| 1. |
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| 2. |
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| 3. |
- Edelson, R. A., et al.
(författare)
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Multiwavelength observations of short-timescale variability in NGC 4151. IV. Analysis of multiwavelength continuum variability
- 1996
-
Ingår i: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 470:1, s. 364-377377
-
Tidskriftsartikel (refereegranskat)abstract
- For pt.III see ibid., vol.470, no.1, p.349-63 (1996). Combines data from the three preceding papers in order to analyze the multi wave-band variability and spectral energy distribution of the Seyfert 1 galaxy NGC 4151 during the 1993 December monitoring campaign. The source, which was near its peak historical brightness, showed strong, correlated variability at X-ray, ultraviolet, and optical wavelengths. The strongest variations were seen in medium-energy (~1.5 keV) X-rays, with a normalized variability amplitude (NVA) of 24%. Weaker (NVA=6%) variations (uncorrelated with those at lower energies) were seen at soft gamma-ray energies of ~100 keV. No significant variability was seen in softer (0.1-1 keV) X-ray bands. In the ultraviolet/optical regime, the NVA decreased from 9% to 1% as the wavelength increased from 1275 to 6900 Aring. These data do not probe extreme ultraviolet (1200 Aring to 0.1 keV) or hard X-ray (250 keV) variability. The phase differences between variations in different bands were consistent with zero lag, with upper limits of lsim0.15 day between 1275 Aring and the other ultraviolet bands, lsim0.3 day between 1275 Aring and 1.5 keV, and lsim1 day between 1275 and 5125 Aring. These tight limits represent more than an order of magnitude improvement over those determined in previous multi-wave-band AGN monitoring campaigns. The ultraviolet fluctuation power spectra showed no evidence for periodicity, but were instead well fitted with a very steep, red power law (ales-2.5)
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| 4. |
- Crenshaw, D. M., et al.
(författare)
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Multiwavelength observations of short-timescale variability in NGC 4151. I. Ultraviolet observations
- 1996
-
Ingår i: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 470:1, s. 322-335335
-
Tidskriftsartikel (refereegranskat)abstract
- Presents the results of an intensive ultraviolet monitoring campaign on the Seyfert 1 galaxy NGC 4151, as part of an effort to study its short-timescale variability over a broad range in wavelength. The nucleus of NGC 4151 was observed continuously with the International Ultraviolet Explorer for 9.3 days, yielding a pair of LWP and SWP spectra every ~70 minutes, and during 4 hr periods for 4 days prior to and 5 days after the continuous-monitoring period. The sampling frequency of the observations is an order of magnitude higher than that of any previous UV monitoring campaign on a Seyfert galaxy. The continuum fluxes in bands from 1275 to 2688 Aring went through four significant and well-defined ldquoeventsrdquo of duration 2-3 days during the continuous-monitoring period. The authors find that the amplitudes of the continuum variations decrease with increasing wavelength, which extends a general trend for this and other Seyfert galaxies to smaller timescales (i.e., a few days). The continuum variations in all the UV bands are simultaneous to within an accuracy of ~0.15 days, providing a strict constraint on continuum models. The emission-line light curves show only one major event during the continuous monitoring (a slow rise followed by a shallow dip) and do not correlate well with continuum light curves over the short duration of the campaign, because the timescale for continuum variations is apparently smaller than the response times of the emission lines
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| 5. |
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| 6. |
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| 7. |
- Dujon, B, et al.
(författare)
-
The nucleotide sequence of Saccharomyces cerevisiae chromosome XV
- 1997
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 387:6632, s. 98-102
-
Tidskriftsartikel (refereegranskat)abstract
- Chromosome XV was one of the last two chromosomes of Saccharomyces cerevisiae to be discovered(1). It is the third-largest yeast chromosome after chromosomes XII and IV, and is very similar in size to chromosome VII. It alone represents 9% of the yeast genome (8% if ribosomal DNA is included). When systematic sequencing of chromosome XV was started, 93 genes or markers were identified, and most of them were mapped(2). However, very little else was known about chromosome XV which, in contrast to shorter chromosomes, had not been the object of comprehensive genetic or molecular analysis. It was therefore decided to start sequencing chromosome XV only in the third phase of the European Yeast Genome Sequencing Programme, after experience was gained on chromosomes III, XI and II (refs 3-5). The sequence of chromosome XV has been determined from a set of partly overlapping cosmid clones derived from a unique yeast strain, and physically mapped at 3.3-kilobase resolution before sequencing. As well as numerous new open reading frames (ORFs) and genes encoding tRNA or small RNA molecules, the sequence of 1,091,283 base pairs confirms the high proportion of orphan genes and reveals a number of ancestral and successive duplications with other yeast chromosomes.
