julilili42/papers huggingface dataset:
The adrenaline‐induced colonic K + secretion is conducted by the ZERO splice variant of K Ca 1.1 (BK)
2009-04-01

Colonic K + secretion in mammals under go long term hormonal‐ and short term regulation by local agonists. The BK channel has previously been identified as the only luminal K + channel in resting, Ca 2+ ‐activated and aldosterone‐induced distal K + secretion. Agonists elevating cAMP are potent activators of colonic K + secretion. The K + channel responsible for cAMP‐induced K + secretion remains to be identified. In this study we used Ussing chambers to identify adrenalin‐induced electrogenic K + secretion. In mouse colon we found that adrenaline‐induced ion secretion is a compound effect of a dominating anion secretion and a smaller electrically opposing K + secretion. Using tissue from either BK or CFTR KO and WT mice we were able to isolate the adrenaline‐induced K + secretion. We found that adrenaline‐induced K + secretion: 1) is absent in BK −/− tissue, 2) is up‐regulated in mice on a high K + diet and 3) is present as sustained positive current in colon from CFTR −/− mice. We also identified that colonic enterocytes express STREX and ZERO C‐terminal BK α‐subunit splice variants. Importantly, the ZERO variant known to be activated by cAMP is differentially up‐regulated in animals on high K + diet. In summary, these results strongly indicate that the adrenalin‐induced distal colonic K + secretion is mediated by the BK channel and likely involves aldosterone‐induced ZERO splice variant up‐regulation.
Cytomegalovirus (CMV) and human longevity: lessons from long-lived families (82.5)
2009-04-01

Abstract Seropositivity for Cytomegalovirus (CMV) is one of the parameters comprising the "immune risk profile" (IRP) predicting mortality in the very elderly. However, as many centenarians are CMV-seropositive (CMV+), not infection per se, but the way in which the immune system controls the virus, might be important in ensuring longevity. To analyze this, we have investigated the CMV prevalence of individuals with 30% decreased mortality risk from long-lived families (offspring, n=200) and their partners as controls (n=200). 10-colour flow cytometry was used to determine the frequency of different adaptive and innate immune subsets in 100 offspring and 100 partners. CMV-seroprevalence was significantly less frequent in offspring, despite many sharing their daily living with an infected partner. The expected highly significant age-associated decrease in naïve T-cells and accumulation of late-differentiated memory T-cells in CMV+ individuals was confirmed only in controls whereas CMV+ and CMV-negative offspring showed similar immune profiles. Our data suggest that individuals genetically enriched for longevity are more resistant to becoming infected with CMV. Furthermore, even when they are infected, they seem to be less susceptible to CMV-driven changes to the immune system. We feel that these phenomena are likely to be related, perhaps causally. This work was supported by EU 7FP LifeSpan (LSHG-CT-2007-036894), DFG-SFB685-B4 and DFG-PA 361-11/1
Collapse structures and the segregation and accumulation of melt
2009-04-01

Although large volumes of magma and fluid move through the crust, the sites where these volumes once resided are difficult to recognize. We show that some (foliation) boudinage and shear band structures, which are classically interpreted as resulting from externally imposed extension or shearing, are better explained by the ductile collapse of magmaor fluid-filled voids (Bons et al. 2008). Experiments show that the shape of the collapse structures depends on the original shape of the void and the direction of confluence of its walls when its contents are drained. This can lead to both symmetrical boudin-like, and asymmetrical, shear band-like structures. The recognition of the true nature of these structures necessitates a re-evaluation of strain measurements reported in the literature and the tectonic models based on them. Identifying the “missing volumes” clarifies the process of segregation and accumulation of melt as it ascends through the crust to make many cubic kilometer-sized granitoid plutons in the upper crust.
Sustainable Management of Urban Heat Islands
2009-04-01

