| 1. |
- Bässler, M., et al.
(författare)
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Beam line I411 at MAX II - Performance and first results
- 2001
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - 0168-9002. ; 469:3, s. 382-393
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Tidskriftsartikel (refereegranskat)abstract
- We report on the characteristics and first results from the soft X-ray beam line I411, based on an undulator at the third generation synchrotron facility MAX II, Sweden. The beam line is designed for high-resolution, angle-resolved electron spectroscopy on gases, liquids and solids. Main components are the modified SX700 monochromator and the end station, both of which were previously used at beam line 51 at MAX I. The end station is equipped with a rotatable SES-200 hemispherical electron-analyser. Before the end station, a one-metre section is reserved for exchangeable experimental set-ups. The usable photon energy range is 50-1500 eV and the photon flux is two orders of magnitudes higher compared to beam line 51. At 400 eV a resolving power of about 5700 in the first order of the monochromator grating could be obtained. In gas phase, a total electron energy resolution of 16 meV has been achieved. Detailed results on the undulator performance, flux, photon and electron energy resolution as well as some technical details are presented here. As an example of the capabilities of the beam line I411, we present the fully vibrationally resolved Auger resonant Raman electron spectrum of gas-phase N 2.
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| 2. |
- Noresson, A. L., et al.
(författare)
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Designing interactions by control of protein-ligand complex conformation : Tuning arginine-arene interaction geometry for enhanced electrostatic protein-ligand interactions
- 2018
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Ingår i: Chemical Science. - : Royal Society of Chemistry (RSC). - 2041-6520 .- 2041-6539. ; 9:4, s. 1014-1021
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Tidskriftsartikel (refereegranskat)abstract
- We investigated galectin-3 binding to 3-benzamido-2-O-sulfo-galactoside and -thiodigalactoside ligands using a combination of site-specific mutagenesis, X-ray crystallography, computational approaches, and binding thermodynamics measurements. The results reveal a conformational variability in a surface-exposed arginine (R144) side chain in response to different aromatic C3-substituents of bound galactoside-based ligands. Fluorinated C3-benzamido substituents induced a shift in the side-chain conformation of R144 to allow for an entropically favored electrostatic interaction between its guanidine group and the 2-O-sulfate of the ligand. By contrast, binding of ligands with non-fluorinated substituents did not trigger a conformational change of R144. Hence, a sulfate-arginine electrostatic interaction can be tuned by the choice of ligand C3-benzamido structures to favor specific interaction modes and geometries. These results have important general implications for ligand design, as the proper choice of arginine-aromatic interacting partners opens up for ligand-controlled protein conformation that in turn may be systematically exploited in ligand design.
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| 3. |
- Odham, G., et al.
(författare)
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Model system for studies of microbial dynamics at exuding surfaces such as the rhizosphere.
- 1986
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Ingår i: Applied and Environmental Microbiology. - 0099-2240. ; 52:1, s. 191-196
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Tidskriftsartikel (refereegranskat)abstract
- An autoclavable all-glass system for studying microbial dynamics at permeable surfaces is described. Standard hydrophobic or hydrophilic membranes (46-mm diameter) of various pore sizes were supported on a glass frit through which nutrient solutions were pumped by a peristaltic pump. The pump provided a precisely controlled flow at speeds of 0.5 to 500 ml of defined or natural cell exudates per h, which passed through the membrane into a receiving vessel. The construction allowed a choice of membranes, which could be modified. The system was tested with a bacterium, isolated from rape plant roots (Brassica napus L.), that was inoculated on a hydrophilic membrane filter and allowed to develop into a biofilm. A defined medium with a composition resembling that of natural rape root exudate was pumped through the membrane at 0.5 ml/h. Scanning electron microscopic examinations indicated that the inoculum formed microcolonies embedded in exopolymers evenly distributed over the membrane surface. The lipid composition and content of poly-beta-hydroxybutyrate in free-living and adhered cells were determined by gas chromatography. The bacterial consumption of amino acids in the exudate was also studied.
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| 4. |
- Bässler, M., et al.
(författare)
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Soft x-ray undulator beam line 1411 at MAX-II for gases, liquids and solid samples
- 1999
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Ingår i: Journal of Electron Spectroscopy and Related Phenomena. - : Elsevier BV. - 0368-2048. ; 101-103, s. 953-957
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Tidskriftsartikel (refereegranskat)abstract
- We report on the build-up of the new undulator beam line 1411 at the third-generation synchrotron radiation facility MAX II in Lund, Sweden. This beam line is based on an upgraded version of the modified SX700-monochromator and the end station which were installed previously at beam line 51 at MAX I. The end station is equipped with a rotatable Scienta hemispherical electron-analyser making angle-resolved high resolution electron spectroscopy possible for various kinds of samples. The beam line performance will be considerably improved on MAX II due to a new undulator and the superior light source properties, e.g. the small vertical electron beam size. Undulator spectra have been measured and estimates of the photon flux at the experiment and the expected energy resolution are presented. The parameters for a new refocusing mirror were defined by ray tracing using the beam waist of the undulator. The beam line length was extended by 1 m to offer additional space for exchangeable experimental chambers.
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| 5. |
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| 6. |
- Gunnarsson, T., et al.
