Critical properties of the optical field localization in a three-dimensional percolating system: Theory and experiment

We systematically study the optical field localization in an active three-dimensional (3D) disordered percolating system with light nanoemitters incorporated in percolating clusters. An essential feature of such a hybrid medium is that the clusters are combined into a fractal radiation pattern, in which light is simultaneously emitted and scattered by the disordered structures. Theoretical considerations, based on systematic 3D simulations, reveal nontrivial dynamics in the form of propagation of localized field bunches in the percolating material. We obtain the length of the field localization and dynamical properties of such states as functions of the occupation probability of the disordered clusters. A transition between the dynamical states and narrow point-like fields pinned to the emitters is found. The theoretical analysis of the fractal field properties is followed by an experimental study of the light generation by nanoemitters incorporated in the percolating clusters. The experimental results corroborate theoretical predictions.Comment: 10 pages, 14 figures, to be published Chaos, Solitons & Fractal

In vitro Inhibition of Pancreatic Lipase by Polyphenols: A Kinetic, Fluorescence Spectroscopy and Molecular Docking Study

Svrha je ovog istraživanja bila ispitati molekulsko uklapanje i inhibicijski učinak četiri fenolna spoja pronađena u ljutim papričicama, i to: kavene kiseline, p-kumarne kiseline, kvercetina i kapsaicina, na aktivnost lipaze izolirane iz svinjske gušterače. Najjači inhibicijski učinak imao je kvercetin (IC50=(6.1±2.4) μM), zatim p-kumarna (170.2±20.6) μM) i kavena kiselina (401.5±32.1) μM), dok su kapsaicin i ekstrakt ljute papričice imali iznimno slab učinak. Svi polifenolni spojevi imali su inhibicijski učinak miješanog tipa. Mjerenjem fluorescencije utvrđeno je da su polifenolni spojevi ugasili prirođenu fluorescenciju lipaze izolirane iz gušterače, i to pomoću statičkog mehanizma. Sekvencija Stern-Volmerove konstante bila je: kvercetin, kavena kiselina, te p-kumarna kiselina. Rezultati ispitivanja molekulskih uklapanja pokazali su da se kavena kiselina, kvercetin i p-kumarna kiselina vežu blizu, za razliku od kapsaicina koji se veže daleko od aktivnog mjesta. Vodikove veze i hidrofobne pi-interakcije glavni su načini međusobnog povezivanja polifenolnih spojeva u lipazi izoliranoj iz gušterače.The inhibitory activity and binding characteristics of caffeic acid, p-coumaric acid, quercetin and capsaicin, four phenolic compounds found in hot pepper, against porcine pancreatic lipase activity were studied and compared to hot pepper extract. Quercetin was the strongest inhibitor (IC50=(6.1±2.4) μM), followed by p-coumaric acid ((170.2±20.6) μM) and caffeic acid ((401.5±32.1) μM), while capsaicin and a hot pepper extract had very low inhibitory activity. All polyphenolic compounds showed a mixed-type inhibition. Fluorescence spectroscopy studies showed that polyphenolic compounds had the ability to quench the intrinsic fluorescence of pancreatic lipase by a static mechanism. The sequence of Stern-Volmer constant was quercetin, followed by caffeic and p-coumaric acids. Molecular docking studies showed that caffeic acid, quercetin and p-coumaric acid bound near the active site, while capsaicin bound far away from the active site. Hydrogen bonds and π-stacking hydrophobic interactions are the main pancreatic lipase-polyphenolic compound interactions observed

COP1 destabilizes DELLA proteins in Arabidopsis

DELLA transcriptional regulators are central components in the control of plant growth responses to the environment. This control is considered to be mediated by changes in the metabolism of the hormones gibberellins (GAs), which promote the degradation of DELLAs. However, here we show that warm temperature or shade reduced the stability of a GA-insensitive DELLA allele in Arabidopsis thaliana. Furthermore, the degradation of DELLA induced by the warmth preceded changes in GA levels and depended on the E3 ubiquitin ligase CONSTITUTIVELY PHOTOMORPHOGENIC1 (COP1). COP1 enhanced the degradation of normal and GA-insensitive DELLA alleles when coexpressed in Nicotiana benthamiana. DELLA proteins physically interacted with COP1 in yeast, mammalian, and plant cells. This interaction was enhanced by the COP1 complex partner SUPRESSOR OF phyA-105 1 (SPA1). The level of ubiquitination of DELLA was enhanced by COP1 and COP1 ubiquitinated DELLA proteins in vitro. We propose that DELLAs are destabilized not only by the canonical GA-dependent pathway but also by COP1 and that this control is relevant for growth responses to shade and warm temperature.This work was supported by the Spanish Ministry of Economy, Industry and Competitiveness and Agencia Española de Investigación/Fondo Europeo para el Desarrollo Regional/Unión Europea (grants BIO2016-79133-P to D.A. and BIO2013-46539-R and BIO2016-80551-R to V.R.); the European Union SIGNAT-Research and Innovation Staff Exchange (Grant H2020-MSCA-RISE-2014-644435 to M.A.B., D.A., and J.J.C.); the Argentinian Agencia Nacional de Promoción Científica y Tecnológica (Grant Proyectos de Investigación Científica y Tecnológica-2016-1459 to J.J.C.); Universidad de Buenos Aires (grant 20020170100505BA to J.J.C.); the National Institute of General Medical Sciences of the National Institutes of Health (awards R01GM067837 and R01GM056006 to S.A.K.); the German Research Foundation (DFG) under Germany’s Excellence Strategy/Initiative (Cluster of Excellence on Plant Sciences – Excellence Cluster EXC-2048/1, Project ID 390686111 to M.D.Z.); the International Max Planck Research School of the Max Planck Society; the Universities of Düsseldorf and of Cologne to T.B.; Nordrhein Westfalen Bioeconomy Science Center-FocusLabs CombiCom to N.H. and M.D.Z.; and Ministry of Education, Youth and Sports of the Czech Republic (Project LQ1601 Central European Institute of Technology 2020 to B.B. and M.C.). N.B.-T., E.I., and M.G.-L. were supported by Ministerio de Economía y Competitividad-Formación de Personal Investigador Program fellowships

