University of Bath

About: University of Bath is a education organization based out in Bath, Bath and North East Somerset, United Kingdom. It is known for research contribution in the topics: Population & Photonic-crystal fiber. The organization has 15830 authors who have published 39608 publications receiving 1358769 citations. The organization is also known as: Bath University.

Do Consumers Care About Ethical-Luxury?

Abstract: This article explores the extent to which consumers consider ethics in luxury goods consumption. In particular, it explores whether there is a significant difference between consumers’ propensity to consider ethics in luxury versus commodity purchase and whether consumers are ready to purchase ethical-luxury. Prior research in ethical consumption focuses on low value, commoditized product categories such as food, cosmetics and high street apparel. It is debatable if consumers follow similar ethical consumption patterns in luxury purchases. Findings indicate that consumers’ propensity to consider ethics is significantly lower in luxury purchases when compared to commoditized purchases and explores some of the potential reasons for this reduced propensity to identify or act upon ethical issues in luxury consumption.

The effect of chemical treatment on the properties of hemp, sisal, jute and kapok for composite reinforcement

Abstract: Two chemical treatments were applied to hemp, sisal, jute and kapok natural fibres to create better fibre to resin bonding in natural composite materials. The natural fibres have been treated with varying concentrations of caustic soda with the objective of removing surface impurities and developing fine structure modifications in the process of alkalisation. The same fibres were also acetylated with and without an acid catalyst to graft acetyl groups onto the cellulose structure, in order to reduce the hydrophilic tendency of the fibres and enhance weather resistance. Four characterisation techniques, namely XRD, DSC, FT-IR and SEM, were used to elucidate the effect of the chemical treatment on the fibres. After treatment the surface topography of hemp, sisal and jute fibres is clean and rough. The surface of kapok fibres is apparently not affected by the chemical treatments. X-ray diffraction shows a slight initial improvement in the crystallinity index of the fibres at low sodium hydroxide concentration. However, high caustic soda concentrations lower the fibre crystallinity index. Thermal analysis of the fibres also indicates reductions in crystallinity index with increased caustic soda concentrations and that grafting of the acetyl groups is optimised at elevated temperatures. Alkalisation and acetylation have successfully modified the structure of natural fibres and these modifications will most likely improved the performance of natural fibre composites by promoting better fibre to resin bonding. Naturfasern aus Hanf, Sisal, Jute und Kapok wurden mit zwei chemischen Methoden behandelt, um eine bessere Faser-Matrix-Anbindung in naturfaserverstarkten Verbundmaterialien zu erreichen. Die Fasern wurden mit Natronlauge verschiedener Konzentration behandelt, um Oberflachenverunreinigungen zu entfernen und die Faserfeinstruktur zu modifizieren. Diese Fasern wurden dann mit und ohne sauren Katalysator acetyliert, um die Hydrophilie der Fasern zu reduzieren und deren Witterungsbestandigkeit zu verbessern. Die Auswirkung der chemischen Modifizierung wurde mit XRD, DSC, FT-IR und SEM untersucht. Nach der Behandlung ist die Oberflachentopographie der Hanf-, Sisal- und Jutefasern sauber und rauh. Die Oberflache der Kapokfasern blieb offensichtlich unverandert. Rontgenbeugungsmessungen zeigen einen leicht erhohten Kristallinitatsindex der mit niedrigen NaOH-Konzentrationen behandelten Fasern. Hohe NaOH-Konzentrationen erniedrigen jedoch den Kristallinitatsindex. Die thermische Analyse der Fasern weist ebenfalls auf eine Erniedrigung des Kristallinitatsindexes mit zunehmender NaOH-Konzentrationen hin und das die Acetylierung bei hoheren Temperaturen leichter ablauft. Mit der Alkalisierung und Acetylierung konnte die Struktur der Naturfasern erfolgreich modifiziert werden, was deren Leistungsvermogen durch verbesserte Faser-Harz-Bindung erhohen durfte.

The Crystal Structure of Citrate Synthase from the Hyperthermophilic Archaeon Pyrococcus furiosus at 1.9 Å Resolution

Abstract: The crystal structure of the closed form of citrate synthase, with citrate and CoA bound, from the hyperthermophilic Archaeon Pyrococcus furiosus has been determined to 1.9 A. This has allowed direct structural comparisons between the same enzyme from organisms growing optimally at 37 degrees C (pig), 55 degrees C (Thermoplasma acidophilum) and now 100 degrees C (Pyrococcus furiosus). The three enzymes are homodimers and share a similar overall fold, with the dimer interface comprising primarily an eight alpha-helical sandwich of four antiparallel pairs of helices. The active sites show similar modes of substrate binding; moreover, the structural equivalence of the amino acid residues implicated in catalysis implies that the mechanism proceeds via the same acid-base catalytic process. Given the overall structural and mechanistic similarities, it has been possible to make detailed structural comparisons between the three citrate synthases, and a number of differences can be identified in passing from the mesophilic to thermophilic to hyperthermophilic citrate synthases. The most significant of these are an increased compactness of the enzyme, a more intimate association of the subunits, an increase in intersubunit ion pairs, and a reduction in thermolabile residues. Compactness is achieved by the shortening of a number of loops, an increase in the number of atoms buried from solvent, an optimized packing of side chains in the interior, and an absence of cavities. The intimate subunit association in the dimeric P. furiosus enzyme is achieved by greater complementarity of the monomers and by the C-terminal region of each monomer folding over the surface of the other monomer, in contrast to the pig enzyme where the C-terminus has a very different fold. The increased number of intersubunit ion pairs is accompanied by an increase in the number involved in networks. Interestingly, all loop regions in the P. furiosus enzyme either are shorter or contain additional ion pairs compared with the pig enzyme. The possible relevance of these structural features to enzyme hyperthermostability is discussed.