93 research outputs found
Versatile spectroscopic cell for operando studies in heterogeneous catalysis using tender Xâray spectroscopy in fluorescence mode
Mirror Furnace for Synchrotron Dark Field X-ray Microscopy Experiments
We present a multi-purpose mirror furnace designed for synchrotron X-ray
experiments. The furnace is optimized specifically for dark-field X-ray
microscopy (DFXM) of crystalline materials at the beamline ID06 of the ESRF.
The furnace can reach up to ~1600{\deg}C with stability better than 2{\deg}C,
and heating and cooling rates up to 30{\deg}C/s. The contact-less design
enables samples to be heated either in air or in a controlled atmosphere in a
capillary tube. The temperature was calibrated via the thermal expansion of an
a-iron grain. Temperature profiles in the y and z axes were measured by
scanning a thermocouple through the focal spot of the furnace. In the current
configuration of the beamline, the furnace can be used for DFXM, near-field
X-ray topography, bright field X-ray nanotomography, high resolution reciprocal
space mapping, and limited powder diffraction experiments. As a first
application, we present a DFXM case study on isothermal heating of a
commercially pure Al single crystal
Simultaneous resonant x-ray diffraction measurement of polarization inversion and lattice strain in polycrystalline ferroelectrics
International audienceStructure-property relationships in ferroelectrics extend over several length scales from the individual unit cell to the macroscopic device, and with dynamics spanning a broad temporal domain. Characterizing the multi-scale structural origin of electric field-induced polarization reversal and strain in ferroelectrics is an ongoing challenge that so far has obscured its fundamental behaviour. By utilizing small intensity differences between Friedel pairs due to resonant scattering, we demonstrate a time-resolved X-ray diffraction technique for directly and simultaneously measuring both lattice strain and, for the first time, polarization reversal during in-situ electrical perturbation. This technique is demonstrated for BaTiO3-BiZn0.5Ti0.5O3 (BT-BZT) polycrystalline ferroelectrics, a prototypical lead-free piezoelectric with an ambiguous switching mechanism. This combines the benefits of spectroscopic and diffraction-based measurements into a single and robust technique with time resolution down to the ns scale, opening a new door to in-situ structure-property characterization that probes the full extent of the ferroelectric behaviou
Characterizing and Comparing the Seasonality of Influenza-Like Illnesses and Invasive Pneumococcal Diseases Using Seasonal Waveforms
Recommended from our members
Simultaneous resonant x-ray diffraction measurement of polarization inversion and lattice strain in polycrystalline ferroelectrics
Structure-property relationships in ferroelectrics extend over several length scales from the individual unit cell to the macroscopic device, and with dynamics spanning a broad temporal domain. Characterizing the multi-scale structural origin of electric field-induced polarization reversal and strain in ferroelectrics is an ongoing challenge that so far has obscured its fundamental behaviour. By utilizing small intensity differences between Friedel pairs due to resonant scattering, we demonstrate a time-resolved X-ray diffraction technique for directly and simultaneously measuring both lattice strain and, for the first time, polarization reversal during in-situ electrical perturbation. This technique is demonstrated for BaTiOâ-BiZnâ.â
Tiâ.â
Oâ (BT-BZT) polycrystalline ferroelectrics, a prototypical lead-free piezoelectric with an ambiguous switching mechanism. This combines the benefits of spectroscopic and diffraction-based measurements into a single and robust technique with time resolution down to the ns scale, opening a new door to in-situ structure-property characterization that probes the full extent of the ferroelectric behaviour.This is the publisherâs final pdf. The published article is copyrighted by the author(s) and published by the Nature Publishing Group. The published article can be found at: http://www.nature.com/srep
Influence of FCGRT gene polymorphisms on pharmacokinetics of therapeutic antibodies
The neonatal Fc receptor (FcRn) encoded by FCGRT is known to be involved in the pharmacokinetics (PK) of therapeutic monoclonal antibodies (mAbs). Variability in the expression of FCGRT gene and consequently in the FcRn protein level could explain differences in PK observed between patients treated with mAbs. We studied whether the previously described variable number tandem repeat (VNTR) or copy number variation (CNV) of FCGRT are associated with individual variations of PK parameters of cetuximab. VNTR and CNV were assessed on genomic DNA of 198 healthy individuals and of 94 patients treated with the therapeutic mAb. VNTR and CNV were analyzed by allele-specific PCR and duplex real-time PCR with TaqmanÂź technology, respectively. The relationship between FCGRT polymorphisms (VNTR and CNV) and PK parameters of patients treated with cetuximab was studied. VNTR3 homozygote patients had a lower cetuximab distribution clearance than VNTR2/VNTR3 and VNTR3/VNTR4 patients (p = 0.021). We observed no affects of VNTR genotype on elimination clearance. One healthy person (0.5%) and 1 patient (1.1%) had 3 copies of FCGRT. The PK parameters of this patient did not differ from those of patients with 2 copies. The FCGRT promoter VNTR may influence mAbsâ distribution in the body. CNV of FCGRT cannot be used as a relevant pharmacogenetic marker because of its low frequency
Significant Reduction of Antibiotic Use in the Community after a Nationwide Campaign in France, 2002â2007
Didier Guillemot and colleagues describe the evaluation of a nationwide programme in France aimed at decreasing unnecessary outpatient prescriptions for antibiotics. The campaign was successful, particularly in reducing prescriptions for children
Hunting dogs as sentinel animals for monitoring infections with Trichinella spp. in wildlife
Genome wide linkage study, using a 250K SNP map, of Plasmodium falciparum infection and mild malaria attack in a Senegalese population
Multiple factors are involved in the variability of host's response to P. falciparum infection, like the intensity and seasonality of malaria transmission, the virulence of parasite and host characteristics like age or genetic make-up. Although admitted nowadays, the involvement of host genetic factors remains unclear. Discordant results exist, even concerning the best-known malaria resistance genes that determine the structure or function of red blood cells. Here we report on a genomewide linkage and association study for P. falciparum infection intensity and mild malaria attack among a Senegalese population of children and young adults from 2 to 18 years old. A high density single nucleotide polymorphisms (SNP) genome scan (Affimetrix GeneChip Human Mapping 250K-nsp) was performed for 626 individuals: i.e. 249 parents and 377 children out of the 504 ones included in the follow-up. The population belongs to a unique ethnic group and was closely followed-up during 3 years. Genome-wide linkage analyses were performed on four clinical and parasitological phenotypes and association analyses using the family based association tests (FBAT) method were carried out in regions previously linked to malaria phenotypes in literature and in the regions for which we identified a linkage peak. Analyses revealed three strongly suggestive evidences for linkage: between mild malaria attack and both the 6p25.1 and the 12q22 regions (empirical p-value = 5 x 10(-5) and 96 x 10(-5) respectively), and between the 20p11q11 region and the prevalence of parasite density in asymptomatic children (empirical p-value = 1.5 x 10(-4)). Family based association analysis pointed out one significant association between the intensity of plasmodial infection and a polymorphism located in ARHGAP26 gene in the 5q31-q33 region (p-value = 3.7 x 10(-5)). This study identified three candidate regions, two of them containing genes that could point out new pathways implicated in the response to malaria infection. Furthermore, we detected one gene associated with malaria infection in the 5q31-q33 region
Platelet profile is associated with clinical complications in patients with vivax and falciparum malaria in Colombia
- âŠ