Effect of alloying elements on the microstructure property relationship in thermomechanically processed C-Mn-Si TRIP steels

The effect of additions of Nb, Al and Mo to Fe-C-Mn-Si TRIP steel on the final microstructure and mechanical properties after simulated  thermomechanical processing (TMP) has been studied. The laboratory simulations of discontinuous cooling during TMP were performed using a hot rolling mill. All samples were characterised using optical microscopy and image analysis. The volume fraction of retained austenite was ascertained using a heat tinting technique and X-ray diffraction measurements. Room temperature mechanical properties were determined by a tensile test. From this a comprehensive understanding of the structural aspect of the bainite transformation in these types of TRIP steels has been developed. The  results have shown that the final microstructures of thermomechanically processed TRIP steels comprise 50 % of polygonal ferrite, 7 - 12 % of retained austenite, non-carbide bainitic structure and martensite. All steels exhibited a good combination of ultimate tensile strength and total elongation. The microstructure-property examination revealed the relationship between the composition of TRIP steels and their mechanical properties. It has been shown that the addition of Mo to the C-Si-Mn-Nb TRIP steel increases the ultimate tensile strength up to 1020 MPa. The stability of the retained austenite of the Nb-Mo steel was degraded, which led to a decrease in the elongation (24 %). The results have demonstrated that the addition of Al to C-Si-Mn-Nb steel leads to a good combination of strength (∼ 940 MPa) and elongation (∼ 30 %) due to the formation of refined acicular ferrite and granular bainite structure with ∼7 - 8 % of stable retained austenite. Furthermore, it has been found that the addition of Al increases the volume fraction of bainitic ferrite laths. The investigations have shown an interesting result that, in the Nb-Mo-Al steel, Al has a more pronounced effect on the microstructure in comparison with Mo. It has been found that the bainitic structure of the Nb-Mo-Al steel appears to be more granular than in the Nb-Mo steel. Moreover, the volume fraction of the retained austenite increased (12 %) with decreasing bainitic ferrite content. The results have demonstrated that this steel has the best mechanical properties (1100 MPa and 28 % elongation). It has been concluded that the combined effect of Nb, Mo, and Al addition on the dispersion of the bainite, martensite and retained austenite in the ferrite matrix and the morphology of these phases is different than effect of Nb, Mo and Al, separately.

The last five amino acid residues at the C-terminus of PRK1 /KKN is essential for full lipid responsiveness

PRK1/PKN is a member of the protein kinase C (PKC) superfamily of serine/threonine protein kinases. Despite its important role as a RhoA effector, limited information is available regarding how this kinase is regulated. We show here that the last seven amino acid residues at the C-terminus is dispensable for the catalytic activity of PRK1 but is critical for the in vivo stability of this kinase. Surprisingly, the intact hydrophobic motif in PRK1 is dispensable for 3-phosphoinositide-dependent kinase-1 (PDK-1) binding and phosphorylation of the activation loop, as the PRK1-Δ940 mutant lacking the last two residues of the hydrophobic motif and the last 5 residues at the C-terminus interacts with PDK-1 in vivo and has a similar specific activity as the wild-type protein. We also found that the last four amino acid residues at the C-terminus of PRK1 is critical for the full lipid responsiveness as the PRK1-Δ942 deletion mutant is no longer activated by arachidonic acid. Our data suggest that the very C-terminus in PRK1 is critically involved in the control of the catalytic activity and activation by lipids. Since this very C-terminal segment is the least conserved among members of the PKC superfamily, it would be a promising target for isozyme-specific pharmaceutical interventions.

Effect of alloying elements on the microstructure-property relationship in thermomechanically processed C-Mn-Si TRIP steels

