412 research outputs found
Role of the solar wind magnetic field in the interaction of a non-magnetized body with the solar wind: An electromagnetic 2-D particle-in-cell simulation
Rotating Kaluza-Klein Multi-Black Holes with Godel Parameter
We obtain new five-dimensional supersymmetric rotating multi-Kaluza-Klein
black hole solutions with the Godel parameter in the Einstein-Maxwell system
with a Chern-Simons term. These solutions have no closed timelike curve outside
the black hole horizons. At the infinity, the space-time is effectively
four-dimensional. Each horizon admits various lens space topologies
L(n;1)=S^3/Z_n in addition to a round S^3. The space-time can have outer
ergoregions disjointed from the black hole horizons, as well as inner
ergoregions attached to each horizon. We discuss the rich structures of
ergoregions.Comment: 19 pages, 4 figure
Squashed Kerr-Godel Black Holes - Kaluza-Klein Black Holes with Rotations of Black Hole and Universe -
Applying squashing transformation to Kerr-Godel black hole solutions, we
present a new type of a rotating Kaluza-Klein black hole solution to the
five-dimensional Einstein-Maxwell theory with a Chern-Simon term. The new
solutions generated via the squashing transformation have no closed timelike
curve everywhere outside the black hole horizons. At the infinity, the metric
asymptotically approaches a twisted S^1 bundle over a four-dimensional
Minkowski space-time. One of the remarkable features is that the solution has
two independent rotation parameters along an extra dimension associated with
the black hole's rotation and the Godel's rotation. The space-time also admits
the existence of two disconnected ergoregions, an inner ergoregion and an outer
ergoregion. These two ergoregions can rotate in the opposite direction as well
as in the same direction.Comment: 24 pages, 16 figure
Charged Rotating Kaluza-Klein Black Holes in Five Dimensions
We construct a new charged rotating Kaluza-Klein black hole solution in the
five-dimensional Einstein-Maxwell theory with a Chern-Simon term. The features
of the solutions are also investigated. The spacetime is asymptotically locally
flat, i.e., it asymptotes to a twisted bundle over the
four-dimensional Minkowski spacetime. The solution describe a non-BPS black
hole rotating in the direction of the extra dimension. The solutions have the
limits to the supersymmetric black hole solutions, a new extreme non-BPS black
hole solutions and a new rotating non-BPS black hole solution with a constant
twisted fiber.Comment: 18 pages, 4 figure
Identification and targeted disruption of the mouse gene encoding ESG1 (PH34/ECAT2/DPPA5)
BACKGROUND: Embryonic stem cell-specific gene (ESG) 1, which encodes a KH-domain containing protein, is specifically expressed in early embryos, germ cells, and embryonic stem (ES) cells. Previous studies identified genomic clones containing the mouse ESG1 gene and five pseudogenes. However, their chromosomal localizations or physiological functions have not been determined. RESULTS: A Blast search of mouse genomic databases failed to locate the ESG1 gene. We identified several bacterial artificial clones containing the mouse ESG1 gene and an additional ESG1-like sequence with a similar gene structure from chromosome 9. The ESG1-like sequence contained a multiple critical mutations, indicating that it was a duplicated pseudogene. The 5' flanking region of the ESG1 gene, but not that of the pseudogene, exhibited strong enhancer and promoter activity in undifferentiated ES cells by luciferase reporter assay. To study the physiological functions of the ESG1 gene, we replaced this sequence in ES cells with a β-geo cassette by homologous recombination. Despite specific expression in early embryos and germ cells, ESG1(-/- )mice developed normally and were fertile. We also generated ESG1(-/- )ES cells both by a second independent homologous recombination and directly from blastocysts derived from heterozygous intercrosses. Northern blot and western blot analyses confirmed the absence of ESG1 in these cells. These ES cells demonstrated normal morphology, proliferation, and differentiation. CONCLUSION: The mouse ESG1 gene, together with a duplicated pseudogene, is located on chromosome 9. Despite its specific expression in pluripotent cells and germ cells, ESG1 is dispensable for self-renewal of ES cells and establishment of germcells
Striosomal opioid receptors
The opioid peptide receptors consist of three major subclasses, namely, μ, δ, and κ (MOR, DOR, and KOR, respectively). They are involved in the regulation of striatal dopamine functions, and increased opioid transmissions are thought to play a compensatory role in altered functions of the basal ganglia in Parkinson's disease (PD). In this study, we used an immunohistochemistry with tyramide signal amplification (TSA) protocols to determine the distributional patterns of opioid receptors in the striosome-matrix systems of the rat striatum. As a most striking feature of striatal opioid anatomy, MORs are highly enriched in the striosomes and subcallosal streak. We also found that DORs are localized in a mosaic pattern in the dorsal striatum (caudate-putamen), with heightened labeling for DOR in the striosomes relative to the matrix compartment. In the 6-hydroxydopamine-lesioned rat model of PD, lesions of the nigrostriatal pathways caused a significant reduction of striatal labeling for both the MOR and DOR in the striosomes, but not in the matrix compartment. Our results suggest that the activities of the striosome and matrix compartments are differentially regulated by the opioid signals involving the MORs and DORs, and that the striosomes may be more responsive to opioid peptides (e.g., enkephalin) than the matrix compartment. Based on a model in which the striosome compartment regulates the striatal activity, we propose a potent compensatory role of striosomal opioid signaling under the conditions of the striatal dopamine depletion that occurs in PD
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