The time required for recovery from mixing stress in young bulls and the prevention of dark cutting beef

Two trials were conducted in which a total of twenty-eight Friesian bulls (12 months old) were slaughtered 0, 1, 2, 4, 7, 9 or 10 days after they had been mixed with unfamiliar animals overnight. The resulting behavioural interactions and associated physical activity led to large rises in plasma creatine phosphokinase (CPK) activity and free fatty acid (FFA) concentration and a decrease in plasma lactate. In the second trial the relative number of interactions engaged in by each animal was estimated. Bulls which exhibited the most interactions had the highest levels of plasma CPK and FFA after mixing. Liver and muscle glycogen were depleted by mixing. Animals killed on days 0 and 1 after mixing had low concentrations of liver glycogen compared with animals allowed longer to recover. Concentrations of glycogen in the M. longissimus dorsi (LD) had recovered by day 4 and in the M. psoas by day 2. Muscle glycogen concentrations were reflected in the ultimate pH (pHu) of the meat. All animals killed immediately after mixing produced carcasses with pHu>6. in the LD. By the second day of recovery muscle glycogen stores had been repleted sufficiently so that all animals had muscles with pHu<6. However, the LD from these animals was still very slightly darker than those killed after 7 or more days of recovery although this was probably not commercially significant. It was concluded that, if young bulls from separate rearing groups are mixed before slaughter, either on the farm or during lairage, then they require resting with food for at least 48 h before being killed to ensure that no carcasses are produced with high pHu in the musculature.     

Conceptualising improvisation in information systems security

Information Systems Security (ISS) has constantly been ranked as a key concern for Information Systems (IS) managers. Research in the field has largely assumed rational choice (functional) approaches to managing ISS. Such approaches do not give due recognition to the role of improvisation in ISS work. Empirical evidence in organisations suggests that in the context of dynamic, volatile and uncertain environments practitioners are both rational and adaptive (a manifestation of improvisation). In this paper, we conceptualise and demonstrate the manifestation of improvisation in ISS. In order to develop a better understanding of improvisation in ISS activities, hermeneutical and exegetical techniques were employed. Empirical data were collected through in-depth interviews in a single case study. The data obtained were analysed and interpreted hermeneutically. Generally it was found that improvisation is manifested in ISS activities. Implications of these and other findings for the scholarly community and for practical use are discussed.     

A model for brittle-ductile transitions in polymers

A model is proposed for mixed-mode crack propagation in materials which show shear lips on the fracture surface. The model is shown to predict the existance of a brittle-ductile transition as the specimen thickness is decreased. The predictions of the model are compared with published experimental data on a number of polymers including polycarbonate, and good agreement is found.     

Monitoring the Synthesis and Composition Analysis of Microsilica Encapsulated Acetylacetonatocarbonyl TriphenylphosphinerhodiumCatalyst by Inductively Coupled Plasma (ICP) Techniques

A novel technique to monitor the synthesis process of encapsulated acetylacetonatocarbonyl triphenylphosphinerhodium within a microsilica nanoshell has been studied using inductively coupled plasma (ICP) techniques. Nanospheres sized around 50-100 nm were obtained and ICP was used to quantify the exact composition of rhodium, phosphorous, and silicon with differing digestion solvents. In addition, ICP was used to detect rhodium and phosphorous in the nano core-shell catalysts as a quality control procedure     

Core-referenced ratiometric fluorescent potassium ion sensors using self-assembled ultrathin films on europium nanoparticles

Nanoengineered fluorescent sensor coatings on colloidal carriers have been developed for use intracellularly. These nanosensors are fabricated via the electrostatic layer-by-layer self-assembly technique to form ultrathin polyelectrolyte films containing indicators on fluorescent nanoparticles. The fluorescent nanoparticle templates and the fluorescent indicator are chosen such that their optical properties are complementary, enabling the inert nanoparticle templates to serve as internal intensity references for the fluorescent probe. In this work, the potassium ion indicator, potassium-binding benzofuran isophthalate potassium-binding benzofuran isophthalate was immobilized within poly(styrene sulfonate)/poly(allylamine hydrochloride) films assembled on the surface of fluorescent europium nanoparticles. The indicator retains its sensitivity to potassium ions after immobilization within the films and exhibits sensitivity to increases in potassium concentration over a broad range. In addition, the sensors demonstrate excellent leaching stability, with less than 1% of loaded indicator leached after 14 days of wet storage. The core-referenced nanosensor scheme described here is a simple and elegant way to co-immobilize fluorescent indicator and intensity reference within a single nanoscale package, which may be deployed intracellularly; furthermore, the separation of fluorescent indicator from the cellular environment is attractive, as it may prevent complications due to use of liquid-phase fluorescent sensors intracellularly, such as cytotoxicity and probe compartmentalization.     

A low-cost,high-performance pulse generator for ultrasound imaging

The design of a low-cost pulse generator for ultrasound imaging is presented. The pulser can provide 10 kW pulses with less than 0.7 Vpp ringing. Pulses ranging from 10 to 500 ns have been successfully generated