Mechanisms of Mycotoxin-Induced Neurotoxicity through Oxidative Stress-Associated Pathways

Among many mycotoxins, T-2 toxin, macrocyclic trichothecenes, fumonisin B(1) (FB(1)) and ochratochin A (OTA) are known to have the potential to induce neurotoxicity in rodent models. T-2 toxin induces neuronal cell apoptosis in the fetal and adult brain. Macrocyclic trichothecenes bring about neuronal cell apoptosis and inflammation in the olfactory epithelium and olfactory bulb. FB(1) induces neuronal degeneration in the cerebral cortex, concurrent with disruption of de novo ceramide synthesis. OTA causes acute depletion of striatal dopamine and its metabolites, accompanying evidence of neuronal cell apoptosis in the substantia nigra, striatum and hippocampus. This paper reviews the mechanisms of neurotoxicity induced by these mycotoxins especially from the viewpoint of oxidative stress-associated pathways.     

Evaluation of SOFC anode polarization simulation using three-dimensional microstructures reconstructed by FIB tomography

In order to evaluate the numerical simulation method for solid oxide fuel cell anode polarization, three-dimensional lattice Boltzmann method simulation is carried out using Ni–YSZ microstructures reconstructed by a focused ion beam scanning electron microscope. The effects of reconstructed sample volume size on the three phase boundary length, tortuosity factors and overpotential are first investigated. The YSZ tortuosity factor has remained nearly unchanged when the cross-sectional area exceeds approximately 200 μm², while the pore tortuosity factor is almost independent of the sample volume size. On the other hand, the Ni tortuosity shows very large variation regardless of the sample volume size. The overpotential predicted with the largest volume size sample is slightly larger than those of smaller volume samples. Two exchange current models based on patterned electrodes are assessed presently. Both models give weaker dependence on the steam concentration than the experimental data. From the predicted three-dimensional current stream lines, it is found that the mirrored computational structure gives a thinner reactive layer because of the factitious connection of Ni phase. Thus, it is recommended to use larger volume size samples which can cover whole reactive thickness when discussing the local potential and flux distributions.     

Polymer electrolyte membranes derived from novel fluorine-containing poly(arylene ether ketone)s by controlled post-sulfonation

Precise assignment with ¹H, ¹³C and some two dimensional NMR measurements showed that sulfonation reaction by concentrated sulfuric acid at 30 °C of fluorine-containing poly(arylene ether ketone) copolymers derived from 4,4′-bis(2,4,5,6-pentafluorobenzoyl)diphenyl ether (BPDE) and 9,9-bis(4-hydroxypehnyl)fluorene (HF) and 2,2-bis(4-hydroxyphenyl)-1,1,1,3,3,3-hexafluoropropane (6FBA) yielded quantitative introduction of sulfonic groups onto 2- and 7-positions of fluorene ring in HF unit. A series of sulfonated poly(arylene ether ketone)s with different ion exchange capacity was prepared by using this method with different compositions of HF and 6FBA, and membranes obtained from these polymers were characterized by TGA, moisture and water uptake, proton conductivity, methanol permeability, and Fenton testing. These membranes showed sufficient thermal stability, high proton conductivity at high humidified condition for PEFC and good balance in proton conductivity in water and methanol permeability for DMFC. On the other hand, they showed relatively high swelling by water probably due to weak intermolecular interaction caused by the existence of fluorine atoms in the polymer structure.     

The role of elemental oxygen demand in total oxygen demand for water pollutants

For an advanced evaluation of water pollutants, EOD (elemental oxygen demand) was proposed, and the relation between EOD and TOD (total oxygen demand) was discussed. The EOD was defined as the oxygen demands of each element in the pollutants. A generalized equation of combustion reaction for compounds was proposed. The observed TOD values of various organic and inorganic compounds, except a few inorganic compounds, showed good agreement with the theoretical values calculated from the equation, and the TOD value was the summation of the amounts of EOD by each constituent element. The degrees of COD (carbon oxygen demand), EOD of carbon, and NOD (nitrogen oxygen demand), EOD of nitrogen, in TOD were investigated by using several organic compounds. The ratios of COD/TOD and NOD/TOD were generally above 0.5 and below 0.25, respectively. In an activated sludge pilot plant, the ratio of COD/TOD in influent was 0.76 and that of NOD/TOD 0.075; and in effluent, the NOD/TOD value was larger than the COD/TOD value.     

Benchmark analysis on PFM analysis codes for aged piping of nuclear power plants

Probabilistic fracture mechanics is a rational methodology in structural reliability evaluation and risk assessment for aged piping in nuclear power plants. Several probabilistic fracture mechanical analysis codes have been improved or developed in Japan. To verify the reliability and applicability of two of these codes, we did a benchmark analysis using their basic functions in consideration of representative piping systems in nuclear power plants and typical aging mechanisms. Based on the analysis results, we concluded that the analysis results of these two codes are in good agreement.     

