Greater rate of decline in maximal aerobic capacity with age in physically active vs. sedentary healthy women

Using a meta-analytic approach, we recently reported that the rate of decline in maximal oxygen uptake (VO2 max) with age in healthy women is greatest in the most physically active and smallest in the least active when expressed in milliliters per kilogram per minute per decade. We tested this hypothesis prospectively under well-controlled laboratory conditions by studying 156 healthy, nonobese women (age 20-75 yr): 84 endurance-trained runners (ET) and 72 sedentary subjects (S). ET were matched across the age range for age-adjusted 10-km running performance. Body mass was positively related with age in S but not in ET. Fat-free mass was not different with age in ET or S. Maximal respiratory exchange ratio and rating of perceived exertion were similar across age in ET and S, suggesting equivalent voluntary maximal efforts. There was a significant but modest decline in running mileage, frequency, and speed with advancing age in ET. VO2 max (ml . kg-1 . min-1) was inversely related to age (P < 0.001) in ET (r = -0.82) and S (r = -0.71) and was higher at any age in ET. Consistent with our meta-analysic findings, the absolute rate of decline in VO2 max was greater in ET (-5.7 ml . kg-1 . min-1 . decade-1) compared with S (-3.2 ml . kg-1 . min-1 . decade-1; P < 0. 01), but the relative (%) rate of decline was similar (-9.7 vs -9. 1%/decade; not significant). The greater absolute rate of decline in VO2 max in ET compared with S was not associated with a greater rate of decline in maximal heart rate (-5.6 vs. -6.2 beats . min-1 . decade-1), nor was it related to training factors. The present cross-sectional findings provide additional evidence that the absolute, but not the relative, rate of decline in maximal aerobic capacity with age may be greater in highly physically active women compared with their sedentary healthy peers. This difference does not appear to be related to age-associated changes in maximal heart rate, body composition, or training factors.     

Calibration of MEMS-based test structures for predicting thermomechanical stress in integrated circuit interconnect structures

This paper uses a rotating-beam-sensor structure to show that the extrinsic stress from the mismatch in expansion coefficient between the aluminum and the silicon substrate dominates over the compressive stress from the sputter growth. Sintering the layers at temperatures above 150/spl deg/C reduces this compressive stress due to the action of creep. Calibration of the rotation of the device has been undertaken by direct comparison to high resolution X-ray-diffraction measurements and these show that the sensor has a resolution better than 2.8 MPa. Furthermore, we have used the sensor to investigate the variation of in-plane stress with the compliance of the intermetal dielectric, by directly comparing sensors fabricated on SiO/sub 2/ and polyimide layers.     

Enhanced foam drainage using parallel inclined channels in a single-stage foam fractionation column

A single-stage vertical foam fractionation column was investigated under continuous steady-state experimental conditions. Using a simple power-law expression to describe the drainage velocity through the foam, and in conjunction with continuity arguments, a theoretical framework was developed to analyse the performance of the vertical column. A reduction in the degrees of freedom in the analysis was achieved by using a fixed feed to gas flux ratio to promote a reasonably constant surfactant recovery. It was then possible to measure the process performance by determining the change in the level of enrichment produced from a change in the gas flux, and corresponding change in the feed flux. For a constant recovery, the enrichment is directly proportional to the volume reduction (defined as the ratio of the feed volume processed to foamate volume produced in a given time). The analysis was found to be consistent with experimental data and demonstrated the need to limit the gas flux, and hence the feed flux, to relatively low values in order to produce satisfactory volume reductions, and in turn achieve high enrichment. To overcome this processing constraint, three parallel inclined channels¹ (PIC) were used to provide an effective increase in the vessel area, and hence facilitate the release of the entrained liquid within the foam. A significant increase in the volume reduction was obtained using the inclined channel arrangement. For the same processing rate, the PIC column achieved up to a 4 fold increase in enrichment compared to the vertical column. A slight decrease in recovery, however, was observed using the PIC column.     

Interference of Non-enzyme Protein in the Reaction of α-Amylase on Amyloses

In a previous communication [1] the assessment of amyloses as potential chromogenic substrates for the assay of α-amylase was described. An α-amylase suscetibility test for amyloses using a highly purified α-amylase from Bacillus subtilis was used. During the course of these investigations commercially available control sera containing α-amylase were used, However, these preparations proved to be highly unsuccessful due to having both low enzyme activity and high level of extraneous protein. Therefore, the difficulties encountered using these preparations are reported in this communication as illustration of a wider principle of superfluous protein in enzyme preparations. In this context it should be noted that industrial preparations of starch degrading enzymes also contain non-enzyme protein and such preparations are used for the production of e. g. glucose and high-fructose syrups.     

Use of gratings and periodic structures as alignment targets on wafer steppers

The use of moiré fringe techniques in microfabrication equipment is reviewed with special emphasis on mask-to-wafer alignment. The alignment strategies and associated detection methods of a number of commercial wafer steppers are described and their limitations are discussed. Potential improvements to be gained by holographic detection of grating targets are pointed out and future applications in a dynamic exposure system are proposed.     

Performance of Micro-fabricated Magnetic Calorimeters Arrays for X-Ray Spectroscopy

We have been developing array technology for fabricating magnetic calorimeters for X-ray astronomy. The magnetization change in each pixel of the paramagnetic sensor material due to the heat input of an absorbed X-ray is sensed by a meander shaped coil. With this geometry it is possible to obtain excellent energy sensitivity, low magnetic cross-talk and large format arrays fabricated on wafers that are separate from the SQUID read-out. A magnetic bias field for each pixel is generated by the use of a persistent current that is stored. We report on the results from our prototype arrays, which are coupled to low noise DC-SQUIDs. The first test results are presented and the sensitivity is compared with calculations.     

Fruit‐based functional foods II: the process for identifying potential ingredients

Developing functional food products requires a structured approach for screening potential ingredients. Using the development of a product with antioxidant properties as a model, eight fruit juice concentrates were screened, including New Zealand fruits. The total phenolic content and the antioxidant capacity, using chemical‐based assays (ferric reducing antioxidant power and oxygen radical absorbance capacity assays), were determined. The potential to protect against oxidative stress in Jurkat cells was also determined. Results indicate that the total phenolic content and antioxidant capacity in chemical‐based assays were strongly correlated. However, the total phenolic content did not dictate the level of protection from oxidative stress in this cell‐based model, suggesting that the type of phenolic compounds present and interactions between them may be important, although the activity of other compounds, such as vitamin C or carotenoids, may also be implicated. This model for screening ingredients may be used to design synergistic combinations of ingredients, and results may provide supportive evidence in the development of functional foods for this and other health targets.