Previous studies focus on spatial temperature trends in the subsurface, and only a few have been able to reveal temporal trends, for which long-term measurement records are needed. This study is dedicated to two German locations: the city of Frankfurt/Main and the city of Cologne. The purpose of the study in Frankfurt is a comprehensive field investigation of the spatial temperature variations in the underlying aquifers, while in Cologne the attention is also on the temporal trends of urban groundwater temperatures. Of particular interest is not only to develop a sustainable management concept, but also a quantitative geophysical and hydrogeological assessment. For the city of Frankfurt/Main, the Hessian Agency for the Environment and Geology (HLUG) provides access to ongoing, highly spatially resolved field measurement locations. For Cologne, about 40 years old intensive temperature records will be utilized and compared to the status-quo. Furthermore, major geothermal projects in both cities will be reported and quantitatively analyzed in order to study the urban anthropogenic impacts. For this, heat transport models will be set up for at least one city. In site-specific integrative management strategies a balance between heat extraction and injection is elaborated. Finally, the findings of these case studies will be translated into a general guidance for those other urban areas with substantial heat anomalies that exist worldwide.
Hydrothermal Oxidation of Silicon Carbide and Its Bearing on Wet Wear Mechanisms
2009-04-01

Static hydrothermal oxidation experiments in a diamond anvil apparatus using wafer-quality single-crystal silicon carbide and observations from transmission electron microscopy from tribolgical tests on sintered silicon carbide are combined to gain insight into the wear process in water. The evidence points to an active type of oxidation under hydrothermal conditions, i.e. there are no primary condensed reaction products. The formed tribolayer is topographically highly variable and consists of dissambled silicon carbide (μm to nm-scaled), which contains secondary, precipitated silica in cracks and voids or as a glue in areas between original asperities. Hydrothermal pressures of several hundred MPa seem feasible and are seen as responsible both for fatigue and surface roughening as well as the formation of the smooth main wear track, which reduces friction favourably.
Mapping of geomorphic processes on abandoned fields and cultivated land in small catchments in semi-arid Spain
2009-04-01

In semi-arid landscapes vegetation succession on abandoned agricultural land is a long lasting process due to the water deficit for the best time of the year. During this phase of succession, geomorphic processes like the formation and development of rills, gullies and other geomorphic processes lead to a more or less constant deterioration of the abandoned land. But also on currently cultivated land and under quasi-natural vegetation the processes of soil degradation by flowing water take place. Regarding small catchments like gully catchments, the topography and the land cover (abandoned land, cultivated land, quasi-natural vegetation) are highly important factors in gully formation and soil degradation. Another important point is the distribution of different land cover units and therefore the connectivity of the catchment as described by Bracken & Croke (2007). In this study, 11 catchments of single gullies have been mapped geomorphologically and compared to the rate of gully development derived from small-format aerial photography. It could be shown that there is a high variability of processes due to differences in topography and the way the land is or has been cultivated. On abandoned land, geomorphic processes are highly active and enhance or even predestinate the direction of headcut movement. Another result is that geomorphological mapping of these gully catchments revealed interactions and dependencies of linear erosion features like the connection to the main drainage line, e.g. the gully. In the larger of the observed catchments (>5 ha) it became clear that some catchments have morphological features that tend to enhance connectivity (long rills, shallow drainage lines) and some catchments have features which tend to restrict connectivity (terraces, dense vegetation). In “more connected” catchments the retreat rate of the headcut is generally higher. By the method of geomorphological mapping, valuable information about the soil degrading processes taking place in gully catchments and especially on abandoned lands could be derived.
Three-Gorges-Dam: Studying the ecological impacts in a highly dynamic ecosystem
2009-04-01

(1) University of Tuebingen, Geographical Institute, Department of Geomorphology and Soil Science, Tubingen, Germany (thomas.scholten@uni-tuebingen.de), (2) University of Potsdam, Department of Geosciences, Potsdam, Germany, (3) Giessen University, Department of Geography, Giessen, Germany, (4) University of Erlangen-Nuremberg (Germany), Department of Applied Geology, Erlangen, Germany, (5) Research Centre Juelich, Institute of Chemistry and Dynamics of the Geosphere, Julich, Germany, (6) University of Geosciences, Department of Geotechnical Engineering and Engineering Geology, Wuhan, P. R. China
Assessing phonetic talent in second language performance: The relationship between perception abilities in the native and the second language and production.
2009-04-01

