Development and degradation of graphitic microtexture in carbon nanospheres under a morphologically restrained condition

Graphitic microtexture in carbon nanospheres (CNSs, average diameter = 500–1000 nm) formed by a heat-treatment between 2000 °C and 2900 °C was investigated with XRD, Raman spectrum, SEM and TEM. By the heat-treatment up to 2000 °C, CNS particles in any size were polyhedronized. In the microtexture of polyhedronized CNS particles thus obtained, graphitic stacking structure of aromatic layers was well developed in the polyhedron face regions, while an aggregation of column-like crystallite was confirmed in the polyhedron ridge region. It was also shown that some ridges of CNSs with the average diameter over 700 nm were collapsed by the heat-treatment at 2900 °C. These collapses include an exfoliation of aromatic layers in which the torn layers have hairpin-like microtexture at their ends, and a crack of layer stacks with adjacent layer stacks. According to a direct examination with TEM, it was clarified that a ratio of ridges with either type of damage to a total number of ridges is obviously higher in CNS particles with larger diameter. This phenomenon was discussed in relation to the high crystallinity in the polyhedron face regions and the aggregation of structural defects in the ridge regions.     

The mixed coculture effect of primary rat hepatocytes and bone marrow cells is caused by soluble factors derived from bone marrow cells

Heterospheroids consisting of hepatocytes and bone marrow cells (BMCs) are formed by the mixed coculture of these cells and enhance the expression and maintenance of the liver-specific functions of hepatocytes. Not only the soluble factors derived from these cells, but also functional organoid (heterospheroid) formation, are considered to underlie this coculture effect. Therefore, in the present study, we aimed to clarify the mechanism of this co-culture effect. We performed hepatocyte monoculture with conditioned media prepared from hepatocyte cultures, BMC cultures and a coculture of hepatocytes and BMCs. When using any type of conditioned medium, no hepatocyte spheroids formed, and the hepatocytes formed a monolayer. In addition, an effect for these conditioned media was shown in terms of the albumin production and ammonia metabolism activities of the hepatocytes; conditioned medium from BMCs showed the strongest effect. The monocultured hepatocytes in the conditioned medium derived from BMCs showed equivalent albumin production and ammonia metabolism activities to the cocultured spheroids of hepatocytes and BMCs. Therefore, it was determined that the effect of the coculture of hepatocytes and BMCs was caused by soluble factors derived from BMCs.     

High throughput and exhaustive analysis of diverse lipids by using supercritical fluid chromatography-mass spectrometry for metabolomics

We have developed an analytical system that enables the simultaneous rapid analysis of lipids with varied structures and polarities through the use of supercritical fluid chromatography-mass spectrometry (SFC-MS). The separation conditions for SFC (column, modifier, back pressure, etc.) and the detection conditions for mass spectrometry (ionization method, parameters, etc.) were investigated to develop a simultaneous analytical method for lipid mixtures that included phospholipids, glycolipids, neutral lipids, and sphingolipids. When cyanopropylated silica gel-packed column was used for the separation, all lipids were successfully detected and the analysis time was less than 15 min. The use of an octadecylsilylated column resulted in separation, which was dependent on the differences in the unsaturation of the fatty acid side chains and isomer separation. This system is a powerful tool for studies on lipid metabolomics because it is useful not only as a fingerprinting method for the screening of diverse lipids but also for the detailed profiling of individual components.     

Physicochemical Characteristics of Starches of Two Sets of Near‐isogenic Wheat Lines with Different Amylose Content

Wheat lines with modified amylose content were produced by controlling the null alleles of three homoeologous Wx loci, Wx‐A1, Wx‐B1 and Wx‐D1 and those with triple‐null Wx alleles were found to yield waxy, amylose‐free starch. In this study, the new near‐isogenic lines developed by the recurrent backcross method between cv. Kanto 107 and the waxy mutant lines, K107Wx1 or K107Wx2, were cultivated and the physicochemical characteristics of their starches were investigated. The apparent amylose contents of the waxy near‐isogenic lines were 1.6 – 3.8%, whereas those of the non‐waxy near‐isogenic lines were 23.2 – 25.4%. The waxy lines had higher gelatinization temperature and enthalpy than the non‐waxy lines and no peak of amylose‐lipid complex as determined by DSC. The X‐ray diffraction patterns from both waxy and non‐waxy near‐isogenic lines corresponded to A‐type crystallization, like their parent lines. The starches isolated from the waxy lines had lower pasting onset and peak temperatures, higher peak viscosities and breakdown and lower final viscosity than those of the non‐waxy lines in the Viscoamylograph. The starch of non‐waxy near‐isogenic lines had lower peak and final viscosities and higher breakdown than did the recurrent parent line, cv. Kanto 107. The characteristics of the new wheat starches were well understood and classified, which will contribute to the wide application of these starches in food processing.     

