Long-pulse operation at constant output power and single-frequency mode of a high-power electrostatic free-electron maser with depressed collector

The Fusion Free-Electron Maser (FFF) is the prototype of a high-power, tunable source of mm-wave radiation, for use on fusion plasma devices. In previous experiments a net output power of 730 kW at 206 GHz was generated in short pulses. The present experiment has been equipped with a system to recover the charge and energy of the spent electron beam. We present experimental results which show output of mm-wave radiation at constant power level during the full pulse length, as well as single-frequency operation; even though the cavity is highly overmoded; the latter is reached by effective suppression of spurious modes by the feedback system.     

Search for disoriented chiral condensate in 158<Emphasis Type="Italic">A</Emphasis> GeV Pb+Pb collisions in WA98 experiment

The current status of the search for localized domains of disoriented chiral condensates (DCC) in Pb+Pb collisions at 158A GeV/c are presented. A new method based on the discrete wavelet transformation (DWT) technique along with an analysis of correlation between charged and neutral particles has been used for the search of localized DCC domains. We show that both the methods indicate the presence of non-statistical fluctuations in data.     

A laser extraction/combustion technique for in situ delta(13)C analysis of organic and inorganic materials

A CO(2) laser extraction system is described for in situ delta(13)C analysis of organic and inorganic materials. Carbonaceous compounds volatilized by the laser are quantitatively converted to CO(2) gas by a combustion furnace mounted after the sample chamber. Gases produced by the laser and combustion processes are swept by helium carrier gas and separated by a packed gas chromatography column prior to their introduction to an isotope ratio monitoring mass spectrometer. A sample of lentil bean was analyzed at a spatial resolution of 200 μm and yielded delta(13)C values with precision of +/- 0.3 per thousand. The accuracy of delta(13)C measurements was better than +/- 0.5 per thousand from NBS 22 (mineral oil), USGS 24 (graphite), and IAEA CO-1 (calcium carbonate). Copyright 1999 John Wiley & Sons, Ltd.     

Kinetic Resolution of Azomethine Imines by Brønsted Acid Catalyzed Enantioselective Reduction

Azomethine imines are valuable substrates in asymmetric catalysis, and can be precursors to β‐amino carbonyl compounds and complex hydrazines. However, their utility is limited because complex and enantioenriched azomethine imines are often unavailable. Reported herein is a kinetic resolution of N,N′‐cyclic azomethine imines by enantioselective reduction (s=13–43). This resolution was accomplished using a Brønsted acid catalyst, and represents the first example of the asymmetric reduction of azomethine imines. The pyrazolidinone product (up to 86 % ee) and the recovered azomethine imine (up to 99 % ee) can both be used to access the opposite enantiomers of valuable products.     

Localized in vivo H spectroscopy of human skeletal muscle: Normal and pathologic findings

To obtain high signal to noise ratio in small volume elements (8 cm³), in vivo ¹H NMR spectroscopy of normal and diseased human skeletal muscle was performed using a double spin-echo localization method on a 1.5-T whole body system. High resolved spectra of normal calf muscle show the well known resonances of lipids (methyl, methylene, olefinic, and other fatty acid resonances), creatine/phosphocreatine, choline/carnitine, taurine, and histidine with good intraindividual reproducibility. Pronounced intraindividual differences in the lipid range were found between different upper thigh muscle groups. On pathologic conditions like myopathia, myositis or irradiation damage the spectral lipid content was increased. Three months after local irradiation of the medial vastus muscle (50 Gy), the localized ¹H NMR spectrum showed a complete loss of the choline and creatine signals. In a case of M. Behçet with muscular involvement the relative reduction of the choline signal may provide an insight in the pathobiochemistry. The results of our investigations in nine healthy volunteers and three patients are presented in detail including relaxation times of the metabolites.     

