kyphoplasty balloon catheter that was guided through the lumen of the tubular structure. The bursting pressure was examined to compare the stability of the incubated tissue constructs. The results showed the significant changes on tissues with training by increasing the burst pressure as a characteristic mechanical property and the smooth muscle cells were more oriented with uniformly higher density. Besides, the computational growth models also exhibited the accurate tendencies of growth of the cells under different external stimuli. Such models may lead to design standards for the better layered tissue structure in reconstructing of tubular organs characterized as composite materials such as intestines, ureters and arteries.}, language = {en} } @incollection{FrotscherStaat2018, author = {Frotscher, Ralf and Staat, Manfred}, title = {Towards Patient-Specific Computational Modeling of hiPS-Derived Cardiomyocyte Function and Drug Action}, series = {Biological, Physical and Technical Basics of Cell Engineering}, booktitle = {Biological, Physical and Technical Basics of Cell Engineering}, editor = {Artmann, Gerhard and Temiz Artmann, Ayseg{\"u}l and Zhubanova, Azhar A. and Digel, Ilya}, publisher = {Springer}, address = {Singapore}, isbn = {978-981-10-7904-7}, doi = {10.1007/978-981-10-7904-7_10}, pages = {233 -- 250}, year = {2018}, abstract = {Human-induced pluripotent stem cell-derived cardiomyocytes (hiPS-CM) today are widely used for the investigation of normal electromechanical cardiac function, of cardiac medication and of mutations. Computational models are thus established that simulate the behavior of this kind of cells. This section first motivates the modeling of hiPS-CM and then presents and discusses several modeling approaches of microscopic and macroscopic constituents of human-induced pluripotent stem cell-derived and mature human cardiac tissue. The focus is led on the mapping of the computational results one can achieve with these models onto mature human cardiomyocyte models, the latter being the real matter of interest. Model adaptivity is the key feature that is discussed because it opens the way for modeling various biological effects like biological variability, medication, mutation and phenotypical expression. We compare the computational with experimental results with respect to normal cardiac function and with respect to inotropic and chronotropic drug effects. The section closes with a discussion on the status quo of the specificity of computational models and on what challenges have to be solved to reach patient-specificity.}, language = {en} } @incollection{DigelAkimbekovKistaubayevaetal.2018, author = {Digel, Ilya and Akimbekov, Nuraly Sh. and Kistaubayeva, Aida and Zhubanova, Azhar A.}, title = {Microbial Sampling from Dry Surfaces: Current Challenges and Solutions}, series = {Biological, Physical and Technical Basics of Cell Engineering}, booktitle = {Biological, Physical and Technical Basics of Cell Engineering}, editor = {Artmann, Gerhard and Temiz Artmann, Ayseg{\"u}l and Zhubanova, Azhar A. and Digel, Ilya}, publisher = {Springer}, address = {Singapore}, isbn = {978-981-10-7904-7}, doi = {10.1007/978-981-10-7904-7_19}, pages = {421 -- 456}, year = {2018}, abstract = {Sampling of dry surfaces for microorganisms is a main component of microbiological safety and is of critical importance in many fields including epidemiology, astrobiology as well as numerous branches of medical and food manufacturing. Aspects of biofilm formation, analysis and removal in aqueous solutions have been thoroughly discussed in literature. In contrast, microbial communities on air-exposed (dry) surfaces have received significantly less attention. Diverse surface sampling methods have been developed in order to address various surfaces and microbial groups, but they notoriously show poor repeatability, low recovery rates and suffer from lack of mutual consistency. Quantitative sampling for viable microorganisms represents a particular challenge, especially on porous and irregular surfaces. Therefore, it is essential to examine in depth the factors involved in microorganisms' recovery efficiency and accuracy depending on the sampling technique used. Microbial colonization, retention and community composition on different dry surfaces are very complex and rely on numerous physicochemical and biological factors. This study is devoted to analyze and review the (a) physical phenomena and intermolecular forces relevant for microbiological surface sampling; (b) challenges and problems faced by existing sampling methods for viable microorganisms and (c) current directions of engineering and research aimed at improvement of quality and efficiency of microbiological surface sampling.