Temporal Dissociation between Myeloperoxidase (MPO)-Modified LDL and MPO Elevations during Chronic Sleep Restriction and Recovery in Healthy Young Men

OBJECTIVES: Many studies have evaluated the ways in which sleep disturbances may influence inflammation and the possible links of this effect to cardiovascular risk. Our objective was to investigate the effects of chronic sleep restriction and recovery on several blood cardiovascular biomarkers. METHODS AND RESULTS: Nine healthy male non-smokers, aged 22-29 years, were admitted to the Sleep Laboratory for 11 days and nights under continuous electroencephalogram polysomnography. The study consisted of three baseline nights of 8 hours sleep (from 11 pm to 7 am), five sleep-restricted nights, during which sleep was allowed only between 1 am and 6 am, and three recovery nights of 8 hours sleep (11 pm to 7 am). Myeloperoxidase-modified low-density lipoprotein levels increased during the sleep-restricted period indicating an oxidative stress. A significant increase in the quantity of slow-wave sleep was measured during the first recovery night. After this first recovery night, insulin-like growth factor-1 levels increased and myeloperoxidase concentration peaked. CONCLUSIONS: We observed for the first time that sleep restriction and the recovery process are associated with differential changes in blood biomarkers of cardiovascular disease

Modelling the dispersion of flashing jets using CFD

Original article can be found at: http://www.sciencedirect.com/ Copyright Elsevier [Full text of this article is not available in the UHRA]Risk assessments related to industrial environments where gas is kept in liquid form under high pressure rely on the results from predictive tools. Computational Fluid Dynamics (CFD) is one such predictive tool and it is currently used for a range of applications. One of the most challenging application areas is the simulation of multiphase flows resulting from a breach or leakage in a pressurised pipeline or a vessel containing liquefied gas. The present paper deals with the modelling of the post-flashing scenario of a jet emanating from a circular orifice. In addition to being based on the equations governing fluid flow, the models used are those related to turbulence, droplet transport, evaporation, break-up and coalescence. Some of these models are semi-empirical and based on the data from applications other than flashing. However, these are the only models that are currently available in commercial codes and that would be used by consulting engineers for the type of modelling discussed above, namely the dispersion of a flashing release. A method for calculating inlet boundary conditions after flashing is also presented and issues related to such calculations are discussed. The results from a number of CFD based studies are compared with available experimental results. The results show that whilst a number of features of the experimental results can be reproduced by the CFD model, there are also a number of important shortcomings. The shortcomings are highlighted and discussed. Finally, an optimum approach to modelling of this type is suggested and methods to overcome modelling difficulties are proposed.Peer reviewe

An overview of ballast water treatment methods

Full text of this paper is not available in the UHRAOne of the greatest threats to the world's oceans is the transfer and potential introduction of harmful organisms in environments to which they are not indigenous. Ballast water deposited by marine vessels has been identified as a key factor responsible for this transfer and introduction. The significance of transferral of species has led to diverse research and development into ballast water treatment methods. However, despite the number of ballast water management techniques in development, at present the exchange of ballast water in open oceans is the only management technique widely used. This paper provides an overview of Ballast Water Treatment techniques currently at a research or development stage. An assessment of the potential effectiveness of each method, its corrosion implications and economic cost are all presented together with preliminary recommendations and an outline of future work

Modelling two-phase flows using CFD

Two-phase flows are encountered in a wide range of industrial and natural situations. Due to their complexity such flows have been investigated only analytically and experimentally. New computing facilities provide the flexibility to construct computational models that are easily adapted to a wide variety of physical conditions without constructing a large-scale prototype or expensive test rigs. But there is an inherent uncertainty in the numerical predictions due to stability, convergence and accuracy. The importance of a well-placed mesh is highlighted in the modelling of two-phase flows in horizontal pipelines.

An experimental study of stratified flow in enclosures

Original article can be found at: http://www.sciencedirect.com/ Copyright Elsevier [Full text of this article is not available in the UHRA]This paper presents all experimental investigation of flow scenarios that lead to stratification within the ventilated enclosures. The effect of supply terminal and extract terminal at various airflow rates on the flow characteristics is experimentally investigated. It has been found that relative influence of inertia and buoyancy forces resolves the stratified flow characteristics. The stratification interface level height and the ventilation flow rates are two main factors in the design of natural ventilation system. The results can be used to obtain a good estimation of the effectiveness of a ventilation system at design stage.Peer reviewe