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152. Species-specific isotope-ratio measurements of volatile tin and antimony compounds using capillary GC-ICP-time-of-flight MS

Author

Haas, K., Feldmann, J., Wennrich, Rainer, Stärk, Hans-Joachim, Haas, K., Feldmann, J., Wennrich, Rainer, and Stärk, Hans-Joachim

Abstract

The analytical performance of an axial inductively-coupled-plasma time-of-flight mass spectrometer (ICP–TOFMS) as a detector for fast transient chromatographic signals resulting from the coupling to capillary gas chromatography (CGC) was investigated. A cryotrapping GC–ICP–TOFMS method for the determination of volatile metal(loid) compounds (VOMs) in gases was used and the suitability of the TOF mass analyzer for multi-elemental speciation analysis and multi-isotope ratio determinations was studied in terms of accuracy and precision. Isotope ratios 118Sn/120Sn and 121Sb/123Sb have been determined in in-house gas standard atmospheres in Tedlar bags at two different levels (100 pg and 1 ng) for different elemental species (SnH4, MeSnH3, Me2SnH2, Me3SnH, BuSnH3, SbH3, and MeSbH2). A limitation arising from counting statistics in both detection modes could be shown. A solution containing rhodium (10 ng mL–1) and cadmium (40 ng mL–1) was introduced simultaneously to the GC outlet. Rhodium acts as a continuous internal standard and Cd is used for mass-bias correction (by measuring the 111Cd/113Cd ratio). The detection system in both pulse counting and analog mode was examined. The best attainable precision was established for Me2SnH2 (analog mode, 12 replicates, 1 ng, RSD 0.34%, accuracy 0.31%) whereas most other species ranged between 0.4 and 0.5% RSD if higher concentrations were used. The limitations of the pulse counting system are clearly seen, with peak heights of more than 2000 counts reaching saturation (for an integration time of 100 ms), which reduces the accuracy of isotope ratio determinations. A dozen VOM could be detected in an aged landfill gas sample; several unidentified Sn compounds were present. Although their isotope ratios are within the confidence value of the standards, it is not yet clear if the acquired precision is good enough to identify isotopic fractionation of metal(loid)s through biovolatilization processes. With the precision achieved, the

Published
2001

169. Measurement of γp→K+Λ and γp→K+Σ0 at photon energies up to 2 GeV

Author

Tran, M.Q., primary, Barth, J., additional, Bennhold, C., additional, Bockhorst, M., additional, Braun, W., additional, Budzanowski, A., additional, Burbach, G., additional, Burgwinkel, R., additional, Ernst, J., additional, Glander, K.H., additional, Goers, S., additional, Guse, B., additional, Haas, K.-M., additional, Hannappel, J., additional, Heinloth, K., additional, Honscheid, K., additional, Jahnen, T., additional, Jöpen, N., additional, Jüngst, H., additional, Kalinowsky, H., additional, Kirch, U., additional, Klein, F.J., additional, Klein, F., additional, Klempt, E., additional, Kostrewa, D., additional, Kozela, A., additional, Lawall, R., additional, Lindemann, L., additional, Link, J., additional, Manns, J., additional, Mart, T., additional, Menze, D., additional, Merkel, H., additional, Merkel, R., additional, Neuerburg, W., additional, Paganetti, M., additional, Paul, E., additional, Plötzke, R., additional, Schenk, U., additional, Scholmann, J., additional, Schulday, I., additional, Schumacher, M., additional, Schütz, P., additional, Schwille, W.J., additional, Smend, F., additional, Smyrski, J., additional, Speth, W., additional, Tran, H.N., additional, van Pee, H., additional, Vogl, W., additional, Wedemeyer, R., additional, Wehnes, F., additional, Wiegers, B., additional, Wieland, F.W., additional, Wißkirchen, J., additional, and Wolf, A., additional

Published
1998
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176. Hypercapnic and hypoxic ventilatory responses

Author

Abraham, K., primary, Adamany, D., additional, Austin, K., additional, Benz, S., additional, DalPonte, D., additional, Davis, R., additional, Haas, K., additional, Hendricks, M., additional, and Westhead, E., additional

Published
1996
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180. Measurement of γp→K+Λ and γp→K+Σ0 at photon energies up to 2.1 GeV

Author

Bockhorst, M., primary, Burbach, G., additional, Burgwinkel, R., additional, Empt, J., additional, Guse, B., additional, Haas, K.-M., additional, Hannappel, J., additional, Heinloth, K., additional, Hey, T., additional, Hoffmann-Rothe, P., additional, Honsheid, K., additional, Jahnen, T., additional, Jakob, H. P., additional, Jöpen, N., additional, Jüngst, H., additional, Kirch, U., additional, Klein, F.-J., additional, Kostrewa, D., additional, Lindemann, L., additional, Link, J., additional, Manns, J., additional, Menze, D., additional, Merkel, H., additional, Merkel, R., additional, Neuerburg, W., additional, Paul, E., additional, Plötzke, R., additional, Schenk, U., additional, Schmidt, S., additional, Scholmann, J., additional, Schütz, P., additional, Schultz-Coulon, H.-C., additional, Schweitzer, M., additional, Schwille, W. J., additional, Tran, M.-Q., additional, Umlauf, G., additional, Vogl, W., additional, Wedemeyer, R., additional, Wehnes, F., additional, Wiβkirchen, J., additional, and Wolf, A., additional

