| 26. |
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| 27. |
- Lindquist, Ulf, 1950-
(författare)
-
Structural studies of some capsular polysaccharides from Streptococcus pneumoniae and a study of o̲-formyl groups in carbohydrates
- 1985
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Structural studies of the capsular polysaccharides from Streptococcus pneumoniae type 4, 5 and 17A are summarized. The principal methods in these studies were n.m.r. spectroscopy, méthylation analysis and specific degradations. In Streptococcus pneumoniae type 5 a new sugar was discovered and identified as 2-acetamido-2,6-dideoxy-D-Mlo-hexos- 4- ulose . 1 1 3 H- and C-n.m.r. studies of the extracellular polysaccharides elaborated by Klebsiella types K2, K54, K63 and of model substances containing O-formyl groups are discussed. Fast atom bombardment mass spectrometry of oligosaccharides obtained from K54 indicate that the polysaccharide does not contain O-formyl groups, contrary to what has been reported.
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| 28. |
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| 29. |
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| 30. |
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| 31. |
- Magnusson, Göran
(creator_code:cre_t)
-
Enantiomerically pure tetrahydrofuran compounds and a method for their preparation
- 1989
-
Patent (övrigt vetenskapligt/konstnärligt)abstract
- The present invention relates to novel enantiomerically pure intermediary compounds containing specifically substituted tetrahydrofuran structures as well as a method for preparing such intermediary compounds of formula (I), in which the carbon atom in the 2-position has (R)- or (S)-configuration; the substituents in the 2- and 3-positions are trans-related; the substituents in the 3- and 4-positions are cis- or trans-related; X is oxygen, sulphur or -SO2-; R1 is a sterically hindering protecting group; R2 is an organic residue; and the wavy line denotes a connection to the rest of the molecule; the method comprising reacting a compound containing partial formula (II), in which the carbon atom in the 2-position has (R)- or (S)-configuration, and X, R1 and the wavy line are as defined above, with an organic anion R2-, where R2 is as defined above, as well as the compounds containing partial formula (I) themselves. The compounds preferably have formula (Ia), in which R3 is hydrogen or an organic residue and the stereochemistry and the other variables are as defined above.
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| 32. |
- Oscarson, Stefan, 1953-
(författare)
-
Synthesis of some oligosaccharides with D-galacto- and D-gluco-configuration and reductive opening of carbo-hydrate acetals
- 1985
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Syntheses of the following oligosaccharides, required for immunological studies. are discussed: £-trifluoroacetamidophenyl O-a-D-glucopyranosyl-(1+4)-a-D-galactopyranoside, ß-trifluoroacetamidophenyl O-a-D-glucopyranosyl-(1 + 6)-a-D-galactopyranoside, 8-methoxy- carbonyloct-1-yl 0-a-D-galactopyranosyl-(1+3)-fi-ß~9"9alact°Pyranosyl- (1+4)-2-acetamido-2-deoxy-ß-D-glucopyranoside, methyl û-a-D-fuco- pyranosyl-(1+4)-ß-D-galactopyranoside, methyl û-a-D-galactopyranosyl- (1+4)-ß-D-fucopyranoside and methyl ß-a-D-fucopyranosyl-(1+4)-ß-D- fucopyranoside. A synthesis of a sucrose derivative suitable for selective acylation at OH-2, OH-3 and/or OH-4 is also described. Furthermore, reductive opening of acrolein acetals with sodium cyanoborohydride/hydrogen chloride and of benzylidene acetals with borane trimethylamine/aluminium chloride is examined. The dependency of regioselectivity on solvent and reagents is investigated.
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| 33. |
- Palm, Jonas
(författare)
-
Konservering av papper
- 1987
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Ingår i: Kulturminnesvård. - Stockholm : Riksantikvarieämbetet. - 0346-9077. ; :4-5, s. 52-54
-
Tidskriftsartikel (populärvet., debatt m.m.)abstract
- Jonas Palm vid Uppsala universitetsbibliotek skildrar papperets historia och berättar om dagens konserveringsproblem.
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| 34. |
- Pettersson, Gösta, et al.
