Mass balance method for purity assay of phthalic acid esters: development of primary reference materials as traceability sources in the Japan Calibration Service System

Purity assay of high-purity materials (HPMs) of phthalic acid esters (PAEs) was carried out by means of a mass balance method. In this method, chromatographic methods such as gas chromatography-flame ionization detector (GC-FID) and/or high-performance liquid chromatography (HPLC) in combination with other methods such as Karl-Fischer (KF) titration and vacuum evaporation (VE) were applied. The sum of the impurities estimated by these methods allowed the estimation of the purity of the main component by difference. Seven PAEs with varying side chain structures and levels of impurities were analysed on a systematic way in which impurities were classified into several groups in terms of their abundance, availability of qualitative information and availability of authentic compounds, etc. The absolute quantity of each impurity was determined by GC-FID and/or HPLC based on the calibration made by the authentic compounds of impurities whenever available. The purities in mass fraction of these PAEs were certified at the National Metrology Institute of Japan (NMIJ), and the PAEs were registered as primary reference materials playing an essential role in linking the metrological traceability of the Japan Calibration Service System (JCSS) to the International System of Units (SI).     

Copper-catalyzed benzylic C-H oxygenation under an oxygen atmosphere via N-H imines as an intramolecular directing group

Copper-catalyzed benzylic C-H oxygenation under an oxygen atmosphere was developed starting from carbonitriles and Grignard reagents via N-H imine intermediates. The present process is characterized by the following two-step sequence in a one-pot manner: (1) addition of Grignard reagents to carbonitriles to form N-H imines and (2) benzylic C-H oxygenation (C═O bond formation) triggered by 1,5-hydrogen atom transfer with transient iminyl copper species.     

Halichonines A, B, and C, novel sesquiterpene alkaloids from the marine sponge Halichondria okadai Kadota

Novel sesquiterpene alkaloids, halichonines A (1), B (2), and C (3), were identified from the marine sponge Halichondria okadai Kadota. By spectroscopic analyses and synthesis, their structures were revealed to include a 6,6-bicyclic ring system and two prenylated amine moieties. In addition, 2 induced apoptosis in HL60 human leukemia cells.     

Crystal plasticity analysis of texture development in magnesium alloy during extrusion

The texture development mechanism during the extrusion of magnesium alloy is investigated by experimental observation and numerical analysis. First, we perform a finite element analysis of a full extrusion process using a phenomenological constitutive equation, and it is confirmed that the loading condition of the extrusion process near the central axis of the billet is approximated by an equi-biaxial compression mode. Then, the equi-biaxial compression problem is adopted as a simplified boundary value problem to be solved using a crystal plasticity model to clarify the detailed texture development mechanism during the extrusion process. The crystal plasticity analysis of equi-biaxial compression successfully reproduces the texture development from an initial random texture to the final experimentally observed texture. The effects of the deformation modes (i.e. slip and twinning systems) implemented in the calculation and the reference stress ratio of basal to nonbasal slip systems on texture development are studied in detail. Finally, the mechanism of texture development during the extrusion process is discussed in terms of the lattice rotation caused by the activated slip systems.     

Experimental study on vibrations of a nonwoven fabric cylindrical filter

Unexpected vibrations on a cylindrical filter made of nonwoven fabrics were clarified experimentally. Two types of filter with length L=1.8 m and 3.7 m, both 45 cm in diameter and 1.08 mm in thickness, were used. This is a new type of aeroelastic vibration phenomenon because the filter is a closed cylindrical vessel. In addition, the flow velocity of inner air was very slow and inner air flowed out slowly from the filter surface. The velocity distribution of air flow from a fan duct as well as the frequency and amplitude of the filter vibration were measured for two types of filter. By setting up a roll core panel at the outlet of the fan duct, we could rectify the outflow and suppressed the vibration of the shorter filter with L=1.8 m. However, this method was not adequate for the longer filter with L=3.7 m, and we could suppress the vibration by shielding the inner surface of the filter at the top region.     

Estimation of the lead–lag parameter between two stochastic processes driven by fractional Brownian motions

Statistical Inference for Stochastic Processes - In this paper, we consider the problem of estimating the lead–lag parameter between two stochastic processes driven by fractional Brownian...     

Scanning near-field optical/atomic force microscopy for fluorescence imaging and spectroscopy of biomaterials in air and liquid: Observation of recombinantEscherichia coli with gene coding to green fluorescent protein

We have developed a system of scanning near-field optical/atomic force microscopy (SNOM/AFM) for fluorescence imaging and spectroscopy of biomaterials in air and liquid. SNOM/AFM uses a bent optical fiber simultaneously as a dynamic force AFM cantilever and a SNOM probe. Optical resolution of SNOM images shows about 50 nm in an illumination mode for a standard sample of a patterned chromium layer of 20 nm thickness on a quartz glass plate. The SNOM/AFM system contains a photon counting system and polychrometer/ICCD (intensified charge coupled device) system for observation of the fluorescence image and spectrograph of micro areas, respectively. The gene coding to green fluorescence protein (GFP) was cloned in recombinantEscherichia coli (E. coli). Topography, fluorescence image and spectrograph of recombinantE. coli by SNOM/AFM showed a difference in fluorescence in individualE. coli. Fluorescence activity of GFP can thus be used as a convenient indicator of transformation. SNOM/AFM is also applicable to observe immobilizedE. coli on a glass plate in water with a liquid chamber and may allow the viewing of observation of floating organisms.     

Positron annihilation in dextro and laevo amino acid

High-precision positron lifetime spectra in tryptophan do not confirm the pronounced asymmetries in the interaction of positrons from radioactive sources with the d and l forms that were reported earlier and quoted as a cause for the the evolution of living matter with laevo amino acids.