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Search Results: 1 - 10 of 9929 matches for " Bezzina Frank "
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The Impact of Microbiological Pollutants on School Indoor Air Quality  [PDF]
Peter Fsadni, Bezzina Frank, Claudia Fsadni, Stephen Montefort
Journal of Geoscience and Environment Protection (GEP) , 2017, DOI: 10.4236/gep.2017.55004
Abstract: Asthma is common in children with allergens and mould influencing the development of the disease. Since children spend most of their time outside their homes within the school environment, school indoor air quality can directly influence their respiratory health. This study aims to identify microbiological contaminants in Maltese schools. The association between contaminants, respiratory health and school characteristics has been analysed. Five primary schools were selected with 9 to 11 years old students participating. Standardised health questionnaires, lung function tests, and school characterisation were performed. Dust samples were analysed for fungi, bacteria and allergens were performed. Penicillium/Aspergillus/Paecilomyces/Variotii (PenAsp) group had the highest median indoor concentration followed by Mycobacterial and Streptomyces species. There was a significant negative correlation between PenAsp and Mycobacterium spp levels in all the participating schools (r = ?0.42; p = 0.03). Cat allergen in classroom dust correlated positively with the number of cat owners (r = 0.43; p = 0.041). High exposure to fungi, bacteria and allergens was significantly associated with upper and lower airway atopy. School/classroom characteristics and cleaning protocols were significantly associated with exposure to these pollutants. In conclusion, fungi, bacteria, endotoxin, cat and dog allergens have been found to have a direct influence on school indoor air quality in the Maltese Islands. A significant association was observed between these contaminants and upper and lower airway atopy. Specific school, classroom, cleaning and maintenance characteristics have been identified as having a direct impact on indoor air quality.
Current Techniques and Practices for Myocardial Stress Testing—A Comparative Survey between Malta and International Nuclear Medicine Centres  [PDF]
Karen Borg Grima, Desiree O’Leary, Paul Bezzina, Louise Rainford
Open Journal of Clinical Diagnostics (OJCD) , 2014, DOI: 10.4236/ojcd.2014.44031
Abstract: Objectives: The study compared cardiac scintigraphy stress scanning practices applied in a National Maltese Nuclear Medicine centre and in international centres. This was achieved through the design of an online survey which investigated participant knowledge of stress testing, and current procedural practice. Methods: An online survey comprising 12 questions was prepared using Survey Monkey. Professional Nuclear Medicine groups such as the Medical-Physics-Engineering community and Virtual Radiopharmacy were targeted. Access to the survey remained open for eight months during which a periodic reminder was sent to optimise the response rate. Forty-three members responded from across Europe and Australasia. Chi-square tests and comparisons between multiple responses using IBM SPSS 20 were used to evaluate the results. Information related to Maltese practice was collated separately for review and comparative purposes. Results: The online survey participants comprised United Kingdom [72%], other European countries [18%] and Australasia [9%]. The majority of respondents [n = 39] reported pharmacological stress testing as being performed either alone or in conjunction with exercise stress testing as the preferred option. Most participants [60%] were aware of local stress test protocols but had limited knowledge in relation to guidelines designed for cases where patients were not suitable for pharmacological stress testing. Conclusion: The survey provided information about procedures within participating centres for scintigraphic cardiac stress scanning. Differences were identified with regards to the preferred radiopharmaceutical tracers and procedural protocols. Further investigation of examination techniques is warranted, with the aim of increasing standardisation of protocol compliance and the application of more suitable practice.
Variabilité de la composition chimique des huiles essentielles de Mentha rotundifolia du Nord de l’Algérie
Moussa Brada,Mohamed Bezzina,Michel Marlier,Annabelle Carlier
Biotechnologie, Agronomie, Société et Environnement , 2007,
Abstract: Variability of the chemical composition of Mentha rotundifolia from Northern Algeria. Algerian oils of Mentha rotundifolia (L.) Huds., obtained by steam distillation (yield : 0,8%), have been analysed by means of GC-FID and GC/MS. The results indicate clearly the occurrence of two chemotypes which are presently described. The former contains high proportions of piperitone oxide (19,7–31,4%) and piperitenone oxide (27,8–29,4%) respectively and the latter revealed piperitenone (54,9%) and piperitenone oxide (17,6%) as the major constituents. Such particular composition is reported for the first time within the M. rotundifolia species.
