Age-strain interrelations in lipid metabolism of rats

Various aspects of lipid metabolism were compared in Fisher 344 (F) and Sprague-Dawley (SD) rats aged 2, 6, 12, 18 and 24 months. The analyses included free and total cholesterol of serum and liver, LCAT, hepatic HMG-CoA reductase, cholesterol 7α-hydroxylase, fatty acid synthetase, acetyl CoA carboxylase and cholesterol synthesis from acetate or mevalonate. The body weight of SD rats increases with age whereas that of F rats plateaus at 9–12 months. Liver and aorta cholesterol levels were comparable for the 2 strains. Serum cholesterol varied but was usually lower in F rats. HMG-CoA reductase and cholesterol 7α-hydroxylase activities were not significantly different. Cholesterol synthesis from acetate was significantly higher only in 2-month-old F rats; synthesis from mevalonate was similar at each level. Acetyl CoA carboxylase and fatty acid synthetase activity were generally higher in F rats at every age level. The major difference between F and SD rats is in their pattern of weight gain with age. Differences in lipid metabolism are most marked between the young (2-month) rats.     

Stereoisomeric flavour compounds LXXVI: direct enantioseparation, structure elucidation and structure-function relationship of 4-tert-butyl-α-methyldihydrocinnamaldehyde

 Using enantioselective gas chromatography and heptakis(2,3-di-O-acetyl-6-O-tert-butyldimethylsilyl)-β-cyclodextrin (DIAC-TBDMS-β-CD) as the chiral stationary phase, the direct enantioseparation of 4-tert-butyl-α-methyldihydrocinnamaldehyde was achieved. The threshold values and odour characteristics of the enantiomers were investigated by enantioselective gas chromatography/olfactometry. In order to elucidate stereochemical features, the carbonyl-function was oxidized to the corresponding acid and diastereomeric amides were generated with (S)-2-amino-2-phenyl-ethanol [L(+)-α-phenylglycinol] as the enantiopure reagent. After separation and isolation by high-performance liquid chromatography, absolute configurations were deduced from X-ray structure elucidation of a pure stereoisomer. Amide cleavage, reduction and selective oxidation yielded the enantiomers of 4-tert-butyl-α-methyldihydrocinnamaldehyde. Received: 7 October 1996 / Revised version: 18 November 1996     

A new approach to product set selection and segmentation in preference mapping

A common problem in food product development is to identify the consumers’ drivers of liking and to understand in what way they relate to the acceptance data. Usually, one will also be interested in identifying segments of consumers. The main objective of this study was to investigate the use of fuzzy clustering within the area of preference mapping when different consumer groups test different sets of products. A case study on low-fat cheese was used to explore and illustrate the proposed approach. Two groups of 57 and 58 consumers, respectively, participated in the consumer test. Based on sensory profiling, different cheese products evenly distributed in the sensory space were selected for each group. Each consumer rated their acceptance based on a blind tasting of six cheeses. One of the segments was identified to have a linear preference pattern, while the other two had non-linear patterns.     

Acceptance of calorie-reduced yoghurt: Effects of sensory characteristics and product information

The main objective of this paper was to study acceptance of yoghurt with different levels of two specific sensory attributes, sweetness and richness, when corresponding information about sugar and fat content was given simultaneously with tasting. A conjoint design was applied to examine the effects of intrinsic attributes (sensory) and extrinsic attributes (health information) on acceptability and purchase probability for calorie-reduced vanilla yoghurt. Based on sensory profiling of 12 yoghurts produced according to an experimental design, four yoghurts varying in sweetness and richness were selected. In the conjoint study this sensory variation was combined with information concerning fat content and sugar content. 153 health conscious consumers participated in a blind testing and a conjoint study. Analyses of variance showed that sweetness and information about sugar content had significant effects on liking and purchase probability. The study showed that conjoint methodology was an appropriate tool to reveal effects of extrinsic and intrinsic product attributes.     