An extensive project that aims to assess innate phonetic talent is introduced. It investigates language performance of 103 native speakers of German in their native language, in English and (to a limited degree) in Hindi. The project’s original priority is to establish a talent score that serves as the basis for a neurolinguistic study which attempts to find correlates between phonetic talent and brain anatomy/function. For this purpose tasks investigating neurobiological, psychological, and other factors influencing performance are also conducted. Innate talent is to be distinguished from superficial proficiency by limiting or eliminating the influence of interfering factors such as language experience. The test subjects are investigated with respect to different manifestations of their production (e.g., quasi-spontaneous speech, reading), perception (e.g., discrimination, identification), and imitation abilities in both German and English. A first analysis of the interactions between all perception and production scores shows a significant correlation at the level of p &amp;lt; 0.05. The correlation is especially high (p &amp;lt; 0.01) between perception tasks involving the interpretation of intonational features of both English and German and production abilities (again both in German and English), suggesting a certain cross-language predictive power.
NKG2D-mediated activation of NK cells by allogeneic CD34+ blood cells. (141.9)
2009-04-01

Abstract Background: We have previously demonstrated that human CD34+ cells and allogeneic T lymphocytes cross-interact in-vitro. In this study, we addressed the interaction bewteen CD34+ cells and allogeneic NK cells. Methods: Purified CD3-CD56+ NK cells were cultured with allogeneic CD34+ or CD14+ blood cells or with 1000 U/ml IL-2. NK cells were then used to lyse NK-sensitive K562 (NK activity) or NK-resistant Daudi cells (LAK activity) in a 51Cr release assay. Results: CD34+ cells induced greater NK activity than monocytes (p=0.02). While LAK activity was negligible before culture, it increased upon culture with CD34+ cells, but not monocytes (p=0.01). Activation of NK cells by CD34+ cells was comparable to high dose IL-2. NK cell activation was also documented by CD69 and CD25 in NK cells and by production of IFN? and TNF?. CD34+-induced NK activation was inhibited by anti-NKG2D antibody. However, anti-NKG2D antibody did not prevent NK activation by IL-2. Moreover, surface expression of NKG2D on NK cells was downregulated by CD34+ cells but not IL-2. Expression of NKG2D ligands (MICA-B and ULBP1-3) is currently being tested in CD34+ cells. Finally, NK cells affected the phenotype of CD34+ cells, that upregulated their expression of CD40 and CD86. Conclusions: Our study suggest a cross talk between NK cells and allogeneic CD34+ cells through a NKG2D-related mechanism.
The lectin‐like domain of TNF blunts LLO‐mediated suppression of SGK1 activity and hyperpermeability in human airway H441 cells
2009-04-01

Listeriosis can result in lethal pulmonary permeability edema, with reduced sodium uptake capacity and epithelial/endothelial hyperpermeability. This study investigated the effect of L. monocytogenes' main virulence factor, Listeriolysin O (LLO), on the serum and glucocorticoid dependent kinase 1 (SGK1) and on prostasin, both positive regulators of epithelial sodium channel (ENaC) expression. Moreover, the effects of the TNF‐derived TIP peptide, mimicking its lectin‐like domain, on SGK1 and prostasin expression and permeability in LLO‐treated human H441 cells were investigated. This peptide reduces edema formation in murine models. LLO significantly reduced T256 phosphorylation, required for full activation of SGK1, blunted prostasin expression and reduced expression of the crucial ENaC alpha subunit (Western Blotting). The toxin dose‐dependently induced hyperpermeability in H441 monolayers, as assessed in Electrical Cell Substrate Impedance Sensing. The TIP peptide significantly inhibited hyperpermeability and restored SGK1 activity at 24h in LLO‐treated H441 cells. LLO is thus implicated in permeability edema formation by reducing ENaC expression and epithelial barrier integrity. The TNF‐derived TIP peptide can counteract these effects, indicating its therapeutic potential for the treatment of listeriosis‐related permeability edema.
Pharmacologic evidence for stabilization of a nucleotide‐bound, stimulatory conformation of SUR1Q1178R, an ABCC8 neonatal diabetes mutation
2009-04-01

