Besides the potential to identify a wide variety of gastrointestinal parasites, microscopy remains the reference standard in clinical microbiology for amoeba species identification and, especially ...when coupled with adhesin detection, to discriminate the pathogenic Entamoeba histolytica from its sister but non-pathogenic species Entamoeba dispar/Entamoeba moshkovskii. However, this approach is time-consuming, requires a high-level of expertise that can be jeopardized considering the low prevalence of gastrointestinal parasites in non-endemic countries. Here, we evaluated the CE-IVD-marked multiplex PCR (ParaGENIE G-Amoeba, Ademtech) targeting E. histolytica and E. dispar/E. moshkovskii and Giardia intestinalis.
This evaluation was performed blindly on a reference panel of 172 clinical stool samples collected prospectively from 12 laboratories and analysed using a standardized protocol relying on microscopy (and adhesin detection by ELISA for the detection of E. histolytica) including G. intestinalis (n = 37), various amoeba species (n = 55) including E. dispar (n = 15), E. histolytica (n = 5), as well as 17 other gastrointestinal parasites (n = 80), and negative samples (n = 37).
This new multiplex PCR assay offers fast and reliable results with appropriate sensitivity and specificity for the detection of G. intestinalis and E. dispar/E. moshkovskii from stools (89.7%/96.9% and 95%/100%, respectively). Detection rate and specificity were greatly improved by the PCR assay, highlighting several samples misidentified by microscopy, including false-negative and false-positive results for both E. dispar/E. moshkovskii and E. histolytica.
Given the clinical relevance of amoeba species identification, microbiologists should be aware of the limitations of using an algorithm relying on microscopy coupled with adhesin detection by ELISA.
This paper presents an identification procedure for the parameters of a thermodynamically based constitutive model for Shape memory Alloys (SMAs). The proposed approach is a gradient-based method and ...utilizes an analytical computation of the sensitivity matrix. For several loading cases, including superelasticity, that are commonly utilized for the model parameters identification of such a constitutive model, a closed-form of the total infinitesimal strain is derived. The partial derivatives of this state variable are developed to find the components of the sensitivity matrix. A Levenberg–Marquardt algorithm is utilized to solve the inverse problem and find the best set of model parameters for specific SMA materials. Moreover, a pre-identification method, based on the second derivative of the total strain components is proposed. This provides a suitable initial set of model parameters, which increases the efficiency of the inverse method. The proposed approach is applied for the simultaneous identification of the non-linear constitutive parameters for two superelastic SMAs. The comparison between experimental and numerical curves obtained for different temperatures shows the capabilities of the developed identification approach. The robustness and the efficiency of the developed approach are then experimentally validated.
•An identification method for shape memory alloys material parameters is proposed.•A formulation of the thermodynamical model is adapted for superelastic SMAs.•Closed form of the total strain is obtained for multiaxial superelastic loading paths.•Analytical sensitivity matrix is derived from closed form of the total strain.•Experimental validation for two SMAs under thermomechanical loadings.
“ZenGen” is a script-tool which helps us to automatically generate first-principles input files of all the ordered compounds of a given crystal structure in a given system. The complete set of heats ...of formation of each end-members can then easily be used in the thermodynamic phase modeling. “ZenGen” is a free and open source code, which can be downloaded from http://zengen.cnrs.fr.
In order to test its applicability, we have chosen the quaternary system, Cr–Mo–Ni–Re as a case study to be investigated. The binary solid solution parameters have been estimated from special quasirandom structures (SQS) calculations. The σ-phase has been fully described without any adaptation to its crystal structure, i.e. with a 5-sublattice model, through first-principles calculation of the 45=1024 different ordered quaternary configurations. Several tentative ab initio phase diagrams are presented.
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Abstract
Laser wakefield accelerators commonly produce on-axis, low-divergence, high-energy electron beams. However, a high charge, annular shaped beam can be trapped outside the bubble and ...accelerated to high energies. Here we present a parametric study on the production of low-energy-spread, ultra-relativistic electron ring beams in a two-stage gas cell. Ring-shaped beams with energies higher than 750 MeV are observed simultaneously with on axis, continuously injected electrons. Often multiple ring shaped beams with different energies are produced and parametric studies to control the generation and properties of these structures were conducted. Particle tracking and particle-in-cell simulations are used to determine properties of these beams and investigate how they are formed and trapped outside the bubble by the wake produced by on-axis injected electrons. These unusual femtosecond duration, high-charge, high-energy, ring electron beams may find use in beam driven plasma wakefield accelerators and radiation sources.
We first devise a branching algorithm that computes a minimum independent dominating set with running time O∗(1.3351n)=O∗(20.417n) and polynomial space. This improves upon the best state of the art ...algorithms for this problem. We then study approximation of the problem by moderately exponential time algorithms and show that it can be approximated within ratio 1+ϵ, for any ϵ>0, in a time smaller than the one of exact computation and exponentially decreasing with ϵ. We also propose approximation algorithms with better running times for ratios greater than 3 in general graphs and give improved moderately exponential time approximation results in triangle-free and bipartite graphs. These latter results are based upon a new bound on the number of maximal independent sets of a given size in these graphs, which is a result interesting per se.
