Recrystallization during and following hot working of magnesium alloy AZ31

The microstructures of magnesium AZ31 are examined following hot compression testing and annealing. The grain size, fraction dynamically recrystallized and, in a couple of cases, the crystallographic texture are reported. It was found that the progress of dynamic recrystallization is strongly sensitive to processing conditions but that the dynamically
recrystallized grain size was less sensitive to stress than in other metals. It was also found that, for structures containing between 80 and 95 % dynamic recrystallization, abnormal grain growth occurs during annealing. The crystallographic texture produced is also sensitive to the deformation conditions.

Investigation of processing conditions of melded parts to determine process boundaries

Melding, a novel method for producing seamless joints in thermosetting composites utilising the Quickstep™ process, is explored in this paper. The effect of processing conditions on the quality of melded joins is examined and a set of processing boundaries defined so that the strength of melded joints is optimized. HexPly® 914c pre-preg material was exposed to a range of processing temperatures prior to joining via the melding process. Differential Scanning Calorimetry analysis was carried out to investigate the degree of cure of material prior to final joining, and it was found that minimal cure occurs at temperatures below 120°C. After consolidation and cure of the melded parts, short beam shear testing was conducted to evaluate the strength of the melded interface. Exposure temperatures between 65°C and 120°C were found to optimize short beam shear join strength. Mode I double cantilever beam and mode II end notched flexural tests showed no detrimental effect of elevated exposure temperatures prior to joining.

Melding: a new alternative to adhesive bonding

Melding, a novel method for joining composites is examined in this paper. The method uses Quickstep ™ technology to retain partially cured areas of a composite laminate, enabling subsequent bonding operations. The effect of melding on the mechanical properties of the composite has been investigated. Flexural testing of HexPly 914 indicates consistent properties throughout a melded section. Flexural strength values of 1.36±O.03 GPa compared to 1.35±O.03 GPa for a standard laminate were recorded. In order to achieve sufficient bond strength, the portion of the composite to be joined must have a significant proportion of uncured matrix. The ability of Hexply 914 prepreg to retain sufficient bonding potential to form a strong joint was also investigated. HexPly 914 Lap Shear results indicated no significant variation in strength values between co-cured and melded joins, with a recorded
strength value of 15.0±0. 7 MPa.

Study on thermoplastic-modified multifunctional epoxies : influence of heating rate on cure behaviour and phase separation

The effect of heating rate on the cure behaviour and phase separation of thermoplastic-modified epoxy systems was investigated. Polyethersulphone (PES) modified multifunctional epoxies, triglycidyl-aminophenol (TGAP) and tetraglycidyldiaminodiphenylmethane (TGDDM), as well T300/914 prepreg were used. It was shown that heating rate had a significant influence on the cure kinetics and phase structures of investigated systems. Greater heating rate causes higher epoxy conversion. The domain size of the macrophases formed from phase separation increases with the increase of heating rate. A more complete phase separation is achieved by fast heated thermoplastic-modified epoxy blends.

Calcaneal ultrasound reference ranges for Australian men and women : the Geelong Osteoporosis Study

Summary Heel ultrasound is a more portable modality for assessing fracture risk than dual-energy X-ray absorptiometry and does not use ionising radiation. Fracture risk assessment requires appropriate reference data to enable comparisons. This study reports the first heel ultrasound reference ranges for the Australian population.

Introduction This study aimed to develop calcaneal (heel) ultrasound reference ranges for the Australian adult population using a population-based random sample.

Methods Men and women aged ≥20 years were randomly selected from the Barwon Statistical Division in 2001–2006 and 1993–1997, respectively, using the electoral roll. Broadband ultrasound attenuation (BUA), speed of sound (SOS) and stiffness index (SI) were measured at the heel using a Lunar Achilles Ultrasonometer. Gender-specific means and standard deviations for BUA, SOS and SI were calculated for the entire sample (men 20–93 years, n = 1,104; women 20–92 years, n = 914) and for participants aged 20–29 years (men, n = 157; women, n = 151). Associations between ultrasound measures and age were examined using linear regression.

Results For men, mean ± standard deviation BUA, SOS and SI were 118.7 ± 15.8 dB/MHz, 1,577.0 ± 43.7 m/s and 100.5 ± 20.7, respectively; values for women were consistently lower (111.0 ± 16.4 dB/MHz, P < 0.001; 1,571.0 ± 39.0 m/s, P = 0.001; and 93.7 ± 20.3, P < 0.001, respectively). BUA was higher in young men compared with young women (124.5 ± 14.4 vs 121.0 ± 15.1 dB/MHz), but SOS (1,590.1 ± 43.1 vs 1,592.5 ± 35.0 m/s) and SI (108.0 ± 19.9 vs 106.3 ± 17.7) were not. The relationships between age and each ultrasound measure were linear and negative across the age range in men; associations were also negative in women but non-linear.

Conclusion These data provide reference standards to facilitate the assessment of fracture risk in an Australian population using heel ultrasound.

