Transglutaminase mediated grafting of silk proteins onto wool fabrics leading to improved physical and mechanical properties

Transglutaminases have the ability to incorporate primary amines and to graft peptides (containing glutamine or lysine residues) into proteins. These properties enable transglutaminases to be used in the grafting of a range of compounds including peptides and/or proteins onto wool fibres, altering their functionality. In this paper we investigated the transglutaminase mediated grafting of silk proteins into wool and its effect on wool properties. A commercial hydrolysed silk preparation was compared with silk sericin. The silk sericin protein was labelled with a fluorescent probe which was used to demonstrate the efficiency of the TGase grafting of such proteins into wool fibres. The TGase mediated grafting of these proteins led to a significant effect on the properties of wool yarn and fabric, resulting in increased bursting strength, as well as reduced levels of felting shrinkage and improved fabric softness. Also observed was an accumulation of deposits on the surface of the treated wool fibres when monitored by SEM and alterations in the thermal behaviour of the modified fibres, in particular for mTGase/sericin treated fibres which, with the confocal studies, corroborate the physical changes observed on the treated wool fabric. © 2006 Elsevier Inc. All rights reserved.

Transglutaminase treatment of wool fabrics leads to resistance to detergent damage

Biological detergents are now routinely used in domestic laundry because the enzymes they contain provide the added benefit of low temperature washes with improved cleaning performance. One of the key enzymes found in these detergents are proteases, which if exposed to natural protein fibres such as wool or silk can cause irreversible damage, leading to loss of fabric strength, shape and poor colour fastness. Transglutaminases (TGases) are protein cross-linking enzymes capable of adding tensile strength to wool proteins, and as a consequence are capable of remediating the damage caused by previous chemical treatments, and more importantly, by proteases. In this paper we treated dyed wool fabric with TGase and then washed the fabric with biological and non-biological detergents to investigate whether TGases would protect wool garments from damage by the undue use of biological detergents in domestic laundry. We demonstrate using different cycles of detergent washes containing biological and non-biological detergents and different TGase treatments, that wool fabric treated previously with TGase release less dye into the washing liquor and in addition maintain fabric strength at levels greater than the washed controls. As a consequence, wool garments previously treated with TGase are likely to have increased resistance to domestic washing and thus provide increased longevity. © 2005 Elsevier B.V. All rights reserved.

The process of strategic change:a management perspective

This thesis is concerned with the management processes concerned with complex strategic decision in organisations. The research has sought to explore these processes by taking as its focus the reconstruction of decision processes a) on the basis of an historical study of an industry and in particular a major company in that industry; and b) the perception and understanding of strategic decision processes and change by managers involved in companies in that industry. The main body of analysis and theoretical contributions arise from the detailed analysis of extended depth interviews with managers carried out in 1980 and 1983 which trace thirteen years of the strategic development of a firm. In so doing, extensive use is made of verbatim accounts by managers of events and their interpretation of events. This is then compared with data gathered from.similar interviews with managers of two other companies and examined in the light of existing research and theory in the field. The thesis both provides a detailed insight into the processes associated with the identification and resolution of complex strategic issues and also generates a body of theory concerning the mechanisms by which strategic decisions and the processes of strategic change are interwoven with the cultural and political fabric of organisations. The thesis is divided into four parts. The first part deals with the background to the research, provid1ng a fuller summary of the purpose, structure and content of the thesis and a discussion of relevant previous research and the methodology employed herein. The second part mainly provides case studies of the industry and the main company studied. The third part is a detailed presentation and analysis of data. The fourth part is a synthesis of the findings and consolidation of the theoretical interpretation advanced in the thesis.

