Effects of bTP-1 and oxytocin on prostaglandin and protein production by the bovine endometrium

There is evidence that conceptal proteins in general, and bovine trophoblast protein-1 (bTP-1) specifically, alter biochemical mechanisms which are responsible for returning cattle to estrus. Endometrial explants, gland fragments, glandular epithelial cells, and stromal cells from uteri of cyclic cows (N=4) were cultured in medium containing 1 ug/ml bovine serum albumen (BSA), 1 ug bovine trophoblast protein-1 (bTP-1), 50 mU oxytocin after 8 h, or 1 ug/ml bTP-1 followed by 50 mU oxytocin at 8 h and examined their effects on prostaglandin and protein secretion. Explants treated with bTP-1 secreted less Prostaglandin F2α (PGF2α) than explants receiving BSA (P\u3c0.05) or oxytocin alone (P\u3c0.001). Oxytocin treated tissue or cells secreted significantly more PGF2α than bTP-1 treatments (P\u3c0.05) and BSA treatments (P\u3c0.05) in all cultures. Glandular epithelial cell cultures treated with oxytocin secreted more prostaglandin E2 (P, 0.05) than cultures treated with BSA or bTP-1. Glandular epithelial cells produced more PGF2α than any other group when normalized to total cellular protein, while stromal cells produced more PGE2. There was no effect of treatment on incorporation of radiolabeled methionine and cysteine into macromolecules although stromal cells incorporated more radiolabel than other cell or tissue type. Two-dimensional-SDS PAGE and fluorography revealed that similar proteins were secreted by explants, glandular epithelial cells, and intact gland fragments but no differences were observed due to treatment. These results indicate bTP-1 and/or oxytocin affect prostaglandin secretion in in vitro models of the bovine endometrium in manner that helps explain in vivo observations

A Study of an Alternative Program and/or School for the Creative and Performing Arts in the Pike County School System

An applied project submitted in partial fulfillment of the requirements for the degree of Education Specialist at Morehead State University by Roger D. Johnson in 1990

Magnetically-induced ferroelectricity in the (ND4)2[FeCl5(D2O)] molecular compound

The number of magnetoelectric multiferroic materials reported to date is scarce, as magnetic structures that break inversion symmetry and induce an improper ferroelectric polarization typically arise through subtle competition between different magnetic interactions. The (NH4)2[FeCl5(H2O)] compound is a rare case where such improper ferroelectricity has been observed in a molecular material. We have used single crystal and powder neutron diffraction to obtain detailed solutions for the crystal and magnetic structures of (NH4)2[FeCl5(H2O)], from which we determined the mechanism of multiferroicity. From the crystal structure analysis, we observed an order-disorder phase transition related to the ordering of the ammonium counterion. We have determined the magnetic structure below TN, at 2K and zero magnetic field, which corresponds to a cycloidal spin arrangement with magnetic moments contained in the ac-plane, propagating parallel to the c-axis. The observed ferroelectricity can be explained, from the obtained magnetic structure, via the inverse Dzyaloshinskii-Moriya mechanism

Reexamining Student-Athlete GPA: Traditional vs. Athletic Variables

A sample of 674 first-year student-athletes at a midsize Midwestern university were examined each year over a five-year period (2004–2008) to determine if athletic variables were powerful enough to be used in conjunction with traditional predictors of college success to predict GPA. The four specific athletic variables unique to student-athletes (i.e., sport, coaching change, playing time, team winning percentage), were hypothesized to be as predictive as traditional variables. Pearson correlations revealed student-athletes were more likely to earn a high first-year GPA if they were female (r = .35), Caucasian (r = -.33), scored well on standardized tests (r = -.47), had a respectable high school GPA (r = .64), were ranked high in their graduating high school class (r = -.58), had a relatively large high school graduating class (r = .15) were not undecided about major (r = -.11), were not a member of a revenue sport (r = .33), and earned a considerable amount of playing time in their first year (r = -.15). Least squares linear regression demonstrated the traditional variables of gender (B = .16), race (B = -.26), standardized test scores (B = .03), high school GPA (B = .41), high school rank (B < -.01), and size of high school graduating class (B < .01) were most influential in predicting first-year student-athlete GPA