The effect of additions of Nb, Al and Mo to Fe-C-Mn-Si TRIP steel on the final microstructure and mechanical properties after simulated thermomechanical processing (TMP) has been studied. The laboratory simulations of discontinuous cooling during TMP were performed using a hot rolling mill. All samples were characterised using optical microscopy and image analysis. The volume fraction of retained austenite was ascertained using a heat tinting technique and X-ray diffraction measurements. Room temperature mechanical properties were determined by a tensile test. From this a comprehensive understanding of the structural aspect of the bainite transformation in these types of TRIP steels has been developed. The results have shown that the final microstructures of thermomechanically processed TRIP steels comprise 50 % of polygonal ferrite, 7 - 12 % of retained austenite, non-carbide bainitic structure and martensite. All steels exhibited a good combination of ultimate tensile strength and total elongation. The microstructure-property examination revealed the relationship between the composition of TRIP steels and their mechanical properties. It has been shown that the addition of Mo to the C-Si-Mn-Nb TRIP steel increases the ultimate tensile strength up to 1020 MPa. The stability of the retained austenite of the Nb-Mo steel was degraded, which led to a decrease in the elongation (24 %). The results have demonstrated that the addition of Al to C-Si-Mn-Nb steel leads to a good combination of strength (∼ 940 MPa) and elongation (∼ 30 %) due to the formation of refined acicular ferrite and granular bainite structure with ∼7 - 8 % of stable retained austenite. Furthermore, it has been found that the addition of Al increases the volume fraction of bainitic ferrite laths. The investigations have shown an interesting result that, in the Nb-Mo-Al steel, Al has a more pronounced effect on the microstructure in comparison with Mo. It has been found that the bainitic structure of the Nb-Mo-Al steel appears to be more granular than in the Nb-Mo steel. Moreover, the volume fraction of the retained austenite increased (12 %) with decreasing bainitic ferrite content. The results have demonstrated that this steel has the best mechanical properties (1100 MPa and 28 % elongation). It has been concluded that the combined effect of Nb, Mo, and Al addition on the dispersion of the bainite, martensite and retained austenite in the ferrite matrix and the morphology of these phases is different than effect of Nb, Mo and Al, separately.

Economic evaluation of a skin cancer prevention program in Australia : past achievements and future prospects

Objectives
Australia has the highest incidence of skin cancer in the world. Skin cancer prevention campaigns have been implemented in Australia for over two decades. The most notable is under the brand name, SunSmart. The aim of the current study is to assess the cost-effectiveness of SunSmart in the past and the potential cost-effectiveness of an ongoing national SunSmart program with optimal investment in the future.

Methods
An economic evaluation from a health sector perspective was conducted using the reduction in skin cancer incidence attributable to the SunSmart program modelled as the primary end-point. Historical SunSmart program expenditures were obtained from three representative states in three latitude zones, covering different levels of UVR exposure. Melanoma incidence rates from the three representative state cancer registers were used to model the health outcomes. Program effectiveness was assessed by the comparison between the well-resourced SunSmart state (Victoria) and the under-invested states (New South Wales and Queensland). Non-Melanoma Skin Cancer (NMSC) was modelled based on national survey results. 2003 was chosen as the reference year and future costs/outcomes over a 20 year time horizon were discounted at 3%.
The future level of investment in a national SunSmart was chosen to strengthen current practice by increasing current investment to a realistic and achievable level. This conservative increase in investment (expressed as ‘$ per capita’) reflected the investment level that has been achieved in Victoria over sustained periods. To model the potential cost-effectiveness of an upgraded national SunSmart program, a conservative approach was taken, whereby the same magnitude of effectiveness from 1988 to 2003 was applied to future skin cancer incidence.

Results
SunSmart in Victoria has saved 22,300 life-years, averted 27,900 disability-adjusted life-years(DALYs)(discounted) since its introduction in 1988 and achieved an incremental cost-effectiveness ratio (ICER) of $AUD 680 per life-year saved (LYS) and $AUD 540 per DALY averted. When the cost-offset from the estimated reduction in skin cancer treatment costs were taken into account, SunSmart achieved ‘dominance’. The net cost of SunSmart in the past was an estimated saving of $AUD 93 million. An upgraded national SunSmart for the next 20 years would save 91,000 life-years and avert 122,000 DALYs (discounted), involving an increased investment level from the current $AUD 0.07 per capita to the historical average of $AUD 0.28 per capita. The ICER for the upgraded SunSmart program was estimated at $AUD 940 per LYS and $AUD 700 per DALY averted. When the cost-offset is included, the program achieves dominance with a cost saving of $AUD 115 million – an estimated $AUD 2.32 return for every dollar invested between 2003 and 2022.

Conclusions
This study demonstrates that a sustained modest investment in skin cancer control is likely to be excellent value-for-money. While the available data base is certainly not prefect, key parameters would have to change dramatically for this conclusion to be challenged.

