1,414 research outputs found
Numerical and Comparative Study of the Agility of Planar Transmission Lines printed on a Ferroelectric Thin Film
International audienceIn this paper, we report on simulation results at 10 GHz of planar transmission lines (TL) printed on a ferroelectric thin film deposited on sapphire and lanthanum aluminate substrates. The ferroelectric film permittivity is supposed to vary from 700 to 500. First, the main properties of microstrip (MS), coplanar waveguide (CPW) and coplanar strips (CS) namely their effective permittivity, characteristic impedance and insertion loss are computed as a function of the physical and electrical parameters. Then their tunability and figure of merit are defined and compared. CPW and CS lines present a tunability (eff/eff_max) of about 16 % for a gap value g = 30 ΞΌm. The MS lines show a much less tenability of 2%. Moreover, the figure of merit of CPW and CS configurations are of 6.3 and 12.2 %/dB for a gap value of 30 ΞΌm, respectively. By increasing the gap, these figures of merit can be improved up to the limiting values of 8.7 and 15.4 %/dB, respectively
Multiplex PCR for detection of plasmid-mediated colistin resistance determinants, mcr-1, mcr-2, mcr-3, mcr-4 and mcr-5 for surveillance purposes
International audiencePlasmid-mediated colistin resistance mechanisms have been identified worldwide in the past years. A multiplex polymerase chain reaction (PCR) protocol for detection of all currently known transferable colistin resistance genes (mcr-1 to mcr-5, and variants) in Enterobacteriaceae was developed for surveillance or research purposes. Methods: We designed four new primer pairs to amplify mcr-1, mcr-2, mcr-3 and mcr-4 gene products and used the originally described primers for mcr-5 to obtain a stepwise separation of ca 200 bp between amplicons. The primer pairs and amplification conditions allow for single or multiple detection of all currently described mcr genes and their variants present in Enterobacteriaceae. The protocol was validated testing 49 European Escherichia coli and Salmonella isolates of animal origin. Results: Multiplex PCR results in bovine and porcine isolates from Spain, Germany, France and Italy showed full concordance with whole genome sequence data. The method was able to detect mcr-1, mcr-3 and mcr-4 as singletons or in different combinations as they were present in the test isolates. One new mcr-4 variant, mcr-4.3, was also identified. Conclusions: This method allows rapid identification of mcr-positive bacteria and overcomes the challenges of phenotypic detection of colistin resistance. The multiplex PCR should be particularly interesting in settings or laboratories with limited resources for performing genetic analysis as it provides information on the mechanism of colistin resistance without requiring genome sequencing
Attributable deaths and disability-adjusted life-years caused by infections with antibiotic-resistant bacteria in the EU and the European Economic Area in 2015: a population-level modelling analysis
Background: Infections due to antibiotic-resistant bacteria are threatening modern health care. However, estimating their incidence, complications, and attributable mortality is challenging. We aimed to estimate the burden of infections caused by antibiotic-resistant bacteria of public health concern in countries of the EU and European Economic Area (EEA) in 2015, measured in number of cases, attributable deaths, and disability-adjusted life-years (DALYs).
Methods: We estimated the incidence of infections with 16 antibiotic resistanceβbacterium combinations from European Antimicrobial Resistance Surveillance Network (EARS-Net) 2015 data that was country-corrected for population coverage. We multiplied the number of bloodstream infections (BSIs) by a conversion factor derived from the European Centre for Disease Prevention and Control point prevalence survey of health-care-associated infections in European acute care hospitals in 2011β12 to estimate the number of non-BSIs. We developed disease outcome models for five types of infection on the basis of systematic reviews of the literature.
Findings: From EARS-Net data collected between Jan 1, 2015, and Dec 31, 2015, we estimated 671β689 (95% uncertainty interval [UI] 583β148β763β966) infections with antibiotic-resistant bacteria, of which 63Β·5% (426β277 of 671β689) were associated with health care. These infections accounted for an estimated 33β110 (28β480β38β430) attributable deaths and 874β541 (768β837β989β068) DALYs. The burden for the EU and EEA was highest in infants (aged <1 year) and people aged 65 years or older, had increased since 2007, and was highest in Italy and Greece.
