Measurement of High-Temperature Elastic Properties of Ceramics Using a Laser Ultrasonic Method

Young's modulus and Poisson's ratio of SiC ceramics at temperatures >1400°C were obtained using a laser ultrasonics method that included a Fabry-Pérot interferometer (LUFP). At temperatures <1000°C, Young's modulus and Poisson's ratio measured using the LUFP method agreed well with those measured using standard contact methods, such as the resonance method and the ultrasonic pulse method. These results showed that the LUFP method is a powerful tool for measuring high-temperature elastic properties of advanced ceramics in a noncontact manner.     

Regeneration characteristics of desiccant rotor with microwave and hot-air heating

Microwave heating, because of its advantages of direct and rapid heating of materials, has the potential to be employed as a novel regeneration method of desiccant rotors in humidity conditioners. We proposed a combined regeneration process, which combines microwave heating and conventional hot-air heating. The system is expected to achieve high heating rate during an initial regeneration period by assisting water desorption using the additional energy of the microwave. In this study, the regeneration characteristics of a desiccant rotor were experimentally investigated under conditions of microwave heating, hot-air heating, and combined heating at various microwave powers and hot-air temperatures. The effectiveness of the combined regeneration was evaluated in terms of the regeneration ratio, the initial regeneration rate, the temperature distribution in the rotor, and finally in terms of the energy consumption. It was demonstrated that combined heating was effective at leveling non-uniform temperature distribution in the rotor. Combined heating achieved higher ratios and initial rates in regeneration compared to just microwave and hot-air heating. This result was obviously attributed to the additional input of microwave energy, resulting that average rotor temperature increased by microwave absorption of rotor. Moreover, it was also effective for enhancement of regeneration to level the temperature distribution in the rotor by combination of two heating methods with different heating mechanisms. Both the initial regeneration rate and the equilibrium regeneration ratio for combined heating were found to increase as the microwave power increased. A linear relationship was observed with respect to microwave power. From the viewpoint of energy consumption, it may be possible to apply combined and microwave heating to humidity control systems that switch between adsorption and regeneration in short cycle times, if the conversion and absorption efficiencies of the microwave are significantly improved.     

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.     

Immunomodulatory effect of mushrooms on cytotoxic activity and cytokine production of intestinal lamina propria leukocytes does not necessarily depend on β-glucan contents

We evaluated the effects of seven mushroom extracts (Grifola frondosa, Pholiota nameko, Panellus serotinus, Hypsizygus marmoreus, Pleurotus cornucopiae, Armillaria mellea, and Flammulina velutipes) on cytotoxic activity and cytokine production of lamina propria leukocytes (LPLs) isolated from rat small (S) and large (L) intestinal mucosa. Boiling water extracts from seven species of mushrooms showed no direct cytotoxicity against the YAC-1 target cells. However, prominent increases of cytotoxicity were observed in S- and L-LPLs co-cultured with P. serotinus extract. Cytokine production (TNFα, IFNγ, IL-12 p70, and IL-4) of S- and L-LPLs was stimulated in response to P. cornucopiae extract. Mushroom extracts contributed to target cell adhesion and/or cytokine production in the effector cells. The promotion of cytotoxic activity in S- and L-LPLs was not necessarily related to β-glucan content of the mushroom.     

Effect of drawing condition on mechanical properties and molecular orientation of self-reinforced poly(lactic acid) screws

Effects of extrusion ratio (ER) during extruding on mechanical properties of poly(lactic acid) (PLA) screws were investigated in terms of shear and twist strength. Shear strength increased by drawing, while twist strength decreased. This might be due to orientation of molecular chains during drawing. In order to evaluate orientation of molecular chains, orientation function in extruded billets was measured as a function of ER. Since orientation function increased with ER, drawing is effective method to improve shear strength of screw, where fibrous structure which was formed during extruding resisted shear stress in cross-section perpendicular to screw axis. Although orientation functions for billet extruded at ER 1.3–4 were equivalent, both strengths changed for the screw extruded at the range of this ER. Infrared spectra suggested transforming from α to β crystal for the billet extruded at the range of this ER. This result suggested that mechanical properties of screw also depended on the crystal forms.     

Biosynthesis of Trehangelin in Polymorphospora rubra K07–0510: Identification of Metabolic Pathway to Angelyl‐CoA

Trehangelins are trehalose angelates discovered from endophytic actinomycete Polymorphospora rubra K07‐0510. We identified the trehangelin biosynthetic gene cluster, including genes that encode a glycoside hydrolase‐like protein (thgC), α‐amylase (thgD), 3‐ketoacyl‐ACP synthase III (thgI), 3‐ketoacyl‐ACP reductase (thgK), enoyl‐CoA hydratase (thgH) and acyl transferase (thgJ). Heterologous expression of thgH, thgI, thgJ and thgK confirmed the importance of these genes in the biosynthesis of trehangelin A. Enzymatic activity studies showed that ThgI catalyses the condensation of acetyl‐CoA and methylmalonyl‐CoA to 2‐methylacetoacetyl‐CoA (MAA‐CoA), ThgK catalyses NADPH‐dependent reduction of MAA‐CoA to 3‐hydroxy‐2‐methylbutyryl‐CoA (HMB‐CoA) and ThgH catalyses the dehydration of HMB‐CoA to angelyl‐CoA (AN‐CoA). This is the first report on the elucidation of the enzymatic formation of AN‐CoA.     

The Role of a Nonribosomal Peptide Synthetase in l‐Lysine Lactamization During Capuramycin Biosynthesis

Capuramycins are one of several known classes of natural products that contain an l ‐Lys‐derived l ‐α‐amino‐?‐caprolactam (l ‐ACL) unit. The α‐amino group of l ‐ACL in a capuramycin is linked to an unsaturated hexuronic acid component through an amide bond that was previously shown to originate by an ATP‐independent enzymatic route. With the aid of a combined in vivo and in vitro approach, a predicted tridomain nonribosomal peptide synthetase CapU is functionally characterized here as the ATP‐dependent amide‐bond‐forming catalyst responsible for the biosynthesis of the remaining amide bond present in l ‐ACL. The results are consistent with the adenylation domain of CapU as the essential catalytic component for l ‐Lys activation and thioesterification of the adjacent thiolation domain. However, in contrast to expectations, lactamization does not require any additional domains or proteins and is likely a nonenzymatic event. The results set the stage for examining whether a similar NRPS‐mediated mechanism is employed in the biosynthesis of other l ‐ACL‐containing natural products and, just as intriguingly, how spontaneous lactamization is avoided in the numerous NRPS‐derived peptides that contain an unmodified l ‐Lys residue.