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The objectives of this study were to investigate the generation of β -lactoglobulin fragment (142–148) ( β -LG f(142–148) during the hydrolysis of whey proteins, and the in vitro stability of this fragment upon incubation with gastrointestinal and serum proteinases and peptidases. An enzyme immunoassay (EIA) protocol was developed for the quantification of β -LG f(142–148) in whey protein hydrolysates and in human blood serum. The minimum detection limit was 3ng/mL. The level of the peptide in whey protein hydrolysates was influenced by the degree of hydrolysis (DH). As expected, highest levels of this peptide were found in hydrolysates generated with trypsin. Sequential incubation of hydrolysates at different DH values with pepsin and Corolase PP, to simulate gastrointestinal digestion, generally resulted in the degradation of β -LG f(142–148) as determined by EIA. Reversed-phase HPLC and angiotensin-I-converting enzyme (ACE) activity assays demonstrated that synthetic β -LG f(142–148) was rapidly degraded upon incubation with human serum. Furthermore, β -LG f(142–148) could not be detected by EIA in the sera of 2 human volunteers following its oral ingestion or in sera from these volunteers subsequently spiked with β -LG f(142–148). These in vitro results indicate that β -LG f(142–148) is probably not sufficiently stable to gastrointestinal and serum proteinases and peptidases to act as an hypotensive agent in humans following oral ingestion. The in vitro methodology described herein has general application in evaluating the hypotensive potential of food protein-derived ACE inhibitory peptides.

MCBEND is an established Monte Carlo code in the fields of shielding, dosimetry and general radiation transport. The development of the code is continuing within a partnership between Serco Assurance and BNFL and this paper reviews the current status of the code and describes some recent developments, including a point energy adjoint facility and automatic generation of a splitting mesh for variance reduction.

The potential of companion crops to serve as diversionary hosts for ovipositing Helicoverpa spp. moths in chickpea cropping systems was evaluated in a field experiment. Patterns of egg distribution by Helicoverpa spp. within paired combinations of chickpea and each of six companion crop species were documented in a split-plot design sampled four times during the 1999 winter growing season. Chickpea was attractive to ovipositing Helicoverpa moths from as early as 14 days after planting and throughout the experimental period. The companion crop species varied in relative attractiveness to ovipositing moths but none was able to effectively divert Helicoverpa egg pressure away from chickpea for the duration of the experiment. Of all Helicoverpa spp. larvae recorded from all samples and crop combinations, 98.3% were found on chickpea. A marked aggregative oviposition behaviour of Helicoverpa spp. on tall weeds growing through the chickpea canopy was recorded. The relevance of observed patterns of host selection and inferred moth behaviour to management of Helicoverpa populations on chickpea are discussed.

For pt. I see ibid., vol.42, no.2-4, p.1684-1697 (1994). Nonlinear processing significantly enhances detector performance in nongaussian noise relative to that of linear detectors. Several nonparametric detection schemes for impulsive noise channels are formulated using the nonparametric probability density estimators developed in Part I. The likelihood ratio test and the small-signal (locally optimum) nonlinearity provide the basis for the formulation of these nonparametric detection schemes. Several modifications to these basic strategies are used to compensate for inaccuracies in the density estimates. In particular, for the problem of detecting a known signal in impulsive noise, two modifications to the standard likelihood ratio test are considered: the first is adapted from robust statistics, whereas the second, the "L/sub 1/-error-based" detector is specifically formulated for use with density estimates. Both schemes are found to perform close to the optimum likelihood ratio detector for a wide variety of impulsive noise densities. From the merits of these two tests, a new detection scheme that approximates the locally optimum nonlinearity is then developed. This detector, which uses the nonparametric density estimators developed in Part I, is shown to perform very well for the wide variety of impulsive and heavy tailed densities considered in the study. This nonparametric-density-estimate-based detector is also shown to outperform more conventional nonparametric detectors in impulsive noise. >

A kernel-based density estimator for positive random variables is proposed and analyzed. In particular, a nonparametric estimator is developed which takes advantage of the fact that positive random variables can be represented as the norms of random vectors. By appropriately choosing the dimension of the assumed vector space, the estimator can be structured to exploit a priori knowledge about the density to be estimated. The asymptotic properties (e.g., pointwise and L/sub 1/-consistency) of this density estimator are investigated and found to be similar to the desirable features of the standard kernel estimator. An upper bound on the expected value of the L/sub 1/ error is also derived which provides insight into the behavior of the estimator. Upon using this upper bound, the optimal form for the estimator (i.e., the kernel function, the smoothing factor, etc.) is selected via a minimax strategy. In addition, this upper bound is used to compare the asymptotic performance of the proposed estimator to that of the standard kernel estimator and to boundary-corrected kernel estimators. Numerical examples illustrate that the proposed scheme outperforms the standard and boundary-corrected estimators for a variety of density types. >

The IRDF2002 dosimetry cross-section data are processed into very fine energy groups and added to the detector response library for the Monte Carlo code MCBEND. The IRDF2002 covariances are processed into broad groups to form a MCBEND detector covariance library. A number of benchmark experiments are analysed using MCBEND with both IRDF2002 and IRDF90 data and the results compared. Uncertainties due to material and detector cross-sections are calculated automatically. The results demonstrate that the IRDF2002 115 In(n,n') 115m In dosimetry cross-sections give improved agreement between calculation and measurement in an iron benchmark and that use of IRDF2002 data allows straightforward, explicit and accurate calculation of single resonance detector reaction-rates, e.g. 197 Au(n,γ) 198 Au.

