Spatial fluctuations in an optical parametric oscillator below threshold with an intracavity photonic crystal

We show how to control spatial quantum correlations in a multimode degenerate optical parametric oscillator type I below threshold by introducing a spatially inhomogeneous medium, such as a photonic crystal, in the plane perpendicular to light propagation. We obtain the analytical expressions for all the correlations in terms of the relevant parameters of the problem and study the number of photons, entanglement, squeezing, and twin beams. Considering different regimes and configurations we show the possibility to tune the instability thresholds as well as the quantumness of correlations by breaking the translational invariance of the system through a photonic crystal modulation.Comment: 12 pages, 7 figure

Analytic theory of correlation energy and spin polarization in the 2D electron gas

We present an analytic theory of the pair distribution function and the ground-state energy in a two-dimensional (2D) electron gas with an arbitrary degree of spin polarization. Our approach involves the solution of a zero-energy scattering Schr\"odinger equation with an effective potential which includes a Fermi term from exchange and kinetic energy and a Bose-like term from Jastrow-Feenberg correlations. The form of the latter is assessed from an analysis of data on a 2D gas of charged bosons. We obtain excellent agreement with data from quantum Monte Carlo studies of the 2D electron gas. In particular, our results for the correlation energy show a quantum phase transition occurring at coupling strength $r_s\approx 24$ from the paramagnetic to the fully spin-polarized fluid.Comment: 9 pages, 4 figure

The permeation mechanism of organic cations through a CNG mimic channel

Several channels, ranging from TRP receptors to Gap junctions, allow the exchange of small organic solute across cell membrane. However, very little is known about the molecular mechanism of their permeation. Cyclic Nucleotide Gated (CNG) channels, despite their homology with K+channels and in contrast with them, allow the passage of larger methylated and ethylated ammonium ions like dimethylammonium (DMA) and ethylammonium (EA). We combined electrophysiology and molecular dynamics simulations to examine how DMA interacts with the pore and permeates through it. Due to the presence of hydrophobic groups, DMA enters easily in the channel and, unlike the alkali cations, does not need to cross any barrier. We also show that while the crystal structure is consistent with the presence of a single DMA ion at full occupancy, the channel is able to conduct a sizable current of DMA ions only when two ions are present inside the channel. Moreover, the second DMA ion dramatically changes the free energy landscape, destabilizing the crystallographic binding site and lowering by almost 25 kJ/mol the binding affinity between DMA and the channel. Based on the results of the simulation the experimental electron density maps can be re-interpreted with the presence of a second ion at lower occupancy. In this mechanism the flexibility of the channel plays a key role, extending the classical multi-ion permeation paradigm in which conductance is enhanced by the plain interaction between the ions

C-Terminal Domain of the Human Zinc Transporter hZnT8 Is Structurally Indistinguishable from Its Disease Risk Variant (R325W)

The human zinc transporter 8 (hZnT8) plays important roles in the storage of insulin in the secretory vesicles of pancreatic β cells. hZnT8 consists of a transmembrane domain, with its N- and C-termini protruding into the cytoplasm. Interestingly, the exchange of arginine to tryptophan at position 325 in the C-terminal domain (CTD) increases the risk of developing type 2 diabetes mellitus (T2D). In the present study, the CTDs of hZnT8 (the wild-type (WT) and its disease risk variant (R325W)) were expressed, purified, and characterized in their native forms by biophysical techniques. The data reveal that the CTDs form tetramers which are stabilized by zinc binding, and exhibit negligible differences in their secondary structure content and zinc-binding affinities in solution. These findings provide the basis for conducting further structural studies aimed at unravelling the molecular mechanism underlying the increased susceptibility to develop T2D, which is modulated by the disease risk variant

Unisolvency for Multivariate Polynomial Interpolation in Coatmèlec Configurations of Nodes

