Polyunsaturated fatty acids (PUFAs) have been reported to have an anabolic effect on bone in vivo, but comparative studies to identify inhibitors of osteoclast formation amongst ω3- and ω6-PUFAs are still lacking. Here we assessed the effects of the ω3-PUFAs, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) and the ω6-PUFAs, arachidonic acid (AA) and γ-linolenic acid (GLA) on a RAW264.7 osteoclast differentiation model. The effects of PUFAs on RANKL-induced osteoclast formation were evaluated by counting tartrate resistant acid phosphatase (TRAP)-positive multinucleated cells. PUFAs significantly inhibited RANKL-induced osteoclast formation in a dose-dependent manner with AA- and DHA-mediated inhibition being the strongest. Furthermore, RANKL-induced mRNA- and protein expression of the key osteoclastogenic genes cathepsin K and TRAP were inhibited by AA and more potently by DHA. Owing to the attenuated osteoclastogenesis by DHA and AA, actin ring formation and bone resorptive activity of these cells as evaluated on bone-mimetic plates were severely compromised. Hence, of the tested PUFAs, AA and DHA were found to be the most effective in inhibiting RANKL-induced osteoclast formation with the latter providing the strongest inhibitory effects. Collectively, the data indicates that these PUFAs may play an important role in regulating bone diseases characterized by excessive osteoclast activity.

Two black aqueous tea extracts of Camellia sinensis, (selenium-rich black tea (Se-BTE) and regular black tea (R-BTE)) were assessed for their total phenolic content (TPC) and antioxidant properties. Aqueous tea extracts were prepared using different extraction temperature and time. TPC was measured using the Folin-Ciocalteu method, while antioxidant activity was measured by ferric-reducing antioxidant power (FRAP) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) assays. The R-BTE showed significantly higher TPC (P < 0.05) and antioxidant activity (P < 0.05) than the Se-BTE, which may be due to these being different cultivars, or differences in growing conditions. Our findings demonstrate that both extraction temperature and time are important determinants of extracted TPC and antioxidant activities of these teas. In addition and in contrary to our expectations, the high level of organic selenium in black tea did not enhance the antioxidant activity when compared with black tea containing very low level of organic selenium. Other elements and minerals may contribute to the high antioxidant activity detected in the regular black tea.

Audiovisual recordings of lectures are available to many students in all disciplines. The use of lecture recordings has been studied extensively, but it is still not clear how, or how much, they are actually used. Previous analysis of their use has been based on either survey data or computer logs of access. In the latter case, measurements of actual use have usually been based on counts of the number of times recordings have been accessed. This does not distinguish those that happen accidentally (‘hits’), from those that might permit learning (‘views’). This distinction is essential to the meaningful analysis of the log of the actual use of recorded lectures. Using the access logs of undergraduate science students, we show that the distribution of the durations of the access of recordings of scheduled lectures has two distinct components. The most rapid of these is complete within three minutes and we infer that it reflects the behaviour of students searching among recordings. This inference is based on a comparison of these distributions with those of (i) recordings made automatically during a non-teaching period and (ii) individual users. This is also consistent with the pattern of usage by students searching for a specific recording.