The process by which cylindrical rods of soft solid paste extrudate are converted into round pellets on a spheronsier (Marumeriser) plate was studied by interrupting spheronisation tests and measuring the size and shape of the pellets. Batches of 20 identical rods (20 mm long, 3 mm diameter) generated by ram extrusion of 47 wt% microcrystalline cellulose/water paste were spheronised at rotational speeds, , between 1200 rpm and 1800 rpm on a laboratory spheroniser. The time to complete spheronisation was found to scale with  -3.6 , which was close to the  -3 dependency predicted by a simple collision model. Breakage occupied the first 10% of the process duration: rounding off was the rate determining step. The evolution of pellet shape was classified into five stages, the duration of which was found to scale with spheronisation time. Pellet shape, quantified by aspect ratio, circularity, shape and angularity factors presented by Sukumaran and Ashmawy (Géotechnique, 2001, Vol 51, 1-9), showed similar behaviour for all  studied. A phenomenological model is proposed which identifies different routes for small and large rod breakage products.

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SUMMARY. The purpose of the study was to evaluate reliability, validity and sensitivity of the Chinese (simple) SF-36v2 in patients with chronic hepatitis B (CHB). Four hundred and sixty patients were recruited and allocated to CHB (CHB without cirrhosis) (n = 323) and CHB-related cirrhosis (n = 137) groups. Internal consistency reliability was estimated with Cronbach's a-coefficient. Convergent and discriminant validity were assessed by item-scale-component correlation. Factorial validity was explored by principal component factor analysis with varimax rotation. Sensitivity was measured with Cohen's effect size (ES), and independent sample t-test between the CHB and CHBrelated cirrhosis groups and between alanine aminotransferase (ALT) normal and abnormal groups after stratifying illness stages. The results showed that Cronbach's a of the total SF-36v2 was 0.92, with the range from 0.72 to 0.87 in the eight scales and 0.76 to 0.77 in the two summary components. Most of the hypothesized item-scale-component correlations were 0.40 or over, and all of such hypothesized correlations were higher than the alternative ones, indicating satisfactory convergent and discriminant validity. Two and seven factors were extracted after varimax rotation at the scale level and item level. The eligible ES with statistically significant independent sample t-test was found in the physical component summary (PCS) and physical function (PF), role-physical (RP), general health (GH), vitality (VT), social functioning (SF) scales by comparison between CHB and CHB-related cirrhosis groups, and in the PCS and PF, GH, SF scales by comparison between the ALT normal and abnormal groups in the stratification of patients with CHB. In conclusion, the Chinese (simple) SF-36v2 has acceptable reliability, validity and sensitivity in patients with CHB.

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