06/02309 Effect of changes in the level of light harvesting complexes of Rhodobacter sphaeroides on the photo heterotrophic production of hydrogen: Kim, E.-J. et al. International Journal of Hydrogen Energy, 2006, 31, (4), 531–538.
- Book ID
- 104280006
- Publisher
- Elsevier Science
- Year
- 2006
- Weight
- 354 KB
- Volume
- 47
- Category
- Article
- ISSN
- 0140-6701
No coin nor oath required. For personal study only.
✦ Synopsis
granular coconut and palm kernel shells as substitutes for conventional coarse aggregate in gradation of 0%, 25%, 50%, 75% and 100%. Two mix ratios (1:1:2 and 1:2:4) were used. A total of 320 cubes of size 100 × 100 x 100 mm were cast, tested and their physical and mechanical properties determined. The results of the tests showed that the compressive strength of the concrete decreased as the percentage of the shells increased in the two mix ratios. However, concrete obtained from coconut shells exhibited a higher compressive strength than palm kernel shell concrete in the two mix proportions. The results also indicated cost reduction of 30% and 42% for concrete produced from coconut shells and palm kernel shells, respectively. Considering the strength/economy ratio, it was concluded that coconut shells were more suitable than palm kernel shells when used as substitute for conventional aggregates in concrete production.
06/02304 Biochemistry of hydrogen metabolism in
Chlamydomonas reinhardtii wild type and a Rubisco-less mutant White, A. L. and Melis, A. International Journal o/" Itydrogen Energy, 2006, 31, (4), 455-464. Sulfate nutrient-deprivation in Chlamydomonas rei~zhardtii brings about prompt degradation of Rubisco and a concomitant substantial accumulation of starch. These changes precede hydrogen (H2) photoevolution by the cells. The cause-and-effect relationship between Rubisco loss, starch accumulation and subsequent H;-photoevolution in C. reinhardtii, and the role of illumination for these changes to occur, was investigated in this work. A Rubisco-less and acetaterequiring mutant of C. reinhardtii (CC2653) was employed as a tool in this investigation and compared to the wild type (WT) in terms of protein and starch metabolic flux and H2-evolution upon sulfur deprivation. Results showed a prompt Rubisco degradation and concomitant 10-fold starch accumulation in the WT in the light, which was completed within 48 h of S-deprivation. This was followed by a regulated starch degradation and concomitant H,-photoevolution, which lasted for up to 120 h in S-deprivation. This massive flux of primary metabolites (protein and starch) did not occur in the dark in the WT, suggesting a strictly light-dependent and integrated process in metabolite rearrangement and H2-photoevolution in C. reinhardtii. The Rubisco-tess CC2653 mutant failed to accumulate starch upon Sdeprivation in the light or dark and also failed to evolve H2 gas. These results suggested a temporal cause-and-effect relationship between the light-dependent catabolism of Rubisco and starch accumulation, and the subsequent ability of the cell to perform a light-dependent starch degradation and H2-photoevolution. The regulated starch breakdown in the light apparently provides the endogenous substrate that supports H2-evolution, both by feeding electrons into the plastoquinone pool in chloroplasts, and indirectly by sustaining mitochondrial respiration for the maintenance of anaerobiosis in the cell.