Greater diversity than previously thought of chromaffin cell Ca2+ channels, derived from mRNA identification studies

AbstractUsing reverse transcription followed by PCR amplification (RT-PCR), we have identified multiple messenger RNAs encoding for the neuronal pore-forming Ca2+ channel subunits α1A (P/Q channel), α1B (N channel), α1D (neuronal/endocrine L channel), α1E (R channel), α1G-H (T channel) and α1S (skeletal muscle L channel) in bovine chromaffin cells. mRNAs for the auxiliary β2, β3, β4, α2/δ and γ2 subunits were also identified. In agreement with these molecular data, perforated patch-clamp recordings of whole-cell Ca2+ currents reveal the existence of functional R-type Ca2+ channels in these cells that were previously undetected with other techniques. Our results provide a molecular frame for a much wider functional diversity of Ca2+ channels in chromaffin cells than that previously established using pharmacological and electrophysiological approaches

Comments on the Instanton Size Distribution

By studying the non-linear effects of overlapping instanton pairs we address difficulties in the identification of instanton distributions when the average instanton size is comparable to the average distance. For the exact charge two solution, we study how its parametrisation relates to a description in terms of individual instantons. There exist two dual sets of parameters describing the same charge two instanton solution. This duality implies the existence of a minimal separation between two instantons. Conventionally used lattice instanton finder algorithms based on the assumption of diluteness tend to underestimate instanton sizes. Finally we numerically confirm this for realistic parameters of the instanton liquid. The effect is enhanced by parallel orientation in group space.Comment: LaTeX, 15 pages, 3 figure

Transition from Diffusive to Localized Regimes in Surface Corrugated Optical Waveguides

Exact calculations of the transmittance of surface corrugated optical waveguides are presented. The elastic scattering of diffuse light or other electromagnetic waves from a rough surface induces a diffusive transport along the waveguide axis. As the length of the corrugated part of the waveguide increases, a transition from the diffusive to the localized regime is observed. This involves an analogy with electron conduction in nanowires, and hence, a concept analogous to that of ``resistance'' can be introduced. We show an oscillatory behavior of both the elastic mean free path and the localization length versus the wavelength.Comment: 3 pages, REVTEX, 3 PS figure

On the Distributional Fourier Duality and Its Applications

AbstractSampling theorems for bandlimited functions or distributions are obtained by exploiting the topological isomorphism between the space E′(R) of distributions of compact support on R and the Paley–Wiener spacePWof entire functions satisfying an estimate of the form |f(z)|≤A(1+|z|)NeB|Imz|for some constantsA,B,N≥0. We obtain sampling theorems forfinPWby expanding its Fourier transformTin a series converging in the topology of E′(R) and whose coefficients are samples taken fromf. By Fourier duality, we obtain a sampling theorem forfin the spacePW. These sampling expansions converge, in fact, uniformly on compact sets of C, since convergence in the topology ofPWimplies uniform convergence on compact sets of C. This procedure allows us to recover previous sampling theorems in a unified way. We also present further expansions of Paley–Wiener functions obtained by expanding their Fourier transform as a series involving Legendre or Hermite polynomials

Characterization of surface layers in Zn-diffused LiNbO3 waveguides by heavy ion elastic recoil detection

Copyright (2002) American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Applied Physics Letters 81.11 (2002): 1981-1983 and may be found at http://apl.aip.org

Non-Linear Canonical Transformations in Classical and Quantum Mechanics

$p$-Mechanics is a consistent physical theory which describes both classical and quantum mechanics simultaneously through the representation theory of the Heisenberg group. In this paper we describe how non-linear canonical transformations affect $p$-mechanical observables and states. Using this we show how canonical transformations change a quantum mechanical system. We seek an operator on the set of $p$-mechanical observables which corresponds to the classical canonical transformation. In order to do this we derive a set of integral equations which when solved will give us the coherent state expansion of this operator. The motivation for these integral equations comes from the work of Moshinsky and a variety of collaborators. We consider a number of examples and discuss the use of these equations for non-bijective transformations.Comment: The paper has been improved in light of a referee's report. The paper will appear in the Journal of Mathematical Physics. 24 pages, no figure

Growth and optical characterization of indirect-gap AlxGa1−xAs alloys

Nonintentionally doped AlxGa1−xAs layers with 0.38 x 0.84 were grown on (100) GaAs substrates by liquid phase epitaxy (LPE) under near-equilibrium conditions. The crystalline quality of the samples was studied by photoluminescence at 2 K and room temperature Raman spectroscopy. The peculiar behavior in the photoluminescence intensities of the indirect bound exciton line and the donor–acceptor pair transition is explained from the evolution of the silicon donor binding energy according to the aluminum composition. It was also possible to observe the excitonic transition corresponding to the AlxGa1−xAs/GaAs interface, despite the disorder and other factors which are normally involved when growing high-aluminum-content layers by this technique. Furthermore, Raman measurements show the quadratic variations of longitudinal optical phonon frequencies with aluminum concentration in good agreement with previous experimental results. In this work we show that high quality indirect-gap AlxGa1−xAs samples can be grown by LPE under near-equilibrium [email protected]

Fisiopatología de la enfermedad COVID-19

La enfermedad por coronavirus es una infección respiratoria causada por el virus SARS- CoV 2, el cual genera una cascada de eventos sistémicos, afectando diferentes órganos y tejidos. El entendimiento de la fisiopatologı́a del COVID-19 es indispensable no solo al momento de brindar tratamiento a los pacientes, sino que también para comprender las causas de las complicaciones que presentan un número importante de pacientes recuperados. El objetivo de este trabajo es presentar una revisión actualizada de los efectos de la infección en diferentes órganos y sistemas principales que sea de utilidad como material de referencia para profesionales y estudiantes de la salud. Para ello se realizó una búsqueda bibliográfica en los portales PubMED, Scielo, Google Scholar, Cochrane y Springer Link, ası́ como en las bases de repositorios cientı́ficos pre- publicación bioRxiv (“bioarchives”) y medRxiv (“med-archives”) y sobre un total de cerca de 200 mil artı́culos, se seleccionaron 100 artı́culos para esta revisión en base a su relevancia o sugerencias de parte de profesionales especializados