The occurrence of trans-18:1 isomers in plasma lipids classes in humans

Objective: The aim of this study was to examine the distribution of trans fatty acids (TFA) in plasma lipid classes and the relationship with dietary intake of TFA.

Design: After a 2 week baseline (habitual) diet, all subjects consumed a moderate fat (MF) diet for 3 weeks with the fat being derived mainly from margarine and the rest from lean beef, and then a very low fat (VLF) diet for 3 weeks with the TFA being derived only from the lean beef. Blood samples were collected 2 days prior to the end and also on the last day of each dietary period.

Setting: Deakin Institute of Human Nutrition, Deakin University, Geelong, Australia.

Subjects: Ten free-living mildly hypercholesterolaemic subjects aged 22-66 were recruited in Geelong.

Outcome measures: TFA intake was calculated from analyses of Australian margarines, butter, lean meat and animal fat. The TFA in plasma lipid fractions were separated by AgNO3 thin-layer chromatography and quantitated by capillary gas-liquid chromatography using internal standards.

Results: The phospholipid (PL) fraction contained more than 60% of the trans-18:1 isomers in the plasma lipids in all subjects. On the baseline diet, the predominant positional isomer of trans-18:1 in PL was Delta11, whereas in the other lipid classes it was the Delta9 isomer. The concentration of the Delta9 isomer increased on the MF diet, particularly in the PL fraction, while the concentration of the Delta11 isomer decreased in all fractions. On the VLF diet, the total TFA level decreased by approximately 50%, mainly due to decreases in the TFA isomers in the PL and TG fractions. Changes in plasma total and PL TFA, PL Delta9, Delta10 and Delta11 were strongly correlated with dietary TFA intake (P<0.0001). There were also significant association between dietary TFA intake and PL Delta12 (P=0.003), triacylglycerol Delta9 (P=0.009), Delta11 (P=0.0005), total triacylglycerol (P=0.023) and free fatty acid TFA (P=0.042).

Conclusions: The results suggest that the measurement of trans-18:1 in plasma PL and TAG, and plasma total TFA could be used to estimate the intake of TFA.

Effect of heat-treatment atmosphere on the bond strength of apatite layer on Ti substrate

Objectives
The purpose of this study was to investigate the bond strength of apatite layer on titanium (Ti) substrate coated by biomimetic method and to improve the bonding of apatite layer to Ti substrate by optimizing the alkali heat-treatment process.

Methods
Ti plates pre-treated with an alkali solution of 10 M sodium hydroxide (NaOH) were heat-treated at 600 °C for 1 h at different atmospheres: in air and in vacuum. A dense apatite layer formed on top of the sodium titanate layer after soaking the alkali and heat-treated Ti samples in simulated body fluid (SBF) for up to 3 weeks. The bond strengths of the sodium titanate layer on Ti substrate, and apatite layer on the sodium titanate layer, were measured, respectively, by applying a tensile load. The fracture sites were observed with a scanning electron microscope (SEM).

Results
The apatite layer on the substrate after alkali heat-treatment in air achieved higher bond strength than that on the substrate after alkali heat-treatment in vacuum. It was found that the interfacial structure between the sodium titanate and Ti substrate has a significant influence on the bond strength of the apatite layer.

Significance
It is advised that titanium implants can achieve better osseointegration under load-bearing conditions by depositing an apatite layer in vivo on a Ti surface subjected to alkali and heat-treated in air.

Nonadditivity of faradaic currents and modification of double layer capacitance in the voltammetry of mixtures of ferrocene and ferrocenium salts in ionic liquids

Electrochemical studies on the Fc + e− Fc+ (Fc = ferrocene) process have been undertaken via the oxidation of Fc and reduction of Fc+ as the hexafluorophosphate (PF6−) or tetrafluoroborate (BF4−) salts and their mixtures in three ionic liquids (ILs) (1-butyl-1-methylpyrrolidinium bis[(trifluoromethyl)sulfonyl]imide, 1-butyl-3-methylimidazolium tetrafluoroborate, and 1-butyl-3-methylimidazolium hexafluorophosphate). Data obtained at macro- and microdisk electrodes using conventional dc and Fourier-transformed large-amplitude ac (FT-ac) voltammetry reveal that diffusion coefficients for Fc and Fc+ differ significantly and are a function of the Fc and Fc+ concentration, in contrast to findings in molecular solvents with 0.1 M added supporting electrolyte media. Thus, the Faradaic currents associated with the oxidation of Fc (Fc0/+) and reduction of FcPF6 or FcBF4 (Fc+/0) when both Fc and Fc+ are simultaneously present in the ILs differ from values obtained when individual Fc and Fc+ solutions are used. The voltammetry for both the Fc0/+ and Fc+/0 processes exhibited near-Nernstian behavior at a glassy carbon macrodisk electrode and a platinum microdisk electrode, when each process was studied individually in the ILs. As expected, the reversible formal potentials (E°′) and diffusion coefficients (D) at 23 ± 1 °C were independent of the electrode material and concentration. However, when Fc and FcPF6 or FcBF4 were both present, alterations to the mass transport process occurred and apparent D values calculated for Fc and Fc+ were found to be about 25−39% and 32−42% larger, respectively, than those determined from individual solutions. The apparent value of the double layer capacitance determined by FT-ac voltammetry from individual and mixed Fc and Fc+ conditions at the GC electrode was also a function of concentration. Double layer capacitance values increased significantly with the concentration of Fc and FcPF6 or FcBF4 when species were studied individually or simultaneously, but had a larger magnitude under conditions where both species were present. Variation in the structure of the ILs and hence mobilities of the ionic species, when Fc and FcPF6 or FcBF4 are simultaneously present, is considered to be the origin of the nonadditivity of the Faradaic currents and variation in capacitance.

