TY  - CHAP
A1  - Lanzl, I.
A1  - Seidova, S.-F.
A1  - Dühring, C. von
A1  - Kotliar, Konstantin
ED  - Erb, Carl
T1  - Befunde der dynamischen Gefäßanalyse am Auge bei Gesunden und Glaukom-Patienten mit praxisrelevanter Bedeutung
T2  - Mikrozirkulation beim Glaukom
Y1  - 2009
N1  - Search on Glaucoma
SP  - 33
EP  - 39
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Dachwald, Bernd
A1  - Ball, Andrew J.
A1  - Ulamec, Stephan
A1  - Price, Michael E.
T1  - A small mission for in situ exploration of a primitive binary near-Earth asteroid  / Ball, Andrew J. ; Ulamec, Stephan ; Dachwald, Bernd ; Price, Michael E. ; [u.a.]
JF  - Advances in Space Research. 43 (2009), H. 2
Y1  - 2009
SN  - 0273-1177
SP  - 317
EP  - 324
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Staat, Manfred
A1  - Vu, Duc Khoi
T1  - Limit analysis of flaws in pressurized pipes and cylindrical vessels Part II: Circumferential defects
JF  - Engineering Fracture Mechanics ; 97(2013), H. 1
N2  - Upper and lower bound theorems of limit analyses have been presented in part I of the paper. Part II starts with the finite element discretization of these theorems and demonstrates how both can be combined in a primal–dual optimization problem. This recently proposed numerical method is used to guide the development of a new class of closed-form limit loads for circumferential defects, which show that only large defects contribute to plastic collapse with a rapid loss of strength with increasing crack sizes. The formulae are compared with primal–dual FEM limit analyses and with burst tests. Even closer predictions are obtained with iterative limit load solutions for the von Mises yield function and for the Tresca yield function. Pressure loading of the faces of interior cracks in thick pipes reduces the collapse load of circumferential defects more than for axial flaws. Axial defects have been treated in part I of the paper.
Y1  - 2012
U6  - http://dx.doi.org/10.1016/j.engfracmech.2012.05.017
SN  - 0013-7944
VL  - 97
SP  - 314
EP  - 333
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Scholz, Christina
A1  - Romagnoli, Daniele
A1  - Dachwald, Bernd
A1  - Theil, Stephan
T1  - Performance analysis of an attitude control system for solar sails using sliding masses
JF  - Advances in Space Research
Y1  - 2011
SN  - 0273-1177
VL  - 48
IS  - 11
SP  - 1822
EP  - 1835
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Dachwald, Bernd
A1  - Wurm, Patrick
T1  - Mission analysis and performance comparison for an Advanced Solar Photon Thruster
JF  - Advances in Space Research
Y1  - 2011
SN  - 0273-1177
VL  - 48
IS  - 11
SP  - 1858
EP  - 1868
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Novacek, V.
A1  - Tran, Thanh Ngoc
A1  - Klinge, U.
A1  - Tolba, R. H.
A1  - Staat, Manfred
A1  - Bronson, D. G.
A1  - Miesse, A. M.
A1  - Whiffen, J.
A1  - Turquier, F.
T1  - Finite element modelling of stapled colorectal end-to-end anastomosis : Advantages of variable height stapler design
JF  - Journal of Biomechanics
N2  - The impact of surgical staplers on tissues has been studied mostly in an empirical manner. In this paper, finite element method was used to clarify the mechanics of tissue stapling and associated phenomena. Various stapling modalities and several designs of circular staplers were investigated to evaluate the impact of the device on tissues and mechanical performance of the end-to-end colorectal anastomosis. Numerical simulations demonstrated that a single row of staples is not adequate to resist leakage due to non-linear buckling and opening of the tissue layers between two adjacent staples. Compared to the single staple row configuration, significant increase in stress experienced by the tissue at the inner staple rows was observed in two and three rows designs. On the other hand, adding second and/or third staple row had no effect on strain in the tissue inside the staples. Variable height design with higher staples in outer rows significantly reduced the stresses and strains in outer rows when compared to the same configuration with flat cartridge.
KW  - Variable height stapler design
KW  - Anastomotic leakage
KW  - Finite element modelling
KW  - End-to-end colorectal anastomosis
KW  - Surgical staplers
Y1  - 2012
U6  - http://dx.doi.org/10.1016/j.jbiomech.2012.07.021
SN  - 1873-2380
VL  - 45
IS  - 115
SP  - 2693
EP  - 2697
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Nguyen, Nhu Huynh
A1  - Duong, Minh Tuan
A1  - Tran, Thanh Ngoc
A1  - Pham, Phu Tinh
A1  - Grottke, O.
