Effect of L-arginine infusion on glucose disposal during exercise in humans

<b>Purpose:b> We have previously shown that local infusion of a nitric oxide synthase (NOS) inhibitor attenuates increases in leg glucose uptake during exercise in humans. We have also shown that infusion of the NOS substrate, L-arginine (L-Arg), increases glucose clearance, although the mechanisms involved were not determined. A potential mechanism for NO-mediated glucose disposal is via interactions with NOS and the energy sensor AMPactivated protein kinase (AMPK). The aim of this study was to determine the mechanism(s) by which L-Arg infusion increases glucose disposal during exercise in humans by examining total NOS activity and AMPK signaling. <br /><br /><b>Methods:b> Seven males cycled for 120 min at 64% T 1% V˙ O2peak, during which the [6,6-2H]glucose tracer was infused. During the final 60 min of exercise, either saline alone (Control, CON), or saline containing L-Arg HCl (L-Arg, 30 g at 0.5 gIminj1) was coinfused in a double-blind, randomized, counterbalanced order. <br /><br /><b>Results:b> L-Arg increased the glucose rate of disappearance and glucose clearance rate during exercise; however, this was accompanied by a 150% increase in plasma insulin concentration from 65 to 75 min (P G 0.05) that remained significantly elevated until 90 min of exercise. Skeletal muscle AMPK signaling, nNOSK phosphorylation by AMPK, and total NOS activity increased to a similar extent in the two trials. <br /><br /><b>Conclusions:b> The increase in glucose disposal after L-Arg infusion during exercise is likely due to the significantly higher plasma insulin concentration.<br />

A facile method to fabricate carbon nanostructures via the self-assembly of polyacrylonitrile/poly (methyl methacrylate-b-polyacrylonitrile) AB/B' type block copolymer/homopolymer blends

The self-assembly and high temperature behavior of AB/B′ type block copolymer/homopolymer blends containing polyacrylonitrile (PAN) polymers were studied for the first time. Here, microphase separated nanostructures were formed in the poly(methyl methacrylate-b-polyacrylonitrile) (PMMAN) block copolymer and their blends with homopolymer PAN at various blend ratios. Additionally, these nanostructures were transformed into porous carbon nanostructures by sacrificing PMMA blocks via pyrolysis. Spherical and worm like morphologies were observed in both TEM and AFM images at different compositions. The thermal and phase behavior examinations showed good compatibility between the blend components in all studied compositions. The PAN homopolymer (B′) with a comparatively higher molecular weight than the corresponding block (B) of the block copolymer is expected to exhibit &lsquo;dry brush’ behavior in this AB/B′ type system. This study provides a basic understanding of the miscibility and phase separation in the PMMAN/PAN system, which is important in the nanostructure formation of bulk PAN based materials with the help of block copolymers to develop advanced functional materials.

You leaving me alone? The persistence of ethics during the Holocaust

Many Holocaust scholars subscribe to the theory that under the unimaginable stress of Holocaust persecution Jewish victims found that, in extremis, conventional morality did not apply. On the basis of an analysis of a sample of videotestimonies held in the Jewish Holocaust Museum and Research Centre in Melbourne, Australia (hereafter the JHMRC), this article argues that such assumptions require revision. Despite observing numerous instances of unconscionable behaviour, in these videotestimonies survivors provide many examples of their own ethical practices and those of others.<br />

Complexes of the tripodal nitrilotrimethylenetrisphosphonic (H6L) and P,P',P''-triphenylnitrilotrimethylenetrisphosphinic (H3L) acids with the copper(II) ion. Synthesis and charaterization of [Hpy][Cu(H3L)(H2O)] and [Cu(HL)(py)]2.2Me2CO

The complexes [Hpy][Cu(Hb>3b>L)(H2O)] <b>1b> (L⁶ = nitrilotrimethylenetrisphosphonate) and [Cu(HL°)(py)]b>2b>·2Meb>2b>CO <b>2b> [(L°)³ = P,P,P" -triphenylnitrilotrismethylenetrisphosphinate)] have been isolated and characterized by X-ray crystallography, near IR-visible spectroscopy and magnetic measurements. The structure determination has shown the complexes to be constituted by monomeric and dimeric units respectively. In the monomer the metal atom is surrounded by the phosphonate ligand and a water molecule, with a geometry between a trigonal bipyramid and a square pyramid. The two copper atoms in the dimer are held together by an arm of the tripod ligand, with a pyridine molecule as additional ligand, and display octahedral geometry. The presence of monomeric and dimeric species in aqueous solutions of <b>1b> and <b>2b> has been shown by ESMS studies. The formation in water solution of the dimer [{Cu(Hb>3b>L)}b>2b>]^2-, as a minor species, has been supported by potentiometric measurements, whereas only the monomeric anion [CuL°] has been ascertained to be present. In general the ligand Hb>3b>L° forms less stable copper(II) complexes than Hb>6b>L.<br /><br /><br />

