University of Oklahoma

About: University of Oklahoma is a education organization based out in Norman, Oklahoma, United States. It is known for research contribution in the topics: Population & Radar. The organization has 25269 authors who have published 52609 publications receiving 1821706 citations. The organization is also known as: OU & Oklahoma University.

Effect of flow perfusion on the osteogenic differentiation of bone marrow stromal cells cultured on starch-based three-dimensional scaffolds.

Abstract: This study aims to investigate the effect of culturing conditions (static and flow perfusion) on the proliferation and osteogenic differentiation of rat bone marrow stromal cells seeded on two novel scaffolds exhibiting distinct porous structures. Specifically, scaffolds based on SEVA-C (a blend of starch with ethylene vinyl alcohol) and SPCL (a blend of starch with polycaprolactone) were examined in static and flow perfusion culture. SEVA-C scaffolds were formed using an extrusion process, whereas SPCL scaffolds were obtained by a fiber bonding process. For this purpose, these scaffolds were seeded with marrow stromal cells harvested from femoras and tibias of Wistar rats and cultured in a flow perfusion bioreactor and in 6-well plates for 3, 7, and 15 days. The proliferation and alkaline phosphatase activity patterns were similar for both types of scaffolds and for both culture conditions. However, calcium content analysis revealed a significant enhancement of calcium deposition on both scaffold types cultured under flow perfusion. This observation was confirmed by Von Kossa-stained sections and tetracycline fluorescence. Histological analysis and confocal images of the cultured scaffolds showed a much better distribution of cells within the SPCL scaffolds than the SEVA-C scaffolds, which had limited pore interconnectivity, under flow perfusion conditions. In the scaffolds cultured under static conditions, only a surface layer of cells was observed. These results suggest that flow perfusion culture enhances the osteogenic differentiation of marrow stromal cells and improves their distribution in three-dimensional, starch-based scaffolds. They also indicate that scaffold architecture and especially pore interconnectivity affect the homogeneity of the formed tissue.

Responses of ecosystem nitrogen cycle to nitrogen addition: a meta-analysis

Abstract: Summary •Anthropogenic nitrogen (N) addition may substantially alter the terrestrial N cycle. However, a comprehensive understanding of how the ecosystem N cycle responds to external N input remains elusive. •Here, we evaluated the central tendencies of the responses of 15 variables associated with the ecosystem N cycle to N addition, using data extracted from 206 peer-reviewed papers. •Our results showed that the largest changes in the ecosystem N cycle caused by N addition were increases in soil inorganic N leaching (461%), soil NO3− concentration (429%), nitrification (154%), nitrous oxide emission (134%), and denitrification (84%). N addition also substantially increased soil NH4+ concentration (47%), and the N content in belowground (53%) and aboveground (44%) plant pools, leaves (24%), litter (24%) and dissolved organic N (21%). Total N content in the organic horizon (6.1%) and mineral soil (6.2%) slightly increased in response to N addition. However, N addition induced a decrease in microbial biomass N by 5.8%. •The increases in N effluxes caused by N addition were much greater than those in plant and soil pools except soil NO3−, suggesting a leaky terrestrial N system.

Electron and photon energy calibration with the ATLAS detector using LHC Run 1 data

Abstract: This paper presents the electron and photon energy calibration achieved with the ATLAS detector using about 25 fb(-1) of LHC proton-proton collision data taken at centre-of-mass energies of root s = 7 and 8 TeV. The reconstruction of electron and photon energies is optimised using multivariate algorithms. The response of the calorimeter layers is equalised in data and simulation, and the longitudinal profile of the electromagnetic showers is exploited to estimate the passive material in front of the calorimeter and reoptimise the detector simulation. After all corrections, the Z resonance is used to set the absolute energy scale. For electrons from Z decays, the achieved calibration is typically accurate to 0.05% in most of the detector acceptance, rising to 0.2% in regions with large amounts of passive material. The remaining inaccuracy is less than 0.2-1% for electrons with a transverse energy of 10 GeV, and is on average 0.3% for photons. The detector resolution is determined with a relative inaccuracy of less than 10% for electrons and photons up to 60 GeV transverse energy, rising to 40% for transverse energies above 500 GeV.

Software for the frontiers of quantum chemistry: An overview of developments in the Q-Chem 5 package

Abstract: This article summarizes technical advances contained in the fifth major release of the Q-Chem quantum chemistry program package, covering developments since 2015. A comprehensive library of exchange-correlation functionals, along with a suite of correlated many-body methods, continues to be a hallmark of the Q-Chem software. The many-body methods include novel variants of both coupled-cluster and configuration-interaction approaches along with methods based on the algebraic diagrammatic construction and variational reduced density-matrix methods. Methods highlighted in Q-Chem 5 include a suite of tools for modeling core-level spectroscopy, methods for describing metastable resonances, methods for computing vibronic spectra, the nuclear-electronic orbital method, and several different energy decomposition analysis techniques. High-performance capabilities including multithreaded parallelism and support for calculations on graphics processing units are described. Q-Chem boasts a community of well over 100 active academic developers, and the continuing evolution of the software is supported by an "open teamware" model and an increasingly modular design.

Physiology, Ecology, Phylogeny, and Genomics of Microorganisms Capable of Syntrophic Metabolism

Abstract: Syntrophic metabolism is diverse in two respects: phylogenetically with microorganisms capable of syntrophic metabolism found in the Deltaproteobacteria and in the low G+C gram-positive bacteria, and metabolically given the wide variety of compounds that can be syntrophically metabolized. The latter includes saturated fatty acids, unsaturated fatty acids, alcohols, and hydrocarbons. Besides residing in freshwater and marine anoxic sediments and soils, microbes capable of syntrophic metabolism also have been observed in more extreme habitats, including acidic soils, alkaline soils, thermal springs, and permanently cold soils, demonstrating that syntrophy is a widely distributed metabolic process in nature. Recent ecological and physiological studies show that syntrophy plays a far larger role in carbon cycling than was previously thought. The availability of the first complete genome sequences for four model microorganisms capable of syntrophic metabolism provides the genetic framework to begin dissecting the biochemistry of the marginal energy economies and interspecies interactions that are characteristic of the syntrophic lifestyle.