259 research outputs found
Measurements of scattering observables for the break-up reaction
High-precision measurements of the scattering observables such as cross
sections and analyzing powers for the proton-deuteron elastic and break-up
reactions have been performed at KVI in the last two decades and elsewhere to
investigate various aspects of the three-nucleon force (3NF) effects
simultaneously. In 2006 an experiment was performed to study these effects in
break-up reaction at 135 MeV with the detection system, Big
Instrument for Nuclear polarization Analysis, BINA. BINA covers almost the
entire kinematical phase space of the break-up reaction. The results are
interpreted with the help of state-of-the-art Faddeev calculations and are
partly presented in this contribution.Comment: Proceedings of 19th International IUPAP Conference on Few-Body
Problems in Physics, Bonn University, 31.08 - 05.09.2009, Bonn, GERMAN
Investigation of the quasi-free domain in deuteron-deuteron break-up using spin observables
Precision measurements of vector and tensor analyzing powers of the 2H(d, dp)n break-up process
for configurations in the vicinity of the quasi-free scattering regime with the neutron as spectator
are presented. These measurements are performed with a polarized deuteron-beam with an energy of
65MeV/nucleon impinging on a liquid-deuterium target. The experiment was conducted at the AGOR
facility at KVI using the BINA 4Ï€-detection system. Events for which the final-state deuteron and proton
are coplanar have been analyzed and the data have been sorted for various momenta of the missing
neutron. In the limit of vanishing neutron momentum and at large deuteron-proton momentum transfer,
the data agree well with the measured and theoretically predicted spin observables of the elastic deuteronproton
scattering process. The agreement deteriorates rapidly with increasing neutron momentum and/or
decreasing momentum transfer from the deuteron beam to the outgoing proton. This study reveals the
presence of a significant contribution of final-state interactions even at very small neutron momenta
Proton-deuteron radiative capture cross sections at intermediate energies
Differential cross sections of the reaction have been
measured at deuteron laboratory energies of 110, 133 and 180 MeV. The data were
obtained with a coincidence setup measuring both the outgoing He and the
photon. The data are compared with modern calculations including all possible
meson-exchange currents and two- and three- nucleon forces in the potential.
The data clearly show a preference for one of the models, although the shape of
the angular distribution cannot be reproduced by any of the presented models.Comment: 6 pages, 6 figures, accepted for publication in EPJ
Comprehensive measurements of cross sections and spin observables of the three-body break-up channel in deuteron-deuteron scattering at 65 MeV/nucleon
Detailed measurements of five-fold differential cross sections and a rich set
of vector and tensor analyzing powers of the 2H(d; dp)n break-up process using
polarized deuteron-beam energy of 65 MeV/nucleon with a liquid-deuterium target
are presented. The experiment was conducted at the AGOR facility at KVI using
the BINA 4Pi-detection system. We discuss the analysis procedure including a
thorough study of the systematic uncertainties. The results can be used to
examine upcoming state-of-the-art calculations in the four-nucleon scattering
domain, and will, thereby, provide further insights into the dynamics of three-
and four-nucleon forces in few-nucleon systems. The results of coplanar
configurations are compared with the results of recent theoretical calculations
based on the Single-Scattering Approximation (SSA). Through these comparisons,
the validity of SSA approximation is investigated in the Quasi-Free (QF)
region.Comment: 33 pages, 30 figure
Cross Sections of the Deuteron-Proton Breakup at 130 MeV:A Probe of Three-Nucleon System Dynamics
Three-nucleon system dynamics can be investigated quantitatively by comparing observables calculated with the use of Faddeev equations with results of precise measurements. Proper description of the experimental data can be achieved only if the dynamical models include, in addition to the nucleon-nucleon interaction, subtle effects of suppressed degrees of freedom, effectively introduced by means of genuine three-nucleon forces. A large set of high precision, exclusive cross-section data for the (1)H(d,pp)n breakup reaction at 130 MeV contributes significantly to constrain the physical assumptions underlying the theoretical interaction models. Comparison of nearly 1,800 cross section data points with the predictions using nuclear interactions generated in various ways, allowed to establish importance of including both, the three-nucleon and the Coulomb forces to significantly improve the description of the whole data set
Elastic proton-deuteron scattering at intermediate energies
Observables in elastic proton-deuteron scattering are sensitive probes of the
nucleon-nucleon interaction and three-nucleon force effects. The present
experimental data base for this reaction is large, but contains a large
discrepancy between data sets for the differential cross section taken at 135
MeV/nucleon by two experimental research groups. This paper reviews the
background of this problem and presents new data taken at KVI. Differential
cross sections and analyzing powers for the and