System development and analysis for producing high quality gas and activated sludge char

For energy and resource utilization of dried sewage sludge, an integrated system with in-line connection of pyrolysis gasifier, plasma reformer, and fixed bed adsorber was developed. The plasma reformer was set to improve producer gas yield by destructing tar released from the pyrolysis gasifier. The fixed bed adsorber filled with the sludge char produced from the pyrolysis gasifier was installed for adsorption of un-treated tar. The pyrolysis gasifier produced sludge char, tar and gas. The sludge char showed 98.1 m²/g of specific surface area and 63.49 Å of mean pore size, which had a good distribution of micropore and mesopore with superior adsorption rate of light PAH tar. The concentrations of gravimetric tar and total light tar were 26.3 g/Nm³ and 10.9 g/Nm³, respectively. The analyzed light tar was in the order of benzene, naphthalene, benzonitrile, benzeneacetonitrile, anthracene and pyrene. Produced gas was composed of hydrogen, carbon monoxide, methane, and carbon dioxide. The plasma reformer displayed 83.2% of removal efficiency with 4.4 g/Nm³ of gravimetric tar at the outlet due to tar cracking and steam reforming reaction. The total amount of light tar was 1.3 g/Nm³. Among the reforming gas, the concentration of hydrogen, carbon monoxide, and methane was increased. Gravimetric tar at the outlet of the adsorber was 0.5 g/Nm³, which was 88.6% of removal efficiency. The total amount of light tar was 0.39 g/Nm³. Gas analysis results at the exit showed 50.5% H₂, 21.9% CO, 10.5% CH₄, 7.7% CO₂ and 0.1% C₂H₂ with a higher heating value of 13,482 kJ/Nm³. Therefore, sewage sludge can be converted into energy and resource by pyrolysis and gasification since the producer gas and sludge char could be utilized in a heat engine and adsorption tower for tar removal, respectively.

     

Kluyveromyces marxianus-based platform for direct ethanol fermentation and recovery from cellulosic materials under air-ventilated conditions

Consolidated bioprocessing represents an attractive approach to converting cellulosic materials into bioethanol, yet is practically unavailable. We developed a ventilation-mediated, simultaneous ethanol fermentation and recovery system. Running the system under air-supplied conditions, apparently pure ethanol (28g) was recovered from cellobiose (100g) by growing recombinant Kluyveromyces marxianus expressing β-glucosidase.     

Solid circulation rate in a circulating fluidized bed in the presence of fine powders

Fine powders (Geldart's group C) are added to a circulating fluidized bed (CFB) of coarse particles (Geldart's group A) and the solid circulation rate (SCR) is investigated with addition of fine powders of different sizes and different fractions (different hold-ups) to the bed. Experiments were carried out in a CFB of 2 m in height and 0.052 m in diameter, using FCC catalyst particles of as the coarse particles and cohesive aluminum hydroxide powders of 0.5- as the fine powders. The effects of hold-up of fine powders in the bed, fine powders size, and superficial gas velocity on the SCR were investigated.The SCR strongly depended on the hold-up of fine powders of 0.5- in size and noticeably decreased with increasing the hold-up of fine powders under constant gas velocity. This dependency disappeared when the size of fine powders was larger than . Thus, depending on the size of fine powders added to the CFB, two distinct regions for the changes of SCR could be clearly identified.     

Changes of aquaporin 5-distribution during release and reaccumulation of secretory granules in isoproterenol-treated mouse parotid gland

Water channel aquaporin 5 (AQP5) is present in the apical membrane of the salivary gland acinar cells. We examined changes of AQP5-distribution during the fusion process of secretory granule membranes into the apical membrane and subsequent recovery process in the mouse parotid gland by administering isoproterenol (IPR) in vivo. We performed immunoperoxidase, immunofluorescence and immunoelectron microscopy. In the basal state, AQP5 was localized mainly in the apical membrane of the acinar cell. It was also present in the basolateral membrane to a lesser extent. When IPR was administered to mice, dot-like, vesicle-like and vacuole-like labeling for AQP5 was seen in the subapical regions by light microscopy. By immunoelectron microscopy, AQP5 was localized at both the apical and basolateral plasma membranes in the basal state. At 5 and 30 min after the IPR-administration, acinar lumen became enlarged and small invaginations formed by fusion of secretory granules were seen. AQP5 was positive along the apical plasma membrane and its small invaginations. At 60 min, large invaginations of the lumen were formed. AQP5 remained positive in the membrane of these large invaginations. At 6 h, large invaginations disappeared and AQP5 was localized in the apical plasma membrane. AQP5 was restricted to plasma membranes and continuous invaginations formed by the exocytosis of secretory granules. AQP5 was not detected in the cytoplasm. These observations show that AQP5 does not seem to be endocytosed during the membrane recycling process following the exocytosis.