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- Berthold, F, et al.
(författare)
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Dissolution of softwood kraft pulps by direct derivatization in lithium chloride/N,N-dimethylacetamide
- 2004
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Ingår i: Journal of Applied Polymer Science. - : Wiley. - 0021-8995 .- 1097-4628. ; 94:2, s. 424-431
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Tidskriftsartikel (refereegranskat)abstract
- A method for the characterization of the molar mass distributions (MMDs) of softwood kraft pulps dissolved in 0.5% lithium chloride (LiCl)/N,N-dimethylacetamide (DMAc) by size exclusion chromatography is presented. The method is based on derivatization with ethyl isocyanate and the dissolution of samples in 8% LiCl/DMAc. In this study, the derivatization of hardwood kraft pulps did not influence the MMD. In the case of softwood pulps, however, the derivatization decreased the proportion of the high-molecular-mass material and increased the proportion of the low-molecular-mass material, which resulted in a distribution similar to the MMD of a hardwood kraft pulp. The results suggest that associations between hemicellulose and cellulose in the softwood kraft pulp were ruptured during derivatization. This led to a more correct estimation of the MMD of derivatized softwood kraft pulps than obtained by the dissolution of nonderivatized samples. This new method offers several advantages over derivatization with phenyl isocyanate: a precipitation step is not necessary, it is possible to follow the lignin distribution in the samples, and the method allows very high levels of dissolution of softwood kraft pulps up to a kappa number of around 50.
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| 2. |
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| 3. |
- Nystrom, T, et al.
(författare)
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Effects of glucagon-like peptide-1 on endothelial function in type 2 diabetes patients with stable coronary artery disease
- 2004
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Ingår i: American Journal of Physiology: Endocrinology and Metabolism. - : American Physiological Society. - 1522-1555 .- 0193-1849. ; 287:6, s. 1209-1215
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Tidskriftsartikel (refereegranskat)abstract
- GLP-1 stimulates insulin secretion, suppresses glucagon secretion, delays gastric emptying, and inhibits small bowel motility, all actions contributing to the anti-diabetogenic peptide effect. Endothelial dysfunction is strongly associated with insulin resistance and type 2 diabetes mellitus and may cause the angiopathy typifying this debilitating disease. Therefore, interventions affecting both endothelial dysfunction and insulin resistance may prove useful in improving survival in type 2 diabetes patients. We investigated GLP-1's effect on endothelial function and insulin sensitivity (S-I) in two groups: 1) 12 type 2 diabetes patients with stable coronary artery disease and 2) 10 healthy subjects with normal endothelial function and S-I. Subjects underwent infusion of recombinant GLP-1 or saline in a random crossover study. Endothelial function was measured by postischemic FMD of brachial artery, using ultrasonography. S-I [in (10(-4) dl.kg(-1).min(-1))/(muU/ml)] was measured by hyperinsulinemic isoglycemic clamp technique. In type 2 diabetic subjects, GLP-1 infusion significantly increased relative changes in brachial artery diameter from baseline FMD(%) (3.1 +/- 0.6 vs. 6.6 +/- 1.0%, P < 0.05), with no significant effects on S-I (4.5 &PLUSMN; 0.8 vs. 5.2 &PLUSMN; 0.9, P = NS). In healthy subjects, GLP-1 infusion affected neither FMD(%) (11.9 &PLUSMN; 0.9 vs. 10.3 &PLUSMN; 1.0%, P = NS) nor S-I (14.8 &PLUSMN; 1.8 vs. 11.6 &PLUSMN; 2.0, P = NS). We conclude that GLP-1 improves endothelial dysfunction but not insulin resistance in type 2 diabetic patients with coronary heart disease. This beneficial vascular effect of GLP-1 adds yet another salutary property of the peptide useful in diabetes treatment.
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