Relation Liftings on Preorders and Posets

The category Rel(Set) of sets and relations can be described as a category of spans and as the Kleisli category for the powerset monad. A set-functor can be lifted to a functor on Rel(Set) iff it preserves weak pullbacks. We show that these results extend to the enriched setting, if we replace sets by posets or preorders. Preservation of weak pullbacks becomes preservation of exact lax squares. As an application we present Moss's coalgebraic over posets

The formation of thallium chloride complexes and their extraction into ether

Thallium is one of a large group of elements which can be extracted into ethers from halogen acid solutions. The general lack of knowledge of the extraction process for these salts has given strong impetus to the study of all aspects of it

Team and group work:a student perspective of assessment and management

Group and team work is an integral part of programme delivery at Abertay. It is however the single are which attracts the most negative comment from student feedback surveys, with students highlighting perceived unfairness in the assessment of coursework. A team of students taken from across the university have developed criteria to evaluate examples of team and group work assessments. They have applied their criteria to a range of different models. Their insight will inform improvements in our practice

Evaluation of bioluminescence-based assays of anti-malarial drug activity

Transgenic Plasmodium falciparum expressing luciferase offers an attractive bioluminescence-based assay platform for the investigation of the pharmacological properties of anti-malarial drugs. Here a side-by-side comparison of bioluminescence and fluorescence-based assays, utilizing a luciferase reporter cassette that confers a strong temporal pattern of luciferase expression during the S-phase of intraerythrocytic development, is reported

The Increasing Role of Percutaneous Transluminal Angioplasty in the Primary Management of Critical Limb Ischaemia

AbstractObjective: to review the current role and results of angioplasty in the management of critical limb ischaemia (CLI) in a single institution.Methods: data on 526 patients with 608 ischaemic limbs, treated between January 1994 and December 1999 was collected prospectively and analysed retrospectively. Patients were divided into 3 groups according to the date of presentation: group 1 (1994–95), group 2 (1996–97) and group 3 (1998–99). The groups were comparable in terms of demographics, mode of presentation and level of disease.Results: Revascularisation was attempted in 87%, 81% and 91% for groups 1, 2 and 3 respectively (NS). Primary percutaneous transluminal angioplasty (PTA) rates increased from 44% (1994–95) to 69% (1998–99) (p < 0.001), and surgical revascularisation rates decreased correspondingly (p<0.01). Overall cumulative patient survival and limb salvage rates were 82% and 89% for 1 year and 45% and 87% for 5 years, respectively. No statistically significant difference existed between the three groups regarding patient survival, limb salvage rates and mean hospital stay (19, 12 and 12 days, respectively).Conclusion: PTA is increasingly replacing bypass surgery in the treatment of CLI, without compromising patient survival or limb salvage rates

Investigation of the antibiofilm capacity of peptide-modified stainless steel

Biofilm formation on surfaces is an important research topic in ship tribology and medical implants. In this study, dopamine and two types of synthetic peptides were designed and attached to 304 stainless steel surfaces, aiming to inhibit the formation of biofilms. A combinatory surface modification procedure was applied in which dopamine was used as a coupling agent, allowing a strong binding ability with the two peptides. X-ray photoelectron spectroscopy (XPS), elemental analysis, contact angle measurement and surface roughness test were used to evaluate the efficiency of the peptide modification. An antibiofilm assay against Staphylococcus aureus was conducted to validate the antibiofilm capacity of the peptide-modified stainless steel samples. XPS analysis confirmed that the optimal dopamine concentration was 40 µg ml−1 in the coupling reaction. Element analysis showed that dopamine and the peptides had bound to the steel surfaces. The robustness assay of the modified surface demonstrated that most peptide molecules had bound on the surface of the stainless steel firmly. The contact angle of the modified surfaces was significantly changed. Modified steel samples exhibited improved antibiofilm properties in comparison to untreated and dopamine-only counterpart, with the peptide 1 modification displaying the best antibiofilm effect. The modified surfaces showed antibacterial capacity. The antibiofilm capacity of the modified surfaces was also surface topography sensitive. The steel sample surfaces polished with 600# sandpaper exhibited stronger antibiofilm capacity than those polished with other types of sandpapers after peptide modification. These findings present valuable information for future antifouling material research

Automated Synthesis of Tableau Calculi

This paper presents a method for synthesising sound and complete tableau calculi. Given a specification of the formal semantics of a logic, the method generates a set of tableau inference rules that can then be used to reason within the logic. The method guarantees that the generated rules form a calculus which is sound and constructively complete. If the logic can be shown to admit finite filtration with respect to a well-defined first-order semantics then adding a general blocking mechanism provides a terminating tableau calculus. The process of generating tableau rules can be completely automated and produces, together with the blocking mechanism, an automated procedure for generating tableau decision procedures. For illustration we show the workability of the approach for a description logic with transitive roles and propositional intuitionistic logic.Comment: 32 page

Micromechanical finite element analyses of fire retardant woven fabric composites at elevated temperatures using unit cells at multiple length scales

This paper presents a micromechanical Finite Element (FE) model developed to predict the effective mechanical properties of glass fibre-reinforced (woven fabric) polymer composites with/without fire retardant particulate additives at elevated temperatures. The elevated mechanical properties of glass fibre-reinforced epoxy composites with/without fire retardants were predicted using three unit cells of varying length scales in micromechanical FE analysis. Theoretically predictions of flexural behaviour of these fibre-reinforced polymer composites at elevated temperatures were satisfactorily validated against experimentally measured data. The numerical model developed herein was then used for the prediction of other mechanical properties of fibre-reinforced polymer composites that would have been difficult to collect at elevated temperatures. Micromechanical FE models such as the one contained in this paper are useful to architectural engineers as they can be used to guide the design and qualification of new engineering composites that satisfy stringent Building codes in fire prone engineering applications