Magnons in Ferromagnetic Metallic Manganites

Ferromagnetic (FM) manganites, a group of likely half-metallic oxides, are of special interest not only because they are a testing ground of the classical doubleexchange interaction mechanism for the colossal magnetoresistance, but also because they exhibit an extraordinary arena of emergent phenomena. These emergent phenomena are related to the complexity associated with strong interplay between charge, spin, orbital, and lattice. In this review, we focus on the use of inelastic neutron scattering to study the spin dynamics, mainly the magnon excitations in this class of FM metallic materials. In particular, we discussed the unusual magnon softening and damping near the Brillouin zone boundary in relatively narrow band compounds with strong Jahn-Teller lattice distortion and charge/orbital correlations. The anomalous behaviors of magnons in these compounds indicate the likelihood of cooperative excitations involving spin, lattice, as well as orbital degrees of freedom.Comment: published in J. Phys.: Cond. Matt. 20 figure

Randomized comparison of group versus individual educational interventions for pregnant women to reduce their secondhand smoke exposure

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Schedulability Analysis for Certification-friendly Multicore Systems

This paper presents a new schedulability test for safety-critical software undergoing a transition from single-core to multicore systems - a challenge faced by multiple industries today. Our migration model, consisting of a schedulability test and execution model, is distinguished by three aspects consistent with reducing transition cost. First, it assumes externally-driven scheduling parameters, such as periods and deadlines, remain fixed (and thus known), whereas exact computation times are not. Second, it adopts a globally synchronized conflict-free I/O model that leads to a decoupling between cores, simplifying the schedulability analysis. Third, it employs global priority assignment across all tasks on each core, irrespective of application, where budget constraints on each application ensure isolation. These properties enable us to obtain a utilization bound that places an allowable limit on total task execution times. Evaluation results demonstrate the advantages of our scheduling model over competing resource partitioning approaches, such as Periodic Server and TDMA.Ope

Evolution of spin-wave excitations in ferromagnetic metallic manganites

Neutron scattering results are presented for spin-wave excitations of three ferromagnetic metallic $A_{1-x}A^{\prime}_{x}$MnO$_3$ manganites (where $A$ and $A^\prime$ are rare- and alkaline-earth ions), which when combined with previous work elucidate systematics of the interactions as a function of carrier concentration $x$, on-site disorder, and strength of the lattice distortion. The long wavelength spin dynamics show only a very weak dependence across the series. The ratio of fourth to first neighbor exchange ($J_4/J_1$) that controls the zone boundary magnon softening changes systematically with $x$, but does not depend on the other parameters. None of the prevailing models can account for these behaviors.Comment: Submitted to Phys. Rev. Let

Signature of Magnetic Phase Separation in the Ground State of Pr1-xCaxMnO3

Neutron scattering has been used to investigate the evolution of the long- and short-range charge-ordered (CO), ferromagnetic (FM), and antiferromagnetic (AF) correlations in single crystals of Pr1-xCaxMnO3. The existence and population of spin clusters as refected by short-range correlations are found to drastically depend on the doping (x) and temperature (T). Concentrated spin clusters coexist with long-range canted AF order in a wide temperature range in x = 0.3 while clusters do not appear in x = 0.4 crystal. In contrast, both CO and AF order parameters in the x = 0.35 crystal show a precipitous decrease below ~ 35 K where spin clusters form. These results provide direct evidence of magnetic phase separation and indicate that there is a critical doping x_c (close to x = 0.35) that divides the phase-separated site-centered from the homogeneous bond-centered or charge-disproportionated CO ground state.Comment: 4 pages, 4 figures, submitted to Phys. Rev. Letter

Preparation and Characteristic of Dextran-BSA Antibody and Establishment of it’s Elisa Immunoassay

The enzyme linked immunosorbent assay (ELISA) is a potential tool for the determination of dextran. In this study, dextran–BSA antigens were prepared by Reductive amination method, and were confirmed by SDS-PAGE and free amino detection. The effects of coupled reaction conditions such as different oxidation degree of dextran, the reaction time were investigated and the immunity of the resulting dextran- BSA neoglycoprotein antigens were evaluated through the interaction with standard dextran antibody. The immunogen was immunized with white rabbits to obtained polyclonal antibody respectively. A general and broad class-specific Elisa detection method was developed according to Elisa theory. The method was put to use for quantitative analysis of dextran in practical saccharose samples

A Contour Integral Representation for the Dual Five-Point Function and a Symmetry of the Genus Four Surface in R6

The invention of the "dual resonance model" N-point functions BN motivated the development of current string theory. The simplest of these models, the four-point function B4, is the classical Euler Beta function. Many standard methods of complex analysis in a single variable have been applied to elucidate the properties of the Euler Beta function, leading, for example, to analytic continuation formulas such as the contour-integral representation obtained by Pochhammer in 1890. Here we explore the geometry underlying the dual five-point function B5, the simplest generalization of the Euler Beta function. Analyzing the B5 integrand leads to a polyhedral structure for the five-crosscap surface, embedded in RP5, that has 12 pentagonal faces and a symmetry group of order 120 in PGL(6). We find a Pochhammer-like representation for B5 that is a contour integral along a surface of genus five. The symmetric embedding of the five-crosscap surface in RP5 is doubly covered by a symmetric embedding of the surface of genus four in R6 that has a polyhedral structure with 24 pentagonal faces and a symmetry group of order 240 in O(6). The methods appear generalizable to all N, and the resulting structures seem to be related to associahedra in arbitrary dimensions.Comment: 43 pages and 44 figure

