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Height Change (height + change)
Selected AbstractsA Randomized School-Based Jumping Intervention Confers Site and Maturity-Specific Benefits on Bone Structural Properties in Girls: A Hip Structural Analysis Study,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 3 2002M. A. Petit Abstract We compared 7-month changes in bone structural properties in pre- and early-pubertal girls randomized to exercise intervention (10-minute, 3 times per week, jumping program) or control groups. Girls were classified as prepubertal (PRE; Tanner breast stage 1; n = 43 for intervention [I] and n = 25 for control [C]) or early-pubertal (EARLY; Tanner stages 2 and 3; n = 43 for I and n = 63 for C). Mean ± SD age was 10.0 ± 0.6 and 10.5 ± 0.6 for the PRE and EARLY groups, respectively. Proximal femur scans were analyzed using a hip structural analysis (HSA) program to assess bone mineral density (BMD), subperiosteal width, and cross-sectional area and to estimate cortical thickness, endosteal diameter, and section modulus at the femoral neck (FN), intertrochanter (IT), and femoral shaft (FS) regions. There were no differences between intervention and control groups for baseline height, weight, calcium intake, or physical activity or for change over 7 months (p > 0.05). We used analysis of covariance (ANCOVA) to examine group differences in changes of bone structure, adjusting for baseline weight, height change, Tanner breast stage, and physical activity. There were no differences in change for bone structure in the PRE girls. The more mature girls (EARLY) in the intervention group showed significantly greater gains in FN (+2.6%, p = 0.03) and IT (+1.7%, p = 0.02) BMD. Underpinning these changes were increased bone cross-sectional area and reduced endosteal expansion. Changes in subperiosteal dimensions did not differ. Structural changes improved section modulus (bending strength) at the FN (+4.0%, p = 0.04), but not at the IT region. There were no differences at the primarily cortical FS. These data provide insight into geometric changes that underpin exercise-associated gain in bone strength in early-pubertal girls. [source] Atomic Force Microscopy Characterization and Interpretation of Thin-Film Poly(butylene adipate) Spherulites with Ring BandsMACROMOLECULAR RAPID COMMUNICATIONS, Issue 15 2008Andreas Frömsdorf Abstract Atomic force microscopy characterization has been conducted to reveal the morphological difference between single-ring bands in poly(butylene adipate) (PBA). Furthermore, morphological features of the ring-less Maltese-cross spherulites are compared to the ring-band spherulites. Periodic changes in height seem to be common for either the ring-band or ring-less (Maltese-cross) crystal domains; however, the steepness in height change is greater for the ring-band crystal, while height change in the ring-less crystal exhibits a terrace-like layer pattern. In the ring-band crystal region, the lamellar stalks, which taper off to pointed needle-like stalks, monotonously protrude out of the layers of softer materials, with no signs of twisting, bending, or turning. In contrast, all lamellae in the ring-less (Maltese-cross) crystal region are uniform platelets arranged like flower petals in a layered pattern. [source] Catch-up Growth or Regression to the Mean?AMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 4 2005Recovery from Stunting Revisited An important question for policy is the extent to which catch-up growth can ease the impact of early stunting. Martorell et al. (1992) showed that stunted Guatemalan infants remain stunted into adulthood, whereas Adair (1999) found appreciable catch-up growth in Filipino children from 2,12 years. Both groups defined catch-up as an inverse correlation between early height and subsequent growth, but Martorell based the correlation on height, whereas Adair used height z scores. The statistical phenomenon of regression to the mean is much like catch-up growth, an inverse correlation between initial height and later height gain. The objective of this study was to reexamine the relationship between stunting and later catch-up growth in the context of regression to the mean. The design was a theoretical analysis showing that catch-up growth is more evident based on height z scores than on height, validated using data on 495 stunted South African children seen at 2 and 5 years of age. The correlation between height at 2 and height change from 2 to 5 was small based on height (,0.11) but large and highly significant based on height z score (,0.58), providing strong evidence of catch-up growth. We argue that catch-up growth should be estimated using height z score not height and that catch-up is present only when the change in z score exceeds that predicted by regression to the mean. This leads to a compact definition of catch-up growth: if z1 and z2 are the initial and final (mean) height z scores, and r is the correlation between them, then catch-up growth for groups or individuals is given by (z2 , rz1). Am. J. Hum. Biol. 17:412,417, 2005. © 2005 Wiley-Liss, Inc. [source] Gingival and dentofacial changes in adolescents and adults 2 to 10 years after orthodontic treatmentJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 9 2008Georges-André Theytaz Abstract Background: Information about long-term changes of the shape of the gingival margin is missing. Aim: To monitor 8 year changes of the gingival contour occurring in adolescents and adults and relate these changes to dentofacial growth. Subjects and method: Forty adolescents (mean age 16.3), and 14 adults (mean age 29.7) were included in the study with photographs, radiographs and casts taken 2 and 10 years after orthodontic treatment. The gingival contour of upper central incisors and the midline passing through the contact surface of both teeth were traced digitally using calibrated photographs. Changes were measured on seven standardized lines of the gingival contour. Lower facial height changes and tooth eruption were measured using lateral cephalograms. Results: Adolescents and adults showed a central mean apical displacement of the gingival margin of 0.51 mm (SD 0.4 mm) and 0.13 mm (SD 0.17 mm), respectively. This displacement decreased by moving away from the centre. The gingival displacement was associated to the individual's lower facial height augmentation, r=0.63 (p<0.001). Conclusions: Apical displacement of the gingival contour of the upper central incisors takes place during adolescence following a semi-lunar shape. Growth explains parts of these changes. [source] | ||||||||||