639 research outputs found
Detection of Pseudomonas aeruginosa in sputum samples by modified fluorescent in situ hybridization
Pseudomonas aeruginosa is the most common and dominant infectious agent that causes chronic pneumonia in patients with cystic fibrosis (CF). Fluorescent in situ hybridization (FISH) is a powerfulmolecular method for the specific and rapid diagnosis of bacteria, including the detection of P. aeruginosa in sputum samples from CF patients. High background fluorescence of viscous sputumsamples obtained from CF patients may impede detection of microorganisms by FISH. The aim of this study was to test the application of biotin during FISH technique to reduce unspecific background fluorescence in sputum samples to facilitate and improve detection of P. aeruginosa. Sixty-three sputum samples from CF patients were tested by FISH to detect P. aeruginosa. All the 63 samples were also examined by a modified FISH procedure including biotin treatment. The FISH results were compared with those of conventional culture method. The specificity of FISH was 100%. The sensitivity of FISH for detection of P. aeruginosa from samples without biotin treatment was 83.3%, whereas in biotin-treated samples was 88.1%. Biotin reduced background fluorescence of 12 sputum samples of CF patients and it did not show any adverse effect on FISH results of the remaining sputum samples. Therefore, using of biotin in FISH procedure seems to facilitate and improve the detection of respiratorytract infections by P. aeruginosa in this population
Extracting the depolarization coefficient D_NN from data measured with a full acceptance detector
The spin transfer from vertically polarized beam protons to Lambda or Sigma
hyperons of the associated strangeness production pp -> pK Lambda (Sigma) is
described with the depolarization coefficient D_NN. As the polarization of the
hyperons is determined by their weak decays, detectors, which have a large
acceptance for the decay particles, are needed. In this paper a formula is
derived, which describes the depolarization coefficient D_NN by count rates of
a 4 pi detector. It is shown, that formulas, which are given in publications
for detectors with restricted acceptance, are specific cases of this formula
for a 4 pi detector.Comment: Accepted for publication by Nuclear Instruments and Methods in
Physics Research Section
Mikrostruktura wygrzewanych pokryć cynkowych typu galfan na podłożu stalowym
The commercially available Galfan coating containing 5-7wt.% of Al deposited on the low carbon steel substrate by
hot dipping has been examined with respect to the microstructure of the coating/substrate interface area. The application of
several experimental techniques (SEM/EDS, XRD, TEM/AEM/EDS/ED) allowed demonstrating the two-phase structure of the
alloy coating in non-treated, commercially available Galfan samples: Zn-rich pre-eutectoid phase grains are surrounded by
lamellar eutectics of -Al and -Zn. The transition layer between the alloy coating and steel substrate with the considerably
higher Al content (SEM/EDS, TEM/EDS) has been found in both non-treated and annealed samples (600oC/5 minutes). Only
the monoclinic FeAl3Znx phase however was revealed in the annealed sample (TEM/electron diffraction) remaining uncertain
the presence of the orthorhombic Fe2Al5Znx phase, reported by several authors
Determination of the eta'-proton scattering length in free space
Taking advantage of both the high mass resolution of the COSY-11 detector and
the high energy resolution of the low-emittance proton-beam of the Cooler
Synchrotron COSY we determine the excitation function for the pp --> pp eta'
reaction close-to-threshold. Combining these data with previous results we
extract the scattering length for the eta'-proton potential in free space to be
Re(a_{p eta'}) = 0+-0.43 fm and Im(a_{p eta'}) = 0.37(+0.40)(-0.16) fm.Comment: 5 pages, 3 figures, accepted for publication in Phys. Rev. Let
A recoil detector for the measurement of antiproton-proton elastic scattering at angles close to 90
The design and construction of a recoil detector for the measurement of
recoil protons of antiproton-proton elastic scattering at scattering angles
close to 90 are described. The performance of the recoil detector has
been tested in the laboratory with radioactive sources and at COSY with proton
beams by measuring proton-proton elastic scattering. The results of laboratory
tests and commissioning with beam are presented. Excellent energy resolution
and proper working performance of the recoil detector validate the conceptual
design of the KOALA experiment at HESR to provide the cross section data needed
