TY - JOUR A1 - Fuchs, Sven A1 - Förster, Hans-Jürgen A1 - Braune, K. A1 - Förster, A. T1 - Calculation of Thermal Conductivity of Low-Porous, Isotropic Plutonic Rocks of the Crust at Ambient Conditions From Modal Mineralogy and Porosity BT - a Viable Alternative for Direct Measurement? JF - Journal of geophysical research : Solid earth N2 - Thermal conductivity (lambda) is an essential physical property of minerals and rocks and fundamental in constraining the thermal field of the lithosphere. In case that adequate samples to measure lambda are not available, it could be indirectly inferred from calculation. One of the most widely applied indirect methods for rocks involve modal mineralogy and porosity as parameters that are incorporated into mathematical mean or mixing models. Robust inferences from these approaches for crystalline rocks were impeded by a small number of studied samples or restriction to certain rock types. We employ this method and examine its applicability to low-porosity plutonic rocks by calculating bulk thermal conductivity lambda(b) for 45 samples covering the entire range from gabbro/diorite to granite. We show that the use of the harmonic-mean model for both rock matrix and porosity provided a good match between lambda(b.meas) and lambda(b.calc) of <10% deviation (2 sigma), with relative and absolute errors amounting to 1.49.7% and 4.44.9%, respectively. The results of our study constitute a big step forward to a robust conclusion on the overall applicability of the harmonic-mean model for inferring lambda(b) of isotropic, low-porosity, mafic to silicic plutonic and metamorphic rocks with an acceptable magnitude of error. Drill cuttings and enclaves form particularly interesting objects for application of this method, as they are poorly suited for direct measurement. Well-derived lambda values for those rocks would permit to calculate heat flow and to model more profoundly the thermal state of the deeper lithosphere. Y1 - 2018 U6 - https://doi.org/10.1029/2018JB016287 SN - 2169-9313 SN - 2169-9356 VL - 123 IS - 10 SP - 8602 EP - 8614 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Krüger-Genge, A. A1 - Braune, S. A1 - Walter, M. A1 - Krengel, M. A1 - Kratz, K. A1 - Küpper, J. H. A1 - Lendlein, Andreas A1 - Jung, Friedrich T1 - Influence of different surface treatments of poly(n-butyl acrylate) networks on fibroblasts adhesion, morphology and viability JF - Clinical hemorheology and microcirculation : blood flow and vessels N2 - BACKGROUND: Physical and chemical characteristics of implant materials determine the fate of long-term cardiovascular devices. However, there is still a lack of fundamental understanding of the molecular mechanisms occurring in the material-tissue interphase. In a previous study, soft covalently crosslinked poly(n-butyl acrylate) networks (cPnBA) were introduced as sterilizable, non-toxic and immuno-compatible biomaterials with mechanical properties adjustable to blood vessels. Here we study the influence of different surface treatments in particular oxygen plasma modification and fibrinogen deposition as well as a combinatorial approach on the adhesion and viability of fibroblasts. RESULTS: Compared to non-treated cPnBAs the advancing water-contact angles were found to be reduced after all surface modifications (p<0.05, each), while lowest values were observed after the combined surface treatment (OPT+FIB). The latter differed significantly from the single OPT and FIB. The number of adherent fibroblasts and their adherence behavior differed on both pristine cPnBA networks. The fibroblast density on cPnBA04 was 743 +/- 434 cells. mm(-2), was about 6.5 times higher than on cPnBA73 with 115 +/- 73 cells. mm(-2). On cPnBA04 about 20% of the cells were visible as very small, round and buckled cells while all other cells were in a migrating status. On cPnBA73, nearly 50% of fibroblasts were visible as very small, round and buckled cells. The surface functionalization either using oxygen plasma treatment or fibrinogen coating led to a significant increase of adherent fibroblasts, particularly the combination of both techniques, for both cPnBA networks. It is noteworthy to mention that the fibrinogen coating overruled the characteristics of the pristine surfaces; here, the fibroblast densities after seeding were identical for both cPnBAnetworks. Thus, the binding rather depended on the fibrinogen coating than on the substrate characteristics anymore. While the integrity of the fibroblasts membrane was comparable for both polymers, the MTS tests showed a decreased metabolic activity of the fibroblasts on cPnBA. CONCLUSION: The applied surface treatments of cPnBA successfully improved the adhesion of viable fibroblasts. Under resting conditions as well as after shearing the highest fibroblast densities were found on surfaces with combined post-treatment. KW - Biomaterial KW - poly(n-butyl acrylate) KW - fibroblast KW - oxygen plasma KW - fibrinogen KW - cell adhesion KW - focal adhesion KW - actin cytoskeleton KW - viability Y1 - 2018 U6 - https://doi.org/10.3233/CH-189130 SN - 1386-0291 SN - 1875-8622 VL - 69 IS - 1-2 SP - 305 EP - 316 PB - IOS Press CY - Amsterdam ER -