Ozone decomposition of 2-methylisoborneol (MIB) in adsorption phase on high silica zeolites with preventing bromate formation

This work elucidates the applicability of our newly developed adsorptive ozonation process for the decomposition of 2-methylisoborneol (MIB), a typical taste and odor chemical, without the formation of possibly carcinogenic bromate ions. First, zeolite adsorbents were screened for their ability to adsorb MIB with a batch-type adsorption experimental apparatus and a flow-type decomposition experimental apparatus included an adsorbent-packed column. The USY zeolite with the highest silica to alumina ratio (SiO(2)/Al(2)O(3) molar ratio=70) showed the best performance as an adsorbent. Using this adsorbent, an ozonation experiment on an MIB solution including bromide ions was performed under various retention times using the flow-type apparatus. As a result, sufficient decomposition of MIB was achieved with preventing bromate formation.     

Electron Transfer in Ferrocene-containing π-conjugated Polymers

We describe here our recent research on -conjutgated organometallic polymers containing ferrocenyl groups. Internuclear electronic interactions through the -conjugated spacer display unique redox and optical properties. The dependence of the redox properties on the number of ferrocene moieties in oligo(1,1-ferrocenylene)s were analyzed by the neighboring-site interaction model. The electronic structure in the mixed-valence states of biferrocene and terferrocene were estimated using the infrared (IR) spectra. Intervalence-transfer (IT) bands in the mixed-valence states of oligo(1,1-ferrocenylene)s were rationalized by taking into account the change in neighboring-site interaction by photo-electron transfer. Near-IR photoconductivity was found for the charge transfer complex of oligo- and poly-(1,1-ferrocenylene)s with tetracycanoethylene (TCNE). Redox and optical properties of azo-bridged ferrocene oligomers and a polymer was also analyazed based on the neighboring-site interaction model. Metallacyclization reaction of para-bis(ferrocenylethynyl)benzene with CpCo(PPh₃)₂ affforded a ferrocene-containing cyclobutadienecobalt polymer, of which redox property indicates strong intra-unit and weak inter-unit interactions.     

Isolation of a CDC25 family gene,MSI2/LTE1, as a multicopy suppressor of ira1

We have identified MS12 as a gene of Saccharomyces cerevisiae which, when on a multicopy vector, suppresses the heat shock sensitivity caused by the loss of the IRA1 product, a negative regulator of the RAS protein. The multicopy MSI2 also suppresses the heat shock sensitivity of cells with the RAS2^val19 mutation but not those with the bcy1 mutation, suggesting that the MSI2 protein may interfere with the activity of the RAS protein. The sequence analysis of MSI2 reveals that it is identical to LTE1 belonging to the CDC25 family: CDC25, SCD25 and BUD5, each of which encodes a guanine nucleotide exchange factor for the ras superfamily gene products. Deletion of the entire MSI2 coding region reveals that MSI2 is not essential but the disruptant shows a cold-sensitive phenotype. Under the non-permissive conditions, more than 70% of the msi2 disruptants arrested at telophase as large budded cells with two nuclei divided completely and elongated spindles, indicating that the msi2 deletion is a cell division cycle mutation. These results suggest that MSI2 is involved in the termination of M phase and that this process is regulated by a ras superfamily gene product.     

Synthesis and properties of destructible anionic and cationic surfactants with a 1,3-dioxolane ring

A convenient synthetic method for the preparation of destructible surfactants containing a 1,3-dioxolane ring with various substituents is described. The substituents include carboxylate, quaternary ammonium, and several aliphatic alkyl groups, such as hydrophilic or hydrophobic groups. These novel surfactants had good surface activity, and were easily hydrolyzed under acidic conditions. They also catalyzed aliphatic halide substitution.     

Stable expression and characterization of human PN1 and PN3 sodium channels

Nociceptive transduction in inflammatory and neuropathic pain involves peripherally expressed voltage-gated sodium channels, such as tetrodotoxin (TTX)-sensitive PN1 and TTX-resistant PN3. We generated recombinant cell lines stably expressing the human PN1 and PN3 sodium channels in Chinese hamster ovary (CHO) cells using inducible expression vectors. The PN1 and PN3 cDNAs were isolated from human adrenal gland and heart poly(A)+ RNAs, respectively. The recombinant human PN1 currents exhibited rapid activation and inactivation kinetics and were blocked by TTX with a half-maximal inhibitory concentration (IC50) of 32.6 nM. The human PN3 channel expressed in stable transfectants showed TTX-resistant inward currents with slow inactivation kinetics. The IC50 value for TTX was 73.3 microM. The voltage-dependence of activation of the PN3 channel was shifted to the depolarizing direction, compared to that of the PN1 channel. Lidocaine and mexiletine exhibited tonic and use-dependent block of PN1 and PN3 channels. The PN1 channel was more susceptible to inhibition by mexiletine than PN3. These results suggest that stable transfectants expressing the human PN1 and PN3 sodium channels will be useful tools to define subtype selectivity for sodium channel blockers.     