Existence and bifurcation theorems for nonlinear elliptic eigenvalue problems on unbounded domains

We consider nonlinear elliptic eigenvalue problems on unbounded domains G?$\text{R}$ⁿ. Using an extended Ljusternik-Schnirelman theory we prove the existence of infinitely many eigenfunctions on every sphere in L²(G). Moreover, we establish that the infimum λ1 of the spectrum of the linearized problem L is always a bifurcation point. In addition, there is an infinity of branches emanating at λ1 from the trivial line of solutions if λ1 belongs to the essential spectrum of L.     

Coherent production ofρ − mesons in charged current antineutrino-neon interactions in BEBC

Coherent production ofρ ^? mesons in charged current antineutrino interactions on neon nuclei is studied in the BEBC bubble chamber exposed to the CERN SPS wide band beam. The cross section is measured to be (95±25)·10^?40 cm² per neon nucleus, averaged over the beam energy spectrum. The distributions of kinematical variables and the absolute value of the cross section are in agreement with theoretical predictions based on the CVC hypothesis and the vector meson dominance model.     

Evidence for higher twist effects in fast π− production by antineutrinos in neon

Evidence for a significant higher twist contribution to highz π^? production in antineutrino scattering is presented. In events withW>3 GeV andQ ²>1 GeV² in our data, it accounts for (51 ±8)% of all π^? withz above 0.5. It is consistent with thez?Q ² correlations of Berger's higher twist prediction. The data are inconclusive concerning the predictedy?z correlation andp _T dependence. Thez ?Q ² correlation is not adequately described by the Lund Monte-Carlo.     

Characterization of glycosylation sites for a recombinant IgG1 monoclonal antibody and a CTLA4-Ig fusion protein by liquid chromatography-mass spectrometry peptide mapping

Liquid chromatography mass spectrometry (LC-MS) peptide mapping can be a versatile technique for characterizing protein glycosylation sites without the need to remove the attached glycans as in conventional oligosaccharide mapping methods. In this way, both N-linked and O-linked sites of glycosylation can each be directly identified, characterized, and quantified by LC-MS as intact glycopeptides in a single experiment. LC-MS peptide mapping of the individual glycosylation sites avoids many of the limitations of preparing and analyzing an entire pool of released N-linked oligosaccharides from all sites mixed together. In this study, LC interfaced to a linear ion trap mass spectrometer (ESI-LIT-MS) were used to characterize the glycosylation of a recombinant IgG1 monoclonal antibody and a CTLA4-Ig fusion protein with multiple sites of N-and O-glycosylation. Samples were reduced, S-carboxyamidomethylated, and cleaved with either trypsin or endoproteinase Asp-N. Enhanced detection for minor IgG1 glycoforms (～0.1 to 1.0 mol% level) was obtained by LC-MS of the longer 32-residue Asp-N glycopeptide (4+ protonated ion) compared to the 9-residue tryptic glycopeptide (2+ ion). LC-MS peptide mapping was run according to a general procedure: (1) Locate N-linked and/or O-linked sites of glycosylation by selected-ion-monitoring of carbohydrate oxonium fragment ions generated by ESI in-source collision-induced dissociation (CID), i.e. 204, 366, and 292 Da marker ions for HexNAc, HexNAc-Hex, and NeuAc, respectively; (2) Characterize oligosaccharides at each site via MS and MSMS. Use selected ion currents (SIC) to estimate relative amounts of each glycoform; and (3) Measure the percentage of site-occupancy by searching for any corresponding nonglycosylated peptide.     

Transverse energy production in the target fragmentation region in16O-nucleus reactions at 60 and 200A GeV

Charged pion yields and transverse energies of baryons are measured for the reaction¹⁶O+Cu, Ag, Au at 60 and 200A GeV bombarding energy in the target fragmentation region employing the Plastic Ball detector. Only little dependence of the measured quantities on the bombarding energy is found. The data are compared with the multi-chain fragmentation model of Ranft. As a result it turns out that a leading order formation zone cascade is not sufficient to explain the baryon yield and the transverse energies of baryons in the target fragmentation region.