julilili42/papers huggingface dataset:
Soil Environmental Conditions and Microbial Build-Up Mediate the Effect of Plant Diversity on Soil Nitrifying and Denitrifying Enzyme Activities in Temperate Grasslands
2013-04-17

Random reductions in plant diversity can affect ecosystem functioning, but it is still unclear which components of plant diversity (species number - namely richness, presence of particular plant functional groups, or particular combinations of these) and associated biotic and abiotic drivers explain the observed relationships, particularly for soil processes. We assembled grassland communities including 1 to 16 plant species with a factorial separation of the effects of richness and functional group composition to analyze how plant diversity components influence soil nitrifying and denitrifying enzyme activities (NEA and DEA, respectively), the abundance of nitrifiers (bacterial and archaeal amoA gene number) and denitrifiers (nirK, nirS and nosZ gene number), and key soil environmental conditions. Plant diversity effects were largely due to differences in functional group composition between communities of identical richness (number of sown species), though richness also had an effect per se. NEA was positively related to the percentage of legumes in terms of sown species number, the additional effect of richness at any given legume percentage being negative. DEA was higher in plots with legumes, decreased with increasing percentage of grasses, and increased with richness. No correlation was observed between DEA and denitrifier abundance. NEA increased with the abundance of ammonia oxidizing bacteria. The effect of richness on NEA was entirely due to the build-up of nitrifying organisms, while legume effect was partly linked to modified ammonium availability and nitrifier abundance. Richness effect on DEA was entirely due to changes in soil moisture, while the effects of legumes and grasses were partly due to modified nitrate availability, which influenced the specific activity of denitrifiers. These results suggest that plant diversity-induced changes in microbial specific activity are important for facultative activities such as denitrification, whereas changes in microbial abundance play a major role for non-facultative activities such as nitrification.
Controlled cobalt doping in biogenic magnetite nanoparticles
2013-04-17

Cobalt-doped magnetite (Co x Fe 3 − x O 4 ) nanoparticles have been produced through the microbial reduction of cobalt–iron oxyhydroxide by the bacterium Geobacter sulfurreducens . The materials produced, as measured by superconducting quantum interference device magnetometry, X-ray magnetic circular dichroism, Mössbauer spectroscopy, etc., show dramatic increases in coercivity with increasing cobalt content without a major decrease in overall saturation magnetization. Structural and magnetization analyses reveal a reduction in particle size to less than 4 nm at the highest Co content, combined with an increase in the effective anisotropy of the magnetic nanoparticles. The potential use of these biogenic nanoparticles in aqueous suspensions for magnetic hyperthermia applications is demonstrated. Further analysis of the distribution of cations within the ferrite spinel indicates that the cobalt is predominantly incorporated in octahedral coordination, achieved by the substitution of Fe 2+ site with Co 2+ , with up to 17 per cent Co substituted into tetrahedral sites.
TAX COMPETITION IN A SIMPLE MODEL WITH HETEROGENEOUS FIRMS: HOW LARGER MARKETS REDUCE PROFIT TAXES*
2013-04-17

We set up a simple two‐country model of tax competition where firms with different productivity decide in which location to produce and sell output. In this model, a unique, asymmetric Nash equilibrium is shown to exist, provided that countries are sufficiently different with respect to their exogenous market size. Sorting of firms occurs in equilibrium, as the smaller country levies the lower tax rate and attracts the low‐cost firms. A simultaneous expansion of both markets that raises the profitability of firms intensifies tax competition and causes both countries to reduce their tax rates, despite higher corporate tax bases.
The burgers’ paradox: Migration and the transnationalization of social inequality in southern Ghana
2013-04-17

Based on an ethnographic case study conducted in the Dormaa District, this article describes a group which has emerged in southern Ghana in the last decades and is called Burgers. Burgers are transnational migrants who have materially achieved a middle-class status in their country of origin by doing blue-collar jobs in Western Europe or North America. Their emergence as a class highlights the links between transnational migration, global inequalities and national imaginaries of social status. Since their relative wealth lacks conventional legitimations, these migrants are a cause of irritation to existing imaginaries of social status in Ghana. In this context, redistribution of resources and collaborative silences are central to understanding how Burgers negotiate their status and convert money into symbolic capital.
WHY FOREIGN OWNERSHIP MAY BE GOOD FOR YOU*
2013-04-17

