Ultra-Broadband Directional Couplers Using Microstrip with Dielectric Overlay in Millimeter-Wave Band

Nowadays, millimeter-wave systems are being a key factor to develop wide band applications. In this paper, a directional coupler in millimeter-wave band using dielectric overlay is presented. This leads us to technology aspects, in directional coupler design, are key points to achieve the proper response of the circuit. The coupler proposed in this paper covers the 15-45 GHz band and its response has 15-dB coupling-level, 1-dB coupling-ripple and a reflection coefficient better than 10 dB

Charge control in laterally coupled double quantum dots

We investigate the electronic and optical properties of InAs double quantum dots grown on GaAs (001) and laterally aligned along the [110] crystal direction. The emission spectrum has been investigated as a function of a lateral electric field applied along the quantum dot pair mutual axis. The number of confined electrons can be controlled with the external bias leading to sharp energy shifts which we use to identify the emission from neutral and charged exciton complexes. Quantum tunnelling of these electrons is proposed to explain the reversed ordering of the trion emission lines as compared to that of excitons in our system.Comment: 4 pages, 4 figures submitted to PRB Rapid Com

Assessment of the antioxidant properties of tomato extracts: A synergistic approach using in vitro chemical tests and cell-based assays

The aim of this research was to assess the total antioxidant activity (TAA) of lipophilic (Lextr) and hydrophilic (Hextr) tomato extracts using in vitro chemical tests and cell-based assays, focusing on possible synergistic actions between tomato antioxidants. Both Hextr and Lextr were HPLC analysed for their carotenoids, phenolic compounds, and ascorbic acid contents. For the evaluation of TAA, extracts were assayed alone or in combination using in vitro chemical tests (TEAC, FRAP) and cell-based (CAA) assays using human hepatoma (HepG2) and human histiocytic lymphoma (U937) cells. The only carotenoid detected in Lextr was lycopene, while a mixture of phenolic compounds (chlorogenic acid, caffeic acid, and rutin) was identified in Hextr. Ascorbic acid was not found either in Hextr or in Lextr. Upon extract combination (1:1, v/v), the FRAP assay revealed additive action between Lextr and Hextr, whilst a slight synergistic action was observed in TAA as measured by the TEAC assay. Synergistic action was better revealed when TAA was analysed using either U937 or HepG2 cells. This could be explained by the presence of a multiphase media (cell membrane and extra- and intracellular media) that might facilitate the distribution and interaction of antioxidants with different polarities and different mechanisms of action

Detección específica de Arcobacter Butzleri en carne de pollo mediante una técnica de PCR

En este trabajo se describe el desarrollo de una técnica de PCR para la detección específica de Arcobacter butzleri en carne fresca de pollo empleando cebadores específicos de especie diseñados en gen 16S ARN ribosómico. Los cebadores seleccionados amplifican un fragmento de 195 pb en A. butzleri, sin producir señal de amplificación en otras especies de Arcobacter, Campylobacter, Helicobacter, ni en otros microorganismos presentes en los alimentos. La técnica de PCR se ha aplicado al análisis de 42 muestras comerciales de carne fresca de pollo adquiridas en diversos comercios minoristas. Tras un pre enriquecimiento selectivo durante 18 h a 30ºC, A. butzleri se detectó en un 85,7% de las muestras analizadas. Se observó una total concordancia entre los resultados obtenidos por PCR y el método convencional de recuento en placas de agar selectivo.A PCR technique was developed for the specific detection of Arcobacter butzleri in fresh chicken meat using species-specific primers designed on the 16S ribosomal ARN gene. The selected primers amplify a 195 bp fragment from A. butzleri whereas no PCR product is generated for other Arcobacter, Campylobacter, Helicobacter species, and other food bacteria. The PCR technique was used to screen 42 retail-purchased chicken samples for the presence of A. butzleri. Following a selective enrichment for 18 h at 30ºC, A butzleri was detected in 85.7% of the analyzed samples, showing a total concordance between the PCR results and the conventional selective plating method

Growth of Low-Density Vertical Quantum Dot Molecules with Control in Energy Emission

In this work, we present results on the formation of vertical molecule structures formed by two vertically aligned InAs quantum dots (QD) in which a deliberate control of energy emission is achieved. The emission energy of the first layer of QD forming the molecule can be tuned by the deposition of controlled amounts of InAs at a nanohole template formed by GaAs droplet epitaxy. The QD of the second layer are formed directly on top of the buried ones by a strain-driven process. In this way, either symmetric or asymmetric vertically coupled structures can be obtained. As a characteristic when using a droplet epitaxy patterning process, the density of quantum dot molecules finally obtained is low enough (2 × 108 cm−2) to permit their integration as active elements in advanced photonic devices where spectroscopic studies at the single nanostructure level are required

