DSC investigations reveal several bonding states of EC at the Ag surface. If O-bridged by alkoxide or carboxylic links EC is strongly adsorbed. If other tightly bonded species are present at the surface, the adsorption of EC is weak. Competitive adsorption and solvent efficiency cause a high adsorbance from EA and a low one from terpineol solution.
Environmental sampling (ES) is one of the measures applied in international nuclear safeguards. The detection capability of
safeguards ES relies on a combination of highly sensitive analytical techniques and resourceful data evaluation. The evaluation
process is dynamic, employing a variety of tools, information and analytical results. While the presence of uranium or plutonium
may be a significant finding in itself, high quality isotopic measurements are essential to associate the material with a
specific nuclear activity. This is illustrated in cases where the uranium detected appears to be “natural” or “near-natural”,
but in fact can be identified with various nuclear processes.
Authors:A. Almási, Sz. Bojcsev, T. Fischer, H. Simon, P. Perjési, and Emil Fischer
The aim of these experiments was the investigation of the correlation between the metabolic enzyme activities and the intestinal and hepatic excretion of p-nitrophenol (PNP) and its metabolites (PNP-glucuronide: PNP-G and PNP-sulfate: PNP-S) in the same group of rats (n = 10). A jejunal loop was perfused with isotonic medium containing PNP in a concentration of 500 μM. The samples were obtained from the luminal perfusion medium and from the bile. For enzyme assays tissue samples were obtained from the liver and jejunum at the end of experiments. Significant differences were calculated by the Student’s t-test. The activity of UDP-glucuronyltransferase and sulfotransferase was about three times higher in the liver than in the small intestine. The activity of the ß-glucuronidase was about six times higher, the activity of the arylsulfatase was approximately seven times greater in the liver than in the jejunum. No significant difference was found between the luminal appearance and the biliary excretion of PNP-G. Contrary to these findings, the biliary excretion of PNP-S was significantly higher than the luminal appearance of PNP-sulfate. It can be concluded that no direct correlation exists between the activity of metabolic enzymes and the excretion rate of PNP-metabolites in the liver and in the jejunal segment of the small intestine.
Authors:Ch. Krueger, B. Gorski, A. Novgorodov, and S. Fischer
The selectivity of trioctylphosphineoxide /TOPO/ with respect to rare earths and sc was used to develop a single step separation method for43–48Sc from transition metals irradiated with high energy protons /660 MeV/. The target material serves as a salting-out agent in the described extraction-separation technique. Rapid and quantitative recovery of scandium is achieved using extraction chromatography. Radiochemically pure carrier-free Sc was separated from the following irradiated metals: Cr, Mn, Ni, Cu and Zn.
Authors:T. Lipovics, S. Czakó, I. Kelemen, and A. Fischer
A newly developed technique is presented to estimate site specific seismic failure frequencies of several types of storage tanks. Seismic failure is a failure event triggered by an earthquake leading to material release and serious damages. The present method is based on the convolution of site specific seismic hazard curves and component dependent fragility curves. Fragility curves are calculated with the help of probit coefficients originated from the analysis of historical data of earthquake damage. The calculation considers only the filling level, pressure and the damage state of storage tanks, and neglects the shape, volume, material and other parameters. Determination of seismic failure frequencies for storage tanks is done for three different Hungarian plant sites (Paks, Püspökszilágy, Csömör) using seismic hazard curves. In contrast of the simplifications the obtained frequency values represent a conservative estimation of failure frequencies triggered by earthquakes, and in comparison to international failure data the calculated values indicate significant frequencies. Therefore, the results imply that despite of the moderate seismic activity in Hungary, the effects of earthquakes on major-accident hazards should be considered in quantitative risk assessment.
Authors:S. Bojcsev, A. Almási, H. Simon, P. Perjési, and Emil Fischer
In the extrahepatic drug metabolism the intestinal tract can play an important role. These experiments were designed to study the biotransformation of p-nitrophenol (PNP) in the small intestine in the rat. Various segments of the small intestine (proximal and distal jejunum, terminal ileum) were perfused with isotonic solution in vivo containing different concentrations of PNP (20–100–500–1000 μM) and the concentrations of metabolites (PNP-G: p-nitrophenol glucuronide, PNP-S: p-nitrophenol sulfate) were determined in the perfusion medium. It was found a decreasing tendency in the glucuronidation from the proximal to distal segment of the small intestine: e.g. 430 nmol, 240 nmol, and 100 nmol PNP-G appeared in the perfusion medium in the proximal, distal jejunum and in the terminal ileum, respectively, when 500 μM PNP was luminally perfused for 90 minutes. Similar ratio was found at the luminal perfusion of other PNP-concentrations, too. Luminal appearance of sulfoconjugate of PNP was considerably lower and no clear gradient tendency in the formation of PNP-S could be detected in the small intestine from the proximal to distal segment. Our results show that there are considerable differences in drug metabolism in various segments of the small intestine. We have found a gradient conjugating activity from proximal to distal segment of small intestine in the glucuronidation of PNP.