(författare)
-
A mathematical model of the Calvin photosynthesis cycle
- 1988
-
Ingår i: European Journal of Biochemistry. - : Wiley. - 0014-2956 .- 1432-1033. ; 175:3, s. 661-672
-
Tidskriftsartikel (refereegranskat)abstract
- A mathematical model is presented for photosynthetic carbohydrate formation in C3 plants under conditions of light and carbon dioxide saturation. The model considers reactions of the Calvin cycle with triose phosphate export and starch production as main output processes, and treats concentrations of NADPH, NAD+, CO2, and H+ as fixed parameters of the system. Using equilibrium approximations for all reaction steps close to equilibrium, steady‐state and transient‐state relationships are derived which may be used for calculation of reaction fluxes and concentrations of the 13 carbohydrate cycle intermediates, glucose 6‐phosphate, glucose 1‐phosphate, ATP, ADP, and inorganic (Ortho)phosphate. Predictions of the model were examined with the assumption that photosynthate export from the chloroplast occurs to a medium containing orthophosphate as the only exchangeable metabolite. The results indicate that the Calvin cycle may operate in a single dynamically stable steady state when the external concentration of orthophosphate does not exceed 1.9 mM. At higher concentrations of the external metabolite, the reaction system exhibits overload breakdown; the excessive rate of photosynthate export deprives the system of cycle intermediates such that the cycle activity progressively approaches zero. Reactant concentrations calculated for the stable steady state that may obtain are in satisfactory agreement with those observed experimentally, and the model accounts with surprising accuracy for experimentally observed effects of external orthophosphate on the steady‐state cycle activity and rate of starch production. Control analyses are reported which show that most of the non‐equilibrium enzymes in the system have a strong regulatory influence on the steady‐state level of all of the cycle intermediates. Substrate concentration control coefficients for cycle enzymes may be positive, such that an increase in activity of an enzyme may raise the steady‐state concentration of the substrate is consumes. Under optimal external conditions (0.15–0.5 mM orthophosphate), reaction flux in the Calvin cycle is controlled mainly by ATP synthetase and sedoheptulose bisphosphatase; the cycle activity approaches the maximum velocity that can be supported by the latter enzyme. At lower concentrations of external orthophosphate the cycle activity is controlled almost exclusively by the phosphate translocator. At high external orthophosphate concentrations the phosphate translocator resumes predominant control, but also other non‐equilibrium enzymes gain strong flux control with one notable exception: ribulosebisphosphate carboxylase has no significant regulatory influence on the cycle activity under conditions of light and CO2 saturation, nor does it control the concentration of any cycle intermediate other than its substrate.
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| 35. |
- Rappe, Christoffer, et al.
(författare)
-
Preface
- 1986. - 1
-
Ingår i: Chlorinated dioxins and dibenzofurans in perspective. - Boca Raton : CRC Press. - 9781315891545 - 9781351070645 ; , s. iii-vii
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- This volume was developed from the proceedings of a symposium held in Miami Beach, at the 189th National Meeting of the American Chemical Society. It is the result of the combined efforts of many experts whose efforts have advanced our knowledge of the production, analysis, distribution, effects and control of chlorinated dioxins, dibenzofurans and related compounds. This is the third in a series of publications originating from current technology presented at national meetings of the American Chemical Society. Using this forum as a catalyst, researchers from all over the world came together to present and discuss their data and plan future work in this rapidly developing and sometimes highly emotional technical area.
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| 36. |
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| 37. |
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| 38. |
- Rehnberg, Nicola, et al.
(författare)
-
Total synthesis of the lignans (-)- and (+)-burseran, (-)-cubebin, and (-)-hinokinin by diastereoselective conjugate addition of benzyl anions to 2-(R) and (s)-benzyloxy-2,5-dihydro-4-(3,4-methylenedioxybenzoyl)furan
- 1988
-
Ingår i: Tetrahedron Letters. - : Elsevier BV. - 0040-4039. ; 29:29, s. 3599-3602
-
Tidskriftsartikel (refereegranskat)abstract
- 1,2-Addition of 3,4-methylenedioxymagnesium bromide to 2-(R) and (S)-benzyloxy-2,5-dihydro-4-furancarboxaldehyde, followed by oxidation, gave the title ketones (3r and 3s). Conjugate addition of the anions of 3,4,5-trimethoxy- and 3,4-methylenedioxybenzaldehyde diphenylthioacetal to 3r and 3s and Raney-nickel desulfurisation, followed by hydrogenolysis under various conditions, gave the title lignans. (-)-Burseran was prepared in >98% diastereomeric excess.
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| 39. |
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| 40. |
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| 41. |
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| 42. |
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| 43. |
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| 44. |
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| 45. |
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| 46. |
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| 47. |
- v. d. Lieth, C. W., et al.
(författare)
-
PEPCRE: an interactive program to create, manipulate and display oligopeptides
- 1987
-
Ingår i: Journal of Molecular Graphics and Modelling. - : Elsevier BV. - 1093-3263 .- 0263-7855. ; 5:3, s. 119-125
-
Tidskriftsartikel (refereegranskat)abstract
- PEPCRE is an interactive computer graphics program for the rapid construction, manipulation and display of oligopeptides. Essentially any desired conformation of an oligopeptide can be constructed in a simple and straightforward manner. The program provides various display and output possibilities. It is user-friendly and is written in FORTRAN 77 for use on inexpensive, monochrome graphics terminals.
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| 48. |
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