814 research outputs found
Expression and function of transient receptor potential channels in the female bovine reproductive tract
© 2016 Elsevier Inc. The epithelium lining the oviduct is critical for early reproductive events, many of which are mediated via intracellular calcium ions. Despite this, little is known about the regulation of calcium homeostasis in the oviductal epithelium. Epithelial transient receptor potential channels (TRPCs) modulate calcium flux in other tissues, and their expression and functional regulation have therefore been examined using the bovine oviduct as a model for the human. The effects of FSH, LH, 17β-estradiol, and progesterone on TRPCs expression and intracellular calcium flux were determined. Transient receptor potential channels 1, 2, 3, 4, and 6 were expressed in the bovine reproductive tract, and their gene expression varied throughout the estrous cycle. In more detailed studies undertaken on TRPC1 and 6, we show that protein expression varied through the estrus cycle; specifically, 17β-estradiol, FSH, and LH individually and in combination upregulated TRPC1 and 6 expression in cultured bovine oviduct epithelial cells although progesterone antagonized these effects. Functional studies showed changes in calcium mobilization in bovine oviduct epithelial cells were dependent on TRPCs. In conclusion, TRPC1, 2, 3, 4, and 6 are present in the epithelium lining the bovine oviduct, and TRPC1 and 6 vary through the estrous cycle suggesting an important role in early reproductive function
A Semi-Analytical Analysis of Texture Collapse
This study presents a simplified approach to studying the dynamics of global
texture collapse. We derive equations of motion for a spherically symmetric
field configuration using a two parameter ansatz. Then we analyse the effective
potential for the resulting theory to understand possible trajectories of the
field configuration in the parameter space of the ansatz. Numerical results are
given for critical winding and collapse time in spatially flat non-expanding,
and flat expanding universes. In addition, the open non-expanding and
open-expanding cases are studied.Comment: 12 pages, figures available from author, BROWN-HET-895, uses phyzz
Reparametrising the Skyrme Model using the Lithium-6 Nucleus
The minimal energy B=6 solution of the Skyrme model is a static soliton with
symmetry. The symmetries of the solution imply that the quantum
numbers of the ground state are the same as those of the Lithium-6 nucleus.
This identification is considered further by obtaining expressions for the mean
charge radius and quadrupole moment, dependent only on the Skyrme model
parameters (a dimensionless constant) and (the pion decay
constant). The optimal values of these parameters have often been deliberated
upon, and we propose, for , changing them from those which are most
commonly accepted. We obtain specific values for these parameters for B=6, by
matching with properties of the Lithium-6 nucleus. We find further support for
the new values by reconsidering the -particle and deuteron as quantized
B=4 and B=2 Skyrmions.Comment: 18 page
The Darboux-Backlund transformation for the static 2-dimensional continuum Heisenberg chain
We construct the Darboux-Backlund transformation for the sigma model
describing static configurations of the 2-dimensional classical continuum
Heisenberg chain. The transformation is characterized by a non-trivial
normalization matrix depending on the background solution. In order to obtain
the transformation we use a new, more general, spectral problem.Comment: 12 page
Non-Singular Stationary Global Strings
A field-theoretical model for non-singular global cosmic strings is
presented. The model is a non-linear sigma model with a potential term for a
self-gravitating complex scalar field. Non-singular stationary solutions with
angular momentum and possibly linear momentum are obtained by assuming an
oscillatory dependence of the scalar field on t, phi and z. This dependence has
an effect similar to gauging the global U(1) symmetry of the model, which is
actually a Kaluza-Klein reduction from four to three spacetime dimensions. The
method of analysis can be regarded as an extension of the
gravito-electromagnetism formalism beyond the weak field limit. Some D=3
self-dual solutions are also discussed.Comment: 20 pages Latex, 12 PS figures included. Minor corrections. Version to
appear in Phys.Rev.
Zero mode quantization of multi-Skyrmions
A zero mode quantization of the minimal energy SU(2) Skyrmions for nucleon
numbers four to nine and seventeen is described. This involves quantizing the
rotational and isorotational modes of the configurations. For nucleon numbers
four, six and eight the ground states obtained are in agreement with the
observed nuclear states of Helium, Lithium and Beryllium. However, for nucleon
numbers five, seven, nine and seventeen the spins obtained conflict with the
observed isodoublet nuclear states.Comment: 37 pages, LaTeX, 4 figures. More careful treatment of double covers,
reference adde
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