534 research outputs found
Gauss-Bonnet braneworld cosmological effect on relic density of dark matter
In Gauss-Bonnet braneworld cosmology, the Friedmann equation of our
four-dimensional universe on 3-brane is modified in a high energy regime
(Gauss-Bonnet regime), while the standard expansion law is reproduced in low
energies (standard regime). We investigate the Gauss-Bonnet braneworld
cosmological effect on the thermal relic density of cold dark matter when the
freeze-out of the dark matter occurs in the Gaugss-Bonnet regime. We find that
the resultant relic density is considerably reduced when the transition
temperature, which connects the Gauss-Bonnet regime with the standard regime,
is low enough. This result is in sharp contrast with the result previously
obtained in the Randall-Sundrum braneworld cosmology, where the relic density
is enhanced.Comment: 11 pages, 2 figures, new references were added, some typos were
correcte
Evolution of corticosteroid specificity for human, chicken, alligator and frog glucocorticoid receptors
We investigated the evolution of the response of human, chicken, alligator and frog glucocorticoid receptors (GRs) to dexamethasone, cortisol, cortisone, corticosterone, 11-deoxycorticosterone, 11-deoxycortisol and aldosterone. We find significant differences among these vertebrates in the transcriptional activation of their full length GRs by these steroids, indicating that there were changes in the specificity of the GR for steroids during the evolution of terrestrial vertebrates. To begin to study the role of interactions between different domains on the GR in steroid sensitivity and specificity for terrestrial GRs, we investigated transcriptional activation of truncated GRs containing their hinge domain and ligand binding domain (LBD) fused to a GAL4 DNA binding domain (GAL4-DBD). Compared to corresponding full length GRs, transcriptional activation of GAL4-DBD_GR-hinge/LBD constructs required higher steroid concentrations and displayed altered steroid specificity, indicating that interactions between the hinge/LBD and other domains are important in glucocorticoid activation of these terrestrial GRs. (C) 2016 Elsevier Inc. All rights reserved
ANTIBACTERIAL ACTIVITY OF BIFIDOBACTERIA ISOLATED FROM INFANT FAECES
Antibacterial activity of bifidobacteria isolated from Mongolian infant faeces was elucidated on pathogenic intestinal bacteria for the development of a new antibacterial bifidobacteria, the permission for which was granted by the Mongolian Medical Ethics Committee Approval (MMECA). A total of forty-nine single colonies were obtained from 3 samples by using a BL medium enrichment. Among them, 29 isolates had Gram−positive, catalase−negative properties, and maul−like or Y−shaped morphology, and then, 20 Bifidobacterium breve and 9 Bifidobacterium longum strains were detected by the B. breve and B. longum specific primers. Organic acids produced by the isolated bifidobacteria in their cell-free supernatants were quantitatively analyzed by a spectrophotometric absorbance at 340 nm, suggesting that D−lactic, L−lactic, and acetic acids were produced, and the pH of the supernatants was at 3.86−4.55. The isolated bifidobacteria showed antibacterial activity toward Escherichia coli and Salmonella typhimurium as high as that of a standard bifidobacteria, however, lower activity against Staphylococcus aureus. The antibacterial activity was probably due to the production of organic acids
Age-related mitochondrial DNA depletion and the impact on pancreatic beta cell function
Type 2 diabetes is characterised by an age-related decline in insulin secretion. We previously identified a 50% age-related decline in mitochondrial DNA (mtDNA) copy number in isolated human islets. The purpose of this study was to mimic this degree of mtDNA depletion in MIN6 cells to determine whether there is a direct impact on insulin secretion. Transcriptional silencing of mitochondrial transcription factor A, TFAM, decreased mtDNA levels by 40% in MIN6 cells. This level of mtDNA depletion significantly decreased mtDNA gene transcription and translation, resulting in reduced mitochondrial respiratory capacity and ATP production. Glucose-stimulated insulin secretion was impaired following partial mtDNA depletion, but was normalised following treatment with glibenclamide. This confirms that the deficit in the insulin secretory pathway precedes K+ channel closure, indicating that the impact of mtDNA depletion is at the level of mitochondrial respiration. In conclusion, partial mtDNA depletion to a degree comparable to that seen in aged human islets impaired mitochondrial function and directly decreased insulin secretion. Using our model of partial mtDNA depletion following targeted gene silencing of TFAM, we have managed to mimic the degree of mtDNA depletion observed in aged human islets, and have shown how this correlates with impaired insulin secretion. We therefore predict that the age-related mtDNA depletion in human islets is not simply a biomarker of the aging process, but will contribute to the age-related risk of type 2 diabetes
