Low back pain in adolescents is perceived to be uncommon in the clinic setting. However, previous studies have suggested that it may be an important and increasing problem in this age-group. The aim of this study was to determine the prevalence and important symptom characteristics of low back pain such as duration, periodicity, intensity, disability and health seeking behaviour at young ages. A population-based cross-sectional study was conducted including 1446 children aged 11-14 years in the North-West of England. A self-complete questionnaire was used to assess low back pain prevalence, symptom characteristics, associated disability and health seeking behaviour. An additional self-complete questionnaire amongst parents sought to validate pain reporting. The 1-month period prevalence of low back pain was 24%. It was higher in girls than boys (29 vs. 19%; 2=14.7, P<0.001) and increased with age in both sexes (P<0.001). Of those reporting low back pain, 94% experienced some disability, with the most common reports being of difficulty carrying school bags. Despite this high rate of disability, few sought medical attention. Adolescent low back pain is common although medical attention is rarely sought. Such symptoms in childhood, particularly as they are so common, may have important consequences for chronic low back pain in adulthood.

Responsiveness varied according to which method was used in its calculation. The responsiveness of the SF-36 questionnaire shows that it can be a useful adjunct in the assessment of patients with low back pain when combined with disease-specific questionnaires.

Xerogels and porous materials for specific applications such as catalyst supports, CO2 capture, pollutant adsorption, and selective membrane design require fine control of pore structure, which in turn requires improved understanding of the chemistry and physics of growth, aggregation, and gelation processes governing nanostructure formation in these materials. We used time-resolved dynamic light scattering to study the formation of resorcinol-formaldehyde gels through a sol-gel process in the presence of Group I metal carbonates. We showed that an underlying nanoscale phase transition (independent of carbonate concentration or metal type) controls the size of primary clusters during the preaggregation phase; while the amount of carbonate determines the number concentration of clusters and, hence, the size to which clusters grow before filling space to form the gel. This novel physical insight, based on a close relationship between cluster size at the onset of gelation and average pore size in the final xerogel results in a well-defined master curve, directly linking final gel properties to process conditions, facilitating the rational design of porous gels with properties specifically tuned for particular applications. Interestingly, although results for lithium, sodium, and potassium carbonate fall on the same master curve, cesium carbonate gels have significantly larger average pore size and cluster size at gelation, providing an extended range of tunable pore size for further adsorption applications.

A deeper understanding of the chemistry and physics of growth, aggregation, and gelation processes involved in the formation of xerogels is key to providing greater control of the porous characteristics of such materials, increasing the range of applications for which they may be utilized. Time-resolved dynamic light scattering has been used to study the formation of resorcinol-formaldehyde gels in the presence of combinations of Group I (Na and Cs) and Group II (Ca and Ba) metal carbonates. It was found that the combined catalyst composition, including species and times of addition, is crucial in determining the end properties of the xerogels via its effect on growth of clusters involved in formation of the gel network. Combination materials have textural characteristics within the full gamut offered by each catalyst alone; however, in addition, combination materials that retain the small pores associated with sodium carbonate catalyzed xerogels exhibit a narrowing of the pore size distribution, providing an increased pore volume within an application-specific range of pore sizes. We also show evidence of pore size tunability while maintaining ionic strength, which significantly increases the potential of such systems for biological applications.

The present study has shown that the shuttle walking test is a reliable and responsive test within a group of patients with low back pain, with or without sciatica. It is simple to administer and provides a quick method of measuring one aspect of a patient's physical function.