}, language = {en} } @article{Dikta2017, author = {Dikta, Gerhard}, title = {Semi-parametric random censorship models}, series = {From Statistics to Mathematical Finance : Festschrift in Honour of Winfried Stute}, journal = {From Statistics to Mathematical Finance : Festschrift in Honour of Winfried Stute}, publisher = {Springer}, address = {Berlin}, isbn = {978-3-319-50986-0}, doi = {10.1007/978-3-319-50986-0_3}, pages = {43 -- 56}, year = {2017}, language = {en} } @incollection{YoshinobuKrauseMiyamotoetal.2018, author = {Yoshinobu, Tatsuo and Krause, Steffi and Miyamoto, Ko-ichiro and Werner, Frederik and Poghossian, Arshak and Wagner, Torsten and Sch{\"o}ning, Michael Josef}, title = {(Bio-)chemical Sensing and Imaging by LAPS and SPIM}, series = {Label-free biosensing: advanced materials, devices and applications}, booktitle = {Label-free biosensing: advanced materials, devices and applications}, publisher = {Springer}, address = {Cham}, isbn = {978-3-319-75219-8}, pages = {103 -- 132}, year = {2018}, abstract = {The light-addressable potentiometric sensor (LAPS) and scanning photo-induced impedance microscopy (SPIM) are two closely related methods to visualise the distributions of chemical species and impedance, respectively, at the interface between the sensing surface and the sample solution. They both have the same field-effect structure based on a semiconductor, which allows spatially resolved and label-free measurement of chemical species and impedance in the form of a photocurrent signal generated by a scanning light beam. In this article, the principles and various operation modes of LAPS and SPIM, functionalisation of the sensing surface for measuring various species, LAPS-based chemical imaging and high-resolution sensors based on silicon-on-sapphire substrates are described and discussed, focusing on their technical details and prospective applications.}, language = {en} } @article{VoegeleRuebbelkeGovorukhaetal.2019, author = {V{\"o}gele, Stefan and R{\"u}bbelke, Dirk and Govorukha, Kristina and Grajewski, Matthias}, title = {Socio-technical scenarios for energy-intensive industries: the future of steel production in Germany}, series = {Climatic Change}, journal = {Climatic Change}, publisher = {Springer}, address = {Berlin}, issn = {0165-0009}, doi = {10.1007/s10584-019-02366-0}, pages = {1 -- 16}, year = {2019}, language = {en} } @article{Stulpe2019, author = {Stulpe, Werner}, title = {Aspects of the Quantum-Classical Connection Based on Statistical Maps}, series = {Foundations of Physics}, volume = {49}, journal = {Foundations of Physics}, number = {6}, publisher = {Springer}, address = {Berlin}, doi = {10.1007/s10701-019-00269-9}, pages = {677 -- 692}, year = {2019}, language = {en} } @article{KromeHoeftSander2019, author = {Krome, Cornelia and H{\"o}ft, Jan and Sander, Volker}, title = {Clustering time series applied to energy markets}, series = {Energy Informatics}, volume = {2}, journal = {Energy Informatics}, number = {Article numer 17}, publisher = {Springer}, address = {Berlin}, issn = {2520-8942}, doi = {10.1186/s42162-019-0076-0}, pages = {1 -- 20}, year = {2019}, language = {en} } @incollection{Kotliar2021, author = {Kotliar, Konstantin}, title = {Ocular rigidity: clinical approach}, series = {Ocular Rigidity, Biomechanics and Hydrodynamics of the Eye}, booktitle = {Ocular Rigidity, Biomechanics and Hydrodynamics of the Eye}, editor = {Pallikaris, I. and Tsilimbaris, M. K. and Dastiridou, A. I.