High incidence of cystic fibrosis on the Faroe Islands: a molecular and genealogical study

We have studied the genetics of cystic fibrosis (CF) in The Faroe Islands. Based on the number of affected children born during the period 1954-1993, the incidence of CF at birth is 1:1775, which is more than twice the incidence in the rest of Denmark. We have tested all known CF patients and/or their parents for the presence of delta F508 and found it to be the only CF mutation in this population. Based on testing 881 unrelated control individuals, the carrier frequency was estimated to be 1:24, given a calculated incidence of 1:2300. Genealogical studies enabled us to trace several of the families over seven generations. Haplotype investigations within the families suggest that delta F508 was introduced by two founders, probably from the Celtic population in Brittany, Ireland, Wales or the North West of Scotland.     

The resistance of 20Cr/25Ni steels to carbon deposition. III. Cold work and selective pre-oxidation

Specimens of annealed 20 Cr/25Ni/Nb, selectively pre-oxidised 20Cr/25Ni/Nb, cold worked 20Cr/25Ni/Nb and TiN-strengthened 20Cr-25Ni steels have been exposed to a 75% CO/CO₂ gas atmosphere for periods up to 2000 hrs at 923 K (650°C). Whereas the cold-worked and TiN-strengthened steels show high resistance to this environment, the annealed Nb-stabilised alloy exhibited large amounts of carbon deposition. Associated with these were extensive regions of oxide pitting and gross carburisation of the substrate. By contrast, the selectively preoxidised specimens suffered much less deposition and no evidence for carburisation was found. It was also shown that small quantities of defects in the original preoxidised layer increased the propensity for deposition but did not result in local carburisation.     

212 transmission electron microscopy applied to phase transformations in ball bearings

$\text{2}\text{1}\text{2}$D transmission electron microscopy has been applied to rolling contact-fatigued ball bearings. The $\text{2}\text{1}\text{2}$D technique implies that correlations between image features and the object lattice structure are transformed to a stereoscopic effect, using defocused dark-field image pairs. During contact fatigue, the martensite matrix may decay and be transformed to new phases. Particularly, a carbon-enriched phase has been studied. The findings indicate areas of probable nucleation sites and areas being dilated due to internal stresses. The phase is constituted of a lattice structure with minor and regular variations in the g-vector, involving vector orientation and magnitude.     

Dental caries, tooth trauma, malocclusion, fluoride usage, toothbrushing and dietary habits in 4-year-old Swedish children: changes between 1967 and 1992

The dental health of 4-year-old children in the city of Ume?, northern Sweden, has been followed in cross-sectional studies conducted in 1967, 1971, 1976, 1980, 1987 and 1992. Similar methods and criteria were used. Dental caries and background factors (fluoride usage, toothbrushing frequency and diet) were recorded. In 1971, 1987 and 1992 signs of tooth trauma and presence of malocclusion were also recorded, the latter also in 1976. The present paper summarizes the results of these studies. Between 1967 and 1992 the mean dmfs values declined from 7-8 to 1-8. The decline was greatest between 1967 and 1980 and then levelled off. Toothbrushing frequency was similar over the years, but parental help with brushing was more common in the more recent studies. The use of fluoride toothpaste increased. About 30% of the children had experienced tooth trauma. A unilateral crossbite was recorded in 18% and 16% of the children in 1971 and 1992, respectively, and an anterior open bite in about 35% and 41%, respectively; both types of malocclusion were related to a dummy- or finger-sucking habit.     

Building thermal analyses: What the industry needs: The Architect''s perspective

Drawing on experience as a practitioner, the author argues that a static need definition is necessarily inferior to a dynamic need definition attained by a feed-back and feed-forward procedure built on general systems theory. The designer's approach, working from the whole towards the detail, is contrasted with the way analytical models are typically structured. Recent advances, problems and future work are identified.