We develop a two‐country model with heterogeneous producers and rent‐sharing at the firm level. We identify two sources of a multinational wage premium: A composition effect because multinational firms are more productive, make higher profits, and pay higher wages, and a firm‐level wage effect, because a firm makes higher global profits and thus pays higher wages in its home market when becoming multinational. With two identical countries, the wage premium is fully explained by firm characteristics. Allowing for technology differences between countries, a residual wage premium exists in the technologically backward country but not in the advanced country.
Circulating platelet-progenitor cell coaggregate formation is increased in patients with acute coronary syndromes and augments recruitment of CD34+ cells in the ischaemic microcirculation
2013-04-17

These findings imply that circulating platelet/CD34+ cell coaggregate levels are increased in ACS, especially in STEMI, which may be a novel mechanism of domiciliation of CD34+ progenitor cells to the injured microvasculature after acute myocardial infarction.
The discovery of oligodendroglia cells by Rio-Hortega: his original articles. 1921.
2013-04-17

Comment on: del Río-Hortega P. Glia with very few processes (oligodendroglia). Clin Neuropathol. 2012; 31: 440-459, originally published in Archivos de Neurobiología. 1921; 2: 16-43 and del Río-Hortega P. Are the glia with very few processes homologous with Schwann cells? Clin Neuropathol. 2012; 31: 460-462, originally published in Bol de la Soc Esp de Biol. 1922; X: 25-28.
Multisensoral remote sensing based modelling of the water balance of endorheic lakes on the Tibetan Plateau
2013-04-17

The water balance of endorheic lakes on the Tibetan Plateau plays an important role in the assessment of hydrological system dynamics such as glacier retreat or changing patterns of monsoonal precipitation in relation to global warming effects. Since those lakes are remote and hard to access, multisensoral remote sensing seems to be a valuable tool to generate hydrological relevant information as modelling input (land cover, trends in mountain lake ice cover, etc.) or validation base (lake level changes). Integrative methodological approaches linking state-of-the-art remote sensing with distributed hydrological modelling are the only way to quantify the water balance and to provide a forecast of the future water availability on the Tibetan Plateau.
Monocytes/macrophages support mammary tumor invasivity by co-secreting lineage-specific EGFR ligands and a STAT3 activator
2013-04-18

Abstract Background Tumor-associated macrophages (TAM) promote malignant progression, yet the repertoire of oncogenic factors secreted by TAM has not been clearly defined. We sought to analyze which EGFR- and STAT3-activating factors are secreted by monocytes/macrophages exposed to tumor cell-secreted factors. Methods Following exposure of primary human monocytes and macrophages to supernatants of a variety of tumor cell lines, we have analyzed transcript and secreted protein levels of EGFR family ligands and of STAT3 activators. To validate our findings, we have analyzed TAM infiltration levels, systemic and local protein levels as well as clinical data of primary breast cancer patients. Results Primary human monocytes and macrophages respond to tumor cell-derived factors by secreting EGFR- and STAT3-activating ligands, thus inducing two important oncogenic pathways in carcinoma cells. Tumor cell-secreted factors trigger two stereotype secretory profiles in peripheral blood monocytes and differentiated macrophages: monocytes secrete epiregulin (EREG) and oncostatin-M (OSM), while macrophages secrete heparin-binding EGF-like growth factor (HB-EGF) and OSM. HB-EGF and OSM cooperatively induce tumor cell chemotaxis. HB-EGF and OSM are co-expressed by TAM in breast carcinoma patients, and plasma levels of both ligands correlate strongly. Elevated HB-EGF levels accompany TAM infiltration, tumor growth and dissemination in patients with invasive disease. Conclusions Our work identifies systemic markers for TAM involvement in cancer progression, with the potential to be developed into molecular targets in cancer therapy.
Towards new paradigms: multiple pathways for the Arabian Neolithic
2013-04-18

The origin and course of the Neolithic on the Arabian Peninsula is the subject of an ongoing academic debate. Faunal data suggest an origin for domestication of animals in the Levant and these can be found in Arabia from the sixth millennium onwards. In contrast, lithic evidence does not support the hypothesis that Neolithic herders, accompanying their herds, spread over the entire Peninsula, as they did not leave significant traces of their material culture. Although Pre‐Pottery Neolithic A ( PPNA )/ PPNB influences can be traced across the northern part of Arabia, it is barely possible to observe them further south. By contrast, lithic technology in this region is characterised by major indigenous developments that might originate from a Pleistocene cultural heritage. By discussing the process of Neolithisation in Arabia from different points of view we can avoid the pitfalls of simplistic or monocausal models as well as preconceptions. Furthermore, we will be able to demonstrate that the Neolithic developed differently in different regions of the Arabian Peninsula.
Altered regulation of cytosolic Ca2+ concentration in dendritic cells from klotho hypomorphic mice
2013-04-18