Medición del nivel de exposición a campos electromagnéticos en ambientes externos en el rango de frecuencias de 100 kHz a 3 GHz en ámbitos de la UNLP y zonas sensibles

La población está expuesta a múltiples fuentes de campos electromagnéticos (CEM) de radiación no ionizante (RNI) en una amplia gama de frecuencias que van más allá de las radiofrecuencias. En las últimas décadas debido a la generación de campos electromagnéticos artificiales de distintas fuentes (antenas de radios de AM, FM, telefonía celular, radares, computadoras, hornos de microondas, equipos médicos, etc.) ha aumentado considerablemente el nivel de exposición a las mismas. El IARC (International Agency for Research on Cancer) en el año 2011 categorizó las RNI en el rango de frecuencias de 30 kHz a 300 GHz como pertenecientes al Grupo 2B (posiblemente carcinogénicas para los humanos). Este informe ha suscitado preocupaciones sobre los posibles riesgos para la salud asociados con los campos electromagnéticos. Objetivo: evaluar y determinar los niveles de exposición a las RNI en ámbitos académicos externos y comparar los resultados obtenidos con la disposición emitida por la Comisión Internacional de Radiación No Ionizante (ICNIRP).Facultad de Ciencias Médica

Evaluación del nivel de exposición a las radiaciones no ionizantes (RNI) en la Facultad de Ciencias Médicas de la UNLP: fase 1

Todos los seres vivos están expuestos a una mezcla compleja de campos electromagnéticos (CEM) en todo el espectro de frecuencias: en la naturaleza, en el hogar y en el trabajo. Los CEM son generados por la corriente eléctrica que circula por los distintos equipos de electromedicina, iluminación, computación y comunicaciones entre otros. Estos campos generan radiaciones no ionizantes (RNI) que no tienen la suficiente energía para romper los enlaces de la última órbita de los átomos, por lo tanto la materia no puede ser ionizada. A raíz de las últimas publicaciones del IARC (International Agency for Research on Cancer) sobre sus posibles efectos carcinogénicos nos motivó a la realización del presente trabajo. Objetivos: evaluar y determinar el nivel de exposición a las RNI en ámbitos de la facultad de Ciencias Médicas de la UNLP.Facultad de Ciencias Médica

Near barrier scattering of 8He on 208Pb

The exotic nucleus 8He is investigated by means of the measurement of the angular distributions of the elastic channel and the 6He and 4He fragment yields produced in the collision with a 208Pb target at two energies around the Coulomb barrier, 16 and 22 MeV. The experiment was performed at the GANIL-SPIRAL facility, with the aim of extracting information about the structure of 8He and the relevant reaction mechanisms. In this contribution, details of the experimental setup and preliminary data on elastic cross sections are reported

A genome-wide association study follow-up suggests a possible role for PPARG in systemic sclerosis susceptibility

Introduction: A recent genome-wide association study (GWAS) comprising a French cohort of systemic sclerosis (SSc) reported several non-HLA single-nucleotide polymorphisms (SNPs) showing a nominal association in the discovery phase. We aimed to identify previously overlooked susceptibility variants by using a follow-up strategy.<p></p> Methods: Sixty-six non-HLA SNPs showing a P value <10-4 in the discovery phase of the French SSc GWAS were analyzed in the first step of this study, performing a meta-analysis that combined data from the two published SSc GWASs. A total of 2,921 SSc patients and 6,963 healthy controls were included in this first phase. Two SNPs, PPARG rs310746 and CHRNA9 rs6832151, were selected for genotyping in the replication cohort (1,068 SSc patients and 6,762 healthy controls) based on the results of the first step. Genotyping was performed by using TaqMan SNP genotyping assays. Results: We observed nominal associations for both PPARG rs310746 (PMH = 1.90 × 10-6, OR, 1.28) and CHRNA9 rs6832151 (PMH = 4.30 × 10-6, OR, 1.17) genetic variants with SSc in the first step of our study. In the replication phase, we observed a trend of association for PPARG rs310746 (P value = 0.066; OR, 1.17). The combined overall Mantel-Haenszel meta-analysis of all the cohorts included in the present study revealed that PPARG rs310746 remained associated with SSc with a nominal non-genome-wide significant P value (PMH = 5.00 × 10-7; OR, 1.25). No evidence of association was observed for CHRNA9 rs6832151 either in the replication phase or in the overall pooled analysis.<p></p> Conclusion: Our results suggest a role of PPARG gene in the development of SSc