Search Results - (Author, Cooperation:A. Schroeter)

2011-10-25

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

Algorithms ; Amino Acid Motifs ; Amino Acid Sequence ; Antibodies, Monoclonal/chemistry/immunology/metabolism ; Antibodies, Neutralizing/*chemistry/*immunology/metabolism ; Antibody Affinity ; Antibody Specificity ; Antigens, CD4/metabolism ; Computational Biology ; Computer Simulation ; Crystallography, X-Ray ; Epitopes/immunology ; HIV Antibodies/chemistry/*immunology/metabolism ; HIV Envelope Protein gp120/*chemistry/*immunology/metabolism ; Models, Molecular ; Molecular Mimicry ; Molecular Sequence Data ; Mutagenesis ; Protein Conformation ; *Protein Engineering ; Protein Interaction Domains and Motifs ; Surface Plasmon Resonance

2014-02-07

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

Amino Acid Motifs ; Animals ; Antibodies, Monoclonal/analysis/immunology ; Antibodies, Neutralizing/analysis/immunology ; Antibodies, Viral/analysis/immunology ; Antigens, Viral/chemistry/immunology ; Crystallography, X-Ray ; *Drug Design ; Enzyme-Linked Immunosorbent Assay ; Epitopes/*chemistry/*immunology ; Macaca mulatta/immunology ; Male ; Mice ; Mice, Inbred BALB C ; Models, Molecular ; Neutralization Tests ; Protein Conformation ; *Protein Stability ; Respiratory Syncytial Virus Vaccines/*chemistry/*immunology ; Respiratory Syncytial Viruses/chemistry/immunology

0168-1605

Clonal concept ; Electrotyping ; Plasmid profiling ; Ribotyping ; Salmonella enteritidis

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Process Engineering, Biotechnology, Nutrition Technology

Electronic Resource

1437-1588

Springer Online Journal Archives 1860-2000

Medicine

Darüber hinaus soll das Lebensmittel-Monitoring längerfristig dazu dienen, zeitliche Trends in der Belastung von Lebensmitteln aufzuzeigen und eine ausreichende Datenbasis zu schaffen, um Aufnahmeberechnungen von unerwünschten Stoffen, die der Verbraucher über die Nahrung aufnimmt, durchführen zu können.

Electronic Resource

1434-601X

PACS:14.60.Cd Electrons and positrons – 23.20.Ra Internal pair production – 25.70.Bc Elastic and quasielastic scattering – 25.70.De Coulomb excitation – 25.70.Hi Transfer reaction – 29.30.Aj Charged-particle spectrometers: electric and magnetic

Springer Online Journal Archives 1860-2000

Physics

Abstract. We present the results of a Doppler-shift correction to the measured e+e−–sum-energy spectra obtained from e+e−–coincidence measurements in 238U +206Pb and 238U +181Ta collisions at beam energies close to the Coulomb barrier, using an improved experimental setup at the double-Orange spectrometer of GSI. Internal-Pair-Conversion (IPC) e+e− pairs from discrete nuclear transitions of a moving emitter have been observed following Coulomb excitation of the 1.844 MeV (E1) transition in 206Pb and neutron transfer to the 1.770 MeV (M1) transition in 207Pb. In the collision system 238U +181Ta, IPC transitions were observed from the Ta-like as well as from the U-like nuclei. In all systems the Doppler-shift corrected e+e−–sum-energy spectra show weak lines at the energies expected from the corresponding γ–ray spectra with cross sections being consistent with the measured excitation cross sections of the γ lines and the theoretically predicted IPC coefficients. No other than IPC e+e−–sum-energy lines were found in the measured spectra. The transfer cross sections show a strong dependence on the distance of closest approach (Rmin), thus signaling also a strong dependence on the bombarding energy close to the Coulomb barrier.

Electronic Resource

1434-601X

25.70.Np

Springer Online Journal Archives 1860-2000

Physics

Abstract Subthreshold ¯p andK − and energeticπ − production was studied in Ne + NaF, Cu, Sn and Bi, and in Ni + Ni collisions with incident energies between 1.6 and 2 GeV/u. The measured cross sections indicate a dominant contribution of baryonic resonances. This is also consistent with a generalized scaling behaviour of the cross sections with the energy available in the collision and the energy necessary to produce particles as observed with Ne induced reactions. Deviations from scaling especially pronounced in the Ni-Ni system will be discussed in terms of absorption effects. The flat slope of the excitation function for ¯p production can be related to a reduced production threshold caused by a reduction of the antiproton mass in the dense and heated medium by about 100—150 MeV/c2. A similar in-medium mass reduction is also indicated forK − mesons. An increased ¯p reabsorption probability for the heavier systems is concluded from the comparison of the ¯p yields in Ne + NaF, Ne + Sn and Ni + Ni collisions.