Authors:M. Alutis, U. Grundmann, A. Fischer, A. Kühl, S. Bereswill, and M. Heimesaat
Increased levels of the matrix metalloproteinases-2 and -9 (also referred to gelatinase-A and -B, respectively) can be detected in intestinal inflammation. We have recently shown that selective gelatinase blockage by the synthetic compound RO28-2653 ameliorates acute murine ileitis and colitis. We here investigated whether RO28-2653 exerts anti-inflammatory effects in acute Campylobacter jejuni-induced enterocolitis of gnotobiotic IL-10−/− mice generated following antibiotic treatment. Mice were perorally infected with C. jejuni (day 0) and either treated with RO28-2653 (75 mg/kg body weight/day) or placebo from day 1 until day 6 post infection (p.i.) by gavage. Irrespective of the treatment, infected mice displayed comparable pathogen loads within the gastrointestinal tract. Following RO28-2653 administration, however, infected mice exhibited less severe symptoms such as bloody diarrhea as compared to placebo controls. Furthermore, less distinct apoptosis but higher numbers of proliferating cells could be detected in the colon of RO28-2653-treated as compared to placebo-treated mice at day 7 p.i. Remarkably, gelatinase blockage resulted in lower numbers of T- and B-lymphocytes as well as macrophages and monocytes in the colonic mucosa of C. jejuni-infected gnotobiotic IL-10−/− mice. Taken together, synthetic gelatinase inhibition exerts anti-inflammatory effects in experimental campylobacteriosis.
Authors:P. Batáry, A. Kovács-Hostyánszki, C. Fischer, T. Tscharntke, and A. Holzschuh
Hedges and forest edges play a major role in providing nesting sites, food resources and shelter for birds in agricultural landscapes of western and central Europe. We investigated the response of farmland vs. woodland birds at two degrees of isolation of hedges from forest and to vegetation structure. We surveyed 200 m long sections of six forest edges, six hedges connected to forests and six isolated hedges. Species richness and abundance of farmland birds were higher in hedges than in forest edges, species richness and abundance of woodland birds were lower in hedges than in the forest edges. Species richness and abundance of both groups did not differ between connected and isolated hedges. Width and height of hedges and edges did not affect the species richness and abundance of either farmland or woodland birds. Furthermore, bird community composition differed between habitat types (hedge vs. forest edge) and also between hedge isolation levels (hedges connected to forest vs. isolated hedges). Based on our results, we emphasize the importance of hedges in conserving farmland birds and encourage policy makers to support hedge creation and maintenance with landscape-wide management strategies supporting a diverse hedge structure. Both connected and isolated hedges play an important role as they harbour different bird communities.
Authors:B. Otto, L.-M. Haag, A. Fischer, R. Plickert, A. A. Kühl, U. B. Göbel, Markus M. Heimesaat, and S. Bereswill
Campylobacter jejuni is one of the predominant causes for foodborne bacterial infections worldwide. We investigated whether signaling of C. jejuni-lipoproteins and -lipooligosaccharide via Toll-like-receptor (TLR) -2 and -4, respectively, is inducing intestinal and extra-intestinal immune responses following infection of conventional IL-10-/- mice with chronic colitis. At day 3 following oral infection, IL-10-/- mice lacking TLR-2 or TLR-4 harbored comparable C. jejuni strain ATCC 43431 loads in their colon. Interestingly, infected TLR-4-/- IL-10-/- mice displayed less compromized epithelial barrier function as indicated by lower translocation rates of live gut commensals into mesenteric lymphnodes (MLNs), and exhibited less distinct B lymphocyte responses in their colonic mucosa as compared to naïve IL-10-/- controls. Furthermore, in extra-intestinal compartments such as MLNs and spleens, abundance of myeloid cells was less distinct whereas relative percentages of activated T helper cells and cytotoxic T cells were higher in spleens and dendritic cells more abundant in MLNs of infected IL-10-/- animals lacking TLR-4 as compared to IL-10-/- controls. Taken together, in conventionally colonized IL-10-/- mice, TLR-4, but not TLR-2, is involved in mediating extra-intestinal pro-inflammatory immune responses following C. jejuni infection. Thus, conventional IL-10-/- mice are well suited to further dissect mechanisms underlying Campylobacter infections in vivo.
Authors:S. Bereswill, A. Fischer, I. R. Dunay, A. A. Kühl, U. B. Göbel, O. Liesenfeld, and M. M. Heimesaat
Non-pathogenic Escherichia coli (Ec) strains K12 (EcK12) and Nissle 1917 (EcN) are used for gene technology and probiotic treatment of intestinal inflammation, respectively. We investigated intestinal colonization and potential pro-inflammatory properties of EcK12, EcN, and commensal E. coli (EcCo) strains in Toxoplasma (T.) gondii-induced acute ileitis. Whereas gnotobiotic animals generated by quintuple antibiotic treatment were protected from ileitis, mice replenished with conventional microbiota suffered from small intestinal necrosis 7 days post-T. gondii infection (p.i.). Irrespective of the Ec strain, recolonized mice revealed mild to moderate histopathological changes in their ileal mucosa. Upon stable recolonization with EcK12, EcN, or EcCo, development of inflammation was accompanied by pro-inflammatory responses at day 7 p.i., including increased ileal T lymphocyte and apoptotic cell numbers compared to T. gondii-infected gnotobiotic controls. Strikingly, either Ec strain was capable to translocate to extraintestinal locations, such as MLN, spleen, and liver. Taken together, Ec strains used in gene technology and probiotic treatment are able to exert inflammatory responses in a murine model of small intestinal inflammation. In conclusion, the therapeutic use of Ec strains in patients with broad-spectrum antibiotic treatment and/or intestinal inflammation should be considered with caution.