Micromorphology of epicuticular wax structures of the garden strawberry leaves by electron microscopy: Syntopism and polymorphism

Ultrastructural aspects of leaf epicuticular wax structures were investigated in the garden strawberry Fragaria × ananassa by scanning and transmission electron microscopy. Both the adaxial and abaxial surfaces of two cultivars (Maehyang and Red Pearl) were collected and subjected to surface observations and ultrathin sections. The most prominent leaf epicuticular wax structures included membraneous platelets and angular rodlets. Most wax platelets were membraneous, and appeared to protrude from the surface at an acute angle. Angular rodlets were usually bent and had rather distinct facets in the abaxial surface of the two cultivars. Membraneous platelets were predominant on the adaxial surface of Maehyang, whereas the adaxial surface of Red Pearl was characterized by angular rodlets. However, both cultivars possessed angular rodlets on the abaxial surface, simultaneously. The combination of air-drying without vacuum and in-lens imaging of secondary electron signals with a field emission gun could impart the superb resolution at low electron dose with minimal specimen shrinkage. In vertical profiles of the leaf epidermis, epicuticular waxes were observed above the cuticle layer, and measured approximately as 50 nm in thickness. The natural epicuticular waxes were seemingly mixtures of electron-dense microfibrils, and heterogeneous in shape on ultrathin sections. Distinct crystal-like strata could be hardly discernable in the wax structures. These results suggest that the garden strawberry has the nature of syntopism within one plant and polymorphism within the same species in the formation and occurrence of leaf epicuticular waxes.     

Design variable tolerance effects on the natural frequency variance of constrained multi-body systems in dynamic equilibrium

The design variable tolerance effects on the natural frequency variance of constrained multi-body systems in dynamic equilibrium are investigated in this study. Monte-Carlo simulation is often employed for such investigations, but it is known to have serious drawbacks. Excessive amount of computation time needs to be consumed since a large number of evaluations are usually required for the method. Furthermore, the solution accuracy cannot be always guaranteed in spite of the excessive amount of computation time. In order to overcome such drawbacks, a method employing eigenvalue sensitivity information is proposed to obtain the variance of natural frequency in this study. In order to verify the accuracy and the efficiency of the method, some numerical examples of multi-body systems in dynamic equilibrium are solved and the results are compared to those obtained by an analytical method and Monte-Carlo simulation.     

MR microscopy of micron scale structures

Magnetic resonance (MR) microscopy of up to 1–5-μm resolutions have been reported previously. The tested phantom structures, however, had widths one order of magnitude bigger than the reported resolutions, e.g., spherical beads or capillary tubes of tens-of-micron diameters or wall thicknesses have been imaged. In this study, we fabricated structures having a few micron widths on a silicon wafer and imaged them using our 1-μm-resolution MR microscopy at 14.1 T. Micron scale width structures were, for the first time, resolved by MR microscopy.     

Magnetic properties of neutron irradiated RPV steel

The neutron irradiated reactor pressure vessel (RPV) steels at various dose of 0–10¹⁸ n/cm² have been studied with Mössbauer, x-ray diffraction, and VSM. The Mössbauer data shows that the value of magnetic hyperfine field of Fe atom that exist at martensite is 330 kOe at site 1 and 305 kOe at site 2. At room temperature, the total absorption area of Mössbauer spectra with respect to irradiation of neutron is constant for the dose of 0–10¹⁶ n/cm², while over the dose of 0–10¹⁷ n/cm² the absorption area decreases rapidly. But the doublet area for the dose of 0–10¹⁶ n/cm² is constant, while over the dose of 10¹⁷ n/cm² it increases with increasing the fluence level of neutron. The coercivity and remanence of the neutron irradiated samples do not change significantly. But the maximum induction decreases by 5% at 10¹⁸ n/cm², compared with that of the as-received sample.     

