Thermoelastic investigation of residual stress: plastic deformation and the change in thermoelastic constant

Plastic deformation causes very small changes in the thermoelastic response of metallic materials; this variation of the thermoelastic constant has the potential to form the basis of a new non-destructive, non-contact, full-field technique for residual stress assessment that is quicker and cheaper than existing methods. The effect of plastic strain on the thermoelastic constant is presented as a potential basis for a calibration methodology that reveals areas of a component that have experienced plastic strain. Establishing this basis provides the initial step in identifying a new approach to residual stress analysis using the thermoelastic response. An evaluation of initial calibration results is presented and the feasibility of applying the methodology to actual components is assessed. As the response to plastic strain is likely to be small it is necessary to identify the effects of the paint coating; experimental work is presented that highlights the importance of repeatable coating approaches

Simultaneous capacitance and amperometric measurements of exocytosis: a comparison

We measured the exocytotic response induced by flash photolysis of caged compounds in isolated mast cells and chromaffin cells. Vesicle fusion was measured by monitoring the cell membrane capacitance. The release of vesicular contents was followed by amperometry. In response to a GTP gamma S stimulus we found that the time integral of the amperometric current could be superimposed on the capacitance trace. This shows that the integrated amperometric signal provides an alternative method of measuring the extent and kinetics of the secretory response. Very different results were obtained when photolysis of caged Ca2+ (DM-nitrophen) was used to stimulate secretion. In mast cells, there was an immediate, graded increase in membrane capacitance that was followed by step increases (indicative of granule fusion). During the initial phase of the capacitance increases, no release of oxidizable secretory products was detected. In chromaffin cells we also observed a considerable delay between increases in capacitance, triggered by uncaging Ca2+, and the release of oxidizable secretory products. Here we demonstrate that there can be large increases in the membrane capacitance of a secretory cell, triggered by flash photolysis of DM-nitrophen, which indicate events that are not due to the fusion of granules containing oxidizable substances. These results show that increases in capacitance that are not resolved as steps cannot be readily interpreted as secretory events unless they are confirmed independently

Use of cumulative mortality data in patients with acute myocardial infarction for early detection of variation in clinical practice: observational study

OBJECTIVES: Use of cumulative mortality adjusted for case mix in patients with acute myocardial infarction for early detection of variation in clinical practice. DESIGN: Observational study. SETTING: 20 hospitals across the former Yorkshire region. PARTICIPANTS: All 2153 consecutive patients with confirmed acute myocardial infarction identified during three months. MAIN OUTCOME MEASURES: Variable life­adjusted displays showing cumulative differences between observed and expected mortality of patients; expected mortality calculated from risk model based on admission characteristics of age, heart rate, and systolic blood pressure. RESULTS: The performance of two individual hospitals over three months was examined as an example. One, the smallest district hospital in the region, had a series of 30 consecutive patients but had five more deaths than predicted. The variable life­adjusted display showed minimal variation from that predicted for the first 15 patients followed by a run of unexpectedly high mortality. The second example was the main tertiary referral centre for the region, which admitted 188 consecutive patients. The display showed a period of apparently poor performance followed by substantial improvement, where the plot rose steadily from a cumulative net lives saved of - 4 to 7. These variations in patient outcome are unlikely to have been revealed during conventional audit practice. CONCLUSIONS: Variable life­adjusted display has been integrated into surgical care as a graphical display of risk­adjusted survival for individual surgeons or centres. In combination with a simple risk model, it may have a role in monitoring performance and outcome in patients with acute myocardial infarction

Real-time PCR based on SYBR-Green I fluorescence: An alternative to the TaqMan assay for a relative quantification of gene rearrangements, gene amplifications and micro gene deletions

BACKGROUND: Real-time PCR is increasingly being adopted for RNA quantification and genetic analysis. At present the most popular real-time PCR assay is based on the hybridisation of a dual-labelled probe to the PCR product, and the development of a signal by loss of fluorescence quenching as PCR degrades the probe. Though this so-called 'TaqMan' approach has proved easy to optimise in practice, the dual-labelled probes are relatively expensive. RESULTS: We have designed a new assay based on SYBR-Green I binding that is quick, reliable, easily optimised and compares well with the published assay. Here we demonstrate its general applicability by measuring copy number in three different genetic contexts; the quantification of a gene rearrangement (T-cell receptor excision circles (TREC) in peripheral blood mononuclear cells); the detection and quantification of GLI, MYC-C and MYC-N gene amplification in cell lines and cancer biopsies; and detection of deletions in the OPA1 gene in dominant optic atrophy. CONCLUSION: Our assay has important clinical applications, providing accurate diagnostic results in less time, from less biopsy material and at less cost than assays currently employed such as FISH or Southern blotting

What is the source level of pile-driving noise in water?