}, publisher = {Springer}, address = {Cham}, isbn = {978-3-030-64422-2}, doi = {10.1007/978-3-030-64422-2_2}, pages = {15 -- 43}, year = {2021}, abstract = {The term ocular rigidity is widely used in clinical ophthalmology. Generally it is assumed as a resistance of the whole eyeball to mechanical deformation and relates to biomechanical properties of the eye and its tissues. Basic principles and formulas for clinical tonometry, tonography and pulsatile ocular blood flow measurements are based on the concept of ocular rigidity. There is evidence for altered ocular rigidity in aging, in several eye diseases and after eye surgery. Unfortunately, there is no consensual view on ocular rigidity: it used to make a quite different sense for different people but still the same name. Foremost there is no clear consent between biomechanical engineers and ophthalmologists on the concept. Moreover ocular rigidity is occasionally characterized using various parameters with their different physical dimensions. In contrast to engineering approach, clinical approach to ocular rigidity claims to characterize the total mechanical response of the eyeball to its deformation without any detailed considerations on eye morphology or material properties of its tissues. Further to the previous chapter this section aims to describe clinical approach to ocular rigidity from the perspective of an engineer in an attempt to straighten out this concept, to show its advantages, disadvantages and various applications.}, language = {en} } @article{KuertenKotliarFuestetal.2021, author = {Kuerten, David and Kotliar, Konstantin and Fuest, Matthias and Walter, Peter and Hollstein, Muriel and Plange, Niklas}, title = {Does hemispheric vascular regulation differ significantly in glaucoma patients with altitudinal visual field asymmetry? A single-center, prospective study}, series = {International Ophthalmology}, volume = {41}, journal = {International Ophthalmology}, number = {41}, editor = {Neri, Piergiorgio}, publisher = {Springer}, address = {Berlin}, isbn = {1573-2630}, doi = {10.1007/s10792-021-01876-0}, pages = {3109 -- 3119}, year = {2021}, abstract = {Purpose Vascular risk factors and ocular perfusion are heatedly discussed in the pathogenesis of glaucoma. The retinal vessel analyzer (RVA, IMEDOS Systems, Germany) allows noninvasive measurement of retinal vessel regulation. Significant differences especially in the veins between healthy subjects and patients suffering from glaucoma were previously reported. In this pilot-study we investigated if localized vascular regulation is altered in glaucoma patients with altitudinal visual field defect asymmetry. Methods 15 eyes of 12 glaucoma patients with advanced altitudinal visual field defect asymmetry were included. The mean defect was calculated for each hemisphere separately (-20.99 ± 10.49 pro- found hemispheric visual field defect vs -7.36 ± 3.97 dB less profound hemisphere). After pupil dilation, RVA measurements of retinal arteries and veins were conducted using the standard protocol. The superior and inferior retinal vessel reactivity were measured consecutively in each eye. Results Significant differences were recorded in venous vessel constriction after flicker light stimulation and overall amplitude of the reaction (p \ 0.04 and p \ 0.02 respectively) in-between the hemispheres spheres. Vessel reaction was higher in the hemisphere corresponding to the more advanced visual field defect. Arterial diameters reacted similarly, failing to reach statistical significance. Conclusion Localized retinal vessel regulation is significantly altered in glaucoma patients with asymmetri altitudinal visual field defects. Veins supplying the hemisphere concordant to a less profound visual field defect show diminished diameter changes. Vascular dysregulation might be particularly important in early glaucoma stages prior to a significant visual field defect.}, language = {en} } @article{LenzKahmannBehbahanietal.2022, author = {Lenz, Maximilian and Kahmann, Stephanie Lucina and Behbahani, Mehdi and Pennig, Lenhard and Hackl, Michael and Leschinger, Tim and M{\"u}ller, Lars Peter and Wegmann, Kilian}, title = {Influence of rotator cuff preload on fracture configuration in proximal humerus fractures: a proof of concept for fracture simulation}, series = {Archives of Orthopaedic and Trauma Surgery}, journal = {Archives of Orthopaedic and Trauma Surgery}, publisher = {Springer}, address = {Berlin, Heidelberg}, issn = {1434-3916}, doi = {10.1007/s00402-022-04471-9}, year = {2022}, abstract = {Introduction In regard of surgical training, the reproducible simulation of life-like proximal