cLFV processes and suppression of non-unitary mixing effects in low scale seesaw models

We examine the parameter space region of the inverse seesaw model that is consistent with neutrino oscillation data. We focus on the correlation between the current limits from the search of the $\mu\to e\gamma$ lepton flavour violating decay and the non-standard effects associated with the presence of new heavy neutrino states. Unlike what we would expect from an inverse seesaw model, we have found a parametrization for the mass matrices in which the rates of charged lepton flavour-violating processes are negligible. Additionally, we provide a model where the inverse seesaw is obtained naturally, and the mass matrices get this structure with negligible violation of the lepton flavour.Comment: 20 pages, 3 figures and 3 table

Periodically modulated geometric and electronic structure of graphene on Ru(0001)

We report here on a method to fabricate and characterize highly perfect, periodically rippled graphene monolayers and islands, epitaxially grown on single crystal metallic substrates under controlled UHV conditions. The periodicity of the ripples is dictated by the difference in lattice parameters of graphene and substrate, and, thus, it is adjustable. We characterize its perfection at the atomic scale by means of STM and determine its electronic structure in the real space by local tunnelling spectroscopy. There are periodic variations in the geometric and electronic structure of the graphene monolayer. We observe inhomogeneities in the charge distribution, i.e a larger occupied Density Of States at the higher parts of the ripples. Periodically rippled graphene might represent the physical realization of an ordered array of coupled graphene quantum dots. The data show, however, that for rippled graphene on Ru(0001) both the low and the high parts of the ripples are metallic. The fabrication of periodically rippled graphene layers with controllable characteristic length and different bonding interactions with the substrate will allow a systematic experimental test of this fundamental problem.Comment: 12 pages. Contribution to the topical issue on graphene of Semiconductor Science and Technolog

Nanocomposite Polymer Electrolyte Membranes: Methanol Crossover and Conductivity

Commercial Nafion® 117 membranes were successfully modified by in-situ reactions (sol-gel of TEOS and/or polymerization of aniline) within Nafion structures. Water-methanol permeability and proton conductivity were investigated in order to determine the potential performance of these membranes for DMFC systems. Silica-polyaniline modification resulted in 84% methanol crossover reduction, from 2.45x10^-5 cm2.s^-1 for conventional Nafion membranes to 3.71x10^-6 cm2.s^-1 for the modified silica-polyaniline composite membrane at 75 degrees C. In addition, conductivity was not hindered, as the polyaniline-Nafion membrane increased from 12.2 to 15 mS.cm^-1 as compared to Nafion, while a reduction of 11% was observed for silica-polyaniline-Nafion composite membrane. The results in this work strongly suggest the potential of polyaniline nanocomposites to enhance the performance of DMFCs

Acetylation of the HIV-1 Tat protein by p300 is important for its transcriptional activity.

AbstractThe human immunodeficiency virus 1 (HIV-1) Tat protein activates transcriptional elongation by recruiting the positive transcription elongation factor (pTEFb) complex to the TAR RNA element, which is located at the 5′ extremity of all viral transcripts [1–3]. Tat also associates in vitro and in vivo with the transcriptional coactivator p300/CBP [4–6]. This association has been proposed to recruit the histone acetyltransferase (HAT) activity of p300 to the integrated HIV-1 promoter. We have observed that the purified p300 HAT domain acetylates recombinant Tat proteins in vitro and that Tat is acetylated in vivo. The major targets of acetylation by p300 are lysine residues (Lys50 and Lys51) in the arginine-rich motif (ARM) used by Tat to bind RNA and for nuclear import. Mutation of these residues in full-length recombinant Tat blocked its acetylation in vitro. Furthermore, mutation of these lysine residues to arginine markedly decreased the synergistic activation of he HIV promoter by Tat and p300 or by Tat and cyclin T1. These results demonstrate that acetylation of Tat by p300/CBP is important for its transcriptional activation of the HIV promoter

Periodically modulated geometric and electronic structure of graphene on Ru(0001)

We report here on a method to fabricate and characterize highly perfect, periodically rippled graphene monolayers and islands, epitaxially grown on single crystal metallic substrates under controlled UHV conditions. The periodicity of the ripples is dictated by the difference in lattice parameters of graphene and substrate, and, thus, it is adjustable. We characterize its perfection at the atomic scale by means of STM and determine its electronic structure in the real space by local tunnelling spectroscopy. There are periodic variations in the geometric and electronic structure of the graphene monolayer. We observe inhomogeneities in the charge distribution, i.e a larger occupied Density Of States at the higher parts of the ripples. Periodically rippled graphene might represent the physical realization of an ordered array of coupled graphene quantum dots. The data show, however, that for rippled graphene on Ru(0001) both the low and the high parts of the ripples are metallic. The fabrication of periodically rippled graphene layers with controllable characteristic length and different bonding interactions with the substrate will allow a systematic experimental test of this fundamental problem.Comment: 12 pages. Contribution to the topical issue on graphene of Semiconductor Science and Technolog

