TY  - JOUR
A1  - Topçu, Murat
A1  - Madabhushi, Gopal S.P.
A1  - Staat, Manfred
T1  - A generalized shear-lag theory for elastic stress transfer between matrix and fibres having a variable radius
JF  - International Journal of Solids and Structures
N2  - A generalized shear-lag theory for fibres with variable radius is developed to analyse elastic fibre/matrix stress transfer. The theory accounts for the reinforcement of biological composites, such as soft tissue and bone tissue, as well as for the reinforcement of technical composite materials, such as fibre-reinforced polymers (FRP). The original shear-lag theory proposed by Cox in 1952 is generalized for fibres with variable radius and with symmetric and asymmetric ends. Analytical solutions are derived for the distribution of axial and interfacial shear stress in cylindrical and elliptical fibres, as well as conical and paraboloidal fibres with asymmetric ends. Additionally, the distribution of axial and interfacial shear stress for conical and paraboloidal fibres with symmetric ends are numerically predicted. The results are compared with solutions from axisymmetric finite element models. A parameter study is performed, to investigate the suitability of alternative fibre geometries for use in FRP.
KW  - Natural fibres
KW  - Polymer-matrix composites
KW  - Biocomposites
KW  - Stress concentrations
KW  - Finite element analysis
Y1  - 2022
U6  - http://dx.doi.org/10.1016/j.ijsolstr.2022.111464
SN  - 0020-7683
VL  - 239–240
IS  - Art. No. 111464
PB  - Elsevier
CY  - New York, NY
ER  - 
TY  - JOUR
A1  - Werfel, Stanislas
A1  - Günthner, Roman
A1  - Hapfelmeier, Alexander
A1  - Hanssen, Henner
A1  - Kotliar, Konstantin
A1  - Heemann, Uwe
A1  - Schmaderer, Christoph
ED  - Guzik, Tomasz J.
T1  - Identification of cardiovascular high-risk groups from dynamic retinal vessel signals using untargeted machine learning
JF  - Cardiovascular Research
N2  - Dynamic retinal vessel analysis (DVA) provides a non-invasive way to assess microvascular function in patients and potentially to improve predictions of individual cardiovascular (CV) risk. The aim of our study was to use untargeted machine learning on DVA in order to improve CV mortality prediction and identify corresponding response alterations.
KW  - Machine learning
KW  - Retinal vessels
KW  - Microcirculation
KW  - Haemodialysis
KW  - Myocardial infarction and cardiac death
Y1  - 2022
U6  - http://dx.doi.org/10.1093/cvr/cvab040
SN  - 0008-6363
VL  - 118
IS  - 2
SP  - 612
EP  - 621
PB  - Oxford University Press
CY  - Oxford
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  - Kuerten, David
A1  - Kotliar, Konstantin
A1  - Fuest, Matthias
A1  - Walter, Peter
A1  - Hollstein, Muriel
A1  - Plange, Niklas
ED  - Neri, Piergiorgio
T1  - Does hemispheric vascular regulation differ significantly in glaucoma patients with altitudinal visual field asymmetry? A single-center, prospective study
JF  - International Ophthalmology
N2  - 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.
KW  - Glaucoma
KW  - Visual field asymmetry
KW  - Ocular blood flow
KW  - RVA
KW  - Vascular response
Y1  - 2021
SN  - 1573-2630
U6  - http://dx.doi.org/10.1007/s10792-021-01876-0
VL  - 41
IS  - 41
SP  - 3109
EP  - 3119
PB  - Springer
CY  - Berlin
ER  - 
TY  - CHAP
A1  - Kotliar, Konstantin
ED  - Pallikaris, I.
ED  - Tsilimbaris, M. K.
ED  - Dastiridou, A. I.
T1  - Ocular rigidity: clinical approach
T2  - Ocular Rigidity, Biomechanics and Hydrodynamics of the Eye
N2  - The term ocular rigidity is widely used in clinical ophthalmology. Generally it is assumed as a resistance of the whole eyeball to mechanical deformation and relates to biomechanical properties of the eye and its tissues. Basic principles and formulas for clinical tonometry, tonography and pulsatile ocular blood flow measurements are based on the concept of ocular rigidity. There is evidence for altered ocular rigidity in aging, in several eye diseases and after eye surgery. Unfortunately, there is no consensual view on ocular rigidity: it used to make a quite different sense for different people but still the same name. Foremost there is no clear consent between biomechanical engineers and ophthalmologists on the concept. Moreover ocular rigidity is occasionally characterized using various parameters with their different physical dimensions. In contrast to engineering approach, clinical approach to ocular rigidity claims to characterize the total mechanical response of the eyeball to its deformation without any detailed considerations on eye morphology or material properties of its tissues. Further to the previous chapter this section aims to describe clinical approach to ocular rigidity from the perspective of an engineer in an attempt to straighten out this concept, to show its advantages, disadvantages and various applications.
