@article{ScheerKapelyukhRodeetal.2012, author = {Scheer, Nico and Kapelyukh, Yury and Rode, Anja and Buechel, Sandra and Wolf, C. Roland}, title = {Generation and characterization of novel cytochrome P450 Cyp2c gene cluster knockout and CYP2C9 humanized mouse lines}, series = {Molecular Pharmacology}, volume = {82}, journal = {Molecular Pharmacology}, number = {6}, publisher = {ASPET}, address = {Bethesda, Md.}, issn = {1521-0111}, doi = {10.1124/mol.112.080036}, pages = {1022 -- 1029}, year = {2012}, abstract = {Compared with rodents and many other animal species, the human cytochrome P450 (P450) Cyp2c gene cluster varies significantly in the multiplicity of functional genes and in the substrate specificity of its enzymes. As a consequence, the use of wild-type animal models to predict the role of human CYP2C enzymes in drug metabolism and drug-drug interactions is limited. Within the human CYP2C cluster CYP2C9 is of particular importance, because it is one of the most abundant P450 enzymes in human liver, and it is involved in the metabolism of a wide variety of important drugs and environmental chemicals. To investigate the in vivo functions of cytochrome P450 Cyp2c genes and to establish a model for studying the functions of CYP2C9 in vivo, we have generated a mouse model with a deletion of the murine Cyp2c gene cluster and a corresponding humanized model expressing CYP2C9 specifically in the liver. Despite the high number of functional genes in the mouse Cyp2c cluster and the reported roles of some of these proteins in different biological processes, mice deleted for Cyp2c genes were viable and fertile but showed certain phenotypic alterations in the liver. The expression of CYP2C9 in the liver also resulted in viable animals active in the metabolism and disposition of a number of CYP2C9 substrates. These mouse lines provide a powerful tool for studying the role of Cyp2c genes and of CYP2C9 in particular in drug disposition and as a factor in drug-drug interaction.}, language = {en} } @article{ScheerKapelyukhMcEwanetal.2012, author = {Scheer, Nico and Kapelyukh, Yury and McEwan, Jillian and Beuger, Vincent and Stanley, Lesley A. and Rode, Anja and Wolf, C. Roland}, title = {Modeling Human Cytochrome P450 2D6 Metabolism and Drug-drug Interaction by a Novel Panel of Knockout and Humanized Mouse Lines}, series = {Molecular Pharmacology}, volume = {81}, journal = {Molecular Pharmacology}, number = {1}, publisher = {ASPET}, address = {Bethesda, Md.}, issn = {1521-0111}, doi = {10.1124/mol.111.075192}, pages = {63 -- 72}, year = {2012}, abstract = {The highly polymorphic human cytochrome P450 2D6 enzyme is involved in the metabolism of up to 25\% of all marketed drugs and accounts for significant individual differences in response to CYP2D6 substrates. Because of the differences in the multiplicity and substrate specificity of CYP2D family members among species, it is difficult to predict pathways of human CYP2D6-dependent drug metabolism on the basis of animal studies. To create animal models that reflect the human situation more closely and that allow an in vivo assessment of the consequences of differential CYP2D6 drug metabolism, we have developed a novel straightforward approach to delete the entire murine Cyp2d gene cluster and replace it with allelic variants of human CYP2D6. By using this approach, we have generated mouse lines expressing the two frequent human protein isoforms CYP2D6.1 and CYP2D6.2 and an as yet undescribed variant of this enzyme, as well as a Cyp2d cluster knockout mouse. We demonstrate that the various transgenic mouse lines cover a wide spectrum of different human CYP2D6 metabolizer phenotypes. The novel humanization strategy described here provides a robust approach for the expression of different CYP2D6 allelic variants in transgenic mice and thus can help to evaluate potential CYP2D6-dependent interindividual differences in drug response in the context of personalized medicine.}, language = {en} } @article{ScheerBalimaneHaywardetal.2012, author = {Scheer, Nico and Balimane, Praveen and Hayward, Michael D. and Buechel, Sandra and Kauselmann, Gunther and Wolf, C. Roland}, title = {Generation and Characterization of a Novel Multidrug Resistance Protein 2 Humanized Mouse Line}, series = {Drug Metabolism and Disposition}, volume = {40}, journal = {Drug Metabolism and Disposition}, number = {11}, publisher = {ASPET}, address = {Bethesda, Md.}, issn = {1521-0111}, doi = {10.1124/dmd.112.047605}, pages = {2212 -- 2218}, year = {2012}, abstract = {The multidrug resistance protein (MRP) 2 is predominantly expressed in liver, intestine, and kidney, where it plays an important role in the excretion of a range of drugs and their metabolites or endogenous compounds into bile, feces, and urine. Mrp knockout [Mrp2(-/-)] mice have been used recently to study the role of MRP2 in drug disposition. Here, we describe the first generation and initial characterization of a mouse line humanized for MRP2 (huMRP2), which is nulled for the mouse Mrp2 gene and expresses the human transporter in the organs and cell types where MRP2 is normally expressed. Analysis of the mRNA expression for selected cytochrome P450 and transporter genes revealed no major changes in huMRP2 mice compared with wild-type controls. We show that human MRP2 is able to compensate functionally for the loss of the mouse transporter as demonstrated by comparable bilirubin levels in the humanized mice and wild-type controls, in contrast to the hyperbilirubinemia phenotype that is observed in MRP2(-/-) mice. The huMRP2 mouse provides a model to study the role of the human transporter in drug disposition and in assessing the in vivo consequences of inhibiting this transporter by compounds interacting with human MRP2.