Does Invasion Success Reflect Superior Cognitive Ability? A Case Study of Two Congeneric Lizard Species (Lampropholis, Scincidae)
Chalene N. Bezzina, Joshua J. Amiel, Richard Shine
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0086271
Abstract: A species' intelligence may reliably predict its invasive potential. If this is true, then we might expect invasive species to be better at learning novel tasks than non-invasive congeners. To test this hypothesis, we exposed two sympatric species of Australian scincid lizards, Lampropholis delicata (invasive) and L. guichenoti (non-invasive) to standardized maze-learning tasks. Both species rapidly decreased the time they needed to find a food reward, but latencies were always higher for L. delicata than L. guichenoti. More detailed analysis showed that neither species actually learned the position of the food reward; they were as likely to turn the wrong way at the end of the study as at the beginning. Instead, their times decreased because they spent less time immobile in later trials; and L. guichenoti arrived at the reward sooner because they exhibited “freezing” (immobility) less than L. delicata. Hence, our data confirm that the species differ in their performance in this standardized test, but neither the decreasing time to find the reward, nor the interspecific disparity in those times, are reflective of cognitive abilities. Behavioural differences may well explain why one species is invasive and one is not, but those differences do not necessarily involve cognitive ability.
Induced pluripotent stem cell derived cardiomyocytes as models for cardiac arrhythmias
Maaike Hoekstra,Connie R. Bezzina,Arie O. Verkerk
Frontiers in Physiology , 2012, DOI: 10.3389/fphys.2012.00346
Abstract: Cardiac arrhythmias are a major cause of morbidity and mortality. In younger patients, the majority of sudden cardiac deaths have an underlying Mendelian genetic cause. Over the last 15 years, enormous progress has been made in identifying the distinct clinical phenotypes and in studying the basic cellular and genetic mechanisms associated with the primary Mendelian (monogenic) arrhythmia syndromes. Investigation of the electrophysiological consequences of an ion channel mutation is ideally done in the native cardiomyocyte (CM) environment. However, the majority of such studies so far have relied on heterologous expression systems in which single ion channel genes are expressed in non-cardiac cells. In some cases, transgenic mouse models have been generated, but these also have significant shortcomings, primarily related to species differences. The discovery that somatic cells can be reprogrammed to pluripotency as induced pluripotent stem cells (iPSC) has generated much interest since it presents an opportunity to generate patient- and disease-specific cell lines from which normal and diseased human CMs can be obtained These genetically diverse human model systems can be studied in vitro and used to decipher mechanisms of disease and identify strategies and reagents for new therapies. Here, we review the present state of the art with respect to cardiac disease models already generated using IPSC technology and which have been (partially) characterized. Human iPSC (hiPSC) models have been described for the cardiac arrhythmia syndromes, including LQT1, LQT2, LQT3-Brugada Syndrome, LQT8/Timothy syndrome and catecholaminergic polymorphic ventricular tachycardia (CPVT). In most cases, the hiPSC-derived cardiomyoctes recapitulate the disease phenotype and have already provided opportunities for novel insight into cardiac pathophysiology. It is expected that the lines will be useful in the development of pharmacological agents for the management of these disorders.
Solution for Rational Expectation Models Free of Complex Numbers  [PDF]
Frank Hespeler
Theoretical Economics Letters (TEL) , 2011, DOI: 10.4236/tel.2011.13011
Abstract: This paper approaches the problem of the potential for complex-valued solutions within linear macroeconomic models with rational expectations. It finds that these problems are associated with a specific solution method for the underlying model. The paper establishes that the danger of complex-valued solutions always can be eliminated by forcing those solutions to fulfill additional constraints. These constraints are essentially restrictions on the degrees of freedoms in indeterminate solutions.