A survey of cloud-based service computing solutions for mammalian genomics

Cloud-based service computing has started to change the way how research in science, in particular biology, medicine, and engineering, is being carried out. Researchers in the area of mammalian genomics have taken advantage of cloud computing technology to cost-effectively process large amounts of data and speed up discovery. Mammalian genomics is limited by the cost and complexity of analysis, which require large amounts of computational resources to analyse huge amount of data and biology specialists to interpret results. On the other hand the application of this technology requires computing knowledge, in particular programming and operations management skills to develop high performance computing (HPC) applications and deploy them on HPC clouds. We carried out a survey of cloud-based service computing solutions, as the most recent and promising instantiations of distributed computing systems, in the context their use in research of mammalian genomic analysis. We describe our most recent research and development effort which focuses on building Software as a Service (SaaS) clouds to simplify the use of HPC clouds for carrying out mammalian genomic analysis.

StressCloud: a tool for analysing performance and energy consumption of cloud applications

Finding the best deployment configuration that maximises energy efficiency while guaranteeing system performance of cloud applications is an extremely challenging task. It requires the evaluation of system performance and energy consumption under a wide variety of realistic workloads and deployment configurations. This paper demonstrates StressCloud, an automatic performance and energy consumption analysis tool for cloud applications in real-world cloud environments. StressCloud supports 1) the modelling of realistic cloud application workloads, 2) the automatic generation and running of load tests, and 3) the profiling of system performance and energy consumption. A demonstration video can be accessed at: https://www.youtube.com/watch?v=0l4-a-CNtVQ.

Blended learning and the flipped classroom: The affordances of cloud based, located, and virtual world environments to support student learning

In this paper the author reports on the introduction of the flipped classroom integrating located, online and virtual world learning environments to support the collaborative lived experiences of a group of students and the educator participating in a higher education undergraduate art unit, Navigating the Visual World. A qualitative narrative methodology, A/r/tography, incorporating both image making and textual recording is used to explore and identify interwoven aspects of the artist/ researcher/ educator relationship in the creative artistic process of exploring concepts of identity within inquiry based art practice. Selected student examples, including a collaborative group assessment project demonstrate effective student engagement with experiential blended learning within the flipped classroom.

Mode of oral iron administration and the amount of iron habitually consumed do not affect iron absorption, systemic iron utilisation or zinc absorption in iron-sufficient infants: a randomised trial

Different metabolic pathways of supplemental and fortification Fe, or inhibition of Zn absorption by Fe, may explain adverse effects of supplemental Fe in Fe-sufficient infants. We determined whether the mode of oral Fe administration or the amount habitually consumed affects Fe absorption and systemic Fe utilisation in infants, and assessed the effects of these interventions on Zn absorption, Fe and Zn status, and growth. Fe-sufficient 6-month-old infants (n 72) were randomly assigned to receive 6·6 mg Fe/d from a high-Fe formula, 1·3 mg Fe/d from a low-Fe formula or 6·6 mg Fe/d from Fe drops and a formula with no added Fe for 45 d. Fractional Fe absorption, Fe utilisation and fractional Zn absorption were measured with oral (⁵⁷Fe and ⁶⁷Zn) and intravenous (⁵⁸Fe and ⁷⁰Zn) isotopes. Fe and Zn status, infection and growth were measured. At 45 d, Hb was 6·3 g/l higher in the high-Fe formula group compared with the Fe drops group, whereas serum ferritin was 34 and 35 % higher, respectively, and serum transferrin 0·1 g/l lower in the high-Fe formula and Fe drops groups compared with the low-Fe formula group (all P<0·05). No intervention effects were observed on Fe absorption, Fe utilisation, Zn absorption, other Fe status indices, plasma Zn or growth. We concluded that neither supplemental or fortification Fe nor the amount of Fe habitually consumed altered Fe absorption, Fe utilisation, Zn absorption, Zn status or growth in Fe-sufficient infants. Consumption of low-Fe formula as the only source of Fe was insufficient to maintain Fe stores.