Examining the effect of ionic constituents on crystallization fouling on heat transfer surfaces

The effect of the most abundant constituents in potable water on fouling of aluminium surface has been studied systematically in this work. The role of sodium, chloride, magnesium and sulphate ions and total organic carbon (TOC) on the fouling kinetics and morphology was assessed using a once-through open flow cell. The findings showed that the fouling resistance to heat transfer increases with the concentration of chloride and sodium. A complex influence of magnesium was found on the scaling process, varying between inhibition and promotion of scale formation depending on the concentration. At high concentrations of Mg2+, the formed scale layer consists of needle-like aragonite coated by a crust of magnesium deposits. The inhibitory performance of sulphate SO42− was found to be insignificant when compared with Mg2+ under similar conditions. Even though it is undesirable in potable water, inhibition efficiencies of TOC were 31.3% and 47.9% at concentrations of 2 and 4.3 mg/L respectively. The morphology observations illustrated that the presence of TOC produces a rough scale layer

Inorganic mineral precipitation from potable water on heat transfer surfaces

In this study, an experimental approach mimicking processes encountered in electric kettles has been designed toinvestigate the influence of heating and cooling rate, and water composition on the kinetics of inorganic saltprecipitation taking place when water is heated from ambient temperature up to its boiling point. The kinetics ofsalt precipitation in the bulk solution have been monitored through turbidity measurements as well as trackingion concentration throughout the heating/cooling process and the experimentalfindings highlight the criticalrole of the cooling step on the overall amount of salts that precipitate. The presence of magnesium ions in thewater was found to influence the precipitation of calcium carbonate which was found to be the dominant saltcrystallising out of solution; calcium sulphate was not observed

Rapid identification and antimicrobial susceptibility profiling of Gram-positive cocci in blood cultures with the Vitek 2 system

Rapid identification and antimicrobial susceptibility profiling of the bacteria in blood cultures can result in clinical and financial benefits. Addition of saponin to the fluid from blood culture bottles promotes the recovery of the bacteria and thus may shorten the turnaround time of the microbiological analyses. In this study we compared the identification and susceptibility profiles of saponin-treated and untreated (standard method) blood cultures monomicrobial for Gram-positive cocci using Vitek 2. We concordantly identified 49 (89%) of 55 monobacterial cultures using the results with the standard method as reference. Complete categorical agreement between the susceptibility profiles with the new and the standard method was found for 26 (53%) of 49 isolates, while discrepancies were seen for 23 (47%) cultures. E-tests indicated that the new method resulted in a correct susceptibility profile for 8 (35%) of these 23 blood cultures. Therefore, 34 (69%) of 49 cultures showed a concordant/correct susceptibility profile for all antimicrobials with an overall error rate of 2.3%. Thus, addition of saponin to the fluid from blood culture bottles of the Bactec 9240 leads to the rapid (results available ≥12 hours earlier) and reliable identification and susceptibility profiling of Gram-positive cocci in blood cultures with Vitek 2

Update on the third international stroke trial (IST-3) of thrombolysis for acute ischaemic stroke and baseline features of the 3035 patients recruited

Intravenous recombinant tissue plasminogen activator (rtPA) is approved in Europe for use in patients with acute ischaemic stroke who meet strictly defined criteria. IST-3 sought to improve the external validity and precision of the estimates of the overall treatment effects (efficacy and safety) of rtPA in acute ischaemic stroke, and to determine whether a wider range of patients might benefit

Eating disorders: the current status of molecular genetic research

Anorexia nervosa (AN) and bulimia nervosa (BN) are complex disorders characterized by disordered eating behavior where the patient’s attitude towards weight and shape, as well as their perception of body shape, are disturbed. Formal genetic studies on twins and families suggested a substantial genetic influence for AN and BN. Candidate gene studies have initially focused on the serotonergic and other central neurotransmitter systems and on genes involved in body weight regulation. Hardly any of the positive findings achieved in these studies were unequivocally confirmed or substantiated in meta-analyses. This might be due to too small sample sizes and thus low power and/or the genes underlying eating disorders have not yet been analyzed. However, some studies that also used subphenotypes (e.g., restricting type of AN) led to more specific results; however, confirmation is as yet mostly lacking. Systematic genome-wide linkage scans based on families with at least two individuals with an eating disorder (AN or BN) revealed initial linkage regions on chromosomes 1, 3 and 4 (AN) and 10p (BN). Analyses on candidate genes in the chromosome 1 linkage region led to the (as yet unconfirmed) identification of certain variants associated with AN. Genome-wide association studies are under way and will presumably help to identify genes and pathways involved in these eating disorders. The elucidation of the molecular mechanisms underlying eating disorders might improve therapeutic approaches

Nothing Lasts Forever: Environmental Discourses on the Collapse of Past Societies

The study of the collapse of past societies raises many questions for the theory and practice of archaeology. Interest in collapse extends as well into the natural sciences and environmental and sustainability policy. Despite a range of approaches to collapse, the predominant paradigm is environmental collapse, which I argue obscures recognition of the dynamic role of social processes that lie at the heart of human communities. These environmental discourses, together with confusion over terminology and the concepts of collapse, have created widespread aporia about collapse and resulted in the creation of mixed messages about complex historical and social processes