525 research outputs found
Small scale assessment of copepod epibionts with the Lightframe On-sight Keyspecies Investigation system (LOKI) in the Norwegian Sognefjord
During an expedition with RV Heincke in October/November 2014 twelve stations in the Norwegian Sognefjord were sampled with the Lightframe On-sight Keyspecies Investigation system (LOKI, Schulz et al. 2010). This optical sampling device allows merging of high quality in-situ image data of individual specimens with ambient environmental parameters on scales of a few centimetres. Investigating raw data for species distribution patterns it became obvious, that epibiont carrying copepods are related to specific water properties in the trough and behind the sill at the entrance of the fjord. Here we give a first peek about small scale relationships between hydrography and interactions of biota, insufficiently detectable with classical net samplings
Uncovering the Role of IS in Business Model Innovation - A Taxonomy-driven Approach to Structure the Field
Business model innovations (BMIs) are one of the key activities organizations must undertake to survive and thrive. As information systems (IS) penetrate more and more aspects of life, they become an important factor affecting both the process and the outcome of business model innovations. The increased importance of IS in a growing number of industries has led various researchers to focus on examining the role of IS in innovation. However, these insights concentrate on process, product, and service innovations, while business model innovations encompass characteristics that are fundamentally different from these. Therefore, in this paper we use a rigorous taxonomy-building approach to uncover the distinct roles IS play in this important endeavor, employing a meta-perspective and drawing from documented empirical research on business model innovations. We found that IS act, first, as enablers of business model innovation, second, as capabilities in the business model innovation process, and third, as frames of reference for business model innovations. Our findings indicate that IS are thus both operand and operant resources in business model innovations. Hence, business managers must be aware of all of these roles, as they could have transformative impacts in every industry
Orthogonal Translation Meets Electron Transfer: In Vivo Labeling of Cytochrome c for Probing Local Electric Fields
Cytochrome c (cyt c), a redox protein involved in diverse fundamental biological processes, is among the most traditional model proteins for analyzing biological electron transfer and protein dynamics both in solution and at membranes. Studying the role of electric fields in energy transduction mediated by cyt c relies upon appropriate reporter groups. Up to now these had to be introduced into cyt c by in vitro chemical modification. Here, we have overcome this restriction by incorporating the noncanonical amino acid p-cyanophenylalanine (pCNF) into cyt c in vivo. UV and CD spectroscopy indicate preservation of the overall protein fold, stability, and heme coordination, whereas a small shift of the redox potential was observed by cyclic voltammetry. The C≡N stretching mode of the incorporated pCNF detected in the IR spectra reveals a surprising difference, which is related to the oxidation state of the heme iron, thus indicating high sensitivity to changes in the electrostatics of cyt c.Fil: Völler, Jan. Technishe Universitat Berlin; AlemaniaFil: Biava, Hernan Daniel. Technishe Universitat Berlin; Alemania. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Rosario. Instituto de QuÃmica Rosario; ArgentinaFil: Koksch, Beate. Freie Universitä t Berlin; AlemaniaFil: Hildebrandt, Peter. Technishe Universitat Berlin; AlemaniaFil: Budisa, Nediljko. Technishe Universitat Berlin; Alemani
Partial hepatectomy in rats results in immediate down-regulation of p27Kip1 in residual liver tissue by transcriptional and post-translational processes
Purpose: The cyclin-dependent kinase (Cdk) inhibitor p27Kip1 may be involved in regulating re-entry of residual hepatocytes into the cell cycle upon loss of liver tissue by partial hepatectomy (PH). As yet, changes in Kip1 expression during the initial period following PH are not well-characterized. We investigated immediate changes in Kip1 mRNA and protein levels as well as changes in Kip1 phosphorylation in liver tissue within the relevant time window between surgery and the onset of DNA synthesis at 10–12 h.
Methods: We used real-time PCR, quantitative Western blotting, and immune histochemistry on tissue samples of adult rats obtained during or between 2 and 10 h after surgical removal of two thirds of the liver to analyze Kip1 mRNA or protein levels, respectively, or to quantify nuclear expression of Kip1.
Results: Kip1 mRNA was down-regulated within 4 h after PH by 60% and remained unchanged thereafter up to 10 h. With a lag phase of 2–3 h, Kip1-protein was down-regulated to a level of 40% of the control. The level of Thr187-phosphorylated Kip1 started to increase at 4 h and reached a maximum level at 8–10 h after PH. Kip1 immunoreactivity was observed in 30% of the hepatocytes before PH. Within 6–8 h after PH, more than half of the hepatocytes lost nuclear Kip1 signals. Kip1-specific micro-RNAs (miRNA221, miRNA222) were not changed upon PH.