Viscosity Properties for Aqueous Solution of Urethane Acrylate Cationomer

Abstract

Water-soluble and UV-curable urethane acrylate cationomer was synthesized incorporating N-methyldiethanol amine (MDEA) on the molecular backbone and its viscosity properties were examined with respect to shear rate, temperature, and weight fraction of resin. All shear rates showed shear rate independence within given fraction regions. The viscosity trends of urethane acrylate cationomer solutions followed the Arrhenius equation well. The logarithmic infinite viscosity and activation energy showed linear relationship with the fraction below the weight fraction of 0. 325. However, above the fraction of 0. 325, the deviation from linear relationship was observed. This was believed to be attributed to the intermolecular interactions among molecular chains. From the obtained linear correlation of the logarithmic infinite viscosity and activation energy with the fraction, rheological equation of state was proposed. The viscosities obtained from the equation of state successfully corresponded to the results of experiments.     

Simultaneous Determination of α- and γ-Mangostins in Mouse Plasma by HPLC–MS/MS Method: Application to a Pharmacokinetic Study of Mangosteen Extract in Mouse

Recently, extracts from the pericarp of mangosteen, Garcinia mangostana L., exhibited various pharmacological properties such as anti-oxidative, anti-inflammatory, anti-bacterial and chemopreventive activities. Albeit it has diverse application, there is little information about its pharmacokinetic aspects. Thus, the present study was undertaken to develop the simultaneous determination of α- and γ-mangostins (α- and γ-MG), major and active compounds, from extracts for the application of pharmacokinetic studies in mice using combined liquid chromatography–tandem mass-spectrometry and microsampling systems. The intra- and inter-validation, precision, accuracy, stability, recovery and matrix effects of α- and γ-MG were conducted in mouse plasma. Based on the developed analytical methods, pharmacokinetic parameters of α- and γ-MG after intravenous and oral administration of mangosteen extract were calculated. In sample preparation steps, the biological samples were deproteinized by acetonitrile and chromatographic separation was accomplished on a C₁₈ column. The detection was accomplished by multiple-reaction monitoring scanning after electrospray ionization source in the positive ionization mode. The optimized mass transition ion pairs (m/z) for quantitation were 411.062 → 354.900, 397.384 → 340.900, and 808.379 → 527.200 for α- and γ-MG and docetaxel (internal standard), respectively. The total run time was 5 min. The results provided a meaningful basis for the preclinical and clinical application of mangosteen extract.     

New Cyclization Route to the Skeletons of Lennoxamine and Chilenine

A new cyclization route, triggered by epoxide opening, has been performed to provide the key intermediates for isoindolobenzapine alkaloids, lennoxamine and chilenine. The epoxide was prepared by the Stille reaction using vinyltributylstannane and the following dioxirane treatment. Cyclization under the treatment of BF₃ · OEt₂ provided an azepine moiety, and the oxidative cyclization toward the known precursor for the alkaloids has been achieved by reaction with a stoichiometric amount of Pd(OAc)₂. This formal synthesis suggests a new route to the alkaloids.     

Culation of partial molar volume and its components for molecular dynamics models of dilute solutions

This paper is a review of our recent computational studies of volumetric characteristics using computer models of dilute solutions. Partial molar volume (PMV) and its components are calculated for simple and complex molecules in water (methane, noble gases, surfactants, polypeptides). Advantages and disadvantages of various computational methods are discussed. It is proposed to use the Voronoi-Delaunay technique to determine the reasonable boundary between a solute molecule and solvent molecules and to identify the PMV components related to the molecule, the boundary layer, and the solvent. It is noted that the observed increase in PMV with temperature for large molecules is due to an increase in the volume of voids in the boundary layer, i.e., due to the “thermal volume.” In this case, the solvent gives a negative contribution to the PMV. In contrast, for simple molecules (methane), the contribution from the solvent is positive and is the main factor in the increase in the PMV, which is associated with a specific change in water structure around a spherical hydrophobic particle outside the boundary layer. For surfactant molecules, the contribution from the solvent changes sign (from negative to positive) with increasing temperature.