Measurement of the ^{13}C(α, n_{0})^{16}O Differential Cross Section from 0.8 to 6.5 MeV

The cross section of the ^{13}C(α,n)^{16}O reaction is needed for nuclear astrophysics and applications to a precision of 10% or better, yet inconsistencies among 50 years of experimental studies currently lead to an uncertainty of ≈15%. Using a state-of-the-art neutron detection array, we have performed a high resolution differential cross section study covering a broad energy range. These measurements result in a dramatic improvement in the extrapolation of the cross section to stellar energies potentially reducing the uncertainty to ≈5% and resolving long standing discrepancies in higher energy data.

New Measurement of ^{12}C+^{12}C Fusion Reaction at Astrophysical Energies

Carbon and oxygen burning reactions, in particular, ^{12}C+^{12}C fusion, are important for the understanding and interpretation of the late phases of stellar evolution as well as the ignition and nucleosynthesis in cataclysmic binary systems such as type Ia supernovae and x-ray superbursts. A new measurement of this reaction has been performed at the University of Notre Dame using particle-γ coincidence techniques with SAND (a silicon detector array) at the high-intensity 5U Pelletron accelerator. New results for ^{12}C+^{12}C fusion at low energies relevant to nuclear astrophysics are reported. They show strong disagreement with a recent measurement using the indirect Trojan Horse method. The impact on the carbon burning process under astrophysical scenarios will be discussed.

In-situ calibration of laser/galvo scanning system using dimensional reference artefacts

Laser powder bed fusion systems use a high-power laser, steered by two galvanometer (galvo) mirrors to scan a pattern on metal powder layers. Part geometric tolerances depend on the positioning accuracy of the laser/galvo system. This paper describes an in-situ calibration technique utilizing a camera coaxially aligned with the laser imaging a dimensional reference artefact. The laser positions are determined from the images captured by the camera while scanning the artefact. The measurement uncertainty is estimated using simulations. The in-situ calibration results are compared with the results obtained from the typical 'mark and measure' galvo calibration method.

Hot Topics in Research: Preventive Neuroradiology in Brain Aging and Cognitive Decline

Preventive neuroradiology is a new concept supported by growing literature. The main rationale of preventive neuroradiology is the application of multimodal brain imaging toward early and subclinical detection of brain disease and subsequent preventive actions through identification of modifiable risk factors. An insightful example of this is in the area of age-related cognitive decline, mild cognitive impairment, and dementia with potentially modifiable risk factors such as obesity, diet, sleep, hypertension, diabetes, depression, supplementation, smoking, and physical activity. In studying this link between lifestyle and cognitive decline, brain imaging markers may be instrumental as quantitative measures or even indicators of early disease. The purpose of this article is to provide an overview of the major studies reflecting how lifestyle factors affect the brain and cognition aging. In this hot topics review, we will specifically focus on obesity and physical activity.

The neuroprogressive nature of major depressive disorder: pathways to disease evolution and resistance, and therapeutic implications

In some patients with major depressive disorder (MDD), individual illness characteristics appear consistent with those of a neuroprogressive illness. Features of neuroprogression include poorer symptomatic, treatment and functional outcomes in patients with earlier disease onset and increased number and length of depressive episodes. In such patients, longer and more frequent depressive episodes appear to increase vulnerability for further episodes, precipitating an accelerating and progressive illness course leading to functional decline. Evidence from clinical, biochemical and neuroimaging studies appear to support this model and are informing novel therapeutic approaches. This paper reviews current knowledge of the neuroprogressive processes that may occur in MDD, including structural brain consequences and potential molecular mechanisms including the role of neurotransmitter systems, inflammatory, oxidative and nitrosative stress pathways, neurotrophins and regulation of neurogenesis, cortisol and the hypothalamic-pituitary-adrenal axis modulation, mitochondrial dysfunction and epigenetic and dietary influences. Evidence-based novel treatments informed by this knowledge are discussed.

Exercising the worry away: how inflammation, oxidative and nitrogen stress mediates the beneficial effect of physical activity on anxiety disorder symptoms and behaviours

Regular physical activity exerts positive effects on anxiety disorder symptoms, although the biological mechanisms underpinning this effect are incompletely understood. Numerous lines of evidence support inflammation and oxidative and nitrogen stress (O&NS) as important in the pathogenesis of mood and anxiety disorders, and physical activity is known to influence these same pathways. This paper reviews the inter-relationships between anxiety disorders, physical activity and inflammation and O&NS, to explore whether modulation of inflammation and O&NS may in part underpin the positive effect of physical activity on anxiety disorders. Numerous studies support the notion that physical activity operates as an anti-inflammatory and anti-O&NS agent which potentially exerts positive effects on neuroplasticity, the expression of neurotrophins and normal neuronal functions. These effects may therefore influence the expression and evolution of anxiety disorders. Further exploration of this area may elicit a deeper understanding of the pathogenesis of anxiety disorders, and inform the development of integrated programmes including PA specifically suited to the treatment and prevention of anxiety disorders and symptoms.

Use of fresh-frozen plasma at Royal Darwin Hospital: a retrospective audit

BACKGROUND

The aim of the study was to assess the appropriateness of use of fresh-frozen plasma (FFP) at Royal Darwin Hospital against the National Health and Medical Research Council and Australian and New Zealand Society for Blood Transfusion guidelines.

METHODS

A retrospective review of blood product request forms, online pathology storage system data, pathology records and clinical notes between 1 January 2006 and 31 December 2006 was carried out. The appropriateness of requests was assessed against existing guidelines. The percentage of appropriate and inappropriate FFP transfusions was obtained.

RESULTS

Six hundred and forty-eight of 950 units (68%) of FFP were used with an appropriate indication as per National Health and Medical Research Council/Australian and New Zealand Society for Blood Transfusion guidelines. Of the remaining units, 14% (137 units) was given without a clear indication and a decision of appropriateness could not be established for 17% (165 units) because of inadequate clinical or pathology information (e.g. coagulation results). Multiple issues around prescribing practice were identified.

CONCLUSION

There is significant use of FFP at Royal Darwin Hospital without clear clinical indication. The employment of a transfusion nurse to monitor use of FFP (and other blood products) and provide education is aimed at improving transfusion efficiency and patient safety.