Infections due to Candida spp. are frequent, particularly in immunocompromised and intensive care unit patients. Antifungal susceptibility tests are now required to optimize antifungal treatment ...given the emergence of acquired antifungal resistance in some Candida species. An antifungal susceptibility automated method, the Vitek 2 system (VK2), was evaluated. VK2 was compared to the CLSI broth microdilution reference method and the Etest procedure. For this purpose, 205 clinical isolates of Candida spp., including 11 different species, were tested for fluconazole, voriconazole, and amphotericin B susceptibility. For azoles, essential agreement ranged from 25% to 100%, depending on the method used and the Candida species tested. Categorical agreements for all of the species averaged 92.2% and ranged from 14.3 to 100%, depending on the 24-h or 48-h MIC reading by the Etest and CLSI methods and on the Candida species. Results obtained for Candida albicans showed excellent categorical and essential agreements with the two comparative methods. For Candida glabrata, the essential agreement was high with the CLSI method but low with the Etest method, and several very major errors in interpretation were observed between VK2 and the Etest method for both azoles. Low MICs of fluconazole were obtained for all of the Candida krusei isolates, but the VK2 expert software corrected all of the results obtained to resistant. Amphotericin B results showed MICs of less-than or equal to1 mg/liter for 201 (VK2), 190 (CLSI), and 202 (Etest) isolates. The AST-YS01 Vitek 2 card system (bioMérieux) is a reliable and practical standardized automated antifungal susceptibility test. Nevertheless, more assays are needed to better evaluate C. glabrata fluconazole sensitivity.
Due to large outbreaks observed worldwide, Candida auris has emerged as a major threat to healthcare facilities. To prevent these phenomena, a systematic screening should be performed in patients ...transferred from regions where the pathogen is highly endemic. In this study, we recorded and analyzed French mycologists' current knowledge and practice regarding C. auris screening and diagnosis. Thirty-six centers answered an online questionnaire. Only 11 (30.6 %) participants were aware of any systematic screening for C. auris for patients admitted to their hospital. In the case of post-admission screening, axillae/groins (n = 21), nares (n = 7), rectum (n = 9), and mouth (n = 6) alone or various combinations were the body sites the most frequently sampled. Only six centers (8.3 %) reported using a commercially available plate allowing the differentiation of C. auris colonies from that of other Candida species, while five laboratories (13.8 %) had implemented a C. auris-specific qPCR. Considering the potential impact on infected patients and the risk of disorganization in the care of patients, it is crucial to remember to biologists and clinicians the utmost importance of systematic screening on admission.
The generation of GeV-scale electron beams in a gas-filled capillary discharge waveguide with good reproducibility is discussed. Beams of electrons with energies above 900 MeV, and with ...root-mean-square divergences of 3.5 mrad, are observed for a plasma density of 2.2 × 1018 cm−3 and a peak input laser power of 55 TW. The variation of the maximum electron energy with the plasma density is measured and found to agree well with simple models. Injection and acceleration of electrons at the to date lowest plasma density of 3.2 × 1017 cm−3 are reported. The energy spectra of the generated electron beams exhibit good shot-to-shot reproducibility, with the observed variations attributable to the measured shot-to-shot jitter of the laser parameters. Two methods for correcting the effect of beam pointing variations on the measured energy spectrum are described.
Candida glabrata
has emerged as a major pathogen in invasive candidiasis in recent years. Currently, guidelines for invasive candidiasis treatment recommend fluconazole or an echinocandin as the ...first-line therapy. Nevertheless, the resistance of
Candida glabrata
to echinocandin is an emerging problem and has been partly associated with mutations in the
FKS1
and
FKS2
genes. The Etest® is an appropriate method for determining antifungal susceptibility in emergency routine diagnosis. In this work, we evaluated the reliability of the Etest® in comparison with the two reference broth microdilution methods, Clinical and Laboratory Standards Institute (CLSI) and European Committee on Antimicrobial Susceptibility Testing (EUCAST), to assess the caspofungin resistance of 193 isolates of
Candida glabrata
. The interpretation of minimum inhibitory concentration (MIC) values was also discussed according to different breakpoints. Moreover,
FKS1
and
FKS2
mutations were investigated for isolates with high MICs. Our results showed that the MIC
50
value was similar to the MIC
90
value for each method. The Etest® method showed the lowest MIC values, whereas EUCAST presented the highest. Categorical agreement between the Etest® and CLSI methods was 100 % and 36 % using the breakpoints proposed by Arendrup et al. (Antimicrob Agents Chemother 56(7):3965–3968,
2012
) and Pfaller et al. (Int J Antimicrob Agents 38(1):65–69,
2011
), respectively. Two isolates showed high MIC values with the three methods and both presented
FKS2
mutations. A novel
FKS2
mutation was also reported for one isolate. Future epidemiological studies should also evaluate the reliability of the Etest® to detect echinocandin resistance, as it remains a routine method.
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