M. Andersson

Structural studies of the O-antigenic polysaccharide of Escherichia coli O86, which possesses blood-group B activity

The O-specific side-chains of the lipopolysaccharide from Escherichia coli O86:K2:H2 have been investigated using n.m.r. spectroscopy, methylation analysis, and specific degradations, and shown to be composed of the pentasaccharide repeating-unit (formula; see text) which represents the biological repeating-unit. The blood-group B activity was confirmed by an enzyme-linked immunosorbent assay.

Structural studies of the capsular polysaccharide from streptococcus pneumoniae type 2, a reinvestigation

The structure of the capsular polysaccharide from Streptococcus pneumoniae type 2 has been reinvestigated, specific degradations and n.m.r. spectroscopy being the main methods used. It is concluded that the polysaccharide is composed of hexasaccharide repeating-units having the following structure, which differs from that previously proposed. formula; see text)

Synthesis ofO-glycopyranosyl-N-hydroxysuccinimides of glucose and lactose and their opening by nucleophiles into prespacer glycosides

O-Glycopyranosyl-N-hydroxysuccinimides of glucose and lactose have been synthesized. Peracetylated sugars, acetobromo sugars and benzoylated thioethyl glycosides have been used as precursors. With boron trifluoride etherate in dichloromethane, peracetylated sugars gave predominantly the β anomer. Trimethylsilyl trifluoromethanesulfonate in nitromethane, however, gave predominantly the α anomer. Treatment of the acetylatedO-glucopyranosyl-N-hydroxysuccinimide with various nucleophiles (methoxide, hydroxide and pentylamine) gave the corresponding deacetylatedN-(succinyl)glucopyranosylhydroxylamines in almost quantitative yield. These derivatives are suitable for the formation of glycoconjugates or attachment of carbohydrates to solid phases using the opened succinimide as linking arm.

Synthesis of oligosaccharides with oligoethylene glycol spacers and their conversion into glycoconjugates usingN,N,N′,N″-tetramethyl(succinimido)uronium tetrafluoroborate as coupling reagent

Glycosides of glucose and lactose with di- and tetraethylene glycols, transformed into bifunctional (alcohol, ester) spacer molecules, have been synthesized. After deprotection, these spacer glycosides, containing a free carboxyl group, have been transformed efficiently into glycoconjugates usingN,N,N′,N″-tetramethyl(succinimido)uronium tetrafluoroborate (TSTU) for the formation of an active ester.

Isospin resolved double pion production in the reaction p+d→3He+2π

Abstract Neutral and charged two-pion production in p+d→ 3 He+2 π reactions has been studied at CELSIUS at a proton beam energy of 477 MeV. The total cross section for double pion production is 0.22±0.03 μ b. The ratio of the cross sections for the production of charged pion pairs with isospin T =1 and T =0 was determined to be σ ( π + π − ; T =1)/ σ ( π + π − ; T =0)=1.4±0.4.

Synthesis of, and NMR and CD studies on, methyl 4-O-[(R)- and (S)-1-carboxyethyl]-α-L-rhamnopyranoside and methyl 6-O-[(R)- and (S)-1-carboxyethyl]-α-D-galactopyranoside

Abstract The title compounds were prepared by condensation of a suitably protected monosaccharide and ( R )- or ( S )-2-chloropropanoic acid. Characterization by 1 H and 13 C NMR spectroscopy revealed minor chemical shift differences between the diastereomers. CD spectra showed differences between the ( R )- and ( S )-1-carboxyethyl substituted monosaccharides, thereby facilitating determination of the absolute configuration of the substituent.

Pionic fusion to a halo state, the d(α,6Li∗)π0 reaction studied close to threshold

Abstract The d(α,6Li ∗ 3.56 )π0 reaction has been studied at Ec.m.=1.2 and 1.9 MeV above threshold with an alpha-particle beam incident on a deuterium cluster-jet target in CELSIUS. Complete differential cross sections were measured at both energies, integrated to σ=228±6+70 nb and 141±12+42 nb respectively. Observed large anisotropies are discussed in relation to the cluster structure of the 6Li ∗ halo.

The observation of deeply bound pionic states of xenon produced in the d + Xenat → Xeπ−bound + 3He reaction

Abstract We report on a search at the CELSIUS accelerator for deeply bound pionic states of xenon produced in the Xe nat. (d, 3 He)Xe π−bound reaction at E d = 500 MeV. In the 3 He energy spectrum two peaks are observed corresponding to the production of pionic atoms in the 1s state in even and odd isotopes respectively.

Pionic Fusion Study of the Halo Nucleus 6He in the Reaction d + 14N -g 6He + pi+ at CELSIUS

The halo nucleus 6He has been studied in a pionic fusion experiment at the CELSIUS storage ring facility in Uppsala. The 6He nuclei were produced in reactions with a deuteron beam incident on a 4He jet target 0.9–5.4 MeV above threshold in the center-of-mass frame. The 6He ions were detected in a ΔE-E solid-state detector telescope inserted into the CELSIUS ring. The aim of the experiment was to investigate, in particular, the high-momentum part of the halo wave function by measuring the total and differential cross sections of the reaction d+4He→6He+π+.

Pionic Fusion Study of the halo analogue state6Li

The isobaric analogue state of the ground state of the halo nucleus6He,6Li* has been studied in a pionic fusion experiment at the CELSIUS storage ring facility in Uppsala, Sweden. This was the first of two proposed experiments with the aim to study the high momentum part of the wave functions of the halo nuclei6He and6Li (0+, T=1). The Li nuclei were produced in inverse kinematics reactions with alpha particles incident on a deuterium cluster jet target. The6Li ions were detected in a zero-degree spectrometer situated in the fourth quadrant of the CELSIUS ring. The measurement was done for three different beam energies corresponding to 5.4, 2.2 and 1.5 MeV above threshold in the c.m. The cross-sections slowly increase with beam energy from 95 nb at the lowest energy to about 250 nb at 5.4 MeV above threshold.