A1  - Tolba, R.
A1  - Staat, Manfred
T1  - Influence of a freeze–thaw cycle on the stress–stretch curves of tissues of porcine abdominal organs
JF  - Journal of Biomechanics
N2  - The paper investigates both fresh porcine spleen and liver and the possible decomposition of these organs under a freeze–thaw cycle. The effect of tissue preservation condition is an important factor which should be taken into account for protracted biomechanical tests. In this work, tension tests were conducted for a large number of tissue specimens from twenty pigs divided into two groups of 10. Concretely, the first group was tested in fresh state; the other one was tested after a freeze-thaw cycle which simulates the conservation conditions before biomechanical experiments. A modified Fung model for isotropic behavior was adopted for the curve fitting of each kind of tissues. Experimental results show strong effects of the realistic freeze–thaw cycle on the capsule of elastin-rich spleen but negligible effects on the liver which virtually contains no elastin. This different behavior could be explained by the autolysis of elastin by elastolytic enzymes during the warmer period after thawing. Realistic biomechanical properties of elastin-rich organs can only be expected if really fresh tissue is tested. The observations are supported by tests of intestines.
KW  - Autolysis
KW  - Decomposition
KW  - Freeze–thaw process
KW  - Spleen
KW  - Liver
Y1  - 2012
U6  - http://dx.doi.org/10.1016/j.jbiomech.2012.07.008
SN  - 1873-2380
VL  - 45
IS  - 14
SP  - 2382
EP  - 2386
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Kurulgan Demirci, Eylem
A1  - Demirci, Taylan
A1  - Linder, Peter
A1  - Trzewik, Jürgen
A1  - Gierkowski, Jessica Ricarda
A1  - Gossmann, Matthias
A1  - Kayser, Peter
A1  - Porst, Dariusz
A1  - Digel, Ilya
A1  - Artmann, Gerhard
A1  - Temiz Artmann, Aysegül
T1  - rhAPC reduces the endothelial cell permeability via a decrease of contractile tensions induced by endothelial cells
JF  - Journal of Bioscience and Bioengineering
N2  - All cells generate contractile tension. This strain is crucial for mechanically controlling the cell shape, function and survival. In this study, the CellDrum technology quantifying cell's (the cellular) mechanical tension on a pico-scale was used to investigate the effect of lipopolysaccharide (LPS) on human aortic endothelial cell (HAoEC) tension. The LPS effect during gram-negative sepsis on endothelial cells is cell contraction causing endothelium permeability increase. The aim was to finding out whether recombinant activated protein C (rhAPC) would reverse the endothelial cell response in an in-vitro sepsis model. In this study, the established in-vitro sepsis model was confirmed by interleukin 6 (IL-6) levels at the proteomic and genomic levels by ELISA, real time-PCR and reactive oxygen species (ROS) activation by florescence staining. The thrombin cellular contraction effect on endothelial cells was used as a positive control when the CellDrum technology was applied. Additionally, the Ras homolog gene family, member A (RhoA) mRNA expression level was checked by real time-PCR to support contractile tension results. According to contractile tension results, the mechanical predominance of actin stress fibers was a reason of the increased endothelial contractile tension leading to enhanced endothelium contractility and thus permeability enhancement. The originality of this data supports firstly the basic measurement principles of the CellDrum technology and secondly that rhAPC has a beneficial effect on sepsis influenced cellular tension. The technology presented here is promising for future high-throughput cellular tension analysis that will help identify pathological contractile tension responses of cells and prove further cell in-vitro models.
KW  - Cell permeability
KW  - Cellular force
KW  - Endothelial cells
KW  - Recombinant activated protein C
KW  - Lipopolysaccharide
KW  - Contractile tension
KW  - CellDrum
Y1  - 2012
U6  - http://dx.doi.org/10.1016/j.jbiosc.2012.03.019
SN  - 1347-4421
VL  - 113
IS  - 2
SP  - 212
EP  - 219
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Hanssen, H.
A1  - Nickel, T.
A1  - Drexel, V.
A1  - Hertel, G.
A1  - Emslander, I.
A1  - Sisic, Z.
A1  - Lorang, D.
A1  - Schuster, T.
A1  - Kotliar, Konstantin
A1  - Pressler, A.
A1  - Schmidt-Trucksäss, A.
A1  - Weis, M.
A1  - Halle, M.
T1  - Exercise-induced alterations of retinal vessel diameters and cardiovascular risk reduction in obesity
JF  - Atherosclerosis
Y1  - 2011
SN  - 0021-9150
VL  - 216
IS  - 2
SP  - 433
EP  - 439
PB  - Elsevier
CY  - Amsterdam
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  -