Batch to the future: Analyzing timestamp accuracy of high-performance packet I/O engines

Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. V. Moreno, P. M. S. Del Rio, J. Ramos, J. J. Garnica, and J. L. Garcia-Dorado, "Batch to the future: Analyzing timestamp accuracy of high-performance packet I/O engines", IEEE Communications Letters, vol. 16, no. 11, pp. 1888 - 1891, November 2012.Novel packet I/O engines allow capturing traffic at multi-10Gb/s using only-software and commodity-hardware systems. This is achieved thanks to the application of techniques such as batch processing. Nevertheless, this feature involves degradation in the timestamp accuracy, which may be relevant for monitoring purposes. We propose two different approaches to mitigate such effect: a simple algorithm to distribute inter-batch time among the packets composing a batch, and a driver modification to poll NIC buffers avoiding batch processing. Experimental results, using both synthetic and real traffic, show that our proposals allow capturing accurately timestamped traffic for monitoring purposes at multi-10Gb/s rates

Microbial rDNA sequences as markers to determine microbial synthesis in Rusitec fermenters: A comparison with 15N

Microbial rDNA sequences have been proposed as potential internal markers to determine microbial synthesis in the rumen. The objective of this experiment was to compare values of microbial growth determined using 15N as external marker with concentrations of microbial DNA in fermenters, and to assess if both procedures detected similar differences between diets and solid (SOL) and liquid (LIQ) digesta phases

Survey and analysis of microsatellites from transcript sequences in Phytophthora species: frequency, distribution, and potential as markers for the genus

BACKGROUND: Members of the genus Phytophthora are notorious pathogens with world-wide distribution. The most devastating species include P. infestans, P. ramorum and P. sojae. In order to develop molecular methods for routinely characterizing their populations and to gain a better insight into the organization and evolution of their genomes, we used an in silico approach to survey and compare simple sequence repeats (SSRs) in transcript sequences from these three species. We compared the occurrence, relative abundance, relative density and cross-species transferability of the SSRs in these oomycetes. RESULTS: The number of SSRs in oomycetes transcribed sequences is low and long SSRs are rare. The in silico transferability of SSRs among the Phytophthora species was analyzed for all sets generated, and primers were selected on the basis of similarity as possible candidates for transferability to other Phytophthora species. Sequences encoding putative pathogenicity factors from all three Phytophthora species were also surveyed for presence of SSRs. However, no correlation between gene function and SSR abundance was observed. The SSR survey results, and the primer pairs designed for all SSRs from the three species, were deposited in a public database. CONCLUSION: In all cases the most common SSRs were trinucleotide repeat units with low repeat numbers. A proportion (7.5%) of primers could be transferred with 90% similarity between at least two species of Phytophthora. This information represents a valuable source of molecular markers for use in population genetics, genetic mapping and strain fingerprinting studies of oomycetes, and illustrates how genomic databases can be exploited to generate data-mining filters for SSRs before experimental validation

A mixture of anatase and rutile TiO2 nanoparticles induces histamine secretion in mast cells

<p>Abstract</p> <p>Background</p> <p>Histamine released from mast cells, through complex interactions involving the binding of IgE to FcεRI receptors and the subsequent intracellular Ca²⁺signaling, can mediate many allergic/inflammatory responses. The possibility of titanium dioxide nanoparticles (TiO₂NPs), a nanomaterial pervasively used in nanotechnology and pharmaceutical industries, to directly induce histamine secretion without prior allergen sensitization has remained uncertain.</p> <p>Results</p> <p>TiO₂NP exposure increased both histamine secretion and cytosolic Ca²⁺concentration ([Ca²⁺]_C) in a dose dependent manner in rat RBL-2H3 mast cells. The increase in intracellular Ca²⁺levels resulted primarily from an extracellular Ca²⁺influx via membrane L-type Ca²⁺channels. Unspecific Ca²⁺entry via TiO₂NP-instigated membrane disruption was demonstrated with the intracellular leakage of a fluorescent calcein dye. Oxidative stress induced by TiO₂NPs also contributed to cytosolic Ca²⁺signaling. The PLC-IP₃-IP₃receptor pathways and endoplasmic reticulum (ER) were responsible for the sustained elevation of [Ca²⁺]_Cand histamine secretion.</p> <p>Conclusion</p> <p>Our data suggests that systemic circulation of NPs may prompt histamine release at different locales causing abnormal inflammatory diseases. This study provides a novel mechanistic link between environmental TiO₂NP exposure and allergen-independent histamine release that can exacerbate manifestations of multiple allergic responses.</p