KW  - Coefficient of ocular rigidity
KW  - Eyeball
KW  - Corneo-scleral shell
KW  - Pressure-volume relationship
KW  - Differential tonometry
Y1  - 2021
SN  - 978-3-030-64422-2
U6  - http://dx.doi.org/10.1007/978-3-030-64422-2_2
SP  - 15
EP  - 43
PB  - Springer
CY  - Cham
ER  - 
TY  - CHAP
A1  - Grundmann, Jan Thimo
A1  - Bauer, Waldemar
A1  - Boden, Ralf
A1  - Ceriotti, Matteo
A1  - Chand, Suditi
A1  - Cordero, Federico
A1  - Dachwald, Bernd
A1  - Dumont, Etienne
A1  - Grimm, Christian D.
A1  - Heiligers, Jeannette
A1  - Herčík, David
A1  - Hérique, Alain
A1  - Ho, Tra-Mi
A1  - Jahnke, Rico
A1  - Kofman, Wlodek
A1  - Lange, Caroline
A1  - Lichtenheldt, Roy
A1  - McInnes, Colin
A1  - Meß, Jan-Gerd
A1  - Mikschl, Tobias
A1  - Mikulz, Eugen
A1  - Montenegro, Sergio
A1  - Moore, Iain
A1  - Pelivan, Ivanka
A1  - Peloni, Alessandro
A1  - Plettemeier, Dirk
A1  - Quantius, Dominik
A1  - Reershemius, Siebo
A1  - Renger, Thomas
A1  - Riemann, Johannes
A1  - Rogez, Yves
A1  - Ruffer, Michael
A1  - Sasaki, Kaname
A1  - Schmitz, Nicole
A1  - Seboldt, Wolfgang
A1  - Seefeldt, Patric
A1  - Spietz, Peter
A1  - Spröwitz, Tom
A1  - Sznajder, Maciej
A1  - Tóth, Norbert
A1  - Vergaaij, Merel
A1  - Viavattene, Giulia
A1  - Wejmo, Elisabet
A1  - Wiedemann, Carsten
A1  - Wolff, Friederike
A1  - Ziach, Christian
T1  - Flights are ten a sail – Re-use and commonality in the design and system engineering of small spacecraft solar sail missions with modular hardware for responsive and adaptive exploration
T2  - 70th International Astronautical Congress (IAC)
KW  - system engineering
KW  - small solar system body characterisation
KW  - small spacecraft solar sail
KW  - small spacecraft asteroid lander
KW  - responsive space
Y1  - 2019
SN  - 9781713814856
N1  - 70th International Astronautical Congress (IAC), Washington D.C., United States, 21-25 October 2019
SP  - 1
EP  - 7
ER  - 
TY  - JOUR
A1  - Hein, Andreas M.
A1  - Eubanks, T. Marshall
A1  - Lingam, Manasvi
A1  - Hibberd, Adam
A1  - Fries, Dan
A1  - Schneider, Jean
A1  - Kervella, Pierre
A1  - Kennedy, Robert
A1  - Perakis, Nikolaos
A1  - Dachwald, Bernd
T1  - Interstellar now! Missions to explore nearby interstellar objects
JF  - Advances in Space Research
N2  - The recently discovered first hyperbolic objects passing through the Solar System, 1I/’Oumuamua and 2I/Borisov, have raised the question about near term missions to Interstellar Objects. In situ spacecraft exploration of these objects will allow the direct determination of both their structure and their chemical and isotopic composition, enabling an entirely new way of studying small bodies from outside our solar system. In this paper, we map various Interstellar Object classes to mission types, demonstrating that missions to a range of Interstellar Object classes are feasible, using existing or near-term technology. We describe flyby, rendezvous and sample return missions to interstellar objects, showing various ways to explore these bodies characterizing their surface, dynamics, structure and composition. Their direct exploration will constrain their formation and history, situating them within the dynamical and chemical evolution of the Galaxy. These mission types also provide the opportunity to explore solar system bodies and perform measurements in the far outer solar system.