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| 8. |
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| 9. |
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| 10. |
- Chulkov, L. V., et al.
(författare)
-
Large spin alignment of the unbound He-5 fragment after fragmentation of 240 MeV/nucleon He-6
- 1997
-
Ingår i: Physical Review Letters. - 1079-7114 .- 0031-9007. ; 79:2, s. 201-204
-
Tidskriftsartikel (refereegranskat)abstract
- Peripheral fragmentation of a 240 MeV/nucleon beam of the halo nucleus He-6 incident on carbon target has been studied in a kinematically complete experiment. It is found that one-neutron stripping to the unbound nucleus He-5 is the dominant fragmentation mechanism and that it leads to a spin alignment of He-5 in a plane perpendicular to the He-5 momentum vector. This is expected to be a common feature for all neutron halo nuclei.
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| 11. |
- Aleksandrov, D., et al.
(författare)
-
Invariant mass spectrum and alpha-n correlation function studied in the fragmentation of He-6 on a carbon target
- 1998
-
Ingår i: Nuclear Physics A. - 0375-9474. ; 633:2, s. 234-246
-
Tidskriftsartikel (refereegranskat)abstract
- Momentum distributions and invariant mass spectra from the breakup of He-6 ions with an energy of 240 MeV/u interacting with a carbon target have been studied. The data were used to extract information about the reaction mechanism which is influenced by the structure of He-6. It is found that the dominant reaction mechanism is a two-step process: knock out of one neutron followed by the decay of the He-5 resonance. The shape of the (alpha+n) two-body invariant mass spectrum is interpreted as mainly reflecting the 5He ground state which is a J(pi) = 3/2(-) resonance. However, no evidence for correlations between cu particles and neutrons is observed in the momentum widths of the distributions. It is demonstrated that a combined analysis of the two-body invariant mass spectrum and an appropriate correlation function may be used to determine the properties of the intermediate resonance. (C) 1998 Elsevier Science B.V.
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| 12. |
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| 13. |
- Garwicz, Martin, et al.
(författare)
-
Micro-organization of olivocerebellar and corticonuclear connections of the paravermal cerebellum in the cat
- 1996
-
Ingår i: European Journal of Neuroscience. - : Wiley. - 1460-9568 .- 0953-816X. ; 8:12, s. 2726-2738
-
Tidskriftsartikel (refereegranskat)abstract
- The olivocerebellar and corticonuclear connections of the forelimb area of the paravermal medial C3 zone were studied in the cat using a combined electrophysiological and fluorescent tracer technique. During an initial operation under barbiturate anaesthesia, lobules IV/V of the cerebellar anterior lobe were exposed and small injections of dextran amines tagged with rhodamine or fluorescein were made into areas selected from four different electrophysiologically defined parts of the zone. The inferior olive and the deep cerebellar nuclei were then scrutinized for retrogradely labelled cells and anterogradely labelled axon terminals respectively. The findings demonstrate a detailed topographical organization within the olivocerebellar projection to the medial C3 zone and provide some evidence for a topographical organization of its projection to nucleus interpositus anterior. Both projections are described at a level of resolution not previously attained in neuroanatomical studies and the results strongly support the notion of a micro-compartmentalization of cerebellar olivo-corticonuclear circuits.
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| 14. |
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| 15. |
- Guo, J.-H., et al.
(författare)
-
How the phenyle rings (benzene) act as building blocks in pi conjugated polymers
- 1998
-
Ingår i: Advanced Light Source. - Berkeley : Ernest Orlando Lawrence Berkeley National Laboratory, University of California Berkeley, California, USA. ; , s. 129-132
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Organic conjugated polymers have the electronic structure of semiconductors and can be doped to become good conductors (1). Conjugated polymers are now used as active materials in a wide variety of prototype applications such as light emitting diodes [2] and organic transistors [3,4]. Most of the interesting chemistry and physics of conjugated polymers is associated with the details of the electronic structure at the valence and conduction band edges and, in this connection, various electron spectroscopies can be used as tools for diagnosis of the relevant electronic and geometric properties....
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| 16. |
- Guo, J.-H., et al.
