Aging-associated Alteration in the Cardiac MIF-AMPK Cascade in Response to Ischemic Stress

An important role for a macrophage migration inhibitory factor (MIF)-AMP-activated protein kinase (AMPK) signaling pathway in ameliorating myocardial damage following ischemia/reperfusion has been described. An aging-associated reduction in AMPK activity may be associated with a decline in the ability of cardiac cells to activate the MIF-AMPK cascade, thereby resulting in reduced tolerance to ischemic insults. To test this hypothesis, _in vivo_ regional ischemia was induced by occlusion of the left anterior descending (LAD) coronary artery in young (4-6 months) and aged (24-26 months) mice. The ischemic AMPK activation response was impaired in aged hearts compared to young ones (p<0.01). Notably, cardiac MIF expression in aged hearts was lower than in young hearts (p<0.01). Dual staining data clearly demonstrated larger infarct size in aged hearts following ischemia and reperfusion compared to young hearts (p<0.05). Ischemia-induced AMPK activation in MIF knock out (MIF KO) hearts was blunted, leading to greater contractile dysfunction of MIF KO cardiomyocytes during hypoxia than that of wild type (WT) cardiomyocytes. Finally exogenous recombinant MIF significantly reversed the contractile dysfunction of aged cardiomyocytes in response to hypoxia. We conclude that an aging-associated reduction in ischemic AMPK activation contributes to ischemic intolerance in aged hearts

Deletion of annexin 2 light chain p11 in nociceptors causes deficits in somatosensory coding and pain behavior

The S100 family protein p11 (S100A10, annexin 2 light chain) is involved in the trafficking of the voltage-gated sodium channel Na(V)1.8, TWIK-related acid-sensitive K+ channel (TASK-1), the ligand-gated ion channels acid-sensing ion channel 1a (ASIC1a) and transient receptor potential vanilloid 5/6 (TRPV5/V6), as well as 5-hydroxytryptamine receptor 1B (5-HT1B), a G-protein-coupled receptor. To evaluate the role of p11 in peripheral pain pathways, we generated a loxP-flanked (floxed) p11 mouse and used the Cre-loxP recombinase system to delete p11 exclusively from nociceptive primary sensory neurons in mice. p11-null neurons showed deficits in the expression of NaV1.8, but not of annexin 2. Damage-sensing primary neurons from these animals show a reduced tetrodotoxin-resistant sodium current density, consistent with a loss of membrane-associated NaV1.8. Noxious coding in wide-dynamic-range neurons in the dorsal horn was markedly compromised. Acute pain behavior was attenuated in certain models, but no deficits in inflammatory pain were observed. A significant deficit in neuropathic pain behavior was also apparent in the conditional-null mice. These results confirm an important role for p11 in nociceptor function

Isospin dependence of nucleon effective mass in Dirac Brueckner-Hartree-Fock approach

The isospin dependence of the nucleon effective mass is investigated in the framework of the Dirac Brueckner-Hartree-Fock (DBHF) approach. The definition of nucleon scalar and vector effective masses in the relativistic approach is clarified. Only the vector effective mass is the quantity related to the empirical value extracted from the analysis in the nonrelatiistic shell and optical potentials. In the relativistic mean field theory, where the nucleon scalar and vector potentials are both energy independent, the neutron vector potential is stronger than that of proton in the neutron rich nuclear matter, which produces a smaller neutron vector effective mass than that of proton. It is pointed out that the energy dependence of nucleon potentials has to be considered in the analysis of the isospin dependence of the nucleon effective mass. In the DBHF the neutron vector effective mass is larger than that of proton once the energy dependence of nucleon potentials is considered. The results are consistent with the analysis of phenomenological isospin dependent optical potentials.Comment: 4 pages, 3 Postscript figure

Non-universal gauge bosons Z′Z^{\prime} and lepton flavor-violation tau decays

There are many models beyond the standard model predicting the existence of non-universal gauge bosons $Z^{\prime}$, which can give rise to very rich phenomena. We calculate the contributions of the non-universal gauge bosons $Z^{\prime}$, predicted by topcolor-assisted technicolor (TC2) models and flavor-universal TC2 models, to the lepton flavor-violation tau decays $\tau\to l_{i}\gamma$ and $\tau\to l_{i}l_{j}l_{k}$. We find that the branching ratio $B_{r}(\tau\longrightarrow l_{i}l_{j}l_{k})$ is larger than that of the process $\tau\longrightarrow l_{i}\gamma$ in all of the parameter space. Over a sizable region of the parameter space, we have $B_{r}(\tau\longrightarrow l_{i}l_{j}l_{k})\sim 10^{-8}$, which may be detected in the future experiments.Comment: Final version to appear in Phys. Lett. B. References added and typos correcte