to achieve a precise luminosity determination at the PANDA experiment.Comment: 10 pages, 15 figure
Novel Polymorph of GaSe
2D GaSe is a semiconductor belonging to the group of post-transition metal chalcogenides with great potential for advanced optoelectronic applications. The weak interlayer interaction in multilayer 2D materials allows the formation of several polymorphs. Here, the first structural observation of a new GaSe polymorph is reported, characterized by a distinct atomic configuration with a centrosymmetric monolayer (D-3d point group). The atomic structure of this new GaSe polymorph is determined by aberration-corrected scanning transmission electron microscopy. Density-functional theory calculations verify the structural stability of this polymorph. Furthermore, the band structure and Raman intensities are calculated, predicting slight differences to the currently known polymorphs. In addition, the occurrence of layer rotations, interlayer relative orientations, as well as translation shear faults is discussed. The experimental confirmation of the new GaSe polymorph indicates the importance of investigating changes in the crystal structure, which can further impact the properties of this family of compoundsThis article has received support from the project Nanotechnology Based Functional Solutions (NORTE-01-0145-FEDER-000019), supported by Norte Portugal Regional Operational Programme (NORTE2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF). Additional support by National Funds through the Portuguese Foundation for Science and Technology (FCT) in the framework of the project "LA2D" -PTDC/FIS-NAN/3668/2014 is acknowledged. This work was supported by FCT, through IDMEC, under LAETA, project UIDB/50022/2020. A. M.-S. thanks the Marie-Curie-COFUND program Nano TRAIN for Growth II (Grant Agreement 713640) and the Ramon y Cajal programme (grant RYC2018-024024-I, MINECO, Spain). This work was carried out in part through the use of the INL Advanced Electron Microscopy, Imaging, and Spectroscopy Facility. The computations were performed on the Tirant III cluster of the Servei d'Informatica of the University of Valencia (project vlc82) and on Mare Nostrum cluster of the Barcelona Supercomputing Center (project FI-2020-2-033 and FI-2020-3-0021)
Determination of the total width of the eta' meson
Taking advantage of both the low-emittance proton-beam of the Cooler
Synchrotron COSY and the high momentum precision of the COSY-11 detector
system, the mass distribution of the eta' meson was measured with a resolution
of 0.33 MeV/c^2 (FWHM), improving the experimental mass resolution by almost an
order of magnitude with respect to previous results. Based on the sample of
more than 2300 reconstructed pp --> pp eta' events the total width of the eta'
meson was determined to be 0.226 +- 0.017(stat.) +- 0.014(syst.) MeV/c^2.Comment: 4 pages, 4 figure
Search for the 3He-eta bound state at COSY-11
We have measured excitation function for dp -> ppp_pi- reaction near the eta
production threshold. We observe an enhancement of the counting rate above the
threshold which can originate from the production of the eta meson in the
reaction dp -> 3He eta and its subsequent absorption on neutron in the 3He
nucleus leading to creation of the p_pi- pair.Comment: Presented at 10th International Workshop on Meson Production,
Properties and Interaction (MESON 2008), Cracow, Poland, 6 - 10 June 2008, 4
pages, 4 figures,references adde
Deposition of Al2O3-TiO2 Nanostructured Powders by Atmospheric Plasma Spraying
Al2O3-13%TiO2 coatings were deposited on stainless steel substrates from conventional and nanostructured
powders using atmospheric plasma spraying (APS). A complete characterization of the
feedstock confirmed its nanostructured nature. Coating microstructures and phase compositions were
characterized using SEM, TEM, and XRD techniques. The microstructure comprised two clearly differentiated
regions. One region, completely fused, consisted mainly of nanometer-sized grains of c-Al2O3
with dissolved Ti+4. The other region, partly fused, retained the microstructure of the starting powder
and was principally made up of submicrometer-sized grains of a-Al2O3, as confirmed by TEM. Coating
microhardness as well as tribological behavior were determined. Vickers microhardness values of conventional
coatings were in average slightly lower than the values for nanostructured coating. The wear
resistance of conventional coatings was shown to be lower than that of nanostructured coatings as a
consequence of Ti segregation. A correlation between the final properties, the coating microstructure,
and the feedstock characteristics is give
- …