A Characterization of the Optimal Management of Heterogeneous Environmental Assets under Uncertainty  [PDF]
Frank Raymond
Theoretical Economics Letters (TEL) , 2012, DOI: 10.4236/tel.2012.25093
Abstract: The application herein involves the optimal management of renewable and nonrenewable resources within the context of a stochastic model of optimal control. By characterizing the two dimensional Bellman solution, three rules with respect to resource management are established. Within the context of coastal development, this analysis may help to explain why renewable resources may become increasingly vulnerable to random external shocks as nonrenewable resources are depleted. Although existence of an optimal closed form solution to the multi-sector Bellman model remains an open mathematical question, this analysis offers a characterization which can be applied to other scenarios in economics or finance in which two assets following stochastic processes interact.
Investigating the Suitability of Agile Methods for Requirements Development of Home Care Systems  [PDF]
Sandra Kelly, Frank Keenan
Journal of Software Engineering and Applications (JSEA) , 2010, DOI: 10.4236/jsea.2010.39104
Abstract: The ageing population in developed countries brings many benefits but also many challenges, particularly in terms of the development of appropriate technology to support their ability to remain in their own home environment. One particular challenge reported for such Home Care Systems (HCS) is the identification of an appropriate requirements development technique for dealing with the typical diverse stakeholders involved. Agile Methods (AMs) recognize this challenge and propose techniques that could be useful. This paper examines the desirable characteristics identified for requirements development in HCS and investigates the extent to which agile practices conform to these. It also sets out future work to improve the situation for the non compliant points found.
Free Anterolateral Thigh Perforator Flap for Head and Neck Cancer Resection in a Nonagenarian  [PDF]
Frank Lin, Damien Grinsell
Modern Plastic Surgery (MPS) , 2012, DOI: 10.4236/mps.2012.21001
Abstract: With an aging population, free flap reconstruction for head and neck cancer ablation in the elderly is becoming more commonplace. In nonagenarians, however, such major operations are still rarely offered due to its physiological demands. We report the first case of successful resection and reconstruction of head and neck cancer with a free perforator flap in a 96 year old patient. We feel that with careful patient and flap selection, careful preoperative workup and close collaboration between treating teams, age alone should not preclude patients from receiving the best possible curative treatment and reconstruction in head and neck cancers. Even in nonagenarians, perforator free flaps, such as the anterolateral thigh flap, can be used safely to achieve good functional and aesthetic outcomes.
Optical Modeling and Analysis of Peripheral Optics of Contact Lenses  [PDF]
Jie Shen, Frank Spors
Open Journal of Ophthalmology (OJOph) , 2012, DOI: 10.4236/ojoph.2012.23012
Abstract: Background: Degraded peripheral vision has been hypothesized to be a stimulus for the development of foveal refractive error. Contact lenses have been widely used to correct central vision, but their impacts on peripheral vision are still unknown. The purpose of this study was to use optical model software to evaluate the peripheral optics of rigid gas permeable (RGP) and soft contact lenses (SCLs) in isolation. This will better assist us in understanding their peripheral optical performances on human eyes. Methods: An optical design software package (Zemax EE) was used to model peripheral optics of Menicon RGP lens and Acuvue 2 SCLs. Profiles of sphero-cylindrical power and major higher-order aberrations were computed in 10osteps out to 40o off-axis eccentricity for –3.0 D central focal power contact lens. The results of optical modeling were analyzed and compared with previously published experimental data. Results: –3.0 D RGP lenses and SCLs had –1.4 D and –2.0 D dioptric power at 40o eccentricity, respectively. The reduced dioptric power in the periphery of the analyzed contact lenses quantitatively matched with the reduced amount of hyperopic field curvature found from experimental data when these contact lenses fitted on human eyes. Cylindrical power increased to 0.3 D ~ 0.4 D at 40o eccentricity for both lens types. In addition, both contact lens types produced higher order aberrations, namely 1.2 μm coma and 0.15 μm spherical aberration at 40o eccentricity. Conclusions: Compared to SCLs, RGP lenses with equal focal power had less dioptric power in the periphery. Both RGP lenses and SCLs produced the same amount of major higher-order aberrations with increasing of the field angle. Some of these results can be used to predict and understand the peripheral optical performance of contact lenses on human eyes.
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