(författare)
-
Resonant and nonresonant x-ray scattering spectra of some poly(phenylenevinylene)s
- 1998
-
Ingår i: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 108:14, s. 5990-5996
-
Tidskriftsartikel (refereegranskat)abstract
- The electronic structure of some poly(phenylenevinylene)s have been investigated by resonant and nonresonant x-ray inelastic scattering spectroscopies. The nonresonant as well as all resonant spectra for each polymer demonstrate benzene-like features, indicating a local character of the x-ray emission in which the phenyl ring acts as a building block. Theoretical simulations of x-ray energies and intensities taking the repeat unit as a model molecule of the polymer agree with the experimental spectra fairly well. The edges of the occupied bands have been identified in the nonresonant spectra of each polymer. By subtracting the emission energy of the highest occupied molecular orbital in the nonresonant spectrum from the core excitation energy in the resonant spectrum an alternative way to determine the optical band gap is obtained. As for free benzene the outer π band in the polymer spectra show a depletion of the emission going from the nonresonant to the resonant x-ray emission spectra. It is demonstrated that this transition, which is strictly symmetry forbidden for free benzene, becomes effectively forbidden in the polymer case as a result of strong interference effects, and it is argued that this is the general case for resonant x-ray emission of conjugated polymers as far as the frozen orbital approximation holds.
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| 17. |
- Hibou, F, et al.
(författare)
-
Comparison of eta and eta ' production in the pp -> pp eta(eta ') reactions near threshold
- 1998
-
Ingår i: PHYSICS LETTERS B. - : ELSEVIER SCIENCE BV. - 0370-2693. ; 438:1-2, s. 41-46
-
Tidskriftsartikel (refereegranskat)abstract
- The total cross section of the pp --> pp eta' reaction has been measured at two energies near threshold by detecting the final protons in a magnetic spectrometer. The values obtained are about a factor of 70 less than for the corresponding eta production,
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| 18. |
- Nilsson, Thomas, 1965, et al.
(författare)
-
He-6 and neutron momentum distributions from He-8 in nuclear break-up reactions at 240 MeV/u
- 1996
-
Ingår i: Nuclear Physics A. - 0375-9474. ; 598:3, s. 418-434
-
Tidskriftsartikel (refereegranskat)abstract
- Neutron and He-6 momentum distributions from He-8 break-up reactions in a C target have been measured at 240 MeV/u. The two-neutron removal cross section was found to be sigma(-2n) = 0.27 +/- 0.03 b. The nature of the momentum distributions is interpreted in some simple reaction scenarios.
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| 19. |
- Wurzinger, R, et al.
(författare)
-
Study of the ABC enhancement in the dd ->alpha X-0 reaction
- 1999
-
Ingår i: PHYSICS LETTERS B. - : ELSEVIER SCIENCE BV. - 0370-2693. ; 445:3-4, s. 423-427
-
Tidskriftsartikel (refereegranskat)abstract
- The dd --> alpha X0 reaction at beam energies close to the eta threshold shows very strong structure in the missing mass corresponding to the ABC enhancement. The deuteron tensor analysing power Ayy, and the slope of the v
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| 20. |
- Andersson, Martin, 1970-
(författare)
-
Structural, thermal and thermodynamic properties of some Ln-Pd oxides and their behaviour as catalyst precursors
- 1999
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The structural, thermal and thermodynamic properties of some Ln-Pd oxides of the Ln4Pd07 type are presented. The main results are; (i) Reduction of Ln4Pd07, either ex-situ by CO or in-situ by a synthetic car exhaust gas, results in a materialwith catalytic activity for car exhaust gas clean-up reactions. The obtained material consists of Pd nanoparticles situated on the surface of micron-sized grains of Ln2O3 Upon heat treatment of the reduced material in air, Lu4Pd07 i srapidly re-formed. This property May be utilised for reactivation/conditioning of aged Ln4Pd07-based catalysts; (ii) The Ln4Pd07 compounds with Ln = Nd, Sm, Eu and Gd dare isostructural and have a structure which is a triclinic distortion of the monoclinic La4Pd07 type; (iii) ΔH°, and ΔS ° f values for La4Pd07 and Nd4Pd07 have been calculated by a combination of data obtained from dissolution calorimetry and thermogravimetric analysis studies; ( iv ) Carbon nanotubes, having the so-called fishbone structure, can be prepared by heat treatment o f La4Pd07 in a 20% CO/He gas mixture for an extended period of time. Nanotubes have been extracted from the obtained La203/Pd/nanotube mixture, using a wet-chemical method.
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| 21. |
- Baumann, T., et al.
(författare)
-
Longitudinal momentum distributions of C-16,C-18 fragments after one-neutron removal from C-17,C-19
- 1998
-
Ingår i: Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics. - 0370-2693. ; 439:3-4, s. 256-261
-
Tidskriftsartikel (refereegranskat)abstract
- The fragment separator FRS at GSI was used as an energy-loss spectrometer to measure the longitudinal momentum distributions of C-16,C-18 fragments after one-neutron removal reactions in C-17,C-19 impinging on a carbon target at about 910 MeV/u. The distributions in the projectile frames are characterized by a FWHM of 141 +/- 6 MeV/c for C-16 and 69 +/- 3 MeV/c for C-18. Th, results are compared with experimental data obtained at lower energies and discussed within existing theoretical models. (C) 1998 Elsevier Science B.V. AU rights reserved.