reactions at 135 MeV/nucleon and 65 MeV/nucleon,
respectively, have been measured. The data differ significantly from previous
measurements and consistently follow the energy dependence as expected from an
interpolation of published data taken over a large range at intermediate
energies.Comment: 5 pages, 4 figures, submitted to PR
Molecular analysis of human endometrium: short-term tibolone signaling differs significantly from estrogen and estrogen + progestagen signaling
Tibolone, a tissue-selective compound with a combination of estrogenic, progestagenic, and androgenic properties, is used as an alternative for estrogen or estrogen plus progesterone hormone therapy for the treatment of symptoms associated with menopause and osteoporosis. The current study compares the endometrial gene expression profiles after short-term (21Â days) treatment with tibolone to the profiles after treatment with estradiol-only (E2) and E2 + medroxyprogesterone acetate (E2 + MPA) in healthy postmenopausal women undergoing hysterectomy for endometrial prolapse. The impact of E2 treatment on endometrial gene expression (799 genes) was much higher than the effect of tibolone (173 genes) or E2 + MPA treatment (174 genes). Furthermore, endometrial gene expression profiles after tibolone treatment show a weak similarity to the profiles after E2 treatment (overlap 72 genes) and even less profile similarity to E2 + MPA treatment (overlap 17 genes). Interestingly, 95 tibolone-specific genes were identified. Translation of profile similarity into biological processes and pathways showed that ER-mediated downstream processes, such as cell cycle and cell proliferation, are not affected by E2 + MPA, slightly by tibolone, but are significantly affected by E2. In conclusion, tibolone treatment results in a tibolone-specific gene expression profile in the human endometrium, which shares only limited resemblance to E2 and even less resemblance to E2 + MPA induced profiles
Allergic lung inflammation alters neither susceptibility to Streptococcus pneumoniae infection nor inducibility of innate resistance in mice
<p>Abstract</p> <p>Background</p> <p>Protective host responses to respiratory pathogens are typically characterized by inflammation. However, lung inflammation is not always protective and it may even become deleterious to the host. We have recently reported substantial protection against <it>Streptococcus pneumoniae </it>(pneumococcal) pneumonia by induction of a robust inflammatory innate immune response to an inhaled bacterial lysate. Conversely, the allergic inflammation associated with asthma has been proposed to promote susceptibility to pneumococcal disease. This study sought to determine whether preexisting allergic lung inflammation influences the progression of pneumococcal pneumonia or reduces the inducibilty of protective innate immunity against bacteria.</p> <p>Methods</p> <p>To compare the effect of different inflammatory and secretory stimuli on defense against pneumonia, intraperitoneally ovalbumin-sensitized mice were challenged with inhaled pneumococci following exposure to various inhaled combinations of ovalbumin, ATP, and/or a bacterial lysate. Thus, allergic inflammation, mucin degranulation and/or stimulated innate resistance were induced prior to the infectious challenge. Pathogen killing was evaluated by assessing bacterial CFUs of lung homogenates immediately after infection, the inflammatory response to the different conditions was evaluated by measurement of cell counts of bronchoalveolar lavage fluid 18 hours after challenge, and mouse survival was assessed after seven days.</p> <p>Results</p> <p>We found no differences in survival of mice with and without allergic inflammation, nor did the induction of mucin degranulation alter survival. As we have found previously, mice treated with the bacterial lysate demonstrated substantially increased survival at seven days, and this was not altered by the presence of allergic inflammation or mucin degranulation. Allergic inflammation was associated with predominantly eosinophilic infiltration, whereas the lysate-induced response was primarily neutrophilic. The presence of allergic inflammation did not significantly alter the neutrophilic response to the lysate, and did not affect the induced bacterial killing within the lungs.</p> <p>Conclusion</p> <p>These results suggest that allergic airway inflammation neither promotes nor inhibits progression of pneumococcal lung infection in mice, nor does it influence the successful induction of stimulated innate resistance to bacteria.</p
Investigation of the Three-Nucleon System Dynamics in the Deuteron-Proton Breakup Reaction
Precise and large sets of cross section, vector A x , A y and tensor A xx , A xy , A yy analyzing power data for the 1 H(d, pp)n breakup reactions were measured at 100 and 130 MeV deuteron beam energies with the SALAD and BINA detectors at KVI and the Germanium Wall setup at FZ-Jülich. Results are compared with various theoretical approaches which model the three-nucleon system dynamics. The cross section data reveal a sizable three-nucleon force (3NF) and Coulomb force influence. In case of the analyzing powers very low sensitivity to these effects was found and the data are well describe by 2N models only. For A xy at 130 MeV, serious disagreements were observed when 3NF models are included in the calculations
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