Diminished fraction of blockable ATP-sensitive K+ channels in islets transplanted into diabetic mice

The reasons for the poor outcome of islet transplantation in diabetic patients are not well known; a better understanding of the pathophysiology of transplanted islets is needed. To study the mechanism coupling secretagogue stimuli with insulin release in transplanted islets, we determined the effects of glucose, tolbutamide, and carbamylcholine on the beta-cell membrane potential and cytosolic calcium concentrations ([Ca2+]i) of islets syngeneically transplanted into normal and streptozocin-induced diabetic mice. In both groups, normoglycemia was maintained after transplantation. Islets transplanted into normal recipients showed similar changes in beta-cell membrane potential and [Ca2+]i oscillations to those in control islets. In contrast, when islets were transplanted into diabetic mice, bursts of electrical activity were triggered at lower glucose concentrations (5.6 mmol/l) than in control islets (11 mmol/l), and maximal electrical activity was achieved at lower glucose concentrations (11 mmol/l) than in control islets (22 mmol/l). When membrane potential was plotted as a function of glucose concentration, the dose-response curve was shifted to the left. Compared with control islets, glucose-induced [Ca2+]i oscillations were broader in duration (22.3 +/- 0.6 s vs. 118.1 +/- 12.6 s; P < 0.01) and higher in amplitude (135 +/- 36 nmol/l vs. 352 +/- 36 nmol/l; P < 0.01). Glucose supersensitivity was attributed to a resting decrease in the fraction of blockable ATP-sensitive K+ (K+(ATP)) channels in transplanted islets that maintained normoglycemia with a limited beta-cell mass

Unitarized chiral perturbation theory of hadrons

An exposition is made of recent developments using techniques of unitary chiral perturbation theory, $U \chi P T$, which allows one to extend predictions using chiral Lagrangians to higher energies than ordinary chiral perturbation theory, including the region of low lying mesonic and baryonic resonances, some of which are dynamically generated in the approach. Results for meson meson scattering, pion and kaon form factors and meson baryon scattering are shown. Applications are done for nuclear problems showing the results for the kaon and eta selfenergies, phi renormalization in a nuclear medium and $\sigma$ renormalization in the medium, comparing results with recent experiments.Comment: Talk at PANIC2002 Conference, Osaka, October 200

Recent progress on the chiral unitary approach to meson meson and meson baryon interactions

We report on recent progress on the chiral unitary approach, analogous to the effective range expansion in Quantum Mechanics, which is shown to have a much larger convergence radius than ordinary chiral perturbation theory, allowing one to reproduce data for meson meson interaction up to 1.2 GeV. Applications to physical processes so far unsuited for a standard chiral perturbative approach are presented. Results for the extension of these ideas to the meson baryon sector are discussed, together with applications to kaons in a nuclear medium and $K^-$ atoms.Comment: Contribution to the KEK Tanashi Symposium on Physics of Hadrons and Nuclei, Tokyo, December 1998, 10 pages, 3 postscript figures. To be published as a special issue of Nuclear Physics

The σ\sigma meson in a nuclear medium through two pion photoproduction

We present theoretical results for $(\gamma, \pi^0 \pi^0)$ production on nucleons and nuclei in the kinematical region where the scalar isoscalar $\pi \pi$ amplitude is influenced by the $\sigma$ pole. The final state interaction of the pions modified by the nuclear medium produces a spectacular shift of strength of the two pion invariant mass distribution induced by the moving of the $\sigma$ pole to lower masses and widths as the nuclear density increases.Comment: 14 pages, 7 figure

Interactive technologies for preschool game-based instruction: Experiences and future challenges

This is the author’s version of a work that was accepted for publication in Entertainment Computing. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Entertainment Computing, vol. 17 (2016). DOI 10.1016/j.entcom.2016.07.001.[EN] According to current kindergarten curricula, game play is an important basis for children development and it is the main driving force when designing educational activities during early childhood. This paper presents a review of the current state of the art of game technologies that support pre-kindergarten and kindergarten children development. Moreover, the most emergent technologies for developing educational games for preschool children are identified and a set of future challenges are discussed. The main goal of this work is to review the state of the art in interactive technologies which will help educators, game designers and Human-Computer Interaction (HCI) experts in the area of game-based kindergarten instruction. 2016 Elsevier B.V. All rights reserved.This work received financial support from Spanish Ministry of Economy and Competitiveness and funded by the European Development Regional Fund (EDRF-FEDER) with the project TIN2014-60077-R (SUPEREMOS). This work is also supported by a predoctoral fellowship within the FPU program from the Spanish Ministry of Education, Culture and Sports to V. Nacher (FPU14/00136) and from GVA (ACIF/2014/214) to F. Garcia-Sanjuan.Nácher-Soler, VE.; García Sanjuan, F.; Jaén Martínez, FJ. (2016). Interactive technologies for preschool game-based instruction: Experiences and future challenges. Entertainment Computing. 17:19-29. https://doi.org/10.1016/j.entcom.2016.07.001S19291

The role of Delta(1700) excitation and rho production in double pion photoproduction

Recent information on invariant mass distributions of the $\gamma p\to\pi^+\pi^0 n$ reaction, where previous theoretical models had shown deficiencies, have made more evident the need for new mechanisms, so far neglected or inaccurately included. We have updated a previous model to include new necessary mechanisms. We find that the production of the $\rho$ meson, and the $\Delta(1700)$ excitation, through interference with the dominant terms, are important mechanisms that solve the puzzle of the $\gamma p\to\pi^+\pi^0 n$ reaction without spoiling the early agreement with the $\gamma p\to\pi^+\pi^- p$ and $\gamma p\to\pi^0\pi^0 p$ reactions.Comment: 39 pages, 13 figures (ps files). Final version. To be published in Nucl. Phys.