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| 22. |
- Burghart, FJ, et al.
(författare)
-
Muons and muonium in Zn-spinels
- 1997
-
Ingår i: HYPERFINE INTERACTIONS. - : BALTZER SCI PUBL BV. - 0304-3843. ; 106:1-4, s. 187-192
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- We have studied the magnetic spinel (Zn)[Fe-2]O-4 (T-N approximate to 10.5 K) and the non-magnetic spinels (Zn)[Al-2]O-4, (Zn)[Ga-2]O-4, (Zn)[ZnTi]O-4 and (Zn)[ZnSn]O-4, both with surface and decay channel muons. In (Zn)[Fe-2]O-4 the relaxation rate incre
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| 23. |
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| 24. |
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| 25. |
- Garwicz, Martin, et al.
(författare)
-
Functional organization of the intermediate cerebellum.
- 1995
-
Ingår i: Alpha and Gamma Motor Systems. - Boston, MA : Springer US. - 9780306451867 - 9781461519355 ; , s. 399-402
-
Konferensbidrag (refereegranskat)abstract
- The uniform organisation of the neuronal circuitry throughout the cerebellar cortex suggests a uniform mode of operation and thus emphasises the importance of local afferent and efferent connections in determining the function of a particular part of the cortex. Based on the organisation of these connections the cerebellar cortex of the cat is divided into about ten sagittally oriented zones (see Ito, 1984 for references). A zone is anatomically defined by its projection to a restricted part of the intracerebellar or vestibular nuclei and its climbing fibre input from a circumscribed part of the inferior olive. Some of the zones are functionally coupled in that they receive branching collaterals from common olivary neurones and in turn project to the same subdivision of the intracerebellar nuclei. Since each part of the inferior olive receives input from a specific set of spino-olivary pathways, the zones can be electrophysiologically identified by the latencies and receptive fields of climbing fibre responses evoked on peripheral stimulation. The organisation of olivary afferent and nuclear efferent connections suggests that each zone, or in some cases an ensemble of zones, controls specific motor systems.
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| 26. |
- Grdic Eliasson, Dubravka, et al.
(författare)
-
The mucosal adjuvant effects of cholera toxin and immune-stimulating complexes differ in their requirement for IL-12, indicating different pathways of action.
- 1999
-
Ingår i: European journal of immunology. - 0014-2980. ; 29:6, s. 1774-84
-
Tidskriftsartikel (refereegranskat)abstract
- Adjuvants that can improve mucosal vaccine efficacy are much warranted. In this comparative study between cholera toxin (CT) and immune-stimulating complexes (ISCOM) we found that, contrary to CT, ovalbumin (OVA)-ISCOM were poor inducers of mucosal anti-OVA IgA responses, but induced similar or better systemic immunity following oral immunizations. The addition of CT to the oral OVA-ISCOM protocol did not stimulate local anti-OVA IgA immunity, nor did it change the quality or magnitude of the systemic responses. Both vectors recruited strong innate immunity, but only OVA-ISCOM could directly induce IL-12, demonstrable at the protein and mRNA levels. CT had no inhibitory effects on lipopolysaccharide/IFN-gamma-induced IL-12 mRNA expression or IL-12 production. Furthermore, adjuvanticity of CT was unaffected in IL-12-deficient mice, while OVA-ISCOM showed partly impaired adjuvant effects by the lack of IL-12. CT abrogated the induction of oral tolerance stimulated by antigen feeding in these mice. In addition, CT did not alter TGF-beta levels, suggesting that the immunomodulating effect of CT was independent of IL-12 as well as TGF-beta production. Taken together, these findings indicate that mucosal adjuvanticity of CT and ISCOM are differently dependent on IL-12, suggesting that separate and distinct antigen-processing pathways are involved.
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| 27. |
- Grevy, S., et al.
(författare)
-
Core-breakup reactions of the halo nuclei Be-11 and Li-11: momentum distributions and shadow effects
- 1999
-
Ingår i: Nuclear Physics A. - 0375-9474. ; 650:1, s. 47-61
-
Tidskriftsartikel (refereegranskat)abstract
- The halo nuclei Be-11 and Li-11 have been studied in core-breakup reactions where the halo neutrons are expected to be released without a major distortion due to the reaction. The widths of the halo-neutron momentum distributions have been extracted in coincidence with He fragments, Gamma = 32 +/- 4 MeV/c, and Li fragments, Gamma = 42 +/- 4 MeV/c for Be-11 and with He fragments, Gamma =42+/-6 MeV/c for Li-11. The Be-11 breakup gives a very low neutron multiplicity of 0.38+/-0.09 which is a manifestation of the shadowing of the neutron in the core-breakup reaction. This value can be understood from a simple theoretical calculation, which also accounts for the observed transverse momentum widths at small angles. (C) 1999 Elsevier Science B.V.