Interpretation: Our results present the health burden of five types of infection with antibiotic-resistant bacteria expressed, for the first time, in DALYs. The estimated burden of infections with antibiotic-resistant bacteria in the EU and EEA is substantial compared with that of other infectious diseases, and has increased since 2007. Our burden estimates provide useful information for public health decision-makers prioritising interventions for infectious diseases
Breakpoints in immunoregulation required for Th1 cells to induce diabetes
We describe a novel TCR-transgenic mouse line, TCR7, where MHC class II-restricted, CD4+ T cells are specific for the subdominant H-2b epitope (HEL74-88) of hen egg lysozyme (HEL), and displayed an increased frequency in the thymus and in peripheral lymphoid compartments over that seen in non-transgenic littermate controls. CD4+ T cells responded vigorously to HEL or HEL74-88 epitope presented on APC and could develop into Th1 or Th2 cells under appropriate conditions. Adoptive transfer of TCR7 Ly5.1 T cells into Ly5.2 rat insulin promoter (RIP)-HEL transgenic recipient hosts did not lead to expansion of these cells or result in islet infiltration, although these TCR7 cells could expand upon transfer into mice expressing high levels of HEL in the serum. Islet cell infiltration only occurred when the TCR7 cells had been polarized to either a Th1 or Th2 phenotype prior to transfer, which led to insulitis. Progression from insulitis to autoimmune diabetes only occurred in these recipients when Th1 but not Th2 TCR7 cells were transferred and CTLA-4 signaling was simultaneously blocked. These findings show that regulatory pathways such as CTLA-4 can hold in check already differentiated autoreactive effector Th1 cells, to inhibit the transition from tolerance to autoimmune diabetes.Schering Plough Research Institute, NJ, and then
continued by the Medical Research Council, U
Optimal anchoring of a foldamer inhibitor of ASF1 histone chaperone through backbone plasticity
Sequence-specific oligomers with predictable folding patterns, i.e., foldamers, provide new opportunities to mimic.-helical peptides and design inhibitors of protein-protein interactions. One major hurdle of this strategy is to retain the correct orientation of key side chains involved in protein surface recognition. Here, we show that the structural plasticity of a foldamer backbone may notably contribute to the required spatial adjustment for optimal interaction with the protein surface. By using oligoureas as. helix mimics, we designed a foldamer/peptide hybrid inhibitor of histone chaperone ASF1, a key regulator of chromatin dynamics. The crystal structure of its complex with ASF1 reveals a notable plasticity of the urea backbone, which adapts to the ASF1 surface to maintain the same binding interface. One additional benefit of generating ASF1 ligands with nonpeptide oligourea segments is the resistance to proteolysis in human plasma, which was highly improved compared to the cognate alpha-helical peptide
The Near Infrared Imager and Slitless Spectrograph for JWST -- V. Kernel Phase Imaging and Data Analysis
Kernel phase imaging (KPI) enables the direct detection of substellar
companions and circumstellar dust close to and below the classical (Rayleigh)
diffraction limit. We present a kernel phase analysis of JWST NIRISS full pupil
images taken during the instrument commissioning and compare the performance to
closely related NIRISS aperture masking interferometry (AMI) observations. For
this purpose, we develop and make publicly available the custom "Kpi3Pipeline"
enabling the extraction of kernel phase observables from JWST images. The
extracted observables are saved into a new and versatile kernel phase FITS file
(KPFITS) data exchange format. Furthermore, we present our new and publicly
available "fouriever" toolkit which can be used to search for companions and
derive detection limits from KPI, AMI, and long-baseline interferometry
observations while accounting for correlated uncertainties in the model fitting
process. Among the four KPI targets that were observed during NIRISS instrument
commissioning, we discover a low-contrast (~1:5) close-in (~1 )
companion candidate around CPD-66~562 and a new high-contrast (~1:170)
detection separated by ~1.5 from 2MASS~J062802.01-663738.0. The
5- companion detection limits around the other two targets reach ~6.5
mag at ~200 mas and ~7 mag at ~400 mas. Comparing these limits to those
obtained from the NIRISS AMI commissioning observations, we find that KPI and
AMI perform similar in the same amount of observing time. Due to its 5.6 times
higher throughput if compared to AMI, KPI is beneficial for observing faint
targets and superior to AMI at separations >325 mas. At very small separations
(<100 mas) and between ~250-325 mas, AMI slightly outperforms KPI which suffers
from increased photon noise from the core and the first Airy ring of the
point-spread function.Comment: 34 pages, 17 figures, accepted for publication in PAS
Th1 Disabled Function in Response to TLR4 Stimulation of Monocyte-Derived DC from Patients Chronically-Infected by Hepatitis C Virus
