Simple Method for Measuring the Peroxide Value in a Colored Lipid

We developed a simple method for quantification of the peroxide value (PV) in colored lipids on the basis of the reaction between triphenylphosphine (TPP) and oxidized oil to afford triphenylphosphineoxide (TPPO). Diphenylphosphineoxide (DPPO) was employed as internal standard. The formed TPPO was analyzed by high-pressure liquid chromatography–UV spectroscopy with absorption at 260 nm. The conditions that gave the highest correlative calibration curve between the peak area on the chromatogram and peroxide value were identified: the optimum TPP–oxidized oil mix ratio, reaction temperature, and reaction time were found to be 2:1, 40 °C, and 30 min, respectively. Linear calibration curves, passing through the origin, were obtained for PV versus TPPO and TPPO versus DPPO. The quantification limit for this method was 2.01 pmol hydroperoxyl group, which corresponds to a PV value of 0.2 meq/kg in a 10-mg oil sample. This method was used to measure the PV in colored fats and oils or lipids extracted from dark meat and processed food containing a coloring agent. Though the official method could not measure the PVs in the colored lipids, the method proposed here, which uses an inexpensive chemical reagent and machine, could. The developed method could play an important role for food quality control.     

Sensitivity and Evaluation of Explosive Substances

Explosion sensitivity involves many complex factors. A theory for evaluating and a method for testing have to be established. We have proposed an explosion sensitivity theory for explosive substances and have also tested the evaluating method. The results of our research reveal a satisfactory mutual relation between both theoretical and experimental values.     

Fabrication of bilayered YSZ/SDC electrolyte film by electrophoretic deposition for reduced-temperature operating anode-supported SOFC

Bilayered Y₂O₃-stabilized ZrO₂ (YSZ)/Sm₂O₃-doped CeO₂ (SDC) electrolyte films were successfully fabricated on porous NiO–YSZ composite substrates by electrophoretic deposition (EPD) based on electrophoretic filtration followed by co-firing with the substrates. In EPD, positively charged YSZ and SDC powders were deposited directly on the substrates, layer by layer from ethanol-based suspensions. Delamination between YSZ and SDC films was avoided by reducing the SDC films’ thickness to ca. 1 μm. A single cell was constructed on the bilayered electrolyte films composed of ca. 4 μm-thick YSZ and ca. 1 μm-thick SDC films. As a cathode in the cell, La_0.6Sr_0.4Co_0.2Fe_0.8O_3−x (LSCF) was used. Maximum output power densities greater than 0.6 W cm⁻² were obtained at 700 °C for the bilayered YSZ/SDC electrolyte cells thus constructed.     

Sillimanite‐mullite transformation observed in synchrotron X‐ray diffraction experiments

High‐resolution synchrotron powder X‐ray diffraction (XRD) experiments were conducted to clarify the transformation of sillimanite to mullite (mullitization) and determine the mullitization temperature (T_c). We were able to distinguish sillimanite and mullite in the XRD patterns, despite their very similar crystallographic parameters, and to detect the appearance of small mullite peaks among sillimanite peaks. Analysis of the Johnson‐Mehl‐Avrami (JMA) equation for mullitization ratio (ζ) revealed that at temperatures T≥1240°C the mullitization had the same kinetics. The activation energy E at T≥1240°C obtained from the Arrhenius plot was 679.8 kJ mol^?1. In analysis using a time‐temperature‐transformation diagram for mullitization, a mullitization curve of ζ=1% can be described as where t is time, n is a reaction‐mechanism‐dependent parameter determined as 0.324 by JMA‐analysis, k₀ is the frequency factor, E_A is the activation energy for atomic diffusion, and represents the activation energy for nucleation. The results of fitting the data to this equation were T_c=1199°C, A=3.9×10⁶ kJ mol^?1 K^?2, E_A=605 kJ mol^?1, and k₀=3.65×10¹⁵. We conclude that the boundary between sillimanite and mullite+SiO₂ in the phase diagram is ~1200°C.     

On the natural structure of thermodynamic potentials and fluxes in the theory of chemically non-reacting binary mixtures

A theory describing the behavior of chemically non-reacting binary mixtures can be based on a detailed formulation of the governing equations for the individual components of the mixture or on treating the mixture as a single homogenized continuous medium. We argue that if we accept that both approaches can be used to describe the behavior of the given mixture, then the requirement on the equivalence of these approaches places restrictions on the possible structure of the internal energy, entropy, Helmholtz potential, and also of the diffusive, energy, and entropy fluxes. (The equivalence of the approaches is understood in the sense that the quantities used in one approach can be interpreted in terms of the quantities used in the other approach and vice versa. Further, both approaches must lead to the same predictions concerning the evolution of the physical system under consideration). In the case of a general chemically non-reacting binary mixture of components at the same temperature, we show that these restrictions can indeed be obtained by purely algebraic manipulations. An important outcome of this analysis is, for example, a general form of the evolution equation for the diffusive flux. The restrictions can be further exploited in the specification of thermodynamically consistent constitutive relations for quantities such as the interaction (drag) force or the Cauchy stress tensor. As an example of the application of the current framework, we derive, among others, a generalization of Fick’s law and we recover several non-trivial results obtained by other techniques. The qualitative features of the derived generalization of Fick’s law are demonstrated by a numerical experiment.     

Formate protects photosynthetic machinery from photoinhibition

In plants, environmental adversity often leads to the formation of reactive oxygen species (ROS) because of excess light energy. We found that incubation of rice leaves under high light intensity together with CO2-depleted air seriously damaged photosynthesis; however, the application of potassium formate (2 mM) before the photoinhibitory treatment protected the photosynthesis of the plant from photoinhibition. Further analysis revealed that formate protects PSII, RuBisCO, and FBPase from photoinhibition. Formate is thought to be involved in endogenous radical scavenging and/or in the supply of CO2, derived from the formate, thereby reducing oxidative damage to the photosystems under photoinhibitory conditions.     

Molecular cloning and characterization of a novel bacteriophage-associated sialidase

Bacteriophage 63D, previously isolated from sewage, is associated with alpha-2,8-linked polysialic acid degrading activity. We cloned a DNA fragment containing the sialidase gene from a 63D phage genomic library and the enzyme was functionally expressed in Escherichia coli. Determination of the nucleotide sequence of the fragment revealed that it contained one open reading frame (ORF) coding for a 108-kDa polypeptide consisting of 984 amino acid residues. The fragment had promoter sequences similar to the E. coli consensus promoters for sigma70. The deduced amino acid sequence of the central region of the ORF showed homology to those of phages K1F (51.6% identity) and PK1E (51.7% identity) endosialidases. Two Asp-box motifs that are widely found in sialidases were conserved. Purification of the soluble enzyme from lysed culture broth of infected E. coli yielded a 90-kDa protein upon SDS polyacrylamide gel electrophoresis, suggesting that the primary translational product is processed to the mature 90-kDa protein. The molecular mass of the enzyme was determined as 360 kDa by gel filtration, indicating that the native enzyme was probably a tetramer of identical 90-kDa subunits.