530 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
One-Particle Measurement of the Antiproton Magnetic Moment
\DeclareRobustCommand{\pbar}{\HepAntiParticle{p}{}{}\xspace}
\DeclareRobustCommand{\p}{\HepParticle{p}{}{}\xspace}
\DeclareRobustCommand{\mup}{{}{}\xspace}
\DeclareRobustCommand{\mupbar}{\mu_{\pbar}{}{}\xspace}
\DeclareRobustCommand{\muN}{{}{}\xspace
For the first time a single trapped \pbar is used to measure the \pbar
magnetic moment {\bm\mu}_{\pbar}. The moment {\bm\mu}_{\pbar} = \mu_{\pbar}
{\bm S}/(\hbar/2) is given in terms of its spin and the nuclear
magneton (\muN) by \mu_{\pbar}/\mu_N = -2.792\,845 \pm 0.000\,012. The 4.4
parts per million (ppm) uncertainty is 680 times smaller than previously
realized. Comparing to the proton moment measured using the same method and
trap electrodes gives \mu_{\pbar}/\mu_p = -1.000\,000 \pm 0.000\,005 to 5
ppm, for a proton moment ,
consistent with the prediction of the CPT theorem.Comment: 4 pages, 4 figures. arXiv admin note: substantial text overlap with
arXiv:1201.303
Low-Energy \Lambda-\p Scattering Parameters from the Reaction
Constraints on the spin-averaged scattering length and effective
range have been obtained from measurements of the reaction
close to the production threshold by comparing model phase-space Dalitz plot
occupations with experimental ones. The data fix well the position of the
virtual bound state in the system. Combining this with information
from elastic scattering measurements at slightly higher energies,
together with the fact that the hyperdeuteron is not bound, leads to a new
determination of the low energy scattering parameters.Comment: 18 pages, 7 figure
Heavy Meson Production at COSY - 11
The COSY-11 collaboration has measured the total cross section for the pp -->
pp eta-prime and pp --> pp eta reactions in the excess energy range from
Q = 1.5 MeV to Q = 23.6 MeV and from Q = 0.5 MeV to Q = 5.4 MeV,
respectively.
Measurements have been performed with the total luminosity of 73 nb^(-1) for
the pp --> pp eta reaction and 1360 nb^(-1) for the pp --> pp eta-prime one.
Recent results are presented and discussed.Comment: Invited talk at 4th International Conference on Physics at Storage
Rings (STORI 99), Bloomington, Indiana, USA, September 12-16, 199
Experimental results on strangeness production in proton-proton collisions at COSY
The production of K+ and K- mesons in elementary proton-proton collision has
been investigated at the Cooler Synchrotron COSY in Juelich. A high quality
proton beam with low emittance and small momentum spread permitted to study the
creation of these mesons very close to the kinematical threshold. The energy
dependence of the total cross section is investigated using internal beam
facilities providing a high accuracy particle momentum determination as well as
an external non-magnetic detection setup with a large geometrical acceptance.
The determination of the four-momentum vectors for all ejectiles of each
registered event gives the complete kinematical information allowing to study
the interaction of the outgoing particles. Results on the performed studies of
the pp --> pp K+ K-, pp --> p Lambda K+ and pp --> p Sigma0 K+ reactions will
be presented and their relevance to the interpretation of heavy ion collisions
will be discussed.Comment: 8 pages, 6 figures, plenary talk at 6th International Conference On
Strange Quarks in Matter: '2001 - A Flavorspace Odyssey' (SQM2001),
Frankfurt, Germany, September 25-29, 2001, to be published in J. Phys. G:
Nucl. Part. Phy
Total and Differential Cross Sections for the pp-->pp eta-prime Reaction Near Threshold
The eta-prime meson production in the reaction pp-->pp eta-prime has been
studied at excess energies of Q = 26.5, 32.5 and 46.6 MeV using the internal
beam facility COSY-11 at the cooler synchrotron COSY. The total cross sections
as well as one angular distribution for the highest Q-value are presented. The
excitation function of the near threshold data can be described by a pure
s-wave phase space distribution with the inclusion of the proton-proton final
state interaction and Coulomb effects. The obtained angular distribution of the
eta-prime mesons is also consistent with pure s-wave production.Comment: 6 pages, 5 figures, submitted to Eur. Phys. J.
General thoughts to the Kaon pair production in the threshold region
Simple--minded thoughts about the cross sections for the reactions
pp-->ppK+K- and pp-->ppK0K0 are presented, which certainly do not account for
the complex coupled channel problem but rather provide some ideas into the
mutual reaction dynamics.Comment: Talk given at 9th International Workshop on Meson Production,
Properties and Interaction, Cracow, Poland, 9-13 June 2006. 3 pages, 2
figure
Comparison of Strangeness Production between A+A and p+p Reactions from 2 to 160 AGeV
The measured K ratios from heavy-ion reactions are compared with
the K ratios from p+p reactions over the energy range 2-160 AGeV. The
K/ enhancement in heavy-ion reactions is largest at the lower energies,
consistent with strangeness production in secondary scattering becoming
relatively more important than initial collisions near the kaon production
threshold. The enhancement decreases steadily from 4 to 160 AGeV, suggesting
that the same enhancement mechanism of hadronic rescattering and decay of
strings may be applicable over this full energy range. Based on existing data,
the mid-rapidity K ratio is predicted to be for the
forthcoming Pb+Pb reactions at 40 AGeV/c.Comment: 14 pages, 4 figures, submitted to Phys. Rev.
COSY-11: an experimental facility for studying meson production in free and quasi-free nucleon-nucleon collisions
The COSY-11 experimental setup is an internal facility installed at the
COoler SYnchrotron COSY in Juelich. It allows to investigate meson production
in free and quasi-free nucleon-nucleon collisions, eg. pp --> pp meson and pd
--> p_sp np meson reactions. Drift chambers and scintillators permit to measure
outgoing protons, separated in magnetic field of COSY-11 dipole. Neutrons are
registered in the neutron modular detector installed downstream the beam.
Recently, the experimental setup has been extended with spectator detector,
deuteron drift chamber and polarization monitoring system, and since then meson
production can be investigated also as a function of spin and isospin of
colliding nucleons.Comment: Presented at LEAP05: International conference on Low Energy
Antiproton Physics, Bonn - Juelich, Germany, May 16-22, 200
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