Effects of the Barley amo1 and wax Genes on Starch Structure and Physicochemical Properties

Starch structural mutants showing abnormal endosperm characteristics have been used for investigating the effects of the mutation on structure and physicochemical properties of starches. Inbred lines of barley cultivars ‘Shikoku Hadaka 97’ and ‘Glacier AC38’ were used to investigate the impact of amo1 and waxy genes on starch properties. The amo1 type starch had high apparent amylose content and low starch content. The amo1+waxy type starch contained very little amylose. The content of long chains of amylopectin as detected with high‐performance size‐exclusion chromatography (HPSEC) was decreased, and that of amylopectin chains with the degree of polymerization (DP) of 12‐36 was increased in amo1 and amo1+waxy type starches. The amo1 and amo1+waxy type starches exhibited high gelatinization temperatures and low gelatinization enthalpies.     

Isolation of halotolerant Lactococcus lactis subsp. lactis from intestinal tract of coastal fish

We isolated lactic acid bacteria from the intestinal tract of the pufferfish Takifugu niphobles caught in Shimoda, Shizuoka, Japan by using MRS broth prepared with 50% seawater. Additional screening was carried out using phenotypic tests such as Gram staining, cell morphology, catalase, oxidase and fermentation of glucose. Subsequently 227 isolates screened by the phenotypic tests were subjected to species-specific PCR for Lactococcus lactis, resulting in four positive isolates. The 16S rRNA gene sequences from three isolates were highly similar to that of L. lactis subsp. lactis (DNA database accession number M58837), while that of one isolate was identical to that of Leuconostoc mesenteroides (AB023246). These isolates were characterized by API 50 CH for carbohydrate fermentation and other phenotypic criteria for salt tolerance, and the characteristics were compared with those of L. lactis subsp. lactis from a cheese starter culture. The carbohydrate fermentation profiles of these isolates were characteristic of L. lactis subsp. lactis strains, whereas the tolerance of these isolates to salt was higher than that of L. lactis subsp. lactis from the cheese starter culture: the new L. lactis isolates showed high salt tolerance in MRS-agar plates containing 200% seawater or 6% sodium chloride. This is the first report of the isolation of halotolerant strains of L. lactis subsp. lactis from a marine environment.     

Organic photoconductive device fabricated by electrospray deposition method

We demonstrated a blue-sensitive organic photoconductive device fabricated by an electrospray deposition method. Poly[9,9-dioctylfluorenyl-2,7-diyl]-co-1,4-benzo-(2,1,3)-thiadiazole (F8BT) was chosen as a blue-sensitive polymer, and a maximum external quantum efficiency of 0.22% was achieved at the irradiated optical intensity of 3.9 mW/cm². The absorption spectrum of F8BT neat film showed that the selectivity of spectral responses at the blue wavelength region was good enough to divide the incident light into blue color components. These results indicate the possibility of a color separation without a prism for high resolution cameras by combination of green and red sensitive organic photoconductive devices.     

Supercooled liquid foaming of a Zr-Al-Cu-Ag bulk metallic glass containing pressurized helium pores

Foaming of a Zr-based metallic glass in the supercooled liquid is successfully performed by introducing pressurized pores and subsequent isochronal annealing. Melting of a Zr₄₈Cu₃₆Al₈Ag₈ powder under 12 MPa pressurized helium atmosphere followed by water quenching introduces spherical helium pores, whose average diameter and volume fraction are estimated respectively to be 30 μm and 7%, into a fully glassy bulk Zr₄₈Cu₃₆Al₈Ag₈ alloy. The isochronal annealing of the porous alloy below the crystallization temperature under atmospheric pressure of argon enables the expansion of pores by viscous flow deformation of the supercooled liquid, resulting in a high porosity structure up to 70% with a uniform cell size and cell distribution.     

Behaviour of piezoelectric lead zirconate titanate irradiating with high-energy xenon ions

The characteristics of a detector fabricated using piezoelectric lead zirconate titanate (PZT) were studied by irradiating it with a 400 MeV/n xenon (Xe) beam while changing the beam flux intensity. The largest output signal was observed from the detector when the beam power per unit time was estimated to be largest. It was also found that the sensitivity per Xe ion of the detector seemed to be higher with decreasing the amount of the Xe ion flux within the limits of the experimental conditions.     

Real and reciprocal space order parameters for porous arrays from image analysis

A real space technique based on the pair distribution function (PDF) and a reciprocal space method utilizing a 2D fast Fourier transform (FFT) quantify the order in porous arrays. Porous arrays fabricated from nanoscience technology are analyzed. The PDFs are fit with a series of Gaussian curves and the widths of the Gaussian peaks are used to model the linear strain in the array. An order parameter is defined from the PDF and takes values from [0,1], where the value 1 represents an ideal array. The radial distribution function (RDF) is also determined for the porous arrays. The FFT of the porous arrays is used to generate an order parameter as a ratio of intensity to the full width at half maximum (σ) of the peaks. Defined as relative intensity , this parameter takes values from [0,∞], where larger values represent more order in the array. We use a variety of available software to generate this data.