169 research outputs found
Anatomy of an exhumed debrite and impact on stratal architecture
Submarine debrites generate complicated patterns of seabed relief which in uence subsequent ow behaviour and depositional patterns. However, recognizing this interaction in subsurface data is challenging in seismic and well data. To bridge this resolution gap, large-scale outcrop analogues can be used. The early post-rift Middle Jurassic succession of the Los Molles Formation is well-exposed along a 10 km long and downdip-orientated W-E outcrop belt located the western Central Neuquen Basin, Argentina.Fil: Martanez Donate, Ander. University of Manchester; Reino UnidoFil: Privat, Aurelia. University of Leeds; Reino UnidoFil: Spychala, Yvonne. Leibniz Universitat Hannover; AlemaniaFil: Hodgson, David. University of Leeds; Reino UnidoFil: Jackson, Christopher A. L.. Imperial College London; Reino UnidoFil: Kane, Ian. University of Manchester; Reino UnidoFil: Schwarz, Ernesto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones Geológicas. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Investigaciones Geológicas; ArgentinaFil: Flint, Stephen S.. University of Manchester; Reino Unido59th British Sedimentological Research Group Annual General MeetingLiverpoolReino UnidoBritish Sedimentological Research GroupUniversity of Liverpoo
Recognition criteria, characteristics and implications of the fluvial to marine transition zone in ancient deltaic deposits (Lajas Formation, Argentina)
The seaward end of modern rivers is characterized by the interactions of marine and fluvial processes, a tract known as the fluvial to marine transition zone, which varies between systems due to the relative strength of these processes. To understand how fluvial and tidal process interactions and the fluvial to marine transition zone are preserved in the rock record, large-scale outcrops of deltaic deposits of the Middle Jurassic Lajas Formation (Neuquen Basin, Argentina) have been investigated. Fluvial–tidal indicators consist of cyclically distributed carbonaceous drapes in unidirectional, seaward-oriented cross-stratifications, which are interpreted as the result of tidal modulation of the fluvial current in the inner part of the fluvial to marine transition zone. Heterolithic deposits with decimetre-scale interbedding of coarser-grained and finer-grained facies with mixed fluvial and tidal affinities are interpreted to indicate fluvial discharge fluctuations (seasonality) and subordinate tidal influence. Many other potential tidal indicators are argued to be the result of fluvial–tidal interactions with overall fluvial dominance or of purely fluvial processes. No purely tidal or tide-dominated facies were recognized in the studied deposits. Moreover, fluvial–tidal features are found mainly in deposits interpreted as interflood (forming during low river stage) in distal (delta front) or off-axis (interdistributary) parts of the system. Along major channel axes, the interpreted fluvial to marine transition zone is mainly represented by the fluvial-dominated section, whereas little or no tide-dominated section is identified. The system is interpreted to have been hyposynchronous with a poorly developed turbidity maximum. These conditions and the architectural elements described, including major and minor distributary channels, terminal distributary channels, mouth bars and crevasse mouth bars, are consistent with an interpretation of a fluvial-dominated, tide-influenced delta system and with an estimated short backwater length and inferred microtidal conditions. The improved identification of process interactions, and their preservation in ancient fluvial to marine transition zones, is fundamental to refining interpretations of ancient deltaic successions.Centro de Investigaciones Geológica
Decoupling seasonal fluctuations in fluvial discharge from the tidal signature in ancient deltaic deposits: an example from the Neuquén Basin, Argentina
Fluvial discharge fluctuations are a fundamental characteristic of almost all modern rivers and can produce distinctive deposits that are rarely described from ancient fluvial or mixed-energy successions. Large-scale outcrops from the Middle Jurassic Lajas Formation (Argentina) expose a well-constrained stratigraphic succession of marginal-marine deposits with a strong fluvial influence and well-known tidal indicators. The studied deposits show decimetre-scale interbedding of coarser- and finer-grained facies with mixed fluvial and tidal affinities. The alternation of these two types of beds forms non-cyclic successions that are interpreted to be the result of seasonal variation in river discharge, rather than regular and predictable changes in current velocity caused by tides. Seasonal bedding is present in bar deposits that form within or at the mouth of minor and major channels. Seasonal bedding is not preserved in channel thalweg deposits, where river flood processes were too powerful, or in floodplain, muddy interdistributary-bay, prodelta and transgressive deposits, where the river signal was weak and sporadic. The identification of sedimentary facies characteristic of seasonal river discharge variations is important for accurate interpretation of ancient deltaic process regime
Nitration of Hsp90 induces cell death
Oxidative stress is a widely recognized cause of cell death associated with neurodegeneration, inflammation, and aging. Tyrosine nitration in these conditions has been reported extensively, but whether tyrosine nitration is a marker or plays a role in the cell-death processes was unknown. Here, we show that nitration of a single tyrosine residue on a small proportion of 90-kDa heat-shock protein (Hsp90), is sufficient to induce motor neuron death by the P2X7 receptor-dependent activation of the Fas pathway. Nitrotyrosine at position 33 or 56 stimulates a toxic gain of function that turns Hsp90 into a toxic protein. Using an antibody that recognizes the nitrated Hsp90, we found immunoreactivity in motor neurons of patients with amyotrophic lateral sclerosis, in an animal model of amyotrophic lateral sclerosis, and after experimental spinal cord injury. Our findings reveal that cell death can be triggered by nitration of a single protein and highlight nitrated Hsp90 as a potential target for the development of effective therapies for a large number of pathologies
Individual variation in hunger, energy intake and ghrelin responses to acute exercise
Purpose This study aimed to characterize the immediate and extended effect of acute exercise on hunger, energy intake, and circulating acylated ghrelin concentrations using a large data set of homogenous experimental trials and to describe the variation in responses between individuals.