(författare)
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Importance of leaf litter fragmentation for bacterial growth
- 1988
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Ingår i: Oikos. - : JSTOR. - 0030-1299. ; 52:3, s. 303-308
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Tidskriftsartikel (refereegranskat)abstract
- Four fragment size groups of maple leaf litter (Acer platanoides) were leached with sterile water. The fragments and leachates were inoculated with bacteria isolated from maple leaf litter and bacterial activity and growth were determined. About 80-90% of the dissolved organic carbon (DOC) released from the leaf fragments was released during the 1st day; the release was negatively correlated with fragment size. The 2nd day the correlation became positive whereas no correlation was found during days 3-7. Contents of DOC and phenolics in leachates were positively correlated. Release of chemical substances and not the surface area in itself influences bacterial growth and activity on fragmented maple leaf litter. -from Authors
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| 7. |
- Hellstrom-Lindberg, E., et al.
(författare)
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A validated decision model for treating the anaemia of myelodysplastic syndromes with erythropoietin + granulocyte colony-stimulating factor : Significant effects on quality of life
- 2003
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Ingår i: British Journal of Haematology. - : Wiley. - 0007-1048 .- 1365-2141. ; 120, s. 1037-
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Tidskriftsartikel (refereegranskat)abstract
- We have published previously a prototype of a decision model for anaemic patients with myelodysplastic syndromes (MDS), in which transfusion need and serum erythropoietin (S-Epo) were used to define three groups with different probabilities of erythroid response to treatment with granulocyte colony-stimulating factor (G-CSF) + Epo. S-Epo = 500 U/l and a transfusion need of < 2 units/month predicted a high probability of response to treatment, S-Epo > 500 U/l and =2 units/month for a poor response, whereas the presence of only one negative prognostic marker predicted an intermediate response. A total of 53 patients from a prospective study were included in our evaluation sample. Patients with good or intermediate probability of response were treated with G-CSF + Epo. The overall response rate was 42% with 28.3% achieving a complete and 13.2% a partial response to treatment. The response rates were 61% and 14% in the good and intermediate predictive groups respectively. The model retained a significant predictive value in the evaluation sample (P < 0.001). Median duration of response was 23 months. Scores for global health and quality of life (QOL) were significantly lower in MDS patients than in a reference population, and fatigue and dyspnoea was significantly more prominent. Global QOL improved in patients responding to treatment (P = 0.01). The validated decision model defined a subgroup of patients with a response rate of 61% (95% confidence interval 48-74%) to treatment with G-CSF + Epo. The majority of these patients have shown complete and durable responses.
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| 8. |
- Lager, Erik, et al.
(författare)
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Diels-Alder adducts derived from the natural phthalide Z-ligustilide
- 2007
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Ingår i: Tetrahedron Letters. - : Elsevier BV. - 0040-4039. ; 48:24, s. 4215-4218
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Tidskriftsartikel (refereegranskat)abstract
- Z-Ligustilide, a naturally occurring phthalide isolated from Ligusticum porteri, underwent Diels-Alder reactions with different dienophiles yielding novel tricyclic products with potentially interesting biological properties. Where selectivity was possible, the reactions performed showed regio- and stereoselectivity. The experimental results with ethyl acrylate were compared with the selectivity predicted by ab initio calculations.
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| 9. |
- Madar Johansson, Miralda, et al.
(författare)
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The binding mechanism of the virulence factor Streptococcus suis adhesin P subtype to globotetraosylceramide is associated with systemic disease
- 2020
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Ingår i: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 295:42, s. 14305-14324
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Tidskriftsartikel (refereegranskat)abstract
- Streptococcus suis is part of the pig commensal microbiome but strains can also be pathogenic, causing pneumonia and meningitis in pigs as well as zoonotic meningitis. According to genomic analysis, S. suis is divided into asymptomatic carriage, respiratory and systemic strains with distinct genomic signatures. Because the strategies to target pathogenic S. suis are limited, new therapeutic approaches are needed. The virulence factor S. suis adhesin P (SadP) recognizes the galabiose Gal alpha 1-4Gal-oligosaccharide. Based on its oligosaccharide fine specificity, SadP can be divided into subtypes P-N and P-O. We show here that subtype P-N is distributed in the systemic strains causing meningitis, whereas type P-O is found in asymptomatic carriage and respiratory strains. Both types of SadP are shown to predominantly bind to pig lung globotriaosylceramide (Gb3). However, SadP adhesin from systemic subtype P-N strains also binds to globotetraosylceramide (Gb4). Mutagenesis studies of the galabiose-binding domain of type P-N SadP adhesin showed that the amino acid asparagine 285, which is replaced by an aspartate residue in type P-O SadP, was required for binding to Gb4 and, strikingly, was also required for interaction with the glycomimetic inhibitor phenylurea-galabiose. Molecular dynamics simulations provided insight into the role of Asn-285 for Gb4 and phenylurea-galabiose binding, suggesting additional hydrogen bonding to terminal GalNAc of Gb4 and the urea group. Thus, the Asn-285-mediated molecular mechanism of type P-N SadP binding to Gb4 could be used to selectively target S. suis in systemic disease without interfering with commensal strains, opening up new avenues for interventional strategies against this pathogen.
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| 10. |
- Marinho, R. R.T., et al.
(författare)
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Interference between direct and resonant channels in near-resonance photoemission in argon
- 2001
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Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics. - 1050-2947. ; 63:3, s. 325141-325145
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Tidskriftsartikel (refereegranskat)abstract
- The photoelectron spectra of argon was demonstrated during resonant photoemissions. The interference effects of the photoelectron spectra of argon was monitored by following the intensity of final states through resonant and direct channels. The need for a unified one-description of the ionization through a direct and core-excitation mediated channel was described.
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