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  - Spelthahn, Heiko
A1  - Schubert, Jürgen
A1  - Schöning, Michael Josef
T1  - Dünnschichtsensoren für die Schwermetallanalytik
JF  - GIT : Labor-Fachzeitschrift
N2  - Die Detektion von Schadstoffen repräsentiert in der Umweltanalytik eine wichtige Aufgabenstellung. Gerade die Abwasser- bzw. Brauchwasseranalytik sowie die Prozesskontrolle haben einen hohen Stellenwert. Siliziumbasierte Dünnschichtsensoren bieten eine kostengünstige Möglichkeit, „online“-Messungen bzw. Vor-Ort-Messungen zeitnah durchzuführen. In dieser Arbeit wird ein potentiometrisches Sensorarray auf der Basis von Chalkogenidgläsern zur Detektion von Schwermetallen in wässrigen Medien vorgestellt.
Y1  - 2012
SN  - 0016-3538
VL  - 56
IS  - 4
SP  - 285
EP  - 287
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Hüning, Felix
T1  - Using Trench PowerMOSFETs in Linear Mode
JF  - Power Electronics Europe (2012)
N2  - If we think about applications for modern Power MOSFETs using trench technology, running them in linear mode may not be top of the priority list. Yet there are multiple uses for Trench Power MOSFETs in linear mode. In fact, even turning the device on and off in switching applications is a form of linear operation. Also, these components can be run in linear mode to protect the device against voltage surges. This article will illustrate the factors that need to be considered for linear operation and show how Trench Power MOSFETs are suited to it.
Y1  - 2012
SN  - 1748-3530
SP  - 27
EP  - 29
PB  - DFA Media
CY  - Tonbridge
ER  - 
TY  - JOUR
A1  - Bohrn, U.
A1  - Stütz, E.
A1  - Fuchs, K.
A1  - Fleischer, M.
A1  - Schöning, Michael Josef
A1  - Wagner, P.
T1  - Monitoring of irritant gas using a whole-cell-based sensor system
JF  - Sensors and Actuators B: Chemical
N2  - Cell-based sensors for the detection of gases have long been underrepresented, due to the cellular requirement of being cultured in a liquid environment. In this work we established a cell-based gas biosensor for the detection of toxic substances in air, by adapting a commercial sensor chip (Bionas®), previously used for the measurement of pollutants in liquids. Cells of the respiratory tract (A549, RPMI 2650, V79), which survive at a gas phase in a natural context, are used as biological receptors. The physiological cell parameters acidification, respiration and morphology are continuously monitored in parallel. Ammonia was used as a highly water-soluble model gas to test the feasibility of the sensor system. Infrared measurements confirmed the sufficiency of the medium draining method. This sensor system provides a basis for many sensor applications such as environmental monitoring, building technology and public security.
Y1  - 2012
U6  - http://dx.doi.org/10.1016/j.snb.2012.05.088
SN  - 0925-4005
VL  - 175
SP  - 208
EP  - 217
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  - 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  - 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  - Werner, Frederik
A1  - Groebel, Simone
A1  - Krumbe, Christoph
A1  - Wagner, Torsten
A1  - Selmer, Thorsten
A1  - Yoshinobu, Tatsuo
A1  - Baumann, Marcus
A1  - Schöning, Michael Josef
T1  - Nutrient concentration-sensitive microorganism-based biosensor
JF  - Physica Status Solidi (a)
Y1  - 2012
U6  - http://dx.doi.org/10.1002/pssa.201100801
SN  - 1862-6319
VL  - 209
IS  - 5
SP  - 900
EP  - 904
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Lustfeld, H.
A1  - Pithan, C.
A1  - Reißel, Martin
T1  - Metallic electrolyte composites in the framework of the brick-layer model
JF  - Journal of the European Ceramic Society
N2  - It is well known that the already large dielectric constants of some electrolytes like BaTiO₃ can be enhanced further by adding metallic (e.g. Ni, Cu or Ag) nanoparticles. The enhancement can be quite large, a factor of more than 1000 is possible. The consequences for the properties will be discussed in the present paper applying a brick-layer model (BLM) for calculating dc-resistivities of thin layers and a modified one (PBLM) that includes percolation for calculating dielectric properties of these materials. The PBLM results in an at least qualitative description and understanding of the physical phenomena: This model gives an explanation for the steep increase of the dielectric constant below the percolation threshold and why this increase is connected to a dramatic decrease of the breakdown voltage as well as the ability of storing electrical energy. We conclude that metallic electrolyte composites like BaTiO₃ are not appropriate for energy storage.
Y1  - 2012
U6  - http://dx.doi.org/10.1016/j.jeurceramsoc.2011.10.017
SN  - 0955-2219
VL  - 32
IS  - 4
SP  - 859
EP  - 864
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Bäcker, Matthias
A1  - Raue, Markus
A1  - Schusser, Sebastian
A1  - Jeitner, C.
A1  - Breuer, L.
A1  - Wagner, P.
A1  - Poghossian, Arshak
A1  - Förster, Arnold
A1  - Mang, Thomas
A1  - Schöning, Michael Josef
T1  - Microfluidic chip with integrated microvalves based on temperature- and pH-responsive hydrogel thin films
JF  - Physica Status Solidi  (a)
N2  - Two types of microvalves based on temperature-responsive poly(N-isopropylacrylamide) (PNIPAAm) and pH-responsive poly(sodium acrylate) (PSA) hydrogel films have been developed and tested. The PNIPAAm and PSA hydrogel films were prepared by means of in situ photopolymerization directly inside the fluidic channel of a microfluidic chip fabricated by combining Si and SU-8 technologies. The swelling/shrinking properties and height changes of the PNIPAAm and PSA films inside the fluidic channel were studied at temperatures of deionized water from 14 to 36 °C and different pH values (pH 3–12) of Titrisol buffer, respectively. Additionally, in separate experiments, the lower critical solution temperature (LCST) of the PNIPAAm hydrogel was investigated by means of a differential scanning calorimetry (DSC) and a surface plasmon resonance (SPR) method. Mass-flow measurements have shown the feasibility of the prepared hydrogel films to work as an on-chip integrated temperature- or pH-responsive microvalve capable to switch the flow channel on/off.
Y1  - 2012
U6  - http://dx.doi.org/10.1002/pssa.201100763
SN  - 1862-6319
VL  - 209
IS  - 5
SP  - 839
EP  - 845
PB  - Wiley-VCH
CY  - Weinheim
ER  -