To meet the growing demand for carbon-free energy sources, the European Union (EU) has ambitious plans to increase its capacity for generation of offshore wind power. The United Kingdom and The Netherlands, for example, plan to increase their offshore power-generating capacity to 33 and 6 GW, respectively, by the year 2020. Assuming that this power is generated entirely by wind and that a single wind turbine can generate up to 10 MW, at least 3,900 offshore turbines would be required by these two states alone to achieve this goal. A popular turbine construction method known as “pile driving” involves the use of hammering a steel cylinder (a “monopile”) into the seabed. A concern has arisen for the possible effect on mammals (Southall et al. 2007) and fish (Popper and Hastings 2009) of the sound produced by the succession of hammer impacts required to sink the pile to its required depth (tens of meters)

On the characterization of periodic generalized Horadam sequences

The Horadam sequence is a direct generalization of the Fibonacci numbers in the complex plane, which depends on a family of four complex parameters: two recurrence coefficients and two initial conditions. In this article a computational matrix-based method is developed to formulate necessary and sufficient conditions for the periodicity of generalized complex Horadam sequences, which are generated by higher order recurrences for arbitrary initial conditions. The asymptotic behaviour of generalized Horadam sequences generated by roots of unity is also examined, along with upper boundaries for the disc containing periodic orbits. Some applications are suggested, along with a number of future research directions

Premenopausal gynecologic surgery and survival among black and white women with breast cancer

Purpose: In the United States, hysterectomies and oophorectomies are frequently performed before menopause for benign conditions. The procedures are associated with reduced breast cancer-specific mortality among White women. The relationship between premenopausal gynecologic surgery and mortality in Black women with breast cancer is unknown. Methods: This investigation used incident invasive cases of breast cancer from Phases 1 and 2 of the Carolina Breast Cancer Study a population-based study that recruited Black and White women in North Carolina between 1993 and 2001. Premenopausal gynecologic surgery was operationalized in three categories: no surgery; hysterectomy with bilateral oophorectomy; hysterectomy with conservation of ≥ 1 ovary. Mortality was ascertained using the National Death Index, last updated in 2016. Multivariable-adjusted Cox Proportional Hazard Models were used to estimate the effect of premenopausal surgery on breast cancer-specific and all-cause mortality Results: Hysterectomy with bilateral oophorectomy was associated with reduced breast cancer-specific mortality (HR 0.68; 95% CI 0.49, 0.96). White and Black women had a similar reduction in breast cancer-specific mortality. (HR among white: 0.66; 95% CI 0.43, 1.02), (HR among Black: 0.67; 95% CI 0.37, 1.21). Conclusions: There was a similar reduction in breast cancer-specific mortality following premenopausal, pre-diagnosis hysterectomy with bilateral oophorectomy across both Black and White women

Genetic and environmental variation in methane emissions of sheep at pasture

A total of 2,600 methane (CH4) and 1,847 CO2 measurements of sheep housed for 1 h in portable accumulation chambers (PAC) were recorded at 5 sites from the Australian Sheep CRC Information Nucleus, which was set up to test leading young industry sires for an extensive range of current and novel production traits. The final validated dataset had 2,455 methane records from 2,279 animals, which were the progeny of 187 sires and 1,653 dams with 7,690 animals in the pedigree file. The protocol involved rounding up animals from pasture into a holding paddock before the first measurement on each day and then measuring in groups of up to 16 sheep over the course of the day. Methane emissions declined linearly (with different slopes for each site) with time since the sheep were drafted into the holding area. After log transformation, estimated repeatability (rpt) and heritability (h(2)) of liveweight-adjusted CH4 emissions averaged 25% and 11.7%, respectively, for a single 1-h measurement. Sire × site interactions were small and nonsignificant. Correlations between EBV for methane emissions and Sheep Genetics Australia EBV for production traits were used as approximations to genetic correlations. Apart from small positive correlations with weaning and yearling weights (r = 0.21-0.25, P < 0.05), there were no significant relationships between production trait and methane EBV (calculated from a model adjusting for liveweight by fitting separate slopes for each site). To improve accuracy, future protocols should use the mean of 2 (rpt = 39%, h(2) = 18.6%) or 3 (rpt = 48%, h(2) = 23.2%) PAC measurements. Repeat tests under different pasture conditions and time of year should also be considered, as well as protocols measuring animals directly off pasture instead of rounding them up in the morning. Reducing the time in the PAC from 1 h to 40 min would have a relatively small effect on overall accuracy and partly offset the additional time needed for more tests per animal. Field testing in PAC has the potential to provide accurate comparisons of animal and site methane emissions, with potentially lower cost/increased accuracy compared to alternatives such as SF6 tracers or open path lasers. If similar results are obtained from tests with different protocols/seasonal conditions, use of PAC measurements in a multitrait selection index with production traits could potentially reduce methane emissions from Australian sheep for the same production level