Conclusions: A portion of hepatocytes in adult rats constitutively express Kip1 and down-regulate Kip1 immediately upon PH. This response involves transcriptional processes (loss of Kip1 mRNA) as well as accelerated degradation of existing protein (increase in pThr187-phosphorylation mediating polyubiquitinylation and proteasomal degradation of Kip1). Kip1 down-regulation occurs precisely within the intervall between surgery and onset of DNA synthesis which supports the hypothesis that it mediates activation of G0/0S-phase Cdk/cyclin-complexes and re-entry of hepatocytes into the cell cycle
A Comparison of Incremental Triple Graph Grammar Tools
Triple Graph Grammars (TGGs) are a graph-based and visual technique for specifying bidirectional model transformation. TGGs can be used to transform models from scratch (in the batch mode), but the real potential of TGGs lies in propagating updates incrementally. Existing TGG tools differ considerably in their incremental mode concerning underlying algorithms, user-oriented aspects, incremental update capabilities, and formal properties. Indeed, the different foci, strengths, and weaknesses of current TGG tools in the incremental mode are difficult to discern, especially for non-developers. In this paper, we close this gap by (i) identifying a set of criteria for a qualitative comparison of TGG tools in the incremental mode, (ii) comparing three prominent incremental TGG tools with regard to these criteria, and (iii) conducting a quantitative comparison by means of runtime measurements
Photometric Redshift Calibration with Self Organising Maps
Accurate photometric redshift calibration is central to the robustness of all
cosmology constraints from cosmic shear surveys. Analyses of the KiDS
re-weighted training samples from all overlapping spectroscopic surveys to
provide a direct redshift calibration. Using self-organising maps (SOMs) we
demonstrate that this spectroscopic compilation is sufficiently complete for
KiDS, representing of the effective 2D cosmic shear sample. We use the
SOM to define a represented `gold' cosmic shear sample, per tomographic
bin. Using mock simulations of KiDS and the spectroscopic training set, we
estimate the uncertainty on the SOM redshift calibration, and find that
photometric noise, sample variance, and spectroscopic selection effects
(including redshift and magnitude incompleteness) induce a combined maximal
scatter on the bias of the redshift distribution reconstruction () of
in all tomographic bins. We show
that the SOM calibration is unbiased in the cases of noiseless photometry and
perfectly representative spectroscopic datasets, as expected from theory. The
inclusion of both photometric noise and spectroscopic selection effects in our
mock data introduces a maximal bias of , or at
confidence, once quality flags have been applied to the SOM. The method
presented here represents a significant improvement over the previously adopted
direct redshift calibration implementation for KiDS, owing to its diagnostic
and quality assurance capabilities. The implementation of this method in future
cosmic shear studies will allow better diagnosis, examination, and mitigation
of systematic biases in photometric redshift calibration.Comment: 22 pages, 10 figures, 4 appendices, accepted for publication in A&
Impact of Salinity on the Gastrointestinal Bacterial Community of Theodoxus fluviatilis
Differences in salinity are boundaries that act as barriers for the dispersal of most aquatic organisms. This creates distinctive biota in freshwater and brackish water (mesohaline) environments. To test how saline boundaries influence the diversity and composition of host-associated microbiota, we analyzed the microbiome within the digestive tract of Theodoxus fluviatilis, an organism able to cross the freshwater and mesohaline boundary. Alpha-diversity measures of the microbiome in freshwater and brackish water were not significantly different. However, the composition of the bacterial community within freshwater T. fluviatilis differed significantly compared with mesohaline T. fluviatilis and typical bacteria could be determined for the freshwater and the mesohaline digestive tract microbiome. An artificial increase in salinity surrounding these freshwater snails resulted in a strong change in the bacterial community and typical marine bacteria became more pronounced in the digestive tract microbiome of freshwater T. fluviatilis. However, the composition of the digestive tract microbiome in freshwater snails did not converge to that found within mesohaline snails. Within mesohaline snails, no cardinal change was found after either an increase or decrease in salinity. In all samples, Pseudomonas, Pirellula, Flavobacterium, Limnohabitans, and Acinetobacter were among the most abundant bacteria. These bacterial genera were largely unaffected by changes in environmental conditions. As permanent residents in T. fluviatilis, they may support the digestion of the algal food in the digestive tract. Our results show that freshwater and mesohaline water host-associated microbiomes respond differently to changes in salinity. Therefore, the salinization of coastal freshwater environments due to a rise in sea level can influence the gut microbiome and its functions with currently unknown consequences for, e.g., nutritional physiology of the host
Glucocorticoids suppress Wnt16 expression in osteoblasts in vitro and in vivo
Glucocorticoid-induced osteoporosis is a frequent complication of systemic glucocorticoid (GC) therapy and mainly characterized by suppressed osteoblast activity. Wnt16 derived from osteogenic cells is a key determinant of bone mass. Here, we assessed whether GC suppress bone formation via inhibiting Wnt16 expression. GC treatment with dexamethasone (DEX) decreased Wnt16 mRNA levels in murine bone marrow stromal cells (mBMSCs) time- and dose-dependently. Similarly, Wnt16 expression was also suppressed after DEX treatment in calvarial organ cultures. Consistently, mice receiving GC-containing slow-release prednisolone pellets showed lower skeletal Wnt16 mRNA levels and bone mineral density than placebo-treated mice. The suppression of Wnt16 by GCs was GC-receptor-dependent as co-treatment of mBMSCs with DEX and the GR antagonist RU-486 abrogated the GC-mediated suppression of Wnt16. Likewise, DEX failed to suppress Wnt16 expression in GR knockout-mBMSCs. In addition, Wnt16 mRNA levels were unaltered in bone tissue of GC-treated GR dimerization-defective GRdim mice, suggesting that GCs suppress Wnt16 via direct DNA-binding mechanisms. Consistently, DEX treatment reduced Wnt16 promoter activity in MC3T3-E1 cells. Finally, recombinant Wnt16 restored DEX-induced suppression of bone formation in mouse calvaria. Thus, this study identifies Wnt16 as a novel target of GC action in GC-induced suppression of bone formation
TABSOLARⓇ – a novel approach of thermo-active (solar) building systems based on ultra-high performance concrete (UHPC)
TABSOLARⓇ elements are novel (solar) thermal components made from ultra-high performance concrete (UHPC) which can be used as designable glazed or unglazed façade cladding elements or thermo-active building systems for heating and/or cooling. They are produced with an innovative production technology which is developed in a current research project together with appropriate system concepts. In order to simplify the system design process and visualize possible TABSOLARⓇ façades on site, new software tools are being developed. Finally, a demonstration façade will be installed on a renovated two-family residential building. The ongoing interactive design process of this first use case is an important part of the project and the overall TABSOLARⓇ concept
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