Ductility and toughenability study of epoxy resins under multiaxial stress states

The local strains in unmodified and rubber-modified epoxies under multiaxial stress states were examined. Matrix ductility was varied by using epoxide resins of different epoxide monomer molecular weights. The stress state was altered from a plane strain case to a plane stress case by varying the thickness of the test specimens. It was confirmed that, in the case of unmodified resins, the thinner specimens which experienced nearly uniaxial tensile stress exhibited much higher local strains at failure than the thicker counterparts which experienced highly triaxial tensile stress. Also, the cross-link density was reduced as monomer molecular weight increased, thus the increase in local plastic strain due to the stress state change also became greater. Furthermore, it was found that rubber modification markedly increased the plastic strain to failure, irrespective of the specimen dimensions, and that the extent of this plastic strain increased as cross-link density was lowered. These results are consistent with the concept that the cavitation of rubber particles relieves the initial multiaxial constraint in a thick specimen, induces a stress state closer to plane stress throughout the specimen, and consequently enables the matrix to deform to a larger extent. The results also show clearly that the toughenability of a matrix resin is not independent of the stress state and the matrix ductility.     

Conventional detection of 2,4-dinitrophenol using quartz crystal microbalance

We present conventional detection of 2,4-dinitrophenol (DNP) for using the competitive reaction between DNP and DNP-conjugated albumin onto DNP antibody immobilized quartz crystal microbalance (QCM). This QCM method allows detection of DNP concentration in the range of 0.01 to 100 ng/ml; linear correlation obtains DNP concentration from 1 to 100 ng/ml.     

Determination method of isocitric acid in food additive citric acid

A simple and rapid method using HPLC was developed for the determination of isocitric acid in food additive citric acid. One gram of sample was dissolved in 100 mL of water. HPLC separation was performed on an Inertsil ODS-3 column (4.6 mm i.d. x 250 mm) using 0.1% phosphoric acid as the mobile phase at a flow rate of 1 mL/min. Isocitric acid was detected at 210 nm. The calibration graph was rectilinear from 5 to 100 micrograms/mL. The recoveries of isocitric acid from sample at the levels of 0.1% and 0.4% were 98% and 99%, respectively, and the determination limit was 0.05%.     

Origin of sennosides in health teas including Malva leaves

The aim of this study is to clarify whether sennosides are contained in the leaf of Malva verticillata L., and then to clarify the source of sennosides in health teas including malva leaves. The identification and determination of sennosides were performed with thin layer chromatography and high performance liquid chromatography. The leaf of Malva verticillata L. did not contain sennosides A or B and could be easily distinguished from senna leaf. Our previous report showed that sennosides are contained in weight-reducing herbal teas including malva leaves, and that senna leaf is a herbal component in some teas. Furthermore, in 10 samples of health tea including malva leaves that were bought last year, the smallest amount of sennosides was 6.1 mg/bag, and all health teas including malva leaves contained the leaf and midrib of senna. We suggest that sennosides A and B are not contained in the leaf of Malva verticillata L., and that the sennosides in health teas including malva leaves are not derived from malva leaf but from senna leaf.     

Information-theoretic investigation of impact of huggable communication medium on prefrontal brain activation*

This paper examines the effect of mediated hugs that are achieved with a huggable communication medium on the brain activities of users during conversations. We measured their brain activities with functional near-infrared spectroscopy (NIRS) and evaluated them with two information theoretic measures: permutation entropy, an indicator of relaxation, and multiscale entropy, which captures complexity in brain activation at multiple time scales. We first verify the influence of lip movements on brain activities during conversation and then compare brain activities during tele-conversation through a huggable communication medium with a mobile phone. Our analysis of NIRS signals shows that mediated hugs decrease permutation entropy and increase multiscale entropy. These results suggest that touch interaction through a mediated hug induces a relaxed state in our brain but increases complex patterns of brain activation.     

