Kooperativer Bibliotheksverbund

Berlin Brandenburg


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  • 1
    Language: English
    In: Vadose Zone Journal, 2015, Vol.14(4), p.0
    Description: Recent advances in wireless sensor technology allow monitoring of soil moisture dynamics with high temporal resolution at varying spatial scales. The objectives of this study were to: (i) develop an efficient strategy for monitoring soil moisture dynamics at the hillslope scale using a wireless sensor network; and (ii) characterize spatial patterns of soil moisture and infer hydrological processes controlling the dynamics of such patterns, using a method of analysis that allows the identification of the relevant hydrological dynamics within large data sets. We combined soil hydrological and pedological expertise with geophysical measurements and methods from digital soil mapping for designing the monitoring setup for a grassland hillslope in the Schafertal catchment, central Germany. Hypothesizing a wet and a dry soil moisture state to be characteristic of the spatial pattern of soil moisture, we described the spatial and temporal evolution of such patterns using a method of analysis based on the Spearman rank correlation coefficient. We described the persistence and switching mechanisms of the two characteristic states, inferring the local properties that control the observed spatial patterns and the hydrological processes driving the transitions. The spatial organization of soil moisture appears to be controlled by different processes in different soil horizons, and the topsoil's moisture does not mirror processes that take place within the soil profile. The results will help to improve conceptual understanding for hydrological model studies at similar or smaller scales and to transfer observation concepts and process understanding to larger or less instrumented areas.
    Keywords: Soils ; Hydrogeology ; Central Europe ; Central Germany ; Characterization ; Diurnal Variations ; Drainage Basins ; Dynamics ; Electromagnetic Induction ; Europe ; Evapotranspiration ; Field Studies ; Gamma-Ray Spectra ; Germany ; Grain Size ; Harz Mountains ; Hydrology ; Latin Hypercube Sampling ; Mechanism ; Moisture ; Monitoring ; Sampling ; Saxony-Anhalt Germany ; Scale Factor ; Schafertal Basin ; Size Distribution ; Slopes ; Soil Profiles ; Soil Surveys ; Soils ; Spatial Distribution ; Spectra ; Surveys ; Tanner ; Temporal Distribution ; Topography ; Unsaturated Zone;
    ISSN: Vadose Zone Journal
    E-ISSN: 1539-1663
    Source: CrossRef
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  • 4
    Language: English
    In: Geoscientific Instrumentation, Methods and Data Systems, 2018, Vol.7(1), pp.83-99
    Description: Sensor-to-sensor variability is a source of error common to all geoscientific instruments that needs to be assessed before comparative and applied research can be performed with multiple sensors. Consistency among sensor systems is especially critical when subtle features of the surrounding terrain are to be identified. Cosmic-ray neutron sensors (CRNSs) are a recent technology used to monitor hectometre-scale environmental water storages, for which a rigorous comparison study of numerous co-located sensors has not yet been performed. In this work, nine stationary CRNS probes of type “CRS1000” were installed in relative proximity on a grass patch surrounded by trees, buildings, and sealed areas. While the dynamics of the neutron count rates were found to be similar, offsets of a few percent from the absolute average neutron count rates were found. Technical adjustments of the individual detection parameters brought all instruments into good agreement. Furthermore, we found a critical integration time of 6 h above which all sensors showed consistent dynamics in the data and their RMSE fell below 1 % of gravimetric water content. The residual differences between the nine signals indicated local effects of the complex urban terrain on the scale of several metres. Mobile CRNS measurements and spatial simulations with the URANOS neutron transport code in the surrounding area (25 ha) have revealed substantial sub-footprint heterogeneity to which CRNS detectors are sensitive despite their large averaging volume. The sealed and constantly dry structures in the footprint furthermore damped the dynamics of the CRNS-derived soil moisture. We developed strategies to correct for the sealed-area effect based on theoretical insights about the spatial sensitivity of the sensor. This procedure not only led to reliable soil moisture estimation during dry-out periods, it further revealed a strong signal of intercepted water that emerged over the sealed surfaces during rain events. The presented arrangement offered a unique opportunity to demonstrate the CRNS performance in complex terrain, and the results indicated great potential for further applications in urban climate research.