Mutations in ABCC8/SUR1 that generate hyperactive neuroendocrine‐type Kir6.2/SUR1 K ATP channels are a cause of neonatal diabetes. Analysis of one mutant, SUR1 Q1178R , is consistent with the MgATP‐dependent accumulation of a post‐hydrolytic, ADP‐bound enzymatic intermediate that stimulates channel opening. SUR1 is the target for K ATP channel inhibitors, e.g., glibenclamide, and openers, e.g., diazoxide and NCC. In the Kir6.2/SUR1 channel, the mutation potentiated the negative allosteric effect of MgATP on binding of [ 3 H]‐glibenclamide reducing the number of specific channel binding sites by ~50% whereas in wild‐type, the K D increased 4.5x. This is consistent with a greater depopulation of antagonist binding sites in the R1178 channels at steady‐state. MgATP is required for opener function and high‐affinity agonist binding. SUR1 R1178 increased the apparent number of agonist binding sites, without affecting their K i , implying these agonists interact with the stimulatory, post‐hydrolytic conformation stabilized by the R1178 substitution. The data suggest the stimulatory, post‐hydrolytic conformation could accumulate either because R1178 increases the rate of ATP hydrolysis or reduces the rate of product dissociation, and rationalize the need for a higher glibenclamide dose to reach metabolic control in ABCC8 neonatal diabetes patients. Supported by NIH DK44311(JB); DFG QU_100/4‐1(UQ).
Pedogenesis and soil moisture, but not soil temperature best explain large-scale patterns of soil carbon and soil nitrogen contents in the permafrost ecosystems of Tibetan alpine grasslands
2009-04-01

The Tibetan Plateau is an essential area to study potential feedback effects of soils to climate change due to the rapid rise of air temperature in the past several decades as well as the large amounts of organic carbon (Corg) stored in soils, particularly in permafrost-affected areas. In order to predict the impact of environmental change on ecosystem functioning, it is of great importance to understand how Corg and soil nitrogen (N) stocks are controlled under changing climate conditions in extreme environments. We therefore investigated the main parameters influencing Corg and N at 47 sites along a 1,200 km transect across the high-altitude and low-latitude permafrost region of the central-eastern Tibetan Plateau. Sites with continuous or discontinuous permafrost as well as areas without or heavily degraded permafrost were studied for comparison of soil dynamics under various environmental settings. Due to the high number of samples and the large-scale transect concept, sophisticated statistical analyses showing significant relationships between pedological parameters as well as Corg and N contents were carried out.
Interpolation of Steady-State Concentration Data by Inverse Modeling
2009-04-01

In most groundwater applications, measurements of concentration are limited in number and sparsely distributed within the domain of interest. Therefore, interpolation techniques are needed to obtain most likely values of concentration at locations where no measurements are available. For further processing, for example, in environmental risk analysis, interpolated values should be given with uncertainty bounds, so that a geostatistical framework is preferable. Linear interpolation of steady-state concentration measurements is problematic because the dependence of concentration on the primary uncertain material property, the hydraulic conductivity field, is highly nonlinear, suggesting that the statistical interrelationship between concentration values at different points is also nonlinear. We suggest interpolating steady-state concentration measurements by conditioning an ensemble of the underlying log-conductivity field on the available hydrological data in a conditional Monte Carlo approach. Flow and transport simulations for each conditional conductivity field must meet the measurements within their given uncertainty. The ensemble of transport simulations based on the conditional log-conductivity fields yields conditional statistical distributions of concentration at points between observation points. This method implicitly meets physical bounds of concentration values and non-Gaussianity of their statistical distributions and obeys the nonlinearity of the underlying processes. We validate our method by artificial test cases and compare the results to kriging estimates assuming different conditional statistical distributions of concentration. Assuming a beta distribution in kriging leads to estimates of concentration with zero probability of concentrations below zero or above the maximal possible value; however, the concentrations are not forced to meet the advection-dispersion equation.
A Tale of Two Viscosities
2009-04-01

