The presence of interfaces and geometrical confinement can have a strong influence on the structure and morphology of thin films of semicrystalline polymers. Using surface-sensitive grazing incidence wide angle X-ray scattering and atomic force microscopy to investigate the vertical structure of thin films of poly(3-hexylthiophene) crystallized from the melt, we show that highly oriented crystallites are induced at the air/polymer interface and not as sometimes assumed at the interface to the substrate. These crystallites are oriented with their crystallographic a-axis perpendicular to the plane of the film. While the corresponding orientation dominates in thinner films, for sufficiently thick films (>60 nm) a layer containing unoriented crystals is present below the surface layer. Due to the anisotropic charge transport properties, the observed effects are expected to be of special relevance for potential applications of semiconductor polymers in the field of organic photovoltaics for which vertical transport in thicker films plays an important role.

Alongitudinal study of growth and physical fitness of twins and their parents was designed in 1985. The major aims of this Leuven Longitudinal Twin Study were to quantify the genetic and environmental determination of (1) somatic characteristics, biological maturation and physical performance characteristics during the growth process, (2) the growth and developmental patterns, and (3) the covariation in somatic and performance characteristics.

Alkalizing beverages are highly effective in preventing the recurrence of calcium oxalate (Ox), uric acid and cystine lithiasis. The aim of the present study was to evaluate the influence of grapefruit-juice and apple-juice consumption on the excretion of urinary variables and the risk of crystallization in comparison with orange juice. All investigations were carried out on nine healthy female subjects without any history of stone formation and aged 26–35 years. Each juice was tested in a 5 d study. During the study, the subjects received a standardized diet. Fluid intake of 2·75 litres was composed of 2·25 litres neutral mineral water, 0·4 litre coffee and 0·1 litre milk. On the fourth and fifth day 0·5 litre mineral water was partly substituted by 0·5 or 1·0 litre juice under investigation respectively. The influence on urinary variables was evaluated in 24 h urine samples. In addition, the BONN risk index of CaOx, relative supersaturation (RS)CaOx crystallization was determined. Due to an increased pH value and an increased citric acid excretion after consumption of each juice, the RSCaOx decreased statistically significantly (P<0·05) for grapefruit juice, but not significantly for orange and apple juice. The BONN risk index yielded a distinct decrease in the crystallization risk. We showed that both grapefruit juice and apple juice reduce the risk of CaOx stone formation at a magnitude comparable with the effects obtained from orange juice.

It is well known from behavioural experiments that children with specific language impairment (SLI) have difficulties discriminating consonant–vowel (CV) syllables such as /ba/, /da/, and /ga/. Mismatch negativity (MMN) is an auditory event-related potential component that represents the outcome of an automatic comparison process. It could, therefore, be a promising tool for assessing central auditory processing deficits for speech and non-speech stimuli in children with SLI. MMN is typically evoked by occasionally occurring ‘deviant’ stimuli in a sequence of identical ‘standard’ sounds. In this study MMN was elicited using simple tone stimuli, which differed in frequency (1000 versus 1200Hz) and duration (175 versus 100ms) and to digitized CV syllables which differed in place of articulation (/ba/, /da/, and /ga/) in children with expressive and receptive SLI and healthy control children (n=21 in each group, 46 males and 17 females; age range 5 to 10 years). Mean MMN amplitudes between groups were compared. Additionally, the behavioural discrimination performance was assessed. Children with SLI had attenuated MMN amplitudes to speech stimuli, but there was no significant difference between the two diagnostic subgroups. MMN to tone stimuli did not differ between the groups. Children with SLI made more errors in the discrimination task, but discrimination scores did not correlate with MMN amplitudes. The present data suggest that children with SLI show a specific deficit in automatic discrimination of CV syllables differing in place of articulation, whereas the processing of simple tone differences seems to be unimpaired.