Measurement of turbulent flame speed of natural gas/air mixtures at elevated pressure

Turbulent flame speeds were measured over a range of pressures to 0.8 MPa using a jet flow apparatus fired with a synthetic mixture representing a mid-European natural gas. The equivalence ratio empty set was 0.9. The gas contained significant proportions of ballast gases and higher hydrocarbons. The method adopted was the 'flame angle' technique, using schlieren imaging to obtain the flame vertex angle from the peak density gradient. Image analysis techniques were developed to reduce interpretation errors and give an unbiased result. The data show higher flame speeds than those obtained with pure methane at elevated pressures, using similar methodology, and has an application in numerical modelling of combustors

Outcome and human epidermal growth factor receptor (HER) 1–4 status in invasive breast carcinomas with proliferation indices evaluated by bromodeoxyuridine labelling

BACKGROUND: We have shown previously that whereas overexpression of human epidermal growth factor receptor (HER)1, HER2 and HER3 is associated with poor prognosis in breast cancer, HER4 is associated with a good prognosis. Cell proliferation is a key component of aggressive cancers and is driven by growth factors. In this study, bromodeoxyuridine (BrdU)-derived proliferation indices are correlated with clinical outcome and HER1–4 status for further clarification of the differing roles for the HER family at a biological level. METHODS: Seventy-eight invasive breast cancers had BrdU labelling in vivo to determine the BrdU labelling index (BLI) and the potential tumour doubling time (T(pot)). Long-term clinical follow-up was available for these patients. We used immunohistochemistry to establish the HER1–4 status in 55 patients from the BrdU cohort. RESULTS: We demonstrate a significant correlation between high BLI values and breast cancer-specific death (P = 0.0174). Low T(pot )times were also significantly correlated with breast cancer-specific death (P = 0.0258). However, BLI did not independently predict survival in Cox's multiple regression analysis when combined with other prognostic factors such as size, grade and nodal status. Tumours found to be positive for HER1, HER2 or HER3 had significantly (P = 0.041) higher labelling indices, with HER1 also showing significantly higher indices when considered independently (P = 0.024). Conversely, HER4 positivity was significantly correlated (P = 0.013) with low BLI values, in line with previous data associating this receptor with good prognosis tumours. CONCLUSIONS: These results support the hypothesis that HER1–3 are associated with driving tumour proliferation, whereas HER4 is involved in a non-proliferative or even protective role

Can Research Assessments Themselves Cause Bias in Behaviour Change Trials? A Systematic Review of Evidence from Solomon 4-Group Studies

BACKGROUND: The possible effects of research assessments on participant behaviour have attracted research interest, especially in studies with behavioural interventions and/or outcomes. Assessments may introduce bias in randomised controlled trials by altering receptivity to intervention in experimental groups and differentially impacting on the behaviour of control groups. In a Solomon 4-group design, participants are randomly allocated to one of four arms: (1) assessed experimental group; (2) unassessed experimental group (3) assessed control group; or (4) unassessed control group. This design provides a test of the internal validity of effect sizes obtained in conventional two-group trials by controlling for the effects of baseline assessment, and assessing interactions between the intervention and baseline assessment. The aim of this systematic review is to evaluate evidence from Solomon 4-group studies with behavioural outcomes that baseline research assessments themselves can introduce bias into trials. METHODOLOGY/PRINCIPAL FINDINGS: Electronic databases were searched, supplemented by citation searching. Studies were eligible if they reported appropriately analysed results in peer-reviewed journals and used Solomon 4-group designs in non-laboratory settings with behavioural outcome measures and sample sizes of 20 per group or greater. Ten studies from a range of applied areas were included. There was inconsistent evidence of main effects of assessment, sparse evidence of interactions with behavioural interventions, and a lack of convincing data in relation to the research question for this review. CONCLUSIONS/SIGNIFICANCE: There were too few high quality completed studies to infer conclusively that biases stemming from baseline research assessments do or do not exist. There is, therefore a need for new rigorous Solomon 4-group studies that are purposively designed to evaluate the potential for research assessments to cause bias in behaviour change trials

Schlieren methods for high pressure turbulent jet flames

Turbulent flame speeds of a premixed synthetic natural gas mixture were measured using a jet flow apparatus over a range of pressures to 0·8 MPa at an equivalence ratio of 0·9. The method adopted was the 'flame angle' technique, using schlieren imaging to obtain the flame vertex angle from the peak density gradient. Image analysis techniques were developed to reduce interpretation errors and to give information on the velocity and combined gradient distribution local to the flame fro