Converting three-space matrices to equivalent six-space matrices for Delone scalars in S6.

The transformations from the primitive cells of the centered Bravais lattices to the corresponding centered cells have conventionally been listed as three-by-three matrices that transform three-space lattice vectors. Using those three-by-three matrices when working in the six-dimensional space of lattices represented as Selling scalars as used in Delone (Delaunay) reduction, one could transform to the three-space representation, apply the three-by-three matrices and then back-transform to the six-space representation, but it is much simpler to have the equivalent six-by-six matrices and apply them directly. The general form of the transformation from the three-space matrix to the corresponding matrix operating on Selling scalars (expressed in space S6) is derived, and the particular S6matrices for the centered Delone types are listed. (Note: in his later publications, Boris Delaunay used the Russian version of his surname, Delone.)

Effects of ursodeoxycholic acid on synthesis of cholesterol and bile acids in healthy subjects

Background/Aims: Ursodeoxycholic acid ( UDCA) decreases biliary secretion of cholesterol and is therefore used for the dissolution of cholesterol gallstones. It remains unclear whether these changes in biliary cholesterol excretion are associated with changes in cholesterol synthesis and bile acid synthesis. We therefore studied the activities of rate-limiting enzymes of cholesterol synthesis and bile acid synthesis, 3-hydroxy-3-methyl-glutarylcoenzyme A reductase and cholesterol 7alpha-hydroxylase, respectively, in normal subjects during UDCA feeding. Methods: UDCA was given to 8 healthy volunteers ( 5 men, 3 women; age 24-44 years) in a single dose of 10-15 mg/kg body weight for 40 days. Before and during ( days 3, 5, 10, 20, 30 and 40) UDCA treatment, urinary excretion of mevalonic acid and serum concentrations of 7alpha-hydroxy-4-cholesten-3-one (7alpha-HCO) were determined as markers of cholesterol and bile acid synthesis, respectively. The Wilcoxon signed rank test and Spearman's rank correlation coefficient were used for statistical analysis. Results: Cholesterol synthesis and serum lipid concentrations remained unchanged during UDCA treatment for 40 days. However, synthesis of bile acids increased during long-term treatment with UDCA as reflected by an increase in 7alpha-HCO serum concentrations from 39.7 +/- 21.3 ng/ml (median 32.8 ng/ml) before treatment to 64.0 +/- 30.4 ng/ml (median 77.5 ng/ml) at days 30-40 of UDCA treatment ( p < 0.05). Conclusions: UDCA treatment does not affect cholesterol synthesis in the liver, but does increase bile acid synthesis after prolonged treatment. This may represent a compensatory change following decreased absorption of endogenous bile acids as observed with UDCA therapy

Engaging Undergraduates in Special Collections Through English Composition

In an atmosphere of increasingly homogeneous general collections, it has been said that special collections holdings will be what sets academic libraries apart from one another. Because of this shift, it is becoming increasingly important for librarians to demystify these collections and actively engage undergraduates in their use. Perhaps one of the most effective strategies to accomplish this feat is collaborate with campus faculty to develop assignments that require students to utilize special collections materials

Genetic engineering, breeding and biodiversity. Summary

Will the use of genetic breeding techniques finally destroy the remaining agricultural diversity of varieties, or can modern biotechnology actually help in the conservation and use of global biodiversity? What strategies are being discussed for the long-term protection of biodiversity, what role can international agreements play in this? And what political possibilities or necessities for action result from this? These are the guiding questions of this study commissioned by the German Bundestag. On the basis of an overview of the situation of biological diversity in Germany and worldwide, as well as of the status and perspectives of plant breeding, the authors describe chains of effects that can emanate from the use of new plant varieties in agriculture. In particular, they ask whether the use of genetic engineering methods will exert qualitatively new influences compared to conventional breeding approaches. Based on this technology-centred perspective, the need for action with regard to the conservation of agricultural diversity as a whole is discussed, with concepts of comprehensive coordination and integration at the spatial, content-related, institutional and political levels forming the core of the proposals