humerus fractures in human cadaveric specimens is desirable. The aim of the present study was to develop a technique that allows simulation of realistic proximal humerus fractures and to analyse the influence of rotator cuff preload on the generated lesions in regards of fracture configuration. Materials and methods Ten cadaveric specimens (6 left, 4 right) were fractured using a custom-made drop-test bench, in two groups. Five specimens were fractured without rotator cuff preload, while the other five were fractured with the tendons of the rotator cuff preloaded with 2 kg each. The humeral shaft and the shortened scapula were potted. The humerus was positioned at 90° of abduction and 10° of internal rotation to simulate a fall on the elevated arm. In two specimens of each group, the emergence of the fractures was documented with high-speed video imaging. Pre-fracture radiographs were taken to evaluate the deltoid-tuberosity index as a measure of bone density. Post-fracture X-rays and CT scans were performed to define the exact fracture configurations. Neer's classification was used to analyse the fractures. Results In all ten cadaveric specimens life-like proximal humerus fractures were achieved. Two III-part and three IV-part fractures resulted in each group. The preloading of the rotator cuff muscles had no further influence on the fracture configuration. High-speed videos of the fracture simulation revealed identical fracture mechanisms for both groups. We observed a two-step fracture mechanism, with initial impaction of the head segment against the glenoid followed by fracturing of the head and the tuberosities and then with further impaction of the shaft against the acromion, which lead to separation of the tuberosities. Conclusion A high energetic axial impulse can reliably induce realistic proximal humerus fractures in cadaveric specimens. The preload of the rotator cuff muscles had no influence on initial fracture configuration. Therefore, fracture simulation in the proximal humerus is less elaborate. Using the presented technique, pre-fractured specimens are available for real-life surgical education.}, language = {en} } @article{SchneiderSchwabedalBialonski2022, author = {Schneider, Jules and Schwabedal, Justus T. C. and Bialonski, Stephan}, title = {Schlafspindeln - Funktion, Detektion und Nutzung als Biomarker f{\"u}r die psychiatrische Diagnostik}, series = {Der Nervenarzt}, journal = {Der Nervenarzt}, publisher = {Springer}, address = {Berlin, Heidelberg}, issn = {1433-0407}, doi = {10.1007/s00115-022-01340-z}, pages = {1 -- 8}, year = {2022}, abstract = {Hintergrund: Die Schlafspindel ist ein Graphoelement des Elektroenzephalogramms (EEG), das im Leicht- und Tiefschlaf beobachtet werden kann. Ver{\"a}nderungen der Spindelaktivit{\"a}t wurden f{\"u}r verschiedene psychiatrische Erkrankungen beschrieben. Schlafspindeln zeigen aufgrund ihrer relativ konstanten Eigenschaften Potenzial als Biomarker in der psychiatrischen Diagnostik. Methode: Dieser Beitrag liefert einen {\"U}berblick {\"u}ber den Stand der Wissenschaft zu Eigenschaften und Funktionen der Schlafspindeln sowie {\"u}ber beschriebene Ver{\"a}nderungen der Spindelaktivit{\"a}t bei psychiatrischen Erkrankungen. Verschiedene methodische Ans{\"a}tze und Ausblicke zur Spindeldetektion werden hinsichtlich deren Anwendungspotenzial in der psychiatrischen Diagnostik erl{\"a}utert. Ergebnisse und Schlussfolgerung: W{\"a}hrend Ver{\"a}nderungen der Spindelaktivit{\"a}t bei psychiatrischen Erkrankungen beschrieben wurden, ist deren exaktes Potenzial f{\"u}r die psychiatrische Diagnostik noch nicht ausreichend erforscht. Diesbez{\"u}glicher Erkenntnisgewinn wird in der Forschung gegenw{\"a}rtig durch ressourcenintensive und fehleranf{\"a}llige Methoden zur manuellen oder automatisierten Spindeldetektion ausgebremst. Neuere Detektionsans{\"a}tze, die auf Deep-Learning-Verfahren basieren, k{\"o}nnten die Schwierigkeiten bisheriger Detektionsmethoden {\"u}berwinden und damit neue M{\"o}glichkeiten f{\"u}r die praktisch}, language = {de} } @incollection{BozakovSander2013, author = {Bozakov, Zdravko and Sander, Volker}, title = {OpenFlow: A Perspective for Building Versatile Networks}, series = {Network-Embedded Management and Applications}, booktitle = {Network-Embedded Management and Applications}, publisher = {Springer}, address = {New York, NY}, isbn = {978-1-4419-6769-5}, doi = {10.1007/978-1-4419-6769-5_11}, pages = {217 -- 245}, year = {2013}, language = {en} } @article{HugenrothBorchardtRitteretal.2021, author = {Hugenroth, Kristin and Borchardt, Ralf and Ritter, Philine and Groß‑Hardt, Sascha and Meyns, Bart and Verbelen, Tom and Steinseifer, Ulrich and Kaufmann, Tim A. S. and Engelmann, Ulrich M.