Internet and competitive advantage in Australian professional sport organisations

The electronic revolution has proven to be a powerful stimulus for change in business practice. As a business tool however, the Internet must endure the same scrutiny under which other business activities are placed. If the use of the Internet in business is a sound strategy, then it must contribute toward competitive advantage. The sport business industry has not been isolated from the vagaries of Internet applications. Moreover, as the industry has become more competitive, forcing sporting organisations towards unprecedented levels of accountability and business practice, the Internet has been increasingly seen as a potential 'holy grail' for sport organisations struggling for revenue (Stewart & Smith, 1999). This research is a response to these pressures. It seeks to identify Internet based opportunities for competitive advantage, and to provide strategies and recommendations for the successful use of the Internet in Australian professional sport organisations. In realising this objective, a newly developed and integrated Business Activity Model has been constructed. The model assists in the identification of specific Internet based competitive advantage strategies, and provides a theoretical framework for this research. The Business Activity Model conceptualises, for the first time, the relationships between the value chain, constituents of electronically enabled competitive advantage, and the Internet. With Australia's limited group of fully professional sports capable of sustaining the human resources and budgets necessary to implement comprehensive e-commerce strategies, the organisations selected to participate in this research represent the pinnacle of Australian professional sport clubs. Specifically, the 55 clubs competing in the Australian Football League (A.F.L.), National Basketball League (N.B.L.), National Rugby League (N.R.L.), and National Soccer League (N.S.L.) constituted the research sample and population. In concert with the 87% participation rate, sampling approached a census. A telephone-administered survey, based primarily on the rigorously tested instrument developed by Sethi and King (1994), was employed for data collection. This research employs a comprehensive set of descriptive statistics, and is bolstered by a confirmatory and an exploratory factor analysis, undertaken on one component of the data. The outcome of this research was the identification of seven practical recommendations for Australian professional sport organisations seeking to improve competitive advantage via the Internet. These recommendations were based on an inventory of the 'gaps' between the strategies proposed by the literature, and the practices of the sample, and relate to both overall Internet strategy, and specific web site applications. The development of the new Business Activity Model and the identification of key online strategy themes support and complement these recommendations. An examination of variations in the practices of participating organisations, and some comparisons against United States sporting organisations, also provides depth and context to the findings. This research provides a platform for sport managers to effectively harness the potential of the Internet, through their web sites in particular, and realise significant competitive advantages. The Business Activity Model provides managers in all industries with a tool for the detection and understanding of potential elements of competitive advantage, and incorporates all activities critical to business in the new digital economy. Seven practical recommendations for improved online performance based on identified competitive advantage and strategies fulfils the primary objective of this research. E-commerce continues to grow at astronomical rates, and with the Internet poised to become the life-blood of 21st century sporting organisations, these recommendations will assist managers in their ongoing search for competitive advantage.

Effectiveness of a community-based osteoporosis education and self-management course : a wait list controlled trial

<b>Summary : b>Osteoporosis is an increasing burden on individuals and health resources. The Osteoporosis Prevention and Self-Management Course (OPSMC) was designed to assist individuals to prevent and manage osteoporosis; however, it had not been evaluated in an Australian setting. This randomised controlled trial showed that the course increased osteoporosis knowledge.<br /><b>Introduction and hypothesis :b> Osteoporosis is a major and growing public health concern. An OPSMC was designed to provide individuals with information and skills to prevent or manage osteoporosis, but its effectiveness has not previously been evaluated. This study aimed to determine whether OPSMC attendance improved osteoporosis knowledge, self-efficacy, self-management skills or behaviour.<b><br />Materials and methods : b>Using a wait list randomised controlled trial design, 198 people (92% female) recruited from the community and aged over 40 (mean age = 63) were randomised into control (n = 95) and intervention (n = 103) groups. The OPSMC consists of four weekly sessions which run for 2 h and are led by two facilitators. The primary outcome were osteoporosis knowledge, health-directed behaviour, self-monitoring and insight and self-efficacy.<br /><b>Results :b> The groups were comparable at baseline. At 6-week follow-up, the intervention group showed a significant increase in osteoporosis knowledge compared with the control group; mean change 3.5 (p &lt; 0.001) on a measure of 0–20. The intervention group also demonstrated a larger increase in health-directed behaviour, mean change 0.16 (p &lt; 0.05), on a measure of 0–6.<b><br />Conclusion :b> The results indicate that the OPSMC is an effective intervention for improving understanding of osteoporosis and some aspects of behaviour in the short term.<br />

