Quasifree photoproduction of eta mesons off the neutron.

Quasifree photoproduction of eta mesons off nucleons bound in the deuteron has been measured with the CBELSA/TAPS detector for incident photon energies up to 2.5 GeV at the Bonn ELSA accelerator. The eta mesons have been detected in coincidence with recoil protons and recoil neutrons, which allows a detailed comparison of the quasifree n(gamma,eta)n and p(gamma,eta)p reactions. The excitation function for eta production off the neutron shows a pronounced bumplike structure at W=1.68 GeV (E{gamma} approximately 1 GeV), which is absent for the proton.

Modification of the omega-meson lifetime in nuclear matter.

Information on hadron properties in the nuclear medium has been derived from the photoproduction of omega mesons on the nuclei C, Ca, Nb, and Pb using the Crystal Barrel/TAPS detector at the ELSA tagged photon facility in Bonn. The dependence of the omega-meson cross section on the nuclear mass number has been compared with three different types of models: a Glauber analysis, a Boltzmann-Uehling-Uhlenbeck analysis of the Giessen theory group, and a calculation by the Valencia theory group. In all three cases, the inelastic omega width is found to be 130-150 MeV/c(2) at normal nuclear matter density for an average 3-momentum of 1.1 GeV/c. In the rest frame of the omega meson, this inelastic omega width corresponds to a reduction of the omega lifetime by a factor approximately 30. For the first time, the momentum dependent omegaN cross section has been extracted from the experiment and is in the range of 70 mb.

Observation of in-medium modifications of the omega meson.

The photoproduction of omega mesons on nuclei has been investigated using the Crystal Barrel/TAPS experiment at the ELSA tagged photon facility in Bonn. The aim is to study possible in-medium modifications of the omega meson via the reaction gamma + A --> omega + X --> pi(0)gamma + X('). Results obtained for Nb are compared to a reference measurement on a LH2 target. While for recoiling, long-lived mesons (pi(0), eta, and eta;(')), which decay outside of the nucleus, a difference in the line shape for the two data samples is not observed, we find a significant enhancement towards lower masses for omega mesons produced on the Nb target. For momenta less than 500 MeV/c an in-medium omega meson mass of M(medium) = [722(+4)(-4)(stat)+35-5(syst)] MeV/c(2) has been deduced at an estimated average nuclear density of 0.6rho(0).

Method development and validation of a high-performance liquid chromatographic method for pyrethrum extract.

A robust analytical methodology is developed for the quantitative determination of all six insecticidal components of pyrethrum extract: jasmolin I, cinerin I, pyrethrin I, jasmolin II, cinerin II, and pyrethrin II. This method, based on the separation technique normal-phase high-performance liquid chromatography, offers selectivity, accuracy, precision, linearity, range, ruggedness, and robustness as well as efficiency and ease.

Hierarchical color image region segmentation for content-based image retrieval system.

In this work, we propose a model of a content-based image retrieval system by using the new idea of combining a color segmentation with relationship trees and a corresponding tree-matching method. We retain the hierarchical relationship of the regions in an image during segmentation. Using the information of the relationships and features of the regions, we can represent the desired objects in images more accurately. In retrieval, we compare not only region features but also region relationships.

[Ileus caused by tuberculosis]. / Ileus durch Tuberkulose.

We report on a 30-year old patient suffering from acute abdomen. X-ray examinations (abdomen photograph, passage of contrast medium) showed an obstructive ileus of the small bowel. Exploratory laparatomy revealed an obstruction of the small bowel by means of masses of lymphatic nodes as part of a mesenteric lymphadenopathy. M. tuberculosis was identified as growing in cultures of peritoneal smears and material of lymphatic nodes. The retrospective examination of the pre-operative x-ray photographs of the chest showed an old primary complex of the lung. A combination of four antituberculotic drugs: Rifampicin, ethambutol, isoniazid and pyrazinamid was administered following the concept of a 6-month regimen. This treatment was successful: CT-scans of the abdomen showed a reduction of the mesenterial lymphadenopathy and the disappearance of the duodenal impression in the follow-up after 4 weeks of therapy. The abdominal TBC represents a severe disease requiring a differential diagnostic distinction from other abdominal diseases such as ileitis terminalis, Crohn's disease, neoplass as especially gastrointestinal lymphomas, giardiasis, amoebiasis and yersinia enterocolitis. The disease has a special importance among immigrant populations.

Rheumatoid nodules located in the penis of a methotrexate-treated patient with rheumatoid arthritis.

A case is reported in which a patient with a rheumatoid factor-negative rheumatoid arthritis developed rheumatoid nodules in the penis during treatment with methotrexate. The development of rheumatoid nodules in seronegative rheumatoid arthritis patients is extremely rare. An acceleration of rheumatoid nodules in methotrexate-treated rheumatoid arthritis patients is reported in literature. Regarding the case reported here, we propose a causal relationship between methotrexate-treatment and the development of rheumatoid nodules in our patient. Methotrexate should not be the preferential treatment for patients with rheumatoid arthritis developing rheumatoid nodules and suffering from vasculitis.

Elevated intravesical pressure causes arterial hypoperfusion in canine colocystoplasty: a fluorometric assessment.

Since 1988 there have been 15 reported cases of late, spontaneously ruptured intestinal cystoplasties at bowel sites remote from the anastomosis. Ischemic necrosis has been suggested as a possible etiology. We examined this hypothesis by quantifying the uptake of intravascular fluorescein in the augmented bowel of adult mongrel canines. There was a statistically significant decrease in fluorescein uptake at high intravesical pressures, which appeared to be most pronounced at the antimesenteric border. This laboratory study supports a recent clinical report of histological changes pathognomonic for chronic ischemia in the augmented bowel of patients with spontaneous rupture.