    Keywords: Urban Environments ; Monitoring Instruments ; Gravimetry ; Sensors ; Surfaces ; Soil Moisture ; Environmental Monitoring ; Environmental Monitoring ; Water Content ; Water Balance ; Water Balance ; Sensors ; Soil Moisture ; Spatial Discrimination ; Moisture Content ; Instruments ; Offsets ; Research ; Water Balance ; Moisture ; Cosmic Rays ; Urban Areas ; Error Detection ; Water Content ; Detectors ; Dynamics ; Heterogeneity ; Soil Moisture ; Sensors ; Sensors ; Footprints ; Intercomparison ; Soil Dynamics ; Detection ; Soils ; Terrain ; Water Content ; Water Balance;
    ISSN: Geoscientific Instrumentation, Methods and Data Systems
    ISSN: 21930856
    E-ISSN: 2193-0864
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  • 5
  • 6
    Language: English
    In: Environmental Earth Sciences, 2017, Vol.76(1), pp.1-25
    Description: This article provides an overview about the Bode River catchment that was selected as the hydrological observatory and main region for hydro-ecological research within the TERrestrial ENvironmental Observatories Harz/Central German Lowland Observatory. It first provides information about the general characteristics of the catchment including climate, geology, soils, land use, water quality and aquatic ecology, followed by the description of the interdisciplinary research framework and the monitoring concept with the main components of the multi-scale and multi-temporal monitoring infrastructure. It also shows examples of interdisciplinary research projects aiming to advance the understanding of complex hydrological processes under natural and anthropogenic forcings and their interactions in a catchment context. The overview is complemented with research work conducted at a number of intensive research sites, each focusing on a particular functional zone or specific components and processes of the hydro-ecological system.
    Keywords: Monitoring ; Catchment ; Water quality ; Observatory ; Water fluxes
    ISSN: 1866-6280
    E-ISSN: 1866-6299
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  • 7
    Language: English
    In: FEBS Letters, 07 May 2012, Vol.586(9), pp.1363-1369
    Description: ► Biomechanical load of the heart causes ER stress. ► Preload alone does not suffice to cause ER stress. ► Additional elevation in afterload is necessary to induce ER stress. ► The role of afterload could be demonstrated in vitro and in vivo. ► Angiotensin II is only partially responsible for the afterload-induced ER stress. Proteins are folded in the endoplasmic reticulum (ER). ER stress initially leads to compensatory upregulation of ER chaperones and later to apoptosis, but the contribution of biomechanical load vs. neurohumoral stress to myocardial ER stress is unknown. We show that the ER chaperones Grp78 and calreticulin (CRT) are upregulated by afterload, but not by preload in vitro and in vivo. Angiotensin II upregulated ER chaperones in unloaded muscle strips, but the angiotensin receptor-1 antagonist irbesartan did not significantly blunt the induction of ER chaperones by afterload. In monocrotaline-treated rats, Grp78 and CRT were upregulated in the afterloaded right ventricle, but not in the only neurohumorally stressed left ventricle. These findings suggest that afterload but not preload induces myocardial ER stress, largely independent of angiotensin II signaling.
