Five years of peripheral percutaneous transluminal angioplasty : the St Luke’s Hospital experience

This article reviews the first series of 54 cases of Percutaneous Transluminal Angioplasty on the peripheral vasculature performed at the Radiological/Surgical Department at St. Luke’s Hospital, Malta, over a five year period. After describing in detail the technique used, the indications and the objective criteria utilised for assessment are reviewed and analysed. The two year patency rate for femoro-popliteal and iliac stenoses was 93% and 86% respectively, while for corresponding occlusions, the figures were 42% and 0% respectively. Thus, while the results were very encouraging for femoro-popliteal stenoses and occlusions, they were unacceptable for iliac occlusions. As expected the major risk factors were smoking, diabetes mellitus and associated ischaemic heart or cerebrovascular disease. This series had no mortality and there was minimal morbidity, mainly at the site of arterial access. Elective surgery for iliac re-stenosis was only required in one patient.peer-reviewe

Management of Glaucoma in the Maltese Health Service

Glaucoma is a disease with characteristic changes of the optic nerve, visual field and raised intra ocular pressure. Its prevalence varies between, 1.6 to 8% and is dependent on the ethnic composition of the population and it is one of the leading causes of blindness in the developed world. There are 67 800 000 people worldwide suffering from glaucoma.1 In recent years, a number of highly potent topical medications have been introduced. These have substantially improved the conservative management of glaucoma. New laser techniques are also being used and safer operative techniques have been developed in order to cope with the more resistant cases of glaucoma. A previous study on `Glaucoma in Malta', conducted in 1989, established that 3% of Maltese population over the age of 40 suffers from glaucoma.2 This study was carried out in order to assess the management of glaucoma patients in the Maltese Government Health Service at the present time.peer-reviewe

Survey of Period Variations of Superhumps in SU UMa-Type Dwarf Novae

We systematically surveyed period variations of superhumps in SU UMa-type dwarf novae based on newly obtained data and past publications. In many systems, the evolution of superhump period are found to be composed of three distinct stages: early evolutionary stage with a longer superhump period, middle stage with systematically varying periods, final stage with a shorter, stable superhump period. During the middle stage, many systems with superhump periods less than 0.08 d show positive period derivatives. Contrary to the earlier claim, we found no clear evidence for variation of period derivatives between superoutburst of the same object. We present an interpretation that the lengthening of the superhump period is a result of outward propagation of the eccentricity wave and is limited by the radius near the tidal truncation. We interpret that late stage superhumps are rejuvenized excitation of 3:1 resonance when the superhumps in the outer disk is effectively quenched. Many of WZ Sge-type dwarf novae showed long-enduring superhumps during the post-superoutburst stage having periods longer than those during the main superoutburst. The period derivatives in WZ Sge-type dwarf novae are found to be strongly correlated with the fractional superhump excess, or consequently, mass ratio. WZ Sge-type dwarf novae with a long-lasting rebrightening or with multiple rebrightenings tend to have smaller period derivatives and are excellent candidate for the systems around or after the period minimum of evolution of cataclysmic variables (abridged).Comment: 239 pages, 225 figures, PASJ accepte

Optimizing oxygen reduction catalyst morphologies from first principles

Catalytic activity of perovskites for oxygen reduction (ORR) was recently correlated with bulk d-electron occupancy of the transition metal. We expand on the resultant model, which successfully reproduces the high activity of LaMnO3 relative to other perovskites, by addressing catalyst surface morphology as an important aspect of the optimal ORR catalyst. The nature of reaction sites on low index surfaces of orthorhombic (Pnma) LaMnO3 is established from First Principles. The adsorption of O2 is markedly influenced by local geometry and strong electron correlation. Only one of the six reactions sites that result from experimentally confirmed symmetry-breaking Jahn?Teller distortions is found to bind O2 with an intermediate binding energy while facilitating the formation of superoxide, an important ORR intermediate in alkaline media. As demonstrated here for LaMnO3, rational design of the catalyst morphology to promote specific active sites is a highly effective optimization strategy for advanced functional ORR catalyst