The function of dendritic cells (DCs), antigen-presenting cells regulating naïve T-cells, is regulated by cytosolic Ca 2+ concentration ([Ca 2+ ] i ). [Ca 2+ ] i is increased by store-operated Ca 2+ entry and decreased by K + -independent (NCX) and K + -dependent (NCKX) Na + /Ca 2+ exchangers. NCKX exchangers are stimulated by immunosuppressive 1,25-dihydroxyvitamin D3 [1,25(OH) 2 D 3 ], the biologically active form of vitamin D. Formation of 1,25(OH) 2 D 3 is inhibited by the antiaging protein Klotho. Thus 1,25(OH) 2 D 3 plasma levels are excessive in Klotho-deficient mice ( klotho hm ). The present study explored whether Klotho deficiency modifies [Ca 2+ ] i regulation in DCs. DCs were isolated from the bone marrow of klotho hm mice and wild-type mice ( klotho +/+ ) and cultured for 7–9 days with granulocyte-macrophage colony-stimulating factor. According to major histocompatibility complex II (MHC II) and CD86 expression, differentiation and lipopolysaccharide (LPS)-induced maturation were similar in klotho hm DCs and klotho +/+ DCs. However, NCKX1 membrane abundance and NCX/NCKX-activity were significantly enhanced in klotho hm DCs. The [Ca 2+ ] i increase upon acute application of LPS (1 μg/ml) was significantly lower in klotho hm DCs than in klotho +/+ DCs, a difference reversed by the NCKX blocker 3′,4′-dichlorobenzamyl (DBZ; 10 μM). CCL21-dependent migration was significantly less in klotho hm DCs than in klotho +/+ DCs but could be restored by DBZ. NCKX activity was enhanced by pretreatment of klotho +/+ DC precursors with 1,25(OH) 2 D 3 the first 2 days after isolation from bone marrow. Feeding klotho hm mice a vitamin D-deficient diet decreased NCKX activity, augmented LPS-induced increase of [Ca 2+ ] i , and enhanced migration of klotho hm DCs, thus dissipating the differences between klotho hm DCs and klotho +/+ DCs. In conclusion, Klotho deficiency upregulates NCKX1 membrane abundance and Na + /Ca 2+ -exchange activity, thus blunting the increase of [Ca 2+ ] i following LPS exposure and CCL21-mediated migration. The effects are in large part due to excessive 1,25(OH) 2 D 3 formation.
Ring opening of 2-aza-3-borabicyclo[2.2.0]hex-5-ene, the Dewar form of 1,2-dihydro-1,2-azaborine: stepwise versus concerted mechanisms
2013-04-18

The ring opening of the Dewar form of 1,2-dihydro-1,2-azaborine, 2-aza-3-borabicyclo[2.2.0]hex-5-ene ( 3 ) is investigated by theoretical methods by using multiconfiguration SCF (CASSCF) and coupled cluster theory [CCSD(T)] with basis sets up to polarised quadruple-zeta quality. The title compound was previously reported to form photochemically in cryogenic noble gas matrices from 1,2-dihydro-1,2-azaborine ( 4 ). Four reaction paths for the thermal ring opening of 3 to 4 could be identified. These are the conventional disrotatory and conrotatory electrocyclic ring-opening pathways where the BN unit is only a bystander. Two more favourable paths are stepwise and involve 1,3-boron–carbon interactions. The lowest energy barrier for the isomerisation reaction, 22 kcal mol −1 , should be high enough for an experimental observation in solution. However, in solution the dimerisation of 3 is computed to have a very low barrier (3 kcal mol −1 ), and thus 3 is expected to be a short-lived reactive intermediate.
Isotopically modified Ge detectors for GERDA: from production to operation
2013-04-18

