Search results for "Radioisotope"

Numerical dating of the Eckfeld maar fossil site, Eifel, Germany: a calibration mark for the Eocene time scale.

2000

Sediments of the Eckfeld maar (Eifel, Germany) bear a well-preserved Eocene fauna and flora. Biostratigraphically, Eckfeld corresponds to the Middle Eocene mammal reference level MP (Mammals Paleogene) 13 of the ELMA (European Land Mammal Age) Geiseltalian. In the maar crater, basalt fragments were drilled, representing explosion crater eruption products. By 40Ar/39Ar dating of the basalt, for the first time a direct numerical calibration mark for an Eocene European mammal locality has been established. The Eckfeld basalt inverse isochron date of 44.3 +/- 0.4 Ma suggests an age for the Geiseltalian/Robiacian boundary at 44 Ma and, together with the 1995 time scale of Berggren et al., a time…

One-pot, direct incorporation of [11C]CO2 into carbamates.

2009

Why beat about the bush? An operationally simple and mild reaction based on the direct fixation of (11)CO(2) with 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) has been developed for the synthesis of (11)C-labeled carbamates at 75 degrees C within 10 minutes in radiochemical yields above 70% (see scheme). This strategy should be immediately useful for the construction of new radiotracers for positron emission tomography and other applications.

A simple, rapid method for the preparation of [11C]formaldehyde **

2008

Mapping of the high molecular weight kininogen binding site of prekallikrein. Evidence for a discontinuous epitope formed by distinct segments of the…

1993

Prekallikrein, a glycoprotein involved in contact phase activation, circulates in plasma in the form of a binary complex with high molecular weight kininogen (H-kininogen). The binding to H-kininogen is mediated by the prekallikrein heavy chain consisting of four repetitive domains, A1-A4. To define more precisely the region(s) involved in kininogen binding, we have employed an affinity cross-linking strategy with a synthetic peptide of 31 residues which mimics the prekallikrein binding site of H-kininogen. Cross-linking of the radiolabeled peptide to (pre)kallikrein revealed a binding segment in the NH2-terminal portion of the prekallikrein heavy chain; another binding segment was located …

Yttrium and lanthanides in human lung fluids, probing the exposure to atmospheric fallout.

2011

International audience; Inhalation of airborne particles can produce crystallization of phosphatic microcrysts in intraaveolar areas of lungs, sometimes degenerating into pulmonary fibrosis. Results of this study indicate that these pathologies are induced by interactions between lung fluids and inhaled atmospheric dust in people exposed to volcanic dust ejected from Mount Etna in 2001. Here, the lung solid-liquid interaction is evaluated by the distribution of yttrium and lanthanides (YLn) in fluid bronchoalveolar lavages on selected individuals according the classical geochemical approaches. We found that shale-normalised patterns of yttrium and lanthanides have a 'V shaped' feature corre…

Production and Radiochemical Separation of the Auger Electron Emitter140Nd

2000

Among the Auger electron emitters, the radiolanthanide 140Nd has some unique nuclear properties with potential for endoradiotherapeutic applications. In the present study, 140Nd was produced via the 140Ce(3He,3n) nuclear process at the FZ Julich CV28 cyclotron, irradiating CeO2 with 3He particles of 36 MeV primary energy. Yields of about 5 MBq 140Nd per microAh were experimentally obtained. Batch yields of > 100 MBq 140Nd were reached. 140Nd was separated in 75 +/- 5% radiochemical yield using a two-step process, first by extracting the bulk of the target material according to a Ce(IV)/Nd(III) separation, then by final ion exchange purification.

Dual Labeling of Lipopolysaccharides for SPECT-CT Imaging and Fluorescence Microscopy.

2013

International audience; : Lipopolysaccharides (LPS) or endotoxins are amphipathic, pro-inflammatory components of the outer membrane of Gram-negative bacteria. In the host, LPS can trigger a systemic inflammatory response syndrome. To bring insight into in vivo tissue distribution and cellular uptake of LPS, dual labeling was performed with a bimodal molecular probe designed for fluorescence and nuclear imaging. LPS were labeled with DOTA-Bodipy-NCS, and pro-inflammatory properties were controlled after each labeling step. LPS were then radiolabeled with (111)In and subsequently injected intravenously into wild-type, C57B16 mice, and their in vivo behavior was followed by single photon emis…

Gamma activity and geochemical features of building materials: estimation of gamma dose rate and indoor radon levels in Sicily.

2001

A high-purity germanium detector has been used to measure the abundance of radium (Ra), thorium (Th) and potassium (K) in building materials used in Sicilian dwellings. The measurements were performed to evaluate which material was suitable for the construction of an enclosure, which would have a low background emission. The materials examined in this work showed concentrations of 226Ra, 232Th and 40K dramatically variable depending on the lithologies, particularly in the case of blocks, sands and aggregates commonly used in building materials in Sicily. The results are discussed and a criterion is indicated to reduce the radiation dose to humans. Since radon inlet is a major health problem…

The synthesis of SNAT2 transporters is required for the hypertonic stimulation of system A transport activity

2004

AbstractIn cultured human fibroblasts incubated under hypertonic conditions, the stimulation of system A for neutral amino acid transport, associated to the increased expression of the mRNA for SNAT2 transporter, leads to an expanded intracellular amino acid pool and to the recovery of cell volume. A protein of nearly 60 kDa, recognized by an antiserum against SNAT2, is increased both in the pool of biotinylated membrane proteins and in the total cell lysate of hypertonically stressed cells. The increased level of SNAT2 transporters in hypertonically stressed cells is confirmed by immunocytochemistry. DRB, an inhibitor of transcription, substantially inhibits the increase of SNAT2 proteins …

Initial results of NEXT-DEMO, a large-scale prototype of the NEXT-100 experiment

2013

NEXT-DEMO is a large-scale prototype of the NEXT-100 detector, an electroluminescent time projection chamber that will search for the neutrinoless double beta decay of Xe-136 using 100-150 kg of enriched xenon gas. NEXT-DEMO was built to prove the expected performance of NEXT-100, namely, energy resolution better than 1% FWHM at 2.5MeV and event topological reconstruction. In this paper we describe the prototype and its initial results. A resolution of 1.75% FWHM at 511 keV (which extrapolates to 0.8% FWHM at 2.5 MeV) was obtained at 10 bar pressure using a gamma-ray calibration source. Also, a basic study of the event topology along the longitudinal coordinate is presented, proving that it…