Petrology of weathered lower lias clays

In weak argillaceous rocks the unweathered strength may be barely sufficient to meet civil engineering reguirements and any reductjon due to weathering will be critical. This study investigates the weathering of the Lower Lias clays with particular reference to their petrography and engineering properties. Investigations revealed the Midland Basin of deposition to contain reasonable thicknesses of clay, relatively uniform in nature with a well developed weathered zone, From the available exposures, the weathering zone of the Blockley Clay pit was selected and sampled for laboratory investigations of; Structure, Mineralogy and Chemistry and Engineering Properties. The nature and orientation of the fissures in the unweathered clay were analysed. A close relationship was found to exist between the major joint set and the ground surface, with stress release due to excavation being almost negligible. Thin sections of the clay, examined for structural data, suggested that there exist layers or areas that have been disturbed as a result of density differences. Shear planes were found in both the unweathered and weathered clay, in the latter case often associated with remoulding of the material. A direct measure of remoulding was obtained from the birefringence ratio. The fabric was examined in closer detail using the scanning electron microscope. Mineralogy, as revealed by X-ray and optical techniques indicated illite as the dominant clay mineral, with kaolinite subsidiary; quartz, calcite, pyrite, chlorite/vermiculite are present as accessory minerals. Weathering changes this relationship, calcite and pyrite being removed early in the process, with illite being degraded. The cementing action of calcite and iron oxides was investigated however, this was shown to be negligible. Quantitative measurements of both fixed (with minerals) and free (oxide coatings) iron were obtained by atomic absorption, with the Fe 3+/ Fe2+ ratio obtained by Mossbauer spectroscopy, Evidence indicates that free iron oxide coatings only become important as a result of weathering with the maximum concentration in the very highly weathered material. Engineering index properties and shear strength values were taken throughout the profile, Relationships between moisture content and strength, liquid limit and iron (Fe) were obtained and a correlation between the weathering zomes and the shear strength/depth curve has been established.

The performance of stabilized and unstabilized minestone in an aqueous environment with emphasis on its erosion resistance

Britain's sea and flood defences are becoming increasingly aged and as a consequence, more fragile and vulnerable. As the government's philosophy on resources shifts against the use of prime quarried and dredged geo-materials, the need to find alternative bulk materials to bolster Britain's prone defences becomes more pressing. One conceivable source for such a material is colliery waste or minestone. Although a plethora of erosion-abrasion studies have been carried out on soils and soil-cements, very little research has been undertaken to determine the resistance of minestone and its cement stabilized form to the effects of water erosion. The thesis reviews the current extent to which soil-cements, minestone and cement stabilized minestone (CSM) have been employed for hydraulic construction projects. A synopsis is also given on the effects of immersion on shales, mudstones and minestone, especially with regard to the phenomena of slaking. A laboratory study was undertaken featuring a selection of minestones from several British coalfields. The stability of minestone and CSM in sea water and distilled water was assessed using slaking tests and immersion monitoring and the bearing on the use of these materials for hydraulic construction is discussed. Following a review of current erosion apparatus, the erosion/abrasion test and rotating cylinder device were chosen and employed to assess the erosion resistance of minestone and CSM. Comparison was made with a sand mix designed to represent a dredged sand, the more traditional, bulk hydraulic construction material. The results of the erosion study suggest that both minestone and CSM were more resistant to erosion and abrasion than equivalently treated sand mixes. The greater resistance of minestone to the agents of erosion and abrasion is attributed to several factors including the size of the particles, a greater degree of cement bonding and the ability of the minestone aggregate to absorb, rather than transmit shock waves produced by impacting abrasive particles. Although minestone is shown to be highly unstable when subjected to cyclic changes in its moisture content, the study suggests that even in an intertidal regime where cyclic immersion does takes place, minestone will retain sufficient moisture within its fabric to prevent slaking from taking place. The slaking study reveals a close relationship between slaking susceptibility and total pore surface area as revealed by porosimetry. The immersion study shows that although the fabric of CSM is rapidly attacked in sea water, a high degree of the disruption is associated with the edges and corners of samples (ie. free surface) while the integrity of the internal fabric remains relatively intact. CSM samples were shown to be resilient when subjected to immersion in distilled water. An overall assessment of minestone and CSM would suggest that with the implementation of judicious selection and appropriate quality control they could be used as alternative materials for flood and sea defences. It is believed, that even in the harsh regime of a marine environment, CSM could be employed for temporary and sacrificial schemes.

The sedimentology and diagenesis of the Pendleside limestone group in the Craven Basin of Northern England. Available in 2 volumes.