ABSTRACT: The GERDA experiment searches for the neutrinoless double beta (0νββ) decay of 76Ge using high-purity germanium detectors made of material enriched in 76Ge. For Phase II of the experiment a sensitivity for the half life T 0ν1/2 ∼ 2 · 1026 yr is envisioned. Modified Broad En-ergy Germanium detectors (BEGe) with thick n+ electrodes provide the capability to efficiently identify and reject background events, while keeping a large acceptance for the 0νββ-decay signal through novel pulse-shape discrimination (PSD) techniques. The viability of producing thick-window BEGe-type detectors for the GERDA experiment is demonstrated by testing all the produc-tion steps from the procurement of isotopically modified germanium up to working BEGe detectors. Comprehensive testing of the spectroscopic as well as PSD performance of the GERDA Phase II prototype BEGe detectors proved that the properties of these detectors are identical to those pro-duced previously from natural germanium material following the standard production line of the manufacturer. Furthermore, the production of BEGe detectors from a limited amount of isotopically modified
Klotho sensitivity of the hERG channel
2013-04-18

Klotho, a hormone and enzyme, is a powerful regulator of ageing and life span. Klotho deficiency leads to cardiac arrythmia and sudden cardiac death. We thus explored whether klotho modifies cardiac K + ‐channel hERG. Current was determined utilizing dual electrode voltage clamp and hERG protein abundance utilizing immunohistochemistry and chemiluminescence in Xenopus oocytes expressing hERG with or without klotho. Coexpression of klotho increased cell membrane hERG‐protein abundance and hERG current at any given voltage without significantly modifying the voltage required to activate the channel. The effect of klotho coexpression was mimicked by recombinant klotho protein and reversed by β‐glucuronidase‐inhibitor d ‐saccharic acid‐1,4‐lactone.
Faculty Opinions recommendation of The antinociceptive effect of intrathecal administration of glycine transporter-2 inhibitor ALX1393 in a rat acute pain model.
2013-04-18

BACKGROUND: Glycinergic neurons in the spinal dorsal horn have been implicated in the inhibition of spinal pain processing in peripheral inflammation and chronic pain states. Neuronal isoform glycine transporter-2 (GlyT2) reuptakes presynaptically released glycine and regulates the glycinergic neurotransmission. In this study, we examined whether a selective GlyT2 inhibitor, ALX1393, elicits an antinociceptive effect in a rat acute pain model.METHODS: Male Sprague-Dawley rats were implanted with a catheter intrathecally. The effects of intrathecal administration of ALX1393 (4, 20, or 40 microg) on thermal, mechanical, and chemical nociception were evaluated by tail flick, hot plate, paw pressure, and formalin tests. Furthermore, to explore whether ALX1393 affects motor function, a rotarod test was performed.RESULTS: ALX1393 exhibited antinociceptive effects on the thermal and mechanical stimulations in a dose-dependent manner. The maximal effect of ALX1393 was observed at 15 min after administration, and a significant effect lasted for about 60 min. These antinociceptive effects were reversed completely by strychnine injected immediately after the administration of ALX1393. In the formalin test, ALX1393 inhibited pain behaviors in a dose-dependent manner, both in the early and late phases, although the influence was greater in the late phase. In contrast to antinociceptive action, ALX1393 did not affect motor function up to 40 microg.CONCLUSIONS: This study demonstrates the antinociceptive action of ALX1393 on acute pain. These findings suggest that the inhibitory neurotransmitter transporters are promising targets for the treatment of acute pain and that the selective inhibitor of GlyT2 could be a novel therapeutic drug. PMID: 20081141
Carmustine-Induced Phosphatidylserine Translocation in the Erythrocyte Membrane
2013-04-19

The nitrosourea alkylating agent, carmustine, is used as chemotherapeutic drug in several malignancies. The substance triggers tumor cell apoptosis. Side effects of carmustine include myelotoxicity with anemia. At least in theory, anemia could partly be due to stimulation of eryptosis, the suicidal death of erythrocytes, characterized by cell shrinkage and breakdown of phosphatidylserine asymmetry of the cell membrane with phosphatidylserine exposure at the erythrocyte surface. Stimulators of eryptosis include increase of cytosolic Ca2+ activity ([Ca2+]i). The present study tested whether carmustine triggers eryptosis. To this end [Ca2+]i was estimated from Fluo3 fluorescence, cell volume from forward scatter, phosphatidylserine exposure from annexin V binding, and hemolysis from hemoglobin release. As a result a 48 h exposure to carmustine (≥25 μM) significantly increased [Ca2+]i, decreased forward scatter and increased annexin V binding. The effect on annexin V binding was significantly blunted in the absence of extracellular Ca2+. In conclusion, carmustine stimulates eryptosis at least partially by increasing cytosolic Ca2+ activity.
Children Value Informativity Over Logic in Word Learning
2013-04-22