Electronic Resource

1433-0407

Schlüsselwörter Creutzfeldt-Jakob-Krankheit ; Diagnostik ; Diffussionswichtung ; MRT ; Bildgebung ; Übertragbare spongiforme Enzephalopathien ; Key words Creutzfeldt-Jakob disease ; Diagnosis ; Diffusion-weighted image ; MRI ; Brain images ; Transmissible spongiform encephalopathies

Springer Online Journal Archives 1860-2000

Medicine

Summary Today the diagnosis of Creutzfeldt-Jakob disease (CJD) is proven only postmortem or by evidence of neuropathology. During the patient's lifetime EEG recordings or cerebrospinal fluid analysis may support the diagnosis. In most cases, T2-MRI scans show hyperintensities of the basal ganglia. A new imaging technique called diffusion-weighted MRI (DWI) has recently been established. The sensitivity of DWI was evaluated in five patients suspected of CJD. All five cases showed hyperintense signal changes in the basal ganglia on DWI sequences. These findings were more pronounced in DWI than in T2, FLAIR, or PD-weighted images. Thus, DWI seems to be the most sensitive sequence for detecting changes in patients with suspected CJD. Moreover, its short scanning time ensures that fewer artifacts occur, especially in the case of myoclonus.

Zusammenfassung Die sichere Diagnose der Creutzfeldt-Jakob-Krankheit kann nur bioptisch oder autoptisch durch Untersuchung von Hirngewebe gestellt werden. Die klinische Verdachtsdiagnose erhärten können technische und laborchemische Untersuchungen; hierzu gehört neben dem EEG die Surrogatmarkerbestimmung im Liquor. Nachdem sich bei der Mehrzahl der Patienten Veränderungen der Basalganglien gezeigt haben, gehört das MRT zu den bildgebenden Verfahren, die bei Verdacht auf CJD eingesetzt werden können. Inzwischen ist die Diffusionswichtung (DWI) in die neuroradiologische Diagnostik eingeführt worden. DWI-gewichtete MRTs bei 5 CJD-Patienten wurden von uns untersucht. Alle 5 Fälle zeigten im DWI-MRT signalintense Veränderungen der Stammganglien. Diese Veränderungen waren jeweils deutlicher als in der T2, Flair- oder Protonenwichtung. Das DWI-MRT halten wir für sensitiver zum Nachweis kortikaler und basaler Veränderungen bei CJD-Patienten im Vergleich zu Standardsequenzen. Durch die kurze Untersuchungszeit können besonders bei den häufig vorhandenen Myoklonien andere Wichtungen aufgrund von Bewegungsartefakten oftmals nicht in der gewünschten Qualität durchgeführt werden.

Electronic Resource

1432-1750

Springer Online Journal Archives 1860-2000

Medicine

Electronic Resource

1573-7284

Case–control study ; Creutzfeldt–Jakob disease ; Neuroepidemiology ; Stress

Springer Online Journal Archives 1860-2000

Medicine

Abstract The association between Creutzfeldt–Jakob disease (CJD) and stressful life events was examined in a pilot case–control study in Germany. The study sample consisted of 37 CJD cases and 37 controls, both groups were frequency-matched for age and sex. In standardised interviews of close relatives of the cases and the controls, all stressful life events were assessed and subsequently grouped into one of the following three subgroups: psychosocial stress events, medical operations with hospitalisation, and other serious medical examinations. A significantly higher proportion of CJD cases experienced stressful life events during the last six months before disease onset than controls (65% vs. 32%, p = 0.01), yielding an odds ratio (OR) of 3.85 (95% confidence interval (CI): 1.33–11.30). We found the clearest distinction between cases and controls for the subgroup of medical operations where an OR of 6.97 (95% CI: 0.76–329.20) was observed. Further data indicated that stressful events seem to influence not only the onset of CJD but also the progression of the disease. Although based on a rather small study sample, this pilot case–control investigation suggests evidence that stressful life events in the last six months before disease onset may influence CJD occurrence and may modify the course of disease. This ‘stress hypothesis’, which is in line with findings from other epidemiological and experimental studies in CJD, is thus a promising direction for future CJD research as it could enlighten the pathophysiological mechanisms and point towards strategies for the prevention and therapy of CJD.

Electronic Resource

1573-7284

Phage typing ; Phage type 4 (PT4) ; Salmonella enteritidis

Springer Online Journal Archives 1860-2000

Medicine

Abstract In order to monitor the epidemiological situation ofS. enteritidis in Germany, in 1990–91 1138 isolates from more than 180 locations in West Germany were phage typed. 1124 strains (98.8%) from all sources were typeable, belonging to 21 different phage types (PT). PT4 strains were isolated most frequently (70.8%). In addition, PT7, 25, 34 and 8 were of epidemiological relevance with incidences of 7.2 to 4.5%. The comparison of data shows that in Germany, like in other parts of Europe, PT4 predominates. This phage type is, however, infrequent in North America, where PT8 has the highest incidence.