Magnetic Ordering in V-Layers of the Superconducting System of Sr2VFeAsO3
Results of transport, magnetic, thermal, and 75As-NMR measurements are
presented for superconducting Sr2VFeAsO3 with an alternating stack of FeAs and
perovskite-like block layers. Although apparent anomalies in magnetic and
thermal properties have been observed at ~150 K, no anomaly in transport
behaviors has been observed at around the same temperature. These results
indicate that V ions in the Sr2VO3-block layers have localized magnetic moments
and that V-electrons do not contribute to the Fermi surface. The electronic
characteristics of Sr2VFeAsO3 are considered to be common to those of other
superconducting systems with Fe-pnictogen layers.Comment: 4 pages, 4 figures, To appear in JPSJ 79 (2010) 12371
The Multiple Roles of Mps1 in Drosophila Female Meiosis
The Drosophila gene ald encodes the fly ortholog of mps1, a conserved kinetochore-associated protein kinase required for the meiotic and mitotic spindle assembly checkpoints. Using live imaging, we demonstrate that oocytes lacking Ald/Mps1 (hereafter referred to as Ald) protein enter anaphase I immediately upon completing spindle formation, in a fashion that does not allow sufficient time for nonexchange homologs to complete their normal partitioning to opposite half spindles. This observation can explain the heightened sensitivity of nonexchange chromosomes to the meiotic effects of hypomorphic ald alleles. In one of the first studies of the female meiotic kinetochore, we show that Ald localizes to the outer edge of meiotic kinetochores after germinal vesicle breakdown, where it is often observed to be extended well away from the chromosomes. Ald also localizes to numerous filaments throughout the oocyte. These filaments, which are not observed in mitotic cells, also contain the outer kinetochore protein kinase Polo, but not the inner kinetochore proteins Incenp or Aurora-B. These filaments polymerize during early germinal vesicle breakdown, perhaps as a means of storing excess outer kinetochore kinases during early embryonic development
MosAIck: Staging Contemporary AI Performance - Connecting Live Coding, E-Textiles and Movement
This paper introduces our collective work “Patterns in Between Intelligences”, a performance piece that builds an artistic practice between live coding sounds and coding through dance, mediated and shaped through e-textile sensors. This creates a networked system of which both live coded processes and human bodies are part. The paper describes in detail the implementations of technology used in the prototype performance performed at No Bounds Festival in Sheffield UK, October 2022, as well as discussions and concerns the team had related to the use of AI technology on stage. The paper concludes with a narrative reflection on the Sheffield performance, and reflections on it
Study of Ni-doping Effect of Specific Heat and Transport Properties for LaFe1-yNiyAsO0.89F0.11
Specific heats and transport quantities of the LaFe1-yNiyAsO0.89F0.11 system
have been measured, and the results are discussed together with those reported
previously by our group mainly for LaFe1-yCoyAsO0.89F0.11 and
LaFeAsO0.89-xF0.11+x systems. The y dependence of the electronic specific heat
coefficient gamma can basically be understood by using the rigid-band picture,
where Ni ions provide 2 electrons to the host conduction bands and behave as
nonmagnetic impurities. The superconducting transition temperature Tc of
LaFe1-yNiyAsO0.89F0.11 becomes zero, as the carrier density p (=2y+0.11) doped
to LaFeAsO reaches its critical value p_c_ ~0.2. This p_c_ value of ~0.2 is
commonly observed for LaFe1-yCoyAsO0.89F0.11 and LaFeAsO0.89-xF0.11+x systems,
in which the relations p = x+0.11 and p = y+0.11 hold, respectively. As we
pointed out previously, the critical value corresponds to the disappearance of
the hole-Fermi surface. These results indicate that the carrier number solely
determines the Tc value. We have not observed appreciable effects of pair
breaking, which originates from the nonmagnetic impurity scattering of
conduction electrons and strongly suppresses T_c_ values of systems with
sign-reversing of the order parameter over the Fermi surface(s). On the basis
of the results, the so-called s_+-_ symmetry of the order parameter with the
sign-reversing is excluded.Comment: 4 pages, 7 figures, submitted to J. Phys. Soc. Jpn, (modified
version
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