X-ray spectroscopy of warm and hot electron components in the CAPRICE source plasma at EIS testbench at GSI.

An experimental campaign aiming to detect X radiation emitted by the plasma of the CAPRICE source - operating at GSI, Darmstadt - has been carried out. Two different detectors (a SDD - Silicon Drift Detector and a HpGe - hyper-pure Germanium detector) have been used to characterize the warm (2-30 keV) and hot (30-500 keV) electrons in the plasma, collecting the emission intensity and the energy spectra for different pumping wave frequencies and then correlating them with the CSD of the extracted beam measured by means of a bending magnet. A plasma emissivity model has been used to extract the plasma density along the cone of sight of the SDD and HpGe detectors, which have been placed beyond specific collimators developed on purpose. Results show that the tuning of the pumping frequency considerably modifies the plasma density especially in the warm electron population domain, which is the component responsible for ionization processes: a strong variation of the plasma density near axis region has been detected. Potential correlations with the charge state distribution in the plasma are explored.

A status report of the multipurpose superconducting electron cyclotron resonance ion source.

Intense heavy ion beam production with electron cyclotron resonance (ECR) ion sources is a common requirement for many of the accelerators under construction in Europe and elsewhere. An average increase of about one order of magnitude per decade in the performance of ECR ion sources was obtained up to now since the time of pioneering experiment of R. Geller at CEA, Grenoble, and this trend is not deemed to get the saturation at least in the next decade, according to the increased availability of powerful magnets and microwave generators. Electron density above 10(13) cm(-3) and very high current of multiply charged ions are expected with the use of 28 GHz microwave heating and of an adequate plasma trap, with a B-minimum shape, according to the high B mode concept [S. Gammino and G. Ciavola, Plasma Sources Sci. Technol. 5, 19 (1996)]. The MS-ECRIS ion source has been designed following this concept and its construction is underway at GSI, Darmstadt. The project is the result of the cooperation of nine European institutions with the partial funding of EU through the sixth Framework Programme. The contribution of different institutions has permitted to build in 2006-2007 each component at high level of expertise. The description of the major components will be given in the following with a view on the planning of the assembly and commissioning phase to be carried out in fall 2007. An outline of the experiments to be done with the MS-ECRIS source in the next two years will be presented.

Differential effects of (D)- and (L)-homocysteic acid on the membrane potential of cat caudate neurons in situ.

The enantiomers of homocysteic acid have been applied by microiontophoresis to neurons of the cat caudate nucleus in situ. The (L)-enantiomer elicited a bursty firing pattern similar to the one caused by N-methyl-D-aspartate, but differing from the N-methyl-D-aspartate pattern inasmuch as (L)-homocysteate induced depolarization shifts were shorter and had a smaller amplitude. (L)-Homocysteate induced excitations could be strongly inhibited by the selective N-methyl-D-aspartate antagonist 2-amino-7-phosphonoheptanoic acid but they were less sensitive to this antagonist than N-methyl-D-aspartate itself. (D)-Homocysteate elicited a more regular firing pattern similar to the one caused by non-N-methyl-D-aspartate excitatory amino acids such as quisqualate. These excitations were only rarely inhibited by 2-amino-7-phosphonoheptanoic acid. Our results suggest that (L)-homocysteate, a transmitter candidate at central mammalian synapses, is a mixed excitatory amino acid agonist with a strong preference for N-methyl-D-aspartate receptors in the cat caudate nucleus, while (D)-homocysteate has a predominant action at non-N-methyl-D-aspartate excitatory amino acid receptors.

[Significance of reciprocal ST-segment depression in the acute stage of transmural myocardial infarct]. / Zur Bedeutung reziproker ST-Senkungen im Akutstadium des transmuralen Myokardinfarktes.

