The effect of light on the thermoluminescence of quartz

Thesis (M.Sc.) -- University of Adelaide, Dept. of Physics, 198

Weight management for patients in general practice tailored to health literacy

Our aim was to develop and evaluate the feasibility and impact of a PHC approach to weight management tailored to the level of health literacy of obese patients. There were three key activities undertaken in this regard: 1) a literature review; 2) a pilot study; and 3) a weight management trial called “Better Management of Weight in General Practice” (BMWGP). In this report we describe the three activities and use the BMWGP baseline data to explore three issues. First, we look at the effectiveness of a screening tool to identify patients with low health literacy in general practice. Second, we describe the association between health literacy and a range of factors, behavioural intentions, lifestyle behaviours and quality of life to better understand the link between health literacy and health in a population of patients with obesity attending general practices. Third, we identify the groups most likely to experience weight stigma and how stigma relates to health literacy.The research reported in this paper is a project of the Australian Primary Health Care Research Institute which is supported by a grant from the Australian Government Department of Health and Ageing under the Primary Health Care Research Evaluation and Development Strategy

Single-grain TT-OSL bleaching characteristics: Insights from modern analogues and OSL dating comparisons

Previous assessments of thermally transferred optically stimulated luminescence (TT-OSL) signal resetting in natural sedimentary settings have been based on relatively limited numbers of observations, and have been conducted primarily at the multi-grain scale of equivalent dose (De) analysis. In this study, we undertake a series of single-grain TT-OSL bleaching assessments on nineteen modern and geological dating samples from different sedimentary environments. Daylight bleaching experiments performed over several weeks confirm that single-grain TT-OSL signals are optically reset at relatively slow, and potentially variable, rates. Single-grain TT-OSL residual doses range between 0 and 24 Gy for thirteen modern samples, with >50% of these samples yielding weighted mean De values of 0 Gy at 2σ. Single-grain OSL and TT-OSL dating comparisons performed on well-bleached and heterogeneously bleached late Pleistocene samples from Kangaroo Island, South Australia, yield consistent replicate age estimates. Our results reveal that (i) single-grain TT-OSL residuals can potentially be reduced down to insignificant levels when compared with the natural dose range of interest for most TT-OSL dating applications; (ii) the slow bleaching properties of TT-OSL signals may not necessarily limit their dating applicability to certain depositional environments; and (iii) non-trivial differences may be observed between single-grain and multi-grain TT-OSL bleaching residuals in some modern samples. Collectively, these findings suggest that single-grain TT-OSL dating may offer advantages over multi-grain TT-OSL dating in certain complex depositional environments

Impact of rare earth doping on the luminescence of lanthanum aluminum silicate glasses for radiation sensing

Large core soft glass fibers have been demonstrated to be promising candidates as intrinsic fiber sensors for radiation detection and dosimetry applications. Doping with rare earth ions enhanced their radiation sensitivity. SiO2-Al2O3-La2O3 (SAL) glasses offer easy fabrication of large core fibers with high rare earth concentration and higher mechanical strength than soft glasses. This paper evaluates the suitability of the SAL glass type for radiation dosimetry based on optically stimulated luminescence (OSL) via a comprehensive investigation of the spectroscopic and dosimetric properties of undoped and differently rare earth doped bulk SAL glass samples. Due to the low intensity of the rare earth luminescence peaks in the 250–400 nm OSL detection range, the OSL response for all the SAL glasses is not caused by the rare earth ions but by radiation-induced defects that act as intrinsic centers for the recombination of electrons and holes produced by the ionizing radiation, trapped in fabrication induced defect centers, and then released via stimulation with 470 nm light. The rare earth ions interfere with these processes involving intrinsic centers. This dosimetric behavior of highly rare earth doped SAL glasses suggests that enhancement of OSL response requires lower rare earth concentrations and/or longer wavelength OSL detection range

