Search

We performed dielectric measurements of an evergreen conifer tree, Cryptomeria japonica, impregnated with various aqueous solutions along the fiber direction in the frequency range of 10 MHz to 10 GHz at room temperature to investigate the molecular description of water and solute molecules in void space of the wood. The Cole−Cole-type relaxation process reflecting the motion of the water and solute molecules is observed in the GHz region. The water content dependence of the shape of the dielectric relaxation spectra markedly deviates from that of bulk state, while the relaxation time is similar to that of each bulk solutions. This characteristic dielectric property is interpreted that the fractionation of the hydrogen bond network formed by water and solute molecules occurs caused by the molecules being constrained to the inner walls of the wood voids.

In order to monitor elderly people living alone, the authors constructed a simple daily monitoring system combining multiple wireless acceleration sensors, a wireless module, a microcomputer, and a cloud-based internet of things (IoT) service. The movements of objects in daily life were continuously recorded by detecting activations of the acceleration sensors of this system. By analyzing the acquired data, the daily life pattern of subjects, such as wake time, sleep time, and meal time, could be estimated. When interviewed, municipal welfare officers commented that these data would be useful for monitoring the daily life of elderly people.

Lychnis (Caryophyllaceae) consists of about 30 species distributed throughout the temperate regions of the Northern Hemisphere, from East Asia to Europe. Many Lychnis spp. have high ornamental value and cultivated as pot or garden plants. In the present study, in vitro chromosome doubling of several Lychnis spp. was examined in order to widen their variability in horticultural traits. Initially effect of various spindle toxin treatments [100, 500 or 1000 mg l−1 colchicine (COL), 10, 20 or 50 mg l−1 oryzalin (ORY), or 1, 5, 10 mg l−1 amiprophos-methyl (APM)] of nodal segments of a triploid genotype of L. senno (3x) was investigated on survival of nodal segments and chromosome doubling in nodal segment-derived plantlets. Significantly higher percentage (75.0%) of surviving segments after spindle toxin treatment was obtained in 10 mg l−1 ORY treatment. Flow cytometry (FCM) analysis of leaf tissues showed that 9.4–13.8% of plantlets, which were derived from 10 to 20 mg l−1 ORY, or 5 mg l−1 APM treatments, were hexaploid (6x) or ploidy chimera (3x + 6x, 4x + 6x, 5x + 6x, 3x + 4x + 6x). The results obtained by FCM analysis were confirmed by chromosome observation in root tip cells. Thus 10 mg l−1 ORY treatment of nodal segments is suitable for in vitro chromosome doubling of triploid L. senno. Efficient chromosome doubling was also achieved in diploid L. fulgens (2x) and L. sieboldii (2x) by treating nodal segments with 10 mg l−1 ORY: 68.9–88.7% of nodal segments survived after ORY treatment, and 24.7–26.5% of plantlets derived from ORY-treated nodal segments were tetraploid (4x) or ploidy chimera (2x + 4x) in both species. These results indicate that the in vitro chromosome doubling method established for triploid L. senno may be applicable to a wide range of Lychnis spp. Tetraploid L. fulgens and L. sieboldii showed a compact plant form, and had thick stems and deep green leaves compared with the diploid mother plants. On the other hand, hexaploid L. senno showed very poor growth and died before flowering.

Dielectric relaxation measurements were performed for rice kernels by time domain reflectometry (TDR) with flat-end coaxial electrodes. Difficulties in good contact between the surfaces of the electrodes and the kernels are eliminated by a TDR set-up with a sample holder for a kernel, and the water content could be evaluated from relaxation curves. Dielectric measurements were performed for rice kernels, rice flour and boiled rice with various water contents, and the water amount and dynamic behaviour of water molecules were explained from restricted dynamics of water molecules and also from the τ–β (relaxation time versus the relaxation-time distribution parameter of the Cole–Cole equation) diagram. In comparison with other aqueous systems, the dynamic structure of water in moist rice is more similar to aqueous dispersion systems than to aqueous solutions.