19 patients with transitory ST-segment depression in the wall opposite the infarcted territory during acute transmural myocardial infarction (AMI) were studied. We investigated the reproducibility of this reciprocal ST depression induced by stress testing and correlated the ECG changes with coronary angiographic evaluation of arteries supplying the remote area. We tried to derive criteria for detection of simple mirror image. 3 different groups were defined according to ECG evolution: Group 1 consisted of 7 anterior and 3 inferior AMI where reciprocal ECG changes disappeared appeared within 24 to 48 hours independently of the ECG changes in the infarcted area. These ST depressions were reproduced by stress testing one to two months later, and correlated angiographically with an anatomic lesion. 7 out of 10 patients later had bypass graft surgery. Group 2 consisted of 7 patients in whom posterior wall extension of an inferior AMI made the diagnosis of anterior ischemia impossible. In another two patients (one anterior and one inferior AMI) reciprocal ST depression and infarcted area ECG changes showed a simultaneous evolution. The reciprocal ST depression could not be reproduced during stress testing and did not correlate with any angiographic lesion. It is concluded that reciprocal ST depression during the acute phase of transmural anterior or purely inferior myocardial infarction is correlated with multivessel coronary disease if their regression is not strictly simultaneous to the infarction-related ECG changes. Further investigations are indicated in these patients.

Brain postsynaptic densities: the relationship to glial and neuronal filaments.

Preparations of isolated brain postsynaptic densities (PSDs) contain a characteristic set of proteins among which the most prominent has a molecular weight of approximately 50,000. Following the suggestion that this major PSD protein might be related to a similarly sized component of neurofilaments (F. Blomberg et al., 1977, J. Cell Biol., 74:214-225), we searched for evidence of neurofilament proteins among the PSD polypeptides. This was done with a novel technique for detecting protein antigens in SDS-polyacrylamide gels (immunoblotting) and an antiserum that was selective for neurofilaments in immunohistochemical tests. As a control, an antiserum against glial filament protein (GFAP) was used because antisera against GFAP stain only glial cells in immunohistochemical tests. They would, therefore, not be expected to react with PSDs that occur only in neurons. The results of these experiments suggested that PSDs contain both neuronal and also glial filament proteins at higher concentrations than either synaptic plasma membranes, myelin, or myelinated axons. However, immunoperoxidase staining of histological sections with the same two antisera gave contradictory results, indicating that PSDs in intact brain tissue contain neither neuronal or glial filament proteins. This suggested that the intermediate filament proteins present in isolated PSD preparations were contaminants. To test this possibility, the proteins of isolated brain intermediate filaments were labeled with 125I and added to brain tissue at the start of a subcellular fractionation schedule. The results of this experiment confirmed that both neuronal and glial filament proteins stick selectively to PSDs during the isolation procedure. The stickiness of PSDs for brain cytoplasmic proteins indicates that biochemical analysis of subcellular fractions is insufficient to establish a given protein as a synaptic junctional component. An immunohistochemical localization of PSDs in intact tissue, which has now been achieved for tubulin, phosphoprotein I, and calmodulin, appears to be an essential accessory item of evidence. Our findings also corroborate recent evidence which suggests that isolated preparations of brain intermediate filaments contain both neuronal and glial filaments.

[Risk factors and psycho-social factors in myocardial infarct of the young man]. / Facteurs de risque et facteurs psycho-sociaux dans l'infarctus myocardique de l'homme jeune.

Psychosocial and standard risk factors were assessed in 21 young males aged 32--45 admitted for acute myocardial infarction. All patients underwent extensive clinical, dietary and psychosocial investigation by a team of cardiologists, psychiatrists, dieticians, social workers and physiotherapists both during hospitalization and later at home. Most standard risk factors were found infrequently and the estimated risk of coronary disease would have been low. Heavy smokers (1--4 packs of cigarettes per day) totalled 20/21 patients. In every case the patients, before myocardial infarction, had sustained severe long-term stress in their professional, social and/or familial environments. With rigid and obsessive personality patterns, they appeared to be the prisoners of their problem situations and totally unable to relax. Severe psychosocial stress and heavy smoking appear to be almost constant findings in young males admitted with acute myocardial infarction.

[Early mobilization in the acute stage of myocardial infarction long term results]. / La mobilisation précoce au stade aigu de l'infarctus du myocarde: résultats à long terme

A report is presented on the continuation of a controlled study on early mobilization after acute myocardial infarction performed at the Cantonal Hospital of Geneva. Detailed follow-up studies were made in the patients from the original study 4 years on average after the myocardial infarction. It is well known that early mobilization offers many advantages over prolonged bed rest. The present study demonstrates that early mobilization after acute myocardial infarction involves no longterm risks.