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| 28. |
- Guo, JH, et al.
(författare)
-
Resonant and nonresonant x-ray scattering spectra of some poly(phenylenevinylene)s
- 1998
-
Ingår i: JOURNAL OF CHEMICAL PHYSICS. - 0021-9606. ; 108:14, s. 5990-5996
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The electronic structure of some poly(phenylenevinylene)s have been investigated by resonant and nonresonant x-ray inelastic scattering spectroscopies. The nonresonant as well as all resonant spectra for each polymer demonstrate benzene-like features, ind
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| 29. |
- Hornyak, G. L., et al.
(författare)
-
Dynamical Maxwell-Garnett optical modeling of nanogold-porous alumina composites : Mie and kappa influence on absorption maxima
- 1997
-
Ingår i: Nanostructured materials. - : Elsevier BV. - 0965-9773 .- 1872-9150. ; 9:1-8, s. 575-578
-
Tidskriftsartikel (refereegranskat)abstract
- Composites consisting of nanogold in porous alumina host membranes have been fabricated and characterized. Nanocluster size (11 nm to 60 nm radius) and shape (prolate to oblate) were varied experimentally. Two phenomena were responsible for the position of maximum absorption (λmax) of the composites. First, light scattering due to extrinsic electrodynamic effects became important as particle size was increased. This resulted in red shifts in λmax and is known as the Mie effect. Secondly, blue shifts were induced as particle aspect ratio was increased. We have designated shifts due to particle shape and orientation as the "kappa" effect. The two appeared to exert their influence independently. Simulations by means of the dynamical Maxwell-Garnett (DMG) expression resulted in good correlation with experimental λmax. We demonstrate again the versatility of the template method of synthesizing nanostructured materials. © 1997 Acta Metallurgica Inc.
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| 30. |
- Hornyak, G. L., et al.
(författare)
-
Effective medium theory characterization of Au/Ag nanoalloy-porous alumina composites
- 1997
-
Ingår i: Nanostructured materials. - : Elsevier BV. - 0965-9773 .- 1872-9150. ; 9:1-8, s. 571-574
-
Tidskriftsartikel (refereegranskat)abstract
- The optical constants nAl and kAl of a 50/50 volume fraction Au/Ag alloy were derived synthetically by application of a Bruggeman (BG) effective medium expression. The alloy data base was then input into a Maxwell-Garnett (MG) effective medium expression to determine the absorption maximum of the nano- alloy/insulator composite (the volume fraction of the nano-alloy was equal to 5%). The absorption maximum (λmax) of the hypothetical composite was found to be 499 nm for spherical particles and was blue-shifted relative to that of a composite containing pure gold nanospheres (499 vs. 528 nm respectively). The transmission color at this wavelength was a red-orange. λmax in the range 512 to 519 nm (Au/Ag alloy between 60/40 - 70/30 volume fraction respectively) is needed to obtain the scarlet-red exhibited by the famous Lycurgus cup of 4th century Rome (1). © 1997 Acta Metallurgica Inc.
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| 31. |
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| 32. |
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| 33. |
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| 34. |
- Kremer, B, et al.
(författare)
-
Influence of lamotrigine on progression of early Huntington disease : a randomized clinical trial.
- 1999
-
Ingår i: Neurology. - 0028-3878 .- 1526-632X. ; 53:5, s. 1000-11
-
Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To assess the efficacy of lamotrigine, a novel antiepileptic drug that inhibits glutamate release, to retard disease progression in Huntington disease (HD).BACKGROUND: Excitatory amino acids may cause selective neuronal death in HD, and lamotrigine may inhibit glutamate release in vivo.METHODS: A double-blinded, placebo-controlled study was conducted of 64 patients with motor signs of less than 5 years' duration who were randomly assigned to either placebo or lamotrigine and assessed at 0 (baseline), 12, 24, and 30 months. The primary response variable was total functional capacity (TFC) score. Secondary response variables included the quantified neurological examination and a set of cognitive and motor tests. Repeated fluorodeoxyglucose measurements of regional cerebral metabolism using PET also were included.RESULTS: Fifty-five patients (28 on lamotrigine, 27 on placebo) completed the study. Neither the primary response variable nor any of the secondary response variables differed significantly between the treatment groups. Both the lamotrigine and the placebo group deteriorated significantly on the TFC, in the lamotrigine group by 1.89 and the placebo group by 2.11 points. No effect of CAG size on the rate of deterioration could be detected.CONCLUSIONS: There was no clear evidence that lamotrigine retarded the progression of early Huntington disease over a period of 30 months. However, more patients on lamotrigine reported symptomatic improvement (53.6 versus 14.8%; p = 0.006), and a trend toward decreased chorea was evident in the treated group (p = 0.08). The study also identified various indices of disease progression, including motor tests and PET studies, that were sensitive to deterioration over time.
