Novel insights into pancreatic β-cell glucolipotoxicity from real-time functional analysis of mitochondrial energy metabolism in INS-1E insulinoma cells.

Work in our lab is supported by the Medical Research Council [New Investigator Research Grant G1100165 to CA] and Plymouth University [PhD studentship to JB] The final version of record is available at http://www.biochemj.org/bj/456/bj4560417.htmHigh circulating glucose and non-esterified (free) fatty acid levels can cause pancreatic β-cell failure. The molecular mechanisms of this β-cell glucolipotoxicity are yet to be established conclusively. In the present paper we report on the involvement of mitochondrial dysfunction in fatty-acid-induced β-cell failure. We have used state-of-the-art extracellular flux technology to functionally probe mitochondrial energy metabolism in intact INS-1E insulinoma cells in real-time. We show that 24-h palmitate exposure at high glucose attenuates the glucose-sensitivity of mitochondrial respiration and lowers coupling efficiency of glucose-stimulated oxidative phosphorylation. These mitochondrial defects coincide with an increased level of ROS (reactive oxygen species), impaired GSIS (glucose-stimulated insulin secretion) and decreased cell viability. Palmitate lowers absolute glucose-stimulated respiration coupled to ATP synthesis, but does not affect mitochondrial proton leak. Palmitate is not toxic when administered at low glucose unless fatty acid β-oxidation is inhibited. Palmitoleate, on the other hand, does not affect mitochondrial respiration, ROS levels, GSIS or cell viability. Although palmitoleate protects against the palmitate-induced ROS increase and cell viability loss, it does not protect against respiratory and insulin secretory defects. We conclude that mitochondrial dysfunction contributes to fatty-acid-induced GSIS impairment, and that glucolipotoxic cell viability and GSIS phenotypes are mechanistically distinct

Transonic flutter study of a wind-tunnel model of an arrow-wing supersonic transport

A 1/20-size, low-speed flutter model of the SCAT-15F complete airplane was tested on cables to simulate a near free-flying condition. Only the model wing and fuselage were flexible. Flutter boundaries were measured for a nominal configuration and a configuration with wing fins removed at Mach numbers M from 0.76 to 1.2. For both configurations, the transonic dip in the wing flutter dynamic pressure q boundary was relatively small and the minimum flutter q occurred near M = 0.92. Removing the wing fins increased the flutter q about 14 percent and changed the flutter mode from symmetric to antisymmetric. Vibration and flutter analyses were made using a finite-element structural representation and subsonic kernel-function aerodynamics. For the nominal configuration, the analysis (using calculated modal data) predicted the experimental flutter q levels within 10 percent but did not predict the correct flutter mode at the higher M. For the configuration without wing fins, the analysis predicted 16 to 36 percent unconservative (higher than experimental) flutter q levels and showed extreme sensitivity to mass representation details that affected wing tip mode shapes. For high subsonic M, empennage aerodynamics had a significant effect on the predicted flutter boundaries of several symmetric modes

Application of vascular aquatic plants for pollution removal, energy and food production in a biological system

Vascular aquatic plants such as water hyacinths (Eichhornia crassipes) (Mart.) Solms and alligator weeds (Alternanthera philoxeroides) (Mart.) Griesb., when utilized in a controlled biological system (including a regular program of harvesting to achieve maximum growth and pollution removal efficiency), may represent a remarkably efficient and inexpensive filtration and disposal system for toxic materials and sewage released into waters near urban and industrial areas. The harvested and processed plant materials are sources of energy, fertilizer, animal feed, and human food. Such a system has industrial, municipal, and agricultural applications

Real-time kinetics and high-resolution melt curves in single-molecule digital LAMP to differentiate and study specific and non-specific amplification

Isothermal amplification assays, such as loop-mediated isothermal amplification (LAMP), show great utility for the development of rapid diagnostics for infectious diseases because they have high sensitivity, pathogen-specificity and potential for implementation at the point of care. However, elimination of non-specific amplification remains a key challenge for the optimization of LAMP assays. Here, using chlamydia DNA as a clinically relevant target and high-throughput sequencing as an analytical tool, we investigate a potential mechanism of non-specific amplification. We then develop a real-time digital LAMP (dLAMP) with high-resolution melting temperature (HRM) analysis and use this single-molecule approach to analyze approximately 1.2 million amplification events. We show that single-molecule HRM provides insight into specific and non-specific amplification in LAMP that are difficult to deduce from bulk measurements. We use real-time dLAMP with HRM to evaluate differences between polymerase enzymes, the impact of assay parameters (e.g. time, rate or florescence intensity), and the effect background human DNA. By differentiating true and false positives, HRM enables determination of the optimal assay and analysis parameters that leads to the lowest limit of detection (LOD) in a digital isothermal amplification assay

Improving child protection : a systematic review of training and procedural interventions

Aim: To synthesise published evidence regarding the effectiveness of training and procedural interventions aimed at improving the identification and management of child abuse and neglect by health professionals. Methods: Systematic review for the period 1994 to 2005 of studies that evaluated child protection training and procedural interventions. Main outcome measures were learning achievement, attitudinal change, and clinical behaviour. Results: Seven papers that examined the effectiveness of procedural interventions and 15 papers that evaluated training programmes met the inclusion criteria. Critical appraisal showed that evaluation of interventions was on the whole poor. It was found that certain procedural interventions (such as the use of checklists and structured forms) can result in improved recording of important clinical information and may also alert clinical staff to the possibility of abuse. While a variety of innovative training programmes were identified, there was an absence of rigorous evaluation of their impact. However a small number of onegroup pre- and post-studies suggest improvements in a range of attitudes necessary for successful engagement in the child protection process. Conclusion: Current evidence supports the use of procedural changes that improve the documentation of suspected child maltreatment and that enhance professional awareness. The lack of an evidence based approach to the implementation of child protection training may restrict the ability of all health professionals to fulfil their role in the child protection process. Formal evaluation of a variety of models for the delivery of this training is urgently needed with subsequent dissemination of results that highlight those found to be most effective

Reducing Residue In Nickel Electroplating Operations

Most commercial nickel electroplating cells use soluble nickel anodes that generate some amount of residue, typically nickel fines and impurities that detach from the bulk during normal operation. Build-up of residue over time leads to failure of the anode and necessitates shutdown and cleaning of the anode assembly before plating can resume. Of specific concern is the increase in plating residue from anode current densities less than 1 A dm-2 because as a consequence of cell design, the anode will often operate at a much lower current density than the cathode. The electrodissolution of carbonyl nickel pellet, a commercial product for the electroplating market has been examined using electrochemical methods, coupled with in situ and ex situ microscopy to better understand the formation of anode residue. Applied potentials above the pitting potential resulted in current densities greater than 3 A dm-2 and pit interiors that were markedly different than those of galvanostatic pits at 0.4 A dm-2. Current transients for potentiostatic pulses above the pitting potential were analyzed and the transition times for stages of pit growth were identified. A potential pulse sequence was then used to execute highly controlled cycles of pit nucleation, growth and repassivation that resulted in anode surface morphologies different than those treated galvanostatically. Potential pulse dissolution with a pulse time of 50 ms and 45% duty cycle gave a current density of 0.33 A dm-2 and resulted in more than a six-fold decrease in anode residue when compared to galvanostatic dissolution