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We illustrate the use of intersection types as a semantic tool for showing properties of the lattice of lambda theories. Relying on the notion of easy intersection type theory we successfully build a filter model in which the interpretation of an arbitrary simple easy term is any filter which can be described in an uniform way by a predicate. This allows us to prove the consistency of a well-know lambda theory: this consistency has interesting consequences on the algebraic structure of the lattice of lambda theories.

Contains fulltext : mmubn000001_232205140.pdf (Publisher’s version ) (Open Access) Promotor : H. Barendregt IV, 148 p.

The effects of the type 1 angiotensin II receptor antagonist Losartan potassium on intraocular pressure (IOP) were studied. Four groups of subjects were analysed: group A, ten controls; group B, ten patients with essential arterial hypertension and with IOP within the normal range; group C, ten patients with primary open angle glaucoma (POAG), but without essential arterial hypertension; group D, ten patients with arterial hypertension and POAG. The study design was held in a randomized crossover double-blind fashion. Systolic and diastolic arterial pressure, heart rate, pupil diameter, IOP and total outflow facility were recorded at baseline and at 1 hr intervals up to 6 hr, following the oral administration of 50 mg of Losartan potassium and/or placebo. The alternative treatment was given a week later. Drug administration significantly reduced IOP in all subjects. No variation in heart rate and pupil diameter was observed during the follow-up period. Blood pressure dropped only in arterial hypertensive patients (groups B and D). Total outflow facility increased significantly in all groups. Placebo did not induce any variation in all groups. These findings demonstrate that the mechanism by which Losartan potassium reduces intraocular pressure is not mediated by a decrease in blood pressure, but rather it is more specific, confirming the role of the renin-angiotensin system also in the regulation of intraocular pressure in man.

In network applications it is crucial to have a mechanism to guarantee that communications evolve correctly according to the agreed protocol. Session types offer a method for abstracting and validating structured communication sequences (sessions). In this paper we propose union types for refining and enhancing the flexibility of session types in the context of communication centred and object oriented programming. We demonstrate our ideas through an example and a calculus formalising the main issues of the present approach. The type system garantees that, in well-typed executable programs, after a session has started, the values sent and received will be of the appropriate type, and no process can get stuck forever.

Earlier work explored the introduction of session types into object oriented languages. Following the session types literature, two parties would start communicating, provided the types attached to that communication, i.e. the corresponding session types, were dual of each other. Then, the type system was able to ensure soundness, in the sense that two communicating partners were guaranteed to receive/send sequences of values following the order specified by their session types. In the current paper we improve upon our earlier work in two ways: we extend the type system to support bounded polymorphism, and we make the selection more object-oriented, so that control structures determine how to continue evaluation, depending on the class of the object being sent/received. Interestingly, although our notion of selection is more powerful than that in earlier work, the ensuing system turned out not to be more complex, except for the notion of duality, which needed to be extended, to correctly deal with bounded polymorphism, and to capture the new notion of selection. The paper contains an example, informal explanations, a formal description of the operational semantics and of type system, and a proof of subject reduction.

Purpose: In this investigation the authors studied the effect of dapiprazole, an alpha-adrenergic blocking agent, on aqueous humor dynamics in patients affected with pigmentary glaucoma. Methods: Dapiprazole 0.5% eye drops were administered 3 times daily as adjunctive therapy to 16 pigmentary glaucoma patients in addition to timolol 0.5% eye drops twice daily. Computerized tonography was performed before and 3, 12 and 36 months after dapiprazole treatment. Sixteen sex- and age-matched pigmentary glaucoma patients treated with timolol 0.5% eye drops alone were used as a control group. Results: After 36 months of follow-up, the dapiprazole-treated group showed a significant increase in total outflow facility (C, from 0.17 ± 0.04 to 0.22 ± 0.07 ml min-1 mm Hg-1; p = 0.010, paired t test) and Po/C ratio (Q) significantly decreased from 113.39 ± 31.02 to 89.22 ± 51.66 (p = 0.036, paired t test). Conclusions: Our results show that the introduction of dapiprazole in the therapy of pigmentary glaucoma may be useful in the long-term management of these patients. Its mechanism of action is likely to be due to iridoplegia; in fact, a decrease in the shedding of pigment occurs and, with time, the outflow facility increases and the pigment clearance from the trabecular meshwork is enhanced.

The objective of this study was to test bacteria ability to use Na-hyaluronate as a nutrient in vitro. Thirteen bacteria strains were tested in three different media: specific culture medium, agar-Healon medium and agar-Healon GV medium. The bacterial growth criteria were determined by counting the number of new colonies appearing at each observation time (0, 24, 48 and 72 h). The results were expressed as the percentage of growth in agar-Na-hyaluronate compared to each corresponding specific culture medium. After 24 h in the medium containing agar-Healon, S. aureus, S. epidermidis, S. pyogenes and S. viridans grew using hyaluronic acid as a nutrient. The percentage of growth of these species remained constant over the follow-up period. The other bacteria strains tested were unable to use Healon as a nutrient. After 24 h of incubation in the medium containing agar-Healon GV, S. aureus, S. epidermidis, S. pyogenes, and S. viridans exhibited about 20% growth. Subsequently, this percentage slowly increased to about 50%. The other bacteria stains tested were unable to employ Healon GV as a nutrient. With the exception of Staphylococci and Streptococci, the other species do not synthesize the necessary enzymes to break glucosidic bonds, therefore neither concentration of hyaluronic acid can be utilized as a source of carbohydrate for their survival in culture media.