The Liliaceous perennial Tricyrtis hirta, sometimes called ‘Japanese toad lily’, has recently become popular as an ornamental for pot and garden uses. Highly embryogenic callus cultures of this plant predominately consisted of diploid cells but also contained tetraploid cells after 1 year of establishment. In the present study, plans regenerated from the 1-year-old embryogenic callus cultures were subjected to ploidy level analysis and morphological characterization following 3 years of cultivation. Among 37 plants examined, 28 kept the diploid level (2n = 2x = 26) but nine were tetraploid (2n = 4x = 52) as indicated by FCM analysis and chromosome observation. Although no morphological alterations were detected in 26 out of 28 diploid regenerants, the remaining two showed noticeable variations: both were severely dwarf and had crimped leaves and many malformed flowers. The tetraploid regenerants had several horticulturally attractive characteristics compared with the diploid controls, such as longer shoots, thicker stems, and larger flowers. Thus regeneration of tetraploid plants from 1-year-old embryogenic callus cultures offers a possibility to improve the horticultural value of T. hirta, although regeneration of trueness-to-type plants is essential for utilizing the cultures for micropropagation and genetic transformation.

Broadband dielectric spectroscopy measurements performed around the freezing temperature showed two different dynamical behaviors for various mixtures of poly(vinyl pyrrolidone) (PVP)/water, poly(vinyl acetate)(PVAc)/benzene, PVP/poly(ethylene glycol) (PEG), and 4,4′- n -pentylcyanobiphenyl (5CB)/benzene. A discontinuous behavior of the temperature dependence of the relaxation time around the freezing temperature was observed for the processes due to water in PVP/water, PVP in PVP/PEG, and 5CB in 5CB/benzene mixtures, and a continuous behavior was observed for PVAc in PVAc/benzene and PEG in PVP/PEG mixtures. These behaviors are explained by a large volume effect from the large motional unit. PVP/ n -alcohol mixtures support that the high hydrogen-bonding ability of water brings about the large volume effect also in PVP/water mixture.

Microwave dielectric measurements were performed in the frequency range from 1 mHz up to 30 GHz using a time domain reflectometry (TDR) method for emulsions and gels. Flat-end sample cells have been used in the TDR measurement to contact a small spot of the surface of those viscoelastic and solid samples without any destruction. Relaxation processes due to various water structures were observed for these aqueous systems. Relaxation parameters thus obtained offer information about these water structures and amounts. The relaxation strength obtained from the high frequency process due to free water can be an adequate measure of water content in spite of some ambiguities for different water structures in some materials. Comparisons of actual water contents in emulsion with those estimated from the relaxation strength indicate that water structure is affected by the interaction between water and micelle. Unfreezable water observed in DNA gel under the freezing point consists of bound water and a fraction of free water. Bound water molecules are still unfreezable to keep the double helical structure of DNA, when the fraction of free water is frozen at lower temperatures. These water structures determine physical properties of moist materials. TDR measuring technique with the flat-end cell is effective to investigate water structures in viscoelastic moist materials and to evaluate physical properties and structures of complex molecular systems.

Dielectric measurements on tetramethyl-bisphenol-A polycarbonate (TMPC), polystyrene (PS), and 50 wt% TMPC/PS blend were made in the frequency range of 0.1 mHz to 1 MHz at various temperatures. The α-relaxation process due to main-chain motions was observed for each polymer and the β-relaxation processes due to local motions of TMPC were observed for TMPC and TMPC/PS blend. Plots of logarithm of the relaxation time for the β process against the reciprocal of the absolute temperature were fit to Arrhenius functions for TMPC and the blend. However the relaxation strength and the shape parameter of the Cole–Cole equation had changes around the glass transition temperature, Tg. These changes in relaxation parameters around Tg was observed for the first time for the β process. Based on these results we suggest that even the local chain motions are affected by the glass transition phenomena, although the β process are not described by the Vogel–Fulcher–Tamman equation.

Dielectric relaxation processes for mortar observed by broadband dielectric spectroscopy were analyzed in the drying and hydration processes for an aging sample in the frequency region from 1 MHz up to 2 MHz. At least two processes for structured water in the kHz frequency region and another mHz relaxation process affected by ionic behaviors were observed. Comparison of the relaxation parameters obtained for the drying and hydration processes suggests an existence of hierarchical water structures in the exchange of water molecules, which are originally exchanged from free water observed at around 20 GHz. The water molecules reflected in the lower frequency process of the two kHz relaxation processes are more restricted and take more homogeneous structures than the higher kHz relaxation process. These structured water usually hidden in large ionic behaviors for wood samples was observed by electrodes covered by a thin Teflon film, and hierarchical water structures were also suggested for wood samples. Dielectric spectroscopy technique is an effective tool to analyze the new concept of hierarchical water structures in complex materials.