Surface modification and properties analysis of shell powder with sodium stearate surface modifier

In this study, shell powder was modified by sodium stearate surface modifier for improving the compatibility of SP with polymer materials. The surface modifiers influence on the physical and chemical properties of SP were studied by scanning electron microscope(SEM), fourier infrared spectrum(FT-IR), surface contact angle meter, XRD diffraction analysis meter and other modern instruments and analysis method. The results showed that the surface modifier was successfully coupled to the shell powder surface. After surface modifier modification, the interfacial compatibility of the shell powder with polymer materials was effectively improved. The contact angle of shell powder surface increased from 73.5 ° to 110.8 °, along with the dosage of sodium stearate surface modifier was 4.0%. All results suggested that modified shell powder is promising for using as a reinforcement filler in polymer materials. © (2014) Trans Tech Publications, Switzerland.

Depression as a risk factor for fracture in women: a 10 year longitudinal study

BACKGROUND: Previous research has demonstrated deficits in bone mineral density (BMD) among individuals with depression. While reduced BMD is a known risk for fracture, a direct link between depression and fracture risk is yet to be confirmed. METHODS: A population-based sample of women participating in the Geelong Osteoporosis Study was studied using both nested case-control and retrospective cohort study designs. A lifetime history of depression was identified using a semi-structured clinical interview (SCID-I/NP). Incident fractures were identified from radiological reports and BMD was measured at the femoral neck using dual energy absorptiometry. Anthropometry was measured and information on medication use and lifestyle factors was obtained via questionnaire. RESULTS: Among 179 cases with incident fracture and 914 controls, depression was associated with increased odds of fracture (adjusted odds ratio (OR) 1.57, 95%CI 1.04-2.38); further adjustment for psychotropic medication use appeared to attenuate this association (adjusted OR 1.52, 95%CI 0.98-2.36). Among 165 women with a history of depression at baseline and 693 who had no history of depression, depression was associated with a 68% increased risk of incident fracture (adjusted hazard ratio (HR) 1.68, 95%CI 1.02-2.76), with further adjustment for psychotropic medication use also appearing to attenuate this association (adjusted HR 1.58, 95%CI 0.95-2.61). LIMITATIONS: Potential limitations include recall bias, unrecognised confounding and generalizability. CONCLUSIONS: This study provides both cross-sectional and longitudinal evidence to suggest that clinical depression is a risk factor for radiologically-confirmed incident fracture, independent of a number of known risk factors. If there is indeed a clinically meaningful co-morbidity between mental and bone health, potentially worsened by psychotropic medications, the issue of screening at-risk populations needs to become a priority.

Covert dose reduction is a distinct type of medication non-adherence observed across all care settings in inflammatory bowel disease.

BACKGROUND: Non-adherence by dose omission is common and deleterious to outcomes in Inflammatory Bowel Disease (IBD), but covert dose reduction (CDR) remains unexplored. AIMS: To determine frequency and attitudinal predictors of overall medication non-adherence and of covert dose reduction as separate entities. METHODS: A cross sectional questionnaire was undertaken involving IBD patients in three different geographical regions and care settings. Demographics, medication adherence by dose omission, and rate of patient initiated dose reduction of conventional meds without practitioner knowledge (CDR) were assessed, along with attitudes toward IBD medication. RESULTS: Of 473 respondents (mean age 50.3 years, 60.2% female) frequency of non-adherence was 21.9%, and CDR 26.9% (p<0.001). By logistic regression, significant independent predictors of non-adherence were dissatisfaction with the patient-doctor relationship (p<0.001), depression (p=0.001), anxiety (p=0.047), and negative views regarding medication efficacy (p<0.001) or safety (p=0.017). Independent predictors of covert dose reduction included regular complementary medicine (CAM) use (p<0.001), experiencing more informative (p<0.001) and comfortable (p=0.006) consultations with alternative practitioners, disbelieving doctor delivered information (p=0.021) and safety concerns regarding conventional medication (p<0.001). Neither the frequency of non-adherence (p=0.569) nor CDR (p=0.914) differed between cohorts by different treatment settings. CONCLUSIONS: Covert dose reduction of IBD medication is more common than omission of medication doses, predicted by different factors to usual non-adherence, and has not been previously reported in IBD. The strongest predictor of CDR is regular CAM use.

Changes in Australian injecting drug users’ mental health problems and service uptake from 2006-2012

Purpose– The purpose of this paper is to assess changes in rates of mental health problems and service utilisation for Australian regular injecting drug users (IDUs) from 2006 to 2012. Design/methodology/approach – Data were taken from Illicit Drug Reporting System national surveys with 914 regular IDUs in 2006 and 883 in 2012. Changes in rates of self-reported mental health problems and service use were assessed. Findings – Rates of self-reported mental health problems increased from 38.3 per cent in 2006 to 43.7 per cent in 2012 – mainly due to increases in anxiety rates. Conversely, there was a decrease in mental health service use from 70.2 to 58.4 per cent by 2012. However, there was a proportional increase in the use of psychologists. These trends remained after controlling for socio-demographic and medical differences between the 2006/2012 samples. K10 scores for 2012 participants validated the use of the self-report measures. Practical implications – Reductions in stigma, improvements in mental health literacy, and modest increases in anxiety may explain increases in self-report of mental health problems. Stagnant service utilisation rates in an expanding population willing to self-report may explain decreasing service use. The introduction of key mental health reforms also may have contributed, particularly with the increase in psychologist access. This paper highlights the need for improved population monitoring of mental health in disadvantaged groups such as IDUs. Originality/value – This paper is the first to assess changes in mental health outcomes over time in Australian IDUs. This examination covered a critical era in the mental health landscape, with significant increases in public awareness campaigns and major mental health reforms.