}, language = {en} } @article{RiglingBiglerEilmannetal.2012, author = {Rigling, Andreas and Bigler, Christof and Eilmann, Britta and Feldmeyer-Christe, Elisabeth and Gimmi, Urs and Ginzler, Christian and Graf, Ulrich and Mayer, Phillip and Vacchiano, Giorgio and Weber, Pascal and Wohlgemuth, Thomas and zweifel, Roman and Dobbertin, Matthias}, title = {Driving factors of a vegetation shift from Scots pine to pubescent oak in dry Alpine forests}, series = {Global Change Biology}, volume = {19}, journal = {Global Change Biology}, number = {1}, publisher = {Wiley-Blackwell}, address = {Oxford}, issn = {1354-1013 (Print)}, doi = {10.1111/gcb.12038}, pages = {229 -- 240}, year = {2012}, abstract = {An increasing number of studies have reported on forest declines and vegetation shifts triggered by drought. In the Swiss Rhone valley (Valais), one of the driest inner-Alpine regions, the species composition in low elevation forests is changing: The sub-boreal Scots pine (Pinus sylvestris L.) dominating the dry forests is showing high mortality rates. Concurrently the sub-Mediterranean pubescent oak (Quercus pubescens Willd.) has locally increased in abundance. However, it remains unclear whether this local change in species composition is part of a larger-scale vegetation shift. To study variability in mortality and regeneration in these dry forests we analysed data from the Swiss national forest inventory (NFI) on a regular grid between 1983 and 2003, and combined it with annual mortality data from a monitoring site. Pine mortality was found to be highest at low elevation (below 1000 m a.s.l.). Annual variation in pine mortality was correlated with a drought index computed for the summer months prior to observed tree death. A generalized linear mixed-effects model indicated for the NFI data increased pine mortality on dryer sites with high stand competition, particularly for small-diameter trees. Pine regeneration was low in comparison to its occurrence in the overstorey, whereas oak regeneration was comparably abundant. Although both species regenerated well at dry sites, pine regeneration was favoured at cooler sites at higher altitude and oak regeneration was more frequent at warmer sites, indicating a higher adaptation potential of oaks under future warming. Our results thus suggest that an extended shift in species composition is actually occurring in the pine forests in the Valais. The main driving factors are found to be climatic variability, particularly drought, and variability in stand structure and topography. Thus, pine forests at low elevations are developing into oak forests with unknown consequences for these ecosystems and their goods and services.}, language = {en} } @article{RibitschHeumannKarletal.2012, author = {Ribitsch, D. and Heumann, S. and Karl, W. and Gerlach, J. and Leber, R. and Birner-Gruenberger, R. and Gruber, K. and Eiteljoerg, I. and Remler, P. and Siegert, Petra and Lange, J. and Maurer, Karl-Heinz and Berg, G. and Guebitz, G. M. and Schwab, H.}, title = {Extracellular serine proteases from Stenotrophomonas maltophilia: Screening, isolation and heterologous expression in E. coli}, series = {Journal of biotechnology}, volume = {157}, journal = {Journal of biotechnology}, number = {1}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1873-4863 (E-Journal); 0168-1656 (Print)}, doi = {10.1016/j.jbiotec.2011.09.025}, pages = {140 -- 147}, year = {2012}, abstract = {A large strain collection comprising antagonistic bacteria was screened for novel detergent proteases. Several strains displayed protease activity on agar plates containing skim milk but were inactive in liquid media. Encapsulation of cells in alginate beads induced protease production. Stenotrophomonas maltophilia emerged as best performer under washing conditions. For identification of wash-active proteases, four extracellular serine proteases called StmPr1, StmPr2, StmPr3 and StmPr4 were cloned. StmPr2 and StmPr4 were sufficiently overexpressed in E. coli. Expression of StmPr1 and StmPr3 resulted in unprocessed, insoluble protein. Truncation of most of the C-terminal domain which has been identified by enzyme modeling succeeded in expression of soluble, active StmPr1 but failed in case of StmPr3. From laundry application tests StmPr2 turned out to be a highly wash-active protease at 45 °C. Specific activity of StmPr2 determined with suc-l-Ala-l-Ala-l-Pro-l-Phe-p-nitroanilide as the substrate was 17 ± 2 U/mg. In addition we determined the kinetic parameters and cleavage preferences of protease StmPr2.