Methods Data from 17 of our group's experimental crossover trials were aggregated yielding a total sample of 192 young, healthy males. In these studies, single bouts of moderate to high-intensity aerobic exercise (69% ± 5% V˙O2 peak; mean ± SD) were completed with detailed participant assessments occurring during and for several hours postexercise. Mean hunger ratings were determined during (n = 178) and after (n = 118) exercise from visual analog scales completed at 30-min intervals, whereas ad libitum energy intake was measured within the first hour after exercise (n = 60) and at multiple meals (n = 128) during the remainder of trials. Venous concentrations of acylated ghrelin were determined at strategic time points during (n = 118) and after (n = 89) exercise.
Results At group level, exercise transiently suppressed hunger (P < 0.010, Cohen's d = 0.77) but did not affect energy intake. Acylated ghrelin was suppressed during exercise (P < 0.001, Cohen's d = 0.10) and remained significantly lower than control (no exercise) afterward (P < 0.024, Cohen's d = 0.61). Between participants, there were notable differences in responses; however, a large proportion of this spread lay within the boundaries of normal variation associated with biological and technical assessment error.
Conclusion In young men, acute exercise suppresses hunger and circulating acylated ghrelin concentrations with notable diversity between individuals. Care must be taken to distinguish true interindividual variation from random differences within normal limits
Cell-free H-cluster Synthesis and [FeFe] Hydrogenase Activation: All Five CO and CN− Ligands Derive from Tyrosine
[FeFe] hydrogenases are promising catalysts for producing hydrogen as a sustainable fuel and chemical feedstock, and they also serve as paradigms for biomimetic hydrogen-evolving compounds. Hydrogen formation is catalyzed by the H-cluster, a unique iron-based cofactor requiring three carbon monoxide (CO) and two cyanide (CN−) ligands as well as a dithiolate bridge. Three accessory proteins (HydE, HydF, and HydG) are presumably responsible for assembling and installing the H-cluster, yet their precise roles and the biosynthetic pathway have yet to be fully defined. In this report, we describe effective cell-free methods for investigating H-cluster synthesis and [FeFe] hydrogenase activation. Combining isotopic labeling with FTIR spectroscopy, we conclusively show that each of the CO and CN− ligands derive respectively from the carboxylate and amino substituents of tyrosine. Such in vitro systems with reconstituted pathways comprise a versatile approach for studying biosynthetic mechanisms, and this work marks a significant step towards an understanding of both the protein-protein interactions and complex reactions required for H-cluster assembly and hydrogenase maturation
Immune response CC chemokines CCL2 and CCL5 are associated with pulmonary sarcoidosis
Abstract Background Pulmonary sarcoidosis involves an intense leukocyte infiltration of the lung with the formation of non-necrotizing granulomas. CC chemokines (chemokine (C-C motif) ligand 2 (CCL2)-CCL5) are chemoattractants of mononuclear cells and act through seven transmembrane G-coupled receptors. Previous studies have demonstrated conflicting results with regard to the associations of these chemokines with sarcoidosis. In an effort to clarify previous discrepancies, we performed the largest observational study to date of CC chemokines in bronchoalveolar lavage fluid (BALF) from patients with pulmonary sarcoidosis. Results BALF chemokine levels from 72 patients affected by pulmonary sarcoidosis were analyzed by enzyme-linked immunosorbent assay (ELISA) and compared to 8 healthy volunteers. BALF CCL3 and CCL4 levels from pulmonary sarcoidosis patients were not increased compared to controls. However, CCL2 and CCL5 levels were elevated, and subgroup analysis showed higher levels of both chemokines in all stages of pulmonary sarcoidosis. CCL2, CCL5, CC chemokine receptor type 1 (CCR1), CCR2 and CCR3 were expressed from mononuclear cells forming the lung granulomas, while CCR5 was only found on mast cells. Conclusions These data suggest that CCL2 and CCL5 are important mediators in recruiting CCR1, CCR2, and CCR3 expressing mononuclear cells as well as CCR5-expressing mast cells during all stages of pulmonary sarcoidosis
Maize Genomes to Fields: 2014 and 2015 field season genotype, phenotype, environment, and inbred ear image datasets
Objectives: Crop improvement relies on analysis of phenotypic, genotypic, and environmental data. Given large, well-integrated, multi-year datasets, diverse queries can be made: Which lines perform best in hot, dry environments? Which alleles of specific genes are required for optimal performance in each environment? Such datasets also can be leveraged to predict cultivar performance, even in uncharacterized environments. The maize Genomes to Fields (G2F) Initiative is a multi-institutional organization of scientists working to generate and analyze such datasets from existing, publicly available inbred lines and hybrids. G2F’s genotype by environment project has released 2014 and 2015 datasets to the public, with 2016 and 2017 collected and soon to be made available.
Data description: Datasets include DNA sequences; traditional phenotype descriptions, as well as detailed ear, cob, and kernel phenotypes quantified by image analysis; weather station measurements; and soil characterizations by site. Data are released as comma separated value spreadsheets accompanied by extensive README text descriptions. For genotypic and phenotypic data, both raw data and a version with outliers removed are reported. For weather data, two versions are reported: a full dataset calibrated against nearby National Weather Service sites and a second calibrated set with outliers and apparent artifacts removed
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