1,706 research outputs found
Soft x-ray resonant magneto-optical Kerr effect as a depth-sensitive probe of magnetic heterogeneity: A simulation approach
We report a noticeable depth sensitivity of soft x-ray resonant magneto-optical Kerr effect able to resolve depth-varying magnetic heterostructures in ultrathin multilayer films. For various models of depth-varying magnetization orientations in an ultrathin Co layer of realistic complex layered structures, we have calculated the Kerr rotation, ellipticity, intensity spectra versus grazing incidence angle ??, and their hysteresis loops at different values of ?? for various photon energies ?? 's near the Co resonance regions. It is found from the simulation results that the Kerr effect has a much improved depth sensitivity and that its sensitivity varies remarkably with ?? and ?? in the vicinity of the resonance regions. These properties originate from a rich variety of wave interference effects superimposed with noticeable features of the refractive and absorptive optical effects near the resonance regions. Consequently, these allow us to resolve depth-varying magnetizations and their reversals varying with depth in a single magnetic layer and allow us to distinguish interface magnetism from the bulk properties in multilayer films. In this paper, the depth sensitivity of the Kerr effect with an atomic-scale resolution is demonstrated and discussed in details in several manners with the help of model simulations for various depth-varying spin configurations.open9
Understanding south korea’s use of sports mega-events for domestic, regional and international soft power
This paper seeks to contribute to the growing literature on ‘soft power’ by focusing on East Asia as a region gaining in political and economic significance; equally, we highlight the role sports mega-events play in the region’s most powerful states’ soft power strategies. For the purpose of this paper, we focus on South Korea’s soft power strategy and how the hosting of major sporting events has become a central part of this. We introduce both a novel tripartite approach to the study of the motives behind hosting sports mega-events, along with new, empirical data on the chosen case of South Korea. Our findings strengthen the notion that an explanation of why states seek to host major sports events can be better understood by considering the domestic, regional and international dimensions to capture the complexities behind such decisions
Design Rules for Self-Assembly of 2D Nanocrystal/Metal-Organic Framework Superstructures.
We demonstrate the guiding principles behind simple two dimensional self-assembly of MOF nanoparticles (NPs) and oleic acid capped iron oxide (Fe3 O4 ) NCs into a uniform two-dimensional bi-layered superstructure. This self-assembly process can be controlled by the energy of ligand-ligand interactions between surface ligands on Fe3 O4 NCs and Zr6 O4 (OH)4 (fumarate)6 MOF NPs. Scanning transmission electron microscopy (TEM)/energy-dispersive X-ray spectroscopy and TEM tomography confirm the hierarchical co-assembly of Fe3 O4 NCs with MOF NPs as ligand energies are manipulated to promote facile diffusion of the smaller NCs. First-principles calculations and event-driven molecular dynamics simulations indicate that the observed patterns are dictated by combination of ligand-surface and ligand-ligand interactions. This study opens a new avenue for design and self-assembly of MOFs and NCs into high surface area assemblies, mimicking the structure of supported catalyst architectures, and provides a thorough fundamental understanding of the self-assembly process, which could be a guide for designing functional materials with desired structure
Magnetic domain tuning and the emergence of bubble domains in the bilayer manganite La 2−2x Sr 1+2x Mn 2 O 7 (x=0.32)
We report a magnetic force microscopy study of the magnetic domain evolution in the layered manganite La2-2x Sr1+2x Mn2O7 (with x = 0.32). This strongly correlated electron compound is known to exhibit a wide range of magnetic phases, including a recently uncovered biskyrmion phase. We observe a continuous transition from dendritic to stripelike domains, followed by the formation of magnetic bubbles due to a field-and temperaturedependent competition between in-plane and out-of-plane spin alignments. The magnetic bubble phase appears at comparable field and temperature ranges as the biskyrmion phase, suggesting a close relation between both phases. Based on our real-space images we construct a temperature-field phase diagram for this composition.open115Ysciescopu
Scalable Purification and Characterization of the Anticancer Lunasin Peptide from Soybean
Lunasin is a peptide derived from the soybean 2S albumin seed protein that has both anticancer and anti-inflammatory activities. Large-scale animal studies and human clinical trials to determine the efficacy of lunasin in vivo have been hampered by the cost of synthetic lunasin and the lack of a method for obtaining gram quantities of highly purified lunasin from plant sources. The goal of this study was to develop a large-scale method to generate highly purified lunasin from defatted soy flour. A scalable method was developed that utilizes the sequential application of anion-exchange chromatography, ultrafiltration, and reversed-phase chromatography. This method generates lunasin preparations of >99% purity with a yield of 442 mg/kg defatted soy flour. Mass spectrometry of the purified lunasin revealed that the peptide is 44 amino acids in length and represents the original published sequence of lunasin with an additional C-terminal asparagine residue. Histone-binding assays demonstrated that the biological activity of the purified lunasin was similar to that of synthetic lunasin. This study provides a robust method for purifying commercial-scale quantities of biologically-active lunasin and clearly identifies the predominant form of lunasin in soy flour. This method will greatly facilitate the development of lunasin as a potential nutraceutical or therapeutic anticancer agent
The Kinetic Expansion of Solar-Wind Electrons: Transport Theory and Predictions for the very Inner Heliosphere
