The wear, wear debris and functional biological activity of non-crosslinked and moderately crosslinked ultrahigh molecular weight polyethylene (UHMWPE) acetabular cups have been com pared when articulating against smooth and intentionally scratched femoral heads. Volumetric wear rates were determined in a hip joint simulator and the debris was isolated from the lubricant and characterized by the percentage number and volumetric concentration as a function of particle size. The volumetric concentration was integrated with the biological activity function determined from in vitro cell culture studies to predict an index of specific biological activity (SBA). The product of specific biological activity and volumetric wear rate was used to determine the index of functional biological activity (FBA). On smooth femoral heads the crosslinked UHMWPE had a 30 per cent lower wear rate, but it had a greater percentage volume of smaller, more biologically active particles, which resulted in a similar index of FBA compared with the non-crosslinked material. On the scratched femoral heads the volumetric wear rate was three times higher for the moderately crosslinked UHMWPE and two times higher for the non-crosslinked UHMWPE compared with the smooth femoral heads. This resulted in a higher wear rate for the moderately crosslinked material on the scratched femoral heads. All the differences in wear rate were statistically significant. There were only small differences in particle volume concentration distributions, and this resulted in similar indices of FBA which were approximately twice the values of those found on the smooth femoral heads. Both materials showed lower wear and FBA than for previously studied aged and oxidized UHMWPE gamma irradiated in air. However, this study did not reveal any advantage in terms of predicted FBA for moderately crosslinked UHMWPE compared with non-crosslinked UHMWPE.

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Wear performance and debris-size distribution of vitamin E (DL-a tocopherol, VE)-added ultrahigh molecular weight polyethylene (UHMWPE) was evaluated using a knee-simulator test. VE was mixed with GUR 1050 UHMWPE powder at 0.3 wt%, and the tibial components of the knee joint were made by direct compression molding. The VE-added UHMWPE showed consistently lower wear volume throughout the test. ß

The first cell cycle of Adiantum spores, which is induced by red light (R), was studied with regard to its temporal dependence on Pfr (the active form of phytochrome) and Ca2 . Responses were quantified with increases of the spore content of DNA, thus limiting the investigation to the reactions taking place before the S phase of the cell cycle (i.e. during GO/G1/S transitions). Spores hydrated for more than 2 days in the standard medium (includes 1 millimolar free Ca2+) showed, after stimulation with a saturating R pulse, an increase of DNA beginning at about 25 hours and saturating at about 55 hours. Reversal by far-red light of the inductive effect of R was used to examine the temporal requirement for Pfr. Spores became dependent on the supply of extemal Ca2+ when incubated in a low Ca medium (32 nanomolar free Ca2+ with 10 millimolar EGTA); this culture condition was used, after observing that the DNA increase occurs similarly if Ca2+ is supplied after the R pulse, to examine the temporal requirement for external Ca2 . It was concluded that the GI phase of the spore is separated into three subphases: (a) the Pfr-dependent period which immediately follows the R pulse and varies among individual spores from a few to about 25 hours, (b) the Ca2+-dependent period (about 10 hours) which occurs immediately before the S phase, and (c) a gap (15-20 hours) between the two periods. In the Ca2+-dependent period, spores require the presence of extracellular Ca2+. This period occurs only during a determined time after the R pulse, and the competence of spores to enter the S phase is lost sharply if external Ca2+ is not available continuously during this period.

In general, cell fate is determined primarily by transcription factors, followed by epigenetic mechanisms fixing the status. While the importance of transcription factors controlling cell fate has been well characterized, epigenetic regulation of cell fate maintenance remains to be elucidated. Here we provide an obvious fate conversion case, in which the inactivation of polycomb-medicated epigenetic regulation results in conversion of T-lineage progenitors to the B-cell fate. In T-cell-specific Ring1A/B-deficient mice, T-cell development was severely blocked at an immature stage. We found that these developmentally arrested T-cell precursors gave rise to functional B cells upon transfer to immunodeficient mice. We further demonstrated that the arrest was almost completely canceled by additional deletion of Pax5. These results indicate that the maintenance of T-cell fate critically requires epigenetic suppression of the B-lineage gene program.

Forest plantations cover approximately 1% of the tropical land mass capable of supporting forest cover, i.e., 25.3 × 106 ha. Deforestation issues and the high potential growth rates of tropical plantations are driving an increase in reforestation activities in the tropics. The underlying principles and objectives of competition control here are similar to those in other areas of the world. Timely early competition control, until the tree crop gains dominance on the site, has proven critical to the success of these efforts because of the rapid and persistent development of weed competition on most tropical sites. Plantation survival has been increased by as much as 90% with early competition control and volume growth by more than 50% at 2 years short of rotation age. Manual weed control methods are used most extensively in the tropics. Cover crops and grazing have been used only to a limited extent. However, as economic development continues in many tropical countries, mechanical methods and herbicides are being used more widely. Herbicide usage is somewhat problematic in these areas owing to the lack of effective regulatory programs, limited herbicide research, few people knowledgeable and trained in herbicide use, and misinformation regarding herbicides.

Futtsu Point is a cuspate foreland separating Tokyo Bay and the Uraga Strait. On March 11, 2011, a tsunami generated by the Great East Japan Earthquake entered Tokyo Bay with approximately 2 m height, and flowed over this sand bar, dispersing the sand and leaving an isolated protruding sand bar. This resulted in the seawall at the foot of the sand bar being exposed to waves, increasing the potential for damage. After the tsunami, this isolated sand bar was significantly deformed, a sand spit was formed by the action of wind waves, and the seawall was refilled with sand. The subsequent shoreline changes of this protruding sand bar were measured, and the three-dimensional beach changes were calculated using the BG model (a three-dimensional model for predicting beach changes based on Bagnold's concept).