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“Study Design. This study is a repeated measures design to measure the lumbar spine response to typical school backpack
loads in healthy children. Screening Library The lumbar spine in this setting was measured for the first time by an upright magnetic resonance imaging (MRI) scanner.
Objective. The purpose of this study is to measure the lumbar spine response to typical school backpack loads in healthy children. We hypothesize that backpack loads significantly increase disc compression and lumbar curvature.
Summary of Background Data. Children commonly carry school backpacks of 10% to 22% bodyweight. Despite growing concern among parents about safety, there are no imaging studies which describe the effect of backpack loads on the spine in children.
Methods. Three boys and 5 girls, age 11 +/- 2 years (mean +/- SD) underwent T2 weighted sagittal and coronal MRI scans of the lumbar spine while standing. Scans were repeated with 4, 8, and 12 kg backpack loads, which represented approximately 10%, 20%, and 30% body weight for our sample. Main outcome measures were disc compression, defined as post-minus preloading disc height, and lumbar asymmetry, defined as the coronal Cobb angle between the superior endplates of S1 and L1.
Results. Increasing backpack loads significantly compressed lumbar disc heights measured ML323 in vivo in the midline
sagittal plane ( P < 0.05, repeated-measures analysis of variance [ANOVA]). Lumbar asymmetry was: 2.23 degrees +/- 1.07 degrees standing, 5.46 degrees +/- 2.50 degrees with 4 kg, 9.18 degrees +/- 2.25 degrees with 8 kg, and 5.68 degrees +/- 1.76 degrees with 12 kg ( mean +/- SE). Backpack loads significantly increased lumbar asymmetry ( Selleck VX-680 P < 0.03, one-way ANOVA). Four of the 8 subjects had Cobb angles greater than 10 during 8-kg backpack loads. Using a visual-analogue scale to rate their pain (0-no pain, 10-worst pain imaginable), subjects reported significant increases in back pain associated with backpack loads of 4, 8, and 12 kg ( P < 0.001, 1-way ANOVA).
Conclusion.
Backpack loads are responsible for a significant amount of back pain in children, which in part, may be due to changes in lumbar disc height or curvature. This is the first upright MRI study to document reduced disc height and greater lumbar asymmetry for common backpack loads in children.”
“An in depth study is performed on the origin of and influences on the formation of tetrahydrofuran (THF) during the first stage of the terephthalic acid (TPA) based synthesis of poly(butylene terephthalate) (PBT). Although many improvements on the synthesis process of PBT have been reported in literature to suppress this undesired side reaction, only few studies reported on the actual mechanism of the THF formation, which is not completely understood. Low molecular weight compounds have been used to model the side reactions occurring during the polymerization reaction.