Inspection of drop-weight impact damage in woven CFRP laminates fabricated by different processes

The influence of manufacturing process on the drop-weight impact damage in woven carbon/epoxy laminates was inspected by visual observation, dyepenetrant X-ray technique, and optical microscopy observation. The MTM56/ CF0300 woven quasi-isotropic laminates were fabricated by two processes: the autoclave and the Quickstep processes. Quickstep^TM is a novel composite manufacturing process, which was designed for the out-of-autoclave production of high-quality composite parts at lower cost. It utilizes higher heat conduction of fluid other than gas to transfer heat to components, which results in much shorter cure cycles. The laminates cured by this fast heating process showed different impact failure modes from those cured by the conventional autoclave process. The residual indentation in the top side of the Quickstep-cured laminates had a bigger diameter, but a smaller depth at the same impact energy level. Dye-penetrant X-ray revealed more intense and connected impact damage regions in the autoclave-cured laminates. Optical micrography as a supplementary method showed less severe matrix damage in the quickstep-cured laminates indicating a more ductile property of the resin matrix cured at a faster heating rate.<br />

Nonisothermal Crystallization Behavior of Poly(m-xylene adipamide)/Montmorillonite Nanocomposites

This article reports the nonisothermal crystallization behavior of MXD6 and its clay nanocomposite system (MXD6/MMT) using differential scanning calorimetry (DSC). The DSC experimental data were analyzed by theoretical modeling of the crystallization kinetics using the Avrami, Ozawa, Jeziorny, and the combined Avrami―Ozawa semiempirical models. It has been determined that these models adequately described the crystallization behavior of the MXD6 nanocomposite at cooling rates below 20 °C/min, but there was a deviation from linear dependence at higher cooling rates. This was attributed to changes of both the free energy and the cooling crystallization function K(T) over the entire crystallization process, as well as possible relaxation effects leading to structural rearrangements. In addition, the activation energy determined using the differential isoconversional method of Friedman was also found to vary, indicating changes in both the free energy and crystallization mechanism. Despite the lack of a reliable theoretical model, the heterogeneous nucleating activity of the MMT nanoparticles was demonstrated and quantified using Dobreva's method (Φ = 0.71), and the crystallization rate for the nanocomposite system was found to be greater than pure MXD6 by up to 79% at 40 °C/min.<br />

Comparison of pQCT parameters between ulna and radius in retired elite gymnasts : the skeletal benefits associated with long-term gymnastics are bone- and site-specific

<b>Objectives:b> To compare the skeletal benefits associated with gymnastics between ulna and radius. <br /><b>Methods: b>19 retired artistic gymnasts, aged 18-36 years, were compared to 24 sedentary women. Bone mineral content (BMC), total and cortical bone area (ToA, CoA), trabecular and cortical volumetric density (TrD, CoD) and cortical thickness (CoTh) were measured by pQCT at the 4% and 66% forearm. <br /><b>Results:b> At the 4% site, BMC and ToA were more than twice greater at the radius than ulna whereas at the 66% site, BMC, ToA, CoA, CoTh and SSIpol were 20 to 51% greater at the ulna than radius in both groups (p&lt;0.0001). At the 4% site, the skeletal benefits in BMC of the retired gymnasts over the non-gymnasts were 1.9 times greater at the radius than ulna (p&lt;0.001), with enlarged bone size at the distal radius only. In contrast, the skeletal benefits at the 66% site were twice greater at the ulna than radius for BMC and CoA (p&lt;0.01).<br /><b>Conclusion:b> Whereas the skeletal benefits associated with long-term gymnastics were greater at the radius than ulna in the distal forearm, the reverse was found in the proximal forearm, suggesting both bones should be analysed when investigating forearm strength.<br />

Properties of a carbon-fibre composite modified by electrospun poly (vinylidene fluoride)

The interlaminar toughening of a carbon-fibre reinforced composite by incorporation of electrospun polyvinylidene fluoride (PVDF) nanofibrous membranes was explored in this work. The nanofibres were electrospun directly onto commercial pre-impregnated carbon fibre materials under optimised conditions and PVDF was found to primarily crystallise in its &beta; phase polymorphic form. There is strong evidence from DMTA analysis to suggest that a partial miscibility between the amorphous phases of the PVDF nanofibres and the epoxy exists. The improved plastic deformation at the crack tip after inclusion of the nanofibres was directly translated to a 57% increase in the mode II interlaminar fracture toughness (in-plane shear failure). Conversely, the fracture toughness in mode I (opening failure) was slightly lower than the reference by approximately 20%, and the results were interpreted from the complex micromechanisms of failure arising from the changes in polymorphism of the PVDF.