This thesis describes the stratigraphy, sedimentology and diagenesis of the Pendleside Limestone (Asbian age), a sequence of limestones, shales and dolostones in the Clitheroe area of N. W. England. Field study of 19 measured sections indicates that it was deposited in a rhythmically subsiding basin (Craven Basin) because of movements on the Mid-Craven Fault which was active in Dinantian times. The sequence is up to 190m thick and consists mostly of distal turbidite deposits which have been reworked at horizons when sediment accumulation built up to the wave base. The original depositional fabric and mineralogy of the Pendleside Limestone Group has been extensively modified by diagenetic processes including cementation, authi­genesis, dolomitization and silicification. These processes have been studied using a wide variety of laboratory techniques. The carbonate cements of the PendIeside Limestone consist predominantly of ferroan calcite and non-ferroan calcite with microdolomite incIusions. The former is probably a stable replacement of original-high-magnesian calcite. Cementation was accompanied by the formation of authigenic albite and quartz. Much of the upper part of the Pendleside Limestone has been extensively dolomitized and chertified. Several distinct zones of dolomitization are found which increase in thickness and intensity towards the top of the Pendleside Limestone Group. The dolostone horizons correspond to coarser-grained lithologies deposited during periods of shallow water sedimentation. The composition of the dolomites changes from ferroan dolomite in the lower part of the Group to non-ferroan dolomite in the upper part. The low strontium and sodium content of the dolostones in association with the other evidence suggests that the dolomitization was brought about in an open system by the mixing of marine and fresh water in phreatic lens which were established at periodic intervals. The dolomitization was closely associated with chertification although this was initiated by the dissolution of siliceous spicules which provided the necessary source of silica.

A solar powered liquid-desiccant cooling system for greenhouses

Liquid desiccant systems are of potential interest as a means of cooling greenhouses to temperatures below those achieved by conventional means. However, only very little work has been done on this technology with previous workers focussing on the cooling of human dwellings using expensive desiccants such as lithium salts. In this study we are designing a system for greenhouse cooling based on magnesium chloride desiccant which is an abundant and non-toxic substance. Magnesium chloride is found in seawater, for example, and is a by-product from solar salt works. We have carried out a detailed experimental study of the relevant properties of magnesium rich solutions. In addition we have constructed a test rig that includes the main components of the cooling system, namely a dehumidifier and solar regenerator. The dehumidifier is a cross-flow device that consists of a structured packing made of corrugated cellulose paper sheets with different flute angles and embedded cooling tubes. The regenerator is of the open type with insulated backing and fabric covering to spread the flow of desiccant solution. Alongside these experiments we are developing a mathematical model in gPROMS® that combines and simulates the heat and mass transfer processes in these components. The model can be applied to various geographical locations. Here we report predictions for Havana (Cuba) and Manila (Philippines), where we find that average wet-bulb temperatures can be lowered by 2.2 and 3°C, respectively, during the month of May.

Business as usual is not an option

It’s just not an option Sustainability literacy should by now be woven into the fabric of our educational culture. Our present ignorance and lack of engagement is nothing short of shameful, says John Blewitt.

Application of transglutaminases in the modification of wool textiles

The use of the protein-crosslinking enzymes transglutaminases (EC 2.3.2.13), as biocatalysts in the processing of wool textiles offers a variety of exciting and realistic possibilities, which include reducing the propensity of wool fabric to shrink and maintaining or increasing fabric strength. Guinea pig liver (GPL) transglutaminase or the microbial transglutaminase isolated from Streptoverticilium mobaraense, when applied to wool either alone or following a protease treatment, resulted in an increase in wool yarn and fabric strength (up to a 25% increase compared to a control). This indicates that transglutaminases can remediate the negative effects of proteolytic treatments in terms of loss in fibre strength. Incubation of samples pretreated with different oxidative and reducing agents with both sources of transglutaminases led to significant increases in tensile strength for all samples tested, suggesting that yarn strength lost following chemical treatments can also be recovered. The two different transglutaminases (TGases) could also impart a significant reduction in fabric shrinkage. The incorporation of primary amine transglutaminase substrates into wool fibres, with a view to altering wool functionality, was demonstrated using the incorporation of the fluorescent primary amine fluorescein cadaverine (FC). Incubation of wool with this fluorescent amine and transglutaminase led to high levels of incorporation into the fibres. The treatment of wool textiles with transglutaminases indicates that a number of novel and radically different finishes for wool textiles can be developed.