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| 35. |
- López-Puertas, M., et al.
(författare)
-
Non-local thermodynamic equilibrium limb radiances for the mipas instrument on Envisat-1
- 1998
-
Ingår i: Journal of Quantitative Spectroscopy and Radiative Transfer. - 0022-4073 .- 1879-1352. ; 59:3-5, s. 377-403
-
Tidskriftsartikel (refereegranskat)abstract
- An evaluation of the effects that the assumption of local thermodynamic equilibrium (LTE) has on the retrieval of pressure, temperature and the five primary target gases (O3, H2O, CH4, N2O, and HNO3) from spectra to be taken by Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) on the Envisat-1 platform has been conducted. For doing so, non-LTE and LTE limb radiances in the spectral range of 680–2275 cm−1 (4.15–14.6 μm) with a resolution of 0.05 cm−1 at tangent heights from 10 to 70 km have been computed. These calculations included the most updated non-LTE populations of a large number of vibrational levels of the CO2, O3, H2O, CH4, N2O and HNO3 molecules which cause the most prominent atmospheric infrared emissions. A discussion of the most important non-LTE effects on the limb radiances as well as on the retrievals of pressure-temperature and volume mixing ratios of O3, H2O, CH4, N2O, and HNO3 is presented, together with the most important non-LTE issues that could be studied with the future coming of MIPAS data.
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| 36. |
- Maeurer, MJ, et al.
(författare)
-
Human intestinal Vdelta1+ lymphocytes recognize tumor cells of epithelial origin
- 1996
-
Ingår i: The Journal of experimental medicine. - : Rockefeller University Press. - 0022-1007 .- 1540-9538. ; 183:4, s. 1681-1696
-
Tidskriftsartikel (refereegranskat)abstract
- gammadelta T cells can be grouped into discrete subsets based upon their expression of T cell receptor (TCR) variable (V) region families, their tissue distribution, and their specificity. Vdelta2+ T cells constitute the majority of gammadelta T cells in peripheral blood whereas Vdelta1+T cells reside preferentially in skin epithelium and in the intestine. gammadelta T cells are envisioned as first line host defense mechanisms capable of providing a source of immune effector T cells and immunomodulating cytokines such as interleukin (IL) 4 or interferon (IFN) gamma. We describe here the fine specificity of three distinct gammadelta+ tumor-infiltrating lymphocytes (TIL) obtained from patients with primary or metastatic colorectal cancer, that could be readily expanded in vitro in the presence of IL-1beta and IL-7. Irrespective of donor, these individual gammadelta T cells exhibited a similar pattern of reactivity defined by recognition of autologous and allogeneic colorectal cancer cells, renal cell cancer, pancreatic cancer, and a freshly isolated explant from human intestine as measured by cytolytic T cell responses and by IFN-gamma release. In contrast, tumors of alternate histologies were not lysed, including lung cancer, squamous cell cancer, as well as the natural/lymphocyte-activated killer cell-sensitive hematopoietic cell lines T2, C1R, or Daudi. The cell line K562 was only poorly lysed when compared with colorectal cancer targets. Target cell reactivity mediated by Vdelta1+ T cells was partially blocked with Abs directed against the TCR, the beta2 or beta7 integrin chains, or fibronectin receptor. Marker analysis using flow cytometry revealed that all three gammadelta T cell lines exhibit a similar phenotype. Analysis of the gammadelta TCR junctional suggested exclusive usage of the Vdelta1/Ddelta3/Jdelta1 TCR segments with extensive (< or = 29 bp) N/P region diversity. T cell recognition of target cells did not appear to be a major histocompatibility complex restricted or to be correlated with target cell expression of heat-shock proteins. Based on the ability of some epithelial tumors, including colorectal, pancreatic, and renal cell cancers to effectively cold target inhibit the lysis of colorectal cancer cell lines by these Vdelta1+ T cell lines, we suggest that intestinal Vdelta1+ T cell lines, we suggest that intestinal Vdelta1+ T cells are capable of recognizing cell surface Ag(s) shared by tumors of epithelial origin.
