Pollution and cardiovascular health in Malta : a review

The leading cause of global mortality is cardiovascular disease (CVD) and in 2016 alone over 17 million premature deaths were attributed to CVD.1 Whilst previously there was only weak evidence to suggest an association of air pollution as a risk factor for CVD2, in recent years, the impact of air pollution has emerged as an independent, strong and modifiable risk factor for CVD. The importance of air pollution on CVD is now being considered above other more traditional factors such as high cholesterol and reduced physical activity.3 Exposure to fine particulate matter has been shown to increase the risk of acute coronary syndromes, yet more concerning are the studies which have shown the greater extent of its effects over a longer period of time, reducing life-expectancy by a number of years and being responsible for 19% of cardiovascul­­ar mortality (>3 million deaths).1 The purpose of this review is to identify significant studies investigating air pollution and its effects on cardiovascular health while also considering our situation in Malta, as a small, highly populated country.peer-reviewe

Heart failure with preserved ejection fraction and diabetes mellitus

Heart failure with preserved ejection fraction (HFpEF) constitutes approximately 50% of heart failure patients. The prevalence of diabetes mellitus in HFpEF is high at 30-40%. The paper provides a systematic review of the pathophysiological features underlying HFpEF in diabetes mellitus. The importance of mechanisms other than left ventricular diastolic dysfunction underlying this important condition is emphasised. Thus, ventricular-arterial coupling & vascular dysfunction together with chronotropic incompetence & cardiovascular reserve dysfunction play an important role. The various morphologic and molecular features occurring in the myocardium and vasculature in diabetes secondary to hyperglycaemia and other metabolic disturbances are also discussed. These include microangiopathy, myocardial fibrosis, increased oxidative stress, impaired calcium homeostasis, activation of the cardiac renin-angiotensin system, autonomic neuropathy, endothelial dysfunction, re-expression of foetal gene response as well as stem cell involvement. Nonetheless, a lot is still unknown and further studies are needed to establish the underlying pathophysiological mechanisms with the hope that novel pharmacotherapies targeting this disease will be developed. In the meantime, cardiometabolic factors, including hyperglycaemia, hypertension and dyslipidaemia should be targeted and aggressively treated.peer-reviewe

Design and development of a reduced form-factor high accuracy three-axis teslameter

Acknowledgments: The authors would like to thank Reuben Debono for his useful guidance and help in the PCB assembly of the instruments at the Electronic Systems Lab at the Faculty of Engineering at University of Malta. The authors would like to thank R. Ganter, project leader of the Athos undulator beamline and H-H. Braun, SwissFEL machine director, for their constant support throughout the entire project. The authors would like to thank Sasa Spasic and his team at Sentronis facilities for their fruitful discussions and their guidance during testing.A novel three-axis teslameter and other similar machines have been designed and developed for SwissFEL at the Paul Scherrer Institute (PSI). The developed instrument will be used for high fidelity characterisation and optimisation of the undulators for the ATHOS soft X-ray beamline. The teslameter incorporates analogue signal conditioning for the three-axes interface to a SENIS Hall probe, an interface to a Heidenhain linear absolute encoder and an on-board high-resolution 24-bit analogue-to-digital conversion. This is in contrast to the old instrumentation setup used, which only comprises the analogue circuitry with digitization being done externally to the instrument. The new instrument fits in a volumetric space of 150 mm × 50 mm × 45 mm, being very compact in size and also compatible with the in-vacuum undulators. This paper describes the design and the development of the different components of the teslameter. Performance results are presented that demonstrate offset fluctuation and drift (0.1–10 Hz) with a standard deviation of 0.78 µT and a broadband noise (10–500 Hz) of 2.05 µT with an acquisition frequency of 2 kHz.peer-reviewe

An advective mechanism for Deep Chlorophyll Maxima formation in southern Drake Passage

We observe surface and subsurface fluorescence-derived chlorophyll maxima in southern Drake Passage during austral summer. Backscatter measurements indicate that the deep chlorophyll maxima (DCMs) are also deep biomass maxima, and euphotic depth estimates show that they lie below the euphotic layer. Subsurface, offshore and near-surface, onshore features lie along the same isopycnal, suggesting advective generation of DCMs. Temperature measurements indicate a warming of surface waters throughout austral summer, capping the winter water (WW) layer and increasing off-shelf stratification in this isopycnal layer. The outcrop position of the WW isopycnal layer shifts onshore, into a surface phytoplankton bloom. A lateral potential vorticity (PV) gradient develops, such that a down-gradient PV flux is consistent with offshore, along-isopycnal tracer transport. Model results are consistent with this mechanism. Subduction of chlorophyll and biomass along isopycnals represents a biological term not observed by surface satellite measurements which may contribute significantly to the strength of the biological pump in this region

Calibration and characterization of a reduced form-factor high accuracy three-axis teslameter

A new reduced form-factor three axes digital teslameter, based on the spinning current technique, has been developed. This instrument will be used to characterize the SwissFEL insertion devices at the Paul Scherrer Institute (PSI) for the ATHOS soft X-ray beamline. A detailed and standardized calibration procedure is critical to optimize the performance of this precision instrument. This paper presents the measurement techniques used for the corrective improvements implemented through non-linearity, temperature offset, temperature sensitivity compensation of the Hall probe and electronics temperature compensation. A detailed quantitative analysis of the reduction in errors on the application of each step of the calibration is presented. The percentage peak error reduction attained through calibration of the instrument for reference fields in the range of ±2 T is registered to drop from 1.94% down to 0.02%.peer-reviewe

Performance analysis of a reduced form-factor high accuracy three-axis teslameter

In the framework of the SwissFEL project at the Paul Scherrer Institute (PSI), a Hall probe bench is being developed for the high-precision magnetic characterization of the insertion devices for the ATHOS soft X-ray beamline. For this purpose, a novel three-axis teslameter has been developed, which will be placed between the undulator and its outer shell in a very limited volumetric space of 150 × 50 × 45 mm. Together with a SENIS® 3-axis Hall probe at the center of the cross sectional area of the undulator, the setup will traverse along the undulator length on a specifically designed rig with minimal vibrations. This teslameter has all the analog signal conditioning circuitry for the Hall probe and also has on board 24-bit digitization. The instrument also handles an interface to a linear absolute encoder. The old instrumentation used only had analog signal conditioning circuitry whilst digitization was done off board. The new instrument also provides a very accurate magnetic field map in the µT range with simultaneous readings from the position encoder at an accuracy of ±3 µm. In this paper, a series of tests are described, which were performed at PSI in order to establish the measuring precision and repeatability of the instrument.peer-reviewe