Retrievals of XCO2_{CO2}, XCH4_{CH4} and XCO_{CO} from portable, near-infrared Fourier transform spectrometer solar observations in Antarctica

The COllaborative Carbon Column Observing Network (COCCON) uses low-resolution, portable EM27/SUN Fourier transform spectrometers (FTSs) to make retrievals of column-averaged dry-air mole fractions (DMFs, represented as X$_{gas}$) of CO$_{2}$, CH$_{4}$, CO and H$_{2}$O from near-infrared solar absorption spectra. The COCCON has developed rapidly over recent years and complements the Total Carbon Column Observing Network (TCCON). In this work, we provide details of the first seasonal time series of near-infrared X$_{CO2}$, X$_{CH4}$ and X$_{CO}$ retrievals from measurements made in Antarctica during the deployment of an EM27/SUN to the Arrival Heights laboratory on Ross Island over the austral summer of 2019–2020 under the auspices of the COCCON. The DMFs of all three species were lower in Antarctica than at mid-latitude, and for X$_{CO2}$ and X$_{CO}$, the retrieved values were less variable. For X$_{CH4}$ however, the variability was significantly greater and it was found that this was strongly correlated to the proximity of the polar vortex. In order to ensure the stability of the instrument and the traceability of the retrievals, side-by-side comparisons to the TCCON station at Lauder, New Zealand and retrievals of the instrument line shape (ILS) were made before and after the measurements in Antarctica. These indicate that, over the course of the deployment, the instrument stability was such that the change in retrieved X$_{CO2}$ was well below 0.1%. The value of these data for satellite validation is demonstrated by making comparisons with the TROPOspheric Monitoring Instrument (TROPOMI) on the Sentinel-5 precursor (S5P) satellite. The dataset is available from the COCCON central facility hosted by the ESA Atmospheric Validation Data Centre (EVDC): https://doi.org/10.48477/coccon.pf10.arrivalheights.R02 (Pollard, 2021)

Optical and electrical properties of efficiency enhanced polymer solar cells with Au nanoparticles in a PEDOT-PSS layer

We unveil new device physics and provide details of device mechanisms by investigating polymer solar cells (PSCs) incorporating Au nanoparticles (NPs) into the hole collection poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) layer. Theoretical and experimental results show that the very strong near field around Au NPs due to Localized Surface Plasmonic Resonance (LSPR) mainly distributes laterally along the PEDOT:PSS layer rather than vertically into the adjacent active layer, leading to minimal enhancement of light absorption in the active layer. This finding can be extended to a typical class of solar cells incorporating metallic NPs in spacing layers adjacent to the active layer. With optical effects proven to be minor contributors to device performance improvements, we investigate the electrical properties of the PSCs and obtain insights into the detailed device mechanisms. Improvements in power conversion efficiency (PCE) of solar cells are found to originate from the enlarged active layer/PEDOT:PSS interfacial area and improved PEDOT:PSS conductivity. At high NP concentrations, reduced exciton quenching at donor/acceptor junctions is found to cause PCE deterioration. Our findings indicate that it is highly important to investigate both optical and electrical effects for understanding and optimizing PSC performances. © 2011 The Royal Society of Chemistry.postprin

Human C1q Induces Apoptosis in an Ovarian Cancer Cell Line via Tumor Necrosis Factor

Copyright: © 2016 Kaur, Sultan, Murugaiah, Pathan, Alhamlan, Karteris and Kishore. Human C1q is the first recognition subcomponent of the complement classical pathway that plays a vital role in the clearance of immune complexes, pathogens and apoptotic cells. C1q also has a homeostatic role involving immune and non-immune cells; these functions not necessarily involve complement activation. Recently, C1q has been shown to be expressed locally in the microenvironment of a range of human malignant tumours, where it can promote cancer cell adhesion, migration and proliferation, without involving complement activation. C1q has been shown to be present in the ascitic fluid formed during ovarian cancers. In this study, we have examined the effects of human C1q and its globular domain on an ovarian cancer cell line, SKOV3. We show that C1q and the recombinant globular modules induce apoptosis in SKOV3 cells in a dose-and time-dependent manner. C1q expression was not detectable in the SKOV3 cells. Exogenous treatment with C1q and globular heads at the concentration of 10μg/ml induced apoptosis in approximately 55% cells, as revealed by immunofluorescence microscopy and FACS. The qPCR and caspase analysis suggested that C1q and globular head modules activated TNF-α and upregulation of Fas. The genes of mTOR, RICTOR and RAPTOR survival pathways, which are often over-expressed in majority of the cancers, were significantly downregulated within few hours of the treatment of C1q and globular head modules. In conclusion, C1q, via its globular domain, induced apoptosis in an ovarian cancer cell line, SKOV3 via TNF-α induced apoptosis pathway involving upregulation of Bax and Fas. This study highlights a potentially protective role of C1q in certain cancers