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| 37. |
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| 38. |
- Magnuson, Martin, 1965-, et al.
(författare)
-
Resonant inelastic soft X-ray scattering spectra at the nitrogen and carbon K-edges of poly(pyridine-2,5-diyl)
- 1999
-
Ingår i: Journal of Electron Spectroscopy and Related Phenomena. - 0368-2048 .- 1873-2526. ; 101-103, s. 573-578
-
Tidskriftsartikel (refereegranskat)abstract
- Resonant inelastic scattering measurements of the conjugated polymer, poly(pyridine-2,5-diyl) have been performed at the nitrogen and carbon K-edges using synchrotron radiation. For comparison, molecular orbital calculations of the spectra have been carried out with the repeat unit as a model molecule of the polymer chain. The resonant emission spectra show depletion of the π electron bands which is consistent with symmetry selection and momentum conservation rules. The depletion is most obvious in the resonant inelastic scattering spectra of carbon while the nitrogen spectra are dominated by lone pair n orbital emission of σ symmetry and are less excitation energy dependent. By comparing the measurements to calculations an isomeric dependence of the resonant spectra is found giving preference to two of the four possible isomers in the polymer.
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| 39. |
- Magnuson, Martin, 1965-, et al.
(författare)
-
The electronic structure of poly(pyridine-2,5-diyl) investigated by soft X-ray absorption and emission spectroscopies
- 1998
-
Ingår i: Chemical Physics. - 0301-0104 .- 1873-4421. ; 237:3, s. 295-304
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Tidskriftsartikel (refereegranskat)abstract
- The electronic structure of the poly-pyridine conjugated polymer has been investigated by resonant and non-resonant inelastic X-ray scattering and X-ray absorption spectroscopies using synchrotron radiation. The measurements were made for both the carbon and nitrogen contents of the polymer. The analysis of the spectra has been carried out in comparison with molecular orbital calculations taking the repeat-unit cell as a model molecule of the polymer chain. The simulations indicate no significant differences in the absorption and in the non-resonant X-ray scattering spectra for the different isomeric geometries, while some isomeric dependence of the resonant spectra is predicted. The resonant emission spectra show depletion of the electron bands in line with symmetry selection and momentum conservation rules. The effect is most visual for the carbon spectra; the nitrogen spectra are dominated by lone pair n orbital emission of symmetry and are less frequency dependent.
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| 40. |
- Malmsten, Martin, et al.
(författare)
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Adsorption of complement protein C3 at polymer surfaces and the demonstration of a specific binding of factor B by adsorbed C3
- 1996
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Ingår i: Journal of Colloid and Interface Science. - : Elsevier BV. - 0021-9797 .- 1095-7103. ; 179:1, s. 163-172
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Tidskriftsartikel (refereegranskat)abstract
- The adsorption of C3 at poly(methyl methacrylate) (PMMA) and poly(styrene) (PS) surfaces was investigated within situellipsometry and compared to that at (hydrophilic and negatively charged) silica and (hydrophobic) methylated silica. The adsorption of C3 at PMMA was higher than that at PS, while the adsorbed layer thickness was the same for the two surfaces. For both PMMA and PS the adsorbed layer thickness (10 ± 2 nm) corresponds rather closely to that of end-on oriented C3 molecules. The adsorption of C3 at PMMA and PS was found to be intermediate between that at silica and methylated silica, although the adsorbed layer thickness was similar for all surfaces. The competitive adsorption among C3, human serum albumin (HSA), and factor B was investigated with ellipsometry and total internal reflection fluorescence spectroscopy (TIRF). Addition of HSA after C3 preadsorption resulted in fractional C3 desorption for both PMMA and PS. Factor B deposition at PS after preadsorption of C3 and blocking with HSA was found to be largely due to specific binding to C3/C3b, while in the case of PMMA, factor B was largely accumulated through passive (displacement) adsorption.
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| 41. |
- Manuilova, R.O., et al.
(författare)
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Modelling of non-LTE limb spectra of i.r. ozone bands for the MIPAS space experiment
- 1998
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Ingår i: Journal of Quantitative Spectroscopy and Radiative Transfer. - 0022-4073 .- 1879-1352. ; 59:3-5, s. 405-422
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Tidskriftsartikel (refereegranskat)abstract
- A new model for calculating the populations of the ozone vibrational states under non-LTE (Local Thermodynamic Equilibrium) conditions is presented. In the model, 23 vibrational levels of the O3 molecule, as well as three vibrational levels of the O2 molecule and two vibrational levels of the N2 molecule, are considered. The radiative transfer at the break-down of LTE was treated explicitly for 150 000 ro-vibrational transitions. The populations obtained were used to calculate limb radiances in various spectral regions of the 4.8 and 9.6 μm bands. Test retrievals of O3 vertical volume mixing ratio (VMR) profiles with a radiance model disregarding non-LTE were performed in order to assess the potential impact of non-LTE effects on the retrieval of the O3 abundances from MIPAS (Michelson Interferometer for Passive Atmospheric Sounding) measurements.