An understanding of data acquisition and processing in magnetic resonance imaging (MRI) facilitates subsequent manipulation and analysis of the resultant images. Unlike other medical imaging modalities, MRI is not well described in terms of the transmission and reception of a propagating wave since the wavelength of the radiofrequency signals involved is on the order of meters. Rather, MRI exploits the fact that the magnetization vectors associated with certain atoms (notably protons in water) will, when placed in a strong magnetic field, oscillate at a frequency proportional to that field. By spatially varying the magnetic field, position is mapped by the frequency and phase of the field effects caused by the oscillating magnetization vectors at each location. The data acquisition associated with this spatial mapping can be described as temporally scanning the Fourier or spatial frequency domain of the volume of interest. Image reconstruction is achieved by an inverse Fourier transform of the received signal. The Fourier representation of the imaging process is developed from an overview of the physics underlying MRI signal behaviour. Under this formalism, trade-offs in acquisition time, resolution, and field-of-view as well as image degradation associated with noise are addressed. Finally, the ability in MRI to manipulate soft tissue contrast over a wide range of independent parameters is outlined. >

The study is concerned with the development of effective nonparametric probability density estimators and detectors for impulsive noise channels. Two estimators are proposed: the first is particular to envelope densities while the second is designed for instantaneous amplitude densities. >

Purpose Aortic valve opening (AVO) during left ventricular assist device (LVAD) support has important clinical implications in preventing thrombosis and leaflet fusion causing chronic regurgitation. Assessment of AVO has become part of routine LVAD care. Traditionally, this has been done with transthoracic echocardiography (TTE) but that technology is costly and not always readily available, especially as patients are increasingly released back to their communities. This study investigates the use of LVAD power waveform analysis as a faster and inexpensive method of evaluating AVO in LVAD patients. Methods and Materials Waveforms were collected from HeartMate II LVAD controllers and saved in The Artificial Heart Program database. Waveforms were then matched with corresponding TTE reports to determine AV status. A LabView program was used to filter and analyze these power waveforms and output characteristics of each wave. These characteristics were then stratified into AV opened or AV closed groups. Averages of parameters for each group were taken and compared using a two-tailed Student’s t-test. Results 492 AV closed waveforms were obtained from 39 patients and 168 AV opened waveforms were obtained from 19 patients. Patients with open AV are shown to have higher average wave amplitudes, and took a larger percentage of time to reach max amplitude as shown by the skewness which is a measure of wave asymmetry. Conclusions We describe an innovative and inexpensive method of detecting significant differences between open and closed AV. Further study is needed to create and validate a user interface in LabView to input an unknown waveform and be able to predict AVO within a reliable accuracy level. AV Closed (n=492) AV Open (n=168) Waveform Characteristics μ ± μ ± p-values Baseline Current (mA) 303 77 305 83 0.85 Amplitude (mA) 139 37 160 50 Skewness 0.07 0.41 -0.08 0.44 Table 1 μ: mean, ±: standard deviation

The Pacific Northwest Laboratory (PNL) prepared this report under contract to the Bonneville Power Administration (Bonneville), as part of the Resource Supply Expansion Project (RSEP). RSEP is a regional program instituted by Bonneville to expand conservation and renewable generation options available to resource planners and utilities. Resource alternatives are increased by RSEP through demonstration projects designed in a collaborative process that targets specific barriers to resource development including institutional, market, and reliability barriers. RSEP was launched with several projects that were designed and implemented quickly in 1992 to lay a foundation for future collaboration. The purpose of this report is to introduce the goal and structure of RSEP and to describe the so-called ``Quick Start`` RSEP projects in Phase One of RSEP. This description includes a preliminary estimate of the energy savings and/or other expected impacts of RSEP projects funded in FY 1992 and 1993. Similar estimates are also included for Bonneville projects to confirm wind and geothermal generation potential. Bonneville`s Geothermal Confirmation Agenda preceded implementation of RSEP, although it has a similar objective and collaborative approach.

This report describes a comprehensive customer database compiled by the Pacific Northwest Laboratory (PNL) to assist with analyses conducted as part of the Western Area Power Administration Energy Planning and Management Program Environmental Impact Statement (EIS). The database was used by PNL as a tool to help select a sample of Western customers for potential participation in the Organizational Impacts Analysis case studies, and was used as part of the Utility Impact Analysis to identify sources and costs of auxiliary power. Secondary information sources were used predominantly to compile one year of system related information on the Western customers (over 600) included in the database. This information was useful for its intended purposes; however, year-to-year information may not be consistent across utilities and not all information was available for each utility.