Background: Lack of protective antibodies and inefficient cytotoxic responses are characteristics of chronic hepatitis C infection. A defect in dendritic cell (DC) function has thus been suspected, but this remains a controversial issue. Methods and Findings: Here we show that monocyte-derived DC (MoDC) from chronically-infected patients can mature in response to TLR1/2, TLR2/6 or TLR3 ligands. In contrast, when stimulated with the TLR4 ligand LPS, MoDC from patients show a profound defect in inducing IFNc secretion by allogeneic T cells. This defect is not due to defective phenotypic maturation or to the presence of HCV-RNA in DC or monocytes but is correlated to reduced IL-12 secretion by DC. Restoration of DC ability to stimulate IFNc secretion can be obtained by blocking MEK activation in DC, indicating that MEK/ ERK pathway is involved in the Th1 defect of MoDC. Monocytes from HCV patients present increased spontaneous secretion of cytokines and chemokines, especially MIP-1b. Addition of MIP-1b on healthy monocytes during differentiation results in DC that have Th1 defect characteristic of MoDC from HCV patients, suggesting that MIP-1b secretion by HCV monocytes participates in the Th1 defect of DC. Conclusions: Our data indicate that monocytes from HCV patients are activated in vivo. This interferes with their differentiation into DC, leading to deficient TLR4 signaling in these cells that are enable to induce a Th1 response. Thi
Secretion of Hepatitis C Virus Envelope Glycoproteins Depends on Assembly of Apolipoprotein B Positive Lipoproteins
The density of circulating hepatitis C virus (HCV) particles in the blood of chronically infected patients is very heterogeneous. The very low density of some particles has been attributed to an association of the virus with apolipoprotein B (apoB) positive and triglyceride rich lipoproteins (TRL) likely resulting in hybrid lipoproteins known as lipo-viro-particles (LVP) containing the viral envelope glycoproteins E1 and E2, capsid and viral RNA. The specific infectivity of these particles has been shown to be higher than the infectivity of particles of higher density. The nature of the association of HCV particles with lipoproteins remains elusive and the role of apolipoproteins in the synthesis and assembly of the viral particles is unknown. The human intestinal Caco-2 cell line differentiates in vitro into polarized and apoB secreting cells during asymmetric culture on porous filters. By using this cell culture system, cells stably expressing E1 and E2 secreted the glycoproteins into the basal culture medium after one week of differentiation concomitantly with TRL secretion. Secreted glycoproteins were only detected in apoB containing density fractions. The E1βE2 and apoB containing particles were unique complexes bearing the envelope glycoproteins at their surface since apoB could be co-immunoprecipitated with E2-specific antibodies. Envelope protein secretion was reduced by inhibiting the lipidation of apoB with an inhibitor of the microsomal triglyceride transfer protein. HCV glycoproteins were similarly secreted in association with TRL from the human liver cell line HepG2 but not by Huh-7 and Huh-7.5 hepatoma cells that proved deficient for lipoprotein assembly. These data indicate that HCV envelope glycoproteins have the intrinsic capacity to utilize apoB synthesis and lipoprotein assembly machinery even in the absence of the other HCV proteins. A model for LVP assembly is proposed
Trastuzumab Deruxtecan in HER2-Positive Metastatic Breast Cancer Patients with Brain Metastases: A DESTINY-Breast01 Subgroup Analysis.
peer reviewed[en] UNLABELLED: DESTINY-Breast01 (NCT03248492) evaluated trastuzumab deruxtecan (T-DXd; DS-8201) in patients with heavily pretreated HER2-positive metastatic breast cancer (mBC). We present a subgroup of 24 patients with a history of treated brain metastases (BM), a population with limited treatment options. In patients with BMs, the confirmed objective response rate (cORR) was 58.3% [95% confidence interval (CI), 36.6%-77.9%], and the median progression-free survival (mPFS) was 18.1 months (95% CI, 6.7-18.1 months). In patients without BMs (n = 160), cORR was 61.3% and mPFS was 16.4 months. Eight patients (47.1%) experienced a best overall intracranial response of partial response or complete response. Seven patients (41.2%) had a best percentage change in brain lesion diameter from baseline consistent with stable disease. Two patients (8.3%) with BMs and two (1.3%) without BMs experienced progression in the brain. The safety profile of T-DXd was consistent with previous studies. The durable clinical activity of T-DXd in this population warrants further investigation.
SIGNIFICANCE: Advances in treating HER2-positive metastatic breast cancer have greatly improved patient outcomes, but intracranial progression remains an important risk for which few therapeutic options are currently available. T-DXd demonstrated durable efficacy in patients with stable, treated BMs. This article is highlighted in the In This Issue feature, p. 2711
The Role of Humoral Innate Immunity in Hepatitis C Virus Infection
Infection with Hepatitis C Virus (HCV) causes chronic disease in approximately 80% of cases, resulting in chronic inflammation and cirrhosis. Current treatments are not completely effective, and a vaccine has yet to be developed. Spontaneous resolution of infection is associated with effective host adaptive immunity to HCV, including production of both HCV-specific T cells and neutralizing antibodies. However, the supporting role of soluble innate factors in protection against HCV is less well understood. The innate immune system provides an immediate line of defense against infections, triggering inflammation and playing a critical role in activating adaptive immunity. Innate immunity comprises both cellular and humoral components, the humoral arm consisting of pattern recognition molecules such as complement C1q, collectins and ficolins. These molecules activate the complement cascade, neutralize pathogens, and recruit antigen presenting cells. Here we review the current understanding of anti-viral components of the humoral innate immune system that play a similar role to antibodies, describing their role in immunity to HCV and their potential contribution to HCV pathogenesis
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