KW  - Interstellar objects
KW  - Trajectories
KW  - Missions
Y1  - 2022
U6  - http://dx.doi.org/10.1016/j.asr.2021.06.052
SN  - 0273-1177
VL  - 69
IS  - 1
SP  - 402
EP  - 414
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Kezerashvili, Roman Ya
A1  - Dachwald, Bernd
T1  - Preface: Solar sailing: Concepts, technology, and missions II
JF  - Advances in Space Research
Y1  - 2021
U6  - http://dx.doi.org/10.1016/j.asr.2021.01.037
SN  - 0273-1177
VL  - 67
IS  - 9
SP  - 2559
EP  - 2560
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Spietz, Peter
A1  - Spröwitz, Tom
A1  - Seefeldt, Patric
A1  - Grundmann, Jan Thimo
A1  - Jahnke, Rico
A1  - Mikschl, Tobias
A1  - Mikulz, Eugen
A1  - Montenegro, Sergio
A1  - Reershemius, Siebo
A1  - Renger, Thomas
A1  - Ruffer, Michael
A1  - Sasaki, Kaname
A1  - Sznajder, Maciej
A1  - Tóth, Norbert
A1  - Ceriotti, Matteo
A1  - Dachwald, Bernd
A1  - Macdonald, Malcolm
A1  - McInnes, Colin
A1  - Seboldt, Wolfgang
A1  - Quantius, Dominik
A1  - Bauer, Waldemar
A1  - Wiedemann, Carsten
A1  - Grimm, Christian D.
A1  - Hercik, David
A1  - Ho, Tra-Mi
A1  - Lange, Caroline
A1  - Schmitz, Nicole
T1  - Paths not taken – The Gossamer roadmap’s other options
JF  - Advances in Space Research
KW  - Solar sail
KW  - Small spacecraft
KW  - DLR-ESTEC GOSSAMER roadmap for solar sailing
KW  - GOSSAMER-1
Y1  - 2021
U6  - http://dx.doi.org/10.1016/j.asr.2021.01.044
SN  - 0273-1177
VL  - 67
IS  - 9
SP  - 2912
EP  - 2956
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - German, Laura
A1  - Mikucki, Jill A.
A1  - Welch, Susan A.
A1  - Welch, Kathleen A.
A1  - Lutton, Anthony
A1  - Dachwald, Bernd
A1  - Kowalski, Julia
A1  - Heinen, Dirk
A1  - Feldmann, Marco
A1  - Francke, Gero
A1  - Espe, Clemens
A1  - Lyons, W. Berry
T1  - Validation of sampling antarctic subglacial hypersaline waters with an electrothermal ice melting probe (IceMole) for environmental analytical geochemistry
JF  - International Journal of Environmental Analytical Chemistry
N2  - Geochemical characterisation of hypersaline waters is difficult as high concentrations of salts hinder the analysis of constituents at low concentrations, such as trace metals, and the collection of samples for trace metal analysis in natural waters can be easily contaminated. This is particularly the case if samples are collected by non-conventional techniques such as those required for aquatic subglacial environments. In this paper we present the first analysis of a subglacial brine from Taylor Valley, (~ 78°S), Antarctica for the trace metals: Ba, Co, Mo, Rb, Sr, V, and U. Samples were collected englacially using an electrothermal melting probe called the IceMole. This probe uses differential heating of a copper head as well as the probe’s sidewalls and an ice screw at the melting head to move through glacier ice. Detailed blanks, meltwater, and subglacial brine samples were collected to evaluate the impact of the IceMole and the borehole pump, the melting and collection process, filtration, and storage on the geochemistry of the samples collected by this device. Comparisons between melt water profiles through the glacier ice and blank analysis, with published studies on ice geochemistry, suggest the potential for minor contributions of some species Rb, As, Co, Mn, Ni, NH4+, and NO2−+NO3− from the IceMole. The ability to conduct detailed chemical analyses of subglacial fluids collected with melting probes is critical for the future exploration of the hundreds of deep subglacial lakes in Antarctica.
Y1  - 2021
U6  - http://dx.doi.org/10.1080/03067319.2019.1704750
SN  - 0306-7319
VL  - 101
IS  - 15
SP  - 2654
EP  - 2667
PB  - Taylor & Francis
CY  - London
ER  -