A monolayer of bismuth sulphide was formed anodically on a hanging drop electrode of bismuth amalgam in aqueous NaHCO3 solution containing HS− at 20°C. Potential sweep experiments showed a monolayer current peak with a charge density of 430 μC cm−2, in close agreement with the value predicted from the (010) plane of orthorhombic bismuth sulphide, with chains of (Bi4S6)n on the electrode surface. The monolayer peaks of HgS were suppressed by prior formation of the Bi2S3 monolayer, and a mixed film of Bi2S3 and Bi2O3 formed at a higher overpotential. Galvanostatic transients gave a small nucleation peak, followed by growth at a constant overpotential until the monolayer was complete. Potentiostatic transients showed an asymmetric current peak indicating that the mechanism of monolayer formation involves instantaneous nucleation followed by expansion and overlap of two-dimensional centres.

Heat transfer is a major problem in the design of lighting fittings: the large amounts of heat produced by light sources can cause dangerous and expensive damage to a fitting. A mathematical model which could predict fitting temperatures would be useful in such design processes. Simple models of the coupled heat transfer in a typical lighting fitting are developed from models of the individual heat transfer processes involved. The individual processes are conduction, natural convection and radiation through a nonparticipating medium (air). The coupling is seen to be through the boundary conditions at the shade of the fitting. The models are used to predict the temperatures at various points on the shade of the fitting for two ‘general lighting service’ (GLS) filament lamps. They are shown to be in reasonable agreement with experiment. Possible improvements to the models so that fluxes as well as temperatures can be accurately modelled are suggested. The methods developed for modelling the coupled heat transfer in the lighting fitting are also applicable to other industrial and environmental heat transfer problems such as the cooling of sheet steel in a steel mill or the interaction of solar radiation with the earth's surface and atmosphere.

This paper examines the recent acquisition by Newcastle Polytechnic Library of a computer aided circulation control system. Using the Cost Benefit Analysis methodology (CBA), the costs and benefits of the new system are compared with the previous manual system, particular attention being given to the valuation of students' time. While the CBA approach has many critics, it is basically just an application of traditional economics, i.e. a study of the allocation of resources modified to take account of non‐marketed costs and benefits. As such, it can be a useful guide to policymakers through the identification and evaluation of ‘external’ costs and benefits of alternative projects. External effects which the organisation's accounting methods might otherwise ignore. The study, though subject to errors of omission and misinterpretation (which are inevitable given the complexity of the project and the limited resources available to the analyst), showed that the resource costs of the new installation exceeded the benefits by £33,000 — discounted over a projected life of five years. The major factors influencing this conclusion were: the high cost of ‘in house’ computer programming, and the relatively small saving of user time. A more sophisticated computer with the capacity to hold ‘online’ information on the current state of the book stock could have had a significant impact on the time taken to borrow an item. This would have increased the benefits to users (and possibly encouraged a rise in demand) which may have been sufficient to offset the additional capital costs.

The available results for tests on over 200 surfactants in nine short-term genotoxicity assay systems were reviewed. These tests included the Salmonella/microsome mutation assay, bacterial DNA repair tests, mitotic recombination in Saccharomyces cerevisiae, the mouse lymphoma cell-mutation assay, unscheduled DNA synthesis and sister chromatid exchange assays in mammalian cells, mammalian chromosome damage tests in vitro and in vivo, the dominant lethal test in rodents, and mammalian cell-transformation tests. The collected data cover all four major classes of surfactants: anionic, cationic, nonionic and amphoteric. The results of these genotoxicity tests were overwhelmingly negative. Although there were occasional positive results in bacterial or cell-transformation systems, the testing performed to date indicates that surfactants have negligible potential to cause genetic damage. The available data also indicate that none of the assays were incompatible with testing surfactants for genotoxicity.

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The following cell was used to determine the standard free energy of formation of Bi3+ (aq): (-)Pt, H2 HClO4, Bi(ClO4)3 Bi, Hg (sat.) (+) The saturated amalgam contained bismuth at the same chemical potential as the pure metal, but gave a more reproducible and rapidly reversible potential. Measurements were made at various perchloric acid concentrations between 0.6 and 4.0 M which served to repress hydrolysis and provided a constant ionic medium. At each perchloric acid concentration the Nernst equation was obeyed since [Bi3+] was small relative to the total ionic concentration, and thus activity coefficients were constant For 1 M HClO4. E = 0.2921 + RT/3F ln [B3+]/[H+]3 V, 25°C. It was found that the apparent standard electrode potential E′0 varied only slightly as the total ionic concentration C was changed. E′0 = 0.2928–0.00072 C ± 0.0005 V. Hence the standard electrode potential at infinite dilution is E0 = 0.2928 ± 0.0005 V, and the activity coefficient factor fBi3 + /f3H+ is close to unity in 0–4 M HClO4. δG0f, Bi3+(aq) = +20.26 kcal mole-1 and the free energy of hydration, Bi3+(g) → Bi3+(aq), δG0h = —1166 kcal mole-1 Hydration free energies of metallic cations appear to correlate with ionization potentials.

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