Chemical and physical properties of the interfacial region formed between unreactive aggregate and hydrothermally cured cement

Model cement rock (aggregate) interaction experiments were carried out hydrothermally at temperatures of 200 and 250°C at 51.7 MPa pressure for times up to 21 days. Cylindrical configuration samples of Class J cement with a sandstone and a limestone exhibited shear bond strengths approximately equivalent to the tensile strength of the reacted cement itself. Electron microprobe traverses perpendicular to the interface revealed apparent compositional irregularities, both experimental and consequent upon physical irregularities in the rock cylinders. Minimal reaction was apparent under these conditions between the hydrothermal cement and the rocks.     

The site of airway irritation during induction of anaesthesia

The aim of this investigation was to study the role of the nasal airway in mediating upper airway reflexes during induction of anaesthesia when the commonly used irritant inhalational anaesthetic agent enflurane is used. In a prospective randomised study, 40 ASA 1 & 2 day-case patients undergoing body surface surgery were recruited. Following intravenous induction using propofol, 20 patients received enflurane administered via a laryngeal mask airway (LMA), the anaesthetic vapour therefore bypassing the nasal airway. In the other group, 20 patients received enflurane anaesthesia administered using a face mask, the nasal airway therefore being exposed to inhalation anaesthetic. We were unable to demonstrate any significant (p < 0.05) differences between the two groups in relation to upper airway complications (cough, breath holding, laryngeal spasm, bronchospasm and excitement). Previous work has identified the nose as a possible important reflexogenic site for upper airway reflexes in humans during anaesthesia. We have been unable to demonstrate any difference in upper airway complications when the nasal airway was included or excluded from exposure to irritant anaesthetic vapours, when administered in a clinical setting.     

Lipolysis and Oxidation in Ultra‐High Temperature Milk Depend on Sampling Month,Storage Duration,and Temperature

During storage, some factors (for example, storage duration and temperature) can affect milk stability and consumer acceptability. Thiobarbituric acid reactive substances (TBARSs), lipid classes, and fatty acid profiles in stored ultra‐high temperature (UHT) milk were analyzed to assess the effects of storage time and temperature on lipid oxidation and lipolysis. With storage duration up to 12 months, the milk fat phase was separated and showed high levels of oxidation and lipolysis, manifested as increased levels of TBARS and free fatty acids. High oxidation levels decreased the percentage of unsaturated fatty acids (UFAs) in triacylglycerol and phospholipids. Higher storage temperatures (20, 30, and 37 °C) resulted in a higher degree of fat aggregation, oxidation, and lipolysis compared with refrigerated storage (4 °C). Additionally, sampling month of raw milk (May, July, and November) affected the lipid profiles of UHT milk during storage, with more UFA oxidized in July than in the other 2 months.     

Structure-fracture measurements of particulate gels

Images on a micron scale and the stress-strain behaviour of gel structures during tension were simultaneously recorded in real time using a mini fracture cell under the confocal laser scanning microscope (CLSM). -lactoglobulin gels tailor-made to vary in density, connectivity, thickness of strands and size of aggregates and clusters were used as a food model system. Amylopectin and gelatin were used to generate different types of -lactoglobulin network microstructures and also as a second continuous phase.Both rheological and structural differences in fragility between -lactoglobulin gels were verified according to the density of their aggregated network structure. A dense gel has a more brittle behaviour where the clusters are rigid and the crack propagates smoothly compared to a gel with an open network structure, which has a discontinuous crack growth, via a winding pathway around clusters, and also break-up of the pores far from the crack tip. Differences in the stretchability of the aggregated -lactoglobulin structure, induced by addition of amylopectin solution, were proved and related to differences in stress-strain behaviour and crack propagation.Gelatin gels in the pores between the -lactoglobulin clusters do not affect the structure of the -lactoglobulin network but make the fracture fragile giving a smooth fracture surface, cause continuous crack growth and fracture propagation through -lactoglobulin clusters. This is a consequence of that the mixed gel follows the behaviour of the gelatin gel when the gelatin phase is stronger than the -lactoglobulin network.