Biodegradation of n-alkylcyclohexanes by co-oxidation via multiple pathways in Acinetobacter sp. ODDK71

The degradation of alkylcyclohexane by Acinetobacter sp. ODDK71 was investigated. Strain ODDK71 degraded alkylcyclohexanes (alkyl side chain length of > or = 12) by co-metabolism when hexadecane was used as a growth substrate. GGMS analysis of co-metabolized products from dodecylcyclohexane suggests that strain ODDK71 degraded dodecylcyclohexane via a ring oxidation and an alkyl side chain oxidation pathways. The ring oxidation pathway of dodecylcyclohexane is a novel pathway of microbial degradation of dodecylcyclohexane.     

Numerical analysis of the single electrode heat effect in molten carbonate fuel cells: temperature analysis of the electrolyte plate by applying irreversible thermodynamics

A temperature analysis model of a molten carbonate fuel cells (MCFC) stack is used to calculate the single electrode heat effects. The magnitude of heat which evolves from the cathode and absorbed at the anode is large, and in similar value to the electrical output of a MCFC. This suggests that the heat evolution of a single electrode causes a temperature difference between the electrodes. The temperature distribution in the electrolyte plate is evaluated to establish more accurate results concerning the temperature analysis model of the stack. The temperature distribution in the electrolyte plate is studied by applying irreversible thermodynamics. When the operating current density is less than 3000 A m^?2 and the thermal conductivity of the electrolyte is more than 2 W m^?1 K^?1, the temperature difference between cathode and anode is estimated to be less than approximately 1 K. This result proves that the temperature difference between the electrodes can be supposed constant in constructing the temperature analysis model of the MCFC stack. This results also allows us to construct a two‐dimensional heat production distribution in the cell plane and discrete heat production distribution in the stacking direction for the practical use of the temperature analysis model. Copyright © 2004 John Wiley & Sons, Ltd.     

Modeling of the simulated moving-bed reactor for the enzyme-catalyzed production of lactosucrose

The enzyme-catalyzed production of lactosucrose in a simulated moving-bed reactor is investigated. A numerical model is derived and verified by data obtained from simulated moving-bed reactor experiments. Based on the derived model, parameter studies and optimization are carried out. It is found that along with the flow rate settings, substrate feed and enzyme concentration and thermal deactivation of enzyme strongly influenced the product yield. Simulation showed that despite of parallel and consecutive side reaction, the maximum lactosucrose yield can reach 69%, which represents a yield increase of 36% relative to the equilibrium yield.     

Assessment of the effect of fermented papaya preparation on oxidative damage in spontaneously hypertensive rat brain using electron spin resonance (ESR) imaging and L-band ESR spectroscopy

Oxidative and nitrosative stress mechanisms are widely implicated in the biological and pathological processes involved in aging, cardiovascular and neurodegenerative diseases. Although this has continued to fuel suggestions of the benefits of antioxidant functional foods, in vivo methods for assessing the integrity of this remain limited. A novel electron spin resonance (ESR) technique for evaluating oxidative stress and location of its damage in the brain of spontaneously hypertensive rats (SHR) has been described [Lee, M.-C., et al. (2004). Assessment of oxidative stress in the SHR brain using electron spin resonance (ESR) imaging and in vivo L-Band ESR. Hypertension Research, 27, 485–492]. The reconstructed 2D ESR images of the distribution of a blood brain barrier-permeable nitroxyl spin probe, 3-methoxycarbonyl-2,2,5,5-tetramethylpyrrolidine-1-oxyl (MC-PROXYL) was used to investigate the ability of fermented papaya preparation (FPP, a product of yeast fermentation of Carica papaya Linn.) to modulate oxidative stress of SHR brain. Supplementation (5–7 months) with FPP (50 mg/rat/day) significantly increased the decay of the ESR images of the MC-PROXYL, suggesting that FPP may have up-regulated the redox defense activity in the SHR brain. Herein is an in vivo noninvasive technique for the study of oxidative stress and its modulation by dietary factors (that may be intended for applications as neuroprotectants in chronic degenerative disease involving loss of brain function).     

Explaining media choice: theoretical discussion and an empirical experiment

The paper is based on a review of research on media selection and related topics on the one hand and on an explorative pilot survey on the other. In summarising the review, the authors propose that the factors explaining media choice be grouped into five categories: (1) the properties of the media itself affect its choice, (2) properties of the user affect media choice, (3) the communication situation plays an important role, (4) macro factors explain media choice, and (5) media choice can be explained as the outcome of a dynamic multiparty negotiation process. The pilot survey compares Japanese and Finnish students’ preference of media in various communication situations. The survey results encourage reserving, local macro factors or culture, a certain amount of explanatory force in explaining media choice.     

Surface decontamination of fig fruit by combination of infrared radiation heating with ultraviolet irradiation

The application of single and sequential treatments of infrared radiation (IR) heating and ultraviolet (UV) irradiation to surface decontamination was investigated in relation to extending the shelf life of fig fruits. In addition, the inactivation effects of IR heating or UV irradiation, and their sequential treatments on fig fruit related yeast were also investigated. The sequential treatment of IR heating and UV irradiation was effective in the surface decontamination of fig fruits. The fungal counts detected after sequential treatments were lower than those obtained after a single treatment or in control samples. The number of fruits damaged by the growth of mold and yeast was also reduced after 30 s IR heating followed by 30 s UV irradiation. The sequential treatment was found to be highly suitable for decontamination of fig fruit surface, since few unfavorable effects were observed with regard to the surface color, hardness score, and respiration of fruits during storage. Single treatment with IR heating or UV irradiation had little effect on the inactivation of isolated Rhodotorula mucilaginosa cells. However, R. mucilaginosa cells were successfully inactivated by sequential treatment with IR and UV. The killing efficiencies appeared to be independent of the order in which IR heating and UV irradiation were applied to the samples. It was hypothesized that the DNA damage caused by UV irradiation and the inhibition of its repair might be enhanced by the thermal energy of IR heating to a sub-lethal level, since the temperature monitored during IR heating was considerably lower than the lethal level of R. mucilaginosa cells.     

Electrically conducting suspensions formed by polyaniline

Polyaniline was synthesized with the chemical oxidation in the presence of poly(vinylpyrrolidone) as a surfactant for small-sizing polyaniline grains. It was dispersed in glycerin including sulfuric acid to yield electrically conducting solution. Voltammograms of the solution by the two-electrode measurement showed the proportionality of the Ohm's law in the cell voltage from −0.2 to 0.2 V. Voltammograms by the three-electrode measurement in the domain 0.0-1.5 V versus Ag|AgCl were different from the Ohmic law and Faradaic current of polyaniline, because of a mixture of both the contributions. The conductance did not vary with the volume fraction of polyaniline up to 20% and enhanced drastically until 35% with large fluctuation, and then increased proportionally with the volume fraction. This variation was explained in terms of the electric percolation with a threshold at the volume fraction of 20-35%. The mixture with over 45% fraction was actually solid. The suspension was applied to confirming the relation between the Ohmic current at a microelectrode and its diameter. The current showed a linear relation with the electrode diameter with a small intercept of the diameter, of which value corresponded to the size of polyaniline grains.