The question of how children learn the meanings of words has long puzzled philosophers and psychologists. As Quine famously pointed out, simply hearing a word in context reveals next to nothing about its meaning. How then do children learn to understand and use words correctly? Here, we show how learning theory can offer an elegant solution to this seemingly intractable puzzle in language acquisition. From it, we derived formal predictions about word learning in situations of Quinean ambiguity, and subsequently tested our predictions on toddlers, undergraduates, and developmental psychologists. The toddlers’ performance was consistent both with our predictions and with the workings of implicit mechanisms that can facilitate the learning of meaningful lexical systems. Adults adopted a markedly different and likely suboptimal strategy. These results suggest one explanation for why early word learning can appear baffling: Adult intuitions may be a poor source of insight into how children learn.
Authigenic iron oxide proxies for marine zinc over geological time and implications for eukaryotic metallome evolution
2013-04-22

Abstract Here, we explore enrichments in paleomarine Zn as recorded by authigenic iron oxides including Precambrian iron formations, ironstones, and Phanerozoic hydrothermal exhalites. This compilation of new and literature‐based iron formation analyses track dissolved Zn abundances and constrain the magnitude of the marine reservoir over geological time. Overall, the iron formation record is characterized by a fairly static range in Zn/Fe ratios throughout the Precambrian, consistent with the shale record (Scott et al ., 2013, Nature Geoscience, 6 , 125–128). When hypothetical partitioning scenarios are applied to this record, paleomarine Zn concentrations within about an order of magnitude of modern are indicated. We couple this examination with new chemical speciation models to interpret the iron formation record. We present two scenarios: first, under all but the most sulfidic conditions and with Zn‐binding organic ligand concentrations similar to modern oceans, the amount of bioavailable Zn remained relatively unchanged through time. Late proliferation of Zn in eukaryotic metallomes has previously been linked to marine Zn biolimitation, but under this scenario the expansion in eukaryotic Zn metallomes may be better linked to biologically intrinsic evolutionary factors. In this case, zinc‘s geochemical and biological evolution may be decoupled and viewed as a function of increasing need for genome regulation and diversification of Zn‐binding transcription factors. In the second scenario, we consider Archean organic ligand complexation in such excess that it may render Zn bioavailability low. However, this is dependent on Zn–organic ligand complexes not being bioavailable, which remains unclear. In this case, although bioavailability may be low, sphalerite precipitation is prevented, thereby maintaining a constant Zn inventory throughout both ferruginous and euxinic conditions. These results provide new perspectives and constraints on potential couplings between the trajectory of biological and marine geochemical coevolution.
Short-Term In-Vitro Expansion Improves Monitoring and Allows Affordable Generation of Virus-Specific T-Cells against Several Viruses for a Broad Clinical Application
2013-04-22

Adenoviral infections are a major cause of morbidity and mortality after allogeneic hematopoietic stem cell transplantation (HSCT) in pediatric patients. Adoptive transfer of donor-derived human adenovirus (HAdV)-specific T-cells represents a promising treatment option. However, the difficulty in identifying and selecting rare HAdV-specific T-cells, and the short time span between patients at high risk for invasive infection and viremia are major limitations. We therefore developed an IL-15-driven 6 to 12 day short-term protocol for in vitro detection of HAdV-specific T cells, as revealed by known MHC class I multimers and a newly identified adenoviral CD8 T-cell epitope derived from the E1A protein for the frequent HLA-type A*02∶01 and IFN-γ. Using this novel and improved diagnostic approach we observed a correlation between adenoviral load and reconstitution of CD8(+) and CD4(+) HAdV-specific T-cells including central memory cells in HSCT-patients. Adaption of the 12-day protocol to good manufacturing practice conditions resulted in a 2.6-log (mean) expansion of HAdV-specific T-cells displaying high cytolytic activity (4-fold) compared to controls and low or absent alloreactivity. Similar protocols successfully identified and rapidly expanded CMV-, EBV-, and BKV-specific T-cells. Our approach provides a powerful clinical-grade convertible tool for rapid and cost-effective detection and enrichment of multiple virus-specific T-cells that may facilitate broad clinical application.