Electronic Resource

1434-601X

14.60.Cd ; 25.70.Cd ; 25.70.Ef

Springer Online Journal Archives 1860-2000

Physics

Abstract We present the results obtained from a series of ρ+ρ−-coincidence measurements in heavy-ion collisions using the double-Orangeβ-spectrometer at GSI. The collision systems U+U, U+Pb, and U+Ta were investigated at bombarding energies close to and slightly above (U+Ta) the Coulomb barrier. For all systems studied, very narrow (FWHM−20 keV) ρ+ρ− lines were observed in the sum-energy spectra, with kinetic energies ranging from ∼555 keV to ∼810 keV, superimposed on a continuous distribution mainly due to uncorrelated ρ+ρ− emission. Particularly in the U+Ta system, a pronounced sum-energy line appears at ∼634 keV, predominantly in deep-inelastic collisions. In some cases (e.g. U+Pb) the line characteristics is consistent with a two-body decay mode of an emitter which moves with the c.m. velocity of the colliding ions. However, other lines, and in particular the 634 keV line (U+Ta), exhibit a rather isotropical opening-angle distribution whereas their energy is unequally shared between positrons and electrons, thus being in clear disagreement with this scenario. In general, the data preclude an emission from the separated (moving) nuclei, and, in the latter cases, provide evidence that the e+e−-pair decay occurs in the vicinity of the Coulomb field of a third heavy (positively charged) partner having only a small transverse velocity (|v|⊥〈0.02c)

Electronic Resource

1434-601X

PACS. 14.60.Cd Electrons and positrons – 23.20.Ra Internal pair production – 25.70.Bc Elastic and quasielastic scattering – 25.70.De Coulomb excitation – 25.70.Hi Transfer reactions – 29.30.Aj Charged particle spectrometers: electric and magnetic

Springer Online Journal Archives 1860-2000

Physics

Abstract: We present new results from measurements and simulations of positron spectra, originating from 238U + 181Ta collisions at beam energies close to the Coulomb barrier. The measurements were performed using an improved experimental setup at the double-Orange spectrometer of GSI. Particular emphasis is put on the signature of positrons from Internal-Pair-Conversion (IPC) processes in the measured e+-energy spectra, following the de-excitation of electromagnetic transitions in the moving Ta-like nucleus. It is shown by Monte Carlo simulations that, for the chosen current sweeping procedure used in the present experiments, positron emission from discrete IPC transitions can lead to rather narrow line structures in the measured energy spectra. The measured positron spectra do not show evidence for line structures within the statistical accuracy achieved, although expected from the intensities of the observed γ-transitions ( E γ∼ 1250-1600 keV) and theoretical conversion coefficients. This is due to the reduced detection efficiency for IPC positrons, caused by the limited spatial and momentum acceptance of the spectrometer. A comparison with previous results, in which lines have been observed, is presented and the implications are discussed.

Electronic Resource

1434-601X

PACS:14.60.Cd Electrons (including positrons) – 23.20.En Angular distributions and correlation measurements – 23.20.Ra Internal pair production – 29.25.Rm Sources of radioactive nuclei – 29.30.Aj Charged-particle spectrometers: electric and magnetic

Springer Online Journal Archives 1860-2000

Physics

Abstract: We present the first energy and angle resolved measurements of e+e−-pairs emitted from heavy nuclei (Z≥ 40) at rest by internal pair conversion (IPC) of transitions with energies of less than 2 MeV as well as recent theoretical results using the DWBA method, which takes full account of relativistic effects, magnetic substates and finite size of the nucleus. The 1.76 MeV E0 transition in 90Zr (90Sr source) and the 1.77 MeV M1 transition in 207Pb (207Bi source) have been investigated experimentally using the essentially improved setup at the double-ORANGE β-spectrometer of GSI. The measurements prove the capability of the setup to cleanly identify the IPC pairs in the presence of five orders of magnitude higher β− and γ background from the same source and to yield essentially background-free sum spectra despite the large background. Using the ability of the ORANGE setup to directly determine the opening angle of the e+e−–pairs (Θe+e−), the angular correlation of the emitted pairs was measured within the range covered experimentally (40°≤Θe+e−≤ 180°). In the 90Zr case the correlation could be deduced for a wide range of energy differences E Δ of the pairs (−530 keV ≤E Δ≤ 530 keV). The 90Zr results are in good agreement with recent theory. The angular correlation deduced for the M1 transition in 207Pb is in strong disagreement with theoretical predictions derived within the Born approximation and shows almost isotropic character. This is again in agreement with the new theoretical results.

Electronic Resource