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| 42. |
- Marques, F. M., et al.
(författare)
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Neutrons from the breakup of C-19
- 1996
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Ingår i: Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics. - 0370-2693. ; 381:4, s. 407-412
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Tidskriftsartikel (refereegranskat)abstract
- Neutrons arising from the breakup of a 30 MeV/nucleon C-19 beam on a tantalum target have been measured using the 98 element array DEMON. A narrow, forward peaked neutron angular distribution, with a corresponding momentum spread considerably smaller than those measured simultaneously for N-21, O-22 and F-24 was observed for charged fragments with Z
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| 43. |
- Michaëlsson, E., et al.
(författare)
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Macrophages, but not dendritic cells, present collagen to T cells
- 1995
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Ingår i: European Journal of Immunology. - : Wiley. - 0014-2980 .- 1521-4141. ; 25:8, s. 2234-2241
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Tidskriftsartikel (refereegranskat)abstract
- Dendritic cells, such as epidermal Langerhans cells, play a crucial role for the antigen-specific priming of T cells. We have addressed the question whether dendritic cells present collagen, a major protein component in tissues through which dendritic cells migrate, i.e. the basement membrane, dermis, and synovial tissue. Langerhans cells, spleen cells and peritoneal macrophages were compared for antigen-presenting capacity using a panel of mouse T cell hybridomas reactive with different determinants on type II collagen, myelin basic protein, ovalbumin and pepsin. Langerhans cells did not present any of the type II collagen determinants, unless the antigen was administered as a 15-mer peptide, but did present myelin basic protein, ovalbumin and pepsin. Spleen cells and peritoneal macrophages, in contrast, presented all type II collagen determinants. This biased antigen presentation was also observed when Langerhans cells were pulsed with antigen in vivo. The inability to present type II collagen is related to the collagen sequence as such, since both native type II collagen, type II collagen alpha chains, as well as a type II collagen determinant incorporated in type I collagen, were not presented by Langerhans cells. In addition, granulocyte/macrophage colony-stimulating factor-expanded blood dendritic cells displayed the same biased antigen presentation, suggesting that the inability to present collagen is not restricted to dendritic cells localized in epidermis. B cell-deficient mice could prime a type II collagen-reactive T cell response, thus excluding B cells as obligatory antigen-presenting cells for the priming of collagen-reactive T cells. We suggest that neither Langerhans cells nor B cells, but macrophages are the primary antigen-presenting cells in the immune response towards type II collagen.
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| 44. |
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| 45. |
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| 46. |
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| 47. |
- Schiessl, W, et al.
(författare)
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Magnetic properties of the ZnFe2O4 spinel
- 1996
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Ingår i: PHYSICAL REVIEW B-CONDENSED MATTER. - : AMER INST PHYSICS. ; 53:14, s. 9143-9152
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Using neutron diffraction (ND), muon-spin rotation/relaxation (mu SR), and Fe-57 and Zn-67 Mossbauer spectroscopy (MS) we investigated magnetic properties of the normal spinel ZnFe2O4. Inversion is below limits of detection in samples which were slowly co
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| 48. |
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| 49. |
- Söderlund, Erika, et al.
(författare)
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Heat Recovery Enhancement and Operational Issues of a 200 kWeFuel Cell Cogeneration Plant
- 1999
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Ingår i: ASME 1999 International Mechanical Engineering Congress and Exposition, IMECE 1999. - : American Society of Mechanical Engineers (ASME). ; , s. 297-303
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Konferensbidrag (refereegranskat)abstract
- This study presents some of the experiences gained during a two year operational period of a decentralized fuel cell cogeneration plant installed in southern Sweden. Various modifications to the system are described, most notably a plume eliminator for the reduction of an undesirable vapor cloud emitted by the original system. Aside from vapor cloud elimination, the plume eliminator allows for more efficient plant operation, as a larger fraction of the system cooling requirements can be shifted to the district heating system. In-field measurements show a 17 to 26% increase in district heat production with use of the plume eliminator, depending upon the season of operation (winter or summer). The study also presents two options for added heat recovery, which are employed in conjunction with the plume eliminator: An air preheater module; and an air preheater/humidifier module. Calculations show that air preheating has a small but measurable impact on heat recovery (an additional 8% gain), while combined air preheating and humidification allows for nearly a 50% increase in district heat production.
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| 50. |
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