Quantitative analysis of surface atom positions in a thick crystal as determined by a reconstructed exit wave

Atomic structures of an Au (110) 2 x 1 reconstructed surface were analysed quantitatively using an exit wave reconstructed by the three-dimensional Fourier filtering method in high-resolution transmission electron microscopy. To reconstruct the exit wave in a relatively thick crystal, a practical criterion was proposed in the present analysis. In the 'pseudo-exit wave' obtained by the proposed criterion, relaxation of surface atoms was clearly visible in the top three layers. The atoms' displacement was measured to be about 5-20 pm. For quantitative analysis of the atom column positions, image contrast calculations were performed using a structural model of the Au (110) reconstructed surface. Calculations confirmed that the reconstructed pseudo-exit wave could represent the atom column positions directly with an accuracy of several pm, even for a relaxed surface, provided the sample thickness was <7 nm.     

Biological characteristics of the junctional epithelium

This review summarizes the biological properties of the junctional epithelium, focusing on its developmental aspects, wide intercellular spaces and desmosomes, dense granules, permeability barrier, phagocytotic activity, adhesive structures and nerve terminals. It also discusses the morphology and functions of long junctional epithelium and peri-implant epithelium. Junctional epithelium is derived from the reduced enamel epithelium during tooth development. Apoptosis occurs in the border between oral and reduced enamel epithelia during tooth eruption. Junctional epithelium expresses a cytokeratin-19 immunoreaction, suggesting that this protein is a consistent differentiation marker. Wide intercellular spaces, which contain neutrophils and nerve endings, are formed as there are fewer desmosomes than in the oral epithelium. Dense, membrane-bound granules in the epithelium might correspond with membrane-coating granules, as revealed by their shape, components and freeze-fracture images. Junctional epithelium with high permeability contains exogenously expressed alpha-defensins, while stratified epithelia contain endogenously expressed beta-defensins. The phagocytotic activity in this epithelium remains unclear. Integrin-alpha6beta4 and laminin-5 form a complex in the tooth surface internal basal lamina. Long junctional epithelium created experimentally attaches to the cementum surface by hemidesmosomes and basal lamina. The peri-implant epithelium differs in proliferation and in adhesive structure from the normal junctional epithelium. In conclusion, wide intercellular spaces and poorly developed desmosomes are closely correlated with a permeable nature. There is still uncertainty over the phagocytotic activity of the epithelium. Integrin-alpha6beta4 and laminin-5 form a significant complex in the internal basal lamina. Junctional epithelium receives a rich sensory nerve and has a high rate of cell turnover. Long junctional epithelium can be produced rapidly during wound healing, due to high proliferative activity. Peri-implant epithelium might be a poorly adhered and permeable epithelium.     

Perception of complex geometric figures in chimpanzees (Pan troglodytes) and humans (Homo sapiens): Analyses of visual similarity on the basis of choice reaction time.

In a conditional-discrimination task (matching-to-sample), assessed similarities among figures consisting of 2 elemental figures through the choice reaction time (RT), nonmetric multidimensional scaling, and hierarchical cluster analysis of data from chimpanzees (Pan troglodytes) and humans (Homo sapiens). Humans also rated similarities among figures. The results of the 3 experiments clearly indicated that the RT data obtained from chimpanzees' performances were useful measures of the similarities among figures. The results suggested that chimpanzees and humans perceived the complex figures similarly. The outer-contour elements were perceived most dominantly by both species, and the straight-line elements were perceived least dominantly. Both species showed the same perceptual hierarchy or dominance among perceptual categories, as determined by the similarity of simple elements, on the basis of transformational invariances. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Temperature-dependence mechanism of tensile strength of Si-Ti-C-0 Fiber-Aluminum matrix composites

The mechanism for the temperature dependence of the tensile strength of unidirectional hybrid type Si-Ti-C-O (Tyranno) fiber-reinforced aluminum matrix composite, in which SiC-particles are dispersed in the matrix, is discussed, focusing on the temperature dependencies of the stress concentration arising from broken fibers and critical length and their influences on the composite strength, by means of a shear-lag analysis and a Monte Carlo simulation. The main results are summarized as follows. The softening of the matrix at high temperatures raises the composite strength from the point of decrease in stress concentration, but on the other hand, it also reduces strength from the point of increase in critical length, which reduces the stress-carrying capacity of broken fibers over a long distance. The reason why the measured strength of composite decreased with increasing temperature could be attributed to the predominacy of the latter effect over the former one. The results of the simulation indicated that the hybridization of the composites improved room-temperature and high-temperature strengths through the strengthening of the matrix.     

Ozone fading of phenolphthalein and aurin

The reactions of phenolphthalein, which exists as a lactone-quinonoid tautomeric mixture in solution, and aurin with ozone have been examined. The reactivity of the lactone tautomer of phenolphthalein with ozone was found to be low and the ozone attacks the aromatic ring. In the case of the quinonoid tautomer the ozone readily reacts with the carbon skeleton. In the case of aurin ozone also attacks the carbon skeleton.