Ultra-high pressure sterilization of powdery food stuff—a new application of a roller compactor

A new non-heating technique was developed for the sterilization of food stuff. Applying a roller compactor, ultra-high pressure sterilization has experimentally demonstrated its ability to sterilize dry powders, such as corn flour and Chinese herbs, with little quality deterioration. Also, the degree of food sterilization was found correlated well with the linear press forces between the rollers, roller gaps, and number of compaction passes. In comparison to the conventional high pressure sterilization technique, the new dry continuous processing method has the advantage of lower investment cost and is more versatile for sterilizing various food powders.     

Photocatalysts using hexa- and octa-titanates with different tunnel space for water decomposition

Photocatalytic activities for water decomposition were examined for photocatalysts using hexa- and octa-titanates and TiO2(B) with different tunnel space in the structure. Using RuO2 as promoter, M2Ti6O13 (M = Li, Na, K, Rb) showed the stoichiometric production of Hz and O₂ except for Li, whereas H₂Ti₈O₁₇ and TiO₂(B) had very low activity producing only hydrogen as a product. The effects of promoters on Na₂Ti₆O₁₃ showed that the activity increased in the order of RuO₂ > RuO₂ + IrO₂ > IrO₂ > RuO₂ + Pt > MnO₂. These effects along with other related ones are discussed: it emerges that the presence of the tunnels is important for the achievement of high photocatalytic activity.     

Performance of solvothermally prepared Ga2O3-Al2O3 catalysts for SCR of NO with methane

The solvothermal reaction of mixtures of aluminum isopropoxide (AIP) and gallium acetylacetonate (Ga(acac)₃) directly yielded the mixed oxides of γ-Ga₂O₃-Al₂O₃. In the solvothermal synthesis, the crystal structure of mixed oxides was controlled by the initial formation of γ-Ga₂O₃ nuclei. The mixed oxides prepared in diethylenetriamine have extremely high activities for selective catalytic reduction (SCR) of NO with methane as a reducing agent. With increasing crystallite size of the spinel structure, the catalytic activity increased. The ratio of the amount of methane consumed by combustion to total methane conversion was proportional to the density of acid sites on the surface of the mixed oxides. The mixed oxide catalysts prepared in diethylenetriamine had lower densities of acid sites and showed a higher methane-efficiency for CH₄-SCR than those prepared in other solvents. These catalysts maintained their high activity even when the reaction was carried out under the severe conditions (i.e., high space velocity and low NO concentration).     

Thermotropic polyarylates derived from substituted hydroquinones and p-terphenyl-4,4″-dicarboxylic acid

Polyarylates from substituted hydroquinones (HQs) and p-terphenyl-4,4″-dicarboxylic acid (TPDA) that were modified with 1,2-bis(phenoxy)ethane-4,4′-dicarboxylic acid (PEC), 1,2-bis(2-chlorophenoxy)ethane-4,4′-dicarboxylic acid (ClPEC), terephthalic acid (TA) and p-hydroxybenzoic acid (HBA) were prepared and their thermal and mechanical properties were investigated. These polyarylates exhibited liquid crystallinity at about the same temperatures as polyarylates derived from substituted HQs and 4,4′-diphenyldicarboxylic acid (BB). However, as-spun fibers and injection-molded specimens of these polyarylates exhibited lower moduli than those of substituted HQs and BB that were modified with PEC, Cl-PEC and TA.     

Lysozyme requires fluctuation of the active site for the manifestation of activity

Mutations around His15 which lie far away from the active site,stimulated glycol chitin activity of lysozyme at physiologicaltemperature. Del-Argl4Hisl5 lysozyme, a mutant lysozyme whoseArgl4 and Hisl5 were deleted together, and has the highest activityamong these mutant lysozymes, had a similar binding abilityto a trimer of N-acetyl-glucosamine, a substrate analogue, relativeto native lysozyme. This suggests that the increased activitywas due to an increased k_cat in the catalysis reaction. TheH-D exchange rate of the N-1 proton in the Trp63 which is locatedin the active site cleft, was enhanced in the Del-Argl4Hisl5lysozyme, while 2-D proton NMR analysis revealed no conformationalchange around Trp63. We conclude that some sort of fluctuationat the active site might be required for the manifestation ofactivity. This theory is supported by the finding that the Del-Argl4Hisl5lysozyme showed a shift in temperature dependency of activityto lower temperatures compared with that of native lysozyme.     

