RESUMEN
OBJECTIVE: To analyze the correlation between standardized language assessment batteries of toddlers and developmental language delays. METHODS: A total of 319 children with suspected language developmental delays were enrolled in this study retrospectively. They underwent the Receptive and Expressive Vocabulary Test (REVT) for vocabulary development assessment and at least one of two language assessment batteries: The Sequenced Language Scale for Infants (SELSI) or the Preschool Receptive-Expressive Language Scale (PRES) for language development assessment. The correlation of the results for receptive and expressive language between the scales were analyzed. RESULTS: The participants were divided into two groups: SELSI and REVT (n=45) and PRES and REVT (n=273). When the children's results were classified into groups (average, mild delay, and delay), receptive and expressive scores were significantly correlated with each other in both SELSI-REVT and PRES-REVT groups. In addition, the correlation of mean developmental age between tests are analyzed. In the SELSI-REVT group, there was weak correlation of mean developmental age between tests for receptive and expressive language. In the PRES-REVT group, there was a strong positive correlation of mean developmental age for receptive and expressive language in children aged >36 months. Attention deficits during the test was found to be the statistically significant factor affecting the differences between the tests. The odds ratios for receptive and expressive language were 2.60 (95% confidence interval,1.15-5.84) and 1.94 (95% confidence interval, 1.15-3.27), respectively. CONCLUSION: This study examined the correlations and influencing factors between language development evaluation tools for toddlers. An integrated interpretation of comprehensive language and vocabulary evaluation tools may be possible in children older than 3 years of language developmental age.
RESUMEN
The rheological properties of polycarbonate/acrylonitrile-butadiene-styrene (PC/ABS) blends with various blend ratios are investigated at different temperatures to determine the shear dependent chain motions in a heterogeneous blend system. At low frequency levels under 0.1 rad/s, the viscosity of the material with a blend ratio of 3:7 (PC:ABS) is higher than that of pure ABS polymer. As the temperature increases, the viscosities of ABS-rich blends increase rather than decrease, whereas PC-rich blends exhibit decrease in viscosity. Results from the time sweep measurements indicate that ordered structures of PC and the formation and breakdown of internal network structures of ABS polymer occur simultaneously in the blend systems. Newly designed sequence test results show that the internal structures formed between PC and ABS polymers are dominant at low shear conditions for the blend ratio of 3:7 and effects of structural change and the presence of polybutadiene (PBD) become dominant at high shear conditions for pure ABS. The results of yield stress and relaxation time for PC/ABS blends support this phenomenon. The specimen with a blend ratio of 3:7 exhibited the highest value of yield stress at high temperature among others, which implies that the internal structure become stronger at higher temperature. The heterogeneity of ABS-rich blends increases whereas that of PC-rich blends decreases as temperature increases.
RESUMEN
In this study, the effects of etching time and temperature on the adhesion of plated layers of acrylonitrile butadiene styrene (ABS) were investigated. The ABS surface micropores, which act as anchors to improve the adhesion of the plated layer, increased in numbers as the etching temperature increased. Adhesion was maximum at the etching time of 9 min at etching temperatures of 60 and 70 °C. For the etching times of 12 and 15 min, micropores on the ABS surface were incompletely filled during electroplating because the pores were both deep and narrow. The adhesion strength was decreased by these unfilled micropores, which further reduced the anchor effect. The ratio of the increased surface area ratio of the ABS to that of the plated surface was maximized at 9 min etching time, at which point the plating adhesion was also maximized.