Transcrystalline morphology of nylon 6 on the surface of aramid fibers

In this paper, the isothermal crystallization of nylon 6 in the presence of Kevlar 129 fiber was investigated by polarized optical microscopy (POM). The formation of a transcrystalline domain was found to be mainly controlled by crystallization conditions, such as the temperature of the isothermal crystallization, residual time at melting temperature and the cooling rate of the melt. The nucleation rate of nylon 6 on the fibers was mainly affected by the crystallization temperature. The interfacial transcrystallinity of nylon 6 occurred on the surface of Kevlar 129 fiber in the temperature range 130–190 °C. The reason for the formation of interfacial transcrystalline morphology is discussed from the molecular level, based on the understanding of the packing mode of nylon 6 chains around fibers and the interaction between matrix and fibers. It was found that the lattice matching and hydrogen‐bonding between nylon 6 and poly(p‐phenylene terephthalamide) (PPTA) crystals play an important role in the epitaxial crystallization. Copyright © 2004 Society of Chemical Industry     

Prion protein immunohistochemical staining in the brains of monkeys with transmissible spongiform encephalopathy

BACKGROUND: Spirituality is receiving greater attention in the medical literature, especially in the family practice journals. A widely applicable instrument to assess spirituality has been lacking, however, and this has hampered research on the relationship between spirituality and health in the clinical setting. METHODS: A new instrument, called the Spiritual Involvement and Beliefs Scale, was designed to be widely applicable across religious traditions, to assess actions as well as beliefs to address key components not assessed in other available measures, and to be easily administered and scored. The instrument is a questionnaire containing 26 items in a modified Likert-type format. Following careful pretesting, the instrument was administered to 50 family practice patients and 33 family practice educators. The validity and reliability of the instrument were then evaluated. RESULTS: By several measures, instrument reliability and validity are very good, with high internal consistency (Cronbach's alpha = .92); strong test-retest reliability (r = .92); a clear four-factor structure; and a high correlation (r = .80) with another established measure of spirituality, the Spiritual Well-Being Scale. CONCLUSIONS: The Spiritual Involvement and Beliefs Scale (SIBS) appears to have good reliability and validity. Compared with other instruments that assess spirituality, the SIBS has several theoretical advantages, including broader scope, use of terms that avoid cultural-religious bias, and assessment of both beliefs and actions. More testing is underway to further assess its usefulness.     

Bone alkaline phosphatase and collagen markers as early predictors of height velocity response to growth-promoting treatments in short normal children

OBJECTIVE: A number of long-term research studies are in progress to evaluate the effects of treatment with GH on growth and final height in children with short stature but no demonstrable abnormality of GH secretion. Such treatment is invasive, expensive and carries some risk to the child. An early indication of growth response would allow restriction of treatment to those children most likely to benefit, but anthropometric measurements are relatively subjective, insensitive and imprecise. The aim of this study was to evaluate bone alkaline phosphatase, procollagen Type I C-terminal propeptide, procollagen Type III N-terminal propeptide and the cross-linked carboxy-terminal telopeptide of Type I collagen as early biochemical predictors of height velocity response to growth-promoting treatments in short normal children. DESIGN: A prospective intervention study, partially placebo controlled on a double blind basis. PATIENTS: Fifty healthy children with familial short stature or constitutional delay in growth and puberty (8 girls, 42 boys, ages 5.5-16.5 years and all either prepubertal (45) or in very early puberty (5 boys) at the start of treatment) were treated with placebo (6), GH alone (32), GH plus oxandrolone (8) or GH plus testosterone (4). MEASUREMENTS: Bone alkaline phosphatase and the collagen markers were measured at the start of treatment and 3 months later. Height velocity was calculated at the start of treatment and again after one year. RESULTS: Pre-treatment biochemical marker concentrations did not predict height velocity response after one year. Increments in all markers after 3 months were significantly correlated with height velocity increments after one year of treatment, the highest correlations being observed for bone alkaline phosphatase (r = 0.67, P < 0.0001) and procollagen Type III N-terminal propeptide (r = 0.57, P < 0.0001). Highly significant correlations (P < 0.0001) were also observed between bone alkaline phosphatase and procollagen Type I C-terminal propeptide (r = 0.55) and between procollagen Type III N-terminal propeptide and the cross-linked carboxy-terminal telopeptide of Type I collagen (r = 0.62). Multiple linear regression with stepwise selection of variables identified bone alkaline phosphatase and procollagen Type III N-terminal propeptide as the only two independent variables that contributed significantly to the prediction of height velocity response after one year (analysis of variance, P < 0.0001). Together they predicted 59% of the variability in height velocity response after a year. CONCLUSIONS: The best early predictors of height velocity response were bone alkaline phosphatase (a protein found in hypertrophic chondrocytes in the epiphyseal growth plate, in calcifying matrix vesicles and in mature osteoblasts) and procollagen Type III N-terminal propeptide, a marker of interstitial fibril biosynthesis in soft tissues. Using these markers, GH treatment could be targeted to those children most likely to benefit in the medium term.