}, title = {Optimizing cerebral perfusion and hemodynamics during cardiopulmonary bypass through cannula design combining in silico, in vitro and in vivo input}, series = {Scientific Reports}, volume = {11}, journal = {Scientific Reports}, number = {Art. No. 16800}, publisher = {Springer}, address = {Berlin}, issn = {2045-2322}, doi = {10.1038/s41598-021-96397-2}, pages = {1 -- 12}, year = {2021}, abstract = {Cardiopulmonary bypass (CPB) is a standard technique for cardiac surgery, but comes with the risk of severe neurological complications (e.g. stroke) caused by embolisms and/or reduced cerebral perfusion. We report on an aortic cannula prototype design (optiCAN) with helical outflow and jet-splitting dispersion tip that could reduce the risk of embolic events and restores cerebral perfusion to 97.5\% of physiological flow during CPB in vivo, whereas a commercial curved-tip cannula yields 74.6\%. In further in vitro comparison, pressure loss and hemolysis parameters of optiCAN remain unaffected. Results are reproducibly confirmed in silico for an exemplary human aortic anatomy via computational fluid dynamics (CFD) simulations. Based on CFD simulations, we firstly show that optiCAN design improves aortic root washout, which reduces the risk of thromboembolism. Secondly, we identify regions of the aortic intima with increased risk of plaque release by correlating areas of enhanced plaque growth and high wall shear stresses (WSS). From this we propose another easy-to-manufacture cannula design (opti2CAN) that decreases areas burdened by high WSS, while preserving physiological cerebral flow and favorable hemodynamics. With this novel cannula design, we propose a cannulation option to reduce neurological complications and the prevalence of stroke in high-risk patients after CPB.}, language = {en} } @article{PoghossianWeilCherstvyetal.2013, author = {Poghossian, Arshak and Weil, M. and Cherstvy, A. G. and Sch{\"o}ning, Michael Josef}, title = {Electrical monitoring of polyelectrolyte multilayer formation by means of capacitive field-effect devices}, series = {Analytical and bioanalytical chemistry}, volume = {405}, journal = {Analytical and bioanalytical chemistry}, number = {20}, publisher = {Springer}, address = {Berlin}, issn = {1432-1130 ; 1618-2642}, doi = {10.1007/s00216-013-6951-9}, pages = {6425 -- 6436}, year = {2013}, abstract = {The semiconductor field-effect platform represents a powerful tool for detecting the adsorption and binding of charged macromolecules with direct electrical readout. In this work, a capacitive electrolyte-insulator-semiconductor (EIS) field-effect sensor consisting of an Al-p-Si-SiO2 structure has been applied for real-time in situ electrical monitoring of the layer-by-layer formation of polyelectrolyte (PE) multilayers (PEM). The PEMs were deposited directly onto the SiO2 surface without any precursor layer or drying procedures. Anionic poly(sodium 4-styrene sulfonate) and cationic weak polyelectrolyte poly(allylamine hydrochloride) have been chosen as a model system. The effect of the ionic strength of the solution, polyelectrolyte concentration, number and polarity of the PE layers on the characteristics of the PEM-modified EIS sensors have been studied by means of capacitance-voltage and constant-capacitance methods. In addition, the thickness, surface morphology, roughness and wettabilityof the PE mono- and multilayers have been characterised by ellipsometry, atomic force microscopy and water contact-angle methods, respectively. To explain potential oscillations on the gate surface and signal behaviour of the capacitive field-effect EIS sensor modified with a PEM, a simplified electrostatic model that takes into account the reduced electrostatic screening of PE charges by mobile ions within the PEM has been proposed and discussed.}, language = {en} }