| 11. |
- Cooper, M. D., et al.
(författare)
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Construction and performance of MEGA's low-mass, high-rate cylindrical MWPCs
- 1998
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier. - 0168-9002 .- 1872-9576. ; 417:1, s. 24-49
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Tidskriftsartikel (refereegranskat)abstract
- A design for extremely low mass, high-resolution multiwire proportional chambers (MWPC) was achieved by the MEGA collaboration in its experiment to search for the lepton family number violating decay μ → eγ. To extend the present branching ratio limit by over an order of magnitude, these MWPCs were operated in high particle fluxes. They showed minimal effects of aging, and evidenced spatial and energy resolutions for the orbiting positrons from muon decay which were consistent with our design parameters. The unique features of these chambers, their assembly into the MEGA positron spectrometer, and their performance during the experiment are described in this paper.
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| 12. |
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| 13. |
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| 14. |
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| 15. |
- Hjerten, S, et al.
(författare)
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Gels mimicking antibodies in their selective recognition of proteins
- 1997
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Ingår i: CHROMATOGRAPHIA. - : VIEWEG. - 0009-5893. ; 44:5-6, s. 227-234
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- In a previous paper we presented preliminary experiments aimed at the preparation of gel particles with the property to recognize selectively some particular protein (hemoglobin, cytochrome C, transferrin) [1]. Using the same method we show in this articl
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| 16. |
- Hong, J., et al.
(författare)
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Plasma chemistries for high density plasma etching of SiC
- 1999
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Ingår i: Journal of Electronic Materials. - Charlottesville, VA, USA. - 0361-5235 .- 1543-186X. ; 28:3, s. 196-201
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Tidskriftsartikel (refereegranskat)abstract
- A variety of different plasma chemistries, including SF6, Cl2, ICI, and IBr, have been examined for dry etching of 6H-SiC in high ion density plasma tools (inductively coupled plasma and electron cyclotron resonance). Rates up to 4500 angstroms·min-1 were obtained for SF6 plasmas, while much lower rates (≀800 angstroms·min-1) were achieved with Cl2, ICI, and IBr. The F2-based chemistries have poor selectivity for SiC over photoresist masks (typically 0.4-0.5), but Ni masks are more robust, and allow etch depths ≥10 Όm in the SiC. A micromachining process (sequential etch/deposition steps) designed for Si produces relatively low etch rates (<2,000 angstroms·min-1) for SiC.
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| 17. |
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| 18. |
- Huang, QW, et al.
(författare)
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Effects of inhaled nitric oxide and high-frequency ventilation in rabbits with meconium aspiration
- 1999
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Ingår i: Biology of the neonate. - : S. Karger AG. - 0006-3126. ; 76:6, s. 374-382
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Tidskriftsartikel (refereegranskat)abstract
- Aim: To evaluate effects of inhaled nitric oxide (iNO) in experimental meconium aspiration treated with high-frequency (HFV) or conventional mechanical ventilation (CMV). Ventilated adult rabbits had meconium instilled intratracheally resulting in respiratory failure as evidenced by more than 50% reduction of dynamic lung compliance (Cdyn) and increase in mean oxygenation index (OI) from 1 to 16. The animals were then allocated to 2 groups treated without (control) or with iNO at 20 ppm (NO). In each group the animals were initially ventilated with CMV or HFV mode for 3 h and then in a crossover fashion with HFV or CMV for another 3 h (CMV→HFV, HFV→CMV), respectively. In the first 3 h of treatment, the animals subjected to HFV-CMV in the control, and those with both HFV-CMV and CMV-HFV in the NO group had significantly reduced OI. In the subsequent 3 h, the animals in the control group with CMV-HFV did not improve in OI and those with HFV-CMV had deteriorated. In the NO group with both CMV-HFV and HFV-CMV moderate improvement of OI was observed. Platelet aggregation capability and counts were significantly decreased and bleeding time prolonged in animals receiving iNO treatment. These results suggest that both HFV alone and a combined treatment of iNO with either CMV or HFV are more effective in improving blood oxygenation than that of CMV in this animal model. The influence of iNO on platelet aggregation should be considered.
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| 19. |
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| 20. |
- Kolm, Rüdiger H., et al.
(författare)
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Isothiocyanates as substrates for human glutathione transferases : structure-activity studies
- 1995
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Ingår i: Biochemical Journal. - 0264-6021 .- 1470-8728. ; 311, s. 453-459
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Tidskriftsartikel (refereegranskat)abstract
- The catalytic properties of four human glutathione transferases (GSTs), A1-1, M1-1, M4-4 and P1-1, were examined with 14 isothiocyanate (R-NCS) substrates. The compounds include aliphatic and aromatic homologues, some of which are natural constituents of human food, namely sulphoraphane [1-isothiocyanato-4-(methylsulphinyl)butane], erucin [1-isothiocyanato-4-(methylthio)butane], erysolin [1-isothiocyanato-4-(methylsulphonyl)butane], benzyl-NCS, phenethyl-NCS and allyl-NCS. All isothiocyanates investigated were substrates for the four GSTs. The enzymes promote addition of the thiol group of GSH to the electrophilic central carbon of the isothiocyanate group to form dithiocarbamates [R-NH-C(=S)-SG] which have high UV absorption at 274 nm. Molar absorption coefficients and non-enzymic rate constants as well as standardized enzyme assay conditions for all compounds were established. Of the four isoenzymes investigated, GSTs M1-1 and P1-1 were generally the most efficient catalysts, whereas GST M4-4 was the least efficient. Isothiocyanates are among the GST substrates that are most rapidly conjugated. On the basis of rate-enhancement data and binding energies, the isothiocyanates were compared with 4-hydroxyalkenals, another class of natural GST substrates previously subjected to systematic kinetic analysis. The incremental transition-state stabilization attributable to an increased number of methylene groups in homologous alkyl isothiocyanates is similar to that previously noted for homologous 4-hydroxyalkenals.
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