Magnetoelectric domains and their switching mechanism in a Y-type hexaferrite

By employing resonant X-ray microdiffraction, we image the magnetisation and magnetic polarity domains of the Y-type hexaferrite Ba$_{0.5}$Sr$_{1.5}$Mg$_2$Fe$_{12}$O$_{22}$. We show that the magnetic polarity domain structure can be controlled by both magnetic and electric fields, and that full inversion of these domains can be achieved simply by reversal of an applied magnetic field in the absence of an electric field bias. Furthermore, we demonstrate that the diffraction intensity measured in different X-ray polarisation channels cannot be reproduced by the accepted model for the polar magnetic structure, known as the 2-fan transverse conical (TC) model. We propose a modification to this model, which achieves good quantitative agreement with all of our data. We show that the deviations from the TC model are large, and may be the result of an internal magnetic chirality, most likely inherited from the parent helical (non-polar) phase.Comment: 9 figure

Weak ferromagnetism and spin reorientation in antiferroelectric BiCrO3

BiCrO3 is an antiferroelectric perovskite known to exhibit an unconventional spin reorientation transition between antiferromagnetic structures, accompanied by a large jump in weak ferromagnetism. Using a combination of neutron powder diffraction, magnetometry, and symmetry analysis, we confirm the dominant G-type antiferromagnetic order below TN = 111 K and identify the magnetic phase transition with a spontaneous rotation of Cr3+ moments from the b axis to a particular direction in the ac plane. We demonstrate the role of antiferroelectric displacements produced by the Bi3+ lone-pair electrons and octahedral rotations in establishing spin canting via the antisymmetric Dzyaloshinskii-Moriya interaction. This mechanism results in weak ferromagnetism above and below the spin-reorientation and explains the dramatic increase in net magnetization on cooling

Gapless spin-liquid state in the structurally disorder-free triangular antiferromagnet NaYbO2_2

We present the structural characterization and low-temperature magnetism of the triangular-lattice delafossite NaYbO$_2$. Synchrotron x-ray diffraction and neutron scattering exclude both structural disorder and crystal-electric-field randomness, whereas heat-capacity measurements and muon spectroscopy reveal the absence of magnetic order and persistent spin dynamics down to at least 70\,mK. Continuous magnetic excitations with the low-energy spectral weight accumulating at the $K$-point of the Brillouin zone indicate the formation of a novel spin-liquid phase in a triangular antiferromagnet. This phase is gapless and shows a non-trivial evolution of the low-temperature specific heat. Our work demonstrates that NaYbO$_2$ practically gives the most direct experimental access to the spin-liquid physics of triangular antiferromagnets.Comment: 6 pages, 4figure

Emergent helical texture of electric dipoles

Long-range ordering of magnetic dipoles in bulk materials gives rise to a broad range of magnetic structures, from simple collinear ferromagnets and antiferromagnets, to complex magnetic helicoidal textures stabilized by competing exchange interactions. In contrast, in the context of dipolar order in dielectric crystals, only parallel (ferroelectric) and antiparallel (antiferroelectric) collinear alignments of electric dipoles are typically considered. Here, we report an observation of incommensurate helical ordering of electric dipoles by light hole-doping of the quadruple perovskite BiMn7O12. In analogy with magnetism, the electric dipole helicoidal texture is also stabilized by competing instabilities. Specifically, orbital ordering and lone electron pair stereochemical activity compete, giving rise to phase transitions from a non-chiral cubic structure, to an incommensurate electric dipole and orbital helix, via an intermediate density wave

Switching of ferrotoroidal domains via an intermediate mixed state in the multiferroic Y-type hexaferrite Ba0.5_{0.5}Sr1.5_{1.5}Mg2_2Fe12_{12}O22_{22}

We report a detailed study of the magnetic field switching of ferrotoroidal/multiferroic domains in the Y-type hexaferrite compound Ba$_{0.5}$Sr$_{1.5}$Mg$_2$Fe$_{12}$O$_{22}$. By combining data from SQUID magnetometry, magneto-current measurements, and resonant X-ray scattering experiments, we arrive at a complete description of the deterministic switching, which involves the formation of a temperature-dependent mixed state in low magnetic fields. This mechanism is likely to be shared by other members of the hexaferrite family, and presents a challenge for the development of high-speed read-write memory devices based on these materials.Comment: 20 pages, 7 figures, 2 table