Applied Mineralogy of Pyrometallurgical Products

The application of mineralogical techniques to the study of pyrometallurgical products can provide important information that allows a better understanding of the reactions that occur within the furnace. The reactions can be deduced from the reflected light determinations of variations in mineralogical assemblages between, samples collected from different portions of the furnace and by the direct observations under reflected light of mineral textures in which one mineral is partly reacted to another. Compositional variations within mineral solid solutions can be quantitatively determined by electron microprobe analyses. Phase abundances within each sample can be quantitatively determined by automatic image analysis. By these techniques, small but important variations in mineral assemblages, phase abundances, phase compositions, and mineral textures can be distinguished between pyrometallurgical samples and related to differences in conditions of production.     

Key Role of Choline Head Groups in Large Unilamellar Phospholipid Vesicles for the Interaction with and Rupture by Silica Nanoparticles

For highly abundant silica nanomaterials, detrimental effects on proteins and phospholipids are postulated as critical molecular initiating events that involve hydrogen-bonding, hydrophobic, and/or hydrophilic interactions. Here, large unilamellar vesicles with various well-defined phospholipid compositions are used as biomimetic models to recapitulate membranolysis, a process known to be induced by silica nanoparticles in human cells. Differential analysis of the dominant phospholipids determined in membranes of alveolar lung epithelial cells demonstrates that the quaternary ammonium head groups of phosphatidylcholine and sphingomyelin play a critical and dose-dependent role in vesicle binding and rupture by amorphous colloidal silica nanoparticles. Surface modification by either protein adsorption or by covalent coupling of carboxyl groups suppresses the disintegration of these lipid vesicles, as well as membranolysis in human A549 lung epithelial cells by the silica nanoparticles. Furthermore, molecular modeling suggests a preferential affinity of silanol groups for choline head groups, which is also modulated by the pH value. Biomimetic lipid vesicles can thus be used to better understand specific phospholipid–nanoparticle interactions at the molecular level to support the rational design of safe advanced materials.     

Parallelizing the Data Cube

This paper presents a general methodology for the efficient parallelization of existing data cube construction algorithms. We describe two different partitioning strategies, one for top-down and one for bottom-up cube algorithms. Both partitioning strategies assign subcubes to individual processors in such a way that the loads assigned to the processors are balanced. Our methods reduce inter processor communication overhead by partitioning the load in advance instead of computing each individual group-by in parallel. Our partitioning strategies create a small number of coarse tasks. This allows for sharing of prefixes and sort orders between different group-by computations. Our methods enable code reuse by permitting the use of existing sequential (external memory) data cube algorithms for the subcube computations on each processor. This supports the transfer of optimized sequential data cube code to a parallel setting.The bottom-up partitioning strategy balances the number of single attribute external memory sorts made by each processor. The top-down strategy partitions a weighted tree in which weights reflect algorithm specific cost measures like estimated group-by sizes. Both partitioning approaches can be implemented on any shared disk type parallel machine composed of p processors connected via an interconnection fabric and with access to a shared parallel disk array.We have implemented our parallel top-down data cube construction method in C++ with the MPI message passing library for communication and the LEDA library for the required graph algorithms. We tested our code on an eight processor cluster, using a variety of different data sets with a range of sizes, dimensions, density, and skew. Comparison tests were performed on a SunFire 6800. The tests show that our partitioning strategies generate a close to optimal load balance between processors. The actual run times observed show an optimal speedup of p.     

Exploring the Role of Management Accounting Systems in Strategic Sensemaking

Abstract

Management accounting systems (MAS) provide an information context that is required for strategic sensemaking. Research from the interpretive perspective of information processing suggests some mechanisms how MAS can contribute to strategic sensemaking, although it neglects the relationship between MAS use and MAS dimensions. The systems-structural perspective identified some important MAS dimensions, but it does not explain how these dimensions contribute to strategic sensemaking. The objective of this study is to explore the role of MAS in sensemaking and how MAS dimensions contribute to this role. Based on 30 interviews with top and middle managers from 7 large companies we suggest a set of MAS dimensions that relates to sensemaking.