Preparation and characterization of Z-type hexaferrites, Ba3(1−x)Sr3x Co2Fe24O41 with x = 0–0.5, via a two-step calcination with an intermediate wet milling

Z-type hexaferrites (Ba_{3(1 − x)}Sr_3x Co₂Fe₂₄O₄₁with x = 0–0.5, Z-hex) were prepared in a nearly phase pure state by a two-step calcination with an intermediate wet milling. The first calcination of the starting mixture comprising oxides or hydroxides at temperatures below 1100^∘C brought about a mixture of layer-structured M and Y-type hexaferrite phases, together with a spinel phase of Co ferrite. Z-hex was fully crystallized after the second calcination up to 1230^∘C. Wet milling between the two calcination steps was decisive for the phase purity. Emphasis was laid on the quantitative analyses of Z-hex, together with the evaluation of anisotropic growth of the crystallites. Sr addition stabilizes Z-hex, while decreases degree of anisotropy simultaneously.     

Effect of medium-chain fatty acid positional distribution in dietary triacylglycerol on lymphatic lipid transport and chylomicron composition in rats

The present study was carried out to examine if the positional distribution of medium-chain fatty acid (MCF) in dietary synthetic fat influences lymphatic transport of dietary fat and the chemical composition of chylomicrons in rats with permanent cannulation of thoracic duct. Four types of synthetic triacylglycerol were prepared: (i) sn-1(3) MCF-sn 2 linoleic acid, (ii) interesterified sn-1(3) MCF-sn 2 linoleic acid, (iii) sn-2 MCF-sn-1(3) linoleic acid, and (iv) interesterified sn-2 MCF-sn-1(3) linoleic acid. A purified diet composed of equal amounts of the synthetic fat and cocoa butter was given to rats with permanent lymph duct cannulation. The positional distribution of MCF in the dietary fat had no significant effect on the lymph flow, triacylglycerol output, phospholipid output, lipid composition of chylomicrons, or the particle size. The positional distribution of MCF in the synthetic triacylglycerol was maintained in the chylomicron triacylglycerol. These results showed that MCF in the dietary triacylglycerol is transported into lymphatics and the positional distribution is well preserved in chylomicron triacylglycerol.     

Hydrocarbons with a homoconjugated polyene system and their monoepoxy derivatives: Sex attractants of geometrid and noctuid moths distributed in Japan

Although several sex pheromones of the family Geometridae have been characterized, investigations on Japanese species are limited. In order to obtain more information, screening using known sex pheromones and their analogs was carried out. The (Z,Z,Z)-3,6,9-triunsaturated and (Z,Z)-6,9-diunsaturated hydrocarbons with straight C¹⁹-C²¹ chains were synthesized by the Grignard coupling reaction as a key step starting from linolenic and linoleic acids, respectively. Oxidation of the homoconjugated trienes withm-chloroperoxybenzoic acid yielded a 111 mixture of three monoepoxy derivatives that could be separated by silica gel chromatography. The chemical structure of each positional isomer was confirmed using two-dimensional NMR techniques and MS measurements, which enabled characteristic fragment ions from the isomers to be identified. Field tests using lures incorporating only one of the above six hydrocarbons or nine epoxides were carried out in a forest in Tokyo. Consequently, attraction of male moths of 14 geometrid species in addition to four species in another family, the Noctuidae, was observed. It was concluded that hydrocarbons with a homoconjugated polyene system and the monoepoxy derivatives are important components of sex pheromones produced by Japanese lepidopterous insects, particularly the geometrid moths.     

Note: Zr(IV)-Immobilized Resin Prepared by Surface Template Polymerization for Fluoride Ion Removal

Abstract

A novel adsorbent Zr(IV)-immobilized resin was prepared to remove fluoride ions from tap water and industrial wastewater. In order to enhance both the kinetics and efficiency, large pathways were formed in the resin for fluoride ion adsorption and the Zr(IV)-phosphate complexes were immobilized on the polymer surface by surface-template polymerization. The Zr(IV)-immobilized resin had a fluoride adsorption capacity of 0.30 mmol/g. The morphology of the Zr(IV)-immobilized resin was evaluated by measuring the specific surface area, pore volume, and pore size distribution. The resin possessed large amounts of large macropores with diameters around 300 nm. The molecular structure at the fluoride adsorption sites was investigated by measuring the amounts of phosphorus, zirconium, and fluoride ion in the resin, and developing a model complex using computational chemistry. On the polymer surface, a fluoride ion/Zr(IV)/dioleyl phosphoric acid complex with an ideal F:Zr:P mole ratio of 3:1:3 could be formed.