    Keywords: Er Stress ; Preload ; Afterload ; Angiotensin ; Biology ; Chemistry ; Anatomy & Physiology
    ISSN: 0014-5793
    E-ISSN: 1873-3468
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  • 8
    Language: English
    In: Journal of Cellular Physiology, November 2010, Vol.225(2), pp.545-554
    Description: The hepatic‐like phenotype resulting from in vitro differentiation of unrestricted somatic stem cells (USSC) derived from human umbilical cord blood (CB) was analyzed with regard to functional and metabolic aspects. USSC can be differentiated into cells of all three germ layers in vitro and in vivo and, although they share many features with mesenchymal stroma cells (MSC), can be distinguished from these by their expression of DLK1 as well as a restricted adipogenic differentiation potential. For the differentiation procedure described herein, a novel three‐stage differentiation protocol resembling embryonic developmental processes of hepatic endoderm was applied. Hepatic pre‐induction was performed by activinA and FGF4 resulting in enhanced SOX17 and FOXA2 expression. Further differentiation was achieved sequentially by retinoic acid, FGF4, HGF, EGF, and OSM resulting in a hepatic endodermal identity, characterized by the expression of AFP and HNF1α. Thereafter, expression of G6PC, ARG1, FBP1, and HNF4α was observed, thus indicating progressive differentiation. Functional studies concerning albumin secretion, urea formation, and cytochrome‐p450‐3A4 (CYP3A4) enzyme activity confirmed the hepatic‐like phenotype. In order to characterize the differentiated cells at a metabolic level, USSC were incubated with [1‐C]glucose. By tracing the fate of the molecule's label via isotopomer analysis using C NMR spectroscopy, formation of both glycogen and some gluconeogenetic activity could be observed providing evidence of a hepatocyte‐like glucose metabolism in differentiated USSC. In conclusion, the results of the present study indicate that USSC represent a stem cell source with a substantial hepatic differentiation capacity which hold the potential for clinical applications. J. Cell. Physiol. 225: 545–554, 2010. © 2010 Wiley‐Liss, Inc.
    Keywords: Cell Differentiation -- Physiology ; Glucose -- Metabolism ; Hepatocytes -- Cytology ; Stem Cells -- Cytology;
    ISSN: 0021-9541
    E-ISSN: 1097-4652
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  • 9
    In: ASAIO Journal, 2012, Vol.58(3), pp.255-261
    Description: Insufficient liver remnant volume still precludes patients with potentially resectable tumors from curative surgery. Clinically, it has been demonstrated that transplanted adult stem cells promote liver regeneration. However, the mechanisms of the observed functional improvements are unknown. The aim of our study was to evaluate the impact of transplanted human multipotent cord blood-derived unrestricted somatic stem cells (USSC) on liver regeneration and identify the underlying mechanisms in an ovine model. We performed partial embolization of the right liver lobe and grafted USSC in the portal venous system of the left liver lobe. After 4 weeks, livers were explanted and analyzed for differentiation of USSC into hepatocytes by histopathologic examination and for fusion of USSC with recipient hepatocytes by single-cell polymerase chain reaction. The studies revealed that transplanted USSC differentiate into hepatocytes and produce human albumin. No ovine DNA was found in the hepatocytes with a human phenotype. Transplantation of USSC enhances the number of viable hepatocytes in liver disease by differentiation and opens new therapeutic perspectives.
    Keywords: Cord Blood Stem Cell Transplantation ; Liver Regeneration ; Liver Neoplasms, Experimental -- Surgery ; Multipotent Stem Cells -- Transplantation;
    ISSN: 1058-2916
    E-ISSN: 1538943X
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  • 10
    Language: English
    In: Experimental Hematology, 2010, Vol.38(9), pp.809-818.e2
    Description: Generation of induced pluripotent stem (iPS) cells from human cord blood (CB)−derived unrestricted somatic stem cells and evaluation of their molecular signature and differentiation potential in comparison to human embryonic stem cells. Unrestricted somatic stem cells isolated from human CB were reprogrammed to iPS cells using retroviral expression of the transcription factors OCT4, SOX2, KLF4, and C-MYC. The reprogrammed cells were analyzed morphologically, by quantitative reverse transcription polymerase chain reaction, genome-wide microRNA and methylation profiling, and gene expression microarrays, as well as in their pluripotency potential by in vivo teratoma formation in severe combined immunodeficient mice and in vitro differentiation. CB iPS cells are very similar to human embryonic stem cells morphologically, at their molecular signature, and in their differentiation potential. Human CB-derived unrestricted somatic stem cells offer an attractive source of cells for generation of iPS cells. Our findings open novel perspectives to generate human leukocyte antigen−matched pluripotent stem cell banks based on existing CB banks. Besides the obvious relevance of a second-generation CB iPS cell bank for pharmacological and toxicological testing, its application for autologous or allogenic regenerative cell transplantation appears feasible.
    Keywords: Medicine
    ISSN: 0301-472X
    E-ISSN: 1873-2399
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