Abstract We describe a series of 12 large-strain, two-dimensional simple shear numerical experiments on two-phase linear and non-linear viscous materials. The modal percentage of the two-phases, their relative viscosities and the stress exponent of the dependence of viscosity on stress were systematically varied, allowing us to observe the effects of these parameters on the flow behaviour of the system. All experiments exhibited localisation, but the extent and type of localisation varied considerably, and the range of parameters allows both classical SC as well as SC′ structures to form. The inter-granular finite strain geometries also varied systematically, although there is a tradeoff between non-linearity of viscosity and the viscosity contrast that results in similar geometries for quite different mechanical behaviour. The finite rotation of the harder phases was similar within any one experiment. Originally parallel passive marker lines thus remain sub-parallel after deformation and rotation, which may be mistaken for non-rotation. The internal deformability and interaction between grains allows meta-stable grain elongation orientations to form, without any additional consideration of external slip surfaces. The slight variability of initial grain geometry and subsequent grain interactions leads to a wide variability in final grain shapes, for the same initial viscosities.
Macrophage phagocytosis and lysozyme-based digestion of peptidoglycan are required for IL-1β production in response to S. aureus (134.38)
2009-04-01

Abstract IL-1β produced by phagocytes is important for protection against Staphylococcus aureus, a bacterium that causes serious skin and invasive diseases and is contributing to a current public health crisis due to the emergence of methicillin-resistant strains. Secretion of IL-1β requires both activation of a transcriptional signal to stimulate production of pro- IL-1β, (usually provided by TLR signaling) and a second signal to stimulate processing by inflammasome complexes and release of the mature cytokine. We show here that phagocytosis and lysozyme-based degradation of bacterial cell walls are functionally coupled to activation of Nalp3 inflammasomes and secretion of IL-1β in response to live S. aureus and to S. aureus peptidoglycan. Further, a S. aureus peptidoglycan-modifying enzyme that makes its peptidoglycan resistant to lysozyme strongly suppresses inflammasome activation. This is the first demonstration of a case whereby a bacterium avoids IL-1β secretion through chemical modification of its cell wall peptidoglycan, and we hypothesize that this reduced IL-1β production is key to successful mucosal colonization and infection. This research is supported by grants from NIGMS and the American Heart Association.
Extensive expression regulation and lack of heterologous enzymatic activity of the Class II trehalose metabolism proteins from Arabidopsis thaliana
2009-04-02

ABSTRACT Trehalose metabolism has profound effects on plant growth and metabolism, but the mechanisms involved are unclear. In Arabidopsis , 21 putative trehalose biosynthesis genes are classified in three subfamilies based on their similarity with yeast TPS1 (encoding a trehalose‐6‐phosphate synthase, TPS) or TPS2 (encoding a trehalose‐6‐phosphate phosphatase, TPP). Although TPS1 (Class I) and TPPA and TPPB (Class III) proteins have established TPS and TPP activity, respectively, the function of the Class II proteins (AtTPS5‐AtTPS11) remains elusive. A complete set of promoter‐ β ‐glucurinidase/green fluorescent protein reporters demonstrates their remarkably differential tissue‐specific expression and responsiveness to carbon availability and hormones. Heterologous expression in yeast furthermore suggests that none of the encoded enzymes displays significant TPS or TPP activity, consistent with a regulatory rather than metabolic function for this remarkable class of proteins.