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| 2. |
- Andersson, Dan, 1966, et al.
(författare)
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Wave-breaking-free pulses in nonlinear-optical fibers
- 1993
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Ingår i: Journal of the Optical Society of America B: Optical Physics. - 1520-8540 .- 0740-3224. ; 10:7, s. 1185-1190
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Tidskriftsartikel (refereegranskat)abstract
- A qualitative as well as quantitative investigation is made of the conditions for avoiding wave breaking during pulse propagation in optical fibers. In particular, it is shown that pulses having a parabolic intensity variation are approximate wave-breaking-free solutions of the nonlinear Schrodinger equation in the high-intensity limit. A simple expression for the compression factor of a fiber-grating compressor based on parabolic pulses is also derived.
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| 3. |
- Baeckström, Dan, 1956, et al.
(författare)
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Purification and characterization of sialyl-Le(a)-carrying mucins of human bile; evidence for the presence of MUC1 and MUC3 apoproteins.
- 1994
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Ingår i: The Journal of biological chemistry. - 0021-9258. ; 269:20, s. 14430-7
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Tidskriftsartikel (refereegranskat)abstract
- Purification of sialyl-Le(a)-carrying mucins from primary human bile by trichloroacetic acid precipitation, delipidation, and gel filtration in guanidinium chloride gave three separable fractions, one of which was further purified by affinity chromatography. These fractions, named SBG1 (for soluble bile glycoprotein), SBG2, and SBG3 had molecular masses of > 1100, 800-950, and 100-250 kDa, respectively, as estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Their mucin characteristics were indicated by a high carbohydrate content, ranging from 74 to 95%. The carbohydrate compositions indicated the presence of very long fucosylated polylactosamine chains. Amino acid analyses showed high abundance of serine and threonine in all three fractions (19-36%), confirming their mucin-like nature. Immunochemical analyses of deglycosylated samples detected the MUC1 mucin apoprotein in SBG2 and the MUC3 protein in SBG1. To our knowledge, this is the first report of a MUC3 mucin being purified. This mucin showed no significant reduction in size upon trypsin treatment or disulfide bond reduction and alkylation. Gel filtration of three samples of secondary bile showed that the size distribution of sialyl-Le(a)-carrying glycoproteins was similar to that found in primary bile, and immunochemical analysis showed that the MUC1 protein was present in all three samples. In one sample an additional fraction was isolated, which was insoluble in 6 M guanidinium chloride, but was solubilized upon reduction and alkylation. mRNAs from gallbladder epithelia were analyzed in Northern blot hybridizations showing that the MUC1 and MUC3 but not the MUC2 mucin apoprotein genes were expressed.
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| 4. |
- Barclay, Susan A, et al.
(författare)
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The shape of the proximal isovelocity surface area varies with regurgitant orifice size and distance from orifice : computer simulation and model experiments with color M-mode technique.
- 1993
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Ingår i: Journal of the American Society of Echocardiography. - 0894-7317 .- 1097-6795. ; 6:4, s. 433-445
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Tidskriftsartikel (refereegranskat)abstract
- The hemispheric proximal isovelocity surface area method for quantification of mitral regurgitant flow (i.e., Qc = 2 pi r2v), where 2 pi r2 is the surface area and v is the velocity at radius r, was investigated as distance from the orifice was increased. Computer simulations and steady flow model experiments were performed for orifices of 4, 6, and 8 mm. Flow rates derived from the centerline velocity and hemispheric assumption were compared with true flow rates. Proximal isovelocity surface area shape varied as distance from each orifice was increased and could only be approximated from the hemispheric equation when a certain distance was exceeded: > 7, > 10, and > 12 mm for the 4, 6, and 8 mm orifices, respectively. Prediction of relative error showed that the best radial zone at which to make measurements was 5 to 9, 6 to 14 and 7 to 17 mm for the 4, 6, and 8 mm orifices, respectively. Although effects of a nonhemispheric shape could be compensated for by use of a correction factor, a radius of 8 to 9 mm can be recommended without the use of a correction factor over all orifices studied if a deviation in calculated as compared with true flow of 15% is considered acceptable. These measurements therefore have implications for the technique in clinical practice.
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| 5. |
- Engström, Tomas, 1950, et al.
(författare)
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Some Findings from Learning of Assembly Work in Sweden
- 1992
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This publication is authored together with senior research competency within work organisation (professor Ulf Karlsson) (who rather inofficially functioned as a tutor for Engström during his PhD-studies, this was necessary since a full professor was lacking for several years at the Departement of Transportation) (in fact we both cooperated for a number of decades) (see some of the other publications registered Chalmer Public Library CPL).
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| 6. |
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| 7. |
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| 8. |
- Karlsson, Magnus, 1967, et al.
(författare)
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A variational approach to optical soliton collisions
- 1994
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Ingår i: Physica Scripta. - : IOP Publishing. - 1402-4896 .- 0031-8949. ; 50:3, s. 265-270
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Tidskriftsartikel (refereegranskat)abstract
- The mathematical analogy between the nonlinear Schrödinger equations describing propagation of temporal soliton pulses in optical fibres, and propagation of spatial soliton beams in planar optical wave guides is discussed. A straightforward variational method, based on trial functions and Rayleigh-Ritz optimization, is demonstrated and applied to incoherent interaction of solitons. We study incoherent soliton interaction in a wavelength-multiplexed optical-fibre communication system, as well as the analogous problem for crossed optical beams in a planar waveguide. The predictions of the variational approach are also shown to be in good agreement with numerical simulation results and with experiments.
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| 9. |
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| 10. |
- Karlsson, Magnus, 1967, et al.
(författare)
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Dynamics of self-focusing and self-phase modulation in a parabolic index optical fiber.
- 1992
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Ingår i: Optics Letters. - 0146-9592 .- 1539-4794. ; 17:1, s. 22-24
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Tidskriftsartikel (refereegranskat)abstract
- The dynamics that result from the combined effects of spatial diffraction, nonlinearity, and a parabolic graded index for wave propagation in optical fibers are presented. An approximate analytical solution of the nonlinear Schrödinger equation in a graded-index fiber is obtained by using a variational approach. Particular emphasis is put on the variation of both the pulse width and the longitudinal phase delay with the distance of propagation along the fiber.
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