Carboxylated and esterified SWCNTs : characterization and contribution as components of biomaterials and solar cells

Date du colloque&nbsp;: 04/2010</p

Hydrogen physisorption channel on graphene: A highway for atomic H diffusion

We study the adsorption of atomic hydrogen on graphene by combining scanning tunneling microscopy experiments and first principle calculations. Our results reveal the existence of a physisorption channel over the graphene layer, dominated by van der Waals forces and thus homogeneous over the whole atomic lattice, where atomic hydrogen can move freely. Such physisorption channel is essential to understand the final configuration of hydrogen atoms chemisorbed on graphene. We find that ∼95% of chemisorbed H atoms form non-magnetic dimers even for very dilute concentrationsThis work was supported by Spain’s Ministerio de Economía y Competitividad under grants; PCIN-2015-030; FIS2015-64886-C5-5-P, MDM-2014-0377 and FIS2016-80434-P, by AEI and FEDER under projects MAT2016-80907-P and MAT2016-77852-C2-2-R (AEI/FEDER, UE), by the Fundación Ramón Areces, by the European Union through the FLAG ERA program and structural funds and by the Comunidad de Madrid MAD2D-CM program under grant S2013/MIT-3007

Biotin sulfone tagged oligomannosides as immunogens for eliciting antibodies against specific mannan epitopes

Biotinylated tri and tetrasaccharide: α Man (1→3) α Man (1→2) α Man; α Man (1→3) α Man (1→2) α Man (1→2) α Man were prepared using methyl tertbutyl phenyl thioglycosides glycosyl donors (MBP) and biotin sulfone strategy. Three key mannosyl thioglycosidic donors have been prepared: one for 1→2 linkage and two for the 1→3 linkage (protected with a 4,6-O-benzylidene or a 4,6-di-O-benzyl). The benzyliden protected one was not found reactive enough, and the benzylated donor was preferred. These biotinylated oligomanosides were evaluated as antigen in Crohn disease diagnosis and used coupled to streptavidin as hapten for eliciting polyclonal antibodies in mice

Tunable resonators for quantum circuits

We have designed, fabricated and measured high-Q $\lambda/2$ coplanar waveguide microwave resonators whose resonance frequency is made tunable with magnetic field by inserting a DC-SQUID array (including 1 or 7 SQUIDs) inside. Their tunability range is 30% of the zero field frequency. Their quality factor reaches up to 3$\times10^4$. We present a model based on thermal fluctuations that accounts for the dependance of the quality factor with magnetic field.Comment: subm. to JLTP (Proc. of LTD12 conference

Molecular characterization of a Streptococcus gallolyticus genomic island encoding a pilus involved in endocarditis.

Background. Streptococcus gallolyticus is a causative agent of infective endocarditis associated with colon cancer. Genome sequence of strain UCN34 revealed the existence of 3 pilus loci (pil1, pil2, and pil3). Pili are long filamentous structures playing a key role as adhesive organelles in many pathogens. The pil1 locus encodes 2 LPXTG proteins (Gallo2178 and Gallo2179) and 1 sortase C (Gallo2177). Gallo2179 displaying a functional collagen-binding domain was referred to as the adhesin, whereas Gallo2178 was designated as the major pilin. Methods. S. gallolyticus UCN34, Pil1(+) and Pil1(-), expressing various levels of pil1, and recombinant Lactococcus lactis strains, constitutively expressing pil1, were studied. Polyclonal antibodies raised against the putative pilin subunits Gallo2178 and Gallo2179 were used in immunoblotting and immunogold electron microscopy. The role of pil1 was tested in a rat model of endocarditis. Results. We showed that the pil1 locus (gallo2179-78-77) forms an operon differentially expressed among S. gallolyticus strains. Short pilus appendages were identified both on the surface of S. gallolyticus UCN34 and recombinant L. lactis-expressing pil1. We demonstrated that Pil1 pilus is involved in binding to collagen, biofilm formation, and virulence in experimental endocarditis. Conclusions. This study identifies Pil1 as the first virulence factor characterized in S. gallolyticus

Age at first birth in women is genetically associated with increased risk of schizophrenia

Prof. Paunio on PGC:n jäsenPrevious studies have shown an increased risk for mental health problems in children born to both younger and older parents compared to children of average-aged parents. We previously used a novel design to reveal a latent mechanism of genetic association between schizophrenia and age at first birth in women (AFB). Here, we use independent data from the UK Biobank (N = 38,892) to replicate the finding of an association between predicted genetic risk of schizophrenia and AFB in women, and to estimate the genetic correlation between schizophrenia and AFB in women stratified into younger and older groups. We find evidence for an association between predicted genetic risk of schizophrenia and AFB in women (P-value = 1.12E-05), and we show genetic heterogeneity between younger and older AFB groups (P-value = 3.45E-03). The genetic correlation between schizophrenia and AFB in the younger AFB group is -0.16 (SE = 0.04) while that between schizophrenia and AFB in the older AFB group is 0.14 (SE = 0.08). Our results suggest that early, and perhaps also late, age at first birth in women is associated with increased genetic risk for schizophrenia in the UK Biobank sample. These findings contribute new insights into factors contributing to the complex bio-social risk architecture underpinning the association between parental age and offspring mental health.Peer reviewe

Analysis of Odd-Mode Parametric Oscillations in HBT Multi-Stage Power Amplifiers

In this paper a technique for predicting odd-mode parametric oscillations from the analysis of exact pole-zero cancellations that take place in the frequency response obtained at some specific nodes of power amplifiers is presented. By using this technique the nature of parametric oscillations can be determined, which allows establishing a suitable strategy for circuit stabilization. The proposed methodology has been applied to the analysis and elimination of parametric odd-mode oscillations in an X- band two-stage MMIC power amplifier. The analysis has been complemented with the harmonic-balance calculation of the odd-mode frequency-divided steady-state solution