A new and straightforward proof of the unisolvability of the problem of multivariate polynomial interpolation based on Coatmèlec configurations of nodes, a class of properly posed set of nodes defined by hyperplanes, is presented. The proof generalizes a previous one for the bivariate case and is based on a recursive reduction of the problem to simpler ones following the so-called Radon–Bézout process.The authors thank to Drs. Mariano Gasca and Juan I. Ramos for pointing us some references and for their useful comments which have greatly improved the presentation. The authors also thank a reviewer for pointing out a mistake in the original Proof of Lemma 5. The research reported in this paper was partially supported by Project MTM2010-19969 from the Ministerio de Ciencia e Innovacion of Spain and Grant PAID-06-09-2734 from the Universidad Politecnica de Valencia. M. A. G. M. acknowledges support from the Spanish Ministry of Science and Education (MEC), Fulbright Commission, and FECYT.García March, MÁ.; Gimenez Palomares, F.; Villatoro, FR.; Pérez Quiles, MJ.; Fernández De Córdoba Castellá, PJ. (2011). Unisolvency for Multivariate Polynomial Interpolation in Coatmèlec Configurations of Nodes. Applied Mathematics and Computation. 217(18):7427-7431. https://doi.org/10.1016/j.amc.2011.02.034S742774312171

Diez años de atención farmacéutica en España: explorando la realidad

Este trabajo pretende valorar el impacto, después de 10 años, de la implementación de la atención farmacéutica (AF) en la farmacia comunitaria. La investigación se realizó en tres regiones de España, escogidas por representar la variedad del país; registra la prevalencia de la AF practicada por los farmacéuticos comunitarios y explora el impacto que esa implementación ha tenido en las expectativas y actuaciones de pacientes y médicosde atención primaria. Se comienza analizando las diferencias en el número de farmacéuticos que practican AF entre las tres regiones y sus razones: localización, experiencia profesional y motivación. A continuación, se utilizan dos métodos para valorar el impacto de esa implementación en esas tres regiones. En primer lugar, se realizan grupos focales con pacientes que han recibido y que no han recibido AF, valorando el conocimiento del servicio de AF, las expectativas acerca de la AF (incluida su principal demanda) y la satisfacción con la AF recibida. En segundo lugar, se realizaron entrevistas a médicos de familia de cada región, en las áreas donde trabajaban farmacéuticos que practicaban AF, para evaluar la comprensión de la AF, la opinión sobre los farmacéuticos como profesionales sanitarios, la comunicación con ellos y la visión de sus competencias en la atención a los pacientes. Finalmente, se realizaron entrevistas a los farmacéuticos que ofrecen AF para conocer sus estrategias, con el fin de comunicar sus nuevas funciones a los pacientes y a los médicos de familia

Diez años de atención farmacéutica en España: explorando la realidad

Este trabajo pretende valorar el impacto, después de 10 años, de la implementación de la atención farmacéutica (AF) en la farmacia comunitaria. La investigación se realizó en tres regiones de España, escogidas por representar la variedad del país; registra la prevalencia de la AF practicada por los farmacéuticos comunitarios y explora el impacto que esa implementación ha tenido en las expectativas y actuaciones de pacientes y médicosde atención primaria. Se comienza analizando las diferencias en el número de farmacéuticos que practican AF entre las tres regiones y sus razones: localización, experiencia profesional y motivación. A continuación, se utilizan dos métodos para valorar el impacto de esa implementación en esas tres regiones. En primer lugar, se realizan grupos focales con pacientes que han recibido y que no han recibido AF, valorando el conocimiento del servicio de AF, las expectativas acerca de la AF (incluida su principal demanda) y la satisfacción con la AF recibida. En segundo lugar, se realizaron entrevistas a médicos de familia de cada región, en las áreas donde trabajaban farmacéuticos que practicaban AF, para evaluar la comprensión de la AF, la opinión sobre los farmacéuticos como profesionales sanitarios, la comunicación con ellos y la visión de sus competencias en la atención a los pacientes. Finalmente, se realizaron entrevistas a los farmacéuticos que ofrecen AF para conocer sus estrategias, con el fin de comunicar sus nuevas funciones a los pacientes y a los médicos de familia

Semiclassical theory for spatial density oscillations in fermionic systems

We investigate the particle and kinetic-energy densities for a system of $N$ fermions bound in a local (mean-field) potential V(\bfr). We generalize a recently developed semiclassical theory [J. Roccia and M. Brack, Phys. Rev.\ Lett. {\bf 100}, 200408 (2008)], in which the densities are calculated in terms of the closed orbits of the corresponding classical system, to $D>1$ dimensions. We regularize the semiclassical results $(i)$ for the U(1) symmetry breaking occurring for spherical systems at $r=0$ and $(ii)$ near the classical turning points where the Friedel oscillations are predominant and well reproduced by the shortest orbit going from $r$ to the closest turning point and back. For systems with spherical symmetry, we show that there exist two types of oscillations which can be attributed to radial and non-radial orbits, respectively. The semiclassical theory is tested against exact quantum-mechanical calculations for a variety of model potentials. We find a very good overall numerical agreement between semiclassical and exact numerical densities even for moderate particle numbers $N$. Using a "local virial theorem", shown to be valid (except for a small region around the classical turning points) for arbitrary local potentials, we can prove that the Thomas-Fermi functional $\tau_{\text{TF}}[\rho]$ reproduces the oscillations in the quantum-mechanical densities to first order in the oscillating parts.Comment: LaTeX, 22pp, 15 figs, 1 table, to be published in Phys. Rev.