Interactions oftrans-cinnamic acid,its related phenolic allelochemicals,and abscisic acid in seedling growth and seed germination of lettuce

Phenolic compounds have been identified as the most common allelochemicals produced by higher plants. Inhibitions of cinnamic acid, its related phenolic derivatives, and abscisic acid (ABA) on seedling growth and seed germination of lettuce were studied.trans-Cinnamic acid, ando-,m-, andp-coumaric acids inhibited the growth of etiolated seedlings of lettuce at concentrations higher than 10^–4 M and seed germination above 10^–3 M. Coumarin inhibited seedling growth and seed germination at 10^–5 M or above. Chlorogenic acid inhibited seedling growth above 10^–4 M, but did not inhibit seed germination at 10^–5–5×10^–3 M. Low concentrations (below 10^–3 M) of caffeic and ferulic acids promoted the elongation of hypocotyls, but higher concentrations (over 10^–3 M) inhibited seedling growth and seed germination. These phenolic compounds and abscisic acid had additive inhibitory effects both on seedling growth and seed germination. The inhibition on lettuce was reversed by caffeic and ferulic acids at concentrations lower than 10^–3 M except for the inhibition of germination by coumarin. These results suggest that in naturetrans-cinnamic acid,o-, m-, p-coumaric acids, coumarin, and chlorogenic acid inhibit plant growth regardless of their concentration. However, caffeic and ferulic acids can either promote or inhibit plant growth according to their concentration.     

Guinea pig bone marrow cells treated with platelet-activating factor generate factor(s) which affects their DNA synthesis and microbicidal activity

We have previously reported that platelet-activating factor (PAF) induces proliferation and microbicidal activity of guinea pig bone marrow cells. In the present study, we have found that the conditioned medium of PAF- or nonmetabolizable PAF agonist-treated guinea pig bone marrow cells augmented DNA synthesis and induced microbicial activity of bone marrow cells. A PAF specific antagonist, CV-6209, inhibited generation of the active conditioned medium by PAF. Addition of the PAF antagonist only partially suppressed the augmentative effect of the active conditioned medium on DNA synthesis; this is consistent with the fact that, because of the rapid breakdown, no appreciable amount of PAF remained in the conditioned medium of PAF-treated cells. Although mouse bone marrow cells did not respond to PAF unlike guinea pig cells, their DNA synthesis was significantly enhanced by the conditioned medium of PAF-treated guinea pig bone marrow cells. Thus, some newly generated factor(s) distinct from the originally inoculated PAF seemed to modulate the bioactions of PAF on bone marrow cells. An appreciable amount of PAF was produced by calcium ionophore-treated guinea pig bone marrow cells. These findings indicate that PAF synthesized in guinea pig bone marrow cells induces generation in the cells of some factor(s) which affects proliferation or microbicidal activity. Presented at The Third International Conference on Platelet-Activating Factor and Structurally Related Ether Lipids, Tokyo, Japan, May 1989.     

Sterols ofKalanchoe pinnata: First report of the isolation of both C-24 epimers of 24-alkyl-Δ25-sterols from a higher plant

Eighteen sterols were isolated from the aerial parts ofKalanchoe pinnata (Crassulaceae) including four novel sterols,viz. (24R)-stigmasta-5,25-dien-3β-ol (24-epiclerosterol), (24R)-5α-stigmasta-7,25-dien-3β-ol, 5α-stigmast-24-en-3β-ol, and 25-methyl-5α-ergost-24(28)-en-3β-ol. 24-Epiclerosterol and its Δ⁷-analog occur together with their 24S/β-epimers in the same plant making this the first report of the isolation of both C-24 epimers of Δ²⁵-unsaturated 24-alkylsterols from a non-marine organism. Iodine-catalyzed isomerization of stigmasta-5,24-dien-3β-ol (24-ethyldesmosterol), the main sterol ofK. pinnata, yielded 24-epiclerosterol among other products.     

Synthesis of γ-Ga2O3–Al2O3 Solid Solutions by the Glycothermal Method

The reaction of mixtures of aluminum isopropoxide and gallium acetylacetonate in 1,4-butanediol or 1,5-pentanediol at high temperatures (glycothermal reaction) directly gave the γ-Ga₂O₃–Al₂O₃ solid solutions, which had high catalytic activities for selective reduction of NO using methane as the reducing agent. However, the reaction with a higher Al/(Ga+Al) charged ratio yielded the glycol derivative of boehmite as a by-product and the catalytic activity of the solid solution decreased. Therefore, synthesis of the solid solution using various glycols was examined and it was found that solid solutions with high Al contents without contamination of the glycol derivative of boehmite were obtained by using 1,6-hexanediol as a reaction medium. The solid solution exhibited a higher NO conversion than that synthesized in other glycols.     

Heat transfer to laminar flow with temperature — dependent heat generation

Two problems were solved theoretically on the heat transfer to circular tube flow with internal heat source. The one problem is to maintain the mixed-mean temperature of fluid at the inlet temperature. The other is a conjugated problem with a uniformly specified temperature at the outside surface of the wall, accounting for the wall conduction. From the numerical example for the former, it is shown that the mixed-mean temperature can be controlled within 15% error under the estimated condition. From the numerical results for the latter, it is concluded that the influence of wall conduction is more serious than the case without heat generation.