Las redes inalámbricas de área local ("Wi-Fi") en la FCC y el CNAF

En los últimos años, las Redes Inalámbricas de Área Local (WLAN, Wireless Local Área Networks) basadas en el estándar IEEE (802.11 [1] y sus derivados ñan conseguido unos altos niveles de implantación y desbordar el ámbito de aplicaciones y servicios para los que fueron inicialmente concebidas. De hecho, que se ñan convertido en un fenómeno tecnológico

Diferenciación de carnes de jabalí europeo (Sus scrofa scrofa) y cerdo doméstico (Sus scrofa domestica) mediante el análisis por PCR de la región mitocondrial D-loop y el gen nuclear MC1R

En este trabajo se describe la diferenciación de carnes procedentes de jabalí europeo (Sus scrofa scrofa) y cerdo doméstico (Sus scrofa domestica) mediante el análisis por PCR de la región mitocondrial D-loop y del gen nuclear que codifica para el receptor 1 de la melanocortina (MC1R). La discriminación por PCR-RFLP de jabalí y cerdo en la región D loop no fue posible. Sin embargo, la técnica de PCR-RFLP desarrollada en el gen MC1R determinó perfiles de bandas característicos que permitieron la diferenciación de jabalí y cerdo mediante el empleo de las endonucleasas BspHI y BstUI.This work describes the differentiation of European wild boar (Sus scrofa scrofa) and domestic swine (Sus scrofa domestica) meats by PCR targeting sequences from the mitochondrial displacement loop (D-loop) region and the nuclear melanocortin receptor 1 (MC1R) gene. Detailed analysis of every D-loop sequence obtained indicated that PCR RFLP differentiation between wild and domestic Sus scrofa meats was not possible. Nevertheless, the PCR-RFLP technique developed targeting the MC1R gene generated characteristic PCR–RFLP profiles that allowed discrimination among meats from wild and domestic swine specimens using BspHI and BstUI endonucleases

Autentificación de carne y productos cárnicos procedentes de codorniz, faisán, perdiz y pintada mediante una técnica de PCR con cebadores especie-específicos

Polymerase chain reaction (PCR) based on oligonucleotide primers targeting the mitochondrial 12S rRNA gene has been applied to the specific identification of meats from quail (Coturnix coturnix), pheasant (Phasianus colchicus), partridge (Alectoris spp), and guinea fowl (Numida meleagris)

Despliegue de redes inalámbricas (WI-FI): planificación radio

Desde hace apenas tres años, una tecnología, o quizás sería más exacto, un protocolo de comunicaciones empezó a despuntar con éxito y vistas de un tremendo futuro. Esta tecnología basada en el estándar IEEE 802.11b y conocida como Wi-Fi (“Wireless Fidelity”) ha conseguido unos altos niveles de implantación, desbordar el ámbito de aplicaciones y servicios para los que fue inicialmente concebida y ser un poderoso complemento a otras tecnologías que requieren importantes infraestructuras y altos niveles de inversión

NGC 6067: A young and massive open cluster with high metallicity

© 2017 The Authors. NGC6067 is a young open cluster hosting the largest population of evolved stars among known Milky Way clusters in the 50-150 Ma age range. It thus represents the best laboratory in our Galaxy to constrain the evolutionary tracks of 5-7M⊙ stars. We have used high-resolution spectra of a large sample of bright cluster members (45), combined with archival photometry, to obtain accurate parameters for the cluster as well as stellar atmospheric parameters.We derive a distance of 1.78 ± 0.12 kpc, an age of 90 ± 20 Ma and a tidal radius of 14.8 -3.2+6.8 arcmin. We estimate an initial mass above 5700M⊙, for a present-day evolved population of two Cepheids, two A supergiants and 12 red giants with masses ≈6M⊙. We also determine chemical abundances of Li, O, Na, Mg, Si, Ca, Ti, Ni, Rb, Y and Ba for the red clump stars. We find a supersolar metallicity, [Fe/H]=+0.19 ± 0.05, and a homogeneous chemical composition, consistent with the Galactic metallicity gradient. The presence of a Li-rich red giant, star 276 with A(Li)=2.41, is also detected. An overabundance of Ba is found, supporting the enhanced s-process. The ratio of yellow to red giants is much smaller than 1, in agreement with models with moderate overshooting, but the properties of the cluster Cepheids do not seem consistent with current Padova models for supersolar metallicity