DETERMINATION OF MOISTURE AND FATTY SUBSTANCES CONTENTS OF SOLID ADJUNCTS

Two new methods—moisture at 130–133°C and fatty substances extracted by petroleum ether—were collaboratively tested by 14 laboratories (EBC and IOB Analysis Committee members and other laboratories). For moisture the following values were obtained in the range 12 to 15% m/m, repeatability=0.13% m/m and reproducibility=0.60% m/m. For fatty substances in the range 0.3 to 0.9% m/m the following values were obtained: repeatability=(0.06 m+0.02)% m/m and reproducibility=(0.14 m+0.09)% m/m. Both methods were accepted and will replace methods 6.1 and 6.4 respectively in Analytica EBC. The method for Fatty Substances will replace IoB methods 4.1.3 and 4.2.3. These modifications will become operative on 1 September, 1996.     

Effects of chytrid and carbaryl exposure on survival, growth and skin peptide defenses in foothill yellow-legged frogs

Environmental contaminants and disease may synergistically contribute to amphibian population declines. Sub-lethal levels of contaminants can suppress amphibian immune defenses and, thereby, may facilitate disease outbreaks. We conducted laboratory experiments on newly metamorphosed foothill yellow-legged frogs (Rana boylii) to determine whether sublethal exposure to the pesticide carbaryl would increase susceptibility to the pathogenic chytrid fungus Batrachochytrium dendrobatidis that is widely associated with amphibian declines. We examined the effect of carbaryl alone, chytrid alone, and interactions of the two on individual survival, growth, and antimicrobial skin defenses. We found no effect of chytrid, carbaryl, or their interaction on survival. However, chytrid infection reduced growth by approximately one-half. This is the first report of suppressed growth in post-metamorphic amphibians due to infection with chytrid. Rana boylii skin peptides strongly inhibited chytrid growth in vitro, which may explain why chytrid exposure did not result in significant mortality. Skin peptide defenses were significantly reduced after exposure to carbaryl suggesting that pesticides may inhibit this innate immune defense and increase susceptibility to disease.     

Modelling of aircraft manufacturing cost at the concept stage

The work presented is concerned with the estimation of manufacturing cost at the concept design stage, when little technical information is readily available. The work focuses on the nose cowl sections of a wide range of engine nacelles built at Bombardier Aerospace Shorts of Belfast. A core methodology is presented that: defines manufacturing cost elements that are prominent; utilises technical parameters that are highly influential in generating those costs; establishes the linkage between these two; and builds the associated cost estimating relations into models. The methodology is readily adapted to deal with both the early and more mature conceptual design phases, which thereby highlights the generic, flexible and fundamental nature of the method. The early concept cost model simplifies cost as a cumulative element that can be estimated using higher level complexity ratings, while the mature concept cost model breaks manufacturing cost down into a number of constituents that are each driven by their own specific drivers. Both methodologies have an average error of less that ten percent when correlated with actual findings, thus achieving an acceptable level of accuracy. By way of validity and application, the research is firmly based on industrial case studies and practice and addresses the integration of design and manufacture through cost. The main contribution of the paper is the cost modelling methodology. The elemental modelling of the cost breakdown structure through materials, part fabrication, assembly and their associated drivers is relevant to the analytical design procedure, as it utilises design definition and complexity that is understood by engineers.     

Efficacy of sulfadoxine-pyrimethamine for prevention of placental malaria in an area of Kenya with a high prevalence of malaria and human immunodeficiency virus infection

Our current knowledge of mammalian forebrain development is meagre. The comparatively few relevant anatomical landmarks are, however, being supplemented by gene expression studies which are able to identify subsets of anatomical structures. We previously described cloning, subchromosomal localization and preliminary structural characterization of the human WNT8B gene, the first mammalian Wnt8b gene to be reported. Wnt genes encode intercellular signalling molecules which play a variety of critical roles in early development, including, in several cases, a presumed role in brain development. In the current report we present the full-length cDNA sequence and genomic organization of the human Wnt8b gene and report studies of expression of the Wnt8b gene in human and mouse embryos. The human and mouse expression patterns appeared identical and were restricted to the developing brain, with the great majority of expression being found in the developing forebrain. In the latter case expression was confined to the germinative neuroepithelium of three sharply delimited regions: the dorsomedial wall of the telencephalic ventricles (which includes the developing hippocampus), a discrete region of the dorsal thalamus and the mammillary and retromammillary regions of the posterior hypothalamus. Expression in the developing hippocampus may suggest a role for WNT8B in patterning of this region and subchromosomal localization of the human gene to 10q24 may suggest it as a candidate gene for partial epilepsy in families where the disease has been linked to markers in this region.     