Urban–rural comparison of weight status among women and children living in socioeconomically disadvantaged neighbourhoods

Objective: To compare the weight status of women and children living in socioeconomically disadvantaged rural and urban neighbourhoods in Victoria.

Design, setting and participants: Cross-sectional study of data collected between August 2007 and July 2008 as part of the Resilience for Eating and Activity Despite Inequality (READI) study. Women aged 18–45 years living in 40 rural and 40 urban socioeconomically disadvantaged Victorian areas were surveyed by postal questionnaire. Data from a subset of their children aged 5–12 years were also analysed. Weight and height were self-reported for women and measured for children.

Main outcome measures: Women’s weight status based on body mass index (BMI): underweight; healthy; overweight; or obese Class I, II or III; children’s weight status based on International Obesity Taskforce BMI cut-off points.

Results: Of 11 940 women randomly selected, 4934 (41%) replied to a postal invitation to participate. After exclusions for various reasons, data were available on 3879 women and 636 of their children. Twenty-four per cent of urban and 26% of rural women were classified as overweight; a further 19% of urban and 23% of rural women were classified as obese. Twenty per cent of both urban and rural children were classified as overweight; a further 10% of urban and rural children were classified as obese. In crude analyses, rural women had higher odds of Class I and II obesity (odds ratio [OR], 1.34 and 1.72, respectively) compared with urban women. After adjusting for sociodemographic factors (age, number of children, country of birth, education level, employment status and marital status), there was no difference between urban and rural women in odds of overweight or obesity Class I, II or III. No significant urban–rural difference in odds of overweight/obesity was evident among children.

Conclusions: The higher prevalence of obesity in rural women compared with urban women was largely explained by individual-level sociodemographic factors, such as age, number of children, country of birth, education level, employment status and marital status. This suggests that higher obesity levels among women in rural areas may be attributable to the sociodemographic composition of these areas.

Multimodal nanostructured titanium using severe plastic deformation

In the present study, multimodal nanostructured titanium was engineered using severe plastic deformation. The multimodal structured titanium exhibits an ultrahigh strength of over 940 MPa and a large failure elongation of 24%. The ultrahigh strength is mainly derived from the nanostructured structures; whilst the exceptional ductility originates from the large fraction of high angle grain boundaries, micro-scale structures, and the non-equilibrium grain boundary configuration. It is worth noting that apart from dislocation slip processes, the formation of deformation twins reduced the effective slip distance and increased the strain hardening capacity via the Hall-Petch mechanism, leading to high ductility of the multimodal structured titanium.

Use of respiration rates of scyphozoan jellyfish to estimate their effects on the food web

One of the main objectives of research on jellyfish is to determine their effects on the food web. They are voracious consumers that have similar diets to those of zooplanktivorous fish, as well as eating microplankton and ichthyoplankton. Respiration rates (RRs) can be used to estimate the amount of food needed to balance metabolism, and thereby estimate minimum ingestion. We compiled RRs for scyphozoan medusae in three suborders (Semeaostomeae, Rhizostomeae, and Coronatae) to determine if a single regression could relate RRs to mass for diverse scyphomedusan species. Temperature (7–30°C) was not a significant factor. RRs versus wet weight (WW) regressions differed significantly for semeaostome and rhizostome medusae; however, RRs versus carbon mass over five-orders of magnitude did not differ significantly among suborders. RRs were isometric against medusa carbon mass, with data for all species scaling to the power 0.94. The scyphomedusa respiration rate (SRR) regression enables estimation of RR for any scyphomedusa from its carbon mass. The error of the SRR regression was ±72%, which is small in comparison with the 1,000-fold variation in field sampling. This predictive equation (RR in ml O2 d−1 = 83.37 * g C0.940) can be used to estimate minimum ingestion by scyphomedusae without exhaustive collection of feeding data. In addition, effects of confinement on RRs during incubation of medusae were tested. Large medusae incubated in small container volumes (CV) relative to their size (ratios of CV:WW < 50) had RRs ~one-tenth those of medusae in relatively larger containers. Depleted oxygen during incubation did not depress RRs of the medusae; however, swimming may have been restricted and respiration reduced in consequence. We briefly review other problems with RR experiments and suggest protocols and limitations for estimating ingestion rates of jellyfish from metabolic rates.