Jim McLaughlin

Exercise and postprandial lipaemia: effects on peripheral vascular function, oxidative stress and gastrointestinal transit

Postprandial lipaemia may lead to an increase in oxidative stress, inducing endothelial dysfunction. Exercise can slow gastric emptying rates, moderating postprandial lipaemia. The purpose of this study was to determine if moderate exercise, prior to fat ingestion, influences gastrointestinal transit, lipaemia, oxidative stress and arterial wall function. Eight apparently healthy males (age 23.6 ± 2.8 yrs; height 181.4 ± 8.1 cm; weight 83.4 ± 16.2 kg; all data mean ± SD) participated in the randomised, crossover design, where (i) subjects ingested a high-fat meal alone (control), and (ii) ingested a high-fat meal, preceded by 1 h of moderate exercise. Pulse Wave Velocity (PWV) was examined at baseline, post-exercise, and in the postprandial period. Gastric emptying was measured using the 13C-octanoic acid breath test. Measures of venous blood were obtained prior to and following exercise and at 2, 4 and 6 hours post-ingestion. PWV increased (6.5 ± 1.9 m/sec) at 2 (8.9 ± 1.7 m/sec) and 4 hrs (9.0 ± 1.6 m/sec) post-ingestion in the control group (time × group interaction, P < 0.05). PWV was increased at 2 hrs post-ingestion in the control compared to the exercise trial; 8.9 ± 1.7 vs. 6.2 ± 1.5 m/sec (time × group interaction, P < 0.05). Lipid hydroperoxides increased over time (pooled exercise and control data, P < 0.05). Serum triacylglycerols were elevated postprandially (pooled exercise and control data, P < 0.05). There were no changes in gastric emptying, cholesterol, or C-reactive protein levels. These data suggest that acute exercise prior to the consumption of a high-fat meal has the potential to reduce vascular impairments.

A study of microstructural and electrochemical properties of ultra-thin DLC coatings on AlTiC substrates deposited using the ion beam technique

Microstructural and electrochemical characterization of diamond like carbon (DLC) ion beam-deposited on AlTiC (70 wt% Al2O3 + 30 wt% TiC) substrate has been carried out. Tapping mode atomic force microscopy (AFM) imaging showed that the island-like topography of DLC-coated substrates is similar to the un-coated one, indicating the uniform coverage of DLC without visible pinholes. Confocal micro-Raman analysis demonstrated that the total Raman intensity, as well as the I-D/I-G ratio, increases with the coating thickness. Electrochemical impedance spectra showed that with the increasing DLC coating thickness, a transition from one-time constant response to two-time constant response occurred when the coating thickness equals 5 nm (IS2), indicating the existence of micro-defects in the coatings which are invisible for AFM. More detailed analysis using the equivalent circuit model revealed that the charge transfer resistance (R-ct) at electrolyte/substrate interface and the resistance (R-p) related to DLC coatings increase significantly with the coating thickness, while the double-layer capacitance (C-dl) and the capacitance (C-co) of DLC coatings decrease dramatically. All these phenomena can be interpreted in terms of the evolution of the subsurface diamondlike phase (sp(3)-bond) and the reduction of micro-defects in the DLC coatings with the growing film. As a result, an increase in the corrosion potential (E-c) with the DLC coating thickness was also detected using the Tafel technique. In consequence, the DLC coatings can improve significantly the anti-corrosion properties of AlTiC substrates when the coating thickness is more than a few tens of nanometres

Solid-state ion-selective electrode arrays

Variable pressure scanning electron microscopy is demonstrated to be a powerful method for directly studying swelling processes occurring during conditioning of PVC-membrane ion-selective electrodes containing a salt-doped hydrogel layer between the PVC and the internal Ag/AgCl reference electrode. Using an in-house developed virtual instrument interface and a portable PC fitted with a PCMCIA data acquisition card, it is relatively easy to adapt arrays manufactured for blood-gas analysis for other applications which involve the determination of mixtures of inorganic ions. The simultaneous analysis of sodium and chloride over concentration ranges associated with the diagnosis of cystic fibrosis (CF) in sweat is demonstrated as an example.

Biomedical Sensors for Ambient Assisted Living

The percentage of the population classified as being elderly has been predicted to increase dramatically in size over the next 30-40 years. Figures produced by the World Health Organisation (WHO) anticipate an increase from around 600 million in the year 2000 to close to 2 billion by the year 20501. By 2050, 22% of the world’s population will be over 602 in Europe it will be over 30%3. In addition, according to the WHO, approximately 10% of the population experience some form of disability. Already 21% of people above the age of 50 have severe vision, hearing and/or mobility problems.

Acute exercise and impaired glucose tolerance in obese humans

BACKGROUND Individuals with impaired glucose tolerance (IGT) have a greater risk of developing diabetes and cardiovascular disease compared with those with normal glycemic control. The aim of this study was to examine the effects of acute aerobic exercise on glycemia, regional arterial stiffness, and oxidative stress in obese subjects with IGT. DESIGN Twelve obese subjects (7 men and 5 women; 48.0±9.4 years; body mass index 32.4±7.0kg/m(2)) with IGT participated in a 30-minute bout of walking at 65% of maximum predicted heart rate. Pulse wave velocity (PWV, for determination of arterial stiffness) and blood pressure were examined before and after exercise, whereas venous blood samples were drawn for the determination of glucose, blood lipids, and indices of oxidative stress and inflammation (lipid hydroperoxides; superoxide dismutase; high-sensitivity C-reactive protein). RESULTS After exercise PWV (9.1±1.2m/s vs. 8.6±1.0m/s), glucose (5.7±0.6 mmol·L(-1) vs. 5.4±0.6 mmol·L(-1)), and diastolic blood pressure (94±14mm Hg vs. 86±13mm Hg) decreased, respectively (P < .05). A correlation was observed between PWV and glucose (r=0.544, P < .05). There were no changes in lipid hydroperoxides, superoxide dismutase, high-sensitivity C-reactive protein, or blood lipids (P > .05). CONCLUSIONS These findings suggest that acute aerobic exercise can reduce regional arterial stiffness in obese subjects with IGT by possibly improving glucose metabolism, independent of changes in oxidative stress.

An Investigation into the Electrical Properties of Doped Barium Titanate Using Electrical Impedance Spectroscopy (EIS)

Barium titanate has been doped with rare earth oxides (erbium, holmium, gadolinium and yttrium), in an attempt to understand the effect upon the reliability of the dielectric material for multilayer capacitor applications. The morphology of the samples used was characterized using scanning electron microscopy (SEM). It is suggested that incorporation of rare earth ions into the BaTiO3 is as a result of ionic radius, resulting in varying grain growth and electrical properties. The change in reliability and electrical properties of the capacitor can be attributed to the overall distribution of rare earth oxides and their occupation site within the dielectric.

An investigation into the electrical properties of doped barium titanate using EIS

Barium titanate has been doped with rare earth oxides (Erbium, Holmium, Gadolinium and Yttrium) in an attempt to understand the effect on the reliability of the dielectric material for multilayer capacitor applications. The morphology of the samples used was characterized using scanning electron microscopy (SEM) with EDAX used to confirm the presence of each rare earth ions. It is suggested that incorporation of rare earth ions into the BaTiO3 is as a result of ionic radius, resulting in varying grain growth and electrical properties. The change in reliability and electrical properties of the capacitor can be attributed to overall distribution of rare earth oxides and their occupation site within the dielectric.