Volume 35, AMT-1 Cruise Report and Preliminary Results

This report documents the scientific activities on board the Royal Research Ship (RRS) 'James Clark Ross' during the irst Atlantic Meridional Transect (AMT-1), 21 September to 24 October 1995. The ship sailed from Grimsby (England) for Montevideo (Uruguay) and then continued on to Stanley (Falkland Islands). The primary objective of the AMT program is to investigate basic biological processes in the open Atlantic Ocean over very broad spatial scales. For AMT-1, the meridional range covered was approximately 50 deg N to 50 deg S or nearly 8,000 nmi. The measurements to be taken during the AMT cruises are fundamental for the calibration, validation, and continuing understanding of remotely sensed observations of biological oceanography. They are also important for understanding plankton community structure over latitudinal scales and the role of the world ocean in global carbon cycles. During AMT-1 a variety of instruments were used to map the physical, chemical, and biological structure of the upper 200 m of the water column. Ocean color measurements were made using state-of-the-art sensors, whose calibration was traceable to the highest international standards. New advances in fluorometry were used to measure photosynthetic activity, which was then used to further interpret primary productivity. A unique set of samples and data were collected for the planktonic assemblages that vary throughout the range of the transect. These data will yield new interpretations on community composition and their role in carbon cycling. While the various provinces of the Atlantic Ocean were being crossed, the partial pressure of CO2 was related to biological productivity. This comparison revealed the areas of drawdown of atmospheric CO2 and how these areas relate to the surrounding biological productivity. These data, plus the measurements of light attenuation and phytoplankton optical properties, will be used as a primary input for basin-scale biological productivity models to help develop ecosystem dynamics models which will be important for improving the forecasting abilities of modelers. The AMT program is also attempting to meet the needs of international agencies in their implementation of Sensor Intercomparison and Merger for Biological and Interdisciplinary Ocean Studies (SIMBIOS), a program to develop a methodology and operational capability to combine data products from the various ocean color satellite missions

Impact of Point-of-Care Testing on the Management of Sexually Transmitted Infections in South Africa: Evidence from the HVTN702 Human Immunodeficiency Virus Vaccine Trial.

BACKGROUND: Alternative approaches to syndromic management are needed to reduce rates of sexually transmitted infections (STIs) in resource-limited settings. We investigated the impact of point-of-care (POC) versus central laboratory-based testing on STI treatment initiation and STI adverse event (STI-AE) reporting. METHODS: We used Kaplan-Meier and Cox regression models to compare times to treatment initiation and STI-AE reporting among HVTN702 trial participants in South Africa. Neisseria gonorrhoeae (NG) and Chlamydia trachomatis (CT) were diagnosed POC at eThekwini clinic and in a central laboratory at Verulam/Isipingo clinics. All clinics used POC assays for Trichomonas vaginalis (TV) testing. RESULTS: Among 959 women (median age, 23 [interquartile range, 21-26] years), median days (95% confidence interval [95%CI]) to NG/CT treatment initiation and NG/CT-AE reporting were 0.20 (.16-.25) and 0.24 (.19-.27) at eThekwini versus 14.22 (14.12-15.09) and 15.12 (13.22-21.24) at Verulam/Isipingo (all P .05). Cox regression analysis revealed that NG/CT treatment initiation (adjusted hazard ratio [aHR], 39.62 [95%CI, 15.13-103.74]) and NG/CT-AE reporting (aHR, 3.38 [95%CI, 2.23-5.13]) occurred faster at eThekwini versus Verulam/Isipingo, while times to TV treatment initiation (aHR, 0.93 [95%CI, .59-1.48]) and TV-AE reporting (aHR, 1.38 [95%CI, .86-2.21]) were similar. CONCLUSIONS: POC testing led to prompt STI management with potential therapeutic and prevention benefits, highlighting its utility as a diagnostic tool in resource-limited settings

Explosives detection by fluorescence quenching of conjugated polymers in suspended core optical fibers

In this work we demonstrate a suspended core microstructured optical fiber-based sensor platform forexplosives detection based on the fluorescence quenching of a surface-attached conjugated polymerpoly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV). These fibers allow for strongevanescent field interactions with the surrounding media because of their small core size, and can sam-ple minute liquid volumes. This is the first demonstration of a fluorescent conjugated polymer sensorcapable of measuring liquid explosives samples loaded within an optical fiber. This technique is used toidentify 1,4-dinitrobenzene (DNB), a member of the nitroaromatics family of explosives, in acetone forconcentrations as low as 6.3 ppm in a total sampling volume of 27 nl and to quantify its concentrationusing the fluorescence decay lifetime, requiring an analysis time of only a few minutes.Fenghong Chu, Georgios Tsiminis, Nigel A. Spooner, Tanya M. Monr

Identification and quantification of explosives in nanolitre solution volumes by Raman spectroscopy in suspended core optical fibers

A novel approach for identifying explosive species is reported, using Raman spectroscopy in suspended core optical fibers. Numerical simulations are presented that predict the strength of the observed signal as a function of fiber geometry, with the calculated trends verified experimentally and used to optimize the sensors. This technique is used to identify hydrogen peroxide in water solutions at volumes less than 60 nL and to quantify microgram amounts of material using the solvent’s Raman signature as an internal calibration standard. The same system, without further modifications, is also used to detect 1,4-dinitrobenzene, a model molecule for nitrobenzene-based explosives such as 2,4,6-trinitrotoluene (TNT).Georgios Tsiminis, Fenghong Chu, Stephen C. Warren-Smith, Nigel A. Spooner and Tanya M. Monr

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead