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We undertook a comparative study of magnetic resonance imaging (MRI) vertebral morphometry of thoracic vertebrae of girls with adolescent idiopathic thoracic scoliosis (AIS) and age and gender-matched normal subjects, in order to investigate abnormal differential growth of the anterior and posterior elements of the thoracic vertebrae in patients with scoliosis. Previous studies have suggested that disproportionate growth of the anterior and posterior columns may contribute to the development of AIS. Whole spine MRI was undertaken on 83 girls with AIS between the age of 12 and 14 years, and Cobb’s angles of between 20° and 90°, and 22 age-matched controls. Multiple measurements of each thoracic vertebra were obtained from the best sagittal and axial MRI cuts. Compared with the controls, the scoliotic spines had longer vertebral bodies between T1 and T12 in the anterior column and shorter pedicles with a larger interpedicular distance in the posterior column. The differential growth between the anterior and the posterior elements of each thoracic vertebra in the patients with AIS was significantly different from that in the controls (p < 0.01). There was also a significant positive correlation between the scoliosis severity score and the ratio of differential growth between the anterior and posterior columns for each thoracic vertebra (p < 0.01). Compared with age-matched controls, the longitudinal growth of the vertebral bodies in patients with AIS is disproportionate and faster and mainly occurs by endochondral ossification. In contrast, the circumferential growth by membranous ossification is slower in both the vertebral bodies and pedicles.

Length modulation of cardiac muscle is manifested in the Frank–Starling relation of the heart. Recently, it has been shown that length-dependent changes in SH reactivity of cardiac troponin C (cTnC) occurred in association with cross-bridge attachment and Ca2+. However, the presence of two SH groups (Cys-35 and Cys-84) in the regulatory region of cTnC complicates efforts to detect conformational changes. In this study skinned porcine cardiac fibers were reacted with 7-diethylamino-3-[4′maleimidylphenyl]-4-methylcoumarin (CPM). Alkaline urea gel electrophoresis, along with protein elution, was used to isolate filament bound cTnC. Analysis of fluorescence measurement showed that there is a Ca2+-increased fluorescence for CPM-labeled cTnC in long fibers (sarcomere length = 2.2 ∼ 2.5 μm) but not in short fibers (sarcomere length = 1.6 ∼ 1.8 μm). In addition, the labeled cTnC was measured for the fluorescence decrease over time by adding a non-fluorescence energy acceptor, 4-dimethylaminophenylazophenyl-4′maleimide (DABMI), in the presence and absence of Ca2+. Fluorescence quenching by DABMI is not affected by Ca2+in long fibers but it is significantly increased in short fibers. However, the fibers maintained in the relaxed state with 5 mM MgATP and 1 mM Vanadate showed no length effect on the CPM-labeled cTnC in terms of the Ca2+-mediated changes in fluorescence spectrum and in fluorescence quenching by DABMI. All together, our results suggest that the relative reactivities of Cys-35 and Cys-84 vary with sarcomere length.

The nonstructural protein 3 (NS3) of hepatitis C virus (HCV) possesses protease, nucleoside triphosphatase, and helicase activities. Although the enzymatic activities have been extensively studied, the ATP- and RNA-binding domains of the NS3 helicase are not well-characterized. In this study, NS3 proteins with point mutations in the conserved helicase motifs were expressed in Escherichia coli, purified, and analyzed for their effects on ATP binding, RNA binding, ATP hydrolysis, and RNA unwinding. UV cross-linking experiments indicate that the lysine residue in the AX(4)GKS motif is directly involved in ATP binding, whereas the NS3(GR1490DT) mutant in which the arginine-rich motif (1486-QRRGRTGR-1493) was changed to QRRDTTGR bound ATP as well as the wild type. The binding activity of HCV NS3 helicase to the viral RNA was drastically reduced with the mutation at Arg1488 (R1488A) and was also affected by the K1236E substitution in the AX(4)GKS motif and the R1490A and GR1490DT mutations in the arginine-rich motif. Previously, Arg1490 was suggested, based on the crystal structure of an NS3-deoxyuridine octamer complex, to directly interact with the gamma-phosphate group of ATP. Nevertheless, our functional analysis demonstrated the critical roles of Arg1490 in binding to the viral RNA, ATP hydrolysis, and RNA unwinding, but not in ATP binding.

Because cell growth and differentiation are regulated by complex interactions among different signaling pathways, a growth defect affects subsequent differentiation. We report on a growth-defective mutant of Arabidopsis, called eld1 (elongation defective 1). Cell elongation was impaired in every organ examined. Later characteristics of the eld1 phenotype include defective vascular tissue differentiation, the inability to grow in soil, ectopic deposition of suberin around twisted vascular bundles, the de-etiolation phenotype, and continuation of shoot development and flowering in the dark. The dwarf phenotype of eld1 could not be rescued by treatment with exogenous growth regulators. Because defective cell elongation is the earliest and most universal feature detected in eld1 mutants, control of or activity in cell elongation may be the primary function of the ELD1 gene. The impaired cell growth results in pleiotropic effects on cell proliferation and differentiation, and the retardation in hypocotyl elongation enables growth and development in darkness.

A complete theoretical treatment for the determination of thermal diffusivity of superlattices by the “mirage” technique has been performed. An effective “medium approximation” model of the thermal conductivity and thermal diffusivity of both sublayers is presented, which is different from the simple models with the thermal diffusivity or thermal conductivity in series or parallel. The numerical calculation of the transverse component of the probe beam deflection in the “mirage” effect shows that the results obtained from the complete thermal-wave theory and the “medium approximation” model, for the optically and thermally thick superlattices, are in good agreement with each other. However, the further study on the thermally thin superlattices shows that either the series or the parallel model of the thermal conductivity should be chosen according to whether the thermal impedance of the superlattice is larger or less than that of substrate, respectively.

From 1987 to 1990, 45 children with cerebral palsy underwent percutaneous elongation of the Achilles tendon (71 ankles); the mean age was 5.7 years. Most suffered from spastic diplegia or hemiplegia. A three-step cut technique was used, the limb immobilised in a long leg fibreglass cast and immediate weightbearing allowed. Follow up was from 2 to 5 years. Satisfactory results were obtained with significant improvement in walking in 89%.

The sonographic appearance of the sternocleidomastoid muscles of 36 children with congenital muscular torticollis was studied. Sternocleidomastoid tumour was detected in all of them and the images were more complex than described in the literature. A patchy echotexture was as frequent as a homogeneous echo-texture, and was more common in the younger child. The echogenicity of the mass could be hyperechoic, isoechoic or hypoechoic relative to normal muscle. A hypoechoic rim surrounding the mass was frequently present. Change of the proportion of the mass relative to the entire musclemass complex in different ages matching clinical observations was also noted. These sonographic findings would be important in establishing a sonographic diagnosis. The higher sensitivity of ultrasound in detection of sternocleidomastoid tumour over clinical methods, and the importance of the sonographic findings in the management of congenital muscular torticollis were also discussed.

Abstract Objective To determine the relation of puberty, physical activity, physical fitness, and calcium intake with bone mineral content (BMC) of the distal radius, and on bone mineral density (BMD) of the L2 to L4 vertebrae in a group of healthy Chinese adolescents. Design Cross sectional survey. Subjects A group of 179 healthy Chinese adolescents (92 boys and 87 girls) aged 12 to 13 years enrolled in the first year of the Tii Junior High School in Shatin, Hong Kong. Ninety four of the pupils enrolled were in the physical education major class (PE), and the other 85 were in the art major class (ARTS). Main outcome measures Correlation of BMC of the distal radius and BMD of the L2 to L4 vertebrae with level of physical activity, physical fitness (isometric and isokinetic), muscle strength of the upper and lower limb, and calcium intake. Results BMC of the distal radius and BMD of the L2 to L4 vertebrae were significantly positively correlated. Univariate and regression analysis showed that age, pubertal staging, physical fitness, and muscle strength were significantly associated with bone mass in a positive way. Calcium intake and type of sport practised did not exert a significant influence on BMC of the distal radius and BMD of the L2 to L4 vertebrae in boys. The results for the BMD of the L2 to L4 vertebrae were similar in girls and boys; however, in girls, the BMC of the distal radius had a negative correlation with calcium intake. Physical fitness was a significant positive predictor of BMD of the L2 to L4 vertebrae. Conclusions Among Chinese adolescents bone mass was positively influenced by certain measures of physical fitness as well as by age, weight, and pubertal stage.

An improved photoelastic modulator (PEM) employing two piezoelectric transducers and incorporating a new ir zinc selenide (ZnSe) optical element is described. The 0.64-cm thick PEM is capable of obtaining quarter-wave retardation from 0.55 μm to 13.0 μm. Previously no single, high quality, low static strain PEM element existed for this wavelength range. We have also constructed other PEM’s using optical elements composed of fused quartz, calcium fluoride, and KRS-5. The important optical and mechanical properties are measured and compared.

In circular dichroism (CD) measurement using conventional modulation-spectroscopy techniques, spurious signals arise when birefringence and polarization sensitivity are simultaneously present along the optical path. We show that when such spurious signals originate in components subsequent to the sample, they can be removed by a second modulator placed immediately after the sample. This second modulator, which must have a different frequency from the first and must be adjusted to a specific retardation level, scrambles the polarization of the light so that the time average of the signal is zero. The true CD signal of the sample, on the other hand, is unaffected. An experimental demonstration of this result is presented. Spurious signals due to imperfections in components before the sample or in the sample itself cannot be nulled in the same manner.

Pressure therapy is a well-recognized form of treatment for postburn hypertrophic scar, but monitoring scar maturation has always been a problem in clinical management. By measuring the extensibility of scar tissue during pressure therapy, monitoring of scar maturation was attempted. Altogether 250 measurements were made on 12 patients, with an average follow up of 13.5 months. The results were analyzed mathematically, and the usefulness of this method is discussed.

Displaced fractures of the forearm in children are often treated conservatively, but there is a relatively high incidence of redisplacement, malunion and consequent limitation of function. We have performed percutaneous Kirschner (K) wire fixation in 72 such children under the age of 14 years, of which 57 were reviewed for our study. Both the radius and ulna were fractured in 45 (79%), the radius only in eight and the ulna only in four. The mean initial angulation was 19° in the lateral plane and 9° in the anteroposterior plane for the radius and 15° and 9°, respectively, for the ulna. In 42 patients (74%) we performed closed reduction. In the remaining 15 (26%) closed reduction failed and an open reduction, through a minimal approach, was required before K wiring.At a mean follow-up of 20 months all patients had good functional results with an excellent range of movement. Only five had angulation of from 10° to 15° and none had nonunion, premature epiphyseal closure or deep infection. Percutaneous intramedullary K wiring for forearm diaphyseal fracture is a convenient, effective and safe operation, with minimal complications.

The method of the eigenfunction expansion, also known as the expansion in normal modes, is employed to study numerically the axisymmetric excitation of the thermoelastic waves in plates by a pulsed laser. This method gives a systematic treatment and allows one to investigate not only the quasistatic and dynamic thermoelastic responses of pulsed photothermal deformation on the time scale of 1 µs, but also the thermoelastic generation of longitudinal, transverse, and surface acoustic waves in thick materials, as well as the excitations of the Rayleigh–Lamb wave modes in thin plates. The formalism is particularly suitable for waveform analyses of the excitations of transient Lamb waves in thin plates because one needs only to calculate the contributions of several lower eigenmodes. The numerical technique provides a quantitative tool for the experimental determination of material properties, especially the mechanical and elastic properties of free-standing films and thicker sheet materials by thermoelastic detection.