Topcolor assisted technicolor models and muon anomalous magnetic moment

We discuss and estimate the contributions of the new particles predicted by topcolor assisted technicolor(TC2) models to the muon anomalous magnetic moment $a_{\mu}$. Our results show that the contributions of Pseudo Goldstone bosons are very small which can be safely ignored. The main contributions come from the ETC gauge boson $x_{\mu}$ and topcolor gauge boson $Z^{\prime}$. If we demand that the mass of $Z^{\prime}$ is consistent with other experimental constrains, its contributions are smaller than that of $x_{\mu}$. With reasonable values of the parameters in TC2 models, the observed BNL results for $a_{\mu}$ could be explained.Comment: latex file, 11 pages, several figures and references adde

Muon anomalous magnetic moment in technicolor models

Contributions to the muon anomalous magnetic moment are evaluated in the technicolor model with scalars and topcolor assisted technicolor model. In the technicolor model with scalars, the additional contributions come from the loops of scalars, which were found sizable only for a very large $f/f^{'}$ disfavored by the experiment of $b\to s\gamma$. The topcolor effect is also found to be large only for an unnaturally large $\tan\theta'$, and thus the previously evaluated loop effects of extended technicolor bosons, suppressed by $m_{\mu}^2/M_{ETC}^2$, must be resorted to account for the E821 experiment. So, if the E821 experiment result persists, it would be a challenge to technicolor models.Comment: refs and comments adde

Generalised Compositional Theories and Diagrammatic Reasoning

This chapter provides an introduction to the use of diagrammatic language, or perhaps more accurately, diagrammatic calculus, in quantum information and quantum foundations. We illustrate the use of diagrammatic calculus in one particular case, namely the study of complementarity and non-locality, two fundamental concepts of quantum theory whose relationship we explore in later part of this chapter. The diagrammatic calculus that we are concerned with here is not merely an illustrative tool, but it has both (i) a conceptual physical backbone, which allows it to act as a foundation for diverse physical theories, and (ii) a genuine mathematical underpinning, permitting one to relate it to standard mathematical structures.Comment: To appear as a Springer book chapter chapter, edited by G. Chirabella, R. Spekken

Enhancement of Radiatively Induced Magnetic Moment Form-Factors of Muon: an Effective Lagrangian Approach

Using an effective lagrangian approach, we identify a class of models in which the loop-induced magnetic moment form-factors of muon are enhanced by possibly large factors (\Lambda^2_F/\Lambda^2)(m_\tau/m_\mu)\ln(m_\tau^2/\Lambda^2) or (\Lambda^2_F/\Lambda^2)\ln(m_\mu^2/\Lambda^2), where \Lambda is the scale of new physics and \Lambda_F is the Fermi scale. These follow from left- and right-chirality mixing dimension-8 operators which for relatively small \Lambda, as required to explain the new (g_\mu-2) measurement, dominate over dimension-6 operators. Thus significant enhancement of new physics contributions to (g_\mu-2) and, in the presence of intergenerational couplings, also to the \mu\to e\gamma decay rate is possible. We discuss the compatibility of the (g_\mu-2) and \mu\to e\gamma experimental data in this case and comment on the enhancement of the electron anomalous magnetic moment. An explicit model is presented to illustrate the general results.Comment: Discussion on the enhancement of electron anomalous magnetic moment included. New references adde

Assessing Professionalism: A theoretical framework for defining clinical rotation assessment criteria

Although widely accepted as an important graduate competence, professionalism is a challenging outcome to define and assess. Clinical rotations provide an excellent opportunity to develop student professionalism through the use of experiential learning and effective feedback, but without appropriate theoretical frameworks, clinical teachers may find it difficult to identify appropriate learning outcomes. The adage “I know it when I see it” is unhelpful in providing feedback and guidance for student improvement, and criteria that are more specifically defined would help students direct their own development. This study sought first to identify how clinical faculty in one institution currently assess professionalism, using retrospective analysis of material obtained in undergraduate teaching and faculty development sessions. Subsequently, a faculty workshop was held in which a round-table type discussion sought to develop these ideas and identify how professionalism assessment could be improved. The output of this session was a theoretical framework for teaching and assessing professionalism, providing example assessment criteria and ideas for clinical teaching. This includes categories such as client and colleague interaction, respect and trust, recognition of limitations, and understanding of different professional identities. Each category includes detailed descriptions of the knowledge, skills, and behaviors expected of students in these areas. The criteria were determined by engaging faculty in the development of the framework, and therefore they should represent a focused development of criteria already used to assess professionalism, and not a novel and unfamiliar set of assessment guidelines. The faculty-led nature of this framework is expected to facilitate implementation in clinical teaching