This is an interpretative article for better understanding of trends in bioethanol, starting from the historical background of the primary energy requirements indicated in the 2nd IPCC Report. Methods for production of bioethanol from biomass are briefly described with emphasis on the advantages of enzymatic decomposition of biomass, especially soft cellulosic biomass. The energy efficiency of bioethanol production from soft biomass is computed using results obtained from a model study in which the ethanol raw material was cut grass from golf courses. The role of mega-cities as producers of bioethanol and related new energy forms are also discussed.
When analyzing something according to a previously confirmed protocol, it is inevitable that the levels of the various operating factors may change either intentionally or accidentally. Some aspects of an analytical method are robust and changing the factors has no significant consequences, while others are sensitive and subtle changes may have a significant influence on the final result. Operators should be aware of which factors are important with respect to the method's robustness. It is time-consuming and inefficient to evaluate the effects of the various factors which may influence analytical results using a one-at-a-time procedure. The process could be improved efficiently, however, by using a class of experimental design called Plackett-Burman design, in which only n measurements are needed to evaluate up to n-1 factors. The results of a fractional factorial design are analyzed graphically and/or statistically to examine the effects of each factor on the analytical response. The results could also be used to quantitatively calculate the non-significant intervals for significant factors. In addition, the uncertainties in the various steps of the methods are revealed by a ruggedness test.
Ecklonia cava, a species of brown algae, is traditionally used as a foodstuff in Japan and Korea. The phlorotannin components extracted from Ecklonia cava have recently been recognized to possess various biological activities such as antioxidant, anti-inflammatory and anti-carcinogenesis effects. As part of their safety assessment, acute (single dose) and subacute (4-week repeated dose) toxicities were investigated in SD rats using E. cava extracts containing 65% and 20% phlorotannins, respectively. No mortalities or evidence of adverse effects were observed on single oral administration of E. cava extract (65% phlorotannin) at a dose of 2000 mg/kg body weight in SD rats. In a 4-week repeated dose toxicity study, E. cava extract (20% phlorotannin) was orally administrated to SD rats at dose of 0, 222, 667, or 2000 mg/kg/day for 4 weeks. All rats survived until scheduled sacrifice. Compared to the control group, administration of the E. cava extract did not result in any toxicologically significant treatment related changes in clinical observation, body weight gains, ophthalmologic examinations, hematology, coagulation, clinical pathology evaluation and organ weights. Terminal necropsy did not reveal any treatment related gross or histopathology findings. Based on the results of this study, the no-observed-adverse-effect-level (NOAEL) for the E. cava extract was determined as 2000 mg/kg body weight/day, or probably higher dose.
Extensive volatile organic carbons (VOCs) data for a 12-month measurement period, which were collected by the Bureau of the Environment, Tokyo Metropolitan Government, are examined in this study. Behavior of benzene, toluene, ethylbenzene, and xylene was discussed, which were monitored at two specified sampling locations, roadside (Hachimanyama) and residential area (Shirogane) in 2001. The monthly variations of these compounds showed two peaks in June and November. The high concentrations in June were considered to be derived from the unburned and evaporated components of fuel due to raised ambient temperature. On the other hand, atmospheric conditions in Tokyo are generally very stable in November. These conditions would result in the peak in November in monthly variations. The concentrations of benzene and xylene were higher at the roadside than that at residential site. These readings were considered to be strongly influenced by vehicle emissions. The difference between concentrations at the both sites was small with respect to toluene and ethylbenzene. Their sources may be not only vehicles but also some stationary sources. The ratios between m,p-xylene to o-xylene were observed to be constant throughout the year with the exception of June, July, and August only at the residential site.