Published
1995
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182. Design and construction of the SAPHIR detector

Author

Schwille, W.J., primary, Bockhorst, M., additional, Burbach, G., additional, Burgwinkel, R., additional, Empt, J., additional, Guse, B., additional, Haas, K.-M., additional, Hannappel, J., additional, Heinloth, K., additional, Hey, T., additional, Honscheid, K., additional, Jahnen, T., additional, Jakob, H.P., additional, Jöpen, N., additional, Jüngst, H., additional, Kirch, U., additional, Klein, F.-J., additional, Kostrewa, D., additional, Lindemann, L., additional, Link, J., additional, Manns, J., additional, Menze, D., additional, Merkel, H., additional, Merkel, R., additional, Neuerburg, W., additional, Paul, E., additional, Plötzke, R., additional, Schenk, U., additional, Schmidt, S., additional, Scholmann, J., additional, Schütz, P., additional, Schultz-Coulon, H.-C., additional, Schweitzer, M., additional, Tran, M.-Q., additional, Vogl, W., additional, Wedemeyer, R., additional, Wehnes, F., additional, Wißkirchen, J., additional, and Wolf, A., additional

Published
1994
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192. Targeted electroporation in Xenopus tadpolesin vivo – from single cells to the entire brain.

Author

Haas, K., Jensen, K., Sin, W. C., Foa, L., and Cline, H. T.

Subjects
XENOPUS, ELECTROPORATION, GENE transfection, NEUROPLASTICITY
Abstract

Electroporation is becoming more popular as a technique for transfecting neurons within intact tissues. One of the advantages of electroporation over other transfection techniques is the ability to precisely target an area for transfection. Here we highlight this advantage by describing methods to restrict transfection to either a single cell, clusters of cells, or to include large portions of the brain of the intact Xenopus tadpole. Electroporation is also an effective means of gene delivery in the retina. We have developed these techniques to examine the effects of regulated gene expression on various neuronal properties, including structural plasticity and synaptic transmission. Restriction of transfection to individual cells aids in imaging of neuronal morphology, while bulk cell transfection allows examination of the affects of gene expression on populations of cells by biochemical assays, imaging, and electrophysiological recording. [ABSTRACT FROM AUTHOR]

Published
2002
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194. Measurement of γ p→ K Λ and γ p→ K Σ at photon energies up to 1.47 GeV.

Author

Bockhorst, M., Burbach, G., Burgwinkel, R., Empt, J., Guse, B., Haas, K., Hannappel, J., Heinloth, K., Hey, T., Hoffmann-Rothe, P., Honscheid, K., Jahnen, T., Jakob, H., Jöpen, N., Jüngst, H., Kirch, U., Klein, F., Kostrewa, D., Lindemann, L., and Link, J.

Abstract

The reactions γ p→ K Λ and γ p→ K Σ have been measured with the multiparticle detector system SAPHIR at ELSA in Bonn. Besides the differential cross sections the Λ polarization and, for the first time, the Σ polarization have been determined in a photon induced reaction. All data are presented as functions of the photon energy (from threshold up to 1.47 GeV) and of the kaon production angle (0°-180°). The polarization of both Λ and Σ is substantial at all energies and varies strongly with the production angle. [ABSTRACT FROM AUTHOR]

Published
1994
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195. Amino acid utilization and isotope discrimination of amino nitrogen in nitrogen metabolism of rat liver in vivo.

Author

Sick, H., Roos, N., Saggau, E., Haas, K., Meyn, V., Walch, B., and Trugo, N.

Abstract

Copyright of Zeitschrift für Ernäehrungswissenschaft is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Published
1997
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200. Use of the Mannan Receptor to Selectively Target Vaccine Antigens for Processing and Antigen Presentation through the MHC Class I and Class II Pathways

Author

DAVIS, W. C., KONZEK, R. L., HAAS, K., ESTES, D. M., HAMILTON, M. J., CALL, D. R., APOSTOLOPOULOS, V., and MCKENZIE, I.F. C.

Abstract

Extensive studies have shown that synthetic and recombinant vaccines developed against hemoparasites have not been as effective as whole parasites or crude membrane fractions in eliciting protective immunity. A possible reason is that synthetic vaccines are not being presented in a form that induces the appropriate immune response. We have developed a bovine model system to evaluate the ability of adjuvant compounds to induce an immune response to peptide antigens dominated by a cytokine profile with a Type 1 (cell-mediated) or Type 2 (humoral) bias. In the initial testing of this system, we found that mRNA expression of certain cytokines (interleukin [IL]-1?, IL-6, IL-12, IL-15, GM-CSF, iNOS, and tumor necrosis factor [TNF]-?) is enhanced when monocyte-derived macrophages are stimulated with peptide antigen conjugated with mannan under oxidizing conditions compared to peptide conjugated with reduced mannan. The data suggest this model will be useful in identifying adjuvant systems that selectively modulate the cytokine profile of antigen presenting cells at the time of antigen presentation and the consequent downstream maturation of naive T cells to effector cells with Type 1 or Type 2 cytokine bias.

Published
2002
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