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| 2. |
- Baeckstroem, P., et al.
(författare)
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Convenient Method for the Synthesis of Lineatin, a Pheromone Component of Trypodendron-Lineatum
- 1991
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Ingår i: Journal of Organic Chemistry. - : American Chemical Society (ACS). - 0022-3263 .- 1520-6904. ; 56:10, s. 3358-3362
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Tidskriftsartikel (refereegranskat)abstract
- Synthesis of racemic lineatin (1), a pheromone component of Trypodendron lineatum, is described. Condensation of 5-methyl-5-hexen-2-one (2) and triethyl phosphonoacetate with LiN(SiMe3)2 gave esters 3, which upon hydrolysis gave acids 4a-f. The bicyclo[3.2.0] ring compounds 5 and 6 were obtained via an intramolecular [2 + 2] addition by refluxing underivatized carboxylic acids 4a-f with NaOAc and Ac2O. Compound 5 was isomerized to the thermodynamically more stable isomer 6 using a Pd/C catalyst activated with hydrogen. Reduction of 6 with LiAlH4 gave the endo and exo isomers 7a and 7b (4:1). Isolation of the alcohol 7a followed by acetylation gave 8. Subsequent oxidation with OsO4 and methylmorpholine N-oxide gave diol 9. Cleavage of 9 with H5IO6 in diethyl ether gave keto aldehyde 10, which was converted to keto acetal 11. Treatment of 11 with MeMgBr followed by acidic workup gave 1. The overall efficiency is approximately 20%.
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| 3. |
- Chachaty, C, et al.
(författare)
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Influence of the polar head size on the dynamics of micellized surfactants
- 1991
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Ingår i: Journal of Physical Chemistry A. - 1089-5639 .- 1520-5215. ; 95, s. 3830-3836
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Tidskriftsartikel (refereegranskat)abstract
- The dynamics of micellized quaternary ammonium surfactants has been investigated by means of the frequency dependence of the 13C longitudinal relaxation rates. Trimethyl-, triethyl-, and tributyldodecylammonium bromides were used to systematically vary the bulk of the polar head and examine its influence on the internal and overall motions of the surfactants. The relaxation data were analyzed by means of the two-step model and of a rotational jump model relevant to the trans-gauche isomerizations about the bonds. In the case of the trimethyldodecyl--ammonium bromide an excellent agreement is obtained by the two-step model as the vicinity of the nitrogen is well above the values expected for methylene groups. The jump model shows that this behavior results from a slowing of the internal motions beyond the domain of validity of the two-step model.
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| 4. |
- Grubin, C. E., et al.
(författare)
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A novel radioligand binding assay to determine diagnostic accuracy of isoform-specific glutamic acid decarboxylase antibodies in childhood IDDM
- 1994
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Ingår i: Diabetologia. - 0012-186X. ; 37:4, s. 344-350
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Tidskriftsartikel (refereegranskat)abstract
- Insulin-dependent diabetes mellitus (IDDM) is associated with autoreactivity against GAD but the diagnostic sensitivity (positivity in disease) and specificity (negativity in health) of isoform-specific GAD antibodies have yet to be defined in assay systems suitable for screening large number of samples. One set of IDDM patient (n=10) and control (n=50) standard sera were used to develop quantitative antibody assays with in vitro synthesized recombinant 35S-methionine-labelled GAD65 and GAD67, respectively, and protein A-Sepharose to separate free from antibody-bound ligand. Binding levels were not normally distributed (p<0.0001) and therefore, the diagnostic accuracy of GAD antibodies was analysed by the ROC plots in population-based, consecutively-diagnosed, recent onset, 0-14 year-old patients (n=105), and matched, healthy control subjects (n=157). The ROC plots showed that the diagnostic sensitivity of GAD65 antibodies was 77% and the specificity 92% compared with 8% and 98%, respectively for GAD67 antibodies. In the IDDM sera, GAD65 and GAD67 antibodies were concordant in 7% (6 of 81) and GAD65 antibodies and ICA in 89% (72 of 81) without a correlation between the autoantibody levels. Autoantibodies to recombinant human islet GAD65 are specific and sensitive markers for childhood IDDM in this immunoassay with in vitro synthesized 35S-methioninelabelled recombinant GAD.
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| 5. |
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| 6. |
- Navara, E., et al.
(författare)
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Investigation of microstructural changes occurring during warm working of manganese partitioned dual phase steel
- 1990
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Ingår i: Materials Science and Technology. - : Informa UK Limited. - 0267-0836 .- 1743-2847. ; 6:2, s. 151-155
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents results from studies using transmission and high resolution electron microscopy of as-received and warm worked manganese partitioned dual phase steel. A growing manganese enriched austenite grain shares two different boundaries with ferrite: (a) a stationary coherent boundary, replacing a stretch of the original ferrite/ferrite boundary, and (b) a migrating non-coherent boundary. This finding gives support to a previously described mechanism of the nucleation and growth of the manganese enriched austenite. The structure of the warm worked steel consists of recovered ferrite strengthened by substructure, and fine martensitic lathes separated by low angle boundaries which resulted from the transformation of deformed non-recrystallised austenite grains
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