Accurate detection of carbapenemase-producing glucose-nonfermenting Gram-negative bacilli (CPNFs), including
and
, is necessary to prevent their dissemination within health care settings. We ...performed a method comparison study of 11 phenotypic carbapenemase detection assays to evaluate their accuracy for the detection of CPNFs. A total of 96 carbapenem-resistant glucose-nonfermenting isolates were included, of which 29% produced carbapenemases. All CPNFs were molecularly characterized to identify β-lactamase genes. A total of 86% of the carbapenemase-producing
isolates produced class B carbapenemases. Several assays performed with a sensitivity of >90% for the detection of carbapenemase-producing
, including all rapid chromogenic assays and the modified carbapenem inactivation method. Most included assays, with the exception of the Manual Blue Carba assay, the Modified Carba NP assay, the boronic acid synergy test, and the metallo-β-lactamase Etest, had specificities of >90% for detecting carbapenemase-producing
Class D carbapenemases were the most prevalent carbapenemases among the carbapenemase-producing
strains, with 60% of the carbapenemase-producing
isolates producing acquired OXA-type carbapenemases. Although several assays achieved >90% specificity in identifying carbapenemase-producing
, no assays achieved a sensitivity of greater than 90%. Our findings suggest that the available phenotypic tests generally appear to have excellent sensitivity and specificity for detecting carbapenemase-producing
isolates. However, further modifications to existing assays or novel assays may be necessary to accurately detect carbapenemase-producing
.
Black Silicon Photovoltaics Otto, Martin; Algasinger, Michael; Branz, Howard ...
Advanced optical materials,
February 2015, Letnik:
3, Številka:
2
Journal Article
This article presents an overview of the fabrication methods of black silicon, their resulting morphologies, and a quantitative comparison of their optoelectronic properties. To perform this ...quantitative comparison, different groups working on black silicon solar cells have cooperated for this study. The optical absorption and the minority carrier lifetime are used as benchmark parameters. The differences in the fabrication processes plasma etching, chemical etching, or laser processing are discussed and compared with numerical models. Guidelines to optimize the relevant physical parameters, such as the correlation length, optimal height of the nanostructures, and the surface defect densities for optoelectronic applications are given.
Black Silicon is a class of sub‐micrometer stochatistically structured silicon surface with extremely high optical absorbtion. The optoelectronic properties of black silicon fabricated by different methods are reviewed and guidelines to optimize the relevant physical parameters are given.
Correct identification and classification of sponges is challenging due to ambiguous or misleading morphological features. A particular case is a blue keratose sponge occasionally referred to as the ..."Blue Photo Sponge" among aquarists, which appears frequently (and in several cases unintended) in private aquaria. This spicule-less species, occasionally specified as
Bergquist, Cambie & Kernan 1990, not only displays a high phenotypic plasticity in growth form and colour, it also proliferates in aquacultures under standard conditions unlike most other sponges. Therefore, this species is regarded as a pest for most aquarists. In turn, the ease of cultivation and propagation in aquacultures qualifies this species as a model organism for a wide array of scientific applications. For these purposes, correct identification and classification are indispensable. We reconstructed ribosomal gene trees and determined this species as
(De Laubenfels, 1954) (Phyllospongiinae), distant to
, and corroborated by skeletal features. Additionally, the resulting phylogeny corroborated major shortcomings of the current Phyllospongiinae classification-its consequences are discussed.
The reconstruction of the signal from hadrons and jets emerging from the proton–proton collisions at the Large Hadron Collider (LHC) and entering the ATLAS calorimeters is based on a ...three-dimensional topological clustering of individual calorimeter cell signals. The cluster formation follows cell signal-significance patterns generated by electromagnetic and hadronic showers. In this, the clustering algorithm implicitly performs a topological noise suppression by removing cells with insignificant signals which are not in close proximity to cells with significant signals. The resulting
topological cell clusters
have shape and location information, which is exploited to apply a local energy calibration and corrections depending on the nature of the cluster. Topological cell clustering is established as a well-performing calorimeter signal definition for jet and missing transverse momentum reconstruction in ATLAS.
Microorganisms rarely occur as individual cells in nature and are, instead, organized in complex multicellular communities such as colonies, fruiting bodies, or biofilms. Interest in the natural ...microbial life-style has increased during the last decade and a whole plethora of techniques has been used to gain insight into the development, structure and composition of diverse microbial communities. We have developed a technique for investigating the spatial heterogeneity of microbial growth in macro-colonies which essentially entails excision of the colonies with the underlying agar, freezing and subsequent cryotoming of the colonies, then FTIR microspectroscopic mapping of the cryosections. Colonies from Legionella, Bacillus, and Candida strains were chosen as model systems of multi-cellular communities to evaluate the technique. The results obtained indicate pronounced cell population heterogeneity even in relatively young colonies cultivated under laboratory conditions. Spectral data obtained from different positions within, e.g., a colony of Legionella bozemanii 120 h old indicated that levels of the storage material poly-β-hydroxybutyric acid were significantly higher in cells at the surface of the colonies than in those growing at the bottom next to the agar surface. Similarly, in a 24-h-old macro-colony of Bacillus megaterium significantly more of the capsular compound polyglutamic acid was detected in upper layers than in deeper layers of the colony. Results demonstrate that FTIR microspectroscopy can be an useful tool for investigation of the spatial heterogeneity of cell growth within microbial macro-colonies. It is suggested that the method also can be adapted to the analysis of more complex multicellular communities, for example fruiting bodies, biofilms, or colonies growing under natural conditions.
This paper presents the performance of the ATLAS muon reconstruction during the LHC run with
p
p
collisions at
s
=
7
–8 TeV in 2011–2012, focusing mainly on data collected in 2012. Measurements of ...the reconstruction efficiency and of the momentum scale and resolution, based on large reference samples of
J
/
ψ
→
μ
μ
,
Z
→
μ
μ
and
Υ
→
μ
μ
decays, are presented and compared to Monte Carlo simulations. Corrections to the simulation, to be used in physics analysis, are provided. Over most of the covered phase space (muon
|
η
|
<
2.7
and
5
≲
p
T
≲
100
GeV) the efficiency is above
99
%
and is measured with per-mille precision. The momentum resolution ranges from
1.7
%
at central rapidity and for transverse momentum
p
T
≃
10
GeV, to
4
%
at large rapidity and
p
T
≃
100
GeV. The momentum scale is known with an uncertainty of
0.05
%
to
0.2
%
depending on rapidity. A method for the recovery of final state radiation from the muons is also presented.
Proton–proton collisions at
TeV and heavy ion collisions at
TeV were produced by the LHC and recorded using the ATLAS experiment’s trigger system in 2010. The LHC is designed with a maximum bunch ...crossing rate of 40 MHz and the ATLAS trigger system is designed to record approximately 200 of these per second. The trigger system selects events by rapidly identifying signatures of muon, electron, photon, tau lepton, jet, and
B
meson candidates, as well as using global event signatures, such as missing transverse energy. An overview of the ATLAS trigger system, the evolution of the system during 2010 and the performance of the trigger system components and selections based on the 2010 collision data are shown. A brief outline of plans for the trigger system in 2011 is presented.
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