Long-term effects of vincristine on the peripheral nervous system

A total of 317 mandibular fracture patients treated and diagnosed at the Oulu University Hospital and at the Department of Oral and Maxillofacial Surgery, University of Oulu, Finland, between 1981 and 1990 were analyzed from patient files and radiographs. The mean number of mandibular fracture patients per year was 31.7 (range 21 and 45) and the mean age of the patients 31.3 years (range 4-78 years). The female:male ratio was 1:3.1. There seemed to be a tendency for decrease in the proportion of violence and traffic accidents as causes of mandibular fractures toward the end of the period concerned, reflecting partly the influence of mandatory use of safety belts and partly that the hospital in the northernmost part of Finland, where the consumption of alcohol is higher than in the province of Oulu, could treat all mandibular fractures itself during the last year studied thus decreasing the injuries caused by violence at the Oulu University Hospital. It was also noted that fewer fractures were caused at weekends than on weekdays during the latter years of the decade and that the proportion of male victims decreased except for the last year examined, 1990.     

An Investigation of the Failure Mechanisms of a Polymer Matrix Composite Crew Oar

Journal of Failure Analysis and Prevention - Rowing, or crew, is a constantly evolving sport with an impressive history of equipment advancements, including the use of advanced polymer matrix...     

Analytic study of foaming agents in imported beers

The French consumer expects a natural high-quality drink. It was therefore of interest to ascertain the quality of imported beers (they reached 2,440,000 hl in 1976, or 9.8 f. 100 of total sales) as well as how far their composition complies with present French legislation. Fifteen imported bottled beers were analyzed, from the following countries: West Germany, England, Belgium, Denmark, Luxemburg and the Netherlands. Attempts were first of all made to detect the presence in these beers of iron and cobalt, since both metals are recognized froth-improving agents. The search for cobalt produced negative results for all the beers. On the other hand we found that five of the 15 samples examined were questionable for their iron content (0.56--1.52 mg/l). We than looked for alginates in these imported beers, using a method comprising the following sequence of operations: concentration of the beer, dextrine hydrolysis, alginate precipitation at pH 5 by calcium chloride, treatment of the heated preparation with sodium hexametaphosphate, and colorimetric measurement at 670 nm with a reagent comprising orcinol, ferric sulfate and hydrochloric acid. In most of the 15 imported beers studied, the presence of alginates (up to 16.5 mg/l) was indisputable. The French consumer therefore has a right to expect the composition of foreign beers to comply with the French food laws, especially as regards the absence of frothing agents.     

Numerical simulation of crystallization in high density polyethylene extrudates

Three‐dimensional numerical simulation of solidification of high density polyethylene (HDPE) in a parallelepiped shaped extrudate is accomplished using a cell model for spherulite growth on a microscopic level under quiescent conditions and coupled with an enthalpy based heat transfer equation on the macroscopic level. The parallelepiped is cooled from the melting point of HDPE by a stream of air blown across it. When the thickness of the extrudate is of the order of microns, the distribution of the degree of crystallinity and temperature is uniform, and the lumped system formulation to model crystallization and heat flow is applicable. But significant variations inside the extrudate are observed when the thicknesses are of the order of millimeters and centimeters. The non‐dimensional Deborah and Biot numbers are shown to be important in the applicability of the formulation. The effects of air speed and ambient temperature on the crystallization process are also studied. It is observed that both (1) an increase in the air speed and (2) a decrease in the ambient temperature increase the rate of crystallization in the parallelepiped. The former has much greater effect than the latter in changing the average convective heat transfer coefficient. As a result, increasing the air speed results in much larger spherulites compared to reducing the ambient temperature. Decrease of temperatures in the extrudate during the either cooling processes is observed to be non‐monotonic owing to the release of the latent heat during crystallization. Introducing a constant temperature (melting point of HDPE) at a cross section of the extrudate changes the distribution of relative crystallinity and temperature in the extrudate significantly: the temperature gradient becomes much higher along the extrudate axis, and the material near the cross section never solidifies. Also, the extrudate behaves more like a fin as the variations in the thickness direction become insignificant.     

Evaluation of a fluorodensitometric method for analysis of ergosterol as a fungal marker in compound feeds.

Ergosterol is the principal sterol of fungi and plays an essential role as a component of the cell membrane and other cell constituents. This molecule is considered a good marker of fungal contamination in foods and feeds. This paper reports a rapid and sensitive method to test ergosterol content in compound feeds based on fluorodensitometry after thin-layer chromatography (TLC) separation. This method involves a thermal treatment of TLC plates that leads to the formation of a highly fluorescent ergosterol derivative. Such a dosage allows ergosterol testing in any naturally contaminated samples (limit of detection: 1 ppm of ergosterol) and gives results in close agreement with high-pressure liquid chromatography determination. Moreover, values obtained on mixed feeds for animals at different steps of fungal contamination are linked to quantitative development of storage fungi, evaluated by mycological technique, reinforcing the interest of a rapid method for measuring this fungal marker.     

Electricity generation from renewable energy : The French experience

Besides its traditional and large scale involvement in hydro power, EDF has recently taken a significant interest in “new” renewable energy sources. The present paper describes the reasons and the field of application of this interest.