Microbiological Characterization of the Biofilms Colonizing Bioplastics in Natural Marine Conditions: A Comparison between PHBV and PLA

Biodegradable polymers offer a potential solution to marine pollution caused by plastic waste. The marine biofilms that formed on the surfaces of poly(lactide acid) (PLA) and poly(3- hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) were studied. Bioplastics were exposed for 6 months to marine conditions in the Mediterranean Sea, and the biofilms that formed on their surfaces were assessed. The presence of specific PLA and PHBV degraders was also studied. PHBV showed extensive areas with microbial accumulations and this led to higher microbial surface densities than PLA (4.75 vs. 5.16 log CFU/cm2 ). Both polymers’ surfaces showed a wide variety of microbial structures, including bacteria, fungi, unicellular algae and choanoflagellates. A high bacterial diversity was observed, with differences between the two polymers, particularly at the phylum level, with over 70% of bacteria affiliated to three phyla. Differences in metagenome functions were also detected, revealing a higher presence of proteins involved in PHBV biodegradation in PHBV biofilms. Four bacterial isolates belonging to the Proteobacteria class were identified as PHBV degraders, demonstrating the presence of species involved in the biodegradation of this polymer in seawater. No PLA degraders were detected, confirming its low biodegradability in marine environments. This was a pilot study to establish a baseline for further studies aimed at comprehending the marine biodegradation of biopolymers

GATA-targeted compounds modulate cardiac subtype cell differentiation in dual reporter stem cell line

BackgroundPharmacological modulation of cell fate decisions and developmental gene regulatory networks holds promise for the treatment of heart failure. Compounds that target tissue-specific transcription factors could overcome non-specific effects of small molecules and lead to the regeneration of heart muscle following myocardial infarction. Due to cellular heterogeneity in the heart, the activation of gene programs representing specific atrial and ventricular cardiomyocyte subtypes would be highly desirable. Chemical compounds that modulate atrial and ventricular cell fate could be used to improve subtype-specific differentiation of endogenous or exogenously delivered progenitor cells in order to promote cardiac regeneration.MethodsTranscription factor GATA4-targeted compounds that have previously shown in vivo efficacy in cardiac injury models were tested for stage-specific activation of atrial and ventricular reporter genes in differentiating pluripotent stem cells using a dual reporter assay. Chemically induced gene expression changes were characterized by qRT-PCR, global run-on sequencing (GRO-seq) and immunoblotting, and the network of cooperative proteins of GATA4 and NKX2-5 were further explored by the examination of the GATA4 and NKX2-5 interactome by BioID. Reporter gene assays were conducted to examine combinatorial effects of GATA-targeted compounds and bromodomain and extraterminal domain (BET) inhibition on chamber-specific gene expression.ResultsGATA4-targeted compounds 3i-1000 and 3i-1103 were identified as differential modulators of atrial and ventricular gene expression. More detailed structure-function analysis revealed a distinct subclass of GATA4/NKX2-5 inhibitory compounds with an acetyl lysine-like domain that contributed to ventricular cells (%Myl2-eGFP+). Additionally, BioID analysis indicated broad interaction between GATA4 and BET family of proteins, such as BRD4. This indicated the involvement of epigenetic modulators in the regulation of GATA-dependent transcription. In this line, reporter gene assays with combinatorial treatment of 3i-1000 and the BET bromodomain inhibitor (+)-JQ1 demonstrated the cooperative role of GATA4 and BRD4 in the modulation of chamber-specific cardiac gene expression.ConclusionsCollectively, these results indicate the potential for therapeutic alteration of cell fate decisions and pathological gene regulatory networks by GATA4-targeted compounds modulating chamber-specific transcriptional programs in multipotent cardiac progenitor cells and cardiomyocytes. The compound scaffolds described within this study could be used to develop regenerative strategies for myocardial regeneration.Peer reviewe