}, language = {en} } @article{ReisgenSchleserMokrovetal.2012, author = {Reisgen, Uwe and Schleser, Markus and Mokrov, Oleg and Zabirov, Alexander and F{\"u}ssel, Uwe and Schnick, Michael and Hertel, Martin and Jaeckel, Sebastian}, title = {Modelling and visualisation of the GMA process}, series = {Welding and Cutting}, volume = {11}, journal = {Welding and Cutting}, number = {4}, publisher = {DVS Verlag}, address = {D{\"u}sseldorf}, issn = {1612-3433}, pages = {242 -- 249}, year = {2012}, language = {en} } @article{ReisgenSchleserMokrovetal.2012, author = {Reisgen, Uwe and Schleser, Markus and Mokrov, Oleg and Ahmed, Essam}, title = {Statistical modeling of laser welding of DP/TRIP steel sheets}, series = {Optics and laser technology}, volume = {44}, journal = {Optics and laser technology}, number = {1}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1879-2545 (E-Journal); 0030-3992 (Print); 0308-4280 (Print)}, doi = {10.1016/j.optlastec.2011.05.025}, pages = {92 -- 101}, year = {2012}, abstract = {In this research work, a statistical analysis of the CO2 laser beam welding of dual phase (DP600)/transformation induced plasticity (TRIP700) steel sheets was done using response surface methodology. The analysis considered the effect of laser power (2-2.2 kW), welding speed (40-50 mm/s) and focus position (-1 to 0 mm) on the heat input, the weld bead geometry, uniaxial tensile strength, formability limited dome height and welding operation cost. The experimental design was based on Box-Behnken design using linear and quadratic polynomial equations for predicting the mathematical models. The results indicate that the proposed models predict the responses adequately within the limits of welding parameters being used and the welding speed is the most significant parameter during the welding process.}, language = {en} } @article{ReisgenSchleserMokrovetal.2012, author = {Reisgen, Uwe and Schleser, Markus and Mokrov, Oleg and Ahmed, Essam}, title = {Optimization of laser welding of DP/TRIP steel sheets using statistical approach}, series = {Optics and laser technology}, volume = {44}, journal = {Optics and laser technology}, number = {1}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1879-2545 (E-Journal); 0030-3992 (Print); 0308-4280 (Print)}, doi = {10.1016/j.optlastec.2011.06.028}, pages = {255 -- 262}, year = {2012}, abstract = {Generally, the quality of a weld joint is directly influenced by the welding input parameter settings. Selection of proper process parameters is important to obtain the desired weld bead profile and quality. In this research work, numerical and graphical optimization techniques of the CO2 laser beam welding of dual phase (DP600)/transformation induced plasticity (TRIP700) steel sheets were carried out using response surface methodology (RSM) based on Box-Behnken design. The procedure was established to improve the weld quality, increase the productivity and minimize the total operation cost by considering the welding parameters range of laser power (2-2.2 kW), welding speed (40-50 mm/s) and focus position (-1 to 0 mm). It was found that, RSM can be considered as a powerful tool in experimental welding optimization, even when the experimenter does not have a model for the process. Strong, efficient and low cost weld joints could be achieved using the optimum welding conditions.}, language = {en} } @article{ReisgenSchleserAbdurakhmanovetal.2012, author = {Reisgen, Uwe and Schleser, Markus and Abdurakhmanov, Aydemir and Turichin, Gleb and Valdaitseva, Elena and Bach, Friedrich-Wilhelm and Hassel, Thomas and Beniyashi, Alexander}, title = {Investigation of factors influencing the formation of weld defects in non-vacuum electron beam welding}, series = {The Paton welding journal}, volume = {2012}, journal = {The Paton welding journal}, number = {2}, publisher = {Paton Publishing House}, address = {Kiev}, issn = {0957-798X}, pages = {11 -- 18}, year = {2012}, abstract = {The influence of welding condition parameters and properties of material on formation of defects, such as humping and undercuts, in non-vacuum electron beam welding was investigated. The influence of separate welding parameters on the quality of welds was determined.}, language = {en} } @article{ReisgenSchleserAbdurakhmanovetal.2012, author = {Reisgen, Uwe and Schleser, Markus and Abdurakhmanov, Aydemir and Gumenyuk, Andrey}, title = {Measuring of plasma properties induced by non-vacuum electron beam welding}, series = {Physics of plasma}, volume = {19}, journal = {Physics of plasma}, number = {1}, publisher = {AIP Publishing}, address = {Melville, NY}, issn = {1089-7674 (E-Journal); 1070-664X (Print)}, doi = {10.1063/1.3675874}, pages = {1 -- 7}, year = {2012}, abstract = {Electron beam plasma measurement was realised by means of DIABEAM system invented by ISF RWTH Aachen. The Langmuir probe method is used for measurement. The relative simplicity of the method and the possibility of dispersion of high power on the probe allow its application for the investigation of high-power electron beams. The key element of the method is a rotating thin tungsten wire, which intersects the beam transversely on its axis and collects part of the current by itself. The signals, which are registered in the DIABEAM as a voltage, were taken in the form of amplitude. The conversion of the probe current into the distribution along the beam radius was realised using the Abel's method. A voltage-current characteristic was built for the beam current. The local electron density as well as the electron temperature, the floating potential and the plasma potential were measured and calculated by means of this characteristic.}, language = {en} }