6,194 research outputs found
Thermal Pions at Finite Isospin Chemical Potential
The density corrections, in terms of the isospin chemical potential ,
to the mass of the pions are studied in the framework of the SU(2) low energy
effective chiral lagrangian. The pion decay constant is
also analized. As a function of temperature for , the mass remains
quite stable, starting to grow for very high values of , confirming previous
results. However, there are interesting corrections to the mass when both
effects (temperature and chemical potential) are simultaneously present. At
zero temperature the should condensate when . This is not longer valid anymore at finite . The mass of the
acquires also a non trivial dependence on due to the finite
temperature.Comment: 13 pages, 5 figure
Meson - nucleon vertex form factors at finite temperature
In this paper the dependence of meson-nucleon-nucleon vertex form factors is
studied as a function of termperature. The results are obtained starting from a
zero temperature Bonn potential. The temperature dependence of the vertex form
factors and radii is studied in the thermofield dynamics, a real-time operator
formalism of finite temperature field theory. It is anticipated that these
results will have an impact on the study of relativistic heavy-ion collisions
as the critical temperature for the phase transition from hadronic to
quark-gluon system is approached.Comment: 19 pages, Revtex, 11 figures (Ps), 171k
Proteins involved in mitochondrial metabolic functions and fertilization predominate in stallions with better motility
Even in stallions with sperm quality within normal reference ranges at ejaculation, subtle differences in sperm quality exist that in many cases lead to reduced time frames for conservation of the ejaculate and/or reduced fertility. The spermatozoon is a cell highly suitable for proteomics studies, and the use of this technique is allowing rapid advances in the understanding of sperm biology. The aim of the present study was to investigate differences among stallions of variable sperm quality (based on motility and sperm velocities), although all horses had sperm characteristics within normal ranges. The proteome was studied using UHPLC/MS/MS and posterior bioinformatic and enrichment analysis; data are available via ProteomeXchange with identifier PXD025807. Sperm motility, linear motility and circular, straight line and average velocities (VCL, VSL, VAP) were measured using computer assisted sperm analysis (CASA). In stallions showing better percentages of motility, circular and average velocity predominated mitochondrial proteins with roles in the Citric acid cycle, pyruvate metabolism and oxidative phosphorylation. Interestingly, in stallions with better percentages of total motility, sperm proteins were also enriched in proteins within the gene ontology (G0) terms, single fertilization (G0: 0007338), fertilization (G0: 0009566), and zona pellucida receptor complex (GO:0002199). The enrichment of this proteins in samples with better percentages of total motility may offer a molecular explanation for the link between this parameter and fertility. Significance: Proteomic analysis identified a high degree of specificity of stallion sperm proteins with discriminant power for motility, linear motility, and sperm velocities (VCL, VAP and VSL). These findings may represent an interesting outcome in relation to the molecular biology regulating the movement of the spermatozoa, and the biological meaning of the measurements that computer assisted sperm analysis (CASA) provide. Of a total of 903 proteins identified in stallion spermatozoa, 24 were related to the percentage of total motility in the sample; interestingly, gene ontology (G0) analysis revealed that these proteins were enriched in terms like single fertilization and fertilization, providing a molecular link between motility and fertility. Field studies indicate that the percentage of total motility is the CASA derived parameter with the best correlation with fertility in stallions
SpeS: A Novel Superantigen and Its Potential as a Vaccine Adjuvant against Strangles.
Bacterial superantigens (sAgs) are powerful activators of the immune response that trigger unspecific T cell responses accompanied by the release of proinflammatory cytokines. Streptococcus equi (S. equi) and Streptococcus zooepidemicus (S. zooepidemicus) produce sAgs that play an important role in their ability to cause disease. Strangles, caused by S. equi, is one of the most common infectious diseases of horses worldwide. Here, we report the identification of a new sAg of S. zooepidemicus, SpeS, and show that mutation of the putative T cell receptor (TCR)-binding motif (YAY to IAY) abrogated TCR-binding, whilst maintaining interaction with major histocompatibility complex (MHC) class II molecules. The fusion of SpeS and SpeSY39I to six S. equi surface proteins using two different peptide linkers was conducted to determine if MHC class II-binding properties were maintained. Proliferation assays, qPCR and flow cytometry analysis showed that SpeSY39I and its fusion proteins induced less mitogenic activity and interferon gamma expression when compared to SpeS, whilst retaining Antigen-Presenting Cell (APC)-binding properties. Our data suggest that SpeSY39I-surface protein fusions could be used to direct vaccine antigens towards antigen-presenting cells in vivo with the potential to enhance antigen presentation and improve immune responses
Photoionization of Metastable O^+ Ions: Experiment and Theory
Relevant data is available at: http://www.astronomy.ohio-state.edu/~nahar/nahar_radiativeatomicdata/index.htmlHigh-resolution absolute experimental measurements and two independent theoretical calculations were performed for photoionization of O^+ ions from the ^2 P° and ^2 D° metastable levels and from the
^4 S° ground state in the photon energy range 30â35.5 eV. This is believed to be the first comparison of experiment and theory to be reported for photoionization from metastable states of ions. While there is
correspondence between the predicted and measured positions and relative strengths of the resonances, the cross-section magnitudes and fine structure are sensitive to the choice of basis states.The experimental work was supported in part by the DOE Divisions of Chemical Sciences, Geosciences and Biosciences, and Materials Sciences, by the DOE Facilities Initiative, by Nevada DOE/EPSCoR, by CONACyT and DGAPA (Mexico), and by CNPq (Brazil). The theoretical work was supported in part by NSF, by the Ohio Supercomputer Center, by ITAMP/Harvard-Smithsonian, and by EPSRC (UK)
Coulomb excitation of exotic nuclei at the R3B-LAND setup
Exotic Ni isotopes have been measured at the R3B-LAND setup at GSI in
Darmstadt, using Coulomb excitation in inverse kinematics at beam energies
around 500 MeV/u. As the experimental setup allows kinematically complete
measurements, the excitation energy was reconstructed using the invariant mass
method. The GDR and additional low-lying strength have been observed in 68Ni,
the latter exhausting 4.1(1.9)% of the E1 energy-weighted sum rule. Also, the
branching ratio for the non-statistical decay of the excited 68Ni nuclei was
measured and amounts to 24(4)%.Comment: 11 pages, 7 figures. Invited Talk given at the 11th International
Conference on Nucleus-Nucleus Collisions (NN2012), San Antonio, Texas, USA,
May 27-June 1, 2012. To appear in the NN2012 Proceedings in Journal of
Physics: Conference Series (JPCS
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