We propose a transport theory for the kinetic evolution of solar-wind electrons in the heliosphere. We derive a gyro-averaged kinetic transport equation that accounts for the spherical expansion of the solar wind and the geometry of the Parker-spiral magnetic field. To solve our three-dimensional kinetic equation, we develop a mathematical approach that combines the Crank--Nicolson scheme in velocity space and a finite-difference Euler scheme in configuration space. We initialize our model with isotropic electron distribution functions and calculate the kinetic expansion at heliocentric distances from 5 to 20 solar radii. In our kinetic model, the electrons evolve mainly through the combination of the ballistic particle streaming, the magnetic mirror force, and the electric field. By applying fits to our numerical results, we quantify the parameters of the electron strahl and core part of the electron velocity distributions. The strahl fit parameters show that the density of the electron strahl is around 7% of the total electron density at a distance of 20 solar radii, the strahl bulk velocity and strahl temperature parallel to the background magnetic field stay approximately constant beyond a distance of 15 solar radii, and (i.e., the ratio between strahl parallel thermal pressure to the magnetic pressure) is approximately constant with heliocentric distance at a value of about 0.02. We compare our results with data measured by Parker Solar Probe. Furthermore, we provide theoretical evidence that the electron strahl is not scattered by the oblique fast-magnetosonic/whistler instability in the near-Sun environment
Visualizing dimensionality reduction of systems biology data
One of the challenges in analyzing high-dimensional expression data is the
detection of important biological signals. A common approach is to apply a
dimension reduction method, such as principal component analysis. Typically,
after application of such a method the data is projected and visualized in the
new coordinate system, using scatter plots or profile plots. These methods
provide good results if the data have certain properties which become visible
in the new coordinate system and which were hard to detect in the original
coordinate system. Often however, the application of only one method does not
suffice to capture all important signals. Therefore several methods addressing
different aspects of the data need to be applied. We have developed a framework
for linear and non-linear dimension reduction methods within our visual
analytics pipeline SpRay. This includes measures that assist the interpretation
of the factorization result. Different visualizations of these measures can be
combined with functional annotations that support the interpretation of the
results. We show an application to high-resolution time series microarray data
in the antibiotic-producing organism Streptomyces coelicolor as well as to
microarray data measuring expression of cells with normal karyotype and cells
with trisomies of human chromosomes 13 and 21
Application of extended end composite pile design in pile foundation work
Pre-tensioned, spun, high-strength concrete (PHC) piles are the most commonly used type of pile in South Korea. Approximately 60% of the pile's strength is used in the design bearing capacity, and the rest is simply residing in the ground. Increasing the ground bearing capacity is crucial to reduce waste of the pile strength and to improve efficiency. Extended end (Ext) piles are a new kind of composite pile that can overcome the weakness of PHC piles. This study investigates the behaviour of Ext piles. Through field testing, it is confirmed that the bearing capacity of Ext piles is better than PHC piles by about 35% to 50%. Based on the study findings, the Ext pile design reduces the number of piles by around 38% compared to the PHC pile design through application in a selected construction site. The increased bearing capacity of Ext piles affects both work duration and project cost, which are 25% and 14% decreased, respectively
The role of the RACK1 ortholog Cpc2p in modulating pheromone-induced cell cycle arrest in fission yeast
The detection and amplification of extracellular signals requires the involvement of multiple protein components. In mammalian cells the receptor of activated C kinase (RACK1) is an important scaffolding protein for signal transduction networks. Further, it also performs a critical function in regulating the cell cycle by modulating the G1/S transition. Many eukaryotic cells express RACK1 orthologs, with one example being Cpc2p in the fission yeast Schizosaccharomyces pombe. In contrast to RACK1, Cpc2p has been described to positively regulate, at the ribosomal level, cells entry into M phase. In addition, Cpc2p controls the stress response pathways through an interaction with Msa2p, and sexual development by modulating Ran1p/Pat1p. Here we describe investigations into the role, which Cpc2p performs in controlling the G protein-mediated mating response pathway. Despite structural similarity to Gβ-like subunits, Cpc2p appears not to function at the G protein level. However, upon pheromone stimulation, cells overexpressing Cpc2p display substantial cell morphology defects, disorientation of septum formation and a significantly protracted G1 arrest. Cpc2p has the potential to function at multiple positions within the pheromone response pathway. We provide a mechanistic interpretation of this novel data by linking Cpc2p function, during the mating response, with its previous described interactions with Ran1p/Pat1p. We suggest that overexpressing Cpc2p prolongs the stimulated state of pheromone-induced cells by increasing ste11 gene expression. These data indicate that Cpc2p regulates the pheromone-induced cell cycle arrest in fission yeast by delaying cells entry into S phase
Advanced predictive quality control strategy involving different facilities
There are many industries that use highly technological solutions to improve quality in all of their products. The steel industry is one example. Several automatic surface-inspection systems are used in the steel industry to identify various types of defects and to help operators decide whether to accept, reroute, or downgrade the material, subject to the assessment process. This paper focuses on promoting a strategy that considers all defects in an integrated fashion. It does this by managing the uncertainty about the exact position of a defect due to different process conditions by means of Gaussian additive influence functions. The relevance of the approach is in making possible consistency and reliability between surface inspection systems. The results obtained are an increase in confidence in the automatic inspection system and an ability to introduce improved prediction and advanced routing models. The prediction is provided to technical operators to help them in their decision-making process. It shows the increase in improvement gained by reducing the 40 % of coils that are downgraded at the hot strip mill because of specific defects. In addition, this technology facilitates an increase of 50 % in the accuracy of the estimate of defect survival after the cleaning facility in comparison to the former approach. The proposed technology is implemented by means of software-based, multi-agent solutions. It makes possible the independent treatment of information, presentation, quality analysis, and other relevant functions
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